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mirror of git://sourceware.org/git/lvm2.git synced 2024-10-28 03:27:58 +03:00
lvm2/lib/locking/external_locking.c
Zdenek Kabelac 84cdf85bd2 cleanup: constify activation usage of lv pointer
Let's enforce cheking of write access to LV by compiler.
Activation part does never need to write anything to LV
so keep LV pointer const.
2014-09-24 10:54:47 +02:00

107 lines
3.0 KiB
C

/*
* Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2006 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "locking_types.h"
#include "defaults.h"
#include "sharedlib.h"
#include "toolcontext.h"
#include "activate.h"
static void *_locking_lib = NULL;
static void (*_reset_fn) (void) = NULL;
static void (*_end_fn) (void) = NULL;
static int (*_lock_fn) (struct cmd_context * cmd, const char *resource,
uint32_t flags) = NULL;
static int (*_init_fn) (int type, struct dm_config_tree * cft,
uint32_t *flags) = NULL;
static int (*_lock_query_fn) (const char *resource, int *mode) = NULL;
static int _lock_resource(struct cmd_context *cmd, const char *resource,
uint32_t flags, const struct logical_volume *lv __attribute__((unused)))
{
if (!_lock_fn)
return 0;
if (!strcmp(resource, VG_SYNC_NAMES)) {
/* Hide this lock request from external locking */
fs_unlock();
return 1;
}
return _lock_fn(cmd, resource, flags);
}
static void _fin_external_locking(void)
{
if (_end_fn)
_end_fn();
dlclose(_locking_lib);
_locking_lib = NULL;
_init_fn = NULL;
_end_fn = NULL;
_lock_fn = NULL;
_reset_fn = NULL;
}
static void _reset_external_locking(void)
{
if (_reset_fn)
_reset_fn();
}
int init_external_locking(struct locking_type *locking, struct cmd_context *cmd,
int suppress_messages)
{
const char *libname;
if (_locking_lib) {
log_error_suppress(suppress_messages, "External locking already initialised");
return 1;
}
locking->lock_resource = _lock_resource;
locking->fin_locking = _fin_external_locking;
locking->reset_locking = _reset_external_locking;
locking->flags = 0;
if (!(libname = find_config_tree_str(cmd, global_locking_library_CFG, NULL)))
return_0;
if (!(_locking_lib = load_shared_library(cmd, libname, "locking", 1)))
return_0;
/* Get the functions we need */
if (!(_init_fn = dlsym(_locking_lib, "locking_init")) ||
!(_lock_fn = dlsym(_locking_lib, "lock_resource")) ||
!(_reset_fn = dlsym(_locking_lib, "reset_locking")) ||
!(_end_fn = dlsym(_locking_lib, "locking_end"))) {
log_error_suppress(suppress_messages, "Shared library %s does "
"not contain locking functions", libname);
dlclose(_locking_lib);
_locking_lib = NULL;
return 0;
}
if (!(_lock_query_fn = dlsym(_locking_lib, "query_resource")))
log_warn_suppress(suppress_messages, "WARNING: %s: _query_resource() "
"missing: Using inferior activation method.", libname);
log_verbose("Loaded external locking library %s", libname);
return _init_fn(2, cmd->cft, &locking->flags);
}