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                 if (data->flags & EVENT_TRIGGER_FL_PROBE)
 147                         continue;
 148                 return true;
 149         }
 150         return false;
 151 }
 152
 153 static void *trigger_start(struct seq_file *m, loff_t *pos)
 154 {
 155         struct trace_event_file *event_file;
 156
 157         /* ->stop() is called even if ->start() fails */
 158         mutex_lock(&event_mutex);
 159         event_file = event_file_data(m->private);
 160         if (unlikely(!event_file))
 161                 return ERR_PTR(-ENODEV);
 162
 163         if (list_empty(&event_file->triggers) || !check_user_trigger(event_file))
 164                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 165
 166         return seq_list_start(&event_file->triggers, *pos);
 167 }
 168
 169 static void trigger_stop(struct seq_file *m, void *t)
 170 {
 171         mutex_unlock(&event_mutex);
 172 }
 173
 174 static int trigger_show(struct seq_file *m, void *v)
 175 {
 176         struct event_trigger_data *data;
 177         struct event_command *p;
 178
 179         if (v == SHOW_AVAILABLE_TRIGGERS) {
 180                 seq_puts(m, "# Available triggers:\n");
 181                 seq_putc(m, '#');
 182                 mutex_lock(&trigger_cmd_mutex);
 183                 list_for_each_entry_reverse(p, &trigger_commands, list)
 184                         seq_printf(m, " %s", p->name);
 185                 seq_putc(m, '\n');
 186                 mutex_unlock(&trigger_cmd_mutex);
 187                 return 0;
 188         }
 189
 190         data = list_entry(v, struct event_trigger_data, list);
 191         data->ops->print(m, data->ops, data);
 192
 193         return 0;
 194 }
 195
 196 static const struct seq_operations event_triggers_seq_ops = {
 197         .start = trigger_start,
 198         .next = trigger_next,
 199         .stop = trigger_stop,
 200         .show = trigger_show,
 201 };
 202
 203 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 204 {
 205         int ret;
 206
 207         ret = security_locked_down(LOCKDOWN_TRACEFS);
 208         if (ret)
 209                 return ret;
 210
 211         mutex_lock(&event_mutex);
 212
 213         if (unlikely(!event_file_data(file))) {
 214                 mutex_unlock(&event_mutex);
 215                 return -ENODEV;
 216         }
 217
 218         if ((file->f_mode & FMODE_WRITE) &&
 219             (file->f_flags & O_TRUNC)) {
 220                 struct trace_event_file *event_file;
 221                 struct event_command *p;
 222
 223                 event_file = event_file_data(file);
 224
 225                 list_for_each_entry(p, &trigger_commands, list) {
 226                         if (p->unreg_all)
 227                                 p->unreg_all(event_file);
 228                 }
 229         }
 230
 231         if (file->f_mode & FMODE_READ) {
 232                 ret = seq_open(file, &event_triggers_seq_ops);
 233                 if (!ret) {
 234                         struct seq_file *m = file->private_data;
 235                         m->private = file;
 236                 }
 237         }
 238
 239         mutex_unlock(&event_mutex);
 240
 241         return ret;
 242 }
 243
 244 int trigger_process_regex(struct trace_event_file *file, char *buff)
 245 {
 246         char *command, *next;
 247         struct event_command *p;
 248         int ret = -EINVAL;
 249
 250         next = buff = skip_spaces(buff);
 251         command = strsep(&next, ": \t");
 252         if (next) {
 253                 next = skip_spaces(next);
 254                 if (!*next)
 255                         next = NULL;
 256         }
 257         command = (command[0] != '!') ? command : command + 1;
 258
 259         mutex_lock(&trigger_cmd_mutex);
 260         list_for_each_entry(p, &trigger_commands, list) {
 261                 if (strcmp(p->name, command) == 0) {
 262                         ret = p->parse(p, file, buff, command, next);
 263                         goto out_unlock;
 264                 }
 265         }
 266  out_unlock:
 267         mutex_unlock(&trigger_cmd_mutex);
 268
 269         return ret;
 270 }
 271
 272 static ssize_t event_trigger_regex_write(struct file *file,
 273                                          const char __user *ubuf,
 274                                          size_t cnt, loff_t *ppos)
 275 {
 276         struct trace_event_file *event_file;
 277         ssize_t ret;
 278         char *buf;
 279
 280         if (!cnt)
 281                 return 0;
 282
 283         if (cnt >= PAGE_SIZE)
 284                 return -EINVAL;
 285
 286         buf = memdup_user_nul(ubuf, cnt);
 287         if (IS_ERR(buf))
 288                 return PTR_ERR(buf);
 289
 290         strim(buf);
 291
 292         mutex_lock(&event_mutex);
 293         event_file = event_file_data(file);
 294         if (unlikely(!event_file)) {
 295                 mutex_unlock(&event_mutex);
 296                 kfree(buf);
 297                 return -ENODEV;
 298         }
 299         ret = trigger_process_regex(event_file, buf);
 300         mutex_unlock(&event_mutex);
 301
 302         kfree(buf);
 303         if (ret < 0)
 304                 goto out;
 305
 306         *ppos += cnt;
 307         ret = cnt;
 308  out:
 309         return ret;
 310 }
 311
 312 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 313 {
 314         mutex_lock(&event_mutex);
 315
 316         if (file->f_mode & FMODE_READ)
 317                 seq_release(inode, file);
 318
 319         mutex_unlock(&event_mutex);
 320
 321         return 0;
 322 }
 323
 324 static ssize_t
 325 event_trigger_write(struct file *filp, const char __user *ubuf,
 326                     size_t cnt, loff_t *ppos)
 327 {
 328         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 329 }
 330
 331 static int
 332 event_trigger_open(struct inode *inode, struct file *filp)
 333 {
 334         /* Checks for tracefs lockdown */
 335         return event_trigger_regex_open(inode, filp);
 336 }
 337
 338 static int
 339 event_trigger_release(struct inode *inode, struct file *file)
 340 {
 341         return event_trigger_regex_release(inode, file);
 342 }
 343
 344 const struct file_operations event_trigger_fops = {
 345         .open = event_trigger_open,
 346         .read = seq_read,
 347         .write = event_trigger_write,
 348         .llseek = tracing_lseek,
 349         .release = event_trigger_release,
 350 };
 351
 352 /*
 353  * Currently we only register event commands from __init, so mark this
 354  * __init too.
 355  */
 356 __init int register_event_command(struct event_command *cmd)
 357 {
 358         struct event_command *p;
 359         int ret = 0;
 360
 361         mutex_lock(&trigger_cmd_mutex);
 362         list_for_each_entry(p, &trigger_commands, list) {
 363                 if (strcmp(cmd->name, p->name) == 0) {
 364                         ret = -EBUSY;
 365                         goto out_unlock;
 366                 }
 367         }
 368         list_add(&cmd->list, &trigger_commands);
 369  out_unlock:
 370         mutex_unlock(&trigger_cmd_mutex);
 371
 372         return ret;
 373 }
 374
 375 /*
 376  * Currently we only unregister event commands from __init, so mark
 377  * this __init too.
 378  */
 379 __init int unregister_event_command(struct event_command *cmd)
 380 {
 381         struct event_command *p, *n;
 382         int ret = -ENODEV;
 383
 384         mutex_lock(&trigger_cmd_mutex);
 385         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 386                 if (strcmp(cmd->name, p->name) == 0) {
 387                         ret = 0;
 388                         list_del_init(&p->list);
 389                         goto out_unlock;
 390                 }
 391         }
 392  out_unlock:
 393         mutex_unlock(&trigger_cmd_mutex);
 394
 395         return ret;
 396 }
 397
 398 /**
 399  * event_trigger_print - Generic event_trigger_ops @print implementation
 400  * @name: The name of the event trigger
 401  * @m: The seq_file being printed to
 402  * @data: Trigger-specific data
 403  * @filter_str: filter_str to print, if present
 404  *
 405  * Common implementation for event triggers to print themselves.
