view src/daemon.c @ 328:b4f766947202

allow multiple dkim signers in authentication results
author Carl Byington <carl@five-ten-sg.com>
date Sun, 18 Dec 2016 17:55:16 -0800
parents 4db1457cd11a
children
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/*Add by Sergey Shapovalov */
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>

/* closeall() -- close all FDs >= a specified value */

void closeall(int fd)
{
	int fdlimit = sysconf(_SC_OPEN_MAX);

	while (fd < fdlimit)
	  close(fd++);
}

/* daemon() - detach process from user and disappear into the background
 * returns -1 on failure, but you can't do much except exit in that case
 * since we may already have forked. This is based on the BSD version,
 * so the caller is responsible for things like the umask, etc.
 */

/* believed to work on all Posix systems */

int daemon(int nochdir, int noclose)
{
	switch (fork())
	{
		case 0:  break;
		case -1: return -1;
		default: _exit(0);			/* exit the original process */
	}

	if (setsid() < 0)				/* shoudn't fail */
	  return -1;

	/* dyke out this switch if you want to acquire a control tty in */
	/* the future -- not normally advisable for daemons */

	switch (fork())
	{
		case 0:  break;
		case -1: return -1;
		default: _exit(0);
	}

	if (!nochdir)
	  chdir("/");

	if (!noclose)
	{
		closeall(0);
		open("/dev/null",O_RDWR);
		dup(0); dup(0);
	}

	return 0;
}