util/pty.c

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