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/*
* 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"
#include "locking.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)
{
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;
libname = find_config_tree_str(cmd, "global/locking_library",
DEFAULT_LOCKING_LIB);
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);
}
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