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 <tom.zanussi@linux.intel.com>
  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 void trigger_data_free(struct event_trigger_data *data)
  32 {
  33         if (data->cmd_ops->set_filter)
  34                 data->cmd_ops->set_filter(NULL, data, NULL);
  35
  36         synchronize_sched(); /* make sure current triggers exit before free */
  37         kfree(data);
  38 }
  39
  40 /**
  41  * event_triggers_call - Call triggers associated with a trace event
  42  * @file: The trace_event_file associated with the event
  43  * @rec: The trace entry for the event, NULL for unconditional invocation
  44  *
  45  * For each trigger associated with an event, invoke the trigger
  46  * function registered with the associated trigger command.  If rec is
  47  * non-NULL, it means that the trigger requires further processing and
  48  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
  49  * trigger has a filter associated with it, rec will checked against
  50  * the filter and if the record matches the trigger will be invoked.
  51  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
  52  * in any case until the current event is written, the trigger
  53  * function isn't invoked but the bit associated with the deferred
  54  * trigger is set in the return value.
  55  *
  56  * Returns an enum event_trigger_type value containing a set bit for
  57  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  58  *
  59  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  60  *
  61  * Return: an enum event_trigger_type value containing a set bit for
  62  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  63  */
  64 enum event_trigger_type
  65 event_triggers_call(struct trace_event_file *file, void *rec)
  66 {
  67         struct event_trigger_data *data;
  68         enum event_trigger_type tt = ETT_NONE;
  69         struct event_filter *filter;
  70
  71         if (list_empty(&file->triggers))
  72                 return tt;
  73
  74         list_for_each_entry_rcu(data, &file->triggers, list) {
  75                 if (data->paused)
  76                         continue;
  77                 if (!rec) {
  78                         data->ops->func(data, rec);
  79                         continue;
  80                 }
  81                 filter = rcu_dereference_sched(data->filter);
  82                 if (filter && !filter_match_preds(filter, rec))
  83                         continue;
  84                 if (event_command_post_trigger(data->cmd_ops)) {
  85                         tt |= data->cmd_ops->trigger_type;
  86                         continue;
  87                 }
  88                 data->ops->func(data, rec);
  89         }
  90         return tt;
  91 }
  92 EXPORT_SYMBOL_GPL(event_triggers_call);
  93
  94 /**
  95  * event_triggers_post_call - Call 'post_triggers' for a trace event
  96  * @file: The trace_event_file associated with the event
  97  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
  98  * @rec: The trace entry for the event
  99  *
 100  * For each trigger associated with an event, invoke the trigger
 101  * function registered with the associated trigger command, if the
 102  * corresponding bit is set in the tt enum passed into this function.
 103  * See @event_triggers_call for details on how those bits are set.
 104  *
 105  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 106  */
 107 void
 108 event_triggers_post_call(struct trace_event_file *file,
 109                          enum event_trigger_type tt,
 110                          void *rec)
 111 {
 112         struct event_trigger_data *data;
 113
 114         list_for_each_entry_rcu(data, &file->triggers, list) {
 115                 if (data->paused)
 116                         continue;
 117                 if (data->cmd_ops->trigger_type & tt)
 118                         data->ops->func(data, rec);
 119         }
 120 }
 121 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 122
 123 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 124
 125 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 126 {
 127         struct trace_event_file *event_file = event_file_data(m->private);
 128
 129         if (t == SHOW_AVAILABLE_TRIGGERS) {
 130                 (*pos)++;
 131                 return NULL;
 132         }
 133         return seq_list_next(t, &event_file->triggers, pos);
 134 }
 135
 136 static void *trigger_start(struct seq_file *m, loff_t *pos)
 137 {
 138         struct trace_event_file *event_file;
 139
 140         /* ->stop() is called even if ->start() fails */
 141         mutex_lock(&event_mutex);
 142         event_file = event_file_data(m->private);
 143         if (unlikely(!event_file))
 144                 return ERR_PTR(-ENODEV);
 145
 146         if (list_empty(&event_file->triggers))
 147                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 148
 149         return seq_list_start(&event_file->triggers, *pos);
 150 }
 151
 152 static void trigger_stop(struct seq_file *m, void *t)
 153 {
 154         mutex_unlock(&event_mutex);
 155 }
 156
 157 static int trigger_show(struct seq_file *m, void *v)
 158 {
 159         struct event_trigger_data *data;
 160         struct event_command *p;
 161
 162         if (v == SHOW_AVAILABLE_TRIGGERS) {
 163                 seq_puts(m, "# Available triggers:\n");
 164                 seq_putc(m, '#');
 165                 mutex_lock(&trigger_cmd_mutex);
 166                 list_for_each_entry_reverse(p, &trigger_commands, list)
 167                         seq_printf(m, " %s", p->name);
 168                 seq_putc(m, '\n');
 169                 mutex_unlock(&trigger_cmd_mutex);
 170                 return 0;
 171         }
 172
 173         data = list_entry(v, struct event_trigger_data, list);
 174         data->ops->print(m, data->ops, data);
 175
 176         return 0;
 177 }
 178
 179 static const struct seq_operations event_triggers_seq_ops = {
 180         .start = trigger_start,
 181         .next = trigger_next,
 182         .stop = trigger_stop,
 183         .show = trigger_show,
 184 };
 185
 186 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 187 {
 188         int ret = 0;
 189
 190         mutex_lock(&event_mutex);
 191
 192         if (unlikely(!event_file_data(file))) {
 193                 mutex_unlock(&event_mutex);
 194                 return -ENODEV;
 195         }
 196
 197         if ((file->f_mode & FMODE_WRITE) &&
 198             (file->f_flags & O_TRUNC)) {
 199                 struct trace_event_file *event_file;
 200                 struct event_command *p;
 201
 202                 event_file = event_file_data(file);
