1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * trace_events_trigger - trace event triggers
4 *
5 * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
6 */
7
8 #include <linux/security.h>
9 #include <linux/module.h>
10 #include <linux/ctype.h>
11 #include <linux/mutex.h>
12 #include <linux/slab.h>
13 #include <linux/rculist.h>
14
15 #include "trace.h"
16
17 static LIST_HEAD(trigger_commands);
18 static DEFINE_MUTEX(trigger_cmd_mutex);
19
20 void trigger_data_free(struct event_trigger_data *data)
21 {
22 if (data->cmd_ops->set_filter)
23 data->cmd_ops->set_filter(NULL, data, NULL);
24
25 /* make sure current triggers exit before free */
26 tracepoint_synchronize_unregister();
27
28 kfree(data);
29 }
30
31 /**
32 * event_triggers_call - Call triggers associated with a trace event
33 * @file: The trace_event_file associated with the event
34 * @buffer: The ring buffer that the event is being written to
35 * @rec: The trace entry for the event, NULL for unconditional invocation
36 * @event: The event meta data in the ring buffer
37 *
38 * For each trigger associated with an event, invoke the trigger
39 * function registered with the associated trigger command. If rec is
40 * non-NULL, it means that the trigger requires further processing and
41 * shouldn't be unconditionally invoked. If rec is non-NULL and the
42 * trigger has a filter associated with it, rec will checked against
43 * the filter and if the record matches the trigger will be invoked.
44 * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
45 * in any case until the current event is written, the trigger
46 * function isn't invoked but the bit associated with the deferred
47 * trigger is set in the return value.
48 *
49 * Returns an enum event_trigger_type value containing a set bit for
50 * any trigger that should be deferred, ETT_NONE if nothing to defer.
51 *
52 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
53 *
54 * Return: an enum event_trigger_type value containing a set bit for
55 * any trigger that should be deferred, ETT_NONE if nothing to defer.
56 */
57 enum event_trigger_type
58 event_triggers_call(struct trace_event_file *file,
59 struct trace_buffer *buffer, void *rec,
60 struct ring_buffer_event *event)
61 {
62 struct event_trigger_data *data;
63 enum event_trigger_type tt = ETT_NONE;
64 struct event_filter *filter;
65
66 if (list_empty(&file->triggers))
67 return tt;
68
69 list_for_each_entry_rcu(data, &file->triggers, list) {
70 if (data->paused)
71 continue;
72 if (!rec) {
73 data->ops->trigger(data, buffer, rec, event);
74 continue;
75 }
76 filter = rcu_dereference_sched(data->filter);
77 if (filter && !filter_match_preds(filter, rec))
78 continue;
79 if (event_command_post_trigger(data->cmd_ops)) {
80 tt |= data->cmd_ops->trigger_type;
81 continue;
82 }
83 data->ops->trigger(data, buffer, rec, event);
84 }
85 return tt;
86 }
87 EXPORT_SYMBOL_GPL(event_triggers_call);
88
89 bool __trace_trigger_soft_disabled(struct trace_event_file *file)
90 {
91 unsigned long eflags = file->flags;
92
93 if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
94 event_triggers_call(file, NULL, NULL, NULL);
95 if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
96 return true;
97 if (eflags & EVENT_FILE_FL_PID_FILTER)
98 return trace_event_ignore_this_pid(file);
99 return false;
100 }
101 EXPORT_SYMBOL_GPL(__trace_trigger_soft_disabled);
102
103 /**
104 * event_triggers_post_call - Call 'post_triggers' for a trace event
105 * @file: The trace_event_file associated with the event
106 * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
107 *
108 * For each trigger associated with an event, invoke the trigger
109 * function registered with the associated trigger command, if the
110 * corresponding bit is set in the tt enum passed into this function.
111 * See @event_triggers_call for details on how those bits are set.
112 *
113 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
114 */
115 void
116 event_triggers_post_call(struct trace_event_file *file,
117 enum event_trigger_type tt)
118 {
119 struct event_trigger_data *data;
120
121 list_for_each_entry_rcu(data, &file->triggers, list) {
122 if (data->paused)
123 continue;
124 if (data->cmd_ops->trigger_type & tt)
125 data->ops->trigger(data, NULL, NULL, NULL);
126 }
127 }
128 EXPORT_SYMBOL_GPL(event_triggers_post_call);
129
130 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
131
132 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
133 {
134 struct trace_event_file *event_file = event_file_data(m->private);
135
136 if (t == SHOW_AVAILABLE_TRIGGERS) {
137 (*pos)++;
138 return NULL;
139 }
140 return seq_list_next(t, &event_file->triggers, pos);
141 }
142
143 static bool check_user_trigger(struct trace_event_file *file)
144 {
145 struct event_trigger_data *data;
146
147 list_for_each_entry_rcu(data, &file->triggers, list,
148 lockdep_is_held(&event_mutex)) {
149 if (data->flags & EVENT_TRIGGER_FL_PROBE)
150 continue;
151 return true;
152 }
153 return false;
154 }
155
156 static void *trigger_start(struct seq_file *m, loff_t *pos)
157 {
158 struct trace_event_file *event_file;
159
160 /* ->stop() is called even if ->start() fails */
161 mutex_lock(&event_mutex);
162 event_file = event_file_file(m->private);
163 if (unlikely(!event_file))
164 return ERR_PTR(-ENODEV);
165
166 if (list_empty(&event_file->triggers) || !check_user_trigger(event_file))
167 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
168
169 return seq_list_start(&event_file->triggers, *pos);
170 }
171
172 static void trigger_stop(struct seq_file *m, void *t)
173 {
174 mutex_unlock(&event_mutex);
175 }
176
177 static int trigger_show(struct seq_file *m, void *v)
178 {
179 struct event_trigger_data *data;
180 struct event_command *p;
181
182 if (v == SHOW_AVAILABLE_TRIGGERS) {
183 seq_puts(m, "# Available triggers:\n");
184 seq_putc(m, '#');
185 mutex_lock(&trigger_cmd_mutex);
186 list_for_each_entry_reverse(p, &trigger_commands, list)
187 seq_printf(m, " %s", p->name);
188 seq_putc(m, '\n');
189 mutex_unlock(&trigger_cmd_mutex);
190 return 0;
191 }
192
193 data = list_entry(v, struct event_trigger_data, list);
194 data->ops->print(m, data);
195
196 return 0;
197 }
198
199 static const struct seq_operations event_triggers_seq_ops = {
200 .start = trigger_start,
201 .next = trigger_next,
202 .stop = trigger_stop,
203 .show = trigger_show,
204 };
205
206 static int event_trigger_regex_open(struct inode *inode, struct file *file)
207 {
208 int ret;
209
210 ret = security_locked_down(LOCKDOWN_TRACEFS);
211 if (ret)
212 return ret;
213
214 mutex_lock(&event_mutex);
215
216 if (unlikely(!event_file_file(file))) {
217 mutex_unlock(&event_mutex);
218 return -ENODEV;
219 }
220
221 if ((file->f_mode & FMODE_WRITE) &&
222 (file->f_flags & O_TRUNC)) {
223 struct trace_event_file *event_file;
224 struct event_command *p;
225
226 event_file = event_file_data(file);
227
228 list_for_each_entry(p, &trigger_commands, list) {
229 if (p->unreg_all)
230 p->unreg_all(event_file);
231 }
232 }
233
234 if (file->f_mode & FMODE_READ) {
235 ret = seq_open(file, &event_triggers_seq_ops);
236 if (!ret) {
237 struct seq_file *m = file->private_data;
238 m->private = file;
239 }
240 }
241
242 mutex_unlock(&event_mutex);
243
244 return ret;
245 }
246
