kernel/trace/trace_events_trigger.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_trigger - trace event triggers
   4  *
   5  * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
   6  */
   7
   8 #include <linux/security.h>
   9 #include <linux/module.h>
  10 #include <linux/ctype.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/rculist.h>
  14
  15 #include "trace.h"
  16
  17 static LIST_HEAD(trigger_commands);
  18 static DEFINE_MUTEX(trigger_cmd_mutex);
  19
  20 void trigger_data_free(struct event_trigger_data *data)
  21 {
  22         if (data->cmd_ops->set_filter)
  23                 data->cmd_ops->set_filter(NULL, data, NULL);
  24
  25         /* make sure current triggers exit before free */
  26         tracepoint_synchronize_unregister();
  27
  28         kfree(data);
  29 }
  30
  31 /**
  32  * event_triggers_call - Call triggers associated with a trace event
  33  * @file: The trace_event_file associated with the event
  34  * @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  */
  55 enum event_trigger_type
  56 event_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 }
  85 EXPORT_SYMBOL_GPL(event_triggers_call);
  86
  87 bool __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 }
  99 EXPORT_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  */
 113 void
 114 event_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 }
 126 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 127
 128 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 129
 130 static 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
 141 static 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
 154 static 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
 170 static void trigger_stop(struct seq_file *m, void *t)
 171 {
 172         mutex_unlock(&event_mutex);
 173 }
 174
 175 static 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
 197 static 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
 204 static 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
 245 int 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
 273 static 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
 313 static 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
 325 static ssize_t
 326 event_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
 332 static int
 333 event_trigger_open(struct inode *inode, struct file *filp)
 334 {
 335         /* Checks for tracefs lockdown */
 336         return event_trigger_regex_open(inode, filp);
 337 }
 338
 339 static int
 340 event_trigger_release(struct inode *inode, struct file *file)
 341 {
 342         return event_trigger_regex_release(inode, file);
 343 }
 344
 345 const 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  */
 413 static int
 414 event_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  */
 445 int 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  */
 460 static void
 461 event_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
 471 int 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  */
 504 void
 505 clear_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  */
 530 void 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  */
 564 static 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         }
 594 out:
 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  */
 609 static 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  */
 718 bool 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  */
 735 bool 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  */
 766 int 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         }
 805 out:
 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  */
 825 struct 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  */
 861 int 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  */
 895 int 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  */
 913 void 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  */
 932 int 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  */
 950 void 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  */
 978 static int
 979 event_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  */
1048 int 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, false, &filter);
1071         /*
1072          * If create_event_filter() fails, filter still needs to be freed.
1073          * Which the calling code will do with data->filter.
1074          */
1075  assign:
1076         tmp = rcu_access_pointer(data->filter);
1077
1078         rcu_assign_pointer(data->filter, filter);
1079
1080         if (tmp) {
1081                 /* Make sure the call is done with the filter */
1082                 tracepoint_synchronize_unregister();
1083                 free_event_filter(tmp);
1084         }
1085
1086         kfree(data->filter_str);
1087         data->filter_str = NULL;
1088
1089         if (filter_str) {
1090                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
1091                 if (!data->filter_str) {
1092                         free_event_filter(rcu_access_pointer(data->filter));
1093                         data->filter = NULL;
1094                         ret = -ENOMEM;
1095                 }
1096         }
1097  out:
1098         return ret;
1099 }
1100
1101 static LIST_HEAD(named_triggers);
1102
1103 /**
1104  * find_named_trigger - Find the common named trigger associated with @name
1105  * @name: The name of the set of named triggers to find the common data for
1106  *
1107  * Named triggers are sets of triggers that share a common set of
1108  * trigger data.  The first named trigger registered with a given name
1109  * owns the common trigger data that the others subsequently
1110  * registered with the same name will reference.  This function
1111  * returns the common trigger data associated with that first
1112  * registered instance.
1113  *
1114  * Return: the common trigger data for the given named trigger on
1115  * success, NULL otherwise.
