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lvm2/lib/locking/external_locking.c
Alasdair Kergon d1d9800ef1 Refactoring.
2002-11-18 14:01:16 +00:00

77 lines
1.7 KiB
C

/*
* Copyright (C) 2002 Sistina Software (UK) Limited.
*
* This file is released under the LGPL.
*
*/
#include "lib.h"
#include "locking_types.h"
#include "defaults.h"
#include "sharedlib.h"
#include <dlfcn.h>
static void *_locking_lib = NULL;
static void (*_end_fn) (void) = NULL;
static int (*_lock_fn) (struct cmd_context * cmd, const char *resource,
int flags) = NULL;
static int (*_init_fn) (int type, struct config_tree * cf) = NULL;
static int _lock_resource(struct cmd_context *cmd, const char *resource,
int flags)
{
if (_lock_fn)
return _lock_fn(cmd, resource, flags);
else
return 0;
}
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;
}
int init_external_locking(struct locking_type *locking, struct config_tree *cf)
{
const char *libname;
if (_locking_lib) {
log_error("External locking already initialised");
return 1;
}
locking->lock_resource = _lock_resource;
locking->fin_locking = _fin_external_locking;
libname = find_config_str(cf->root, "global/locking_library", '/',
DEFAULT_LOCKING_LIB);
if (!(_locking_lib = load_shared_library(cf, libname, "locking"))) {
stack;
return 0;
}
/* Get the functions we need */
if (!(_init_fn = dlsym(_locking_lib, "init_locking")) ||
!(_lock_fn = dlsym(_locking_lib, "lock_resource")) ||
!(_end_fn = dlsym(_locking_lib, "end_locking"))) {
log_error("Shared library %s does not contain locking "
"functions", libname);
dlclose(_locking_lib);
_locking_lib = NULL;
return 0;
}
log_verbose("Loaded external locking library %s", libname);
return _init_fn(2, cf);
}