src/bin/lttng-sessiond/jul.c

   1 /*
   2  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <assert.h>
  20 #include <urcu/uatomic.h>
  21
  22 #include <common/common.h>
  23 #include <common/sessiond-comm/jul.h>
  24
  25 #include "jul.h"
  26 #include "ust-app.h"
  27 #include "utils.h"
  28
  29 /*
  30  * URCU delayed JUL event reclaim.
  31  */
  32 static void destroy_event_jul_rcu(struct rcu_head *head)
  33 {
  34         struct lttng_ht_node_str *node =
  35                 caa_container_of(head, struct lttng_ht_node_str, head);
  36         struct jul_event *event =
  37                 caa_container_of(node, struct jul_event, node);
  38
  39         free(event);
  40 }
  41
  42 /*
  43  * URCU delayed JUL app reclaim.
  44  */
  45 static void destroy_app_jul_rcu(struct rcu_head *head)
  46 {
  47         struct lttng_ht_node_ulong *node =
  48                 caa_container_of(head, struct lttng_ht_node_ulong, head);
  49         struct jul_app *app =
  50                 caa_container_of(node, struct jul_app, node);
  51
  52         free(app);
  53 }
  54
  55 /*
  56  * Communication with Java agent. Send the message header to the given
  57  * socket in big endian.
  58  *
  59  * Return 0 on success or else a negative errno message of sendmsg() op.
  60  */
  61 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
  62                 uint32_t cmd, uint32_t cmd_version)
  63 {
  64         int ret;
  65         ssize_t size;
  66         struct lttcomm_jul_hdr msg;
  67
  68         assert(sock);
  69
  70         memset(&msg, 0, sizeof(msg));
  71         msg.data_size = htobe64(data_size);
  72         msg.cmd = htobe32(cmd);
  73         msg.cmd_version = htobe32(cmd_version);
  74
  75         size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
  76         if (size < sizeof(msg)) {
  77                 ret = -errno;
  78                 goto error;
  79         }
  80         ret = 0;
  81
  82 error:
  83         return ret;
  84 }
  85
  86 /*
  87  * Communication call with the Java agent. Send the payload to the given
  88  * socket. The header MUST be sent prior to this call.
  89  *
  90  * Return 0 on success or else a negative errno value of sendmsg() op.
  91  */
  92 static int send_payload(struct lttcomm_sock *sock, void *data,
  93                 size_t size)
  94 {
  95         int ret;
  96         ssize_t len;
  97
  98         assert(sock);
  99         assert(data);
 100
 101         len = sock->ops->sendmsg(sock, data, size, 0);
 102         if (len < size) {
 103                 ret = -errno;
 104                 goto error;
 105         }
 106         ret = 0;
 107
 108 error:
 109         return ret;
 110 }
 111
 112 /*
 113  * Communication call with the Java agent. Receive reply from the agent using
 114  * the given socket.
 115  *
 116  * Return 0 on success or else a negative errno value from recvmsg() op.
 117  */
 118 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
 119 {
 120         int ret;
 121         ssize_t len;
 122
 123         assert(sock);
 124         assert(buf);
 125
 126         len = sock->ops->recvmsg(sock, buf, size, 0);
 127         if (len < size) {
 128                 ret = -errno;
 129                 goto error;
 130         }
 131         ret = 0;
 132
 133 error:
 134         return ret;
 135 }
 136
 137
 138 /*
 139  * Internal event listing for a given app. Populate events.
 140  *
 141  * Return number of element in the list or else a negative LTTNG_ERR* code.
 142  * On success, the caller is responsible for freeing the memory
 143  * allocated for "events".
