lib/libutil/pty.c

   1 /*-
   2  * Copyright (c) 1990, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)pty.c    8.3 (Berkeley) 5/16/94
  34  * $FreeBSD: src/lib/libutil/pty.c,v 1.10 1999/08/28 00:05:51 peter Exp $
  35  * $DragonFly: src/lib/libutil/pty.c,v 1.5 2005/03/04 06:22:57 cpressey Exp $
  36  */
  37
  38 #include <sys/types.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/stat.h>
  41
  42 #include <errno.h>
  43 #include <fcntl.h>
  44 #include <grp.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <termios.h>
  48 #include <unistd.h>
  49
  50 #include "libutil.h"
  51
  52 int
  53 openpty(int *amaster, int *aslave, char *name, struct termios *termp,
  54         struct winsize *winp)
  55 {
  56         char line[] = "/dev/ptyXX";
  57         const char *cp1, *cp2;
  58         int master, slave, ttygid;
  59         struct group *gr;
  60
  61         if ((gr = getgrnam("tty")) != NULL)
  62                 ttygid = gr->gr_gid;
  63         else
  64                 ttygid = -1;
  65
  66         for (cp1 = "pqrsPQRS"; *cp1; cp1++) {
  67                 line[8] = *cp1;
  68                 for (cp2 = "0123456789abcdefghijklmnopqrstuv"; *cp2; cp2++) {
  69                         line[5] = 'p';
  70                         line[9] = *cp2;
  71                         if ((master = open(line, O_RDWR, 0)) == -1) {
  72                                 if (errno == ENOENT)
  73                                         return (-1);    /* out of ptys */
  74                         } else {
  75                                 line[5] = 't';
  76                                 (void) chown(line, getuid(), ttygid);
  77                                 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP);
  78                                 (void) revoke(line);
  79                                 if ((slave = open(line, O_RDWR, 0)) != -1) {
  80                                         *amaster = master;
  81                                         *aslave = slave;
  82                                         if (name)
  83                                                 strcpy(name, line);
  84                                         if (termp)
  85                                                 (void) tcsetattr(slave,
  86                                                         TCSAFLUSH, termp);
  87                                         if (winp)
  88                                                 (void) ioctl(slave, TIOCSWINSZ,
  89                                                         (char *)winp);
  90                                         return (0);
  91                                 }
  92                                 (void) close(master);
  93                         }
  94                 }
  95         }
  96         errno = ENOENT; /* out of ptys */
  97         return (-1);
  98 }
  99
 100 int
 101 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
 102 {
 103         int master, slave, pid;
 104
 105         if (openpty(&master, &slave, name, termp, winp) == -1)
 106                 return (-1);
 107         switch (pid = fork()) {
 108         case -1:
 109                 return (-1);
 110         case 0:
 111                 /*
 112                  * child
 113                  */
 114                 (void) close(master);
 115                 login_tty(slave);
 116                 return (0);
 117         }
 118         /*
 119          * parent
 120          */
 121         *amaster = master;
 122         (void) close(slave);
 123         return (pid);
 124 }