1 files changed, 711 insertions, 0 deletions

diff --git a/src/event-plugin.c b/src/event-plugin.c
new file mode 100644
index 0000000..f42243f
--- /dev/null
+++ b/src/event-plugin.c
@@ -0,0 +1,711 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+
+#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 <errno.h>
+#include "event-parse.h"
+#include "event-parse-local.h"
+#include "event-utils.h"
+#include "trace-seq.h"
+
+#define LOCAL_PLUGIN_DIR ".local/lib/traceevent/plugins/"
+
+static struct registered_plugin_options {
+	struct registered_plugin_options	*next;
+	struct tep_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 tep_plugin_list {
+	struct tep_plugin_list	*next;
+	char			*name;
+	void			*handle;
+};
+
+struct tep_plugins_dir {
+	struct tep_plugins_dir		*next;
+	char				*path;
+	enum tep_plugin_load_priority	prio;
+};
+
+static void lower_case(char *str)
+{
+	if (!str)
+		return;
+	for (; *str; str++)
+		*str = tolower(*str);
+}
+
+static int update_option_value(struct tep_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;
+}
+
+/**
+ * tep_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 tep_plugin_free_options_list().
+ */
+char **tep_plugin_list_options(void)
+{
+	struct registered_plugin_options *reg;
+	struct tep_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 tep_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 tep_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;
+}
+
+/**
+ * tep_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 tep_plugin_add_options(const char *name,
+			   struct tep_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;
+}
+
+/**
+ * tep_plugin_remove_options - remove plugin options that were registered
+ * @options: Options to removed that were registered with tep_plugin_add_options
+ */
+void tep_plugin_remove_options(struct tep_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;
+		}
+	}
+}
+
+static int parse_option_name(char **option, char **plugin)
+{
+	char *p;
+
+	*plugin = NULL;
+
+	if ((p = strstr(*option, ":"))) {
+		*plugin = *option;
+		*p = '\0';
+		*option = strdup(p + 1);
+		if (!*option)
+			return -1;
+	}
+	return 0;
+}
+
+static struct tep_plugin_option *
+find_registered_option(const char *plugin, const char *option)
+{
+	struct registered_plugin_options *reg;
+	struct tep_plugin_option *op;
+	const char *op_plugin;
+
+	for (reg = registered_options; reg; reg = reg->next) {
+		for (op = reg->options; op->name; op++) {
+			if (op->plugin_alias)
+				op_plugin = op->plugin_alias;
+			else
+				op_plugin = op->file;
+
+			if (plugin && strcmp(plugin, op_plugin) != 0)
+				continue;
+			if (strcmp(option, op->name) != 0)
+				continue;
+
+			return op;
+		}
+	}
+
+	return NULL;
+}
+
+static int process_option(const char *plugin, const char *option, const char *val)
+{
+	struct tep_plugin_option *op;
+
+	op = find_registered_option(plugin, option);
+	if (!op)
+		return 0;
+
+	return update_option_value(op, val);
+}
+
+/**
+ * tep_plugin_add_option - add an option/val pair to set plugin options
+ * @name: The name of the option (format: <plugin>:<option> or just <option>)
+ * @val: (optional) the value for the option
+ *
+ * Modify a plugin option. If @val is given than the value of the option
+ * is set (note, some options just take a boolean, so @val must be either
+ * "1" or "0" or "true" or "false").
+ */
+int tep_plugin_add_option(const char *name, const char *val)
+{
+	struct trace_plugin_options *op;
+	char *option_str;
+	char *plugin;
+
+	option_str = strdup(name);
+	if (!option_str)
+		return -ENOMEM;
+
+	if (parse_option_name(&option_str, &plugin) < 0)
+		return -ENOMEM;
+
+	/* If the option exists, update the val */
+	for (op = trace_plugin_options; op; op = op->next) {
+		/* Both must be NULL or not NULL */
+		if ((!plugin || !op->plugin) && plugin != op->plugin)
+			continue;
+		if (plugin && strcmp(plugin, op->plugin) != 0)
+			continue;
+		if (strcmp(op->option, option_str) != 0)
+			continue;
+
+		/* update option */
+		free(op->value);
+		if (val) {
+			op->value = strdup(val);
+			if (!op->value)
+				goto out_free;
+		} else
+			op->value = NULL;
+
+		/* plugin and option_str don't get freed at the end */
+		free(plugin);
+		free(option_str);
+
+		plugin = op->plugin;
+		option_str = op->option;
+		break;
+	}
+
+	/* If not found, create */
+	if (!op) {
+		op = malloc(sizeof(*op));
+		if (!op)
+			goto out_free;
+		memset(op, 0, sizeof(*op));
+		op->plugin = plugin;
+		op->option = option_str;
+		if (val) {
+			op->value = strdup(val);
+			if (!op->value) {
+				free(op);
+				goto out_free;
+			}
+		}
+		op->next = trace_plugin_options;
+		trace_plugin_options = op;
+	}
+
+	return process_option(plugin, option_str, val);
+
+out_free:
+	free(plugin);
+	free(option_str);
+	return -ENOMEM;
+}
+
+static void print_op_data(struct trace_seq *s, const char *name,
+			  const char *op)
+{
+	if (op)
+		trace_seq_printf(s, "%8s:\t%s\n", name, op);
+}
+
+/**
+ * tep_plugin_print_options - print out the registered plugin options
+ * @s: The trace_seq descriptor to write the plugin options into
+ *
+ * Writes a list of options into trace_seq @s.