 203
 204                 list_for_each_entry(p, &trigger_commands, list) {
 205                         if (p->unreg_all)
 206                                 p->unreg_all(event_file);
 207                 }
 208         }
 209
 210         if (file->f_mode & FMODE_READ) {
 211                 ret = seq_open(file, &event_triggers_seq_ops);
 212                 if (!ret) {
 213                         struct seq_file *m = file->private_data;
 214                         m->private = file;
 215                 }
 216         }
 217
 218         mutex_unlock(&event_mutex);
 219
 220         return ret;
 221 }
 222
 223 static int trigger_process_regex(struct trace_event_file *file, char *buff)
 224 {
 225         char *command, *next;
 226         struct event_command *p;
 227         int ret = -EINVAL;
 228
 229         next = buff = skip_spaces(buff);
 230         command = strsep(&next, ": \t");
 231         if (next) {
 232                 next = skip_spaces(next);
 233                 if (!*next)
 234                         next = NULL;
 235         }
 236         command = (command[0] != '!') ? command : command + 1;
 237
 238         mutex_lock(&trigger_cmd_mutex);
 239         list_for_each_entry(p, &trigger_commands, list) {
 240                 if (strcmp(p->name, command) == 0) {
 241                         ret = p->func(p, file, buff, command, next);
 242                         goto out_unlock;
 243                 }
 244         }
 245  out_unlock:
 246         mutex_unlock(&trigger_cmd_mutex);
 247
 248         return ret;
 249 }
 250
 251 static ssize_t event_trigger_regex_write(struct file *file,
 252                                          const char __user *ubuf,
 253                                          size_t cnt, loff_t *ppos)
 254 {
 255         struct trace_event_file *event_file;
 256         ssize_t ret;
 257         char *buf;
 258
 259         if (!cnt)
 260                 return 0;
 261
 262         if (cnt >= PAGE_SIZE)
 263                 return -EINVAL;
 264
 265         buf = memdup_user_nul(ubuf, cnt);
 266         if (IS_ERR(buf))
 267                 return PTR_ERR(buf);
 268
 269         strim(buf);
 270
 271         mutex_lock(&event_mutex);
 272         event_file = event_file_data(file);
 273         if (unlikely(!event_file)) {
 274                 mutex_unlock(&event_mutex);
 275                 kfree(buf);
 276                 return -ENODEV;
 277         }
 278         ret = trigger_process_regex(event_file, buf);
 279         mutex_unlock(&event_mutex);
 280
 281         kfree(buf);
 282         if (ret < 0)
 283                 goto out;
 284
 285         *ppos += cnt;
 286         ret = cnt;
 287  out:
 288         return ret;
 289 }
 290
 291 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 292 {
 293         mutex_lock(&event_mutex);
 294
 295         if (file->f_mode & FMODE_READ)
 296                 seq_release(inode, file);
 297
 298         mutex_unlock(&event_mutex);
 299
 300         return 0;
 301 }
 302
 303 static ssize_t
 304 event_trigger_write(struct file *filp, const char __user *ubuf,
 305                     size_t cnt, loff_t *ppos)
 306 {
 307         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 308 }
 309
 310 static int
 311 event_trigger_open(struct inode *inode, struct file *filp)
 312 {
 313         return event_trigger_regex_open(inode, filp);
 314 }
 315
 316 static int
 317 event_trigger_release(struct inode *inode, struct file *file)
 318 {
 319         return event_trigger_regex_release(inode, file);
 320 }
 321
 322 const struct file_operations event_trigger_fops = {
 323         .open = event_trigger_open,
 324         .read = seq_read,
 325         .write = event_trigger_write,
 326         .llseek = tracing_lseek,
 327         .release = event_trigger_release,
 328 };
 329
 330 /*
 331  * Currently we only register event commands from __init, so mark this
 332  * __init too.
 333  */
 334 __init int register_event_command(struct event_command *cmd)
 335 {
 336         struct event_command *p;
 337         int ret = 0;
 338
 339         mutex_lock(&trigger_cmd_mutex);
 340         list_for_each_entry(p, &trigger_commands, list) {
 341                 if (strcmp(cmd->name, p->name) == 0) {
 342                         ret = -EBUSY;
 343                         goto out_unlock;
 344                 }
 345         }
 346         list_add(&cmd->list, &trigger_commands);
 347  out_unlock:
 348         mutex_unlock(&trigger_cmd_mutex);
 349
 350         return ret;
 351 }
 352
 353 /*
 354  * Currently we only unregister event commands from __init, so mark
 355  * this __init too.
 356  */
 357 __init int unregister_event_command(struct event_command *cmd)
 358 {
 359         struct event_command *p, *n;
 360         int ret = -ENODEV;
 361
 362         mutex_lock(&trigger_cmd_mutex);
 363         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 364                 if (strcmp(cmd->name, p->name) == 0) {
 365                         ret = 0;
 366                         list_del_init(&p->list);
 367                         goto out_unlock;
 368                 }
 369         }
 370  out_unlock:
 371         mutex_unlock(&trigger_cmd_mutex);
 372
 373         return ret;
 374 }
 375
 376 /**
 377  * event_trigger_print - Generic event_trigger_ops @print implementation
 378  * @name: The name of the event trigger
 379  * @m: The seq_file being printed to
 380  * @data: Trigger-specific data
 381  * @filter_str: filter_str to print, if present
 382  *
 383  * Common implementation for event triggers to print themselves.
 384  *
 385  * Usually wrapped by a function that simply sets the @name of the
 386  * trigger command and then invokes this.
 387  *
 388  * Return: 0 on success, errno otherwise
 389  */
 390 static int
 391 event_trigger_print(const char *name, struct seq_file *m,
 392                     void *data, char *filter_str)
 393 {
 394         long count = (long)data;
 395
 396         seq_puts(m, name);
 397
 398         if (count == -1)
 399                 seq_puts(m, ":unlimited");
 400         else
 401                 seq_printf(m, ":count=%ld", count);
 402
 403         if (filter_str)
 404                 seq_printf(m, " if %s\n", filter_str);
 405         else
 406                 seq_putc(m, '\n');
 407
 408         return 0;
 409 }
 410
 411 /**
 412  * event_trigger_init - Generic event_trigger_ops @init implementation
 413  * @ops: The trigger ops associated with the trigger
 414  * @data: Trigger-specific data
 415  *
 416  * Common implementation of event trigger initialization.
 417  *
 418  * Usually used directly as the @init method in event trigger
 419  * implementations.
