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 <[email protected]>
   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->func(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->func(data, buffer, rec, event);
  82         }
  83         return tt;
  84 }
  85 EXPORT_SYMBOL_GPL(event_triggers_call);
  86
  87 /**
  88  * event_triggers_post_call - Call 'post_triggers' for a trace event
  89  * @file: The trace_event_file associated with the event
  90  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
  91  *
  92  * For each trigger associated with an event, invoke the trigger
  93  * function registered with the associated trigger command, if the
  94  * corresponding bit is set in the tt enum passed into this function.
  95  * See @event_triggers_call for details on how those bits are set.
  96  *
  97  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  98  */
  99 void
 100 event_triggers_post_call(struct trace_event_file *file,
 101                          enum event_trigger_type tt)
 102 {
 103         struct event_trigger_data *data;
 104
 105         list_for_each_entry_rcu(data, &file->triggers, list) {
 106                 if (data->paused)
 107                         continue;
 108                 if (data->cmd_ops->trigger_type & tt)
 109                         data->ops->func(data, NULL, NULL, NULL);
 110         }
 111 }
 112 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 113
 114 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 115
 116 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 117 {
 118         struct trace_event_file *event_file = event_file_data(m->private);
 119
 120         if (t == SHOW_AVAILABLE_TRIGGERS) {
 121                 (*pos)++;
 122                 return NULL;
 123         }
 124         return seq_list_next(t, &event_file->triggers, pos);
 125 }
 126
 127 static void *trigger_start(struct seq_file *m, loff_t *pos)
 128 {
 129         struct trace_event_file *event_file;
 130
 131         /* ->stop() is called even if ->start() fails */
 132         mutex_lock(&event_mutex);
 133         event_file = event_file_data(m->private);
 134         if (unlikely(!event_file))
 135                 return ERR_PTR(-ENODEV);
 136
 137         if (list_empty(&event_file->triggers))
 138                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 139
 140         return seq_list_start(&event_file->triggers, *pos);
 141 }
 142
 143 static void trigger_stop(struct seq_file *m, void *t)
 144 {
 145         mutex_unlock(&event_mutex);
 146 }
 147
 148 static int trigger_show(struct seq_file *m, void *v)
 149 {
 150         struct event_trigger_data *data;
 151         struct event_command *p;
 152
 153         if (v == SHOW_AVAILABLE_TRIGGERS) {
 154                 seq_puts(m, "# Available triggers:\n");
 155                 seq_putc(m, '#');
 156                 mutex_lock(&trigger_cmd_mutex);
 157                 list_for_each_entry_reverse(p, &trigger_commands, list)
 158                         seq_printf(m, " %s", p->name);
 159                 seq_putc(m, '\n');
 160                 mutex_unlock(&trigger_cmd_mutex);
 161                 return 0;
 162         }
 163
 164         data = list_entry(v, struct event_trigger_data, list);
 165         data->ops->print(m, data->ops, data);
 166
 167         return 0;
 168 }
 169
 170 static const struct seq_operations event_triggers_seq_ops = {
 171         .start = trigger_start,
 172         .next = trigger_next,
 173         .stop = trigger_stop,
 174         .show = trigger_show,
 175 };
 176
 177 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 178 {
 179         int ret;
 180
 181         ret = security_locked_down(LOCKDOWN_TRACEFS);
 182         if (ret)
 183                 return ret;
 184
 185         mutex_lock(&event_mutex);
 186
 187         if (unlikely(!event_file_data(file))) {
 188                 mutex_unlock(&event_mutex);
 189                 return -ENODEV;
 190         }
 191
 192         if ((file->f_mode & FMODE_WRITE) &&
 193             (file->f_flags & O_TRUNC)) {
 194                 struct trace_event_file *event_file;
 195                 struct event_command *p;
 196
 197                 event_file = event_file_data(file);
 198
 199                 list_for_each_entry(p, &trigger_commands, list) {
 200                         if (p->unreg_all)
 201                                 p->unreg_all(event_file);
 202                 }
 203         }
 204
 205         if (file->f_mode & FMODE_READ) {
 206                 ret = seq_open(file, &event_triggers_seq_ops);
 207                 if (!ret) {
 208                         struct seq_file *m = file->private_data;
 209                         m->private = file;
 210                 }
 211         }
 212
 213         mutex_unlock(&event_mutex);
 214
 215         return ret;
 216 }
 217
 218 int trigger_process_regex(struct trace_event_file *file, char *buff)
 219 {
 220         char *command, *next;
 221         struct event_command *p;
 222         int ret = -EINVAL;
 223
 224         next = buff = skip_spaces(buff);
 225         command = strsep(&next, ": \t");
 226         if (next) {
 227                 next = skip_spaces(next);
 228                 if (!*next)
 229                         next = NULL;
 230         }
 231         command = (command[0] != '!') ? command : command + 1;
 232
 233         mutex_lock(&trigger_cmd_mutex);
 234         list_for_each_entry(p, &trigger_commands, list) {
 235                 if (strcmp(p->name, command) == 0) {
 236                         ret = p->func(p, file, buff, command, next);
 237                         goto out_unlock;
 238                 }
 239         }
 240  out_unlock:
 241         mutex_unlock(&trigger_cmd_mutex);
 242
 243         return ret;
 244 }
 245
 246 static ssize_t event_trigger_regex_write(struct file *file,
 247                                          const char __user *ubuf,
 248                                          size_t cnt, loff_t *ppos)
 249 {
 250         struct trace_event_file *event_file;
 251         ssize_t ret;
 252         char *buf;
 253
 254         if (!cnt)
 255                 return 0;
 256
 257         if (cnt >= PAGE_SIZE)
 258                 return -EINVAL;
 259
 260         buf = memdup_user_nul(ubuf, cnt);
 261         if (IS_ERR(buf))
 262                 return PTR_ERR(buf);
 263
 264         strim(buf);
 265
 266         mutex_lock(&event_mutex);
 267         event_file = event_file_data(file);
 268         if (unlikely(!event_file)) {
 269                 mutex_unlock(&event_mutex);
 270                 kfree(buf);
 271                 return -ENODEV;
 272         }
 273         ret = trigger_process_regex(event_file, buf);
 274         mutex_unlock(&event_mutex);
 275
 276         kfree(buf);
 277         if (ret < 0)
 278                 goto out;
 279
 280         *ppos += cnt;
 281         ret = cnt;
 282  out:
 283         return ret;
 284 }
 285
 286 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 287 {
 288         mutex_lock(&event_mutex);
 289
 290         if (file->f_mode & FMODE_READ)
 291                 seq_release(inode, file);
 292
 293         mutex_unlock(&event_mutex);
 294
 295         return 0;
 296 }
 297
 298 static ssize_t
 299 event_trigger_write(struct file *filp, const char __user *ubuf,
 300                     size_t cnt, loff_t *ppos)
 301 {
 302         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 303 }
 304
 305 static int
 306 event_trigger_open(struct inode *inode, struct file *filp)
 307 {
 308         /* Checks for tracefs lockdown */
 309         return event_trigger_regex_open(inode, filp);
 310 }
 311
 312 static int
 313 event_trigger_release(struct inode *inode, struct file *file)
 314 {
 315         return event_trigger_regex_release(inode, file);
 316 }
 317
 318 const struct file_operations event_trigger_fops = {
 319         .open = event_trigger_open,
 320         .read = seq_read,
 321         .write = event_trigger_write,
 322         .llseek = tracing_lseek,
 323         .release = event_trigger_release,
 324 };
 325
 326 /*
 327  * Currently we only register event commands from __init, so mark this
 328  * __init too.
