Sapian
/
asterisk
mirror of http://gerrit.asterisk.org/asterisk
3
0
Fork 0
Code Issues Releases Wiki Activity

res_pjsip_outbound_registration: Fix reload race condition.

Browse Source 
Performing a CLI "module reload" command when there are new pjsip.conf
registration objects defined frequently failed to load them correctly.

What happens is a race condition between res_pjsip pushing its reload into
an asynchronous task processor task and the thread that does the rest of
the reloads when it gets to reloading the res_pjsip_outbound_registration
module.  A similar race condition happens between a reload and the CLI/AMI
show registrations commands.  The reload updates the current_states
container and the CLI/AMI commands call get_registrations() which builds a
new current_states container.

* Made res_pjsip.c reload_module() use ast_sip_push_task_synchronous()
instead of ast_sip_push_task() to eliminate two threads processing config
reloads at the same time.

* Made get_registrations() not replace the global current_states container
so the CLI/AMI show registrations command cannot interfere with reloading.
You could never add/remove objects in the container without the
possibility of the container being replaced out from under you by
get_registrations().

* Added a registration loaded sorcery instance observer to purge any dead
registration objects since get_registrations() cannot do this job anymore.
The struct ast_sorcery_instance_observer callbacks must be used because
the callback happens inline with the load process.  The struct
ast_sorcery_observer callbacks are pushed to a different thread.

* Added some global current_states NULL pointer checks in case the
container disappears because of unload_module().

* Made sorcery's struct ast_sorcery_instance_observer.object_type_loaded
callbacks guaranteed to be called before any struct
ast_sorcery_observer.loaded callbacks will be called.

* Moved the check for non-reloadable objects to before the sorcery
instance loading callbacks happen to short circuit unnecessary work.
Previously with non-reloadable objects, the sorcery instance
loading/loaded callbacks would always happen, the individual wizard
loading/loaded would be prevented, and the non-reloadable type logging
message would be logged for each associated wizard.

ASTERISK-24729 #close
Review: https://reviewboard.asterisk.org/r/4381/
........

Merged revisions 431243 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@431251 65c4cc65-6c06-0410-ace0-fbb531ad65f3
changes/42/42/1
Richard Mudgett 11 years ago
parent c7591ef6bc
commit 69e107b24e
3 changed files with 101 additions and 51 deletions
Show Stats Download Patch File Download Diff File

25
main/sorcery.c
Unescape View File

@ -1176,12 +1176,6 @@ static int sorcery_wizard_load(void *obj, void *arg, int flags)
struct sorcery_load_details *details = arg;
void (*load)(void *data, const struct ast_sorcery *sorcery, const char *type);
if (details->reload && !sorcery_reloadable(details->sorcery, details->type)) {
ast_log(LOG_NOTICE, "Type '%s' is not reloadable, "
"maintaining previous values\n", details->type);
return 0;
}
load = !details->reload ? wizard->wizard->callbacks.load : wizard->wizard->callbacks.reload;
if (load) {
@ -1256,22 +1250,31 @@ static int sorcery_object_load(void *obj, void *arg, int flags)
details->type = type->name;
if (details->reload && !sorcery_reloadable(details->sorcery, details->type)) {
ast_log(LOG_NOTICE, "Type '%s' is not reloadable, maintaining previous values\n",
details->type);
return 0;
}
NOTIFY_INSTANCE_OBSERVERS(details->sorcery->observers, object_type_loading,
details->sorcery->module_name, details->sorcery, type->name, details->reload);
ao2_callback(type->wizards, OBJ_NODATA, sorcery_wizard_load, details);
NOTIFY_INSTANCE_OBSERVERS(details->sorcery->observers, object_type_loaded,
details->sorcery->module_name, details->sorcery, type->name, details->reload);
if (ao2_container_count(type->observers)) {
struct sorcery_observer_invocation *invocation = sorcery_observer_invocation_alloc(type, NULL);
struct sorcery_observer_invocation *invocation;
if (invocation && ast_taskprocessor_push(type->serializer, sorcery_observers_notify_loaded, invocation)) {
invocation = sorcery_observer_invocation_alloc(type, NULL);
if (invocation
&& ast_taskprocessor_push(type->serializer, sorcery_observers_notify_loaded,
invocation)) {
ao2_cleanup(invocation);
}
}
NOTIFY_INSTANCE_OBSERVERS(details->sorcery->observers, object_type_loaded,
details->sorcery->module_name, details->sorcery, type->name, details->reload);
return 0;
}

