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 #include <errno.h>
  20 #include <urcu/list.h>
  21 #include <string.h>
  22
  23 #include <lttng/lttng.h>
  24 #include <common/error.h>
  25 #include <common/sessiond-comm/sessiond-comm.h>
  26
  27 #include "channel.h"
  28 #include "event.h"
  29 #include "kernel.h"
  30 #include "lttng-sessiond.h"
  31 #include "ust-ctl.h"
  32 #include "ust-app.h"
  33 #include "trace-kernel.h"
  34 #include "trace-ust.h"
  35
  36 /*
  37  * Add unique UST event based on the event name, filter bytecode and loglevel.
  38  */
  39 static void add_unique_ust_event(struct lttng_ht *ht,
  40                 struct ltt_ust_event *event)
  41 {
  42         struct cds_lfht_node *node_ptr;
  43         struct ltt_ust_ht_key key;
  44
  45         assert(ht);
  46         assert(ht->ht);
  47         assert(event);
  48
  49         key.name = event->attr.name;
  50         key.filter = (struct lttng_filter_bytecode *) event->filter;
  51         key.loglevel = event->attr.loglevel;
  52         key.exclusion = event->exclusion;
  53
  54         node_ptr = cds_lfht_add_unique(ht->ht,
  55                         ht->hash_fct(event->node.key, lttng_ht_seed),
  56                         trace_ust_ht_match_event, &key, &event->node.node);
  57         assert(node_ptr == &event->node.node);
  58 }
  59
  60 /*
  61  * Setup a lttng_event used to enable *all* syscall tracing.
  62  */
  63 static void init_syscalls_kernel_event(struct lttng_event *event)
  64 {
  65         assert(event);
  66
  67         event->name[0] = '\0';
  68         /*
  69          * We use LTTNG_EVENT* here since the trace kernel creation will make the
  70          * right changes for the kernel.
  71          */
  72         event->type = LTTNG_EVENT_SYSCALL;
  73 }
  74
  75 /*
  76  * Disable kernel tracepoint event for a channel from the kernel session.
  77  */
  78 int event_kernel_disable_tracepoint(struct ltt_kernel_channel *kchan,
  79                 char *event_name)
  80 {
  81         int ret;
  82         struct ltt_kernel_event *kevent;
  83
  84         assert(kchan);
  85
  86         kevent = trace_kernel_get_event_by_name(event_name, kchan);
  87         if (kevent == NULL) {
  88                 ret = LTTNG_ERR_NO_EVENT;
  89                 goto error;
  90         }
  91
  92         ret = kernel_disable_event(kevent);
  93         if (ret < 0) {
  94                 ret = LTTNG_ERR_KERN_DISABLE_FAIL;
  95                 goto error;
  96         }
  97
  98         DBG("Kernel event %s disable for channel %s.",
  99                         kevent->event->name, kchan->channel->name);
 100
 101         ret = LTTNG_OK;
 102
 103 error:
 104         return ret;
 105 }
 106
 107 /*
 108  * Disable kernel tracepoint events for a channel from the kernel session.
 109  */
 110 int event_kernel_disable_all_tracepoints(struct ltt_kernel_channel *kchan)
 111 {
 112         int ret;
 113         struct ltt_kernel_event *kevent;
 114
 115         assert(kchan);
 116
 117         /* For each event in the kernel session */
 118         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
 119                 ret = kernel_disable_event(kevent);
 120                 if (ret < 0) {
 121                         /* We continue disabling the rest */
 122                         continue;
 123                 }
 124         }
 125         ret = LTTNG_OK;
 126         return ret;
 127 }
 128
 129 /*
 130  * Disable kernel syscall events for a channel from the kernel session.
 131  */
 132 int event_kernel_disable_all_syscalls(struct ltt_kernel_channel *kchan)
 133 {
 134         ERR("Cannot disable syscall tracing for existing session. Please destroy session instead.");
 135         return LTTNG_OK;        /* Return OK so disable all succeeds */
 136 }
 137
 138 /*
 139  * Disable all kernel event for a channel from the kernel session.
