kernel/trace/trace_events_trigger.c

   1 /*
   2  * trace_events_trigger - trace event triggers
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright (C) 2013 Tom Zanussi <[email protected]>
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/ctype.h>
  23 #include <linux/mutex.h>
  24 #include <linux/slab.h>
  25
  26 #include "trace.h"
  27
  28 static LIST_HEAD(trigger_commands);
  29 static DEFINE_MUTEX(trigger_cmd_mutex);
  30
  31 static void
  32 trigger_data_free(struct event_trigger_data *data)
  33 {
  34         if (data->cmd_ops->set_filter)
  35                 data->cmd_ops->set_filter(NULL, data, NULL);
  36
  37         synchronize_sched(); /* make sure current triggers exit before free */
  38         kfree(data);
  39 }
  40
  41 /**
  42  * event_triggers_call - Call triggers associated with a trace event
  43  * @file: The trace_event_file associated with the event
  44  * @rec: The trace entry for the event, NULL for unconditional invocation
  45  *
  46  * For each trigger associated with an event, invoke the trigger
  47  * function registered with the associated trigger command.  If rec is
  48  * non-NULL, it means that the trigger requires further processing and
  49  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
  50  * trigger has a filter associated with it, rec will checked against
  51  * the filter and if the record matches the trigger will be invoked.
  52  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
  53  * in any case until the current event is written, the trigger
  54  * function isn't invoked but the bit associated with the deferred
  55  * trigger is set in the return value.
  56  *
  57  * Returns an enum event_trigger_type value containing a set bit for
  58  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  59  *
  60  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  61  *
  62  * Return: an enum event_trigger_type value containing a set bit for
  63  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  64  */
  65 enum event_trigger_type
  66 event_triggers_call(struct trace_event_file *file, void *rec)
  67 {
  68         struct event_trigger_data *data;
  69         enum event_trigger_type tt = ETT_NONE;
  70         struct event_filter *filter;
  71
  72         if (list_empty(&file->triggers))
  73                 return tt;
  74
  75         list_for_each_entry_rcu(data, &file->triggers, list) {
  76                 if (!rec) {
  77                         data->ops->func(data);
  78                         continue;
  79                 }
  80                 filter = rcu_dereference_sched(data->filter);
  81                 if (filter && !filter_match_preds(filter, rec))
  82                         continue;
  83                 if (data->cmd_ops->post_trigger) {
  84                         tt |= data->cmd_ops->trigger_type;
  85                         continue;
  86                 }
  87                 data->ops->func(data);
  88         }
  89         return tt;
  90 }
  91 EXPORT_SYMBOL_GPL(event_triggers_call);
  92
  93 /**
  94  * event_triggers_post_call - Call 'post_triggers' for a trace event
  95  * @file: The trace_event_file associated with the event
  96  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
  97  *
  98  * For each trigger associated with an event, invoke the trigger
  99  * function registered with the associated trigger command, if the
 100  * corresponding bit is set in the tt enum passed into this function.
 101  * See @event_triggers_call for details on how those bits are set.
 102  *
 103  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 104  */
 105 void
 106 event_triggers_post_call(struct trace_event_file *file,
 107                          enum event_trigger_type tt)
 108 {
 109         struct event_trigger_data *data;
 110
 111         list_for_each_entry_rcu(data, &file->triggers, list) {
 112                 if (data->cmd_ops->trigger_type & tt)
 113                         data->ops->func(data);
 114         }
 115 }
 116 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 117
 118 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 119
 120 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 121 {
 122         struct trace_event_file *event_file = event_file_data(m->private);
 123
 124         if (t == SHOW_AVAILABLE_TRIGGERS)
 125                 return NULL;
 126
 127         return seq_list_next(t, &event_file->triggers, pos);
 128 }
 129
 130 static void *trigger_start(struct seq_file *m, loff_t *pos)
 131 {
 132         struct trace_event_file *event_file;
 133
 134         /* ->stop() is called even if ->start() fails */
 135         mutex_lock(&event_mutex);
 136         event_file = event_file_data(m->private);
 137         if (unlikely(!event_file))
 138                 return ERR_PTR(-ENODEV);
 139
 140         if (list_empty(&event_file->triggers))
 141                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 142
 143         return seq_list_start(&event_file->triggers, *pos);
 144 }
 145
 146 static void trigger_stop(struct seq_file *m, void *t)
 147 {
 148         mutex_unlock(&event_mutex);
 149 }
 150
 151 static int trigger_show(struct seq_file *m, void *v)
 152 {
 153         struct event_trigger_data *data;
 154         struct event_command *p;
 155
 156         if (v == SHOW_AVAILABLE_TRIGGERS) {
 157                 seq_puts(m, "# Available triggers:\n");
 158                 seq_putc(m, '#');
 159                 mutex_lock(&trigger_cmd_mutex);
 160                 list_for_each_entry_reverse(p, &trigger_commands, list)
 161                         seq_printf(m, " %s", p->name);
 162                 seq_putc(m, '\n');
 163                 mutex_unlock(&trigger_cmd_mutex);
 164                 return 0;
 165         }
 166
 167         data = list_entry(v, struct event_trigger_data, list);
 168         data->ops->print(m, data->ops, data);