+ */
+void tep_plugin_print_options(struct trace_seq *s)
+{
+	struct registered_plugin_options *reg;
+	struct tep_plugin_option *op;
+
+	for (reg = registered_options; reg; reg = reg->next) {
+		if (reg != registered_options)
+			trace_seq_printf(s, "============\n");
+		for (op = reg->options; op->name; op++) {
+			if (op != reg->options)
+				trace_seq_printf(s, "------------\n");
+			print_op_data(s, "file", op->file);
+			print_op_data(s, "plugin", op->plugin_alias);
+			print_op_data(s, "option", op->name);
+			print_op_data(s, "desc", op->description);
+			print_op_data(s, "value", op->value);
+			trace_seq_printf(s, "%8s:\t%d\n", "set", op->set);
+		}
+	}
+}
+
+/**
+ * tep_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 tep_load_plugins()
+ *
+ * Writes to the trace_seq @s the list of plugins (files) that is
+ * returned by tep_load_plugins(). Use @prefix and @suffix for formating:
+ * @prefix = "  ", @suffix = "\n".
+ */
+void tep_print_plugins(struct trace_seq *s,
+		       const char *prefix, const char *suffix,
+		       const struct tep_plugin_list *list)
+{
+	while (list) {
+		trace_seq_printf(s, "%s%s%s", prefix, list->name, suffix);
+		list = list->next;
+	}
+}
+
+static void
+load_plugin(struct tep_handle *tep, const char *path,
+	    const char *file, void *data)
+{
+	struct tep_plugin_list **plugin_list = data;
+	struct tep_plugin_option *options;
+	tep_plugin_load_func func;
+	struct tep_plugin_list *list;
+	const char *alias;
+	char *plugin;
+	void *handle;
+	int ret;
+
+	ret = asprintf(&plugin, "%s/%s", path, file);
+	if (ret < 0) {
+		tep_warning("could not allocate plugin memory\n");
+		return;
+	}
+
+	handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
+	if (!handle) {
+		tep_warning("could not load plugin '%s'\n%s\n",
+			    plugin, dlerror());
+		goto out_free;
+	}
+
+	alias = dlsym(handle, TEP_PLUGIN_ALIAS_NAME);
+	if (!alias)
+		alias = file;
+
+	options = dlsym(handle, TEP_PLUGIN_OPTIONS_NAME);
+	if (options) {
+		while (options->name) {
+			ret = update_option(alias, options);
+			if (ret < 0)
+				goto out_free;
+			options++;
+		}
+	}
+
+	func = dlsym(handle, TEP_PLUGIN_LOADER_NAME);
+	if (!func) {
+		tep_warning("could not find func '%s' in plugin '%s'\n%s\n",
+			    TEP_PLUGIN_LOADER_NAME, plugin, dlerror());
+		goto out_free;
+	}
+
+	list = malloc(sizeof(*list));
+	if (!list) {
+		tep_warning("could not allocate plugin memory\n");
+		goto out_free;
+	}
+
+	list->next = *plugin_list;
+	list->handle = handle;
+	list->name = plugin;
+	*plugin_list = list;
+
+	tep_info("registering plugin: %s", plugin);
+	func(tep);
+	return;
+
+ out_free:
+	free(plugin);
+}
+
+static void
+load_plugins_dir(struct tep_handle *tep, const char *suffix,
+		 const char *path,
+		 void (*load_plugin)(struct tep_handle *tep,
+				     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(tep, path, name, data);
+	}
+
+	closedir(dir);
+}
+
+/**
+ * tep_load_plugins_hook - call a user specified callback to load a plugin
+ * @tep: handler to traceevent context
+ * @suffix: filter only plugin files with given suffix
+ * @load_plugin: user specified callback, called for each plugin file
+ * @data: custom context, passed to @load_plugin
+ *
