Add bt_version_get_*() functions to dynamically get the lib's version

[babeltrace.git] / lib / plugin / plugin.c

/*
 * plugin.c
 *
 * Babeltrace Plugin (generic)
 *
 * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 * Copyright 2017 Philippe Proulx <pproulx@efficios.com>
 *
 * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <babeltrace/babeltrace-internal.h>
#include <babeltrace/compiler.h>
#include <babeltrace/ref.h>
#include <babeltrace/common-internal.h>
#include <babeltrace/plugin/plugin-internal.h>
#include <babeltrace/plugin/plugin-so-internal.h>
#include <glib.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <dirent.h>

#define PYTHON_PLUGIN_PROVIDER_FILENAME	"libbabeltrace-python-plugin-provider." G_MODULE_SUFFIX
#define PYTHON_PLUGIN_PROVIDER_SYM_NAME	bt_plugin_python_create_all_from_file
#define PYTHON_PLUGIN_PROVIDER_SYM_NAME_STR	TOSTRING(PYTHON_PLUGIN_PROVIDER_SYM_NAME)

#ifdef BT_BUILT_IN_PYTHON_PLUGIN_SUPPORT
#include <babeltrace/plugin/python-plugin-provider-internal.h>
static
struct bt_plugin **(*bt_plugin_python_create_all_from_file_sym)(const char *path) =
	bt_plugin_python_create_all_from_file;
#else /* BT_BUILT_IN_PYTHON_PLUGIN_SUPPORT */
static GModule *python_plugin_provider_module;
static
struct bt_plugin **(*bt_plugin_python_create_all_from_file_sym)(const char *path);

__attribute__((constructor)) static
void init_python_plugin_provider(void) {
	python_plugin_provider_module =
		g_module_open(PYTHON_PLUGIN_PROVIDER_FILENAME,
			G_MODULE_BIND_LOCAL);
	if (!python_plugin_provider_module) {
		printf_warning("Cannot find `%s`: Python plugin support is disabled\n",
			PYTHON_PLUGIN_PROVIDER_FILENAME);
		return;
	}

	if (!g_module_symbol(python_plugin_provider_module,
			PYTHON_PLUGIN_PROVIDER_SYM_NAME_STR,
			(gpointer) &bt_plugin_python_create_all_from_file_sym)) {
		printf_warning("Cannot find the Python plugin provider loading symbole: Python plugin support is disabled\n");
	}
}

__attribute__((destructor)) static
void fini_python_plugin_provider(void) {
	if (python_plugin_provider_module) {
		(void) g_module_close(python_plugin_provider_module);
		python_plugin_provider_module = NULL;
	}
}
#endif

struct bt_plugin **bt_plugin_create_all_from_static(void)
{
	return bt_plugin_so_create_all_from_static();
}

struct bt_plugin **bt_plugin_create_all_from_file(const char *path)
{
	struct bt_plugin **plugins = NULL;

	if (!path) {
		goto end;
	}

	printf_verbose("Trying to load plugins from `%s`\n", path);

	/* Try shared object plugins */
	plugins = bt_plugin_so_create_all_from_file(path);
	if (plugins) {
		goto end;
	}

	/* Try Python plugins if support is available */
	if (bt_plugin_python_create_all_from_file_sym) {
		plugins = bt_plugin_python_create_all_from_file_sym(path);
		if (plugins) {
			goto end;
		}
	}

end:
	return plugins;
}

static void destroy_gstring(void *data)
{
	g_string_free(data, TRUE);
}

void free_plugins(struct bt_plugin **plugins) {
	if (plugins) {
		struct bt_plugin **cur_plugin = plugins;

		while (*cur_plugin) {
			bt_put(*cur_plugin);
			cur_plugin++;
		}

		free(plugins);
	}
}

struct bt_plugin *bt_plugin_create_from_name(const char *plugin_name)
{
	const char *system_plugin_dir;
	char *home_plugin_dir = NULL;
	const char *envvar;
	struct bt_plugin *plugin = NULL;
	struct bt_plugin **plugins = NULL;
	struct bt_plugin **cur_plugin;
	GPtrArray *dirs = NULL;
	int ret;
	size_t i;

	if (!plugin_name) {
		goto end;
	}

	dirs = g_ptr_array_new_with_free_func((GDestroyNotify) destroy_gstring);
	if (!dirs) {
		goto end;
	}

