1 /*
2 * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
3 *
4 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation;
8 * version 2.1 of the License (not later!)
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this program; if not, see <http://www.gnu.org/licenses>
17 *
18 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
19 */
20
21 #include <ctype.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <dlfcn.h>
25 #include <stdlib.h>
26 #include <sys/types.h>
27 #include <sys/stat.h>
28 #include <unistd.h>
29 #include <dirent.h>
30 #include "event-parse.h"
31 #include "event-utils.h"
32
33 #define LOCAL_PLUGIN_DIR ".local/lib/traceevent/plugins/"
34
35 static struct registered_plugin_options {
36 struct registered_plugin_options *next;
37 struct pevent_plugin_option *options;
38 } *registered_options;
39
40 static struct trace_plugin_options {
41 struct trace_plugin_options *next;
42 char *plugin;
43 char *option;
44 char *value;
45 } *trace_plugin_options;
46
47 struct plugin_list {
48 struct plugin_list *next;
49 char *name;
50 void *handle;
51 };
52
lower_case(char * str)53 static void lower_case(char *str)
54 {
55 if (!str)
56 return;
57 for (; *str; str++)
58 *str = tolower(*str);
59 }
60
update_option_value(struct pevent_plugin_option * op,const char * val)61 static int update_option_value(struct pevent_plugin_option *op, const char *val)
62 {
63 char *op_val;
64
65 if (!val) {
66 /* toggle, only if option is boolean */
67 if (op->value)
68 /* Warn? */
69 return 0;
70 op->set ^= 1;
71 return 0;
72 }
73
74 /*
75 * If the option has a value then it takes a string
76 * otherwise the option is a boolean.
77 */
78 if (op->value) {
79 op->value = val;
80 return 0;
81 }
82
83 /* Option is boolean, must be either "1", "0", "true" or "false" */
84
85 op_val = strdup(val);
86 if (!op_val)
87 return -1;
88 lower_case(op_val);
89
90 if (strcmp(val, "1") == 0 || strcmp(val, "true") == 0)
91 op->set = 1;
92 else if (strcmp(val, "0") == 0 || strcmp(val, "false") == 0)
93 op->set = 0;
94 free(op_val);
95
96 return 0;
97 }
98
99 /**
100 * traceevent_plugin_list_options - get list of plugin options
101 *
102 * Returns an array of char strings that list the currently registered
103 * plugin options in the format of <plugin>:<option>. This list can be
104 * used by toggling the option.
105 *
106 * Returns NULL if there's no options registered. On error it returns
107 * INVALID_PLUGIN_LIST_OPTION
108 *
109 * Must be freed with traceevent_plugin_free_options_list().
110 */
traceevent_plugin_list_options(void)111 char **traceevent_plugin_list_options(void)
112 {
113 struct registered_plugin_options *reg;
114 struct pevent_plugin_option *op;
115 char **list = NULL;
116 char *name;
117 int count = 0;
118
119 for (reg = registered_options; reg; reg = reg->next) {
120 for (op = reg->options; op->name; op++) {
121 char *alias = op->plugin_alias ? op->plugin_alias : op->file;
122 char **temp = list;
123
124 name = malloc(strlen(op->name) + strlen(alias) + 2);
125 if (!name)
126 goto err;
127
128 sprintf(name, "%s:%s", alias, op->name);
129 list = realloc(list, count + 2);
130 if (!list) {
131 list = temp;
132 free(name);
133 goto err;
134 }
135 list[count++] = name;
136 list[count] = NULL;
137 }
138 }
139 return list;
140
141 err:
142 while (--count >= 0)
143 free(list[count]);
144 free(list);
145
146 return INVALID_PLUGIN_LIST_OPTION;
147 }
148
