The Virtual File System (VFS) is an abstraction layer that allows the kernel to interact with different filesystems in a uniform way. More...

Collaboration diagram for Virtual File System:

Topics
	Directory Entry
	Directory entry.

Functions
should_inline const file_ops_t *	file_get_ops (file_t *file)

file_t *	vfs_do_open_dentry (dentry_t *entry, bool created, bool read, bool write, bool exec, bool truncate)
	Open an directory dentry.

void	vfs_register_filesystem (filesystem_t *fs)

long	vfs_mount (const char device, const char path, const char fs, const char options)
	Mount a filesystem at a given existing path.

long	vfs_unmount (const char *path)
	Unmount a filesystem at a given path.

file_t *	vfs_openat (int fd, const char *path, open_flags flags)
	Open a file at a given path.

long	vfs_fstatat (fd_t fd, const char path, file_stat_t restrict stat, fstatat_flags flags)
	Stat a file.

size_t	vfs_readlinkat (fd_t dirfd, const char path, char buf, size_t size)
	Read a symbolic link.

long	vfs_symlink (const char path, const char target)
	Create a symbolic link.

long	vfs_mkdir (const char *path)
	Create a directory.

long	vfs_rmdir (const char *path)

size_t	vfs_list_dir (io_t io, void buf, size_t size)
	Get the content of a directory.

long	vfs_chdirat (fd_t dirfd, const char *path)
	Change the current working directory.

ssize_t	vfs_getcwd (char *buf, size_t size)
	Get the current working directory.

long	vfs_fchmodat (fd_t fd, const char *path, int perm, int flags)
	Change the permissions of a file.

long	vfs_unlinkat (fd_t dirfd, const char *path)
	Remove the name of a file, and possibly the file itself.

long	vfs_fsync (io_t *io, bool sync_metadata, off_t start, off_t end)
	Synchronize a file with the filesystem.

Variables
dentry_t *	root_dentry

Detailed Description

The Virtual File System (VFS) is an abstraction layer that allows the kernel to interact with different filesystems in a uniform way.

Function Documentation

◆ file_get_ops()

should_inline const file_ops_t * file_get_ops ( file_t * file )

Definition at line 18 of file vfs.h.

Referenced by vfs_do_open_dentry(), vfs_io_ops_close(), vfs_io_ops_mmap(), vfs_io_ops_munmap(), vfs_io_ops_read(), vfs_io_ops_seek(), and vfs_io_ops_write().

◆ vfs_do_open_dentry()

file_t * vfs_do_open_dentry	(	dentry_t *	entry,
		bool	created,
		bool	read,
		bool	write,
		bool	exec,
		bool	truncate )

Open an directory dentry.

Parameters

entry
created
read
write
exec
truncate

Returns: file_t

Definition at line 413 of file vfs.c.

Referenced by memfd_create(), and vfs_do_open().

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◆ vfs_register_filesystem()

void vfs_register_filesystem ( filesystem_t * fs )

Definition at line 452 of file vfs.c.

Referenced by MOS_INIT(), and userfs_manager_register_filesystem().

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◆ vfs_mount()

long vfs_mount	(	const char *	device,
		const char *	path,
		const char *	fs,
		const char *	options )

Mount a filesystem at a given existing path.

Parameters

device	The device to mount
path	The path to mount the filesystem at, this absolute path to a directory must exist
fs	The filesystem type, e.g. "tmpfs"
options	The options to pass to the filesystem

Returns: true if the filesystem was mounted successfully; false if the filesystem could not be mounted, see the kernel log for more information

Definition at line 466 of file vfs.c.

Referenced by mos_start_kernel(), MOS_STATIC_ASSERT(), and MOS_TEST_DECL_PTEST().

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◆ vfs_unmount()

long vfs_unmount ( const char * path )

Unmount a filesystem at a given path.

Parameters

path	The path to the filesystem

Returns: true; false

Definition at line 536 of file vfs.c.

Referenced by MOS_STATIC_ASSERT(), and MOS_TEST_DECL_PTEST().

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◆ vfs_openat()

file_t * vfs_openat	(	int	fd,
		const char *	path,
		open_flags	flags )

Open a file at a given path.

Parameters

fd	The fd of an open directory, or AT_FDCWD to use the current working directory
path	The path to the file, can be absolute or relative
flags	open_flags flags

Returns: file_t* The file, or NULL if the file could not be opened

Definition at line 578 of file vfs.c.

Referenced by elf_create_process(), elf_map_interpreter(), and process_do_execveat().

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◆ vfs_fstatat()

long vfs_fstatat	(	fd_t	fd,
		const char *	path,
		file_stat_t *restrict	stat,
		fstatat_flags	flags )

Stat a file.

