How to Daemonize in Linux

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

#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1

static void daemonize(void)
{
pid_t pid, sid;

/* already a daemon */
if (getppid() == 1) {
return;
}

/* Fork off the parent process */
pid = fork();
if (pid < 0) {
exit(EXIT_FAILURE);
}
/* If we got a good PID, then we can exit the parent process. */
if (pid > 0) {
exit(EXIT_SUCCESS);
}

/* At this point we are executing as the child process */

/* Change the file mode mask */
umask(0);

/* Create a new SID for the child process */
sid = setsid();
if (sid < 0) {
exit(EXIT_FAILURE);
}

/* Change the current working directory.  This prevents the current
*        directory from being locked; hence not being able to remove it. */
if ((chdir("/")) < 0) {
exit(EXIT_FAILURE);
}

/* Redirect standard files to /dev/null */
freopen("/dev/null", "r", stdin);
freopen("/dev/null", "w", stdout);
freopen("/dev/null", "w", stderr);
}

int main(int argc, char **argv)
{
daemonize();

/* Now we are a daemon -- do the work for which we were paid */

while (1) {
sleep(1);
}

return 0;
}