sysdeps/unix/sysv/linux/getpt.c

   1 /* Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <paths.h>
  25 #include <sys/statfs.h>
  26
  27 #include "linux_fsinfo.h"
  28
  29 /* Path to the master pseudo terminal cloning device.  */
  30 #define _PATH_DEVPTMX _PATH_DEV "ptmx"
  31 /* Directory containing the UNIX98 pseudo terminals.  */
  32 #define _PATH_DEVPTS _PATH_DEV "pts"
  33
  34 /* Prototype for function that opens BSD-style master pseudo-terminals.  */
  35 int __bsd_getpt (void);
  36
  37 /* Open a master pseudo terminal and return its file descriptor.  */
  38 int
  39 __posix_openpt (oflag)
  40      int oflag;
  41 {
  42   static int have_no_dev_ptmx;
  43   int fd;
  44
  45   if (!have_no_dev_ptmx)
  46     {
  47       fd = __open (_PATH_DEVPTMX, oflag);
  48       if (fd != -1)
  49         {
  50           struct statfs fsbuf;
  51           static int devpts_mounted;
  52
  53           /* Check that the /dev/pts filesystem is mounted
  54              or if /dev is a devfs filesystem (this implies /dev/pts).  */
  55           if (devpts_mounted
  56               || (__statfs (_PATH_DEVPTS, &fsbuf) == 0
  57                   && fsbuf.f_type == DEVPTS_SUPER_MAGIC)
  58               || (__statfs (_PATH_DEV, &fsbuf) == 0
  59                   && fsbuf.f_type == DEVFS_SUPER_MAGIC))
  60             {
  61               /* Everything is ok.  */
  62               devpts_mounted = 1;
  63               return fd;
  64             }
  65
  66           /* If /dev/pts is not mounted then the UNIX98 pseudo terminals
  67              are not usable.  */
  68           __close (fd);
  69           have_no_dev_ptmx = 1;
  70         }
  71       else
  72         {
  73           if (errno == ENOENT || errno == ENODEV)
  74             have_no_dev_ptmx = 1;
  75           else
  76             return -1;
  77         }
  78     }
  79
  80   return -1;
  81 }
  82 weak_alias (__posix_openpt, posix_openpt)
  83
  84
  85 int
  86 __getpt (void)
  87 {
  88   int fd = __posix_openpt (O_RDWR);
  89   if (fd == -1)
  90     fd = __bsd_getpt ();
  91   return fd;
  92 }
  93
  94
  95 #define PTYNAME1 "pqrstuvwxyzabcde";
  96 #define PTYNAME2 "0123456789abcdef";
  97
  98 #define __getpt __bsd_getpt
  99 #define HAVE_POSIX_OPENPT
 100 #include <sysdeps/unix/bsd/getpt.c>