src/bin/lttng-sessiond/event.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   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, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #define _LGPL_SOURCE
  20 #include <errno.h>
  21 #include <urcu/list.h>
  22 #include <string.h>
  23
  24 #include <lttng/lttng.h>
  25 #include <common/error.h>
  26 #include <common/sessiond-comm/sessiond-comm.h>
  27
  28 #include "channel.h"
  29 #include "event.h"
  30 #include "kernel.h"
  31 #include "lttng-sessiond.h"
  32 #include "ust-ctl.h"
  33 #include "ust-app.h"
  34 #include "trace-kernel.h"
  35 #include "trace-ust.h"
  36 #include "agent.h"
  37
  38 /*
  39  * Add unique UST event based on the event name, filter bytecode and loglevel.
  40  */
  41 static void add_unique_ust_event(struct lttng_ht *ht,
  42                 struct ltt_ust_event *event)
  43 {
  44         struct cds_lfht_node *node_ptr;
  45         struct ltt_ust_ht_key key;
  46
  47         assert(ht);
  48         assert(ht->ht);
  49         assert(event);
  50
  51         key.name = event->attr.name;
  52         key.filter = (struct lttng_filter_bytecode *) event->filter;
  53         key.loglevel = event->attr.loglevel;
  54         key.exclusion = event->exclusion;
  55
  56         node_ptr = cds_lfht_add_unique(ht->ht,
  57                         ht->hash_fct(event->node.key, lttng_ht_seed),
  58                         trace_ust_ht_match_event, &key, &event->node.node);
  59         assert(node_ptr == &event->node.node);
  60 }
  61
  62 /*
  63  * Disable kernel tracepoint event for a channel from the kernel session.
  64  */
  65 int event_kernel_disable_event(struct ltt_kernel_channel *kchan,
  66                 char *event_name)
  67 {
  68         int ret;
  69         struct ltt_kernel_event *kevent;
  70
  71         assert(kchan);
  72
  73         kevent = trace_kernel_get_event_by_name(event_name, kchan,
  74                         LTTNG_EVENT_ALL);
  75         if (kevent == NULL) {
  76                 ret = LTTNG_ERR_NO_EVENT;
  77                 goto error;
  78         }
  79
  80         ret = kernel_disable_event(kevent);
  81         if (ret < 0) {
  82                 ret = LTTNG_ERR_KERN_DISABLE_FAIL;
  83                 goto error;
  84         }
  85
  86         DBG("Kernel event %s disable for channel %s.",
  87                         kevent->event->name, kchan->channel->name);
  88
  89         ret = LTTNG_OK;
  90
  91 error:
  92         return ret;
  93 }
  94
  95 /*
  96  * Disable kernel tracepoint events for a channel from the kernel session.
  97  */
  98 int event_kernel_disable_event_type(struct ltt_kernel_channel *kchan,
  99                 enum lttng_event_type type)
 100 {
 101         int ret;
 102         struct ltt_kernel_event *kevent;
 103
 104         assert(kchan);
 105
 106         /* For each event in the kernel session */
 107         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
 108                 if (type != LTTNG_EVENT_ALL && kevent->type != type)
 109                         continue;
 110                 ret = kernel_disable_event(kevent);
 111                 if (ret < 0) {
 112                         /* We continue disabling the rest */
 113                         continue;
 114                 }
 115         }
 116         ret = LTTNG_OK;
 117         return ret;
 118 }
 119
 120 /*
 121  * Disable all kernel event for a channel from the kernel session.
 122  */
 123 int event_kernel_disable_event_all(struct ltt_kernel_channel *kchan)
 124 {
 125         return event_kernel_disable_event_type(kchan, LTTNG_EVENT_ALL);
 126 }
 127
 128 /*
 129  * Enable kernel tracepoint event for a channel from the kernel session.
 130  * We own filter_expression and filter.
