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 _LGPL_SOURCE
  19 #include <assert.h>
  20 #include <urcu/uatomic.h>
  21
  22 #include <common/common.h>
  23 #include <common/sessiond-comm/agent.h>
  24
  25 #include <common/compat/endian.h>
  26
  27 #include "agent.h"
  28 #include "ust-app.h"
  29 #include "utils.h"
  30 #include "error.h"
  31
  32 #define AGENT_RET_CODE_INDEX(code) (code - AGENT_RET_CODE_SUCCESS)
  33
  34 /*
  35  * Human readable agent return code.
  36  */
  37 static const char *error_string_array[] = {
  38         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_SUCCESS) ] = "Success",
  39         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_INVALID) ] = "Invalid command",
  40         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_UNKNOWN_NAME) ] = "Unknown logger name",
  41
  42         /* Last element */
  43         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_NR) ] = "Unknown code",
  44 };
  45
  46 static
  47 void log_reply_code(uint32_t in_reply_ret_code)
  48 {
  49         int level = PRINT_DBG3;
  50         /*
  51          * reply_ret_code and in_reply_ret_code are kept separate to have a
  52          * sanitized value (used to retrieve the human readable string) and the
  53          * original value which is logged as-is.
  54          */
  55         uint32_t reply_ret_code = in_reply_ret_code;
  56
  57         if (reply_ret_code < AGENT_RET_CODE_SUCCESS ||
  58                         reply_ret_code >= AGENT_RET_CODE_NR) {
  59                 reply_ret_code = AGENT_RET_CODE_NR;
  60                 level = PRINT_ERR;
  61         }
  62
  63         LOG(level, "Agent replied with retcode: %s (%"PRIu32")",
  64                         error_string_array[AGENT_RET_CODE_INDEX(
  65                         reply_ret_code)],
  66                         in_reply_ret_code);
  67 }
  68
  69 /*
  70  * Match function for the events hash table lookup by name.
  71  */
  72 static int ht_match_event_by_name(struct cds_lfht_node *node,
  73                 const void *_key)
  74 {
  75         struct agent_event *event;
  76         const struct agent_ht_key *key;
  77
  78         assert(node);
  79         assert(_key);
  80
  81         event = caa_container_of(node, struct agent_event, node.node);
  82         key = _key;
  83
  84         /* Match 1 elements of the key: name. */
  85
  86         /* Event name */
  87         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  88                 goto no_match;
  89         }
  90         /* Match. */
  91         return 1;
  92
  93 no_match:
  94         return 0;
  95 }
  96
  97 /*
  98  * Match function for the events hash table lookup by name and loglevel.
  99  */
 100 static int ht_match_event(struct cds_lfht_node *node,
 101                 const void *_key)
 102 {
 103         struct agent_event *event;
 104         const struct agent_ht_key *key;
 105         int ll_match;
 106
 107         assert(node);
 108         assert(_key);
 109
 110         event = caa_container_of(node, struct agent_event, node.node);
 111         key = _key;
 112
 113         /* Match 2 elements of the key: name and loglevel. */
 114
 115         /* Event name */
 116         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
 117                 goto no_match;
 118         }
 119
 120         /* Event loglevel value and type. */
 121         ll_match = loglevels_match(event->loglevel_type,
 122                 event->loglevel_value, key->loglevel_type,
 123                 key->loglevel_value, LTTNG_EVENT_LOGLEVEL_ALL);
 124
 125         if (!ll_match) {
 126                 goto no_match;
 127         }
 128
 129         return 1;
 130
 131 no_match:
 132         return 0;
 133 }
 134
 135 /*
 136  * Add unique agent event based on the event name and loglevel.
 137  */
 138 static void add_unique_agent_event(struct lttng_ht *ht,
 139                 struct agent_event *event)
 140 {
 141         struct cds_lfht_node *node_ptr;
 142         struct agent_ht_key key;
 143
 144         assert(ht);
 145         assert(ht->ht);
 146         assert(event);
 147
 148         key.name = event->name;
 149         key.loglevel_value = event->loglevel_value;
 150         key.loglevel_type = event->loglevel_type;
 151
 152         node_ptr = cds_lfht_add_unique(ht->ht,
 153                         ht->hash_fct(event->node.key, lttng_ht_seed),
 154                         ht_match_event, &key, &event->node.node);
 155         assert(node_ptr == &event->node.node);
 156 }
 157
 158 /*
 159  * URCU delayed agent event reclaim.