 169
 170         return 0;
 171 }
 172
 173 static const struct seq_operations event_triggers_seq_ops = {
 174         .start = trigger_start,
 175         .next = trigger_next,
 176         .stop = trigger_stop,
 177         .show = trigger_show,
 178 };
 179
 180 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 181 {
 182         int ret = 0;
 183
 184         mutex_lock(&event_mutex);
 185
 186         if (unlikely(!event_file_data(file))) {
 187                 mutex_unlock(&event_mutex);
 188                 return -ENODEV;
 189         }
 190
 191         if (file->f_mode & FMODE_READ) {
 192                 ret = seq_open(file, &event_triggers_seq_ops);
 193                 if (!ret) {
 194                         struct seq_file *m = file->private_data;
 195                         m->private = file;
 196                 }
 197         }
 198
 199         mutex_unlock(&event_mutex);
 200
 201         return ret;
 202 }
 203
 204 static int trigger_process_regex(struct trace_event_file *file, char *buff)
 205 {
 206         char *command, *next = buff;
 207         struct event_command *p;
 208         int ret = -EINVAL;
 209
 210         command = strsep(&next, ": \t");
 211         command = (command[0] != '!') ? command : command + 1;
 212
 213         mutex_lock(&trigger_cmd_mutex);
 214         list_for_each_entry(p, &trigger_commands, list) {
 215                 if (strcmp(p->name, command) == 0) {
 216                         ret = p->func(p, file, buff, command, next);
 217                         goto out_unlock;
 218                 }
 219         }
 220  out_unlock:
 221         mutex_unlock(&trigger_cmd_mutex);
 222
 223         return ret;
 224 }
 225
 226 static ssize_t event_trigger_regex_write(struct file *file,
 227                                          const char __user *ubuf,
 228                                          size_t cnt, loff_t *ppos)
 229 {
 230         struct trace_event_file *event_file;
 231         ssize_t ret;
 232         char *buf;
 233
 234         if (!cnt)
 235                 return 0;
 236
 237         if (cnt >= PAGE_SIZE)
 238                 return -EINVAL;
 239
 240         buf = memdup_user_nul(ubuf, cnt);
 241         if (IS_ERR(buf))
 242                 return PTR_ERR(buf);
 243
 244         strim(buf);
 245
 246         mutex_lock(&event_mutex);
 247         event_file = event_file_data(file);
 248         if (unlikely(!event_file)) {
 249                 mutex_unlock(&event_mutex);
 250                 kfree(buf);
 251                 return -ENODEV;
 252         }
 253         ret = trigger_process_regex(event_file, buf);
 254         mutex_unlock(&event_mutex);
 255
 256         kfree(buf);
 257         if (ret < 0)
 258                 goto out;
 259
 260         *ppos += cnt;
 261         ret = cnt;
 262  out:
 263         return ret;
 264 }
 265
 266 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 267 {
 268         mutex_lock(&event_mutex);
 269
 270         if (file->f_mode & FMODE_READ)
 271                 seq_release(inode, file);
 272
 273         mutex_unlock(&event_mutex);
 274
 275         return 0;
 276 }
 277
 278 static ssize_t
 279 event_trigger_write(struct file *filp, const char __user *ubuf,
 280                     size_t cnt, loff_t *ppos)
 281 {
 282         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 283 }
 284
 285 static int
 286 event_trigger_open(struct inode *inode, struct file *filp)
 287 {
 288         return event_trigger_regex_open(inode, filp);
 289 }
 290
 291 static int
 292 event_trigger_release(struct inode *inode, struct file *file)
 293 {
 294         return event_trigger_regex_release(inode, file);
 295 }
 296
 297 const struct file_operations event_trigger_fops = {
 298         .open = event_trigger_open,
 299         .read = seq_read,
 300         .write = event_trigger_write,
 301         .llseek = tracing_lseek,
 302         .release = event_trigger_release,
 303 };
 304
 305 /*
 306  * Currently we only register event commands from __init, so mark this
 307  * __init too.
 308  */
 309 static __init int register_event_command(struct event_command *cmd)
 310 {
 311         struct event_command *p;
 312         int ret = 0;
 313
 314         mutex_lock(&trigger_cmd_mutex);
 315         list_for_each_entry(p, &trigger_commands, list) {
 316                 if (strcmp(cmd->name, p->name) == 0) {
 317                         ret = -EBUSY;
 318                         goto out_unlock;
 319                 }
 320         }
 321         list_add(&cmd->list, &trigger_commands);
 322  out_unlock:
 323         mutex_unlock(&trigger_cmd_mutex);
 324
 325         return ret;
 326 }
 327
 328 /*
 329  * Currently we only unregister event commands from __init, so mark
 330  * this __init too.
 331  */
 332 static __init int unregister_event_command(struct event_command *cmd)
 333 {
 334         struct event_command *p, *n;
 335         int ret = -ENODEV;
 336
 337         mutex_lock(&trigger_cmd_mutex);
 338         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 339                 if (strcmp(cmd->name, p->name) == 0) {
 340                         ret = 0;
 341                         list_del_init(&p->list);
 342                         goto out_unlock;
 343                 }
 344         }
 345  out_unlock:
 346         mutex_unlock(&trigger_cmd_mutex);
 347
 348         return ret;
 349 }
 350
 351 /**
 352  * event_trigger_print - Generic event_trigger_ops @print implementation
 353  * @name: The name of the event trigger
 354  * @m: The seq_file being printed to
 355  * @data: Trigger-specific data
 356  * @filter_str: filter_str to print, if present
 357  *
 358  * Common implementation for event triggers to print themselves.
 359  *
 360  * Usually wrapped by a function that simply sets the @name of the
 361  * trigger command and then invokes this.
