wmem: allow wmem_destroy_list to ignore a NULL list.
[metze/wireshark/wip.git] / extcap.c
index 466f83c958cca454c05b6ef9a9899828476f38c2..cdd8e0f70e02cb6792f90e8baa5f2d6077fe504f 100644 (file)
--- a/extcap.c
+++ b/extcap.c
@@ -90,13 +90,67 @@ typedef struct _extcap_callback_info_t
 /* Callback definition for extcap_foreach */
 typedef gboolean(*extcap_cb_t)(extcap_callback_info_t info_structure);
 
-typedef struct extcap_output_info {
-    char *extcap_path;
-    char *output;
-} extcap_output_info_t;
+/** GThreadPool does not support pushing new work from a thread while waiting
+ * for the thread pool to finish. This data structure tracks ongoing work.
+ * See https://gitlab.gnome.org/GNOME/glib/issues/1598 */
+typedef struct thread_pool {
+    GThreadPool    *pool;
+    gint            count;  /**< Number of tasks that have not finished. */
+    GCond           cond;
+    GMutex          data_mutex;
+} thread_pool_t;
+
+/**
+ * Callback definition for extcap_run_all, invoked with a thread pool (to
+ * schedule new tasks), an opaque data parameter, and the output from last task
+ * (or NULL if it failed). The output must be freed by the callback function.
+ * The implementation MUST be thread-safe.
+ */
+typedef void (*extcap_run_cb_t)(thread_pool_t *pool, void *data, char *output);
+
+typedef struct extcap_run_task {
+    const char     *extcap_path;
+    char          **argv;       /**< NULL-terminated arguments list, freed when the task is completed. */
+    extcap_run_cb_t output_cb;
+    void           *data;       /** Parameter to be passed to output_cb. */
+} extcap_run_task_t;
+
+typedef struct extcap_iface_info {
+    char *ifname;                       /**< Interface name. */
+    char *output;                       /**< Output of --extcap-config. */
+} extcap_iface_info_t;
+
+typedef struct extcap_run_extcaps_info {
+    char    *extcap_path;               /**< Extcap program path, MUST be the first member.  */
+    char    *output;                    /**< Output of --extcap-interfaces. */
+    guint   num_interfaces;             /**< Number of discovered interfaces. */
+    extcap_iface_info_t *iface_infos;   /**< Per-interface information. */
+} extcap_run_extcaps_info_t;
+
 
 static void extcap_load_interface_list(void);
 
+static gboolean
+thread_pool_push(thread_pool_t *pool, gpointer data, GError **error)
+{
+    g_mutex_lock(&pool->data_mutex);
+    ++pool->count;
+    g_mutex_unlock(&pool->data_mutex);
+    return g_thread_pool_push(pool->pool, data, error);
+}
+
+static void
+thread_pool_wait(thread_pool_t *pool)
+{
+    g_mutex_lock(&pool->data_mutex);
+    while (pool->count != 0) {
+        g_cond_wait(&pool->cond, &pool->data_mutex);
+    }
+    g_cond_clear(&pool->cond);
+    g_mutex_unlock(&pool->data_mutex);
+    g_mutex_clear(&pool->data_mutex);
+}
+
 GHashTable *
 extcap_loaded_interfaces(void)
 {
@@ -290,11 +344,17 @@ static void extcap_free_array(gchar ** args, int argc)
 }
 
 static void
-extcap_free_output_info_array(extcap_output_info_t *infos, guint count)
+extcap_free_extcaps_info_array(extcap_run_extcaps_info_t *infos, guint count)
 {
     for (guint i = 0; i < count; i++) {
         g_free(infos[i].extcap_path);
         g_free(infos[i].output);
+        for (guint j = 0; j < infos[i].num_interfaces; j++) {
+            extcap_iface_info_t *iface_info = &infos[i].iface_infos[j];
+            g_free(iface_info->ifname);
+            g_free(iface_info->output);
+        }
+        g_free(infos[i].iface_infos);
     }
     g_free(infos);
 }
@@ -320,36 +380,48 @@ extcap_run_one(const extcap_interface *interface, GList *arguments, extcap_cb_t
     extcap_free_array(args, cnt);
 }
 
-/** Thread callback to run an extcap program and save its output. */
+/** Thread callback to run an extcap program and pass its output. */
 static void
 extcap_thread_callback(gpointer data, gpointer user_data)
 {
-    extcap_output_info_t *info = (extcap_output_info_t *)data;
-    GList **arguments_lists = (GList **)user_data;
+    extcap_run_task_t *task = (extcap_run_task_t *)data;
+    thread_pool_t *pool = (thread_pool_t *)user_data;
     const char *dirname = get_extcap_dir();
 
