lib/libutil/pty.c

   1 /*-
   2  * Copyright (c) 1990, 1993, 1994
   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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)pty.c    8.3 (Berkeley) 5/16/94
  30  * $FreeBSD: head/lib/libutil/pty.c 184634 2008-11-04 13:50:50Z des $
  31  */
  32
  33 #include <sys/types.h>
  34 #include <sys/ioctl.h>
  35 #include <sys/stat.h>
  36
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <grp.h>
  40 #include <libutil.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <termios.h>
  44 #include <unistd.h>
  45
  46 int
  47 openpty(int *amaster, int *aslave, char *name, struct termios *termp,
  48         struct winsize *winp)
  49 {
  50         const char *slavename;
  51         int master, slave;
  52
  53         master = posix_openpt(O_RDWR|O_NOCTTY);
  54         if (master == -1)
  55                 return (-1);
  56
  57         if (grantpt(master) == -1)
  58                 goto bad;
  59
  60         if (unlockpt(master) == -1)
  61                 goto bad;
  62
  63         slavename = ptsname(master);
  64         if (slavename == NULL)
  65                 goto bad;
  66
  67         slave = open(slavename, O_RDWR);
  68         if (slave == -1)
  69                 goto bad;
  70
  71         *amaster = master;
  72         *aslave = slave;
  73
  74         if (name)
  75                 strcpy(name, slavename);
  76         if (termp)
  77                 tcsetattr(slave, TCSAFLUSH, termp);
  78         if (winp)
  79                 ioctl(slave, TIOCSWINSZ, (char *)winp);
  80
  81         return (0);
  82
  83 bad:    close(master);
  84         return (-1);
  85 }
  86
  87 int
  88 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
  89 {
  90         int master, slave, pid;
  91
  92         if (openpty(&master, &slave, name, termp, winp) == -1)
  93                 return (-1);
  94         switch (pid = fork()) {
  95         case -1:
  96                 (void) close(slave);
  97                 return (-1);
  98         case 0:
  99                 /*
 100                  * child
 101                  */
 102                 (void) close(master);
 103                 login_tty(slave);
 104                 return (0);
 105         }
 106         /*
 107          * parent
 108          */
 109         *amaster = master;
 110         (void) close(slave);
 111         return (pid);
 112 }