 362  *
 363  * Return: 0 on success, errno otherwise
 364  */
 365 static int
 366 event_trigger_print(const char *name, struct seq_file *m,
 367                     void *data, char *filter_str)
 368 {
 369         long count = (long)data;
 370
 371         seq_puts(m, name);
 372
 373         if (count == -1)
 374                 seq_puts(m, ":unlimited");
 375         else
 376                 seq_printf(m, ":count=%ld", count);
 377
 378         if (filter_str)
 379                 seq_printf(m, " if %s\n", filter_str);
 380         else
 381                 seq_putc(m, '\n');
 382
 383         return 0;
 384 }
 385
 386 /**
 387  * event_trigger_init - Generic event_trigger_ops @init implementation
 388  * @ops: The trigger ops associated with the trigger
 389  * @data: Trigger-specific data
 390  *
 391  * Common implementation of event trigger initialization.
 392  *
 393  * Usually used directly as the @init method in event trigger
 394  * implementations.
 395  *
 396  * Return: 0 on success, errno otherwise
 397  */
 398 static int
 399 event_trigger_init(struct event_trigger_ops *ops,
 400                    struct event_trigger_data *data)
 401 {
 402         data->ref++;
 403         return 0;
 404 }
 405
 406 /**
 407  * event_trigger_free - Generic event_trigger_ops @free implementation
 408  * @ops: The trigger ops associated with the trigger
 409  * @data: Trigger-specific data
 410  *
 411  * Common implementation of event trigger de-initialization.
 412  *
 413  * Usually used directly as the @free method in event trigger
 414  * implementations.
 415  */
 416 static void
 417 event_trigger_free(struct event_trigger_ops *ops,
 418                    struct event_trigger_data *data)
 419 {
 420         if (WARN_ON_ONCE(data->ref <= 0))
 421                 return;
 422
 423         data->ref--;
 424         if (!data->ref)
 425                 trigger_data_free(data);
 426 }
 427
 428 static int trace_event_trigger_enable_disable(struct trace_event_file *file,
 429                                               int trigger_enable)
 430 {
 431         int ret = 0;
 432
 433         if (trigger_enable) {
 434                 if (atomic_inc_return(&file->tm_ref) > 1)
 435                         return ret;
 436                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 437                 ret = trace_event_enable_disable(file, 1, 1);
 438         } else {
 439                 if (atomic_dec_return(&file->tm_ref) > 0)
 440                         return ret;
 441                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 442                 ret = trace_event_enable_disable(file, 0, 1);
 443         }
 444
 445         return ret;
 446 }
 447
 448 /**
 449  * clear_event_triggers - Clear all triggers associated with a trace array
 450  * @tr: The trace array to clear
 451  *
 452  * For each trigger, the triggering event has its tm_ref decremented
 453  * via trace_event_trigger_enable_disable(), and any associated event
 454  * (in the case of enable/disable_event triggers) will have its sm_ref
 455  * decremented via free()->trace_event_enable_disable().  That
 456  * combination effectively reverses the soft-mode/trigger state added
 457  * by trigger registration.
 458  *
 459  * Must be called with event_mutex held.
 460  */
 461 void
 462 clear_event_triggers(struct trace_array *tr)
 463 {
 464         struct trace_event_file *file;
 465
 466         list_for_each_entry(file, &tr->events, list) {
 467                 struct event_trigger_data *data;
 468                 list_for_each_entry_rcu(data, &file->triggers, list) {
 469                         trace_event_trigger_enable_disable(file, 0);
 470                         if (data->ops->free)
 471                                 data->ops->free(data->ops, data);
 472                 }
 473         }
 474 }
 475
 476 /**
 477  * update_cond_flag - Set or reset the TRIGGER_COND bit
 478  * @file: The trace_event_file associated with the event
 479  *
 480  * If an event has triggers and any of those triggers has a filter or
 481  * a post_trigger, trigger invocation needs to be deferred until after
 482  * the current event has logged its data, and the event should have
 483  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 484  * cleared.
 485  */
 486 static void update_cond_flag(struct trace_event_file *file)
 487 {
 488         struct event_trigger_data *data;
 489         bool set_cond = false;
 490
 491         list_for_each_entry_rcu(data, &file->triggers, list) {
 492                 if (data->filter || data->cmd_ops->post_trigger) {
 493                         set_cond = true;
 494                         break;
 495                 }
 496         }
 497
 498         if (set_cond)
 499                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 500         else
 501                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 502 }
 503
 504 /**
 505  * register_trigger - Generic event_command @reg implementation
 506  * @glob: The raw string used to register the trigger
 507  * @ops: The trigger ops associated with the trigger
 508  * @data: Trigger-specific data to associate with the trigger
 509  * @file: The trace_event_file associated with the event
 510  *
 511  * Common implementation for event trigger registration.
 512  *
 513  * Usually used directly as the @reg method in event command
 514  * implementations.
 515  *
 516  * Return: 0 on success, errno otherwise
 517  */
 518 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 519                             struct event_trigger_data *data,
 520                             struct trace_event_file *file)
 521 {
 522         struct event_trigger_data *test;
 523         int ret = 0;
 524
 525         list_for_each_entry_rcu(test, &file->triggers, list) {
 526                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 527                         ret = -EEXIST;
 528                         goto out;
 529                 }
 530         }
 531
 532         if (data->ops->init) {
 533                 ret = data->ops->init(data->ops, data);
 534                 if (ret < 0)
 535                         goto out;
 536         }
 537
 538         list_add_rcu(&data->list, &file->triggers);
 539         ret++;
 540
 541         update_cond_flag(file);
 542         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 543                 list_del_rcu(&data->list);
 544                 update_cond_flag(file);
 545                 ret--;
 546         }
 547 out:
 548         return ret;
 549 }
 550
 551 /**
 552  * unregister_trigger - Generic event_command @unreg implementation
 553  * @glob: The raw string used to register the trigger
 554  * @ops: The trigger ops associated with the trigger
 555  * @test: Trigger-specific data used to find the trigger to remove
 556  * @file: The trace_event_file associated with the event
 557  *
 558  * Common implementation for event trigger unregistration.
