text: /*-
   * 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.
   */
  
  #if defined(LIBC_SCCS) && !defined(lint)
  #if 0
  static char sccsid[] = "@(#)pty.c	8.3 (Berkeley) 5/16/94";
  #else
  static const char rcsid[] =
    "$FreeBSD: src/lib/libutil/pty.c,v 1.10 1999/08/28 00:05:51 peter Exp $";
  #endif
  #endif /* LIBC_SCCS and not lint */
  
  #include <sys/types.h>
  #include <sys/ioctl.h>
  #include <sys/stat.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <grp.h>
  #include <stdlib.h>
  #include <string.h>
  #include <termios.h>
  #include <unistd.h>
  #include <libutil.h>
  
  int
  openpty(amaster, aslave, name, termp, winp)
  	int *amaster, *aslave;
  	char *name;
  	struct termios *termp;
  	struct winsize *winp;
  {
  	char line[] = "/dev/ptyXX";
  	register const char *cp1, *cp2;
  	register int master, slave, ttygid;
  	struct group *gr;
  
  	if ((gr = getgrnam("tty")) != NULL)
  		ttygid = gr->gr_gid;
  	else
  		ttygid = -1;
  
  	for (cp1 = "pqrsPQRS"; *cp1; cp1++) {
  		line[8] = *cp1;
  		for (cp2 = "0123456789abcdefghijklmnopqrstuv"; *cp2; cp2++) {
  			line[5] = 'p';
  			line[9] = *cp2;
  			if ((master = open(line, O_RDWR, 0)) == -1) {
  				if (errno == ENOENT)
  					return (-1);	/* out of ptys */
  			} else {
  				line[5] = 't';
  				(void) chown(line, getuid(), ttygid);
  				(void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP);
  				(void) revoke(line);
  				if ((slave = open(line, O_RDWR, 0)) != -1) {
  					*amaster = master;
  					*aslave = slave;
  					if (name)
  						strcpy(name, line);
  					if (termp)
  						(void) tcsetattr(slave,
  							TCSAFLUSH, termp);
  					if (winp)
  						(void) ioctl(slave, TIOCSWINSZ,
  							(char *)winp);
  					return (0);
  				}
  				(void) close(master);
  			}
  		}
  	}
  	errno = ENOENT;	/* out of ptys */
  	return (-1);
  }
  
  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);
  		login_tty(slave);
  		return (0);
  	}
  	/*
  	 * parent
  	 */
  	*amaster = master;
  	(void) close(slave);
  	return (pid);
  }
  