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loader: Create ast_module_running_ref. 

This function returns NULL if the module in question is not running.  I
did not change ast_module_ref as most callers do not check the result
and they always call ast_module_unref.

Make use of this function when running registered items from:
* app_stack API's
* bridge technologies
* CLI commands
* File formats
* Manager Actions
* RTP engines
* Sorcery Wizards
* Timing Interfaces
* Translators
* AGI Commands
* Fax Technologies

ASTERISK-20346 #close

Change-Id: Ia16fd28e188b2fc0b9d18b8a5d9cacc31df73fcc
This commit is contained in:
Corey Farrell 2017-12-29 19:24:02 -05:00
parent 7f4facc5e4
commit 55f1d69c43
13 changed files with 161 additions and 80 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/asterisk/module.h
View File

@ -357,6 +357,7 @@ void __ast_module_user_hangup_all(struct ast_module *);
#define ast_module_user_hangup_all() __ast_module_user_hangup_all(AST_MODULE_SELF)
struct ast_module *__ast_module_ref(struct ast_module *mod, const char *file, int line, const char *func);
struct ast_module *__ast_module_running_ref(struct ast_module *mod, const char *file, int line, const char *func);
void __ast_module_shutdown_ref(struct ast_module *mod, const char *file, int line, const char *func);
void __ast_module_unref(struct ast_module *mod, const char *file, int line, const char *func);
@ -369,6 +370,20 @@ void __ast_module_unref(struct ast_module *mod, const char *file, int line, cons
* from being unloaded.
*/
#define ast_module_ref(mod) __ast_module_ref(mod, __FILE__, __LINE__, __PRETTY_FUNCTION__)
/*!
* \brief Hold a reference to the module if it is running.
* \param mod Module to reference
* \retval mod if running
* \retval NULL if not running
*
* The returned pointer should be released with ast_module_unref.
*
* \note A module reference will prevent the module from being unloaded.
*/
#define ast_module_running_ref(mod) \
__ast_module_running_ref(mod, __FILE__, __LINE__, __PRETTY_FUNCTION__)
/*!
* \brief Prevent unload of the module before shutdown
* \param mod Module to hold

8
main/app.c
View File

@ -386,6 +386,7 @@ int ast_app_run_macro(struct ast_channel *autoservice_chan, struct ast_channel *
return res;
}
/* BUGBUG this is not thread safe. */
static const struct ast_app_stack_funcs *app_stack_callbacks;
void ast_install_stack_functions(const struct ast_app_stack_funcs *funcs)
@ -399,16 +400,16 @@ const char *ast_app_expand_sub_args(struct ast_channel *chan, const char *args)
const char *new_args;
funcs = app_stack_callbacks;
if (!funcs || !funcs->expand_sub_args) {
if (!funcs || !funcs->expand_sub_args || !ast_module_running_ref(funcs->module)) {
ast_log(LOG_WARNING,
"Cannot expand 'Gosub(%s)' arguments. The app_stack module is not available.\n",
args);
return NULL;
}
ast_module_ref(funcs->module);
new_args = funcs->expand_sub_args(chan, args);
ast_module_unref(funcs->module);
return new_args;
}
@ -418,13 +419,12 @@ int ast_app_exec_sub(struct ast_channel *autoservice_chan, struct ast_channel *s
int res;
funcs = app_stack_callbacks;
if (!funcs || !funcs->run_sub) {
if (!funcs || !funcs->run_sub || !ast_module_running_ref(funcs->module)) {
ast_log(LOG_WARNING,
"Cannot run 'Gosub(%s)'. The app_stack module is not available.\n",
sub_args);
return -1;
}
ast_module_ref(funcs->module);
if (autoservice_chan) {
ast_autoservice_start(autoservice_chan);