 420  *
 421  * Return: 0 on success, errno otherwise
 422  */
 423 int event_trigger_init(struct event_trigger_ops *ops,
 424                        struct event_trigger_data *data)
 425 {
 426         data->ref++;
 427         return 0;
 428 }
 429
 430 /**
 431  * event_trigger_free - Generic event_trigger_ops @free implementation
 432  * @ops: The trigger ops associated with the trigger
 433  * @data: Trigger-specific data
 434  *
 435  * Common implementation of event trigger de-initialization.
 436  *
 437  * Usually used directly as the @free method in event trigger
 438  * implementations.
 439  */
 440 static void
 441 event_trigger_free(struct event_trigger_ops *ops,
 442                    struct event_trigger_data *data)
 443 {
 444         if (WARN_ON_ONCE(data->ref <= 0))
 445                 return;
 446
 447         data->ref--;
 448         if (!data->ref)
 449                 trigger_data_free(data);
 450 }
 451
 452 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 453                                        int trigger_enable)
 454 {
 455         int ret = 0;
 456
 457         if (trigger_enable) {
 458                 if (atomic_inc_return(&file->tm_ref) > 1)
 459                         return ret;
 460                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 461                 ret = trace_event_enable_disable(file, 1, 1);
 462         } else {
 463                 if (atomic_dec_return(&file->tm_ref) > 0)
 464                         return ret;
 465                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 466                 ret = trace_event_enable_disable(file, 0, 1);
 467         }
 468
 469         return ret;
 470 }
 471
 472 /**
 473  * clear_event_triggers - Clear all triggers associated with a trace array
 474  * @tr: The trace array to clear
 475  *
 476  * For each trigger, the triggering event has its tm_ref decremented
 477  * via trace_event_trigger_enable_disable(), and any associated event
 478  * (in the case of enable/disable_event triggers) will have its sm_ref
 479  * decremented via free()->trace_event_enable_disable().  That
 480  * combination effectively reverses the soft-mode/trigger state added
 481  * by trigger registration.
 482  *
 483  * Must be called with event_mutex held.
 484  */
 485 void
 486 clear_event_triggers(struct trace_array *tr)
 487 {
 488         struct trace_event_file *file;
 489
 490         list_for_each_entry(file, &tr->events, list) {
 491                 struct event_trigger_data *data, *n;
 492                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 493                         trace_event_trigger_enable_disable(file, 0);
 494                         list_del_rcu(&data->list);
 495                         if (data->ops->free)
 496                                 data->ops->free(data->ops, data);
 497                 }
 498         }
 499 }
 500
 501 /**
 502  * update_cond_flag - Set or reset the TRIGGER_COND bit
 503  * @file: The trace_event_file associated with the event
 504  *
 505  * If an event has triggers and any of those triggers has a filter or
 506  * a post_trigger, trigger invocation needs to be deferred until after
 507  * the current event has logged its data, and the event should have
 508  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 509  * cleared.
 510  */
 511 void update_cond_flag(struct trace_event_file *file)
 512 {
 513         struct event_trigger_data *data;
 514         bool set_cond = false;
 515
 516         list_for_each_entry_rcu(data, &file->triggers, list) {
 517                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 518                     event_command_needs_rec(data->cmd_ops)) {
 519                         set_cond = true;
 520                         break;
 521                 }
 522         }
 523
 524         if (set_cond)
 525                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 526         else
 527                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 528 }
 529
 530 /**
 531  * register_trigger - Generic event_command @reg implementation
 532  * @glob: The raw string used to register the trigger
 533  * @ops: The trigger ops associated with the trigger
 534  * @data: Trigger-specific data to associate with the trigger
 535  * @file: The trace_event_file associated with the event
 536  *
 537  * Common implementation for event trigger registration.
 538  *
 539  * Usually used directly as the @reg method in event command
 540  * implementations.
 541  *
 542  * Return: 0 on success, errno otherwise
 543  */
 544 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 545                             struct event_trigger_data *data,
 546                             struct trace_event_file *file)
 547 {
 548         struct event_trigger_data *test;
 549         int ret = 0;
 550
 551         list_for_each_entry_rcu(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 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         list_for_each_entry_rcu(data, &file->triggers, list) {
 597                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 598                         unregistered = true;
 599                         list_del_rcu(&data->list);
 600                         trace_event_trigger_enable_disable(file, 0);
 601                         update_cond_flag(file);
 602                         break;
 603                 }
 604         }
 605
 606         if (unregistered && data->ops->free)
 607                 data->ops->free(data->ops, data);
 608 }
 609
 610 /**
 611  * event_trigger_callback - Generic event_command @func implementation
 612  * @cmd_ops: The command ops, used for trigger registration
 613  * @file: The trace_event_file associated with the event
 614  * @glob: The raw string used to register the trigger
 615  * @cmd: The cmd portion of the string used to register the trigger
 616  * @param: The params portion of the string used to register the trigger
 617  *
 618  * Common implementation for event command parsing and trigger
 619  * instantiation.
 620  *
 621  * Usually used directly as the @func method in event command
 622  * implementations.
 623  *
 624  * Return: 0 on success, errno otherwise
 625  */
 626 static int
 627 event_trigger_callback(struct event_command *cmd_ops,
 628                        struct trace_event_file *file,
 629                        char *glob, char *cmd, char *param)
 630 {
 631         struct event_trigger_data *trigger_data;
 632         struct event_trigger_ops *trigger_ops;
 633         char *trigger = NULL;
 634         char *number;
 635         int ret;
 636
 637         /* separate the trigger from the filter (t:n [if filter]) */
 638         if (param && isdigit(param[0])) {
 639                 trigger = strsep(&param, " \t");
 640                 if (param) {
 641                         param = skip_spaces(param);
 642                         if (!*param)
 643                                 param = NULL;
 644                 }
 645         }
 646
 647         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 648
 649         ret = -ENOMEM;
 650         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 651         if (!trigger_data)
 652                 goto out;
 653
 654         trigger_data->count = -1;
 655         trigger_data->ops = trigger_ops;
 656         trigger_data->cmd_ops = cmd_ops;
 657         INIT_LIST_HEAD(&trigger_data->list);
 658         INIT_LIST_HEAD(&trigger_data->named_list);
 659
 660         if (glob[0] == '!') {
 661                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 662                 kfree(trigger_data);
 663                 ret = 0;
 664                 goto out;
 665         }
 666
 667         if (trigger) {
 668                 number = strsep(&trigger, ":");
 669
 670                 ret = -EINVAL;
 671                 if (!strlen(number))
 672                         goto out_free;
 673
 674                 /*
 675                  * We use the callback data field (which is a pointer)
 676                  * as our counter.