 140  */
 141 int event_kernel_disable_all(struct ltt_kernel_channel *kchan)
 142 {
 143         int ret;
 144
 145         assert(kchan);
 146
 147         ret = event_kernel_disable_all_tracepoints(kchan);
 148         if (ret != LTTNG_OK)
 149                 return ret;
 150         ret = event_kernel_disable_all_syscalls(kchan);
 151         return ret;
 152 }
 153
 154 /*
 155  * Enable kernel tracepoint event for a channel from the kernel session.
 156  */
 157 int event_kernel_enable_tracepoint(struct ltt_kernel_channel *kchan,
 158                 struct lttng_event *event)
 159 {
 160         int ret;
 161         struct ltt_kernel_event *kevent;
 162
 163         assert(kchan);
 164         assert(event);
 165
 166         kevent = trace_kernel_get_event_by_name(event->name, kchan);
 167         if (kevent == NULL) {
 168                 ret = kernel_create_event(event, kchan);
 169                 if (ret < 0) {
 170                         switch (-ret) {
 171                         case EEXIST:
 172                                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 173                                 break;
 174                         case ENOSYS:
 175                                 ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
 176                                 break;
 177                         default:
 178                                 ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 179                                 break;
 180                         }
 181                         goto end;
 182                 }
 183         } else if (kevent->enabled == 0) {
 184                 ret = kernel_enable_event(kevent);
 185                 if (ret < 0) {
 186                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 187                         goto end;
 188                 }
 189         } else {
 190                 /* At this point, the event is considered enabled */
 191                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 192                 goto end;
 193         }
 194
 195         ret = LTTNG_OK;
 196 end:
 197         return ret;
 198 }
 199
 200 /*
 201  * Enable all kernel tracepoint events of a channel of the kernel session.
 202  */
 203 int event_kernel_enable_all_tracepoints(struct ltt_kernel_channel *kchan,
 204                 int kernel_tracer_fd)
 205 {
 206         int size, i, ret;
 207         struct ltt_kernel_event *kevent;
 208         struct lttng_event *event_list = NULL;
 209
 210         assert(kchan);
 211
 212         /* For each event in the kernel session */
 213         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
 214                 if (kevent->enabled == 0) {
 215                         ret = kernel_enable_event(kevent);
 216                         if (ret < 0) {
 217                                 /* Enable failed but still continue */
 218                                 continue;
 219                         }
 220                 }
 221         }
 222
 223         size = kernel_list_events(kernel_tracer_fd, &event_list);
 224         if (size < 0) {
 225                 ret = LTTNG_ERR_KERN_LIST_FAIL;
 226                 goto end;
 227         }
 228
 229         for (i = 0; i < size; i++) {
 230                 kevent = trace_kernel_get_event_by_name(event_list[i].name, kchan);
 231                 if (kevent == NULL) {
 232                         /* Default event type for enable all */
 233                         event_list[i].type = LTTNG_EVENT_TRACEPOINT;
 234                         /* Enable each single tracepoint event */
 235                         ret = kernel_create_event(&event_list[i], kchan);
 236                         if (ret < 0) {
 237                                 /* Ignore error here and continue */
 238                         }
 239                 }
 240         }
 241         free(event_list);
 242
 243         ret = LTTNG_OK;
 244 end:
 245         return ret;
 246 }
 247
 248 /*
 249  * Enable all kernel sycalls events of a channel of the kernel session.
 250  */
 251 int event_kernel_enable_all_syscalls(struct ltt_kernel_channel *kchan,
 252                 int kernel_tracer_fd)
 253 {
 254         int ret;
 255         struct lttng_event event;
 256
 257         assert(kchan);
 258
 259         init_syscalls_kernel_event(&event);
 260
 261         DBG("Enabling all syscall tracing");
 262
 263         ret = kernel_create_event(&event, kchan);
 264         if (ret < 0) {
 265                 if (ret == -EEXIST) {
 266                         ret = LTTNG_ERR_KERN_EVENT_EXIST;
 267                 } else {
 268                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 269                 }
 270                 goto end;
 271         }
 272
 273         ret = LTTNG_OK;
 274 end:
 275         return ret;
 276 }
 277
 278 /*
 279  * Enable all kernel events of a channel of the kernel session.