26
main/bridge.c
View File

@ -234,8 +234,21 @@ int __ast_bridge_technology_register(struct ast_bridge_technology *technology, s
/* Copy module pointer so reference counting can keep the module from unloading */
technology->mod = module;
/* Insert our new bridge technology into the list and print out a pretty message */
AST_RWLIST_INSERT_TAIL(&bridge_technologies, technology, entry);
/* Find the correct position to insert the technology. */
AST_RWLIST_TRAVERSE_SAFE_BEGIN(&bridge_technologies, current, entry) {
/* Put the highest preference tech's first in the list. */
if (technology->preference >= current->preference) {
AST_RWLIST_INSERT_BEFORE_CURRENT(technology, entry);
break;
}
}
AST_RWLIST_TRAVERSE_SAFE_END;
if (!current) {
/* Insert our new bridge technology to the end of the list. */
AST_RWLIST_INSERT_TAIL(&bridge_technologies, technology, entry);
}
AST_RWLIST_UNLOCK(&bridge_technologies);
@ -517,12 +530,17 @@ static struct ast_bridge_technology *find_best_technology(uint32_t capabilities,
current->name);
continue;
}
if (!ast_module_running_ref(current->mod)) {
ast_debug(1, "Bridge technology %s is not running, skipping.\n", current->name);
continue;
}
if (best) {
ast_module_unref(best->mod);
}
best = current;
}
if (best) {
/* Increment it's module reference count if present so it does not get unloaded while in use */
ast_module_ref(best->mod);
ast_debug(1, "Chose bridge technology %s\n", best->name);
}

17
main/cli.c
View File

@ -2679,9 +2679,12 @@ static char *__ast_cli_generator(const char *text, const char *word, int state,
.n = state - matchnum,
.argv = argv,
.argc = x};
ast_module_ref(e->module);
ret = e->handler(e, CLI_GENERATE, &a);
ast_module_unref(e->module);
/* If the command is in a module it must be running. */
if (!e->module || ast_module_running_ref(e->module)) {
ret = e->handler(e, CLI_GENERATE, &a);
ast_module_unref(e->module);
}
}
if (ret)
break;
@ -2760,9 +2763,11 @@ int ast_cli_command_full(int uid, int gid, int fd, const char *s)
*/
args[0] = (char *)e;
ast_module_ref(e->module);
retval = e->handler(e, CLI_HANDLER, &a);
ast_module_unref(e->module);
/* If the command is in a module it must be running. */
if (!e->module || ast_module_running_ref(e->module)) {
retval = e->handler(e, CLI_HANDLER, &a);
ast_module_unref(e->module);
}
if (retval == CLI_SHOWUSAGE) {
ast_cli(fd, "%s", S_OR(e->usage, "Invalid usage, but no usage information available.\n"));

12
main/file.c
View File

@ -425,11 +425,17 @@ static void filestream_destructor(void *arg)
static struct ast_filestream *get_filestream(struct ast_format_def *fmt, FILE *bfile)
{
struct ast_filestream *s;
int l = sizeof(*s) + fmt->buf_size + fmt->desc_size; /* total allocation size */
if ( (s = ao2_alloc(l, filestream_destructor)) == NULL)
if (!ast_module_running_ref(fmt->module)) {
return NULL;
ast_module_ref(fmt->module);
}
s = ao2_alloc(l, filestream_destructor);
if (!s) {
ast_module_unref(fmt->module);
return NULL;
}
s->fmt = fmt;
s->f = bfile;

10
main/loader.c
View File

@ -1702,6 +1702,16 @@ struct ast_module *__ast_module_ref(struct ast_module *mod, const char *file, in
return mod;
}
struct ast_module *__ast_module_running_ref(struct ast_module *mod,
const char *file, int line, const char *func)
{
if (!mod || !mod->flags.running) {
return NULL;
}
return __ast_module_ref(mod, file, line, func);
}
void __ast_module_shutdown_ref(struct ast_module *mod, const char *file, int line, const char *func)
{
if (!mod || mod->flags.keepuntilshutdown) {