 677                  */
 678                 ret = kstrtoul(number, 0, &trigger_data->count);
 679                 if (ret)
 680                         goto out_free;
 681         }
 682
 683         if (!param) /* if param is non-empty, it's supposed to be a filter */
 684                 goto out_reg;
 685
 686         if (!cmd_ops->set_filter)
 687                 goto out_reg;
 688
 689         ret = cmd_ops->set_filter(param, trigger_data, file);
 690         if (ret < 0)
 691                 goto out_free;
 692
 693  out_reg:
 694         /* Up the trigger_data count to make sure reg doesn't free it on failure */
 695         event_trigger_init(trigger_ops, trigger_data);
 696         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 697         /*
 698          * The above returns on success the # of functions enabled,
 699          * but if it didn't find any functions it returns zero.
 700          * Consider no functions a failure too.
 701          */
 702         if (!ret) {
 703                 cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 704                 ret = -ENOENT;
 705         } else if (ret > 0)
 706                 ret = 0;
 707
 708         /* Down the counter of trigger_data or free it if not used anymore */
 709         event_trigger_free(trigger_ops, trigger_data);
 710  out:
 711         return ret;
 712
 713  out_free:
 714         if (cmd_ops->set_filter)
 715                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 716         kfree(trigger_data);
 717         goto out;
 718 }
 719
 720 /**
 721  * set_trigger_filter - Generic event_command @set_filter implementation
 722  * @filter_str: The filter string for the trigger, NULL to remove filter
 723  * @trigger_data: Trigger-specific data
 724  * @file: The trace_event_file associated with the event
 725  *
 726  * Common implementation for event command filter parsing and filter
 727  * instantiation.
 728  *
 729  * Usually used directly as the @set_filter method in event command
 730  * implementations.
 731  *
 732  * Also used to remove a filter (if filter_str = NULL).
 733  *
 734  * Return: 0 on success, errno otherwise
 735  */
 736 int set_trigger_filter(char *filter_str,
 737                        struct event_trigger_data *trigger_data,
 738                        struct trace_event_file *file)
 739 {
 740         struct event_trigger_data *data = trigger_data;
 741         struct event_filter *filter = NULL, *tmp;
 742         int ret = -EINVAL;
 743         char *s;
 744
 745         if (!filter_str) /* clear the current filter */
 746                 goto assign;
 747
 748         s = strsep(&filter_str, " \t");
 749
 750         if (!strlen(s) || strcmp(s, "if") != 0)
 751                 goto out;
 752
 753         if (!filter_str)
 754                 goto out;
 755
 756         /* The filter is for the 'trigger' event, not the triggered event */
 757         ret = create_event_filter(file->event_call, filter_str, false, &filter);
 758         /*
 759          * If create_event_filter() fails, filter still needs to be freed.
 760          * Which the calling code will do with data->filter.
 761          */
 762  assign:
 763         tmp = rcu_access_pointer(data->filter);
 764
 765         rcu_assign_pointer(data->filter, filter);
 766
 767         if (tmp) {
 768                 /* Make sure the call is done with the filter */
 769                 synchronize_sched();
 770                 free_event_filter(tmp);
 771         }
 772
 773         kfree(data->filter_str);
 774         data->filter_str = NULL;
 775
 776         if (filter_str) {
 777                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 778                 if (!data->filter_str) {
 779                         free_event_filter(rcu_access_pointer(data->filter));
 780                         data->filter = NULL;
 781                         ret = -ENOMEM;
 782                 }
 783         }
 784  out:
 785         return ret;
 786 }
 787
 788 static LIST_HEAD(named_triggers);
 789
 790 /**
 791  * find_named_trigger - Find the common named trigger associated with @name
 792  * @name: The name of the set of named triggers to find the common data for
 793  *
 794  * Named triggers are sets of triggers that share a common set of
 795  * trigger data.  The first named trigger registered with a given name
 796  * owns the common trigger data that the others subsequently
 797  * registered with the same name will reference.  This function
 798  * returns the common trigger data associated with that first
 799  * registered instance.
 800  *
 801  * Return: the common trigger data for the given named trigger on
 802  * success, NULL otherwise.
 803  */
 804 struct event_trigger_data *find_named_trigger(const char *name)
 805 {
 806         struct event_trigger_data *data;
 807
 808         if (!name)
 809                 return NULL;
 810
 811         list_for_each_entry(data, &named_triggers, named_list) {
 812                 if (data->named_data)
 813                         continue;
 814                 if (strcmp(data->name, name) == 0)
 815                         return data;
 816         }
 817
 818         return NULL;
 819 }
 820
 821 /**
 822  * is_named_trigger - determine if a given trigger is a named trigger
 823  * @test: The trigger data to test
 824  *
 825  * Return: true if 'test' is a named trigger, false otherwise.
 826  */
 827 bool is_named_trigger(struct event_trigger_data *test)
 828 {
 829         struct event_trigger_data *data;
 830
 831         list_for_each_entry(data, &named_triggers, named_list) {
 832                 if (test == data)
 833                         return true;
 834         }
 835
 836         return false;
 837 }
 838
 839 /**
 840  * save_named_trigger - save the trigger in the named trigger list
 841  * @name: The name of the named trigger set
 842  * @data: The trigger data to save
 843  *
 844  * Return: 0 if successful, negative error otherwise.
