Merge pull request 'update main 21.11.23' (#2) from Bananymous/banan-os:main into main

Reviewed-on: Sinipelto/banan-os#2

.gitignore

@@ -1,7 +1,5 @@
-*.img
-isodir
-sysroot
 .vscode/
 .idea/
-bochsrc
-bx_enh_dbg.ini
+build/
+base/
+script/fakeroot-context

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "kernel/lai"]
+	path = kernel/lai
+	url = https://github.com/managarm/lai.git
+	ignore = untracked

BAN/BAN/Memory.cpp

@@ -1,9 +0,0 @@
-#include <BAN/Memory.h>
-
-void* operator new(size_t size)								{ return BAN::allocator(size); }
-void* operator new[](size_t size)							{ return BAN::allocator(size); }
-
-void operator delete(void* addr)							{ BAN::deallocator(addr); }
-void operator delete[](void* addr)							{ BAN::deallocator(addr); }
-void operator delete(void* addr, size_t)					{ BAN::deallocator(addr); }
-void operator delete[](void* addr, size_t)					{ BAN::deallocator(addr); }

BAN/BAN/New.cpp

@@ -0,0 +1,9 @@
+#include <BAN/New.h>
+
+void* operator new(size_t size)				{ return BAN::allocator(size); }
+void* operator new[](size_t size)			{ return BAN::allocator(size); }
+
+void operator delete(void* addr)				{ BAN::deallocator(addr); }
+void operator delete[](void* addr)			{ BAN::deallocator(addr); }
+void operator delete(void* addr, size_t)		{ BAN::deallocator(addr); }
+void operator delete[](void* addr, size_t)	{ BAN::deallocator(addr); }

BAN/BAN/String.cpp

@@ -1,102 +1,109 @@
-#include <BAN/Errors.h>
-#include <BAN/Math.h>
-#include <BAN/Memory.h>
-#include <BAN/Move.h>
 #include <BAN/String.h>
-#include <BAN/StringView.h>
-
-#include <string.h>
+#include <BAN/New.h>
 
 namespace BAN
 {
 
 	String::String()
 	{
-		MUST(copy_impl(""sv));
 	}
 
 	String::String(const String& other)
 	{
-		MUST(copy_impl(other.sv()));
+		*this = other;
 	}
 
 	String::String(String&& other)
 	{
-		move_impl(move(other));
+		*this = move(other);
 	}
 
 	String::String(StringView other)
 	{
-		MUST(copy_impl(other));
+		*this = other;
 	}
 
 	String::~String()
 	{
-		BAN::deallocator(m_data);
+		clear();
 	}
 
 	String& String::operator=(const String& other)
 	{
-		MUST(copy_impl(other.sv()));
+		clear();
+		MUST(ensure_capacity(other.size()));
+		memcpy(data(), other.data(), other.size() + 1);
+		m_size = other.size();
 		return *this;
 	}
 
 	String& String::operator=(String&& other)
 	{
-		BAN::deallocator(m_data);
-		move_impl(move(other));
+		clear();
+
+		if (other.has_sso())
+			memcpy(data(), other.data(), other.size() + 1);
+		else
+		{
+			m_storage.general_storage = other.m_storage.general_storage;
+			m_has_sso = false;
+		}
+		m_size = other.m_size;
+
+		other.m_size = 0;
+		other.m_storage.sso_storage = SSOStorage();
+		other.m_has_sso = true;
+
 		return *this;
 	}
 
 	String& String::operator=(StringView other)
 	{
-		MUST(copy_impl(other));
+		clear();
+		MUST(ensure_capacity(other.size()));
+		memcpy(data(), other.data(), other.size());
+		m_size = other.size();
+		data()[m_size] = '\0';
 		return *this;
 	}
 
-	ErrorOr<void> String::push_back(char ch)
+	ErrorOr<void> String::push_back(char c)
 	{
-		TRY(ensure_capacity(m_size + 2));
-		m_data[m_size] = ch;
+		TRY(ensure_capacity(m_size + 1));
+		data()[m_size] = c;
 		m_size++;
-		m_data[m_size] = '\0';
+		data()[m_size] = '\0';
 		return {};
 	}
 
-	ErrorOr<void> String::insert(char ch, size_type index)
+	ErrorOr<void> String::insert(char c, size_type index)
 	{
 		ASSERT(index <= m_size);
-		TRY(ensure_capacity(m_size + 1 + 1));
-		memmove(m_data + index + 1, m_data + index, m_size - index);
-		m_data[index] = ch;
-		m_size += 1;
-		m_data[m_size] = '\0';
+		TRY(ensure_capacity(m_size + 1));
+		memmove(data() + index + 1, data() + index, m_size - index);
+		data()[index] = c;
+		m_size++;
+		data()[m_size] = '\0';
 		return {};
 	}
 
-	ErrorOr<void> String::insert(StringView other, size_type index)
+	ErrorOr<void> String::insert(StringView str, size_type index)
 	{
 		ASSERT(index <= m_size);
-		TRY(ensure_capacity(m_size + other.size() + 1));
-		memmove(m_data + index + other.size(), m_data + index, m_size - index);
-		memcpy(m_data + index, other.data(), other.size());
-		m_size += other.size();
-		m_data[m_size] = '\0';
+		TRY(ensure_capacity(m_size + str.size()));
+		memmove(data() + index + str.size(), data() + index, m_size - index);
+		memcpy(data() + index, str.data(), str.size());
+		m_size += str.size();
+		data()[m_size] = '\0';
 		return {};
 	}
 
-	ErrorOr<void> String::append(StringView other)
+	ErrorOr<void> String::append(StringView str)
 	{
-		TRY(ensure_capacity(m_size + other.size() + 1));
-		memcpy(m_data + m_size, other.data(), other.size());
-		m_size += other.size();
-		m_data[m_size] = '\0';
-		return {};
-	}
-
-	ErrorOr<void> String::append(const String& string)
-	{
-		TRY(append(string.sv()));
+		TRY(ensure_capacity(m_size + str.size()));
+		memcpy(data() + m_size, str.data(), str.size());
+		m_size += str.size();
+		data()[m_size] = '\0';
 		return {};
 	}
 
@@ -104,159 +111,159 @@ namespace BAN
 	{
 		ASSERT(m_size > 0);
 		m_size--;
-		m_data[m_size] = '\0';
+		data()[m_size] = '\0';
 	}
 
 	void String::remove(size_type index)
 	{
-		erase(index,  1);
-	}
-
-	void String::erase(size_type index, size_type count)
-	{
-		ASSERT(index + count <= m_size);
-		memmove(m_data + index, m_data + index + count, m_size - index - count);
-		m_size -= count;
-		m_data[m_size] = '\0';
+		ASSERT(index < m_size);
+		memcpy(data() + index, data() + index + 1, m_size - index);
+		m_size--;
+		data()[m_size] = '\0';
 	}
 
 	void String::clear()
 	{
+		if (!has_sso())
+		{
+			deallocator(m_storage.general_storage.data);
+			m_storage.sso_storage = SSOStorage();
+			m_has_sso = true;
+		}
 		m_size = 0;
-		m_data[0] = '\0';
+		data()[m_size] = '\0';
 	}
 
-	char String::operator[](size_type index) const
+	bool String::operator==(StringView str) const
 	{
-		ASSERT(index < m_size);
-		return m_data[index];
-	}
-
-	char& String::operator[](size_type index)
-	{
-		ASSERT(index < m_size);
-		return m_data[index];
-	}
-
-	bool String::operator==(const String& other) const
-	{
-		if (m_size != other.m_size)
+		if (size() != str.size())
 			return false;
-		return memcmp(m_data, other.m_data, m_size) == 0;
-	}
-
-	bool String::operator==(StringView other) const
-	{
-		if (m_size != other.size())
-			return false;
-		return memcmp(m_data, other.data(), m_size) == 0;
-	}
-
-	bool String::operator==(const char* other) const
-	{
-		for (size_type i = 0; i <= m_size; i++)
-			if (m_data[i] != other[i])
+		for (size_type i = 0; i < m_size; i++)
+			if (data()[i] != str.data()[i])
 				return false;
 		return true;
 	}
 
-	ErrorOr<void> String::resize(size_type size, char ch)
+	bool String::operator==(const char* cstr) const
 	{
-		if (size < m_size)
+		for (size_type i = 0; i < m_size; i++)
+			if (data()[i] != cstr[i])
+				return false;
+		if (cstr[size()] != '\0')
+			return false;
+		return true;
+	}
+
+	ErrorOr<void> String::resize(size_type new_size, char init_c)
+	{
+		if (m_size == new_size)
+			return {};
+
+		// expanding
+		if (m_size < new_size)
 		{
-			m_data[size] = '\0';
-			m_size = size;
+			TRY(ensure_capacity(new_size));
+			memset(data() + m_size, init_c, new_size - m_size);
+			m_size = new_size;
+			data()[m_size] = '\0';
+			return {};
 		}
-		else if (size > m_size)
-		{
-			TRY(ensure_capacity(size + 1));
-			for (size_type i = m_size; i < size; i++)
-				m_data[i] = ch;
-			m_data[size] = '\0';
-			m_size = size;
-		}
-		m_size = size;
+
+		m_size = new_size;
+		data()[m_size] = '\0';
 		return {};
 	}
 
-	ErrorOr<void> String::reserve(size_type size)
+	ErrorOr<void> String::reserve(size_type new_size)
 	{
-		TRY(ensure_capacity(size));
+		TRY(ensure_capacity(new_size));
 		return {};
 	}
 
 	ErrorOr<void> String::shrink_to_fit()
 	{
-		size_type temp = m_capacity;
-		m_capacity = 0;
-		auto error_or = ensure_capacity(m_size);
-		if (error_or.is_error())
+		if (has_sso())
+			return {};
+
+		if (fits_in_sso())
 		{
-			m_capacity = temp;
-			return error_or;
+			char* data = m_storage.general_storage.data;
+			m_storage.sso_storage = SSOStorage();
+			m_has_sso = true;
+			memcpy(this->data(), data, m_size + 1);
+			deallocator(data);
+			return {};
 		}
+
+		GeneralStorage& storage = m_storage.general_storage;
+		if (storage.capacity == m_size)
+			return {};
+
+		char* new_data = (char*)allocator(m_size + 1);
+		if (new_data == nullptr)
+			return Error::from_errno(ENOMEM);
+
+		memcpy(new_data, storage.data, m_size);
+		deallocator(storage.data);
+
+		storage.capacity = m_size;
+		storage.data = new_data;
+
 		return {};
 	}
 
-	StringView String::sv() const
-	{
-		return StringView(*this);
-	}
-
-	bool String::empty() const
-	{
-		return m_size == 0;
-	}
-
-	String::size_type String::size() const
-	{
-		return m_size;
-	}
-
 	String::size_type String::capacity() const
 	{
-		return m_capacity;
+		if (has_sso())
+			return sso_capacity;
+		return m_storage.general_storage.capacity;
+	}
+
+	char* String::data()
+	{
+		if (has_sso())
+			return m_storage.sso_storage.data;
+		return m_storage.general_storage.data;
 	}
 
 	const char* String::data() const
 	{
-		return m_data;
+		if (has_sso())
+			return m_storage.sso_storage.data;
+		return m_storage.general_storage.data;
 	}
 
-	ErrorOr<void> String::ensure_capacity(size_type size)
+	ErrorOr<void> String::ensure_capacity(size_type new_size)
 	{
-		if (m_capacity >= size)
+		if (m_size >= new_size)
 			return {};
-		size_type new_cap = BAN::Math::max<size_type>(size, m_capacity * 2);
-		void* new_data = BAN::allocator(new_cap);
+		if (has_sso() && fits_in_sso(new_size))
+			return {};
+		
+		char* new_data = (char*)allocator(new_size + 1);
 		if (new_data == nullptr)
 			return Error::from_errno(ENOMEM);
-		if (m_data)
-			memcpy(new_data, m_data, m_size + 1);
-		BAN::deallocator(m_data);
-		m_data = (char*)new_data;
-		m_capacity = new_cap;
+		
+		memcpy(new_data, data(), m_size + 1);
+
+		if (has_sso())
+		{
+			m_storage.general_storage = GeneralStorage();
+			m_has_sso = false;
+		}
+		else
+			deallocator(m_storage.general_storage.data);
+
+		auto& storage = m_storage.general_storage;
+		storage.capacity = new_size;
+		storage.data = new_data;
+
 		return {};
 	}
 
-	ErrorOr<void> String::copy_impl(StringView other)
+	bool String::has_sso() const
 	{
-		TRY(ensure_capacity(other.size() + 1));
-		memcpy(m_data, other.data(), other.size());
-		m_size = other.size();
-		m_data[m_size] = '\0';
-		return {};
-	}
-
-	void String::move_impl(String&& other)
-	{
-		m_data		= other.m_data;
-		m_size		= other.m_size;
-		m_capacity	= other.m_capacity;
-
-		other.m_data = nullptr;
-		other.m_size = 0;
-		other.m_capacity = 0;
+		return m_has_sso;
 	}
 
 }

BAN/BAN/StringView.cpp

@@ -63,9 +63,38 @@ namespace BAN
 
 	ErrorOr<Vector<StringView>> StringView::split(char delim, bool allow_empties)
 	{
-		// FIXME: Won't work while multithreading
-		static char s_delim = delim;
-		return split([](char c){ return c == s_delim; }, allow_empties);
+		size_type count = 0;
+		{
+			size_type start = 0;
+			for (size_type i = 0; i < m_size; i++)
+			{
+				if (m_data[i] == delim)
+				{
+					if (allow_empties || start != i)
+						count++;
+					start = i + 1;
+				}
+			}
+			if (start != m_size)
+				count++;
+		}
+
+		Vector<StringView> result;
+		TRY(result.reserve(count));
+
+		size_type start = 0;
+		for (size_type i = 0; i < m_size; i++)
+		{
+			if (m_data[i] == delim)
+			{
+				if (allow_empties || start != i)
+					TRY(result.push_back(this->substring(start, i - start)));
+				start = i + 1;
+			}
+		}
+		if (start != m_size)
+			TRY(result.push_back(this->substring(start)));
+		return result;
 	}
 
 	ErrorOr<Vector<StringView>> StringView::split(bool(*comp)(char), bool allow_empties)
@@ -116,6 +145,14 @@ namespace BAN
 		return m_data[0];
 	}
 
+	bool StringView::contains(char ch) const
+	{
+		for (size_type i = 0; i < m_size; i++)
+			if (m_data[i] == ch)
+				return true;
+		return false;
+	}
+
 	StringView::size_type StringView::count(char ch) const
 	{
 		size_type result = 0;

BAN/BAN/Time.cpp

@@ -0,0 +1,71 @@
+#include <BAN/Time.h>
+
+namespace BAN
+{
+
+	static constexpr bool is_leap_year(uint64_t year)
+	{
+		if (year % 400 == 0)
+			return true;
+		if (year % 100 == 0)
+			return false;
+		if (year % 4 == 0)
+			return true;
+		return false;
+	}
+
+	static constexpr uint64_t leap_days_since_epoch(const BAN::Time& time)
+	{
+		uint64_t leap_years = 0;
+		for (uint32_t year = 1970; year < time.year; year++)
+			if (is_leap_year(year))
+				leap_years++;
+		if (is_leap_year(time.year) && time.month >= 3)
+			leap_years++;
+		return leap_years;
+	}
+
+	static constexpr uint64_t month_days[] { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
+
+	uint64_t to_unix_time(const BAN::Time& time)
+	{
+		uint64_t years = time.year - 1970;
+		uint64_t days = years * 365 + month_days[time.month - 1] + leap_days_since_epoch(time) + (time.day - 1);
+		uint64_t hours = days * 24 + time.hour;
+		uint64_t minutes = hours * 60 + time.minute;
+		uint64_t seconds = minutes * 60 + time.second;
+		return seconds;
+	}
+
+	BAN::Time from_unix_time(uint64_t unix_time)
+	{		
+		BAN::Time time {};
+
+		time.second = unix_time % 60; unix_time /= 60;
+		time.minute = unix_time % 60; unix_time /= 60;
+		time.hour   = unix_time % 24; unix_time /= 24;
+
+		uint64_t total_days = unix_time;
+
+		time.week_day = (total_days + 4) % 7 + 1;
+
+		time.year = 1970;
+		while (total_days >= 365U + is_leap_year(time.year))
+		{
+			total_days -= 365U + is_leap_year(time.year);
+			time.year++;
+		}
+
+		bool is_leap_day = is_leap_year(time.year) && total_days == month_days[2];
+		bool had_leap_day = is_leap_year(time.year) && total_days > month_days[2];
+
+		for (time.month = 1; time.month < 12; time.month++)
+			if (total_days < month_days[time.month] + (is_leap_day || had_leap_day))
+				break;
+
+		time.day = total_days - month_days[time.month - 1] + !had_leap_day;
+
+		return time;
+	}
+
+}

BAN/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(BAN CXX)
+
+set(BAN_SOURCES
+	BAN/New.cpp
+	BAN/String.cpp
+	BAN/StringView.cpp
+	BAN/Time.cpp
+)
+
+add_custom_target(ban-headers
+	COMMAND ${CMAKE_COMMAND} -E copy_directory_if_different ${CMAKE_CURRENT_SOURCE_DIR}/include/ ${BANAN_INCLUDE}/
+	DEPENDS sysroot
+)
+
+add_library(ban ${BAN_SOURCES})
+add_dependencies(ban headers libc-install)
+
+add_custom_target(ban-install
+	COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_BINARY_DIR}/libban.a ${BANAN_LIB}/
+	DEPENDS ban
+	BYPRODUCTS ${BANAN_LIB}/libban.a
+)

BAN/Makefile

@@ -1,89 +0,0 @@
-DEFAULT_HOST!=../default-host.sh
-HOST?=DEFAULT_HOST
-HOSTARCH!=../target-triplet-to-arch.sh $(HOST)
- 
-CFLAGS?=-O2 -g
-CPPFLAGS?=
-LDFLAGS?=
-LIBS?=
- 
-DESTDIR?=
-PREFIX?=/usr/local
-EXEC_PREFIX?=$(PREFIX)
-INCLUDEDIR?=$(PREFIX)/include
-LIBDIR?=$(EXEC_PREFIX)/lib
- 
-CFLAGS:=$(CFLAGS) -Iinclude -ffreestanding -Wall -Wextra -Werror=return-type
-CPPFLAGS:=$(CPPFLAGS)
-LIBBANK_CFLAGS:=$(CFLAGS) -D__is_kernel -Iinclude -ffreestanding -Wall -Wextra
-LIBBANK_CPPFLAGS:=$(CPPFLAGS) -fno-rtti -fno-exceptions
- 
-ARCHDIR=arch/$(HOSTARCH)
- 
-include $(ARCHDIR)/make.config
- 
-CFLAGS:=$(CFLAGS) $(ARCH_CFLAGS)
-CPPFLAGS:=$(CPPFLAGS) $(ARCH_CPPFLAGS)
-LIBBANK_CFLAGS:=$(LIBBANK_CFLAGS) $(KERNEL_ARCH_CFLAGS)
-LIBBANK_CPPFLAGS:=$(LIBBANK_CPPFLAGS) $(KERNEL_ARCH_CPPFLAGS)
- 
-BUILDDIR=$(abspath build)
- 
-FREEOBJS=			\
-$(ARCH_FREEOBJS)	\
-BAN/Memory.o		\
-BAN/String.o		\
-BAN/StringView.o	\
- 
-HOSTEDOBJS=\
-$(ARCH_HOSTEDOBJS) \
- 
-OBJS=\
-$(FREEOBJS) \
-$(HOSTEDOBJS) \
- 
-LIBBANK_OBJS=$(FREEOBJS:.o=.bank.o)
- 
-BINARIES=libbank.a
- 
-.PHONY: all always clean install install-headers install-libs
-.SUFFIXES: .o .bank.o .cpp .S
- 
-all: $(BINARIES)
- 
-libban.a: always $(OBJS)
-	cd $(BUILDDIR) && $(AR) rcs $@ $(OBJS)
- 
-libbank.a: always $(LIBBANK_OBJS)
-	cd $(BUILDDIR) && $(AR) rcs $@ $(LIBBANK_OBJS)
- 
-.cpp.o:
-	$(CXX) -MD -c $< -o $(BUILDDIR)/$@ $(CFLAGS) $(CPPFLAGS)
- 
-.S.o:
-	$(CXX) -MD -c $< -o $(BUILDDIR)/$@ $(CFLAGS) $(CPPFLAGS)
- 
-.cpp.bank.o:
-	$(CXX) -MD -c $< -o $(BUILDDIR)/$@ $(LIBBANK_CFLAGS) $(LIBBANK_CPPFLAGS)
- 
-.S.bank.o:
-	$(CXX) -MD -c $< -o $(BUILDDIR)/$@ $(LIBBANK_CFLAGS) $(LIBBANK_CPPFLAGS)
- 
-clean:
-	rm -rf $(BUILDDIR)
- 
-always:
-	mkdir -p $(BUILDDIR)/BAN
- 
-install: install-headers install-libs
- 
-install-headers:
-	mkdir -p $(DESTDIR)$(INCLUDEDIR)
-	cp -R --preserve=timestamps include/. $(DESTDIR)$(INCLUDEDIR)/.
- 
-install-libs: $(BINARIES)
-	mkdir -p $(DESTDIR)$(LIBDIR)
-	cp $(BUILDDIR)/$(BINARIES) $(DESTDIR)$(LIBDIR)
- 
--include $(OBJS:.o=.d)
--include $(LIBBANK_OBJS:.o=.d)

BAN/arch/i386/make.config

@@ -1,8 +0,0 @@
-ARCH_CFLAGS=
-ARCH_CPPFLAGS=
-KERNEL_ARCH_CFLAGS=
-KERNEL_ARCH_CPPFLAGS=
- 
-ARCH_FREEOBJS=\
- 
-ARCH_HOSTEDOBJS=\

BAN/arch/x86_64/make.config

@@ -1,8 +0,0 @@
-ARCH_CFLAGS=
-ARCH_CPPFLAGS=
-KERNEL_ARCH_CFLAGS=
-KERNEL_ARCH_CPPFLAGS=
- 
-ARCH_FREEOBJS=\
- 
-ARCH_HOSTEDOBJS=\

BAN/include/BAN/Array.h

@@ -1,6 +1,8 @@
 #pragma once
 
 #include <BAN/Errors.h>
+#include <BAN/Iterators.h>
+#include <BAN/Span.h>
 
 #include <stddef.h>
 
@@ -13,11 +15,18 @@ namespace BAN
 	public:
 		using size_type = decltype(S);
 		using value_type = T;
+		using iterator = IteratorSimple<T, Array>;
+		using const_iterator = ConstIteratorSimple<T, Array>;
 
 	public:
 		Array();
 		Array(const T&);
 
+		iterator begin() { return iterator(m_data); }
+		iterator end() { return iterator(m_data + size()); }
+		const_iterator begin() const { return const_iterator(m_data); }
+		const_iterator end() const { return const_iterator(m_data + size()); }
+
 		const T& operator[](size_type) const;
 		T& operator[](size_type);
 
@@ -26,8 +35,14 @@ namespace BAN
 		const T& front() const;
 		T& front();
 
+		Span<T> span() { return Span(m_data, size()); }
+		const Span<T> span() const { return Span(m_data, size()); }
+
 		constexpr size_type size() const;
 		
+		const T* data() const { return m_data; }
+		T* data() { return m_data; }
+
 	private:
 		T m_data[S];
 	};

BAN/include/BAN/Assert.h

@@ -1,11 +1,33 @@
 #pragma once
 
+#include <BAN/Traits.h>
+
 #if defined(__is_kernel)
 	#include <kernel/Panic.h>
-	#define ASSERT(cond) do { if (!(cond)) Kernel::panic("ASSERT("#cond") failed"); } while(false)
+
+	#define ASSERT(cond)									\
+		do {												\
+			if (!(cond))									\
+				Kernel::panic("ASSERT(" #cond ") failed");	\
+		} while (false)
+
+	#define __ASSERT_BIN_OP(lhs, rhs, name, op)														\
+		do {																						\
+			auto&& _lhs = lhs;																		\
+			auto&& _rhs = rhs;																		\
+			if (!(_lhs op _rhs))																	\
+					Kernel::panic(name "(" #lhs ", " #rhs ") ({} " #op " {}) failed", _lhs, _rhs);	\
+		} while (false)
+
+	#define ASSERT_LT(lhs, rhs)		__ASSERT_BIN_OP(lhs, rhs, "ASSERT_LT",	<)
+	#define ASSERT_LTE(lhs, rhs)	__ASSERT_BIN_OP(lhs, rhs, "ASSERT_LTE",	<=)
+	#define ASSERT_GT(lhs, rhs)		__ASSERT_BIN_OP(lhs, rhs, "ASSERT_GT",	>)
+	#define ASSERT_GTE(lhs, rhs)	__ASSERT_BIN_OP(lhs, rhs, "ASSERT_GTE",	>=)
+	#define ASSERT_EQ(lhs, rhs)		__ASSERT_BIN_OP(lhs, rhs, "ASSERT_EQ",	==)
+	#define ASSERT_NEQ(lhs, rhs)	__ASSERT_BIN_OP(lhs, rhs, "ASSERT_NEQ",	!=)
 	#define ASSERT_NOT_REACHED() Kernel::panic("ASSERT_NOT_REACHED() failed")
 #else
 	#include <assert.h>
 	#define ASSERT(cond) assert((cond) && "ASSERT("#cond") failed")
-	#define ASSERT_NOT_REACHED() assert(false && "ASSERT_NOT_REACHED() failed")
+	#define ASSERT_NOT_REACHED() do { assert(false && "ASSERT_NOT_REACHED() failed"); __builtin_unreachable(); } while (false)
 #endif

BAN/include/BAN/ByteSpan.h

@@ -0,0 +1,140 @@
+#pragma once
+
+#include <BAN/Span.h>
+
+namespace BAN
+{
+
+	template<bool CONST>
+	class ByteSpanGeneral
+	{
+	public:
+		using value_type = maybe_const_t<CONST, uint8_t>;
+		using size_type = size_t;
+
+	public:
+		ByteSpanGeneral() = default;
+		ByteSpanGeneral(value_type* data, size_type size)
+			: m_data(data)
+			, m_size(size)
+		{ }
+
+		ByteSpanGeneral(ByteSpanGeneral& other)
+			: m_data(other.data())
+			, m_size(other.size())
+		{ }
+		template<bool C2>
+		ByteSpanGeneral(const ByteSpanGeneral<C2>& other) requires(CONST)
+			: m_data(other.data())
+			, m_size(other.size())
+		{ }
+		ByteSpanGeneral(Span<uint8_t> other)
+			: m_data(other.data())
+			, m_size(other.size())
+		{ }
+		ByteSpanGeneral(const Span<const uint8_t>& other) requires(CONST)
+			: m_data(other.data())
+			, m_size(other.size())
+		{ }
+
+		ByteSpanGeneral& operator=(ByteSpanGeneral other)
+		{
+			m_data = other.data();
+			m_size = other.size();
+			return *this;
+		}
+		template<bool C2>
+		ByteSpanGeneral& operator=(const ByteSpanGeneral<C2>& other) requires(CONST)
+		{
+			m_data = other.data();
+			m_size = other.size();
+			return *this;
+		}
+		ByteSpanGeneral& operator=(Span<uint8_t> other)
+		{
+			m_data = other.data();
+			m_size = other.size();
+			return *this;
+		}
+		ByteSpanGeneral& operator=(const Span<const uint8_t>& other) requires(CONST)
+		{
+			m_data = other.data();
+			m_size = other.size();
+			return *this;
+		}
+
+		template<typename S>
+		requires(CONST || !is_const_v<S>)
+		static ByteSpanGeneral from(S& value)
+		{
+			return ByteSpanGeneral(reinterpret_cast<value_type*>(&value), sizeof(S));
+		}
+
+		template<typename S>
+		requires(!CONST && !is_const_v<S>)
+		S& as()
+		{
+			ASSERT(m_data);
+			ASSERT(m_size >= sizeof(S));
+			return *reinterpret_cast<S*>(m_data);
+		}
+
+		template<typename S>
+		requires(is_const_v<S>)
+		S& as() const
+		{
+			ASSERT(m_data);
+			ASSERT(m_size >= sizeof(S));
+			return *reinterpret_cast<S*>(m_data);
+		}
+
+		template<typename S>
+		requires(!CONST && !is_const_v<S>)
+		Span<S> as_span()
+		{
+			ASSERT(m_data);
+			return Span<S>(reinterpret_cast<S*>(m_data), m_size / sizeof(S));
+		}
+
+		template<typename S>
+		const Span<S> as_span() const
+		{
+			ASSERT(m_data);
+			return Span<S>(reinterpret_cast<S*>(m_data), m_size / sizeof(S));
+		}
+
+		ByteSpanGeneral slice(size_type offset, size_type length = size_type(-1))
+		{
+			ASSERT(m_data);
+			ASSERT(m_size >= offset);
+			if (length == size_type(-1))
+				length = m_size - offset;
+			ASSERT(m_size >= offset + length);
+			return ByteSpanGeneral(m_data + offset, length);
+		}
+
+		value_type& operator[](size_type offset)
+		{
+			ASSERT(offset < m_size);
+			return m_data[offset];
+		}
+		const value_type& operator[](size_type offset) const
+		{
+			ASSERT(offset < m_size);
+			return m_data[offset];
+		}
+
+		value_type* data() { return m_data; }
+		const value_type* data() const { return m_data; } 
+
+		size_type size() const { return m_size; }
+
+	private:
+		value_type* m_data { nullptr };
+		size_type m_size { 0 };
+	};
+
+	using ByteSpan = ByteSpanGeneral<false>;
+	using ConstByteSpan = ByteSpanGeneral<true>;
+
+}

BAN/include/BAN/CircularQueue.h

@@ -0,0 +1,113 @@
+#pragma once
+
+#include <BAN/Assert.h>
+
+#include <stdint.h>
+#include <stddef.h>
+
+namespace BAN
+{
+
+	template<typename T, size_t S>
+	class CircularQueue
+	{
+	public:
+		using size_type = size_t;
+		using value_type = T;
+
+	public:
+		CircularQueue() = default;
+		~CircularQueue();
+
+		void push(const T&);
+		void push(T&&);
+		template<typename... Args>
+		void emplace(Args&&... args);
+
+		void pop();
+
+		const T& front() const;
+		T& front();
+
+		size_type size() const { return m_size; }
+		bool empty() const { return size() == 0; }
+		bool full() const { return size() == capacity(); }
+		
+		static constexpr size_type capacity() { return S; }
+
+	private:
+		T* element_at(size_type);
+		const T* element_at(size_type) const;
+
+	private:
+		alignas(T) uint8_t m_storage[sizeof(T) * capacity()];
+		size_type m_first { 0 };
+		size_type m_size { 0 };
+	};
+
+	template<typename T, size_t S>
+	CircularQueue<T, S>::~CircularQueue()
+	{
+		for (size_type i = 0; i < m_size; i++)
+			element_at((m_first + i) % capacity())->~T();
+	}
+
+	template<typename T, size_t S>
+	void CircularQueue<T, S>::push(const T& value)
+	{
+		emplace(BAN::move(T(value)));
+	}
+
+	template<typename T, size_t S>
+	void CircularQueue<T, S>::push(T&& value)
+	{
+		emplace(BAN::move(value));
+	}
+
+	template<typename T, size_t S>
+	template<typename... Args>
+	void CircularQueue<T, S>::emplace(Args&&... args)
+	{
+		ASSERT(!full());
+		new (element_at(((m_first + m_size) % capacity()))) T(BAN::forward<Args>(args)...);
+		m_size++;
+	}
+
+	template<typename T, size_t S>
+	void CircularQueue<T, S>::pop()
+	{
+		ASSERT(!empty());
+		element_at(m_first)->~T();
+		m_first = (m_first + 1) % capacity();
+		m_size--;
+	}
+
+	template<typename T, size_t S>
+	const T& CircularQueue<T, S>::front() const
+	{
+		ASSERT(!empty());
+		return *element_at(m_first);
+	}
+
+	template<typename T, size_t S>
+	T& CircularQueue<T, S>::front()
+	{
+		ASSERT(!empty());
+		return *element_at(m_first);
+	}
+
+	template<typename T, size_t S>
+	const T* CircularQueue<T, S>::element_at(size_type index) const
+	{
+		ASSERT(index < capacity());
+		return (const T*)(m_storage + index * sizeof(T));
+	}
+
+	template<typename T, size_t S>
+	T* CircularQueue<T, S>::element_at(size_type index)
+	{
+		ASSERT(index < capacity());
+		return (T*)(m_storage + index * sizeof(T));
+	}
+
+}

BAN/include/BAN/Endianness.h

@@ -0,0 +1,80 @@
+#pragma once
+
+#include <BAN/Traits.h>
+
+#include <stddef.h>
+
+namespace BAN
+{
+
+	template<integral T>
+	constexpr T swap_endianness(T value)
+	{
+		if constexpr(sizeof(T) == 1)
+			return value;
+		if constexpr(sizeof(T) == 2)
+			return (((value >> 8) & 0xFF) << 0)
+				 | (((value >> 0) & 0xFF) << 8);
+		if constexpr(sizeof(T) == 4)
+			return (((value >> 24) & 0xFF) <<  0)
+				 | (((value >> 16) & 0xFF) <<  8)
+				 | (((value >>  8) & 0xFF) << 16)
+				 | (((value >>  0) & 0xFF) << 24);
+		if constexpr(sizeof(T) == 8)
+			return (((value >> 56) & 0xFF) <<  0)
+				 | (((value >> 48) & 0xFF) <<  8)
+				 | (((value >> 40) & 0xFF) << 16)
+				 | (((value >> 32) & 0xFF) << 24)
+				 | (((value >> 24) & 0xFF) << 32)
+				 | (((value >> 16) & 0xFF) << 40)
+				 | (((value >>  8) & 0xFF) << 48)
+				 | (((value >>  0) & 0xFF) << 56);
+		T result { 0 };
+		for (size_t i = 0; i < sizeof(T); i++)
+			result |= ((value >> (i * 8)) & 0xFF) << ((sizeof(T) - i - 1) * 8);
+		return result;
+	}
+
+	template<integral T>
+	constexpr T host_to_little_endian(T value)
+	{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+		return value;
+#else
+		return swap_endianness(value);
+#endif
+	}
+
+	template<integral T>
+	constexpr T host_to_big_endian(T value)
+	{
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+		return value;
+#else
+		return swap_endianness(value);
+#endif
+	}
+
+	template<integral T>
+	struct LittleEndian
+	{
+		constexpr operator T() const
+		{
+			return host_to_little_endian(raw);
+		}
+	private:
+		T raw;
+	};
+
+	template<integral T>
+	struct BigEndian
+	{
+		constexpr operator T() const
+		{
+			return host_to_big_endian(raw);
+		}
+	private:
+		T raw;
+	};
+
+}

BAN/include/BAN/Errors.h

@@ -1,62 +1,76 @@
 #pragma once
 
 #include <BAN/Formatter.h>
+#include <BAN/StringView.h>
 #include <BAN/Variant.h>
 
