sysdeps/unix/sysv/linux/grantpt.c

   1 /* Copyright (C) 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <limits.h>
  20 #include <stdlib.h>
  21 #include <sys/statfs.h>
  22
  23 /* Constant that identifies the `devpts' filesystem.  */
  24 #define DEVPTS_SUPER_MAGIC      0x1cd1
  25
  26 /* Prototype for function that changes ownership and access permission
  27    for slave pseudo terminals that do not live on a `devpts'
  28    filesystem.  */
  29 int __unix_grantpt (int fd);
  30
  31 /* Prototype for private function that gets the name of the slave
  32    pseudo terminal in a safe way.  */
  33 static int pts_name (int fd, char **pts, size_t buf_len);
  34
  35 /* Change the ownership and access permission of the slave pseudo
  36    terminal associated with the master pseudo terminal specified
  37    by FD.  */
  38 int
  39 grantpt (int fd)
  40 {
  41   struct statfs fsbuf;
  42 #ifdef PATH_MAX
  43   char _buf[PATH_MAX];
  44 #else
  45   char _buf[512];
  46 #endif
  47   char *buf = _buf;
  48
  49   if (pts_name (fd, &buf, sizeof (_buf)))
  50     return -1;
  51
  52   if (__statfs (buf, &fsbuf) < 0)
  53     return -1;
  54
  55   /* If the slave pseudo terminal lives on a `devpts' filesystem, the
  56      ownership and access permission are already set.  */
  57   if (fsbuf.f_type == DEVPTS_SUPER_MAGIC)
  58     return 0;
  59
  60   return __unix_grantpt (fd);
  61 }
  62
  63 #define grantpt __unix_grantpt
  64 #include <sysdeps/unix/grantpt.c>