 406  *
 407  * Usually wrapped by a function that simply sets the @name of the
 408  * trigger command and then invokes this.
 409  *
 410  * Return: 0 on success, errno otherwise
 411  */
 412 static int
 413 event_trigger_print(const char *name, struct seq_file *m,
 414                     void *data, char *filter_str)
 415 {
 416         long count = (long)data;
 417
 418         seq_puts(m, name);
 419
 420         if (count == -1)
 421                 seq_puts(m, ":unlimited");
 422         else
 423                 seq_printf(m, ":count=%ld", count);
 424
 425         if (filter_str)
 426                 seq_printf(m, " if %s\n", filter_str);
 427         else
 428                 seq_putc(m, '\n');
 429
 430         return 0;
 431 }
 432
 433 /**
 434  * event_trigger_init - Generic event_trigger_ops @init implementation
 435  * @ops: The trigger ops associated with the trigger
 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_ops *ops,
 446                        struct event_trigger_data *data)
 447 {
 448         data->ref++;
 449         return 0;
 450 }
 451
 452 /**
 453  * event_trigger_free - Generic event_trigger_ops @free implementation
 454  * @ops: The trigger ops associated with the trigger
 455  * @data: Trigger-specific data
 456  *
 457  * Common implementation of event trigger de-initialization.
 458  *
 459  * Usually used directly as the @free method in event trigger
 460  * implementations.
 461  */
 462 static void
 463 event_trigger_free(struct event_trigger_ops *ops,
 464                    struct event_trigger_data *data)
 465 {
 466         if (WARN_ON_ONCE(data->ref <= 0))
 467                 return;
 468
 469         data->ref--;
 470         if (!data->ref)
 471                 trigger_data_free(data);
 472 }
 473
 474 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 475                                        int trigger_enable)
 476 {
 477         int ret = 0;
 478
 479         if (trigger_enable) {
 480                 if (atomic_inc_return(&file->tm_ref) > 1)
 481                         return ret;
 482                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 483                 ret = trace_event_enable_disable(file, 1, 1);
 484         } else {
 485                 if (atomic_dec_return(&file->tm_ref) > 0)
 486                         return ret;
 487                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 488                 ret = trace_event_enable_disable(file, 0, 1);
 489         }
 490
 491         return ret;
 492 }
 493
 494 /**
 495  * clear_event_triggers - Clear all triggers associated with a trace array
 496  * @tr: The trace array to clear
 497  *
 498  * For each trigger, the triggering event has its tm_ref decremented
 499  * via trace_event_trigger_enable_disable(), and any associated event
 500  * (in the case of enable/disable_event triggers) will have its sm_ref
 501  * decremented via free()->trace_event_enable_disable().  That
 502  * combination effectively reverses the soft-mode/trigger state added
 503  * by trigger registration.
 504  *
 505  * Must be called with event_mutex held.
 506  */
 507 void
 508 clear_event_triggers(struct trace_array *tr)
 509 {
 510         struct trace_event_file *file;
 511
 512         list_for_each_entry(file, &tr->events, list) {
 513                 struct event_trigger_data *data, *n;
 514                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 515                         trace_event_trigger_enable_disable(file, 0);
 516                         list_del_rcu(&data->list);
 517                         if (data->ops->free)
 518                                 data->ops->free(data->ops, data);
 519                 }
 520         }
 521 }
 522
 523 /**
 524  * update_cond_flag - Set or reset the TRIGGER_COND bit
 525  * @file: The trace_event_file associated with the event
 526  *
 527  * If an event has triggers and any of those triggers has a filter or
 528  * a post_trigger, trigger invocation needs to be deferred until after
 529  * the current event has logged its data, and the event should have
 530  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 531  * cleared.
 532  */
 533 void update_cond_flag(struct trace_event_file *file)
 534 {
 535         struct event_trigger_data *data;
 536         bool set_cond = false;
 537
 538         lockdep_assert_held(&event_mutex);
 539
 540         list_for_each_entry(data, &file->triggers, list) {
 541                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 542                     event_command_needs_rec(data->cmd_ops)) {
 543                         set_cond = true;
 544                         break;
 545                 }
 546         }
 547
 548         if (set_cond)
 549                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 550         else
 551                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 552 }
 553
 554 /**
 555  * register_trigger - Generic event_command @reg implementation
 556  * @glob: The raw string used to register the trigger
 557  * @data: Trigger-specific data to associate with the trigger
 558  * @file: The trace_event_file associated with the event
 559  *
 560  * Common implementation for event trigger registration.
 561  *
 562  * Usually used directly as the @reg method in event command
 563  * implementations.
 564  *
 565  * Return: 0 on success, errno otherwise
 566  */
 567 static int register_trigger(char *glob,
 568                             struct event_trigger_data *data,
 569                             struct trace_event_file *file)
 570 {
 571         struct event_trigger_data *test;
 572         int ret = 0;
 573
 574         lockdep_assert_held(&event_mutex);
 575
 576         list_for_each_entry(test, &file->triggers, list) {
 577                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 578                         ret = -EEXIST;
 579                         goto out;
 580                 }
 581         }
 582
 583         if (data->ops->init) {
 584                 ret = data->ops->init(data->ops, data);
 585                 if (ret < 0)
 586                         goto out;
 587         }
 588
 589         list_add_rcu(&data->list, &file->triggers);
 590         ret++;
 591
 592         update_cond_flag(file);
 593         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 594                 list_del_rcu(&data->list);
 595                 update_cond_flag(file);
 596                 ret--;
 597         }
 598 out:
 599         return ret;
 600 }
 601
 602 /**
 603  * unregister_trigger - Generic event_command @unreg implementation
 604  * @glob: The raw string used to register the trigger
 605  * @test: Trigger-specific data used to find the trigger to remove
 606  * @file: The trace_event_file associated with the event
 607  *
 608  * Common implementation for event trigger unregistration.
 609  *
 610  * Usually used directly as the @unreg method in event command
 611  * implementations.
 612  */
 613 static void unregister_trigger(char *glob,
 614                                struct event_trigger_data *test,
 615                                struct trace_event_file *file)
 616 {
 617         struct event_trigger_data *data;
 618         bool unregistered = false;
 619
 620         lockdep_assert_held(&event_mutex);
 621
 622         list_for_each_entry(data, &file->triggers, list) {
 623                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 624                         unregistered = true;
 625                         list_del_rcu(&data->list);
 626                         trace_event_trigger_enable_disable(file, 0);
 627                         update_cond_flag(file);
 628                         break;
 629                 }
 630         }
 631
 632         if (unregistered && data->ops->free)
 633                 data->ops->free(data->ops, data);
 634 }
 635
 636 /*
 637  * Event trigger parsing helper functions.
 638  *
 639  * These functions help make it easier to write an event trigger
 640  * parsing function i.e. the struct event_command.parse() callback
 641  * function responsible for parsing and registering a trigger command
 642  * written to the 'trigger' file.
 643  *
 644  * A trigger command (or just 'trigger' for short) takes the form:
 645  *   [trigger] [if filter]
 646  *
 647  * The struct event_command.parse() callback (and other struct
 648  * event_command functions) refer to several components of a trigger
 649  * command.  Those same components are referenced by the event trigger
 650  * parsing helper functions defined below.  These components are:
 651  *
 652  *   cmd               - the trigger command name
 653  *   glob              - the trigger command name optionally prefaced with '!'
