util/pty.c

   1 /*
   2  * Copyright (c) 1999, 2007 Apple 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 #include <syslog.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         int master, slave;
  79         char *sname;
  80
  81         if ((master = posix_openpt(O_RDWR|O_NOCTTY)) < 0)
  82                 return -1;
  83         if (grantpt(master) < 0 || unlockpt(master) < 0
  84             || (sname = ptsname(master)) == NULL
  85             || (slave = open(sname, O_RDWR|O_NOCTTY, 0)) < 0) {
  86                 (void) close(master);
  87                 return -1;
  88         }
  89         *amaster = master;
  90         *aslave = slave;
  91         if (name)
  92                 strcpy(name, sname);
  93         if (termp)
  94                 (void) tcsetattr(slave, TCSAFLUSH, termp);
  95         if (winp)
  96                 (void) ioctl(slave, TIOCSWINSZ, (char *)winp);
  97         return (0);
  98 }
  99
 100 int
 101 forkpty(amaster, name, termp, winp)
 102         int *amaster;
 103         char *name;
 104         struct termios *termp;
 105         struct winsize *winp;
 106 {
 107         int master, slave, pid;
 108
 109         if (openpty(&master, &slave, name, termp, winp) == -1)
 110                 return (-1);
 111         switch (pid = fork()) {
 112         case -1:
 113                 return (-1);
 114         case 0:
 115                 /*
 116                  * child
 117                  */
 118                 (void) close(master);
 119                 /*
 120                  * 4300297: login_tty() may fail to set the controlling tty.
 121                  * Since we have already forked, the best we can do is to
 122                  * dup the slave as if login_tty() succeeded.
 123                  */
 124                 if (login_tty(slave) < 0) {
 125                         syslog(LOG_ERR, "forkpty: login_tty could't make controlling tty");
 126                         (void) dup2(slave, 0);
 127                         (void) dup2(slave, 1);
 128                         (void) dup2(slave, 2);
 129                         if (slave > 2)
 130                                 (void) close(slave);
 131                 }
 132                 return (0);
 133         }
 134         /*
 135          * parent
 136          */
 137         *amaster = master;
 138         (void) close(slave);
 139         return (pid);
 140 }