procfs.c File Reference

Proc file system implementation. More...

Classes
struct	procfs_file_t
	Information concerning a file. More...
struct	procfs_t
	The details regarding the filesystem. More...

Macros
#define	__DEBUG_HEADER__   "[PROCFS]"
	Change header.
#define	__DEBUG_LEVEL__   LOGLEVEL_NOTICE
	Set log level.
#define	PROCFS_NAME_MAX   255U
	Maximum length of name in PROCFS.
#define	PROCFS_MAX_FILES   1024U
	Maximum number of files in PROCFS.
#define	PROCFS_MAGIC_NUMBER   0xBF
	The magic number used to check if the procfs file is valid.

Typedefs
typedef struct procfs_file_t	procfs_file_t
	Information concerning a file.
typedef struct procfs_t	procfs_t
	The details regarding the filesystem. More...

Functions
static int	procfs_mkdir (const char *path, mode_t mode)
	Creates a new directory. More...
static int	procfs_rmdir (const char *path)
	Removes a directory. More...
static int	procfs_stat (const char *path, stat_t *stat)
	Retrieves information concerning the file at the given position. More...
static vfs_file_t *	procfs_open (const char *path, int flags, mode_t mode)
	Open the file at the given path and returns its file descriptor. More...
static int	procfs_unlink (const char *path)
	Deletes the file at the given path. More...
static int	procfs_close (vfs_file_t *file)
	Closes the given file. More...
static ssize_t	procfs_read (vfs_file_t *file, char *buffer, off_t offset, size_t nbyte)
	Reads from the file identified by the file descriptor. More...
static ssize_t	procfs_write (vfs_file_t *file, const void *buffer, off_t offset, size_t nbyte)
	Writes the given content inside the file. More...
static off_t	procfs_lseek (vfs_file_t *file, off_t offset, int whence)
	Repositions the file offset inside a file. More...
static int	procfs_fstat (vfs_file_t *file, stat_t *stat)
	Retrieves information concerning the file at the given position. More...
static int	procfs_ioctl (vfs_file_t *file, int request, void *data)
	Perform the I/O control operation specified by REQUEST on FD. One argument may follow; its presence and type depend on REQUEST. More...
static ssize_t	procfs_getdents (vfs_file_t *file, dirent_t *dirp, off_t doff, size_t count)
	Reads contents of the directories to a dirent buffer, updating the offset and returning the number of written bytes in the buffer, it assumes that all paths are well-formed. More...
static bool_t	procfs_check_file (procfs_file_t *procfs_file)
	Checks if the file is a valid PROCFS file. More...
static procfs_file_t *	procfs_get_file (list_head *entry)
	Returns the PROCFS file associated with the given list entry. More...
static procfs_file_t *	procfs_find_entry_path (const char *path)
	Finds the PROCFS file at the given path. More...
static procfs_file_t *	procfs_find_entry_inode (uint32_t inode)
	Finds the PROCFS file with the given inode. More...
static int	procfs_find_inode (const char *path)
	Finds the inode associated with a PROCFS file at the given path. More...
static int	procfs_get_free_inode (void)
	Finds a free inode. More...
static int	procfs_check_if_empty (const char *path)
	Checks if the PROCFS directory at the given path is empty. More...
static procfs_file_t *	procfs_create_file (const char *path, unsigned flags)
	Creates a new PROCFS file. More...
static int	procfs_destroy_file (procfs_file_t *procfs_file)
	Destroyes the given PROCFS file. More...
static vfs_file_t *	procfs_create_file_struct (procfs_file_t *procfs_file)
	Creates a VFS file, from a PROCFS file. More...
static void	dump_procfs (void)
	Dumps on debugging output the PROCFS.
static int	__procfs_stat (procfs_file_t *file, stat_t *stat)
	Saves the information concerning the file. More...
static vfs_file_t *	procfs_mount (vfs_file_t *block_device, const char *path)
	Mounts the block device as a procfs filesystem. More...
static vfs_file_t *	procfs_mount_callback (const char *path, const char *device)
	Mounts the filesystem at the given path. More...
int	procfs_module_init (void)
	Initialize the procfs filesystem. More...
int	procfs_cleanup_module (void)
	Clean up the procfs filesystem. More...
proc_dir_entry_t *	proc_dir_entry_get (const char *name, proc_dir_entry_t *parent)
	Finds the direntry inside /proc or under the given parent. More...
proc_dir_entry_t *	proc_mkdir (const char *name, proc_dir_entry_t *parent)
	Creates a new directory inside the procfs filesystem. More...
int	proc_rmdir (const char *name, proc_dir_entry_t *parent)
	Removes a directory from the procfs filesystem. More...
proc_dir_entry_t *	proc_create_entry (const char *name, proc_dir_entry_t *parent)
	Creates a new entry inside the procfs filesystem. More...
int	proc_destroy_entry (const char *name, proc_dir_entry_t *parent)
	Removes an entry from the procfs filesystem. More...
int	proc_entry_set_mask (proc_dir_entry_t *entry, mode_t mask)
	Sets the mask of a given procfs entry. More...

