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