	/*
	 * Search order is:
	 *
	 * 1. BABELTRACE_PLUGIN_PATH environment variable
	 *    (colon-separated list of directories)
	 * 2. ~/.local/lib/babeltrace/plugins
	 * 3. Default system directory for Babeltrace plugins, usually
	 *    /usr/lib/babeltrace/plugins or
	 *    /usr/local/lib/babeltrace/plugins if installed
	 *    locally
	 * 4. Built-in plugins (static)
	 *
	 * Directories are searched non-recursively.
	 */
	envvar = getenv("BABELTRACE_PLUGIN_PATH");
	if (envvar) {
		ret = bt_common_append_plugin_path_dirs(envvar, dirs);
		if (ret) {
			goto end;
		}
	}

	home_plugin_dir = bt_common_get_home_plugin_path();
	if (home_plugin_dir) {
		GString *home_plugin_dir_str =
			g_string_new(home_plugin_dir);

		if (!home_plugin_dir_str) {
			goto end;
		}

		g_ptr_array_add(dirs, home_plugin_dir_str);
	}

	system_plugin_dir = bt_common_get_system_plugin_path();
	if (system_plugin_dir) {
		GString *system_plugin_dir_str =
			g_string_new(system_plugin_dir);

		if (!system_plugin_dir_str) {
			goto end;
		}

		g_ptr_array_add(dirs, system_plugin_dir_str);
	}

	for (i = 0; i < dirs->len; i++) {
		GString *dir = g_ptr_array_index(dirs, i);

		printf_verbose("Trying to load plugins from directory `%s`\n",
			dir->str);
		free_plugins(plugins);
		plugins = bt_plugin_create_all_from_dir(dir->str, false);
		if (!plugins) {
			continue;
		}

		cur_plugin = plugins;

		while (*cur_plugin) {
			if (strcmp(bt_plugin_get_name(*cur_plugin), plugin_name)
					== 0) {
				plugin = bt_get(*cur_plugin);
				goto end;
			}

			cur_plugin++;
		}
	}

	free_plugins(plugins);
	plugins = bt_plugin_create_all_from_static();
	cur_plugin = plugins;

	while (*cur_plugin) {
		if (strcmp(bt_plugin_get_name(*cur_plugin), plugin_name) == 0) {
			plugin = bt_get(*cur_plugin);
			goto end;
		}

		cur_plugin++;
	}

end:
	free(home_plugin_dir);
	free_plugins(plugins);

	if (dirs) {
		g_ptr_array_free(dirs, TRUE);
	}

	return plugin;
}

/* Allocate dirent as recommended by READDIR(3), NOTES on readdir_r */
static
struct dirent *alloc_dirent(const char *path)
{
	size_t len;
	long name_max;
	struct dirent *entry;

	name_max = pathconf(path, _PC_NAME_MAX);
	if (name_max == -1) {
		name_max = PATH_MAX;
	}
	len = offsetof(struct dirent, d_name) + name_max + 1;
	entry = zmalloc(len);
	return entry;
}

static
enum bt_plugin_status bt_plugin_create_append_all_from_dir(
		GPtrArray *plugins, const char *path, bool recurse)
{
	DIR *directory = NULL;
	struct dirent *entry = NULL, *result = NULL;
	char *file_path = NULL;
	size_t path_len;
	enum bt_plugin_status ret = BT_PLUGIN_STATUS_OK;

	if (!path) {
		ret = BT_PLUGIN_STATUS_ERROR;
		goto end;
	}

	path_len = strlen(path);