 #include <errno.h>
 #include <string.h>
 
-#if defined(__is_kernel)
+#ifdef __is_kernel
 	#include <kernel/Panic.h>
-	#define MUST(expr)	({ auto e = expr; if (e.is_error()) Kernel::panic("{}", e.error()); e.release_value(); })
+	#include <kernel/Errors.h>
+	#define MUST(expr)		 ({ auto&& e = expr; if (e.is_error()) Kernel::panic("{}", e.error()); e.release_value(); })
+	#define MUST_REF(expr)	*({ auto&& e = expr; if (e.is_error()) Kernel::panic("{}", e.error()); &e.release_value(); })
 #else
-	#define MUST(expr)	({ auto e = expr; assert(!e.is_error()); e.release_value(); })
+	#include <assert.h>
+	#define MUST(expr)		 ({ auto&& e = expr; assert(!e.is_error()); e.release_value(); })
+	#define MUST_REF(expr)	*({ auto&& e = expr; assert(!e.is_error()); &e.release_value(); })
 #endif
 
-#define TRY(expr) ({ auto e = expr; if (e.is_error()) return e.release_error(); e.release_value(); })
+#define TRY(expr)		 ({ auto&& e = expr; if (e.is_error()) return e.release_error(); e.release_value(); })
+#define TRY_REF(expr)	*({ auto&& e = expr; if (e.is_error()) return e.release_error(); &e.release_value(); })
 
 namespace BAN
 {
 
 	class Error
 	{
+#ifdef __is_kernel
+	private:
+		static constexpr uint64_t kernel_error_mask = uint64_t(1) << 63;
+#endif
+
 	public:
-		static Error from_c_string(const char* message)
+#ifdef __is_kernel
+		static Error from_error_code(Kernel::ErrorCode error)
 		{
-			Error result;
-			strncpy(result.m_message, message, sizeof(Error::m_message));
-			result.m_message[sizeof(Error::m_message) - 1] = '\0';
-			result.m_error_code = 0xFF;
-			return result;
-		}
-		template<typename... Args>
-		static Error from_format(const char* format, Args&&... args)
-		{
-			char buffer[sizeof(Error::m_message)] {};
-			size_t index = 0;
-			auto putc = [&](char ch)
-			{
-				if (index < sizeof(buffer) - 1)
-					buffer[index++] = ch;
-			};
-			Formatter::print(putc, format, forward<Args>(args)...);
-			return from_c_string(buffer);
+			return Error((uint64_t)error | kernel_error_mask);
 		}
+#endif
 		static Error from_errno(int error)
 		{
-			Error result;
-			strncpy(result.m_message, strerror(error), sizeof(Error::m_message));
-			result.m_message[sizeof(Error::m_message) - 1] = '\0';
-			result.m_error_code = error;
-			return result;
+			return Error(error);
 		}
 
-		uint8_t get_error_code() const { return m_error_code; }
-		const char* get_message() const { return m_message; }
+#ifdef __is_kernel
+		Kernel::ErrorCode kernel_error() const
+		{
+			return (Kernel::ErrorCode)(m_error_code & ~kernel_error_mask);
+		}
+
+		bool is_kernel_error() const
+		{
+			return m_error_code & kernel_error_mask;
+		}
+#endif
+
+		uint64_t get_error_code() const { return m_error_code; }
+		BAN::StringView get_message() const
+		{
+#ifdef __is_kernel
+			if (m_error_code & kernel_error_mask)
+				return Kernel::error_string(kernel_error());
+#endif
+			return strerror(m_error_code);
+		}
 
 	private:
-		char m_message[128];
-		uint8_t m_error_code;
+		Error(uint64_t error)
+			: m_error_code(error)
+		{}
+
+		uint64_t m_error_code;
 	};
 
 	template<typename T>
@@ -76,19 +90,46 @@ namespace BAN
 			: m_data(move(error))
 		{}
 
-		bool is_error() const			{ return m_data.template is<Error>(); }
+		bool is_error() const			{ return m_data.template has<Error>(); }
 		const Error& error() const		{ return m_data.template get<Error>(); }
 		Error& error()					{ return m_data.template get<Error>(); }
 		const T& value() const			{ return m_data.template get<T>(); }
 		T& value()						{ return m_data.template get<T>(); }
 
-		Error release_error()				{ return move(error()); m_data.clear(); }
+		Error release_error()			{ return move(error()); m_data.clear(); }
 		T release_value()				{ return move(value()); m_data.clear(); }
 
 	private:
 		Variant<Error, T> m_data;
 	};
 
+	template<lvalue_reference T>
+	class [[nodiscard]] ErrorOr<T>
+	{
+	public:
+		ErrorOr(T value)
+		{
+			m_data.template set<T>(value);
+		}
+		ErrorOr(Error&& error)
+			: m_data(move(error))
+		{ }
+		ErrorOr(const Error& error)
+			: m_data(error)
+		{ }
+
+		bool is_error() const			{ return m_data.template has<Error>(); }
+		Error& error()					{ return m_data.template get<Error>(); }
+		const Error& error() const		{ return m_data.template get<Error>(); }
+		T value()						{ return m_data.template get<T>(); }
+
+		Error release_error()			{ return move(error()); m_data.clear(); }
+		T release_value()				{ return value(); m_data.clear(); }
+
+	private:
+		Variant<Error, T> m_data;
+	};
+
 	template<>
 	class [[nodiscard]] ErrorOr<void>
 	{
@@ -102,12 +143,12 @@ namespace BAN
 		const Error& error() const		{ return m_data; }
 		void value()					{ }
 
-		Error release_error()			{ return move(m_data); m_data = Error(); }
-		void release_value()			{ m_data = Error(); }
+		Error release_error()			{ return move(m_data); }
+		void release_value()			{ }
 
 	private:
-		Error m_data;
-		bool m_has_error = false;
+		Error m_data { Error::from_errno(0) };
+		bool m_has_error { false };
 	};
 
 }
@@ -115,11 +156,8 @@ namespace BAN
 namespace BAN::Formatter
 {
 	template<typename F>
-	void print_argument(F putc, const Error& error, const ValueFormat&)
+	void print_argument(F putc, const Error& error, const ValueFormat& format)
 	{
-		if (error.get_error_code() == 0xFF)
-			print(putc, error.get_message());
-		else
-			print(putc, "{} ({})", error.get_message(), error.get_error_code());
+		print_argument(putc, error.get_message(), format);
 	}
 }

BAN/include/BAN/Formatter.h

@@ -28,7 +28,6 @@ namespace BAN::Formatter
 		static size_t parse_format_and_print_argument(F putc, const char* format, T&& arg);
 	}
 
-
 	/*
 
 		IMPLEMENTATION
@@ -243,10 +242,7 @@ namespace BAN::Formatter
 
 	template<typename F> void print_argument(F putc, char			value, const ValueFormat&)	{ putc(value); }
 	template<typename F> void print_argument(F putc, bool			value, const ValueFormat&)	{ print(putc, value ? "true" : "false"); }
-	template<typename F> void print_argument(F putc, const char*	value, const ValueFormat&)	{ print(putc, value);}
-	
-	//template<typename F> void print_argument(F putc, signed char			value, const ValueFormat& format)	{ detail::print_integer(putc, value, format); }
-	//template<typename F> void print_argument(F putc, unsigned char			value, const ValueFormat& format)	{ detail::print_integer(putc, value, format); }
-	//template<typename F, typename T> void print_argument(F putc, T*			value, const ValueFormat& format)	{ detail::print_pointer(putc, (void*)value, format); }
+	template<typename F> void print_argument(F putc, const char*	value, const ValueFormat&)	{ print(putc, value); }
+	template<typename F> void print_argument(F putc, char*			value, const ValueFormat&)	{ print(putc, value); }
 
 }

BAN/include/BAN/ForwardList.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <BAN/Traits.h>
 #include <stddef.h>
 
 namespace BAN
@@ -14,5 +15,6 @@ namespace BAN
 	class StringView;
 	template<typename> class Vector;
 	template<typename> class LinkedList;
+	template<typename... Ts> requires (!is_const_v<Ts> && ...) class Variant;
 
 }

BAN/include/BAN/Function.h

@@ -2,7 +2,7 @@
 
 #include <BAN/Errors.h>
 #include <BAN/Move.h>
-#include <BAN/Memory.h>
+#include <BAN/New.h>
 
 namespace BAN
 {
@@ -43,10 +43,10 @@ namespace BAN
 			clear();
 		}
 
-		Ret operator()(Args... args)
+		Ret operator()(Args... args) const
 		{
 			ASSERT(*this);
-			return reinterpret_cast<CallableBase*>(m_storage)->call(forward<Args>(args)...);
+			return reinterpret_cast<const CallableBase*>(m_storage)->call(forward<Args>(args)...);
 		}
 
 		operator bool() const
@@ -70,7 +70,7 @@ namespace BAN
 		struct CallableBase
 		{
 			virtual ~CallableBase() {}
-			virtual Ret call(Args...) = 0;
+			virtual Ret call(Args...) const = 0;
 		};
 
 		struct CallablePointer : public CallableBase
@@ -79,7 +79,7 @@ namespace BAN
 				: m_function(function)
 			{ }
 
-			virtual Ret call(Args... args) override
+			virtual Ret call(Args... args) const override
 			{
 				return m_function(forward<Args>(args)...);
 			}
@@ -96,7 +96,7 @@ namespace BAN
 				, m_function(function)
 			{ }
 
-			virtual Ret call(Args... args) override
+			virtual Ret call(Args... args) const override
 			{
 				return (m_owner->*m_function)(forward<Args>(args)...);
 			}
@@ -114,7 +114,7 @@ namespace BAN
 				, m_function(function)
 			{ }
 
-			virtual Ret call(Args... args) override
+			virtual Ret call(Args... args) const override
 			{
 				return (m_owner->*m_function)(forward<Args>(args)...);
 			}
@@ -131,7 +131,7 @@ namespace BAN
 				: m_lambda(lambda)
 			{ }
 
-			virtual Ret call(Args... args) override
+			virtual Ret call(Args... args) const override
 			{
 				return m_lambda(forward<Args>(args)...);
 			}
@@ -141,7 +141,7 @@ namespace BAN
 		};
 
 	private:
-		static constexpr size_t m_size = sizeof(void*) * 4;
+		static constexpr size_t m_size = sizeof(void*) * 5;
 		alignas(CallableBase) uint8_t m_storage[m_size] { 0 };
 	};
 

BAN/include/BAN/HashMap.h

@@ -7,13 +7,31 @@
 namespace BAN
 {
 
+	template<typename Container>
+	class HashMapIterator;
+
 	template<typename Key, typename T, typename HASH = BAN::hash<Key>>
 	class HashMap
 	{
+	public:
+		struct Entry
+		{
+			template<typename... Args>
+			Entry(const Key& key, Args&&... args)
+				: key(key)
+				, value(forward<Args>(args)...)
+			{}
+
+			Key key;
+			T value;
+		};
+
 	public:
 		using size_type = size_t;
 		using key_type = Key;
 		using value_type = T;
+		using iterator = IteratorDouble<Entry, Vector, LinkedList, HashMap>;
+		using const_iterator = ConstIteratorDouble<Entry, Vector, LinkedList, HashMap>;
 
 	public:
 		HashMap() = default;
@@ -29,6 +47,11 @@ namespace BAN
 		template<typename... Args>
 		ErrorOr<void> emplace(const Key&, Args&&...);
 
+		iterator begin() { return iterator(m_buckets.end(), m_buckets.begin()); }
+		iterator end()   { return iterator(m_buckets.end(), m_buckets.end()); }
+		const_iterator begin() const { return const_iterator(m_buckets.end(), m_buckets.begin()); }
+		const_iterator end() const   { return const_iterator(m_buckets.end(), m_buckets.end()); }
+
 		ErrorOr<void> reserve(size_type);
 
 		void remove(const Key&);
@@ -42,19 +65,6 @@ namespace BAN
 		bool empty() const;
 		size_type size() const;
 
-	private:
-		struct Entry
-		{
-			template<typename... Args>
-			Entry(const Key& key, Args&&... args)
-				: key(key)
-				, value(forward<Args>(args)...)
-			{}
-
-			Key key;
-			T value;
-		};
-
 	private:
 		ErrorOr<void> rebucket(size_type);
 		LinkedList<Entry>& get_bucket(const Key&);
@@ -63,6 +73,8 @@ namespace BAN
 	private:
 		Vector<LinkedList<Entry>> m_buckets;
 		size_type m_size = 0;
+
+		friend iterator;
 	};
 
 	template<typename Key, typename T, typename HASH>

BAN/include/BAN/HashSet.h

@@ -85,8 +85,6 @@ namespace BAN
 		friend class HashSet<T, HASH>;
 	};
 
-
-
 	template<typename T, typename HASH>
 	HashSet<T, HASH>::HashSet(const HashSet<T, HASH>& other)
 		: m_buckets(other.m_buckets)
@@ -231,8 +229,6 @@ namespace BAN
 		return m_buckets[index];
 	}
 
-
-
 	template<typename T, typename HASH>
 	HashSetIterator<T, HASH>& HashSetIterator<T, HASH>::operator++()
 	{

BAN/include/BAN/Iteration.h

@@ -0,0 +1,12 @@
+#pragma once
+
+namespace BAN
+{
+
+	enum class Iteration
+	{
+		Continue,
+		Break
+	};
+
+}

BAN/include/BAN/Iterators.h

@@ -0,0 +1,229 @@
+#pragma once
+
+#include <BAN/Assert.h>
+
+namespace BAN
+{
+
+	template<typename T, typename Container, bool CONST>
+	class IteratorSimpleGeneral
+	{
+	public:
+		IteratorSimpleGeneral() = default;
+		template<bool CONST2, typename = enable_if_t<CONST2 == CONST || CONST>>
+		IteratorSimpleGeneral(const IteratorSimpleGeneral<T, Container, CONST2>& other)
+			: m_pointer(other.m_pointer)
+		{
+		}
+
+		const T& operator*() const
+		{
+			ASSERT(m_pointer);
+			return *m_pointer;
+		}
+		template<bool CONST2 = CONST>
+		enable_if_t<!CONST2, T&> operator*()
+		{
+			ASSERT(m_pointer);
+			return *m_pointer;
+		}
+
+		const T* operator->() const
+		{
+			ASSERT(m_pointer);
+			return m_pointer;
+		}
+		template<bool CONST2 = CONST>
+		enable_if_t<!CONST2, T*> operator->()
+		{
+			ASSERT(m_pointer);
+			return m_pointer;
+		}
+
+		IteratorSimpleGeneral& operator++()
+		{
+			ASSERT(m_pointer);
+			++m_pointer;
+			return *this;
+		}
+		IteratorSimpleGeneral operator++(int)
+		{
+			auto temp = *this;
+			++(*this);
+			return temp;
+		}
+
+		IteratorSimpleGeneral& operator--()
+		{
+			ASSERT(m_pointer);
+			return --m_pointer;
+		}
+		IteratorSimpleGeneral operator--(int)
+		{
+			auto temp = *this;
+			--(*this);
+			return temp;
+		}
+
+		bool operator==(const IteratorSimpleGeneral& other) const
+		{
+			return m_pointer == other.m_pointer;
+		}
+		bool operator!=(const IteratorSimpleGeneral& other) const
+		{
+			return !(*this == other);
+		}
+
+		operator bool() const
+		{
+			return m_pointer;
+		}
+
+	private:
+		IteratorSimpleGeneral(maybe_const_t<CONST, T>* pointer)
+			: m_pointer(pointer)
+		{
+		}
+
+	private:
+		maybe_const_t<CONST, T>* m_pointer = nullptr;
+
+		friend IteratorSimpleGeneral<T, Container, !CONST>;
+		friend Container;
+	};
+
+	template<typename T, template<typename> typename OuterContainer, template<typename> typename InnerContainer, typename Container, bool CONST>
+	class IteratorDoubleGeneral
+	{
+	public:
+		using Inner = InnerContainer<T>;
+		using Outer = OuterContainer<Inner>;
+
+		using InnerIterator = either_or_t<CONST, typename Inner::const_iterator, typename Inner::iterator>;
+		using OuterIterator = either_or_t<CONST, typename Outer::const_iterator, typename Outer::iterator>;
+
+	public:
+		IteratorDoubleGeneral() = default;
+		template<bool CONST2, typename = enable_if_t<CONST2 == CONST || CONST>>
+		IteratorDoubleGeneral(const IteratorDoubleGeneral<T, OuterContainer, InnerContainer, Container, CONST2>& other)
+			: m_outer_end(other.m_outer_end)
+			, m_outer_current(other.m_outer_current)
+			, m_inner_current(other.m_inner_current)
+		{
+		}
+
+		const T& operator*() const
+		{
+			ASSERT(*this);
+			ASSERT(m_outer_current != m_outer_end);
+			ASSERT(m_inner_current);
+			return m_inner_current.operator*();
+		}
+		template<bool CONST2 = CONST>
+		enable_if_t<!CONST2, T&> operator*()
+		{
+			ASSERT(*this);
+			ASSERT(m_outer_current != m_outer_end);
+			ASSERT(m_inner_current);
+			return m_inner_current.operator*();
+		}
+
+		const T* operator->() const
+		{
+			ASSERT(*this);
+			ASSERT(m_outer_current != m_outer_end);
+			ASSERT(m_inner_current);
+			return m_inner_current.operator->();
+		}
+		template<bool CONST2 = CONST>
+		enable_if_t<!CONST2, T*> operator->()
+		{
+			ASSERT(*this);
+			ASSERT(m_outer_current != m_outer_end);
+			ASSERT(m_inner_current);
+			return m_inner_current.operator->();
+		}
+
+		IteratorDoubleGeneral& operator++()
+		{
+			ASSERT(*this);
+			ASSERT(m_outer_current != m_outer_end);
+			ASSERT(m_inner_current);
+			m_inner_current++;
+			find_valid_or_end();
+			return *this;
+		}
+		IteratorDoubleGeneral operator++(int)
+		{
+			auto temp = *this;
+			++(*this);
+			return temp;
+		}
+
+		bool operator==(const IteratorDoubleGeneral& other) const
+		{
+			if (!*this || !other)
+				return false;
+			if (m_outer_end != other.m_outer_end)
+				return false;
+			if (m_outer_current != other.m_outer_current)
+				return false;
+			if (m_outer_current == m_outer_end)
+				return true;
+			return m_inner_current == other.m_inner_current;
+		}
+		bool operator!=(const IteratorDoubleGeneral& other) const
+		{
+			return !(*this == other);
+		}
+
+		operator bool() const
+		{
+			return m_outer_end && m_outer_current;
+		}
+
+	private:
+		IteratorDoubleGeneral(const OuterIterator& outer_end, const OuterIterator& outer_current)
+			: m_outer_end(outer_end)
+			, m_outer_current(outer_current)
+		{
+			if (outer_current != outer_end)
+			{
+				m_inner_current = m_outer_current->begin();
+				find_valid_or_end();
+			}
+		}
+
+		void find_valid_or_end()
+		{
+			while (m_inner_current == m_outer_current->end())
+			{
+				m_outer_current++;
+				if (m_outer_current == m_outer_end)
+					break;
+				m_inner_current = m_outer_current->begin();
+			}
+		}
+
+	private:
+		OuterIterator m_outer_end;
+		OuterIterator m_outer_current;
+		InnerIterator m_inner_current;
+
+		friend class IteratorDoubleGeneral<T, OuterContainer, InnerContainer, Container, !CONST>;
+		friend Container;
+	};
+
+	template<typename T, typename Container>
+	using IteratorSimple = IteratorSimpleGeneral<T, Container, false>;
+
+	template<typename T, typename Container>
+	using ConstIteratorSimple = IteratorSimpleGeneral<T, Container, true>;
+
+	template<typename T, template<typename> typename OuterContainer, template<typename> typename InnerContainer, typename Container>
+	using IteratorDouble = IteratorDoubleGeneral<T, OuterContainer, InnerContainer, Container, false>;
+
+	template<typename T, template<typename> typename OuterContainer, template<typename> typename InnerContainer, typename Container>
+	using ConstIteratorDouble = IteratorDoubleGeneral<T, OuterContainer, InnerContainer, Container, true>;
+
+}

BAN/include/BAN/LinkedList.h

@@ -1,8 +1,8 @@
 #pragma once
 
 #include <BAN/Errors.h>
-#include <BAN/Memory.h>
 #include <BAN/Move.h>
+#include <BAN/New.h>
 
 namespace BAN
 {
@@ -38,7 +38,7 @@ namespace BAN
 		ErrorOr<void> emplace(iterator, Args&&...);
 
 		void pop_back();
-		void remove(iterator);
+		iterator remove(iterator);
 		void clear();
 
 		iterator begin()				{ return iterator(m_data, empty()); }
@@ -114,8 +114,6 @@ namespace BAN
 		friend class LinkedListIterator<T, !CONST>;
 	};
 
-
-
 	template<typename T>
 	LinkedList<T>& LinkedList<T>::operator=(const LinkedList<T>& other)
 	{
@@ -197,11 +195,11 @@ namespace BAN
 	template<typename T>
 	void LinkedList<T>::pop_back()
 	{
-		return remove(m_last);
+		remove(iterator(m_last, false));
 	}
 
 	template<typename T>
-	void LinkedList<T>::remove(iterator iter)
+	LinkedList<T>::iterator LinkedList<T>::remove(iterator iter)
 	{
 		ASSERT(!empty() && iter);
 		Node* node = iter.m_current;
@@ -212,6 +210,7 @@ namespace BAN
 		(prev ? prev->next : m_data) = next;
 		(next ? next->prev : m_last) = prev;
 		m_size--;
+		return next ? iterator(next, false) : iterator(m_last, true);
 	}
 
 	template<typename T>
@@ -292,8 +291,6 @@ namespace BAN
 		return node;
 	}
 
-
-
 	template<typename T, bool CONST>
 	template<bool C>
 	LinkedListIterator<T, CONST>::LinkedListIterator(const LinkedListIterator<T, C>& other, enable_if_t<C == CONST || !C>*)

BAN/include/BAN/Math.h

@@ -52,20 +52,53 @@ namespace BAN::Math
 	}
 
 	template<integral T>
-	inline constexpr T little_endian_to_host(const uint8_t* bytes)
+	inline constexpr bool is_power_of_two(T value)
 	{
-		T result = 0;
-		for (size_t i = 0; i < sizeof(T); i++)
-			result |= (T)bytes[i] << (i * 8);
+		if (value == 0)
+			return false;
+		return (value & (value - 1)) == 0;
+	}
+
+	template<floating_point T>
+	inline constexpr T log2(T value)
+	{
+		T result;
+		asm volatile("fyl2x" : "=t"(result) : "0"(value), "u"((T)1.0) : "st(1)");
 		return result;
 	}
 
-	template<integral T>
-	inline constexpr T big_endian_to_host(const uint8_t* bytes)
+	template<floating_point T>
+	inline constexpr T log10(T value)
 	{
-		T result = 0;
-		for (size_t i = 0; i < sizeof(T); i++)
-			result |= (T)bytes[i] << (8 * (sizeof(T) - i - 1));
+		constexpr T INV_LOG_2_10 = 0.3010299956639811952137388947244930267681898814621085413104274611;
+		T result;
+		asm volatile("fyl2x" : "=t"(result) : "0"(value), "u"(INV_LOG_2_10) : "st(1)");
+		return result;
+	}
+
+	template<floating_point T>
+	inline constexpr T log(T value, T base)
+	{
+		return log2(value) / log2(base);
+	}
+
+	template<floating_point T>
+	inline constexpr T pow(T base, T exp)
+	{
+		T result;
+		asm volatile(
+			"fyl2x;"
+			"fld1;"
+			"fld %%st(1);"
+			"fprem;"
+			"f2xm1;"
+			"faddp;"
+			"fscale;"
+			"fxch %%st(1);"
+			"fstp %%st;"
+			: "=t"(result)
+			: "0"(base), "u"(exp)
+		);
 		return result;
 	}
 

BAN/include/BAN/Move.h

@@ -2,6 +2,8 @@
 
 #include <BAN/Traits.h>
 
+#include <stddef.h>
+
 namespace BAN
 {
 
@@ -25,3 +27,6 @@ namespace BAN
 	}
 
 }
+
+inline void* operator new(size_t, void* addr)	{ return addr; }
+inline void* operator new[](size_t, void* addr)	{ return addr; }

BAN/include/BAN/New.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#if defined(__is_kernel)
+	#include <kernel/Memory/kmalloc.h>
+#else
+	#include <stdlib.h>
+#endif
+
+namespace BAN
+{
+	#if defined(__is_kernel)
+		static constexpr void*(&allocator)(size_t) = kmalloc;
+		static constexpr void(&deallocator)(void*) = kfree;
+	#else
+		static constexpr void*(&allocator)(size_t) = malloc;
+		static constexpr void(&deallocator)(void*) = free;
+	#endif
+}

BAN/include/BAN/Optional.h

@@ -0,0 +1,195 @@
+#pragma once
+
+#include <BAN/Assert.h>
+#include <BAN/Move.h>
+
+#include <stdint.h>
+
+namespace BAN
+{
+
+	template<typename T>
+	class Optional
+	{
+	public:
+		Optional();
+		Optional(Optional&&);
+		Optional(const Optional&);
+		Optional(const T&);
+		Optional(T&&);
+		template<typename... Args>
+		Optional(Args&&...);
+
+		~Optional();
+
+		Optional& operator=(Optional&&);
+		Optional& operator=(const Optional&);
+
+		template<typename... Args>
+		Optional& emplace(Args&&...);
+
+		T* operator->();
+		const T* operator->() const;
+
+		T& operator*();
+		const T& operator*() const;
+
+		bool has_value() const;
+
+		T release_value();
+		T& value();
+		const T& value() const;
+
+		void clear();
+
+	private:
+		alignas(T) uint8_t m_storage[sizeof(T)];
+		bool m_has_value { false };
+	};
+
+	template<typename T>
+	Optional<T>::Optional()
+		: m_has_value(false)
+	{}
+
+	template<typename T>
+	Optional<T>::Optional(Optional<T>&& other)
+		: m_has_value(other.has_value())
+	{
+		if (other.has_value())
+			new (m_storage) T(move(other.release_value()));
+	}
+
+	template<typename T>
+	Optional<T>::Optional(const Optional<T>& other)
+		: m_has_value(other.has_value())
+	{
+		if (other.has_value())
+			new (m_storage) T(other.value());
+	}
+
+	template<typename T>
+	Optional<T>::Optional(const T& value)
+		: m_has_value(true)
+	{
+		new (m_storage) T(value);	
+	}
+
+	template<typename T>
+	Optional<T>::Optional(T&& value)
+		: m_has_value(true)
+	{
+		new (m_storage) T(move(value));
+	}
+
+	template<typename T>
+	template<typename... Args>
+	Optional<T>::Optional(Args&&... args)
+		: m_has_value(true)
+	{
+		new (m_storage) T(forward<Args>(args)...);
+	}
+
+	template<typename T>
+	Optional<T>::~Optional()
+	{
+		clear();
+	}
+
+	template<typename T>
+	Optional<T>& Optional<T>::operator=(Optional&& other)
+	{
+		clear();
+		m_has_value = other.has_value();
+		if (other.has_value())
+			new (m_storage) T(move(other.release_value()));
+		return *this;
+	}
+
+	template<typename T>
+	Optional<T>& Optional<T>::operator=(const Optional& other)
+	{
+		clear();
+		m_has_value = other.has_value();
+		if (other.has_value)
+			new (m_storage) T(other.value());
+		return *this;
+	}
+
+	template<typename T>
+	template<typename... Args>
+	Optional<T>& Optional<T>::emplace(Args&&... args)
+	{
+		clear();
+		m_has_value = true;
+		new (m_storage) T(forward<Args>(args)...);
+		return *this;
+	}
+
+	template<typename T>
+	T* Optional<T>::operator->()
+	{
+		ASSERT(has_value());
+		return &value();
+	}
+
+	template<typename T>
+	const T* Optional<T>::operator->() const
+	{
+		ASSERT(has_value());
+		return &value();
+	}
+
+	template<typename T>
+	T& Optional<T>::operator*()
+	{
+		ASSERT(has_value());
+		return value();
+	}
+
+	template<typename T>
+	const T& Optional<T>::operator*() const
+	{
+		ASSERT(has_value());
+		return value();
+	}
+
+	template<typename T>
+	bool Optional<T>::has_value() const
+	{
+		return m_has_value;
+	}
+
+	template<typename T>
+	T Optional<T>::release_value()
+	{
+		ASSERT(has_value());
+		T released_value = move(value());
+		value().~T();
+		m_has_value = false;
+		return move(released_value);
+	}
+
+	template<typename T>
+	T& Optional<T>::value()
+	{
+		ASSERT(has_value());
+		return (T&)m_storage;
+	}
+
+	template<typename T>
+	const T& Optional<T>::value() const
+	{
+		ASSERT(has_value());
+		return (const T&)m_storage;
+	}
+
+	template<typename T>
+	void Optional<T>::clear()
+	{
+		if (m_has_value)
+			value().~T();
+		m_has_value = false;
+	}
+
+}

BAN/include/BAN/Queue.h

@@ -1,9 +1,10 @@
 #pragma once
 
 #include <BAN/Errors.h>
+#include <BAN/Iterators.h>
 #include <BAN/Math.h>
-#include <BAN/Memory.h>
 #include <BAN/Move.h>
+#include <BAN/New.h>
 
 namespace BAN
 {
@@ -14,6 +15,8 @@ namespace BAN
 	public:
 		using size_type = size_t;
 		using value_type = T;
+		using iterator = IteratorSimple<T, Queue>;
+		using const_iterator = ConstIteratorSimple<T, Queue>;
 
 	public:
 		Queue() = default;
@@ -32,6 +35,11 @@ namespace BAN
 		ErrorOr<void> reserve(size_type);
 		ErrorOr<void> shrink_to_fit();
 
+		iterator begin() { return iterator(m_data); }
+		iterator end() { return iterator(m_data + m_size); }
+		const_iterator begin() const { return const_iterator(m_data); }
+		const_iterator end() const { return const_iterator(m_data + m_size); }
+
 		void pop();
 		void clear();
 

BAN/include/BAN/RefPtr.h

@@ -1,27 +1,12 @@
 #pragma once
 
-
 #include <BAN/Errors.h>
 #include <BAN/Move.h>
 #include <BAN/NoCopyMove.h>
-
-#if defined(__is_kernel)
-	#include <kernel/kmalloc.h>
-#else
-	#include <stdlib.h>
-#endif
-
 #include <stdint.h>
 
 namespace BAN
 {
-	#if defined(__is_kernel)
-		static constexpr void*(&allocator)(size_t) = kmalloc;
-		static constexpr void(&deallocator)(void*) = kfree;
-	#else
-		static constexpr void*(&allocator)(size_t) = malloc;
-		static constexpr void(&deallocator)(void*) = free;
-	#endif
 
 	template<typename T>
 	class RefCounted
@@ -68,7 +53,6 @@ namespace BAN
 			if (m_pointer)
 				m_pointer->ref();
 		}
-
 		~RefPtr() { clear(); }
 
 		template<typename U>
@@ -90,6 +74,10 @@ namespace BAN
 
 		RefPtr(const RefPtr& other) { *this = other; }
 		RefPtr(RefPtr&& other) { *this = move(other); }
+		template<typename U>
+		RefPtr(const RefPtr<U>& other) { *this = other; }
+		template<typename U>
+		RefPtr(RefPtr<U>&& other) { *this = move(other); }
 
 		RefPtr& operator=(const RefPtr& other)
 		{
@@ -108,6 +96,25 @@ namespace BAN
 			return *this;
 		}
 
+		template<typename U>
+		RefPtr& operator=(const RefPtr<U>& other)
+		{
+			clear();
+			m_pointer = other.m_pointer;
+			if (m_pointer)
+				m_pointer->ref();
+			return *this;
+		}
+
+		template<typename U>
+		RefPtr& operator=(RefPtr<U>&& other)
+		{
+			clear();
+			m_pointer = other.m_pointer;
+			other.m_pointer = nullptr;
+			return *this;
+		}
+
 		T* ptr() { ASSERT(!empty()); return m_pointer; }
 		const T* ptr() const { ASSERT(!empty()); return m_pointer; }
 
@@ -129,9 +136,9 @@ namespace BAN
 
 	private:
 		T* m_pointer = nullptr;
+
+		template<typename U>
+		friend class RefPtr;
 	};
 
 }
-
-inline void* operator new(size_t, void* addr)	{ return addr; }
-inline void* operator new[](size_t, void* addr)	{ return addr; }

BAN/include/BAN/ScopeGuard.h

@@ -13,10 +13,16 @@ namespace BAN
 		{ }
 		~ScopeGuard()
 		{
-			m_func();
+			if (m_enabled)
+				m_func();
+		}
+		void disable()
+		{
+			m_enabled = false;
 		}
 	private:
 		BAN::Function<void()> m_func;
+		bool m_enabled { true };
 	};
 
 }

BAN/include/BAN/Span.h

@@ -0,0 +1,134 @@
+#pragma once
+
+#include <BAN/Assert.h>
+#include <BAN/Iterators.h>
+
+#include <stddef.h>
+
+namespace BAN
+{
+
+	template<typename T>
+	class Span
+	{
+	public:
+		using value_type = T;
+		using size_type = size_t;
+		using iterator = IteratorSimple<T, Span>;
+		using const_iterator = ConstIteratorSimple<T, Span>;
+
+	public:
+		Span() = default;
+		Span(T*, size_type);
+		Span(Span<T>&);
+		template<typename S>
+		requires(is_same_v<T, const S>)
+		Span(const Span<S>&);
+
+		iterator begin() { return iterator(m_data); }
+		iterator end() { return iterator(m_data + m_size); }
+		const_iterator begin() const { return const_iterator(m_data); }
+		const_iterator end() const { return const_iterator(m_data + m_size); }
+
+		T& operator[](size_type);
+		const T& operator[](size_type) const;
+
+		T* data();
+		const T* data() const;
+
+		bool empty() const;
+		size_type size() const;
+
+		void clear();
+
+		Span slice(size_type, size_type = ~size_type(0));
+
+		Span<const T> as_const() const { return Span<const T>(m_data, m_size); }
+
+	private:
+		T* m_data = nullptr;
+		size_type m_size = 0;
+	};
+
+	template<typename T>
+	Span<T>::Span(T* data, size_type size)
+		: m_data(data)
+		, m_size(size)
+	{
+	}
+
+	template<typename T>
+	Span<T>::Span(Span& other)
+		: m_data(other.data())
+		, m_size(other.size())
+	{
+	}
+
+	template<typename T>
+	template<typename S>
+	requires(is_same_v<T, const S>)
+	Span<T>::Span(const Span<S>& other)
+		: m_data(other.data())
+		, m_size(other.size())
+	{
+	}
+
+	template<typename T>
+	T& Span<T>::operator[](size_type index)
+	{
+		ASSERT(m_data);
+		ASSERT(index < m_size);
+		return m_data[index];
+	}
+
+	template<typename T>
+	const T& Span<T>::operator[](size_type index) const
+	{
+		ASSERT(m_data);
+		ASSERT(index < m_size);
+		return m_data[index];
+	}
+
+	template<typename T>
+	T* Span<T>::data()
+	{
+		return m_data;
+	}
+
+	template<typename T>
+	const T* Span<T>::data() const
+	{
+		return m_data;
+	}
+
+	template<typename T>
+	bool Span<T>::empty() const
+	{
+		return m_size == 0;
+	}
+
+	template<typename T>
+	typename Span<T>::size_type Span<T>::size() const
+	{
+		return m_size;
+	}
+
+	template<typename T>
+	void Span<T>::clear()
+	{
+		m_data = nullptr;
+		m_size = 0;
+	}
+
+	template<typename T>
+	Span<T> Span<T>::slice(size_type start, size_type length)
+	{
+		ASSERT(m_data);
+		ASSERT(start <= m_size);
+		if (length == ~size_type(0))
+			length = m_size - start;
+		ASSERT(m_size - start >= length);
+		return Span(m_data + start, length);
+	}
+
+}