 654  *   param_and_filter  - text following cmd and ':'
 655  *   param             - text following cmd and ':' and stripped of filter
 656  *   filter            - the optional filter text following (and including) 'if'
 657  *
 658  * To illustrate the use of these componenents, here are some concrete
 659  * examples. For the following triggers:
 660  *
 661  *   echo 'traceon:5 if pid == 0' > trigger
 662  *     - 'traceon' is both cmd and glob
 663  *     - '5 if pid == 0' is the param_and_filter
 664  *     - '5' is the param
 665  *     - 'if pid == 0' is the filter
 666  *
 667  *   echo 'enable_event:sys:event:n' > trigger
 668  *     - 'enable_event' is both cmd and glob
 669  *     - 'sys:event:n' is the param_and_filter
 670  *     - 'sys:event:n' is the param
 671  *     - there is no filter
 672  *
 673  *   echo 'hist:keys=pid if prio > 50' > trigger
 674  *     - 'hist' is both cmd and glob
 675  *     - 'keys=pid if prio > 50' is the param_and_filter
 676  *     - 'keys=pid' is the param
 677  *     - 'if prio > 50' is the filter
 678  *
 679  *   echo '!enable_event:sys:event:n' > trigger
 680  *     - 'enable_event' the cmd
 681  *     - '!enable_event' is the glob
 682  *     - 'sys:event:n' is the param_and_filter
 683  *     - 'sys:event:n' is the param
 684  *     - there is no filter
 685  *
 686  *   echo 'traceoff' > trigger
 687  *     - 'traceoff' is both cmd and glob
 688  *     - there is no param_and_filter
 689  *     - there is no param
 690  *     - there is no filter
 691  *
 692  * There are a few different categories of event trigger covered by
 693  * these helpers:
 694  *
 695  *  - triggers that don't require a parameter e.g. traceon
 696  *  - triggers that do require a parameter e.g. enable_event and hist
 697  *  - triggers that though they may not require a param may support an
 698  *    optional 'n' param (n = number of times the trigger should fire)
 699  *    e.g.: traceon:5 or enable_event:sys:event:n
 700  *  - triggers that do not support an 'n' param e.g. hist
 701  *
 702  * These functions can be used or ignored as necessary - it all
 703  * depends on the complexity of the trigger, and the granularity of
 704  * the functions supported reflects the fact that some implementations
 705  * may need to customize certain aspects of their implementations and
 706  * won't need certain functions.  For instance, the hist trigger
 707  * implementation doesn't use event_trigger_separate_filter() because
 708  * it has special requirements for handling the filter.
 709  */
 710
 711 /**
 712  * event_trigger_check_remove - check whether an event trigger specifies remove
 713  * @glob: The trigger command string, with optional remove(!) operator
 714  *
 715  * The event trigger callback implementations pass in 'glob' as a
 716  * parameter.  This is the command name either with or without a
 717  * remove(!)  operator.  This function simply parses the glob and
 718  * determines whether the command corresponds to a trigger removal or
 719  * a trigger addition.
 720  *
 721  * Return: true if this is a remove command, false otherwise
 722  */
 723 bool event_trigger_check_remove(const char *glob)
 724 {
 725         return (glob && glob[0] == '!') ? true : false;
 726 }
 727
 728 /**
 729  * event_trigger_empty_param - check whether the param is empty
 730  * @param: The trigger param string
 731  *
 732  * The event trigger callback implementations pass in 'param' as a
 733  * parameter.  This corresponds to the string following the command
 734  * name minus the command name.  This function can be called by a
 735  * callback implementation for any command that requires a param; a
 736  * callback that doesn't require a param can ignore it.
 737  *
 738  * Return: true if this is an empty param, false otherwise
 739  */
 740 bool event_trigger_empty_param(const char *param)
 741 {
 742         return !param;
 743 }
 744
 745 /**
 746  * event_trigger_separate_filter - separate an event trigger from a filter
 747  * @param: The param string containing trigger and possibly filter
 748  * @trigger: outparam, will be filled with a pointer to the trigger
 749  * @filter: outparam, will be filled with a pointer to the filter
 750  * @param_required: Specifies whether or not the param string is required
 751  *
 752  * Given a param string of the form '[trigger] [if filter]', this
 753  * function separates the filter from the trigger and returns the
 754  * trigger in *trigger and the filter in *filter.  Either the *trigger
 755  * or the *filter may be set to NULL by this function - if not set to
 756  * NULL, they will contain strings corresponding to the trigger and
 757  * filter.
 758  *
 759  * There are two cases that need to be handled with respect to the
 760  * passed-in param: either the param is required, or it is not
 761  * required.  If @param_required is set, and there's no param, it will
 762  * return -EINVAL.  If @param_required is not set and there's a param
 763  * that starts with a number, that corresponds to the case of a
 764  * trigger with :n (n = number of times the trigger should fire) and
 765  * the parsing continues normally; otherwise the function just returns
 766  * and assumes param just contains a filter and there's nothing else
 767  * to do.
 768  *
 769  * Return: 0 on success, errno otherwise
 770  */
 771 int event_trigger_separate_filter(char *param_and_filter, char **param,
 772                                   char **filter, bool param_required)
 773 {
 774         int ret = 0;
 775
 776         *param = *filter = NULL;
 777
 778         if (!param_and_filter) {
 779                 if (param_required)
 780                         ret = -EINVAL;
 781                 goto out;
 782         }
 783
 784         /*
 785          * Here we check for an optional param. The only legal
 786          * optional param is :n, and if that's the case, continue
 787          * below. Otherwise we assume what's left is a filter and
 788          * return it as the filter string for the caller to deal with.
 789          */
 790         if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
 791                 *filter = param_and_filter;
 792                 goto out;
 793         }
 794
 795         /*
 796          * Separate the param from the filter (param [if filter]).
 797          * Here we have either an optional :n param or a required
 798          * param and an optional filter.
 799          */
 800         *param = strsep(&param_and_filter, " \t");
 801
 802         /*
 803          * Here we have a filter, though it may be empty.
 804          */
 805         if (param_and_filter) {
 806                 *filter = skip_spaces(param_and_filter);
 807                 if (!**filter)
 808                         *filter = NULL;
 809         }
 810 out:
 811         return ret;
 812 }
 813
 814 /**
 815  * event_trigger_alloc - allocate and init event_trigger_data for a trigger
 816  * @cmd_ops: The event_command operations for the trigger
 817  * @cmd: The cmd string
 818  * @param: The param string
 819  * @private_data: User data to associate with the event trigger
 820  *
 821  * Allocate an event_trigger_data instance and initialize it.  The
 822  * @cmd_ops are used along with the @cmd and @param to get the
 823  * trigger_ops to assign to the event_trigger_data.  @private_data can
 824  * also be passed in and associated with the event_trigger_data.
 825  *
 826  * Use event_trigger_free() to free an event_trigger_data object.
 827  *
 828  * Return: The trigger_data object success, NULL otherwise
 829  */
 830 struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
 831                                                char *cmd,
 832                                                char *param,
 833                                                void *private_data)
 834 {
 835         struct event_trigger_data *trigger_data;
 836         struct event_trigger_ops *trigger_ops;
 837
 838         trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
 839
 840         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 841         if (!trigger_data)
 842                 return NULL;
 843
 844         trigger_data->count = -1;
 845         trigger_data->ops = trigger_ops;
 846         trigger_data->cmd_ops = cmd_ops;
 847         trigger_data->private_data = private_data;
 848
 849         INIT_LIST_HEAD(&trigger_data->list);
 850         INIT_LIST_HEAD(&trigger_data->named_list);
 851         RCU_INIT_POINTER(trigger_data->filter, NULL);
 852
 853         return trigger_data;
 854 }
 855
 856 /**
 857  * event_trigger_parse_num - parse and return the number param for a trigger
 858  * @param: The param string
 859  * @trigger_data: The trigger_data for the trigger
 860  *
 861  * Parse the :n (n = number of times the trigger should fire) param
 862  * and set the count variable in the trigger_data to the parsed count.