247 int trigger_process_regex(struct trace_event_file *file, char *buff)
248 {
249 char *command, *next;
250 struct event_command *p;
251 int ret = -EINVAL;
252
253 next = buff = skip_spaces(buff);
254 command = strsep(&next, ": \t");
255 if (next) {
256 next = skip_spaces(next);
257 if (!*next)
258 next = NULL;
259 }
260 command = (command[0] != '!') ? command : command + 1;
261
262 mutex_lock(&trigger_cmd_mutex);
263 list_for_each_entry(p, &trigger_commands, list) {
264 if (strcmp(p->name, command) == 0) {
265 ret = p->parse(p, file, buff, command, next);
266 goto out_unlock;
267 }
268 }
269 out_unlock:
270 mutex_unlock(&trigger_cmd_mutex);
271
272 return ret;
273 }
274
275 static ssize_t event_trigger_regex_write(struct file *file,
276 const char __user *ubuf,
277 size_t cnt, loff_t *ppos)
278 {
279 struct trace_event_file *event_file;
280 ssize_t ret;
281 char *buf;
282
283 if (!cnt)
284 return 0;
285
286 if (cnt >= PAGE_SIZE)
287 return -EINVAL;
288
289 buf = memdup_user_nul(ubuf, cnt);
290 if (IS_ERR(buf))
291 return PTR_ERR(buf);
292
293 strim(buf);
294
295 mutex_lock(&event_mutex);
296 event_file = event_file_file(file);
297 if (unlikely(!event_file)) {
298 mutex_unlock(&event_mutex);
299 kfree(buf);
300 return -ENODEV;
301 }
302 ret = trigger_process_regex(event_file, buf);
303 mutex_unlock(&event_mutex);
304
305 kfree(buf);
306 if (ret < 0)
307 goto out;
308
309 *ppos += cnt;
310 ret = cnt;
311 out:
312 return ret;
313 }
314
315 static int event_trigger_regex_release(struct inode *inode, struct file *file)
316 {
317 mutex_lock(&event_mutex);
318
319 if (file->f_mode & FMODE_READ)
320 seq_release(inode, file);
321
322 mutex_unlock(&event_mutex);
323
324 return 0;
325 }
326
327 static ssize_t
328 event_trigger_write(struct file *filp, const char __user *ubuf,
329 size_t cnt, loff_t *ppos)
330 {
331 return event_trigger_regex_write(filp, ubuf, cnt, ppos);
332 }
333
334 static int
335 event_trigger_open(struct inode *inode, struct file *filp)
336 {
337 /* Checks for tracefs lockdown */
338 return event_trigger_regex_open(inode, filp);
339 }
340
341 static int
342 event_trigger_release(struct inode *inode, struct file *file)
343 {
344 return event_trigger_regex_release(inode, file);
345 }
346
347 const struct file_operations event_trigger_fops = {
348 .open = event_trigger_open,
349 .read = seq_read,
350 .write = event_trigger_write,
351 .llseek = tracing_lseek,
352 .release = event_trigger_release,
353 };
354
355 /*
356 * Currently we only register event commands from __init, so mark this
357 * __init too.
358 */
359 __init int register_event_command(struct event_command *cmd)
360 {
361 struct event_command *p;
362 int ret = 0;
363
364 mutex_lock(&trigger_cmd_mutex);
365 list_for_each_entry(p, &trigger_commands, list) {
366 if (strcmp(cmd->name, p->name) == 0) {
367 ret = -EBUSY;
368 goto out_unlock;
369 }
370 }
371 list_add(&cmd->list, &trigger_commands);
372 out_unlock:
373 mutex_unlock(&trigger_cmd_mutex);
374
375 return ret;
376 }
377
378 /*
379 * Currently we only unregister event commands from __init, so mark
380 * this __init too.
381 */
382 __init int unregister_event_command(struct event_command *cmd)
383 {
384 struct event_command *p, *n;
385 int ret = -ENODEV;
386
387 mutex_lock(&trigger_cmd_mutex);
388 list_for_each_entry_safe(p, n, &trigger_commands, list) {
389 if (strcmp(cmd->name, p->name) == 0) {
390 ret = 0;
391 list_del_init(&p->list);
392 goto out_unlock;
393 }
394 }
395 out_unlock:
396 mutex_unlock(&trigger_cmd_mutex);
397
398 return ret;
399 }
400
401 /**
402 * event_trigger_print - Generic event_trigger_ops @print implementation
403 * @name: The name of the event trigger
404 * @m: The seq_file being printed to
405 * @data: Trigger-specific data
406 * @filter_str: filter_str to print, if present
407 *
408 * Common implementation for event triggers to print themselves.
409 *
410 * Usually wrapped by a function that simply sets the @name of the
411 * trigger command and then invokes this.
412 *
413 * Return: 0 on success, errno otherwise
414 */
415 static int
416 event_trigger_print(const char *name, struct seq_file *m,
417 void *data, char *filter_str)
418 {
419 long count = (long)data;
420
421 seq_puts(m, name);
422
423 if (count == -1)
424 seq_puts(m, ":unlimited");
425 else
426 seq_printf(m, ":count=%ld", count);
427
428 if (filter_str)
429 seq_printf(m, " if %s\n", filter_str);
430 else
431 seq_putc(m, '\n');
432
433 return 0;
434 }
435
436 /**
437 * event_trigger_init - Generic event_trigger_ops @init implementation
438 * @data: Trigger-specific data
439 *
440 * Common implementation of event trigger initialization.
441 *
442 * Usually used directly as the @init method in event trigger
443 * implementations.
444 *
445 * Return: 0 on success, errno otherwise
446 */
447 int event_trigger_init(struct event_trigger_data *data)
448 {
449 data->ref++;
450 return 0;
451 }
452
453 /**
454 * event_trigger_free - Generic event_trigger_ops @free implementation
455 * @data: Trigger-specific data
456 *
457 * Common implementation of event trigger de-initialization.
458 *
459 * Usually used directly as the @free method in event trigger
460 * implementations.
461 */
462 static void
463 event_trigger_free(struct event_trigger_data *data)
464 {
465 if (WARN_ON_ONCE(data->ref <= 0))
466 return;
467
468 data->ref--;
469 if (!data->ref)
470 trigger_data_free(data);
471 }
472
473 int trace_event_trigger_enable_disable(struct trace_event_file *file,
474 int trigger_enable)
475 {
476 int ret = 0;
477
478 if (trigger_enable) {
479 if (atomic_inc_return(&file->tm_ref) > 1)
480 return ret;
481 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
482 ret = trace_event_enable_disable(file, 1, 1);
483 } else {
484 if (atomic_dec_return(&file->tm_ref) > 0)
485 return ret;
486 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
487 ret = trace_event_enable_disable(file, 0, 1);
488 }
489
490 return ret;
491 }
492
493 /**
494 * clear_event_triggers - Clear all triggers associated with a trace array
495 * @tr: The trace array to clear
496 *
497 * For each trigger, the triggering event has its tm_ref decremented
498 * via trace_event_trigger_enable_disable(), and any associated event
499 * (in the case of enable/disable_event triggers) will have its sm_ref
500 * decremented via free()->trace_event_enable_disable(). That
501 * combination effectively reverses the soft-mode/trigger state added
502 * by trigger registration.
503 *
504 * Must be called with event_mutex held.
505 */
506 void
507 clear_event_triggers(struct trace_array *tr)
508 {
509 struct trace_event_file *file;
510
511 list_for_each_entry(file, &tr->events, list) {
512 struct event_trigger_data *data, *n;
513 list_for_each_entry_safe(data, n, &file->triggers, list) {
514 trace_event_trigger_enable_disable(file, 0);
515 list_del_rcu(&data->list);
516 if (data->ops->free)
517 data->ops->free(data);
518 }
519 }
520 }
521
522 /**
523 * update_cond_flag - Set or reset the TRIGGER_COND bit
524 * @file: The trace_event_file associated with the event
525 *
526 * If an event has triggers and any of those triggers has a filter or
527 * a post_trigger, trigger invocation needs to be deferred until after
528 * the current event has logged its data, and the event should have
529 * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
530 * cleared.