 144  */
 145 static ssize_t list_events(struct jul_app *app, struct lttng_event **events)
 146 {
 147         int ret, i, len = 0, offset = 0;
 148         uint32_t nb_event;
 149         size_t data_size;
 150         struct lttng_event *tmp_events = NULL;
 151         struct lttcomm_jul_list_reply *reply = NULL;
 152         struct lttcomm_jul_list_reply_hdr reply_hdr;
 153
 154         assert(app);
 155         assert(app->sock);
 156         assert(events);
 157
 158         DBG2("JUL listing events for app pid: %d and socket %d", app->pid,
 159                         app->sock->fd);
 160
 161         ret = send_header(app->sock, 0, JUL_CMD_LIST, 0);
 162         if (ret < 0) {
 163                 goto error_io;
 164         }
 165
 166         /* Get list header so we know how much we'll receive. */
 167         ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
 168         if (ret < 0) {
 169                 goto error_io;
 170         }
 171
 172         switch (be32toh(reply_hdr.ret_code)) {
 173         case JUL_RET_CODE_SUCCESS:
 174                 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
 175                 break;
 176         default:
 177                 ERR("Java agent returned an unknown code: %" PRIu32,
 178                                 be32toh(reply_hdr.ret_code));
 179                 ret = LTTNG_ERR_FATAL;
 180                 goto error;
 181         }
 182
 183         reply = zmalloc(data_size);
 184         if (!reply) {
 185                 ret = LTTNG_ERR_NOMEM;
 186                 goto error;
 187         }
 188
 189         /* Get the list with the appropriate data size. */
 190         ret = recv_reply(app->sock, reply, data_size);
 191         if (ret < 0) {
 192                 goto error_io;
 193         }
 194
 195         nb_event = be32toh(reply->nb_event);
 196         tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
 197         if (!tmp_events) {
 198                 ret = LTTNG_ERR_NOMEM;
 199                 goto error;
 200         }
 201
 202         for (i = 0; i < nb_event; i++) {
 203                 offset += len;
 204                 strncpy(tmp_events[i].name, reply->payload + offset,
 205                                 sizeof(tmp_events[i].name));
 206                 tmp_events[i].pid = app->pid;
 207                 tmp_events[i].enabled = -1;
 208                 len = strlen(reply->payload + offset) + 1;
 209         }
 210
 211         *events = tmp_events;
 212
 213         free(reply);
 214         return nb_event;
 215
 216 error_io:
 217         ret = LTTNG_ERR_UST_LIST_FAIL;
 218 error:
 219         free(reply);
 220         free(tmp_events);
 221         return -ret;
 222
 223 }
 224
 225 /*
 226  * Internal enable JUL event on a JUL application. This function
 227  * communicates with the Java agent to enable a given event (Logger name).
 228  *
 229  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 230  */
 231 static int enable_event(struct jul_app *app, struct jul_event *event)
 232 {
 233         int ret;
 234         uint64_t data_size;
 235         struct lttcomm_jul_enable msg;
 236         struct lttcomm_jul_generic_reply reply;
 237
 238         assert(app);
 239         assert(app->sock);
 240         assert(event);
 241
 242         DBG2("JUL enabling event %s for app pid: %d and socket %d", event->name,
 243                         app->pid, app->sock->fd);
 244
 245         data_size = sizeof(msg);
 246
 247         ret = send_header(app->sock, data_size, JUL_CMD_ENABLE, 0);
 248         if (ret < 0) {
 249                 goto error_io;
 250         }
 251
 252         memset(&msg, 0, sizeof(msg));
 253         msg.loglevel = event->loglevel;
 254         msg.loglevel_type = event->loglevel_type;
 255         strncpy(msg.name, event->name, sizeof(msg.name));
 256         ret = send_payload(app->sock, &msg, sizeof(msg));
 257         if (ret < 0) {
 258                 goto error_io;
 259         }
 260
 261         ret = recv_reply(app->sock, &reply, sizeof(reply));
 262         if (ret < 0) {
 263                 goto error_io;
 264         }
 265
 266         switch (be32toh(reply.ret_code)) {
 267         case JUL_RET_CODE_SUCCESS:
 268                 break;
 269         case JUL_RET_CODE_UNKNOWN_NAME:
 270                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 271                 goto error;
 272         default:
 273                 ERR("Java agent returned an unknown code: %" PRIu32,
 274                                 be32toh(reply.ret_code));
 275                 ret = LTTNG_ERR_FATAL;
 276                 goto error;
 277         }
 278
 279         return LTTNG_OK;
 280
 281 error_io:
 282         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 283 error:
 284         return ret;
 285 }
 286
 287 /*
 288  * Internal disable JUL event call on a JUL application. This function
 289  * communicates with the Java agent to disable a given event (Logger name).
