fd.c File Reference

File descriptor output redirection implementation. More...

#include "fd.h"
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "log.h"

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Functions
static int	openfd (const char *name, const unsigned int id)
	Opens, or creates, a truncated file using a formatted path derived from the provided name and id arguments.
static void	closefd (int *fd)
	Closes the file descriptor if open (indicated by a value of >=0) and sets it to -1.
int	fdinit (struct fdset_s *fds, const unsigned int id)
	Initializes stdout/stderr files used for redirecting output from a child process. The file descriptors are stored in the provided file descriptor set. The files are opened in write-only mode and are created if they do not exist. If either file fails to open, the function will return -1 and both file descriptors will be set to -1.
void	fdclose (struct fdset_s *fds)
	Closes the stdout and stderr file descriptors in the provided file descriptor set using close(2). If either file descriptor is already closed, the function will not attempt to close it again.

Detailed Description

File descriptor output redirection implementation.

Function Documentation

closefd()

void closefd ( int * fd )

static

Closes the file descriptor if open (indicated by a value of >=0) and sets it to -1.

Parameters

fd	Pointer to the file descriptor to close, must not be NULL.

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fdclose()

void fdclose

(

struct fdset_s *

fds

)

Closes the stdout and stderr file descriptors in the provided file descriptor set using close(2). If either file descriptor is already closed, the function will not attempt to close it again.

Parameters

fds	The file descriptor set to close

Note

The file descriptors must be initialized with fdinit before calling this function.

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fdinit()

int fdinit	(	struct fdset_s *	fds,
		unsigned int	id )

Initializes stdout/stderr files used for redirecting output from a child process. The file descriptors are stored in the provided file descriptor set. The files are opened in write-only mode and are created if they do not exist. If either file fails to open, the function will return -1 and both file descriptors will be set to -1.

Parameters

fds	The file descriptor set to initialize
id	Unique identifier to append to the file name

Returns

0 if both files were opened successfully, otherwise -1

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openfd()

int openfd ( const char * name, const unsigned int id )

static

Opens, or creates, a truncated file using a formatted path derived from the provided name and id arguments.

Parameters

name	The base name of the file to open
id	The unique identifier to append to the file name

Returns

The file descriptor of the opened file, or -1 on error

Note

Due to a fixed-size buffer, the formatted file path has a maximum length of 31 characters.

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