 845  */
 846 int save_named_trigger(const char *name, struct event_trigger_data *data)
 847 {
 848         data->name = kstrdup(name, GFP_KERNEL);
 849         if (!data->name)
 850                 return -ENOMEM;
 851
 852         list_add(&data->named_list, &named_triggers);
 853
 854         return 0;
 855 }
 856
 857 /**
 858  * del_named_trigger - delete a trigger from the named trigger list
 859  * @data: The trigger data to delete
 860  */
 861 void del_named_trigger(struct event_trigger_data *data)
 862 {
 863         kfree(data->name);
 864         data->name = NULL;
 865
 866         list_del(&data->named_list);
 867 }
 868
 869 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 870 {
 871         struct event_trigger_data *test;
 872
 873         list_for_each_entry(test, &named_triggers, named_list) {
 874                 if (strcmp(test->name, data->name) == 0) {
 875                         if (pause) {
 876                                 test->paused_tmp = test->paused;
 877                                 test->paused = true;
 878                         } else {
 879                                 test->paused = test->paused_tmp;
 880                         }
 881                 }
 882         }
 883 }
 884
 885 /**
 886  * pause_named_trigger - Pause all named triggers with the same name
 887  * @data: The trigger data of a named trigger to pause
 888  *
 889  * Pauses a named trigger along with all other triggers having the
 890  * same name.  Because named triggers share a common set of data,
 891  * pausing only one is meaningless, so pausing one named trigger needs
 892  * to pause all triggers with the same name.
 893  */
 894 void pause_named_trigger(struct event_trigger_data *data)
 895 {
 896         __pause_named_trigger(data, true);
 897 }
 898
 899 /**
 900  * unpause_named_trigger - Un-pause all named triggers with the same name
 901  * @data: The trigger data of a named trigger to unpause
 902  *
 903  * Un-pauses a named trigger along with all other triggers having the
 904  * same name.  Because named triggers share a common set of data,
 905  * unpausing only one is meaningless, so unpausing one named trigger
 906  * needs to unpause all triggers with the same name.
 907  */
 908 void unpause_named_trigger(struct event_trigger_data *data)
 909 {
 910         __pause_named_trigger(data, false);
 911 }
 912
 913 /**
 914  * set_named_trigger_data - Associate common named trigger data
 915  * @data: The trigger data of a named trigger to unpause
 916  *
 917  * Named triggers are sets of triggers that share a common set of
 918  * trigger data.  The first named trigger registered with a given name
 919  * owns the common trigger data that the others subsequently
 920  * registered with the same name will reference.  This function
 921  * associates the common trigger data from the first trigger with the
 922  * given trigger.
 923  */
 924 void set_named_trigger_data(struct event_trigger_data *data,
 925                             struct event_trigger_data *named_data)
 926 {
 927         data->named_data = named_data;
 928 }
 929
 930 static void
 931 traceon_trigger(struct event_trigger_data *data, void *rec)
 932 {
 933         if (tracing_is_on())
 934                 return;
 935
 936         tracing_on();
 937 }
 938
 939 static void
 940 traceon_count_trigger(struct event_trigger_data *data, void *rec)
 941 {
 942         if (tracing_is_on())
 943                 return;
 944
 945         if (!data->count)
 946                 return;
 947
 948         if (data->count != -1)
 949                 (data->count)--;
 950
 951         tracing_on();
 952 }
 953
 954 static void
 955 traceoff_trigger(struct event_trigger_data *data, void *rec)
 956 {
 957         if (!tracing_is_on())
 958                 return;
 959
 960         tracing_off();
 961 }
 962
 963 static void
 964 traceoff_count_trigger(struct event_trigger_data *data, void *rec)
 965 {
 966         if (!tracing_is_on())
 967                 return;
 968
 969         if (!data->count)
 970                 return;
 971
 972         if (data->count != -1)
 973                 (data->count)--;
 974
 975         tracing_off();
 976 }
 977
 978 static int
 979 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 980                       struct event_trigger_data *data)
 981 {
 982         return event_trigger_print("traceon", m, (void *)data->count,
 983                                    data->filter_str);
 984 }
 985
 986 static int
 987 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 988                        struct event_trigger_data *data)
 989 {
 990         return event_trigger_print("traceoff", m, (void *)data->count,
 991                                    data->filter_str);
 992 }
 993
 994 static struct event_trigger_ops traceon_trigger_ops = {
 995         .func                   = traceon_trigger,
 996         .print                  = traceon_trigger_print,
 997         .init                   = event_trigger_init,
 998         .free                   = event_trigger_free,
 999 };
1000
1001 static struct event_trigger_ops traceon_count_trigger_ops = {
1002         .func                   = traceon_count_trigger,
1003         .print                  = traceon_trigger_print,
1004         .init                   = event_trigger_init,
1005         .free                   = event_trigger_free,
1006 };
1007
1008 static struct event_trigger_ops traceoff_trigger_ops = {
1009         .func                   = traceoff_trigger,
1010         .print                  = traceoff_trigger_print,
1011         .init                   = event_trigger_init,
1012         .free                   = event_trigger_free,
1013 };
1014
1015 static struct event_trigger_ops traceoff_count_trigger_ops = {
1016         .func                   = traceoff_count_trigger,
1017         .print                  = traceoff_trigger_print,
1018         .init                   = event_trigger_init,
1019         .free                   = event_trigger_free,
1020 };
1021
1022 static struct event_trigger_ops *
1023 onoff_get_trigger_ops(char *cmd, char *param)
1024 {
1025         struct event_trigger_ops *ops;
1026
1027         /* we register both traceon and traceoff to this callback */
1028         if (strcmp(cmd, "traceon") == 0)
1029                 ops = param ? &traceon_count_trigger_ops :
1030                         &traceon_trigger_ops;
1031         else
1032                 ops = param ? &traceoff_count_trigger_ops :
1033                         &traceoff_trigger_ops;
1034
1035         return ops;
1036 }
1037
1038 static struct event_command trigger_traceon_cmd = {
1039         .name                   = "traceon",
1040         .trigger_type           = ETT_TRACE_ONOFF,
1041         .func                   = event_trigger_callback,
1042         .reg                    = register_trigger,
1043         .unreg                  = unregister_trigger,
1044         .get_trigger_ops        = onoff_get_trigger_ops,
1045         .set_filter             = set_trigger_filter,
1046 };
1047
1048 static struct event_command trigger_traceoff_cmd = {
1049         .name                   = "traceoff",
1050         .trigger_type           = ETT_TRACE_ONOFF,
