util/pty.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1990, 1993, 1994
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <sys/types.h>
  60 #include <sys/ioctl.h>
  61 #include <sys/stat.h>
  62
  63 #include <errno.h>
  64 #include <fcntl.h>
  65 #include <grp.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #include <termios.h>
  70 #include <unistd.h>
  71
  72 int openpty(amaster, aslave, name, termp, winp)
  73         int *amaster, *aslave;
  74         char *name;
  75         struct termios *termp;
  76         struct winsize *winp;
  77 {
  78         static char line[] = "/dev/ptyXX";
  79         register const char *cp1, *cp2;
  80         register int master, slave, ttygid;
  81         struct group *gr;
  82
  83         if ((gr = getgrnam("tty")) != NULL)
  84                 ttygid = gr->gr_gid;
  85         else
  86                 ttygid = -1;
  87
  88         for (cp1 = "pqrstuvwxy"; *cp1; cp1++) {
  89                 line[8] = *cp1;
  90                 for (cp2 = "0123456789abcdef"; *cp2; cp2++) {
  91                         line[5] = 'p';
  92                         line[9] = *cp2;
  93                         if ((master = open(line, O_RDWR, 0)) == -1) {
  94                                 if (errno == ENOENT)
  95                                         return (-1);    /* out of ptys */
  96                         } else {
  97                                 line[5] = 't';
  98                                 (void) chown(line, getuid(), ttygid);
  99                                 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP);
 100                                 (void) revoke(line);
 101                                 if ((slave = open(line, O_RDWR, 0)) != -1) {
 102                                         *amaster = master;
 103                                         *aslave = slave;
 104                                         if (name)
 105                                                 strcpy(name, line);
 106                                         if (termp)
 107                                                 (void) tcsetattr(slave,
 108                                                         TCSAFLUSH, termp);
 109                                         if (winp)
 110                                                 (void) ioctl(slave, TIOCSWINSZ,
 111                                                         (char *)winp);
 112                                         return (0);
 113                                 }
 114                                 (void) close(master);
 115                         }
 116                 }
 117         }
 118         errno = ENOENT; /* out of ptys */
 119         return (-1);
 120 }
 121
 122 forkpty(amaster, name, termp, winp)
 123         int *amaster;
 124         char *name;
 125         struct termios *termp;
 126         struct winsize *winp;
 127 {
 128         int master, slave, pid;
 129
 130         if (openpty(&master, &slave, name, termp, winp) == -1)
 131                 return (-1);
 132         switch (pid = fork()) {
 133         case -1:
 134                 return (-1);
 135         case 0:
 136                 /*
 137                  * child
 138                  */
 139                 (void) close(master);
 140                 login_tty(slave);
 141                 return (0);
 142         }
 143         /*
 144          * parent
 145          */
 146         *amaster = master;
 147         (void) close(slave);
 148         return (pid);
 149 }