BAN/include/BAN/String.h

@@ -1,8 +1,10 @@
 #pragma once
 
-#include <BAN/ForwardList.h>
+#include <BAN/Errors.h>
 #include <BAN/Formatter.h>
+#include <BAN/ForwardList.h>
 #include <BAN/Hash.h>
+#include <BAN/Iterators.h>
 
 namespace BAN
 {
@@ -11,6 +13,9 @@ namespace BAN
 	{
 	public:
 		using size_type = size_t;
+		using iterator = IteratorSimple<char, String>;
+		using const_iterator = ConstIteratorSimple<char, String>;
+		static constexpr size_type sso_capacity = 15;
 
 	public:
 		String();
@@ -30,18 +35,26 @@ namespace BAN
 		ErrorOr<void> insert(char, size_type);
 		ErrorOr<void> insert(StringView, size_type);
 		ErrorOr<void> append(StringView);
-		ErrorOr<void> append(const String&);
 
 		void pop_back();
 		void remove(size_type);
-		void erase(size_type, size_type);
 
 		void clear();
 
-		char operator[](size_type) const;
-		char& operator[](size_type);
+		const_iterator begin() const	{ return const_iterator(data()); }
+		iterator begin()				{ return iterator(data()); }
+		const_iterator end() const		{ return const_iterator(data() + size()); }
+		iterator end()					{ return iterator(data() + size()); }
+
+		char front() const	{ ASSERT(m_size > 0); return data()[0]; }
+		char& front()		{ ASSERT(m_size > 0); return data()[0]; }
+
+		char back() const	{ ASSERT(m_size > 0); return data()[m_size - 1]; }
+		char& back()		{ ASSERT(m_size > 0); return data()[m_size - 1]; }
+
+		char operator[](size_type index) const	{ ASSERT(index < m_size); return data()[index]; }
+		char& operator[](size_type index)		{ ASSERT(index < m_size); return data()[index]; }
 
-		bool operator==(const String&) const;
 		bool operator==(StringView) const;
 		bool operator==(const char*) const;
 
@@ -49,31 +62,48 @@ namespace BAN
 		ErrorOr<void> reserve(size_type);
 		ErrorOr<void> shrink_to_fit();
 
-		StringView sv() const;
+		StringView sv() const	{ return StringView(data(), size()); }
 
-		bool empty() const;
-		size_type size() const;
+		bool empty() const		{ return m_size == 0; }
+		size_type size() const	{ return m_size; }
 		size_type capacity() const;
 
+		char* data();
 		const char* data() const;
 
 	private:
 		ErrorOr<void> ensure_capacity(size_type);
 
-		ErrorOr<void> copy_impl(StringView);
-		void move_impl(String&&);
+		bool has_sso() const;
+
+		bool fits_in_sso() const { return fits_in_sso(m_size); }
+		static bool fits_in_sso(size_type size) { return size < sso_capacity; }
 
 	private:
-		char*		m_data		= nullptr;
-		size_type	m_capacity	= 0;
-		size_type	m_size		= 0;	
+		struct SSOStorage
+		{
+			char data[sso_capacity + 1] {};
+		};
+		struct GeneralStorage
+		{
+			size_type capacity	{ 0 };
+			char* data			{ nullptr };
+		};
+
+	private:
+		union {
+			SSOStorage sso_storage;
+			GeneralStorage general_storage;
+		} m_storage										{ .sso_storage = SSOStorage() };
+		size_type m_size	: sizeof(size_type) * 8 - 1	{ 0 };
+		size_type m_has_sso	: 1							{ true };
 	};
 
 	template<typename... Args>
 	String String::formatted(const char* format, const Args&... args)
 	{
 		String result;
-		BAN::Formatter::print([&](char c){ result.push_back(c); }, format, args...);
+		BAN::Formatter::print([&](char c){ MUST(result.push_back(c)); }, format, args...);
 		return result;
 	}
 

BAN/include/BAN/StringView.h

@@ -2,6 +2,7 @@
 
 #include <BAN/ForwardList.h>
 #include <BAN/Formatter.h>
+#include <BAN/Iterators.h>
 
 namespace BAN
 {
@@ -10,12 +11,16 @@ namespace BAN
 	{
 	public:
 		using size_type = size_t;
+		using const_iterator = ConstIteratorSimple<char, StringView>;
 
 	public:
 		StringView();
 		StringView(const String&);
 		StringView(const char*, size_type = -1);
 
+		const_iterator begin() const { return const_iterator(m_data); }
+		const_iterator end() const { return const_iterator(m_data + m_size); }
+
 		char operator[](size_type) const;
 
 		bool operator==(const String&) const;
@@ -30,6 +35,7 @@ namespace BAN
 		char back() const;
 		char front() const;
 
+		bool contains(char) const;
 		size_type count(char) const;
 
 		bool empty() const;

BAN/include/BAN/Time.h

@@ -9,15 +9,18 @@ namespace BAN
 
 	struct Time
 	{
-		uint8_t	second;
-		uint8_t	minute;
-		uint8_t	hour;
-		uint8_t week_day;
-		uint8_t	day;
+		uint32_t year;
 		uint8_t	month;
-		int		year;
+		uint8_t	day;
+		uint8_t	hour;
+		uint8_t	minute;
+		uint8_t	second;
+		uint8_t week_day;
 	};
 
+	uint64_t to_unix_time(const BAN::Time&);
+	BAN::Time from_unix_time(uint64_t);
+
 }
 
 namespace BAN::Formatter

BAN/include/BAN/Traits.h

@@ -30,6 +30,10 @@ namespace BAN
 	template<typename T> struct maybe_const<true, T> { using type = const T; };
 	template<bool B, typename T> using maybe_const_t = typename maybe_const<B, T>::type;
 
+	template<bool B, typename T1, typename T2> struct either_or { using type = T2; };
+	template<typename T1, typename T2> struct either_or<true, T1, T2> { using type = T1; };
+	template<bool B, typename T1, typename T2> using either_or_t = typename either_or<B, T1, T2>::type;
+
 	struct true_type { static constexpr bool value = true; };
 	struct false_type { static constexpr bool value = false; };
 
@@ -40,6 +44,7 @@ namespace BAN
 	template<typename T> struct is_lvalue_reference		: false_type {};
 	template<typename T> struct is_lvalue_reference<T&>	: true_type {};
 	template<typename T> inline constexpr bool is_lvalue_reference_v = is_lvalue_reference<T>::value;
+	template<typename T> concept lvalue_reference = is_lvalue_reference_v<T>;
 
 	template<typename T> struct is_integral { static constexpr bool value = requires (T t, T* p, void (*f)(T)) { reinterpret_cast<T>(t); f(0); p + t; }; };
 	template<typename T> inline constexpr bool is_integral_v = is_integral<T>::value;
@@ -60,6 +65,21 @@ namespace BAN
 	template<typename T> inline constexpr bool is_pointer_v = is_pointer<T>::value;
 	template<typename T> concept pointer = is_pointer_v<T>;
 
+	template<typename T> struct is_const			: false_type {};
+	template<typename T> struct is_const<const T>	: true_type {};
+	template<typename T> inline constexpr bool is_const_v = is_const<T>::value;
+
+	template<typename T> struct is_arithmetic { static constexpr bool value = is_integral_v<T> || is_floating_point_v<T>; };
+	template<typename T> inline constexpr bool is_arithmetic_v = is_arithmetic<T>::value;
+
+	namespace detail
+	{
+		template<typename T, bool = is_arithmetic_v<T>> struct is_signed { static constexpr bool value = T(-1) < T(0); };
+		template<typename T> struct is_signed<T, false> : false_type {};
+	}
+	template<typename T> struct is_signed : detail::is_signed<T> {};
+	template<typename T> inline constexpr bool is_signed_v = is_signed<T>::value;
+
 	template<typename T> struct less	{ constexpr bool operator()(const T& lhs, const T& rhs) const { return lhs < rhs; } };
 	template<typename T> struct equal	{ constexpr bool operator()(const T& lhs, const T& rhs) const { return lhs == rhs; } };
 	template<typename T> struct greater	{ constexpr bool operator()(const T& lhs, const T& rhs) const { return lhs > rhs; } };

BAN/include/BAN/UTF8.h

@@ -3,26 +3,79 @@
 #include <stddef.h>
 #include <stdint.h>
 
-namespace BAN
+namespace BAN::UTF8
 {
 
-	static constexpr uint16_t utf8_to_codepoint(uint8_t* bytes, size_t count)
+	static constexpr uint32_t invalid = 0xFFFFFFFF;
+
+	constexpr uint32_t byte_length(uint8_t first_byte)
 	{
-		if (count > 3)
-			return 0xFFFF;
+		if ((first_byte & 0x80) == 0x00)
+			return 1;
+		if ((first_byte & 0xE0) == 0xC0)
+			return 2;
+		if ((first_byte & 0xF0) == 0xE0)
+			return 3;
+		if ((first_byte & 0xF8) == 0xF0)
+			return 4;
+		return 0;
+	}
 
-		for (size_t i = 1; i < count; i++)
+	constexpr uint32_t to_codepoint(uint8_t* bytes)
+	{
+		uint32_t length = byte_length(bytes[0]);
+
+		for (uint32_t i = 1; i < length; i++)
 			if ((bytes[i] & 0xC0) != 0x80)
-				return 0xFFFF;
+				return UTF8::invalid;
 		
-		switch (count)
+		switch (length)
 		{
-			case 1: return   bytes[0];
-			case 2: return ((bytes[0] & 0x1F) <<  6) |  (bytes[1] & 0x3F);
-			case 3: return ((bytes[0] & 0x1F) << 12) | ((bytes[1] & 0x3F) << 6) | (bytes[2] & 0x3F);
+			case 1: return ((bytes[0] & 0x80) != 0x00) ? UTF8::invalid :   bytes[0];
+			case 2: return ((bytes[0] & 0xE0) != 0xC0) ? UTF8::invalid : ((bytes[0] & 0x1F) <<  6) |  (bytes[1] & 0x3F);
+			case 3: return ((bytes[0] & 0xF0) != 0xE0) ? UTF8::invalid : ((bytes[0] & 0x0F) << 12) | ((bytes[1] & 0x3F) <<  6) |  (bytes[2] & 0x3F);
+			case 4: return ((bytes[0] & 0xF8) != 0xF0) ? UTF8::invalid : ((bytes[0] & 0x07) << 18) | ((bytes[1] & 0x3F) << 12) | ((bytes[2] & 0x3F) << 6) | (bytes[3] & 0x3F);
 		}
 
-		return 0xFFFF;
+		return UTF8::invalid;
+	}
+
+	template<typename T>
+	constexpr bool from_codepoints(const T* codepoints, size_t count, char* out)
+	{
+		uint8_t* ptr = (uint8_t*)out;
+
+		for (size_t i = 0; i < count; i++)
+		{
+			if (codepoints[i] < 0x80)
+			{
+				*ptr++ = codepoints[i];
+			}
+			else if (codepoints[i] < 0x800)
+			{
+				*ptr++ = 0xC0 | ((codepoints[i] >> 6) & 0x1F);
+				*ptr++ = 0x80 | ((codepoints[i] >> 0) & 0x3F);
+			}
+			else if (codepoints[i] < 0x10000)
+			{
+				*ptr++ = 0xE0 | ((codepoints[i] >> 12) & 0x0F);
+				*ptr++ = 0x80 | ((codepoints[i] >>  6) & 0x3F);
+				*ptr++ = 0x80 | ((codepoints[i] >>  0) & 0x3F);
+			}
+			else if (codepoints[i] < 0x110000)
+			{
+				*ptr++ = 0xF0 | ((codepoints[i] >> 18) & 0x07);
+				*ptr++ = 0x80 | ((codepoints[i] >> 12) & 0x3F);
+				*ptr++ = 0x80 | ((codepoints[i] >>  6) & 0x3F);
+				*ptr++ = 0x80 | ((codepoints[i] >>  0) & 0x3F);
+			}
+			else
+			{
+				return false;
+			}
+		}
+
+		return true;
 	}
 
 }

BAN/include/BAN/UniqPtr.h

@@ -0,0 +1,98 @@
+#pragma once
+
+#include <BAN/Errors.h>
+#include <BAN/NoCopyMove.h>
+
+namespace BAN
+{
+
+	template<typename T>
+	class UniqPtr
+	{
+		BAN_NON_COPYABLE(UniqPtr);
+
+	public:
+		UniqPtr() = default;
+
+		template<typename U>
+		UniqPtr(UniqPtr<U>&& other)
+		{
+			m_pointer = other.m_pointer;
+			other.m_pointer = nullptr;
+		}
+
+		~UniqPtr()
+		{
+			clear();
+		}
+
+		static UniqPtr adopt(T* pointer)
+		{
+			UniqPtr uniq;
+			uniq.m_pointer = pointer;
+			return uniq;
+		}
+
+		template<typename... Args>
+		static BAN::ErrorOr<UniqPtr> create(Args&&... args)
+		{
+			UniqPtr uniq;
+			uniq.m_pointer = new T(BAN::forward<Args>(args)...);
+			if (uniq.m_pointer == nullptr)
+				return BAN::Error::from_errno(ENOMEM);
+			return uniq;
+		}
+
+		template<typename U>
+		UniqPtr& operator=(UniqPtr<U>&& other)
+		{
+			clear();
+			m_pointer = other.m_pointer;
+			other.m_pointer = nullptr;
+			return *this;
+		}
+
+		T& operator*()
+		{
+			ASSERT(m_pointer);
+			return *m_pointer;
+		}
+
+		const T& operator*() const
+		{
+			ASSERT(m_pointer);
+			return *m_pointer;
+		}
+
+		T* operator->()
+		{
+			ASSERT(m_pointer);
+			return m_pointer;	
+		}
+
+		const T* operator->() const
+		{
+			ASSERT(m_pointer);
+			return m_pointer;
+		}
+
+		T* ptr() { return m_pointer; }
+		const T* ptr() const { return m_pointer; }
+
+		void clear()
+		{
+			if (m_pointer)
+				delete m_pointer;
+			m_pointer = nullptr;
+		}
+
+		operator bool() const { return m_pointer != nullptr; }
+
+	private:
+		T* m_pointer = nullptr;
+
+		template<typename U>
+		friend class UniqPtr;
+	};
+
+}

BAN/include/BAN/Variant.h

@@ -4,144 +4,290 @@
 #include <BAN/Math.h>
 #include <BAN/Move.h>
 
+#include <string.h>
+
 namespace BAN
 {
 
-	template<typename T1, typename T2>
+	namespace detail
+	{
+
+		template<typename T>
+		constexpr size_t size_ref_as_ptr() { return is_lvalue_reference_v<T> ? sizeof(remove_reference_t<T>*) : sizeof(T); }
+		template<typename T>
+		constexpr size_t align_ref_as_ptr() { return is_lvalue_reference_v<T> ? alignof(remove_reference_t<T>*) : alignof(T); }
+
+		template<typename T>
+		constexpr size_t max_size_ref_as_ptr() { return size_ref_as_ptr<T>(); }
+		template<typename T0, typename T1, typename... Ts>
+		constexpr size_t max_size_ref_as_ptr() { return size_ref_as_ptr<T0>() > size_ref_as_ptr<T1>() ? max_size_ref_as_ptr<T0, Ts...>() : max_size_ref_as_ptr<T1, Ts...>(); }
+
+		template<typename T>
+		constexpr size_t max_align_ref_as_ptr() { return align_ref_as_ptr<T>(); }
+		template<typename T0, typename T1, typename... Ts>
+		constexpr size_t max_align_ref_as_ptr() { return align_ref_as_ptr<T0>() > align_ref_as_ptr<T1>() ? max_align_ref_as_ptr<T0, Ts...>() : max_align_ref_as_ptr<T1, Ts...>(); }
+
+		template<typename T, typename T0, typename... Ts>
+		constexpr size_t index()
+		{
+			if constexpr(is_same_v<T, T0>)
+				return 0;
+			else if constexpr(sizeof...(Ts) == 0)
+				return 1;
+			else
+				return index<T, Ts...>() + 1;
+		}
+
+		template<typename T, typename... Ts>
+		void destruct(size_t index, uint8_t* data)
+		{
+			if (index == 0)
+				if constexpr(!is_lvalue_reference_v<T>)
+					reinterpret_cast<T*>(data)->~T();
+				else;
+			else if constexpr(sizeof...(Ts) > 0)
+				destruct<Ts...>(index - 1, data);
+			else
+				ASSERT_NOT_REACHED();
+		}
+
+		template<typename T, typename... Ts>
+		void move_construct(size_t index, uint8_t* source, uint8_t* target)
+		{
+			if (index == 0)
+				if constexpr(!is_lvalue_reference_v<T>)
+					new (target) T(move(*reinterpret_cast<T*>(source)));
+				else
+					memcpy(target, source, sizeof(remove_reference_t<T>*));
+			else if constexpr(sizeof...(Ts) > 0)
+				move_construct<Ts...>(index - 1, source, target);
+			else
+				ASSERT_NOT_REACHED();
+		}
+
+		template<typename T, typename... Ts>
+		void copy_construct(size_t index, const uint8_t* source, uint8_t* target)
+		{
+			if (index == 0)
+				if constexpr(!is_lvalue_reference_v<T>)
+					new (target) T(*reinterpret_cast<const T*>(source));
+				else
+					memcpy(target, source, sizeof(remove_reference_t<T>*));
+			else if constexpr(sizeof...(Ts) > 0)
+				copy_construct<Ts...>(index - 1, source, target);
+			else
+				ASSERT_NOT_REACHED();
+		}
+
+		template<typename T, typename... Ts>
+		void move_assign(size_t index, uint8_t* source, uint8_t* target)
+		{
+			if (index == 0)
+				if constexpr(!is_lvalue_reference_v<T>)
+					*reinterpret_cast<T*>(target) = move(*reinterpret_cast<T*>(source));
+				else
+					memcpy(target, source, sizeof(remove_reference_t<T>*));
+			else if constexpr(sizeof...(Ts) > 0)
+				move_assign<Ts...>(index - 1, source, target);
+			else
+				ASSERT_NOT_REACHED();
+		}
+
+		template<typename T, typename... Ts>
+		void copy_assign(size_t index, const uint8_t* source, uint8_t* target)
+		{
+			if (index == 0)
+				if constexpr(!is_lvalue_reference_v<T>)
+					*reinterpret_cast<T*>(target) = *reinterpret_cast<const T*>(source);
+				else
+					memcpy(target, source, sizeof(remove_reference_t<T>*));
+			else if constexpr(sizeof...(Ts) > 0)
+				copy_assign<Ts...>(index - 1, source, target);
+			else
+				ASSERT_NOT_REACHED();
+		}
+
+	}
+
+	template<typename... Ts>
+		requires (!is_const_v<Ts> && ...)
 	class Variant
 	{
-	public:
-		static_assert(!is_same_v<T1, T2>);
+	private:
+		template<typename T>
+		static constexpr bool can_have() { return detail::index<T, Ts...>() != invalid_index(); }
+		static constexpr size_t invalid_index() { return sizeof...(Ts); }
 
+	public:
 		Variant() = default;
 
-		Variant(const T1& value)	{ set(value); }
-		Variant(T1&& value)			{ set(move(value)); }
-		Variant(const T2& value)	{ set(value); }
-		Variant(T2&& value)			{ set(move(value)); }
+		Variant(Variant&& other)
+			: m_index(other.m_index)
+		{
+			detail::move_construct<Ts...>(other.m_index, other.m_storage, m_storage);
+			other.clear();
+		}
 
-		Variant(const Variant<T1, T2>& other)	{ *this = other; }
-		Variant(Variant<T1, T2>&& other)		{ *this = move(other); }
+		Variant(const Variant& other)
+			: m_index(other.m_index)
+		{
+			detail::copy_construct<Ts...>(other.m_index, other.m_storage, m_storage);
+		}
 
-		~Variant() { clear(); }
+		template<typename T>
+		Variant(T&& value) requires (can_have<T>() && !is_lvalue_reference_v<T>)
+			: m_index(detail::index<T, Ts...>())
+		{
+			new (m_storage) T(move(value));	
+		}
 
-		Variant<T1, T2>& operator=(const Variant<T1, T2>& other);
-		Variant<T1, T2>& operator=(Variant<T1, T2>&& other);
+		template<typename T>
+		Variant(const T& value) requires (can_have<T>() && !is_lvalue_reference_v<T>)
+			: m_index(detail::index<T, Ts...>())
+		{
+			new (m_storage) T(value);	
+		}
 
-		template<typename U>
-		bool is() const;
+		~Variant()
+		{
+			clear();
+		}
 
-		template<typename U>
-		void set(U&&);
-		template<typename U>
-		void set(const U& value) { set(move(U(value))); } 
+		Variant& operator=(Variant&& other)
+		{
+			if (m_index == other.m_index)
+				detail::move_assign<Ts...>(m_index, other.m_storage, m_storage);
+			else
+			{
+				clear();
+				detail::move_construct<Ts...>(other.m_index, other.m_storage, m_storage);
+				m_index = other.m_index;
+			}
+			other.clear();
+			return *this;
+		}
 
-		template<typename U>
-		const U& get() const;
-		template<typename U>
-		U& get();
+		Variant& operator=(const Variant& other)
+		{
+			if (m_index == other.m_index)
+				detail::copy_assign<Ts...>(m_index, other.m_storage, m_storage);
+			else
+			{
+				clear();
+				detail::copy_construct<Ts...>(other.m_index, other.m_storage, m_storage);
+				m_index = other.m_index;
+			}
+			return *this;
+		}
 
-		void clear();
+		template<typename T>
+		Variant& operator=(T&& value) requires (can_have<T>() && !is_lvalue_reference_v<T>)
+		{
+			if (size_t index = detail::index<T, Ts...>(); index == m_index)
+				get<T>() = move(value);
+			else
+			{
+				clear();
+				new (m_storage) T(move(value));
+				m_index = index;
+			}
+			return *this;
+		}
+
+		template<typename T>
+		Variant& operator=(const T& value) requires (can_have<T>() && !is_lvalue_reference_v<T>)
+		{
+			if (size_t index = detail::index<T, Ts...>(); index == m_index)
+				get<T>() = value;
+			else
+			{
+				clear();
+				new (m_storage) T(value);
+				m_index = index;
+			}
+			return *this;
+		}
+
+		template<typename T>
+		bool has() const requires (can_have<T>())
+		{
+			return m_index == detail::index<T, Ts...>();
+		}
+
+		template<typename T>
+		void set(T&& value) requires (can_have<T>() && !is_lvalue_reference_v<T>)
+		{
+			if (has<T>())
+				get<T>() = move(value);
+			else
+			{
+				clear();
+				m_index = detail::index<T, Ts...>();
+				new (m_storage) T(move(value));
+			}
+		}
+
+		template<typename T>
+		void set(const T& value) requires (can_have<T>() && !is_lvalue_reference_v<T>)
+		{
+			if (has<T>())
+				get<T>() = value;
+			else
+			{
+				clear();
+				m_index = detail::index<T, Ts...>();
+				new (m_storage) T(value);
+			}
+		}
+
+		template<typename T>
+		void set(T value) requires (can_have<T>() && is_lvalue_reference_v<T>)
+		{
+			clear();
+			m_index = detail::index<T, Ts...>();
+			*reinterpret_cast<remove_reference_t<T>**>(m_storage) = &value;
+		}
+
+		template<typename T>
+		T& get() requires (can_have<T>() && !is_lvalue_reference_v<T>)
+		{
+			ASSERT(has<T>());
+			return *reinterpret_cast<T*>(m_storage);
+		}
+
+		template<typename T>
+		const T& get() const requires (can_have<T>() && !is_lvalue_reference_v<T>)
+		{
+			ASSERT(has<T>());
+			return *reinterpret_cast<const T*>(m_storage);
+		}
+
+		template<typename T>
+		T get() requires (can_have<T>() && is_lvalue_reference_v<T>)
+		{
+			ASSERT(has<T>());
+			return **reinterpret_cast<remove_reference_t<T>**>(m_storage);
+		}
+
+		template<typename T>
+		const T get() const requires (can_have<T>() && is_lvalue_reference_v<T>)
+		{
+			ASSERT(has<T>());
+			return **reinterpret_cast<const remove_reference_t<T>**>(m_storage);
+		}
+
+		void clear()
+		{
+			if (m_index != invalid_index())
+			{
+				detail::destruct<Ts...>(m_index, m_storage);
+				m_index = invalid_index();
+			}
+		}
 
 	private:
-		static constexpr uint32_t m_size = Math::max(sizeof(T1), sizeof(T2));
-		uint8_t m_storage[m_size] = {};
-		uint32_t m_index = 0;
+		alignas(detail::max_align_ref_as_ptr<Ts...>()) uint8_t m_storage[detail::max_size_ref_as_ptr<Ts...>()] {};
+		size_t m_index { invalid_index() };
 	};
 
-	template<typename T1, typename T2>
-	Variant<T1, T2>& Variant<T1, T2>::operator=(const Variant<T1, T2>& other)
-	{
-		clear();
-		if (other.is<T1>())
-			set(other.get<T1>());
-		if (other.is<T2>())
-			set(other.get<T2>());
-		return *this;
-	}
-
-	template<typename T1, typename T2>
-	Variant<T1, T2>& Variant<T1, T2>::operator=(Variant<T1, T2>&& other)
-	{
-		clear();
-		if (other.is<T1>())
-			set(move(other.get<T1>()));
-		if (other.is<T2>())
-			set(move(other.get<T2>()));
-		other.clear();
-		return *this;
-	}
-
-	template<typename T1, typename T2>
-	template<typename U>
-	bool Variant<T1, T2>::is() const
-	{
-		if constexpr(is_same_v<T1, U>)
-			return m_index == 1;
-		if constexpr(is_same_v<T2, U>)
-			return m_index == 2;
-		return false;
-	}
-
-
-	template<typename T1, typename T2>
-	template<typename U>
-	void Variant<T1, T2>::set(U&& value)
-	{
-		static_assert(is_same_v<T1, U> || is_same_v<T2, U>);
-		clear();
-		if constexpr(is_same_v<T1, U>)
-		{
-			new (m_storage) T1(move(value));
-			m_index = 1;
-		}
-		if constexpr(is_same_v<T2, U>)
-		{
-			new (m_storage) T2(move(value));
-			m_index = 2;
-		}
-	}
-
-	template<typename T1, typename T2>
-	template<typename U>
-	const U& Variant<T1, T2>::get() const
-	{
-		static_assert(is_same_v<T1, U> || is_same_v<T2, U>);
-		if constexpr(is_same_v<T1, U>)
-		{
-			ASSERT(m_index == 1);
-			return *(T1*)m_storage;
-		}
-		if constexpr(is_same_v<T2, U>)
-		{
-			ASSERT(m_index == 2);
-			return *(T2*)m_storage;
-		}
-	}
-
-	template<typename T1, typename T2>
-	template<typename U>
-	U& Variant<T1, T2>::get()
-	{
-		static_assert(is_same_v<T1, U> || is_same_v<T2, U>);
-		if constexpr(is_same_v<T1, U>)
-		{
-			ASSERT(m_index == 1);
-			return *(T1*)m_storage;
-		}
-		if constexpr(is_same_v<T2, U>)
-		{
-			ASSERT(m_index == 2);
-			return *(T2*)m_storage;
-		}
-	}
-
-	template<typename T1, typename T2>
-	void Variant<T1, T2>::clear()
-	{
-		if (is<T1>()) ((T1*)m_storage)->~T1();
-		if (is<T2>()) ((T2*)m_storage)->~T2();
-		m_index = 0;
-	}
-
 }

BAN/include/BAN/Vector.h

@@ -1,16 +1,15 @@
 #pragma once
 
 #include <BAN/Errors.h>
+#include <BAN/Iterators.h>
 #include <BAN/Math.h>
-#include <BAN/Memory.h>
 #include <BAN/Move.h>
+#include <BAN/New.h>
+#include <BAN/Span.h>
 
 namespace BAN
 {
 
-	template<typename T, bool CONST>
-	class VectorIterator;
-
 	// T must be move assignable, move constructable (and copy constructable for some functions)
 	template<typename T>
 	class Vector
@@ -18,8 +17,8 @@ namespace BAN
 	public:
 		using size_type = size_t;
 		using value_type = T;
-		using iterator = VectorIterator<T, false>;
-		using const_iterator = VectorIterator<T, true>;
+		using iterator = IteratorSimple<T, Vector>;
+		using const_iterator = ConstIteratorSimple<T, Vector>;
 
 	public:
 		Vector() = default;
@@ -40,10 +39,10 @@ namespace BAN
 		ErrorOr<void> insert(size_type, T&&);
 		ErrorOr<void> insert(size_type, const T&);
 		
-		iterator begin()				{ return iterator      (m_data); }
-		const_iterator begin() const	{ return const_iterator(m_data); }
-		iterator end()					{ return iterator      (m_data + m_size); }
-		const_iterator end() const		{ return const_iterator(m_data + m_size); }
+		iterator begin() { return iterator(m_data); }
+		iterator end() { return iterator(m_data + m_size); }
+		const_iterator begin() const { return const_iterator(m_data); }
+		const_iterator end() const { return const_iterator(m_data + m_size); }
 
 		void pop_back();
 		void remove(size_type);
@@ -54,6 +53,9 @@ namespace BAN
 
 		bool contains(const T&) const;
 
+		Span<T> span() { return Span(m_data, m_size); }
+		const Span<T> span() const { return Span(m_data, m_size); }
+
 		const T& operator[](size_type) const;
 		T& operator[](size_type);
 
@@ -62,7 +64,7 @@ namespace BAN
 		const T& front() const;
 		T& front();
 
-		ErrorOr<void> resize(size_type);
+		ErrorOr<void> resize(size_type, const T& = T());
 		ErrorOr<void> reserve(size_type);
 		ErrorOr<void> shrink_to_fit();
 
@@ -79,51 +81,6 @@ namespace BAN
 		size_type	m_size		= 0;
 	};
 
-	template<typename T, bool CONST>
-	class VectorIterator
-	{
-	public:
-		using value_type = T;
-		using data_type = maybe_const_t<CONST, T>;
-
-	public:
-		VectorIterator() = default;
-		template<bool C>
-		VectorIterator(const VectorIterator<T, C>& other, enable_if_t<C == CONST || !C>)
-			: m_data(other.m_data)
-		{
-		}
-		
-		VectorIterator<T, CONST>& operator++()		{ m_data++; return *this; }
-		VectorIterator<T, CONST>& operator--()		{ m_data--; return *this; }
-		VectorIterator<T, CONST> operator++(int)	{ auto temp = *this; ++(*this); return temp; }
-		VectorIterator<T, CONST> operator--(int)	{ auto temp = *this; --(*this); return temp; }
-
-		template<bool ENABLE = !CONST>
-		enable_if_t<ENABLE, T&> operator*()		{ ASSERT(m_data); return *m_data; }
-		const T& operator*() const				{ ASSERT(m_data); return *m_data; }
-
-		template<bool ENABLE = !CONST>
-		enable_if_t<ENABLE, T*> operator->()	{ ASSERT(m_data); return m_data; }
-		const T* operator->() const				{ ASSERT(m_data); return m_data; }
-
-		bool operator==(const VectorIterator<T, CONST>& other) const { return m_data == other.m_data; }
-		bool operator!=(const VectorIterator<T, CONST>& other) const { return !(*this == other); }
-
-		operator bool() const { return m_data; }
-
-	private:
-		VectorIterator(data_type* data) : m_data(data) { }
-
-	private:
-		data_type* m_data = nullptr;
-
-		friend class Vector<T>;
-		friend class VectorIterator<T, !CONST>;
-	};
-
-
-
 	template<typename T>
 	Vector<T>::Vector(Vector<T>&& other)
 	{
@@ -256,7 +213,7 @@ namespace BAN
 	template<typename T>
 	ErrorOr<void> Vector<T>::insert(size_type index, const T& value)
 	{
-		return insert(move(T(value)), index);
+		return insert(index, move(T(value)));
 	}
 
 	template<typename T>
@@ -340,7 +297,7 @@ namespace BAN
 	}
 
 	template<typename T>
-	ErrorOr<void> Vector<T>::resize(size_type size)
+	ErrorOr<void> Vector<T>::resize(size_type size, const T& value)
 	{
 		TRY(ensure_capacity(size));
 		if (size < m_size)
@@ -348,7 +305,7 @@ namespace BAN
 				m_data[i].~T();
 		if (size > m_size)
 			for (size_type i = m_size; i < size; i++)
-				new (m_data + i) T();
+				new (m_data + i) T(value);
 		m_size = size;
 		return {};
 	}

BAN/include/BAN/WeakPtr.h

@@ -0,0 +1,107 @@
+#pragma once
+
+#include <BAN/RefPtr.h>
+
+namespace BAN
+{
+
+	template<typename T>
+	class Weakable;
+
+	template<typename T>
+	class WeakPtr;
+
+	template<typename T>
+	class WeakLink : public RefCounted<WeakLink<T>>
+	{
+	public:
+		RefPtr<T> lock() { ASSERT(m_ptr); return raw_ptr(); }
+		T* raw_ptr() { return m_ptr; }
+
+		bool valid() const { return m_ptr; }
+		void invalidate() { m_ptr = nullptr; }
+
+	private:
+		WeakLink(T* ptr) : m_ptr(ptr) {}
+
+	private:
+		T* m_ptr;
+
+		friend class RefPtr<WeakLink<T>>;
+	};
+
+	template<typename T>
+	class Weakable
+	{
+	public:
+		~Weakable()
+		{
+			if (m_link)
+				m_link->invalidate();
+		}
+
+		ErrorOr<WeakPtr<T>> get_weak_ptr() const
+		{
+			if (!m_link)
+				m_link = TRY(RefPtr<WeakLink<T>>::create((T*)this));
+			return WeakPtr<T>(m_link);
+		}
+
+	private:
+		mutable RefPtr<WeakLink<T>> m_link;
+	};
+
+	template<typename T>
+	class WeakPtr
+	{
+	public:
+		WeakPtr() = default;
+		WeakPtr(WeakPtr&& other)		{ *this = move(other); }
+		WeakPtr(const WeakPtr& other)	{ *this = other; }
+		WeakPtr(const RefPtr<T>& other)	{ *this = other; }
+
+		WeakPtr& operator=(WeakPtr&& other)
+		{
+			clear();
+			m_link = move(other.m_link);
+			return *this;
+		}
+		WeakPtr& operator=(const WeakPtr& other)
+		{
+			clear();
+			m_link = other.m_link;
+			return *this;
+		}
+		WeakPtr& operator=(const RefPtr<T>& other)
+		{
+			clear();
+			if (other)
+				m_link = MUST(other->get_weak_ptr()).move_link();
+			return *this;
+		}
+
+		RefPtr<T> lock()
+		{
+			if (m_link->valid())
+				return m_link->lock();
+			return nullptr;
+		}
+
+		void clear() { m_link.clear(); }
+
+		bool valid() const { return m_link && m_link->valid(); }
+
+	private:
+		WeakPtr(const RefPtr<WeakLink<T>>& link)
+			: m_link(link)
+		{ }
+
+		RefPtr<WeakLink<T>>&& move_link() { return move(m_link); }
+
+	private:
+		RefPtr<WeakLink<T>> m_link;
+
+		friend class Weakable<T>;
+	};
+
+}