 160  */
 161 static void destroy_event_agent_rcu(struct rcu_head *head)
 162 {
 163         struct lttng_ht_node_str *node =
 164                 caa_container_of(head, struct lttng_ht_node_str, head);
 165         struct agent_event *event =
 166                 caa_container_of(node, struct agent_event, node);
 167
 168         agent_destroy_event(event);
 169 }
 170
 171 /*
 172  * URCU delayed agent app reclaim.
 173  */
 174 static void destroy_app_agent_rcu(struct rcu_head *head)
 175 {
 176         struct lttng_ht_node_ulong *node =
 177                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 178         struct agent_app *app =
 179                 caa_container_of(node, struct agent_app, node);
 180
 181         free(app);
 182 }
 183
 184 /*
 185  * Communication with the agent. Send the message header to the given socket in
 186  * big endian.
 187  *
 188  * Return 0 on success or else a negative errno message of sendmsg() op.
 189  */
 190 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
 191                 uint32_t cmd, uint32_t cmd_version)
 192 {
 193         int ret;
 194         ssize_t size;
 195         struct lttcomm_agent_hdr msg;
 196
 197         assert(sock);
 198
 199         memset(&msg, 0, sizeof(msg));
 200         msg.data_size = htobe64(data_size);
 201         msg.cmd = htobe32(cmd);
 202         msg.cmd_version = htobe32(cmd_version);
 203
 204         size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
 205         if (size < sizeof(msg)) {
 206                 ret = -errno;
 207                 goto error;
 208         }
 209         ret = 0;
 210
 211 error:
 212         return ret;
 213 }
 214
 215 /*
 216  * Communication call with the agent. Send the payload to the given socket. The
 217  * header MUST be sent prior to this call.
 218  *
 219  * Return 0 on success or else a negative errno value of sendmsg() op.
 220  */
 221 static int send_payload(struct lttcomm_sock *sock, void *data,
 222                 size_t size)
 223 {
 224         int ret;
 225         ssize_t len;
 226
 227         assert(sock);
 228         assert(data);
 229
 230         len = sock->ops->sendmsg(sock, data, size, 0);
 231         if (len < size) {
 232                 ret = -errno;
 233                 goto error;
 234         }
 235         ret = 0;
 236
 237 error:
 238         return ret;
 239 }
 240
 241 /*
 242  * Communication call with the agent. Receive reply from the agent using the
 243  * given socket.
 244  *
 245  * Return 0 on success or else a negative errno value from recvmsg() op.
 246  */
 247 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
 248 {
 249         int ret;
 250         ssize_t len;
 251
 252         assert(sock);
 253         assert(buf);
 254
 255         len = sock->ops->recvmsg(sock, buf, size, 0);
 256         if (len < size) {
 257                 ret = -errno;
 258                 goto error;
 259         }
 260         ret = 0;
 261
 262 error:
 263         return ret;
 264 }
 265
 266 /*
 267  * Internal event listing for a given app. Populate events.
 268  *
 269  * Return number of element in the list or else a negative LTTNG_ERR* code.
 270  * On success, the caller is responsible for freeing the memory
 271  * allocated for "events".
