daemonize.c File Reference

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>

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Macros
#define	WORKDIR   "/"
#define	UMASK   0

Functions
void	daemonize (void)

Detailed Description

Disconnect from parent process and let all standard file handles point to /dev/null.

Author

Georg Hopp

Copyright

Copyright © 2012 Georg Hopp

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Definition in file daemonize.c.

Macro Definition Documentation

#define UMASK   0

Definition at line 36 of file daemonize.c.

Referenced by daemonize().

#define WORKDIR   "/"

Definition at line 35 of file daemonize.c.

Function Documentation

void daemonize

(

void

)

Definition at line 38 of file daemonize.c.

References UMASK.

Referenced by main().

                     {
    pid_t pid;

    if (0 > ((pid = fork()))) {
        perror("deamoinze[fork]");
        exit(EXIT_FAILURE);
    } else if (0 != pid) {
        exit(EXIT_SUCCESS);
    }

    // make new child session leader
    setsid();

    if (0 > ((pid = fork()))) {
        perror("deamoinze[fork]");
        exit(EXIT_FAILURE);
    } else if (0 != pid) {
        exit(EXIT_SUCCESS);
    }

    // set umask and change to working directory to /
    umask(UMASK);
    if (-1 == chdir("/")) {
        perror("daemonize");
        exit(EXIT_FAILURE);
    }

    // we should close all open filedescriptors now.
    // But I assume that this function is called at the very start of the
    // program and no more filedescriptors are open than the standard
    // ones.

    // connect all standard streams to /dev/null
    stderr = freopen("/dev/null", "w", stderr);
    stdin  = freopen("/dev/null", "r", stdin);
    stdout = freopen("/dev/null", "w", stdout);
}

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