Kernel: Rework filesystem reading

We now read from a filesystem to user provided buffer.

Read sizes are determined by read call.

You should now get file descriptors and do reading through Process::current()

kernel/include/kernel/FS/Ext2.h

@@ -131,12 +131,13 @@ namespace Kernel
 
 		virtual BAN::StringView name() const override { return m_name; }
 
-		virtual BAN::ErrorOr<BAN::Vector<uint8_t>> read_all() override;
+		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override;
 		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes() override;
 		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView) override;
 
 	private:
-		BAN::ErrorOr<void> for_each_block(BAN::Function<BAN::ErrorOr<bool>(const BAN::Vector<uint8_t>&)>&);
+		using block_callback_t = BAN::ErrorOr<bool>(*)(const BAN::Vector<uint8_t>&, void*);
+		BAN::ErrorOr<void> for_each_block(block_callback_t, void*);
 
 	private:
 		Ext2Inode() {}

kernel/include/kernel/FS/Inode.h

@@ -36,6 +36,8 @@ namespace Kernel
 		};
 
 	public:
+		virtual ~Inode() {}
+
 		bool ifdir() const { return mode().IFDIR; }
 		bool ifreg() const { return mode().IFREG; }
 
@@ -47,7 +49,7 @@ namespace Kernel
 
 		virtual BAN::StringView name() const = 0;
 
-		virtual BAN::ErrorOr<BAN::Vector<uint8_t>> read_all() = 0;
+		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) = 0;
 		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes() = 0;
 		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView) = 0;
 	};

kernel/include/kernel/FS/VirtualFileSystem.h

@@ -15,19 +15,22 @@ namespace Kernel
 		static VirtualFileSystem& get();
 		virtual ~VirtualFileSystem() {};
 
-		virtual const BAN::RefPtr<Inode> root_inode() const override;
+		virtual const BAN::RefPtr<Inode> root_inode() const override  { return m_root_inode; }
 
-		void close_inode(BAN::StringView);
+		struct File
-
+		{
-		BAN::ErrorOr<BAN::RefPtr<Inode>> from_absolute_path(BAN::StringView);
+			BAN::RefPtr<Inode> inode;
+			BAN::String canonical_path;
+		};
+		BAN::ErrorOr<File> file_from_absolute_path(BAN::StringView);
 
 	private:
 		VirtualFileSystem() = default;
 		BAN::ErrorOr<void> initialize_impl();
 
 	private:
-		BAN::HashMap<BAN::String, BAN::RefPtr<Inode>>	m_open_inodes;
+		BAN::RefPtr<Inode>				m_root_inode;
-		BAN::Vector<StorageController*>					m_storage_controllers;
+		BAN::Vector<StorageController*>	m_storage_controllers;
 	};
 
 }

kernel/include/kernel/Process.h

@@ -1,7 +1,9 @@
 #pragma once
 
 #include <BAN/String.h>
+#include <BAN/StringView.h>
 #include <BAN/Vector.h>
+#include <kernel/FS/Inode.h>
 #include <kernel/Thread.h>
 
 namespace Kernel
@@ -24,12 +26,39 @@ namespace Kernel
 
 		pid_t pid() const { return m_pid; }
 
+		BAN::ErrorOr<int> open(BAN::StringView, int);
+		BAN::ErrorOr<void> close(int);
+		BAN::ErrorOr<size_t> read(int, void*, size_t);
+
+		BAN::StringView working_directory() const { return m_working_directory; }
+		BAN::ErrorOr<void> set_working_directory(BAN::StringView);
+
+		Inode& inode_for_fd(int);
+
 		static BAN::RefPtr<Process> current() { return Thread::current()->process(); }
 
 	private:
 		Process(pid_t pid) : m_pid(pid) {}
 
+		BAN::ErrorOr<BAN::String> absolute_path_of(BAN::StringView) const;
+
 	private:
+		struct OpenFileDescription
+		{
+			BAN::RefPtr<Inode> inode;
+			BAN::String path;
+			size_t offset = 0;
+			uint8_t flags = 0;
+
+			BAN::ErrorOr<size_t> read(void*, size_t);
+		};
+
+		BAN::ErrorOr<void> validate_fd(int);
+		OpenFileDescription& open_file_description(int);
+		BAN::ErrorOr<int> get_free_fd();
+
+		BAN::Vector<OpenFileDescription> m_open_files;
+
 		pid_t m_pid = 0;
 		BAN::String m_working_directory;
 		BAN::Vector<BAN::RefPtr<Thread>> m_threads;

