misc/mntent.c

   1 /* Utilities for reading/writing fstab, mtab, etc.
   2    Copyright (C) 1995-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <mntent.h>
  20 #include <stdlib.h>
  21 #include <allocate_once.h>
  22 #include <set-freeres.h>
  23
  24 struct mntent_buffer
  25 {
  26   struct mntent m;
  27   char buffer[4096];
  28 };
  29
  30 /* We don't want to allocate the static buffer all the time since it
  31    is not always used (in fact, rather infrequently).  */
  32 static void *mntent_buffer;
  33
  34 static void *
  35 allocate (void *closure)
  36 {
  37   return malloc (sizeof (struct mntent_buffer));
  38 }
  39
  40 static void
  41 deallocate (void *closure, void *ptr)
  42 {
  43   free (ptr);
  44 }
  45
  46 struct mntent *
  47 getmntent (FILE *stream)
  48 {
  49   struct mntent_buffer *buffer = allocate_once (&mntent_buffer,
  50                                                 allocate, deallocate, NULL);
  51   if (buffer == NULL)
  52     /* If no core is available we don't have a chance to run the
  53        program successfully and so returning NULL is an acceptable
  54        result.  */
  55     return NULL;
  56
  57   return __getmntent_r (stream, &buffer->m,
  58                         buffer->buffer, sizeof (buffer->buffer));
  59 }
  60
  61 weak_alias (mntent_buffer, __libc_mntent_freemem_ptr)