#include <babeltrace/plugin/plugin-internal.h>
#include <babeltrace/graph/component-class-internal.h>
#include <babeltrace/types.h>
+#include <babeltrace/list-internal.h>
#include <string.h>
#include <stdlib.h>
#include <glib.h>
#include <gmodule.h>
-#define NATIVE_PLUGIN_SUFFIX ".so"
+#define NATIVE_PLUGIN_SUFFIX "." G_MODULE_SUFFIX
#define NATIVE_PLUGIN_SUFFIX_LEN sizeof(NATIVE_PLUGIN_SUFFIX)
#define LIBTOOL_PLUGIN_SUFFIX ".la"
#define LIBTOOL_PLUGIN_SUFFIX_LEN sizeof(LIBTOOL_PLUGIN_SUFFIX)
DECLARE_SECTION(struct __bt_plugin_component_class_descriptor_attribute const *, __bt_plugin_component_class_descriptor_attributes);
/*
- * This hash table, global to the library, maps component class pointers
- * to shared library handles.
+ * This list, global to the library, keeps all component classes that
+ * have a reference to their shared library handles. It allows iteration
+ * on all component classes still present when the destructor executes
+ * to release the shared library handle references they might still have.
*
- * The keys (component classes) are NOT owned by this hash table, whereas
- * the values (shared library handles) are owned by this hash table.
- *
- * The keys are the component classes created with
+ * The list items are the component classes created with
* bt_plugin_add_component_class(). They keep the shared library handle
* object created by their plugin alive so that the plugin's code is
* not discarded when it could still be in use by living components
* created from those component classes:
*
- * [component] --ref-> [component class] --through this HT-> [shlib handle]
- *
- * This hash table exists for two reasons:
+ * [component] --ref-> [component class]-> [shlib handle]
*
- * 1. To allow this application:
+ * It allows this use-case:
*
* my_plugins = bt_plugin_create_all_from_file("/path/to/my-plugin.so");
* // instantiate components from a plugin's component classes
* // put plugins and free my_plugins here
* // user code of instantiated components still exists
*
- * 2. To decouple the plugin subsystem from the component subsystem:
- * while plugins objects need to know component class objects, the
- * opposite is not necessary, thus it makes no sense for a component
- * class to keep a reference to the plugin object from which it was
- * created.
- *
- * An entry is removed from this HT when a component class is destroyed
- * thanks to a custom destroy listener. When the entry is removed, the
- * GLib function calls the value destroy notifier of the HT, which is
- * bt_put(). This decreases the reference count of the mapped shared
- * library handle. Assuming the original plugin object which contained
- * some component classes is put first, when the last component class is
- * removed from this HT, the shared library handle object's reference
- * count falls to zero and the shared library is finally closed.
+ * An entry is removed from this list when a component class is
+ * destroyed thanks to a custom destroy listener. When the entry is
+ * removed, the entry is removed from the list, and we release the
+ * reference on the shlib handle. Assuming the original plugin object
+ * which contained some component classes is put first, when the last
+ * component class is removed from this list, the shared library handle
+ * object's reference count falls to zero and the shared library is
+ * finally closed.
*/
+
static
-GHashTable *comp_classes_to_shlib_handles;
-
-__attribute__((constructor)) static
-void init_comp_classes_to_shlib_handles(void) {
- comp_classes_to_shlib_handles = g_hash_table_new_full(g_direct_hash,
- g_direct_equal, NULL, bt_put);
- assert(comp_classes_to_shlib_handles);
- BT_LOGD_STR("Initialized component class to shared library handle hash table.");
-}
+BT_LIST_HEAD(component_class_list);
__attribute__((destructor)) static
-void fini_comp_classes_to_shlib_handles(void) {
- if (comp_classes_to_shlib_handles) {
- g_hash_table_destroy(comp_classes_to_shlib_handles);
- BT_LOGD_STR("Destroyed component class to shared library handle hash table.");
+void fini_comp_class_list(void)
+{
+ struct bt_component_class *comp_class, *tmp;
+
+ bt_list_for_each_entry_safe(comp_class, tmp, &component_class_list, node) {
+ bt_list_del(&comp_class->node);
+ BT_PUT(comp_class->so_handle);
}
+ BT_LOGD_STR("Released references from all component classes to shared library handles.");
}
static
shared_lib_handle->module = g_module_open(path, 0);
if (!shared_lib_handle->module) {
- BT_LOGW("Cannot open GModule: %s: path=\"%s\"",
+ /*
+ * DEBUG-level logging because we're only _trying_ to
+ * open this file as a Babeltrace plugin: if it's not,
+ * it's not an error. And because this can be tried
+ * during bt_plugin_create_all_from_dir(), it's not even
+ * a warning.