 272  */
 273 static ssize_t list_events(struct agent_app *app, struct lttng_event **events)
 274 {
 275         int ret, i, len = 0, offset = 0;
 276         uint32_t nb_event;
 277         size_t data_size;
 278         uint32_t reply_ret_code;
 279         struct lttng_event *tmp_events = NULL;
 280         struct lttcomm_agent_list_reply *reply = NULL;
 281         struct lttcomm_agent_list_reply_hdr reply_hdr;
 282
 283         assert(app);
 284         assert(app->sock);
 285         assert(events);
 286
 287         DBG2("Agent listing events for app pid: %d and socket %d", app->pid,
 288                         app->sock->fd);
 289
 290         ret = send_header(app->sock, 0, AGENT_CMD_LIST, 0);
 291         if (ret < 0) {
 292                 goto error_io;
 293         }
 294
 295         /* Get list header so we know how much we'll receive. */
 296         ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
 297         if (ret < 0) {
 298                 goto error_io;
 299         }
 300
 301         reply_ret_code = be32toh(reply_hdr.ret_code);
 302         log_reply_code(reply_ret_code);
 303         switch (reply_ret_code) {
 304         case AGENT_RET_CODE_SUCCESS:
 305                 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
 306                 break;
 307         default:
 308                 ret = LTTNG_ERR_UNK;
 309                 goto error;
 310         }
 311
 312         reply = zmalloc(data_size);
 313         if (!reply) {
 314                 ret = LTTNG_ERR_NOMEM;
 315                 goto error;
 316         }
 317
 318         /* Get the list with the appropriate data size. */
 319         ret = recv_reply(app->sock, reply, data_size);
 320         if (ret < 0) {
 321                 goto error_io;
 322         }
 323
 324         nb_event = be32toh(reply->nb_event);
 325         tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
 326         if (!tmp_events) {
 327                 ret = LTTNG_ERR_NOMEM;
 328                 goto error;
 329         }
 330
 331         for (i = 0; i < nb_event; i++) {
 332                 offset += len;
 333                 strncpy(tmp_events[i].name, reply->payload + offset,
 334                                 sizeof(tmp_events[i].name));
 335                 tmp_events[i].pid = app->pid;
 336                 tmp_events[i].enabled = -1;
 337                 len = strlen(reply->payload + offset) + 1;
 338         }
 339
 340         *events = tmp_events;
 341
 342         free(reply);
 343         return nb_event;
 344
 345 error_io:
 346         ret = LTTNG_ERR_UST_LIST_FAIL;
 347 error:
 348         free(reply);
 349         free(tmp_events);
 350         return -ret;
 351
 352 }
 353
 354 /*
 355  * Internal enable agent event on a agent application. This function
 356  * communicates with the agent to enable a given event.
 357  *
 358  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 359  */
 360 static int enable_event(struct agent_app *app, struct agent_event *event)
 361 {
 362         int ret;
 363         uint64_t data_size;
 364         uint32_t reply_ret_code;
 365         struct lttcomm_agent_enable msg;
 366         struct lttcomm_agent_generic_reply reply;
 367
 368         assert(app);
 369         assert(app->sock);
 370         assert(event);
 371
 372         DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
 373                         app->pid, app->sock->fd);
 374
 375         data_size = sizeof(msg);
 376
 377         ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
 378         if (ret < 0) {
 379                 goto error_io;
 380         }
 381
 382         memset(&msg, 0, sizeof(msg));
 383         msg.loglevel_value = event->loglevel_value;
 384         msg.loglevel_type = event->loglevel_type;
 385         strncpy(msg.name, event->name, sizeof(msg.name));
 386         ret = send_payload(app->sock, &msg, sizeof(msg));
 387         if (ret < 0) {
 388                 goto error_io;
 389         }
 390
 391         ret = recv_reply(app->sock, &reply, sizeof(reply));
 392         if (ret < 0) {
 393                 goto error_io;
 394         }
 395
 396         reply_ret_code = be32toh(reply.ret_code);
 397         log_reply_code(reply_ret_code);
 398         switch (reply_ret_code) {
 399         case AGENT_RET_CODE_SUCCESS:
 400                 break;
 401         case AGENT_RET_CODE_UNKNOWN_NAME:
 402                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 403                 goto error;
 404         default:
 405                 ret = LTTNG_ERR_UNK;
 406                 goto error;
 407         }
 408
 409         return LTTNG_OK;
 410
 411 error_io:
 412         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 413 error:
 414         return ret;
 415 }
 416
 417 /*
 418  * Internal disable agent event call on a agent application. This function
 419  * communicates with the agent to disable a given event.
