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lvm2/lib/locking/file_locking.c
David Teigland 6e6ef95ba6 Implement lock-override options without locking type
The options: --nolocking, --readonly, --sysinit
override, or make exceptions to, the normal file locking
behavior.  Implement these by just checking for the
options in the file locking path instead of using
special locking types.
2018-06-07 16:17:04 +01:00

117 lines
2.9 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2014 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "lib/misc/lib.h"
#include "lib/locking/locking.h"
#include "locking_types.h"
#include "lib/activate/activate.h"
#include "lib/config/config.h"
#include "lib/config/defaults.h"
#include "lib/misc/lvm-string.h"
#include "lib/misc/lvm-flock.h"
#include <limits.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
static char _lock_dir[PATH_MAX];
static void _fin_file_locking(void)
{
release_flocks(1);
}
static void _reset_file_locking(void)
{
release_flocks(0);
}
static int _file_lock_resource(struct cmd_context *cmd, const char *resource,
uint32_t flags, const struct logical_volume *lv)
{
char lockfile[PATH_MAX];
switch (flags & LCK_SCOPE_MASK) {
case LCK_VG:
if (!strcmp(resource, VG_SYNC_NAMES))
fs_unlock();
/* LCK_CACHE does not require a real lock */
if (flags & LCK_CACHE)
break;
if (is_orphan_vg(resource) || is_global_vg(resource)) {
if (dm_snprintf(lockfile, sizeof(lockfile),
"%s/P_%s", _lock_dir, resource + 1) < 0) {
log_error("Too long locking filename %s/P_%s.",
_lock_dir, resource + 1);
return 0;
}
} else
if (dm_snprintf(lockfile, sizeof(lockfile),
"%s/V_%s", _lock_dir, resource) < 0) {
log_error("Too long locking filename %s/V_%s.",
_lock_dir, resource);
return 0;
}
if (!lock_file(lockfile, flags))
return_0;
break;
default:
log_error("Unrecognised lock scope: %d",
flags & LCK_SCOPE_MASK);
return 0;
}
return 1;
}
int init_file_locking(struct locking_type *locking, struct cmd_context *cmd,
int suppress_messages)
{
int r;
const char *locking_dir;
init_flock(cmd);
locking->lock_resource = _file_lock_resource;
locking->reset_locking = _reset_file_locking;
locking->fin_locking = _fin_file_locking;
locking->flags = LCK_FLOCK;
/* Get lockfile directory from config file */
locking_dir = find_config_tree_str(cmd, global_locking_dir_CFG, NULL);
if (!dm_strncpy(_lock_dir, locking_dir, sizeof(_lock_dir))) {
log_error("Path for locking_dir %s is invalid.", locking_dir);
return 0;
}
(void) dm_prepare_selinux_context(_lock_dir, S_IFDIR);
r = dm_create_dir(_lock_dir);
(void) dm_prepare_selinux_context(NULL, 0);
if (!r)
return 0;
/* Trap a read-only file system */
if ((access(_lock_dir, R_OK | W_OK | X_OK) == -1) && (errno == EROFS))
return 0;
return 1;
}