Libc-498.tar.gz

[apple/libc.git] / util / pty.c

/*
 * Copyright (c) 1999, 2007 Apple Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1990, 1993, 1994
 *	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.
 */


#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <util.h>
#include <syslog.h>

static char ptytemplate[] = "/dev/ptyXX";

int openpty(amaster, aslave, name, termp, winp)
	int *amaster, *aslave;
	char *name;
	struct termios *termp;
	struct winsize *winp;
{
	int master, slave;
	char *sname;

	if ((master = posix_openpt(O_RDWR|O_NOCTTY)) < 0)
		return -1;
	if (grantpt(master) < 0 || unlockpt(master) < 0
	    || (sname = ptsname(master)) == NULL
	    || (slave = open(sname, O_RDWR|O_NOCTTY, 0)) < 0) {
		(void) close(master);
		return -1;
	}
	*amaster = master;
	*aslave = slave;
	if (name)
		strcpy(name, sname);
	if (termp)
		(void) tcsetattr(slave, TCSAFLUSH, termp);
	if (winp)
		(void) ioctl(slave, TIOCSWINSZ, (char *)winp);
	return (0);
}

int
forkpty(amaster, name, termp, winp)
	int *amaster;
	char *name;
	struct termios *termp;
	struct winsize *winp;
{
	int master, slave, pid;

	if (openpty(&master, &slave, name, termp, winp) == -1)
		return (-1);
	switch (pid = fork()) {
	case -1:
		return (-1);
	case 0:
		/* 
		 * child
		 */
		(void) close(master);
		/*
		 * 4300297: login_tty() may fail to set the controlling tty.
		 * Since we have already forked, the best we can do is to 
		 * dup the slave as if login_tty() succeeded.
		 */
		if (login_tty(slave) < 0) {
			syslog(LOG_ERR, "forkpty: login_tty could't make controlling tty");
			(void) dup2(slave, 0);
			(void) dup2(slave, 1);
			(void) dup2(slave, 2);
			if (slave > 2)
				(void) close(slave);
		}
		return (0);
	}
	/*
	 * parent
	 */
	*amaster = master;
	(void) close(slave);
	return (pid);
}