1116  */
1117 struct event_trigger_data *find_named_trigger(const char *name)
1118 {
1119         struct event_trigger_data *data;
1120
1121         if (!name)
1122                 return NULL;
1123
1124         list_for_each_entry(data, &named_triggers, named_list) {
1125                 if (data->named_data)
1126                         continue;
1127                 if (strcmp(data->name, name) == 0)
1128                         return data;
1129         }
1130
1131         return NULL;
1132 }
1133
1134 /**
1135  * is_named_trigger - determine if a given trigger is a named trigger
1136  * @test: The trigger data to test
1137  *
1138  * Return: true if 'test' is a named trigger, false otherwise.
1139  */
1140 bool is_named_trigger(struct event_trigger_data *test)
1141 {
1142         struct event_trigger_data *data;
1143
1144         list_for_each_entry(data, &named_triggers, named_list) {
1145                 if (test == data)
1146                         return true;
1147         }
1148
1149         return false;
1150 }
1151
1152 /**
1153  * save_named_trigger - save the trigger in the named trigger list
1154  * @name: The name of the named trigger set
1155  * @data: The trigger data to save
1156  *
1157  * Return: 0 if successful, negative error otherwise.
1158  */
1159 int save_named_trigger(const char *name, struct event_trigger_data *data)
1160 {
1161         data->name = kstrdup(name, GFP_KERNEL);
1162         if (!data->name)
1163                 return -ENOMEM;
1164
1165         list_add(&data->named_list, &named_triggers);
1166
1167         return 0;
1168 }
1169
1170 /**
1171  * del_named_trigger - delete a trigger from the named trigger list
1172  * @data: The trigger data to delete
1173  */
1174 void del_named_trigger(struct event_trigger_data *data)
1175 {
1176         kfree(data->name);
1177         data->name = NULL;
1178
1179         list_del(&data->named_list);
1180 }
1181
1182 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
1183 {
1184         struct event_trigger_data *test;
1185
1186         list_for_each_entry(test, &named_triggers, named_list) {
1187                 if (strcmp(test->name, data->name) == 0) {
1188                         if (pause) {
1189                                 test->paused_tmp = test->paused;
1190                                 test->paused = true;
1191                         } else {
1192                                 test->paused = test->paused_tmp;
1193                         }
1194                 }
1195         }
1196 }
1197
1198 /**
1199  * pause_named_trigger - Pause all named triggers with the same name
1200  * @data: The trigger data of a named trigger to pause
1201  *
1202  * Pauses a named trigger along with all other triggers having the
1203  * same name.  Because named triggers share a common set of data,
1204  * pausing only one is meaningless, so pausing one named trigger needs
1205  * to pause all triggers with the same name.
1206  */
1207 void pause_named_trigger(struct event_trigger_data *data)
1208 {
1209         __pause_named_trigger(data, true);
1210 }
1211
1212 /**
1213  * unpause_named_trigger - Un-pause all named triggers with the same name
1214  * @data: The trigger data of a named trigger to unpause
1215  *
1216  * Un-pauses a named trigger along with all other triggers having the
1217  * same name.  Because named triggers share a common set of data,
1218  * unpausing only one is meaningless, so unpausing one named trigger
1219  * needs to unpause all triggers with the same name.
1220  */
1221 void unpause_named_trigger(struct event_trigger_data *data)
1222 {
1223         __pause_named_trigger(data, false);
1224 }
1225
1226 /**
1227  * set_named_trigger_data - Associate common named trigger data
1228  * @data: The trigger data to associate
1229  * @named_data: The common named trigger to be associated
1230  *
1231  * Named triggers are sets of triggers that share a common set of
1232  * trigger data.  The first named trigger registered with a given name
1233  * owns the common trigger data that the others subsequently
1234  * registered with the same name will reference.  This function
1235  * associates the common trigger data from the first trigger with the
1236  * given trigger.
