glibc/posix/shm-directory.c

71 lines
2.1 KiB
C

/* Determine directory for shm/sem files. Generic POSIX version.
Copyright (C) 2014-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <unistd.h>
#if _POSIX_MAPPED_FILES
#include <alloc_buffer.h>
#include <shm-directory.h>
#include <string.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <errno.h>
int
__shm_get_name (struct shmdir_name *result, const char *name, bool sem_prefix)
{
struct alloc_buffer buffer;
size_t namelen;
buffer = alloc_buffer_create (result->name, sizeof (result->name));
alloc_buffer_copy_bytes (&buffer, SHMDIR, strlen (SHMDIR));
#if defined (SHM_ANON) && defined (O_TMPFILE)
if (name == SHM_ANON)
{
/* For SHM_ANON, we want shm_open () to pass O_TMPFILE to open (),
with SHMDIR itself as the path. So, leave it at that. */
alloc_buffer_add_byte (&buffer, 0);
if (alloc_buffer_has_failed (&buffer))
return -1;
return 0;
}
#endif
while (name[0] == '/')
++name;
namelen = strlen (name);
if (sem_prefix)
alloc_buffer_copy_bytes (&buffer, "sem.", strlen ("sem."));
alloc_buffer_copy_bytes (&buffer, name, namelen + 1);
if (namelen == 0 || memchr (name, '/', namelen) != NULL)
return EINVAL;
if (alloc_buffer_has_failed (&buffer))
{
if (namelen > NAME_MAX)
return ENAMETOOLONG;
return EINVAL;
}
return 0;
}
libc_hidden_def (__shm_get_name)
#endif