 280  */
 281 int event_kernel_enable_all(struct ltt_kernel_channel *kchan,
 282                 int kernel_tracer_fd)
 283 {
 284         int tp_ret;
 285
 286         assert(kchan);
 287
 288         tp_ret = event_kernel_enable_all_tracepoints(kchan, kernel_tracer_fd);
 289         if (tp_ret != LTTNG_OK) {
 290                 goto end;
 291         }
 292
 293         /*
 294          * Reaching this code path means that all tracepoints were enabled without
 295          * errors so we ignore the error value of syscalls.
 296          *
 297          * At the moment, failing to enable syscalls on "lttng enable-event -a -k"
 298          * is not considered an error that need to be returned to the client since
 299          * tracepoints did not fail. Future work will allow us to send back
 300          * multiple errors to the client in one API call.
 301          */
 302         (void) event_kernel_enable_all_syscalls(kchan, kernel_tracer_fd);
 303
 304 end:
 305         return tp_ret;
 306 }
 307
 308 /*
 309  * ============================
 310  * UST : The Ultimate Frontier!
 311  * ============================
 312  */
 313
 314 /*
 315  * Enable all UST tracepoints for a channel from a UST session.
 316  */
 317 int event_ust_enable_all_tracepoints(struct ltt_ust_session *usess,
 318                 struct ltt_ust_channel *uchan,
 319                 char *filter_expression,
 320                 struct lttng_filter_bytecode *filter)
 321 {
 322         int ret, i, size;
 323         struct lttng_ht_iter iter;
 324         struct ltt_ust_event *uevent = NULL;
 325         struct lttng_event *events = NULL;
 326
 327         assert(usess);
 328         assert(uchan);
 329
 330         rcu_read_lock();
 331
 332         /* Enable existing events */
 333         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 334                         node.node) {
 335                 if (uevent->enabled == 0) {
 336                         ret = ust_app_enable_event_glb(usess, uchan, uevent);
 337                         if (ret < 0) {
 338                                 continue;
 339                         }
 340                         uevent->enabled = 1;
 341                 }
 342         }
 343
 344         /* Get all UST available events */
 345         size = ust_app_list_events(&events);
 346         if (size < 0) {
 347                 ret = LTTNG_ERR_UST_LIST_FAIL;
 348                 goto error;
 349         }
 350
 351         for (i = 0; i < size; i++) {
 352                 /*
 353                  * Check if event exist and if so, continue since it was enable
 354                  * previously.
 355                  */
 356                 uevent = trace_ust_find_event(uchan->events, events[i].name, filter,
 357                                 events[i].loglevel, NULL);
 358                 if (uevent != NULL) {
 359                         ret = ust_app_enable_event_pid(usess, uchan, uevent,
 360                                         events[i].pid);
 361                         if (ret < 0) {
 362                                 if (ret != -LTTNG_UST_ERR_EXIST) {
 363                                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 364                                         goto error;
 365                                 }
 366                         }
 367                         continue;
 368                 }
 369
 370                 /* Create ust event */
 371                 uevent = trace_ust_create_event(&events[i], filter_expression,
 372                         filter, NULL);
 373                 if (uevent == NULL) {
 374                         ret = LTTNG_ERR_FATAL;
 375                         goto error_destroy;
 376                 }
 377
 378                 /* Create event for the specific PID */
 379                 ret = ust_app_enable_event_pid(usess, uchan, uevent,
 380                                 events[i].pid);
 381                 if (ret < 0) {
 382                         if (ret == -LTTNG_UST_ERR_EXIST) {
 383                                 ret = LTTNG_ERR_UST_EVENT_EXIST;
 384                                 goto error;
 385                         } else {
 386                                 ret = LTTNG_ERR_UST_ENABLE_FAIL;
 387                                 goto error_destroy;
 388                         }
 389                 }
 390
 391                 uevent->enabled = 1;
 392                 /* Add ltt ust event to channel */
 393                 rcu_read_lock();
 394                 add_unique_ust_event(uchan->events, uevent);
 395                 rcu_read_unlock();
 396         }
 397         free(events);
 398
 399         rcu_read_unlock();
 400         return LTTNG_OK;
 401
 402 error_destroy:
 403         trace_ust_destroy_event(uevent);
 404
 405 error:
 406         free(events);
 407         rcu_read_unlock();
 408         return ret;
 409 }
 410
 411 /*
 412  * Enable UST tracepoint event for a channel from a UST session.