1237  */
1238 void set_named_trigger_data(struct event_trigger_data *data,
1239                             struct event_trigger_data *named_data)
1240 {
1241         data->named_data = named_data;
1242 }
1243
1244 struct event_trigger_data *
1245 get_named_trigger_data(struct event_trigger_data *data)
1246 {
1247         return data->named_data;
1248 }
1249
1250 static void
1251 traceon_trigger(struct event_trigger_data *data,
1252                 struct trace_buffer *buffer, void *rec,
1253                 struct ring_buffer_event *event)
1254 {
1255         struct trace_event_file *file = data->private_data;
1256
1257         if (file) {
1258                 if (tracer_tracing_is_on(file->tr))
1259                         return;
1260
1261                 tracer_tracing_on(file->tr);
1262                 return;
1263         }
1264
1265         if (tracing_is_on())
1266                 return;
1267
1268         tracing_on();
1269 }
1270
1271 static void
1272 traceon_count_trigger(struct event_trigger_data *data,
1273                       struct trace_buffer *buffer, void *rec,
1274                       struct ring_buffer_event *event)
1275 {
1276         struct trace_event_file *file = data->private_data;
1277
1278         if (file) {
1279                 if (tracer_tracing_is_on(file->tr))
1280                         return;
1281         } else {
1282                 if (tracing_is_on())
1283                         return;
1284         }
1285
1286         if (!data->count)
1287                 return;
1288
1289         if (data->count != -1)
1290                 (data->count)--;
1291
1292         if (file)
1293                 tracer_tracing_on(file->tr);
1294         else
1295                 tracing_on();
1296 }
1297
1298 static void
1299 traceoff_trigger(struct event_trigger_data *data,
1300                  struct trace_buffer *buffer, void *rec,
1301                  struct ring_buffer_event *event)
1302 {
1303         struct trace_event_file *file = data->private_data;
1304
1305         if (file) {
1306                 if (!tracer_tracing_is_on(file->tr))
1307                         return;
1308
1309                 tracer_tracing_off(file->tr);
1310                 return;
1311         }
1312
1313         if (!tracing_is_on())
1314                 return;
1315
1316         tracing_off();
1317 }
1318
1319 static void
1320 traceoff_count_trigger(struct event_trigger_data *data,
1321                        struct trace_buffer *buffer, void *rec,
1322                        struct ring_buffer_event *event)
1323 {
1324         struct trace_event_file *file = data->private_data;
1325
1326         if (file) {
1327                 if (!tracer_tracing_is_on(file->tr))
1328                         return;
1329         } else {
1330                 if (!tracing_is_on())
1331                         return;
1332         }
1333
1334         if (!data->count)
1335                 return;
1336
1337         if (data->count != -1)
1338                 (data->count)--;
1339
1340         if (file)
1341                 tracer_tracing_off(file->tr);
1342         else
1343                 tracing_off();
1344 }
1345
1346 static int
1347 traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1348 {
1349         return event_trigger_print("traceon", m, (void *)data->count,
1350                                    data->filter_str);
1351 }
1352
1353 static int
1354 traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1355 {
1356         return event_trigger_print("traceoff", m, (void *)data->count,
1357                                    data->filter_str);
1358 }
1359
1360 static struct event_trigger_ops traceon_trigger_ops = {
1361         .trigger                = traceon_trigger,
1362         .print                  = traceon_trigger_print,
1363         .init                   = event_trigger_init,
1364         .free                   = event_trigger_free,
1365 };
1366
1367 static struct event_trigger_ops traceon_count_trigger_ops = {
1368         .trigger                = traceon_count_trigger,
1369         .print                  = traceon_trigger_print,
1370         .init                   = event_trigger_init,
1371         .free                   = event_trigger_free,
1372 };
1373
1374 static struct event_trigger_ops traceoff_trigger_ops = {
1375         .trigger                = traceoff_trigger,
1376         .print                  = traceoff_trigger_print,
1377         .init                   = event_trigger_init,
1378         .free                   = event_trigger_free,
1379 };
1380
1381 static struct event_trigger_ops traceoff_count_trigger_ops = {
1382         .trigger                = traceoff_count_trigger,
1383         .print                  = traceoff_trigger_print,
