daemon.c

linux-ftpd-0.17.tar.gz linux 嵌入式 tftpd

/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * From: @(#)daemon.c	8.1 (Berkeley) 6/4/93
 *       NetBSD: daemon.c,v 1.4 1995/02/25 13:41:16 cgd Exp
 */
char daemon_rcsid[] = 
  "$Id: daemon.c,v 1.1.1.1 1999/07/15 21:57:44 dholland Exp $";

#include <fcntl.h>
#include <paths.h>
#include <unistd.h>

#include "daemon.h"

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

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

	if (setsid() == -1) return -1;
	if (!nochdir) chdir("/");
	if (noclose) return 0;

	fd = open(_PATH_DEVNULL, O_RDWR, 0);
	if (fd != -1) {
		dup2(fd, STDIN_FILENO);
		dup2(fd, STDOUT_FILENO);
		dup2(fd, STDERR_FILENO);
		if (fd > 2) close(fd);
	}
	return 0;
}