 413  */
 414 int event_ust_enable_tracepoint(struct ltt_ust_session *usess,
 415                 struct ltt_ust_channel *uchan, struct lttng_event *event,
 416                 char *filter_expression,
 417                 struct lttng_filter_bytecode *filter,
 418                 struct lttng_event_exclusion *exclusion)
 419 {
 420         int ret = LTTNG_OK, to_create = 0;
 421         struct ltt_ust_event *uevent;
 422
 423         assert(usess);
 424         assert(uchan);
 425         assert(event);
 426
 427         rcu_read_lock();
 428
 429         uevent = trace_ust_find_event(uchan->events, event->name, filter,
 430                         event->loglevel, exclusion);
 431         if (uevent == NULL) {
 432                 uevent = trace_ust_create_event(event, filter_expression,
 433                         filter, exclusion);
 434                 if (uevent == NULL) {
 435                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 436                         goto error;
 437                 }
 438
 439                 /* Valid to set it after the goto error since uevent is still NULL */
 440                 to_create = 1;
 441         }
 442
 443         if (uevent->enabled) {
 444                 /* It's already enabled so everything is OK */
 445                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 446                 goto end;
 447         }
 448
 449         uevent->enabled = 1;
 450
 451         if (to_create) {
 452                 /* Create event on all UST registered apps for session */
 453                 ret = ust_app_create_event_glb(usess, uchan, uevent);
 454         } else {
 455                 /* Enable event on all UST registered apps for session */
 456                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 457         }
 458
 459         if (ret < 0) {
 460                 if (ret == -LTTNG_UST_ERR_EXIST) {
 461                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 462                         goto end;
 463                 } else {
 464                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 465                         goto error;
 466                 }
 467         }
 468
 469         if (to_create) {
 470                 /* Add ltt ust event to channel */
 471                 add_unique_ust_event(uchan->events, uevent);
 472         }
 473
 474         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 475                         to_create ? "created" : "enabled", uchan->name);
 476
 477         ret = LTTNG_OK;
 478
 479 end:
 480         rcu_read_unlock();
 481         return ret;
 482
 483 error:
 484         /*
 485          * Only destroy event on creation time (not enabling time) because if the
 486          * event is found in the channel (to_create == 0), it means that at some
 487          * point the enable_event worked and it's thus valid to keep it alive.
 488          * Destroying it also implies that we also destroy it's shadow copy to sync
 489          * everyone up.
 490          */
 491         if (to_create) {
 492                 /* In this code path, the uevent was not added to the hash table */
 493                 trace_ust_destroy_event(uevent);
 494         }
 495         rcu_read_unlock();
 496         return ret;
 497 }
 498
 499 /*
 500  * Disable UST tracepoint of a channel from a UST session.
 501  */
 502 int event_ust_disable_tracepoint(struct ltt_ust_session *usess,
 503                 struct ltt_ust_channel *uchan, char *event_name)
 504 {
 505         int ret;
 506         struct ltt_ust_event *uevent;
 507         struct lttng_ht_node_str *node;
 508         struct lttng_ht_iter iter;
 509         struct lttng_ht *ht;
 510
 511         assert(usess);
 512         assert(uchan);
 513         assert(event_name);
 514
 515         ht = uchan->events;
 516
 517         rcu_read_lock();
 518
 519         /*
 520          * We use a custom lookup since we need the iterator for the next_duplicate
 521          * call in the do while loop below.
 522          */
 523         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) event_name, lttng_ht_seed),
 524                         trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 525         node = lttng_ht_iter_get_node_str(&iter);
 526         if (node == NULL) {
 527                 DBG2("Trace UST event NOT found by name %s", event_name);
 528                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 529                 goto error;
 530         }
 531
 532         do {
 533                 uevent = caa_container_of(node, struct ltt_ust_event, node);
 534                 assert(uevent);
 535
 536                 if (uevent->enabled == 0) {
 537                         /* It's already disabled so everything is OK */
 538                         goto next;
 539                 }
 540
 541                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 542                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 543                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 544                         goto error;
 545                 }
 546                 uevent->enabled = 0;
 547
 548                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 549                                 uchan->name);
 550
 551 next:
 552                 /* Get next duplicate event by name. */
 553                 cds_lfht_next_duplicate(ht->ht, trace_ust_ht_match_event_by_name,
 554                                 event_name, &iter.iter);
 555                 node = lttng_ht_iter_get_node_str(&iter);
 556         } while (node);
 557
 558         ret = LTTNG_OK;
 559
 560 error:
 561         rcu_read_unlock();
 562         return ret;
 563 }
 564
 565 /*
 566  * Disable all UST tracepoints for a channel from a UST session.