Variables
procfs_t	fs
	The procfs filesystem.
static vfs_sys_operations_t	procfs_sys_operations
	Filesystem general operations. More...
static vfs_file_operations_t	procfs_fs_operations
	Filesystem file operations. More...
static file_system_type	procfs_file_system_type
	Filesystem information. More...

Detailed Description

Proc file system implementation.

Copyright

(c) 2014-2024 This file is distributed under the MIT License. See LICENSE.md for details.

Typedef Documentation

procfs_t

typedef struct procfs_t procfs_t

The details regarding the filesystem.

Contains the number of files inside the procfs filesystem.

Function Documentation

__procfs_stat()

static int __procfs_stat ( procfs_file_t *  file, stat_t *  stat  )

static

Saves the information concerning the file.

Parameters

file	The file containing the data.
stat	The structure where the information are stored.

Returns

0 if success.

proc_create_entry()

proc_dir_entry_t* proc_create_entry	(	const char *	name,
		proc_dir_entry_t *	parent
	)

Creates a new entry inside the procfs filesystem.

Parameters

name	The name of the entry we are creating.
parent	The parent (optional).

Returns

A pointer to the entry, or NULL if fails.

proc_destroy_entry()

int proc_destroy_entry	(	const char *	name,
		proc_dir_entry_t *	parent
	)

Removes an entry from the procfs filesystem.

Parameters

name	The name of the entry we are removing.
parent	The parent (optional).

Returns

0 if succeed, or -errno in case of error.

proc_dir_entry_get()

proc_dir_entry_t* proc_dir_entry_get	(	const char *	name,
		proc_dir_entry_t *	parent
	)

Finds the direntry inside /proc or under the given parent.

Parameters

name	The name of the entry we are searching.
parent	The parent (optional).

Returns

A pointer to the entry, or NULL.

proc_entry_set_mask()

int proc_entry_set_mask	(	proc_dir_entry_t *	entry,
		mode_t	mask
	)

Sets the mask of a given procfs entry.

Parameters

entry	Pointer to the entry.
mask	The mask to set.

Returns

0 if succeed, or -errno in case of error.

proc_mkdir()

proc_dir_entry_t* proc_mkdir	(	const char *	name,
		proc_dir_entry_t *	parent
	)

Creates a new directory inside the procfs filesystem.

Parameters

name	The name of the entry we are creating.
parent	The parent (optional).

Returns

A pointer to the entry, or NULL if fails.

proc_rmdir()

int proc_rmdir	(	const char *	name,
		proc_dir_entry_t *	parent
	)

Removes a directory from the procfs filesystem.

Parameters

name	The name of the entry we are removing.
parent	The parent (optional).

Returns

0 if succeed, or -errno in case of error.

procfs_check_file()

static bool_t procfs_check_file ( procfs_file_t *  procfs_file )

inlinestatic

Checks if the file is a valid PROCFS file.

Parameters

procfs_file

the file to check.