 290  *
 291  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 292  */
 293 static int disable_event(struct jul_app *app, struct jul_event *event)
 294 {
 295         int ret;
 296         uint64_t data_size;
 297         struct lttcomm_jul_disable msg;
 298         struct lttcomm_jul_generic_reply reply;
 299
 300         assert(app);
 301         assert(app->sock);
 302         assert(event);
 303
 304         DBG2("JUL disabling event %s for app pid: %d and socket %d", event->name,
 305                         app->pid, app->sock->fd);
 306
 307         data_size = sizeof(msg);
 308
 309         ret = send_header(app->sock, data_size, JUL_CMD_DISABLE, 0);
 310         if (ret < 0) {
 311                 goto error_io;
 312         }
 313
 314         memset(&msg, 0, sizeof(msg));
 315         strncpy(msg.name, event->name, sizeof(msg.name));
 316         ret = send_payload(app->sock, &msg, sizeof(msg));
 317         if (ret < 0) {
 318                 goto error_io;
 319         }
 320
 321         ret = recv_reply(app->sock, &reply, sizeof(reply));
 322         if (ret < 0) {
 323                 goto error_io;
 324         }
 325
 326         switch (be32toh(reply.ret_code)) {
 327                 case JUL_RET_CODE_SUCCESS:
 328                         break;
 329                 case JUL_RET_CODE_UNKNOWN_NAME:
 330                         ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 331                         goto error;
 332                 default:
 333                         ERR("Java agent returned an unknown code: %" PRIu32,
 334                                         be32toh(reply.ret_code));
 335                         ret = LTTNG_ERR_FATAL;
 336                         goto error;
 337         }
 338
 339         return LTTNG_OK;
 340
 341 error_io:
 342         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 343 error:
 344         return ret;
 345 }
 346
 347 /*
 348  * Send back the registration DONE command to a given JUL application.
 349  *
 350  * Return 0 on success or else a negative value.
 351  */
 352 int jul_send_registration_done(struct jul_app *app)
 353 {
 354         assert(app);
 355         assert(app->sock);
 356
 357         DBG("JUL sending registration done to app socket %d", app->sock->fd);
 358
 359         return send_header(app->sock, 0, JUL_CMD_REG_DONE, 0);
 360 }
 361
 362 /*
 363  * Enable JUL event on every JUL applications registered with the session
 364  * daemon.
 365  *
 366  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 367  */
 368 int jul_enable_event(struct jul_event *event)
 369 {
 370         int ret;
 371         struct jul_app *app;
 372         struct lttng_ht_iter iter;
 373
 374         assert(event);
 375
 376         rcu_read_lock();
 377
 378         cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, app,
 379                         node.node) {
 380                 /* Enable event on JUL application through TCP socket. */
 381                 ret = enable_event(app, event);
 382                 if (ret != LTTNG_OK) {
 383                         goto error;
 384                 }
 385         }
 386
 387         event->enabled = 1;
 388         ret = LTTNG_OK;
 389
 390 error:
 391         rcu_read_unlock();
 392         return ret;
 393 }
 394
 395 /*
 396  * Disable JUL event on every JUL applications registered with the session
 397  * daemon.