 863  *
 864  * Return: 0 on success, errno otherwise
 865  */
 866 int event_trigger_parse_num(char *param,
 867                             struct event_trigger_data *trigger_data)
 868 {
 869         char *number;
 870         int ret = 0;
 871
 872         if (param) {
 873                 number = strsep(&param, ":");
 874
 875                 if (!strlen(number))
 876                         return -EINVAL;
 877
 878                 /*
 879                  * We use the callback data field (which is a pointer)
 880                  * as our counter.
 881                  */
 882                 ret = kstrtoul(number, 0, &trigger_data->count);
 883         }
 884
 885         return ret;
 886 }
 887
 888 /**
 889  * event_trigger_set_filter - set an event trigger's filter
 890  * @cmd_ops: The event_command operations for the trigger
 891  * @file: The event file for the trigger's event
 892  * @param: The string containing the filter
 893  * @trigger_data: The trigger_data for the trigger
 894  *
 895  * Set the filter for the trigger.  If the filter is NULL, just return
 896  * without error.
 897  *
 898  * Return: 0 on success, errno otherwise
 899  */
 900 int event_trigger_set_filter(struct event_command *cmd_ops,
 901                              struct trace_event_file *file,
 902                              char *param,
 903                              struct event_trigger_data *trigger_data)
 904 {
 905         if (param && cmd_ops->set_filter)
 906                 return cmd_ops->set_filter(param, trigger_data, file);
 907
 908         return 0;
 909 }
 910
 911 /**
 912  * event_trigger_reset_filter - reset an event trigger's filter
 913  * @cmd_ops: The event_command operations for the trigger
 914  * @trigger_data: The trigger_data for the trigger
 915  *
 916  * Reset the filter for the trigger to no filter.
 917  */
 918 void event_trigger_reset_filter(struct event_command *cmd_ops,
 919                                 struct event_trigger_data *trigger_data)
 920 {
 921         if (cmd_ops->set_filter)
 922                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 923 }
 924
 925 /**
 926  * event_trigger_register - register an event trigger
 927  * @cmd_ops: The event_command operations for the trigger
 928  * @file: The event file for the trigger's event
 929  * @glob: The trigger command string, with optional remove(!) operator
 930  * @cmd: The cmd string
 931  * @param: The param string
 932  * @trigger_data: The trigger_data for the trigger
 933  * @n_registered: optional outparam, the number of triggers registered
 934  *
 935  * Register an event trigger.  The @cmd_ops are used to call the
 936  * cmd_ops->reg() function which actually does the registration. The
 937  * cmd_ops->reg() function returns the number of triggers registered,
 938  * which is assigned to n_registered, if n_registered is non-NULL.
 939  *
 940  * Return: 0 on success, errno otherwise
 941  */
 942 int event_trigger_register(struct event_command *cmd_ops,
 943                            struct trace_event_file *file,
 944                            char *glob,
 945                            char *cmd,
 946                            char *param,
 947                            struct event_trigger_data *trigger_data,
 948                            int *n_registered)
 949 {
 950         int ret;
 951
 952         if (n_registered)
 953                 *n_registered = 0;
 954
 955         ret = cmd_ops->reg(glob, trigger_data, file);
 956         /*
 957          * The above returns on success the # of functions enabled,
 958          * but if it didn't find any functions it returns zero.
 959          * Consider no functions a failure too.
 960          */
 961         if (!ret) {
 962                 cmd_ops->unreg(glob, trigger_data, file);
 963                 ret = -ENOENT;
 964         } else if (ret > 0) {
 965                 if (n_registered)
 966                         *n_registered = ret;
 967                 /* Just return zero, not the number of enabled functions */
 968                 ret = 0;
 969         }
 970
 971         return ret;
 972 }
 973
 974 /*
 975  * End event trigger parsing helper functions.
 976  */
 977
 978 /**
 979  * event_trigger_parse - Generic event_command @parse implementation
 980  * @cmd_ops: The command ops, used for trigger registration
 981  * @file: The trace_event_file associated with the event
 982  * @glob: The raw string used to register the trigger
 983  * @cmd: The cmd portion of the string used to register the trigger
 984  * @param: The params portion of the string used to register the trigger
 985  *
 986  * Common implementation for event command parsing and trigger
 987  * instantiation.
 988  *
 989  * Usually used directly as the @parse method in event command
 990  * implementations.
 991  *
 992  * Return: 0 on success, errno otherwise
 993  */
 994 static int
 995 event_trigger_parse(struct event_command *cmd_ops,
 996                     struct trace_event_file *file,
 997                     char *glob, char *cmd, char *param)
 998 {
 999         struct event_trigger_data *trigger_data;
1000         struct event_trigger_ops *trigger_ops;
1001         char *trigger = NULL;
1002         char *number;
1003         int ret;
1004
1005         /* separate the trigger from the filter (t:n [if filter]) */
1006         if (param && isdigit(param[0])) {
1007                 trigger = strsep(&param, " \t");
1008                 if (param) {
1009                         param = skip_spaces(param);
1010                         if (!*param)
1011                                 param = NULL;
1012                 }
1013         }
1014
1015         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1016
1017         ret = -ENOMEM;
1018         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1019         if (!trigger_data)
1020                 goto out;
1021
1022         trigger_data->count = -1;
1023         trigger_data->ops = trigger_ops;
1024         trigger_data->cmd_ops = cmd_ops;
1025         trigger_data->private_data = file;
1026         INIT_LIST_HEAD(&trigger_data->list);
1027         INIT_LIST_HEAD(&trigger_data->named_list);
1028
1029         if (glob[0] == '!') {
1030                 cmd_ops->unreg(glob+1, trigger_data, file);
1031                 kfree(trigger_data);
1032                 ret = 0;
1033                 goto out;
1034         }
1035
1036         if (trigger) {
1037                 number = strsep(&trigger, ":");
1038
1039                 ret = -EINVAL;
1040                 if (!strlen(number))
1041                         goto out_free;
1042
1043                 /*
1044                  * We use the callback data field (which is a pointer)
1045                  * as our counter.
1046                  */
1047                 ret = kstrtoul(number, 0, &trigger_data->count);
1048                 if (ret)
1049                         goto out_free;
1050         }
1051
1052         if (!param) /* if param is non-empty, it's supposed to be a filter */
1053                 goto out_reg;
1054
1055         if (!cmd_ops->set_filter)
1056                 goto out_reg;
1057
1058         ret = cmd_ops->set_filter(param, trigger_data, file);
1059         if (ret < 0)
1060                 goto out_free;
1061
1062  out_reg:
1063         /* Up the trigger_data count to make sure reg doesn't free it on failure */
1064         event_trigger_init(trigger_ops, trigger_data);
1065         ret = cmd_ops->reg(glob, trigger_data, file);
1066         /*
1067          * The above returns on success the # of functions enabled,
1068          * but if it didn't find any functions it returns zero.
1069          * Consider no functions a failure too.
1070          */
1071         if (!ret) {
1072                 cmd_ops->unreg(glob, trigger_data, file);
1073                 ret = -ENOENT;
1074         } else if (ret > 0)
1075                 ret = 0;
1076
1077         /* Down the counter of trigger_data or free it if not used anymore */
1078         event_trigger_free(trigger_ops, trigger_data);
1079  out:
1080         return ret;
1081
1082  out_free:
1083         if (cmd_ops->set_filter)
1084                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1085         kfree(trigger_data);
1086         goto out;
1087 }
1088
1089 /**
1090  * set_trigger_filter - Generic event_command @set_filter implementation
1091  * @filter_str: The filter string for the trigger, NULL to remove filter
1092  * @trigger_data: Trigger-specific data
1093  * @file: The trace_event_file associated with the event
1094  *
1095  * Common implementation for event command filter parsing and filter
1096  * instantiation.
1097  *
1098  * Usually used directly as the @set_filter method in event command
1099  * implementations.
1100  *
1101  * Also used to remove a filter (if filter_str = NULL).
