util/pty.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993, 1994
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55
  56 #include <sys/types.h>
  57 #include <sys/ioctl.h>
  58 #include <sys/stat.h>
  59
  60 #include <errno.h>
  61 #include <fcntl.h>
  62 #include <grp.h>
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #include <termios.h>
  67 #include <unistd.h>
  68
  69 int openpty(amaster, aslave, name, termp, winp)
  70         int *amaster, *aslave;
  71         char *name;
  72         struct termios *termp;
  73         struct winsize *winp;
  74 {
  75         static char line[] = "/dev/ptyXX";
  76         register const char *cp1, *cp2;
  77         register int master, slave, ttygid;
  78         struct group *gr;
  79
  80         if ((gr = getgrnam("tty")) != NULL)
  81                 ttygid = gr->gr_gid;
  82         else
  83                 ttygid = -1;
  84
  85         for (cp1 = "pqrstuvwxy"; *cp1; cp1++) {
  86                 line[8] = *cp1;
  87                 for (cp2 = "0123456789abcdef"; *cp2; cp2++) {
  88                         line[5] = 'p';
  89                         line[9] = *cp2;
  90                         if ((master = open(line, O_RDWR, 0)) == -1) {
  91                                 if (errno == ENOENT)
  92                                         return (-1);    /* out of ptys */
  93                         } else {
  94                                 line[5] = 't';
  95                                 (void) chown(line, getuid(), ttygid);
  96                                 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP);
  97                                 (void) revoke(line);
  98                                 if ((slave = open(line, O_RDWR, 0)) != -1) {
  99                                         *amaster = master;
 100                                         *aslave = slave;
 101                                         if (name)
 102                                                 strcpy(name, line);
 103                                         if (termp)
 104                                                 (void) tcsetattr(slave,
 105                                                         TCSAFLUSH, termp);
 106                                         if (winp)
 107                                                 (void) ioctl(slave, TIOCSWINSZ,
 108                                                         (char *)winp);
 109                                         return (0);
 110                                 }
 111                                 (void) close(master);
 112                         }
 113                 }
 114         }
 115         errno = ENOENT; /* out of ptys */
 116         return (-1);
 117 }
 118
 119 forkpty(amaster, name, termp, winp)
 120         int *amaster;
 121         char *name;
 122         struct termios *termp;
 123         struct winsize *winp;
 124 {
 125         int master, slave, pid;
 126
 127         if (openpty(&master, &slave, name, termp, winp) == -1)
 128                 return (-1);
 129         switch (pid = fork()) {
 130         case -1:
 131                 return (-1);
 132         case 0:
 133                 /*
 134                  * child
 135                  */
 136                 (void) close(master);
 137                 login_tty(slave);
 138                 return (0);
 139         }
 140         /*
 141          * parent
 142          */
 143         *amaster = master;
 144         (void) close(slave);
 145         return (pid);
 146 }