 420  *
 421  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 422  */
 423 static int disable_event(struct agent_app *app, struct agent_event *event)
 424 {
 425         int ret;
 426         uint64_t data_size;
 427         uint32_t reply_ret_code;
 428         struct lttcomm_agent_disable msg;
 429         struct lttcomm_agent_generic_reply reply;
 430
 431         assert(app);
 432         assert(app->sock);
 433         assert(event);
 434
 435         DBG2("Agent disabling event %s for app pid: %d and socket %d", event->name,
 436                         app->pid, app->sock->fd);
 437
 438         data_size = sizeof(msg);
 439
 440         ret = send_header(app->sock, data_size, AGENT_CMD_DISABLE, 0);
 441         if (ret < 0) {
 442                 goto error_io;
 443         }
 444
 445         memset(&msg, 0, sizeof(msg));
 446         strncpy(msg.name, event->name, sizeof(msg.name));
 447         ret = send_payload(app->sock, &msg, sizeof(msg));
 448         if (ret < 0) {
 449                 goto error_io;
 450         }
 451
 452         ret = recv_reply(app->sock, &reply, sizeof(reply));
 453         if (ret < 0) {
 454                 goto error_io;
 455         }
 456
 457         reply_ret_code = be32toh(reply.ret_code);
 458         log_reply_code(reply_ret_code);
 459         switch (reply_ret_code) {
 460         case AGENT_RET_CODE_SUCCESS:
 461                 break;
 462         case AGENT_RET_CODE_UNKNOWN_NAME:
 463                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 464                 goto error;
 465         default:
 466                 ret = LTTNG_ERR_UNK;
 467                 goto error;
 468         }
 469
 470         return LTTNG_OK;
 471
 472 error_io:
 473         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 474 error:
 475         return ret;
 476 }
 477
 478 /*
 479  * Send back the registration DONE command to a given agent application.
 480  *
 481  * Return 0 on success or else a negative value.
 482  */
 483 int agent_send_registration_done(struct agent_app *app)
 484 {
 485         assert(app);
 486         assert(app->sock);
 487
 488         DBG("Agent sending registration done to app socket %d", app->sock->fd);
 489
 490         return send_header(app->sock, 0, AGENT_CMD_REG_DONE, 0);
 491 }
 492
 493 /*
 494  * Enable agent event on every agent applications registered with the session
 495  * daemon.
 496  *
 497  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 498  */
 499 int agent_enable_event(struct agent_event *event,
 500                 enum lttng_domain_type domain)
 501 {
 502         int ret;
 503         struct agent_app *app;
 504         struct lttng_ht_iter iter;
 505
 506         assert(event);
 507
 508         rcu_read_lock();
 509
 510         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 511                         node.node) {
 512                 if (app->domain != domain) {
 513                         continue;
 514                 }
 515
 516                 /* Enable event on agent application through TCP socket. */
 517                 ret = enable_event(app, event);
 518                 if (ret != LTTNG_OK) {
 519                         goto error;
 520                 }
 521         }
 522
 523         event->enabled = 1;
 524         ret = LTTNG_OK;
 525
 526 error:
 527         rcu_read_unlock();
 528         return ret;
 529 }
 530
 531 /*
 532  * Disable agent event on every agent applications registered with the session
 533  * daemon.
 534  *
 535  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 536  */
 537 int agent_disable_event(struct agent_event *event,
 538                 enum lttng_domain_type domain)
 539 {
 540         int ret = LTTNG_OK;
 541         struct agent_app *app;
 542         struct lttng_ht_iter iter;
 543
 544         assert(event);
 545         if (!event->enabled) {
 546                 goto end;
 547         }
 548
 549         rcu_read_lock();
 550
 551         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 552                         node.node) {
 553                 if (app->domain != domain) {
 554                         continue;
 555                 }
 556
 557                 /* Enable event on agent application through TCP socket. */
 558                 ret = disable_event(app, event);
 559                 if (ret != LTTNG_OK) {
 560                         goto error;
 561                 }
 562         }
 563
 564         event->enabled = 0;
 565
 566 error:
 567         rcu_read_unlock();
 568 end:
 569         return ret;
 570 }
 571
 572 /*
 573  * Ask every agent for the list of possible event. Events is allocated with the
 574  * events of every agent application.
