tools/lib/traceevent/event-plugin.c - third_party/linux - Git at Google

 /*
  * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation;
  * version 2.1 of the License (not later!)
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not,  see <http://www.gnu.org/licenses>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */

 #include <ctype.h>
 #include <stdio.h>
 #include <string.h>
 #include <dlfcn.h>
 #include <stdlib.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <dirent.h>
 #include "event-parse.h"
 #include "event-utils.h"

 #define LOCAL_PLUGIN_DIR ".traceevent/plugins"

 static struct registered_plugin_options {
 	struct registered_plugin_options	*next;
 	struct pevent_plugin_option		*options;
 } *registered_options;

 static struct trace_plugin_options {
 	struct trace_plugin_options	*next;
 	char				*plugin;
 	char				*option;
 	char				*value;
 } *trace_plugin_options;

 struct plugin_list {
 	struct plugin_list	*next;
 	char			*name;
 	void			*handle;
 };

 static void lower_case(char *str)
 {
 	if (!str)
 		return;
 	for (; *str; str++)
 		*str = tolower(*str);
 }

 static int update_option_value(struct pevent_plugin_option *op, const char *val)
 {
 	char *op_val;

 	if (!val) {
 		/* toggle, only if option is boolean */
 		if (op->value)
 			/* Warn? */
 			return 0;
 		op->set ^= 1;
 		return 0;
 	}

 	/*
 	 * If the option has a value then it takes a string
 	 * otherwise the option is a boolean.
 	 */
 	if (op->value) {
 		op->value = val;
 		return 0;
 	}

 	/* Option is boolean, must be either "1", "0", "true" or "false" */

 	op_val = strdup(val);
 	if (!op_val)
 		return -1;
 	lower_case(op_val);

 	if (strcmp(val, "1") == 0 || strcmp(val, "true") == 0)
 		op->set = 1;
 	else if (strcmp(val, "0") == 0 || strcmp(val, "false") == 0)
 		op->set = 0;
 	free(op_val);

 	return 0;
 }

 /**
  * traceevent_plugin_list_options - get list of plugin options
  *
  * Returns an array of char strings that list the currently registered
  * plugin options in the format of <plugin>:<option>. This list can be
  * used by toggling the option.
  *
  * Returns NULL if there's no options registered. On error it returns
  * INVALID_PLUGIN_LIST_OPTION
  *
  * Must be freed with traceevent_plugin_free_options_list().
  */
 char **traceevent_plugin_list_options(void)
 {
 	struct registered_plugin_options *reg;
 	struct pevent_plugin_option *op;
 	char **list = NULL;
 	char *name;
 	int count = 0;

 	for (reg = registered_options; reg; reg = reg->next) {
 		for (op = reg->options; op->name; op++) {
 			char *alias = op->plugin_alias ? op->plugin_alias : op->file;
 			char **temp = list;
 			int ret;

 			ret = asprintf(&name, "%s:%s", alias, op->name);
 			if (ret < 0)
 				goto err;

 			list = realloc(list, count + 2);
 			if (!list) {
 				list = temp;
 				free(name);
 				goto err;
 			}
 			list[count++] = name;
 			list[count] = NULL;
 		}
 	}
 	return list;

  err:
 	while (--count >= 0)
 		free(list[count]);
 	free(list);

 	return INVALID_PLUGIN_LIST_OPTION;
 }

 void traceevent_plugin_free_options_list(char **list)
 {
 	int i;

 	if (!list)
 		return;

 	if (list == INVALID_PLUGIN_LIST_OPTION)
 		return;

 	for (i = 0; list[i]; i++)
 		free(list[i]);

 	free(list);
 }

 static int
 update_option(const char *file, struct pevent_plugin_option *option)
 {
 	struct trace_plugin_options *op;
 	char *plugin;
 	int ret = 0;

 	if (option->plugin_alias) {
 		plugin = strdup(option->plugin_alias);
 		if (!plugin)
 			return -1;
 	} else {
 		char *p;
 		plugin = strdup(file);
 		if (!plugin)
 			return -1;
 		p = strstr(plugin, ".");
 		if (p)
 			*p = '\0';
 	}

 	/* first look for named options */
 	for (op = trace_plugin_options; op; op = op->next) {
 		if (!op->plugin)
 			continue;
 		if (strcmp(op->plugin, plugin) != 0)
 			continue;
 		if (strcmp(op->option, option->name) != 0)
 			continue;

 		ret = update_option_value(option, op->value);
 		if (ret)
 			goto out;
 		break;
 	}

