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