 575  *
 576  * Return the number of events or else a negative value.
 577  */
 578 int agent_list_events(struct lttng_event **events,
 579                 enum lttng_domain_type domain)
 580 {
 581         int ret;
 582         size_t nbmem, count = 0;
 583         struct agent_app *app;
 584         struct lttng_event *tmp_events = NULL;
 585         struct lttng_ht_iter iter;
 586
 587         assert(events);
 588
 589         DBG2("Agent listing events for domain %d", domain);
 590
 591         nbmem = UST_APP_EVENT_LIST_SIZE;
 592         tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
 593         if (!tmp_events) {
 594                 PERROR("zmalloc agent list events");
 595                 ret = -ENOMEM;
 596                 goto error;
 597         }
 598
 599         rcu_read_lock();
 600         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 601                         node.node) {
 602                 ssize_t nb_ev;
 603                 struct lttng_event *agent_events;
 604
 605                 /* Skip domain not asked by the list. */
 606                 if (app->domain != domain) {
 607                         continue;
 608                 }
 609
 610                 nb_ev = list_events(app, &agent_events);
 611                 if (nb_ev < 0) {
 612                         ret = nb_ev;
 613                         goto error_unlock;
 614                 }
 615
 616                 if (count + nb_ev > nbmem) {
 617                         /* In case the realloc fails, we free the memory */
 618                         struct lttng_event *new_tmp_events;
 619                         size_t new_nbmem;
 620
 621                         new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
 622                         DBG2("Reallocating agent event list from %zu to %zu entries",
 623                                         nbmem, new_nbmem);
 624                         new_tmp_events = realloc(tmp_events,
 625                                 new_nbmem * sizeof(*new_tmp_events));
 626                         if (!new_tmp_events) {
 627                                 PERROR("realloc agent events");
 628                                 ret = -ENOMEM;
 629                                 free(agent_events);
 630                                 goto error_unlock;
 631                         }
 632                         /* Zero the new memory */
 633                         memset(new_tmp_events + nbmem, 0,
 634                                 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
 635                         nbmem = new_nbmem;
 636                         tmp_events = new_tmp_events;
 637                 }
 638                 memcpy(tmp_events + count, agent_events,
 639                         nb_ev * sizeof(*tmp_events));
 640                 free(agent_events);
 641                 count += nb_ev;
 642         }
 643         rcu_read_unlock();
 644
 645         ret = count;
 646         *events = tmp_events;
 647         return ret;
 648
 649 error_unlock:
 650         rcu_read_unlock();
 651 error:
 652         free(tmp_events);
 653         return ret;
 654 }
 655
 656 /*
 657  * Create a agent app object using the given PID.
 658  *
 659  * Return newly allocated object or else NULL on error.
 660  */
 661 struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
 662                 struct lttcomm_sock *sock)
 663 {
 664         struct agent_app *app;
 665
 666         assert(sock);
 667
 668         app = zmalloc(sizeof(*app));
 669         if (!app) {
 670                 PERROR("zmalloc agent create");
 671                 goto error;
 672         }
 673
 674         app->pid = pid;
 675         app->domain = domain;
 676         app->sock = sock;
 677         lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
 678
 679 error:
 680         return app;
 681 }
 682
 683 /*
 684  * Lookup agent app by socket in the global hash table.
 685  *
 686  * RCU read side lock MUST be acquired.
 687  *
 688  * Return object if found else NULL.
 689  */
 690 struct agent_app *agent_find_app_by_sock(int sock)
 691 {
 692         struct lttng_ht_node_ulong *node;
 693         struct lttng_ht_iter iter;
 694         struct agent_app *app;
 695
 696         assert(sock >= 0);
 697
 698         lttng_ht_lookup(agent_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
 699         node = lttng_ht_iter_get_node_ulong(&iter);
 700         if (node == NULL) {
 701                 goto error;
 702         }
 703         app = caa_container_of(node, struct agent_app, node);
 704
 705         DBG3("Agent app pid %d found by sock %d.", app->pid, sock);
 706         return app;
 707
 708 error:
 709         DBG3("Agent app NOT found by sock %d.", sock);
 710         return NULL;
 711 }
 712
 713 /*
 714  * Add agent application object to the global hash table.