 131  */
 132 int event_kernel_enable_event(struct ltt_kernel_channel *kchan,
 133                 struct lttng_event *event, char *filter_expression,
 134                 struct lttng_filter_bytecode *filter)
 135 {
 136         int ret;
 137         struct ltt_kernel_event *kevent;
 138
 139         assert(kchan);
 140         assert(event);
 141
 142         kevent = trace_kernel_find_event(event->name, kchan,
 143                         event->type, filter);
 144         if (kevent == NULL) {
 145                 ret = kernel_create_event(event, kchan,
 146                         filter_expression, filter);
 147                 /* We have passed ownership */
 148                 filter_expression = NULL;
 149                 filter = NULL;
 150                 if (ret < 0) {
 151                         switch (-ret) {
 152                         case EEXIST:
 153                                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 154                                 break;
 155                         case ENOSYS:
 156                                 ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
 157                                 break;
 158                         default:
 159                                 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 160                                 break;
 161                         }
 162                         goto end;
 163                 }
 164         } else if (kevent->enabled == 0) {
 165                 ret = kernel_enable_event(kevent);
 166                 if (ret < 0) {
 167                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 168                         goto end;
 169                 }
 170         } else {
 171                 /* At this point, the event is considered enabled */
 172                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 173                 goto end;
 174         }
 175
 176         ret = LTTNG_OK;
 177 end:
 178         free(filter_expression);
 179         free(filter);
 180         return ret;
 181 }
 182
 183 /*
 184  * ============================
 185  * UST : The Ultimate Frontier!
 186  * ============================
 187  */
 188
 189 /*
 190  * Enable UST tracepoint event for a channel from a UST session.
 191  * We own filter_expression, filter, and exclusion.
 192  */
 193 int event_ust_enable_tracepoint(struct ltt_ust_session *usess,
 194                 struct ltt_ust_channel *uchan, struct lttng_event *event,
 195                 char *filter_expression,
 196                 struct lttng_filter_bytecode *filter,
 197                 struct lttng_event_exclusion *exclusion,
 198                 bool internal_event)
 199 {
 200         int ret = LTTNG_OK, to_create = 0;
 201         struct ltt_ust_event *uevent;
 202
 203         assert(usess);
 204         assert(uchan);
 205         assert(event);
 206
 207         rcu_read_lock();
 208
 209         uevent = trace_ust_find_event(uchan->events, event->name, filter,
 210                         event->loglevel, exclusion);
 211         if (!uevent) {
 212                 uevent = trace_ust_create_event(event, filter_expression,
 213                                 filter, exclusion, internal_event);
 214                 /* We have passed ownership */
 215                 filter_expression = NULL;
 216                 filter = NULL;
 217                 exclusion = NULL;
 218                 if (uevent == NULL) {
 219                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 220                         goto error;
 221                 }
 222
 223                 /* Valid to set it after the goto error since uevent is still NULL */
 224                 to_create = 1;
 225         }
 226
 227         if (uevent->enabled) {
 228                 /* It's already enabled so everything is OK */
 229                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 230                 goto end;
 231         }
 232
 233         uevent->enabled = 1;
 234
 235         if (to_create) {
 236                 /* Create event on all UST registered apps for session */
 237                 ret = ust_app_create_event_glb(usess, uchan, uevent);
 238         } else {
 239                 /* Enable event on all UST registered apps for session */
 240                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 241         }
 242
 243         if (ret < 0) {
 244                 if (ret == -LTTNG_UST_ERR_EXIST) {
 245                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 246                         goto end;
 247                 } else {
 248                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 249                         goto error;
 250                 }
 251         }
 252
 253         if (to_create) {
 254                 /* Add ltt ust event to channel */
 255                 add_unique_ust_event(uchan->events, uevent);
 256         }
 257
 258         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 259                         to_create ? "created" : "enabled", uchan->name);
 260
 261         ret = LTTNG_OK;
 262
 263 end:
 264         rcu_read_unlock();
 265         free(filter_expression);
 266         free(filter);
 267         free(exclusion);
 268         return ret;
 269
 270 error:
 271         /*
 272          * Only destroy event on creation time (not enabling time) because if the
 273          * event is found in the channel (to_create == 0), it means that at some
 274          * point the enable_event worked and it's thus valid to keep it alive.
 275          * Destroying it also implies that we also destroy it's shadow copy to sync
 276          * everyone up.
 277          */
 278         if (to_create) {
 279                 /* In this code path, the uevent was not added to the hash table */
 280                 trace_ust_destroy_event(uevent);
 281         }
 282         rcu_read_unlock();
 283         free(filter_expression);
 284         free(filter);
 285         free(exclusion);
 286         return ret;
 287 }
 288
 289 /*
 290  * Disable UST tracepoint of a channel from a UST session.
 291  */
 292 int event_ust_disable_tracepoint(struct ltt_ust_session *usess,
 293                 struct ltt_ust_channel *uchan, char *event_name)
 294 {
 295         int ret;
 296         struct ltt_ust_event *uevent;
 297         struct lttng_ht_node_str *node;
 298         struct lttng_ht_iter iter;
 299         struct lttng_ht *ht;
 300
 301         assert(usess);
 302         assert(uchan);
 303         assert(event_name);
 304
 305         ht = uchan->events;
 306
 307         rcu_read_lock();
 308
 309         /*
 310          * We use a custom lookup since we need the iterator for the next_duplicate
 311          * call in the do while loop below.
