daemon.c

#include <unistd.h>
#include <sys/stat.h>
#include <signal.h>
#include <stdlib.h>

void skeleton_daemon()
{
	pid_t pid;

	/* Fork off the parent process */
	pid = fork();

	/* An error occurred */
	if (pid < 0)
		exit(EXIT_FAILURE);

	/* Success: Let the parent terminate */
	if (pid > 0)
		exit(EXIT_SUCCESS);

	/* On success: The child process becomes session leader */
	if (setsid() < 0)
		exit(EXIT_FAILURE);

	/* Catch, ignore and handle signals */
	//TODO: Implement a working signal handler */
	signal(SIGCHLD, SIG_IGN);
	signal(SIGHUP, SIG_IGN);


	/* Fork off for the second time*/
	pid = fork();

	/* An error occurred */
	if (pid < 0)
		exit(EXIT_FAILURE);

	/* Success: Let the parent terminate */
	if (pid > 0)
		exit(EXIT_SUCCESS);

	/* Set new file permissions */
	umask(0);

	/* Change the working directory to the root directory */
	/* or another appropriated directory */
	if(chdir("/") != 0) exit(EXIT_FAILURE);

	/* Close all open file descriptors */
	/*
	int x;
	for (x = sysconf(_SC_OPEN_MAX); x>0; x--)
	{
		close(x);
	}*/

	close(0); close(1); close(2); //stdin stdout stderr

	/* Open the log file */
	//openlog("ddnsclient", LOG_PID, LOG_DAEMON);
}