kernel/include/kernel/Shell.h

@@ -13,7 +13,7 @@ namespace Kernel
 	public:
 		Shell(TTY*);
 		Shell(const Shell&) = delete;
-		void set_prompt(BAN::StringView);
+		BAN::ErrorOr<void> set_prompt(BAN::StringView);
 		void run();
 
 	private:
@@ -21,11 +21,13 @@ namespace Kernel
 		BAN::Vector<BAN::String> parse_arguments(BAN::StringView) const;
 		BAN::ErrorOr<void> process_command(const BAN::Vector<BAN::String>&);
 		void key_event_callback(Input::KeyEvent);
+		BAN::ErrorOr<void> update_prompt();
 
 	private:
 		TTY*						m_tty;
 		BAN::Vector<BAN::String>	m_old_buffer;
 		BAN::Vector<BAN::String>	m_buffer;
+		BAN::String					m_prompt_string;
 		BAN::String					m_prompt;
 		uint32_t					m_prompt_length = 0;
 		

kernel/kernel/FS/Ext2.cpp

@@ -138,7 +138,7 @@ namespace Kernel
 
 	}
 	
-	BAN::ErrorOr<void> Ext2Inode::for_each_block(BAN::Function<BAN::ErrorOr<bool>(const BAN::Vector<uint8_t>&)>& func)
+	BAN::ErrorOr<void> Ext2Inode::for_each_block(block_callback_t callback, void* callback_data)
 	{
 		uint32_t data_blocks_left = m_inode.blocks / (2 << m_fs->superblock().log_block_size);
 		uint32_t block_array_block_count = (1024 << m_fs->superblock().log_block_size) / sizeof(uint32_t);
@@ -150,7 +150,7 @@ namespace Kernel
 				continue;
 
 			auto block_data = TRY(m_fs->read_block(m_inode.block[i]));
-			if (!TRY(func(block_data)))
+			if (!TRY(callback(block_data, callback_data)))
 				return {};
 			if (--data_blocks_left == 0)
 				return {};
@@ -166,7 +166,7 @@ namespace Kernel
 				if (block == 0)
 					continue;
 				auto block_data = TRY(m_fs->read_block(block));
-				if (!TRY(func(block_data)))
+				if (!TRY(callback(block_data, callback_data)))
 					return {};
 				if (--data_blocks_left == 0)
 					return {};
@@ -187,7 +187,7 @@ namespace Kernel
 					if (block == 0)
 						continue;
 					auto block_data = TRY(m_fs->read_block(block));
-					if (!TRY(func(block_data)))
+					if (!TRY(callback(block_data, callback_data)))
 						return {};
 					if (--data_blocks_left == 0)
 						return {};
@@ -213,7 +213,7 @@ namespace Kernel
 						if (block == 0)
 							continue;
 						auto block_data = TRY(m_fs->read_block(block));
-						if (!TRY(func(block_data)))
+						if (!TRY(callback(block_data, callback_data)))
 							return {};
 						if (--data_blocks_left == 0)
 							return {};
@@ -225,32 +225,63 @@ namespace Kernel
 		return BAN::Error::from_c_string("Inode did not contain enough blocks");
 	}
 
-	BAN::ErrorOr<BAN::Vector<uint8_t>> Ext2Inode::read_all()
+	BAN::ErrorOr<size_t> Ext2Inode::read(size_t offset, void* buffer, size_t count)
 	{
 		if (ifdir())
 			return BAN::Error::from_errno(EISDIR);
 
-		BAN::Vector<uint8_t> data_buffer;
+		struct read_info
-		TRY(data_buffer.resize(m_inode.size));
+		{
+			size_t file_current_offset;
+			size_t file_start_offset;
+			size_t file_bytes_left;
+			uint8_t* out_byte_buffer;
+			size_t out_bytes_read;
+			size_t out_byte_buffer_size;
+		};
 
-		uint32_t bytes_done = 0;
+		read_info info;
-		uint32_t bytes_left = m_inode.size;
+		info.file_current_offset	= 0;
+		info.file_start_offset		= offset;
+		info.file_bytes_left		= m_inode.size;
+		info.out_byte_buffer		= (uint8_t*)buffer;
+		info.out_bytes_read			= 0;
+		info.out_byte_buffer_size	= count;
 