 	/* first look for unnamed options */
 	for (op = trace_plugin_options; op; op = op->next) {
 		if (op->plugin)
 			continue;
 		if (strcmp(op->option, option->name) != 0)
 			continue;

 		ret = update_option_value(option, op->value);
 		break;
 	}

  out:
 	free(plugin);
 	return ret;
 }

 /**
  * traceevent_plugin_add_options - Add a set of options by a plugin
  * @name: The name of the plugin adding the options
  * @options: The set of options being loaded
  *
  * Sets the options with the values that have been added by user.
  */
 int traceevent_plugin_add_options(const char *name,
 				  struct pevent_plugin_option *options)
 {
 	struct registered_plugin_options *reg;

 	reg = malloc(sizeof(*reg));
 	if (!reg)
 		return -1;
 	reg->next = registered_options;
 	reg->options = options;
 	registered_options = reg;

 	while (options->name) {
 		update_option(name, options);
 		options++;
 	}
 	return 0;
 }

 /**
  * traceevent_plugin_remove_options - remove plugin options that were registered
  * @options: Options to removed that were registered with traceevent_plugin_add_options
  */
 void traceevent_plugin_remove_options(struct pevent_plugin_option *options)
 {
 	struct registered_plugin_options **last;
 	struct registered_plugin_options *reg;

 	for (last = &registered_options; *last; last = &(*last)->next) {
 		if ((*last)->options == options) {
 			reg = *last;
 			*last = reg->next;
 			free(reg);
 			return;
 		}
 	}
 }

 /**
  * traceevent_print_plugins - print out the list of plugins loaded
  * @s: the trace_seq descripter to write to
  * @prefix: The prefix string to add before listing the option name
  * @suffix: The suffix string ot append after the option name
  * @list: The list of plugins (usually returned by traceevent_load_plugins()
  *
  * Writes to the trace_seq @s the list of plugins (files) that is
  * returned by traceevent_load_plugins(). Use @prefix and @suffix for formating:
  * @prefix = "  ", @suffix = "\n".
  */
 void traceevent_print_plugins(struct trace_seq *s,
 			      const char *prefix, const char *suffix,
 			      const struct plugin_list *list)
 {
 	while (list) {
 		trace_seq_printf(s, "%s%s%s", prefix, list->name, suffix);
 		list = list->next;
 	}
 }

 static void
 load_plugin(struct pevent *pevent, const char *path,
 	    const char *file, void *data)
 {
 	struct plugin_list **plugin_list = data;
 	pevent_plugin_load_func func;
 	struct plugin_list *list;
 	const char *alias;
 	char *plugin;
 	void *handle;
 	int ret;

 	ret = asprintf(&plugin, "%s/%s", path, file);
 	if (ret < 0) {
 		warning("could not allocate plugin memory\n");
 		return;
 	}

 	handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
 	if (!handle) {
 		warning("could not load plugin '%s'\n%s\n",
 			plugin, dlerror());
 		goto out_free;
 	}

 	alias = dlsym(handle, PEVENT_PLUGIN_ALIAS_NAME);
 	if (!alias)
 		alias = file;

 	func = dlsym(handle, PEVENT_PLUGIN_LOADER_NAME);
 	if (!func) {
 		warning("could not find func '%s' in plugin '%s'\n%s\n",
 			PEVENT_PLUGIN_LOADER_NAME, plugin, dlerror());
 		goto out_free;
 	}

 	list = malloc(sizeof(*list));
 	if (!list) {
 		warning("could not allocate plugin memory\n");
 		goto out_free;
 	}

 	list->next = *plugin_list;
 	list->handle = handle;
 	list->name = plugin;
 	*plugin_list = list;

 	pr_stat("registering plugin: %s", plugin);
 	func(pevent);
 	return;

  out_free:
 	free(plugin);
 }

 static void
 load_plugins_dir(struct pevent *pevent, const char *suffix,
 		 const char *path,
 		 void (*load_plugin)(struct pevent *pevent,
 				     const char *path,
 				     const char *name,
 				     void *data),
 		 void *data)
 {
 	struct dirent *dent;
 	struct stat st;
 	DIR *dir;
 	int ret;

 	ret = stat(path, &st);
 	if (ret < 0)
 		return;

 	if (!S_ISDIR(st.st_mode))
 		return;

 	dir = opendir(path);
 	if (!dir)
 		return;

 	while ((dent = readdir(dir))) {
 		const char *name = dent->d_name;

 		if (strcmp(name, ".") == 0 ||
 		    strcmp(name, "..") == 0)
 			continue;