Parameters

fd	The directory, or a file if FSTATAT_FILE is set
path	The path to the file
flags	fstat_flags flags
stat	The stat struct to store the file information in

If the FSTATAT_FILE is set, the fd is a file, and the path will be ignored. If it is not set: If the path is absolute, the fd will be ignored. If the path is relative, the fd will be used as the directory to resolve the path from. If FSTATAT_NOFOLLOW is set, when the path is used, symlinks will not be followed.

Definition at line 588 of file vfs.c.

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◆ vfs_readlinkat()

size_t vfs_readlinkat	(	fd_t	dirfd,
		const char *	path,
		char *	buf,
		size_t	size )

Read a symbolic link.

Parameters

dirfd	The file descriptor of the directory containing the symbolic link
path	The path to the symbolic link
buf	The buffer to store the link in
size	The size of the buffer

Returns: size_t The size of the link, or 0 if the link could not be read, or the buffer was too small

Definition at line 623 of file vfs.c.

Referenced by MOS_STATIC_ASSERT().

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◆ vfs_symlink()

long vfs_symlink	(	const char *	path,
		const char *	target )

Create a symbolic link.

Parameters

path	The path to the symbolic link
target	The target of the symbolic link

Returns: true; false

Definition at line 646 of file vfs.c.

Referenced by MOS_STATIC_ASSERT().

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◆ vfs_mkdir()

long vfs_mkdir ( const char * path )

Create a directory.

Parameters

path	The path to the directory

Returns: true; false

Definition at line 664 of file vfs.c.

Referenced by mos_start_kernel(), MOS_STATIC_ASSERT(), and MOS_TEST_DECL_PTEST().

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◆ vfs_rmdir()

long vfs_rmdir ( const char * path )

Definition at line 689 of file vfs.c.

Referenced by MOS_TEST_DECL_PTEST().

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◆ vfs_list_dir()

size_t vfs_list_dir	(	io_t *	io,
		void *	buf,
		size_t	size )

Get the content of a directory.

Parameters

io	The io object of a file_t, must be a directory and opened with FILE_OPEN_READ
buf	The buffer to store the directory entries in
size	The size of the buffer

Returns: size_t The number of bytes read, or 0 if the end of the directory was reached

Definition at line 713 of file vfs.c.

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◆ vfs_chdirat()

long vfs_chdirat	(	fd_t	dirfd,
		const char *	path )

Change the current working directory.

Parameters

dirfd	The file descriptor of the directory to change to
path	The path to the directory, relative to the dirfd

Returns: long 0 on success, or errno on failure

Definition at line 764 of file vfs.c.

Referenced by MOS_STATIC_ASSERT().

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◆ vfs_getcwd()

ssize_t vfs_getcwd	(	char *	buf,
		size_t	size )

Get the current working directory.

Parameters

buf	The buffer to store the path in
size	The size of the buffer

Returns: ssize_t The size of the path, or 0 if the buffer was too small

Definition at line 780 of file vfs.c.

Referenced by MOS_STATIC_ASSERT().

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◆ vfs_fchmodat()

long vfs_fchmodat	(	fd_t	fd,
		const char *	path,
		int	perm,
		int	flags )

Change the permissions of a file.

Parameters

fd	The directory, or a file if FSTATAT_FILE is set
path	The path to the file
perm	The new permissions
flags	fstat_flags flags

Returns: long 0 on success, or errno on failure

Definition at line 789 of file vfs.c.

Referenced by MOS_STATIC_ASSERT().

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◆ vfs_unlinkat()

long vfs_unlinkat	(	fd_t	dirfd,
		const char *	path )

Remove the name of a file, and possibly the file itself.

Parameters

dirfd	The file descriptor of the directory containing the file (or the file itself if AT_EMPTY_PATH is set)
path	The path to the file

Returns: long 0 on success, or errno on failure

Definition at line 803 of file vfs.c.

Referenced by MOS_STATIC_ASSERT().

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◆ vfs_fsync()

long vfs_fsync	(	io_t *	io,
		bool	sync_metadata,
		off_t	start,
		off_t	end )

Synchronize a file with the filesystem.

Parameters

io	The io object of a file_t
sync_metadata	Whether to sync the metadata
start	The start of the range to sync
end	The end of the range to sync

Returns: long 0 on success, or errno on failure

Definition at line 830 of file vfs.c.

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Variable Documentation

◆ root_dentry

dentry_t* root_dentry

extern

Definition at line 36 of file vfs.c.

Topics

Functions

Variables

Detailed Description

Function Documentation

◆ file_get_ops()

◆ vfs_do_open_dentry()

◆ vfs_register_filesystem()

◆ vfs_mount()

◆ vfs_unmount()

◆ vfs_openat()

◆ vfs_fstatat()

◆ vfs_readlinkat()

◆ vfs_symlink()

◆ vfs_mkdir()

◆ vfs_rmdir()

◆ vfs_list_dir()

◆ vfs_chdirat()

◆ vfs_getcwd()

◆ vfs_fchmodat()

◆ vfs_unlinkat()

◆ vfs_fsync()

Variable Documentation

◆ root_dentry