-		BAN::Function<BAN::ErrorOr<bool>(const BAN::Vector<uint8_t>&)> read_func(
+		block_callback_t read_func = 
-			[&](const BAN::Vector<uint8_t>& block_data)
+			[](const BAN::Vector<uint8_t>& block_data, void* info_) -> BAN::ErrorOr<bool>
 			{
-				uint32_t to_copy = BAN::Math::min<uint32_t>(block_data.size(), bytes_left);
+				read_info& info = *(read_info*)info_;
-				memcpy(data_buffer.data() + bytes_done, block_data.data(), to_copy);
-				bytes_done += to_copy;
-				bytes_left -= to_copy;
-				return bytes_left > 0;
-			}
-		);
 
-		TRY(for_each_block(read_func));
+				size_t block_size = BAN::Math::min<size_t>(block_data.size(), info.file_bytes_left);
-		ASSERT(bytes_left == 0);
 
-		return data_buffer;
+				// Skip blocks before 'offset'
+				if (info.file_current_offset + block_size <= info.file_start_offset)
+				{
+					info.file_current_offset += block_size;
+					info.file_bytes_left -= block_size;
+					return info.file_bytes_left > 0;
+				}
+
+				size_t read_offset = 0;
+				if (info.file_current_offset < info.file_start_offset)
+					read_offset = info.file_start_offset - info.file_current_offset;
+
+				size_t to_read = BAN::Math::min<size_t>(block_size - read_offset, info.out_byte_buffer_size - info.out_bytes_read);
+				memcpy(info.out_byte_buffer + info.out_bytes_read, block_data.data() + read_offset, to_read);
+
+				info.out_bytes_read += to_read;
+				if (info.out_bytes_read >= info.out_byte_buffer_size)
+					return false;
+
+				info.file_current_offset += block_size;
+				info.file_bytes_left -= block_size;
+				return info.file_bytes_left > 0;
+			};
+
+		TRY(for_each_block(read_func, &info));
+
+		return info.out_bytes_read;
 	}
 
 	BAN::ErrorOr<BAN::RefPtr<Inode>> Ext2Inode::directory_find(BAN::StringView file_name)
@@ -258,33 +289,45 @@ namespace Kernel
 		if (!ifdir())
 			return BAN::Error::from_errno(ENOTDIR);
 
-		BAN::RefPtr<Inode> result;
+		struct search_info
-		BAN::Function<BAN::ErrorOr<bool>(const BAN::Vector<uint8_t>&)> function(
+		{
-			[&](const BAN::Vector<uint8_t>& block_data) -> BAN::ErrorOr<bool>
+			BAN::StringView file_name;
+			BAN::RefPtr<Inode> result;
+			Ext2FS* fs;
+		};
+
+		search_info info;
+		info.file_name = file_name;
+		info.result = {};
+		info.fs = m_fs;
+
+		block_callback_t function =
+			[](const BAN::Vector<uint8_t>& block_data, void* info_) -> BAN::ErrorOr<bool>
 			{
+				search_info& info = *(search_info*)info_;
+
 				uintptr_t block_data_end = (uintptr_t)block_data.data() + block_data.size();
 				uintptr_t entry_addr = (uintptr_t)block_data.data();
 				while (entry_addr < block_data_end)
 				{
 					Ext2::LinkedDirectoryEntry* entry = (Ext2::LinkedDirectoryEntry*)entry_addr;
 					BAN::StringView entry_name = BAN::StringView(entry->name, entry->name_len);
-					if (entry->inode && file_name == entry_name)
+					if (entry->inode && info.file_name == entry_name)
 					{
-						Ext2Inode* inode = new Ext2Inode(m_fs, TRY(m_fs->read_inode(entry->inode)), entry_name);
+						Ext2Inode* inode = new Ext2Inode(info.fs, TRY(info.fs->read_inode(entry->inode)), entry_name);
 						if (inode == nullptr)
 							return BAN::Error::from_errno(ENOMEM);
-						result = BAN::RefPtr<Inode>::adopt(inode);
+						info.result = BAN::RefPtr<Inode>::adopt(inode);
 						return false;
 					}
 					entry_addr += entry->rec_len;
 				}
 				return true;
-			}
+			};
-		);
 