 559  *
 560  * Usually used directly as the @unreg method in event command
 561  * implementations.
 562  */
 563 static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 564                                struct event_trigger_data *test,
 565                                struct trace_event_file *file)
 566 {
 567         struct event_trigger_data *data;
 568         bool unregistered = false;
 569
 570         list_for_each_entry_rcu(data, &file->triggers, list) {
 571                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 572                         unregistered = true;
 573                         list_del_rcu(&data->list);
 574                         trace_event_trigger_enable_disable(file, 0);
 575                         update_cond_flag(file);
 576                         break;
 577                 }
 578         }
 579
 580         if (unregistered && data->ops->free)
 581                 data->ops->free(data->ops, data);
 582 }
 583
 584 /**
 585  * event_trigger_callback - Generic event_command @func implementation
 586  * @cmd_ops: The command ops, used for trigger registration
 587  * @file: The trace_event_file associated with the event
 588  * @glob: The raw string used to register the trigger
 589  * @cmd: The cmd portion of the string used to register the trigger
 590  * @param: The params portion of the string used to register the trigger
 591  *
 592  * Common implementation for event command parsing and trigger
 593  * instantiation.
 594  *
 595  * Usually used directly as the @func method in event command
 596  * implementations.
 597  *
 598  * Return: 0 on success, errno otherwise
 599  */
 600 static int
 601 event_trigger_callback(struct event_command *cmd_ops,
 602                        struct trace_event_file *file,
 603                        char *glob, char *cmd, char *param)
 604 {
 605         struct event_trigger_data *trigger_data;
 606         struct event_trigger_ops *trigger_ops;
 607         char *trigger = NULL;
 608         char *number;
 609         int ret;
 610
 611         /* separate the trigger from the filter (t:n [if filter]) */
 612         if (param && isdigit(param[0]))
 613                 trigger = strsep(&param, " \t");
 614
 615         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 616
 617         ret = -ENOMEM;
 618         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 619         if (!trigger_data)
 620                 goto out;
 621
 622         trigger_data->count = -1;
 623         trigger_data->ops = trigger_ops;
 624         trigger_data->cmd_ops = cmd_ops;
 625         INIT_LIST_HEAD(&trigger_data->list);
 626
 627         if (glob[0] == '!') {
 628                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 629                 kfree(trigger_data);
 630                 ret = 0;
 631                 goto out;
 632         }
 633
 634         if (trigger) {
 635                 number = strsep(&trigger, ":");
 636
 637                 ret = -EINVAL;
 638                 if (!strlen(number))
 639                         goto out_free;
 640
 641                 /*
 642                  * We use the callback data field (which is a pointer)
 643                  * as our counter.
 644                  */
 645                 ret = kstrtoul(number, 0, &trigger_data->count);
 646                 if (ret)
 647                         goto out_free;
 648         }
 649
 650         if (!param) /* if param is non-empty, it's supposed to be a filter */
 651                 goto out_reg;
 652
 653         if (!cmd_ops->set_filter)
 654                 goto out_reg;
 655
 656         ret = cmd_ops->set_filter(param, trigger_data, file);
 657         if (ret < 0)
 658                 goto out_free;
 659
 660  out_reg:
 661         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 662         /*
 663          * The above returns on success the # of functions enabled,
 664          * but if it didn't find any functions it returns zero.
 665          * Consider no functions a failure too.
 666          */
 667         if (!ret) {
 668                 ret = -ENOENT;
 669                 goto out_free;
 670         } else if (ret < 0)
 671                 goto out_free;
 672         ret = 0;
 673  out:
 674         return ret;
 675
 676  out_free:
 677         if (cmd_ops->set_filter)
 678                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 679         kfree(trigger_data);
 680         goto out;
 681 }
 682
 683 /**
 684  * set_trigger_filter - Generic event_command @set_filter implementation
 685  * @filter_str: The filter string for the trigger, NULL to remove filter
 686  * @trigger_data: Trigger-specific data
 687  * @file: The trace_event_file associated with the event
 688  *
 689  * Common implementation for event command filter parsing and filter
 690  * instantiation.
 691  *
 692  * Usually used directly as the @set_filter method in event command
 693  * implementations.
 694  *
 695  * Also used to remove a filter (if filter_str = NULL).