	if (path_len >= PATH_MAX) {
		ret = BT_PLUGIN_STATUS_ERROR;
		goto end;
	}

	entry = alloc_dirent(path);
	if (!entry) {
		ret = BT_PLUGIN_STATUS_ERROR;
		goto end;
	}

	file_path = zmalloc(PATH_MAX);
	if (!file_path) {
		ret = BT_PLUGIN_STATUS_NOMEM;
		goto end;
	}

	strncpy(file_path, path, path_len);
	/* Append a trailing '/' to the path */
	if (file_path[path_len - 1] != '/') {
		file_path[path_len++] = '/';
	}

	directory = opendir(file_path);
	if (!directory) {
		perror("Failed to open plug-in directory");
		ret = BT_PLUGIN_STATUS_ERROR;
		goto end;
	}

	/* Recursively walk directory */
	while (!readdir_r(directory, entry, &result) && result) {
		struct stat st;
		int stat_ret;
		size_t file_name_len;

		if (result->d_name[0] == '.') {
			/* Skip hidden files, . and .. */
			continue;
		}

		file_name_len = strlen(result->d_name);

		if (path_len + file_name_len >= PATH_MAX) {
			continue;
		}

		strncpy(file_path + path_len, result->d_name, file_name_len);
		file_path[path_len + file_name_len] = '\0';
		stat_ret = stat(file_path, &st);
		if (stat_ret < 0) {
			/* Continue to next file / directory. */
			printf_perror("Failed to stat() plugin file\n");
			continue;
		}

		if (S_ISDIR(st.st_mode) && recurse) {
			ret = bt_plugin_create_append_all_from_dir(plugins,
				file_path, true);
			if (ret < 0) {
				goto end;
			}
		} else if (S_ISREG(st.st_mode)) {
			struct bt_plugin **plugins_from_file =
				bt_plugin_create_all_from_file(file_path);

			if (plugins_from_file) {
				struct bt_plugin **plugin;

				for (plugin = plugins_from_file; *plugin; plugin++) {
					/* Transfer ownership to array */
					g_ptr_array_add(plugins, *plugin);
				}

				free(plugins_from_file);
			}
		}
	}
end:
	if (directory) {
		if (closedir(directory)) {
			/*
			 * We don't want to override the error since there is
			 * nothing could do.
			 */
		        perror("Failed to close plug-in directory");
		}
	}
	free(entry);
	free(file_path);
	return ret;
}

struct bt_plugin **bt_plugin_create_all_from_dir(const char *path,
		bool recurse)
{
	GPtrArray *plugins_array = g_ptr_array_new();
	struct bt_plugin **plugins = NULL;
	enum bt_plugin_status status;

	/* Append found plugins to array */
	status = bt_plugin_create_append_all_from_dir(plugins_array, path,
		recurse);
	if (status < 0) {
		goto error;
	}

	/* Add sentinel to array */
	g_ptr_array_add(plugins_array, NULL);
	plugins = (struct bt_plugin **) plugins_array->pdata;
	goto end;

error:
	if (plugins_array) {
		g_ptr_array_free(plugins_array, TRUE);
		plugins_array = NULL;
	}

end:
	if (plugins_array) {
		g_ptr_array_free(plugins_array, FALSE);
	}

	return plugins;
}

const char *bt_plugin_get_name(struct bt_plugin *plugin)
{
	return plugin && plugin->info.name_set ? plugin->info.name->str : NULL;
}

const char *bt_plugin_get_author(struct bt_plugin *plugin)
{
	return plugin && plugin->info.author_set ? plugin->info.author->str : NULL;
}

const char *bt_plugin_get_license(struct bt_plugin *plugin)
{
	return plugin && plugin->info.license_set ? plugin->info.license->str : NULL;
}

const char *bt_plugin_get_path(struct bt_plugin *plugin)
{
	return plugin && plugin->info.path_set ? plugin->info.path->str : NULL;
}

const char *bt_plugin_get_description(struct bt_plugin *plugin)
{
	return plugin && plugin->info.description_set ? plugin->info.description->str : NULL;
}