traceevent_plugin_free_options_list(char ** list)149 void traceevent_plugin_free_options_list(char **list)
150 {
151 int i;
152
153 if (!list)
154 return;
155
156 if (list == INVALID_PLUGIN_LIST_OPTION)
157 return;
158
159 for (i = 0; list[i]; i++)
160 free(list[i]);
161
162 free(list);
163 }
164
165 static int
update_option(const char * file,struct pevent_plugin_option * option)166 update_option(const char *file, struct pevent_plugin_option *option)
167 {
168 struct trace_plugin_options *op;
169 char *plugin;
170 int ret = 0;
171
172 if (option->plugin_alias) {
173 plugin = strdup(option->plugin_alias);
174 if (!plugin)
175 return -1;
176 } else {
177 char *p;
178 plugin = strdup(file);
179 if (!plugin)
180 return -1;
181 p = strstr(plugin, ".");
182 if (p)
183 *p = '\0';
184 }
185
186 /* first look for named options */
187 for (op = trace_plugin_options; op; op = op->next) {
188 if (!op->plugin)
189 continue;
190 if (strcmp(op->plugin, plugin) != 0)
191 continue;
192 if (strcmp(op->option, option->name) != 0)
193 continue;
194
195 ret = update_option_value(option, op->value);
196 if (ret)
197 goto out;
198 break;
199 }
200
201 /* first look for unnamed options */
202 for (op = trace_plugin_options; op; op = op->next) {
203 if (op->plugin)
204 continue;
205 if (strcmp(op->option, option->name) != 0)
206 continue;
207
208 ret = update_option_value(option, op->value);
209 break;
210 }
211
212 out:
213 free(plugin);
214 return ret;
215 }
216
217 /**
218 * traceevent_plugin_add_options - Add a set of options by a plugin
219 * @name: The name of the plugin adding the options
220 * @options: The set of options being loaded
221 *
222 * Sets the options with the values that have been added by user.
223 */
traceevent_plugin_add_options(const char * name,struct pevent_plugin_option * options)224 int traceevent_plugin_add_options(const char *name,
225 struct pevent_plugin_option *options)
226 {
227 struct registered_plugin_options *reg;
228
229 reg = malloc(sizeof(*reg));
230 if (!reg)
231 return -1;
232 reg->next = registered_options;
233 reg->options = options;
234 registered_options = reg;
235
236 while (options->name) {
237 update_option(name, options);
238 options++;
239 }
240 return 0;
241 }
242
243 /**
244 * traceevent_plugin_remove_options - remove plugin options that were registered
245 * @options: Options to removed that were registered with traceevent_plugin_add_options
246 */
traceevent_plugin_remove_options(struct pevent_plugin_option * options)247 void traceevent_plugin_remove_options(struct pevent_plugin_option *options)
248 {
249 struct registered_plugin_options **last;
250 struct registered_plugin_options *reg;
251
252 for (last = ®istered_options; *last; last = &(*last)->next) {
253 if ((*last)->options == options) {
254 reg = *last;
255 *last = reg->next;
256 free(reg);
257 return;
258 }
259 }
260 }
261
262 /**
263 * traceevent_print_plugins - print out the list of plugins loaded
264 * @s: the trace_seq descripter to write to
265 * @prefix: The prefix string to add before listing the option name
266 * @suffix: The suffix string ot append after the option name
267 * @list: The list of plugins (usually returned by traceevent_load_plugins()
268 *
269 * Writes to the trace_seq @s the list of plugins (files) that is
270 * returned by traceevent_load_plugins(). Use @prefix and @suffix for formating:
271 * @prefix = " ", @suffix = "\n".