 398  *
 399  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 400  */
 401 int jul_disable_event(struct jul_event *event)
 402 {
 403         int ret;
 404         struct jul_app *app;
 405         struct lttng_ht_iter iter;
 406
 407         assert(event);
 408
 409         rcu_read_lock();
 410
 411         cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, app,
 412                         node.node) {
 413                 /* Enable event on JUL application through TCP socket. */
 414                 ret = disable_event(app, event);
 415                 if (ret != LTTNG_OK) {
 416                         goto error;
 417                 }
 418         }
 419
 420         event->enabled = 0;
 421         ret = LTTNG_OK;
 422
 423 error:
 424         rcu_read_unlock();
 425         return ret;
 426 }
 427
 428 /*
 429  * Ask every java agent for the list of possible event (logger name). Events is
 430  * allocated with the events of every JUL application.
 431  *
 432  * Return the number of events or else a negative value.
 433  */
 434 int jul_list_events(struct lttng_event **events)
 435 {
 436         int ret;
 437         size_t nbmem, count = 0;
 438         struct jul_app *app;
 439         struct lttng_event *tmp_events = NULL;
 440         struct lttng_ht_iter iter;
 441
 442         assert(events);
 443
 444         nbmem = UST_APP_EVENT_LIST_SIZE;
 445         tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
 446         if (!tmp_events) {
 447                 PERROR("zmalloc jul list events");
 448                 ret = -ENOMEM;
 449                 goto error;
 450         }
 451
 452         rcu_read_lock();
 453         cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, app,
 454                         node.node) {
 455                 ssize_t nb_ev;
 456                 struct lttng_event *jul_events;
 457
 458                 nb_ev = list_events(app, &jul_events);
 459                 if (nb_ev < 0) {
 460                         ret = nb_ev;
 461                         goto error_unlock;
 462                 }
 463
 464                 if (count + nb_ev > nbmem) {
 465                         /* In case the realloc fails, we free the memory */
 466                         struct lttng_event *new_tmp_events;
 467                         size_t new_nbmem;
 468
 469                         new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
 470                         DBG2("Reallocating JUL event list from %zu to %zu entries",
 471                                         nbmem, new_nbmem);
 472                         new_tmp_events = realloc(tmp_events,
 473                                 new_nbmem * sizeof(*new_tmp_events));
 474                         if (!new_tmp_events) {
 475                                 PERROR("realloc JUL events");
 476                                 ret = -ENOMEM;
 477                                 free(jul_events);
 478                                 goto error_unlock;
 479                         }
 480                         /* Zero the new memory */
 481                         memset(new_tmp_events + nbmem, 0,
 482                                 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
 483                         nbmem = new_nbmem;
 484                         tmp_events = new_tmp_events;
 485                 }
 486                 memcpy(tmp_events + count, jul_events,
 487                         nb_ev * sizeof(*tmp_events));
 488                 free(jul_events);
 489                 count += nb_ev;
 490         }
 491         rcu_read_unlock();
 492
 493         ret = count;
 494         *events = tmp_events;
 495         return ret;
 496
 497 error_unlock:
 498         rcu_read_unlock();
 499 error:
 500         free(tmp_events);
 501         return ret;
 502 }
 503
 504 /*
 505  * Create a JUL app object using the given PID.
 506  *
 507  * Return newly allocated object or else NULL on error.
 508  */
 509 struct jul_app *jul_create_app(pid_t pid, struct lttcomm_sock *sock)
 510 {
 511         struct jul_app *app;
 512
 513         assert(sock);
 514
 515         app = zmalloc(sizeof(*app));
 516         if (!app) {
 517                 PERROR("zmalloc JUL create");
 518                 goto error;
 519         }
 520
 521         app->pid = pid;
 522         app->sock = sock;
 523         lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
 524
 525 error:
 526         return app;
 527 }
 528
 529 /*
 530  * Lookup JUL app by socket in the global hash table.
 531  *
 532  * RCU read side lock MUST be acquired.
 533  *
 534  * Return object if found else NULL.