 696  *
 697  * Return: 0 on success, errno otherwise
 698  */
 699 static int set_trigger_filter(char *filter_str,
 700                               struct event_trigger_data *trigger_data,
 701                               struct trace_event_file *file)
 702 {
 703         struct event_trigger_data *data = trigger_data;
 704         struct event_filter *filter = NULL, *tmp;
 705         int ret = -EINVAL;
 706         char *s;
 707
 708         if (!filter_str) /* clear the current filter */
 709                 goto assign;
 710
 711         s = strsep(&filter_str, " \t");
 712
 713         if (!strlen(s) || strcmp(s, "if") != 0)
 714                 goto out;
 715
 716         if (!filter_str)
 717                 goto out;
 718
 719         /* The filter is for the 'trigger' event, not the triggered event */
 720         ret = create_event_filter(file->event_call, filter_str, false, &filter);
 721         if (ret)
 722                 goto out;
 723  assign:
 724         tmp = rcu_access_pointer(data->filter);
 725
 726         rcu_assign_pointer(data->filter, filter);
 727
 728         if (tmp) {
 729                 /* Make sure the call is done with the filter */
 730                 synchronize_sched();
 731                 free_event_filter(tmp);
 732         }
 733
 734         kfree(data->filter_str);
 735         data->filter_str = NULL;
 736
 737         if (filter_str) {
 738                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 739                 if (!data->filter_str) {
 740                         free_event_filter(rcu_access_pointer(data->filter));
 741                         data->filter = NULL;
 742                         ret = -ENOMEM;
 743                 }
 744         }
 745  out:
 746         return ret;
 747 }
 748
 749 static void
 750 traceon_trigger(struct event_trigger_data *data)
 751 {
 752         if (tracing_is_on())
 753                 return;
 754
 755         tracing_on();
 756 }
 757
 758 static void
 759 traceon_count_trigger(struct event_trigger_data *data)
 760 {
 761         if (tracing_is_on())
 762                 return;
 763
 764         if (!data->count)
 765                 return;
 766
 767         if (data->count != -1)
 768                 (data->count)--;
 769
 770         tracing_on();
 771 }
 772
 773 static void
 774 traceoff_trigger(struct event_trigger_data *data)
 775 {
 776         if (!tracing_is_on())
 777                 return;
 778
 779         tracing_off();
 780 }
 781
 782 static void
 783 traceoff_count_trigger(struct event_trigger_data *data)
 784 {
 785         if (!tracing_is_on())
 786                 return;
 787
 788         if (!data->count)
 789                 return;
 790
 791         if (data->count != -1)
 792                 (data->count)--;
 793
 794         tracing_off();
 795 }
 796
 797 static int
 798 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 799                       struct event_trigger_data *data)
 800 {
 801         return event_trigger_print("traceon", m, (void *)data->count,
 802                                    data->filter_str);
 803 }
 804
 805 static int
 806 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 807                        struct event_trigger_data *data)
 808 {
 809         return event_trigger_print("traceoff", m, (void *)data->count,
 810                                    data->filter_str);
 811 }
 812
 813 static struct event_trigger_ops traceon_trigger_ops = {
 814         .func                   = traceon_trigger,
 815         .print                  = traceon_trigger_print,
 816         .init                   = event_trigger_init,
 817         .free                   = event_trigger_free,
 818 };
 819
 820 static struct event_trigger_ops traceon_count_trigger_ops = {
 821         .func                   = traceon_count_trigger,
 822         .print                  = traceon_trigger_print,
 823         .init                   = event_trigger_init,
 824         .free                   = event_trigger_free,
 825 };
 826
 827 static struct event_trigger_ops traceoff_trigger_ops = {
 828         .func                   = traceoff_trigger,
 829         .print                  = traceoff_trigger_print,
 830         .init                   = event_trigger_init,
 831         .free                   = event_trigger_free,
 832 };
 833
 834 static struct event_trigger_ops traceoff_count_trigger_ops = {
 835         .func                   = traceoff_count_trigger,
 836         .print                  = traceoff_trigger_print,
 837         .init                   = event_trigger_init,
 838         .free                   = event_trigger_free,
 839 };
 840
 841 static struct event_trigger_ops *
 842 onoff_get_trigger_ops(char *cmd, char *param)
 843 {
 844         struct event_trigger_ops *ops;
 845
 846         /* we register both traceon and traceoff to this callback */
 847         if (strcmp(cmd, "traceon") == 0)
 848                 ops = param ? &traceon_count_trigger_ops :
 849                         &traceon_trigger_ops;
 850         else
 851                 ops = param ? &traceoff_count_trigger_ops :
 852                         &traceoff_trigger_ops;
 853
 854         return ops;
 855 }
 856
 857 static struct event_command trigger_traceon_cmd = {
 858         .name                   = "traceon",
 859         .trigger_type           = ETT_TRACE_ONOFF,
 860         .func                   = event_trigger_callback,
 861         .reg                    = register_trigger,
 862         .unreg                  = unregister_trigger,
 863         .get_trigger_ops        = onoff_get_trigger_ops,
 864         .set_filter             = set_trigger_filter,
 865 };
 866
 867 static struct event_command trigger_traceoff_cmd = {
 868         .name                   = "traceoff",
 869         .trigger_type           = ETT_TRACE_ONOFF,
 870         .func                   = event_trigger_callback,
 871         .reg                    = register_trigger,
 872         .unreg                  = unregister_trigger,
 873         .get_trigger_ops        = onoff_get_trigger_ops,
 874         .set_filter             = set_trigger_filter,
 875 };
 876
 877 #ifdef CONFIG_TRACER_SNAPSHOT
 878 static void
 879 snapshot_trigger(struct event_trigger_data *data)
 880 {
 881         tracing_snapshot();
 882 }
 883
 884 static void
 885 snapshot_count_trigger(struct event_trigger_data *data)
 886 {
 887         if (!data->count)
 888                 return;
 889
 890         if (data->count != -1)
 891                 (data->count)--;
 892
 893         snapshot_trigger(data);
 894 }
 895
 896 static int