CMakeLists.txt

@@ -0,0 +1,44 @@
+cmake_minimum_required(VERSION 3.26)
+
+if (NOT ${CMAKE_SYSTEM_NAME} STREQUAL "banan-os")
+	message(FATAL_ERROR "CMAKE_SYSTEM_NAME is not banan-os")
+endif ()
+
+add_compile_options(-mno-sse -mno-sse2)
+add_compile_definitions(__enable_sse=0)
+
+project(banan-os CXX C ASM)
+
+set(BANAN_BASE_SYSROOT ${CMAKE_SOURCE_DIR}/base-sysroot.tar.gz)
+set(BANAN_INCLUDE ${BANAN_SYSROOT}/usr/include)
+set(BANAN_LIB ${BANAN_SYSROOT}/usr/lib)
+set(BANAN_BIN ${BANAN_SYSROOT}/usr/bin)
+set(BANAN_BOOT ${BANAN_SYSROOT}/boot)
+
+add_subdirectory(kernel)
+add_subdirectory(bootloader)
+add_subdirectory(BAN)
+add_subdirectory(libc)
+add_subdirectory(LibELF)
+add_subdirectory(userspace)
+
+add_custom_target(sysroot
+	COMMAND ${CMAKE_COMMAND} -E make_directory ${BANAN_SYSROOT}
+	COMMAND cd ${BANAN_SYSROOT} && tar xf ${BANAN_BASE_SYSROOT}
+)
+
+add_custom_target(headers
+	DEPENDS kernel-headers
+	DEPENDS ban-headers
+	DEPENDS libc-headers
+	DEPENDS libelf-headers
+)
+
+add_custom_target(install-sysroot
+	COMMAND cd ${BANAN_SYSROOT} && tar cf ${BANAN_SYSROOT_TAR} *
+	DEPENDS kernel-install
+	DEPENDS ban-install
+	DEPENDS libc-install
+	DEPENDS userspace-install
+	DEPENDS libelf-install
+)

LICENCE

@@ -0,0 +1,24 @@
+BSD 2-Clause License
+
+Copyright (c) 2023, Oskari Alaranta
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

LibELF/CMakeLists.txt

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(LibELF CXX)
+
+add_custom_target(libelf-headers
+	COMMAND ${CMAKE_COMMAND} -E copy_directory_if_different ${CMAKE_CURRENT_SOURCE_DIR}/include/ ${BANAN_INCLUDE}/
+	DEPENDS sysroot
+)
+
+add_custom_target(libelf-install
+	DEPENDS libelf-headers
+)

LibELF/LibELF/ELF.cpp

@@ -0,0 +1,406 @@
+#include <BAN/ScopeGuard.h>
+#include <LibELF/ELF.h>
+#include <LibELF/Values.h>
+
+#ifdef __is_kernel
+#include <kernel/FS/VirtualFileSystem.h>
+#include <kernel/Memory/PageTableScope.h>
+#include <kernel/Process.h>
+#endif
+
+#include <fcntl.h>
+
+#define ELF_PRINT_HEADERS 0
+
+#ifdef __is_kernel
+extern uint8_t g_kernel_end[];
+using namespace Kernel;
+#endif
+
+namespace LibELF
+{
+
+#ifdef __is_kernel
+	BAN::ErrorOr<BAN::UniqPtr<ELF>> ELF::load_from_file(BAN::RefPtr<Inode> inode)
+	{
+		BAN::Vector<uint8_t> buffer;
+		TRY(buffer.resize(inode->size()));
+
+		TRY(inode->read(0, buffer.data(), inode->size()));
+
+		ELF* elf_ptr = new ELF(BAN::move(buffer));
+		if (elf_ptr == nullptr)
+			return BAN::Error::from_errno(ENOMEM);
+
+		auto elf = BAN::UniqPtr<ELF>::adopt(elf_ptr);
+		TRY(elf->load());
+
+		return BAN::move(elf);
+	}
+#else
+	BAN::ErrorOr<ELF*> ELF::load_from_file(BAN::StringView file_path)
+	{
+		ELF* elf = nullptr;
+
+		{
+			BAN::Vector<uint8_t> data;
+
+			int fd = TRY(Kernel::Process::current().open(file_path, O_RDONLY));
+			BAN::ScopeGuard _([fd] { MUST(Kernel::Process::current().close(fd)); });
+
+			struct stat st;
+			TRY(Kernel::Process::current().fstat(fd, &st));
+
+			TRY(data.resize(st.st_size));
+
+			TRY(Kernel::Process::current().read(fd, data.data(), data.size()));
+
+			elf = new ELF(BAN::move(data));
+			ASSERT(elf);
+		}
+
+		if (auto res = elf->load(); res.is_error())
+		{
+			delete elf;
+			return res.error();
+		}
+
+		return elf;
+	}
+#endif
+
+	BAN::ErrorOr<void> ELF::load()
+	{
+		if (m_data.size() < EI_NIDENT)
+		{
+			dprintln("Too small ELF file");
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		if (m_data[EI_MAG0] != ELFMAG0 || 
+			m_data[EI_MAG1] != ELFMAG1 ||
+			m_data[EI_MAG2] != ELFMAG2 ||
+			m_data[EI_MAG3] != ELFMAG3)
+		{
+			dprintln("Invalid ELF header");
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		if (m_data[EI_DATA] != ELFDATA2LSB)
+		{
+			dprintln("Only little-endian is supported");
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		if (m_data[EI_VERSION] != EV_CURRENT)
+		{
+			dprintln("Invalid ELF version");
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		if (m_data[EI_CLASS] == ELFCLASS64)
+		{
+			if (m_data.size() <= sizeof(Elf64FileHeader))
+			{
+				dprintln("Too small ELF file");
+				return BAN::Error::from_errno(EINVAL);
+			}
+
+			auto& header = file_header64();
+			if (!parse_elf64_file_header(header))
+				return BAN::Error::from_errno(EINVAL);
+
+			for (size_t i = 0; i < header.e_phnum; i++)
+			{
+				auto& program_header = program_header64(i);
+				if (!parse_elf64_program_header(program_header))
+					return BAN::Error::from_errno(EINVAL);
+			}
+
+			for (size_t i = 1; i < header.e_shnum; i++)
+			{
+				auto& section_header = section_header64(i);
+				if (!parse_elf64_section_header(section_header))
+					return BAN::Error::from_errno(EINVAL);
+			}
+		}
+		else if (m_data[EI_CLASS] == ELFCLASS32)
+		{
+			if (m_data.size() <= sizeof(Elf32FileHeader))
+			{
+				dprintln("Too small ELF file");
+				return BAN::Error::from_errno(EINVAL);
+			}
+
+			auto& header = file_header32();
+			if (!parse_elf32_file_header(header))
+				return BAN::Error::from_errno(EINVAL);
+
+			for (size_t i = 0; i < header.e_phnum; i++)
+			{
+				auto& program_header = program_header32(i);
+				if (!parse_elf32_program_header(program_header))
+					return BAN::Error::from_errno(EINVAL);
+			}
+
+			for (size_t i = 1; i < header.e_shnum; i++)
+			{
+				auto& section_header = section_header32(i);
+				if (!parse_elf32_section_header(section_header))
+					return BAN::Error::from_errno(EINVAL);
+			}
+		}
+
+		return {};
+	}
+
+	bool ELF::is_x86_32() const { return m_data[EI_CLASS] == ELFCLASS32; }
+	bool ELF::is_x86_64() const { return m_data[EI_CLASS] == ELFCLASS64; }
+
+	/*
+
+		64 bit ELF
+
+	*/
+
+	const char* ELF::lookup_section_name64(uint32_t offset) const
+	{
+		return lookup_string64(file_header64().e_shstrndx, offset);
+	}
+
+	const char* ELF::lookup_string64(size_t table_index, uint32_t offset) const
+	{
+		if (table_index == SHN_UNDEF)
+			return nullptr;
+		auto& section_header = section_header64(table_index);
+		return (const char*)m_data.data() + section_header.sh_offset + offset;
+	}
+
+	bool ELF::parse_elf64_file_header(const Elf64FileHeader& header)
+	{
+		if (header.e_type != ET_EXEC)
+		{
+			dprintln("Only executable files are supported");
+			return false;
+		}
+
+		if (header.e_version != EV_CURRENT)
+		{
+			dprintln("Invalid ELF version");
+			return false;
+		}
+
+		return true;
+	}
+
+	bool ELF::parse_elf64_program_header(const Elf64ProgramHeader& header)
+	{
+#if ELF_PRINT_HEADERS
+		dprintln("program header");
+		dprintln("  type   {H}", header.p_type);
+		dprintln("  flags  {H}", header.p_flags);
+		dprintln("  offset {H}", header.p_offset);
+		dprintln("  vaddr  {H}", header.p_vaddr);
+		dprintln("  paddr  {H}", header.p_paddr);
+		dprintln("  filesz {}", header.p_filesz);
+		dprintln("  memsz  {}", header.p_memsz);
+		dprintln("  align  {}", header.p_align);
+#endif
+		(void)header;
+		return true;
+	}
+
+	bool ELF::parse_elf64_section_header(const Elf64SectionHeader& header)
+	{
+#if ELF_PRINT_HEADERS
+		if (auto* name = lookup_section_name64(header.sh_name))
+			dprintln("{}", name);
+
+		switch (header.sh_type)
+		{
+			case SHT_NULL:
+				dprintln("  SHT_NULL");
+				break;
+			case SHT_PROGBITS:
+				dprintln("  SHT_PROGBITS");
+				break;
+			case SHT_SYMTAB:
+				for (size_t i = 1; i < header.sh_size / header.sh_entsize; i++)
+				{
+					auto& symbol = ((const Elf64Symbol*)(m_data.data() + header.sh_offset))[i];
+					if (auto* name = lookup_string64(header.sh_link, symbol.st_name))
+						dprintln("  {}", name);
+				}
+				break;
+			case SHT_STRTAB:
+				dprintln("  SHT_STRTAB");
+				break;
+			case SHT_RELA:
+				dprintln("  SHT_RELA");
+				break;
+			case SHT_NOBITS:
+				dprintln("  SHT_NOBITS");
+				break;
+			case SHT_REL:
+				dprintln("  SHT_REL");
+				break;
+			case SHT_SHLIB:
+				dprintln("  SHT_SHLIB");
+				break;
+			case SHT_DYNSYM:
+				dprintln("  SHT_DYNSYM");
+				break;
+			default:
+				ASSERT(false);
+		}	
+#endif
+		(void)header;
+		return true;
+	}
+
+	const Elf64FileHeader& ELF::file_header64() const
+	{
+		ASSERT(is_x86_64());
+		return *(const Elf64FileHeader*)m_data.data();
+	}
+
+	const Elf64ProgramHeader& ELF::program_header64(size_t index) const
+	{
+		ASSERT(is_x86_64());
+		const auto& file_header = file_header64();
+		ASSERT(index < file_header.e_phnum);
+		return *(const Elf64ProgramHeader*)(m_data.data() + file_header.e_phoff + file_header.e_phentsize * index);
+	}
+
+	const Elf64SectionHeader& ELF::section_header64(size_t index) const
+	{
+		ASSERT(is_x86_64());
+		const auto& file_header = file_header64();
+		ASSERT(index < file_header.e_shnum);
+		return *(const Elf64SectionHeader*)(m_data.data() + file_header.e_shoff + file_header.e_shentsize * index);
+	}
+
+	/*
+
+		32 bit ELF
+
+	*/
+
+	const char* ELF::lookup_section_name32(uint32_t offset) const
+	{
+		return lookup_string32(file_header32().e_shstrndx, offset);
+	}
+
+	const char* ELF::lookup_string32(size_t table_index, uint32_t offset) const
+	{
+		if (table_index == SHN_UNDEF)
+			return nullptr;
+		auto& section_header = section_header32(table_index);
+		return (const char*)m_data.data() + section_header.sh_offset + offset;
+	}
+
+	bool ELF::parse_elf32_file_header(const Elf32FileHeader& header)
+	{
+		if (header.e_type != ET_EXEC)
+		{
+			dprintln("Only executable files are supported");
+			return false;
+		}
+
+		if (header.e_version != EV_CURRENT)
+		{
+			dprintln("Invalid ELF version");
+			return false;
+		}
+
+		return true;
+	}
+
+	bool ELF::parse_elf32_program_header(const Elf32ProgramHeader& header)
+	{
+#if ELF_PRINT_HEADERS
+		dprintln("program header");
+		dprintln("  type   {H}", header.p_type);
+		dprintln("  flags  {H}", header.p_flags);
+		dprintln("  offset {H}", header.p_offset);
+		dprintln("  vaddr  {H}", header.p_vaddr);
+		dprintln("  paddr  {H}", header.p_paddr);
+		dprintln("  filesz {}", header.p_filesz);
+		dprintln("  memsz  {}", header.p_memsz);
+		dprintln("  align  {}", header.p_align);
+#endif
+		(void)header;
+		return true;
+	}
+
+	bool ELF::parse_elf32_section_header(const Elf32SectionHeader& header)
+	{
+#if ELF_PRINT_HEADERS
+		if (auto* name = lookup_section_name32(header.sh_name))
+			dprintln("{}", name);
+
+		switch (header.sh_type)
+		{
+			case SHT_NULL:
+				dprintln("  SHT_NULL");
+				break;
+			case SHT_PROGBITS:
+				dprintln("  SHT_PROGBITS");
+				break;
+			case SHT_SYMTAB:
+				for (size_t i = 1; i < header.sh_size / header.sh_entsize; i++)
+				{
+					auto& symbol = ((const Elf32Symbol*)(m_data.data() + header.sh_offset))[i];
+					if (auto* name = lookup_string32(header.sh_link, symbol.st_name))
+						dprintln("  {}", name);
+				}
+				break;
+			case SHT_STRTAB:
+				dprintln("  SHT_STRTAB");
+				break;
+			case SHT_RELA:
+				dprintln("  SHT_RELA");
+				break;
+			case SHT_NOBITS:
+				dprintln("  SHT_NOBITS");
+				break;
+			case SHT_REL:
+				dprintln("  SHT_REL");
+				break;
+			case SHT_SHLIB:
+				dprintln("  SHT_SHLIB");
+				break;
+			case SHT_DYNSYM:
+				dprintln("  SHT_DYNSYM");
+				break;
+			default:
+				ASSERT(false);
+		}	
+#endif
+		(void)header;
+		return true;
+	}
+
+	const Elf32FileHeader& ELF::file_header32() const
+	{
+		ASSERT(is_x86_32());
+		return *(const Elf32FileHeader*)m_data.data();
+	}
+
+	const Elf32ProgramHeader& ELF::program_header32(size_t index) const
+	{
+		ASSERT(is_x86_32());
+		const auto& file_header = file_header32();
+		ASSERT(index < file_header.e_phnum);
+		return *(const Elf32ProgramHeader*)(m_data.data() + file_header.e_phoff + file_header.e_phentsize * index);
+	}
+
+	const Elf32SectionHeader& ELF::section_header32(size_t index) const
+	{
+		ASSERT(is_x86_32());
+		const auto& file_header = file_header32();
+		ASSERT(index < file_header.e_shnum);
+		return *(const Elf32SectionHeader*)(m_data.data() + file_header.e_shoff + file_header.e_shentsize * index);
+	}
+
+}

LibELF/LibELF/LoadableELF.cpp

@@ -0,0 +1,331 @@
+#include <BAN/ScopeGuard.h>
+#include <kernel/CriticalScope.h>
+#include <kernel/Memory/Heap.h>
+#include <kernel/LockGuard.h>
+#include <LibELF/LoadableELF.h>
+#include <LibELF/Values.h>
+
+namespace LibELF
+{
+
+	using namespace Kernel;
+
+	BAN::ErrorOr<BAN::UniqPtr<LoadableELF>> LoadableELF::load_from_inode(PageTable& page_table, BAN::RefPtr<Inode> inode)
+	{
+		auto* elf_ptr = new LoadableELF(page_table, inode);
+		if (elf_ptr == nullptr)
+			return BAN::Error::from_errno(ENOMEM);
+		auto elf = BAN::UniqPtr<LoadableELF>::adopt(elf_ptr);
+		TRY(elf->initialize());
+		return BAN::move(elf);
+	}
+
+	LoadableELF::LoadableELF(PageTable& page_table, BAN::RefPtr<Inode> inode)
+		: m_inode(inode)
+		, m_page_table(page_table)
+	{
+	}
+
+	LoadableELF::~LoadableELF()
+	{
+		if (!m_loaded)
+			return;
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					continue;
+				case PT_LOAD:
+				{
+					vaddr_t start = program_header.p_vaddr & PAGE_ADDR_MASK;
+					size_t pages = range_page_count(program_header.p_vaddr, program_header.p_memsz);
+					for (size_t i = 0; i < pages; i++)
+					{
+						paddr_t paddr = m_page_table.physical_address_of(start + i * PAGE_SIZE);
+						if (paddr != 0)
+							Heap::get().release_page(paddr);
+					}
+					m_page_table.unmap_range(start, pages * PAGE_SIZE);
+					break;
+				}
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+	}
+
+	BAN::ErrorOr<void> LoadableELF::initialize()
+	{
+		if ((size_t)m_inode->size() < sizeof(ElfNativeFileHeader))
+		{
+			dprintln("Too small file");
+			return BAN::Error::from_errno(ENOEXEC);
+		}
+
+		size_t nread = TRY(m_inode->read(0, BAN::ByteSpan::from(m_file_header)));
+		ASSERT(nread == sizeof(m_file_header));
+
+		if (m_file_header.e_ident[EI_MAG0] != ELFMAG0 || 
+			m_file_header.e_ident[EI_MAG1] != ELFMAG1 ||
+			m_file_header.e_ident[EI_MAG2] != ELFMAG2 ||
+			m_file_header.e_ident[EI_MAG3] != ELFMAG3)
+		{
+			dprintln("Invalid magic in header");
+			return BAN::Error::from_errno(ENOEXEC);
+		}
+
+		if (m_file_header.e_ident[EI_DATA] != ELFDATA2LSB)
+		{
+			dprintln("Only little-endian is supported");
+			return BAN::Error::from_errno(ENOEXEC);
+		}
+
+		if (m_file_header.e_ident[EI_VERSION] != EV_CURRENT)
+		{
+			dprintln("Invalid version");
+			return BAN::Error::from_errno(ENOEXEC);
+		}
+
+#if ARCH(i386)
+		if (m_file_header.e_ident[EI_CLASS] != ELFCLASS32)
+#elif ARCH(x86_64)
+		if (m_file_header.e_ident[EI_CLASS] != ELFCLASS64)
+#endif
+		{
+			dprintln("Not in native format");	
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		if (m_file_header.e_type != ET_EXEC)
+		{
+			dprintln("Only executable files are supported");
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		if (m_file_header.e_version != EV_CURRENT)
+		{
+			dprintln("Unsupported version");
+			return BAN::Error::from_errno(EINVAL);
+		}
+
+		ASSERT(m_file_header.e_phentsize <= sizeof(ElfNativeProgramHeader));
+
+		TRY(m_program_headers.resize(m_file_header.e_phnum));
+		for (size_t i = 0; i < m_file_header.e_phnum; i++)
+		{
+			TRY(m_inode->read(m_file_header.e_phoff + m_file_header.e_phentsize * i, BAN::ByteSpan::from(m_program_headers[i])));
+
+			const auto& pheader = m_program_headers[i];
+			if (pheader.p_type != PT_NULL && pheader.p_type != PT_LOAD)
+			{
+				dprintln("Unsupported program header type {}", pheader.p_type);
+				return BAN::Error::from_errno(ENOTSUP);
+			}
+			if (pheader.p_memsz < pheader.p_filesz)
+			{
+				dprintln("Invalid program header");
+				return BAN::Error::from_errno(EINVAL);
+			}
+
+			m_virtual_page_count += BAN::Math::div_round_up<size_t>((pheader.p_vaddr % PAGE_SIZE) + pheader.p_memsz, PAGE_SIZE);
+		}
+
+		return {};
+	}
+
+	vaddr_t LoadableELF::entry_point() const
+	{
+		return m_file_header.e_entry;
+	}
+
+	bool LoadableELF::contains(vaddr_t address) const
+	{
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					continue;
+				case PT_LOAD:
+					if (program_header.p_vaddr <= address && address < program_header.p_vaddr + program_header.p_memsz)
+						return true;
+					break;
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+		return false;
+	}
+
+	bool LoadableELF::is_address_space_free() const
+	{
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					break;
+				case PT_LOAD:
+				{
+					vaddr_t page_vaddr = program_header.p_vaddr & PAGE_ADDR_MASK;
+					size_t pages = range_page_count(program_header.p_vaddr, program_header.p_memsz);
+					if (!m_page_table.is_range_free(page_vaddr, pages * PAGE_SIZE))
+						return false;
+					break;
+				}
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+		return true;
+	}
+
+	void LoadableELF::reserve_address_space()
+	{
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					break;
+				case PT_LOAD:
+				{
+					vaddr_t page_vaddr = program_header.p_vaddr & PAGE_ADDR_MASK;
+					size_t pages = range_page_count(program_header.p_vaddr, program_header.p_memsz);
+					ASSERT(m_page_table.reserve_range(page_vaddr, pages * PAGE_SIZE));
+					break;
+				}
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+		m_loaded = true;
+	}
+
+	BAN::ErrorOr<void> LoadableELF::load_page_to_memory(vaddr_t address)
+	{
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					break;
+				case PT_LOAD:
+				{
+					if (!(program_header.p_vaddr <= address && address < program_header.p_vaddr + program_header.p_memsz))
+						continue;
+
+					PageTable::flags_t flags = PageTable::Flags::UserSupervisor | PageTable::Flags::Present;
+					if (program_header.p_flags & LibELF::PF_W)
+						flags |= PageTable::Flags::ReadWrite;
+					if (program_header.p_flags & LibELF::PF_X)
+						flags |= PageTable::Flags::Execute;
+
+					vaddr_t vaddr = address & PAGE_ADDR_MASK;
+					paddr_t paddr = Heap::get().take_free_page();
+					if (paddr == 0)
+						return BAN::Error::from_errno(ENOMEM);
+
+					// Temporarily map page as RW so kernel can write to it
+					m_page_table.map_page_at(paddr, vaddr, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
+					m_physical_page_count++;
+
+					memset((void*)vaddr, 0x00, PAGE_SIZE);
+					
+					if (vaddr / PAGE_SIZE < BAN::Math::div_round_up<size_t>(program_header.p_vaddr + program_header.p_filesz, PAGE_SIZE))
+					{
+						size_t vaddr_offset = 0;
+						if (vaddr < program_header.p_vaddr)
+							vaddr_offset = program_header.p_vaddr - vaddr;
+						
+						size_t file_offset = 0;
+						if (vaddr > program_header.p_vaddr)
+							file_offset = vaddr - program_header.p_vaddr;
+
+						size_t bytes = BAN::Math::min<size_t>(PAGE_SIZE - vaddr_offset, program_header.p_filesz - file_offset);
+						TRY(m_inode->read(program_header.p_offset + file_offset, { (uint8_t*)vaddr + vaddr_offset, bytes }));
+					}
+
+					// Map page with the correct flags
+					m_page_table.map_page_at(paddr, vaddr, flags);
+
+					return {};
+				}
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+		ASSERT_NOT_REACHED();
+	}
+
+	
+	BAN::ErrorOr<BAN::UniqPtr<LoadableELF>> LoadableELF::clone(Kernel::PageTable& new_page_table)
+	{
+		auto* elf_ptr = new LoadableELF(new_page_table, m_inode);
+		if (elf_ptr == nullptr)
+			return BAN::Error::from_errno(ENOMEM);
+		auto elf = BAN::UniqPtr<LoadableELF>::adopt(elf_ptr);
+
+		memcpy(&elf->m_file_header, &m_file_header, sizeof(ElfNativeFileHeader));
+
+		TRY(elf->m_program_headers.resize(m_program_headers.size()));
+		memcpy(elf->m_program_headers.data(), m_program_headers.data(), m_program_headers.size() * sizeof(ElfNativeProgramHeader));
+
+		elf->reserve_address_space();
+
+		ASSERT(&PageTable::current() == &m_page_table);
+		LockGuard _(m_page_table);
+		ASSERT(m_page_table.is_page_free(0));
+
+		for (const auto& program_header : m_program_headers)
+		{
+			switch (program_header.p_type)
+			{
+				case PT_NULL:
+					break;
+				case PT_LOAD:
+				{
+					if (!(program_header.p_flags & LibELF::PF_W))
+						continue;
+
+					PageTable::flags_t flags = PageTable::Flags::UserSupervisor | PageTable::Flags::Present;
+					if (program_header.p_flags & LibELF::PF_W)
+						flags |= PageTable::Flags::ReadWrite;
+					if (program_header.p_flags & LibELF::PF_X)
+						flags |= PageTable::Flags::Execute;
+
+					vaddr_t start = program_header.p_vaddr & PAGE_ADDR_MASK;
+					size_t pages = range_page_count(program_header.p_vaddr, program_header.p_memsz);
+
+					for (size_t i = 0; i < pages; i++)
+					{
+						if (m_page_table.physical_address_of(start + i * PAGE_SIZE) == 0)
+							continue;
+
+						paddr_t paddr = Heap::get().take_free_page();
+						if (paddr == 0)
+							return BAN::Error::from_errno(ENOMEM);
+
+						{
+							CriticalScope _;
+							PageTable::map_fast_page(paddr);
+							memcpy(PageTable::fast_page_as_ptr(), (void*)(start + i * PAGE_SIZE), PAGE_SIZE);
+							PageTable::unmap_fast_page();
+						}
+
+						new_page_table.map_page_at(paddr, start + i * PAGE_SIZE, flags);
+						elf->m_physical_page_count++;
+					}
+
+					break;
+				}
+				default:
+					ASSERT_NOT_REACHED();
+			}
+		}
+
+		return elf;
+	}
+
+}

LibELF/include/LibELF/ELF.h

@@ -0,0 +1,89 @@
+#pragma once
+
+#ifdef __is_kernel
+#include <kernel/FS/Inode.h>
+#include <kernel/Memory/VirtualRange.h>
+#endif
+
+#include <BAN/StringView.h>
+#include <BAN/UniqPtr.h>
+#include <BAN/Vector.h>
+#include <kernel/Arch.h>
+#include "Types.h"
+
+namespace LibELF
+{
+
+	class ELF
+	{
+	public:
+#ifdef __is_kernel
+		static BAN::ErrorOr<BAN::UniqPtr<ELF>> load_from_file(BAN::RefPtr<Kernel::Inode>);
+#else
+		static BAN::ErrorOr<BAN::UniqPtr<ELF>> load_from_file(BAN::StringView);
+#endif
+
+		const Elf64FileHeader& file_header64() const;
+		const Elf64ProgramHeader& program_header64(size_t) const;
+		const Elf64SectionHeader& section_header64(size_t) const;
+		const char* lookup_section_name64(uint32_t) const;
+		const char* lookup_string64(size_t, uint32_t) const;
+#if ARCH(x86_64)
+		const Elf64FileHeader& file_header_native() const { return file_header64(); }
+		const Elf64ProgramHeader& program_header_native(size_t index) const { return program_header64(index); }
+		const Elf64SectionHeader& section_header_native(size_t index) const { return section_header64(index); }
+		const char* lookup_section_name_native(uint32_t offset) const { return lookup_section_name64(offset); }
+		const char* lookup_string_native(size_t table_index, uint32_t offset) const { return lookup_string64(table_index, offset); }
+		bool is_native() const { return is_x86_64(); }
+#endif
+
+		const Elf32FileHeader& file_header32() const;
+		const Elf32ProgramHeader& program_header32(size_t) const;
+		const Elf32SectionHeader& section_header32(size_t) const;
+		const char* lookup_section_name32(uint32_t) const;
+		const char* lookup_string32(size_t, uint32_t) const;
+#if ARCH(i386)
+		const Elf32FileHeader& file_header_native() const { return file_header32(); }
+		const Elf32ProgramHeader& program_header_native(size_t index) const { return program_header32(index); }
+		const Elf32SectionHeader& section_header_native(size_t index) const { return section_header32(index); }
+		const char* lookup_section_name_native(uint32_t offset) const { return lookup_section_name32(offset); }
+		const char* lookup_string_native(size_t table_index, uint32_t offset) const { return lookup_string32(table_index, offset); }
+		bool is_native() const { return is_x86_32(); }
+#endif
+
+		const uint8_t* data() const { return m_data.data(); }
+
+		bool is_x86_32() const;
+		bool is_x86_64() const;
+
+	private:
+//#ifdef __is_kernel
+//		ELF(BAN::UniqPtr<Kernel::VirtualRange>&& storage, size_t size)
+//			: m_storage(BAN::move(storage))
+//			, m_data((const uint8_t*)m_storage->vaddr(), size)
+//		{}
+//#else
+		ELF(BAN::Vector<uint8_t>&& data)
+			: m_data(BAN::move(data))
+		{}
+//#endif
+		BAN::ErrorOr<void> load();
+		
+		bool parse_elf64_file_header(const Elf64FileHeader&);
+		bool parse_elf64_program_header(const Elf64ProgramHeader&);
+		bool parse_elf64_section_header(const Elf64SectionHeader&);
+
+		bool parse_elf32_file_header(const Elf32FileHeader&);
+		bool parse_elf32_program_header(const Elf32ProgramHeader&);
+		bool parse_elf32_section_header(const Elf32SectionHeader&);
+
+	private:
+//#ifdef __is_kernel
+//		BAN::UniqPtr<Kernel::VirtualRange> m_storage;
+//		BAN::Span<const uint8_t> m_data;
+//#else
+		const BAN::Vector<uint8_t> m_data;
+//#endif
+	};
+
+}

LibELF/include/LibELF/LoadableELF.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#ifndef __is_kernel
+#error "This is kernel only header"
+#endif
+
+#include <BAN/UniqPtr.h>
+#include <BAN/Vector.h>
+
+#include <kernel/FS/Inode.h>
+#include <kernel/Memory/PageTable.h>
+
+#include <LibELF/Types.h>
+
+namespace LibELF
+{
+
+	class LoadableELF
+	{
+		BAN_NON_COPYABLE(LoadableELF);
+		BAN_NON_MOVABLE(LoadableELF);
+
+	public:
+		static BAN::ErrorOr<BAN::UniqPtr<LoadableELF>> load_from_inode(Kernel::PageTable&, BAN::RefPtr<Kernel::Inode>);
+		~LoadableELF();
+
+		Kernel::vaddr_t entry_point() const;
+
+		bool contains(Kernel::vaddr_t address) const;
+		bool is_address_space_free() const;
+		void reserve_address_space();
+
+		BAN::ErrorOr<void> load_page_to_memory(Kernel::vaddr_t address);
+
+		BAN::ErrorOr<BAN::UniqPtr<LoadableELF>> clone(Kernel::PageTable&);
+
+		size_t virtual_page_count() const { return m_virtual_page_count; }
+		size_t physical_page_count() const { return m_physical_page_count; }
+
+	private:
+		LoadableELF(Kernel::PageTable&, BAN::RefPtr<Kernel::Inode>);
+		BAN::ErrorOr<void> initialize();
+
+	private:
+		BAN::RefPtr<Kernel::Inode>			m_inode;
+		Kernel::PageTable&					m_page_table;
+		ElfNativeFileHeader					m_file_header;
+		BAN::Vector<ElfNativeProgramHeader>	m_program_headers;
+		size_t m_virtual_page_count = 0;
+		size_t m_physical_page_count = 0;
+		bool m_loaded { false };
+	};
+
+}