+ * Searches for traceevent plugin files and calls @load_plugin for each
+ * The order of plugins search is:
+ *  - Directories, specified in @tep->plugins_dir and priority TEP_PLUGIN_FIRST
+ *  - Directory, specified at compile time with PLUGIN_TRACEEVENT_DIR
+ *  - Directory, specified by environment variable TRACEEVENT_PLUGIN_DIR
+ *  - In user's home: ~/.local/lib/traceevent/plugins/
+ *  - Directories, specified in @tep->plugins_dir and priority TEP_PLUGIN_LAST
+ *
+ */
+void tep_load_plugins_hook(struct tep_handle *tep, const char *suffix,
+			   void (*load_plugin)(struct tep_handle *tep,
+					       const char *path,
+					       const char *name,
+					       void *data),
+			   void *data)
+{
+	struct tep_plugins_dir *dir = NULL;
+	char *home;
+	char *path;
+	char *envdir;
+	int ret;
+
+	if (tep && tep->flags & TEP_DISABLE_PLUGINS)
+		return;
+
+	if (tep)
+		dir = tep->plugins_dir;
+	while (dir) {
+		if (dir->prio == TEP_PLUGIN_FIRST)
+			load_plugins_dir(tep, suffix, dir->path,
+					 load_plugin, data);
+		dir = dir->next;
+	}
+
+	/*
+	 * If a system plugin directory was defined,
+	 * check that first.
+	 */
+#ifdef PLUGIN_DIR
+	if (!tep || !(tep->flags & TEP_DISABLE_SYS_PLUGINS))
+		load_plugins_dir(tep, 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(tep, 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) {
+		tep_warning("could not allocate plugin memory\n");
+		return;
+	}
+
+	load_plugins_dir(tep, suffix, path, load_plugin, data);
+
+	if (tep)
+		dir = tep->plugins_dir;
+	while (dir) {
+		if (dir->prio == TEP_PLUGIN_LAST)
+			load_plugins_dir(tep, suffix, dir->path,
+					 load_plugin, data);
+		dir = dir->next;
+	}
+
+	free(path);
+}
+
+struct tep_plugin_list*
+tep_load_plugins(struct tep_handle *tep)
+{
+	struct tep_plugin_list *list = NULL;
+
+	tep_load_plugins_hook(tep, ".so", load_plugin, &list);
+	return list;
+}
+
+/**
+ * tep_add_plugin_path - Add a new plugin directory.
+ * @tep: Trace event handler.
+ * @path: Path to a directory. All plugin files in that
+ *	  directory will be loaded.
+ *@prio: Load priority of the plugins in that directory.
+ *
+ * Returns -1 in case of an error, 0 otherwise.
+ */
+int tep_add_plugin_path(struct tep_handle *tep, char *path,
+			enum tep_plugin_load_priority prio)
+{
+	struct tep_plugins_dir *dir;
+
+	if (!tep || !path)
+		return -1;
+
+	dir = calloc(1, sizeof(*dir));
+	if (!dir)
+		return -1;
+
+	dir->path = strdup(path);
+	if (!dir->path) {
+		free(dir);
+		return -1;
+	}
+	dir->prio = prio;
+	dir->next = tep->plugins_dir;
+	tep->plugins_dir = dir;
+
+	return 0;
+}
+
+__hidden void free_tep_plugin_paths(struct tep_handle *tep)
+{
+	struct tep_plugins_dir *dir;
+
+	if (!tep)
+		return;
+
+	dir = tep->plugins_dir;
+	while (dir) {
+		tep->plugins_dir = tep->plugins_dir->next;
+		free(dir->path);
+		free(dir);
+		dir = tep->plugins_dir;
+	}
+}
+
+void
+tep_unload_plugins(struct tep_plugin_list *plugin_list, struct tep_handle *tep)
+{
+	tep_plugin_unload_func func;
+	struct tep_plugin_list *list;
+
+	while (plugin_list) {
+		list = plugin_list;
+		plugin_list = list->next;
+		func = dlsym(list->handle, TEP_PLUGIN_UNLOADER_NAME);
+		if (func)
+			func(tep);
+		dlclose(list->handle);
+		free(list->name);
+		free(list);
+	}
+}