ls: Write group name instead of gid in list mode

BAN/BAN/StringView.cpp

@@ -61,7 +61,7 @@ namespace BAN
 		return result;
 	}
 
-	ErrorOr<Vector<StringView>> StringView::split(char delim, bool allow_empties)
+	ErrorOr<Vector<StringView>> StringView::split(char delim, bool allow_empties) const
 	{
 		size_type count = 0;
 		{
@@ -92,12 +92,12 @@ namespace BAN
 				start = i + 1;
 			}
 		}
-		if (start != m_size)
+		if (start < m_size || (start == m_size && allow_empties))
 			TRY(result.push_back(this->substring(start)));
 		return result;
 	}
 
-	ErrorOr<Vector<StringView>> StringView::split(bool(*comp)(char), bool allow_empties)
+	ErrorOr<Vector<StringView>> StringView::split(bool(*comp)(char), bool allow_empties) const
 	{
 		size_type count = 0;
 		{
@@ -128,7 +128,7 @@ namespace BAN
 				start = i + 1;
 			}
 		}
-		if (start != m_size)
+		if (start < m_size || (start == m_size && allow_empties))
 			TRY(result.push_back(this->substring(start)));
 		return result;
 	}

BAN/include/BAN/StringView.h

@@ -30,8 +30,8 @@ namespace BAN
 
 		StringView substring(size_type, size_type = -1) const;
 
-		ErrorOr<Vector<StringView>> split(char, bool = false);
-		ErrorOr<Vector<StringView>> split(bool(*comp)(char), bool = false);
+		ErrorOr<Vector<StringView>> split(char, bool = false) const;
+		ErrorOr<Vector<StringView>> split(bool(*comp)(char), bool = false) const;
 
 		char back() const;
 		char front() const;

libc/CMakeLists.txt

@@ -7,6 +7,7 @@ set(LIBC_SOURCES
 	ctype.cpp
 	dirent.cpp
 	fcntl.cpp
+	grp.cpp
 	malloc.cpp
 	printf_impl.cpp
 	pwd.cpp

libc/grp.cpp

@@ -0,0 +1,162 @@
+#include <BAN/StringView.h>
+#include <BAN/Vector.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+
+static struct stat s_group_st;
+static char* s_group_mmap = nullptr;
+static int s_group_fd = -1;
+
+static struct group s_group;
+
+id_t parse_id(BAN::StringView string)
+{
+	id_t id = 0;
+	for (char c : string)
+	{
+		if (!isdigit(c))
+			return -1;
+		id = (id * 10) + (c - '0');
+	}
+	return id;
+}
+
+static bool open_group_file()
+{
+	if (s_group_fd == -1)
+		s_group_fd = open("/etc/group", O_RDONLY);
+	if (s_group_fd == -1)
+		return false;
+
+	if (fstat(s_group_fd, &s_group_st) == -1)
+		return false;
+
+	if (s_group_mmap == nullptr || s_group_mmap == MAP_FAILED)
+		s_group_mmap = (char*)mmap(nullptr, s_group_st.st_size, PROT_READ, MAP_PRIVATE, s_group_fd, 0);
+	if (s_group_mmap == MAP_FAILED)
+		return false;
+
+	s_group.gr_name = nullptr;
+	s_group.gr_mem = nullptr;
+
+	return true;
+}
+
+struct group* fill_group(const BAN::Vector<BAN::StringView>& parts)
+{
+	if (parts.size() != 4)
+		return nullptr;
+
+	if (s_group.gr_name)
+	{
+		free(s_group.gr_name);
+		s_group.gr_name = nullptr;
+	}
+
+	if (s_group.gr_mem)
+	{
+		for (size_t i = 0; s_group.gr_mem && s_group.gr_mem[i]; i++)
+			free(s_group.gr_mem[i]);
+		free(s_group.gr_mem);
+		s_group.gr_mem = nullptr;
+	}
+
+	auto groups_or_error = parts[3].split(',');	
+	if (groups_or_error.is_error())
+		return nullptr;
+	auto groups = groups_or_error.release_value();
+
+	s_group.gr_gid = parse_id(parts[2]);
+	if (s_group.gr_gid == -1)
+		return nullptr;
+
+	s_group.gr_name = (char*)malloc(parts[0].size() + 1);
+	if (s_group.gr_name == nullptr)
+		return nullptr;
+	memcpy(s_group.gr_name, parts[0].data(), parts[0].size());	
+	s_group.gr_name[parts[0].size()] = '\0';
+
+	s_group.gr_mem = (char**)malloc((groups.size() + 1) * sizeof(char*));
+	if (s_group.gr_mem == nullptr)
+		return nullptr;
+
+	for (size_t i = 0; i < groups.size(); i++)
+	{
+		s_group.gr_mem[i] = (char*)malloc(groups[i].size() + 1);
+		if (s_group.gr_mem[i] == nullptr)
+		{
+			for (size_t j = 0; j < i; j++)
+				free(s_group.gr_mem[j]);
+			free(s_group.gr_mem);
+			s_group.gr_mem = nullptr;
+			return nullptr;
+		}
+		memcpy(s_group.gr_mem[i], groups[i].data(), groups[i].size());
+		s_group.gr_mem[i][groups[i].size()] = '\0';
+	}	
+	s_group.gr_mem[groups.size()] = nullptr;
+
+	return &s_group;
+}
+
+struct group* getgrnam(const char* name)
+{
+	if (s_group_mmap == nullptr || s_group_mmap == MAP_FAILED)
+		if (!open_group_file())
+			return nullptr;
+	
+	off_t start = 0;
+	off_t end = 0;
+	while (start < s_group_st.st_size)
+	{
+		while (end < s_group_st.st_size && s_group_mmap[end] != '\n')
+			end++;
+
+		BAN::StringView line(s_group_mmap + start, end - start);
+		start = ++end;
+
+		auto parts_or_error = line.split(':', true);
+		if (parts_or_error.is_error())
+			return nullptr;
+
+		auto parts = parts_or_error.release_value();
+		if (parts.size() == 4 && parts[0] == name)
+			return fill_group(parts);
+	}
+
+	return nullptr;
+}
+
+struct group* getgrgid(gid_t gid)
+{
+	if (s_group_mmap == nullptr || s_group_mmap == MAP_FAILED)
+		if (!open_group_file())
+			return nullptr;
+	
+	off_t start = 0;
+	off_t end = 0;
+	while (start < s_group_st.st_size)
+	{
+		while (end < s_group_st.st_size && s_group_mmap[end] != '\n')
+			end++;
+
+		BAN::StringView line(s_group_mmap + start, end - start);
+		start = ++end;
+
+		auto parts_or_error = line.split(':', true);
+		if (parts_or_error.is_error())
+			return nullptr;
+
+		auto parts = parts_or_error.release_value();
+		if (parts.size() == 4 && parse_id(parts[2]) == gid)
+			return fill_group(parts);
+	}
+
+	return nullptr;
+}

userspace/ls/main.cpp

@@ -5,6 +5,7 @@
 
 #include <dirent.h>
 #include <fcntl.h>
+#include <grp.h>
 #include <pwd.h>
 #include <stdio.h>
 #include <sys/stat.h>
@@ -84,7 +85,10 @@ BAN::String build_owner_name_string(uid_t uid)
 
 BAN::String build_owner_group_string(gid_t gid)
 {
+	struct group* grp = getgrgid(gid);
+	if (grp == nullptr)
 		return BAN::String::formatted("{}", gid);
+	return BAN::String(BAN::StringView(grp->gr_name));
 }
 
 BAN::String build_size_string(off_t size)