LibELF/include/LibELF/Types.h

@@ -0,0 +1,186 @@
+#pragma once
+
+#include <kernel/Arch.h>
+
+#include <stdint.h>
+
+namespace LibELF
+{
+
+	using Elf32Addr = uint32_t;
+	using Elf32Off = uint32_t;
+	using Elf32Half = uint16_t;
+	using Elf32Word = uint32_t;
+	using Elf32Sword = int32_t;
+
+	struct Elf32FileHeader
+	{
+		unsigned char e_ident[16];
+		Elf32Half e_type;
+		Elf32Half e_machine;
+		Elf32Word e_version;
+		Elf32Addr e_entry;
+		Elf32Off e_phoff;
+		Elf32Off e_shoff;
+		Elf32Word e_flags;
+		Elf32Half e_ehsize;
+		Elf32Half e_phentsize;
+		Elf32Half e_phnum;
+		Elf32Half e_shentsize;
+		Elf32Half e_shnum;
+		Elf32Half e_shstrndx;
+	};
+
+	struct Elf32SectionHeader
+	{
+		Elf32Word sh_name;
+		Elf32Word sh_type;
+		Elf32Word sh_flags;
+		Elf32Addr sh_addr;
+		Elf32Off sh_offset;
+		Elf32Word sh_size;
+		Elf32Word sh_link;
+		Elf32Word sh_info;
+		Elf32Word sh_addralign;
+		Elf32Word sh_entsize;
+	};
+
+	struct Elf32Symbol
+	{
+		Elf32Word st_name;
+		Elf32Addr st_value;
+		Elf32Word st_size;
+		unsigned char st_info;
+		unsigned char st_other;
+		Elf32Half st_shndx;
+	};
+
+	struct Elf32Relocation
+	{
+		Elf32Addr r_offset;
+		Elf32Word r_info;
+	};
+
+	struct Elf32RelocationA
+	{
+		Elf32Addr r_offset;
+		Elf32Word r_info;
+		Elf32Sword r_addend;
+	};
+
+	struct Elf32ProgramHeader
+	{
+		Elf32Word p_type;
+		Elf32Off p_offset;
+		Elf32Addr p_vaddr;
+		Elf32Addr p_paddr;
+		Elf32Word p_filesz;
+		Elf32Word p_memsz;
+		Elf32Word p_flags;
+		Elf32Word p_align;
+	};
+
+	using Elf64Addr = uint64_t;
+	using Elf64Off = uint64_t;
+	using Elf64Half = uint16_t;
+	using Elf64Word = uint32_t;
+	using Elf64Sword = int32_t;
+	using Elf64Xword = uint64_t;
+	using Elf64Sxword = int64_t;
+
+	struct Elf64FileHeader
+	{
+		unsigned char e_ident[16];
+		Elf64Half e_type;
+		Elf64Half e_machine;
+		Elf64Word e_version;
+		Elf64Addr e_entry;
+		Elf64Off e_phoff;
+		Elf64Off e_shoff;
+		Elf64Word e_flags;
+		Elf64Half e_ehsize;
+		Elf64Half e_phentsize;
+		Elf64Half e_phnum;
+		Elf64Half e_shentsize;
+		Elf64Half e_shnum;
+		Elf64Half e_shstrndx;
+	};
+
+	struct Elf64SectionHeader
+	{
+		Elf64Word sh_name;
+		Elf64Word sh_type;
+		Elf64Xword sh_flags;
+		Elf64Addr sh_addr;
+		Elf64Off sh_offset;
+		Elf64Xword sh_size;
+		Elf64Word sh_link;
+		Elf64Word sh_info;
+		Elf64Xword sh_addralign;
+		Elf64Xword sh_entsize;
+	};
+
+	struct Elf64Symbol
+	{
+		Elf64Word st_name;
+		unsigned char st_info;
+		unsigned char st_other;
+		Elf64Half st_shndx;
+		Elf64Addr st_value;
+		Elf64Xword st_size;
+	};
+
+	struct Elf64Relocation
+	{
+		Elf64Addr r_offset;
+		Elf64Xword r_info;
+	};
+
+	struct Elf64RelocationA
+	{
+		Elf64Addr r_offset;
+		Elf64Xword r_info;
+		Elf64Sxword r_addend;
+	};
+
+	struct Elf64ProgramHeader
+	{
+		Elf64Word p_type;
+		Elf64Word p_flags;
+		Elf64Off p_offset;
+		Elf64Addr p_vaddr;
+		Elf64Addr p_paddr;
+		Elf64Xword p_filesz;
+		Elf64Xword p_memsz;
+		Elf64Xword p_align;
+	};
+
+#if ARCH(i386)
+	using ElfNativeAddr = Elf32Addr;
+	using ElfNativeOff = Elf32Off;
+	using ElfNativeHalf = Elf32Half;
+	using ElfNativeWord = Elf32Word;
+	using ElfNativeSword = Elf32Sword;
+	using ElfNativeFileHeader = Elf32FileHeader;
+	using ElfNativeSectionHeader = Elf32SectionHeader;
+	using ElfNativeSymbol = Elf32Symbol;
+	using ElfNativeRelocation = Elf32Relocation;
+	using ElfNativeRelocationA = Elf32RelocationA;
+	using ElfNativeProgramHeader = Elf32ProgramHeader;
+#elif ARCH(x86_64)
+	using ElfNativeAddr = Elf64Addr;
+	using ElfNativeOff = Elf64Off;
+	using ElfNativeHalf = Elf64Half;
+	using ElfNativeWord = Elf64Word;
+	using ElfNativeSword = Elf64Sword;
+	using ElfNativeXword = Elf64Xword;
+	using ElfNativeSxword = Elf64Sxword;
+	using ElfNativeFileHeader = Elf64FileHeader;
+	using ElfNativeSectionHeader = Elf64SectionHeader;
+	using ElfNativeSymbol = Elf64Symbol;
+	using ElfNativeRelocation = Elf64Relocation;
+	using ElfNativeRelocationA = Elf64RelocationA;
+	using ElfNativeProgramHeader = Elf64ProgramHeader;
+#endif
+
+}

LibELF/include/LibELF/Values.h

@@ -0,0 +1,140 @@
+#pragma once
+
+namespace LibELF
+{
+
+	enum ELF_Ident
+	{
+		ELFMAG0			= 0x7F,
+		ELFMAG1			= 'E',
+		ELFMAG2			= 'L',
+		ELFMAG3			= 'F',
+
+		ELFCLASSNONE	= 0,
+		ELFCLASS32		= 1,
+		ELFCLASS64		= 2,
+
+		ELFDATANONE		= 0,
+		ELFDATA2LSB		= 1,
+		ELFDATA2MSB		= 2,
+	};
+
+	enum ELF_EI
+	{
+		EI_MAG0			= 0,
+		EI_MAG1			= 1,
+		EI_MAG2			= 2,
+		EI_MAG3			= 3,
+		EI_CLASS		= 4,
+		EI_DATA			= 5,
+		EI_VERSION		= 6,
+		EI_OSABI		= 7,
+		EI_ABIVERSION	= 8,
+		EI_NIDENT		= 16,
+	};
+
+	enum ELF_ET
+	{
+		ET_NONE		= 0,
+		ET_REL		= 1,
+		ET_EXEC		= 2,
+		ET_DYN		= 3,
+		ET_CORE		= 4,
+		ET_LOOS		= 0xfe00,
+		ET_HIOS		= 0xfeff,
+		ET_LOPROC	= 0xff00,
+		ET_HIPROC	= 0xffff,
+	};
+
+	enum ELF_EV
+	{
+		EV_NONE		= 0,
+		EV_CURRENT	= 1,
+	};
+
+	enum ELF_SHT
+	{
+		SHT_NULL		= 0,
+		SHT_PROGBITS	= 1,
+		SHT_SYMTAB		= 2,
+		SHT_STRTAB		= 3,
+		SHT_RELA		= 4,
+		SHT_NOBITS		= 8,
+		SHT_REL			= 9,
+		SHT_SHLIB		= 10,
+		SHT_DYNSYM		= 11,
+		SHT_LOOS		= 0x60000000,
+		SHT_HIOS		= 0x6FFFFFFF,
+		SHT_LOPROC		= 0x70000000,
+		SHT_HIPROC		= 0x7FFFFFFF,
+	};
+
+	enum ELF_SHF
+	{
+		SHF_WRITE		= 0x1,
+		SHF_ALLOC		= 0x2,
+		SHF_EXECINSTR	= 0x4,
+		SHF_MASKOS		= 0x0F000000,
+		SHF_MASKPROC	= 0xF0000000,
+	};
+
+	enum ELF_SHN
+	{
+		SHN_UNDEF	= 0,
+		SHN_LOPROC	= 0xFF00,
+		SHN_HIPROC	= 0xFF1F,
+		SHN_LOOS	= 0xFF20,
+		SHN_HIOS	= 0xFF3F,
+		SHN_ABS		= 0xFFF1,
+		SHN_COMMON	= 0xFFF2,
+	};
+
+	enum ELF_STB
+	{
+		STB_LOCAL	= 0,
+		STB_GLOBAL	= 1,
+		STB_WEAK	= 2,
+		STB_LOOS	= 10,
+		STB_HIOS	= 12,
+		STB_LOPROC	= 13,
+		STB_HIPROC	= 15,
+	};
+
+	enum ELF_STT
+	{
+		STT_NOTYPE	= 0,
+		STT_OBJECT	= 1,
+		STT_FUNC	= 2,
+		STT_SECTION	= 3,
+		STT_FILE	= 4,
+		STT_LOOS	= 10,
+		STT_HIOS	= 12,
+		STT_LOPROC	= 13,
+		STT_HIPROC	= 15,
+	};
+
+	enum ELF_PT
+	{
+		PT_NULL		= 0,
+		PT_LOAD		= 1,
+		PT_DYNAMIC	= 2,
+		PT_INTERP	= 3,
+		PT_NOTE		= 4,
+		PT_SHLIB	= 5,
+		PT_PHDR		= 6,
+		PT_LOOS		= 0x60000000,
+		PT_HIOS		= 0x6FFFFFFF,
+		PT_LOPROC	= 0x70000000,
+		PT_HIPROC	= 0x7FFFFFFF,
+	};
+
+	enum ELF_PF
+	{
+		PF_X		= 0x1,
+		PF_W		= 0x2,
+		PF_R		= 0x4,
+		PF_MASKOS	= 0x00FF0000,
+		PF_MASKPROC	= 0xFF000000,
+	};
+
+}

README.md

@@ -0,0 +1,48 @@
+![license](https://img.shields.io/github/license/bananymous/banan-os)
+
+# banan-os
+
+This is my hobby operating system written in C++. Currently supports only x86\_64 architecture. We have a ext2 filesystem, basic ramfs, IDE disk drivers in ATA PIO mode, ATA AHCI drivers, userspace processes, executable loading from ELF format, linear VBE graphics and multithreaded processing on single core.
+
+![screenshot from qemu running banan-os](assets/banan-os.png)
+
+## Code structure
+
+Each major component and library has its own subdirectory (kernel, userspace, libc, ...). Each directory contains directory *include*, which has **all** of the header files of the component. Every header is included by its absolute path.
+
+## Building
+
+There does not exist a complete list of needed packages for building. From the top of my head I can say that *cmake*, *ninja*, *make*, *grub*, *rsync* and emulator (*qemu* or *bochs*) are needed.
+
+To build the toolchain for this os. You can run the following command.
+> ***NOTE:*** The following step has to be done only once. This might take a long time since we are compiling binutils and gcc.
+```sh
+./script/build.sh toolchain
+```
+
+To build the os itself you can run one of the following commands. You will need root access for disk image creation/modification.
+```sh
+./script/build.sh qemu
+./script/build.sh qemu-nographic
+./script/build.sh qemu-debug
+./script/build.sh bochs
+```
+
+You can also build the kernel or disk image without running it:
+```sh
+./script/build.sh kernel
+./script/build.sh image
+```
+
+If you have corrupted your disk image or want to create new one, you can either manually delete *build/banan-os.img* and build system will automatically create you a new one or you can run the following command.
+```sh
+./script/build.sh image-full
+```
+
+If you feel like ```./script/build.sh``` is too verbose, there exists a symlink _bos_ in this projects root directory. All build commands can be used with ```./bos args...``` instead.
+
+I have also created shell completion script for zsh. You can either copy the file in _script/shell-completion/zsh/\_bos_ to _/usr/share/zsh/site-functions/_ or add the _script/shell-completion/zsh_ to your fpath in _.zshrc_.
+
+### Contributing
+
+Currently I don't accept contributions to this repository unless explicitly told otherwise. This is a learning project for me and I want to do everything myself. Feel free to fork/clone this repo and tinker with it yourself.

bootloader/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.26)
+
+add_subdirectory(bios)

bootloader/bios/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(bootloader ASM)
+
+set(BOOTLOADER_SOURCES
+	boot.S
+	command_line.S
+	disk.S
+	elf.S
+	ext2.S
+	framebuffer.S
+	memory_map.S
+	utils.S
+)
+
+add_executable(bootloader ${BOOTLOADER_SOURCES})
+target_link_options(bootloader PRIVATE LINKER:-T,${CMAKE_CURRENT_SOURCE_DIR}/linker.ld)
+target_link_options(bootloader PRIVATE -nostdlib)

bootloader/bios/boot.S

@@ -0,0 +1,170 @@
+.code16
+
+#########################################
+#
+# STAGE 1 BOOTLOADER
+#
+# its sole purpose is to load stage2 from
+# bios boot partition
+#
+#########################################
+
+.section .stage1
+
+.global stage1_main
+stage1_main:
+	# setup segments
+	movw $0, %ax
+	movw %ax, %ds
+	movw %ax, %es
+
+	# setup stack
+	movw %ax, %ss
+	movl $0x7C00, %esp
+
+	# save boot disk number
+	call read_stage2_into_memory
+
+	jmp stage2_main
+
+.global print_and_halt
+print_and_halt:
+	call puts
+halt:
+	hlt
+	jmp halt
+
+
+#########################################
+#
+# STAGE 2 BOOTLOADER
+#
+#########################################
+
+.section .stage2
+
+stage2_main:
+	# clear screen and enter 80x25 text mode
+	movb $0x03, %al
+	movb $0x00, %ah
+	int $0x10
+
+	# print hello message
+	movw $hello_msg, %si
+	call puts; call print_newline
+
+	call enter_unreal_mode
+	movw $unreal_enter_msg, %si
+	call puts; call print_newline
+
+	call get_memory_map
+	call read_user_command_line
+	
+	call vesa_find_video_mode
+
+	call print_newline
+
+	movw $start_kernel_load_msg, %si
+	call puts; call print_newline
+
+	call print_memory_map
+
+	call find_root_disk
+	call find_root_partition
+
+	call print_root_partition_info
+	call print_newline
+
+	call has_ext2_filesystem
+	testb %al, %al
+	jz print_and_halt
+
+	call ext2_find_kernel
+	movl $ext2_inode_read_bytes, %esi
+
+	call elf_read_kernel_to_memory
+
+	call vesa_set_target_mode
+
+	cli
+
+	# setup protected mode
+	movl %cr0, %ebx
+	orb $1, %bl
+	movl %ebx, %cr0
+
+	# jump to kernel in protected mode
+	ljmpl $0x18, $protected_mode
+
+
+.code32
+protected_mode:
+	movw $0x10, %bx
+	movw %bx, %ds
+	movw %bx, %es
+	movw %bx, %fs
+	movw %bx, %gs
+	movw %bx, %ss
+
+	movl %eax, %ecx
+
+	movl $0xD3C60CFF, %eax
+	movl $banan_boot_info, %ebx
+	xorl %edx, %edx
+	xorl %esi, %esi
+	xorl %edi, %edi
+
+	jmp *%ecx
+
+
+.code16
+enter_unreal_mode:
+	cli
+	pushw %ds
+
+	lgdt gdtr
+
+	movl %cr0, %eax
+	orb $1, %al
+	movl %eax, %cr0
+	ljmpl $0x8, $.enter_unreal_mode_pmode
+
+ .enter_unreal_mode_pmode:
+	movw $0x10, %bx
+	movw %bx, %ds
+
+	andb 0xFE, %al
+	movl %eax, %cr0
+	ljmpl $0x0, $.enter_unreal_mode_unreal
+
+ .enter_unreal_mode_unreal:
+	popw %ds
+	sti
+
+	ret
+
+hello_msg:
+	.asciz "This is banan-os bootloader"
+
+unreal_enter_msg:
+	.asciz "Entered unreal mode"
+
+start_kernel_load_msg:
+	.asciz "Starting to load kernel"
+
+gdt:
+	.quad 0x0000000000000000
+	.quad 0x00009A000000FFFF
+	.quad 0x00CF92000000FFFF
+	.quad 0x00CF9A000000FFFF
+gdtr:
+	.short . - gdt - 1
+	.quad gdt
+
+banan_boot_info:
+	boot_command_line:
+		.long command_line
+	boot_framebuffer:
+		.long framebuffer
+	boot_memory_map:
+		.long memory_map

bootloader/bios/command_line.S

@@ -0,0 +1,83 @@
+.code16
+
+.section .stage2
+
+# fills command line buffer
+# NO REGISTERS SAVED
+.global read_user_command_line
+read_user_command_line:
+	# print initial command line
+	movw $command_line_enter_msg, %si
+	call puts
+	movw $command_line_buffer, %si
+	call puts
+
+	# prepare registers for input
+	movw $command_line_enter_msg, %si
+	movw $command_line_buffer, %di
+ .read_user_command_line_goto_end:
+	cmpb $0, (%di)
+	jz .read_user_command_line_loop
+	incw %di
+	jmp .read_user_command_line_goto_end
+
+ .read_user_command_line_loop:
+	call getc
+
+	cmpb $'\b', %al
+	je .read_user_command_line_backspace
+
+	# Not sure if some BIOSes return '\n' as enter, but check it just in case
+	cmpb $'\r', %al
+	je .read_user_command_line_done
+	cmpb $'\n', %al
+	je .read_user_command_line_done
+
+	pushw %ax
+
+	call isprint
+	testb %al, %al
+	jz .read_user_command_line_loop
+
+	popw %ax
+
+	# put byte to buffer
+	movb %al, (%di)
+	incw %di
+
+	# print byte
+	call putc
+
+	jmp .read_user_command_line_loop
+
+ .read_user_command_line_backspace:
+	# don't do anything if at the beginning
+	cmpw $command_line_buffer, %di
+	je .read_user_command_line_loop
+
+	# decrement buffer pointer
+	decw %di
+
+	# erase byte in display
+	call print_backspace
+
+	jmp .read_user_command_line_loop
+
+ .read_user_command_line_done:
+	# null terminate command line
+	movb $0, (%di)
+
+	call print_newline
+
+	ret
+
+
+command_line_enter_msg:
+	.asciz "cmdline: "
+
+.global command_line
+command_line:
+# 100 character command line
+command_line_buffer:
+	.ascii "root=/dev/sda2"
+	.skip 100 - 28

bootloader/bios/disk.S

@@ -0,0 +1,521 @@
+# FIXME: don't assume 512 byte sectors
+.set SECTOR_SIZE_SHIFT,	9
+.set SECTOR_SIZE,		1 << SECTOR_SIZE_SHIFT
+
+.code16
+
+.section .stage1
+
+.global stage2_start
+.global stage2_end
+
+# check that drive has int13 ext
+#	dl: drive number
+# returns only if drive does have the extension
+drive_has_int13_ext:
+	pusha
+
+	movb $0x41, %ah
+	movw $0x55AA, %bx
+	int $0x13
+	jc .drive_has_int13_ext_no_int13_ext
+
+	popa
+	ret
+
+ .drive_has_int13_ext_no_int13_ext:
+	mov $no_int13_ext_msg, %si
+	jmp print_and_halt
+
+
+# read sectors from disk
+# bx:eax:	lba start
+# cx:		lba count (has to less than 0x80)
+# dl:		drive number
+# ds:di:	physical address
+# returns only on success
+.global read_from_disk
+read_from_disk:
+	pusha
+
+	call drive_has_int13_ext
+
+	# prepare disk read packet
+	mov $disk_address_packet, %si
+	movb $0x10,	0x00(%si)	# packet size
+	movb $0x00,	0x01(%si)	# always 0
+	movw %cx,	0x02(%si)	# lba count
+	movw %di,	0x04(%si)	# offset
+	movw %ds,	0x06(%si)	# segment
+	movl %eax,	0x08(%si)	# 32 bit lower lba
+	movw %bx,	0x0C(%si)	# 16 bit upper lba
+	movw $0,	0x0E(%si)	# zero
+
+	# issue read command
+	mov $0x42, %ah
+	int $0x13
+	jc .read_from_disk_failed
+
+	popa
+	ret
+
+ .read_from_disk_failed:
+	mov $read_from_disk_msg, %si
+	jmp print_and_halt
+
+
+# Reads GPT header into gpt_header buffer
+#	dl: drive number
+# return:
+#	ax: 1 if has GPT header, 0 otherwise
+.global read_gpt_header
+read_gpt_header:
+	pushw %bx
+	pushw %cx
+	pushw %di
+
+	xorw %bx, %bx
+	movl $1, %eax
+	movw $1, %cx
+	movw $gpt_header, %di
+	call read_from_disk
+
+	xorw %bx, %bx
+	movw $1, %ax
+
+	# check if header starts with 'EFI PART'
+	cmpl $0x20494645, (gpt_header + 0)
+	cmovnew %bx, %ax
+	cmpl $0x54524150, (gpt_header + 4)
+	cmovnew %bx, %ax
+
+	popw %di
+	popw %cx
+	popw %bx
+	ret
+
+
+# Find bios boot partition from boot drive
+# returns:
+#	bx:eax:	first lba
+#	cx:		sector count
+find_stage2_partition:
+	# read boot disk GPT header
+	movb (boot_disk_number), %dl
+	call read_gpt_header
+
+	testb %al, %al
+	jz .find_stage2_partition_not_gpt
+
+	# eax := entry_count
+	movl (gpt_header + 80), %eax
+	test %eax, %eax
+	jz .find_stage2_partition_not_found
+
+	# edx:eax := eax * entry_size
+	mull (gpt_header + 84)
+	test %edx, %edx
+	jnz .find_stage2_partition_too_big_entries
+
+	# FIXME: read one entry array section at a time
+
+	# sector count := (arr_size + SECTOR_SIZE - 1) / SECTOR_SIZE
+	movl %eax, %ecx
+	shrl $SECTOR_SIZE_SHIFT, %ecx
+
+	# start lba
+	movl (gpt_header + 72), %eax
+	movw (gpt_header + 76), %bx
+
+	movw $gpt_entry_data, %di
+	movw $bios_boot_guid, %si
+	movb (boot_disk_number), %dl
+
+	call read_from_disk
+
+	# NOTE: 'only' 0xFFFF partitions supported,
+	#       although read will fail with more than 0x80
+	movw (gpt_header + 80), %cx
+
+ .find_stage2_partition_loop_gpt_entries:
+	pushw %cx
+	movw $16, %cx
+	call memcmp
+	popw %cx
+
+	testb %al, %al
+	jnz .find_stage2_partition_found
+
+	# add entry size to entry pointer
+	addw (gpt_header + 84), %di
+
+	loop .find_stage2_partition_loop_gpt_entries
+
+	# fall through to not found case
+ .find_stage2_partition_not_found:
+	movw $no_bios_boot_partition_msg, %si
+	jmp print_and_halt
+
+ .find_stage2_partition_not_gpt:
+	movw $not_gpt_partition_msg, %si
+	jmp print_and_halt
+
+ .find_stage2_partition_too_big_entries:
+	movw $too_gpt_big_entries_msg, %si
+	jmp print_and_halt
+
+ .find_stage2_partition_found:
+	# first lba
+	movl 32(%di), %eax
+	movw 36(%di), %bx
+
+	# count := last lba - first lba + 1
+	movl 40(%di), %ecx
+	subl %eax, %ecx
+	incl %ecx
+
+	ret
+
+# reads stage2 into memory
+#	dl: boot drive number
+# returns only on success
+.global read_stage2_into_memory
+read_stage2_into_memory:
+	movb %dl, (boot_disk_number)
+
+	# push stage2 sector count
+	movl $stage2_end, %eax
+	subl $stage2_start, %eax
+	addl $(SECTOR_SIZE - 1), %eax
+	movl $SECTOR_SIZE, %ecx
+	xorl %edx, %edx
+	divl %ecx
+	pushl %eax
+
+	call find_stage2_partition
+
+	movb (boot_disk_number), %dl
+	popl %ecx # FIXME: validate that partition has enough sectors
+	movw $stage2_start, %di
+	call read_from_disk
+
+	ret
+
+# 21686148-6449-6E6F-744E-656564454649
+.align 4
+bios_boot_guid:
+	.long 0x21686148		# little endian
+	.word 0x6449			# little endian
+	.word 0x6E6F			# little endian
+	.word 0x4E74			# big endian
+	.quad 0x494645646565	# big endian
+
+boot_disk_number:
+	.skip 1
+
+read_from_disk_msg:
+	.asciz "read error"
+
+no_int13_ext_msg:
+	.asciz "no INT13 ext"
+
+no_bios_boot_partition_msg:
+	.asciz "no bios boot"
+
+too_gpt_big_entries_msg:
+	.asciz "too big GPT array"
+
+not_gpt_partition_msg:
+	.asciz "not GPT"
+
+
+.section .stage2
+
+# check if drive exists
+#	dl: drive number
+# return:
+#	al: 1 if disk is usable, 0 otherwise
+drive_exists:
+	pusha
+
+	movb $0x48, %ah
+	movw $disk_drive_parameters, %si
+	movw $0x1A, (disk_drive_parameters) # set buffer size
+
+	int $0x13
+	jc .drive_exists_nope
+
+	popa
+	movb $1, %al
+	ret
+
+ .drive_exists_nope:
+	popa
+	movb $0, %al
+	ret
+
+# find root disk and populate root_disk_drive_number field
+# NO REGISTERS SAVED
+.global find_root_disk
+find_root_disk:
+	movb $0x80, %dl
+
+ .find_root_disk_loop:
+	call drive_exists
+	testb %al, %al
+	jz .find_root_disk_not_found
+
+	# read GPT header
+	xorw %bx, %bx
+	movl $1, %eax
+	movw $1, %cx
+	movw $gpt_header, %di
+	call read_from_disk
+
+	# confirm header (starts with 'EFI PART')
+	cmpl $0x20494645, (gpt_header + 0)
+	jne .find_root_disk_next_disk
+	cmpl $0x54524150, (gpt_header + 4)
+	jne .find_root_disk_next_disk
+
+	# compare disk GUID
+	movw $root_disk_guid, %si
+	movw $(gpt_header + 56), %di
+	movw $16, %cx
+	call memcmp
+	testb %al, %al
+	jz .find_root_disk_next_disk
+
+	movw $root_disk_found_msg, %si
+	call puts; call print_newline
+
+	movb %dl, (root_disk_drive_number)
+	ret
+
+ .find_root_disk_next_disk:
+	incb %dl
+	jmp .find_root_disk_loop
+
+ .find_root_disk_not_found:
+	movw $root_disk_not_found_msg, %si
+	jmp print_and_halt
+
+
+# finds root partition from root disk
+# fills root_partition_entry data structure
+# NOTE: assumes GPT header is in `gpt_header`
+# NO REGISTERS SAVED
+# return:
+#	dl:		drive number
+#	ecx:	sector count (capped at 0xFFFFFFFF)
+#	bx:eax:	first sector
+.global find_root_partition
+find_root_partition:
+	pushl %ebp
+	movl %esp, %ebp
+	subl $16, %esp
+
+	# esp + 0: 8 byte entry array lba
+	movl (gpt_header + 72), %eax
+	movl %eax, 0(%esp)
+	movl (gpt_header + 76), %eax
+	movl %eax, 4(%esp)
+	# FIXME: check that bits 48-63 are zero
+
+	# esp + 8: 4 byte entries per sector
+	xorl %edx, %edx
+	movl $SECTOR_SIZE, %eax
+	divl (gpt_header + 84)
+	movl %eax, 8(%esp)
+
+	# esp + 12: 4 byte entries remaining
+	movl (gpt_header + 80), %eax
+	testl %eax, %eax
+	jz .find_root_partition_not_found
+	movl %eax, 12(%esp)
+
+ .find_root_partition_read_entry_section:
+	movl 0(%esp), %eax
+	movl 4(%esp), %ebx
+	movw $1, %cx
+	movb (root_disk_drive_number), %dl
+	movw $sector_buffer, %di
+	call read_from_disk
+
+	# ecx: min(entries per section, entries remaining)
+	movl 8(%esp), %ecx
+	cmpl 12(%esp), %ecx
+	jae .find_root_partition_got_entry_count
+	movl 12(%esp), %ecx
+
+ .find_root_partition_got_entry_count:
+	# update entries remaining
+	subl %ecx, 12(%esp)
+
+	# si: entry pointer
+	movw $sector_buffer, %si
+
+ .find_root_partition_loop_entries:
+	# temporarily save cx in dx
+	movw %cx, %dx
+
+	# check that entry is used
+	movw $16, %cx
+	movw $zero_guid, %di
+	call memcmp
+	test %al, %al
+	jnz .find_root_partition_next_entry
+
+	# compare entry guid to root guid
+	movw $16, %cx
+	addw $16, %si
+	movw $root_partition_guid, %di
+	call memcmp
+	subw $16, %si
+
+	testb %al, %al
+	jnz .find_root_partition_found
+
+ .find_root_partition_next_entry:
+
+	# restore cx
+	movw %dx, %cx
+
+	# entry pointer += entry size
+	addw (gpt_header + 84), %si
+	loop .find_root_partition_loop_entries
+
+	# entry not found in this sector
+
+	# increment 8 byte entry array lba
+	incl 0(%esp)
+	jnc .find_root_partition_no_overflow
+	incl 4(%esp)
+
+ .find_root_partition_no_overflow:
+	# loop to read next section if entries remaining
+	cmpl $0, 12(%esp)
+	jnz .find_root_partition_read_entry_section
+
+ .find_root_partition_not_found:
+	movw $root_partition_not_found_msg, %si
+	jmp print_and_halt
+
+ .find_root_partition_found:
+	# copy entry to buffer
+	movw $root_partition_entry, %di
+	movw $128, %cx
+	rep movsb
+
+	movw $root_partition_found_msg, %si
+	call puts; call print_newline
+
+	# ebx:eax := last lba
+	movl (root_partition_entry + 44), %ebx
+	movl (root_partition_entry + 40), %eax
+
+	# ebx:eax -= first lba - 1
+	subl (root_partition_entry + 36), %ebx
+	movl (root_partition_entry + 32), %ecx;
+	decl %ecx
+	subl %ecx, %eax
+	jnc .find_root_partition_count_sub_no_carry
+	decl %ebx
+ .find_root_partition_count_sub_no_carry:
+ 	
+	# ecx: min(partition count, 0xFFFFFFFF)
+	movl $0xFFFFFFFF, %edx
+	movl %eax, %ecx
+	testl %ebx, %ebx
+	cmovnzl %edx, %ecx
+
+	# ebx:eax := first lba
+	# FIXME: confirm ebx bits 16:31 are zero
+	movl (root_partition_entry + 36), %ebx
+	movl (root_partition_entry + 32), %eax
+
+	movb (root_disk_drive_number), %dl
+
+	leavel
+	ret
+
+
+# print information about root partition
+.global print_root_partition_info
+print_root_partition_info:
+	pushw %ax
+	pushw %bx
+	pushw %cx
+	pushw %si
+
+	movw $root_partition_info_start_msg, %si
+	call puts;
+
+	movw $16, %bx
+	movw $2,  %cx
+	movw (root_partition_entry + 38), %ax; call print_number
+	movw (root_partition_entry + 36), %ax; call print_number
+	movw (root_partition_entry + 34), %ax; call print_number
+	movw (root_partition_entry + 32), %ax; call print_number
+
+	movb $'-', %al; call putc
+	movb $'>', %al; call putc
+
+	movw (root_partition_entry + 46), %ax; call print_number
+	movw (root_partition_entry + 44), %ax; call print_number
+	movw (root_partition_entry + 42), %ax; call print_number
+	movw (root_partition_entry + 40), %ax; call print_number
+
+	call print_newline
+
+	popw %si
+	popw %cx
+	popw %bx
+	popw %ax
+	ret
+
+
+# These will be patched during bootloader installation
+root_disk_guid:
+	.ascii "root disk guid  "
+root_partition_guid:
+	.ascii "root part guid  "
+zero_guid:
+	.skip 16, 0
+
+root_disk_found_msg:
+	.asciz "Root disk found!"
+root_disk_not_found_msg:
+	.asciz "Root disk not found"
+
+root_partition_found_msg:
+	.asciz "Root partition found!"
+root_partition_not_found_msg:
+	.asciz "Root partition not found"
+
+root_partition_info_start_msg:
+	.asciz "Root partition: "
+
+.section .bss
+
+.align SECTOR_SIZE
+gpt_header:
+	.skip SECTOR_SIZE
+gpt_entry_data:
+	.skip SECTOR_SIZE
+sector_buffer:
+	.skip SECTOR_SIZE
+
+disk_address_packet:
+	.skip 16
+
+disk_drive_parameters:
+	.skip 0x1A
+	.skip 2 # padding
+
+root_disk_drive_number:
+	.skip 1
+	.skip 3 # padding
+
+root_partition_entry:
+	.skip 128

bootloader/bios/elf.S

@@ -0,0 +1,222 @@
+.set SECTOR_SIZE,	512
+
+# file header field offsets
+.set e_type,		16
+.set e_machine,		18
+.set e_version,		20
+.set e_entry,		24
+.set e_phoff,		32
+.set e_shoff,		40
+.set e_flags,		48
+.set e_ehsize,		52
+.set e_phentsize,	54
+.set e_phnum,		56
+.set e_shentsize,	58
+.set e_shnum,		60
+.set e_shstrndx,	62
+
+# e_ident offsets
+.set EI_CLASS,		4
+.set EI_DATA,		5
+.set EI_VERSION,	6
+
+# e_ident constants
+.set ELFMAGIC,		0x464C457F
+.set ELFCLASS64,	2
+.set ELFDATA2LSB,	1
+.set EV_CURRENT,	1
+
+# e_type constants
+.set ET_EXEC,		2
+
+# program header field offsets
+.set p_type,		0
+.set p_flags,		4
+.set p_offset,		8
+.set p_vaddr,		16
+.set p_paddr,		24
+.set p_filesz,		32
+.set p_memsz,		40
+.set p_align,		48
+
+# p_type constants
+.set PT_NULL,		0
+.set PT_LOAD,		1
+
+.code16
+.section .stage2
+
+# Validate file header stored in elf_file_header
+# returns only on success
+elf_validate_file_header:
+	cmpl $ELFMAGIC, (elf_file_header)
+	jne .elf_validate_file_header_invalid_magic
+
+	cmpb $ELFCLASS64, (elf_file_header + EI_CLASS)
+	jne .elf_validate_file_header_only_64bit_supported
+
+	cmpb $ELFDATA2LSB, (elf_file_header + EI_DATA)
+	jne .elf_validate_file_header_only_little_endian_supported
+
+	cmpb $EV_CURRENT, (elf_file_header + EI_VERSION)
+	jne .elf_validate_file_header_not_current_version
+
+	cmpl $EV_CURRENT, (elf_file_header + e_version)
+	jne .elf_validate_file_header_not_current_version
+
+	cmpw $ET_EXEC, (elf_file_header + e_type)
+	jne .elf_validate_file_header_not_executable
+
+	ret
+
+ .elf_validate_file_header_invalid_magic:
+	movw $elf_validate_file_header_invalid_magic_msg, %si
+	jmp print_and_halt
+ .elf_validate_file_header_only_64bit_supported:
+	movw $elf_validate_file_header_only_64bit_supported_msg, %si
+	jmp print_and_halt
+ .elf_validate_file_header_only_little_endian_supported:
+	movw $elf_validate_file_header_only_little_endian_supported_msg, %si
+	jmp print_and_halt
+ .elf_validate_file_header_not_current_version:
+	movw $elf_validate_file_header_not_current_version_msg, %si
+	jmp print_and_halt
+ .elf_validate_file_header_not_executable:
+	movw $elf_validate_file_header_not_executable_msg, %si
+	jmp print_and_halt
+
+
+# read callback format
+#	eax: first byte
+#	ecx: byte count
+#	edi: buffer
+# returns only on success
+
+
+# reads kernel to memory
+#	esi:	callback for reading from kernel image
+# return:
+#	eax:	kernel entry address
+.global elf_read_kernel_to_memory
+elf_read_kernel_to_memory:
+	pushal
+	pushl %ebp
+	movl %esp, %ebp
+	subl $2, %esp
+
+	# read file header
+	movl $0, %eax
+	movl $64, %ecx
+	movl $elf_file_header, %edi
+	call *%esi
+
+	call elf_validate_file_header
+
+	cmpl $0, (elf_file_header + e_phoff + 4)
+	jnz .elf_read_kernel_to_memory_unsupported_offset
+
+	# current program header
+	movw $0, -2(%ebp)
+
+ .elf_read_kernel_to_memory_loop_program_headers:
+	movw -2(%ebp), %cx
+	cmpw (elf_file_header + e_phnum), %cx
+	jae .elf_read_kernel_to_memory_done
+
+	# eax := program_header_index * e_phentsize + e_phoff
+	xorl %eax, %eax
+	movw %cx, %ax
+	xorl %ebx, %ebx
+	movw (elf_file_header + e_phentsize), %bx
+	mull %ebx
+	addl (elf_file_header + e_phoff), %eax
+	jc .elf_read_kernel_to_memory_unsupported_offset
+
+	# setup program header size and address
+	movl $56, %ecx
+	movl $elf_program_header, %edi
+
+	# read the program header
+	call *%esi
+
+	# test if program header is empty
+	cmpl $PT_NULL, (elf_program_header + p_type)
+	je .elf_read_kernel_to_memory_null_program_header
+
+	# confirm that the program header is loadable
+	cmpl $PT_LOAD, (elf_program_header + p_type)
+	jne .elf_read_kernel_to_memory_not_loadable_header
+
+	# memset p_filesz -> p_memsz to 0
+	movl (elf_program_header + p_filesz), %ebx
+
+	movl (elf_program_header + p_vaddr),  %edi
+	andl $0x7FFFFFFF, %edi
+	addl %ebx, %edi
+
+	movl (elf_program_header + p_memsz),  %ecx
+	subl %ebx, %ecx
+	jz .elf_read_kernel_to_memory_memset_done
+
+ .elf_read_kernel_to_memory_memset:
+	movb $0, (%edi)
+	incl %edi
+	decl %ecx
+	jnz .elf_read_kernel_to_memory_memset
+ .elf_read_kernel_to_memory_memset_done:
+
+	# read file specified in program header to memory
+	movl (elf_program_header + p_offset), %eax
+	movl (elf_program_header + p_vaddr),  %edi
+	andl $0x7FFFFFFF, %edi
+	movl (elf_program_header + p_filesz), %ecx
+
+	#call print_hex32; call print_newline
+
+	call *%esi
+
+ .elf_read_kernel_to_memory_null_program_header:
+	incw -2(%ebp)
+	jmp .elf_read_kernel_to_memory_loop_program_headers
+
+ .elf_read_kernel_to_memory_done:
+	leavel
+	popal
+
+	# set kernel entry address
+	movl (elf_file_header + e_entry), %eax
+	andl $0x7FFFFF, %eax
+
+	ret
+
+ .elf_read_kernel_to_memory_unsupported_offset:
+	movw $elf_read_kernel_to_memory_unsupported_offset_msg, %si
+	jmp print_and_halt
+ .elf_read_kernel_to_memory_not_loadable_header:
+	movw $elf_read_kernel_to_memory_not_loadable_header_msg, %si
+	jmp print_and_halt
+
+
+elf_validate_file_header_invalid_magic_msg:
+	.asciz "ELF: file has invalid ELF magic"
+elf_validate_file_header_only_64bit_supported_msg:
+	.asciz "ELF: file is not targettint 64 bit"
+elf_validate_file_header_only_little_endian_supported_msg:
+	.asciz "ELF: file is not in little endian format"
+elf_validate_file_header_not_current_version_msg:
+	.asciz "ELF: file is not in current ELF version"
+elf_validate_file_header_not_executable_msg:
+	.asciz "ELF: file is not an executable"
+
+elf_read_kernel_to_memory_unsupported_offset_msg:
+	.asciz "ELF: unsupported offset (only 32 bit offsets supported)"
+elf_read_kernel_to_memory_not_loadable_header_msg:
+	.asciz "ELF: kernel contains non-loadable program header"
+
+.section .bss
+
+elf_file_header:
+	.skip 64
+
+elf_program_header:
+	.skip 56