Returns

true if valid, false otherwise.

procfs_check_if_empty()

static int procfs_check_if_empty ( const char *  path )

inlinestatic

Checks if the PROCFS directory at the given path is empty.

Parameters

path	the path to the directory.

Returns

0 if empty, 1 if not.

procfs_cleanup_module()

int procfs_cleanup_module

(

void

)

Clean up the procfs filesystem.

Returns

0 if fails, 1 if succeed.

procfs_close()

static int procfs_close ( vfs_file_t *  file )

static

Closes the given file.

Parameters

file	The file structure.

Returns

0 on success, -errno on failure.

procfs_create_file()

static procfs_file_t* procfs_create_file ( const char *  path, unsigned  flags  )

inlinestatic

Creates a new PROCFS file.

Parameters

path	where the file resides.
flags	the creation flags.

Returns

a pointer to the new PROCFS file, NULL otherwise.

procfs_create_file_struct()

static vfs_file_t* procfs_create_file_struct ( procfs_file_t *  procfs_file )

inlinestatic

Creates a VFS file, from a PROCFS file.

Parameters

procfs_file

the PROCFS file.

Returns

a pointer to the newly create VFS file, NULL on failure.

procfs_destroy_file()

static int procfs_destroy_file ( procfs_file_t *  procfs_file )

inlinestatic

Destroyes the given PROCFS file.

Parameters

procfs_file

pointer to the PROCFS file to destroy.

Returns

0 on success, 1 on failure.

procfs_find_entry_inode()

static procfs_file_t* procfs_find_entry_inode ( uint32_t  inode )

inlinestatic

Finds the PROCFS file with the given inode.

Parameters

inode

the inode we search.

Returns

a pointer to the PROCFS file, NULL otherwise.

procfs_find_entry_path()

static procfs_file_t* procfs_find_entry_path ( const char *  path )

inlinestatic

Finds the PROCFS file at the given path.

Parameters

path	the path to the entry.

Returns

a pointer to the PROCFS file, NULL otherwise.

procfs_find_inode()

static int procfs_find_inode ( const char *  path )

inlinestatic

Finds the inode associated with a PROCFS file at the given path.

Parameters

path	the path to the entry.

Returns

a valid inode, or -1 on failure.

procfs_fstat()

static int procfs_fstat ( vfs_file_t *  file, stat_t *  stat  )

static

Retrieves information concerning the file at the given position.

Parameters

file	The file struct.
stat	The structure where the information are stored.

Returns

0 if success.

procfs_get_file()

static procfs_file_t* procfs_get_file ( list_head *  entry )

inlinestatic

Returns the PROCFS file associated with the given list entry.

Parameters

entry

the entry to transform to PROCFS file.

Returns

a valid pointer to a PROCFS file, NULL otherwise.

procfs_get_free_inode()

static int procfs_get_free_inode ( void  )

inlinestatic

Finds a free inode.

Returns

the free inode index, or -1 on failure.

procfs_getdents()

static ssize_t procfs_getdents ( vfs_file_t *  file, dirent_t *  dirp, off_t  doff, size_t  count  )

inlinestatic

Reads contents of the directories to a dirent buffer, updating the offset and returning the number of written bytes in the buffer, it assumes that all paths are well-formed.

Parameters

file	The directory handler.
dirp	The buffer where the data should be written.
doff	The offset inside the buffer where the data should be written.
count	The maximum length of the buffer.

Returns

The number of written bytes in the buffer.

procfs_ioctl()

static int procfs_ioctl ( vfs_file_t *  file, int  request, void *  data  )

static

Perform the I/O control operation specified by REQUEST on FD. One argument may follow; its presence and type depend on REQUEST.

Parameters

file	the file on which we perform the operations.
request	the device-dependent request code
data	an untyped pointer to memory.

Returns

Return value depends on REQUEST. Usually -1 indicates error.

procfs_lseek()

off_t procfs_lseek ( vfs_file_t *  file, off_t  offset, int  whence  )

static

Repositions the file offset inside a file.