 		/* Only load plugins that end in suffix */
 		if (strcmp(name + (strlen(name) - strlen(suffix)), suffix) != 0)
 			continue;

 		load_plugin(pevent, path, name, data);
 	}

 	closedir(dir);
 }

 static void
 load_plugins(struct pevent *pevent, const char *suffix,
 	     void (*load_plugin)(struct pevent *pevent,
 				 const char *path,
 				 const char *name,
 				 void *data),
 	     void *data)
 {
 	char *home;
 	char *path;
 	char *envdir;
 	int ret;

 	if (pevent->flags & PEVENT_DISABLE_PLUGINS)
 		return;

 	/*
 	 * If a system plugin directory was defined,
 	 * check that first.
 	 */
 #ifdef PLUGIN_DIR
 	if (!(pevent->flags & PEVENT_DISABLE_SYS_PLUGINS))
 		load_plugins_dir(pevent, suffix, PLUGIN_DIR,
 				 load_plugin, data);
 #endif

 	/*
 	 * Next let the environment-set plugin directory
 	 * override the system defaults.
 	 */
 	envdir = getenv("TRACEEVENT_PLUGIN_DIR");
 	if (envdir)
 		load_plugins_dir(pevent, suffix, envdir, load_plugin, data);

 	/*
 	 * Now let the home directory override the environment
 	 * or system defaults.
 	 */
 	home = getenv("HOME");
 	if (!home)
 		return;

 	ret = asprintf(&path, "%s/%s", home, LOCAL_PLUGIN_DIR);
 	if (ret < 0) {
 		warning("could not allocate plugin memory\n");
 		return;
 	}

 	load_plugins_dir(pevent, suffix, path, load_plugin, data);

 	free(path);
 }

 struct plugin_list*
 traceevent_load_plugins(struct pevent *pevent)
 {
 	struct plugin_list *list = NULL;

 	load_plugins(pevent, ".so", load_plugin, &list);
 	return list;
 }

 void
 traceevent_unload_plugins(struct plugin_list *plugin_list, struct pevent *pevent)
 {
 	pevent_plugin_unload_func func;
 	struct plugin_list *list;

 	while (plugin_list) {
 		list = plugin_list;
 		plugin_list = list->next;
 		func = dlsym(list->handle, PEVENT_PLUGIN_UNLOADER_NAME);
 		if (func)
 			func(pevent);
 		dlclose(list->handle);
 		free(list->name);
 		free(list);
 	}
 }
	/*
	* Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation;
	* version 2.1 of the License (not later!)
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this program; if not, see <http://www.gnu.org/licenses>
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/

	#include <ctype.h>
	#include <stdio.h>
	#include <string.h>
	#include <dlfcn.h>
	#include <stdlib.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <dirent.h>
	#include "event-parse.h"
	#include "event-utils.h"

	#define LOCAL_PLUGIN_DIR ".traceevent/plugins"

	static struct registered_plugin_options {
	struct registered_plugin_options *next;
	struct pevent_plugin_option *options;
	} *registered_options;

	static struct trace_plugin_options {
	struct trace_plugin_options *next;
	char *plugin;
	char *option;
	char *value;
	} *trace_plugin_options;

	struct plugin_list {
	struct plugin_list *next;
	char *name;
	void *handle;
	};

	static void lower_case(char *str)
	{
	if (!str)
	return;
	for (; *str; str++)
	str = tolower(str);
	}

	static int update_option_value(struct pevent_plugin_option op, const char val)
	{
	char *op_val;

	if (!val) {
	/* toggle, only if option is boolean */
	if (op->value)
	/* Warn? */
	return 0;
	op->set ^= 1;
	return 0;
	}

	/*
	* If the option has a value then it takes a string
	* otherwise the option is a boolean.
	*/
	if (op->value) {
	op->value = val;
	return 0;
	}

