Input/Output routines

Functionality includes closing descriptors of current process, running server as a daemon, recursive remove of a directory or a file, opening and locking file, closing file. More...

Collaboration diagram for Input/Output routines:

Functions
int	closeall (int nostdclose)
	close all file descriptors of current process More...
pid_t	daemonize (const char *path, char *const argv[], int nochdir, int noclose)
	run program as daemon More...
int	pidlock_set (const char *path)
	try to save pid of calling process to file More...
pid_t	pidlock_get (const char *path)
	read pid from file and verify it More...
int	dir_remove (const char *path)
	recursive remove directory or file More...
int	mkdirectory (const char *path, mode_t mode)
	verify or create directory More...
int	executefile (const char *path)
	execute file as program More...
int	put_file_contents (const char *path, const void *buf, size_t len)
	save data to file More...
void *	get_file_contents (const char *path, void **buf, size_t *len)
	allocate memory and read data from file More...
FILE *	flopen (const char *path, const char *mode, FILE **fp)
	open and lock file More...
FILE *	fltryopen (const char *path, const char *mode, FILE **fp)
	open and try lock file More...
int	flclose (FILE *fp)
	close file openned by flopen() or fltryopen() More...
int	movefile (const char *oldpath, const char *newpath)
	move file to new path More...

Detailed Description

Functionality includes closing descriptors of current process, running server as a daemon, recursive remove of a directory or a file, opening and locking file, closing file.

Function Documentation

int closeall

(

int

nostdclose

)

close all file descriptors of current process

Parameters

[in]

nostdclose

don't close stdio file descriptors

Returns

zero is returned

Return values

-1	error occurred

This function can be useful for implementation system() like functions.

pid_t daemonize	(	const char *	path,
		char *const	argv[],
		int	nochdir,
		int	noclose
	)

run program as daemon

Parameters

[in]	path	path to program file
[in]	argv	arguments for program (last item should be NULL)
[in]	nochdir	don't change current directory to '/' for daemon
[in]	noclose	don't close stdio streams for daemon

Returns

pid of started daemon

Return values

-1	error occured

int dir_remove

(

const char *

path

)

recursive remove directory or file

Parameters

[in]

path

name of directory or file

Returns

on success, zero is returned

Function updates errno if error occurred:

• ENOMEM no memory format path

If function fails to delete directory (file) it will continue to delete rest of the directories (files), but don't return zero.

int executefile

(

const char *

path

)

execute file as program

Parameters

[in]

path

path to executable file

Returns

status code of child process

Return values

-1	error occurred

int flclose

(

FILE *

fp

)

close file openned by flopen() or fltryopen()

Parameters

[in]

fp

file descriptor (can be NULL)

Returns

on success, zero is returned

Return values

-1	error occurred

If error occurred function update errno - see errors specified for the routines fileno(3), flock(2), and fclose(3).

FILE* flopen	(	const char *	path,
		const char *	mode,
		FILE **	fp
	)

open and lock file

Parameters

[in]	path	name of the file to be created or opened
[in]	mode	permissive mode
[out]	fp	file descriptor

Returns

pointer to descriptor

Return values

NULL	error occurred, fp also should be NULL

If error occurred function update errno - see errors specified for the routines fopen(3), fileno(3), flock(2), and fclose(3).

FILE* fltryopen	(	const char *	path,
		const char *	mode,
		FILE **	fp
	)

open and try lock file

Parameters

[in]	path	name of the file to be created or opened
[in]	mode	permissive mode
[out]	fp	file descriptor

Returns

pointer to descriptor

Return values

NULL	error occurred, fp also should be NULL

If error occurred function update errno - see errors specified for the routines fopen(3), fileno(3), flock(2), and fclose(3).

void* get_file_contents	(	const char *	path,
		void **	buf,
		size_t *	len
	)

allocate memory and read data from file

Parameters

[in]	path	file name
[out]	buf	pointer to file data
[out]	len	pointer to file length

Returns

on success pointer to allocated memory

Return values

NULL	error occurred

int mkdirectory	(	const char *	path,
		mode_t	mode
	)

verify or create directory

Parameters

[in]	path	directory name
[in]	mode	directory permissions

Returns

zero returned

Return values

-1	error occurred

This function make parent directories, if needed.

int movefile	(	const char *	oldpath,
		const char *	newpath
	)

move file to new path

Parameters

[in]	oldpath	filename to move
[in]	newpath	new path of file

Returns

zero is returned

Return values

-1	error occured, check errno for more info

When oldpath and newpath on the same filesystem - rename() syscall will be used. If rename() syscall failed function will try create new and delete old file.

pid_t pidlock_get

(

const char *

path

)

read pid from file and verify it

Parameters

[in]

path

name of pid file

Returns

pid of process

Return values

0	process don't exist
-1	error occurred

If error occurred function update errno - see errors specified for the routines flopen(), flclose(), fscanf(3) and kill(2).

int pidlock_set

(

const char *

path

)

try to save pid of calling process to file

Parameters

[in]

path

name of pid file

Returns

on success, zero is returned

Return values

-1	error occurred

Function fail, if another process already set pidlock.

If error occurred function update errno - see errors specified for the routines fltryopen(), flclose(), fscanf(3), fprintf(3), ftruncate(2) and kill(2).

int put_file_contents	(	const char *	path,
		const void *	buf,
		size_t	len
	)

save data to file

Parameters

[in]	path	file name
[in]	buf	pointer to data buffer
[in]	len	length of data at buffer buf

Returns

on success, zero is returned

Return values

-1	error occurred