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