1/* Determine directory for shm/sem files. Generic POSIX version.
2 Copyright (C) 2014-2023 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 <unistd.h>
20
21#if _POSIX_MAPPED_FILES
22
23#include <alloc_buffer.h>
24#include <shm-directory.h>
25#include <string.h>
26#include <sys/mman.h>
27#include <fcntl.h>
28#include <errno.h>
29
30int
31__shm_get_name (struct shmdir_name *result, const char *name, bool sem_prefix)
32{
33 struct alloc_buffer buffer;
34 size_t namelen;
35
36 buffer = alloc_buffer_create (result->name, sizeof (result->name));
37 alloc_buffer_copy_bytes (&buffer, SHMDIR, strlen (SHMDIR));
38
39#if defined (SHM_ANON) && defined (O_TMPFILE)
40 if (name == SHM_ANON)
41 {
42 /* For SHM_ANON, we want shm_open () to pass O_TMPFILE to open (),
43 with SHMDIR itself as the path. So, leave it at that. */
44 alloc_buffer_add_byte (&buffer, 0);
45 if (alloc_buffer_has_failed (&buffer))
46 return -1;
47 return 0;
48 }
49#endif
50
51 while (name[0] == '/')
52 ++name;
53 namelen = strlen (name);
54
55 if (sem_prefix)
56 alloc_buffer_copy_bytes (&buffer, "sem.", strlen ("sem."));
57 alloc_buffer_copy_bytes (&buffer, name, namelen + 1);
58 if (namelen == 0 || memchr (name, '/', namelen) != NULL)
59 return EINVAL;
60 if (alloc_buffer_has_failed (&buffer))
61 {
62 if (namelen > NAME_MAX)
63 return ENAMETOOLONG;
64 return EINVAL;
65 }
66 return 0;
67}
68libc_hidden_def (__shm_get_name)
69
70#endif
71