 329  */
 330 __init int register_event_command(struct event_command *cmd)
 331 {
 332         struct event_command *p;
 333         int ret = 0;
 334
 335         mutex_lock(&trigger_cmd_mutex);
 336         list_for_each_entry(p, &trigger_commands, list) {
 337                 if (strcmp(cmd->name, p->name) == 0) {
 338                         ret = -EBUSY;
 339                         goto out_unlock;
 340                 }
 341         }
 342         list_add(&cmd->list, &trigger_commands);
 343  out_unlock:
 344         mutex_unlock(&trigger_cmd_mutex);
 345
 346         return ret;
 347 }
 348
 349 /*
 350  * Currently we only unregister event commands from __init, so mark
 351  * this __init too.
 352  */
 353 __init int unregister_event_command(struct event_command *cmd)
 354 {
 355         struct event_command *p, *n;
 356         int ret = -ENODEV;
 357
 358         mutex_lock(&trigger_cmd_mutex);
 359         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 360                 if (strcmp(cmd->name, p->name) == 0) {
 361                         ret = 0;
 362                         list_del_init(&p->list);
 363                         goto out_unlock;
 364                 }
 365         }
 366  out_unlock:
 367         mutex_unlock(&trigger_cmd_mutex);
 368
 369         return ret;
 370 }
 371
 372 /**
 373  * event_trigger_print - Generic event_trigger_ops @print implementation
 374  * @name: The name of the event trigger
 375  * @m: The seq_file being printed to
 376  * @data: Trigger-specific data
 377  * @filter_str: filter_str to print, if present
 378  *
 379  * Common implementation for event triggers to print themselves.
 380  *
 381  * Usually wrapped by a function that simply sets the @name of the
 382  * trigger command and then invokes this.
 383  *
 384  * Return: 0 on success, errno otherwise
 385  */
 386 static int
 387 event_trigger_print(const char *name, struct seq_file *m,
 388                     void *data, char *filter_str)
 389 {
 390         long count = (long)data;
 391
 392         seq_puts(m, name);
 393
 394         if (count == -1)
 395                 seq_puts(m, ":unlimited");
 396         else
 397                 seq_printf(m, ":count=%ld", count);
 398
 399         if (filter_str)
 400                 seq_printf(m, " if %s\n", filter_str);
 401         else
 402                 seq_putc(m, '\n');
 403
 404         return 0;
 405 }
 406
 407 /**
 408  * event_trigger_init - Generic event_trigger_ops @init implementation
 409  * @ops: The trigger ops associated with the trigger
 410  * @data: Trigger-specific data
 411  *
 412  * Common implementation of event trigger initialization.
 413  *
 414  * Usually used directly as the @init method in event trigger
 415  * implementations.
 416  *
 417  * Return: 0 on success, errno otherwise
 418  */
 419 int event_trigger_init(struct event_trigger_ops *ops,
 420                        struct event_trigger_data *data)
 421 {
 422         data->ref++;
 423         return 0;
 424 }
 425
 426 /**
 427  * event_trigger_free - Generic event_trigger_ops @free implementation
 428  * @ops: The trigger ops associated with the trigger
 429  * @data: Trigger-specific data
 430  *
 431  * Common implementation of event trigger de-initialization.
 432  *
 433  * Usually used directly as the @free method in event trigger
 434  * implementations.
 435  */
 436 static void
 437 event_trigger_free(struct event_trigger_ops *ops,
 438                    struct event_trigger_data *data)
 439 {
 440         if (WARN_ON_ONCE(data->ref <= 0))
 441                 return;
 442
 443         data->ref--;
 444         if (!data->ref)
 445                 trigger_data_free(data);
 446 }
 447
 448 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 449                                        int trigger_enable)
 450 {
 451         int ret = 0;
 452
 453         if (trigger_enable) {
 454                 if (atomic_inc_return(&file->tm_ref) > 1)
 455                         return ret;
 456                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 457                 ret = trace_event_enable_disable(file, 1, 1);
 458         } else {
 459                 if (atomic_dec_return(&file->tm_ref) > 0)
 460                         return ret;
 461                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 462                 ret = trace_event_enable_disable(file, 0, 1);
 463         }
 464
 465         return ret;
 466 }
 467
 468 /**
 469  * clear_event_triggers - Clear all triggers associated with a trace array
 470  * @tr: The trace array to clear
 471  *
 472  * For each trigger, the triggering event has its tm_ref decremented
 473  * via trace_event_trigger_enable_disable(), and any associated event
 474  * (in the case of enable/disable_event triggers) will have its sm_ref
 475  * decremented via free()->trace_event_enable_disable().  That
 476  * combination effectively reverses the soft-mode/trigger state added
 477  * by trigger registration.
 478  *
 479  * Must be called with event_mutex held.