bootloader/bios/ext2.S

@@ -0,0 +1,705 @@
+# FIXME: don't assume 512 byte sectors
+.set SECTOR_SHIFT,	9
+.set SECTOR_SIZE,	1 << SECTOR_SHIFT
+
+# FIXME: don't assume 1024 byte blocks
+.set EXT2_BLOCK_SHIFT,		10
+.set EXT2_BLOCK_SIZE,		1 << EXT2_BLOCK_SHIFT
+.set EXT2_SUPERBLOCK_SIZE,	264
+.set EXT2_BGD_SHIFT,		5
+.set EXT2_BGD_SIZE,			1 << EXT2_BGD_SHIFT
+.set EXT2_INODE_SIZE_MAX,	256
+.set EXT2_ROOT_INO,			2
+.set EXT2_GOOD_OLD_REV,		0
+
+# inode types
+.set EXT2_S_IMASK,			0xF000
+.set EXT2_S_IFDIR,			0x4000
+.set EXT2_S_IFREG,			0x8000
+
+# superblock offsets
+.set s_log_block_size,		24
+.set s_inodes_per_group,	40
+.set s_magic,				56
+.set s_rev_level,			76
+.set s_inode_size,			88
+
+# block group descriptor offsets
+.set bg_inode_table,		8
+
+# inode offsets
+.set i_mode,				0
+.set i_size,				4
+.set i_block,				40
+
+
+.code16
+.section .stage2
+
+# checks whether partition contains ext2 filesystem.
+# fills ext2_superblock_buffer
+#	dl:		drive number
+#	ecx:	sector count
+#	bx:eax:	first sector
+# return:
+#	al: 1 if is ext2, 0 otherwise
+#	si: error message on error
+.global has_ext2_filesystem
+has_ext2_filesystem:
+	pushl %ecx
+	pushw %bx
+	pushw %di
+
+	# fill ext2_partition_first_sector
+	movw $0,   (ext2_partition_first_sector + 6)
+	movw %bx,  (ext2_partition_first_sector + 4)
+	movl %eax, (ext2_partition_first_sector + 0)
+
+	# fill ext2_drive_number
+	movb %dl, (ext2_drive_number)
+
+	cmpl $3, %ecx
+	jb .has_ext2_filesystem_does_not_fit
+
+	# one sector
+	movw $1, %cx
+
+	# from byte offset 1024
+	addl $(1024 / SECTOR_SIZE), %eax
+	jnc .has_ext2_filesystem_no_overflow
+	incw %bx
+ .has_ext2_filesystem_no_overflow:
+
+	# into sector buffer
+	movw $ext2_block_buffer, %di
+
+	call read_from_disk
+
+	# copy superblock to its buffer
+	movw $ext2_block_buffer, %si
+	movw $ext2_superblock_buffer, %di
+	movw $EXT2_SUPERBLOCK_SIZE, %cx
+	rep movsb
+
+	# verify magic
+	cmpw $0xEF53, (ext2_superblock_buffer + s_magic)
+	jne .has_ext2_filesystem_invalid_magic
+
+	# verify block size
+	  # verify shift fits in one byte
+	movl (ext2_superblock_buffer + s_log_block_size), %ecx
+	testl $0xFFFFFF00, %ecx
+	jnz .has_ext2_filesystem_unsupported_block_size
+	  # verify 1024 << s_log_block_size == EXT2_BLOCK_SIZE
+	movl $1024, %eax
+	shll %cl, %eax
+	cmpl $EXT2_BLOCK_SIZE, %eax
+	jne .has_ext2_filesystem_unsupported_block_size
+
+	# fill inode size
+	movl $128, %eax
+	cmpl $EXT2_GOOD_OLD_REV, (ext2_superblock_buffer + s_rev_level)
+	cmovnel (ext2_superblock_buffer + s_inode_size), %eax
+	movl %eax, (ext2_inode_size)
+
+	movb $1, %al
+	jmp .has_ext2_filesystem_done
+
+ .has_ext2_filesystem_does_not_fit:
+	movw $root_partition_does_not_fit_ext2_filesystem_msg, %si
+	movb $0, %al
+	jmp .has_ext2_filesystem_done
+
+ .has_ext2_filesystem_invalid_magic:
+	movw $root_partition_has_invalid_ext2_magic_msg, %si
+	movb $0, %al
+	jmp .has_ext2_filesystem_done
+
+ .has_ext2_filesystem_unsupported_block_size:
+	movw $root_partition_has_unsupported_ext2_block_size_msg, %si
+	movb $0, %al
+	jmp .has_ext2_filesystem_done
+
+ .has_ext2_filesystem_done:
+	popw %di
+	popw %bx
+	popl %ecx
+	ret
+
+
+# reads block in to ext2_block_buffer
+#	eax:	block number
+ext2_read_block:
+	pushl %eax
+	pushl %ebx
+	pushw %cx
+	pushl %edx
+	pushw %di
+
+	# NOTE: this assumes 1024 block size
+	# eax := (block * block_size) / sector_size := (eax << EXT2_BLOCK_SHIFT) >> SECTOR_SHIFT
+	xorl %edx, %edx
+	shll $EXT2_BLOCK_SHIFT, %eax
+	shrl $SECTOR_SHIFT, %eax
+
+	# ebx:eax := eax + (ext2_partition_first_sector)
+	movl (ext2_partition_first_sector + 4), %ebx
+	addl (ext2_partition_first_sector + 0), %eax
+	jnc .ext2_read_block_no_carry
+	incl %ebx
+ .ext2_read_block_no_carry:
+
+	# sectors per block
+	movw $(EXT2_BLOCK_SIZE / SECTOR_SIZE), %cx
+
+	movw $ext2_block_buffer, %di
+
+	movb (ext2_drive_number), %dl
+	call read_from_disk
+
+	popw %di
+	popl %edx
+	popw %cx
+	popl %ebx
+	popl %eax
+	ret
+
+
+# reads block group descrtiptor into ext2_block_group_descriptor
+#	eax:	block group
+ext2_read_block_group_descriptor:
+	pushal
+
+	# eax := bgd_byte_offset := 2048 + EXT2_BGD_SIZE * eax := (eax << EXT2_BGD_SHIFT) + 2048
+	shll $EXT2_BGD_SHIFT, %eax
+	addl $2048, %eax
+
+	# eax: bgd_block  := bgd_byte_offset / EXT2_BLOCK_SIZE
+	# ebx: bgd_offset := bgd_byte_offset % EXT2_BLOCK_SIZE
+	xorl %edx, %edx
+	movl $EXT2_BLOCK_SIZE, %ebx
+	divl %ebx
+	movl %edx, %ebx
+
+	call ext2_read_block
+
+	# esi := &ext2_block_buffer + bgd_offset := ebx + &ext2_block_buffer
+	# edi := &ext2_block_group_descriptor_buffer
+	movl %ebx, %esi
+	addl $ext2_block_buffer, %esi
+	movl $ext2_block_group_descriptor_buffer, %edi
+	movw $EXT2_BGD_SIZE, %cx
+	rep movsb
+
+	popal
+	ret
+
+
+# reads inode into ext2_inode_buffer
+#	eax:	ino
+ext2_read_inode:
+	pushal
+
+	# eax := block_group = (ino - 1) / s_inodes_per_group
+	# ebx := inode_index = (ino - 1) % s_inodes_per_group
+	xorl %edx, %edx
+	decl %eax
+	movl (ext2_superblock_buffer + s_inodes_per_group), %ebx
+	divl %ebx
+	movl %edx, %ebx
+
+	call ext2_read_block_group_descriptor
+
+	# eax := inode_table_block  := (inode_index * inode_size) / EXT2_BLOCK_SIZE
+	# ebx := inode_table_offset := (inode_index * inode_size) % EXT2_BLOCK_SIZE
+	xorl %edx, %edx
+	movl %ebx, %eax
+	movl (ext2_inode_size), %ebx
+	mull %ebx
+	movl $EXT2_BLOCK_SIZE, %ebx
+	divl %ebx
+	movl %edx, %ebx
+
+	# eax := file system block := eax + bg_inode_table
+	addl (ext2_block_group_descriptor_buffer + bg_inode_table), %eax
+
+	movb (ext2_drive_number), %dl
+	call ext2_read_block
+
+	# copy inode memory
+	  # esi := inode_table_offset + ext2_block_buffer := edx + ext2_block_buffer
+	movl %ebx, %esi
+	addl $ext2_block_buffer, %esi
+	  # edi := ext2_inode_buffer
+	movl $ext2_inode_buffer, %edi
+	  # ecx := inode_size
+	movl (ext2_inode_size), %ecx
+	rep movsb
+
+	popal
+	ret
+
+
+# gets block index from n'th data block in inode stored in ext2_inode_buffer
+#	eax:	data block index
+# return:
+#	eax:	block index
+ext2_data_block_index:
+	pushl %ebx
+	pushl %ecx
+	pushl %edx
+	pushl %esi
+
+	# calculate max data blocks
+	movl (ext2_inode_buffer + i_size), %ecx
+	addl (ext2_inode_size), %ecx
+	decl %ecx
+	shll $EXT2_BLOCK_SHIFT, %ecx
+
+	# verify data block is within bounds
+	cmpl %ecx, %eax
+	jae .ext2_data_block_index_out_of_bounds
+
+	# check if this is direct block access
+	cmpl $12, %eax
+	jb .ext2_data_block_index_direct
+	subl $12, %eax
+
+	# check if this is singly indirect block access
+	cmpl $(EXT2_BLOCK_SIZE / 4), %eax
+	jb .ext2_data_block_index_singly_indirect
+	subl $(EXT2_BLOCK_SIZE / 4), %eax
+
+	# check if this is doubly indirect block access
+	cmpl $((EXT2_BLOCK_SIZE / 4) * (EXT2_BLOCK_SIZE / 4)), %eax
+	jb .ext2_data_block_index_doubly_indirect
+	subl $((EXT2_BLOCK_SIZE / 4) * (EXT2_BLOCK_SIZE / 4)), %eax
+
+	# check if this is triply indirect block access
+	cmpl $((EXT2_BLOCK_SIZE / 4) * (EXT2_BLOCK_SIZE / 4) * (EXT2_BLOCK_SIZE / 4)), %eax
+	jb .ext2_data_block_index_triply_indirect
+
+	# otherwise this is invalid access
+	jmp .ext2_data_block_index_invalid
+
+ .ext2_data_block_index_direct:
+	movl $(ext2_inode_buffer + i_block), %esi
+	movl (%esi, %eax, 4), %eax
+	jmp .ext2_data_block_index_done
+
+ .ext2_data_block_index_singly_indirect:
+	movl %eax, %ebx
+	movl (ext2_inode_buffer + i_block + 12 * 4), %eax
+	movw $1, %cx
+	jmp .ext2_data_block_index_indirect
+
+ .ext2_data_block_index_doubly_indirect:
+	movl %eax, %ebx
+	movl (ext2_inode_buffer + i_block + 13 * 4), %eax
+	movw $2, %cx
+	jmp .ext2_data_block_index_indirect
+
+ .ext2_data_block_index_triply_indirect:
+	movl %eax, %ebx
+	movl (ext2_inode_buffer + i_block + 14 * 4), %eax
+	movw $3, %cx
+	jmp .ext2_data_block_index_indirect
+
+	# eax := current block
+	# ebx := index
+	# cx  := depth
+ .ext2_data_block_index_indirect:
+	call ext2_read_block
+
+	# store depth and index
+	pushw %cx
+	pushl %ebx
+
+	cmpw $1, %cx
+	jbe .ext2_data_block_index_no_shift
+
+	# cl := shift
+	movb $(EXT2_BLOCK_SHIFT - 2), %al
+	decb %cl
+	mulb %cl
+	movb %al, %cl
+
+	# ebx := ebx >> cl
+	shrl %cl, %ebx
+
+ .ext2_data_block_index_no_shift:
+	# edx := index of next block
+	movl %ebx, %eax
+	xorl %edx, %edx
+	movl $(EXT2_BLOCK_SIZE / 4), %ebx
+	divl %ebx
+
+	# eax := next block
+	movl $ext2_block_buffer, %esi
+	movl (%esi, %edx, 4), %eax
+
+	# restore depth and index
+	popl %ebx
+	popw %cx
+
+	loop .ext2_data_block_index_indirect
+
+	jmp .ext2_data_block_index_done
+
+ .ext2_data_block_index_out_of_bounds:
+	movw $ext2_data_block_index_out_of_bounds_msg, %si
+	call puts; call print_newline
+	movl $0, %eax
+	jmp .ext2_data_block_index_done
+
+ .ext2_data_block_index_invalid:
+	movw $ext2_data_block_index_invalid_msg, %si
+	call puts; call print_newline
+	movl $0, %eax
+	jmp .ext2_data_block_index_done
+
+ .ext2_data_block_index_done:
+	popl %esi
+	popl %edx
+	popl %ecx
+	popl %ebx
+	ret
+
+
+# read bytes from inode (implements read callback)
+#	eax: first byte
+#	ecx: byte count
+#	edi: buffer
+# returns only on success
+.global ext2_inode_read_bytes
+ext2_inode_read_bytes:
+	pushal
+	pushl %ebp
+	movl %esp, %ebp
+	subl $8, %esp
+
+	# save read info
+	movl %eax, 0(%esp)
+	movl %ecx, 4(%esp)
+
+	# check if eax % EXT2_BLOCK_SIZE != 0,
+	# then we need to read a partial block starting from an offset
+	xorl %edx, %edx
+	movl $EXT2_BLOCK_SIZE, %ebx
+	divl %ebx
+	testl %edx, %edx
+	jz .ext2_inode_read_bytes_no_partial_start
+
+	# get data block index and read block
+	call ext2_data_block_index
+	call ext2_read_block
+
+	# ecx := byte count (min(block_size - edx, remaining_bytes))
+	movl $EXT2_BLOCK_SIZE, %ecx
+	subl %edx, %ecx
+	cmpl %ecx, 4(%esp)
+	cmovbl 4(%esp), %ecx
+
+	# update remaining read info
+	addl %ecx, 0(%esp)
+	subl %ecx, 4(%esp)
+
+	# esi := start sector data (block_buffer + index * SECTOR_SIZE)
+	movl $ext2_block_buffer, %esi
+	addl %edx, %esi
+
+	# very dumb memcpy with 32 bit addresses
+	movl $0, %ebx
+ .ext2_inode_read_bytes_memcpy_partial:
+	movb (%esi, %ebx), %al
+	movb %al, (%edi, %ebx)
+	incl %ebx
+	decl %ecx
+	jnz .ext2_inode_read_bytes_memcpy_partial
+	addl %ebx, %edi
+
+	# check if all sectors are read
+	cmpl $0, 4(%esp)
+	je .ext2_inode_read_bytes_done
+
+ .ext2_inode_read_bytes_no_partial_start:
+	# eax := data block index (byte_start / block_size)
+	movl 0(%esp), %eax
+	shrl $(EXT2_BLOCK_SHIFT), %eax
+
+	# get data block index and read block
+	call ext2_data_block_index
+	call ext2_read_block
+
+	# calculate bytes to copy (min(block_size, remaining_bytes))
+	movl $EXT2_BLOCK_SIZE, %ecx
+	cmpl %ecx, 4(%esp)
+	cmovbl 4(%esp), %ecx
+
+	# update remaining read info
+	addl %ecx, 0(%esp)
+	subl %ecx, 4(%esp)
+
+	# very dumb memcpy with 32 bit addresses
+	movl $ext2_block_buffer, %esi
+	movl $0, %ebx
+ .ext2_inode_read_bytes_memcpy:
+	movb (%esi, %ebx), %al
+	movb %al, (%edi, %ebx)
+	incl %ebx
+	decl %ecx
+	jnz .ext2_inode_read_bytes_memcpy
+	addl %ebx, %edi
+
+	# read next block if more sectors remaining
+	cmpl $0, 4(%esp)
+	jnz .ext2_inode_read_bytes_no_partial_start
+
+ .ext2_inode_read_bytes_done:
+	leavel
+	popal
+	ret
+
+
+# find inode in inside directory inode stored in ext2_inode_buffer
+# store the found inode in ext2_inode_buffer
+#	si:		name string
+#	cx:		name length
+# return:
+#	eax:	ino if inode was found, 0 otherwise
+ext2_directory_find_inode:
+	pushl %ebx
+	pushw %cx
+	pushw %dx
+	pushw %si
+	pushw %di
+
+	pushl %ebp
+	movl %esp, %ebp
+	subl $8, %esp
+
+	# 0(%esp) := name length
+	movw %cx, 0(%esp)
+
+	# 2(%esp) := name string
+	movw %si, 2(%esp)
+
+	# verify that the name is <= 0xFF bytes
+	cmpw $0xFF, %cx
+	ja .ext2_directory_find_inode_not_found
+
+	# ebx := max data blocks: ceil(i_size / EXT2_BLOCK_SIZE)
+	movl (ext2_inode_buffer + i_size), %ebx
+	addl $EXT2_BLOCK_SHIFT, %ebx
+	decl %ebx
+	shrl $EXT2_BLOCK_SHIFT, %ebx
+	jz .ext2_directory_find_inode_not_found
+
+	# 4(%esp) := current block
+	movl $0, 4(%esp)
+
+ .ext2_directory_find_inode_block_read_loop:
+	# get next block index
+	movl 4(%esp), %eax
+	call ext2_data_block_index
+	test %eax, %eax
+	jz .ext2_directory_find_inode_next_block
+
+	# read current block
+	call ext2_read_block
+
+	# dx := current entry pointer
+	movw $ext2_block_buffer, %si
+
+ .ext2_directory_find_inode_loop_entries:
+	# temporarily store entry pointer in dx
+	movw %si, %dx
+
+	# check if name length matches
+	# cx := name length
+	movw 0(%esp), %cx
+	cmpb 6(%si), %cl
+	jne .ext2_directory_find_inode_next_entry
+
+	# si := entry name
+	addw $8, %si
+
+	# di := asked name
+	movw 2(%esp), %di
+
+	# check if name matches
+	call memcmp
+	test %al, %al
+	# NOTE: dx contains entry pointer
+	jnz .ext2_directory_find_inode_found
+
+ .ext2_directory_find_inode_next_entry:
+	# restore si
+	movw %dx, %si
+
+	# go to next entry if this block contains one
+	addw 4(%si), %si
+	cmpw $(ext2_block_buffer + EXT2_BLOCK_SIZE), %si
+	jb .ext2_directory_find_inode_loop_entries
+
+ .ext2_directory_find_inode_next_block:
+	incl 4(%esp)
+	cmpl %ebx, 4(%esp)
+	jb .ext2_directory_find_inode_block_read_loop
+
+ .ext2_directory_find_inode_not_found:
+	movb $0, %al
+	jmp .ext2_directory_find_inode_done
+
+ .ext2_directory_find_inode_found:
+	# extract ino and read it to ext2_inode_buffer
+	movw %dx, %si
+	movl 0(%si), %eax
+	call ext2_read_inode
+
+ .ext2_directory_find_inode_done:
+	leavel
+	popw %di
+	popw %si
+	popw %dx
+	popw %cx
+	popl %ebx
+	ret
+
+
+# search for kernel file from filesystem
+# returns only on success
+.global ext2_find_kernel
+ext2_find_kernel:
+	pushl %eax
+	pushw %cx
+	pushw %di
+	pushw %si
+
+	movl $EXT2_ROOT_INO, %eax
+	call ext2_read_inode
+
+	movw $kernel_path, %di
+ .ext2_find_kernel_loop:
+	movw (%di), %si
+
+	# check if this list is done
+	testw %si, %si
+	jz .ext2_find_kernel_loop_done
+
+	# check that current part is directory
+	movw (ext2_inode_buffer + i_mode), %ax
+	andw $EXT2_S_IMASK, %ax
+	cmpw $EXT2_S_IFDIR, %ax
+	jne .ext2_find_kernel_part_not_dir
+
+	# prepare registers for directory finding
+	movw 0(%si), %cx
+	addw $2, %si
+
+	# print search path
+	pushw %si
+	movw $ext2_looking_for_msg, %si
+	call puts
+	popw %si
+	call puts; call print_newline
+
+	# search current directory for this file
+	call ext2_directory_find_inode
+	testl %eax, %eax
+	jz .ext2_find_kernel_part_not_found
+
+	# loop to next part
+	addw $2, %di
+	jmp .ext2_find_kernel_loop
+
+ .ext2_find_kernel_loop_done:
+
+	# check that kernel is a regular file
+	movw (ext2_inode_buffer + i_mode), %ax
+	andw $EXT2_S_IMASK, %ax
+	cmpw $EXT2_S_IFREG, %ax
+	jne .ext2_find_kernel_not_reg
+
+	movw $ext2_kernel_found_msg, %si
+	call puts; call print_newline
+
+	popw %si
+	popw %di
+	popw %cx
+	popl %eax
+	ret
+
+ .ext2_find_kernel_part_not_dir:
+	movw $ext2_part_not_dir_msg, %si
+	jmp print_and_halt
+
+ .ext2_find_kernel_part_not_found:
+	movw $ext2_part_not_found_msg, %si
+	jmp print_and_halt
+
+ .ext2_find_kernel_not_reg:
+	movw $ext2_kernel_not_reg_msg, %si
+	jmp print_and_halt
+
+
+kernel_path:
+	.short kernel_path1
+	.short kernel_path2
+	.short 0
+kernel_path1:
+	.short 4
+	.asciz "boot"
+kernel_path2:
+	.short 15
+	.asciz "banan-os.kernel"
+
+
+root_partition_does_not_fit_ext2_filesystem_msg:
+	.asciz "Root partition is too small to contain ext2 filesystem"
+root_partition_has_invalid_ext2_magic_msg:
+	.asciz "Root partition doesn't contain ext2 magic number"
+root_partition_has_unsupported_ext2_block_size_msg:
+	.asciz "Root partition has unsupported ext2 block size (only 1024 supported)"
+
+ext2_part_not_dir_msg:
+	.asciz "inode in root path is not directory"
+ext2_part_not_found_msg:
+	.asciz " not found"
+ext2_kernel_not_reg_msg:
+	.asciz "kernel is not a regular file"
+ext2_kernel_found_msg:
+	.asciz "kernel found!"
+
+ext2_data_block_index_out_of_bounds_msg:
+	.asciz "data block index out of bounds"
+ext2_data_block_index_invalid_msg:
+	.asciz "data block index is invalid"
+
+ext2_looking_for_msg:
+	.asciz "looking for "
+
+.section .bss
+
+ext2_block_buffer:
+	.skip EXT2_BLOCK_SIZE
+
+ext2_partition_first_sector:
+	.skip 8
+
+ext2_drive_number:
+	.skip 1
+	.skip 3 # padding
+
+# NOTE: fits in 2 bytes
+ext2_inode_size:
+	.skip 4
+
+ext2_superblock_buffer:
+	.skip EXT2_SUPERBLOCK_SIZE
+
+ext2_block_group_descriptor_buffer:
+	.skip EXT2_BGD_SIZE
+
+ext2_inode_buffer:
+	.skip EXT2_INODE_SIZE_MAX

bootloader/bios/framebuffer.S

@@ -0,0 +1,156 @@
+.set TARGET_WIDTH,	800
+.set TARGET_HEIGHT,	600
+.set TARGET_BPP,	32
+
+.code16
+.section .stage2
+
+# Find suitable video mode
+# return:
+#	ax: video mode number if found, 0 otherwise
+.global vesa_find_video_mode
+vesa_find_video_mode:
+	pushw %ax
+	pushw %cx
+	pushw %di
+	pushl %esi
+
+	# clear target mode and frame buffer
+	movw $0, (vesa_target_mode)
+	movl $0, (framebuffer + 0)
+	movl $0, (framebuffer + 4)
+	movl $0, (framebuffer + 8)
+	movl $0, (framebuffer + 12)
+	movw $0, (framebuffer + 16)
+
+	# get vesa information
+	movw $0x4F00, %ax
+	movw $vesa_info_buffer, %di
+	int $0x10
+	cmpb $0x4F, %al; jne .vesa_unsupported
+	cmpb $0x00, %ah; jne .vesa_error
+
+	# confirm that response starts with 'VESA'
+	cmpl $0x41534556, (vesa_info_buffer)
+	jne .vesa_error
+
+	# confirm that version is atleast 2.0
+	cmpw $0x0200, (vesa_info_buffer + 0x04)
+	jb .vesa_unsupported_version
+
+	movl $(vesa_info_buffer + 0x0E), %esi
+	movl (%esi), %esi
+ .vesa_find_video_mode_loop_modes:
+	cmpw $0xFFFF, (%esi)
+	je .vesa_find_video_mode_loop_modes_done
+
+	# get info of next mode
+	movw $0x4F01, %ax
+	movw (%esi), %cx
+	movw $vesa_mode_info_buffer, %di
+	int $0x10
+	cmpb $0x4F, %al; jne .vesa_unsupported
+	cmpb $0x00, %ah; jne .vesa_error
+
+	# check whether in graphics mode
+	testb $0x10, (vesa_mode_info_buffer + 0)
+	jz .vesa_find_video_mode_next_mode
+
+	# compare mode's dimensions
+	cmpw $TARGET_WIDTH, (vesa_mode_info_buffer + 0x12)
+	jne .vesa_find_video_mode_next_mode
+	cmpw $TARGET_HEIGHT, (vesa_mode_info_buffer + 0x14)
+	jne .vesa_find_video_mode_next_mode
+	cmpb $TARGET_BPP, (vesa_mode_info_buffer + 0x19)
+	jne .vesa_find_video_mode_next_mode
+
+	movl (vesa_mode_info_buffer + 0x28), %esi
+	movl %esi,				(framebuffer + 0)
+	movw (vesa_mode_info_buffer + 0x10), %ax
+	movw %ax,				(framebuffer + 4)
+	movl $TARGET_WIDTH,		(framebuffer + 8)
+	movl $TARGET_HEIGHT,	(framebuffer + 12)
+	movb $TARGET_BPP,		(framebuffer + 16)
+	movb $1,				(framebuffer + 17)
+
+	movw %cx, (vesa_target_mode)
+	jmp .vesa_find_video_mode_loop_modes_done
+
+ .vesa_find_video_mode_next_mode:
+	addl $2, %esi
+	jmp .vesa_find_video_mode_loop_modes
+
+ .vesa_find_video_mode_loop_modes_done:
+	popl %esi
+	popw %di
+	popw %cx
+	popw %ax
+	ret
+
+ .vesa_unsupported:
+	movw $vesa_unsupported_msg, %si
+	jmp print_and_halt
+ .vesa_unsupported_version:
+	movw $vesa_unsupported_version_msg, %si
+	jmp print_and_halt
+ .vesa_error:
+	movw $vesa_error_msg, %si
+	jmp print_and_halt
+
+
+# set mode found from vesa_find_video_mode. if no mode
+# was found, set it to 80x25 text mode to clear the screen.
+.global vesa_set_target_mode
+vesa_set_target_mode:
+	pushw %ax
+	pushw %bx
+
+	movw (vesa_target_mode), %bx
+	testw %bx, %bx
+	jz .vesa_set_target_mode_generic	
+
+	movw $0x4F02, %ax
+	orw $0x4000, %bx
+	int $0x10
+
+	jmp .set_video_done
+
+ .vesa_set_target_mode_generic:
+	movb $0x03, %al
+	movb $0x00, %ah
+	int $0x10
+
+ .set_video_done:
+	popw %bx
+	popw %ax
+	ret
+
+
+vesa_error_msg:
+	.asciz "VESA error"
+vesa_unsupported_msg:
+	.asciz "VESA unsupported"
+vesa_unsupported_version_msg:
+	.asciz "VESA unsupported version"
+vesa_success_msg:
+	.asciz "VESA success"
+
+.section .bss
+
+vesa_info_buffer:
+	.skip 512
+
+vesa_mode_info_buffer:
+	.skip 256
+
+vesa_target_mode:
+	.skip 2
+
+.global framebuffer
+framebuffer:
+	.skip 4	# address
+	.skip 4	# pitch
+	.skip 4	# width
+	.skip 4 # height
+	.skip 1 # bpp
+	.skip 1 # type

bootloader/bios/linker.ld

@@ -0,0 +1,15 @@
+ENTRY(stage1_main)
+
+SECTIONS
+{
+	. = 0x7C00;
+	.stage1 : { *(.stage1) }
+
+	. = ALIGN(512);
+	stage2_start = .;
+	.stage2 : { *(.stage2) }
+	stage2_end = .;
+
+	. = ALIGN(512);
+	.bss : { *(.bss) }
+}

bootloader/bios/memory_map.S

@@ -0,0 +1,131 @@
+.code16
+
+.section .stage2
+
+# fills memory map data structure
+# doesn't return on error
+# NO REGISTERS SAVED
+.global get_memory_map
+get_memory_map:
+	movl $0, (memory_map_entry_count)
+
+	movl $0x0000E820, %eax
+	movl $0x534D4150, %edx
+	xorl %ebx, %ebx
+	movl $20, %ecx
+	movw $memory_map_entries, %di
+
+	clc
+	int $0x15
+	# If first call returs with CF set, the call failed
+	jc .get_memory_map_error
+
+ .get_memory_map_rest:
+	cmpl $0x534D4150, %eax
+	jne .get_memory_map_error
+
+	# FIXME: don't assume BIOS to always return 20 bytes
+	cmpl $20, %ecx
+	jne .get_memory_map_error
+
+	# increment entry count
+	incl (memory_map_entry_count)
+
+	# increment entry pointer
+	addw %cx, %di
+
+	# BIOS can indicate end of list by 0 in ebx
+	testl %ebx, %ebx
+	jz .get_memory_map_done
+
+	movl $0x0000E820, %eax
+	movl $0x534D4150, %edx
+
+	clc
+	int $0x15
+	# BIOS can indicate end of list by setting CF
+	jnc .get_memory_map_rest
+
+ .get_memory_map_done:
+	ret
+
+ .get_memory_map_error:
+	movw $memory_map_error_msg, %si
+	jmp print_and_halt
+
+
+# print memory map from memory_map_entries
+# NO REGISTERS SAVED
+.global print_memory_map
+print_memory_map:
+	movw $memory_map_msg, %si
+	call puts
+	call print_newline
+
+	movl (memory_map_entry_count), %edx
+	movw $memory_map_entries, %si
+
+	movw $16, %bx
+	movw $4, %cx
+
+ .loop_memory_map:
+	movb $' ', %al
+	call putc; call putc; call putc; call putc
+
+	movw 0x06(%si), %ax
+	call print_number
+	movw 0x04(%si), %ax
+	call print_number
+	movw 0x02(%si), %ax
+	call print_number
+	movw 0x00(%si), %ax
+	call print_number
+
+	movb $',', %al
+	call putc
+	movb $' ', %al
+	call putc
+
+	movw 0x0E(%si), %ax
+	call print_number
+	movw 0x0C(%si), %ax
+	call print_number
+	movw 0x0A(%si), %ax
+	call print_number
+	movw 0x08(%si), %ax
+	call print_number
+
+	movb $',', %al
+	call putc
+	movb $' ', %al
+	call putc
+
+	movw 0x12(%si), %ax
+	call print_number
+	movw 0x10(%si), %ax
+	call print_number
+
+	call print_newline
+
+	addw $20, %si
+
+	decl %edx
+	jnz .loop_memory_map
+
+	ret
+
+
+memory_map_msg:
+	.asciz "memmap:"
+memory_map_error_msg:
+	.asciz "Failed to get memory map"
+
+.section .bss
+
+.global memory_map
+memory_map:
+memory_map_entry_count:
+	.skip 4
+# 100 entries should be enough...
+memory_map_entries:
+	.skip 20 * 100

