Virtual File System

Virtual File System. More...

Collaboration diagram for Virtual File System:

Detailed Description

Virtual File System.

The Virtual File System (VFS) provides a single unified interface for any and all filesystems, including virtual filesystems used to expose kernel resources to user space.

Macros
#define	VFS_ROOT_ENTRY_NAME   "__root__"
	The name of the root entry.
#define	VFS_DEVICE_NAME_NONE   "__no_device__"
	The name used to indicate no device.
#define	BUFFER_READ(buffer, count, offset, src, size)
	Helper macros for implementing file operations dealing with simple buffers.
#define	BUFFER_WRITE(buffer, count, offset, src, size)
	Helper macro for implementing file operations dealing with simple buffer writes.

Functions
file_t *	vfs_open (const pathname_t *pathname, process_t *process)
	Open a file.
uint64_t	vfs_open2 (const pathname_t *pathname, file_t *files[2], process_t *process)
	Open one file, returning two file handles.
file_t *	vfs_openat (const path_t *from, const pathname_t *pathname, process_t *process)
	Open a file relative to another path.
uint64_t	vfs_read (file_t *file, void *buffer, uint64_t count)
	Read from a file.
uint64_t	vfs_write (file_t *file, const void *buffer, uint64_t count)
	Write to a file.
uint64_t	vfs_seek (file_t *file, int64_t offset, seek_origin_t origin)
	Seek in a file.
uint64_t	vfs_ioctl (file_t *file, uint64_t request, void *argp, uint64_t size)
	Perform an ioctl operation on a file.
void *	vfs_mmap (file_t *file, void *address, uint64_t length, pml_flags_t flags)
	Memory map a file.
uint64_t	vfs_poll (poll_file_t *files, uint64_t amount, clock_t timeout)
	Poll multiple files.
uint64_t	vfs_getdents (file_t *file, dirent_t *buffer, uint64_t count)
	Get directory entries from a directory file.
uint64_t	vfs_stat (const pathname_t *pathname, stat_t *buffer, process_t *process)
	Get file information.
uint64_t	vfs_link (const pathname_t *oldPathname, const pathname_t *newPathname, process_t *process)
	Make the same file appear twice in the filesystem.
uint64_t	vfs_remove (const pathname_t *pathname, process_t *process)
	Remove a file or directory.
uint64_t	vfs_id_get (void)
	Generates a new unique ID, to be used for any VFS object.

Macro Definition Documentation

VFS_ROOT_ENTRY_NAME

#define VFS_ROOT_ENTRY_NAME   "__root__"

The name of the root entry.

Definition at line 32 of file vfs.h.

VFS_DEVICE_NAME_NONE

#define VFS_DEVICE_NAME_NONE   "__no_device__"

The name used to indicate no device.

Definition at line 37 of file vfs.h.

BUFFER_READ

#define BUFFER_READ	(		buffer,
			count,
			offset,
			src,
			size
	)

Value:

    ({ \
        uint64_t readCount = (*(offset) <= (size)) ? MIN((count), (size) - *(offset)) : 0; \
        memcpy((buffer), (src) + *(offset), readCount); \
        *(offset) += readCount; \
        readCount; \
    })

Helper macros for implementing file operations dealing with simple buffers.

Parameters

buffer	The destination buffer.
count	The number of bytes to read/write.
offset	A pointer to the current offset, will be updated.
src	The source buffer.
size	The size of the source buffer.

Returns

The number of bytes read/written.

Definition at line 194 of file vfs.h.

BUFFER_WRITE

#define BUFFER_WRITE	(		buffer,
			count,
			offset,
			src,
			size
	)

Value:

    ({ \
        uint64_t writeCount = (*(offset) <= (size)) ? MIN((count), (size) - *(offset)) : 0; \
        memcpy((buffer) + *(offset), (src), writeCount); \
        *(offset) += writeCount; \
        writeCount; \
    })

Helper macro for implementing file operations dealing with simple buffer writes.

Parameters

buffer	The destination buffer.
count	The number of bytes to write.
offset	A pointer to the current offset, will be updated.
src	The source buffer.
size	The size of the source buffer.

Returns

The number of bytes written.

Definition at line 212 of file vfs.h.

Function Documentation

vfs_open()

file_t * vfs_open	(	const pathname_t *	pathname,
		process_t *	process
	)

Open a file.

Parameters

pathname	The pathname of the file to open.
process	The process opening the file.

Returns

On success, the opened file. On failure, returns NULL and errno is set.

