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 #include <pty.h>
  50 #include <utmp.h>
  51
  52 #ifndef REVOKE
  53 # define REVOKE(Line) revoke (Line)
  54 #endif
  55
  56 int
  57 openpty(amaster, aslave, name, termp, winp)
  58         int *amaster, *aslave;
  59         char *name;
  60         struct termios *termp;
  61         struct winsize *winp;
  62 {
  63         char line[11];
  64         register const char *cp1, *cp2;
  65         register int master, slave, ttygid;
  66         size_t buflen = sysconf (_SC_GETGR_R_SIZE_MAX);
  67         char buffer[buflen];
  68         struct group grbuffer;
  69         struct group *gr;
  70
  71         strcpy (line, "/dev/ptyXX");
  72
  73         if (getgrnam_r("tty", &grbuffer, buffer, buflen, &gr) >= 0)
  74                 ttygid = gr->gr_gid;
  75         else
  76                 ttygid = -1;
  77
  78         for (cp1 = "pqrs"; *cp1; cp1++) {
  79                 line[8] = *cp1;
  80                 for (cp2 = "0123456789abcdef"; *cp2; cp2++) {
  81                         line[9] = *cp2;
  82                         if ((master = open(line, O_RDWR, 0)) == -1) {
  83                                 if (errno == ENOENT)
  84                                         return (-1);    /* out of ptys */
  85                         } else {
  86                                 line[5] = 't';
  87                                 (void) chown(line, getuid(), ttygid);
  88                                 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP);
  89                                 REVOKE(line);
  90                                 if ((slave = open(line, O_RDWR, 0)) != -1) {
  91                                         *amaster = master;
  92                                         *aslave = slave;
  93                                         if (name)
  94                                                 strcpy(name, line);
  95                                         if (termp)
  96                                                 (void) tcsetattr(slave,
  97                                                         TCSAFLUSH, termp);
  98                                         if (winp)
  99                                                 (void) ioctl(slave, TIOCSWINSZ,
 100                                                         (char *)winp);
 101                                         return (0);
 102                                 }
 103                                 (void) close(master);
 104                                 line[5] = 'p';
 105                         }
 106                 }
 107         }
 108         __set_errno (ENOENT);   /* out of ptys */
 109         return (-1);
 110 }
 111
 112 int
 113 forkpty(amaster, name, termp, winp)
 114         int *amaster;
 115         char *name;
 116         struct termios *termp;
 117         struct winsize *winp;
 118 {
 119         int master, slave, pid;
 120
 121         if (openpty(&master, &slave, name, termp, winp) == -1)
 122                 return (-1);
 123         switch (pid = fork()) {
 124         case -1:
 125                 return (-1);
 126         case 0:
 127                 /*
 128                  * child
 129                  */
 130                 (void) close(master);
 131                 login_tty(slave);
 132                 return (0);
 133         }
 134         /*
 135          * parent
 136          */
 137         *amaster = master;
 138         (void) close(slave);
 139         return (pid);
 140 }