Kernel/LibC: Add SYS_TRUNCATE

kernel/include/kernel/OpenFileDescriptorSet.h

@@ -36,6 +36,8 @@ namespace Kernel
 		BAN::ErrorOr<off_t> seek(int fd, off_t offset, int whence);
 		BAN::ErrorOr<off_t> tell(int) const;
 
+		BAN::ErrorOr<void> truncate(int fd, off_t length);
+
 		BAN::ErrorOr<void> fstat(int fd, struct stat*) const;
 		BAN::ErrorOr<void> fstatat(int fd, BAN::StringView path, struct stat* buf, int flag);
 		BAN::ErrorOr<void> stat(BAN::StringView absolute_path, struct stat* buf, int flag);

kernel/include/kernel/Process.h

@@ -138,6 +138,8 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_seek(int fd, off_t offset, int whence);
 		BAN::ErrorOr<long> sys_tell(int fd);
 
+		BAN::ErrorOr<long> sys_truncate(int fd, off_t length);
+
 		BAN::ErrorOr<long> sys_fstat(int fd, struct stat*);
 		BAN::ErrorOr<long> sys_fstatat(int fd, const char* path, struct stat* buf, int flag);
 		BAN::ErrorOr<long> sys_stat(const char* path, struct stat* buf, int flag);

kernel/kernel/OpenFileDescriptorSet.cpp

@@ -242,6 +242,12 @@ namespace Kernel
 		return m_open_files[fd]->offset;
 	}
 
+	BAN::ErrorOr<void> OpenFileDescriptorSet::truncate(int fd, off_t length)
+	{
+		TRY(validate_fd(fd));
+		return m_open_files[fd]->inode->truncate(length);
+	}
+
 	static void read_stat_from_inode(BAN::RefPtr<Inode> inode, struct stat* out)
 	{
 		out->st_dev		= inode->dev();

kernel/kernel/Process.cpp

@@ -1145,6 +1145,13 @@ namespace Kernel
 		return TRY(m_open_file_descriptors.tell(fd));
 	}
 
+	BAN::ErrorOr<long> Process::sys_truncate(int fd, off_t length)
+	{
+		LockGuard _(m_process_lock);
+		TRY(m_open_file_descriptors.truncate(fd, length));
+		return 0;
+	}
+
 	BAN::ErrorOr<void> Process::mount(BAN::StringView source, BAN::StringView target)
 	{
 		BAN::String absolute_source, absolute_target;

libc/include/sys/syscall.h

@@ -73,6 +73,7 @@ __BEGIN_DECLS
 	O(SYS_CONNECT,			connect)		\
 	O(SYS_LISTEN,			listen)			\
 	O(SYS_PSELECT,			pselect)		\
+	O(SYS_TRUNCATE,			truncate)		\
 
 enum Syscall
 {

libc/unistd.cpp

@@ -99,6 +99,11 @@ off_t lseek(int fildes, off_t offset, int whence)
 	return syscall(SYS_SEEK, fildes, offset, whence);
 }
 
+int ftruncate(int fildes, off_t length)
+{
+	return syscall(SYS_TRUNCATE, fildes, length);
+}
+
 int dup(int fildes)
 {
 	return syscall(SYS_DUP, fildes);