BSD 4_4_Lite2 release

[unix-history] / usr / src / lib / libutil / pty.c

/*-
* 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)
static char sccsid[] = "@(#)pty.c       8.3 (Berkeley) 5/16/94";
#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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

openpty(amaster, aslave, name, termp, winp)
       int *amaster, *aslave;
       char *name;
       struct termios *termp;
       struct winsize *winp;
{
       static 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 = "pqrs"; *cp1; cp1++) {
               line[8] = *cp1;
               for (cp2 = "0123456789abcdef"; *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);
}

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);
}