531 */
532 void update_cond_flag(struct trace_event_file *file)
533 {
534 struct event_trigger_data *data;
535 bool set_cond = false;
536
537 lockdep_assert_held(&event_mutex);
538
539 list_for_each_entry(data, &file->triggers, list) {
540 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
541 event_command_needs_rec(data->cmd_ops)) {
542 set_cond = true;
543 break;
544 }
545 }
546
547 if (set_cond)
548 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
549 else
550 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
551 }
552
553 /**
554 * register_trigger - Generic event_command @reg implementation
555 * @glob: The raw string used to register the trigger
556 * @data: Trigger-specific data to associate with the trigger
557 * @file: The trace_event_file associated with the event
558 *
559 * Common implementation for event trigger registration.
560 *
561 * Usually used directly as the @reg method in event command
562 * implementations.
563 *
564 * Return: 0 on success, errno otherwise
565 */
566 static int register_trigger(char *glob,
567 struct event_trigger_data *data,
568 struct trace_event_file *file)
569 {
570 struct event_trigger_data *test;
571 int ret = 0;
572
573 lockdep_assert_held(&event_mutex);
574
575 list_for_each_entry(test, &file->triggers, list) {
576 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
577 ret = -EEXIST;
578 goto out;
579 }
580 }
581
582 if (data->ops->init) {
583 ret = data->ops->init(data);
584 if (ret < 0)
585 goto out;
586 }
587
588 list_add_rcu(&data->list, &file->triggers);
589
590 update_cond_flag(file);
591 ret = trace_event_trigger_enable_disable(file, 1);
592 if (ret < 0) {
593 list_del_rcu(&data->list);
594 update_cond_flag(file);
595 }
596 out:
597 return ret;
598 }
599
600 /*
601 * True if the trigger was found and unregistered, else false.
602 */
603 static bool try_unregister_trigger(char *glob,
604 struct event_trigger_data *test,
605 struct trace_event_file *file)
606 {
607 struct event_trigger_data *data = NULL, *iter;
608
609 lockdep_assert_held(&event_mutex);
610
611 list_for_each_entry(iter, &file->triggers, list) {
612 if (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
613 data = iter;
614 list_del_rcu(&data->list);
615 trace_event_trigger_enable_disable(file, 0);
616 update_cond_flag(file);
617 break;
618 }
619 }
620
621 if (data) {
622 if (data->ops->free)
623 data->ops->free(data);
624
625 return true;
626 }
627
628 return false;
629 }
630
631 /**
632 * unregister_trigger - Generic event_command @unreg implementation
633 * @glob: The raw string used to register the trigger
634 * @test: Trigger-specific data used to find the trigger to remove
635 * @file: The trace_event_file associated with the event
636 *
637 * Common implementation for event trigger unregistration.
638 *
639 * Usually used directly as the @unreg method in event command
640 * implementations.
641 */
642 static void unregister_trigger(char *glob,
643 struct event_trigger_data *test,
644 struct trace_event_file *file)
645 {
646 try_unregister_trigger(glob, test, file);
647 }
648
649 /*
650 * Event trigger parsing helper functions.
651 *
652 * These functions help make it easier to write an event trigger
653 * parsing function i.e. the struct event_command.parse() callback
654 * function responsible for parsing and registering a trigger command
655 * written to the 'trigger' file.
656 *
657 * A trigger command (or just 'trigger' for short) takes the form:
658 * [trigger] [if filter]
659 *
660 * The struct event_command.parse() callback (and other struct
661 * event_command functions) refer to several components of a trigger
662 * command. Those same components are referenced by the event trigger
663 * parsing helper functions defined below. These components are:
664 *
665 * cmd - the trigger command name
666 * glob - the trigger command name optionally prefaced with '!'
667 * param_and_filter - text following cmd and ':'
668 * param - text following cmd and ':' and stripped of filter
669 * filter - the optional filter text following (and including) 'if'
670 *
671 * To illustrate the use of these componenents, here are some concrete
672 * examples. For the following triggers:
673 *
674 * echo 'traceon:5 if pid == 0' > trigger
675 * - 'traceon' is both cmd and glob
676 * - '5 if pid == 0' is the param_and_filter
677 * - '5' is the param
678 * - 'if pid == 0' is the filter
679 *
680 * echo 'enable_event:sys:event:n' > trigger
681 * - 'enable_event' is both cmd and glob
682 * - 'sys:event:n' is the param_and_filter
683 * - 'sys:event:n' is the param
684 * - there is no filter
685 *
686 * echo 'hist:keys=pid if prio > 50' > trigger
687 * - 'hist' is both cmd and glob
688 * - 'keys=pid if prio > 50' is the param_and_filter
689 * - 'keys=pid' is the param
690 * - 'if prio > 50' is the filter
691 *
692 * echo '!enable_event:sys:event:n' > trigger
693 * - 'enable_event' the cmd
694 * - '!enable_event' is the glob
695 * - 'sys:event:n' is the param_and_filter
696 * - 'sys:event:n' is the param
697 * - there is no filter
698 *
699 * echo 'traceoff' > trigger
700 * - 'traceoff' is both cmd and glob
701 * - there is no param_and_filter
702 * - there is no param
703 * - there is no filter
704 *
705 * There are a few different categories of event trigger covered by
706 * these helpers:
707 *
708 * - triggers that don't require a parameter e.g. traceon
709 * - triggers that do require a parameter e.g. enable_event and hist
710 * - triggers that though they may not require a param may support an
711 * optional 'n' param (n = number of times the trigger should fire)
712 * e.g.: traceon:5 or enable_event:sys:event:n
713 * - triggers that do not support an 'n' param e.g. hist
714 *
715 * These functions can be used or ignored as necessary - it all
716 * depends on the complexity of the trigger, and the granularity of
717 * the functions supported reflects the fact that some implementations
718 * may need to customize certain aspects of their implementations and
719 * won't need certain functions. For instance, the hist trigger
720 * implementation doesn't use event_trigger_separate_filter() because
721 * it has special requirements for handling the filter.
722 */
723
724 /**
725 * event_trigger_check_remove - check whether an event trigger specifies remove
726 * @glob: The trigger command string, with optional remove(!) operator
727 *
728 * The event trigger callback implementations pass in 'glob' as a
729 * parameter. This is the command name either with or without a
730 * remove(!) operator. This function simply parses the glob and
731 * determines whether the command corresponds to a trigger removal or
732 * a trigger addition.
733 *
734 * Return: true if this is a remove command, false otherwise
735 */
736 bool event_trigger_check_remove(const char *glob)
737 {
738 return (glob && glob[0] == '!') ? true : false;
739 }
740
741 /**
742 * event_trigger_empty_param - check whether the param is empty
743 * @param: The trigger param string
744 *
745 * The event trigger callback implementations pass in 'param' as a
746 * parameter. This corresponds to the string following the command
747 * name minus the command name. This function can be called by a
748 * callback implementation for any command that requires a param; a
749 * callback that doesn't require a param can ignore it.
750 *
751 * Return: true if this is an empty param, false otherwise
752 */
753 bool event_trigger_empty_param(const char *param)
754 {
755 return !param;
756 }
757
758 /**
759 * event_trigger_separate_filter - separate an event trigger from a filter
760 * @param_and_filter: String containing trigger and possibly filter
761 * @param: outparam, will be filled with a pointer to the trigger
762 * @filter: outparam, will be filled with a pointer to the filter
763 * @param_required: Specifies whether or not the param string is required
764 *
765 * Given a param string of the form '[trigger] [if filter]', this
766 * function separates the filter from the trigger and returns the
767 * trigger in @param and the filter in @filter. Either the @param
768 * or the @filter may be set to NULL by this function - if not set to
769 * NULL, they will contain strings corresponding to the trigger and
770 * filter.
