4.3BSD-Reno/src/lib/libutil/daemon.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * Neither the name of the University nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)daemon.c	1.2 (Berkeley) 6/29/90";
#endif /* LIBC_SCCS and not lint */

#include <sys/file.h>

daemon(nochdir, noclose)
	int nochdir, noclose;
{
	int cpid;

	if ((cpid = fork()) == -1)
		return (-1);
	if (cpid)
		exit(0);
	(void) setsid();
	if (!nochdir)
		(void) chdir("/");
	if (!noclose) {
		int devnull = open("/dev/null", O_RDWR, 0);

		if (devnull != -1) {
			(void) dup2(devnull, 0);
			(void) dup2(devnull, 1);
			(void) dup2(devnull, 2);
			if (devnull > 2)
				(void) close(devnull);
		}
	}
}