 715  */
 716 void agent_add_app(struct agent_app *app)
 717 {
 718         assert(app);
 719
 720         DBG3("Agent adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
 721         lttng_ht_add_unique_ulong(agent_apps_ht_by_sock, &app->node);
 722 }
 723
 724 /*
 725  * Delete agent application from the global hash table.
 726  *
 727  * rcu_read_lock() must be held by the caller.
 728  */
 729 void agent_delete_app(struct agent_app *app)
 730 {
 731         int ret;
 732         struct lttng_ht_iter iter;
 733
 734         assert(app);
 735
 736         DBG3("Agent deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
 737
 738         iter.iter.node = &app->node.node;
 739         ret = lttng_ht_del(agent_apps_ht_by_sock, &iter);
 740         assert(!ret);
 741 }
 742
 743 /*
 744  * Destroy an agent application object by detaching it from its corresponding
 745  * UST app if one is connected by closing the socket. Finally, perform a
 746  * delayed memory reclaim.
 747  */
 748 void agent_destroy_app(struct agent_app *app)
 749 {
 750         assert(app);
 751
 752         if (app->sock) {
 753                 app->sock->ops->close(app->sock);
 754                 lttcomm_destroy_sock(app->sock);
 755         }
 756
 757         call_rcu(&app->node.head, destroy_app_agent_rcu);
 758 }
 759
 760 /*
 761  * Initialize an already allocated agent object.
 762  *
 763  * Return 0 on success or else a negative errno value.
 764  */
 765 int agent_init(struct agent *agt)
 766 {
 767         int ret;
 768
 769         assert(agt);
 770
 771         agt->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 772         if (!agt->events) {
 773                 ret = -ENOMEM;
 774                 goto error;
 775         }
 776         lttng_ht_node_init_u64(&agt->node, agt->domain);
 777
 778         return 0;
 779
 780 error:
 781         return ret;
 782 }
 783
 784 /*
 785  * Add agent object to the given hash table.
 786  */
 787 void agent_add(struct agent *agt, struct lttng_ht *ht)
 788 {
 789         assert(agt);
 790         assert(ht);
 791
 792         DBG3("Agent adding from domain %d", agt->domain);
 793
 794         lttng_ht_add_unique_u64(ht, &agt->node);
 795 }
 796
 797 /*
 798  * Create an agent object for the given domain.
 799  *
 800  * Return the allocated agent or NULL on error.
 801  */
 802 struct agent *agent_create(enum lttng_domain_type domain)
 803 {
 804         int ret;
 805         struct agent *agt;
 806
 807         agt = zmalloc(sizeof(struct agent));
 808         if (!agt) {
 809                 goto error;
 810         }
 811         agt->domain = domain;
 812
 813         ret = agent_init(agt);
 814         if (ret < 0) {
 815                 free(agt);
 816                 agt = NULL;
 817                 goto error;
 818         }
 819
 820 error:
 821         return agt;
 822 }
 823
 824 /*
 825  * Create a newly allocated agent event data structure.
 826  * Ownership of filter_expression is taken.
 827  *
 828  * Return a new object else NULL on error.
 829  */
 830 struct agent_event *agent_create_event(const char *name,
 831                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 832                 struct lttng_filter_bytecode *filter, char *filter_expression)
 833 {
 834         struct agent_event *event = NULL;
 835
 836         DBG3("Agent create new event with name %s, loglevel type %d and loglevel value %d",
 837                 name, loglevel_type, loglevel_value);
 838
 839         if (!name) {
 840                 ERR("Failed to create agent event; no name provided.");
 841                 goto error;
 842         }
 843
 844         event = zmalloc(sizeof(*event));
 845         if (!event) {
 846                 goto error;
 847         }
 848
 849         strncpy(event->name, name, sizeof(event->name));
 850         event->name[sizeof(event->name) - 1] = '\0';
 851         lttng_ht_node_init_str(&event->node, event->name);
 852
 853         event->loglevel_value = loglevel_value;
 854         event->loglevel_type = loglevel_type;
 855         event->filter = filter;
 856         event->filter_expression = filter_expression;
 857 error:
 858         return event;
 859 }
 860
 861 /*
 862  * Unique add of a agent event to an agent object.