771 *
772 * There are two cases that need to be handled with respect to the
773 * passed-in param: either the param is required, or it is not
774 * required. If @param_required is set, and there's no param, it will
775 * return -EINVAL. If @param_required is not set and there's a param
776 * that starts with a number, that corresponds to the case of a
777 * trigger with :n (n = number of times the trigger should fire) and
778 * the parsing continues normally; otherwise the function just returns
779 * and assumes param just contains a filter and there's nothing else
780 * to do.
781 *
782 * Return: 0 on success, errno otherwise
783 */
784 int event_trigger_separate_filter(char *param_and_filter, char **param,
785 char **filter, bool param_required)
786 {
787 int ret = 0;
788
789 *param = *filter = NULL;
790
791 if (!param_and_filter) {
792 if (param_required)
793 ret = -EINVAL;
794 goto out;
795 }
796
797 /*
798 * Here we check for an optional param. The only legal
799 * optional param is :n, and if that's the case, continue
800 * below. Otherwise we assume what's left is a filter and
801 * return it as the filter string for the caller to deal with.
802 */
803 if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
804 *filter = param_and_filter;
805 goto out;
806 }
807
808 /*
809 * Separate the param from the filter (param [if filter]).
810 * Here we have either an optional :n param or a required
811 * param and an optional filter.
812 */
813 *param = strsep(¶m_and_filter, " \t");
814
815 /*
816 * Here we have a filter, though it may be empty.
817 */
818 if (param_and_filter) {
819 *filter = skip_spaces(param_and_filter);
820 if (!**filter)
821 *filter = NULL;
822 }
823 out:
824 return ret;
825 }
826
827 /**
828 * event_trigger_alloc - allocate and init event_trigger_data for a trigger
829 * @cmd_ops: The event_command operations for the trigger
830 * @cmd: The cmd string
831 * @param: The param string
832 * @private_data: User data to associate with the event trigger
833 *
834 * Allocate an event_trigger_data instance and initialize it. The
835 * @cmd_ops are used along with the @cmd and @param to get the
836 * trigger_ops to assign to the event_trigger_data. @private_data can
837 * also be passed in and associated with the event_trigger_data.
838 *
839 * Use event_trigger_free() to free an event_trigger_data object.
840 *
841 * Return: The trigger_data object success, NULL otherwise
842 */
843 struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
844 char *cmd,
845 char *param,
846 void *private_data)
847 {
848 struct event_trigger_data *trigger_data;
849 struct event_trigger_ops *trigger_ops;
850
851 trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
852
853 trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
854 if (!trigger_data)
855 return NULL;
856
857 trigger_data->count = -1;
858 trigger_data->ops = trigger_ops;
859 trigger_data->cmd_ops = cmd_ops;
860 trigger_data->private_data = private_data;
861
862 INIT_LIST_HEAD(&trigger_data->list);
863 INIT_LIST_HEAD(&trigger_data->named_list);
864 RCU_INIT_POINTER(trigger_data->filter, NULL);
865
866 return trigger_data;
867 }
868
869 /**
870 * event_trigger_parse_num - parse and return the number param for a trigger
871 * @param: The param string
872 * @trigger_data: The trigger_data for the trigger
873 *
874 * Parse the :n (n = number of times the trigger should fire) param
875 * and set the count variable in the trigger_data to the parsed count.
876 *
877 * Return: 0 on success, errno otherwise
878 */
879 int event_trigger_parse_num(char *param,
880 struct event_trigger_data *trigger_data)
881 {
882 char *number;
883 int ret = 0;
884
885 if (param) {
886 number = strsep(¶m, ":");
887
888 if (!strlen(number))
889 return -EINVAL;
890
891 /*
892 * We use the callback data field (which is a pointer)
893 * as our counter.
894 */
895 ret = kstrtoul(number, 0, &trigger_data->count);
896 }
897
898 return ret;
899 }
900
901 /**
902 * event_trigger_set_filter - set an event trigger's filter
903 * @cmd_ops: The event_command operations for the trigger
904 * @file: The event file for the trigger's event
905 * @param: The string containing the filter
906 * @trigger_data: The trigger_data for the trigger
907 *
908 * Set the filter for the trigger. If the filter is NULL, just return
909 * without error.
910 *
911 * Return: 0 on success, errno otherwise
912 */
913 int event_trigger_set_filter(struct event_command *cmd_ops,
914 struct trace_event_file *file,
915 char *param,
916 struct event_trigger_data *trigger_data)
917 {
918 if (param && cmd_ops->set_filter)
919 return cmd_ops->set_filter(param, trigger_data, file);
920
921 return 0;
922 }
923
924 /**
925 * event_trigger_reset_filter - reset an event trigger's filter
926 * @cmd_ops: The event_command operations for the trigger
927 * @trigger_data: The trigger_data for the trigger
928 *
929 * Reset the filter for the trigger to no filter.
930 */
931 void event_trigger_reset_filter(struct event_command *cmd_ops,
932 struct event_trigger_data *trigger_data)
933 {
934 if (cmd_ops->set_filter)
935 cmd_ops->set_filter(NULL, trigger_data, NULL);
936 }
937
938 /**
939 * event_trigger_register - register an event trigger
940 * @cmd_ops: The event_command operations for the trigger
941 * @file: The event file for the trigger's event
942 * @glob: The trigger command string, with optional remove(!) operator
943 * @trigger_data: The trigger_data for the trigger
944 *
945 * Register an event trigger. The @cmd_ops are used to call the
946 * cmd_ops->reg() function which actually does the registration.
947 *
948 * Return: 0 on success, errno otherwise
949 */
950 int event_trigger_register(struct event_command *cmd_ops,
951 struct trace_event_file *file,
952 char *glob,
953 struct event_trigger_data *trigger_data)
954 {
955 return cmd_ops->reg(glob, trigger_data, file);
956 }
957
958 /**
959 * event_trigger_unregister - unregister an event trigger
960 * @cmd_ops: The event_command operations for the trigger
961 * @file: The event file for the trigger's event
962 * @glob: The trigger command string, with optional remove(!) operator
963 * @trigger_data: The trigger_data for the trigger
964 *
965 * Unregister an event trigger. The @cmd_ops are used to call the
966 * cmd_ops->unreg() function which actually does the unregistration.
967 */
968 void event_trigger_unregister(struct event_command *cmd_ops,
969 struct trace_event_file *file,
970 char *glob,
971 struct event_trigger_data *trigger_data)
972 {
973 cmd_ops->unreg(glob, trigger_data, file);
974 }
975
976 /*
977 * End event trigger parsing helper functions.
978 */
979
980 /**
981 * event_trigger_parse - Generic event_command @parse implementation
982 * @cmd_ops: The command ops, used for trigger registration
983 * @file: The trace_event_file associated with the event
984 * @glob: The raw string used to register the trigger
985 * @cmd: The cmd portion of the string used to register the trigger
986 * @param_and_filter: The param and filter portion of the string used to register the trigger
987 *
988 * Common implementation for event command parsing and trigger
989 * instantiation.
990 *
991 * Usually used directly as the @parse method in event command
992 * implementations.
