Backporting plugin support for traceevent lib. Backported from Steven Rostedt's trace-cmd repo (HEAD 0f2c2fb): git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
It's now possible to use following interface to load plugins (shared objects) to enhance pevent object functionality. The plugin interface/hooks are as follows: (taken from event-parse.h comments) - 'pevent_plugin_loader' (required) The function name to initialized the plugin. int pevent_plugin_loader(struct pevent *pevent) - 'pevent_plugin_unloader' (optional) The function called just before unloading int pevent_plugin_unloader(void) - 'pevent_plugin_options' (optional) Plugin options that can be set before loading struct plugin_option pevent_plugin_options[] = { { .name = "option-name", .plugin_alias = "overide-file-name", (optional) .description = "description of option to show users", }, { .name = NULL, }, }; Array must end with .name = NULL; The plugin_alias (below) can be used to give a shorter name to access the variable. Useful if a plugin handles more than one event. NOTE options support is not backported yet. - 'pevent_plugin_alias' (optional) The name to use for finding options (uses filename if not defined) New traceevent functions are added to search and load available plugins: struct plugin_list* traceevent_load_plugins(struct pevent *pevent) - loads plusing for 'struct pevent' object and returns loaded plugins list void traceevent_unload_plugins(struct plugin_list *plugin_list); - unload plugin list Signed-off-by: Steven Rostedt <rost...@goodmis.org> Signed-off-by: Jiri Olsa <jo...@redhat.com> Cc: Corey Ashford <cjash...@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweis...@gmail.com> Cc: Ingo Molnar <mi...@elte.hu> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net> Cc: Steven Rostedt <rost...@goodmis.org> Cc: David Ahern <dsah...@gmail.com> --- tools/lib/traceevent/Makefile | 6 +- tools/lib/traceevent/event-parse.h | 5 + tools/lib/traceevent/event-plugin.c | 202 ++++++++++++++++++++++++++++++++++++ 3 files changed, 212 insertions(+), 1 deletion(-) create mode 100644 tools/lib/traceevent/event-plugin.c diff --git a/tools/lib/traceevent/Makefile b/tools/lib/traceevent/Makefile index fc15020..2ccb5bc 100644 --- a/tools/lib/traceevent/Makefile +++ b/tools/lib/traceevent/Makefile @@ -180,7 +180,11 @@ $(obj)/%.o: $(src)/%.c %.o: $(src)/%.c $(Q)$(call do_compile) -PEVENT_LIB_OBJS = event-parse.o trace-seq.o parse-filter.o parse-utils.o +PEVENT_LIB_OBJS = event-parse.o +PEVENT_LIB_OBJS += event-plugin.o +PEVENT_LIB_OBJS += trace-seq.o +PEVENT_LIB_OBJS += parse-filter.o +PEVENT_LIB_OBJS += parse-utils.o PEVENT_LIB_OBJS += kbuffer-parse.o ALL_OBJS = $(PEVENT_LIB_OBJS) diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h index 8d73d25..a288860 100644 --- a/tools/lib/traceevent/event-parse.h +++ b/tools/lib/traceevent/event-parse.h @@ -377,6 +377,11 @@ enum pevent_errno { }; #undef _PE +struct plugin_list; + +struct plugin_list *traceevent_load_plugins(struct pevent *pevent); +void traceevent_unload_plugins(struct plugin_list *plugin_list); + struct cmdline; struct cmdline_list; struct func_map; diff --git a/tools/lib/traceevent/event-plugin.c b/tools/lib/traceevent/event-plugin.c new file mode 100644 index 0000000..d272d87 --- /dev/null +++ b/tools/lib/traceevent/event-plugin.c @@ -0,0 +1,202 @@ +/* + * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srost...@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 <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" + +struct plugin_list { + struct plugin_list *next; + char *name; + void *handle; +}; + +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; + + plugin = malloc_or_die(strlen(path) + strlen(file) + 2); + + strcpy(plugin, path); + strcat(plugin, "/"); + strcat(plugin, file); + + 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_or_die(sizeof(*list)); + 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; + + /* + * If a system plugin directory was defined, + * check that first. + */ +#ifdef PLUGIN_DIR + 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; + + path = malloc_or_die(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2); + + strcpy(path, home); + strcat(path, "/"); + strcat(path, LOCAL_PLUGIN_DIR); + + 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) +{ + 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(); + dlclose(list->handle); + free(list->name); + free(list); + } +} -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/