1384         .init                   = event_trigger_init,
1385         .free                   = event_trigger_free,
1386 };
1387
1388 static struct event_trigger_ops *
1389 onoff_get_trigger_ops(char *cmd, char *param)
1390 {
1391         struct event_trigger_ops *ops;
1392
1393         /* we register both traceon and traceoff to this callback */
1394         if (strcmp(cmd, "traceon") == 0)
1395                 ops = param ? &traceon_count_trigger_ops :
1396                         &traceon_trigger_ops;
1397         else
1398                 ops = param ? &traceoff_count_trigger_ops :
1399                         &traceoff_trigger_ops;
1400
1401         return ops;
1402 }
1403
1404 static struct event_command trigger_traceon_cmd = {
1405         .name                   = "traceon",
1406         .trigger_type           = ETT_TRACE_ONOFF,
1407         .parse                  = event_trigger_parse,
1408         .reg                    = register_trigger,
1409         .unreg                  = unregister_trigger,
1410         .get_trigger_ops        = onoff_get_trigger_ops,
1411         .set_filter             = set_trigger_filter,
1412 };
1413
1414 static struct event_command trigger_traceoff_cmd = {
1415         .name                   = "traceoff",
1416         .trigger_type           = ETT_TRACE_ONOFF,
1417         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1418         .parse                  = event_trigger_parse,
1419         .reg                    = register_trigger,
1420         .unreg                  = unregister_trigger,
1421         .get_trigger_ops        = onoff_get_trigger_ops,
1422         .set_filter             = set_trigger_filter,
1423 };
1424
1425 #ifdef CONFIG_TRACER_SNAPSHOT
1426 static void
1427 snapshot_trigger(struct event_trigger_data *data,
1428                  struct trace_buffer *buffer, void *rec,
1429                  struct ring_buffer_event *event)
1430 {
1431         struct trace_event_file *file = data->private_data;
1432
1433         if (file)
1434                 tracing_snapshot_instance(file->tr);
1435         else
1436                 tracing_snapshot();
1437 }
1438
1439 static void
1440 snapshot_count_trigger(struct event_trigger_data *data,
1441                        struct trace_buffer *buffer, void *rec,
1442                        struct ring_buffer_event *event)
1443 {
1444         if (!data->count)
1445                 return;
1446
1447         if (data->count != -1)
1448                 (data->count)--;
1449
1450         snapshot_trigger(data, buffer, rec, event);
1451 }
1452
1453 static int
1454 register_snapshot_trigger(char *glob,
1455                           struct event_trigger_data *data,
1456                           struct trace_event_file *file)
1457 {
1458         if (tracing_alloc_snapshot_instance(file->tr) != 0)
1459                 return 0;
1460
1461         return register_trigger(glob, data, file);
1462 }
1463
1464 static int
1465 snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1466 {
1467         return event_trigger_print("snapshot", m, (void *)data->count,
1468                                    data->filter_str);
1469 }
1470
1471 static struct event_trigger_ops snapshot_trigger_ops = {
1472         .trigger                = snapshot_trigger,
1473         .print                  = snapshot_trigger_print,
1474         .init                   = event_trigger_init,
1475         .free                   = event_trigger_free,
1476 };
1477
1478 static struct event_trigger_ops snapshot_count_trigger_ops = {
1479         .trigger                = snapshot_count_trigger,
1480         .print                  = snapshot_trigger_print,
1481         .init                   = event_trigger_init,
1482         .free                   = event_trigger_free,
1483 };
1484
1485 static struct event_trigger_ops *
1486 snapshot_get_trigger_ops(char *cmd, char *param)
1487 {
1488         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1489 }
1490
1491 static struct event_command trigger_snapshot_cmd = {
1492         .name                   = "snapshot",
1493         .trigger_type           = ETT_SNAPSHOT,
1494         .parse                  = event_trigger_parse,
1495         .reg                    = register_snapshot_trigger,
1496         .unreg                  = unregister_trigger,
1497         .get_trigger_ops        = snapshot_get_trigger_ops,
1498         .set_filter             = set_trigger_filter,
1499 };
1500
1501 static __init int register_trigger_snapshot_cmd(void)
1502 {
1503         int ret;
1504
1505         ret = register_event_command(&trigger_snapshot_cmd);
1506         WARN_ON(ret < 0);
1507
1508         return ret;
1509 }
1510 #else
1511 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1512 #endif /* CONFIG_TRACER_SNAPSHOT */
