src/bin/lttng-sessiond/agent.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 #define _LGPL_SOURCE
  20 #include <assert.h>
  21 #include <urcu/uatomic.h>
  22
  23 #include <common/common.h>
  24 #include <common/sessiond-comm/agent.h>
  25
  26 #include <common/compat/endian.h>
  27
  28 #include "agent.h"
  29 #include "ust-app.h"
  30 #include "utils.h"
  31
  32 /*
  33  * Match function for the events hash table lookup by name.
  34  */
  35 static int ht_match_event_by_name(struct cds_lfht_node *node,
  36                 const void *_key)
  37 {
  38         struct agent_event *event;
  39         const struct agent_ht_key *key;
  40
  41         assert(node);
  42         assert(_key);
  43
  44         event = caa_container_of(node, struct agent_event, node.node);
  45         key = _key;
  46
  47         /* Match 1 elements of the key: name. */
  48
  49         /* Event name */
  50         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  51                 goto no_match;
  52         }
  53         /* Match. */
  54         return 1;
  55
  56 no_match:
  57         return 0;
  58 }
  59
  60 /*
  61  * Match function for the events hash table lookup by name and loglevel.
  62  */
  63 static int ht_match_event(struct cds_lfht_node *node,
  64                 const void *_key)
  65 {
  66         struct agent_event *event;
  67         const struct agent_ht_key *key;
  68         int ll_match;
  69
  70         assert(node);
  71         assert(_key);
  72
  73         event = caa_container_of(node, struct agent_event, node.node);
  74         key = _key;
  75
  76         /* Match 2 elements of the key: name and loglevel. */
  77
  78         /* Event name */
  79         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  80                 goto no_match;
  81         }
  82
  83         /* Event loglevel value and type. */
  84         ll_match = loglevels_match(event->loglevel_type,
  85                 event->loglevel_value, key->loglevel_type,
  86                 key->loglevel_value, LTTNG_EVENT_LOGLEVEL_ALL);
  87
  88         if (!ll_match) {
  89                 goto no_match;
  90         }
  91
  92         return 1;
  93
  94 no_match:
  95         return 0;
  96 }
  97
  98 /*
  99  * Add unique agent event based on the event name and loglevel.
 100  */
 101 static void add_unique_agent_event(struct lttng_ht *ht,
 102                 struct agent_event *event)
 103 {
 104         struct cds_lfht_node *node_ptr;
 105         struct agent_ht_key key;
 106
 107         assert(ht);
 108         assert(ht->ht);
 109         assert(event);
 110
 111         key.name = event->name;
 112         key.loglevel_value = event->loglevel_value;
 113         key.loglevel_type = event->loglevel_type;
 114
 115         node_ptr = cds_lfht_add_unique(ht->ht,
 116                         ht->hash_fct(event->node.key, lttng_ht_seed),
 117                         ht_match_event, &key, &event->node.node);
 118         assert(node_ptr == &event->node.node);
 119 }
 120
 121 /*
 122  * URCU delayed agent event reclaim.
 123  */
 124 static void destroy_event_agent_rcu(struct rcu_head *head)
 125 {
 126         struct lttng_ht_node_str *node =
 127                 caa_container_of(head, struct lttng_ht_node_str, head);
 128         struct agent_event *event =
 129                 caa_container_of(node, struct agent_event, node);
 130
 131         agent_destroy_event(event);
 132 }
 133
 134 /*
 135  * URCU delayed agent app reclaim.
 136  */
 137 static void destroy_app_agent_rcu(struct rcu_head *head)
 138 {
 139         struct lttng_ht_node_ulong *node =
 140                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 141         struct agent_app *app =
 142                 caa_container_of(node, struct agent_app, node);
 143
 144         free(app);
 145 }
 146
 147 /*
 148  * Communication with the agent. Send the message header to the given socket in
 149  * big endian.
 150  *
 151  * Return 0 on success or else a negative errno message of sendmsg() op.