-		TRY(for_each_block(function));
+		TRY(for_each_block(function, &info));
-		if (result)
+		if (info.result)
-			return result;
+			return info.result;
 		return BAN::Error::from_errno(ENOENT);
 	}
 
@@ -293,10 +336,21 @@ namespace Kernel
 		if (!ifdir())
 			return BAN::Error::from_errno(ENOTDIR);
 
-		BAN::Vector<BAN::RefPtr<Inode>> inodes;
+		struct directory_info
-		BAN::Function<BAN::ErrorOr<bool>(const BAN::Vector<uint8_t>&)> function(
+		{
-			[&](const BAN::Vector<uint8_t>& block_data) -> BAN::ErrorOr<bool>
+			BAN::Vector<BAN::RefPtr<Inode>> inodes;
+			Ext2FS* fs;
+		};
+
+		directory_info info;
+		info.inodes = {};
+		info.fs = m_fs;
+
+		block_callback_t function =
+			[](const BAN::Vector<uint8_t>& block_data, void* info_) -> BAN::ErrorOr<bool>
 			{
+				directory_info& info = *(directory_info*)info_;
+
 				uintptr_t block_data_end = (uintptr_t)block_data.data() + block_data.size();
 				uintptr_t entry_addr = (uintptr_t)block_data.data();
 				while (entry_addr < block_data_end)
@@ -305,22 +359,21 @@ namespace Kernel
 					if (entry->inode)
 					{
 						BAN::StringView entry_name = BAN::StringView(entry->name, entry->name_len);
-						Ext2::Inode current_inode = TRY(m_fs->read_inode(entry->inode));
+						Ext2::Inode current_inode = TRY(info.fs->read_inode(entry->inode));
 
-						Ext2Inode* inode = new Ext2Inode(m_fs, BAN::move(current_inode), entry_name);
+						Ext2Inode* inode = new Ext2Inode(info.fs, BAN::move(current_inode), entry_name);
 						if (inode == nullptr)
 							return BAN::Error::from_errno(ENOMEM);
-						TRY(inodes.push_back(BAN::RefPtr<Inode>::adopt(inode)));
+						TRY(info.inodes.push_back(BAN::RefPtr<Inode>::adopt(inode)));
 					}
 					entry_addr += entry->rec_len;
 				}
 				return true;
-			}
+			};
-		);
 
-		TRY(for_each_block(function));
+		TRY(for_each_block(function, &info));
 
-		return inodes;
+		return info.inodes;
 	}
 
 	BAN::ErrorOr<Ext2FS*> Ext2FS::create(StorageDevice::Partition& partition)

kernel/kernel/FS/VirtualFileSystem.cpp

@@ -103,7 +103,7 @@ namespace Kernel
 							else
 								// FIXME: We leave a dangling pointer to ext2fs. This might be okay since
 								//        root fs sould probably be always mounted
-								TRY(m_open_inodes.insert("/"sv, ext2fs_or_error.release_value()->root_inode()));
+								m_root_inode = ext2fs_or_error.value()->root_inode();
 						}
 					}
 				}
@@ -115,40 +115,52 @@ namespace Kernel
 		return {};
 	}
 
-	const BAN::RefPtr<Inode> VirtualFileSystem::root_inode() const
+	BAN::ErrorOr<VirtualFileSystem::File> VirtualFileSystem::file_from_absolute_path(BAN::StringView path)
-	{
-		if (!m_open_inodes.contains("/"sv))
-			return nullptr;
-		return m_open_inodes["/"sv];
-	}
-
-	void VirtualFileSystem::close_inode(BAN::StringView path)
-	{
-		ASSERT(m_open_inodes.contains(path));
-
-		// Delete the cached inode, if we are the only one holding a reference to it
-		if (m_open_inodes[path]->ref_count() == 1)
-			m_open_inodes.remove(path);
-	}
-
-	BAN::ErrorOr<BAN::RefPtr<Inode>> VirtualFileSystem::from_absolute_path(BAN::StringView path)
 	{
 		ASSERT(path.front() == '/');
-		
-		if (m_open_inodes.contains(path))
-			return m_open_inodes[path];
 
 		auto inode = root_inode();
 		if (!inode)
 			return BAN::Error::from_c_string("No root inode available");
 
 		auto path_parts = TRY(path.split('/'));
-		for (BAN::StringView part : path_parts)
-			inode = TRY(inode->directory_find(part));
-		
-		TRY(m_open_inodes.insert(path, inode));
 