79
main/manager.c
View File

@ -2923,34 +2923,41 @@ int ast_hook_send_action(struct manager_custom_hook *hook, const char *msg)
}
action = astman_get_header(&m, "Action");
if (strcasecmp(action, "login")) {
act_found = action_find(action);
if (act_found) {
/*
* we have to simulate a session for this action request
* to be able to pass it down for processing
* This is necessary to meet the previous design of manager.c
*/
s.hook = hook;
ao2_lock(act_found);
if (act_found->registered && act_found->func) {
if (act_found->module) {
ast_module_ref(act_found->module);
}
ao2_unlock(act_found);
ret = act_found->func(&s, &m);
ao2_lock(act_found);
if (act_found->module) {
ast_module_unref(act_found->module);
}
} else {
ret = -1;
}
ao2_unlock(act_found);
ao2_t_ref(act_found, -1, "done with found action object");
do {
if (!strcasecmp(action, "login")) {
break;
}
}
act_found = action_find(action);
if (!act_found) {
break;
}
/*
* we have to simulate a session for this action request
* to be able to pass it down for processing
* This is necessary to meet the previous design of manager.c
*/
s.hook = hook;
ret = -1;
ao2_lock(act_found);
if (act_found->registered && act_found->func) {
struct ast_module *mod_ref = ast_module_running_ref(act_found->module);
ao2_unlock(act_found);
/* If the action is in a module it must be running. */
if (!act_found->module || mod_ref) {
ret = act_found->func(&s, &m);
ast_module_unref(mod_ref);
}
} else {
ao2_unlock(act_found);
}
ao2_t_ref(act_found, -1, "done with found action object");
} while (0);
ast_free(dup_str);
return ret;
}
@ -6442,21 +6449,21 @@ static int process_message(struct mansession *s, const struct message *m)
if ((s->session->writeperm & act_found->authority)
|| act_found->authority == 0) {
/* We have the authority to execute the action. */
ret = -1;
ao2_lock(act_found);
if (act_found->registered && act_found->func) {
ast_debug(1, "Running action '%s'\n", act_found->action);
if (act_found->module) {
ast_module_ref(act_found->module);
}
struct ast_module *mod_ref = ast_module_running_ref(act_found->module);
ao2_unlock(act_found);
ret = act_found->func(s, m);
acted = 1;
ao2_lock(act_found);
if (act_found->module) {
ast_module_unref(act_found->module);
if (mod_ref || !act_found->module) {
ast_debug(1, "Running action '%s'\n", act_found->action);
ret = act_found->func(s, m);
acted = 1;
ast_module_unref(mod_ref);
}
} else {
ao2_unlock(act_found);
}
ao2_unlock(act_found);
}
if (!acted) {
/*

8
main/rtp_engine.c
View File

@ -428,6 +428,7 @@ struct ast_rtp_instance *ast_rtp_instance_new(const char *engine_name,
struct ast_sockaddr address = {{0,}};
struct ast_rtp_instance *instance = NULL;
struct ast_rtp_engine *engine = NULL;
struct ast_module *mod_ref;
AST_RWLIST_RDLOCK(&engines);
@ -450,10 +451,15 @@ struct ast_rtp_instance *ast_rtp_instance_new(const char *engine_name,
}
/* Bump up the reference count before we return so the module can not be unloaded */
ast_module_ref(engine->mod);
mod_ref = ast_module_running_ref(engine->mod);
AST_RWLIST_UNLOCK(&engines);
if (!mod_ref) {
/* BUGBUG: improve handling of this situation. */
return NULL;
}
/* Allocate a new RTP instance */
if (!(instance = ao2_alloc(sizeof(*instance), instance_destructor))) {
ast_module_unref(engine->mod);

13
main/sorcery.c
View File

@ -835,16 +835,19 @@ enum ast_sorcery_apply_result __ast_sorcery_insert_wizard_mapping(struct ast_sor
RAII_VAR(struct ast_sorcery_object_wizard *, object_wizard, ao2_alloc(sizeof(*object_wizard), sorcery_object_wizard_destructor), ao2_cleanup);
int created = 0;
if (!wizard) {
if (!object_wizard) {
return AST_SORCERY_APPLY_FAIL;
}
if (!wizard || wizard->callbacks.module != ast_module_running_ref(wizard->callbacks.module)) {
ast_log(LOG_ERROR, "Wizard '%s' could not be applied to object type '%s' as it was not found\n",
name, type);
return AST_SORCERY_APPLY_FAIL;
} else if (!object_wizard) {
return AST_SORCERY_APPLY_FAIL;
}
if (!object_type) {
if (!(object_type = sorcery_object_type_alloc(type, module))) {
ast_module_unref(wizard->callbacks.module);
return AST_SORCERY_APPLY_FAIL;
}
created = 1;
@ -861,6 +864,7 @@ enum ast_sorcery_apply_result __ast_sorcery_insert_wizard_mapping(struct ast_sor
ast_debug(1, "Wizard %s already applied to object type %s\n",
wizard->callbacks.name, object_type->name);
AST_VECTOR_RW_UNLOCK(&object_type->wizards);
ast_module_unref(wizard->callbacks.module);
return AST_SORCERY_APPLY_DUPLICATE;
}
}
@ -871,11 +875,10 @@ enum ast_sorcery_apply_result __ast_sorcery_insert_wizard_mapping(struct ast_sor
ast_log(LOG_WARNING, "Wizard '%s' failed to open mapping for object type '%s' with data: %s\n",
name, object_type->name, S_OR(data, ""));
AST_VECTOR_RW_UNLOCK(&object_type->wizards);
ast_module_unref(wizard->callbacks.module);
return AST_SORCERY_APPLY_FAIL;
}
ast_module_ref(wizard->callbacks.module);
object_wizard->wizard = ao2_bump(wizard);
object_wizard->caching = caching;