+ */
+ BT_LOGD("Cannot open GModule: %s: path=\"%s\"",
g_module_error(), path);
goto error;
}
cur_attr->value.version.extra);
break;
default:
+ /*
+ * WARN-level logging because this should not
+ * happen with the appropriate ABI version. If
+ * we're here, we know that for the reported
+ * version of the ABI, this attribute is
+ * unknown.
+ */
BT_LOGW("Ignoring unknown plugin descriptor attribute: "
"plugin-path=\"%s\", plugin-name=\"%s\", "
"attr-type-name=\"%s\", attr-type-id=%d",
cur_cc_descr_attr->value.notif_iter_seek_time_method;
break;
default:
+ /*
+ * WARN-level logging because
+ * this should not happen with
+ * the appropriate ABI version.
+ * If we're here, we know that
+ * for the reported version of
+ * the ABI, this attribute is
+ * unknown.
+ */
BT_LOGW("Ignoring unknown component class descriptor attribute: "
"plugin-path=\"%s\", "
"plugin-name=\"%s\", "
cc_full_descr->descriptor->methods.sink.consume);
break;
default:
+ /*
+ * WARN-level logging because this should not
+ * happen with the appropriate ABI version. If
+ * we're here, we know that for the reported
+ * version of the ABI, this component class type
+ * is unknown.
+ */
BT_LOGW("Ignoring unknown component class type: "
"plugin-path=\"%s\", plugin-name=\"%s\", "
"comp-class-name=\"%s\", comp-class-type=%d",
*
* This will call back
* bt_plugin_so_on_add_component_class() so that we can
- * add a mapping in comp_classes_to_shlib_handles when
+ * add a mapping in the component class list when
* we know the component class is successfully added.
*/
status = bt_plugin_add_component_class(plugin,
descriptor->name, descriptor->major, descriptor->minor);
if (descriptor->major > __BT_PLUGIN_VERSION_MAJOR) {
- BT_LOGW("Unknown ABI major version: abi-major=%d",
+ /*
+ * DEBUG-level logging because we're only
+ * _trying_ to open this file as a compatible
+ * Babeltrace plugin: if it's not, it's not an
+ * error. And because this can be tried during
+ * bt_plugin_create_all_from_dir(), it's not
+ * even a warning.
+ */
+ BT_LOGD("Unknown ABI major version: abi-major=%d",
descriptor->major);
goto error;
}
attrs_end, cc_descriptors_begin, cc_descriptors_end,
cc_descr_attrs_begin, cc_descr_attrs_end);
if (status < 0) {
- BT_LOGW_STR("Cannot initialize SO plugin object from sections.");
+ /*
+ * DEBUG-level logging because we're only
+ * _trying_ to open this file as a compatible
+ * Babeltrace plugin: if it's not, it's not an
+ * error. And because this can be tried during
+ * bt_plugin_create_all_from_dir(), it's not
+ * even a warning.
+ */
+ BT_LOGD_STR("Cannot initialize SO plugin object from sections.");
BT_PUT(plugin);
goto error;
}
shared_lib_handle = bt_plugin_so_shared_lib_handle_create(path);
if (!shared_lib_handle) {
- BT_LOGW_STR("Cannot create shared library handle.");
+ BT_LOGD_STR("Cannot create shared library handle.");
goto end;
}
void plugin_comp_class_destroy_listener(struct bt_component_class *comp_class,
void *data)
{
- gboolean exists = g_hash_table_remove(comp_classes_to_shlib_handles,
- comp_class);
- assert(exists);
- BT_LOGV("Component class destroyed: removed entry from hash table: "
+ bt_list_del(&comp_class->node);
+ BT_PUT(comp_class->so_handle);
+ BT_LOGV("Component class destroyed: removed entry from list: "
"comp-cls-addr=%p", comp_class);
}
assert(plugin->spec_data);
assert(plugin->type == BT_PLUGIN_TYPE_SO);
- /* Map component class pointer to shared lib handle in global HT */
- g_hash_table_insert(comp_classes_to_shlib_handles, comp_class,
- bt_get(spec->shared_lib_handle));
+ bt_list_add(&comp_class->node, &component_class_list);
+ comp_class->so_handle = bt_get(spec->shared_lib_handle);
/* Add our custom destroy listener */
bt_component_class_add_destroy_listener(comp_class,
projects / babeltrace.git / blobdiff