daemon.c

根据网络原始数据生成NetFlow记录的软件。NetFlow是Cisco提出的流技术

/* OPENBSD ORIGINAL: lib/libc/gen/daemon.c */

/*-
 * 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. 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.
 */

#include "common.h"

#ifndef HAVE_DAEMON

#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: daemon.c,v 1.5 2003/07/15 17:32:41 deraadt Exp $";
#endif /* LIBC_SCCS and not lint */

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

	switch (fork()) {
	case -1:
		return (-1);
	case 0:
#ifdef HAVE_CYGWIN
		register_9x_service();
#endif
		break;
	default:
#ifdef HAVE_CYGWIN
		/*
		 * This sleep avoids a race condition which kills the
		 * child process if parent is started by a NT/W2K service.
		 */
		sleep(1);
#endif
		_exit(0);
	}

	if (setsid() == -1)
		return (-1);

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

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

#endif /* !HAVE_DAEMON */