1 /* Utilities for reading/writing fstab, mtab, etc.
2 Copyright (C) 1995-2022 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
23 struct mntent_buffer
24 {
25 struct mntent m;
26 char buffer[4096];
27 };
28
29 /* We don't want to allocate the static buffer all the time since it
30 is not always used (in fact, rather infrequently). */
31 libc_freeres_ptr (static void *mntent_buffer);
32
33 static void *
allocate(void * closure)34 allocate (void *closure)
35 {
36 return malloc (sizeof (struct mntent_buffer));
37 }
38
39 static void
deallocate(void * closure,void * ptr)40 deallocate (void *closure, void *ptr)
41 {
42 free (ptr);
43 }
44
45 struct mntent *
getmntent(FILE * stream)46 getmntent (FILE *stream)
47 {
48 struct mntent_buffer *buffer = allocate_once (&mntent_buffer,
49 allocate, deallocate, NULL);
50 if (buffer == NULL)
51 /* If no core is available we don't have a chance to run the
52 program successfully and so returning NULL is an acceptable
53 result. */
54 return NULL;
55
56 return __getmntent_r (stream, &buffer->m,
57 buffer->buffer, sizeof (buffer->buffer));
58 }
59