 480  */
 481 void
 482 clear_event_triggers(struct trace_array *tr)
 483 {
 484         struct trace_event_file *file;
 485
 486         list_for_each_entry(file, &tr->events, list) {
 487                 struct event_trigger_data *data, *n;
 488                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 489                         trace_event_trigger_enable_disable(file, 0);
 490                         list_del_rcu(&data->list);
 491                         if (data->ops->free)
 492                                 data->ops->free(data->ops, data);
 493                 }
 494         }
 495 }
 496
 497 /**
 498  * update_cond_flag - Set or reset the TRIGGER_COND bit
 499  * @file: The trace_event_file associated with the event
 500  *
 501  * If an event has triggers and any of those triggers has a filter or
 502  * a post_trigger, trigger invocation needs to be deferred until after
 503  * the current event has logged its data, and the event should have
 504  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 505  * cleared.
 506  */
 507 void update_cond_flag(struct trace_event_file *file)
 508 {
 509         struct event_trigger_data *data;
 510         bool set_cond = false;
 511
 512         lockdep_assert_held(&event_mutex);
 513
 514         list_for_each_entry(data, &file->triggers, list) {
 515                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 516                     event_command_needs_rec(data->cmd_ops)) {
 517                         set_cond = true;
 518                         break;
 519                 }
 520         }
 521
 522         if (set_cond)
 523                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 524         else
 525                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 526 }
 527
 528 /**
 529  * register_trigger - Generic event_command @reg implementation
 530  * @glob: The raw string used to register the trigger
 531  * @ops: The trigger ops associated with the trigger
 532  * @data: Trigger-specific data to associate with the trigger
 533  * @file: The trace_event_file associated with the event
 534  *
 535  * Common implementation for event trigger registration.
 536  *
 537  * Usually used directly as the @reg method in event command
 538  * implementations.
 539  *
 540  * Return: 0 on success, errno otherwise
 541  */
 542 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 543                             struct event_trigger_data *data,
 544                             struct trace_event_file *file)
 545 {
 546         struct event_trigger_data *test;
 547         int ret = 0;
 548
 549         lockdep_assert_held(&event_mutex);
 550
 551         list_for_each_entry(test, &file->triggers, list) {
 552                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 553                         ret = -EEXIST;
 554                         goto out;
 555                 }
 556         }
 557
 558         if (data->ops->init) {
 559                 ret = data->ops->init(data->ops, data);
 560                 if (ret < 0)
 561                         goto out;
 562         }
 563
 564         list_add_rcu(&data->list, &file->triggers);
 565         ret++;
 566
 567         update_cond_flag(file);
 568         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 569                 list_del_rcu(&data->list);
 570                 update_cond_flag(file);
 571                 ret--;
 572         }
 573 out:
 574         return ret;
 575 }
 576
 577 /**
 578  * unregister_trigger - Generic event_command @unreg implementation
 579  * @glob: The raw string used to register the trigger
 580  * @ops: The trigger ops associated with the trigger
 581  * @test: Trigger-specific data used to find the trigger to remove
 582  * @file: The trace_event_file associated with the event
 583  *
 584  * Common implementation for event trigger unregistration.
 585  *
 586  * Usually used directly as the @unreg method in event command
 587  * implementations.
 588  */
 589 static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 590                                struct event_trigger_data *test,
 591                                struct trace_event_file *file)
 592 {
 593         struct event_trigger_data *data;
 594         bool unregistered = false;
 595
 596         lockdep_assert_held(&event_mutex);
 597
 598         list_for_each_entry(data, &file->triggers, list) {
 599                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 600                         unregistered = true;
 601                         list_del_rcu(&data->list);
 602                         trace_event_trigger_enable_disable(file, 0);
 603                         update_cond_flag(file);
 604                         break;
 605                 }
 606         }
 607
 608         if (unregistered && data->ops->free)
 609                 data->ops->free(data->ops, data);
 610 }
 611
 612 /**
 613  * event_trigger_callback - Generic event_command @func implementation
 614  * @cmd_ops: The command ops, used for trigger registration
 615  * @file: The trace_event_file associated with the event
 616  * @glob: The raw string used to register the trigger
 617  * @cmd: The cmd portion of the string used to register the trigger
 618  * @param: The params portion of the string used to register the trigger
 619  *
 620  * Common implementation for event command parsing and trigger
 621  * instantiation.
 622  *
 623  * Usually used directly as the @func method in event command
 624  * implementations.
 625  *
 626  * Return: 0 on success, errno otherwise
 627  */
 628 static int
 629 event_trigger_callback(struct event_command *cmd_ops,
 630                        struct trace_event_file *file,
 631                        char *glob, char *cmd, char *param)
 632 {
 633         struct event_trigger_data *trigger_data;
 634         struct event_trigger_ops *trigger_ops;
 635         char *trigger = NULL;
 636         char *number;
 637         int ret;
 638
 639         /* separate the trigger from the filter (t:n [if filter]) */
 640         if (param && isdigit(param[0])) {
 641                 trigger = strsep(&param, " \t");
 642                 if (param) {
 643                         param = skip_spaces(param);
 644                         if (!*param)
 645                                 param = NULL;
 646                 }
 647         }
 648
 649         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 650
 651         ret = -ENOMEM;
 652         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 653         if (!trigger_data)
 654                 goto out;
 655
 656         trigger_data->count = -1;
 657         trigger_data->ops = trigger_ops;
 658         trigger_data->cmd_ops = cmd_ops;
 659         trigger_data->private_data = file;
 660         INIT_LIST_HEAD(&trigger_data->list);
 661         INIT_LIST_HEAD(&trigger_data->named_list);
 662
 663         if (glob[0] == '!') {
 664                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 665                 kfree(trigger_data);
 666                 ret = 0;
 667                 goto out;
 668         }
 669
 670         if (trigger) {
 671                 number = strsep(&trigger, ":");
 672
 673                 ret = -EINVAL;
 674                 if (!strlen(number))
 675                         goto out_free;
 676
 677                 /*
 678                  * We use the callback data field (which is a pointer)
 679                  * as our counter.
 680                  */
 681                 ret = kstrtoul(number, 0, &trigger_data->count);
 682                 if (ret)
 683                         goto out_free;
 684         }
 685
 686         if (!param) /* if param is non-empty, it's supposed to be a filter */
 687                 goto out_reg;
 688
 689         if (!cmd_ops->set_filter)
 690                 goto out_reg;
 691
 692         ret = cmd_ops->set_filter(param, trigger_data, file);
 693         if (ret < 0)
 694                 goto out_free;
 695
 696  out_reg:
 697         /* Up the trigger_data count to make sure reg doesn't free it on failure */
 698         event_trigger_init(trigger_ops, trigger_data);
 699         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 700         /*
 701          * The above returns on success the # of functions enabled,
 702          * but if it didn't find any functions it returns zero.
