2 files changed, 209 insertions, 3 deletions

diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index a68ec3d8289f..56e0e6c12411 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -107,8 +107,8 @@ typedef int (*pevent_event_handler_func)(struct trace_seq *s,
 typedef int (*pevent_plugin_load_func)(struct pevent *pevent);
 typedef int (*pevent_plugin_unload_func)(struct pevent *pevent);
 
-struct plugin_option {
-        struct plugin_option            *next;
+struct pevent_plugin_option {
+        struct pevent_plugin_option     *next;
         void                            *handle;
         char                            *file;
         char                            *name;
@@ -135,7 +135,7 @@ struct plugin_option {
  * PEVENT_PLUGIN_OPTIONS:  (optional)
  *   Plugin options that can be set before loading
  *
- *   struct plugin_option PEVENT_PLUGIN_OPTIONS[] = {
+ *   struct pevent_plugin_option PEVENT_PLUGIN_OPTIONS[] = {
  *      {
  *              .name = "option-name",
  *              .plugin_alias = "overide-file-name", (optional)
@@ -412,9 +412,19 @@ enum pevent_errno {
 
 struct plugin_list;
 
+#define INVALID_PLUGIN_LIST_OPTION      ((char **)((unsigned long)-1))
+
 struct plugin_list *traceevent_load_plugins(struct pevent *pevent);
 void traceevent_unload_plugins(struct plugin_list *plugin_list,
                                struct pevent *pevent);
+char **traceevent_plugin_list_options(void);
+void traceevent_plugin_free_options_list(char **list);
+int traceevent_plugin_add_options(const char *name,
+                                  struct pevent_plugin_option *options);
+void traceevent_plugin_remove_options(struct pevent_plugin_option *options);
+void traceevent_print_plugins(struct trace_seq *s,
+                              const char *prefix, const char *suffix,
+                              const struct plugin_list *list);
 
 struct cmdline;
 struct cmdline_list;
diff --git a/tools/lib/traceevent/event-plugin.c b/tools/lib/traceevent/event-plugin.c
index 317466bd1a37..136162c03af1 100644
--- a/tools/lib/traceevent/event-plugin.c
+++ b/tools/lib/traceevent/event-plugin.c
@@ -18,6 +18,7 @@
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
 
+#include <stdio.h>
 #include <string.h>
 #include <dlfcn.h>
 #include <stdlib.h>
@@ -30,12 +31,207 @@
 
 #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;
 };
 
+/**
+ * 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;
+
+                        name = malloc(strlen(op->name) + strlen(alias) + 2);
+                        if (!name)
+                                goto err;
+
+                        sprintf(name, "%s:%s", alias, op->name);
+                        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;
+
+        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;
+
+                option->value = op->value;
+                option->set ^= 1;
+                goto out;
+        }
+
+        /* 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;
+
+                option->value = op->value;
+                option->set ^= 1;
+                break;
+        }
+
+ out:
+        free(plugin);
+        return 0;
+}
+
+/**
+ * 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)