993 *
994 * Return: 0 on success, errno otherwise
995 */
996 static int
997 event_trigger_parse(struct event_command *cmd_ops,
998 struct trace_event_file *file,
999 char *glob, char *cmd, char *param_and_filter)
1000 {
1001 struct event_trigger_data *trigger_data;
1002 char *param, *filter;
1003 bool remove;
1004 int ret;
1005
1006 remove = event_trigger_check_remove(glob);
1007
1008 ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, false);
1009 if (ret)
1010 return ret;
1011
1012 ret = -ENOMEM;
1013 trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
1014 if (!trigger_data)
1015 goto out;
1016
1017 if (remove) {
1018 event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
1019 kfree(trigger_data);
1020 ret = 0;
1021 goto out;
1022 }
1023
1024 ret = event_trigger_parse_num(param, trigger_data);
1025 if (ret)
1026 goto out_free;
1027
1028 ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
1029 if (ret < 0)
1030 goto out_free;
1031
1032 /* Up the trigger_data count to make sure reg doesn't free it on failure */
1033 event_trigger_init(trigger_data);
1034
1035 ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
1036 if (ret)
1037 goto out_free;
1038
1039 /* Down the counter of trigger_data or free it if not used anymore */
1040 event_trigger_free(trigger_data);
1041 out:
1042 return ret;
1043
1044 out_free:
1045 event_trigger_reset_filter(cmd_ops, trigger_data);
1046 kfree(trigger_data);
1047 goto out;
1048 }
1049
1050 /**
1051 * set_trigger_filter - Generic event_command @set_filter implementation
1052 * @filter_str: The filter string for the trigger, NULL to remove filter
1053 * @trigger_data: Trigger-specific data
1054 * @file: The trace_event_file associated with the event
1055 *
1056 * Common implementation for event command filter parsing and filter
1057 * instantiation.
1058 *
1059 * Usually used directly as the @set_filter method in event command
1060 * implementations.
1061 *
1062 * Also used to remove a filter (if filter_str = NULL).
1063 *
1064 * Return: 0 on success, errno otherwise
1065 */
1066 int set_trigger_filter(char *filter_str,
1067 struct event_trigger_data *trigger_data,
1068 struct trace_event_file *file)
1069 {
1070 struct event_trigger_data *data = trigger_data;
1071 struct event_filter *filter = NULL, *tmp;
1072 int ret = -EINVAL;
1073 char *s;
1074
1075 if (!filter_str) /* clear the current filter */
1076 goto assign;
1077
1078 s = strsep(&filter_str, " \t");
1079
1080 if (!strlen(s) || strcmp(s, "if") != 0)
1081 goto out;
1082
1083 if (!filter_str)
1084 goto out;
1085
1086 /* The filter is for the 'trigger' event, not the triggered event */
1087 ret = create_event_filter(file->tr, file->event_call,
1088 filter_str, true, &filter);
1089
1090 /* Only enabled set_str for error handling */
1091 if (filter) {
1092 kfree(filter->filter_string);
1093 filter->filter_string = NULL;
1094 }
1095
1096 /*
1097 * If create_event_filter() fails, filter still needs to be freed.
1098 * Which the calling code will do with data->filter.
1099 */
1100 assign:
1101 tmp = rcu_access_pointer(data->filter);
1102
1103 rcu_assign_pointer(data->filter, filter);
1104
1105 if (tmp) {
1106 /*
1107 * Make sure the call is done with the filter.
1108 * It is possible that a filter could fail at boot up,
1109 * and then this path will be called. Avoid the synchronization
1110 * in that case.
1111 */
1112 if (system_state != SYSTEM_BOOTING)
1113 tracepoint_synchronize_unregister();
1114 free_event_filter(tmp);
1115 }
1116
1117 kfree(data->filter_str);
1118 data->filter_str = NULL;
1119
1120 if (filter_str) {
1121 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
1122 if (!data->filter_str) {
1123 free_event_filter(rcu_access_pointer(data->filter));
1124 data->filter = NULL;
1125 ret = -ENOMEM;
1126 }
1127 }
1128 out:
1129 return ret;
1130 }
1131
1132 static LIST_HEAD(named_triggers);
1133
1134 /**
1135 * find_named_trigger - Find the common named trigger associated with @name
1136 * @name: The name of the set of named triggers to find the common data for
1137 *
1138 * Named triggers are sets of triggers that share a common set of
1139 * trigger data. The first named trigger registered with a given name
1140 * owns the common trigger data that the others subsequently
1141 * registered with the same name will reference. This function
1142 * returns the common trigger data associated with that first
1143 * registered instance.
1144 *
1145 * Return: the common trigger data for the given named trigger on
1146 * success, NULL otherwise.
1147 */
1148 struct event_trigger_data *find_named_trigger(const char *name)
1149 {
1150 struct event_trigger_data *data;
1151
1152 if (!name)
1153 return NULL;
1154
1155 list_for_each_entry(data, &named_triggers, named_list) {
1156 if (data->named_data)
1157 continue;
1158 if (strcmp(data->name, name) == 0)
1159 return data;
1160 }
1161
1162 return NULL;
1163 }
1164
1165 /**
1166 * is_named_trigger - determine if a given trigger is a named trigger
1167 * @test: The trigger data to test
1168 *
1169 * Return: true if 'test' is a named trigger, false otherwise.
1170 */
1171 bool is_named_trigger(struct event_trigger_data *test)
1172 {
1173 struct event_trigger_data *data;
1174
1175 list_for_each_entry(data, &named_triggers, named_list) {
1176 if (test == data)
1177 return true;
1178 }
1179
1180 return false;
1181 }
1182
1183 /**
1184 * save_named_trigger - save the trigger in the named trigger list
1185 * @name: The name of the named trigger set
1186 * @data: The trigger data to save
1187 *
1188 * Return: 0 if successful, negative error otherwise.
1189 */
1190 int save_named_trigger(const char *name, struct event_trigger_data *data)
1191 {
1192 data->name = kstrdup(name, GFP_KERNEL);
1193 if (!data->name)
1194 return -ENOMEM;
1195
1196 list_add(&data->named_list, &named_triggers);
1197
1198 return 0;
1199 }
1200
1201 /**
1202 * del_named_trigger - delete a trigger from the named trigger list
1203 * @data: The trigger data to delete
1204 */
1205 void del_named_trigger(struct event_trigger_data *data)
1206 {
1207 kfree(data->name);
1208 data->name = NULL;
1209
1210 list_del(&data->named_list);
1211 }
1212
1213 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
1214 {
1215 struct event_trigger_data *test;
1216
1217 list_for_each_entry(test, &named_triggers, named_list) {
1218 if (strcmp(test->name, data->name) == 0) {
1219 if (pause) {
1220 test->paused_tmp = test->paused;
1221 test->paused = true;
1222 } else {
1223 test->paused = test->paused_tmp;
1224 }
1225 }
1226 }
1227 }
1228
1229 /**
1230 * pause_named_trigger - Pause all named triggers with the same name
1231 * @data: The trigger data of a named trigger to pause
1232 *
1233 * Pauses a named trigger along with all other triggers having the
1234 * same name. Because named triggers share a common set of data,
1235 * pausing only one is meaningless, so pausing one named trigger needs
1236 * to pause all triggers with the same name.
1237 */
1238 void pause_named_trigger(struct event_trigger_data *data)
1239 {
1240 __pause_named_trigger(data, true);
1241 }
1242
1243 /**
1244 * unpause_named_trigger - Un-pause all named triggers with the same name
1245 * @data: The trigger data of a named trigger to unpause
1246 *
1247 * Un-pauses a named trigger along with all other triggers having the
1248 * same name. Because named triggers share a common set of data,
1249 * unpausing only one is meaningless, so unpausing one named trigger
1250 * needs to unpause all triggers with the same name.
1251 */
1252 void unpause_named_trigger(struct event_trigger_data *data)
1253 {
1254 __pause_named_trigger(data, false);
1255 }
1256
1257 /**
1258 * set_named_trigger_data - Associate common named trigger data
1259 * @data: The trigger data to associate
1260 * @named_data: The common named trigger to be associated
1261 *
1262 * Named triggers are sets of triggers that share a common set of
1263 * trigger data. The first named trigger registered with a given name
1264 * owns the common trigger data that the others subsequently
1265 * registered with the same name will reference. This function
1266 * associates the common trigger data from the first trigger with the
1267 * given trigger.