 703          * Consider no functions a failure too.
 704          */
 705         if (!ret) {
 706                 cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 707                 ret = -ENOENT;
 708         } else if (ret > 0)
 709                 ret = 0;
 710
 711         /* Down the counter of trigger_data or free it if not used anymore */
 712         event_trigger_free(trigger_ops, trigger_data);
 713  out:
 714         return ret;
 715
 716  out_free:
 717         if (cmd_ops->set_filter)
 718                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 719         kfree(trigger_data);
 720         goto out;
 721 }
 722
 723 /**
 724  * set_trigger_filter - Generic event_command @set_filter implementation
 725  * @filter_str: The filter string for the trigger, NULL to remove filter
 726  * @trigger_data: Trigger-specific data
 727  * @file: The trace_event_file associated with the event
 728  *
 729  * Common implementation for event command filter parsing and filter
 730  * instantiation.
 731  *
 732  * Usually used directly as the @set_filter method in event command
 733  * implementations.
 734  *
 735  * Also used to remove a filter (if filter_str = NULL).
 736  *
 737  * Return: 0 on success, errno otherwise
 738  */
 739 int set_trigger_filter(char *filter_str,
 740                        struct event_trigger_data *trigger_data,
 741                        struct trace_event_file *file)
 742 {
 743         struct event_trigger_data *data = trigger_data;
 744         struct event_filter *filter = NULL, *tmp;
 745         int ret = -EINVAL;
 746         char *s;
 747
 748         if (!filter_str) /* clear the current filter */
 749                 goto assign;
 750
 751         s = strsep(&filter_str, " \t");
 752
 753         if (!strlen(s) || strcmp(s, "if") != 0)
 754                 goto out;
 755
 756         if (!filter_str)
 757                 goto out;
 758
 759         /* The filter is for the 'trigger' event, not the triggered event */
 760         ret = create_event_filter(file->tr, file->event_call,
 761                                   filter_str, false, &filter);
 762         /*
 763          * If create_event_filter() fails, filter still needs to be freed.
 764          * Which the calling code will do with data->filter.
 765          */
 766  assign:
 767         tmp = rcu_access_pointer(data->filter);
 768
 769         rcu_assign_pointer(data->filter, filter);
 770
 771         if (tmp) {
 772                 /* Make sure the call is done with the filter */
 773                 tracepoint_synchronize_unregister();
 774                 free_event_filter(tmp);
 775         }
 776
 777         kfree(data->filter_str);
 778         data->filter_str = NULL;
 779
 780         if (filter_str) {
 781                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 782                 if (!data->filter_str) {
 783                         free_event_filter(rcu_access_pointer(data->filter));
 784                         data->filter = NULL;
 785                         ret = -ENOMEM;
 786                 }
 787         }
 788  out:
 789         return ret;
 790 }
 791
 792 static LIST_HEAD(named_triggers);
 793
 794 /**
 795  * find_named_trigger - Find the common named trigger associated with @name
 796  * @name: The name of the set of named triggers to find the common data for
 797  *
 798  * Named triggers are sets of triggers that share a common set of
 799  * trigger data.  The first named trigger registered with a given name
 800  * owns the common trigger data that the others subsequently
 801  * registered with the same name will reference.  This function
 802  * returns the common trigger data associated with that first
 803  * registered instance.
 804  *
 805  * Return: the common trigger data for the given named trigger on
 806  * success, NULL otherwise.
 807  */
 808 struct event_trigger_data *find_named_trigger(const char *name)
 809 {
 810         struct event_trigger_data *data;
 811
 812         if (!name)
 813                 return NULL;
 814
 815         list_for_each_entry(data, &named_triggers, named_list) {
 816                 if (data->named_data)
 817                         continue;
 818                 if (strcmp(data->name, name) == 0)
 819                         return data;
 820         }
 821
 822         return NULL;
 823 }
 824
 825 /**
 826  * is_named_trigger - determine if a given trigger is a named trigger
 827  * @test: The trigger data to test
 828  *
 829  * Return: true if 'test' is a named trigger, false otherwise.
 830  */
 831 bool is_named_trigger(struct event_trigger_data *test)
 832 {
 833         struct event_trigger_data *data;
 834
 835         list_for_each_entry(data, &named_triggers, named_list) {
 836                 if (test == data)
 837                         return true;
 838         }
 839
 840         return false;
 841 }
 842
 843 /**
 844  * save_named_trigger - save the trigger in the named trigger list
 845  * @name: The name of the named trigger set
 846  * @data: The trigger data to save
 847  *
 848  * Return: 0 if successful, negative error otherwise.
 849  */
 850 int save_named_trigger(const char *name, struct event_trigger_data *data)
 851 {
 852         data->name = kstrdup(name, GFP_KERNEL);
 853         if (!data->name)
 854                 return -ENOMEM;
 855
 856         list_add(&data->named_list, &named_triggers);
 857
 858         return 0;
 859 }
 860
 861 /**
 862  * del_named_trigger - delete a trigger from the named trigger list
 863  * @data: The trigger data to delete
 864  */
 865 void del_named_trigger(struct event_trigger_data *data)
 866 {
 867         kfree(data->name);
 868         data->name = NULL;
 869
 870         list_del(&data->named_list);
 871 }
 872
 873 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 874 {
 875         struct event_trigger_data *test;
 876
 877         list_for_each_entry(test, &named_triggers, named_list) {
 878                 if (strcmp(test->name, data->name) == 0) {
 879                         if (pause) {
 880                                 test->paused_tmp = test->paused;
 881                                 test->paused = true;
 882                         } else {
 883                                 test->paused = test->paused_tmp;
 884                         }
 885                 }
 886         }
 887 }
 888
 889 /**
 890  * pause_named_trigger - Pause all named triggers with the same name
 891  * @data: The trigger data of a named trigger to pause
 892  *
 893  * Pauses a named trigger along with all other triggers having the
 894  * same name.  Because named triggers share a common set of data,
 895  * pausing only one is meaningless, so pausing one named trigger needs
 896  * to pause all triggers with the same name.