 897 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
 898                           struct event_trigger_data *data,
 899                           struct trace_event_file *file)
 900 {
 901         int ret = register_trigger(glob, ops, data, file);
 902
 903         if (ret > 0 && tracing_alloc_snapshot() != 0) {
 904                 unregister_trigger(glob, ops, data, file);
 905                 ret = 0;
 906         }
 907
 908         return ret;
 909 }
 910
 911 static int
 912 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 913                        struct event_trigger_data *data)
 914 {
 915         return event_trigger_print("snapshot", m, (void *)data->count,
 916                                    data->filter_str);
 917 }
 918
 919 static struct event_trigger_ops snapshot_trigger_ops = {
 920         .func                   = snapshot_trigger,
 921         .print                  = snapshot_trigger_print,
 922         .init                   = event_trigger_init,
 923         .free                   = event_trigger_free,
 924 };
 925
 926 static struct event_trigger_ops snapshot_count_trigger_ops = {
 927         .func                   = snapshot_count_trigger,
 928         .print                  = snapshot_trigger_print,
 929         .init                   = event_trigger_init,
 930         .free                   = event_trigger_free,
 931 };
 932
 933 static struct event_trigger_ops *
 934 snapshot_get_trigger_ops(char *cmd, char *param)
 935 {
 936         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
 937 }
 938
 939 static struct event_command trigger_snapshot_cmd = {
 940         .name                   = "snapshot",
 941         .trigger_type           = ETT_SNAPSHOT,
 942         .func                   = event_trigger_callback,
 943         .reg                    = register_snapshot_trigger,
 944         .unreg                  = unregister_trigger,
 945         .get_trigger_ops        = snapshot_get_trigger_ops,
 946         .set_filter             = set_trigger_filter,
 947 };
 948
 949 static __init int register_trigger_snapshot_cmd(void)
 950 {
 951         int ret;
 952
 953         ret = register_event_command(&trigger_snapshot_cmd);
 954         WARN_ON(ret < 0);
 955
 956         return ret;
 957 }
 958 #else
 959 static __init int register_trigger_snapshot_cmd(void) { return 0; }
 960 #endif /* CONFIG_TRACER_SNAPSHOT */
 961
 962 #ifdef CONFIG_STACKTRACE
 963 /*
 964  * Skip 3:
 965  *   stacktrace_trigger()
 966  *   event_triggers_post_call()
 967  *   trace_event_raw_event_xxx()
 968  */
 969 #define STACK_SKIP 3
 970
 971 static void
 972 stacktrace_trigger(struct event_trigger_data *data)
 973 {
 974         trace_dump_stack(STACK_SKIP);
 975 }
 976
 977 static void
 978 stacktrace_count_trigger(struct event_trigger_data *data)
 979 {
 980         if (!data->count)
 981                 return;
 982
 983         if (data->count != -1)
 984                 (data->count)--;
 985
 986         stacktrace_trigger(data);
 987 }
 988
 989 static int
 990 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 991                          struct event_trigger_data *data)
 992 {
 993         return event_trigger_print("stacktrace", m, (void *)data->count,
 994                                    data->filter_str);
 995 }
 996
 997 static struct event_trigger_ops stacktrace_trigger_ops = {
 998         .func                   = stacktrace_trigger,
 999         .print                  = stacktrace_trigger_print,
1000         .init                   = event_trigger_init,
1001         .free                   = event_trigger_free,
1002 };
1003
1004 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1005         .func                   = stacktrace_count_trigger,
1006         .print                  = stacktrace_trigger_print,
1007         .init                   = event_trigger_init,
1008         .free                   = event_trigger_free,
1009 };
1010
1011 static struct event_trigger_ops *
1012 stacktrace_get_trigger_ops(char *cmd, char *param)
1013 {
1014         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1015 }
1016
1017 static struct event_command trigger_stacktrace_cmd = {
1018         .name                   = "stacktrace",
1019         .trigger_type           = ETT_STACKTRACE,
1020         .post_trigger           = true,
1021         .func                   = event_trigger_callback,
1022         .reg                    = register_trigger,
1023         .unreg                  = unregister_trigger,
1024         .get_trigger_ops        = stacktrace_get_trigger_ops,
1025         .set_filter             = set_trigger_filter,
1026 };
1027
1028 static __init int register_trigger_stacktrace_cmd(void)
1029 {
1030         int ret;
1031
1032         ret = register_event_command(&trigger_stacktrace_cmd);
1033         WARN_ON(ret < 0);
1034
1035         return ret;
1036 }
1037 #else
1038 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1039 #endif /* CONFIG_STACKTRACE */
1040
1041 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1042 {
1043         unregister_event_command(&trigger_traceon_cmd);
1044         unregister_event_command(&trigger_traceoff_cmd);
1045 }
1046
1047 /* Avoid typos */
1048 #define ENABLE_EVENT_STR        "enable_event"
1049 #define DISABLE_EVENT_STR       "disable_event"
1050
1051 struct enable_trigger_data {
1052         struct trace_event_file         *file;
1053         bool                            enable;
1054 };
1055
1056 static void
1057 event_enable_trigger(struct event_trigger_data *data)
1058 {
1059         struct enable_trigger_data *enable_data = data->private_data;
1060
1061         if (enable_data->enable)
1062                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1063         else
1064                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1065 }
1066
1067 static void
1068 event_enable_count_trigger(struct event_trigger_data *data)
1069 {
1070         struct enable_trigger_data *enable_data = data->private_data;
1071
1072         if (!data->count)
1073                 return;
1074
1075         /* Skip if the event is in a state we want to switch to */
1076         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1077                 return;
1078
1079         if (data->count != -1)
1080                 (data->count)--;
1081
1082         event_enable_trigger(data);
1083 }
1084
1085 static int
1086 event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1087                            struct event_trigger_data *data)
1088 {
1089         struct enable_trigger_data *enable_data = data->private_data;