1513
1514 #ifdef CONFIG_STACKTRACE
1515 #ifdef CONFIG_UNWINDER_ORC
1516 /* Skip 2:
1517  *   event_triggers_post_call()
1518  *   trace_event_raw_event_xxx()
1519  */
1520 # define STACK_SKIP 2
1521 #else
1522 /*
1523  * Skip 4:
1524  *   stacktrace_trigger()
1525  *   event_triggers_post_call()
1526  *   trace_event_buffer_commit()
1527  *   trace_event_raw_event_xxx()
1528  */
1529 #define STACK_SKIP 4
1530 #endif
1531
1532 static void
1533 stacktrace_trigger(struct event_trigger_data *data,
1534                    struct trace_buffer *buffer,  void *rec,
1535                    struct ring_buffer_event *event)
1536 {
1537         struct trace_event_file *file = data->private_data;
1538
1539         if (file)
1540                 __trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
1541         else
1542                 trace_dump_stack(STACK_SKIP);
1543 }
1544
1545 static void
1546 stacktrace_count_trigger(struct event_trigger_data *data,
1547                          struct trace_buffer *buffer, void *rec,
1548                          struct ring_buffer_event *event)
1549 {
1550         if (!data->count)
1551                 return;
1552
1553         if (data->count != -1)
1554                 (data->count)--;
1555
1556         stacktrace_trigger(data, buffer, rec, event);
1557 }
1558
1559 static int
1560 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1561 {
1562         return event_trigger_print("stacktrace", m, (void *)data->count,
1563                                    data->filter_str);
1564 }
1565
1566 static struct event_trigger_ops stacktrace_trigger_ops = {
1567         .trigger                = stacktrace_trigger,
1568         .print                  = stacktrace_trigger_print,
1569         .init                   = event_trigger_init,
1570         .free                   = event_trigger_free,
1571 };
1572
1573 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1574         .trigger                = stacktrace_count_trigger,
1575         .print                  = stacktrace_trigger_print,
1576         .init                   = event_trigger_init,
1577         .free                   = event_trigger_free,
1578 };
1579
1580 static struct event_trigger_ops *
1581 stacktrace_get_trigger_ops(char *cmd, char *param)
1582 {
1583         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1584 }
1585
1586 static struct event_command trigger_stacktrace_cmd = {
1587         .name                   = "stacktrace",
1588         .trigger_type           = ETT_STACKTRACE,
1589         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1590         .parse                  = event_trigger_parse,
1591         .reg                    = register_trigger,
1592         .unreg                  = unregister_trigger,
1593         .get_trigger_ops        = stacktrace_get_trigger_ops,
1594         .set_filter             = set_trigger_filter,
1595 };
1596
1597 static __init int register_trigger_stacktrace_cmd(void)
1598 {
1599         int ret;
1600
1601         ret = register_event_command(&trigger_stacktrace_cmd);
1602         WARN_ON(ret < 0);
1603
1604         return ret;
1605 }
1606 #else
1607 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1608 #endif /* CONFIG_STACKTRACE */
1609
1610 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1611 {
1612         unregister_event_command(&trigger_traceon_cmd);
1613         unregister_event_command(&trigger_traceoff_cmd);
1614 }
1615
1616 static void
1617 event_enable_trigger(struct event_trigger_data *data,
1618                      struct trace_buffer *buffer,  void *rec,
1619                      struct ring_buffer_event *event)
1620 {
1621         struct enable_trigger_data *enable_data = data->private_data;
1622
1623         if (enable_data->enable)
1624                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1625         else
1626                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1627 }
1628
1629 static void
1630 event_enable_count_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 (!data->count)
1637                 return;
1638
1639         /* Skip if the event is in a state we want to switch to */
1640         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1641                 return;
1642
1643         if (data->count != -1)
1644                 (data->count)--;
1645
1646         event_enable_trigger(data, buffer, rec, event);
1647 }
1648
1649 int event_enable_trigger_print(struct seq_file *m,
1650                                struct event_trigger_data *data)
1651 {
1652         struct enable_trigger_data *enable_data = data->private_data;
1653
1654         seq_printf(m, "%s:%s:%s",
1655                    enable_data->hist ?