1102  *
1103  * Return: 0 on success, errno otherwise
1104  */
1105 int set_trigger_filter(char *filter_str,
1106                        struct event_trigger_data *trigger_data,
1107                        struct trace_event_file *file)
1108 {
1109         struct event_trigger_data *data = trigger_data;
1110         struct event_filter *filter = NULL, *tmp;
1111         int ret = -EINVAL;
1112         char *s;
1113
1114         if (!filter_str) /* clear the current filter */
1115                 goto assign;
1116
1117         s = strsep(&filter_str, " \t");
1118
1119         if (!strlen(s) || strcmp(s, "if") != 0)
1120                 goto out;
1121
1122         if (!filter_str)
1123                 goto out;
1124
1125         /* The filter is for the 'trigger' event, not the triggered event */
1126         ret = create_event_filter(file->tr, file->event_call,
1127                                   filter_str, false, &filter);
1128         /*
1129          * If create_event_filter() fails, filter still needs to be freed.
1130          * Which the calling code will do with data->filter.
1131          */
1132  assign:
1133         tmp = rcu_access_pointer(data->filter);
1134
1135         rcu_assign_pointer(data->filter, filter);
1136
1137         if (tmp) {
1138                 /* Make sure the call is done with the filter */
1139                 tracepoint_synchronize_unregister();
1140                 free_event_filter(tmp);
1141         }
1142
1143         kfree(data->filter_str);
1144         data->filter_str = NULL;
1145
1146         if (filter_str) {
1147                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
1148                 if (!data->filter_str) {
1149                         free_event_filter(rcu_access_pointer(data->filter));
1150                         data->filter = NULL;
1151                         ret = -ENOMEM;
1152                 }
1153         }
1154  out:
1155         return ret;
1156 }
1157
1158 static LIST_HEAD(named_triggers);
1159
1160 /**
1161  * find_named_trigger - Find the common named trigger associated with @name
1162  * @name: The name of the set of named triggers to find the common data for
1163  *
1164  * Named triggers are sets of triggers that share a common set of
1165  * trigger data.  The first named trigger registered with a given name
1166  * owns the common trigger data that the others subsequently
1167  * registered with the same name will reference.  This function
1168  * returns the common trigger data associated with that first
1169  * registered instance.
1170  *
1171  * Return: the common trigger data for the given named trigger on
1172  * success, NULL otherwise.
1173  */
1174 struct event_trigger_data *find_named_trigger(const char *name)
1175 {
1176         struct event_trigger_data *data;
1177
1178         if (!name)
1179                 return NULL;
1180
1181         list_for_each_entry(data, &named_triggers, named_list) {
1182                 if (data->named_data)
1183                         continue;
1184                 if (strcmp(data->name, name) == 0)
1185                         return data;
1186         }
1187
1188         return NULL;
1189 }
1190
1191 /**
1192  * is_named_trigger - determine if a given trigger is a named trigger
1193  * @test: The trigger data to test
1194  *
1195  * Return: true if 'test' is a named trigger, false otherwise.
1196  */
1197 bool is_named_trigger(struct event_trigger_data *test)
1198 {
1199         struct event_trigger_data *data;
1200
1201         list_for_each_entry(data, &named_triggers, named_list) {
1202                 if (test == data)
1203                         return true;
1204         }
1205
1206         return false;
1207 }
1208
1209 /**
1210  * save_named_trigger - save the trigger in the named trigger list
1211  * @name: The name of the named trigger set
1212  * @data: The trigger data to save
1213  *
1214  * Return: 0 if successful, negative error otherwise.
1215  */
1216 int save_named_trigger(const char *name, struct event_trigger_data *data)
1217 {
1218         data->name = kstrdup(name, GFP_KERNEL);
1219         if (!data->name)
1220                 return -ENOMEM;
1221
1222         list_add(&data->named_list, &named_triggers);
1223
1224         return 0;
1225 }
1226
1227 /**
1228  * del_named_trigger - delete a trigger from the named trigger list
1229  * @data: The trigger data to delete
1230  */
1231 void del_named_trigger(struct event_trigger_data *data)
1232 {
1233         kfree(data->name);
1234         data->name = NULL;
1235
1236         list_del(&data->named_list);
1237 }
1238
1239 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
1240 {
1241         struct event_trigger_data *test;
1242
1243         list_for_each_entry(test, &named_triggers, named_list) {
1244                 if (strcmp(test->name, data->name) == 0) {
1245                         if (pause) {
1246                                 test->paused_tmp = test->paused;
1247                                 test->paused = true;
1248                         } else {
1249                                 test->paused = test->paused_tmp;
1250                         }
1251                 }
1252         }
1253 }
1254
1255 /**
1256  * pause_named_trigger - Pause all named triggers with the same name
1257  * @data: The trigger data of a named trigger to pause
1258  *
1259  * Pauses a named trigger along with all other triggers having the
1260  * same name.  Because named triggers share a common set of data,
1261  * pausing only one is meaningless, so pausing one named trigger needs
1262  * to pause all triggers with the same name.
1263  */
1264 void pause_named_trigger(struct event_trigger_data *data)
1265 {
1266         __pause_named_trigger(data, true);
1267 }
1268
1269 /**
1270  * unpause_named_trigger - Un-pause all named triggers with the same name
1271  * @data: The trigger data of a named trigger to unpause
1272  *
1273  * Un-pauses a named trigger along with all other triggers having the
1274  * same name.  Because named triggers share a common set of data,
1275  * unpausing only one is meaningless, so unpausing one named trigger
1276  * needs to unpause all triggers with the same name.
1277  */
1278 void unpause_named_trigger(struct event_trigger_data *data)
1279 {
1280         __pause_named_trigger(data, false);
1281 }
1282
1283 /**
1284  * set_named_trigger_data - Associate common named trigger data
1285  * @data: The trigger data to associate
1286  * @named_data: The common named trigger to be associated
1287  *
1288  * Named triggers are sets of triggers that share a common set of
1289  * trigger data.  The first named trigger registered with a given name
1290  * owns the common trigger data that the others subsequently
1291  * registered with the same name will reference.  This function
1292  * associates the common trigger data from the first trigger with the
1293  * given trigger.