 897  */
 898 void pause_named_trigger(struct event_trigger_data *data)
 899 {
 900         __pause_named_trigger(data, true);
 901 }
 902
 903 /**
 904  * unpause_named_trigger - Un-pause all named triggers with the same name
 905  * @data: The trigger data of a named trigger to unpause
 906  *
 907  * Un-pauses a named trigger along with all other triggers having the
 908  * same name.  Because named triggers share a common set of data,
 909  * unpausing only one is meaningless, so unpausing one named trigger
 910  * needs to unpause all triggers with the same name.
 911  */
 912 void unpause_named_trigger(struct event_trigger_data *data)
 913 {
 914         __pause_named_trigger(data, false);
 915 }
 916
 917 /**
 918  * set_named_trigger_data - Associate common named trigger data
 919  * @data: The trigger data of a named trigger to unpause
 920  *
 921  * Named triggers are sets of triggers that share a common set of
 922  * trigger data.  The first named trigger registered with a given name
 923  * owns the common trigger data that the others subsequently
 924  * registered with the same name will reference.  This function
 925  * associates the common trigger data from the first trigger with the
 926  * given trigger.
 927  */
 928 void set_named_trigger_data(struct event_trigger_data *data,
 929                             struct event_trigger_data *named_data)
 930 {
 931         data->named_data = named_data;
 932 }
 933
 934 struct event_trigger_data *
 935 get_named_trigger_data(struct event_trigger_data *data)
 936 {
 937         return data->named_data;
 938 }
 939
 940 static void
 941 traceon_trigger(struct event_trigger_data *data,
 942                 struct trace_buffer *buffer, void *rec,
 943                 struct ring_buffer_event *event)
 944 {
 945         if (tracing_is_on())
 946                 return;
 947
 948         tracing_on();
 949 }
 950
 951 static void
 952 traceon_count_trigger(struct event_trigger_data *data,
 953                       struct trace_buffer *buffer, void *rec,
 954                       struct ring_buffer_event *event)
 955 {
 956         if (tracing_is_on())
 957                 return;
 958
 959         if (!data->count)
 960                 return;
 961
 962         if (data->count != -1)
 963                 (data->count)--;
 964
 965         tracing_on();
 966 }
 967
 968 static void
 969 traceoff_trigger(struct event_trigger_data *data,
 970                  struct trace_buffer *buffer, void *rec,
 971                  struct ring_buffer_event *event)
 972 {
 973         if (!tracing_is_on())
 974                 return;
 975
 976         tracing_off();
 977 }
 978
 979 static void
 980 traceoff_count_trigger(struct event_trigger_data *data,
 981                        struct trace_buffer *buffer, void *rec,
 982                        struct ring_buffer_event *event)
 983 {
 984         if (!tracing_is_on())
 985                 return;
 986
 987         if (!data->count)
 988                 return;
 989
 990         if (data->count != -1)
 991                 (data->count)--;
 992
 993         tracing_off();
 994 }
 995
 996 static int
 997 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 998                       struct event_trigger_data *data)
 999 {
1000         return event_trigger_print("traceon", m, (void *)data->count,
1001                                    data->filter_str);
1002 }
1003
1004 static int
1005 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1006                        struct event_trigger_data *data)
1007 {
1008         return event_trigger_print("traceoff", m, (void *)data->count,
1009                                    data->filter_str);
1010 }
1011
1012 static struct event_trigger_ops traceon_trigger_ops = {
1013         .func                   = traceon_trigger,
1014         .print                  = traceon_trigger_print,
1015         .init                   = event_trigger_init,
1016         .free                   = event_trigger_free,
1017 };
1018
1019 static struct event_trigger_ops traceon_count_trigger_ops = {
1020         .func                   = traceon_count_trigger,
1021         .print                  = traceon_trigger_print,
1022         .init                   = event_trigger_init,
1023         .free                   = event_trigger_free,
1024 };
1025
1026 static struct event_trigger_ops traceoff_trigger_ops = {
1027         .func                   = traceoff_trigger,
1028         .print                  = traceoff_trigger_print,
1029         .init                   = event_trigger_init,
1030         .free                   = event_trigger_free,
1031 };
1032
1033 static struct event_trigger_ops traceoff_count_trigger_ops = {
1034         .func                   = traceoff_count_trigger,
1035         .print                  = traceoff_trigger_print,
1036         .init                   = event_trigger_init,
1037         .free                   = event_trigger_free,
1038 };
1039
1040 static struct event_trigger_ops *
1041 onoff_get_trigger_ops(char *cmd, char *param)
1042 {
1043         struct event_trigger_ops *ops;
1044
1045         /* we register both traceon and traceoff to this callback */
1046         if (strcmp(cmd, "traceon") == 0)
1047                 ops = param ? &traceon_count_trigger_ops :
1048                         &traceon_trigger_ops;
1049         else
1050                 ops = param ? &traceoff_count_trigger_ops :
1051                         &traceoff_trigger_ops;
1052
1053         return ops;
1054 }
1055
1056 static struct event_command trigger_traceon_cmd = {
1057         .name                   = "traceon",
1058         .trigger_type           = ETT_TRACE_ONOFF,
1059         .func                   = event_trigger_callback,
1060         .reg                    = register_trigger,
1061         .unreg                  = unregister_trigger,
1062         .get_trigger_ops        = onoff_get_trigger_ops,
1063         .set_filter             = set_trigger_filter,
1064 };
1065
1066 static struct event_command trigger_traceoff_cmd = {
1067         .name                   = "traceoff",
1068         .trigger_type           = ETT_TRACE_ONOFF,
1069         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1070         .func                   = event_trigger_callback,
1071         .reg                    = register_trigger,
1072         .unreg                  = unregister_trigger,
1073         .get_trigger_ops        = onoff_get_trigger_ops,
1074         .set_filter             = set_trigger_filter,
1075 };
1076
1077 #ifdef CONFIG_TRACER_SNAPSHOT
1078 static void
1079 snapshot_trigger(struct event_trigger_data *data,
1080                  struct trace_buffer *buffer, void *rec,
1081                  struct ring_buffer_event *event)
1082 {
1083         struct trace_event_file *file = data->private_data;
1084
1085         if (file)
1086                 tracing_snapshot_instance(file->tr);
1087         else
1088                 tracing_snapshot();
1089 }
1090
1091 static void
1092 snapshot_count_trigger(struct event_trigger_data *data,
1093                        struct trace_buffer *buffer, void *rec,
1094                        struct ring_buffer_event *event)
1095 {
1096         if (!data->count)
1097                 return;
1098
1099         if (data->count != -1)