	/* Option is boolean, must be either "1", "0", "true" or "false" */

	op_val = strdup(val);
	if (!op_val)
	return -1;
	lower_case(op_val);

	if (strcmp(val, "1") == 0 \|\| strcmp(val, "true") == 0)
	op->set = 1;
	else if (strcmp(val, "0") == 0 \|\| strcmp(val, "false") == 0)
	op->set = 0;
	free(op_val);

	return 0;
	}

	/**
	* traceevent_plugin_list_options - get list of plugin options
	*
	* Returns an array of char strings that list the currently registered
	* plugin options in the format of <plugin>:<option>. This list can be
	* used by toggling the option.
	*
	* Returns NULL if there's no options registered. On error it returns
	* INVALID_PLUGIN_LIST_OPTION
	*
	* Must be freed with traceevent_plugin_free_options_list().
	*/
	char **traceevent_plugin_list_options(void)
	{
	struct registered_plugin_options *reg;
	struct pevent_plugin_option *op;
	char **list = NULL;
	char *name;
	int count = 0;

	for (reg = registered_options; reg; reg = reg->next) {
	for (op = reg->options; op->name; op++) {
	char *alias = op->plugin_alias ? op->plugin_alias : op->file;
	char **temp = list;
	int ret;

	ret = asprintf(&name, "%s:%s", alias, op->name);
	if (ret < 0)
	goto err;

	list = realloc(list, count + 2);
	if (!list) {
	list = temp;
	free(name);
	goto err;
	}
	list[count++] = name;
	list[count] = NULL;
	}
	}
	return list;

	err:
	while (--count >= 0)
	free(list[count]);
	free(list);

	return INVALID_PLUGIN_LIST_OPTION;
	}

	void traceevent_plugin_free_options_list(char **list)
	{
	int i;

	if (!list)
	return;

	if (list == INVALID_PLUGIN_LIST_OPTION)
	return;

	for (i = 0; list[i]; i++)
	free(list[i]);

	free(list);
	}

	static int
	update_option(const char file, struct pevent_plugin_option option)
	{
	struct trace_plugin_options *op;
	char *plugin;
	int ret = 0;

	if (option->plugin_alias) {
	plugin = strdup(option->plugin_alias);
	if (!plugin)
	return -1;
	} else {
	char *p;
	plugin = strdup(file);
	if (!plugin)
	return -1;
	p = strstr(plugin, ".");
	if (p)
	*p = '\0';
	}

	/* first look for named options */
	for (op = trace_plugin_options; op; op = op->next) {
	if (!op->plugin)
	continue;
	if (strcmp(op->plugin, plugin) != 0)
	continue;
	if (strcmp(op->option, option->name) != 0)
	continue;

	ret = update_option_value(option, op->value);
	if (ret)
	goto out;
	break;
	}

	/* first look for unnamed options */
	for (op = trace_plugin_options; op; op = op->next) {
	if (op->plugin)
	continue;
	if (strcmp(op->option, option->name) != 0)
	continue;

	ret = update_option_value(option, op->value);
	break;
	}

	out:
	free(plugin);
	return ret;
	}

	/**
	* traceevent_plugin_add_options - Add a set of options by a plugin
	* @name: The name of the plugin adding the options
	* @options: The set of options being loaded
	*
	* Sets the options with the values that have been added by user.
	*/
	int traceevent_plugin_add_options(const char *name,
	struct pevent_plugin_option *options)
	{
	struct registered_plugin_options *reg;

	reg = malloc(sizeof(*reg));
	if (!reg)
	return -1;
	reg->next = registered_options;
	reg->options = options;
	registered_options = reg;

	while (options->name) {
	update_option(name, options);
	options++;
	}
	return 0;
	}

	/**
	* traceevent_plugin_remove_options - remove plugin options that were registered
	* @options: Options to removed that were registered with traceevent_plugin_add_options
	*/
	void traceevent_plugin_remove_options(struct pevent_plugin_option *options)
	{
	struct registered_plugin_options **last;
	struct registered_plugin_options *reg;

	for (last = &registered_options; last; last = &(last)->next) {
	if ((*last)->options == options) {
	reg = *last;
	*last = reg->next;
	free(reg);
	return;
	}
	}
	}

	/**
	* traceevent_print_plugins - print out the list of plugins loaded
	* @s: the trace_seq descripter to write to
	* @prefix: The prefix string to add before listing the option name
	* @suffix: The suffix string ot append after the option name
	* @list: The list of plugins (usually returned by traceevent_load_plugins()
	*
	* Writes to the trace_seq @s the list of plugins (files) that is
	* returned by traceevent_load_plugins(). Use @prefix and @suffix for formating:
	* @prefix = " ", @suffix = "\n".
	*/
	void traceevent_print_plugins(struct trace_seq *s,
	const char prefix, const char suffix,
	const struct plugin_list *list)
	{
	while (list) {
	trace_seq_printf(s, "%s%s%s", prefix, list->name, suffix);
	list = list->next;
	}
	}