1090
1091         seq_printf(m, "%s:%s:%s",
1092                    enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1093                    enable_data->file->event_call->class->system,
1094                    trace_event_name(enable_data->file->event_call));
1095
1096         if (data->count == -1)
1097                 seq_puts(m, ":unlimited");
1098         else
1099                 seq_printf(m, ":count=%ld", data->count);
1100
1101         if (data->filter_str)
1102                 seq_printf(m, " if %s\n", data->filter_str);
1103         else
1104                 seq_putc(m, '\n');
1105
1106         return 0;
1107 }
1108
1109 static void
1110 event_enable_trigger_free(struct event_trigger_ops *ops,
1111                           struct event_trigger_data *data)
1112 {
1113         struct enable_trigger_data *enable_data = data->private_data;
1114
1115         if (WARN_ON_ONCE(data->ref <= 0))
1116                 return;
1117
1118         data->ref--;
1119         if (!data->ref) {
1120                 /* Remove the SOFT_MODE flag */
1121                 trace_event_enable_disable(enable_data->file, 0, 1);
1122                 module_put(enable_data->file->event_call->mod);
1123                 trigger_data_free(data);
1124                 kfree(enable_data);
1125         }
1126 }
1127
1128 static struct event_trigger_ops event_enable_trigger_ops = {
1129         .func                   = event_enable_trigger,
1130         .print                  = event_enable_trigger_print,
1131         .init                   = event_trigger_init,
1132         .free                   = event_enable_trigger_free,
1133 };
1134
1135 static struct event_trigger_ops event_enable_count_trigger_ops = {
1136         .func                   = event_enable_count_trigger,
1137         .print                  = event_enable_trigger_print,
1138         .init                   = event_trigger_init,
1139         .free                   = event_enable_trigger_free,
1140 };
1141
1142 static struct event_trigger_ops event_disable_trigger_ops = {
1143         .func                   = event_enable_trigger,
1144         .print                  = event_enable_trigger_print,
1145         .init                   = event_trigger_init,
1146         .free                   = event_enable_trigger_free,
1147 };
1148
1149 static struct event_trigger_ops event_disable_count_trigger_ops = {
1150         .func                   = event_enable_count_trigger,
1151         .print                  = event_enable_trigger_print,
1152         .init                   = event_trigger_init,
1153         .free                   = event_enable_trigger_free,
1154 };
1155
1156 static int
1157 event_enable_trigger_func(struct event_command *cmd_ops,
1158                           struct trace_event_file *file,
1159                           char *glob, char *cmd, char *param)
1160 {
1161         struct trace_event_file *event_enable_file;
1162         struct enable_trigger_data *enable_data;
1163         struct event_trigger_data *trigger_data;
1164         struct event_trigger_ops *trigger_ops;
1165         struct trace_array *tr = file->tr;
1166         const char *system;
1167         const char *event;
1168         char *trigger;
1169         char *number;
1170         bool enable;
1171         int ret;
1172
1173         if (!param)
1174                 return -EINVAL;
1175
1176         /* separate the trigger from the filter (s:e:n [if filter]) */
1177         trigger = strsep(&param, " \t");
1178         if (!trigger)
1179                 return -EINVAL;
1180
1181         system = strsep(&trigger, ":");
1182         if (!trigger)
1183                 return -EINVAL;
1184
1185         event = strsep(&trigger, ":");
1186
1187         ret = -EINVAL;
1188         event_enable_file = find_event_file(tr, system, event);
1189         if (!event_enable_file)
1190                 goto out;
1191
1192         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1193
1194         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1195
1196         ret = -ENOMEM;
1197         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1198         if (!trigger_data)
1199                 goto out;
1200
1201         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1202         if (!enable_data) {
1203                 kfree(trigger_data);
1204                 goto out;
1205         }
1206
1207         trigger_data->count = -1;
1208         trigger_data->ops = trigger_ops;
1209         trigger_data->cmd_ops = cmd_ops;
1210         INIT_LIST_HEAD(&trigger_data->list);
1211         RCU_INIT_POINTER(trigger_data->filter, NULL);
1212
1213         enable_data->enable = enable;
1214         enable_data->file = event_enable_file;
1215         trigger_data->private_data = enable_data;
1216
1217         if (glob[0] == '!') {
1218                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1219                 kfree(trigger_data);
1220                 kfree(enable_data);
1221                 ret = 0;
1222                 goto out;
1223         }
1224
1225         if (trigger) {
1226                 number = strsep(&trigger, ":");
1227
1228                 ret = -EINVAL;
1229                 if (!strlen(number))
1230                         goto out_free;
1231
1232                 /*
1233                  * We use the callback data field (which is a pointer)
1234                  * as our counter.
1235                  */
1236                 ret = kstrtoul(number, 0, &trigger_data->count);
1237                 if (ret)
1238                         goto out_free;
1239         }
1240
1241         if (!param) /* if param is non-empty, it's supposed to be a filter */
1242                 goto out_reg;
1243
1244         if (!cmd_ops->set_filter)
1245                 goto out_reg;
1246
1247         ret = cmd_ops->set_filter(param, trigger_data, file);
1248         if (ret < 0)
1249                 goto out_free;
1250
1251  out_reg:
1252         /* Don't let event modules unload while probe registered */
1253         ret = try_module_get(event_enable_file->event_call->mod);
1254         if (!ret) {
1255                 ret = -EBUSY;
1256                 goto out_free;
1257         }
1258
1259         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1260         if (ret < 0)
1261                 goto out_put;
1262         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1263         /*
1264          * The above returns on success the # of functions enabled,
1265          * but if it didn't find any functions it returns zero.
1266          * Consider no functions a failure too.