1294  */
1295 void set_named_trigger_data(struct event_trigger_data *data,
1296                             struct event_trigger_data *named_data)
1297 {
1298         data->named_data = named_data;
1299 }
1300
1301 struct event_trigger_data *
1302 get_named_trigger_data(struct event_trigger_data *data)
1303 {
1304         return data->named_data;
1305 }
1306
1307 static void
1308 traceon_trigger(struct event_trigger_data *data,
1309                 struct trace_buffer *buffer, void *rec,
1310                 struct ring_buffer_event *event)
1311 {
1312         struct trace_event_file *file = data->private_data;
1313
1314         if (file) {
1315                 if (tracer_tracing_is_on(file->tr))
1316                         return;
1317
1318                 tracer_tracing_on(file->tr);
1319                 return;
1320         }
1321
1322         if (tracing_is_on())
1323                 return;
1324
1325         tracing_on();
1326 }
1327
1328 static void
1329 traceon_count_trigger(struct event_trigger_data *data,
1330                       struct trace_buffer *buffer, void *rec,
1331                       struct ring_buffer_event *event)
1332 {
1333         struct trace_event_file *file = data->private_data;
1334
1335         if (file) {
1336                 if (tracer_tracing_is_on(file->tr))
1337                         return;
1338         } else {
1339                 if (tracing_is_on())
1340                         return;
1341         }
1342
1343         if (!data->count)
1344                 return;
1345
1346         if (data->count != -1)
1347                 (data->count)--;
1348
1349         if (file)
1350                 tracer_tracing_on(file->tr);
1351         else
1352                 tracing_on();
1353 }
1354
1355 static void
1356 traceoff_trigger(struct event_trigger_data *data,
1357                  struct trace_buffer *buffer, void *rec,
1358                  struct ring_buffer_event *event)
1359 {
1360         struct trace_event_file *file = data->private_data;
1361
1362         if (file) {
1363                 if (!tracer_tracing_is_on(file->tr))
1364                         return;
1365
1366                 tracer_tracing_off(file->tr);
1367                 return;
1368         }
1369
1370         if (!tracing_is_on())
1371                 return;
1372
1373         tracing_off();
1374 }
1375
1376 static void
1377 traceoff_count_trigger(struct event_trigger_data *data,
1378                        struct trace_buffer *buffer, void *rec,
1379                        struct ring_buffer_event *event)
1380 {
1381         struct trace_event_file *file = data->private_data;
1382
1383         if (file) {
1384                 if (!tracer_tracing_is_on(file->tr))
1385                         return;
1386         } else {
1387                 if (!tracing_is_on())
1388                         return;
1389         }
1390
1391         if (!data->count)
1392                 return;
1393
1394         if (data->count != -1)
1395                 (data->count)--;
1396
1397         if (file)
1398                 tracer_tracing_off(file->tr);
1399         else
1400                 tracing_off();
1401 }
1402
1403 static int
1404 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1405                       struct event_trigger_data *data)
1406 {
1407         return event_trigger_print("traceon", m, (void *)data->count,
1408                                    data->filter_str);
1409 }
1410
1411 static int
1412 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1413                        struct event_trigger_data *data)
1414 {
1415         return event_trigger_print("traceoff", m, (void *)data->count,
1416                                    data->filter_str);
1417 }
1418
1419 static struct event_trigger_ops traceon_trigger_ops = {
1420         .trigger                = traceon_trigger,
1421         .print                  = traceon_trigger_print,
1422         .init                   = event_trigger_init,
1423         .free                   = event_trigger_free,
1424 };
1425
1426 static struct event_trigger_ops traceon_count_trigger_ops = {
1427         .trigger                = traceon_count_trigger,
1428         .print                  = traceon_trigger_print,
1429         .init                   = event_trigger_init,
1430         .free                   = event_trigger_free,
1431 };
1432
1433 static struct event_trigger_ops traceoff_trigger_ops = {
1434         .trigger                = traceoff_trigger,
1435         .print                  = traceoff_trigger_print,
1436         .init                   = event_trigger_init,
1437         .free                   = event_trigger_free,
1438 };
1439
1440 static struct event_trigger_ops traceoff_count_trigger_ops = {
1441         .trigger                = traceoff_count_trigger,
1442         .print                  = traceoff_trigger_print,
1443         .init                   = event_trigger_init,
1444         .free                   = event_trigger_free,
1445 };
1446
1447 static struct event_trigger_ops *
1448 onoff_get_trigger_ops(char *cmd, char *param)
1449 {
1450         struct event_trigger_ops *ops;
1451
1452         /* we register both traceon and traceoff to this callback */
1453         if (strcmp(cmd, "traceon") == 0)
1454                 ops = param ? &traceon_count_trigger_ops :
1455                         &traceon_trigger_ops;
1456         else
1457                 ops = param ? &traceoff_count_trigger_ops :
1458                         &traceoff_trigger_ops;
1459
1460         return ops;
1461 }
1462
1463 static struct event_command trigger_traceon_cmd = {
1464         .name                   = "traceon",
1465         .trigger_type           = ETT_TRACE_ONOFF,
1466         .parse                  = event_trigger_parse,
1467         .reg                    = register_trigger,
1468         .unreg                  = unregister_trigger,
1469         .get_trigger_ops        = onoff_get_trigger_ops,
1470         .set_filter             = set_trigger_filter,
1471 };
1472
1473 static struct event_command trigger_traceoff_cmd = {
1474         .name                   = "traceoff",
1475         .trigger_type           = ETT_TRACE_ONOFF,
1476         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1477         .parse                  = event_trigger_parse,
1478         .reg                    = register_trigger,
1479         .unreg                  = unregister_trigger,
1480         .get_trigger_ops        = onoff_get_trigger_ops,
1481         .set_filter             = set_trigger_filter,
1482 };
1483
1484 #ifdef CONFIG_TRACER_SNAPSHOT
1485 static void
1486 snapshot_trigger(struct event_trigger_data *data,
1487                  struct trace_buffer *buffer, void *rec,
1488                  struct ring_buffer_event *event)
1489 {
1490         struct trace_event_file *file = data->private_data;
1491
1492         if (file)
1493                 tracing_snapshot_instance(file->tr);
1494         else
1495                 tracing_snapshot();
1496 }
1497
1498 static void
1499 snapshot_count_trigger(struct event_trigger_data *data,
1500                        struct trace_buffer *buffer, void *rec,
1501                        struct ring_buffer_event *event)
1502 {
1503         if (!data->count)
1504                 return;
1505
1506         if (data->count != -1)
1507                 (data->count)--;
1508
1509         snapshot_trigger(data, buffer, rec, event);
1510 }
1511
1512 static int
1513 register_snapshot_trigger(char *glob,
1514                           struct event_trigger_data *data,
1515                           struct trace_event_file *file)
1516 {
1517         if (tracing_alloc_snapshot_instance(file->tr) != 0)
1518                 return 0;
1519
1520         return register_trigger(glob, data, file);
1521 }
1522
1523 static int
1524 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1525                        struct event_trigger_data *data)
1526 {
1527         return event_trigger_print("snapshot", m, (void *)data->count,
1528                                    data->filter_str);
1529 }
1530
1531 static struct event_trigger_ops snapshot_trigger_ops = {
1532         .trigger                = snapshot_trigger,
1533         .print                  = snapshot_trigger_print,
1534         .init                   = event_trigger_init,
1535         .free                   = event_trigger_free,
1536 };
1537
1538 static struct event_trigger_ops snapshot_count_trigger_ops = {
1539         .trigger                = snapshot_count_trigger,
1540         .print                  = snapshot_trigger_print,
1541         .init                   = event_trigger_init,
1542         .free                   = event_trigger_free,
1543 };
1544
1545 static struct event_trigger_ops *
1546 snapshot_get_trigger_ops(char *cmd, char *param)
1547 {
1548         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1549 }
1550
1551 static struct event_command trigger_snapshot_cmd = {
1552         .name                   = "snapshot",
1553         .trigger_type           = ETT_SNAPSHOT,
1554         .parse                  = event_trigger_parse,
1555         .reg                    = register_snapshot_trigger,
1556         .unreg                  = unregister_trigger,
1557         .get_trigger_ops        = snapshot_get_trigger_ops,
1558         .set_filter             = set_trigger_filter,
1559 };
1560
1561 static __init int register_trigger_snapshot_cmd(void)
1562 {
1563         int ret;
1564
1565         ret = register_event_command(&trigger_snapshot_cmd);
1566         WARN_ON(ret < 0);
1567
1568         return ret;
1569 }
1570 #else
1571 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1572 #endif /* CONFIG_TRACER_SNAPSHOT */
1573
1574 #ifdef CONFIG_STACKTRACE
1575 #ifdef CONFIG_UNWINDER_ORC
1576 /* Skip 2:
1577  *   event_triggers_post_call()
1578  *   trace_event_raw_event_xxx()
1579  */
1580 # define STACK_SKIP 2
1581 #else
1582 /*
1583  * Skip 4:
1584  *   stacktrace_trigger()
1585  *   event_triggers_post_call()
1586  *   trace_event_buffer_commit()
1587  *   trace_event_raw_event_xxx()
1588  */
1589 #define STACK_SKIP 4
1590 #endif
1591
1592 static void
1593 stacktrace_trigger(struct event_trigger_data *data,
1594                    struct trace_buffer *buffer,  void *rec,
1595                    struct ring_buffer_event *event)
1596 {
1597         struct trace_event_file *file = data->private_data;
1598
1599         if (file)