1051         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1052         .func                   = event_trigger_callback,
1053         .reg                    = register_trigger,
1054         .unreg                  = unregister_trigger,
1055         .get_trigger_ops        = onoff_get_trigger_ops,
1056         .set_filter             = set_trigger_filter,
1057 };
1058
1059 #ifdef CONFIG_TRACER_SNAPSHOT
1060 static void
1061 snapshot_trigger(struct event_trigger_data *data, void *rec)
1062 {
1063         tracing_snapshot();
1064 }
1065
1066 static void
1067 snapshot_count_trigger(struct event_trigger_data *data, void *rec)
1068 {
1069         if (!data->count)
1070                 return;
1071
1072         if (data->count != -1)
1073                 (data->count)--;
1074
1075         snapshot_trigger(data, rec);
1076 }
1077
1078 static int
1079 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1080                           struct event_trigger_data *data,
1081                           struct trace_event_file *file)
1082 {
1083         if (tracing_alloc_snapshot() != 0)
1084                 return 0;
1085
1086         return register_trigger(glob, ops, data, file);
1087 }
1088
1089 static int
1090 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1091                        struct event_trigger_data *data)
1092 {
1093         return event_trigger_print("snapshot", m, (void *)data->count,
1094                                    data->filter_str);
1095 }
1096
1097 static struct event_trigger_ops snapshot_trigger_ops = {
1098         .func                   = snapshot_trigger,
1099         .print                  = snapshot_trigger_print,
1100         .init                   = event_trigger_init,
1101         .free                   = event_trigger_free,
1102 };
1103
1104 static struct event_trigger_ops snapshot_count_trigger_ops = {
1105         .func                   = snapshot_count_trigger,
1106         .print                  = snapshot_trigger_print,
1107         .init                   = event_trigger_init,
1108         .free                   = event_trigger_free,
1109 };
1110
1111 static struct event_trigger_ops *
1112 snapshot_get_trigger_ops(char *cmd, char *param)
1113 {
1114         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1115 }
1116
1117 static struct event_command trigger_snapshot_cmd = {
1118         .name                   = "snapshot",
1119         .trigger_type           = ETT_SNAPSHOT,
1120         .func                   = event_trigger_callback,
1121         .reg                    = register_snapshot_trigger,
1122         .unreg                  = unregister_trigger,
1123         .get_trigger_ops        = snapshot_get_trigger_ops,
1124         .set_filter             = set_trigger_filter,
1125 };
1126
1127 static __init int register_trigger_snapshot_cmd(void)
1128 {
1129         int ret;
1130
1131         ret = register_event_command(&trigger_snapshot_cmd);
1132         WARN_ON(ret < 0);
1133
1134         return ret;
1135 }
1136 #else
1137 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1138 #endif /* CONFIG_TRACER_SNAPSHOT */
1139
1140 #ifdef CONFIG_STACKTRACE
1141 /*
1142  * Skip 3:
1143  *   stacktrace_trigger()
1144  *   event_triggers_post_call()
1145  *   trace_event_raw_event_xxx()
1146  */
1147 #define STACK_SKIP 3
1148
1149 static void
1150 stacktrace_trigger(struct event_trigger_data *data, void *rec)
1151 {
1152         trace_dump_stack(STACK_SKIP);
1153 }
1154
1155 static void
1156 stacktrace_count_trigger(struct event_trigger_data *data, void *rec)
1157 {
1158         if (!data->count)
1159                 return;
1160
1161         if (data->count != -1)
1162                 (data->count)--;
1163
1164         stacktrace_trigger(data, rec);
1165 }
1166
1167 static int
1168 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1169                          struct event_trigger_data *data)
1170 {
1171         return event_trigger_print("stacktrace", m, (void *)data->count,
1172                                    data->filter_str);
1173 }
1174
1175 static struct event_trigger_ops stacktrace_trigger_ops = {
1176         .func                   = stacktrace_trigger,
1177         .print                  = stacktrace_trigger_print,
1178         .init                   = event_trigger_init,
1179         .free                   = event_trigger_free,
1180 };
1181
1182 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1183         .func                   = stacktrace_count_trigger,
1184         .print                  = stacktrace_trigger_print,
1185         .init                   = event_trigger_init,
1186         .free                   = event_trigger_free,
1187 };
1188
1189 static struct event_trigger_ops *
1190 stacktrace_get_trigger_ops(char *cmd, char *param)
1191 {
1192         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1193 }
1194
1195 static struct event_command trigger_stacktrace_cmd = {
1196         .name                   = "stacktrace",
1197         .trigger_type           = ETT_STACKTRACE,
1198         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1199         .func                   = event_trigger_callback,
1200         .reg                    = register_trigger,
1201         .unreg                  = unregister_trigger,
1202         .get_trigger_ops        = stacktrace_get_trigger_ops,
1203         .set_filter             = set_trigger_filter,
1204 };
1205
1206 static __init int register_trigger_stacktrace_cmd(void)
1207 {
1208         int ret;
1209
1210         ret = register_event_command(&trigger_stacktrace_cmd);
1211         WARN_ON(ret < 0);
1212
1213         return ret;
1214 }
1215 #else
1216 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1217 #endif /* CONFIG_STACKTRACE */
1218
1219 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1220 {
1221         unregister_event_command(&trigger_traceon_cmd);
1222         unregister_event_command(&trigger_traceoff_cmd);
1223 }
1224
1225 static void
1226 event_enable_trigger(struct event_trigger_data *data, void *rec)
1227 {
1228         struct enable_trigger_data *enable_data = data->private_data;
1229
1230         if (enable_data->enable)
1231                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1232         else
1233                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1234 }
1235
1236 static void
1237 event_enable_count_trigger(struct event_trigger_data *data, void *rec)
1238 {
1239         struct enable_trigger_data *enable_data = data->private_data;
1240
1241         if (!data->count)
1242                 return;
1243
1244         /* Skip if the event is in a state we want to switch to */
1245         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1246                 return;
1247
1248         if (data->count != -1)
1249                 (data->count)--;
1250
1251         event_enable_trigger(data, rec);
1252 }
1253
1254 int event_enable_trigger_print(struct seq_file *m,
1255                                struct event_trigger_ops *ops,
1256                                struct event_trigger_data *data)
1257 {
1258         struct enable_trigger_data *enable_data = data->private_data;
1259
1260         seq_printf(m, "%s:%s:%s",
1261                    enable_data->hist ?
