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