 535  */
 536 struct jul_app *jul_find_app_by_sock(int sock)
 537 {
 538         struct lttng_ht_node_ulong *node;
 539         struct lttng_ht_iter iter;
 540         struct jul_app *app;
 541
 542         assert(sock >= 0);
 543
 544         lttng_ht_lookup(jul_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
 545         node = lttng_ht_iter_get_node_ulong(&iter);
 546         if (node == NULL) {
 547                 goto error;
 548         }
 549         app = caa_container_of(node, struct jul_app, node);
 550
 551         DBG3("JUL app pid %d found by sock %d.", app->pid, sock);
 552         return app;
 553
 554 error:
 555         DBG3("JUL app NOT found by sock %d.", sock);
 556         return NULL;
 557 }
 558
 559 /*
 560  * Add JUL application object to a given hash table.
 561  */
 562 void jul_add_app(struct jul_app *app)
 563 {
 564         assert(app);
 565
 566         DBG3("JUL adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
 567
 568         rcu_read_lock();
 569         lttng_ht_add_unique_ulong(jul_apps_ht_by_sock, &app->node);
 570         rcu_read_unlock();
 571 }
 572
 573 /*
 574  * Delete JUL application from the global hash table.
 575  */
 576 void jul_delete_app(struct jul_app *app)
 577 {
 578         int ret;
 579         struct lttng_ht_iter iter;
 580
 581         assert(app);
 582
 583         DBG3("JUL deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
 584
 585         iter.iter.node = &app->node.node;
 586         rcu_read_lock();
 587         ret = lttng_ht_del(jul_apps_ht_by_sock, &iter);
 588         rcu_read_unlock();
 589         assert(!ret);
 590 }
 591
 592 /*
 593  * Destroy a JUL application object by detaching it from its corresponding UST
 594  * app if one is connected by closing the socket. Finally, perform a
 595  * delayed memory reclaim.
 596  */
 597 void jul_destroy_app(struct jul_app *app)
 598 {
 599         assert(app);
 600
 601         if (app->sock) {
 602                 app->sock->ops->close(app->sock);
 603                 lttcomm_destroy_sock(app->sock);
 604         }
 605
 606         call_rcu(&app->node.head, destroy_app_jul_rcu);
 607 }
 608
 609 /*
 610  * Initialize an already allocated JUL domain object.
 611  *
 612  * Return 0 on success or else a negative errno value.
 613  */
 614 int jul_init_domain(struct jul_domain *dom)
 615 {
 616         int ret;
 617
 618         assert(dom);
 619
 620         dom->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 621         if (!dom->events) {
 622                 ret = -ENOMEM;
 623                 goto error;
 624         }
 625
 626         return 0;
 627
 628 error:
 629         return ret;
 630 }
 631
 632 /*
 633  * Create a newly allocated JUL event data structure. If name is valid, it's
 634  * copied into the created event.
 635  *
 636  * Return a new object else NULL on error.
 637  */
 638 struct jul_event *jul_create_event(const char *name)
 639 {
 640         struct jul_event *event;
 641
 642         DBG3("JUL create new event with name %s", name);
 643
 644         event = zmalloc(sizeof(*event));
 645         if (!event) {
 646                 goto error;
 647         }
 648
 649         if (name) {
 650                 strncpy(event->name, name, sizeof(event->name));
 651                 event->name[sizeof(event->name) - 1] = '\0';
 652                 lttng_ht_node_init_str(&event->node, event->name);
 653         }
 654
 655 error:
 656         return event;
 657 }
 658
 659 /*
 660  * Unique add of a JUL event to a given domain.
 661  */
 662 void jul_add_event(struct jul_event *event, struct jul_domain *dom)
 663 {
 664         assert(event);
 665         assert(dom);
 666         assert(dom->events);
 667
 668         DBG3("JUL adding event %s to domain", event->name);
 669
 670         rcu_read_lock();
 671         lttng_ht_add_unique_str(dom->events, &event->node);
 672         rcu_read_unlock();
 673         dom->being_used = 1;
 674 }
 675
 676 /*
 677  * Find a JUL event in the given domain using name.
 678  *
 679  * RCU read side lock MUST be acquired.