 152  */
 153 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
 154                 uint32_t cmd, uint32_t cmd_version)
 155 {
 156         int ret;
 157         ssize_t size;
 158         struct lttcomm_agent_hdr msg;
 159
 160         assert(sock);
 161
 162         memset(&msg, 0, sizeof(msg));
 163         msg.data_size = htobe64(data_size);
 164         msg.cmd = htobe32(cmd);
 165         msg.cmd_version = htobe32(cmd_version);
 166
 167         size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
 168         if (size < sizeof(msg)) {
 169                 ret = -errno;
 170                 goto error;
 171         }
 172         ret = 0;
 173
 174 error:
 175         return ret;
 176 }
 177
 178 /*
 179  * Communication call with the agent. Send the payload to the given socket. The
 180  * header MUST be sent prior to this call.
 181  *
 182  * Return 0 on success or else a negative errno value of sendmsg() op.
 183  */
 184 static int send_payload(struct lttcomm_sock *sock, void *data,
 185                 size_t size)
 186 {
 187         int ret;
 188         ssize_t len;
 189
 190         assert(sock);
 191         assert(data);
 192
 193         len = sock->ops->sendmsg(sock, data, size, 0);
 194         if (len < size) {
 195                 ret = -errno;
 196                 goto error;
 197         }
 198         ret = 0;
 199
 200 error:
 201         return ret;
 202 }
 203
 204 /*
 205  * Communication call with the agent. Receive reply from the agent using the
 206  * given socket.
 207  *
 208  * Return 0 on success or else a negative errno value from recvmsg() op.
 209  */
 210 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
 211 {
 212         int ret;
 213         ssize_t len;
 214
 215         assert(sock);
 216         assert(buf);
 217
 218         len = sock->ops->recvmsg(sock, buf, size, 0);
 219         if (len < size) {
 220                 ret = -errno;
 221                 goto error;
 222         }
 223         ret = 0;
 224
 225 error:
 226         return ret;
 227 }
 228
 229 /*
 230  * Internal event listing for a given app. Populate events.
 231  *
 232  * Return number of element in the list or else a negative LTTNG_ERR* code.
 233  * On success, the caller is responsible for freeing the memory
 234  * allocated for "events".
 235  */
 236 static ssize_t list_events(struct agent_app *app, struct lttng_event **events)
 237 {
 238         int ret, i, len = 0, offset = 0;
 239         uint32_t nb_event;
 240         size_t data_size;
 241         struct lttng_event *tmp_events = NULL;
 242         struct lttcomm_agent_list_reply *reply = NULL;
 243         struct lttcomm_agent_list_reply_hdr reply_hdr;
 244
 245         assert(app);
 246         assert(app->sock);
 247         assert(events);
 248
 249         DBG2("Agent listing events for app pid: %d and socket %d", app->pid,
 250                         app->sock->fd);
 251
 252         ret = send_header(app->sock, 0, AGENT_CMD_LIST, 0);
 253         if (ret < 0) {
 254                 goto error_io;
 255         }
 256
 257         /* Get list header so we know how much we'll receive. */
 258         ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
 259         if (ret < 0) {
 260                 goto error_io;
 261         }
 262
 263         switch (be32toh(reply_hdr.ret_code)) {
 264         case AGENT_RET_CODE_SUCCESS:
 265                 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
 266                 break;
 267         default:
 268                 ERR("Agent returned an unknown code: %" PRIu32,
 269                                 be32toh(reply_hdr.ret_code));
 270                 ret = LTTNG_ERR_FATAL;
 271                 goto error;
 272         }
 273
 274         reply = zmalloc(data_size);
 275         if (!reply) {
 276                 ret = LTTNG_ERR_NOMEM;
 277                 goto error;
 278         }
 279
 280         /* Get the list with the appropriate data size. */
 281         ret = recv_reply(app->sock, reply, data_size);
 282         if (ret < 0) {
 283                 goto error_io;
 284         }
 285
 286         nb_event = be32toh(reply->nb_event);
 287         tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
 288         if (!tmp_events) {
 289                 ret = LTTNG_ERR_NOMEM;
 290                 goto error;
 291         }
 292
 293         for (i = 0; i < nb_event; i++) {
 294                 offset += len;
 295                 strncpy(tmp_events[i].name, reply->payload + offset,
 296                                 sizeof(tmp_events[i].name));
 297                 tmp_events[i].pid = app->pid;
 298                 tmp_events[i].enabled = -1;
 299                 len = strlen(reply->payload + offset) + 1;
 300         }
 301
 302         *events = tmp_events;
 303
 304         free(reply);
 305         return nb_event;
 306
 307 error_io:
 308         ret = LTTNG_ERR_UST_LIST_FAIL;
 309 error:
 310         free(reply);
 311         free(tmp_events);
 312         return -ret;
 313
 314 }
 315
 316 /*
 317  * Internal enable agent event on a agent application. This function
 318  * communicates with the agent to enable a given event.