-		return inode;
+		for (size_t i = 0; i < path_parts.size();)
+		{
+			if (path_parts[i] == "."sv)
+			{
+				path_parts.remove(i);
+			}
+			else if (path_parts[i] == ".."sv)
+			{
+				inode = TRY(inode->directory_find(path_parts[i]));
+				path_parts.remove(i);
+				if (i > 0)
+				{
+					path_parts.remove(i - 1);
+					i--;
+				}
+			}
+			else
+			{
+				inode = TRY(inode->directory_find(path_parts[i]));
+				i++;
+			}
+		}
+
+		File file;
+		file.inode = inode;
+
+		for (const auto& part : path_parts)
+		{
+			TRY(file.canonical_path.push_back('/'));
+			TRY(file.canonical_path.append(part));
+		}
+
+		if (file.canonical_path.empty())
+			TRY(file.canonical_path.push_back('/'));
+
+		return file;
 	}
 
 }

kernel/kernel/Font.cpp

@@ -1,6 +1,9 @@
 #include <BAN/UTF8.h>
+#include <BAN/ScopeGuard.h>
 #include <kernel/Font.h>
-#include <kernel/FS/VirtualFileSystem.h>
+#include <kernel/Process.h>
+
+#include <fcntl.h>
 
 #define PSF1_MODE_512			0x01
 #define PSF1_MODE_HASTAB		0x02
@@ -25,9 +28,13 @@ namespace Kernel
 
 	BAN::ErrorOr<Font> Font::load(BAN::StringView path)
 	{
-		auto inode = TRY(VirtualFileSystem::get().from_absolute_path(path));
+		int fd = TRY(Process::current()->open(path, O_RDONLY));
+		BAN::ScopeGuard _([fd] { MUST(Process::current()->close(fd)); });
 
-		auto file_data = TRY(inode->read_all());
+		size_t file_size = Process::current()->inode_for_fd(fd).size();
+		BAN::Vector<uint8_t> file_data;
+		TRY(file_data.resize(file_size));
+		TRY(Process::current()->read(fd, file_data.data(), file_size));
 
 		if (file_data.size() < 4)
 			return BAN::Error::from_c_string("Font file is too small");

kernel/kernel/Process.cpp

@@ -1,6 +1,9 @@
 #include <BAN/StringView.h>
 #include <kernel/Process.h>
 #include <kernel/Scheduler.h>
+#include <kernel/FS/VirtualFileSystem.h>
+
+#include <fcntl.h>
 
 namespace Kernel
 {
@@ -9,8 +12,8 @@ namespace Kernel
 	{
 		static pid_t next_pid = 1;
 		auto process = TRY(BAN::RefPtr<Process>::create(next_pid++));
+		TRY(process->m_working_directory.push_back('/'));
 		TRY(process->add_thread(entry, data));
-		TRY(process->m_working_directory.append("/"sv));
 		return process;
 	}
 
@@ -24,14 +27,112 @@ namespace Kernel
 			return res;
 		}
 
-		dprintln("add thread {} to process {}", thread->tid(), pid());
-
 		return {};
 	}
 