272 */
traceevent_print_plugins(struct trace_seq * s,const char * prefix,const char * suffix,const struct plugin_list * list)273 void traceevent_print_plugins(struct trace_seq *s,
274 const char *prefix, const char *suffix,
275 const struct plugin_list *list)
276 {
277 while (list) {
278 trace_seq_printf(s, "%s%s%s", prefix, list->name, suffix);
279 list = list->next;
280 }
281 }
282
283 static void
load_plugin(struct pevent * pevent,const char * path,const char * file,void * data)284 load_plugin(struct pevent *pevent, const char *path,
285 const char *file, void *data)
286 {
287 struct plugin_list **plugin_list = data;
288 pevent_plugin_load_func func;
289 struct plugin_list *list;
290 const char *alias;
291 char *plugin;
292 void *handle;
293
294 plugin = malloc(strlen(path) + strlen(file) + 2);
295 if (!plugin) {
296 warning("could not allocate plugin memory\n");
297 return;
298 }
299
300 strcpy(plugin, path);
301 strcat(plugin, "/");
302 strcat(plugin, file);
303
304 handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
305 if (!handle) {
306 warning("could not load plugin '%s'\n%s\n",
307 plugin, dlerror());
308 goto out_free;
309 }
310
311 alias = dlsym(handle, PEVENT_PLUGIN_ALIAS_NAME);
312 if (!alias)
313 alias = file;
314
315 func = dlsym(handle, PEVENT_PLUGIN_LOADER_NAME);
316 if (!func) {
317 warning("could not find func '%s' in plugin '%s'\n%s\n",
318 PEVENT_PLUGIN_LOADER_NAME, plugin, dlerror());
319 goto out_free;
320 }
321
322 list = malloc(sizeof(*list));
323 if (!list) {
324 warning("could not allocate plugin memory\n");
325 goto out_free;
326 }
327
328 list->next = *plugin_list;
329 list->handle = handle;
330 list->name = plugin;
331 *plugin_list = list;
332
333 pr_stat("registering plugin: %s", plugin);
334 func(pevent);
335 return;
336
337 out_free:
338 free(plugin);
339 }
340
341 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)342 load_plugins_dir(struct pevent *pevent, const char *suffix,
343 const char *path,
344 void (*load_plugin)(struct pevent *pevent,
345 const char *path,
346 const char *name,
347 void *data),
348 void *data)
349 {
350 struct dirent *dent;
351 struct stat st;
352 DIR *dir;
353 int ret;
354
355 ret = stat(path, &st);
356 if (ret < 0)
357 return;
358
359 if (!S_ISDIR(st.st_mode))
360 return;
361
362 dir = opendir(path);
363 if (!dir)
364 return;
365
366 while ((dent = readdir(dir))) {
367 const char *name = dent->d_name;
368
369 if (strcmp(name, ".") == 0 ||
370 strcmp(name, "..") == 0)
371 continue;
372
373 /* Only load plugins that end in suffix */
374 if (strcmp(name + (strlen(name) - strlen(suffix)), suffix) != 0)
375 continue;
376
377 load_plugin(pevent, path, name, data);
378 }
379
380 closedir(dir);
381 }
382
383 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)384 load_plugins(struct pevent *pevent, const char *suffix,
385 void (*load_plugin)(struct pevent *pevent,
386 const char *path,
387 const char *name,
388 void *data),
389 void *data)
390 {
391 char *home;
392 char *path;
393 char *envdir;
394
395 if (pevent->flags & PEVENT_DISABLE_PLUGINS)
396 return;
397
398 /*
399 * If a system plugin directory was defined,
400 * check that first.
401 */
402 #ifdef PLUGIN_DIR
403 if (!(pevent->flags & PEVENT_DISABLE_SYS_PLUGINS))
404 load_plugins_dir(pevent, suffix, PLUGIN_DIR,
405 load_plugin, data);
406 #endif
407
408 /*
409 * Next let the environment-set plugin directory
410 * override the system defaults.
411 */
412 envdir = getenv("TRACEEVENT_PLUGIN_DIR");
413 if (envdir)
414 load_plugins_dir(pevent, suffix, envdir, load_plugin, data);
415
416 /*
417 * Now let the home directory override the environment
418 * or system defaults.
419 */
420 home = getenv("HOME");
421 if (!home)
422 return;
423
424 path = malloc(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2);
425 if (!path) {
426 warning("could not allocate plugin memory\n");
427 return;
428 }
429
430 strcpy(path, home);
431 strcat(path, "/");
432 strcat(path, LOCAL_PLUGIN_DIR);
433
434 load_plugins_dir(pevent, suffix, path, load_plugin, data);
435
436 free(path);
437 }
438
439 struct plugin_list*
traceevent_load_plugins(struct pevent * pevent)440 traceevent_load_plugins(struct pevent *pevent)
441 {
442 struct plugin_list *list = NULL;
443
444 load_plugins(pevent, ".so", load_plugin, &list);
445 return list;
446 }
447
448 void
traceevent_unload_plugins(struct plugin_list * plugin_list,struct pevent * pevent)449 traceevent_unload_plugins(struct plugin_list *plugin_list, struct pevent *pevent)
450 {
451 pevent_plugin_unload_func func;
452 struct plugin_list *list;
453
454 while (plugin_list) {
455 list = plugin_list;
456 plugin_list = list->next;
457 func = dlsym(list->handle, PEVENT_PLUGIN_UNLOADER_NAME);
458 if (func)
459 func(pevent);
460 dlclose(list->handle);
461 free(list->name);
462 free(list);
463 }
464 }
465