1268 */
1269 void set_named_trigger_data(struct event_trigger_data *data,
1270 struct event_trigger_data *named_data)
1271 {
1272 data->named_data = named_data;
1273 }
1274
1275 struct event_trigger_data *
1276 get_named_trigger_data(struct event_trigger_data *data)
1277 {
1278 return data->named_data;
1279 }
1280
1281 static void
1282 traceon_trigger(struct event_trigger_data *data,
1283 struct trace_buffer *buffer, void *rec,
1284 struct ring_buffer_event *event)
1285 {
1286 struct trace_event_file *file = data->private_data;
1287
1288 if (file) {
1289 if (tracer_tracing_is_on(file->tr))
1290 return;
1291
1292 tracer_tracing_on(file->tr);
1293 return;
1294 }
1295
1296 if (tracing_is_on())
1297 return;
1298
1299 tracing_on();
1300 }
1301
1302 static void
1303 traceon_count_trigger(struct event_trigger_data *data,
1304 struct trace_buffer *buffer, void *rec,
1305 struct ring_buffer_event *event)
1306 {
1307 struct trace_event_file *file = data->private_data;
1308
1309 if (file) {
1310 if (tracer_tracing_is_on(file->tr))
1311 return;
1312 } else {
1313 if (tracing_is_on())
1314 return;
1315 }
1316
1317 if (!data->count)
1318 return;
1319
1320 if (data->count != -1)
1321 (data->count)--;
1322
1323 if (file)
1324 tracer_tracing_on(file->tr);
1325 else
1326 tracing_on();
1327 }
1328
1329 static void
1330 traceoff_trigger(struct event_trigger_data *data,
1331 struct trace_buffer *buffer, void *rec,
1332 struct ring_buffer_event *event)
1333 {
1334 struct trace_event_file *file = data->private_data;
1335
1336 if (file) {
1337 if (!tracer_tracing_is_on(file->tr))
1338 return;
1339
1340 tracer_tracing_off(file->tr);
1341 return;
1342 }
1343
1344 if (!tracing_is_on())
1345 return;
1346
1347 tracing_off();
1348 }
1349
1350 static void
1351 traceoff_count_trigger(struct event_trigger_data *data,
1352 struct trace_buffer *buffer, void *rec,
1353 struct ring_buffer_event *event)
1354 {
1355 struct trace_event_file *file = data->private_data;
1356
1357 if (file) {
1358 if (!tracer_tracing_is_on(file->tr))
1359 return;
1360 } else {
1361 if (!tracing_is_on())
1362 return;
1363 }
1364
1365 if (!data->count)
1366 return;
1367
1368 if (data->count != -1)
1369 (data->count)--;
1370
1371 if (file)
1372 tracer_tracing_off(file->tr);
1373 else
1374 tracing_off();
1375 }
1376
1377 static int
1378 traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1379 {
1380 return event_trigger_print("traceon", m, (void *)data->count,
1381 data->filter_str);
1382 }
1383
1384 static int
1385 traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1386 {
1387 return event_trigger_print("traceoff", m, (void *)data->count,
1388 data->filter_str);
1389 }
1390
1391 static struct event_trigger_ops traceon_trigger_ops = {
1392 .trigger = traceon_trigger,
1393 .print = traceon_trigger_print,
1394 .init = event_trigger_init,
1395 .free = event_trigger_free,
1396 };
1397
1398 static struct event_trigger_ops traceon_count_trigger_ops = {
1399 .trigger = traceon_count_trigger,
1400 .print = traceon_trigger_print,
1401 .init = event_trigger_init,
1402 .free = event_trigger_free,
1403 };
1404
1405 static struct event_trigger_ops traceoff_trigger_ops = {
1406 .trigger = traceoff_trigger,
1407 .print = traceoff_trigger_print,
1408 .init = event_trigger_init,
1409 .free = event_trigger_free,
1410 };
1411
1412 static struct event_trigger_ops traceoff_count_trigger_ops = {
1413 .trigger = traceoff_count_trigger,
1414 .print = traceoff_trigger_print,
1415 .init = event_trigger_init,
1416 .free = event_trigger_free,
1417 };
1418
1419 static struct event_trigger_ops *
1420 onoff_get_trigger_ops(char *cmd, char *param)
1421 {
1422 struct event_trigger_ops *ops;
1423
1424 /* we register both traceon and traceoff to this callback */
1425 if (strcmp(cmd, "traceon") == 0)
1426 ops = param ? &traceon_count_trigger_ops :
1427 &traceon_trigger_ops;
1428 else
1429 ops = param ? &traceoff_count_trigger_ops :
1430 &traceoff_trigger_ops;
1431
1432 return ops;
1433 }
1434
1435 static struct event_command trigger_traceon_cmd = {
1436 .name = "traceon",
1437 .trigger_type = ETT_TRACE_ONOFF,
1438 .parse = event_trigger_parse,
1439 .reg = register_trigger,
1440 .unreg = unregister_trigger,
1441 .get_trigger_ops = onoff_get_trigger_ops,
1442 .set_filter = set_trigger_filter,
1443 };
1444
1445 static struct event_command trigger_traceoff_cmd = {
1446 .name = "traceoff",
1447 .trigger_type = ETT_TRACE_ONOFF,
1448 .flags = EVENT_CMD_FL_POST_TRIGGER,
1449 .parse = event_trigger_parse,
1450 .reg = register_trigger,
1451 .unreg = unregister_trigger,
1452 .get_trigger_ops = onoff_get_trigger_ops,
1453 .set_filter = set_trigger_filter,
1454 };
1455
1456 #ifdef CONFIG_TRACER_SNAPSHOT
1457 static void
1458 snapshot_trigger(struct event_trigger_data *data,
1459 struct trace_buffer *buffer, void *rec,
1460 struct ring_buffer_event *event)
1461 {
1462 struct trace_event_file *file = data->private_data;
1463
1464 if (file)
1465 tracing_snapshot_instance(file->tr);
1466 else
1467 tracing_snapshot();
1468 }
1469
1470 static void
1471 snapshot_count_trigger(struct event_trigger_data *data,
1472 struct trace_buffer *buffer, void *rec,
1473 struct ring_buffer_event *event)
1474 {
1475 if (!data->count)
1476 return;
1477
1478 if (data->count != -1)
1479 (data->count)--;
1480
1481 snapshot_trigger(data, buffer, rec, event);
1482 }
1483
1484 static int
1485 register_snapshot_trigger(char *glob,
1486 struct event_trigger_data *data,
1487 struct trace_event_file *file)
1488 {
1489 int ret = tracing_arm_snapshot(file->tr);
1490
1491 if (ret < 0)
1492 return ret;
1493
1494 ret = register_trigger(glob, data, file);
1495 if (ret < 0)
1496 tracing_disarm_snapshot(file->tr);
1497 return ret;
1498 }
1499
1500 static void unregister_snapshot_trigger(char *glob,
1501 struct event_trigger_data *data,
1502 struct trace_event_file *file)
1503 {
1504 if (try_unregister_trigger(glob, data, file))
1505 tracing_disarm_snapshot(file->tr);
1506 }
1507
1508 static int
1509 snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1510 {
1511 return event_trigger_print("snapshot", m, (void *)data->count,
1512 data->filter_str);
1513 }
1514
1515 static struct event_trigger_ops snapshot_trigger_ops = {
1516 .trigger = snapshot_trigger,
1517 .print = snapshot_trigger_print,
1518 .init = event_trigger_init,
1519 .free = event_trigger_free,
1520 };
1521
1522 static struct event_trigger_ops snapshot_count_trigger_ops = {
1523 .trigger = snapshot_count_trigger,
1524 .print = snapshot_trigger_print,
1525 .init = event_trigger_init,
1526 .free = event_trigger_free,
1527 };
1528
1529 static struct event_trigger_ops *
1530 snapshot_get_trigger_ops(char *cmd, char *param)
1531 {
1532 return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1533 }
1534
1535 static struct event_command trigger_snapshot_cmd = {
1536 .name = "snapshot",
1537 .trigger_type = ETT_SNAPSHOT,
1538 .parse = event_trigger_parse,