 	void Process::on_thread_exit(Thread& thread)
 	{
-		dprintln("thread {} exited from process", thread.tid(), pid());
+		(void)thread;
+	}
+
+	BAN::ErrorOr<int> Process::open(BAN::StringView path, int flags)
+	{
+		if (flags != O_RDONLY)
+			return BAN::Error::from_errno(ENOTSUP);
+
+		BAN::String absolute_path = TRY(absolute_path_of(path));
+
+		auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(absolute_path));
+
+		int fd = TRY(get_free_fd());
+		auto& open_file_description = m_open_files[fd];
+		open_file_description.inode = file.inode;
+		open_file_description.path = BAN::move(file.canonical_path);
+		open_file_description.offset = 0;
+		open_file_description.flags = flags;
+
+		return fd;
+	}
+
+	BAN::ErrorOr<void> Process::close(int fd)
+	{
+		TRY(validate_fd(fd));
+		auto& open_file_description = this->open_file_description(fd);
+		open_file_description.inode = nullptr;
+		return {};
+	}
+
+	BAN::ErrorOr<size_t> Process::read(int fd, void* buffer, size_t count)
+	{
+		TRY(validate_fd(fd));
+		auto& open_file_description = this->open_file_description(fd);
+		if (open_file_description.offset >= open_file_description.inode->size())
+			return 0;
+		size_t n_read = TRY(open_file_description.read(buffer, count));
+		return n_read;
+	}
+
+	Inode& Process::inode_for_fd(int fd)
+	{
+		MUST(validate_fd(fd));
+		return *open_file_description(fd).inode;
+	}
+
+	BAN::ErrorOr<void> Process::set_working_directory(BAN::StringView path)
+	{
+		BAN::String absolute_path = TRY(absolute_path_of(path));
+
+		auto file = TRY(VirtualFileSystem::get().file_from_absolute_path(absolute_path));
+		if (!file.inode->ifdir())
+			return BAN::Error::from_errno(ENOTDIR);
+
+		m_working_directory = BAN::move(file.canonical_path);
+
+		return {};
+	}
+
+	BAN::ErrorOr<BAN::String> Process::absolute_path_of(BAN::StringView path) const
+	{
+		if (path.empty())
+			return m_working_directory;
+		BAN::String absolute_path;
+		if (path.front() != '/')
+		{
+			TRY(absolute_path.append(m_working_directory));
+			if (m_working_directory.sv().back() != '/')
+				TRY(absolute_path.push_back('/'));
+		}
+		TRY(absolute_path.append(path));
+		return absolute_path;
+	}
+
+	BAN::ErrorOr<size_t> Process::OpenFileDescription::read(void* buffer, size_t count)
+	{
+		size_t n_read = TRY(inode->read(offset, buffer, count));
+		offset += n_read;
+		return n_read;
+	}
+
+	BAN::ErrorOr<void> Process::validate_fd(int fd)
+	{
+		if (fd < 0 || m_open_files.size() <= (size_t)fd || !m_open_files[fd].inode)
+			return BAN::Error::from_errno(EBADF);
+		return {};
+	}
+
+	Process::OpenFileDescription& Process::open_file_description(int fd)
+	{
+		MUST(validate_fd(fd));
+		return m_open_files[fd];
+	}
+
+	BAN::ErrorOr<int> Process::get_free_fd()
+	{
+		for (size_t fd = 0; fd < m_open_files.size(); fd++)
+			if (!m_open_files[fd].inode)
+				return fd;
+		TRY(m_open_files.push_back({}));
+		return m_open_files.size() - 1;
 	}
 
 }

kernel/kernel/Shell.cpp

@@ -1,16 +1,17 @@
 #include <BAN/Math.h>
+#include <BAN/ScopeGuard.h>
 #include <BAN/StringView.h>
 #include <BAN/Vector.h>
 #include <kernel/CPUID.h>
 #include <kernel/Input.h>
 #include <kernel/IO.h>
 #include <kernel/PIT.h>
+#include <kernel/PCI.h>
 #include <kernel/Process.h>
 #include <kernel/RTC.h>
 #include <kernel/Shell.h>
 
-#include <kernel/FS/VirtualFileSystem.h>
+#include <fcntl.h>
-
 #include <ctype.h>
 
 #define TTY_PRINT(...) Formatter::print([this](char c) { m_tty->putchar(c); }, __VA_ARGS__)
@@ -20,38 +21,62 @@ namespace Kernel
 {
 	using namespace BAN;
 
-	static auto s_default_prompt = "\\[\e[32m\\]user\\[\e[m\\]# "sv;
+	static auto s_default_prompt = "\\[\e[32m\\]user\\[\e[m\\]:\\[\e[34m\\]\\w\\[\e[m\\]# "sv;
 
 	Shell::Shell(TTY* tty)
 		: m_tty(tty)
 	{
 		Input::register_key_event_callback({ &Shell::key_event_callback, this });
-		set_prompt(s_default_prompt);
+		MUST(set_prompt(s_default_prompt));
 		MUST(m_buffer.push_back(""sv));
 	}
 