1656                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1657                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1658                    enable_data->file->event_call->class->system,
1659                    trace_event_name(enable_data->file->event_call));
1660
1661         if (data->count == -1)
1662                 seq_puts(m, ":unlimited");
1663         else
1664                 seq_printf(m, ":count=%ld", data->count);
1665
1666         if (data->filter_str)
1667                 seq_printf(m, " if %s\n", data->filter_str);
1668         else
1669                 seq_putc(m, '\n');
1670
1671         return 0;
1672 }
1673
1674 void event_enable_trigger_free(struct event_trigger_data *data)
1675 {
1676         struct enable_trigger_data *enable_data = data->private_data;
1677
1678         if (WARN_ON_ONCE(data->ref <= 0))
1679                 return;
1680
1681         data->ref--;
1682         if (!data->ref) {
1683                 /* Remove the SOFT_MODE flag */
1684                 trace_event_enable_disable(enable_data->file, 0, 1);
1685                 trace_event_put_ref(enable_data->file->event_call);
1686                 trigger_data_free(data);
1687                 kfree(enable_data);
1688         }
1689 }
1690
1691 static struct event_trigger_ops event_enable_trigger_ops = {
1692         .trigger                = event_enable_trigger,
1693         .print                  = event_enable_trigger_print,
1694         .init                   = event_trigger_init,
1695         .free                   = event_enable_trigger_free,
1696 };
1697
1698 static struct event_trigger_ops event_enable_count_trigger_ops = {
1699         .trigger                = event_enable_count_trigger,
1700         .print                  = event_enable_trigger_print,
1701         .init                   = event_trigger_init,
1702         .free                   = event_enable_trigger_free,
1703 };
1704
1705 static struct event_trigger_ops event_disable_trigger_ops = {
1706         .trigger                = event_enable_trigger,
1707         .print                  = event_enable_trigger_print,
1708         .init                   = event_trigger_init,
1709         .free                   = event_enable_trigger_free,
1710 };
1711
1712 static struct event_trigger_ops event_disable_count_trigger_ops = {
1713         .trigger                = event_enable_count_trigger,
1714         .print                  = event_enable_trigger_print,
1715         .init                   = event_trigger_init,
1716         .free                   = event_enable_trigger_free,
1717 };
1718
1719 int event_enable_trigger_parse(struct event_command *cmd_ops,
1720                                struct trace_event_file *file,
1721                                char *glob, char *cmd, char *param_and_filter)
1722 {
1723         struct trace_event_file *event_enable_file;
1724         struct enable_trigger_data *enable_data;
1725         struct event_trigger_data *trigger_data;
1726         struct trace_array *tr = file->tr;
1727         char *param, *filter;
1728         bool enable, remove;
1729         const char *system;
1730         const char *event;
1731         bool hist = false;
1732         int ret;
1733
1734         remove = event_trigger_check_remove(glob);
1735
1736         if (event_trigger_empty_param(param_and_filter))
1737                 return -EINVAL;
1738
1739         ret = event_trigger_separate_filter(param_and_filter, &param, &filter, true);
1740         if (ret)
1741                 return ret;
1742
1743         system = strsep(&param, ":");
1744         if (!param)
1745                 return -EINVAL;
1746
1747         event = strsep(&param, ":");
1748
1749         ret = -EINVAL;
1750         event_enable_file = find_event_file(tr, system, event);
1751         if (!event_enable_file)
1752                 goto out;
1753
1754 #ifdef CONFIG_HIST_TRIGGERS
1755         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1756                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1757