 319  *
 320  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 321  */
 322 static int enable_event(struct agent_app *app, struct agent_event *event)
 323 {
 324         int ret;
 325         uint64_t data_size;
 326         struct lttcomm_agent_enable msg;
 327         struct lttcomm_agent_generic_reply reply;
 328
 329         assert(app);
 330         assert(app->sock);
 331         assert(event);
 332
 333         DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
 334                         app->pid, app->sock->fd);
 335
 336         data_size = sizeof(msg);
 337
 338         ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
 339         if (ret < 0) {
 340                 goto error_io;
 341         }
 342
 343         memset(&msg, 0, sizeof(msg));
 344         msg.loglevel_value = event->loglevel_value;
 345         msg.loglevel_type = event->loglevel_type;
 346         strncpy(msg.name, event->name, sizeof(msg.name));
 347         ret = send_payload(app->sock, &msg, sizeof(msg));
 348         if (ret < 0) {
 349                 goto error_io;
 350         }
 351
 352         ret = recv_reply(app->sock, &reply, sizeof(reply));
 353         if (ret < 0) {
 354                 goto error_io;
 355         }
 356
 357         switch (be32toh(reply.ret_code)) {
 358         case AGENT_RET_CODE_SUCCESS:
 359                 break;
 360         case AGENT_RET_CODE_UNKNOWN_NAME:
 361                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 362                 goto error;
 363         default:
 364                 ERR("Agent returned an unknown code: %" PRIu32,
 365                                 be32toh(reply.ret_code));
 366                 ret = LTTNG_ERR_FATAL;
 367                 goto error;
 368         }
 369
 370         return LTTNG_OK;
 371
 372 error_io:
 373         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 374 error:
 375         return ret;
 376 }
 377
 378 /*
 379  * Internal disable agent event call on a agent application. This function
 380  * communicates with the agent to disable a given event.
 381  *
 382  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 383  */
 384 static int disable_event(struct agent_app *app, struct agent_event *event)
 385 {
 386         int ret;
 387         uint64_t data_size;
 388         struct lttcomm_agent_disable msg;
 389         struct lttcomm_agent_generic_reply reply;
 390
 391         assert(app);
 392         assert(app->sock);
 393         assert(event);
 394
 395         DBG2("Agent disabling event %s for app pid: %d and socket %d", event->name,
 396                         app->pid, app->sock->fd);
 397
 398         data_size = sizeof(msg);
 399
 400         ret = send_header(app->sock, data_size, AGENT_CMD_DISABLE, 0);
 401         if (ret < 0) {
 402                 goto error_io;
 403         }
 404
 405         memset(&msg, 0, sizeof(msg));
 406         strncpy(msg.name, event->name, sizeof(msg.name));
 407         ret = send_payload(app->sock, &msg, sizeof(msg));
 408         if (ret < 0) {
 409                 goto error_io;
 410         }
 411
 412         ret = recv_reply(app->sock, &reply, sizeof(reply));
 413         if (ret < 0) {
 414                 goto error_io;
 415         }
 416
 417         switch (be32toh(reply.ret_code)) {
 418         case AGENT_RET_CODE_SUCCESS:
 419                 break;
 420         case AGENT_RET_CODE_UNKNOWN_NAME:
 421                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 422                 goto error;
 423         default:
 424                 ERR("Agent returned an unknown code: %" PRIu32,
 425                                 be32toh(reply.ret_code));
 426                 ret = LTTNG_ERR_FATAL;
 427                 goto error;
 428         }
 429
 430         return LTTNG_OK;
 431
 432 error_io:
 433         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 434 error:
 435         return ret;
 436 }
 437
 438 /*
 439  * Send back the registration DONE command to a given agent application.
 440  *
 441  * Return 0 on success or else a negative value.
 442  */
 443 int agent_send_registration_done(struct agent_app *app)
 444 {
 445         assert(app);
 446         assert(app->sock);
 447
 448         DBG("Agent sending registration done to app socket %d", app->sock->fd);
 449
 450         return send_header(app->sock, 0, AGENT_CMD_REG_DONE, 0);
 451 }
 452
 453 /*
 454  * Enable agent event on every agent applications registered with the session
 455  * daemon.
 456  *
 457  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 458  */
 459 int agent_enable_event(struct agent_event *event,
 460                 enum lttng_domain_type domain)
 461 {
 462         int ret;
 463         struct agent_app *app;
 464         struct lttng_ht_iter iter;
 465
 466         assert(event);
 467
 468         rcu_read_lock();
 469
 470         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 471                         node.node) {
 472                 if (app->domain != domain) {
 473                         continue;
 474                 }
 475
 476                 /* Enable event on agent application through TCP socket. */
 477                 ret = enable_event(app, event);
 478                 if (ret != LTTNG_OK) {
 479                         goto error;
 480                 }
 481         }
 482
 483         event->enabled = 1;
 484         ret = LTTNG_OK;
 485
 486 error:
 487         rcu_read_unlock();
 488         return ret;
 489 }
 490
 491 /*
 492  * Disable agent event on every agent applications registered with the session
 493  * daemon.
 494  *
 495  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 496  */
 497 int agent_disable_event(struct agent_event *event,
 498                 enum lttng_domain_type domain)
 499 {
 500         int ret = LTTNG_OK;
 501         struct agent_app *app;
 502         struct lttng_ht_iter iter;
 503
 504         assert(event);
 505         if (!event->enabled) {
 506                 goto end;
 507         }
 508
 509         rcu_read_lock();
 510
 511         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 512                         node.node) {
 513                 if (app->domain != domain) {
 514                         continue;
 515                 }
 516
 517                 /* Enable event on agent application through TCP socket. */
 518                 ret = disable_event(app, event);
 519                 if (ret != LTTNG_OK) {
 520                         goto error;
 521                 }
 522         }
 523
 524         event->enabled = 0;
 525
 526 error:
 527         rcu_read_unlock();
 528 end:
 529         return ret;
 530 }
 531
 532 /*
 533  * Ask every agent for the list of possible event. Events is allocated with the
 534  * events of every agent application.
 535  *
 536  * Return the number of events or else a negative value.
 537  */
 538 int agent_list_events(struct lttng_event **events,
 539                 enum lttng_domain_type domain)
 540 {
 541         int ret;
 542         size_t nbmem, count = 0;
 543         struct agent_app *app;
 544         struct lttng_event *tmp_events = NULL;
 545         struct lttng_ht_iter iter;
 546
 547         assert(events);
 548
 549         DBG2("Agent listing events for domain %d", domain);
 550
 551         nbmem = UST_APP_EVENT_LIST_SIZE;
 552         tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
 553         if (!tmp_events) {
 554                 PERROR("zmalloc agent list events");
 555                 ret = -ENOMEM;
 556                 goto error;
 557         }
 558
 559         rcu_read_lock();
 560         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 561                         node.node) {
 562                 ssize_t nb_ev;
 563                 struct lttng_event *agent_events;
 564
 565                 /* Skip domain not asked by the list. */
 566                 if (app->domain != domain) {
 567                         continue;
 568                 }
 569
 570                 nb_ev = list_events(app, &agent_events);
 571                 if (nb_ev < 0) {
 572                         ret = nb_ev;
 573                         goto error_unlock;
 574                 }
 575
 576                 if (count + nb_ev > nbmem) {
 577                         /* In case the realloc fails, we free the memory */
 578                         struct lttng_event *new_tmp_events;
 579                         size_t new_nbmem;
 580
 581                         new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
 582                         DBG2("Reallocating agent event list from %zu to %zu entries",
 583                                         nbmem, new_nbmem);
 584                         new_tmp_events = realloc(tmp_events,
 585                                 new_nbmem * sizeof(*new_tmp_events));
 586                         if (!new_tmp_events) {
 587                                 PERROR("realloc agent events");
 588                                 ret = -ENOMEM;
 589                                 free(agent_events);
 590                                 goto error_unlock;
 591                         }
 592                         /* Zero the new memory */
 593                         memset(new_tmp_events + nbmem, 0,
 594                                 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
 595                         nbmem = new_nbmem;
 596                         tmp_events = new_tmp_events;
 597                 }
 598                 memcpy(tmp_events + count, agent_events,
 599                         nb_ev * sizeof(*tmp_events));
 600                 free(agent_events);
 601                 count += nb_ev;
 602         }
 603         rcu_read_unlock();
 604
 605         ret = count;
 606         *events = tmp_events;
 607         return ret;
 608
 609 error_unlock:
 610         rcu_read_unlock();
 611 error:
 612         free(tmp_events);
 613         return ret;
 614 }
 615
 616 /*
 617  * Create a agent app object using the given PID.
 618  *
 619  * Return newly allocated object or else NULL on error.
 620  */
 621 struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
 622                 struct lttcomm_sock *sock)
 623 {
 624         struct agent_app *app;
 625
 626         assert(sock);
 627
 628         app = zmalloc(sizeof(*app));
 629         if (!app) {
 630                 PERROR("zmalloc agent create");
 631                 goto error;
 632         }
 633
 634         app->pid = pid;
 635         app->domain = domain;
 636         app->sock = sock;
 637         lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
 638
 639 error:
 640         return app;
 641 }
 642
 643 /*
 644  * Lookup agent app by socket in the global hash table.
 645  *
 646  * RCU read side lock MUST be acquired.
 647  *
 648  * Return object if found else NULL.
 649  */
 650 struct agent_app *agent_find_app_by_sock(int sock)
 651 {
 652         struct lttng_ht_node_ulong *node;
 653         struct lttng_ht_iter iter;
 654         struct agent_app *app;
 655
 656         assert(sock >= 0);
 657
 658         lttng_ht_lookup(agent_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
 659         node = lttng_ht_iter_get_node_ulong(&iter);
 660         if (node == NULL) {
 661                 goto error;
 662         }
 663         app = caa_container_of(node, struct agent_app, node);
 664
 665         DBG3("Agent app pid %d found by sock %d.", app->pid, sock);
 666         return app;
 667
 668 error:
 669         DBG3("Agent app NOT found by sock %d.", sock);
 670         return NULL;
 671 }
 672
 673 /*
 674  * Add agent application object to the global hash table.
 675  */
 676 void agent_add_app(struct agent_app *app)
 677 {
 678         assert(app);
 679
 680         DBG3("Agent adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
 681
 682         rcu_read_lock();
 683         lttng_ht_add_unique_ulong(agent_apps_ht_by_sock, &app->node);
 684         rcu_read_unlock();
 685 }
 686
 687 /*
 688  * Delete agent application from the global hash table.
 689  *
 690  * rcu_read_lock() must be held by the caller.
 691  */
 692 void agent_delete_app(struct agent_app *app)
 693 {
 694         int ret;
 695         struct lttng_ht_iter iter;
 696
 697         assert(app);
 698
 699         DBG3("Agent deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
 700
 701         iter.iter.node = &app->node.node;
 702         ret = lttng_ht_del(agent_apps_ht_by_sock, &iter);
 703         assert(!ret);
 704 }
 705
 706 /*
 707  * Destroy a agent application object by detaching it from its corresponding
 708  * UST app if one is connected by closing the socket. Finally, perform a
 709  * delayed memory reclaim.
 710  */
 711 void agent_destroy_app(struct agent_app *app)
 712 {
 713         assert(app);
 714
 715         if (app->sock) {
 716                 app->sock->ops->close(app->sock);
 717                 lttcomm_destroy_sock(app->sock);
 718         }
 719
 720         call_rcu(&app->node.head, destroy_app_agent_rcu);
 721 }
 722
 723 /*
 724  * Initialize an already allocated agent object.
 725  *
 726  * Return 0 on success or else a negative errno value.
 727  */
 728 int agent_init(struct agent *agt)
 729 {
 730         int ret;
 731
 732         assert(agt);
 733
 734         agt->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 735         if (!agt->events) {
 736                 ret = -ENOMEM;
 737                 goto error;
 738         }
 739         lttng_ht_node_init_u64(&agt->node, agt->domain);
 740
 741         return 0;
 742
 743 error:
 744         return ret;
 745 }
 746
 747 /*
 748  * Add agent object to the given hash table.
 749  */
 750 void agent_add(struct agent *agt, struct lttng_ht *ht)
 751 {
 752         assert(agt);
 753         assert(ht);
 754
 755         DBG3("Agent adding from domain %d", agt->domain);
 756
 757         rcu_read_lock();
 758         lttng_ht_add_unique_u64(ht, &agt->node);
 759         rcu_read_unlock();
 760 }
 761
 762 /*
 763  * Create an agent object for the given domain.
 764  *
 765  * Return the allocated agent or NULL on error.
 766  */
 767 struct agent *agent_create(enum lttng_domain_type domain)
 768 {
 769         int ret;
 770         struct agent *agt;
 771
 772         agt = zmalloc(sizeof(*agt));
 773         if (!agt) {
 774                 goto error;
 775         }
 776         agt->domain = domain;
 777
 778         ret = agent_init(agt);
 779         if (ret < 0) {
 780                 free(agt);
 781                 agt = NULL;
 782                 goto error;
 783         }
 784
 785 error:
 786         return agt;
 787 }
 788
 789 /*
 790  * Create a newly allocated agent event data structure.
 791  * Ownership of filter_expression is taken.
 792  *
 793  * Return a new object else NULL on error.
 794  */
 795 struct agent_event *agent_create_event(const char *name,
 796                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 797                 struct lttng_filter_bytecode *filter, char *filter_expression)
 798 {
 799         struct agent_event *event = NULL;
 800
 801         DBG3("Agent create new event with name %s, loglevel type %d and loglevel value %d",
 802                 name, loglevel_type, loglevel_value);
 803
 804         if (!name) {
 805                 ERR("Failed to create agent event; no name provided.");
 806                 goto error;
 807         }
 808
 809         event = zmalloc(sizeof(*event));
 810         if (!event) {
 811                 goto error;
 812         }
 813
 814         strncpy(event->name, name, sizeof(event->name));
 815         event->name[sizeof(event->name) - 1] = '\0';
 816         lttng_ht_node_init_str(&event->node, event->name);
 817
 818         event->loglevel_value = loglevel_value;
 819         event->loglevel_type = loglevel_type;
 820         event->filter = filter;
 821         event->filter_expression = filter_expression;
 822 error:
 823         return event;
 824 }
 825
 826 /*
 827  * Unique add of a agent event to an agent object.
 828  */
 829 void agent_add_event(struct agent_event *event, struct agent *agt)
 830 {
 831         assert(event);
 832         assert(agt);
 833         assert(agt->events);
 834
 835         DBG3("Agent adding event %s", event->name);
 836
 837         rcu_read_lock();
 838         add_unique_agent_event(agt->events, event);
 839         rcu_read_unlock();
 840         agt->being_used = 1;
 841 }
 842
 843 /*
 844  * Find multiple agent events sharing the given name.
 845  *
 846  * RCU read side lock MUST be acquired. It must be held for the
 847  * duration of the iteration.
 848  *
 849  * Sets the given iterator.
 850  */
 851 void agent_find_events_by_name(const char *name, struct agent *agt,
 852                 struct lttng_ht_iter* iter)
 853 {
 854         struct lttng_ht *ht;
 855         struct agent_ht_key key;
 856
 857         assert(name);
 858         assert(agt);
 859         assert(agt->events);
 860         assert(iter);
 861
 862         ht = agt->events;
 863         key.name = name;
 864
 865         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 866                         ht_match_event_by_name, &key, &iter->iter);
 867 }
 868
 869 /*
 870  * Get the next agent event duplicate by name. This should be called
 871  * after a call to agent_find_events_by_name() to iterate on events.
 872  *
 873  * The RCU read lock must be held during the iteration and for as long
 874  * as the object the iterator points to remains in use.
 875  */
 876 void agent_event_next_duplicate(const char *name,
 877                 struct agent *agt, struct lttng_ht_iter* iter)
 878 {
 879         struct agent_ht_key key;
 880
 881         key.name = name;
 882
 883         cds_lfht_next_duplicate(agt->events->ht, ht_match_event_by_name,
 884                 &key, &iter->iter);
 885 }
 886
 887 /*
 888  * Find a agent event in the given agent using name and loglevel.
 889  *
 890  * RCU read side lock MUST be acquired.
 891  *
 892  * Return object if found else NULL.
 893  */
 894 struct agent_event *agent_find_event(const char *name,
 895                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 896                 struct agent *agt)
 897 {
 898         struct lttng_ht_node_str *node;
 899         struct lttng_ht_iter iter;
 900         struct lttng_ht *ht;
 901         struct agent_ht_key key;
 902
 903         assert(name);
 904         assert(agt);
 905         assert(agt->events);
 906
 907         ht = agt->events;
 908         key.name = name;
 909         key.loglevel_value = loglevel_value;
 910         key.loglevel_type = loglevel_type;
 911
 912         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 913                         ht_match_event, &key, &iter.iter);
 914         node = lttng_ht_iter_get_node_str(&iter);
 915         if (node == NULL) {
 916                 goto error;
 917         }
 918
 919         DBG3("Agent event found %s.", name);
 920         return caa_container_of(node, struct agent_event, node);
 921
 922 error:
 923         DBG3("Agent event NOT found %s.", name);
 924         return NULL;
 925 }
 926
 927 /*
 928  * Free given agent event. This event must not be globally visible at this
 929  * point (only expected to be used on failure just after event creation). After
 930  * this call, the pointer is not usable anymore.
 931  */
 932 void agent_destroy_event(struct agent_event *event)
 933 {
 934         assert(event);
 935
 936         free(event->filter);
 937         free(event->filter_expression);
 938         free(event->exclusion);
 939         free(event);
 940 }
 941
 942 /*
 943  * Destroy an agent completely.
 944  */
 945 void agent_destroy(struct agent *agt)
 946 {
 947         struct lttng_ht_node_str *node;
 948         struct lttng_ht_iter iter;
 949
 950         assert(agt);
 951
 952         DBG3("Agent destroy");
 953
 954         /*
 955          * Just ignore if no events hash table exists. This is possible if for
 956          * instance an agent object was allocated but not initialized.