1539 .reg = register_snapshot_trigger,
1540 .unreg = unregister_snapshot_trigger,
1541 .get_trigger_ops = snapshot_get_trigger_ops,
1542 .set_filter = set_trigger_filter,
1543 };
1544
1545 static __init int register_trigger_snapshot_cmd(void)
1546 {
1547 int ret;
1548
1549 ret = register_event_command(&trigger_snapshot_cmd);
1550 WARN_ON(ret < 0);
1551
1552 return ret;
1553 }
1554 #else
1555 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1556 #endif /* CONFIG_TRACER_SNAPSHOT */
1557
1558 #ifdef CONFIG_STACKTRACE
1559 #ifdef CONFIG_UNWINDER_ORC
1560 /* Skip 2:
1561 * event_triggers_post_call()
1562 * trace_event_raw_event_xxx()
1563 */
1564 # define STACK_SKIP 2
1565 #else
1566 /*
1567 * Skip 4:
1568 * stacktrace_trigger()
1569 * event_triggers_post_call()
1570 * trace_event_buffer_commit()
1571 * trace_event_raw_event_xxx()
1572 */
1573 #define STACK_SKIP 4
1574 #endif
1575
1576 static void
1577 stacktrace_trigger(struct event_trigger_data *data,
1578 struct trace_buffer *buffer, void *rec,
1579 struct ring_buffer_event *event)
1580 {
1581 struct trace_event_file *file = data->private_data;
1582
1583 if (file)
1584 __trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
1585 else
1586 trace_dump_stack(STACK_SKIP);
1587 }
1588
1589 static void
1590 stacktrace_count_trigger(struct event_trigger_data *data,
1591 struct trace_buffer *buffer, void *rec,
1592 struct ring_buffer_event *event)
1593 {
1594 if (!data->count)
1595 return;
1596
1597 if (data->count != -1)
1598 (data->count)--;
1599
1600 stacktrace_trigger(data, buffer, rec, event);
1601 }
1602
1603 static int
1604 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1605 {
1606 return event_trigger_print("stacktrace", m, (void *)data->count,
1607 data->filter_str);
1608 }
1609
1610 static struct event_trigger_ops stacktrace_trigger_ops = {
1611 .trigger = stacktrace_trigger,
1612 .print = stacktrace_trigger_print,
1613 .init = event_trigger_init,
1614 .free = event_trigger_free,
1615 };
1616
1617 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1618 .trigger = stacktrace_count_trigger,
1619 .print = stacktrace_trigger_print,
1620 .init = event_trigger_init,
1621 .free = event_trigger_free,
1622 };
1623
1624 static struct event_trigger_ops *
1625 stacktrace_get_trigger_ops(char *cmd, char *param)
1626 {
1627 return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1628 }
1629
1630 static struct event_command trigger_stacktrace_cmd = {
1631 .name = "stacktrace",
1632 .trigger_type = ETT_STACKTRACE,
1633 .flags = EVENT_CMD_FL_POST_TRIGGER,
1634 .parse = event_trigger_parse,
1635 .reg = register_trigger,
1636 .unreg = unregister_trigger,
1637 .get_trigger_ops = stacktrace_get_trigger_ops,
1638 .set_filter = set_trigger_filter,
1639 };
1640
1641 static __init int register_trigger_stacktrace_cmd(void)
1642 {
1643 int ret;
1644
1645 ret = register_event_command(&trigger_stacktrace_cmd);
1646 WARN_ON(ret < 0);
1647
1648 return ret;
1649 }
1650 #else
1651 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1652 #endif /* CONFIG_STACKTRACE */
1653
1654 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1655 {
1656 unregister_event_command(&trigger_traceon_cmd);
1657 unregister_event_command(&trigger_traceoff_cmd);
1658 }
1659
1660 static void
1661 event_enable_trigger(struct event_trigger_data *data,
1662 struct trace_buffer *buffer, void *rec,
1663 struct ring_buffer_event *event)
1664 {
1665 struct enable_trigger_data *enable_data = data->private_data;
1666
1667 if (enable_data->enable)
1668 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1669 else
1670 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1671 }
1672
1673 static void
1674 event_enable_count_trigger(struct event_trigger_data *data,
1675 struct trace_buffer *buffer, void *rec,
1676 struct ring_buffer_event *event)
1677 {
1678 struct enable_trigger_data *enable_data = data->private_data;
1679
1680 if (!data->count)
1681 return;
1682
1683 /* Skip if the event is in a state we want to switch to */
1684 if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1685 return;
1686
1687 if (data->count != -1)
1688 (data->count)--;
1689
1690 event_enable_trigger(data, buffer, rec, event);
1691 }
1692
1693 int event_enable_trigger_print(struct seq_file *m,
1694 struct event_trigger_data *data)
1695 {
1696 struct enable_trigger_data *enable_data = data->private_data;
1697
1698 seq_printf(m, "%s:%s:%s",
1699 enable_data->hist ?
1700 (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1701 (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1702 enable_data->file->event_call->class->system,
1703 trace_event_name(enable_data->file->event_call));
1704
1705 if (data->count == -1)
1706 seq_puts(m, ":unlimited");
1707 else
1708 seq_printf(m, ":count=%ld", data->count);
1709
1710 if (data->filter_str)
1711 seq_printf(m, " if %s\n", data->filter_str);
1712 else
1713 seq_putc(m, '\n');
1714
1715 return 0;
1716 }
1717
1718 void event_enable_trigger_free(struct event_trigger_data *data)
1719 {
1720 struct enable_trigger_data *enable_data = data->private_data;
1721
1722 if (WARN_ON_ONCE(data->ref <= 0))
1723 return;
1724
1725 data->ref--;
1726 if (!data->ref) {
1727 /* Remove the SOFT_MODE flag */
1728 trace_event_enable_disable(enable_data->file, 0, 1);
1729 trace_event_put_ref(enable_data->file->event_call);
1730 trigger_data_free(data);
1731 kfree(enable_data);
1732 }
1733 }
1734
1735 static struct event_trigger_ops event_enable_trigger_ops = {
1736 .trigger = event_enable_trigger,
1737 .print = event_enable_trigger_print,
1738 .init = event_trigger_init,
1739 .free = event_enable_trigger_free,
1740 };
1741
1742 static struct event_trigger_ops event_enable_count_trigger_ops = {
1743 .trigger = event_enable_count_trigger,
1744 .print = event_enable_trigger_print,
1745 .init = event_trigger_init,
1746 .free = event_enable_trigger_free,
1747 };
1748
1749 static struct event_trigger_ops event_disable_trigger_ops = {
1750 .trigger = event_enable_trigger,
1751 .print = event_enable_trigger_print,
1752 .init = event_trigger_init,
1753 .free = event_enable_trigger_free,
1754 };
1755
1756 static struct event_trigger_ops event_disable_count_trigger_ops = {
1757 .trigger = event_enable_count_trigger,
1758 .print = event_enable_trigger_print,
1759 .init = event_trigger_init,
1760 .free = event_enable_trigger_free,
1761 };
1762
1763 int event_enable_trigger_parse(struct event_command *cmd_ops,
1764 struct trace_event_file *file,
1765 char *glob, char *cmd, char *param_and_filter)
1766 {
1767 struct trace_event_file *event_enable_file;
1768 struct enable_trigger_data *enable_data;
1769 struct event_trigger_data *trigger_data;
1770 struct trace_array *tr = file->tr;
1771 char *param, *filter;
1772 bool enable, remove;
1773 const char *system;
1774 const char *event;
1775 bool hist = false;
1776 int ret;
1777
1778 remove = event_trigger_check_remove(glob);
1779
1780 if (event_trigger_empty_param(param_and_filter))
