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  * 4. 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
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)pty.c       8.3 (Berkeley) 5/16/94";
  36 #endif
  37 #endif /* LIBC_SCCS and not lint */
  38
  39 #include <sys/types.h>
  40 #include <sys/ioctl.h>
  41 #include <sys/stat.h>
  42
  43 #include <errno.h>
  44 #include <fcntl.h>
  45 #include <grp.h>
  46 #include <libutil.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <termios.h>
  50 #include <unistd.h>
  51
  52 int
  53 openpty(int *amaster, int *aslave, char *name, struct termios *termp,
  54     struct winsize *winp)
  55 {
  56         const char *slavename;
  57         int master, slave;
  58
  59         master = posix_openpt(O_RDWR|O_NOCTTY);
  60         if (master == -1)
  61                 return (-1);
  62
  63         if (grantpt(master) == -1)
  64                 goto bad;
  65
  66         if (unlockpt(master) == -1)
  67                 goto bad;
  68
  69         slavename = ptsname(master);
  70         if (slavename == NULL)
  71                 goto bad;
  72
  73         slave = open(slavename, O_RDWR);
  74         if (slave == -1)
  75                 goto bad;
  76
  77         *amaster = master;
  78         *aslave = slave;
  79
  80         if (name)
  81                 strcpy(name, slavename);
  82         if (termp)
  83                 tcsetattr(slave, TCSAFLUSH, termp);
  84         if (winp)
  85                 ioctl(slave, TIOCSWINSZ, (char *)winp);
  86
  87         return (0);
  88
  89 bad:    close(master);
  90         return (-1);
  91 }
  92
  93 int
  94 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
  95 {
  96         int master, slave, pid;
  97
  98         if (openpty(&master, &slave, name, termp, winp) == -1)
  99                 return (-1);
 100         switch (pid = fork()) {
 101         case -1:
 102                 return (-1);
 103         case 0:
 104                 /*
 105                  * child
 106                  */
 107                 (void) close(master);
 108                 login_tty(slave);
 109                 return (0);
 110         }
 111         /*
 112          * parent
 113          */
 114         *amaster = master;
 115         (void) close(slave);
 116         return (pid);
 117 }