	static void
	load_plugin(struct pevent pevent, const char path,
	const char file, void data)
	{
	struct plugin_list **plugin_list = data;
	pevent_plugin_load_func func;
	struct plugin_list *list;
	const char *alias;
	char *plugin;
	void *handle;
	int ret;

	ret = asprintf(&plugin, "%s/%s", path, file);
	if (ret < 0) {
	warning("could not allocate plugin memory\n");
	return;
	}

	handle = dlopen(plugin, RTLD_NOW \| RTLD_GLOBAL);
	if (!handle) {
	warning("could not load plugin '%s'\n%s\n",
	plugin, dlerror());
	goto out_free;
	}

	alias = dlsym(handle, PEVENT_PLUGIN_ALIAS_NAME);
	if (!alias)
	alias = file;

	func = dlsym(handle, PEVENT_PLUGIN_LOADER_NAME);
	if (!func) {
	warning("could not find func '%s' in plugin '%s'\n%s\n",
	PEVENT_PLUGIN_LOADER_NAME, plugin, dlerror());
	goto out_free;
	}

	list = malloc(sizeof(*list));
	if (!list) {
	warning("could not allocate plugin memory\n");
	goto out_free;
	}

	list->next = *plugin_list;
	list->handle = handle;
	list->name = plugin;
	*plugin_list = list;

	pr_stat("registering plugin: %s", plugin);
	func(pevent);
	return;

	out_free:
	free(plugin);
	}

	static void
	load_plugins_dir(struct pevent pevent, const char suffix,
	const char *path,
	void (load_plugin)(struct pevent pevent,
	const char *path,
	const char *name,
	void *data),
	void *data)
	{
	struct dirent *dent;
	struct stat st;
	DIR *dir;
	int ret;

	ret = stat(path, &st);
	if (ret < 0)
	return;

	if (!S_ISDIR(st.st_mode))
	return;

	dir = opendir(path);
	if (!dir)
	return;

	while ((dent = readdir(dir))) {
	const char *name = dent->d_name;

	if (strcmp(name, ".") == 0 \|\|
	strcmp(name, "..") == 0)
	continue;

	/* Only load plugins that end in suffix */
	if (strcmp(name + (strlen(name) - strlen(suffix)), suffix) != 0)
	continue;

	load_plugin(pevent, path, name, data);
	}

	closedir(dir);
	}

	static void
	load_plugins(struct pevent pevent, const char suffix,
	void (load_plugin)(struct pevent pevent,
	const char *path,
	const char *name,
	void *data),
	void *data)
	{
	char *home;
	char *path;
	char *envdir;
	int ret;

	if (pevent->flags & PEVENT_DISABLE_PLUGINS)
	return;

	/*
	* If a system plugin directory was defined,
	* check that first.
	*/
	#ifdef PLUGIN_DIR
	if (!(pevent->flags & PEVENT_DISABLE_SYS_PLUGINS))
	load_plugins_dir(pevent, suffix, PLUGIN_DIR,
	load_plugin, data);
	#endif

	/*
	* Next let the environment-set plugin directory
	* override the system defaults.
	*/
	envdir = getenv("TRACEEVENT_PLUGIN_DIR");
	if (envdir)
	load_plugins_dir(pevent, suffix, envdir, load_plugin, data);

	/*
	* Now let the home directory override the environment
	* or system defaults.
	*/
	home = getenv("HOME");
	if (!home)
	return;

	ret = asprintf(&path, "%s/%s", home, LOCAL_PLUGIN_DIR);
	if (ret < 0) {
	warning("could not allocate plugin memory\n");
	return;
	}

	load_plugins_dir(pevent, suffix, path, load_plugin, data);

	free(path);
	}

	struct plugin_list*
	traceevent_load_plugins(struct pevent *pevent)
	{
	struct plugin_list *list = NULL;

	load_plugins(pevent, ".so", load_plugin, &list);
	return list;
	}

	void
	traceevent_unload_plugins(struct plugin_list plugin_list, struct pevent pevent)
	{
	pevent_plugin_unload_func func;
	struct plugin_list *list;

	while (plugin_list) {
	list = plugin_list;
	plugin_list = list->next;
	func = dlsym(list->handle, PEVENT_PLUGIN_UNLOADER_NAME);
	if (func)
	func(pevent);
	dlclose(list->handle);
	free(list->name);
	free(list);
	}
	}