 312          */
 313         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) event_name, lttng_ht_seed),
 314                         trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 315         node = lttng_ht_iter_get_node_str(&iter);
 316         if (node == NULL) {
 317                 DBG2("Trace UST event NOT found by name %s", event_name);
 318                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 319                 goto error;
 320         }
 321
 322         do {
 323                 uevent = caa_container_of(node, struct ltt_ust_event, node);
 324                 assert(uevent);
 325
 326                 if (uevent->enabled == 0) {
 327                         /* It's already disabled so everything is OK */
 328                         goto next;
 329                 }
 330
 331                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 332                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 333                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 334                         goto error;
 335                 }
 336                 uevent->enabled = 0;
 337
 338                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 339                                 uchan->name);
 340
 341 next:
 342                 /* Get next duplicate event by name. */
 343                 cds_lfht_next_duplicate(ht->ht, trace_ust_ht_match_event_by_name,
 344                                 event_name, &iter.iter);
 345                 node = lttng_ht_iter_get_node_str(&iter);
 346         } while (node);
 347
 348         ret = LTTNG_OK;
 349
 350 error:
 351         rcu_read_unlock();
 352         return ret;
 353 }
 354
 355 /*
 356  * Enable all agent event for a given UST session.
 357  *
 358  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 359  */
 360 int event_agent_enable_all(struct ltt_ust_session *usess,
 361                 struct agent *agt, struct lttng_event *event,
 362                 struct lttng_filter_bytecode *filter)
 363 {
 364         int ret;
 365         struct agent_event *aevent;
 366         struct lttng_ht_iter iter;
 367
 368         assert(usess);
 369
 370         DBG("Event agent enabling ALL events for session %" PRIu64, usess->id);
 371
 372         /* Enable event on agent application through TCP socket. */
 373         ret = event_agent_enable(usess, agt, event, filter);
 374         if (ret != LTTNG_OK) {
 375                 goto error;
 376         }
 377
 378         /* Flag every event that they are now enabled. */
 379         rcu_read_lock();
 380         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 381                         node.node) {
 382                 aevent->enabled = 1;
 383         }
 384         rcu_read_unlock();
 385
 386         ret = LTTNG_OK;
 387
 388 error:
 389         return ret;
 390 }
 391
 392 /*
 393  * Enable a single agent event for a given UST session.
 394  *
 395  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 396  */
 397 int event_agent_enable(struct ltt_ust_session *usess,
 398                 struct agent *agt, struct lttng_event *event,
 399                 struct lttng_filter_bytecode *filter)
 400 {
 401         int ret, created = 0;
 402         struct agent_event *aevent;
 403
 404         assert(usess);
 405         assert(event);
 406         assert(agt);
 407
 408         DBG("Event agent enabling %s for session %" PRIu64 " with loglevel type %d "
 409                         "and loglevel %d", event->name, usess->id, event->loglevel_type,
 410                         event->loglevel);
 411
 412         aevent = agent_find_event(event->name, event->loglevel, agt);
 413         if (!aevent) {
 414                 aevent = agent_create_event(event->name, filter);
 415                 if (!aevent) {
 416                         ret = LTTNG_ERR_NOMEM;
 417                         goto error;
 418                 }
 419                 aevent->loglevel = event->loglevel;
 420                 aevent->loglevel_type = event->loglevel_type;
 421                 created = 1;
 422         }
 423
 424         /* Already enabled? */
 425         if (aevent->enabled) {
 426                 goto end;
 427         }
 428
 429         ret = agent_enable_event(aevent, agt->domain);
 430         if (ret != LTTNG_OK) {
 431                 goto error;
 432         }
 433
 434         /* If the event was created prior to the enable, add it to the domain. */
 435         if (created) {
 436                 agent_add_event(aevent, agt);
 437         }
 438
 439 end:
 440         return LTTNG_OK;
 441
 442 error:
 443         if (created) {
 444                 agent_destroy_event(aevent);
 445         }
 446         return ret;
 447 }
 448
 449 /*
 450  * Return the default event name associated with the provided UST domain. Return
 451  * NULL on error.