1100                 (data->count)--;
1101
1102         snapshot_trigger(data, buffer, rec, event);
1103 }
1104
1105 static int
1106 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1107                           struct event_trigger_data *data,
1108                           struct trace_event_file *file)
1109 {
1110         if (tracing_alloc_snapshot_instance(file->tr) != 0)
1111                 return 0;
1112
1113         return register_trigger(glob, ops, data, file);
1114 }
1115
1116 static int
1117 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1118                        struct event_trigger_data *data)
1119 {
1120         return event_trigger_print("snapshot", m, (void *)data->count,
1121                                    data->filter_str);
1122 }
1123
1124 static struct event_trigger_ops snapshot_trigger_ops = {
1125         .func                   = snapshot_trigger,
1126         .print                  = snapshot_trigger_print,
1127         .init                   = event_trigger_init,
1128         .free                   = event_trigger_free,
1129 };
1130
1131 static struct event_trigger_ops snapshot_count_trigger_ops = {
1132         .func                   = snapshot_count_trigger,
1133         .print                  = snapshot_trigger_print,
1134         .init                   = event_trigger_init,
1135         .free                   = event_trigger_free,
1136 };
1137
1138 static struct event_trigger_ops *
1139 snapshot_get_trigger_ops(char *cmd, char *param)
1140 {
1141         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1142 }
1143
1144 static struct event_command trigger_snapshot_cmd = {
1145         .name                   = "snapshot",
1146         .trigger_type           = ETT_SNAPSHOT,
1147         .func                   = event_trigger_callback,
1148         .reg                    = register_snapshot_trigger,
1149         .unreg                  = unregister_trigger,
1150         .get_trigger_ops        = snapshot_get_trigger_ops,
1151         .set_filter             = set_trigger_filter,
1152 };
1153
1154 static __init int register_trigger_snapshot_cmd(void)
1155 {
1156         int ret;
1157
1158         ret = register_event_command(&trigger_snapshot_cmd);
1159         WARN_ON(ret < 0);
1160
1161         return ret;
1162 }
1163 #else
1164 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1165 #endif /* CONFIG_TRACER_SNAPSHOT */
1166
1167 #ifdef CONFIG_STACKTRACE
1168 #ifdef CONFIG_UNWINDER_ORC
1169 /* Skip 2:
1170  *   event_triggers_post_call()
1171  *   trace_event_raw_event_xxx()
1172  */
1173 # define STACK_SKIP 2
1174 #else
1175 /*
1176  * Skip 4:
1177  *   stacktrace_trigger()
1178  *   event_triggers_post_call()
1179  *   trace_event_buffer_commit()
1180  *   trace_event_raw_event_xxx()
1181  */
1182 #define STACK_SKIP 4
1183 #endif
1184
1185 static void
1186 stacktrace_trigger(struct event_trigger_data *data,
1187                    struct trace_buffer *buffer,  void *rec,
1188                    struct ring_buffer_event *event)
1189 {
1190         trace_dump_stack(STACK_SKIP);
1191 }
1192
1193 static void
1194 stacktrace_count_trigger(struct event_trigger_data *data,
1195                          struct trace_buffer *buffer, void *rec,
1196                          struct ring_buffer_event *event)
1197 {
1198         if (!data->count)
1199                 return;
1200
1201         if (data->count != -1)
1202                 (data->count)--;
1203
1204         stacktrace_trigger(data, buffer, rec, event);
1205 }
1206
1207 static int
1208 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1209                          struct event_trigger_data *data)
1210 {
1211         return event_trigger_print("stacktrace", m, (void *)data->count,
1212                                    data->filter_str);
1213 }
1214
1215 static struct event_trigger_ops stacktrace_trigger_ops = {
1216         .func                   = stacktrace_trigger,
1217         .print                  = stacktrace_trigger_print,
1218         .init                   = event_trigger_init,
1219         .free                   = event_trigger_free,
1220 };
1221
1222 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1223         .func                   = stacktrace_count_trigger,
1224         .print                  = stacktrace_trigger_print,
1225         .init                   = event_trigger_init,
1226         .free                   = event_trigger_free,
1227 };
1228
1229 static struct event_trigger_ops *
1230 stacktrace_get_trigger_ops(char *cmd, char *param)
1231 {
1232         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1233 }
1234
1235 static struct event_command trigger_stacktrace_cmd = {
1236         .name                   = "stacktrace",
1237         .trigger_type           = ETT_STACKTRACE,
1238         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1239         .func                   = event_trigger_callback,
1240         .reg                    = register_trigger,
1241         .unreg                  = unregister_trigger,
1242         .get_trigger_ops        = stacktrace_get_trigger_ops,
1243         .set_filter             = set_trigger_filter,
1244 };
1245
1246 static __init int register_trigger_stacktrace_cmd(void)
1247 {
1248         int ret;
1249
1250         ret = register_event_command(&trigger_stacktrace_cmd);
1251         WARN_ON(ret < 0);
1252
1253         return ret;
1254 }
1255 #else
1256 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1257 #endif /* CONFIG_STACKTRACE */
1258
1259 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1260 {
1261         unregister_event_command(&trigger_traceon_cmd);
1262         unregister_event_command(&trigger_traceoff_cmd);
1263 }
1264
1265 static void
1266 event_enable_trigger(struct event_trigger_data *data,
1267                      struct trace_buffer *buffer,  void *rec,
1268                      struct ring_buffer_event *event)
1269 {
1270         struct enable_trigger_data *enable_data = data->private_data;
1271
1272         if (enable_data->enable)
1273                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1274         else
1275                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1276 }
1277
1278 static void
1279 event_enable_count_trigger(struct event_trigger_data *data,
1280                            struct trace_buffer *buffer,  void *rec,
1281                            struct ring_buffer_event *event)
1282 {
1283         struct enable_trigger_data *enable_data = data->private_data;
1284
1285         if (!data->count)
1286                 return;
1287
1288         /* Skip if the event is in a state we want to switch to */
1289         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1290                 return;
1291
1292         if (data->count != -1)
1293                 (data->count)--;
1294
1295         event_enable_trigger(data, buffer, rec, event);
1296 }
1297
1298 int event_enable_trigger_print(struct seq_file *m,
1299                                struct event_trigger_ops *ops,
1300                                struct event_trigger_data *data)
1301 {
1302         struct enable_trigger_data *enable_data = data->private_data;
1303
1304         seq_printf(m, "%s:%s:%s",
1305                    enable_data->hist ?