6
res/res_pjsip.c
Unescape View File

@ -3316,7 +3316,11 @@ static int load_module(void)
static int reload_module(void)
{
if (ast_sip_push_task(NULL, reload_configuration_task, NULL)) {
/*
* We must wait for the reload to complete so multiple
* reloads cannot happen at the same time.
*/
if (ast_sip_push_task_synchronous(NULL, reload_configuration_task, NULL)) {
ast_log(LOG_WARNING, "Failed to reload PJSIP\n");
return -1;
}

121
res/res_pjsip_outbound_registration.c
Unescape View File

@ -361,37 +361,12 @@ static struct sip_outbound_registration_state *get_state(const char *id)
return states ? ao2_find(states, id, OBJ_SEARCH_KEY) : NULL;
}
static int registration_state_add(void *obj, void *arg, int flags)
{
struct sip_outbound_registration_state *state =
get_state(ast_sorcery_object_get_id(obj));
if (state) {
ao2_link(arg, state);
ao2_ref(state, -1);
}
return 0;
}
static struct ao2_container *get_registrations(void)
{
RAII_VAR(struct ao2_container *, new_states, NULL, ao2_cleanup);
struct ao2_container *registrations = ast_sorcery_retrieve_by_fields(
ast_sip_get_sorcery(), "registration",
AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);
if (!(new_states = ao2_container_alloc(DEFAULT_STATE_BUCKETS,
registration_state_hash, registration_state_cmp))) {
ast_log(LOG_ERROR, "Unable to allocate registration states container\n");
return NULL;
}
if (registrations && ao2_container_count(registrations)) {
ao2_callback(registrations, OBJ_NODATA, registration_state_add, new_states);
}
ao2_global_obj_replace_unref(current_states, new_states);
return registrations;
}
@ -1060,11 +1035,16 @@ static int sip_outbound_registration_perform(void *data)
static int sip_outbound_registration_apply(const struct ast_sorcery *sorcery, void *obj)
{
RAII_VAR(struct ao2_container *, states, ao2_global_obj_ref(current_states), ao2_cleanup);
RAII_VAR(struct sip_outbound_registration_state *, state,
ao2_find(states, ast_sorcery_object_get_id(obj), OBJ_SEARCH_KEY), ao2_cleanup);
RAII_VAR(struct sip_outbound_registration_state *, state, NULL, ao2_cleanup);
RAII_VAR(struct sip_outbound_registration_state *, new_state, NULL, ao2_cleanup);
struct sip_outbound_registration *applied = obj;
if (!states) {
/* Global container has gone. Likely shutting down. */
return -1;
}
state = ao2_find(states, ast_sorcery_object_get_id(applied), OBJ_SEARCH_KEY);
ast_debug(4, "Applying configuration to outbound registration '%s'\n", ast_sorcery_object_get_id(applied));
if (ast_strlen_zero(applied->server_uri)) {
@ -1089,7 +1069,15 @@ static int sip_outbound_registration_apply(const struct ast_sorcery *sorcery, vo
ast_debug(4,
"No change between old configuration and new configuration on outbound registration '%s'. Using previous state\n",
ast_sorcery_object_get_id(applied));
/*
* This is OK to replace without relinking the state in the
* current_states container since state->registration and
* applied have the same key.
*/
ao2_lock(states);
ao2_replace(state->registration, applied);
ao2_unlock(states);
return 0;
}
@ -1485,9 +1473,11 @@ static void *cli_retrieve_by_id(const char *id)
if (!obj) {
/* if the object no longer exists then remove its state */
ao2_find((states = ao2_global_obj_ref(current_states)),
id, OBJ_SEARCH_KEY | OBJ_UNLINK | OBJ_NODATA);
ao2_ref(states, -1);
states = ao2_global_obj_ref(current_states);
if (states) {
ao2_find(states, id, OBJ_SEARCH_KEY | OBJ_UNLINK | OBJ_NODATA);
ao2_ref(states, -1);
}
}
return obj;
@ -1604,14 +1594,66 @@ static void auth_observer(const char *type)
ao2_cleanup(regs);
}