 680  *
 681  * Return object if found else NULL.
 682  */
 683 struct jul_event *jul_find_by_name(const char *name, struct jul_domain *dom)
 684 {
 685         struct lttng_ht_node_str *node;
 686         struct lttng_ht_iter iter;
 687
 688         assert(name);
 689         assert(dom);
 690         assert(dom->events);
 691
 692         lttng_ht_lookup(dom->events, (void *)name, &iter);
 693         node = lttng_ht_iter_get_node_str(&iter);
 694         if (node == NULL) {
 695                 goto error;
 696         }
 697
 698         DBG3("JUL found by name %s in domain.", name);
 699         return caa_container_of(node, struct jul_event, node);
 700
 701 error:
 702         DBG3("JUL NOT found by name %s in domain.", name);
 703         return NULL;
 704 }
 705
 706 /*
 707  * Free given JUL event. This event must not be globally visible at this
 708  * point (only expected to be used on failure just after event
 709  * creation). After this call, the pointer is not usable anymore.
 710  */
 711 void jul_destroy_event(struct jul_event *event)
 712 {
 713         assert(event);
 714
 715         free(event);
 716 }
 717
 718 /*
 719  * Destroy a JUL domain completely. Note that the given pointer is NOT freed
 720  * thus a reference to static or stack data can be passed to this function.
 721  */
 722 void jul_destroy_domain(struct jul_domain *dom)
 723 {
 724         struct lttng_ht_node_str *node;
 725         struct lttng_ht_iter iter;
 726
 727         assert(dom);
 728
 729         DBG3("JUL destroy domain");
 730
 731         /*
 732          * Just ignore if no events hash table exists. This is possible if for
 733          * instance a JUL domain object was allocated but not initialized.
 734          */
 735         if (!dom->events) {
 736                 return;
 737         }
 738
 739         rcu_read_lock();
 740         cds_lfht_for_each_entry(dom->events->ht, &iter.iter, node, node) {
 741                 int ret;
 742
 743                 ret = lttng_ht_del(dom->events, &iter);
 744                 assert(!ret);
 745                 call_rcu(&node->head, destroy_event_jul_rcu);
 746         }
 747         rcu_read_unlock();
 748
 749         lttng_ht_destroy(dom->events);
 750 }
 751
 752 /*
 753  * Initialize JUL subsystem.
 754  */
 755 int jul_init(void)
 756 {
 757         jul_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 758         if (!jul_apps_ht_by_sock) {
 759                 return -1;
 760         }
 761
 762         return 0;
 763 }
 764
 765 /*
 766  * Update a JUL application (given socket) using the given domain.
 767  *
 768  * Note that this function is most likely to be used with a tracing session
 769  * thus the caller should make sure to hold the appropriate lock(s).
 770  */
 771 void jul_update(struct jul_domain *domain, int sock)
 772 {
 773         int ret;
 774         struct jul_app *app;
 775         struct jul_event *event;
 776         struct lttng_ht_iter iter;
 777
 778         assert(domain);
 779         assert(sock >= 0);
 780
 781         DBG("JUL updating app socket %d", sock);
 782
 783         rcu_read_lock();
 784         cds_lfht_for_each_entry(domain->events->ht, &iter.iter, event, node.node) {
 785                 /* Skip event if disabled. */
 786                 if (!event->enabled) {
 787                         continue;
 788                 }
 789
 790                 app = jul_find_app_by_sock(sock);
 791                 /*
 792                  * We are in the registration path thus if the application is gone,
 793                  * there is a serious code flow error.
 794                  */
 795                 assert(app);
 796
 797                 ret = enable_event(app, event);
 798                 if (ret != LTTNG_OK) {
 799                         DBG2("JUL update unable to enable event %s on app pid: %d sock %d",
 800                                         event->name, app->pid, app->sock->fd);
 801                         /* Let's try the others here and don't assume the app is dead. */
 802                         continue;
 803                 }
 804         }
 805         rcu_read_unlock();
 806 }