1600                 __trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
1601         else
1602                 trace_dump_stack(STACK_SKIP);
1603 }
1604
1605 static void
1606 stacktrace_count_trigger(struct event_trigger_data *data,
1607                          struct trace_buffer *buffer, void *rec,
1608                          struct ring_buffer_event *event)
1609 {
1610         if (!data->count)
1611                 return;
1612
1613         if (data->count != -1)
1614                 (data->count)--;
1615
1616         stacktrace_trigger(data, buffer, rec, event);
1617 }
1618
1619 static int
1620 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1621                          struct event_trigger_data *data)
1622 {
1623         return event_trigger_print("stacktrace", m, (void *)data->count,
1624                                    data->filter_str);
1625 }
1626
1627 static struct event_trigger_ops stacktrace_trigger_ops = {
1628         .trigger                = stacktrace_trigger,
1629         .print                  = stacktrace_trigger_print,
1630         .init                   = event_trigger_init,
1631         .free                   = event_trigger_free,
1632 };
1633
1634 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1635         .trigger                = stacktrace_count_trigger,
1636         .print                  = stacktrace_trigger_print,
1637         .init                   = event_trigger_init,
1638         .free                   = event_trigger_free,
1639 };
1640
1641 static struct event_trigger_ops *
1642 stacktrace_get_trigger_ops(char *cmd, char *param)
1643 {
1644         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1645 }
1646
1647 static struct event_command trigger_stacktrace_cmd = {
1648         .name                   = "stacktrace",
1649         .trigger_type           = ETT_STACKTRACE,
1650         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1651         .parse                  = event_trigger_parse,
1652         .reg                    = register_trigger,
1653         .unreg                  = unregister_trigger,
1654         .get_trigger_ops        = stacktrace_get_trigger_ops,
1655         .set_filter             = set_trigger_filter,
1656 };
1657
1658 static __init int register_trigger_stacktrace_cmd(void)
1659 {
1660         int ret;
1661
1662         ret = register_event_command(&trigger_stacktrace_cmd);
1663         WARN_ON(ret < 0);
1664
1665         return ret;
1666 }
1667 #else
1668 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1669 #endif /* CONFIG_STACKTRACE */
1670
1671 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1672 {
1673         unregister_event_command(&trigger_traceon_cmd);
1674         unregister_event_command(&trigger_traceoff_cmd);
1675 }
1676
1677 static void
1678 event_enable_trigger(struct event_trigger_data *data,
1679                      struct trace_buffer *buffer,  void *rec,
1680                      struct ring_buffer_event *event)
1681 {
1682         struct enable_trigger_data *enable_data = data->private_data;
1683
1684         if (enable_data->enable)
1685                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1686         else
1687                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1688 }
1689
1690 static void
1691 event_enable_count_trigger(struct event_trigger_data *data,
1692                            struct trace_buffer *buffer,  void *rec,
1693                            struct ring_buffer_event *event)
1694 {
1695         struct enable_trigger_data *enable_data = data->private_data;
1696
1697         if (!data->count)
1698                 return;
1699
1700         /* Skip if the event is in a state we want to switch to */
1701         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1702                 return;
1703
1704         if (data->count != -1)
1705                 (data->count)--;
1706
1707         event_enable_trigger(data, buffer, rec, event);
1708 }
1709
1710 int event_enable_trigger_print(struct seq_file *m,
1711                                struct event_trigger_ops *ops,
1712                                struct event_trigger_data *data)
1713 {
1714         struct enable_trigger_data *enable_data = data->private_data;
1715
1716         seq_printf(m, "%s:%s:%s",
1717                    enable_data->hist ?
1718                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1719                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1720                    enable_data->file->event_call->class->system,
1721                    trace_event_name(enable_data->file->event_call));
1722
1723         if (data->count == -1)
1724                 seq_puts(m, ":unlimited");
1725         else
1726                 seq_printf(m, ":count=%ld", data->count);
1727
1728         if (data->filter_str)
1729                 seq_printf(m, " if %s\n", data->filter_str);
1730         else
1731                 seq_putc(m, '\n');
1732
1733         return 0;
1734 }
1735
1736 void event_enable_trigger_free(struct event_trigger_ops *ops,
1737                                struct event_trigger_data *data)
1738 {
1739         struct enable_trigger_data *enable_data = data->private_data;
1740
1741         if (WARN_ON_ONCE(data->ref <= 0))
1742                 return;
1743
1744         data->ref--;
1745         if (!data->ref) {
1746                 /* Remove the SOFT_MODE flag */
1747                 trace_event_enable_disable(enable_data->file, 0, 1);
1748                 trace_event_put_ref(enable_data->file->event_call);
1749                 trigger_data_free(data);
1750                 kfree(enable_data);
1751         }
1752 }
1753
1754 static struct event_trigger_ops event_enable_trigger_ops = {
1755         .trigger                = event_enable_trigger,
1756         .print                  = event_enable_trigger_print,
1757         .init                   = event_trigger_init,
1758         .free                   = event_enable_trigger_free,
1759 };
1760
1761 static struct event_trigger_ops event_enable_count_trigger_ops = {
1762         .trigger                = event_enable_count_trigger,
1763         .print                  = event_enable_trigger_print,
1764         .init                   = event_trigger_init,
1765         .free                   = event_enable_trigger_free,
1766 };
1767
1768 static struct event_trigger_ops event_disable_trigger_ops = {
1769         .trigger                = event_enable_trigger,
1770         .print                  = event_enable_trigger_print,
1771         .init                   = event_trigger_init,
1772         .free                   = event_enable_trigger_free,
1773 };
1774
1775 static struct event_trigger_ops event_disable_count_trigger_ops = {
1776         .trigger                = event_enable_count_trigger,
1777         .print                  = event_enable_trigger_print,
1778         .init                   = event_trigger_init,
1779         .free                   = event_enable_trigger_free,
1780 };
1781
1782 int event_enable_trigger_parse(struct event_command *cmd_ops,
1783                                struct trace_event_file *file,
1784                                char *glob, char *cmd, char *param)
1785 {
1786         struct trace_event_file *event_enable_file;
1787         struct enable_trigger_data *enable_data;
1788         struct event_trigger_data *trigger_data;
1789         struct event_trigger_ops *trigger_ops;
1790         struct trace_array *tr = file->tr;
1791         const char *system;
1792         const char *event;
1793         bool hist = false;
1794         char *trigger;
1795         char *number;
1796         bool enable;
1797         int ret;
1798
1799         if (!param)
1800                 return -EINVAL;
1801
1802         /* separate the trigger from the filter (s:e:n [if filter]) */
1803         trigger = strsep(&param, " \t");
1804         if (!trigger)
1805                 return -EINVAL;
1806         if (param) {
1807                 param = skip_spaces(param);
1808                 if (!*param)
1809                         param = NULL;
1810         }
1811
1812         system = strsep(&trigger, ":");
1813         if (!trigger)
1814                 return -EINVAL;
1815
1816         event = strsep(&trigger, ":");
1817
1818         ret = -EINVAL;
1819         event_enable_file = find_event_file(tr, system, event);
1820         if (!event_enable_file)
1821                 goto out;
1822
1823 #ifdef CONFIG_HIST_TRIGGERS
1824         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1825                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1826
1827         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1828                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1829 #else
1830         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1831 #endif
1832         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1833
1834         ret = -ENOMEM;
1835         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1836         if (!trigger_data)
1837                 goto out;
1838
1839         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1840         if (!enable_data) {
1841                 kfree(trigger_data);
1842                 goto out;
1843         }
1844
1845         trigger_data->count = -1;
1846         trigger_data->ops = trigger_ops;
1847         trigger_data->cmd_ops = cmd_ops;
1848         INIT_LIST_HEAD(&trigger_data->list);
1849         RCU_INIT_POINTER(trigger_data->filter, NULL);
1850
1851         enable_data->hist = hist;
1852         enable_data->enable = enable;
1853         enable_data->file = event_enable_file;
1854         trigger_data->private_data = enable_data;
1855
1856         if (glob[0] == '!') {
1857                 cmd_ops->unreg(glob+1, trigger_data, file);
1858                 kfree(trigger_data);
1859                 kfree(enable_data);
1860                 ret = 0;
1861                 goto out;
1862         }
1863
1864         /* Up the trigger_data count to make sure nothing frees it on failure */
1865         event_trigger_init(trigger_ops, trigger_data);
1866
1867         if (trigger) {
1868                 number = strsep(&trigger, ":");
1869
1870                 ret = -EINVAL;
1871                 if (!strlen(number))
1872                         goto out_free;
1873
1874                 /*
1875                  * We use the callback data field (which is a pointer)
1876                  * as our counter.