 863  */
 864 void agent_add_event(struct agent_event *event, struct agent *agt)
 865 {
 866         assert(event);
 867         assert(agt);
 868         assert(agt->events);
 869
 870         DBG3("Agent adding event %s", event->name);
 871         add_unique_agent_event(agt->events, event);
 872         agt->being_used = 1;
 873 }
 874
 875 /*
 876  * Find multiple agent events sharing the given name.
 877  *
 878  * RCU read side lock MUST be acquired. It must be held for the
 879  * duration of the iteration.
 880  *
 881  * Sets the given iterator.
 882  */
 883 void agent_find_events_by_name(const char *name, struct agent *agt,
 884                 struct lttng_ht_iter* iter)
 885 {
 886         struct lttng_ht *ht;
 887         struct agent_ht_key key;
 888
 889         assert(name);
 890         assert(agt);
 891         assert(agt->events);
 892         assert(iter);
 893
 894         ht = agt->events;
 895         key.name = name;
 896
 897         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 898                         ht_match_event_by_name, &key, &iter->iter);
 899 }
 900
 901 /*
 902  * Get the next agent event duplicate by name. This should be called
 903  * after a call to agent_find_events_by_name() to iterate on events.
 904  *
 905  * The RCU read lock must be held during the iteration and for as long
 906  * as the object the iterator points to remains in use.
 907  */
 908 void agent_event_next_duplicate(const char *name,
 909                 struct agent *agt, struct lttng_ht_iter* iter)
 910 {
 911         struct agent_ht_key key;
 912
 913         key.name = name;
 914
 915         cds_lfht_next_duplicate(agt->events->ht, ht_match_event_by_name,
 916                 &key, &iter->iter);
 917 }
 918
 919 /*
 920  * Find a agent event in the given agent using name and loglevel.
 921  *
 922  * RCU read side lock MUST be acquired. It must be kept for as long as
 923  * the returned agent_event is used.
 924  *
 925  * Return object if found else NULL.
 926  */
 927 struct agent_event *agent_find_event(const char *name,
 928                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 929                 struct agent *agt)
 930 {
 931         struct lttng_ht_node_str *node;
 932         struct lttng_ht_iter iter;
 933         struct lttng_ht *ht;
 934         struct agent_ht_key key;
 935
 936         assert(name);
 937         assert(agt);
 938         assert(agt->events);
 939
 940         ht = agt->events;
 941         key.name = name;
 942         key.loglevel_value = loglevel_value;
 943         key.loglevel_type = loglevel_type;
 944
 945         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 946                         ht_match_event, &key, &iter.iter);
 947         node = lttng_ht_iter_get_node_str(&iter);
 948         if (node == NULL) {
 949                 goto error;
 950         }
 951
 952         DBG3("Agent event found %s.", name);
 953         return caa_container_of(node, struct agent_event, node);
 954
 955 error:
 956         DBG3("Agent event NOT found %s.", name);
 957         return NULL;
 958 }
 959
 960 /*
 961  * Free given agent event. This event must not be globally visible at this
 962  * point (only expected to be used on failure just after event creation). After
 963  * this call, the pointer is not usable anymore.
 964  */
 965 void agent_destroy_event(struct agent_event *event)
 966 {
 967         assert(event);
 968
 969         free(event->filter);
 970         free(event->filter_expression);
 971         free(event->exclusion);
 972         free(event);
 973 }
 974
 975 /*
 976  * Destroy an agent completely.
