sysdeps/generic/pty.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   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
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)pty.c       8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <sys/cdefs.h>
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <fcntl.h>
  43 #include <termios.h>
  44 #include <errno.h>
  45 #include <unistd.h>
  46 #include <stdio.h>
  47 #include <string.h>
  48 #include <grp.h>
  49
  50 int
  51 openpty(amaster, aslave, name, termp, winp)
  52         int *amaster, *aslave;
  53         char *name;
  54         struct termios *termp;
  55         struct winsize *winp;
  56 {
  57         static char line[] = "/dev/ptyXX";
  58         register const char *cp1, *cp2;
  59         register int master, slave, ttygid;
  60         struct group *gr;
  61
  62         if ((gr = getgrnam("tty")) != NULL)
  63                 ttygid = gr->gr_gid;
  64         else
  65                 ttygid = -1;
  66
  67         for (cp1 = "pqrs"; *cp1; cp1++) {
  68                 line[8] = *cp1;
  69                 for (cp2 = "0123456789abcdef"; *cp2; cp2++) {
  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                                 line[5] = 'p';
  94                         }
  95                 }
  96         }
  97         errno = ENOENT; /* out of ptys */
  98         return (-1);
  99 }
 100
 101 int
 102 forkpty(amaster, name, termp, winp)
 103         int *amaster;
 104         char *name;
 105         struct termios *termp;
 106         struct winsize *winp;
 107 {
 108         extern int login_tty();
 109         int master, slave, pid;
 110
 111         if (openpty(&master, &slave, name, termp, winp) == -1)
 112                 return (-1);
 113         switch (pid = fork()) {
 114         case -1:
 115                 return (-1);
 116         case 0:
 117                 /*
 118                  * child
 119                  */
 120                 (void) close(master);
 121                 login_tty(slave);
 122                 return (0);
 123         }
 124         /*
 125          * parent
 126          */
 127         *amaster = master;
 128         (void) close(slave);
 129         return (pid);
 130 }