1267          */
1268         if (!ret) {
1269                 ret = -ENOENT;
1270                 goto out_disable;
1271         } else if (ret < 0)
1272                 goto out_disable;
1273         /* Just return zero, not the number of enabled functions */
1274         ret = 0;
1275  out:
1276         return ret;
1277
1278  out_disable:
1279         trace_event_enable_disable(event_enable_file, 0, 1);
1280  out_put:
1281         module_put(event_enable_file->event_call->mod);
1282  out_free:
1283         if (cmd_ops->set_filter)
1284                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1285         kfree(trigger_data);
1286         kfree(enable_data);
1287         goto out;
1288 }
1289
1290 static int event_enable_register_trigger(char *glob,
1291                                          struct event_trigger_ops *ops,
1292                                          struct event_trigger_data *data,
1293                                          struct trace_event_file *file)
1294 {
1295         struct enable_trigger_data *enable_data = data->private_data;
1296         struct enable_trigger_data *test_enable_data;
1297         struct event_trigger_data *test;
1298         int ret = 0;
1299
1300         list_for_each_entry_rcu(test, &file->triggers, list) {
1301                 test_enable_data = test->private_data;
1302                 if (test_enable_data &&
1303                     (test_enable_data->file == enable_data->file)) {
1304                         ret = -EEXIST;
1305                         goto out;
1306                 }
1307         }
1308
1309         if (data->ops->init) {
1310                 ret = data->ops->init(data->ops, data);
1311                 if (ret < 0)
1312                         goto out;
1313         }
1314
1315         list_add_rcu(&data->list, &file->triggers);
1316         ret++;
1317
1318         update_cond_flag(file);
1319         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1320                 list_del_rcu(&data->list);
1321                 update_cond_flag(file);
1322                 ret--;
1323         }
1324 out:
1325         return ret;
1326 }
1327
1328 static void event_enable_unregister_trigger(char *glob,
1329                                             struct event_trigger_ops *ops,
1330                                             struct event_trigger_data *test,
1331                                             struct trace_event_file *file)
1332 {
1333         struct enable_trigger_data *test_enable_data = test->private_data;
1334         struct enable_trigger_data *enable_data;
1335         struct event_trigger_data *data;
1336         bool unregistered = false;
1337
1338         list_for_each_entry_rcu(data, &file->triggers, list) {
1339                 enable_data = data->private_data;
1340                 if (enable_data &&
1341                     (enable_data->file == test_enable_data->file)) {
1342                         unregistered = true;
1343                         list_del_rcu(&data->list);
1344                         trace_event_trigger_enable_disable(file, 0);
1345                         update_cond_flag(file);
1346                         break;
1347                 }
1348         }
1349
1350         if (unregistered && data->ops->free)
1351                 data->ops->free(data->ops, data);
1352 }
1353
1354 static struct event_trigger_ops *
1355 event_enable_get_trigger_ops(char *cmd, char *param)
1356 {
1357         struct event_trigger_ops *ops;
1358         bool enable;
1359
1360         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1361
1362         if (enable)
1363                 ops = param ? &event_enable_count_trigger_ops :
1364                         &event_enable_trigger_ops;
1365         else
1366                 ops = param ? &event_disable_count_trigger_ops :
1367                         &event_disable_trigger_ops;
1368
1369         return ops;
1370 }
1371
1372 static struct event_command trigger_enable_cmd = {
1373         .name                   = ENABLE_EVENT_STR,
1374         .trigger_type           = ETT_EVENT_ENABLE,
1375         .func                   = event_enable_trigger_func,
1376         .reg                    = event_enable_register_trigger,
1377         .unreg                  = event_enable_unregister_trigger,
1378         .get_trigger_ops        = event_enable_get_trigger_ops,
1379         .set_filter             = set_trigger_filter,
1380 };
1381
1382 static struct event_command trigger_disable_cmd = {
1383         .name                   = DISABLE_EVENT_STR,
1384         .trigger_type           = ETT_EVENT_ENABLE,
1385         .func                   = event_enable_trigger_func,
1386         .reg                    = event_enable_register_trigger,
1387         .unreg                  = event_enable_unregister_trigger,
1388         .get_trigger_ops        = event_enable_get_trigger_ops,
1389         .set_filter             = set_trigger_filter,
1390 };
1391
1392 static __init void unregister_trigger_enable_disable_cmds(void)
1393 {
1394         unregister_event_command(&trigger_enable_cmd);
1395         unregister_event_command(&trigger_disable_cmd);
1396 }
1397
1398 static __init int register_trigger_enable_disable_cmds(void)
1399 {
1400         int ret;
1401
1402         ret = register_event_command(&trigger_enable_cmd);
1403         if (WARN_ON(ret < 0))
1404                 return ret;
1405         ret = register_event_command(&trigger_disable_cmd);
1406         if (WARN_ON(ret < 0))
1407                 unregister_trigger_enable_disable_cmds();
1408
1409         return ret;
1410 }
1411
1412 static __init int register_trigger_traceon_traceoff_cmds(void)
1413 {
1414         int ret;
1415
1416         ret = register_event_command(&trigger_traceon_cmd);
1417         if (WARN_ON(ret < 0))
1418                 return ret;
1419         ret = register_event_command(&trigger_traceoff_cmd);
1420         if (WARN_ON(ret < 0))
1421                 unregister_trigger_traceon_traceoff_cmds();
1422
1423         return ret;
1424 }
1425
1426 __init int register_trigger_cmds(void)
1427 {
1428         register_trigger_traceon_traceoff_cmds();
1429         register_trigger_snapshot_cmd();
1430         register_trigger_stacktrace_cmd();
1431         register_trigger_enable_disable_cmds();
1432
1433         return 0;
1434 }