Parameters

file	the file we are working with.
offset	the offest to use for the operation.
whence	the type of operation.

Returns

Upon successful completion, returns the resulting offset location as measured in bytes from the beginning of the file. On error, the value (off_t) -1 is returned and errno is set to indicate the error.

procfs_mkdir()

static int procfs_mkdir ( const char *  path, mode_t  mode  )

static

Creates a new directory.

Parameters

path	The path to the new directory.
mode	The file mode.

Returns

0 if success.

procfs_module_init()

int procfs_module_init

(

void

)

Initialize the procfs filesystem.

Returns

0 if fails, 1 if succeed.

procfs_mount()

static vfs_file_t* procfs_mount ( vfs_file_t *  block_device, const char *  path  )

static

Mounts the block device as a procfs filesystem.

Parameters

block_device	the block device formatted as procfs.
path	location where we mount the filesystem.

Returns

the VFS root node of the procfs filesystem.

procfs_mount_callback()

static vfs_file_t* procfs_mount_callback ( const char *  path, const char *  device  )

static

Mounts the filesystem at the given path.

Parameters

path	the path where we want to mount a procfs.
device	we expect it to be NULL.

Returns

a pointer to the root VFS file.

procfs_open()

static vfs_file_t * procfs_open ( const char *  path, int  flags, mode_t  mode  )

static

Open the file at the given path and returns its file descriptor.

Parameters

path	The path to the file.
flags	The flags used to determine the behavior of the function.
mode	The mode with which we open the file.

Returns

The file descriptor of the opened file, otherwise returns -1.

procfs_read()

static ssize_t procfs_read ( vfs_file_t *  file, char *  buffer, off_t  offset, size_t  nbyte  )

static

Reads from the file identified by the file descriptor.

Parameters

file	The file.
buffer	Buffer where the read content must be placed.
offset	Offset from which we start reading from the file.
nbyte	The number of bytes to read.

Returns

The number of red bytes.

procfs_rmdir()

static int procfs_rmdir ( const char *  path )

static

Removes a directory.

Parameters

path	The path to the directory.

Returns

0 if success.

procfs_stat()

static int procfs_stat ( const char *  path, stat_t *  stat  )

static

Retrieves information concerning the file at the given position.

Parameters

path	The path to the file.
stat	The structure where the information are stored.

Returns

0 if success.

procfs_unlink()

static int procfs_unlink ( const char *  path )

inlinestatic

Deletes the file at the given path.

Parameters

path	The path to the file.

Returns

On success, zero is returned. On error, -1 is returned.

procfs_write()

static ssize_t procfs_write ( vfs_file_t *  file, const void *  buffer, off_t  offset, size_t  nbyte  )

static

Writes the given content inside the file.

Parameters

file	The file descriptor of the file.
buffer	The content to write.
offset	Offset from which we start writing in the file.
nbyte	The number of bytes to write.

Returns

The number of written bytes.

Variable Documentation

procfs_file_system_type

file_system_type procfs_file_system_type

static

Initial value:

= {
    .name     = "procfs",
    .fs_flags = 0,
    .mount    = procfs_mount_callback
}

Filesystem information.

procfs_fs_operations

vfs_file_operations_t procfs_fs_operations

static

Initial value:

= {
    .open_f     = procfs_open,
    .unlink_f   = procfs_unlink,
    .close_f    = procfs_close,
    .read_f     = procfs_read,
    .write_f    = procfs_write,
    .lseek_f    = procfs_lseek,
    .stat_f     = procfs_fstat,
    .ioctl_f    = procfs_ioctl,
    .getdents_f = procfs_getdents,
    .readlink_f = NULL,
}

Filesystem file operations.

procfs_sys_operations

vfs_sys_operations_t procfs_sys_operations

static

Initial value:

= {
    .mkdir_f   = procfs_mkdir,
    .rmdir_f   = procfs_rmdir,
    .stat_f    = procfs_stat,
    .creat_f   = NULL,
    .symlink_f = NULL,
}

Filesystem general operations.