1306                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1307                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1308                    enable_data->file->event_call->class->system,
1309                    trace_event_name(enable_data->file->event_call));
1310
1311         if (data->count == -1)
1312                 seq_puts(m, ":unlimited");
1313         else
1314                 seq_printf(m, ":count=%ld", data->count);
1315
1316         if (data->filter_str)
1317                 seq_printf(m, " if %s\n", data->filter_str);
1318         else
1319                 seq_putc(m, '\n');
1320
1321         return 0;
1322 }
1323
1324 void event_enable_trigger_free(struct event_trigger_ops *ops,
1325                                struct event_trigger_data *data)
1326 {
1327         struct enable_trigger_data *enable_data = data->private_data;
1328
1329         if (WARN_ON_ONCE(data->ref <= 0))
1330                 return;
1331
1332         data->ref--;
1333         if (!data->ref) {
1334                 /* Remove the SOFT_MODE flag */
1335                 trace_event_enable_disable(enable_data->file, 0, 1);
1336                 module_put(enable_data->file->event_call->mod);
1337                 trigger_data_free(data);
1338                 kfree(enable_data);
1339         }
1340 }
1341
1342 static struct event_trigger_ops event_enable_trigger_ops = {
1343         .func                   = event_enable_trigger,
1344         .print                  = event_enable_trigger_print,
1345         .init                   = event_trigger_init,
1346         .free                   = event_enable_trigger_free,
1347 };
1348
1349 static struct event_trigger_ops event_enable_count_trigger_ops = {
1350         .func                   = event_enable_count_trigger,
1351         .print                  = event_enable_trigger_print,
1352         .init                   = event_trigger_init,
1353         .free                   = event_enable_trigger_free,
1354 };
1355
1356 static struct event_trigger_ops event_disable_trigger_ops = {
1357         .func                   = event_enable_trigger,
1358         .print                  = event_enable_trigger_print,
1359         .init                   = event_trigger_init,
1360         .free                   = event_enable_trigger_free,
1361 };
1362
1363 static struct event_trigger_ops event_disable_count_trigger_ops = {
1364         .func                   = event_enable_count_trigger,
1365         .print                  = event_enable_trigger_print,
1366         .init                   = event_trigger_init,
1367         .free                   = event_enable_trigger_free,
1368 };
1369
1370 int event_enable_trigger_func(struct event_command *cmd_ops,
1371                               struct trace_event_file *file,
1372                               char *glob, char *cmd, char *param)
1373 {
1374         struct trace_event_file *event_enable_file;
1375         struct enable_trigger_data *enable_data;
1376         struct event_trigger_data *trigger_data;
1377         struct event_trigger_ops *trigger_ops;
1378         struct trace_array *tr = file->tr;
1379         const char *system;
1380         const char *event;
1381         bool hist = false;
1382         char *trigger;
1383         char *number;
1384         bool enable;
1385         int ret;
1386
1387         if (!param)
1388                 return -EINVAL;
1389
1390         /* separate the trigger from the filter (s:e:n [if filter]) */
1391         trigger = strsep(&param, " \t");
1392         if (!trigger)
1393                 return -EINVAL;
1394         if (param) {
1395                 param = skip_spaces(param);
1396                 if (!*param)
1397                         param = NULL;
1398         }
1399
1400         system = strsep(&trigger, ":");
1401         if (!trigger)
1402                 return -EINVAL;
1403
1404         event = strsep(&trigger, ":");
1405
1406         ret = -EINVAL;
1407         event_enable_file = find_event_file(tr, system, event);
1408         if (!event_enable_file)
1409                 goto out;
1410
1411 #ifdef CONFIG_HIST_TRIGGERS
1412         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1413                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1414
1415         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1416                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1417 #else
1418         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1419 #endif
1420         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1421
1422         ret = -ENOMEM;
1423         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1424         if (!trigger_data)
1425                 goto out;
1426
1427         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1428         if (!enable_data) {
1429                 kfree(trigger_data);
1430                 goto out;
1431         }
1432
1433         trigger_data->count = -1;
1434         trigger_data->ops = trigger_ops;
1435         trigger_data->cmd_ops = cmd_ops;
1436         INIT_LIST_HEAD(&trigger_data->list);
1437         RCU_INIT_POINTER(trigger_data->filter, NULL);
1438
1439         enable_data->hist = hist;
1440         enable_data->enable = enable;
1441         enable_data->file = event_enable_file;
1442         trigger_data->private_data = enable_data;
1443
1444         if (glob[0] == '!') {
1445                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1446                 kfree(trigger_data);
1447                 kfree(enable_data);
1448                 ret = 0;
1449                 goto out;
1450         }
1451
1452         /* Up the trigger_data count to make sure nothing frees it on failure */
1453         event_trigger_init(trigger_ops, trigger_data);
1454
1455         if (trigger) {
1456                 number = strsep(&trigger, ":");
1457
1458                 ret = -EINVAL;
1459                 if (!strlen(number))
1460                         goto out_free;
1461
1462                 /*
1463                  * We use the callback data field (which is a pointer)
1464                  * as our counter.
1465                  */
1466                 ret = kstrtoul(number, 0, &trigger_data->count);
1467                 if (ret)
1468                         goto out_free;
1469         }
1470
1471         if (!param) /* if param is non-empty, it's supposed to be a filter */
1472                 goto out_reg;
1473
1474         if (!cmd_ops->set_filter)
1475                 goto out_reg;
1476
1477         ret = cmd_ops->set_filter(param, trigger_data, file);
1478         if (ret < 0)
1479                 goto out_free;
1480
1481  out_reg:
1482         /* Don't let event modules unload while probe registered */
1483         ret = try_module_get(event_enable_file->event_call->mod);
1484         if (!ret) {
1485                 ret = -EBUSY;
1486                 goto out_free;
1487         }
1488
1489         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1490         if (ret < 0)
1491                 goto out_put;
1492         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1493         /*
1494          * The above returns on success the # of functions enabled,
1495          * but if it didn't find any functions it returns zero.
1496          * Consider no functions a failure too.