const struct ast_sorcery_observer observer_callbacks = {
static const struct ast_sorcery_observer observer_callbacks_auth = {
.loaded = auth_observer,
};
static int check_state(void *obj, void *arg, int flags)
{
struct sip_outbound_registration_state *state = obj;
struct sip_outbound_registration *registration;
registration = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "registration",
ast_sorcery_object_get_id(state->registration));
if (!registration) {
/* This is a dead registration */
return CMP_MATCH;
}
ao2_ref(registration, -1);
return 0;
}
/*!
* \internal
* \brief Observer to purge dead registration states.
*
* \param name Module name owning the sorcery instance.
* \param sorcery Instance being observed.
* \param object_type Name of object being observed.
* \param reloaded Non-zero if the object is being reloaded.
*
* \return Nothing
*/
static void registration_loaded_observer(const char *name, const struct ast_sorcery *sorcery, const char *object_type, int reloaded)
{
struct ao2_container *states;
if (strcmp(object_type, "registration")) {
/* Not interested */
return;
}
states = ao2_global_obj_ref(current_states);
if (!states) {
/* Global container has gone. Likely shutting down. */
return;
}
/* Now to purge dead registrations. */
ao2_callback(states, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, check_state, NULL);
ao2_ref(states, -1);
}
static const struct ast_sorcery_instance_observer observer_callbacks_registrations = {
.object_type_loaded = registration_loaded_observer,
};
static int unload_module(void)
{
ast_sip_unregister_endpoint_identifier(&line_identifier);
ast_sorcery_observer_remove(ast_sip_get_sorcery(), "auth", &observer_callbacks);
ast_sorcery_observer_remove(ast_sip_get_sorcery(), "auth", &observer_callbacks_auth);
ast_sorcery_instance_observer_remove(ast_sip_get_sorcery(), &observer_callbacks_registrations);
ast_cli_unregister_multiple(cli_outbound_registration, ARRAY_LEN(cli_outbound_registration));
ast_sip_unregister_cli_formatter(cli_formatter);
ast_manager_unregister("PJSIPShowRegistrationsOutbound");
@ -1625,7 +1667,8 @@ static int unload_module(void)
static int load_module(void)
{
struct ao2_container *registrations, *new_states;
struct ao2_container *new_states;
CHECK_PJSIP_MODULE_LOADED();
ast_sorcery_apply_config(ast_sip_get_sorcery(), "res_pjsip_outbound_registration");
@ -1660,7 +1703,7 @@ static int load_module(void)
if (!cli_formatter) {
ast_log(LOG_ERROR, "Unable to allocate memory for cli formatter\n");
unload_module();
return -1;
return AST_MODULE_LOAD_FAILURE;
}
cli_formatter->name = "registration";
cli_formatter->print_header = cli_print_header;
@ -1682,14 +1725,15 @@ static int load_module(void)
ao2_global_obj_replace_unref(current_states, new_states);
ao2_ref(new_states, -1);
ast_sorcery_reload_object(ast_sip_get_sorcery(), "registration");
if (!(registrations = get_registrations())) {
if (ast_sorcery_instance_observer_add(ast_sip_get_sorcery(),
&observer_callbacks_registrations)) {
unload_module();
return AST_MODULE_LOAD_FAILURE;
}
ao2_ref(registrations, -1);
ast_sorcery_observer_add(ast_sip_get_sorcery(), "auth", &observer_callbacks);
ast_sorcery_load_object(ast_sip_get_sorcery(), "registration");
ast_sorcery_observer_add(ast_sip_get_sorcery(), "auth", &observer_callbacks_auth);
return AST_MODULE_LOAD_SUCCESS;
}
@ -1697,7 +1741,6 @@ static int load_module(void)
static int reload_module(void)
{
ast_sorcery_reload_object(ast_sip_get_sorcery(), "registration");
ao2_cleanup(get_registrations());
return 0;
}

Write Preview
Loading…
Cancel
Save