 977  */
 978 void agent_destroy(struct agent *agt)
 979 {
 980         struct lttng_ht_node_str *node;
 981         struct lttng_ht_iter iter;
 982
 983         assert(agt);
 984
 985         DBG3("Agent destroy");
 986
 987         rcu_read_lock();
 988         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, node, node) {
 989                 int ret;
 990                 struct agent_event *event;
 991
 992                 /*
 993                  * When destroying an event, we have to try to disable it on the agent
 994                  * side so the event stops generating data. The return value is not
 995                  * important since we have to continue anyway destroying the object.
 996                  */
 997                 event = caa_container_of(node, struct agent_event, node);
 998                 (void) agent_disable_event(event, agt->domain);
 999
1000                 ret = lttng_ht_del(agt->events, &iter);
1001                 assert(!ret);
1002                 call_rcu(&node->head, destroy_event_agent_rcu);
1003         }
1004         rcu_read_unlock();
1005
1006         ht_cleanup_push(agt->events);
1007         free(agt);
1008 }
1009
1010 /*
1011  * Allocate agent_apps_ht_by_sock.
1012  */
1013 int agent_app_ht_alloc(void)
1014 {
1015         int ret = 0;
1016
1017         agent_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1018         if (!agent_apps_ht_by_sock) {
1019                 ret = -1;
1020         }
1021
1022         return ret;
1023 }
1024
1025 /*
1026  * Destroy a agent application by socket.
1027  */
1028 void agent_destroy_app_by_sock(int sock)
1029 {
1030         struct agent_app *app;
1031
1032         assert(sock >= 0);
1033
1034         /*
1035          * Not finding an application is a very important error that should NEVER
1036          * happen. The hash table deletion is ONLY done through this call when the
1037          * main sessiond thread is torn down.
1038          */
1039         rcu_read_lock();
1040         app = agent_find_app_by_sock(sock);
1041         assert(app);
1042
1043         /* RCU read side lock is assumed to be held by this function. */
1044         agent_delete_app(app);
1045
1046         /* The application is freed in a RCU call but the socket is closed here. */
1047         agent_destroy_app(app);
1048         rcu_read_unlock();
1049 }
1050
1051 /*
1052  * Clean-up the agent app hash table and destroy it.
1053  */
1054 void agent_app_ht_clean(void)
1055 {
1056         struct lttng_ht_node_ulong *node;
1057         struct lttng_ht_iter iter;
1058
1059         if (!agent_apps_ht_by_sock) {
1060                 return;
1061         }
1062         rcu_read_lock();
1063         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) {
1064                 struct agent_app *app;
1065
1066                 app = caa_container_of(node, struct agent_app, node);
1067                 agent_destroy_app_by_sock(app->sock->fd);
1068         }
1069         rcu_read_unlock();
1070
1071         lttng_ht_destroy(agent_apps_ht_by_sock);
1072 }
1073
1074 /*
1075  * Update a agent application (given socket) using the given agent.
1076  *
1077  * Note that this function is most likely to be used with a tracing session
1078  * thus the caller should make sure to hold the appropriate lock(s).
1079  */
1080 void agent_update(struct agent *agt, int sock)
1081 {
1082         int ret;
1083         struct agent_app *app;
1084         struct agent_event *event;
1085         struct lttng_ht_iter iter;
1086
1087         assert(agt);
1088         assert(sock >= 0);
1089
1090         DBG("Agent updating app socket %d", sock);
1091
1092         rcu_read_lock();
1093         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
1094                 /* Skip event if disabled. */
1095                 if (!event->enabled) {
1096                         continue;
1097                 }
1098
1099                 app = agent_find_app_by_sock(sock);
1100                 /*
1101                  * We are in the registration path thus if the application is gone,
1102                  * there is a serious code flow error.
1103                  */
1104                 assert(app);
1105
1106                 ret = enable_event(app, event);
1107                 if (ret != LTTNG_OK) {
1108                         DBG2("Agent update unable to enable event %s on app pid: %d sock %d",
1109                                         event->name, app->pid, app->sock->fd);
1110                         /* Let's try the others here and don't assume the app is dead. */
1111                         continue;
1112                 }
1113         }
1114         rcu_read_unlock();
1115 }