1497          */
1498         if (!ret) {
1499                 ret = -ENOENT;
1500                 goto out_disable;
1501         } else if (ret < 0)
1502                 goto out_disable;
1503         /* Just return zero, not the number of enabled functions */
1504         ret = 0;
1505         event_trigger_free(trigger_ops, trigger_data);
1506  out:
1507         return ret;
1508
1509  out_disable:
1510         trace_event_enable_disable(event_enable_file, 0, 1);
1511  out_put:
1512         module_put(event_enable_file->event_call->mod);
1513  out_free:
1514         if (cmd_ops->set_filter)
1515                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1516         event_trigger_free(trigger_ops, trigger_data);
1517         kfree(enable_data);
1518         goto out;
1519 }
1520
1521 int event_enable_register_trigger(char *glob,
1522                                   struct event_trigger_ops *ops,
1523                                   struct event_trigger_data *data,
1524                                   struct trace_event_file *file)
1525 {
1526         struct enable_trigger_data *enable_data = data->private_data;
1527         struct enable_trigger_data *test_enable_data;
1528         struct event_trigger_data *test;
1529         int ret = 0;
1530
1531         lockdep_assert_held(&event_mutex);
1532
1533         list_for_each_entry(test, &file->triggers, list) {
1534                 test_enable_data = test->private_data;
1535                 if (test_enable_data &&
1536                     (test->cmd_ops->trigger_type ==
1537                      data->cmd_ops->trigger_type) &&
1538                     (test_enable_data->file == enable_data->file)) {
1539                         ret = -EEXIST;
1540                         goto out;
1541                 }
1542         }
1543
1544         if (data->ops->init) {
1545                 ret = data->ops->init(data->ops, data);
1546                 if (ret < 0)
1547                         goto out;
1548         }
1549
1550         list_add_rcu(&data->list, &file->triggers);
1551         ret++;
1552
1553         update_cond_flag(file);
1554         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1555                 list_del_rcu(&data->list);
1556                 update_cond_flag(file);
1557                 ret--;
1558         }
1559 out:
1560         return ret;
1561 }
1562
1563 void event_enable_unregister_trigger(char *glob,
1564                                      struct event_trigger_ops *ops,
1565                                      struct event_trigger_data *test,
1566                                      struct trace_event_file *file)
1567 {
1568         struct enable_trigger_data *test_enable_data = test->private_data;
1569         struct enable_trigger_data *enable_data;
1570         struct event_trigger_data *data;
1571         bool unregistered = false;
1572
1573         lockdep_assert_held(&event_mutex);
1574
1575         list_for_each_entry(data, &file->triggers, list) {
1576                 enable_data = data->private_data;
1577                 if (enable_data &&
1578                     (data->cmd_ops->trigger_type ==
1579                      test->cmd_ops->trigger_type) &&
1580                     (enable_data->file == test_enable_data->file)) {
1581                         unregistered = true;
1582                         list_del_rcu(&data->list);
1583                         trace_event_trigger_enable_disable(file, 0);
1584                         update_cond_flag(file);
1585                         break;
1586                 }
1587         }
1588
1589         if (unregistered && data->ops->free)
1590                 data->ops->free(data->ops, data);
1591 }
1592
1593 static struct event_trigger_ops *
1594 event_enable_get_trigger_ops(char *cmd, char *param)
1595 {
1596         struct event_trigger_ops *ops;
1597         bool enable;
1598
1599 #ifdef CONFIG_HIST_TRIGGERS
1600         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1601                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1602 #else
1603         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1604 #endif
1605         if (enable)
1606                 ops = param ? &event_enable_count_trigger_ops :
1607                         &event_enable_trigger_ops;
1608         else
1609                 ops = param ? &event_disable_count_trigger_ops :
1610                         &event_disable_trigger_ops;
1611
1612         return ops;
1613 }
1614
1615 static struct event_command trigger_enable_cmd = {
1616         .name                   = ENABLE_EVENT_STR,
1617         .trigger_type           = ETT_EVENT_ENABLE,
1618         .func                   = event_enable_trigger_func,
1619         .reg                    = event_enable_register_trigger,
1620         .unreg                  = event_enable_unregister_trigger,
1621         .get_trigger_ops        = event_enable_get_trigger_ops,
1622         .set_filter             = set_trigger_filter,
1623 };
1624
1625 static struct event_command trigger_disable_cmd = {
1626         .name                   = DISABLE_EVENT_STR,
1627         .trigger_type           = ETT_EVENT_ENABLE,
1628         .func                   = event_enable_trigger_func,
1629         .reg                    = event_enable_register_trigger,
1630         .unreg                  = event_enable_unregister_trigger,
1631         .get_trigger_ops        = event_enable_get_trigger_ops,
1632         .set_filter             = set_trigger_filter,
1633 };
1634
1635 static __init void unregister_trigger_enable_disable_cmds(void)
1636 {
1637         unregister_event_command(&trigger_enable_cmd);
1638         unregister_event_command(&trigger_disable_cmd);
1639 }
1640
1641 static __init int register_trigger_enable_disable_cmds(void)
1642 {
1643         int ret;
1644
1645         ret = register_event_command(&trigger_enable_cmd);
1646         if (WARN_ON(ret < 0))
1647                 return ret;
1648         ret = register_event_command(&trigger_disable_cmd);
1649         if (WARN_ON(ret < 0))
1650                 unregister_trigger_enable_disable_cmds();
1651
1652         return ret;
1653 }
1654
1655 static __init int register_trigger_traceon_traceoff_cmds(void)
1656 {
1657         int ret;
1658
1659         ret = register_event_command(&trigger_traceon_cmd);
1660         if (WARN_ON(ret < 0))
1661                 return ret;
1662         ret = register_event_command(&trigger_traceoff_cmd);
1663         if (WARN_ON(ret < 0))
1664                 unregister_trigger_traceon_traceoff_cmds();
1665
1666         return ret;
1667 }
1668
1669 __init int register_trigger_cmds(void)
1670 {
1671         register_trigger_traceon_traceoff_cmds();
1672         register_trigger_snapshot_cmd();
1673         register_trigger_stacktrace_cmd();
1674         register_trigger_enable_disable_cmds();
1675         register_trigger_hist_enable_disable_cmds();
1676         register_trigger_hist_cmd();
1677
1678         return 0;
1679 }