1758         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1759                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1760 #else
1761         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1762 #endif
1763         ret = -ENOMEM;
1764
1765         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1766         if (!enable_data)
1767                 goto out;
1768
1769         enable_data->hist = hist;
1770         enable_data->enable = enable;
1771         enable_data->file = event_enable_file;
1772
1773         trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
1774         if (!trigger_data) {
1775                 kfree(enable_data);
1776                 goto out;
1777         }
1778
1779         if (remove) {
1780                 event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
1781                 kfree(trigger_data);
1782                 kfree(enable_data);
1783                 ret = 0;
1784                 goto out;
1785         }
1786
1787         /* Up the trigger_data count to make sure nothing frees it on failure */
1788         event_trigger_init(trigger_data);
1789
1790         ret = event_trigger_parse_num(param, trigger_data);
1791         if (ret)
1792                 goto out_free;
1793
1794         ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
1795         if (ret < 0)
1796                 goto out_free;
1797
1798         /* Don't let event modules unload while probe registered */
1799         ret = trace_event_try_get_ref(event_enable_file->event_call);
1800         if (!ret) {
1801                 ret = -EBUSY;
1802                 goto out_free;
1803         }
1804
1805         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1806         if (ret < 0)
1807                 goto out_put;
1808
1809         ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
1810         if (ret)
1811                 goto out_disable;
1812
1813         event_trigger_free(trigger_data);
1814  out:
1815         return ret;
1816  out_disable:
1817         trace_event_enable_disable(event_enable_file, 0, 1);
1818  out_put:
1819         trace_event_put_ref(event_enable_file->event_call);
1820  out_free:
1821         event_trigger_reset_filter(cmd_ops, trigger_data);
1822         event_trigger_free(trigger_data);
1823         kfree(enable_data);
1824
1825         goto out;
1826 }
1827
1828 int event_enable_register_trigger(char *glob,
1829                                   struct event_trigger_data *data,
1830                                   struct trace_event_file *file)
1831 {
1832         struct enable_trigger_data *enable_data = data->private_data;
1833         struct enable_trigger_data *test_enable_data;
1834         struct event_trigger_data *test;
1835         int ret = 0;
1836
1837         lockdep_assert_held(&event_mutex);
1838
1839         list_for_each_entry(test, &file->triggers, list) {
1840                 test_enable_data = test->private_data;
1841                 if (test_enable_data &&
1842                     (test->cmd_ops->trigger_type ==
1843                      data->cmd_ops->trigger_type) &&
1844                     (test_enable_data->file == enable_data->file)) {
1845                         ret = -EEXIST;
1846                         goto out;
1847                 }
1848         }
1849
1850         if (data->ops->init) {
1851                 ret = data->ops->init(data);
1852                 if (ret < 0)
1853                         goto out;
1854         }
1855
1856         list_add_rcu(&data->list, &file->triggers);
1857
1858         update_cond_flag(file);
1859         ret = trace_event_trigger_enable_disable(file, 1);
1860         if (ret < 0) {
1861                 list_del_rcu(&data->list);
1862                 update_cond_flag(file);
1863         }
1864 out:
1865         return ret;
1866 }
1867
1868 void event_enable_unregister_trigger(char *glob,
1869                                      struct event_trigger_data *test,
1870                                      struct trace_event_file *file)
1871 {
1872         struct enable_trigger_data *test_enable_data = test->private_data;
1873         struct event_trigger_data *data = NULL, *iter;