1781 return -EINVAL;
1782
1783 ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, true);
1784 if (ret)
1785 return ret;
1786
1787 system = strsep(¶m, ":");
1788 if (!param)
1789 return -EINVAL;
1790
1791 event = strsep(¶m, ":");
1792
1793 ret = -EINVAL;
1794 event_enable_file = find_event_file(tr, system, event);
1795 if (!event_enable_file)
1796 goto out;
1797
1798 #ifdef CONFIG_HIST_TRIGGERS
1799 hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1800 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1801
1802 enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1803 (strcmp(cmd, ENABLE_HIST_STR) == 0));
1804 #else
1805 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1806 #endif
1807 ret = -ENOMEM;
1808
1809 enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1810 if (!enable_data)
1811 goto out;
1812
1813 enable_data->hist = hist;
1814 enable_data->enable = enable;
1815 enable_data->file = event_enable_file;
1816
1817 trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
1818 if (!trigger_data) {
1819 kfree(enable_data);
1820 goto out;
1821 }
1822
1823 if (remove) {
1824 event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
1825 kfree(trigger_data);
1826 kfree(enable_data);
1827 ret = 0;
1828 goto out;
1829 }
1830
1831 /* Up the trigger_data count to make sure nothing frees it on failure */
1832 event_trigger_init(trigger_data);
1833
1834 ret = event_trigger_parse_num(param, trigger_data);
1835 if (ret)
1836 goto out_free;
1837
1838 ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
1839 if (ret < 0)
1840 goto out_free;
1841
1842 /* Don't let event modules unload while probe registered */
1843 ret = trace_event_try_get_ref(event_enable_file->event_call);
1844 if (!ret) {
1845 ret = -EBUSY;
1846 goto out_free;
1847 }
1848
1849 ret = trace_event_enable_disable(event_enable_file, 1, 1);
1850 if (ret < 0)
1851 goto out_put;
1852
1853 ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
1854 if (ret)
1855 goto out_disable;
1856
1857 event_trigger_free(trigger_data);
1858 out:
1859 return ret;
1860 out_disable:
1861 trace_event_enable_disable(event_enable_file, 0, 1);
1862 out_put:
1863 trace_event_put_ref(event_enable_file->event_call);
1864 out_free:
1865 event_trigger_reset_filter(cmd_ops, trigger_data);
1866 event_trigger_free(trigger_data);
1867 kfree(enable_data);
1868
1869 goto out;
1870 }
1871
1872 int event_enable_register_trigger(char *glob,
1873 struct event_trigger_data *data,
1874 struct trace_event_file *file)
1875 {
1876 struct enable_trigger_data *enable_data = data->private_data;
1877 struct enable_trigger_data *test_enable_data;
1878 struct event_trigger_data *test;
1879 int ret = 0;
1880
1881 lockdep_assert_held(&event_mutex);
1882
1883 list_for_each_entry(test, &file->triggers, list) {
1884 test_enable_data = test->private_data;
1885 if (test_enable_data &&
1886 (test->cmd_ops->trigger_type ==
1887 data->cmd_ops->trigger_type) &&
1888 (test_enable_data->file == enable_data->file)) {
1889 ret = -EEXIST;
1890 goto out;
1891 }
1892 }
1893
1894 if (data->ops->init) {
1895 ret = data->ops->init(data);
1896 if (ret < 0)
1897 goto out;
1898 }
1899
1900 list_add_rcu(&data->list, &file->triggers);
1901
1902 update_cond_flag(file);
1903 ret = trace_event_trigger_enable_disable(file, 1);
1904 if (ret < 0) {
1905 list_del_rcu(&data->list);
1906 update_cond_flag(file);
1907 }
1908 out:
1909 return ret;
1910 }
1911
1912 void event_enable_unregister_trigger(char *glob,
1913 struct event_trigger_data *test,
1914 struct trace_event_file *file)
1915 {
1916 struct enable_trigger_data *test_enable_data = test->private_data;
1917 struct event_trigger_data *data = NULL, *iter;
1918 struct enable_trigger_data *enable_data;
1919
1920 lockdep_assert_held(&event_mutex);
1921
1922 list_for_each_entry(iter, &file->triggers, list) {
1923 enable_data = iter->private_data;
1924 if (enable_data &&
1925 (iter->cmd_ops->trigger_type ==
1926 test->cmd_ops->trigger_type) &&
1927 (enable_data->file == test_enable_data->file)) {
1928 data = iter;
1929 list_del_rcu(&data->list);
1930 trace_event_trigger_enable_disable(file, 0);
1931 update_cond_flag(file);
1932 break;
1933 }
1934 }
1935
1936 if (data && data->ops->free)
1937 data->ops->free(data);
1938 }
1939
1940 static struct event_trigger_ops *
1941 event_enable_get_trigger_ops(char *cmd, char *param)
1942 {
1943 struct event_trigger_ops *ops;
1944 bool enable;
1945
1946 #ifdef CONFIG_HIST_TRIGGERS
1947 enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1948 (strcmp(cmd, ENABLE_HIST_STR) == 0));
1949 #else
1950 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1951 #endif
1952 if (enable)
1953 ops = param ? &event_enable_count_trigger_ops :
1954 &event_enable_trigger_ops;
1955 else
1956 ops = param ? &event_disable_count_trigger_ops :
1957 &event_disable_trigger_ops;
1958
1959 return ops;
1960 }
1961
1962 static struct event_command trigger_enable_cmd = {
1963 .name = ENABLE_EVENT_STR,
1964 .trigger_type = ETT_EVENT_ENABLE,
1965 .parse = event_enable_trigger_parse,
1966 .reg = event_enable_register_trigger,
1967 .unreg = event_enable_unregister_trigger,
1968 .get_trigger_ops = event_enable_get_trigger_ops,
1969 .set_filter = set_trigger_filter,
1970 };
1971
1972 static struct event_command trigger_disable_cmd = {
1973 .name = DISABLE_EVENT_STR,
1974 .trigger_type = ETT_EVENT_ENABLE,
1975 .parse = event_enable_trigger_parse,
1976 .reg = event_enable_register_trigger,
1977 .unreg = event_enable_unregister_trigger,
1978 .get_trigger_ops = event_enable_get_trigger_ops,
1979 .set_filter = set_trigger_filter,
1980 };
1981
1982 static __init void unregister_trigger_enable_disable_cmds(void)
1983 {
1984 unregister_event_command(&trigger_enable_cmd);
1985 unregister_event_command(&trigger_disable_cmd);
1986 }
1987
1988 static __init int register_trigger_enable_disable_cmds(void)
1989 {
1990 int ret;
1991
1992 ret = register_event_command(&trigger_enable_cmd);
1993 if (WARN_ON(ret < 0))
1994 return ret;
1995 ret = register_event_command(&trigger_disable_cmd);
1996 if (WARN_ON(ret < 0))
1997 unregister_trigger_enable_disable_cmds();
1998
1999 return ret;
2000 }
2001
2002 static __init int register_trigger_traceon_traceoff_cmds(void)
2003 {
2004 int ret;
2005
2006 ret = register_event_command(&trigger_traceon_cmd);
2007 if (WARN_ON(ret < 0))
2008 return ret;
2009 ret = register_event_command(&trigger_traceoff_cmd);
2010 if (WARN_ON(ret < 0))
2011 unregister_trigger_traceon_traceoff_cmds();
2012
2013 return ret;
2014 }
2015
2016 __init int register_trigger_cmds(void)
2017 {
2018 register_trigger_traceon_traceoff_cmds();
2019 register_trigger_snapshot_cmd();
2020 register_trigger_stacktrace_cmd();
2021 register_trigger_enable_disable_cmds();
2022 register_trigger_hist_enable_disable_cmds();
2023 register_trigger_hist_cmd();
2024
2025 return 0;
2026 }
2027
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