1262                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1263                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1264                    enable_data->file->event_call->class->system,
1265                    trace_event_name(enable_data->file->event_call));
1266
1267         if (data->count == -1)
1268                 seq_puts(m, ":unlimited");
1269         else
1270                 seq_printf(m, ":count=%ld", data->count);
1271
1272         if (data->filter_str)
1273                 seq_printf(m, " if %s\n", data->filter_str);
1274         else
1275                 seq_putc(m, '\n');
1276
1277         return 0;
1278 }
1279
1280 void event_enable_trigger_free(struct event_trigger_ops *ops,
1281                                struct event_trigger_data *data)
1282 {
1283         struct enable_trigger_data *enable_data = data->private_data;
1284
1285         if (WARN_ON_ONCE(data->ref <= 0))
1286                 return;
1287
1288         data->ref--;
1289         if (!data->ref) {
1290                 /* Remove the SOFT_MODE flag */
1291                 trace_event_enable_disable(enable_data->file, 0, 1);
1292                 module_put(enable_data->file->event_call->mod);
1293                 trigger_data_free(data);
1294                 kfree(enable_data);
1295         }
1296 }
1297
1298 static struct event_trigger_ops event_enable_trigger_ops = {
1299         .func                   = event_enable_trigger,
1300         .print                  = event_enable_trigger_print,
1301         .init                   = event_trigger_init,
1302         .free                   = event_enable_trigger_free,
1303 };
1304
1305 static struct event_trigger_ops event_enable_count_trigger_ops = {
1306         .func                   = event_enable_count_trigger,
1307         .print                  = event_enable_trigger_print,
1308         .init                   = event_trigger_init,
1309         .free                   = event_enable_trigger_free,
1310 };
1311
1312 static struct event_trigger_ops event_disable_trigger_ops = {
1313         .func                   = event_enable_trigger,
1314         .print                  = event_enable_trigger_print,
1315         .init                   = event_trigger_init,
1316         .free                   = event_enable_trigger_free,
1317 };
1318
1319 static struct event_trigger_ops event_disable_count_trigger_ops = {
1320         .func                   = event_enable_count_trigger,
1321         .print                  = event_enable_trigger_print,
1322         .init                   = event_trigger_init,
1323         .free                   = event_enable_trigger_free,
1324 };
1325
1326 int event_enable_trigger_func(struct event_command *cmd_ops,
1327                               struct trace_event_file *file,
1328                               char *glob, char *cmd, char *param)
1329 {
1330         struct trace_event_file *event_enable_file;
1331         struct enable_trigger_data *enable_data;
1332         struct event_trigger_data *trigger_data;
1333         struct event_trigger_ops *trigger_ops;
1334         struct trace_array *tr = file->tr;
1335         const char *system;
1336         const char *event;
1337         bool hist = false;
1338         char *trigger;
1339         char *number;
1340         bool enable;
1341         int ret;
1342
1343         if (!param)
1344                 return -EINVAL;
1345
1346         /* separate the trigger from the filter (s:e:n [if filter]) */
1347         trigger = strsep(&param, " \t");
1348         if (!trigger)
1349                 return -EINVAL;
1350         if (param) {
1351                 param = skip_spaces(param);
1352                 if (!*param)
1353                         param = NULL;
1354         }
1355
1356         system = strsep(&trigger, ":");
1357         if (!trigger)
1358                 return -EINVAL;
1359
1360         event = strsep(&trigger, ":");
1361
1362         ret = -EINVAL;
1363         event_enable_file = find_event_file(tr, system, event);
1364         if (!event_enable_file)
1365                 goto out;
1366
1367 #ifdef CONFIG_HIST_TRIGGERS
1368         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1369                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1370
1371         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1372                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1373 #else
1374         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1375 #endif
1376         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1377
1378         ret = -ENOMEM;
1379         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1380         if (!trigger_data)
1381                 goto out;
1382
1383         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1384         if (!enable_data) {
1385                 kfree(trigger_data);
1386                 goto out;
1387         }
1388
1389         trigger_data->count = -1;
1390         trigger_data->ops = trigger_ops;
1391         trigger_data->cmd_ops = cmd_ops;
1392         INIT_LIST_HEAD(&trigger_data->list);
1393         RCU_INIT_POINTER(trigger_data->filter, NULL);
1394
1395         enable_data->hist = hist;
1396         enable_data->enable = enable;
1397         enable_data->file = event_enable_file;
1398         trigger_data->private_data = enable_data;
1399
1400         if (glob[0] == '!') {
1401                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1402                 kfree(trigger_data);
1403                 kfree(enable_data);
1404                 ret = 0;
1405                 goto out;
1406         }
1407
1408         /* Up the trigger_data count to make sure nothing frees it on failure */
1409         event_trigger_init(trigger_ops, trigger_data);
1410
1411         if (trigger) {
1412                 number = strsep(&trigger, ":");
1413
1414                 ret = -EINVAL;
1415                 if (!strlen(number))
1416                         goto out_free;
1417
1418                 /*
1419                  * We use the callback data field (which is a pointer)
1420                  * as our counter.
1421                  */
1422                 ret = kstrtoul(number, 0, &trigger_data->count);
1423                 if (ret)
1424                         goto out_free;
1425         }
1426
1427         if (!param) /* if param is non-empty, it's supposed to be a filter */
1428                 goto out_reg;
1429
1430         if (!cmd_ops->set_filter)
1431                 goto out_reg;
1432
1433         ret = cmd_ops->set_filter(param, trigger_data, file);
1434         if (ret < 0)
1435                 goto out_free;
1436
1437  out_reg:
1438         /* Don't let event modules unload while probe registered */
1439         ret = try_module_get(event_enable_file->event_call->mod);
1440         if (!ret) {
1441                 ret = -EBUSY;
1442                 goto out_free;
1443         }
1444
1445         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1446         if (ret < 0)
1447                 goto out_put;
1448         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1449         /*
1450          * The above returns on success the # of functions enabled,
1451          * but if it didn't find any functions it returns zero.
1452          * Consider no functions a failure too.