-    // Try normal and fallback arguments.
-    for (int i = 0; i < 2; i++) {
-        GList *arguments = arguments_lists[i];
-        gchar **args = extcap_convert_arguments_to_array(arguments);
-        char *command_output;
-        if (ws_pipe_spawn_sync(dirname, info->extcap_path, g_list_length(arguments), args, &command_output)) {
-            info->output = command_output;
-            extcap_free_array(args, g_list_length(arguments));
-            break;
-        }
-        extcap_free_array(args, g_list_length(arguments));
+    char *command_output;
+    if (ws_pipe_spawn_sync(dirname, task->extcap_path, g_strv_length(task->argv), task->argv, &command_output)) {
+        task->output_cb(pool, task->data, command_output);
+    } else {
+        task->output_cb(pool, task->data, NULL);
+    }
+    g_strfreev(task->argv);
+    g_free(task);
+
+    // Notify when all tasks are completed and no new subtasks were created.
+    g_mutex_lock(&pool->data_mutex);
+    if (--pool->count == 0) {
+        g_cond_signal(&pool->cond);
     }
+    g_mutex_unlock(&pool->data_mutex);
 }
 
 /*
- * Run all extcap programs with the given arguments. Returns an array of outputs
- * for each tool (or NULL if no tools are found) with its size in 'count'.
- * Destroy the returneed value with extcap_free_output_info_array.
+ * Run all extcap programs with the given arguments list, invoke the callback to
+ * do some processing and return the results.
+ *
+ * @param [IN] argv NULL-terminated arguments list.
+ * @param [IN] output_cb Thread callback function that receives the output.
+ * @param [IN] data_size Size of the per-program information that will be returned.
+ * @param [OUT] count Size of the returned array.
+ * @return Array of information or NULL if there are none. The first member of
+ * each element (char *extcap_path) must be freed.
  */
-static extcap_output_info_t *
-extcap_run_all(GList *arguments, GList *fallback_arguments, guint *count)
+static gpointer
+extcap_run_all(const char *argv[], extcap_run_cb_t output_cb, gsize data_size, guint *count)
 {
+    /* Need enough space for at least 'extcap_path'. */
+    g_assert(data_size >= sizeof(char *));
+
     GSList *paths = extcap_get_extcap_paths();
     int i = 0;
 #if GLIB_CHECK_VERSION(2,36,0)
@@ -366,17 +438,32 @@ extcap_run_all(GList *arguments, GList *fallback_arguments, guint *count)
     }
 
     guint64 start_time = g_get_monotonic_time();
-    GList *both_args[] = { arguments, fallback_arguments };
     guint paths_count = g_slist_length(paths);
-    extcap_output_info_t *infos = g_new0(extcap_output_info_t, paths_count);
+    /* GSList is not thread-safe, so pre-allocate an array instead. */
+    gpointer infos = g_malloc0_n(paths_count, data_size);
+
+    thread_pool_t pool;
+    pool.pool = g_thread_pool_new(extcap_thread_callback, &pool, max_threads, FALSE, NULL);
+    pool.count = 0;
+    g_cond_init(&pool.cond);
+    g_mutex_init(&pool.data_mutex);
 
-    GThreadPool *pool = g_thread_pool_new(extcap_thread_callback, both_args, max_threads, FALSE, NULL);
     for (GSList *path = paths; path; path = g_slist_next(path), i++) {
-        infos[i].extcap_path = (char *)path->data;
-        g_thread_pool_push(pool, &infos[i], NULL);
+        extcap_run_task_t *task = g_new0(extcap_run_task_t, 1);
+
+        task->extcap_path = (char *)path->data;
+        task->argv = g_strdupv((char **)argv);
+        task->output_cb = output_cb;
+        task->data = ((char *)infos) + (i * data_size);
+        *((char **)task->data) = (char *)path->data;
+
+        thread_pool_push(&pool, task, NULL);
     }
-    g_thread_pool_free(pool, FALSE, TRUE);  /* Waits for tasks completion. */
-    g_slist_free(paths);
+    g_slist_free(paths);    /* Note: the contents are transferred to 'infos'. */
+
+    /* Wait for all (sub)tasks to complete. */
+    thread_pool_wait(&pool);
+    g_thread_pool_free(pool.pool, FALSE, TRUE);
 
     g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "extcap: completed discovery of %d tools in %.3fms",
             paths_count, (g_get_monotonic_time() - start_time) / 1000.0);
@@ -594,17 +681,6 @@ append_extcap_interface_list(GList *list, char **err_str _U_)
     return list;
 }
 