Definition at line 94 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_open2()

uint64_t vfs_open2	(	const pathname_t *	pathname,
		file_t *	files[2],
		process_t *	process
	)

Open one file, returning two file handles.

Used primarily to implement pipes.

Parameters

pathname	The pathname of the file to open.
files	The output array of two file pointers.
process	The process opening the file.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 108 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_openat()

file_t * vfs_openat	(	const path_t *	from,
		const pathname_t *	pathname,
		process_t *	process
	)

Open a file relative to another path.

Parameters

from	The path to open the file relative to.
pathname	The pathname of the file to open.
process	The process opening the file.

Returns

On success, the opened file. On failure, returns NULL and errno is set.

Definition at line 158 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_read()

uint64_t vfs_read	(	file_t *	file,
		void *	buffer,
		uint64_t	count
	)

Read from a file.

Follows POSIX semantics.

Parameters

file	The file to read from.
buffer	The buffer to read into.
count	The number of bytes to read.

Returns

On success, the number of bytes read. On failure, ERR and errno is set.

Definition at line 200 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_write()

uint64_t vfs_write	(	file_t *	file,
		const void *	buffer,
		uint64_t	count
	)

Write to a file.

Follows POSIX semantics.

Parameters

file	The file to write to.
buffer	The buffer to write from.
count	The number of bytes to write.

Returns

On success, the number of bytes written. On failure, ERR and errno is set.

Definition at line 239 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_seek()

uint64_t vfs_seek	(	file_t *	file,
		int64_t	offset,
		seek_origin_t	origin
	)

Seek in a file.

Follows POSIX semantics.

Parameters

file	The file to seek in.
offset	The offset to seek to.
origin	The origin to seek from.

Returns

On success, the new file position. On failure, ERR and errno is set.

Definition at line 286 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_ioctl()

uint64_t vfs_ioctl	(	file_t *	file,
		uint64_t	request,
		void *	argp,
		uint64_t	size
	)

Perform an ioctl operation on a file.

Parameters

file	The file to perform the ioctl on.
request	The ioctl request.
argp	The argument pointer.
size	The size of the argument.

Returns

On success, the result of the ioctl. On failure, ERR and errno is set.

Definition at line 304 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_mmap()

void * vfs_mmap	(	file_t *	file,
		void *	address,
		uint64_t	length,
		pml_flags_t	flags
	)

Memory map a file.

Parameters

file	The file to memory map.
address	The address to map to, or NULL to let the kernel choose.
length	The length to map.
flags	The page table flags for the mapping.

Returns

On success, the mapped address. On failure, returns NULL and errno is set.

Definition at line 333 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_poll()

uint64_t vfs_poll	(	poll_file_t *	files,
		uint64_t	amount,
		clock_t	timeout
	)

Poll multiple files.

Parameters

files	The array of files to poll.
amount	The number of files in the array.
timeout	The timeout in clock ticks, or CLOCKS_NEVER to wait indefinitely.

Returns

On success, the number of files that are ready. On failure, ERR and errno is set.

Definition at line 440 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_getdents()

uint64_t vfs_getdents	(	file_t *	file,
		dirent_t *	buffer,
		uint64_t	count
	)

Get directory entries from a directory file.

Parameters

file	The directory file to read from.
buffer	The buffer to read into.
count	The number of bytes to read.

Returns

On success, the number of bytes read. On failure, ERR and errno is set.

Definition at line 515 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_stat()

uint64_t vfs_stat	(	const pathname_t *	pathname,
		stat_t *	buffer,
		process_t *	process
	)

Get file information.

Parameters

pathname	The pathname of the file to get information about.
buffer	The buffer to store the file information in.
process	The process performing the stat.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 556 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_link()

uint64_t vfs_link	(	const pathname_t *	oldPathname,
		const pathname_t *	newPathname,
		process_t *	process
	)

Make the same file appear twice in the filesystem.

Parameters

oldPathname	The existing file.
newPathname	The new link to create, must not exist and be in the same filesystem as the oldPathname.
process	The process performing the linking.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 609 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_remove()

uint64_t vfs_remove	(	const pathname_t *	pathname,
		process_t *	process
	)

Remove a file or directory.

Parameters

pathname	The pathname of the file or directory to remove.
process	The process performing the removal.

Returns

On success, 0. On failure, ERR and errno is set.

Definition at line 698 of file vfs.c.

Here is the call graph for this function:

Here is the caller graph for this function:

vfs_id_get()

uint64_t vfs_id_get

(

void

)

Generates a new unique ID, to be used for any VFS object.

Returns

A new unique ID.

Definition at line 765 of file vfs.c.

Here is the caller graph for this function: