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  * Match function for the events hash table lookup by name.
  31  */
  32 static int ht_match_event_by_name(struct cds_lfht_node *node,
  33                 const void *_key)
  34 {
  35         struct jul_event *event;
  36         const struct jul_ht_key *key;
  37
  38         assert(node);
  39         assert(_key);
  40
  41         event = caa_container_of(node, struct jul_event, node.node);
  42         key = _key;
  43
  44         /* Match 1 elements of the key: name. */
  45
  46         /* Event name */
  47         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  48                 goto no_match;
  49         }
  50         /* Match. */
  51         return 1;
  52
  53 no_match:
  54         return 0;
  55 }
  56
  57 /*
  58  * Match function for the events hash table lookup by name and loglevel.
  59  */
  60 static int ht_match_event(struct cds_lfht_node *node,
  61                 const void *_key)
  62 {
  63         struct jul_event *event;
  64         const struct jul_ht_key *key;
  65
  66         assert(node);
  67         assert(_key);
  68
  69         event = caa_container_of(node, struct jul_event, node.node);
  70         key = _key;
  71
  72         /* Match 2 elements of the key: name and loglevel. */
  73
  74         /* Event name */
  75         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  76                 goto no_match;
  77         }
  78
  79         if (event->loglevel != key->loglevel) {
  80                 if (event->loglevel_type == LTTNG_EVENT_LOGLEVEL_ALL &&
  81                                 key->loglevel == 0 && event->loglevel == -1) {
  82                         goto match;
  83                 }
  84                 goto no_match;
  85         }
  86 match:
  87         return 1;
  88
  89 no_match:
  90         return 0;
  91 }
  92
  93 /*
  94  * Add unique JUL event based on the event name and loglevel.
  95  */
  96 static void add_unique_jul_event(struct lttng_ht *ht, struct jul_event *event)
  97 {
  98         struct cds_lfht_node *node_ptr;
  99         struct jul_ht_key key;
 100
 101         assert(ht);
 102         assert(ht->ht);
 103         assert(event);
 104
 105         key.name = event->name;
 106         key.loglevel = event->loglevel;
 107
 108         node_ptr = cds_lfht_add_unique(ht->ht,
 109                         ht->hash_fct(event->node.key, lttng_ht_seed),
 110                         ht_match_event, &key, &event->node.node);
 111         assert(node_ptr == &event->node.node);
 112 }
 113
 114 /*
 115  * URCU delayed JUL event reclaim.
 116  */
 117 static void destroy_event_jul_rcu(struct rcu_head *head)
 118 {
 119         struct lttng_ht_node_str *node =
 120                 caa_container_of(head, struct lttng_ht_node_str, head);
 121         struct jul_event *event =
 122                 caa_container_of(node, struct jul_event, node);
 123
 124         free(event);
 125 }
 126
 127 /*
 128  * URCU delayed JUL app reclaim.
 129  */
 130 static void destroy_app_jul_rcu(struct rcu_head *head)
 131 {
 132         struct lttng_ht_node_ulong *node =
 133                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 134         struct jul_app *app =
 135                 caa_container_of(node, struct jul_app, node);
 136
 137         free(app);
 138 }
 139
 140 /*
 141  * Communication with Java agent. Send the message header to the given
 142  * socket in big endian.
 143  *
 144  * Return 0 on success or else a negative errno message of sendmsg() op.
 145  */
 146 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
 147                 uint32_t cmd, uint32_t cmd_version)
 148 {
 149         int ret;
 150         ssize_t size;
 151         struct lttcomm_jul_hdr msg;
 152
 153         assert(sock);
 154
 155         memset(&msg, 0, sizeof(msg));
 156         msg.data_size = htobe64(data_size);
 157         msg.cmd = htobe32(cmd);
 158         msg.cmd_version = htobe32(cmd_version);
 159
 160         size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
 161         if (size < sizeof(msg)) {
 162                 ret = -errno;
 163                 goto error;
 164         }
 165         ret = 0;
 166
 167 error:
 168         return ret;
 169 }
 170
 171 /*
 172  * Communication call with the Java agent. Send the payload to the given
 173  * socket. The header MUST be sent prior to this call.
 174  *
 175  * Return 0 on success or else a negative errno value of sendmsg() op.
 176  */
 177 static int send_payload(struct lttcomm_sock *sock, void *data,
 178                 size_t size)
 179 {
 180         int ret;
 181         ssize_t len;
 182
 183         assert(sock);
 184         assert(data);
 185
 186         len = sock->ops->sendmsg(sock, data, size, 0);
 187         if (len < size) {
 188                 ret = -errno;
 189                 goto error;
 190         }
 191         ret = 0;
 192
 193 error:
 194         return ret;
 195 }
 196
 197 /*
 198  * Communication call with the Java agent. Receive reply from the agent using
 199  * the given socket.
 200  *
 201  * Return 0 on success or else a negative errno value from recvmsg() op.
 202  */
 203 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
 204 {
 205         int ret;
 206         ssize_t len;
 207
 208         assert(sock);
 209         assert(buf);
 210
 211         len = sock->ops->recvmsg(sock, buf, size, 0);
 212         if (len < size) {
 213                 ret = -errno;
 214                 goto error;
 215         }
 216         ret = 0;
 217
 218 error:
 219         return ret;
 220 }
 221
 222
 223 /*
 224  * Internal event listing for a given app. Populate events.
 225  *
 226  * Return number of element in the list or else a negative LTTNG_ERR* code.
 227  * On success, the caller is responsible for freeing the memory
 228  * allocated for "events".
 229  */
 230 static ssize_t list_events(struct jul_app *app, struct lttng_event **events)
 231 {
 232         int ret, i, len = 0, offset = 0;
 233         uint32_t nb_event;
 234         size_t data_size;
 235         struct lttng_event *tmp_events = NULL;
 236         struct lttcomm_jul_list_reply *reply = NULL;
 237         struct lttcomm_jul_list_reply_hdr reply_hdr;
 238
 239         assert(app);
 240         assert(app->sock);
 241         assert(events);
 242
 243         DBG2("JUL listing events for app pid: %d and socket %d", app->pid,
 244                         app->sock->fd);
 245
 246         ret = send_header(app->sock, 0, JUL_CMD_LIST, 0);
 247         if (ret < 0) {
 248                 goto error_io;
 249         }
 250
 251         /* Get list header so we know how much we'll receive. */
 252         ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
 253         if (ret < 0) {
 254                 goto error_io;
 255         }
 256
 257         switch (be32toh(reply_hdr.ret_code)) {
 258         case JUL_RET_CODE_SUCCESS:
 259                 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
 260                 break;
 261         default:
 262                 ERR("Java agent returned an unknown code: %" PRIu32,
 263                                 be32toh(reply_hdr.ret_code));
 264                 ret = LTTNG_ERR_FATAL;
 265                 goto error;
 266         }
 267
 268         reply = zmalloc(data_size);
 269         if (!reply) {
 270                 ret = LTTNG_ERR_NOMEM;
 271                 goto error;
 272         }
 273
 274         /* Get the list with the appropriate data size. */
 275         ret = recv_reply(app->sock, reply, data_size);
 276         if (ret < 0) {
 277                 goto error_io;
 278         }
 279
 280         nb_event = be32toh(reply->nb_event);
 281         tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
 282         if (!tmp_events) {
 283                 ret = LTTNG_ERR_NOMEM;
 284                 goto error;
 285         }
 286
 287         for (i = 0; i < nb_event; i++) {
 288                 offset += len;
 289                 strncpy(tmp_events[i].name, reply->payload + offset,
 290                                 sizeof(tmp_events[i].name));
 291                 tmp_events[i].pid = app->pid;
 292                 tmp_events[i].enabled = -1;
 293                 len = strlen(reply->payload + offset) + 1;
 294         }
 295
 296         *events = tmp_events;
 297
 298         free(reply);
 299         return nb_event;
 300
 301 error_io:
 302         ret = LTTNG_ERR_UST_LIST_FAIL;
 303 error:
 304         free(reply);
 305         free(tmp_events);
 306         return -ret;
 307
 308 }
 309
 310 /*
 311  * Internal enable JUL event on a JUL application. This function
 312  * communicates with the Java agent to enable a given event (Logger name).
 313  *
 314  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 315  */
 316 static int enable_event(struct jul_app *app, struct jul_event *event)
 317 {
 318         int ret;
 319         uint64_t data_size;
 320         struct lttcomm_jul_enable msg;
 321         struct lttcomm_jul_generic_reply reply;
 322
 323         assert(app);
 324         assert(app->sock);
 325         assert(event);
 326
 327         DBG2("JUL enabling event %s for app pid: %d and socket %d", event->name,
 328                         app->pid, app->sock->fd);
 329
 330         data_size = sizeof(msg);
 331
 332         ret = send_header(app->sock, data_size, JUL_CMD_ENABLE, 0);
 333         if (ret < 0) {
 334                 goto error_io;
 335         }
 336
 337         memset(&msg, 0, sizeof(msg));
 338         msg.loglevel = event->loglevel;
 339         msg.loglevel_type = event->loglevel_type;
 340         strncpy(msg.name, event->name, sizeof(msg.name));
 341         ret = send_payload(app->sock, &msg, sizeof(msg));
 342         if (ret < 0) {
 343                 goto error_io;
 344         }
 345
 346         ret = recv_reply(app->sock, &reply, sizeof(reply));
 347         if (ret < 0) {
 348                 goto error_io;
 349         }
 350
 351         switch (be32toh(reply.ret_code)) {
 352         case JUL_RET_CODE_SUCCESS:
 353                 break;
 354         case JUL_RET_CODE_UNKNOWN_NAME:
 355                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 356                 goto error;
 357         default:
 358                 ERR("Java agent returned an unknown code: %" PRIu32,
 359                                 be32toh(reply.ret_code));
 360                 ret = LTTNG_ERR_FATAL;
 361                 goto error;
 362         }
 363
 364         return LTTNG_OK;
 365
 366 error_io:
 367         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 368 error:
 369         return ret;
 370 }
 371
 372 /*
 373  * Internal disable JUL event call on a JUL application. This function
 374  * communicates with the Java agent to disable a given event (Logger name).
 375  *
 376  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 377  */
 378 static int disable_event(struct jul_app *app, struct jul_event *event)
 379 {
 380         int ret;
 381         uint64_t data_size;
 382         struct lttcomm_jul_disable msg;
 383         struct lttcomm_jul_generic_reply reply;
 384
 385         assert(app);
 386         assert(app->sock);
 387         assert(event);
 388
 389         DBG2("JUL disabling event %s for app pid: %d and socket %d", event->name,
 390                         app->pid, app->sock->fd);
 391
 392         data_size = sizeof(msg);
 393
 394         ret = send_header(app->sock, data_size, JUL_CMD_DISABLE, 0);
 395         if (ret < 0) {
 396                 goto error_io;
 397         }
 398
 399         memset(&msg, 0, sizeof(msg));
 400         strncpy(msg.name, event->name, sizeof(msg.name));
 401         ret = send_payload(app->sock, &msg, sizeof(msg));
 402         if (ret < 0) {
 403                 goto error_io;
 404         }
 405
 406         ret = recv_reply(app->sock, &reply, sizeof(reply));
 407         if (ret < 0) {
 408                 goto error_io;
 409         }
 410
 411         switch (be32toh(reply.ret_code)) {
 412                 case JUL_RET_CODE_SUCCESS:
 413                         break;
 414                 case JUL_RET_CODE_UNKNOWN_NAME:
 415                         ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 416                         goto error;
 417                 default:
 418                         ERR("Java agent returned an unknown code: %" PRIu32,
 419                                         be32toh(reply.ret_code));
 420                         ret = LTTNG_ERR_FATAL;
 421                         goto error;
 422         }
 423
 424         return LTTNG_OK;
 425
 426 error_io:
 427         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 428 error:
 429         return ret;
 430 }
 431
 432 /*
 433  * Send back the registration DONE command to a given JUL application.
 434  *
 435  * Return 0 on success or else a negative value.
 436  */
 437 int jul_send_registration_done(struct jul_app *app)
 438 {
 439         assert(app);
 440         assert(app->sock);
 441
 442         DBG("JUL sending registration done to app socket %d", app->sock->fd);
 443
 444         return send_header(app->sock, 0, JUL_CMD_REG_DONE, 0);
 445 }
 446
 447 /*
 448  * Enable JUL event on every JUL applications registered with the session
 449  * daemon.
 450  *
 451  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 452  */
 453 int jul_enable_event(struct jul_event *event)
 454 {
 455         int ret;
 456         struct jul_app *app;
 457         struct lttng_ht_iter iter;
 458
 459         assert(event);
 460
 461         rcu_read_lock();
 462
 463         cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, app,
 464                         node.node) {
 465                 /* Enable event on JUL application through TCP socket. */
 466                 ret = enable_event(app, event);
 467                 if (ret != LTTNG_OK) {
 468                         goto error;
 469                 }
 470         }
 471
 472         event->enabled = 1;
 473         ret = LTTNG_OK;
 474
 475 error:
 476         rcu_read_unlock();
 477         return ret;
 478 }
 479
 480 /*
 481  * Disable JUL event on every JUL applications registered with the session
 482  * daemon.
 483  *
 484  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 485  */
 486 int jul_disable_event(struct jul_event *event)
 487 {
 488         int ret;
 489         struct jul_app *app;
 490         struct lttng_ht_iter iter;
 491
 492         assert(event);
 493
 494         rcu_read_lock();
 495
 496         cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, app,
 497                         node.node) {
 498                 /* Enable event on JUL application through TCP socket. */
 499                 ret = disable_event(app, event);
 500                 if (ret != LTTNG_OK) {
 501                         goto error;
 502                 }
 503         }
 504
 505         event->enabled = 0;
 506         ret = LTTNG_OK;
 507
 508 error:
 509         rcu_read_unlock();
 510         return ret;
 511 }
 512
 513 /*
 514  * Ask every java agent for the list of possible event (logger name). Events is
 515  * allocated with the events of every JUL application.
 516  *
 517  * Return the number of events or else a negative value.
 518  */
 519 int jul_list_events(struct lttng_event **events)
 520 {
 521         int ret;
 522         size_t nbmem, count = 0;
 523         struct jul_app *app;
 524         struct lttng_event *tmp_events = NULL;
 525         struct lttng_ht_iter iter;
 526
 527         assert(events);
 528
 529         nbmem = UST_APP_EVENT_LIST_SIZE;
 530         tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
 531         if (!tmp_events) {
 532                 PERROR("zmalloc jul list events");
 533                 ret = -ENOMEM;
 534                 goto error;
 535         }
 536
 537         rcu_read_lock();
 538         cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, app,
 539                         node.node) {
 540                 ssize_t nb_ev;
 541                 struct lttng_event *jul_events;
 542
 543                 nb_ev = list_events(app, &jul_events);
 544                 if (nb_ev < 0) {
 545                         ret = nb_ev;
 546                         goto error_unlock;
 547                 }
 548
 549                 if (count + nb_ev > nbmem) {
 550                         /* In case the realloc fails, we free the memory */
 551                         struct lttng_event *new_tmp_events;
 552                         size_t new_nbmem;
 553
 554                         new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
 555                         DBG2("Reallocating JUL event list from %zu to %zu entries",
 556                                         nbmem, new_nbmem);
 557                         new_tmp_events = realloc(tmp_events,
 558                                 new_nbmem * sizeof(*new_tmp_events));
 559                         if (!new_tmp_events) {
 560                                 PERROR("realloc JUL events");
 561                                 ret = -ENOMEM;
 562                                 free(jul_events);
 563                                 goto error_unlock;
 564                         }
 565                         /* Zero the new memory */
 566                         memset(new_tmp_events + nbmem, 0,
 567                                 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
 568                         nbmem = new_nbmem;
 569                         tmp_events = new_tmp_events;
 570                 }
 571                 memcpy(tmp_events + count, jul_events,
 572                         nb_ev * sizeof(*tmp_events));
 573                 free(jul_events);
 574                 count += nb_ev;
 575         }
 576         rcu_read_unlock();
 577
 578         ret = count;
 579         *events = tmp_events;
 580         return ret;
 581
 582 error_unlock:
 583         rcu_read_unlock();
 584 error:
 585         free(tmp_events);
 586         return ret;
 587 }
 588
 589 /*
 590  * Create a JUL app object using the given PID.
 591  *
 592  * Return newly allocated object or else NULL on error.
 593  */
 594 struct jul_app *jul_create_app(pid_t pid, struct lttcomm_sock *sock)
 595 {
 596         struct jul_app *app;
 597
 598         assert(sock);
 599
 600         app = zmalloc(sizeof(*app));
 601         if (!app) {
 602                 PERROR("zmalloc JUL create");
 603                 goto error;
 604         }
 605
 606         app->pid = pid;
 607         app->sock = sock;
 608         lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
 609
 610 error:
 611         return app;
 612 }
 613
 614 /*
 615  * Lookup JUL app by socket in the global hash table.
 616  *
 617  * RCU read side lock MUST be acquired.
 618  *
 619  * Return object if found else NULL.
 620  */
 621 struct jul_app *jul_find_app_by_sock(int sock)
 622 {
 623         struct lttng_ht_node_ulong *node;
 624         struct lttng_ht_iter iter;
 625         struct jul_app *app;
 626
 627         assert(sock >= 0);
 628
 629         lttng_ht_lookup(jul_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
 630         node = lttng_ht_iter_get_node_ulong(&iter);
 631         if (node == NULL) {
 632                 goto error;
 633         }
 634         app = caa_container_of(node, struct jul_app, node);
 635
 636         DBG3("JUL app pid %d found by sock %d.", app->pid, sock);
 637         return app;
 638
 639 error:
 640         DBG3("JUL app NOT found by sock %d.", sock);
 641         return NULL;
 642 }
 643
 644 /*
 645  * Add JUL application object to a given hash table.
 646  */
 647 void jul_add_app(struct jul_app *app)
 648 {
 649         assert(app);
 650
 651         DBG3("JUL adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
 652
 653         rcu_read_lock();
 654         lttng_ht_add_unique_ulong(jul_apps_ht_by_sock, &app->node);
 655         rcu_read_unlock();
 656 }
 657
 658 /*
 659  * Delete JUL application from the global hash table.
 660  */
 661 void jul_delete_app(struct jul_app *app)
 662 {
 663         int ret;
 664         struct lttng_ht_iter iter;
 665
 666         assert(app);
 667
 668         DBG3("JUL deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
 669
 670         iter.iter.node = &app->node.node;
 671         rcu_read_lock();
 672         ret = lttng_ht_del(jul_apps_ht_by_sock, &iter);
 673         rcu_read_unlock();
 674         assert(!ret);
 675 }
 676
 677 /*
 678  * Destroy a JUL application object by detaching it from its corresponding UST
 679  * app if one is connected by closing the socket. Finally, perform a
 680  * delayed memory reclaim.
 681  */
 682 void jul_destroy_app(struct jul_app *app)
 683 {
 684         assert(app);
 685
 686         if (app->sock) {
 687                 app->sock->ops->close(app->sock);
 688                 lttcomm_destroy_sock(app->sock);
 689         }
 690
 691         call_rcu(&app->node.head, destroy_app_jul_rcu);
 692 }
 693
 694 /*
 695  * Initialize an already allocated JUL domain object.
 696  *
 697  * Return 0 on success or else a negative errno value.
 698  */
 699 int jul_init_domain(struct jul_domain *dom)
 700 {
 701         int ret;
 702
 703         assert(dom);
 704
 705         dom->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 706         if (!dom->events) {
 707                 ret = -ENOMEM;
 708                 goto error;
 709         }
 710
 711         return 0;
 712
 713 error:
 714         return ret;
 715 }
 716
 717 /*
 718  * Create a newly allocated JUL event data structure. If name is valid, it's
 719  * copied into the created event.
 720  *
 721  * Return a new object else NULL on error.
 722  */
 723 struct jul_event *jul_create_event(const char *name)
 724 {
 725         struct jul_event *event;
 726
 727         DBG3("JUL create new event with name %s", name);
 728
 729         event = zmalloc(sizeof(*event));
 730         if (!event) {
 731                 goto error;
 732         }
 733
 734         if (name) {
 735                 strncpy(event->name, name, sizeof(event->name));
 736                 event->name[sizeof(event->name) - 1] = '\0';
 737                 lttng_ht_node_init_str(&event->node, event->name);
 738         }
 739
 740 error:
 741         return event;
 742 }
 743
 744 /*
 745  * Unique add of a JUL event to a given domain.
 746  */
 747 void jul_add_event(struct jul_event *event, struct jul_domain *dom)
 748 {
 749         assert(event);
 750         assert(dom);
 751         assert(dom->events);
 752
 753         DBG3("JUL adding event %s to domain", event->name);
 754
 755         rcu_read_lock();
 756         add_unique_jul_event(dom->events, event);
 757         rcu_read_unlock();
 758         dom->being_used = 1;
 759 }
 760
 761 /*
 762  * Find a JUL event in the given domain using name and loglevel.
 763  *
 764  * RCU read side lock MUST be acquired.
 765  *
 766  * Return object if found else NULL.
 767  */
 768 struct jul_event *jul_find_event_by_name(const char *name,
 769                 struct jul_domain *dom)
 770 {
 771         struct lttng_ht_node_str *node;
 772         struct lttng_ht_iter iter;
 773         struct lttng_ht *ht;
 774         struct jul_ht_key key;
 775
 776         assert(name);
 777         assert(dom);
 778         assert(dom->events);
 779
 780         ht = dom->events;
 781         key.name = name;
 782
 783         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 784                         ht_match_event_by_name, &key, &iter.iter);
 785         node = lttng_ht_iter_get_node_str(&iter);
 786         if (node == NULL) {
 787                 goto error;
 788         }
 789
 790         DBG3("JUL event found %s by name.", name);
 791         return caa_container_of(node, struct jul_event, node);
 792
 793 error:
 794         DBG3("JUL NOT found by name %s.", name);
 795         return NULL;
 796 }
 797
 798 /*
 799  * Find a JUL event in the given domain using name and loglevel.
 800  *
 801  * RCU read side lock MUST be acquired.
 802  *
 803  * Return object if found else NULL.
 804  */
 805 struct jul_event *jul_find_event(const char *name,
 806                 enum lttng_loglevel_jul loglevel, struct jul_domain *dom)
 807 {
 808         struct lttng_ht_node_str *node;
 809         struct lttng_ht_iter iter;
 810         struct lttng_ht *ht;
 811         struct jul_ht_key key;
 812
 813         assert(name);
 814         assert(dom);
 815         assert(dom->events);
 816
 817         ht = dom->events;
 818         key.name = name;
 819         key.loglevel = loglevel;
 820
 821         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 822                         ht_match_event, &key, &iter.iter);
 823         node = lttng_ht_iter_get_node_str(&iter);
 824         if (node == NULL) {
 825                 goto error;
 826         }
 827
 828         DBG3("JUL event found %s.", name);
 829         return caa_container_of(node, struct jul_event, node);
 830
 831 error:
 832         DBG3("JUL NOT found %s.", name);
 833         return NULL;
 834 }
 835
 836 /*
 837  * Free given JUL event. This event must not be globally visible at this
 838  * point (only expected to be used on failure just after event
 839  * creation). After this call, the pointer is not usable anymore.
 840  */
 841 void jul_destroy_event(struct jul_event *event)
 842 {
 843         assert(event);
 844
 845         free(event);
 846 }
 847
 848 /*
 849  * Destroy a JUL domain completely. Note that the given pointer is NOT freed
 850  * thus a reference to static or stack data can be passed to this function.
 851  */
 852 void jul_destroy_domain(struct jul_domain *dom)
 853 {
 854         struct lttng_ht_node_str *node;
 855         struct lttng_ht_iter iter;
 856
 857         assert(dom);
 858
 859         DBG3("JUL destroy domain");
 860
 861         /*
 862          * Just ignore if no events hash table exists. This is possible if for
 863          * instance a JUL domain object was allocated but not initialized.
 864          */
 865         if (!dom->events) {
 866                 return;
 867         }
 868
 869         rcu_read_lock();
 870         cds_lfht_for_each_entry(dom->events->ht, &iter.iter, node, node) {
 871                 int ret;
 872
 873                 ret = lttng_ht_del(dom->events, &iter);
 874                 assert(!ret);
 875                 call_rcu(&node->head, destroy_event_jul_rcu);
 876         }
 877         rcu_read_unlock();
 878
 879         lttng_ht_destroy(dom->events);
 880 }
 881
 882 /*
 883  * Initialize JUL subsystem.
 884  */
 885 int jul_init(void)
 886 {
 887         jul_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 888         if (!jul_apps_ht_by_sock) {
 889                 return -1;
 890         }
 891
 892         return 0;
 893 }
 894
 895 /*
 896  * Update a JUL application (given socket) using the given domain.
 897  *
 898  * Note that this function is most likely to be used with a tracing session
 899  * thus the caller should make sure to hold the appropriate lock(s).
 900  */
 901 void jul_update(struct jul_domain *domain, int sock)
 902 {
 903         int ret;
 904         struct jul_app *app;
 905         struct jul_event *event;
 906         struct lttng_ht_iter iter;
 907
 908         assert(domain);
 909         assert(sock >= 0);
 910
 911         DBG("JUL updating app socket %d", sock);
 912
 913         rcu_read_lock();
 914         cds_lfht_for_each_entry(domain->events->ht, &iter.iter, event, node.node) {
 915                 /* Skip event if disabled. */
 916                 if (!event->enabled) {
 917                         continue;
 918                 }
 919
 920                 app = jul_find_app_by_sock(sock);
 921                 /*
 922                  * We are in the registration path thus if the application is gone,
 923                  * there is a serious code flow error.
 924                  */
 925                 assert(app);
 926
 927                 ret = enable_event(app, event);
 928                 if (ret != LTTNG_OK) {
 929                         DBG2("JUL update unable to enable event %s on app pid: %d sock %d",
 930                                         event->name, app->pid, app->sock->fd);
 931                         /* Let's try the others here and don't assume the app is dead. */
 932                         continue;
 933                 }
 934         }
 935         rcu_read_unlock();
 936 }