-	void Shell::set_prompt(StringView prompt)
+	BAN::ErrorOr<void> Shell::set_prompt(StringView prompt)
+	{
+		m_prompt_string = prompt;
+		TRY(update_prompt());
+		return {};
+	}
+
+	BAN::ErrorOr<void> Shell::update_prompt()
 	{
 		m_prompt_length = 0;
 		m_prompt = String();
 
 		bool skipping = false;
-		for (size_t i = 0; i < prompt.size(); i++)
+		for (size_t i = 0; i < m_prompt_string.size(); i++)
 		{
-			if (i < prompt.size() - 1 && prompt[i] == '\\')
+			if (i < m_prompt_string.size() - 1 && m_prompt_string[i] == '\\')
 			{
-				if (prompt[i + 1] == '[')
+				switch (m_prompt_string[i + 1])
-					skipping = true;
+				{
-				if (prompt[i + 1] == ']')
+					case '[':
-					skipping = false;
+						skipping = true;
+						break;
+					case ']':
+						skipping = false;
+						break;
+					case 'w':
+					{
+						auto working_directory = Process::current()->working_directory();
+						TRY(m_prompt.append(working_directory));
+						m_prompt_length += working_directory.size();
+						break;
+					}
+					default:
+						dprintln("unknown escape character '{}' in shell prompt", m_prompt_string[i + 1]);
+						break;
+				}
 				i++;
 				continue;
 			}
 			
-			MUST(m_prompt.push_back(prompt[i]));
+			TRY(m_prompt.push_back(m_prompt_string[i]));
 			if (!skipping)
 				m_prompt_length++;
 		}
+
+		return {};
 	}
 
 	void Shell::run()
@@ -276,12 +301,13 @@ argument_done:
 			if (arguments.size() > 2)
 				return BAN::Error::from_c_string("usage: 'ls [path]'");
 
-			BAN::StringView path = (arguments.size() == 2) ? arguments[1].sv() : "/";
+			BAN::StringView path = (arguments.size() == 2) ? arguments[1].sv() : Process::current()->working_directory();
-			if (path.front() != '/')
-				return BAN::Error::from_c_string("ls currently works only with absolute paths");
 
-			auto directory = TRY(VirtualFileSystem::get().from_absolute_path(path));
+			int fd = TRY(Process::current()->open(path, O_RDONLY));
-			auto inodes = TRY(directory->directory_inodes());
+			BAN::ScopeGuard _([fd] { MUST(Process::current()->close(fd)); });
+
+			auto& directory = Process::current()->inode_for_fd(fd);
+			auto inodes = TRY(directory.directory_inodes());
 
 			auto mode_string = [](Inode::Mode mode)
 			{
@@ -299,7 +325,6 @@ argument_done:
 				return (const char*)buffer;
 			};
 
-			TTY_PRINTLN("{}", path);
 			for (auto& inode : inodes)
 				if (inode->ifdir())
 					TTY_PRINTLN("  {} {7} \e[34m{}\e[m", mode_string(inode->mode()), inode->size(), inode->name());
@@ -312,9 +337,26 @@ argument_done:
 			if (arguments.size() != 2)
 				return BAN::Error::from_c_string("usage: 'cat path'");
 			
-			auto file = TRY(VirtualFileSystem::get().from_absolute_path(arguments[1]));
+			int fd = TRY(Process::current()->open(arguments[1], O_RDONLY));
-			auto data = TRY(file->read_all());
+			BAN::ScopeGuard _([fd] { MUST(Process::current()->close(fd)); });
-			TTY_PRINTLN("{}", BAN::StringView((const char*)data.data(), data.size()));
+
+			char buffer[1024] {};
+			while (true)
+			{
+				size_t n_read = TRY(Process::current()->read(fd, buffer, sizeof(buffer)));
+				if (n_read == 0)
+					break;
+				TTY_PRINT("{}", BAN::StringView(buffer, n_read));
+			}
+			TTY_PRINTLN("");
+		}
+		else if (arguments.front() == "cd")
+		{
+			if (arguments.size() > 2)
+				return BAN::Error::from_c_string("usage 'cd path'");
+			BAN::StringView path = arguments.size() == 2 ? arguments[1].sv() : "/"sv;
+			TRY(Process::current()->set_working_directory(path));
+			TRY(update_prompt());
 		}
 		else if (arguments.front() == "loadfont")
 		{

kernel/kernel/kernel.cpp

@@ -196,12 +196,6 @@ void init2(void* tty1_ptr)
 
 	MUST(VirtualFileSystem::initialize());
 
-	auto font_or_error = Font::load("/usr/share/fonts/zap-ext-vga16.psf");
-	if (font_or_error.is_error())
-		dprintln("{}", font_or_error.error());
-	else
-		tty1->set_font(font_or_error.release_value());
-
 	MUST(Process::create_kernel(
 		[](void* tty1) 
 		{