11
main/timing.c
View File

@ -124,17 +124,22 @@ struct ast_timer *ast_timer_open(void)
void *data = NULL;
struct timing_holder *h;
struct ast_timer *t = NULL;
int idx = 1;
ast_heap_rdlock(timing_interfaces);
if ((h = ast_heap_peek(timing_interfaces, 1))) {
data = h->iface->timer_open();
ast_module_ref(h->mod);
while ((h = ast_heap_peek(timing_interfaces, idx))) {
if (ast_module_running_ref(h->mod)) {
data = h->iface->timer_open();
break;
}
idx++;
}
if (data) {
if (!(t = ast_calloc(1, sizeof(*t)))) {
h->iface->timer_close(data);
ast_module_unref(h->mod);
} else {
t->data = data;
t->holder = h;

5
main/translate.c
View File

@ -342,7 +342,10 @@ static struct ast_trans_pvt *newpvt(struct ast_translator *t, struct ast_format
*/
pvt->explicit_dst = ao2_bump(explicit_dst);
ast_module_ref(t->module);
if (!ast_module_running_ref(t->module)) {
ast_free(pvt);
return NULL;
}
/* call local init routine, if present */
if (t->newpvt && t->newpvt(pvt)) {

29
res/res_agi.c
View File

@ -4040,14 +4040,19 @@ static enum agi_result agi_handle_command(struct ast_channel *chan, AGI *agi, ch
parse_args(buf, &argc, argv);
c = find_command(argv, 0);
if (c && (!dead || (dead && c->dead))) {
/* if this command wasn't registered by res_agi, be sure to usecount
the module we are using */
if (c->mod != ast_module_info->self)
ast_module_ref(c->mod);
if (!c || !ast_module_running_ref(c->mod)) {
ami_res = "Invalid or unknown command";
resultcode = 510;
ast_agi_send(agi->fd, chan, "%d %s\n", resultcode, ami_res);
publish_async_exec_end(chan, command_id, ami_cmd, resultcode, ami_res);
return AGI_RESULT_SUCCESS;
}
if (!dead || (dead && c->dead)) {
res = c->handler(chan, agi, argc, argv);
if (c->mod != ast_module_info->self)
ast_module_unref(c->mod);
switch (res) {
case RESULT_SHOWUSAGE:
ami_res = "Usage";
@ -4094,21 +4099,15 @@ static enum agi_result agi_handle_command(struct ast_channel *chan, AGI *agi, ch
break;
}
} else if (c) {
} else {
ami_res = "Command Not Permitted on a dead channel or intercept routine";
resultcode = 511;
ast_agi_send(agi->fd, chan, "%d %s\n", resultcode, ami_res);
publish_async_exec_end(chan, command_id, ami_cmd, resultcode, ami_res);
} else {
ami_res = "Invalid or unknown command";
resultcode = 510;
ast_agi_send(agi->fd, chan, "%d %s\n", resultcode, ami_res);
publish_async_exec_end(chan, command_id, ami_cmd, resultcode, ami_res);
}
ast_module_unref(c->mod);
return AGI_RESULT_SUCCESS;
}

8
res/res_fax.c
View File

@ -1161,8 +1161,10 @@ static struct ast_fax_session *fax_session_reserve(struct ast_fax_session_detail
if ((faxmod->tech->caps & details->caps) != details->caps) {
continue;
}
if (!ast_module_running_ref(faxmod->tech->module)) {
continue;
}
ast_debug(4, "Reserving a FAX session from '%s'.\n", faxmod->tech->description);
ast_module_ref(faxmod->tech->module);
s->tech = faxmod->tech;
break;
}
@ -1279,8 +1281,10 @@ static struct ast_fax_session *fax_session_new(struct ast_fax_session_details *d
if ((faxmod->tech->caps & details->caps) != details->caps) {
continue;
}
if (!ast_module_running_ref(faxmod->tech->module)) {
continue;
}
ast_debug(4, "Requesting a new FAX session from '%s'.\n", faxmod->tech->description);
ast_module_ref(faxmod->tech->module);
if (reserved) {
/* Balance module ref from reserved session */
ast_module_unref(reserved->tech->module);