 957          */
 958         if (!agt->events) {
 959                 return;
 960         }
 961
 962         rcu_read_lock();
 963         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, node, node) {
 964                 int ret;
 965                 struct agent_event *event;
 966
 967                 /*
 968                  * When destroying an event, we have to try to disable it on the agent
 969                  * side so the event stops generating data. The return value is not
 970                  * important since we have to continue anyway destroying the object.
 971                  */
 972                 event = caa_container_of(node, struct agent_event, node);
 973                 (void) agent_disable_event(event, agt->domain);
 974
 975                 ret = lttng_ht_del(agt->events, &iter);
 976                 assert(!ret);
 977                 call_rcu(&node->head, destroy_event_agent_rcu);
 978         }
 979         rcu_read_unlock();
 980
 981         ht_cleanup_push(agt->events);
 982         free(agt);
 983 }
 984
 985 /*
 986  * Allocate agent_apps_ht_by_sock.
 987  */
 988 int agent_app_ht_alloc(void)
 989 {
 990         int ret = 0;
 991
 992         agent_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 993         if (!agent_apps_ht_by_sock) {
 994                 ret = -1;
 995         }
 996
 997         return ret;
 998 }
 999
1000 /*
1001  * Destroy a agent application by socket.
1002  */
1003 void agent_destroy_app_by_sock(int sock)
1004 {
1005         struct agent_app *app;
1006
1007         assert(sock >= 0);
1008
1009         /*
1010          * Not finding an application is a very important error that should NEVER
1011          * happen. The hash table deletion is ONLY done through this call when the
1012          * main sessiond thread is torn down.
1013          */
1014         rcu_read_lock();
1015         app = agent_find_app_by_sock(sock);
1016         assert(app);
1017
1018         /* RCU read side lock is assumed to be held by this function. */
1019         agent_delete_app(app);
1020
1021         /* The application is freed in a RCU call but the socket is closed here. */
1022         agent_destroy_app(app);
1023         rcu_read_unlock();
1024 }
1025
1026 /*
1027  * Clean-up the agent app hash table and destroy it.
1028  */
1029 void agent_app_ht_clean(void)
1030 {
1031         struct lttng_ht_node_ulong *node;
1032         struct lttng_ht_iter iter;
1033
1034         if (!agent_apps_ht_by_sock) {
1035                 return;
1036         }
1037         rcu_read_lock();
1038         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) {
1039                 struct agent_app *app;
1040
1041                 app = caa_container_of(node, struct agent_app, node);
1042                 agent_destroy_app_by_sock(app->sock->fd);
1043         }
1044         rcu_read_unlock();
1045
1046         lttng_ht_destroy(agent_apps_ht_by_sock);
1047 }
1048
1049 /*
1050  * Update a agent application (given socket) using the given agent.
1051  *
1052  * Note that this function is most likely to be used with a tracing session
1053  * thus the caller should make sure to hold the appropriate lock(s).
1054  */
1055 void agent_update(struct agent *agt, int sock)
1056 {
1057         int ret;
1058         struct agent_app *app;
1059         struct agent_event *event;
1060         struct lttng_ht_iter iter;
1061
1062         assert(agt);
1063         assert(sock >= 0);
1064
1065         DBG("Agent updating app socket %d", sock);
1066
1067         rcu_read_lock();
1068         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
1069                 /* Skip event if disabled. */
1070                 if (!event->enabled) {
1071                         continue;
1072                 }
1073
1074                 app = agent_find_app_by_sock(sock);
1075                 /*
1076                  * We are in the registration path thus if the application is gone,
1077                  * there is a serious code flow error.
1078                  */
1079                 assert(app);
1080
1081                 ret = enable_event(app, event);
1082                 if (ret != LTTNG_OK) {
1083                         DBG2("Agent update unable to enable event %s on app pid: %d sock %d",
1084                                         event->name, app->pid, app->sock->fd);
1085                         /* Let's try the others here and don't assume the app is dead. */
1086                         continue;
1087                 }
1088         }
1089         rcu_read_unlock();
1090 }