1874         struct enable_trigger_data *enable_data;
1875
1876         lockdep_assert_held(&event_mutex);
1877
1878         list_for_each_entry(iter, &file->triggers, list) {
1879                 enable_data = iter->private_data;
1880                 if (enable_data &&
1881                     (iter->cmd_ops->trigger_type ==
1882                      test->cmd_ops->trigger_type) &&
1883                     (enable_data->file == test_enable_data->file)) {
1884                         data = iter;
1885                         list_del_rcu(&data->list);
1886                         trace_event_trigger_enable_disable(file, 0);
1887                         update_cond_flag(file);
1888                         break;
1889                 }
1890         }
1891
1892         if (data && data->ops->free)
1893                 data->ops->free(data);
1894 }
1895
1896 static struct event_trigger_ops *
1897 event_enable_get_trigger_ops(char *cmd, char *param)
1898 {
1899         struct event_trigger_ops *ops;
1900         bool enable;
1901
1902 #ifdef CONFIG_HIST_TRIGGERS
1903         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1904                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1905 #else
1906         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1907 #endif
1908         if (enable)
1909                 ops = param ? &event_enable_count_trigger_ops :
1910                         &event_enable_trigger_ops;
1911         else
1912                 ops = param ? &event_disable_count_trigger_ops :
1913                         &event_disable_trigger_ops;
1914
1915         return ops;
1916 }
1917
1918 static struct event_command trigger_enable_cmd = {
1919         .name                   = ENABLE_EVENT_STR,
1920         .trigger_type           = ETT_EVENT_ENABLE,
1921         .parse                  = event_enable_trigger_parse,
1922         .reg                    = event_enable_register_trigger,
1923         .unreg                  = event_enable_unregister_trigger,
1924         .get_trigger_ops        = event_enable_get_trigger_ops,
1925         .set_filter             = set_trigger_filter,
1926 };
1927
1928 static struct event_command trigger_disable_cmd = {
1929         .name                   = DISABLE_EVENT_STR,
1930         .trigger_type           = ETT_EVENT_ENABLE,
1931         .parse                  = event_enable_trigger_parse,
1932         .reg                    = event_enable_register_trigger,
1933         .unreg                  = event_enable_unregister_trigger,
1934         .get_trigger_ops        = event_enable_get_trigger_ops,
1935         .set_filter             = set_trigger_filter,
1936 };
1937
1938 static __init void unregister_trigger_enable_disable_cmds(void)
1939 {
1940         unregister_event_command(&trigger_enable_cmd);
1941         unregister_event_command(&trigger_disable_cmd);
1942 }
1943
1944 static __init int register_trigger_enable_disable_cmds(void)
1945 {
1946         int ret;
1947
1948         ret = register_event_command(&trigger_enable_cmd);
1949         if (WARN_ON(ret < 0))
1950                 return ret;
1951         ret = register_event_command(&trigger_disable_cmd);
1952         if (WARN_ON(ret < 0))
1953                 unregister_trigger_enable_disable_cmds();
1954
1955         return ret;
1956 }
1957
1958 static __init int register_trigger_traceon_traceoff_cmds(void)
1959 {
1960         int ret;
1961
1962         ret = register_event_command(&trigger_traceon_cmd);
1963         if (WARN_ON(ret < 0))
1964                 return ret;
1965         ret = register_event_command(&trigger_traceoff_cmd);
1966         if (WARN_ON(ret < 0))
1967                 unregister_trigger_traceon_traceoff_cmds();
1968
1969         return ret;
1970 }
1971
1972 __init int register_trigger_cmds(void)
1973 {
1974         register_trigger_traceon_traceoff_cmds();
1975         register_trigger_snapshot_cmd();
1976         register_trigger_stacktrace_cmd();
1977         register_trigger_enable_disable_cmds();
1978         register_trigger_hist_enable_disable_cmds();
1979         register_trigger_hist_cmd();
1980
1981         return 0;
1982 }