linuxdebug/tools/lib/traceevent/event-plugin.c

712 lines
15 KiB
C

// 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) {
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, 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) {
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) {
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(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) {
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);
}
}