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/*
* Copyright (C) 2008-2009 Red Hat, Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND Red Hat DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL Red Hat BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include <config.h>
#include <isc/mem.h>
#include <isc/mutex.h>
#include <isc/once.h>
#include <isc/result.h>
#include <isc/types.h>
#include <isc/util.h>
#include <dns/dynamic_db.h>
#include <dns/log.h>
#include <dns/types.h>
#if HAVE_DLFCN_H
#include <dlfcn.h>
#endif
#define CHECK(op) \
do { result = (op); \
if (result != ISC_R_SUCCESS) goto cleanup; \
} while (0)
typedef isc_result_t (*register_func_t)(isc_mem_t *mctx, const char *name,
const char * const *argv, dns_view_t *view,
dns_zonemgr_t *zmgr);
typedef void (*destroy_func_t)(void);
typedef struct dyndb_implementation dyndb_implementation_t;
struct dyndb_implementation {
isc_mem_t *mctx;
void *handle;
register_func_t register_function;
destroy_func_t destroy_function;
LINK(dyndb_implementation_t) link;
};
/* List of implementations. Locked by dyndb_lock. */
static LIST(dyndb_implementation_t) dyndb_implementations;
/* Locks dyndb_implementations. */
static isc_mutex_t dyndb_lock;
static isc_once_t once = ISC_ONCE_INIT;
static void
dyndb_initialize(void) {
RUNTIME_CHECK(isc_mutex_init(&dyndb_lock) == ISC_R_SUCCESS);
INIT_LIST(dyndb_implementations);
}
#if HAVE_DLFCN_H
static isc_result_t
load_symbol(void *handle, const char *symbol_name, void **symbolp)
{
const char *errmsg;
void *symbol;
REQUIRE(handle != NULL);
REQUIRE(symbolp != NULL && *symbolp == NULL);
symbol = dlsym(handle, symbol_name);
if (symbol == NULL) {
errmsg = dlerror();
if (errmsg == NULL)
errmsg = "returned function pointer is NULL";
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
"failed to lookup symbol %s: %s",
symbol_name, errmsg);
return ISC_R_FAILURE;
}
dlerror();
*symbolp = symbol;
return ISC_R_SUCCESS;
}
static isc_result_t
load_library(isc_mem_t *mctx, const char *filename, dyndb_implementation_t **impp)
{
isc_result_t result;
void *handle;
dyndb_implementation_t *imp;
register_func_t register_function = NULL;
destroy_func_t destroy_function = NULL;
REQUIRE(impp != NULL && *impp == NULL);
handle = dlopen(filename, RTLD_LAZY);
if (handle == NULL) {
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
"failed to dynamically load driver '%s': %s",
filename, dlerror());
result = ISC_R_FAILURE;
goto cleanup;
}
dlerror();
CHECK(load_symbol(handle, "dynamic_driver_init",
(void **)®ister_function));
CHECK(load_symbol(handle, "dynamic_driver_destroy",
(void **)&destroy_function));
imp = isc_mem_get(mctx, sizeof(dyndb_implementation_t));
if (imp == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup;
}
imp->mctx = NULL;
isc_mem_attach(mctx, &imp->mctx);
imp->handle = handle;
imp->register_function = register_function;
imp->destroy_function = destroy_function;
INIT_LINK(imp, link);
*impp = imp;
return ISC_R_SUCCESS;
cleanup:
if (handle != NULL)
dlclose(handle);
return result;
}
static void
unload_library(dyndb_implementation_t **impp)
{
dyndb_implementation_t *imp;
REQUIRE(impp != NULL && *impp != NULL);
imp = *impp;
isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));
*impp = NULL;
}
#else /* HAVE_DLFCN_H */
static isc_result_t
load_library(isc_mem_t *mctx, const char *filename, dyndb_implementation_t **impp)
{
UNUSED(mctx);
UNUSED(filename);
UNUSED(impp);
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DYNDB,
ISC_LOG_ERROR,
"dynamic database support is not implemented")
return ISC_R_NOTIMPLEMENTED;
}
static void
unload_library(dyndb_implementation_t **impp)
{
dyndb_implementation_t *imp;
REQUIRE(impp != NULL && *impp != NULL);
imp = *impp;
isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));
*impp = NULL;
}
#endif /* HAVE_DLFCN_H */
isc_result_t
dns_dynamic_db_load(const char *libname, const char *name, isc_mem_t *mctx,
const char * const *argv, dns_view_t *view,
dns_zonemgr_t *zmgr)
{
isc_result_t result;
dyndb_implementation_t *implementation = NULL;
RUNTIME_CHECK(isc_once_do(&once, dyndb_initialize) == ISC_R_SUCCESS);
CHECK(load_library(mctx, libname, &implementation));
CHECK(implementation->register_function(mctx, name, argv, view, zmgr));
LOCK(&dyndb_lock);
APPEND(dyndb_implementations, implementation, link);
UNLOCK(&dyndb_lock);
return ISC_R_SUCCESS;
cleanup:
if (implementation != NULL)
unload_library(&implementation);
return result;
}
void
dns_dynamic_db_cleanup(void)
{
dyndb_implementation_t *elem;
dyndb_implementation_t *next;
RUNTIME_CHECK(isc_once_do(&once, dyndb_initialize) == ISC_R_SUCCESS);
LOCK(&dyndb_lock);
elem = HEAD(dyndb_implementations);
while (elem != NULL) {
next = NEXT(elem, link);
UNLINK(dyndb_implementations, elem, link);
elem->destroy_function();
unload_library(&elem);
elem = next;
}
UNLOCK(&dyndb_lock);
isc_mutex_destroy(&dyndb_lock);
}
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