 452  */
 453 const char *event_get_default_agent_ust_name(enum lttng_domain_type domain)
 454 {
 455         const char *default_event_name = NULL;
 456
 457         switch (domain) {
 458         case LTTNG_DOMAIN_LOG4J:
 459                 default_event_name = DEFAULT_LOG4J_EVENT_NAME;
 460                 break;
 461         case LTTNG_DOMAIN_JUL:
 462                 default_event_name = DEFAULT_JUL_EVENT_NAME;
 463                 break;
 464         case LTTNG_DOMAIN_PYTHON:
 465                 default_event_name = DEFAULT_PYTHON_EVENT_NAME;
 466                 break;
 467         default:
 468                 assert(0);
 469         }
 470
 471         return default_event_name;
 472 }
 473
 474 /*
 475  * Disable a single agent event for a given UST session.
 476  *
 477  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 478  */
 479 int event_agent_disable(struct ltt_ust_session *usess, struct agent *agt,
 480                 char *event_name)
 481 {
 482         int ret;
 483         struct agent_event *aevent;
 484         struct ltt_ust_event *uevent = NULL;
 485         struct ltt_ust_channel *uchan = NULL;
 486         const char *ust_event_name, *ust_channel_name;
 487
 488         assert(agt);
 489         assert(usess);
 490         assert(event_name);
 491
 492         DBG("Event agent disabling %s for session %" PRIu64, event_name, usess->id);
 493
 494         aevent = agent_find_event_by_name(event_name, agt);
 495         if (!aevent) {
 496                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 497                 goto error;
 498         }
 499
 500         /* Already disabled? */
 501         if (!aevent->enabled) {
 502                 goto end;
 503         }
 504
 505         if (agt->domain == LTTNG_DOMAIN_JUL) {
 506                 ust_channel_name = DEFAULT_JUL_CHANNEL_NAME;
 507         } else if (agt->domain == LTTNG_DOMAIN_LOG4J) {
 508                 ust_channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
 509         } else if (agt->domain == LTTNG_DOMAIN_PYTHON) {
 510                 ust_channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
 511         } else {
 512                 ret = LTTNG_ERR_INVALID;
 513                 goto error;
 514         }
 515
 516         /*
 517          * Disable it on the UST side. First get the channel reference then find
 518          * the event and finally disable it.
 519          */
 520         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 521                         (char *) ust_channel_name);
 522         if (!uchan) {
 523                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 524                 goto error;
 525         }
 526
 527         ust_event_name = event_get_default_agent_ust_name(agt->domain);
 528         if (!ust_event_name) {
 529                 ret = LTTNG_ERR_FATAL;
 530                 goto error;
 531         }
 532
 533         /*
 534          * The loglevel is hardcoded with 0 here since the agent ust event is set
 535          * with the loglevel type to ALL thus the loglevel stays 0. The event's
 536          * filter is the one handling the loglevel for agent.
 537          */
 538         uevent = trace_ust_find_event(uchan->events, (char *) ust_event_name,
 539                         aevent->filter, 0, NULL);
 540         /* If the agent event exists, it must be available on the UST side. */
 541         assert(uevent);
 542
 543         ret = ust_app_disable_event_glb(usess, uchan, uevent);
 544         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 545                 ret = LTTNG_ERR_UST_DISABLE_FAIL;
 546                 goto error;
 547         }
 548
 549         /*
 550          * Flag event that it's disabled so the shadow copy on the ust app side
 551          * will disable it if an application shows up.
 552          */
 553         uevent->enabled = 0;
 554
 555         ret = agent_disable_event(aevent, agt->domain);
 556         if (ret != LTTNG_OK) {
 557                 goto error;
 558         }
 559
 560 end:
 561         return LTTNG_OK;
 562
 563 error:
 564         return ret;
 565 }
 566 /*
 567  * Disable all agent event for a given UST session.
 568  *
 569  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 570  */
 571 int event_agent_disable_all(struct ltt_ust_session *usess,
 572                 struct agent *agt)
 573 {
 574         int ret;
 575         struct agent_event *aevent;
 576         struct lttng_ht_iter iter;
 577
 578         assert(agt);
 579         assert(usess);
 580
 581         /*
 582          * Disable event on agent application. Continue to disable all other events
 583          * if the * event is not found.
 584          */
 585         ret = event_agent_disable(usess, agt, "*");
 586         if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 587                 goto error;
 588         }
 589
 590         /* Flag every event that they are now enabled. */
 591         rcu_read_lock();
 592         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 593                         node.node) {
 594                 if (!aevent->enabled) {
 595                         continue;
 596                 }
 597
 598                 ret = event_agent_disable(usess, agt, aevent->name);
 599                 if (ret != LTTNG_OK) {
 600                         rcu_read_unlock();
 601                         goto error;
 602                 }
 603         }
 604         rcu_read_unlock();
 605
 606         ret = LTTNG_OK;
 607
 608 error:
 609         return ret;
 610 }