/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#include "lint.h"

#include "file64.h"

#include "mtlib.h"

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include "stdiom.h"

/*

 * Use fork/setsid/fork to go into background and permanently remove

 * controlling terminal.

 */

int

daemon(int nochdir, int noclose)

{

	int retv, fd;

	/*

	 * By the first fork+setsid, we disconnect from our current controlling

	 * terminal and become a session group leader.

	 */

	retv = fork();

	if (retv == -1)

		return (-1);

	if (retv != 0)

		_exit(EXIT_SUCCESS);

	if (setsid() == -1)

		return (-1);

	/*

	 * By forking again without calling setsid again, we make certain

	 * that we are not the session group leader and can never reacquire

	 * a controlling terminal.

	 */

	retv = fork();

	if (retv == -1)

		return (-1);

	if (retv != 0)

		_exit(EXIT_SUCCESS);

	if (nochdir == 0)

		(void) chdir("/");

	if (noclose == 0) {

		/*

		 * Missing the PRIV_FILE_READ privilege may be one of the

		 * reasons that prevent the opening of /dev/null to succeed.

		 */

		if ((fd = open("/dev/null", O_RDWR)) == -1)

			return (-1);

		/*

		 * Also, if any of the descriptor redirects fails we should

		 * return with error to signal to the caller that his request

		 * cannot be fulfilled properly. It is up to the caller to

		 * do the cleanup.

		 */

		if ((fd != STDIN_FILENO) && (dup2(fd, STDIN_FILENO) < 0)) {

			(void) close(fd);

			return (-1);

		}

		if ((fd != STDOUT_FILENO) && (dup2(fd, STDOUT_FILENO) < 0)) {

			(void) close(fd);

			return (-1);

		}

		if ((fd != STDERR_FILENO) && (dup2(fd, STDERR_FILENO) < 0)) {

			(void) close(fd);

			return (-1);

		}

		if (fd > STDERR_FILENO)

			(void) close(fd);

	}

	return (0);

}