posix.h File Reference

#include <fs/vfs.h>

Go to the source code of this file.

Functions
int	posix_file_open (struct file *file)
	Finishes opening a file: with O_TRUNC, a regular file is truncated to 0 bytes.
int	posix_file_close (struct file *file)
	Closes an open file by dropping its reference to its vnode.
ssize_t	posix_file_read (struct file *file, struct iobuf *io)
	Reads from an open file at its offset, and moves the offset past what was read.
ssize_t	posix_file_write (struct file *file, struct iobuf *io)
	Writes to an open file at its offset, and moves the offset past what was written.
ssize_t	posix_file_readdir (struct file *file, struct dirent *dirent)
	Reads the directory entry at an open directory's offset, and moves the offset past it.
int	posix_file_ioctl (struct file *file, int request, void *argp)
	Passes an ioctl() request on to the file's vnode (a device's, or its filesystem's).
off_t	posix_file_lseek (struct file *file, off_t offset, int whence)
	Moves an open file's offset: to offset (SEEK_SET), by offset from where it is (SEEK_CUR), or by offset from the end of the file (SEEK_END).
int	posix_file_trunc (struct file *file, off_t len)
	Truncates (or extends) an open file to a new length.
int	posix_file_eof (struct file *file)
	Says whether a file's offset is at or past its end, so that a read returns nothing.

Function Documentation

posix_file_close()

int posix_file_close

(

struct file *

file

)

Closes an open file by dropping its reference to its vnode.

Parameters

file	the open file

Returns

0, or a negative errno

Definition at line 15 of file close.c.

References posix_file_close(), and vfs_close().

Referenced by kdev_file_close(), posix_file_close(), ps2mouse_file_close(), vfs_file_close(), and vt_file_close().

posix_file_eof()

int posix_file_eof

(

struct file *

file

)

Says whether a file's offset is at or past its end, so that a read returns nothing.

Parameters

file	the open file

Returns

whether the offset is at the end

Definition at line 17 of file helpers.c.

References file::offset, and posix_file_eof().

Referenced by posix_file_eof().

posix_file_ioctl()

int posix_file_ioctl	(	struct file *	file,
		int	request,
		void *	argp )

Passes an ioctl() request on to the file's vnode (a device's, or its filesystem's).

Parameters

file	the open file
request	the request
argp	its argument, often a pointer to user memory

Returns

the request's result, or a negative errno

Definition at line 19 of file ioctl.c.

References posix_file_ioctl(), and vfs_ioctl().

Referenced by posix_file_ioctl().

posix_file_lseek()

off_t posix_file_lseek	(	struct file *	file,
		off_t	offset,
		int	whence )

Moves an open file's offset: to offset (SEEK_SET), by offset from where it is (SEEK_CUR), or by offset from the end of the file (SEEK_END).

The offset may go past the end of the file.

Parameters

file	the open file
offset	the offset, or the distance to move it
whence	SEEK_SET, SEEK_CUR or SEEK_END

Returns

the new offset, or -EINVAL if whence is wrong or the new offset would be negative

Definition at line 22 of file lseek.c.

References file::offset, posix_file_lseek(), and vnode::size.

Referenced by posix_file_lseek().

posix_file_open()

int posix_file_open

(

struct file *

file

)

Finishes opening a file: with O_TRUNC, a regular file is truncated to 0 bytes.

Parameters

file	the file being opened

Returns

0, or a negative errno if the truncation failed

Definition at line 17 of file open.c.

References file::flags, posix_file_open(), and vfs_file_trunc().

Referenced by kmsg_file_open(), posix_file_open(), ps2mouse_file_open(), and pts_open().

posix_file_read()

ssize_t posix_file_read	(	struct file *	file,
		struct iobuf *	io )

Reads from an open file at its offset, and moves the offset past what was read.

If there is nothing to read yet, it waits for data (a pipe's, a terminal's), unless the file is non-blocking.

Parameters

file	the open file
io	where the data goes, and how much is wanted

Returns

the number of bytes read, 0 at the end of the file, -EAGAIN if a non-blocking read would wait, -ERESTARTSYS if a signal came while it waited, or another negative errno

Definition at line 29 of file read.c.

References arch_rtime_ns(), file::flags, ISDEV, kdev_fops(), NULL, file::offset, posix_file_read(), fops::read_timeout, iobuf::resid, sched_wait(), vfs_file_eof(), vfs_read_io(), VNODE_DEV, and waitq_wakeup().

Referenced by posix_file_read().

posix_file_readdir()

ssize_t posix_file_readdir	(	struct file *	file,
		struct dirent *	dirent )

Reads the directory entry at an open directory's offset, and moves the offset past it.

The offset counts entries, not bytes.

Parameters

file	the open directory
dirent	the entry, filled in

Returns

1 if an entry was read, 0 at the end of the directory, or a negative errno

Definition at line 22 of file readdir.c.

References file::flags, file::offset, posix_file_readdir(), and vfs_readdir().

Referenced by posix_file_readdir().

posix_file_trunc()

int posix_file_trunc	(	struct file *	file,
		off_t	len )

Truncates (or extends) an open file to a new length.

Parameters

file	the open file
len	the new length, in bytes

Returns

0, or a negative errno

Definition at line 16 of file trunc.c.

References posix_file_trunc(), and vfs_trunc().

Referenced by posix_file_trunc().

posix_file_write()

ssize_t posix_file_write	(	struct file *	file,
		struct iobuf *	io )

Writes to an open file at its offset, and moves the offset past what was written.

With O_APPEND, a regular file is written at its end. A blocking write waits for room (in a pipe, say) until everything is written; a non-blocking one writes only if it can without waiting.

Parameters

file	the open file
io	the data, and how much of it

Returns

the number of bytes written, -EAGAIN if a non-blocking write would wait, or a negative errno if nothing was written

Definition at line 25 of file write.c.

References iobuf::fault, file::flags, file::offset, posix_file_write(), iobuf::resid, vfs_file_can_write(), vfs_file_eof(), vfs_write_io(), waitq_sleep(), and waitq_wakeup().

Referenced by posix_file_write().