bootloader/bios/utils.S

@@ -0,0 +1,280 @@
+.set SCREEN_WIDTH,	80
+.set SCREEN_HEIGHT,	25
+
+.code16
+
+.section .stage1
+
+# prints character to screen
+# al:		ascii character to print
+.global putc
+putc:
+	pushw %ax
+	pushw %bx
+	movb $0x0E, %ah
+	xorb %bh, %bh
+	int $0x10
+	popw %bx
+	popw %ax
+	ret
+
+# prints null terminated string to screen
+# ds:si:	string address
+.global puts
+puts:
+	pushw %si
+	pushw %bx
+	pushw %ax
+
+	movb $0x0E, %ah
+	xorb %bh, %bh
+
+ .puts_loop:
+	lodsb
+
+	test %al, %al
+	jz .puts_done
+
+	int $0x10
+	jmp .puts_loop
+
+ .puts_done:
+	popw %ax
+	popw %bx
+	popw %si
+	ret
+
+# compares memory between addresses
+# si:		ptr1
+# di:		ptr2
+# cx:		bytes count
+# return:
+#	al: 1 if equal, 0 otherwise
+.global memcmp
+memcmp:
+	# NOTE: using pusha + popa to save space
+	pusha
+	cld
+	repe cmpsb
+	popa
+	setzb %al
+	ret
+
+
+.section .stage2
+
+# read a character from keyboard
+# return:
+#	al: ascii
+#	ah: bios scan code
+.global getc
+getc:
+	movb $0x00, %ah
+	int $0x16
+	ret
+
+# prints newline to screen
+.global print_newline
+print_newline:
+	pushw %ax
+	movb $'\r', %al
+	call putc
+	movb $'\n', %al
+	call putc
+	pop %ax
+	ret
+
+# prints backspace to screen, can go back a line
+.global print_backspace
+print_backspace:
+	pushw %ax
+	pushw %bx
+	pushw %cx
+	pushw %dx
+
+	# get cursor position
+	movb $0x03, %ah
+	movb $0x00, %bh
+	int $0x10
+
+	# don't do anyting if on first row
+	testb %dh, %dh
+	jz .print_backspace_done
+
+	# go one line up if on first column
+	test %dl, %dl
+	jz .print_backspace_go_line_up
+
+	# otherwise decrease column
+	decb %dl
+	jmp .print_backspace_do_print
+
+ .print_backspace_go_line_up:
+	# decrease row and set column to the last one
+	decb %dh
+	movb $(SCREEN_WIDTH - 1), %dl
+
+ .print_backspace_do_print:
+	# set cursor position
+	movb $0x02, %ah
+	int $0x10
+
+	# print 'empty' character (space)
+	mov $' ', %al
+	call putc
+
+	# set cursor position
+	movb $0x02, %ah
+	int $0x10
+
+ .print_backspace_done:
+	popw %dx
+	popw %cx
+	popw %bx
+	popw %ax
+	ret
+
+# print number to screen
+# ax:	number to print
+# bx:	number base
+# cx:	min width (zero pads if shorter)
+.global print_number
+print_number:
+	pusha
+	pushl %ebp
+	movl %esp, %ebp
+
+	# save min width
+	subl $4, %esp
+	movw %cx, (%esp)
+
+	movw $print_number_buffer, %si
+	xorw %cx, %cx
+
+ .print_number_fill_loop:
+	# fill buffer with all remainders ax % bx
+	xorw %dx, %dx
+	divw %bx
+	movb %dl, (%si)
+	incw %si
+	incw %cx
+	testw %ax, %ax
+	jnz .print_number_fill_loop
+
+	# check if zero pad is required
+	cmpw (%esp), %cx
+	jae .print_number_print_loop
+
+	# dx: saved number count
+	# cx: zero pad count
+	movw %cx, %dx
+	movw (%esp), %cx
+	subw %dx, %cx
+	movb $'0', %al
+
+ .print_number_pad_zeroes:
+	call putc
+	loop .print_number_pad_zeroes
+
+	# restore number count
+	movw %dx, %cx
+
+ .print_number_print_loop:
+	decw %si
+	movb (%si), %al
+	cmpb $10, %al
+	jae .print_number_hex
+	addb $'0', %al
+	jmp .print_number_do_print
+ .print_number_hex:
+	addb $('a' - 10), %al
+ .print_number_do_print:
+	call putc
+	loop .print_number_print_loop
+
+	leavel
+	popa
+	ret
+
+# prints 8 bit hexadecimal number to screen
+#	al:		number to print
+.global print_hex8
+print_hex8:
+	pushw %ax
+	pushw %bx
+	pushw %cx
+
+	movw $16, %bx
+	movw $2,  %cx
+	andw $0xFF, %ax
+	call print_number
+
+	popw %cx
+	popw %bx
+	popw %ax
+	ret
+
+# prints 16 bit hexadecimal number to screen
+#	ax:		number to print
+.global print_hex16
+print_hex16:
+	pushw %bx
+	pushw %cx
+
+	movw $16, %bx
+	movw $4,  %cx
+	call print_number
+
+	popw %cx
+	popw %bx
+	ret
+
+# prints 32 bit hexadecimal number to screen
+#	eax:	number to print
+.global print_hex32
+print_hex32:
+	pushl %eax
+	pushw %dx
+
+	movw %ax, %dx
+
+	shrl $16, %eax;
+	call print_hex16
+
+	movw %dx, %ax
+	call print_hex16
+
+	popw %dx
+	popl %eax
+	ret
+
+# prints 64 bit hexadecimal number to screen
+#	edx:eax:	number to print
+.global print_hex64
+print_hex64:
+	xchgl %eax, %edx
+	call print_hex32
+	xchgl %eax, %edx
+	call print_hex32
+	ret
+
+# test if character is printable ascii
+#	al: character to test
+# return:
+#	al: 1 if is printable, 0 otherwise
+.global isprint
+isprint:
+	subb $0x20, %al
+	cmpb $(0x7E - 0x20), %al
+	ja .isprint_not_printable
+	movb $1, %al
+	ret
+ .isprint_not_printable:
+	movb $0, %al
+	ret
+
+.section .bss
+
+# enough for base 2 printing
+print_number_buffer:
+	.skip 16

bootloader/installer/.gitignore

@@ -0,0 +1 @@
+build/

bootloader/installer/CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(x86_64-banan_os-bootloader-installer CXX)
+
+set(SOURCES
+    crc32.cpp
+    ELF.cpp
+    GPT.cpp
+    GUID.cpp
+	main.cpp
+)
+
+add_executable(x86_64-banan_os-bootloader-installer ${SOURCES})
+target_compile_options(x86_64-banan_os-bootloader-installer PRIVATE -O2 -std=c++20)
+target_compile_definitions(x86_64-banan_os-bootloader-installer PRIVATE __arch=x86_64)
+target_include_directories(x86_64-banan_os-bootloader-installer PRIVATE ${CMAKE_SOURCE_DIR}/../../LibELF/include)
+target_include_directories(x86_64-banan_os-bootloader-installer PRIVATE ${CMAKE_SOURCE_DIR}/../../kernel/include)

bootloader/installer/ELF.cpp

@@ -0,0 +1,142 @@
+#include "ELF.h"
+
+#include <LibELF/Values.h>
+
+#include <cassert>
+#include <cerrno>
+#include <cstring>
+#include <fcntl.h>
+#include <iostream>
+#include <sys/mman.h>
+#include <unistd.h>
+
+using namespace LibELF;
+
+ELFFile::ELFFile(std::string_view path)
+	: m_path(path)
+{
+	m_fd = open(m_path.c_str(), O_RDONLY);
+	if (m_fd == -1)
+	{
+		std::cerr << "Could not open '" << m_path << "': " << std::strerror(errno) << std::endl;
+		return;
+	}
+
+	if (fstat(m_fd, &m_stat) == -1)
+	{
+		std::cerr << "Could not stat '" << m_path << "': " << std::strerror(errno) << std::endl;
+		return;
+	}
+
+	void* mmap_addr = mmap(nullptr, m_stat.st_size, PROT_READ, MAP_PRIVATE, m_fd, 0);
+	if (mmap_addr == MAP_FAILED)
+	{
+		std::cerr << "Could not mmap '" << m_path << "': " << std::strerror(errno) << std::endl;
+		return;
+	}
+	m_mmap = reinterpret_cast<uint8_t*>(mmap_addr);
+
+	if (!validate_elf_header())
+		return;
+
+	m_success = true;
+}
+
+ELFFile::~ELFFile()
+{
+	if (m_mmap)
+		munmap(m_mmap, m_stat.st_size);
+	m_mmap = nullptr;
+
+	if (m_fd != -1)
+		close(m_fd);
+	m_fd = -1;
+}
+
+const ElfNativeFileHeader& ELFFile::elf_header() const
+{
+	return *reinterpret_cast<LibELF::ElfNativeFileHeader*>(m_mmap);
+}
+
+bool ELFFile::validate_elf_header() const
+{
+	if (m_stat.st_size < sizeof(ElfNativeFileHeader))
+	{
+		std::cerr << m_path << " is too small to be a ELF executable" << std::endl;
+		return false;
+	}
+
+	const auto& elf_header = this->elf_header();
+
+	if (
+		elf_header.e_ident[EI_MAG0] != ELFMAG0 ||
+		elf_header.e_ident[EI_MAG1] != ELFMAG1 ||
+		elf_header.e_ident[EI_MAG2] != ELFMAG2 ||
+		elf_header.e_ident[EI_MAG3] != ELFMAG3
+	)
+	{
+		std::cerr << m_path << " doesn't have an ELF magic number" << std::endl;
+		return false;
+	}
+
+#if ARCH(x86_64)
+	if (elf_header.e_ident[EI_CLASS] != ELFCLASS64)
+#elif ARCH(i386)
+	if (elf_header.e_ident[EI_CLASS] != ELFCLASS32)
+#endif
+	{
+		std::cerr << m_path << " architecture doesn't match" << std::endl;
+		return false;
+	}
+
+	if (elf_header.e_ident[EI_DATA] != ELFDATA2LSB)
+	{
+		std::cerr << m_path << " is not in little endian format" << std::endl;
+		return false;
+	}
+
+	if (elf_header.e_ident[EI_VERSION] != EV_CURRENT)
+	{
+		std::cerr << m_path << " has unsupported version" << std::endl;
+		return false;
+	}
+
+	if (elf_header.e_type != ET_EXEC)
+	{
+		std::cerr << m_path << " is not an executable ELF file" << std::endl;
+		return false;
+	}
+
+	return true;
+}
+
+const ElfNativeSectionHeader& ELFFile::section_header(std::size_t index) const
+{
+	const auto& elf_header = this->elf_header();
+	assert(index < elf_header.e_shnum);
+	const uint8_t* section_array_start = m_mmap + elf_header.e_shoff;
+	return *reinterpret_cast<const ElfNativeSectionHeader*>(section_array_start + index * elf_header.e_shentsize);
+}
+
+std::string_view ELFFile::section_name(const ElfNativeSectionHeader& section_header) const
+{
+	const auto& elf_header = this->elf_header();
+	assert(elf_header.e_shstrndx != SHN_UNDEF);
+	const auto& section_string_table = this->section_header(elf_header.e_shstrndx);
+	const char* string_table_start = reinterpret_cast<const char*>(m_mmap + section_string_table.sh_offset);
+	return string_table_start + section_header.sh_name;
+}
+
+std::optional<std::span<const uint8_t>> ELFFile::find_section(std::string_view name) const
+{
+	const auto& elf_header = this->elf_header();
+	for (std::size_t i = 0; i < elf_header.e_shnum; i++)
+	{
+		const auto& section_header = this->section_header(i);
+		auto section_name = this->section_name(section_header);
+		if (section_name != name)
+			continue;
+		return std::span<const uint8_t>(m_mmap + section_header.sh_offset, section_header.sh_size);
+	}
+	return {};
+}

bootloader/installer/ELF.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <LibELF/Types.h>
+
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <string_view>
+#include <string>
+#include <sys/stat.h>
+
+class ELFFile
+{
+public:
+	ELFFile(std::string_view path);
+	~ELFFile();
+
+	const LibELF::ElfNativeFileHeader& elf_header() const;
+	std::optional<std::span<const uint8_t>> find_section(std::string_view name) const;
+
+	bool success() const { return m_success; }
+
+	std::string_view path() const { return m_path; }
+
+private:
+	const LibELF::ElfNativeSectionHeader& section_header(std::size_t index) const;
+	std::string_view section_name(const LibELF::ElfNativeSectionHeader&) const;
+	bool validate_elf_header() const;
+
+private:
+	const std::string	m_path;
+	bool				m_success	{ false };
+	int					m_fd		{ -1 };
+	struct stat			m_stat		{ };
+	uint8_t*			m_mmap		{ nullptr };
+};

bootloader/installer/GPT.cpp

@@ -0,0 +1,246 @@
+#include "crc32.h"
+#include "GPT.h"
+
+#include <cassert>
+#include <cerrno>
+#include <cstring>
+#include <fcntl.h>
+#include <iostream>
+#include <sys/mman.h>
+#include <unistd.h>
+
+// FIXME: don't assume 512 byte sectors
+#define SECTOR_SIZE 512
+
+GPTFile::GPTFile(std::string_view path)
+	: m_path(path)
+{
+	m_fd = open(m_path.c_str(), O_RDWR);
+	if (m_fd == -1)
+	{
+		std::cerr << "Could not open '" << m_path << "': " << std::strerror(errno) << std::endl;
+		return;
+	}
+
+	if (fstat(m_fd, &m_stat) == -1)
+	{
+		std::cerr << "Could not stat '" << m_path << "': " << std::strerror(errno) << std::endl;
+		return;
+	}
+
+	void* mmap_addr = mmap(nullptr, m_stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, m_fd, 0);
+	if (mmap_addr == MAP_FAILED)
+	{
+		std::cerr << "Could not mmap '" << m_path << "': " << std::strerror(errno) << std::endl;
+		return;
+	}
+	m_mmap = reinterpret_cast<uint8_t*>(mmap_addr);
+
+	if (!validate_gpt_header())
+		return;
+
+	m_success = true;
+}
+
+GPTFile::~GPTFile()
+{
+	if (m_mmap)
+		munmap(m_mmap, m_stat.st_size);
+	m_mmap = nullptr;
+
+	if (m_fd != -1)
+		close(m_fd);
+	m_fd = -1;
+}
+
+MBR& GPTFile::mbr()
+{
+	return *reinterpret_cast<MBR*>(m_mmap);
+}
+
+const GPTHeader& GPTFile::gpt_header() const
+{
+    return *reinterpret_cast<GPTHeader*>(m_mmap + SECTOR_SIZE);
+}
+
+bool GPTFile::install_stage1(std::span<const uint8_t> stage1)
+{
+	auto& mbr = this->mbr();
+
+	if (stage1.size() > sizeof(mbr.boot_code))
+	{
+		std::cerr << m_path << ": can't fit " << stage1.size() << " bytes of boot code in mbr (max is " << sizeof(mbr.boot_code) << ")" << std::endl;
+		return false;
+	}
+
+	// copy boot code
+	memcpy(mbr.boot_code, stage1.data(), stage1.size());
+
+	// setup mbr
+	mbr.unique_mbr_disk_signature = 0xdeadbeef;
+	mbr.unknown = 0;
+	mbr.signature = 0xAA55;
+
+	// setup mbr partition records
+	mbr.partition_records[0].boot_indicator = 0x00;
+	mbr.partition_records[0].starting_chs[0] = 0x00;
+	mbr.partition_records[0].starting_chs[1] = 0x02;
+	mbr.partition_records[0].starting_chs[2] = 0x00;
+	mbr.partition_records[0].os_type = 0xEE;
+	mbr.partition_records[0].ending_chs[0] = 0xFF;
+	mbr.partition_records[0].ending_chs[1] = 0xFF;
+	mbr.partition_records[0].ending_chs[2] = 0xFF;
+	mbr.partition_records[0].starting_lba = 1;
+	mbr.partition_records[0].size_in_lba = 0xFFFFFFFF;
+	memset(&mbr.partition_records[1], 0x00, sizeof(MBRPartitionRecord));
+	memset(&mbr.partition_records[2], 0x00, sizeof(MBRPartitionRecord));
+	memset(&mbr.partition_records[3], 0x00, sizeof(MBRPartitionRecord));
+
+	return true;
+}
+
+bool GPTFile::install_stage2(std::span<const uint8_t> stage2, const GUID& root_partition_guid)
+{
+	if (stage2.size() < 16)
+	{
+		std::cerr << m_path << ": contains invalid .stage2 section, too small for patches" << std::endl;
+		return false;
+	}
+
+	// find GUID patch offsets
+	std::size_t disk_guid_offset(-1);
+	std::size_t part_guid_offset(-1);
+	for (std::size_t i = 0; i < stage2.size() - 16; i++)
+	{
+		if (memcmp(stage2.data() + i, "root disk guid  ", 16) == 0)
+		{
+			if (disk_guid_offset != std::size_t(-1))
+			{
+				std::cerr << m_path << ": contains invalid .stage2 section, multiple patchable disk guids" << std::endl;
+				return false;
+			}
+			disk_guid_offset = i;
+		}
+		if (memcmp(stage2.data() + i, "root part guid  ", 16) == 0)
+		{
+			if (part_guid_offset != std::size_t(-1))
+			{
+				std::cerr << m_path << ": contains invalid .stage2 section, multiple patchable partition guids" << std::endl;
+				return false;
+			}
+			part_guid_offset = i;
+		}
+	}
+	if (disk_guid_offset == std::size_t(-1))
+	{
+		std::cerr << m_path << ": contains invalid .stage2 section, no patchable disk guid" << std::endl;
+		return false;
+	}
+	if (part_guid_offset == std::size_t(-1))
+	{
+		std::cerr << m_path << ": contains invalid .stage2 section, no patchable partition guid" << std::endl;
+		return false;
+	}
+	
+
+	auto partition = find_partition_with_type(bios_boot_guid);
+	if (!partition.has_value())
+	{
+		std::cerr << m_path << ": could not find partition with type " << bios_boot_guid << std::endl;
+		return false;
+	}
+
+	const std::size_t partition_size = (partition->ending_lba - partition->starting_lba + 1) * SECTOR_SIZE;
+
+	if (stage2.size() > partition_size)
+	{
+		std::cerr << m_path << ": can't fit " << stage2.size() << " bytes of data to partition of size " << partition_size << std::endl;
+		return false;
+	}
+
+	uint8_t* partition_start = m_mmap + partition->starting_lba * SECTOR_SIZE;
+	memcpy(partition_start, stage2.data(), stage2.size());
+
+	// patch GUIDs
+	*reinterpret_cast<GUID*>(partition_start + disk_guid_offset) = gpt_header().disk_guid;
+	*reinterpret_cast<GUID*>(partition_start + part_guid_offset) = root_partition_guid;
+
+	return true;
+}
+
+bool GPTFile::install_bootloader(std::span<const uint8_t> stage1, std::span<const uint8_t> stage2, const GUID& root_partition_guid)
+{
+	if (!find_partition_with_guid(root_partition_guid).has_value())
+	{
+		std::cerr << m_path << ": no partition with GUID " << root_partition_guid << std::endl;
+		return false;
+	}
+	if (!install_stage1(stage1))
+		return false;
+	if (!install_stage2(stage2, root_partition_guid))
+		return false;
+	return true;
+}
+
+std::optional<GPTPartitionEntry> GPTFile::find_partition_with_guid(const GUID& guid) const
+{
+	const auto& gpt_header = this->gpt_header();
+	const uint8_t* partition_entry_array_start = m_mmap + gpt_header.partition_entry_lba * SECTOR_SIZE;
+	for (std::size_t i = 0; i < gpt_header.number_of_partition_entries; i++)
+	{
+		const auto& partition_entry = *reinterpret_cast<const GPTPartitionEntry*>(partition_entry_array_start + i * gpt_header.size_of_partition_entry);
+		if (partition_entry.partition_guid != guid)
+			continue;
+		return partition_entry;
+	}
+	return {};
+}
+
+std::optional<GPTPartitionEntry> GPTFile::find_partition_with_type(const GUID& type_guid) const
+{
+	const auto& gpt_header = this->gpt_header();
+	const uint8_t* partition_entry_array_start = m_mmap + gpt_header.partition_entry_lba * SECTOR_SIZE;
+	for (std::size_t i = 0; i < gpt_header.number_of_partition_entries; i++)
+	{
+		const auto& partition_entry = *reinterpret_cast<const GPTPartitionEntry*>(partition_entry_array_start + i * gpt_header.size_of_partition_entry);
+		if (partition_entry.type_guid != type_guid)
+			continue;
+		return partition_entry;
+	}
+	return {};
+}
+
+bool GPTFile::validate_gpt_header() const
+{
+    if (SECTOR_SIZE + m_stat.st_size < sizeof(GPTHeader))
+    {
+		std::cerr << m_path << " is too small to have GPT header" << std::endl;
+        return false;
+    }
+
+    auto gpt_header = this->gpt_header();
+
+    if (std::memcmp(gpt_header.signature, "EFI PART", 8) != 0)
+    {
+		std::cerr << m_path << " doesn't contain GPT partition header signature" << std::endl;
+		return false;
+    }
+
+	const uint32_t header_crc32 = gpt_header.header_crc32;
+
+	gpt_header.header_crc32 = 0;
+	if (header_crc32 != crc32_checksum(reinterpret_cast<uint8_t*>(&gpt_header), gpt_header.header_size))
+	{
+		std::cerr << m_path << " has non-matching header crc32" << std::endl;
+		return false;
+	}
+
+	const std::size_t partition_array_size = gpt_header.number_of_partition_entries * gpt_header.size_of_partition_entry;
+	if (gpt_header.partition_entry_array_crc32 != crc32_checksum(m_mmap + gpt_header.partition_entry_lba * SECTOR_SIZE, partition_array_size))
+	{
+		std::cerr << m_path << " has non-matching partition entry crc32" << std::endl;
+		return false;
+	}
+
+    return true;
+}

bootloader/installer/GPT.h

@@ -0,0 +1,91 @@
+#pragma once
+
+#include "GUID.h"
+
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <string_view>
+#include <string>
+#include <sys/stat.h>
+
+struct MBRPartitionRecord
+{
+	uint8_t boot_indicator;
+	uint8_t starting_chs[3];
+	uint8_t os_type;
+	uint8_t ending_chs[3];
+	uint32_t starting_lba;
+	uint32_t size_in_lba;
+} __attribute__((packed));
+
+struct MBR
+{
+	uint8_t boot_code[440];
+	uint32_t unique_mbr_disk_signature;
+	uint16_t unknown;
+	MBRPartitionRecord partition_records[4];
+	uint16_t signature;
+} __attribute__((packed));
+static_assert(sizeof(MBR) == 512);
+
+struct GPTPartitionEntry
+{
+	GUID type_guid;
+	GUID partition_guid;
+	uint64_t starting_lba;
+	uint64_t ending_lba;
+	uint64_t attributes;
+	uint16_t name[36];
+};
+static_assert(sizeof(GPTPartitionEntry) == 128);
+
+struct GPTHeader
+{
+	char signature[8];
+	uint32_t revision;
+	uint32_t header_size;
+	uint32_t header_crc32;
+	uint32_t reserved;
+	uint64_t my_lba;
+	uint64_t alternate_lba;
+	uint64_t first_usable_lba;
+	uint64_t last_usable_lba;
+	GUID disk_guid;
+	uint64_t partition_entry_lba;
+	uint32_t number_of_partition_entries;
+	uint32_t size_of_partition_entry;
+	uint32_t partition_entry_array_crc32;
+} __attribute__((packed));
+static_assert(sizeof(GPTHeader) == 92);
+
+class GPTFile
+{
+public:
+	GPTFile(std::string_view path);
+	~GPTFile();
+
+	bool install_bootloader(std::span<const uint8_t> stage1, std::span<const uint8_t> stage2, const GUID& root_partition_guid);
+
+	const GPTHeader& gpt_header() const;
+
+	bool success() const { return m_success; }
+
+	std::string_view path() const { return m_path; }
+
+private:
+	MBR& mbr();
+	bool validate_gpt_header() const;
+	std::optional<GPTPartitionEntry> find_partition_with_guid(const GUID& guid) const;
+	std::optional<GPTPartitionEntry> find_partition_with_type(const GUID& type_guid) const;
+
+	bool install_stage1(std::span<const uint8_t> stage1);
+	bool install_stage2(std::span<const uint8_t> stage2, const GUID& root_partition_guid);
+
+private:
+	const std::string	m_path;
+	bool				m_success	{ false };
+	int					m_fd		{ -1 };
+	struct stat			m_stat		{ };
+	uint8_t*			m_mmap		{ nullptr };
+};

bootloader/installer/GUID.cpp

@@ -0,0 +1,74 @@
+#include "GUID.h"
+
+#include <iomanip>
+#include <cstring>
+
+std::optional<uint64_t> parse_hex(std::string_view hex_string)
+{
+	uint64_t result = 0;
+	for (char c : hex_string)
+	{
+		if (!isxdigit(c))
+			return {};
+
+		uint8_t nibble = 0;
+		if ('0' <= c && c <= '9')
+			nibble = c - '0';
+		else if ('a' <= c && c <= 'f')
+			nibble = c - 'a' + 10;
+		else
+			nibble = c - 'A' + 10;
+		result = (result << 4) | nibble;
+	}
+	return result;
+}
+
+std::optional<GUID> GUID::from_string(std::string_view guid_string)
+{
+	if (guid_string.size() != 36)
+		return {};
+
+	if (guid_string[8] != '-' || guid_string[13] != '-' || guid_string[18] != '-' || guid_string[23] != '-')
+		return {};
+
+	auto comp1 = parse_hex(guid_string.substr(0, 8));
+	auto comp2 = parse_hex(guid_string.substr(9, 4));
+	auto comp3 = parse_hex(guid_string.substr(14, 4));
+	auto comp4 = parse_hex(guid_string.substr(19, 4));
+	auto comp5 = parse_hex(guid_string.substr(24, 12));
+
+	if (!comp1.has_value() || !comp2.has_value() || !comp3.has_value() || !comp4.has_value() || !comp5.has_value())
+		return {};
+
+	GUID result;
+	result.component1 = *comp1;
+	result.component2 = *comp2;
+	result.component3 = *comp3;
+	for (int i = 0; i < 2; i++)
+		result.component45[i + 0] = *comp4 >> ((2-1) * 8 - i * 8);
+	for (int i = 0; i < 6; i++)
+		result.component45[i + 2] = *comp5 >> ((6-1) * 8 - i * 8);
+	return result;
+}
+
+bool GUID::operator==(const GUID& other) const
+{
+	return std::memcmp(this, &other, sizeof(GUID)) == 0;
+}
+
+std::ostream& operator<<(std::ostream& out, const GUID& guid)
+{
+	auto flags = out.flags();
+	out << std::hex << std::setfill('0');
+	out << std::setw(8) << guid.component1 << '-';
+	out << std::setw(4) << guid.component2 << '-';
+	out << std::setw(4) << guid.component3 << '-';
+
+	out << std::setw(2);
+	for (int i = 0; i < 2; i++) out << +guid.component45[i];
+	out << '-';
+	for (int i = 2; i < 8; i++) out << +guid.component45[i];
+
+	out.flags(flags);
+	return out;
+}

bootloader/installer/GUID.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <ostream>
+#include <string_view>
+
+struct GUID
+{
+	static std::optional<GUID> from_string(std::string_view);
+
+	uint32_t component1;
+	uint16_t component2;
+	uint16_t component3;
+	// last 2 components are combined so no packed needed
+	uint8_t component45[8];
+
+	bool operator==(const GUID& other) const;
+};
+
+std::ostream& operator<<(std::ostream& out, const GUID& guid);
+
+// unused		00000000-0000-0000-0000-000000000000
+static constexpr GUID unused_guid = {
+	0x00000000,
+	0x0000,
+	0x0000,
+	{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
+};
+
+// bios boot	21686148-6449-6E6F-744E-656564454649
+static constexpr GUID bios_boot_guid = {
+	0x21686148,
+	0x6449,
+	0x6E6F,
+	{ 0x74, 0x4E, 0x65, 0x65, 0x64, 0x45, 0x46, 0x49 }
+};

bootloader/installer/build.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+g++ -O2 -std=c++20 main.cpp crc32.cpp ELF.cpp GPT.cpp GUID.cpp -o install-bootloader

bootloader/installer/crc32.cpp

@@ -0,0 +1,80 @@
+#include "crc32.h"
+
+static constexpr uint32_t crc32_table[256] =
+{
+	0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
+	0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
+	0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
+	0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
+	0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
+	0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
+	0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
+	0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
+	0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
+	0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
+	0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
+	0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
+	0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
+	0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
+	0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
+	0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
+	0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
+	0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
+	0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
+	0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
+	0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
+	0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
+	0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
+	0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
+	0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
+	0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
+	0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
+	0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
+	0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
+	0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
+	0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
+	0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
+	0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
+	0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
+	0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
+	0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
+	0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
+	0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
+	0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
+	0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
+	0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
+	0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
+	0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
+	0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
+	0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
+	0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
+	0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
+	0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
+	0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
+	0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
+	0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
+	0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
+	0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
+	0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
+	0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
+	0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
+	0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
+	0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
+	0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
+	0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
+	0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
+	0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
+	0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
+	0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
+};
+
+uint32_t crc32_checksum(const uint8_t* data, std::size_t count)
+{
+	uint32_t crc32 = 0xFFFFFFFF;
+	for (size_t i = 0; i < count; i++)
+	{
+		uint8_t index = (crc32 ^ data[i]) & 0xFF;
+		crc32 = (crc32 >> 8) ^ crc32_table[index];
+	}
+	return crc32 ^ 0xFFFFFFFF;
+}

bootloader/installer/crc32.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+uint32_t crc32_checksum(const uint8_t* data, std::size_t count);

bootloader/installer/main.cpp

@@ -0,0 +1,44 @@
+#include "ELF.h"
+#include "GPT.h"
+
+#include <iostream>
+
+int main(int argc, char** argv)
+{
+	using namespace std::string_view_literals;
+
+	if (argc != 4)
+	{
+		std::fprintf(stderr, "usage: %s BOOTLOADER DISK_IMAGE ROOT_PARTITION_GUID\n", argv[0]);
+		return 1;
+	}
+
+	auto root_partition_guid = GUID::from_string(argv[3]);
+	if (!root_partition_guid.has_value())
+	{
+		std::cerr << "invalid guid '" << argv[3] << '\'' << std::endl;
+		return 1;
+	}
+
+	ELFFile bootloader(argv[1]);
+	if (!bootloader.success())
+		return 1;
+
+	auto stage1 = bootloader.find_section(".stage1"sv);
+	auto stage2 = bootloader.find_section(".stage2"sv);
+	if (!stage1.has_value() || !stage2.has_value())
+	{
+		std::cerr << bootloader.path() << " doesn't contain .stage1 and .stage2 sections" << std::endl;
+		return 1;
+	}
+
+	GPTFile disk_image(argv[2]);
+	if (!disk_image.success())
+		return 1;
+
+	if (!disk_image.install_bootloader(*stage1, *stage2, *root_partition_guid))
+		return 1;
+	std::cout << "bootloader installed" << std::endl;
+
+	return 0;
+}

bos

@@ -0,0 +1 @@
+script/build.sh

build.sh

@@ -1,7 +0,0 @@
-#!/bin/sh
-set -e
-. ./headers.sh
- 
-for PROJECT in $PROJECTS; do
-  (cd $PROJECT && DESTDIR="$SYSROOT" $MAKE install)
-done

clean.sh

@@ -1,11 +0,0 @@
-#!/bin/sh
-set -e
-. ./config.sh
- 
-for PROJECT in $PROJECTS; do
-  (cd $PROJECT && $MAKE clean)
-done
- 
-rm -rf sysroot
-rm -rf isodir
-rm -rf banan-os.img

config.sh

@@ -1,33 +0,0 @@
-SYSTEM_HEADER_PROJECTS="libc BAN kernel"
-PROJECTS="libc BAN kernel"
- 
-export MAKE=${MAKE:-make}
-export HOST=${HOST:-$(./default-host.sh)}
- 
-export AR=${HOST}-ar
-export AS=${HOST}-as
-export CC=${HOST}-gcc
-export CXX=${HOST}-g++
- 
-export PREFIX=/usr
-export EXEC_PREFIX=$PREFIX
-export BOOTDIR=/boot
-export LIBDIR=$EXEC_PREFIX/lib
-export INCLUDEDIR=$PREFIX/include
- 
-export CFLAGS='-O2 -g'
-export CPPFLAGS='--std=c++20 -Wno-literal-suffix'
- 
-export UBSAN=0
-
-# Configure the cross-compiler to use the desired system root.
-export SYSROOT="$(pwd)/sysroot"
-export CC="$CC --sysroot=$SYSROOT"
-export CXX="$CXX --sysroot=$SYSROOT"
- 
-# Work around that the -elf gcc targets doesn't have a system include directory
-# because it was configured with --without-headers rather than --with-sysroot.
-if echo "$HOST" | grep -Eq -- '-elf($|-)'; then
-  export CC="$CC -isystem=$INCLUDEDIR"
-  export CXX="$CXX -isystem=$INCLUDEDIR"
-fi

default-host.sh

@@ -1,2 +0,0 @@
-#!/bin/sh
-echo x86_64-elf

disk.sh

@@ -1,67 +0,0 @@
-#!/bin/sh
-set -e
-. ./build.sh
-
-DISK_NAME=banan-os.img
-DISK_SIZE=$[50 * 1024 * 1024]
-MOUNT_DIR=/mnt
-
-dd if=/dev/zero of=$DISK_NAME bs=512 count=$[$DISK_SIZE / 512]
-
-sed -e 's/\s*\([-\+[:alnum:]]*\).*/\1/' << EOF | fdisk $DISK_NAME
-  g     # gpt
-  n     # new partition
-  1     # partition number 1
-        # default (from the beginning of the disk)
-  +1MiB # bios boot partiton size
-  n     # new partition
-  2     # partition number 2
-        # default (right after bios boot partition)
-		# default (to the end of disk)
-  t     # set type
-  1     # ... of partition 1
-  4     # bios boot partition
-  t     # set type
-  2     # ... of partition 2
-  20    # Linux filesystem
-  x		# expert menu
-  n		# partition name
-  2		# ... of partition 2
-  banan-root
-  r		# back to main menu
-  w     # write changes
-EOF
-
-LOOP_DEV=$(sudo losetup -f --show $DISK_NAME)
-sudo partprobe $LOOP_DEV
-
-PARTITION1=${LOOP_DEV}p1
-PARTITION2=${LOOP_DEV}p2
-
-sudo mkfs.ext2 $PARTITION2
-
-sudo mount $PARTITION2 $MOUNT_DIR
-
-sudo cp -r ${SYSROOT}/* ${MOUNT_DIR}/
-sudo mkdir -p ${MOUNT_DIR}/usr/share/
-sudo cp -r fonts ${MOUNT_DIR}/usr/share/
-
-sudo grub-install --no-floppy --target=i386-pc --modules="normal ext2 multiboot" --boot-directory=${MOUNT_DIR}/boot $LOOP_DEV
-
-echo -e '
-menuentry "banan-os" {
-	multiboot /boot/banan-os.kernel
-}
-menuentry "banan-os (no serial)" {
-	multiboot /boot/banan-os.kernel noserial
-}
-menuentry "banan-os (no apic)" {
-	multiboot /boot/banan-os.kernel noapic
-}
-menuentry "banan-os (no apic, no serial)" {
-	multiboot /boot/banan-os.kernel noapic noserial
-}
-' | sudo tee ${MOUNT_DIR}/boot/grub/grub.cfg
-
-sudo umount $MOUNT_DIR
-sudo losetup -d $LOOP_DEV

headers.sh

@@ -1,9 +0,0 @@
-#!/bin/sh
-set -e
-. ./config.sh
- 
-mkdir -p "$SYSROOT"
- 
-for PROJECT in $SYSTEM_HEADER_PROJECTS; do
-  (cd $PROJECT && DESTDIR="$SYSROOT" $MAKE install-headers)
-done

install-usb.sh

@@ -1,8 +0,0 @@
-#!/bin/sh
-set -e
-. ./disk.sh
-
-SIZE=$(stat -c '%s' banan-os.img | numfmt --to=iec)
-
-echo Writing ${SIZE}iB
-sudo dd if=banan-os.img of=/dev/sda status=progress

kernel/.gitignore

@@ -1,3 +0,0 @@
-*.d
-*.kernel
-*.o

kernel/CMakeLists.txt

@@ -0,0 +1,200 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(kernel CXX C ASM)
+
+if("${BANAN_ARCH}" STREQUAL "x86_64")
+	set(ELF_FORMAT elf64-x86-64)
+elseif("${BANAN_ARCH}" STREQUAL "i386")
+	set(ELF_FORMAT elf32-i386)
+endif()
+
+set(KERNEL_SOURCES
+	font/prefs.psf.o
+	kernel/ACPI.cpp
+	kernel/APIC.cpp
+	kernel/BootInfo.cpp
+	kernel/CPUID.cpp
+	kernel/Debug.cpp
+	kernel/Device/Device.cpp
+	kernel/Device/NullDevice.cpp
+	kernel/Device/ZeroDevice.cpp
+	kernel/Errors.cpp
+	kernel/Font.cpp
+	kernel/FS/DevFS/FileSystem.cpp
+	kernel/FS/Ext2/FileSystem.cpp
+	kernel/FS/Ext2/Inode.cpp
+	kernel/FS/Inode.cpp
+	kernel/FS/Pipe.cpp
+	kernel/FS/ProcFS/FileSystem.cpp
+	kernel/FS/ProcFS/Inode.cpp
+	kernel/FS/TmpFS/FileSystem.cpp
+	kernel/FS/TmpFS/Inode.cpp
+	kernel/FS/VirtualFileSystem.cpp
+	kernel/Input/PS2Controller.cpp
+	kernel/Input/PS2Keyboard.cpp
+	kernel/Input/PS2Keymap.cpp
+	kernel/InterruptController.cpp
+	kernel/kernel.cpp
+	kernel/Memory/DMARegion.cpp
+	kernel/Memory/FileBackedRegion.cpp
+	kernel/Memory/Heap.cpp
+	kernel/Memory/kmalloc.cpp
+	kernel/Memory/MemoryBackedRegion.cpp
+	kernel/Memory/MemoryRegion.cpp
+	kernel/Memory/PhysicalRange.cpp
+	kernel/Memory/VirtualRange.cpp
+	kernel/Networking/E1000.cpp
+	kernel/OpenFileDescriptorSet.cpp
+	kernel/Panic.cpp
+	kernel/PCI.cpp
+	kernel/PIC.cpp
+	kernel/Process.cpp
+	kernel/Scheduler.cpp
+	kernel/Semaphore.cpp
+	kernel/SpinLock.cpp
+	kernel/SSP.cpp
+	kernel/Storage/ATA/AHCI/Controller.cpp
+	kernel/Storage/ATA/AHCI/Device.cpp
+	kernel/Storage/ATA/ATABus.cpp
+	kernel/Storage/ATA/ATAController.cpp
+	kernel/Storage/ATA/ATADevice.cpp
+	kernel/Storage/DiskCache.cpp
+	kernel/Storage/StorageDevice.cpp
+	kernel/Syscall.cpp
+	kernel/Syscall.S
+	kernel/Terminal/Serial.cpp
+	kernel/Terminal/TTY.cpp
+	kernel/Terminal/VesaTerminalDriver.cpp
+	kernel/Terminal/VirtualTTY.cpp
+	kernel/Thread.cpp
+	kernel/Timer/HPET.cpp
+	kernel/Timer/PIT.cpp
+	kernel/Timer/RTC.cpp
+	kernel/Timer/Timer.cpp
+	icxxabi.cpp
+)
+
+#set(ENABLE_KERNEL_UBSAN True)
+
+if(ENABLE_KERNEL_UBSAN)
+	set(KERNEL_SOURCES ${KERNEL_SOURCES} ubsan.cpp)
+endif()
+
+if("${BANAN_ARCH}" STREQUAL "x86_64")
+	set(KERNEL_SOURCES
+		${KERNEL_SOURCES}
+		arch/x86_64/boot.S
+		arch/x86_64/GDT.cpp
+		arch/x86_64/IDT.cpp
+		arch/x86_64/interrupts.S
+		arch/x86_64/PageTable.cpp
+		arch/x86_64/Signal.S
+		arch/x86_64/Thread.S
+	)
+elseif("${BANAN_ARCH}" STREQUAL "i386")
+	set(KERNEL_SOURCES
+		${KERNEL_SOURCES}
+		arch/i386/boot.S
+		arch/i386/GDT.cpp
+		arch/i386/IDT.cpp
+		arch/i386/MMU.cpp
+		arch/i386/SpinLock.S
+		arch/i386/Thread.S
+	)
+else()
+	message(FATAL_ERROR "unsupported architecure ${BANAN_ARCH}")
+endif()
+
+file(GLOB_RECURSE LAI_SOURCES
+	lai/*.c
+)
+set(LAI_SOURCES
+	${LAI_SOURCES}
+	kernel/lai_host.cpp
+)
+
+set(BAN_SOURCES
+	../BAN/BAN/New.cpp
+	../BAN/BAN/String.cpp
+	../BAN/BAN/StringView.cpp
+	../BAN/BAN/Time.cpp
+)
+
+set(LIBC_SOURCES
+	../libc/ctype.cpp
+	../libc/string.cpp
+)
+
+set(LIBELF_SOURCES
+	../LibELF/LibELF/LoadableELF.cpp
+)
+
+set(KERNEL_SOURCES
+	${KERNEL_SOURCES}
+	${LAI_SOURCES}
+	${BAN_SOURCES}
+	${LIBC_SOURCES}
+	${LIBELF_SOURCES}
+)
+
+add_executable(kernel ${KERNEL_SOURCES})
+add_dependencies(kernel headers)
+
+target_compile_definitions(kernel PUBLIC __is_kernel)
+target_compile_definitions(kernel PUBLIC __arch=${BANAN_ARCH})
+
+target_compile_options(kernel PUBLIC -O2 -g)
+target_compile_options(kernel PUBLIC $<$<COMPILE_LANGUAGE:CXX>:-Wno-literal-suffix -fno-rtti -fno-exceptions>)
+target_compile_options(kernel PUBLIC -fmacro-prefix-map=${CMAKE_CURRENT_SOURCE_DIR}=.)
+target_compile_options(kernel PUBLIC -fstack-protector -ffreestanding -Wall -Werror=return-type -Wstack-usage=1024 -fno-omit-frame-pointer -mgeneral-regs-only)
+
+# This might not work with other toolchains
+target_compile_options(kernel PUBLIC $<$<COMPILE_LANGUAGE:CXX>:-Wno-invalid-offsetof>)
+
+if(ENABLE_KERNEL_UBSAN)
+	target_compile_options(kernel PUBLIC -fsanitize=undefined)
+endif()
+
+if("${BANAN_ARCH}" STREQUAL "x86_64")
+	target_compile_options(kernel PUBLIC -mcmodel=kernel -mno-red-zone -mno-mmx)
+	target_link_options(kernel PUBLIC LINKER:-z,max-page-size=4096)
+	target_link_options(kernel PUBLIC LINKER:-T,${CMAKE_CURRENT_SOURCE_DIR}/arch/x86_64/linker.ld)
+elseif("${BANAN_ARCH}" STREQUAL "i386")
+	target_link_options(kernel PUBLIC LINKER:-T,${CMAKE_CURRENT_SOURCE_DIR}/arch/i386/linker.ld)
+endif()
+
+target_link_options(kernel PUBLIC -ffreestanding -nostdlib)
+
+add_custom_target(kernel-headers
+	COMMAND ${CMAKE_COMMAND} -E copy_directory_if_different ${CMAKE_CURRENT_SOURCE_DIR}/include/ ${BANAN_INCLUDE}/
+	COMMAND ${CMAKE_COMMAND} -E copy_directory_if_different ${CMAKE_CURRENT_SOURCE_DIR}/lai/include/ ${BANAN_INCLUDE}/
+	DEPENDS sysroot
+)
+
+add_custom_target(kernel-install
+	COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/kernel ${BANAN_BOOT}/banan-os.kernel
+	DEPENDS kernel
+)
+
+execute_process(COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=crtbegin.o OUTPUT_VARIABLE CRTBEGIN OUTPUT_STRIP_TRAILING_WHITESPACE)
+execute_process(COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=crtend.o OUTPUT_VARIABLE CRTEND OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+add_custom_command(
+	TARGET kernel PRE_LINK
+	COMMAND ${CMAKE_CXX_COMPILER} -MD -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crti.S ${COMPILE_OPTIONS}
+	COMMAND ${CMAKE_CXX_COMPILER} -MD -c ${CMAKE_CURRENT_SOURCE_DIR}/arch/${BANAN_ARCH}/crtn.S ${COMPILE_OPTIONS}
+	COMMAND ${CMAKE_COMMAND} -E copy ${CRTBEGIN} .
+	COMMAND ${CMAKE_COMMAND} -E copy ${CRTEND} .
+)
+
+#add_custom_command(
+#	TARGET kernel POST_BUILD
+#	COMMAND x86_64-banan_os-strip ${CMAKE_CURRENT_BINARY_DIR}/kernel
+#)
+
+add_custom_command(
+	OUTPUT font/prefs.psf.o
+	COMMAND cd ${CMAKE_CURRENT_SOURCE_DIR} && objcopy -O ${ELF_FORMAT} -B i386 -I binary font/prefs.psf ${CMAKE_CURRENT_BINARY_DIR}/font/prefs.psf.o
+)
+
+set(CMAKE_CXX_LINK_EXECUTABLE "${CMAKE_CXX_COMPILER} <CMAKE_CXX_LINK_FLAGS> <FLAGS> <LINK_FLAGS> -o <TARGET> ${CMAKE_CURRENT_BINARY_DIR}/crti.o ${CMAKE_CURRENT_BINARY_DIR}/crtbegin.o <OBJECTS> ${CMAKE_CURRENT_BINARY_DIR}/crtend.o ${CMAKE_CURRENT_BINARY_DIR}/crtn.o -lgcc ")

kernel/Makefile

@@ -1,131 +0,0 @@
-DEFAULT_HOST!=../default-host.sh
-HOST?=DEFAULT_HOST
-HOSTARCH!=../target-triplet-to-arch.sh $(HOST)
- 
-CFLAGS?=-O2 -g
-CPPFLAGS?=
-LDFLAGS?=
-LIBS?=
- 
-DESTDIR?=
-PREFIX?=/usr/local
-EXEC_PREFIX?=$(PREFIX)
-BOOTDIR?=$(EXEC_PREFIX)/boot
-INCLUDEDIR?=$(PREFIX)/include
- 
-CFLAGS:=$(CFLAGS) -D__is_kernel -D__arch=$(HOSTARCH) -Iinclude -fstack-protector -ffreestanding -Wall -Wextra -Werror=return-type -fno-omit-frame-pointer -mno-sse -mno-sse2
-CPPFLAGS:=$(CPPFLAGS) -fno-rtti -fno-exceptions
-LDFLAGS:=$(LDFLAGS)
-LIBS:=$(LIBS) -nostdlib -lk -lbank -lgcc
- 
-ARCHDIR=arch/$(HOSTARCH)
- 
-include $(ARCHDIR)/make.config
- 
-CFLAGS:=$(CFLAGS) $(KERNEL_ARCH_CFLAGS)
-CPPFLAGS:=$(CPPFLAGS) $(KERNEL_ARCH_CPPFLAGS)
-LDFLAGS:=$(LDFLAGS) $(KERNEL_ARCH_LDFLAGS)
-LIBS:=$(LIBS) $(KERNEL_ARCH_LIBS)
- 
-ifeq ($(UBSAN), 1)
-CFLAGS:=$(CFLAGS) -fsanitize=undefined
-endif
- 
-BUILDDIR=$(abspath build)
- 
-KERNEL_OBJS=					\
-$(KERNEL_ARCH_OBJS)				\
-font/prefs.o					\
-kernel/APIC.o					\
-kernel/build_libc.o				\
-kernel/CPUID.o					\
-kernel/Debug.o					\
-kernel/Font.o					\
-kernel/FS/Ext2.o				\
-kernel/FS/VirtualFileSystem.o	\
-kernel/Input.o					\
-kernel/InterruptController.o	\
-kernel/kernel.o					\
-kernel/kmalloc.o				\
-kernel/PCI.o					\
-kernel/PIC.o					\
-kernel/PIT.o					\
-kernel/Process.o				\
-kernel/RTC.o					\
-kernel/Scheduler.o				\
-kernel/Serial.o					\
-kernel/Shell.o					\
-kernel/SpinLock.o				\
-kernel/SSP.o					\
-kernel/Storage/ATAController.o	\
-kernel/Storage/StorageDevice.o	\
-kernel/Syscall.o				\
-kernel/Thread.o					\
-kernel/TTY.o					\
-kernel/VesaTerminalDriver.o		\
-userspace/userspace.o			\
-icxxabi.o						\
-ubsan.o							\
- 
-OBJS=					\
-$(ARCHDIR)/crti.o		\
-$(ARCHDIR)/crtbegin.o	\
-$(KERNEL_OBJS)			\
-$(ARCHDIR)/crtend.o		\
-$(ARCHDIR)/crtn.o		\
- 
-LINK_LIST=				\
-$(LDFLAGS)				\
-$(ARCHDIR)/crti.o		\
-$(ARCHDIR)/crtbegin.o	\
-$(KERNEL_OBJS)			\
-$(LIBS)					\
-$(ARCHDIR)/crtend.o		\
-$(ARCHDIR)/crtn.o		\
- 
-.PHONY: all always clean install install-headers install-kernel
-.SUFFIXES: .o .c .cpp .S .psf
- 
-all: banan-os.kernel
- 
-banan-os.kernel: always $(OBJS) $(ARCHDIR)/linker.ld
-	cd $(BUILDDIR) && $(CXX) -T ../$(ARCHDIR)/linker.ld -o banan-os.kernel $(CFLAGS) $(CPPFLAGS) $(LINK_LIST)
-	cd $(BUILDDIR) && grub-file --is-x86-multiboot banan-os.kernel
- 
-$(ARCHDIR)/crtbegin.o $(ARCHDIR)/crtend.o:
-	OBJ=`$(CC) $(CFLAGS) $(LDFLAGS) -print-file-name=$(@F)` && cp "$$OBJ" $(BUILDDIR)/$@
- 
-.c.o:
-	$(CC) -MD -c $< -o $(BUILDDIR)/$@ $(CFLAGS)
- 
-.cpp.o:
-	$(CXX) -MD -c $< -o $(BUILDDIR)/$@ $(CFLAGS) $(CPPFLAGS)
- 
-.S.o:
-	$(CC) -MD -c $< -o $(BUILDDIR)/$@ $(CFLAGS)
- 
-.psf.o:
-	objcopy -O $(ELF_FORMAT) -B i386 -I binary $< $(BUILDDIR)/$@
-
-always:
-	mkdir -p $(BUILDDIR)/$(ARCHDIR)
-	mkdir -p $(BUILDDIR)/kernel
-	mkdir -p $(BUILDDIR)/kernel/FS
-	mkdir -p $(BUILDDIR)/kernel/Storage
-	mkdir -p $(BUILDDIR)/userspace
-	mkdir -p $(BUILDDIR)/font
-
-clean:
-	rm -rf $(BUILDDIR)
-
-install: install-headers install-kernel
- 
-install-headers:
-	mkdir -p $(DESTDIR)$(INCLUDEDIR)
-	cp -R --preserve=timestamps include/. $(DESTDIR)$(INCLUDEDIR)/.
- 
-install-kernel: banan-os.kernel
-	mkdir -p $(DESTDIR)$(BOOTDIR)
-	cp $(BUILDDIR)/banan-os.kernel $(DESTDIR)$(BOOTDIR)
- 
--include $(OBJS:.o=.d)

kernel/arch/i386/GDT.cpp

@@ -109,6 +109,11 @@ namespace Kernel::GDT
 		write_entry(offset, (uint32_t)s_tss, sizeof(TaskStateSegment), 0x89, 0x0);
 	}
 
+	void set_tss_stack(uintptr_t esp)
+	{
+		s_tss->esp0 = esp;
+	}
+
 	static void flush_gdt()
 	{
 		asm volatile("lgdt %0" :: "m"(s_gdtr));

kernel/arch/i386/IDT.cpp

@@ -1,8 +1,9 @@
 #include <BAN/Errors.h>
 #include <kernel/IDT.h>
 #include <kernel/InterruptController.h>
-#include <kernel/kmalloc.h>
+#include <kernel/Memory/kmalloc.h>
 #include <kernel/Panic.h>
+#include <kernel/Scheduler.h>
 
 #define INTERRUPT_HANDLER____(i, msg)													\
 	static void interrupt ## i ()														\
@@ -132,6 +133,8 @@ found:
 		// NOTE: Scheduler sends PIT eoi's
 		if (irq != PIT_IRQ)
 			InterruptController::get().eoi(irq);
+
+		Kernel::Scheduler::get().reschedule_if_idling();
 	}
 
 	extern "C" void handle_irq_common();
@@ -171,7 +174,18 @@ found:
 		"addl $16, %esp;"
 		"popw %es;"
 		"popw %ds;"
-		"popa;"
+		
+		// NOTE: following instructions are same as in 'popa', except we skip eax
+		//       since it holds the return value of the syscall.
+		"popl %edi;"
+		"popl %esi;"
+		"popl %ebp;"
+		"addl $4, %esp;"
+		"popl %ebx;"
+		"popl %edx;"
+		"popl %ecx;"
+		"addl $4, %esp;"
+		
 		"iret;"
 	);
 

kernel/arch/i386/MMU.cpp

@@ -1,136 +1,227 @@
 #include <BAN/Errors.h>
 #include <kernel/Debug.h>
-#include <kernel/MMU.h>
-#include <kernel/kmalloc.h>
+#include <kernel/Memory/MMU.h>
+#include <kernel/Memory/kmalloc.h>
 
 #include <string.h>
 
 #define MMU_DEBUG_PRINT 0
 
 // bits 31-12 set
-#define PAGE_MASK 0xfffff000
-#define PAGE_SIZE 0x00001000
+#define PAGE_MASK  0xfffff000
+#define FLAGS_MASK 0x00000fff
 
-static MMU* s_instance = nullptr;
-
-void MMU::intialize()
+namespace Kernel
 {
-	ASSERT(s_instance == nullptr);
-	s_instance = new MMU();
-}
 
-MMU& MMU::get()
-{
-	ASSERT(s_instance);
-	return *s_instance;
-}
+	static MMU* s_instance = nullptr;
 
-static uint64_t* allocate_page_aligned_page()
-{
-	uint64_t* page = (uint64_t*)kmalloc(PAGE_SIZE, PAGE_SIZE);
-	ASSERT(page);
-	ASSERT(((uintptr_t)page % PAGE_SIZE) == 0);
-	memset(page, 0, PAGE_SIZE);
-	return page;
-}
-
-MMU::MMU()
-{
-	m_highest_paging_struct = (uint64_t*)kmalloc(sizeof(uint64_t) * 4, 32);
-	ASSERT(m_highest_paging_struct);
-	ASSERT(((uintptr_t)m_highest_paging_struct % 32) == 0);
-
-	// allocate all page directories
-	for (int i = 0; i < 4; i++)
+	void MMU::initialize()
 	{
-		uint64_t* page_directory = allocate_page_aligned_page();
-		m_highest_paging_struct[i] = (uint64_t)page_directory | Flags::Present;
+		ASSERT(s_instance == nullptr);
+		s_instance = new MMU();
+		ASSERT(s_instance);
+		s_instance->initialize_kernel();
+		s_instance->load();
 	}
 
-	// create and identity map first 6 MiB
-	uint64_t* page_directory1 = (uint64_t*)(m_highest_paging_struct[0] & PAGE_MASK);
-	for (uint64_t i = 0; i < 3; i++)
+	MMU& MMU::get()
 	{
-		uint64_t* page_table = allocate_page_aligned_page();
-		for (uint64_t j = 0; j < 512; j++)
-			page_table[j] = (i << 21) | (j << 12) | Flags::ReadWrite | Flags::Present;
-
-		page_directory1[i] = (uint64_t)page_table | Flags::ReadWrite | Flags::Present;
+		ASSERT(s_instance);
+		return *s_instance;
 	}
 
-	// dont map first page (0 -> 4 KiB) so that nullptr dereference
-	// causes page fault :)
-	uint64_t* page_table1 = (uint64_t*)(page_directory1[0] & PAGE_MASK);
-	page_table1[0] = 0;
-
-	// reload this new pdpt
-	asm volatile("movl %0, %%cr3" :: "r"(m_highest_paging_struct));
-}
-
-void MMU::allocate_page(uintptr_t address, uint8_t flags)
-{
-#if MMU_DEBUG_PRINT
-	dprintln("AllocatePage(0x{8H})", address);
-#endif
-	ASSERT(flags & Flags::Present);
-
-	address &= PAGE_MASK;
-
-	uint32_t pdpte = (address & 0xC0000000) >> 30;
-	uint32_t pde   = (address & 0x3FE00000) >> 21;
-	uint32_t pte   = (address & 0x001FF000) >> 12;
-
-	uint64_t* page_directory = (uint64_t*)(m_highest_paging_struct[pdpte] & PAGE_MASK);
-	if (!(page_directory[pde] & Flags::Present))
+	static uint64_t* allocate_page_aligned_page()
 	{
-		uint64_t* page_table = allocate_page_aligned_page();
-		page_directory[pde] = (uint64_t)page_table;
+		uint64_t* page = (uint64_t*)kmalloc(PAGE_SIZE, PAGE_SIZE);
+		ASSERT(page);
+		ASSERT(((uintptr_t)page % PAGE_SIZE) == 0);
+		memset(page, 0, PAGE_SIZE);
+		return page;
 	}
-	page_directory[pde] |= flags;
 
-	uint64_t* page_table = (uint64_t*)(page_directory[pde] & PAGE_MASK);
-	page_table[pte] = address | flags;
+	void MMU::initialize_kernel()
+	{
+		m_highest_paging_struct = (uint64_t*)kmalloc(sizeof(uint64_t) * 4, 32);
+		ASSERT(m_highest_paging_struct);
+		ASSERT(((uintptr_t)m_highest_paging_struct % 32) == 0);
+
+		// allocate all page directories
+		for (int i = 0; i < 4; i++)
+		{
+			uint64_t* page_directory = allocate_page_aligned_page();
+			m_highest_paging_struct[i] = (uint64_t)page_directory | Flags::Present;
+		}
+
+		// FIXME: We should just identity map until g_kernel_end
+
+		// create and identity map first 6 MiB
+		uint64_t* page_directory1 = (uint64_t*)(m_highest_paging_struct[0] & PAGE_MASK);
+		for (uint64_t i = 0; i < 3; i++)
+		{
+			uint64_t* page_table = allocate_page_aligned_page();
+			for (uint64_t j = 0; j < 512; j++)
+				page_table[j] = (i << 21) | (j << 12) | Flags::ReadWrite | Flags::Present;
+
+			page_directory1[i] = (uint64_t)page_table | Flags::ReadWrite | Flags::Present;
+		}
+
+		// dont map first page (0 -> 4 KiB) so that nullptr dereference
+		// causes page fault :)
+		uint64_t* page_table1 = (uint64_t*)(page_directory1[0] & PAGE_MASK);
+		page_table1[0] = 0;
+	}
+
+	MMU::MMU()
+	{
+		if (s_instance == nullptr)
+			return;
+		
+		// Here we copy the s_instances paging structs since they are
+		// global for every process
+
+		uint64_t* global_pdpt = s_instance->m_highest_paging_struct;
+
+		uint64_t* pdpt = (uint64_t*)kmalloc(sizeof(uint64_t) * 4, 32);
+		ASSERT(pdpt);
+		
+		for (uint32_t pdpte = 0; pdpte < 4; pdpte++)
+		{
+			if (!(global_pdpt[pdpte] & Flags::Present))
+				continue;
+
+			uint64_t* global_pd = (uint64_t*)(global_pdpt[pdpte] & PAGE_MASK);
+
+			uint64_t* pd = allocate_page_aligned_page();
+			pdpt[pdpte] = (uint64_t)pd | (global_pdpt[pdpte] & ~PAGE_MASK);
+
+			for (uint32_t pde = 0; pde < 512; pde++)
+			{
+				if (!(global_pd[pde] & Flags::Present))
+					continue;
+
+				uint64_t* global_pt = (uint64_t*)(global_pd[pde] & PAGE_MASK);
+
+				uint64_t* pt = allocate_page_aligned_page();
+				pd[pde] = (uint64_t)pt | (global_pd[pde] & ~PAGE_MASK);
+
+				memcpy(pt, global_pt, PAGE_SIZE);
+			}
+		}
+
+		m_highest_paging_struct = pdpt;
+	}
+
+	MMU::~MMU()
+	{
+		uint64_t* pdpt = m_highest_paging_struct;
+		for (uint32_t pdpte = 0; pdpte < 512; pdpte++)
+		{
+			if (!(pdpt[pdpte] & Flags::Present))
+				continue;
+			uint64_t* pd = (uint64_t*)(pdpt[pdpte] & PAGE_MASK);
+			for (uint32_t pde = 0; pde < 512; pde++)
+			{
+				if (!(pd[pde] & Flags::Present))
+					continue;
+				kfree((void*)(pd[pde] & PAGE_MASK));
+			}
+			kfree(pd);
+		}
+		kfree(pdpt);
+	}
+
+	void MMU::load()
+	{
+		asm volatile("movl %0, %%cr3" :: "r"(m_highest_paging_struct));
+	}
+
+	void MMU::map_page_at(paddr_t paddr, vaddr_t vaddr, uint8_t flags)
+	{
+	#if MMU_DEBUG_PRINT
+		dprintln("AllocatePage(0x{8H})", address);
+	#endif
+		ASSERT(flags & Flags::Present);
+
+		ASSERT(!(paddr & ~PAGE_MASK));
+		ASSERT(!(vaddr & ~PAGE_MASK));
+
+		uint32_t pdpte = (vaddr & 0xC0000000) >> 30;
+		uint32_t pde   = (vaddr & 0x3FE00000) >> 21;
+		uint32_t pte   = (vaddr & 0x001FF000) >> 12;
+
+		uint64_t* page_directory = (uint64_t*)(m_highest_paging_struct[pdpte] & PAGE_MASK);
+		if (!(page_directory[pde] & Flags::Present))
+		{
+			uint64_t* page_table = allocate_page_aligned_page();
+			page_directory[pde] = (uint64_t)page_table;
+		}
+		page_directory[pde] |= flags;
+
+		uint64_t* page_table = (uint64_t*)(page_directory[pde] & PAGE_MASK);
+		page_table[pte] = paddr | flags;
+	}
+
+	void MMU::identity_map_page(paddr_t address, uint8_t flags)
+	{
+		address &= PAGE_MASK;
+		map_page_at(address, address, flags);
+	}
+
+	void MMU::identity_map_range(paddr_t address, ptrdiff_t size, uint8_t flags)
+	{
+		paddr_t s_page = address & PAGE_MASK;
+		paddr_t e_page = (address + size - 1) & PAGE_MASK;
+		for (paddr_t page = s_page; page <= e_page; page += PAGE_SIZE)
+			identity_map_page(page, flags);
+	}
+
+	void MMU::unmap_page(vaddr_t address)
+	{
+	#if MMU_DEBUG_PRINT
+		dprintln("UnAllocatePage(0x{8H})", address & PAGE_MASK);
+	#endif
+
+		uint32_t pdpte = (address & 0xC0000000) >> 30;
+		uint32_t pde   = (address & 0x3FE00000) >> 21;
+		uint32_t pte   = (address & 0x001FF000) >> 12;
+
+		uint64_t* page_directory = (uint64_t*)(m_highest_paging_struct[pdpte] & PAGE_MASK);
+		if (!(page_directory[pde] & Flags::Present))
+			return;
+
+		uint64_t* page_table = (uint64_t*)(page_directory[pde] & PAGE_MASK);
+		if (!(page_table[pte] & Flags::Present))
+			return;
+
+		page_table[pte] = 0;
+
+		// TODO: Unallocate the page table if this was the only allocated page
+	}
+
+	void MMU::unmap_range(vaddr_t address, ptrdiff_t size)
+	{
+		uintptr_t s_page = address & PAGE_MASK;
+		uintptr_t e_page = (address + size - 1) & PAGE_MASK;
+		for (uintptr_t page = s_page; page <= e_page; page += PAGE_SIZE)
+			unmap_page(page);
+	}
+
+	uint8_t MMU::get_page_flags(vaddr_t address) const
+	{
+		uint32_t pdpte = (address & 0xC0000000) >> 30;
+		uint32_t pde   = (address & 0x3FE00000) >> 21;
+		uint32_t pte   = (address & 0x001FF000) >> 12;
+
+		uint64_t* page_directory = (uint64_t*)(m_highest_paging_struct[pdpte] & PAGE_MASK);
+		if (!(page_directory[pde] & Flags::Present))
+			return 0;
+
+		uint64_t* page_table = (uint64_t*)(page_directory[pde] & PAGE_MASK);
+		if (!(page_table[pte] & Flags::Present))
+			return 0;
+
+		return page_table[pte] & FLAGS_MASK;
+	}
 
-	asm volatile("invlpg (%0)" :: "r"(address) : "memory");
-}
-
-void MMU::allocate_range(uintptr_t address, ptrdiff_t size, uint8_t flags)
-{
-	uintptr_t s_page = address & PAGE_MASK;
-	uintptr_t e_page = (address + size - 1) & PAGE_MASK;
-	for (uintptr_t page = s_page; page <= e_page; page += PAGE_SIZE)
-		allocate_page(page, flags);
-}
-
-void MMU::unallocate_page(uintptr_t address)
-{
-#if MMU_DEBUG_PRINT
-	dprintln("UnAllocatePage(0x{8H})", address & PAGE_MASK);
-#endif
-
-	uint32_t pdpte = (address & 0xC0000000) >> 30;
-	uint32_t pde   = (address & 0x3FE00000) >> 21;
-	uint32_t pte   = (address & 0x001FF000) >> 12;
-
-	uint64_t* page_directory = (uint64_t*)(m_highest_paging_struct[pdpte] & PAGE_MASK);
-	if (!(page_directory[pde] & Flags::Present))
-		return;
-
-	uint64_t* page_table = (uint64_t*)(page_directory[pde] & PAGE_MASK);
-	if (!(page_table[pte] & Flags::Present))
-		return;
-
-	page_table[pte] = 0;
-
-	// TODO: Unallocate the page table if this was the only allocated page
-
-	asm volatile("invlpg (%0)" :: "r"(address & PAGE_MASK) : "memory");
-}
-
-void MMU::unallocate_range(uintptr_t address, ptrdiff_t size)
-{
-	uintptr_t s_page = address & PAGE_MASK;
-	uintptr_t e_page = (address + size - 1) & PAGE_MASK;
-	for (uintptr_t page = s_page; page <= e_page; page += PAGE_SIZE)
-		unallocate_page(page);
 }

kernel/arch/i386/Thread.S

@@ -26,3 +26,22 @@ continue_thread:
 	movl 4(%esp), %esp
 	movl $0, %eax
 	jmp *%ecx
+
+# void thread_jump_userspace(uint32_t rsp, uint32_t rip)
+.global thread_jump_userspace
+thread_jump_userspace:
+	movl $0x23, %eax
+	movw %ax, %ds
+	movw %ax, %es
+	movw %ax, %fs
+	movw %ax, %gs
+
+	movl 8(%esp), %ecx
+	movl 4(%esp), %esp
+
+	pushl $0x23
+	pushl %esp
+	pushfl
+	pushl $0x1B
+	pushl %ecx
+	iret

kernel/arch/i386/boot.S

@@ -28,9 +28,7 @@ g_boot_stack_bottom:
 g_boot_stack_top:
 
 # 0 MiB -> 1 MiB: bootloader stuff
-# 1 MiB -> 2 MiB: kernel
-# 2 MiB -> 3 MiB: kmalloc
-# 3 MiB -> 4 Mib: kmalloc_fixed
+# 1 MiB ->      : kernel
 .align 32
 boot_page_directory_pointer_table:
 	.skip 4 * 8

kernel/arch/i386/crt0.S

@@ -0,0 +1,23 @@
+.section .text
+
+.global _start
+_start:
+	# Set up end of the stack frame linked list.
+	movl $0, %ebp
+	pushl %ebp # rip=0
+	pushl %ebp # rbp=0
+	movl %esp, %ebp
+
+	# Prepare signals, memory allocation, stdio and such.
+	#call initialize_standard_library
+
+	# Run the global constructors.
+	call _init
+
+	# Run main
+	call main
+
+	# Terminate the process with the exit code.
+	movl %eax, %edi
+	call exit
+.size _start, . - _start

kernel/arch/i386/linker.ld

@@ -4,6 +4,7 @@ SECTIONS
 {
 	. = 0x00100000;
 
+	g_kernel_start = .;
 	.text BLOCK(4K) : ALIGN(4K)
 	{
 		*(.multiboot)
@@ -11,9 +12,7 @@ SECTIONS
 	}
 	.rodata BLOCK(4K) : ALIGN(4K)
 	{
-		g_rodata_start = .;
 		*(.rodata.*)
-		g_rodata_end = .;
 	}
 	.data BLOCK(4K) : ALIGN(4K)
 	{
@@ -26,13 +25,4 @@ SECTIONS
 	}
 
 	g_kernel_end = .;
-
-	. = 0x00A00000;
-
-	g_userspace_start = .;
-	.userspace BLOCK(4K) : ALIGN(4K)
-	{
-		*(.userspace)
-	}
-	g_userspace_end = .;
 }

kernel/arch/i386/make.config

@@ -1,15 +0,0 @@
-KERNEL_ARCH_CFLAGS=
-KERNEL_ARCH_CPPFLAGS=
-KERNEL_ARCH_LDFLAGS=
-KERNEL_ARCH_LIBS=
- 
-ELF_FORMAT=elf32-i386
-
-KERNEL_ARCH_OBJS=		\
-$(ARCHDIR)/boot.o		\
-$(ARCHDIR)/GDT.o		\
-$(ARCHDIR)/IDT.o		\
-$(ARCHDIR)/MMU.o		\
-$(ARCHDIR)/SpinLock.o	\
-$(ARCHDIR)/Thread.o		\
-