1453          */
1454         if (!ret) {
1455                 ret = -ENOENT;
1456                 goto out_disable;
1457         } else if (ret < 0)
1458                 goto out_disable;
1459         /* Just return zero, not the number of enabled functions */
1460         ret = 0;
1461         event_trigger_free(trigger_ops, trigger_data);
1462  out:
1463         return ret;
1464
1465  out_disable:
1466         trace_event_enable_disable(event_enable_file, 0, 1);
1467  out_put:
1468         module_put(event_enable_file->event_call->mod);
1469  out_free:
1470         if (cmd_ops->set_filter)
1471                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1472         event_trigger_free(trigger_ops, trigger_data);
1473         kfree(enable_data);
1474         goto out;
1475 }
1476
1477 int event_enable_register_trigger(char *glob,
1478                                   struct event_trigger_ops *ops,
1479                                   struct event_trigger_data *data,
1480                                   struct trace_event_file *file)
1481 {
1482         struct enable_trigger_data *enable_data = data->private_data;
1483         struct enable_trigger_data *test_enable_data;
1484         struct event_trigger_data *test;
1485         int ret = 0;
1486
1487         list_for_each_entry_rcu(test, &file->triggers, list) {
1488                 test_enable_data = test->private_data;
1489                 if (test_enable_data &&
1490                     (test->cmd_ops->trigger_type ==
1491                      data->cmd_ops->trigger_type) &&
1492                     (test_enable_data->file == enable_data->file)) {
1493                         ret = -EEXIST;
1494                         goto out;
1495                 }
1496         }
1497
1498         if (data->ops->init) {
1499                 ret = data->ops->init(data->ops, data);
1500                 if (ret < 0)
1501                         goto out;
1502         }
1503
1504         list_add_rcu(&data->list, &file->triggers);
1505         ret++;
1506
1507         update_cond_flag(file);
1508         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1509                 list_del_rcu(&data->list);
1510                 update_cond_flag(file);
1511                 ret--;
1512         }
1513 out:
1514         return ret;
1515 }
1516
1517 void event_enable_unregister_trigger(char *glob,
1518                                      struct event_trigger_ops *ops,
1519                                      struct event_trigger_data *test,
1520                                      struct trace_event_file *file)
1521 {
1522         struct enable_trigger_data *test_enable_data = test->private_data;
1523         struct enable_trigger_data *enable_data;
1524         struct event_trigger_data *data;
1525         bool unregistered = false;
1526
1527         list_for_each_entry_rcu(data, &file->triggers, list) {
1528                 enable_data = data->private_data;
1529                 if (enable_data &&
1530                     (data->cmd_ops->trigger_type ==
1531                      test->cmd_ops->trigger_type) &&
1532                     (enable_data->file == test_enable_data->file)) {
1533                         unregistered = true;
1534                         list_del_rcu(&data->list);
1535                         trace_event_trigger_enable_disable(file, 0);
1536                         update_cond_flag(file);
1537                         break;
1538                 }
1539         }
1540
1541         if (unregistered && data->ops->free)
1542                 data->ops->free(data->ops, data);
1543 }
1544
1545 static struct event_trigger_ops *
1546 event_enable_get_trigger_ops(char *cmd, char *param)
1547 {
1548         struct event_trigger_ops *ops;
1549         bool enable;
1550
1551 #ifdef CONFIG_HIST_TRIGGERS
1552         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1553                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1554 #else
1555         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1556 #endif
1557         if (enable)
1558                 ops = param ? &event_enable_count_trigger_ops :
1559                         &event_enable_trigger_ops;
1560         else
1561                 ops = param ? &event_disable_count_trigger_ops :
1562                         &event_disable_trigger_ops;
1563
1564         return ops;
1565 }
1566
1567 static struct event_command trigger_enable_cmd = {
1568         .name                   = ENABLE_EVENT_STR,
1569         .trigger_type           = ETT_EVENT_ENABLE,
1570         .func                   = event_enable_trigger_func,
1571         .reg                    = event_enable_register_trigger,
1572         .unreg                  = event_enable_unregister_trigger,
1573         .get_trigger_ops        = event_enable_get_trigger_ops,
1574         .set_filter             = set_trigger_filter,
1575 };
1576
1577 static struct event_command trigger_disable_cmd = {
1578         .name                   = DISABLE_EVENT_STR,
1579         .trigger_type           = ETT_EVENT_ENABLE,
1580         .func                   = event_enable_trigger_func,
1581         .reg                    = event_enable_register_trigger,
1582         .unreg                  = event_enable_unregister_trigger,
1583         .get_trigger_ops        = event_enable_get_trigger_ops,
1584         .set_filter             = set_trigger_filter,
1585 };
1586
1587 static __init void unregister_trigger_enable_disable_cmds(void)
1588 {
1589         unregister_event_command(&trigger_enable_cmd);
1590         unregister_event_command(&trigger_disable_cmd);
1591 }
1592
1593 static __init int register_trigger_enable_disable_cmds(void)
1594 {
1595         int ret;
1596
1597         ret = register_event_command(&trigger_enable_cmd);
1598         if (WARN_ON(ret < 0))
1599                 return ret;
1600         ret = register_event_command(&trigger_disable_cmd);
1601         if (WARN_ON(ret < 0))
1602                 unregister_trigger_enable_disable_cmds();
1603
1604         return ret;
1605 }
1606
1607 static __init int register_trigger_traceon_traceoff_cmds(void)
1608 {
1609         int ret;
1610
1611         ret = register_event_command(&trigger_traceon_cmd);
1612         if (WARN_ON(ret < 0))
1613                 return ret;
1614         ret = register_event_command(&trigger_traceoff_cmd);
1615         if (WARN_ON(ret < 0))
1616                 unregister_trigger_traceon_traceoff_cmds();
1617
1618         return ret;
1619 }
1620
1621 __init int register_trigger_cmds(void)
1622 {
1623         register_trigger_traceon_traceoff_cmds();
1624         register_trigger_snapshot_cmd();
1625         register_trigger_stacktrace_cmd();
1626         register_trigger_enable_disable_cmds();
1627         register_trigger_hist_enable_disable_cmds();
1628         register_trigger_hist_cmd();
1629
1630         return 0;
1631 }