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/* Determine directory for shm/sem files. GNU/kFreeBSD version.
Copyright (C) 2000-2015 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
<http://www.gnu.org/licenses/>. */
#include "shm-directory.h"
#include <errno.h>
#include <mntent.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <sys/statfs.h>
#include <libc-lock.h>
/* Mount point of the shared memory filesystem. */
static struct
{
char *dir;
size_t dirlen;
} mountpoint;
/* This is the default directory. */
static const char defaultdir[] = "/dev/shm/";
/* This is the alternate debian directory. */
static const char alternatedir[] = "/run/shm";
/* Protect the `mountpoint' variable above. */
__libc_once_define (static, once);
/* Determine where the shmfs is mounted (if at all). */
static void
where_is_shmfs (void)
{
struct statfs f;
/* The canonical place is /dev/shm. This is at least what the
documentation tells everybody to do. */
if (__statfs (defaultdir, &f) == 0)
{
/* It is in the normal place. */
mountpoint.dir = (char *) defaultdir;
mountpoint.dirlen = sizeof (defaultdir) - 1;
return;
}
/* The alternate place is /run/shm. */
if (__statfs (alternatedir, &f) == 0)
{
/* It is in the normal place. */
mountpoint.dir = (char *) alternatedir;
mountpoint.dirlen = sizeof (alternatedir) - 1;
return;
}
}
const char *
__shm_directory (size_t *len)
{
/* Determine where the shmfs is mounted. */
__libc_once (once, where_is_shmfs);
/* If we don't know the mount points there is nothing we can do. Ever. */
if (__glibc_unlikely (mountpoint.dir == NULL))
{
__set_errno (ENOSYS);
return NULL;
}
*len = mountpoint.dirlen;
return mountpoint.dir;
}
#if IS_IN (libpthread)
hidden_def (__shm_directory)
#endif
/* Make sure the table is freed if we want to free everything before
exiting. */
libc_freeres_fn (freeit)
{
if (mountpoint.dir != defaultdir)
free (mountpoint.dir);
}
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