 567  */
 568 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess,
 569                 struct ltt_ust_channel *uchan)
 570 {
 571         int ret, i, size;
 572         struct lttng_ht_iter iter;
 573         struct ltt_ust_event *uevent = NULL;
 574         struct lttng_event *events = NULL;
 575
 576         assert(usess);
 577         assert(uchan);
 578
 579         rcu_read_lock();
 580
 581         /* Disabling existing events */
 582         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 583                         node.node) {
 584                 if (uevent->enabled == 1) {
 585                         ret = event_ust_disable_tracepoint(usess, uchan,
 586                                         uevent->attr.name);
 587                         if (ret < 0) {
 588                                 continue;
 589                         }
 590                 }
 591         }
 592
 593         /* Get all UST available events */
 594         size = ust_app_list_events(&events);
 595         if (size < 0) {
 596                 ret = LTTNG_ERR_UST_LIST_FAIL;
 597                 goto error;
 598         }
 599
 600         for (i = 0; i < size; i++) {
 601                 ret = event_ust_disable_tracepoint(usess, uchan,
 602                                 events[i].name);
 603                 if (ret != LTTNG_OK) {
 604                         /* Continue to disable the rest... */
 605                         continue;
 606                 }
 607         }
 608         free(events);
 609
 610         rcu_read_unlock();
 611         return LTTNG_OK;
 612
 613 error:
 614         free(events);
 615         rcu_read_unlock();
 616         return ret;
 617 }
 618
 619 /*
 620  * Enable all agent event for a given UST session.
 621  *
 622  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 623  */
 624 int event_agent_enable_all(struct ltt_ust_session *usess,
 625                 struct lttng_event *event, struct lttng_filter_bytecode *filter)
 626 {
 627         int ret;
 628         struct agent_event *jevent;
 629         struct lttng_ht_iter iter;
 630
 631         assert(usess);
 632
 633         DBG("Event agent enabling ALL events for session %" PRIu64, usess->id);
 634
 635         /* Enable event on agent application through TCP socket. */
 636         ret = event_agent_enable(usess, event, filter);
 637         if (ret != LTTNG_OK) {
 638                 goto error;
 639         }
 640
 641         /* Flag every event that they are now enabled. */
 642         rcu_read_lock();
 643         cds_lfht_for_each_entry(usess->agent.events->ht, &iter.iter, jevent,
 644                         node.node) {
 645                 jevent->enabled = 1;
 646         }
 647         rcu_read_unlock();
 648
 649         ret = LTTNG_OK;
 650
 651 error:
 652         return ret;
 653 }
 654
 655 /*
 656  * Enable a single agent event for a given UST session.
 657  *
 658  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 659  */
 660 int event_agent_enable(struct ltt_ust_session *usess, struct lttng_event *event,
 661                 struct lttng_filter_bytecode *filter)
 662 {
 663         int ret, created = 0;
 664         struct agent_event *jevent;
 665
 666         assert(usess);
 667         assert(event);
 668
 669         DBG("Event agent enabling %s for session %" PRIu64 " with loglevel type %d "
 670                         "and loglevel %d", event->name, usess->id, event->loglevel_type,
 671                         event->loglevel);
 672
 673         jevent = agent_find_event(event->name, event->loglevel, &usess->agent);
 674         if (!jevent) {
 675                 jevent = agent_create_event(event->name, filter);
 676                 if (!jevent) {
 677                         ret = LTTNG_ERR_NOMEM;
 678                         goto error;
 679                 }
 680                 jevent->loglevel = event->loglevel;
 681                 jevent->loglevel_type = event->loglevel_type;
 682                 created = 1;
 683         }
 684
 685         /* Already enabled? */
 686         if (jevent->enabled) {
 687                 goto end;
 688         }
 689
 690         ret = agent_enable_event(jevent);
 691         if (ret != LTTNG_OK) {
 692                 goto error;
 693         }
 694
 695         /* If the event was created prior to the enable, add it to the domain. */
 696         if (created) {
 697                 agent_add_event(jevent, &usess->agent);
 698         }
 699
 700 end:
 701         return LTTNG_OK;
 702
 703 error:
 704         if (created) {
 705                 agent_destroy_event(jevent);
 706         }
 707         return ret;
 708 }
 709
 710 /*
 711  * Disable a single agent event for a given UST session.
