datastore: Add automatic module references.

Add a reference to the calling module when it is active to protect
access to datastore->info.  Remove module references done by
func_periodic_hook as the datastore now handles it.

ASTERISK-25128 #close

Change-Id: I8357a3711e77591d0d1dd8ab4211a7eedd782c89

funcs/func_periodic_hook.c

@@ -137,8 +137,6 @@ static void hook_datastore_destroy_callback(void *data)
 	ast_free(state->context);
 	ast_free(state->exten);
 	ast_free(state);
-
-	ast_module_unref(ast_module_info->self);
 }
 
 static const struct ast_datastore_info hook_datastore = {
@@ -305,7 +303,7 @@ static int init_hook(struct ast_channel *chan, const char *context, const char *
 	if (!(datastore = ast_datastore_alloc(&hook_datastore, uid))) {
 		return -1;
 	}
-	ast_module_ref(ast_module_info->self);
+
 	if (!(state = hook_state_alloc(context, exten, interval, hook_id))) {
 		ast_datastore_free(datastore);
 		return -1;

include/asterisk/datastore.h

@@ -69,6 +69,7 @@ struct ast_datastore {
 	const char *uid;			/*!< Unique data store identifier */
 	void *data;				/*!< Contained data */
 	const struct ast_datastore_info *info;	/*!< Data store type information */
+	struct ast_module *mod;			/*!< Module referenced by this datastore */
 	unsigned int inheritance;		/*!< Number of levels this item will continue to be inherited */
 	AST_LIST_ENTRY(ast_datastore) entry; 	/*!< Used for easy linking */
 };
@@ -77,13 +78,16 @@ struct ast_datastore {
  * \brief Create a data store object
  * \param[in] info information describing the data store object
  * \param[in] uid unique identifer
+ * \param[in] mod The module to hold until this datastore is freed.
  * \param file, line, function
  * \version 1.6.1 moved here and renamed from ast_channel_datastore_alloc
  */
-struct ast_datastore * attribute_malloc __ast_datastore_alloc(const struct ast_datastore_info *info, const char *uid,
+struct ast_datastore * attribute_malloc __ast_datastore_alloc(
+	const struct ast_datastore_info *info, const char *uid, struct ast_module *mod,
 	const char *file, int line, const char *function);
 
-#define ast_datastore_alloc(info, uid) __ast_datastore_alloc(info, uid, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+#define ast_datastore_alloc(info, uid) \
+	__ast_datastore_alloc(info, uid, AST_MODULE_SELF, __FILE__, __LINE__, __PRETTY_FUNCTION__)
 
 /*!
  * \brief Free a data store object

main/datastore.c

@@ -31,11 +31,13 @@
 #include "asterisk/utils.h"
 #include "asterisk/astobj2.h"
 #include "asterisk/uuid.h"
+#include "asterisk/module.h"
 
 /*! \brief Number of buckets for datastore container */
 #define DATASTORE_BUCKETS 53
 
-struct ast_datastore *__ast_datastore_alloc(const struct ast_datastore_info *info, const char *uid,
+struct ast_datastore *__ast_datastore_alloc(
+	const struct ast_datastore_info *info, const char *uid, struct ast_module *mod,
 	const char *file, int line, const char *function)
 {
 	struct ast_datastore *datastore = NULL;
@@ -50,12 +52,15 @@ struct ast_datastore *__ast_datastore_alloc(const struct ast_datastore_info *inf
 	}
 
 	datastore->info = info;
+	datastore->mod = mod;
 
 	if (!ast_strlen_zero(uid) && !(datastore->uid = ast_strdup(uid))) {
 		ast_free(datastore);
 		datastore = NULL;
 	}
 
+	ast_module_ref(mod);
+
 	return datastore;
 }
 
@@ -75,6 +80,8 @@ int ast_datastore_free(struct ast_datastore *datastore)
 		datastore->uid = NULL;
 	}
 
+	ast_module_unref(datastore->mod);
+
 	/* Finally free memory used by ourselves */
 	ast_free(datastore);