enum bt_plugin_status bt_plugin_get_version(struct bt_plugin *plugin,
		unsigned int *major, unsigned int *minor, unsigned int *patch,
		const char **extra)
{
	enum bt_plugin_status status = BT_PLUGIN_STATUS_OK;

	if (!plugin || !plugin->info.version_set) {
		status = BT_PLUGIN_STATUS_ERROR;
		goto end;
	}

	if (major) {
		*major = plugin->info.version.major;
	}

	if (minor) {
		*minor = plugin->info.version.minor;
	}

	if (patch) {
		*patch = plugin->info.version.patch;
	}

	if (extra) {
		*extra = plugin->info.version.extra->str;
	}

end:
	return status;
}

int bt_plugin_get_component_class_count(struct bt_plugin *plugin)
{
	return plugin ? plugin->comp_classes->len : -1;
}

struct bt_component_class *bt_plugin_get_component_class(
		struct bt_plugin *plugin, size_t index)
{
	struct bt_component_class *comp_class = NULL;

	if (!plugin || index >= plugin->comp_classes->len) {
		goto error;
	}

	comp_class = g_ptr_array_index(plugin->comp_classes, index);
	bt_get(comp_class);
	goto end;

error:
	BT_PUT(comp_class);

end:
	return comp_class;
}

struct bt_component_class *bt_plugin_get_component_class_by_name_and_type(
		struct bt_plugin *plugin, const char *name,
		enum bt_component_class_type type)
{
	struct bt_component_class *comp_class = NULL;
	size_t i;

	if (!plugin || !name) {
		goto error;
	}

	for (i = 0; i < plugin->comp_classes->len; i++) {
		struct bt_component_class *comp_class_candidate =
			g_ptr_array_index(plugin->comp_classes, i);
		const char *comp_class_cand_name =
			bt_component_class_get_name(comp_class_candidate);
		enum bt_component_class_type comp_class_cand_type =
			bt_component_class_get_type(comp_class_candidate);

		assert(comp_class_cand_name);
		assert(comp_class_cand_type >= 0);

		if (strcmp(name, comp_class_cand_name) == 0 &&
				comp_class_cand_type == type) {
			comp_class = bt_get(comp_class_candidate);
			break;
		}
	}

	goto end;

error:
	BT_PUT(comp_class);

end:
	return comp_class;
}

enum bt_plugin_status bt_plugin_add_component_class(
	struct bt_plugin *plugin, struct bt_component_class *comp_class)
{
	enum bt_plugin_status status = BT_PLUGIN_STATUS_OK;
	struct bt_component_class *comp_class_dup = NULL;
	int ret;
	int comp_class_index = -1;

	if (!plugin || !comp_class || plugin->frozen) {
		goto error;
	}

	/* Check for duplicate */
	comp_class_dup = bt_plugin_get_component_class_by_name_and_type(plugin,
		bt_component_class_get_name(comp_class),
		bt_component_class_get_type(comp_class));
	if (comp_class_dup) {
		printf_verbose("Plugin `%s`: adding component class with existing name `%s` and type %d\n",
			bt_plugin_get_name(plugin),
			bt_component_class_get_name(comp_class),
			bt_component_class_get_type(comp_class));
		goto error;
	}

	/* Add new component class */
	comp_class_index = plugin->comp_classes->len;
	g_ptr_array_add(plugin->comp_classes, bt_get(comp_class));

	/* Special case for a shared object plugin */
	if (plugin->type == BT_PLUGIN_TYPE_SO) {
		ret = bt_plugin_so_on_add_component_class(plugin, comp_class);
		if (ret) {
			goto error;
		}
	}

	goto end;

error:
	/* Remove entry from plugin's component classes (if added) */
	if (comp_class_index >= 0) {
		g_ptr_array_remove_index(plugin->comp_classes,
			comp_class_index);
	}

	status = BT_PLUGIN_STATUS_ERROR;

end:
	bt_put(comp_class_dup);
	return status;
}