-static void
-extcap_register_preferences_callback(gpointer key, gpointer value _U_, gpointer user_data _U_)
-{
-    GList *arguments;
-
-    arguments = extcap_get_if_configuration((gchar *)key);
-    /* Memory for prefs are external to an interface, they are part of
-     * extcap core, so the parsed arguments can be freed. */
-    extcap_free_if_configuration(arguments, TRUE);
-}
-
 void extcap_register_preferences(void)
 {
     if (prefs.capture_no_extcap)
@@ -617,11 +693,8 @@ void extcap_register_preferences(void)
         return;
     }
 
-    if ( !_loaded_interfaces || g_hash_table_size(_loaded_interfaces) == 0 )
-        extcap_load_interface_list();
-
-
-    g_hash_table_foreach(_tool_for_ifname, extcap_register_preferences_callback, NULL);
+    // Will load information about extcaps and their supported config.
+    extcap_load_interface_list();
 }
 
 /**
@@ -840,7 +913,7 @@ static gboolean cb_reload_preference(extcap_callback_info_t cb_info)
 
     arguments = extcap_parse_values(cb_info.output);
 
-    walker = g_list_first((GList *)(arguments));
+    walker = g_list_first(arguments);
     while (walker != NULL)
     {
         extcap_value * val = (extcap_value *)walker->data;
@@ -906,7 +979,7 @@ extcap_has_configuration(const char *ifname, gboolean is_required)
 
     gboolean found = FALSE;
 
-    arguments = extcap_get_if_configuration((const char *)(ifname));
+    arguments = extcap_get_if_configuration(ifname);
     walker = g_list_first(arguments);
 
     while (walker != NULL && !found)
@@ -1718,7 +1791,7 @@ process_new_extcap(const char *extcap, char *output)
             if ( g_list_find(interface_keys, int_iter->call) )
             {
                 g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_WARNING, "Extcap interface \"%s\" is already provided by \"%s\" ",
-                      int_iter->call, (gchar *)extcap_if_executable(int_iter->call));
+                      int_iter->call, extcap_if_executable(int_iter->call));
                 walker = g_list_next(walker);
                 continue;
             }
@@ -1761,6 +1834,109 @@ process_new_extcap(const char *extcap, char *output)
 }
 
 
+/** Thread callback to save the output of a --extcap-config call. */
+static void
+extcap_process_config_cb(thread_pool_t *pool _U_, void *data, char *output)
+{
+    extcap_iface_info_t *iface_info = (extcap_iface_info_t *)data;
+    iface_info->output = output;
+}
+
+/**
+ * Thread callback to process discovered interfaces, scheduling more tasks to
+ * retrieve the configuration for each interface. Called once for every extcap
+ * program.
+ */
+static void
+extcap_process_interfaces_cb(thread_pool_t *pool, void *data, char *output)
+{
+    extcap_run_extcaps_info_t *info = (extcap_run_extcaps_info_t *)data;
+    guint i = 0;
+    guint num_interfaces = 0;
+
+    if (!output) {
+        // No interfaces available, nothing to do.
+        return;
+    }
+
+    // Save output for process_new_extcap.
+    info->output = output;
+
+    // Are there any interfaces to query information from?
+    GList *interfaces = extcap_parse_interfaces(output, NULL);
+    for (GList *iface = interfaces; iface; iface = g_list_next(iface)) {
+        extcap_interface *intf = (extcap_interface *)iface->data;
+        if (intf->if_type == EXTCAP_SENTENCE_INTERFACE) {
+            ++num_interfaces;
+        }
+    }
+    if (num_interfaces == 0) {
+        // nothing to do.
+        g_list_free_full(interfaces, extcap_free_interface);
+        return;
+    }
+
+    /* GSList is not thread-safe, so pre-allocate an array instead. */
+    info->iface_infos = g_new0(extcap_iface_info_t, num_interfaces);
+    info->num_interfaces = num_interfaces;
+
+    // Schedule new commands to retrieve the configuration.
+    for (GList *iface = interfaces; iface; iface = g_list_next(iface)) {
+        extcap_interface *intf = (extcap_interface *)iface->data;
+        if (intf->if_type != EXTCAP_SENTENCE_INTERFACE) {
+            continue;
+        }
+
+        const char *argv[] = {
+            EXTCAP_ARGUMENT_CONFIG,
+            EXTCAP_ARGUMENT_INTERFACE,
+            intf->call,
+            NULL
+        };
+        extcap_run_task_t *task = g_new0(extcap_run_task_t, 1);
+        extcap_iface_info_t *iface_info = &info->iface_infos[i++];
+
+        task->extcap_path = info->extcap_path;
+        task->argv = g_strdupv((char **)argv);
+        task->output_cb = extcap_process_config_cb;
+        task->data = iface_info;
+        iface_info->ifname = g_strdup(intf->call);
+
+        thread_pool_push(pool, task, NULL);
+    }
+    g_list_free_full(interfaces, extcap_free_interface);
+}
+
+/**
+ * Thread callback to check whether the new-style --list-interfaces call with an
+ * explicit function succeeded. If not, schedule a call without the new version
+ * argument.
+ */
+static void
+extcap_list_interfaces_cb(thread_pool_t *pool, void *data, char *output)
+{
+    extcap_run_extcaps_info_t *info = (extcap_run_extcaps_info_t *)data;
+
+    if (!output) {
+        /* No output available, schedule a fallback query. */
+        const char *argv[] = {
+            EXTCAP_ARGUMENT_LIST_INTERFACES,
+            NULL
+        };
+        extcap_run_task_t *task = g_new0(extcap_run_task_t, 1);
+
+        task->extcap_path = info->extcap_path;
+        task->argv = g_strdupv((char **)argv);
+        task->output_cb = extcap_process_interfaces_cb;
+        task->data = info;
+
+        thread_pool_push(pool, task, NULL);
+    } else {
+        extcap_process_interfaces_cb(pool, info, output);
+    }
+}
+
+
 /* Handles loading of the interfaces.
  *
  * A list of interfaces can be obtained by calling \ref extcap_loaded_interfaces
@@ -1788,12 +1964,11 @@ extcap_load_interface_list(void)
 