 712  *
 713  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 714  */
 715 int event_agent_disable(struct ltt_ust_session *usess, char *event_name)
 716 {
 717         int ret;
 718         struct agent_event *jevent;
 719         struct ltt_ust_event *uevent = NULL;
 720         struct ltt_ust_channel *uchan = NULL;
 721         char *ust_event_name;
 722
 723         assert(usess);
 724         assert(event_name);
 725
 726         DBG("Event agent disabling %s for session %" PRIu64, event_name, usess->id);
 727
 728         jevent = agent_find_event_by_name(event_name, &usess->agent);
 729         if (!jevent) {
 730                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 731                 goto error;
 732         }
 733
 734         /* Already disabled? */
 735         if (!jevent->enabled) {
 736                 goto end;
 737         }
 738
 739         /*
 740          * Disable it on the UST side. First get the channel reference then find
 741          * the event and finally disable it.
 742          */
 743         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 744                         DEFAULT_JUL_CHANNEL_NAME);
 745         if (!uchan) {
 746                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 747                 goto error;
 748         }
 749
 750         if (is_root) {
 751                 ust_event_name = DEFAULT_SYS_JUL_EVENT_NAME;
 752         } else {
 753                 ust_event_name = DEFAULT_USER_JUL_EVENT_NAME;
 754         }
 755
 756         /*
 757          * The loglevel is hardcoded with 0 here since the agent ust event is set
 758          * with the loglevel type to ALL thus the loglevel stays 0. The event's
 759          * filter is the one handling the loglevel for agent.
 760          */
 761         uevent = trace_ust_find_event(uchan->events, ust_event_name,
 762                         jevent->filter, 0, NULL);
 763         /* If the agent event exists, it must be available on the UST side. */
 764         assert(uevent);
 765
 766         ret = ust_app_disable_event_glb(usess, uchan, uevent);
 767         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 768                 ret = LTTNG_ERR_UST_DISABLE_FAIL;
 769                 goto error;
 770         }
 771
 772         ret = agent_disable_event(jevent);
 773         if (ret != LTTNG_OK) {
 774                 goto error;
 775         }
 776
 777 end:
 778         return LTTNG_OK;
 779
 780 error:
 781         return ret;
 782 }
 783 /*
 784  * Disable all agent event for a given UST session.
 785  *
 786  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 787  */
 788 int event_agent_disable_all(struct ltt_ust_session *usess)
 789 {
 790         int ret, do_disable = 0;
 791         struct agent_event *jevent;
 792         struct lttng_ht_iter iter;
 793
 794         assert(usess);
 795
 796         /* Enable event on agent application through TCP socket. */
 797         ret = event_agent_disable(usess, "*");
 798         if (ret != LTTNG_OK) {
 799                 if (ret == LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 800                         /*
 801                          * This means that no enable all was done before but still a user
 802                          * could want to disable everything even though the * wild card
 803                          * event does not exists.
 804                          */
 805                         do_disable = 1;
 806                 } else {
 807                         goto error;
 808                 }
 809         }
 810
 811         /* Flag every event that they are now enabled. */
 812         rcu_read_lock();
 813         cds_lfht_for_each_entry(usess->agent.events->ht, &iter.iter, jevent,
 814                         node.node) {
 815                 if (jevent->enabled && do_disable) {
 816                         ret = event_agent_disable(usess, jevent->name);
 817                         if (ret != LTTNG_OK) {
 818                                 rcu_read_unlock();
 819                                 goto error;
 820                         }
 821                 }
 822                 jevent->enabled = 0;
 823         }
 824         rcu_read_unlock();
 825
 826         ret = LTTNG_OK;
 827
 828 error:
 829         return ret;
 830 }