cli: fix bt_plugin leak when using `-i ctf`

When running:

    libtool --mode=execute valgrind --leak-check=full  ./src/cli/babeltrace2 /home/smarchi/src/babeltrace/tests/data/ctf-traces/succeed/succeed1 -i ctf

I get:

    2,680 (168 direct, 2,512 indirect) bytes in 1 blocks are definitely lost in loss record 56 of 58
       at 0x4C31B25: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
       by 0x5360B10: g_malloc0 (gmem.c:129)
       by 0x4E97502: bt_plugin_create_empty (plugin.h:178)
       by 0x4E9AD72: bt_plugin_so_create_empty (plugin-so.c:1239)
       by 0x4E9B0D1: bt_plugin_so_create_all_from_sections (plugin-so.c:1342)
       by 0x4E9BFBF: bt_plugin_so_create_all_from_file (plugin-so.c:1678)
       by 0x4E93FB4: bt_plugin_find_all_from_file (plugin.c:210)
       by 0x4E95300: nftw_append_all_from_dir (plugin.c:551)
       by 0x5956F13: process_entry (ftw.c:464)
       by 0x59573BA: ftw_dir (ftw.c:543)
       by 0x5957BEB: ftw_startup (ftw.c:768)
       by 0x4E95748: bt_plugin_create_append_all_from_dir (plugin.c:641)

The call to find_loaded_plugin at babeltrace2-cfg-cli-args.c:4013
returns a new reference to the plugin, for which we don't have a
corresponding put_ref.

Looking at all the users of find_loaded_plugin, they only really need to
borrow the plugin, so rather than add a put_ref, I've made it so
find_loaded_plugin returns a borrowed reference instead of a new
reference.  For clarity, I've renamed that function to
borrow_loaded_plugin_by_name.  And for consistency, I've renamed
borrow_loaded_plugin to borrow_loaded_plugin_by_index.

Change-Id: I19234bda6e219efa3e55da760846d138c381fac4
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reported-by: Valgrind Memcheck
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2731
Tested-by: jenkins <jenkins@lttng.org>

diff --git a/src/cli/babeltrace2-cfg-cli-args.c b/src/cli/babeltrace2-cfg-cli-args.c
index 381fc484e48c1696b5e613778c317ed0920acc52..e6fce2f7a2f92901632d5586db1839804a4b4f31 100644 (file)
--- a/src/cli/babeltrace2-cfg-cli-args.c
+++ b/src/cli/babeltrace2-cfg-cli-args.c
@@ -4010,7 +4010,7 @@ struct bt_config *bt_config_convert_from_args(int argc, const char *argv[],
 
                        if (auto_source_discovery_restrict_plugin_name) {
                                plugin_count = 1;
-                               plugin = find_loaded_plugin(auto_source_discovery_restrict_plugin_name);
+                               plugin = borrow_loaded_plugin_by_name(auto_source_discovery_restrict_plugin_name);
                                plugins = &plugin;
                        } else {
                                plugin_count = get_loaded_plugins_count();

diff --git a/src/cli/babeltrace2-plugins.c b/src/cli/babeltrace2-plugins.c
index 8fdfe3e726008671bea3a81f37661750b1194699..223f09ad39b06ed5be9defc04ea4236a2bd520b6 100644 (file)
--- a/src/cli/babeltrace2-plugins.c
+++ b/src/cli/babeltrace2-plugins.c
@@ -44,7 +44,7 @@ void fini_loaded_plugins(void)
        g_ptr_array_free(loaded_plugins, TRUE);
 }
 
-const bt_plugin *find_loaded_plugin(const char *name)
+const bt_plugin *borrow_loaded_plugin_by_name(const char *name)
 {
        int i;
        const bt_plugin *plugin = NULL;
@@ -69,7 +69,6 @@ const bt_plugin *find_loaded_plugin(const char *name)
                BT_LOGI("Cannot find plugin: name=\"%s\"", name);
        }
 
-       bt_plugin_get_ref(plugin);
        return plugin;
 }
 
@@ -83,7 +82,7 @@ const bt_plugin **borrow_loaded_plugins(void)
        return (const bt_plugin **) loaded_plugins->pdata;
 }
 
-const bt_plugin *borrow_loaded_plugin(size_t index)
+const bt_plugin *borrow_loaded_plugin_by_index(size_t index)
 {
        BT_ASSERT(index < loaded_plugins->len);
        return g_ptr_array_index(loaded_plugins, index);
@@ -102,7 +101,7 @@ void add_to_loaded_plugins(const bt_plugin_set *plugin_set)
                const bt_plugin *plugin =
                        bt_plugin_set_borrow_plugin_by_index_const(plugin_set, i);
                const bt_plugin *loaded_plugin =
-                       find_loaded_plugin(bt_plugin_get_name(plugin));
+                       borrow_loaded_plugin_by_name(bt_plugin_get_name(plugin));
 
