* the validator's function pointer.
*
* The reason for this seamingly useless indirection is the way function
- * pointers interfere with module loading. Asterisk attempts to dlopen() each
- * module using \c RTLD_LAZY in order to read some metadata from the module.
- * Unfortunately, if you take the address of a function, the function has to be
- * resolvable at load time, even if \c RTLD_LAZY is specified. By moving the
- * function-address-taking into this module, we can once again be lazy.
+ * pointers used to interfere with module loading. Previously, Asterisk
+ * attempted to dlopen() each module using \c RTLD_LAZY in order to read some
+ * metadata from the module. Using functions to get the function pointer
+ * allowed us to be lazy.
*/
/*
* \brief Implementation of the stasis_message_sink_cb() callback.
*
* Why the roundabout way of exposing this via stasis_message_sink_cb()? Well,
- * it has to do with how we load modules.
+ * it has to do with how we previously loaded modules, using \c RTLD_LAZY.
*
- * Modules have their own metadata compiled into them in the module info block
- * at the end of the file. This includes dependency information in the
- * \c nonoptreq field.
- *
- * Asterisk loads the module, inspects the field, then loads any needed
- * dependencies. This works because Asterisk passes \c RTLD_LAZY to the initial
- * dlopen(), which defers binding function references until they are called.
- *
- * But when you take the address of a function, that function needs to be
- * available at load time. So if some module used the address of
- * message_sink_cb() directly, and \c res_stasis_test.so wasn't loaded yet, then
- * that module would fail to load.
- *
- * The stasis_message_sink_cb() function gives us a layer of indirection so that
- * the initial lazy binding will still work as expected.
+ * The stasis_message_sink_cb() function gave us a layer of indirection so that
+ * the initial lazy binding would still work as expected.
*/
static void message_sink_cb(void *data, struct stasis_subscription *sub,
struct stasis_message *message)
* the validator's function pointer.
*
* The reason for this seamingly useless indirection is the way function
- * pointers interfere with module loading. Asterisk attempts to dlopen() each
- * module using \c RTLD_LAZY in order to read some metadata from the module.
- * Unfortunately, if you take the address of a function, the function has to be
- * resolvable at load time, even if \c RTLD_LAZY is specified. By moving the
- * function-address-taking into this module, we can once again be lazy.
+ * pointers used to interfere with module loading. Previously, Asterisk
+ * attempted to dlopen() each module using \c RTLD_LAZY in order to read some
+ * metadata from the module. Using functions to get the function pointer
+ * allowed us to be lazy.
*/
/*
/*!
* Wrapper of ast_test_validate_int() so an external function pointer is not used.
*
- * \note Must do this because using an external function pointer
- * does not play nicely when loading with RTLD_LAZY.
+ * \note We do this because using an external function pointer
+ * did not play nicely when we loaded with RTLD_LAZY.
*/
static int wrap_ast_ari_validate_int(struct ast_json *json)
{
/*!
* Wrapper of ast_ari_validate_string() so an external function pointer is not used.
*
- * \note Must do this because using an external function pointer
- * does not play nicely when loading with RTLD_LAZY.
+ * \note We do this because using an external function pointer
+ * did not play nicely when we loaded with RTLD_LAZY.
*/
static int wrap_ast_ari_validate_string(struct ast_json *json)
{