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