                BT_ASSERT(plugin);
 
@@ -113,7 +112,6 @@ void add_to_loaded_plugins(const bt_plugin_set *plugin_set)
                                bt_plugin_get_name(plugin),
                                bt_plugin_get_path(plugin),
                                bt_plugin_get_path(loaded_plugin));
-                       bt_plugin_put_ref(loaded_plugin);
                } else {
                        /* Add to global array. */
                        BT_LOGD("Adding plugin to loaded plugins: plugin-path=\"%s\"",

diff --git a/src/cli/babeltrace2-plugins.h b/src/cli/babeltrace2-plugins.h
index 60354d370b1117db19a841d28ef97b509810729d..2dd55d85bcd0133fb844ee183e6f4d5b1d3886a2 100644 (file)
--- a/src/cli/babeltrace2-plugins.h
+++ b/src/cli/babeltrace2-plugins.h
@@ -33,9 +33,10 @@ BT_HIDDEN void fini_loaded_plugins(void);
 
 BT_HIDDEN int require_loaded_plugins(const bt_value *plugin_paths);
 
-BT_HIDDEN const bt_plugin *find_loaded_plugin(const char *name);
 BT_HIDDEN size_t get_loaded_plugins_count(void);
 BT_HIDDEN const bt_plugin **borrow_loaded_plugins(void);
-BT_HIDDEN const bt_plugin *borrow_loaded_plugin(size_t index);
+BT_HIDDEN const bt_plugin *borrow_loaded_plugin_by_index(size_t index);
+BT_HIDDEN const bt_plugin *borrow_loaded_plugin_by_name(const char *name);
+
 
 #endif /* CLI_BABELTRACE_PLUGINS_H */

diff --git a/src/cli/babeltrace2.c b/src/cli/babeltrace2.c
index ad8ec4b711d3593dbd2ae36252d910795ca8a73d..0dfac7a8ec077d8ca42c6da1a45f1a20c1fd0275 100644 (file)
--- a/src/cli/babeltrace2.c
+++ b/src/cli/babeltrace2.c
@@ -146,14 +146,13 @@ const void *find_component_class_from_plugin(const char *plugin_name,
        BT_LOGI("Finding component class: plugin-name=\"%s\", "
                "comp-cls-name=\"%s\"", plugin_name, comp_class_name);
 
-       plugin = find_loaded_plugin(plugin_name);
+       plugin = borrow_loaded_plugin_by_name(plugin_name);
        if (!plugin) {
                goto end;
        }
 
        comp_class = plugin_borrow_comp_cls_func(plugin, comp_class_name);
        bt_object_get_ref(comp_class);
-       BT_PLUGIN_PUT_REF_AND_RESET(plugin);
 
 end:
        if (comp_class) {
@@ -726,7 +725,7 @@ enum bt_cmd_status cmd_help(struct bt_config *cfg)
        const bt_plugin *plugin = NULL;
        const bt_component_class *needed_comp_cls = NULL;
 
-       plugin = find_loaded_plugin(cfg->cmd_data.help.cfg_component->plugin_name->str);
+       plugin = borrow_loaded_plugin_by_name(cfg->cmd_data.help.cfg_component->plugin_name->str);
        if (!plugin) {
                BT_CLI_LOGE_APPEND_CAUSE(
                        "Cannot find plugin: plugin-name=\"%s\"",
@@ -780,7 +779,6 @@ error:
 
 end:
        bt_component_class_put_ref(needed_comp_cls);
-       bt_plugin_put_ref(plugin);
        return cmd_status;
 }
 
@@ -854,7 +852,7 @@ enum bt_cmd_status cmd_list_plugins(struct bt_config *cfg)
        }
 
        for (i = 0; i < plugins_count; i++) {
-               const bt_plugin *plugin = borrow_loaded_plugin(i);
+               const bt_plugin *plugin = borrow_loaded_plugin_by_index(i);
 
                component_classes_count +=
                        bt_plugin_get_source_component_class_count(plugin) +
@@ -871,7 +869,7 @@ enum bt_cmd_status cmd_list_plugins(struct bt_config *cfg)
                bt_common_color_reset());
 
        for (i = 0; i < plugins_count; i++) {
-               const bt_plugin *plugin = borrow_loaded_plugin(i);
+               const bt_plugin *plugin = borrow_loaded_plugin_by_index(i);
 
                printf("\n");
                print_plugin_info(plugin);