     if (_loaded_interfaces == NULL)
     {
-        GList * arguments = NULL;
-        GList * fallback = NULL;
         int major = 0;
         int minor = 0;
         guint count = 0;
-        extcap_output_info_t *infos;
+        extcap_run_extcaps_info_t *infos;
+        GList *unused_arguments = NULL;
 
         _loaded_interfaces = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, extcap_free_interface_info);
         /* Cleanup lookup table */
@@ -1805,19 +1980,42 @@ extcap_load_interface_list(void)
             _tool_for_ifname = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, g_free);
         }
 
-        arguments = g_list_append(arguments, g_strdup(EXTCAP_ARGUMENT_LIST_INTERFACES));
-        fallback = g_list_append(fallback, g_strdup(EXTCAP_ARGUMENT_LIST_INTERFACES));
-
         get_ws_version_number(&major, &minor, NULL);
-        arguments = g_list_append(arguments, g_strdup_printf("%s=%d.%d", EXTCAP_ARGUMENT_VERSION, major, minor));
-
-        infos = extcap_run_all(arguments, fallback, &count);
+        char *arg_version = g_strdup_printf("%s=%d.%d", EXTCAP_ARGUMENT_VERSION, major, minor);
+        const char *argv[] = {
+            EXTCAP_ARGUMENT_LIST_INTERFACES,
+            arg_version,
+            NULL
+        };
+        infos = (extcap_run_extcaps_info_t *)extcap_run_all(argv,
+                extcap_list_interfaces_cb, sizeof(extcap_run_extcaps_info_t),
+                &count);
         for (guint i = 0; i < count; i++) {
+            if (!infos[i].output) {
+                continue;
+            }
+
+            // Save new extcap and each discovered interface.
             process_new_extcap(infos[i].extcap_path, infos[i].output);
+            for (guint j = 0; j < infos[i].num_interfaces; j++) {
+                extcap_iface_info_t *iface_info = &infos[i].iface_infos[j];
+
+                if (!iface_info->output) {
+                    continue;
+                }
+
+                extcap_callback_info_t cb_info = {
+                    .ifname = iface_info->ifname,
+                    .output = iface_info->output,
+                    .data = &unused_arguments,
+                };
+                cb_preference(cb_info);
+            }
         }
-        extcap_free_output_info_array(infos, count);
-        g_list_free_full(fallback, g_free);
-        g_list_free_full(arguments, g_free);
+        /* XXX rework cb_preference such that this unused list can be removed. */
+        extcap_free_if_configuration(unused_arguments, TRUE);
+        extcap_free_extcaps_info_array(infos, count);
+        g_free(arg_version);
     }
 }