1877                  */
1878                 ret = kstrtoul(number, 0, &trigger_data->count);
1879                 if (ret)
1880                         goto out_free;
1881         }
1882
1883         if (!param) /* if param is non-empty, it's supposed to be a filter */
1884                 goto out_reg;
1885
1886         if (!cmd_ops->set_filter)
1887                 goto out_reg;
1888
1889         ret = cmd_ops->set_filter(param, trigger_data, file);
1890         if (ret < 0)
1891                 goto out_free;
1892
1893  out_reg:
1894         /* Don't let event modules unload while probe registered */
1895         ret = trace_event_try_get_ref(event_enable_file->event_call);
1896         if (!ret) {
1897                 ret = -EBUSY;
1898                 goto out_free;
1899         }
1900
1901         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1902         if (ret < 0)
1903                 goto out_put;
1904         ret = cmd_ops->reg(glob, trigger_data, file);
1905         /*
1906          * The above returns on success the # of functions enabled,
1907          * but if it didn't find any functions it returns zero.
1908          * Consider no functions a failure too.
1909          */
1910         if (!ret) {
1911                 ret = -ENOENT;
1912                 goto out_disable;
1913         } else if (ret < 0)
1914                 goto out_disable;
1915         /* Just return zero, not the number of enabled functions */
1916         ret = 0;
1917         event_trigger_free(trigger_ops, trigger_data);
1918  out:
1919         return ret;
1920
1921  out_disable:
1922         trace_event_enable_disable(event_enable_file, 0, 1);
1923  out_put:
1924         trace_event_put_ref(event_enable_file->event_call);
1925  out_free:
1926         if (cmd_ops->set_filter)
1927                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1928         event_trigger_free(trigger_ops, trigger_data);
1929         kfree(enable_data);
1930         goto out;
1931 }
1932
1933 int event_enable_register_trigger(char *glob,
1934                                   struct event_trigger_data *data,
1935                                   struct trace_event_file *file)
1936 {
1937         struct enable_trigger_data *enable_data = data->private_data;
1938         struct enable_trigger_data *test_enable_data;
1939         struct event_trigger_data *test;
1940         int ret = 0;
1941
1942         lockdep_assert_held(&event_mutex);
1943
1944         list_for_each_entry(test, &file->triggers, list) {
1945                 test_enable_data = test->private_data;
1946                 if (test_enable_data &&
1947                     (test->cmd_ops->trigger_type ==
1948                      data->cmd_ops->trigger_type) &&
1949                     (test_enable_data->file == enable_data->file)) {
1950                         ret = -EEXIST;
1951                         goto out;
1952                 }
1953         }
1954
1955         if (data->ops->init) {
1956                 ret = data->ops->init(data->ops, data);
1957                 if (ret < 0)
1958                         goto out;
1959         }
1960
1961         list_add_rcu(&data->list, &file->triggers);
1962         ret++;
1963
1964         update_cond_flag(file);
1965         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1966                 list_del_rcu(&data->list);
1967                 update_cond_flag(file);
1968                 ret--;
1969         }
1970 out:
1971         return ret;
1972 }
1973
1974 void event_enable_unregister_trigger(char *glob,
1975                                      struct event_trigger_data *test,
1976                                      struct trace_event_file *file)
1977 {
1978         struct enable_trigger_data *test_enable_data = test->private_data;
1979         struct enable_trigger_data *enable_data;
1980         struct event_trigger_data *data;
1981         bool unregistered = false;
1982
1983         lockdep_assert_held(&event_mutex);
1984
1985         list_for_each_entry(data, &file->triggers, list) {
1986                 enable_data = data->private_data;
1987                 if (enable_data &&
1988                     (data->cmd_ops->trigger_type ==
1989                      test->cmd_ops->trigger_type) &&
1990                     (enable_data->file == test_enable_data->file)) {
1991                         unregistered = true;
1992                         list_del_rcu(&data->list);
1993                         trace_event_trigger_enable_disable(file, 0);
1994                         update_cond_flag(file);
1995                         break;
1996                 }
1997         }
1998
1999         if (unregistered && data->ops->free)
2000                 data->ops->free(data->ops, data);
2001 }
2002
2003 static struct event_trigger_ops *
2004 event_enable_get_trigger_ops(char *cmd, char *param)
2005 {
2006         struct event_trigger_ops *ops;
2007         bool enable;
2008
2009 #ifdef CONFIG_HIST_TRIGGERS
2010         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
2011                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
2012 #else
2013         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2014 #endif
2015         if (enable)
2016                 ops = param ? &event_enable_count_trigger_ops :
2017                         &event_enable_trigger_ops;
2018         else
2019                 ops = param ? &event_disable_count_trigger_ops :
2020                         &event_disable_trigger_ops;
2021
2022         return ops;
2023 }
2024
2025 static struct event_command trigger_enable_cmd = {
2026         .name                   = ENABLE_EVENT_STR,
2027         .trigger_type           = ETT_EVENT_ENABLE,
2028         .parse                  = event_enable_trigger_parse,
2029         .reg                    = event_enable_register_trigger,
2030         .unreg                  = event_enable_unregister_trigger,
2031         .get_trigger_ops        = event_enable_get_trigger_ops,
2032         .set_filter             = set_trigger_filter,
2033 };
2034
2035 static struct event_command trigger_disable_cmd = {
2036         .name                   = DISABLE_EVENT_STR,
2037         .trigger_type           = ETT_EVENT_ENABLE,
2038         .parse                  = event_enable_trigger_parse,
2039         .reg                    = event_enable_register_trigger,
2040         .unreg                  = event_enable_unregister_trigger,
2041         .get_trigger_ops        = event_enable_get_trigger_ops,
2042         .set_filter             = set_trigger_filter,
2043 };
2044
2045 static __init void unregister_trigger_enable_disable_cmds(void)
2046 {
2047         unregister_event_command(&trigger_enable_cmd);
2048         unregister_event_command(&trigger_disable_cmd);
2049 }
2050
2051 static __init int register_trigger_enable_disable_cmds(void)
2052 {
2053         int ret;
2054
2055         ret = register_event_command(&trigger_enable_cmd);
2056         if (WARN_ON(ret < 0))
2057                 return ret;
2058         ret = register_event_command(&trigger_disable_cmd);
2059         if (WARN_ON(ret < 0))
2060                 unregister_trigger_enable_disable_cmds();
2061
2062         return ret;
2063 }
2064
2065 static __init int register_trigger_traceon_traceoff_cmds(void)
2066 {
2067         int ret;
2068
2069         ret = register_event_command(&trigger_traceon_cmd);
2070         if (WARN_ON(ret < 0))
2071                 return ret;
2072         ret = register_event_command(&trigger_traceoff_cmd);
2073         if (WARN_ON(ret < 0))
2074                 unregister_trigger_traceon_traceoff_cmds();
2075
2076         return ret;
2077 }
2078
2079 __init int register_trigger_cmds(void)
2080 {
2081         register_trigger_traceon_traceoff_cmds();
2082         register_trigger_snapshot_cmd();
2083         register_trigger_stacktrace_cmd();
2084         register_trigger_enable_disable_cmds();
2085         register_trigger_hist_enable_disable_cmds();
2086         register_trigger_hist_cmd();
2087
2088         return 0;
2089 }