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 #include "error.h"
  32
  33 #define AGENT_RET_CODE_INDEX(code) (code - AGENT_RET_CODE_SUCCESS)
  34
  35 /*
  36  * Human readable agent return code.
  37  */
  38 static const char *error_string_array[] = {
  39         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_SUCCESS) ] = "Success",
  40         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_INVALID) ] = "Invalid command",
  41         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_UNKNOWN_NAME) ] = "Unknown logger name",
  42
  43         /* Last element */
  44         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_NR) ] = "Unknown code",
  45 };
  46
  47 static
  48 void log_reply_code(uint32_t in_reply_ret_code)
  49 {
  50         int level = PRINT_DBG3;
  51         /*
  52          * reply_ret_code and in_reply_ret_code are kept separate to have a
  53          * sanitized value (used to retrieve the human readable string) and the
  54          * original value which is logged as-is.
  55          */
  56         uint32_t reply_ret_code = in_reply_ret_code;
  57
  58         if (reply_ret_code < AGENT_RET_CODE_SUCCESS ||
  59                         reply_ret_code >= AGENT_RET_CODE_NR) {
  60                 reply_ret_code = AGENT_RET_CODE_NR;
  61                 level = PRINT_ERR;
  62         }
  63
  64         LOG(level, "Agent replied with retcode: %s (%"PRIu32")",
  65                         error_string_array[AGENT_RET_CODE_INDEX(
  66                         reply_ret_code)],
  67                         in_reply_ret_code);
  68 }
  69
  70 /*
  71  * Match function for the events hash table lookup by name.
  72  */
  73 static int ht_match_event_by_name(struct cds_lfht_node *node,
  74                 const void *_key)
  75 {
  76         struct agent_event *event;
  77         const struct agent_ht_key *key;
  78
  79         assert(node);
  80         assert(_key);
  81
  82         event = caa_container_of(node, struct agent_event, node.node);
  83         key = _key;
  84
  85         /* Match 1 elements of the key: name. */
  86
  87         /* Event name */
  88         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  89                 goto no_match;
  90         }
  91         /* Match. */
  92         return 1;
  93
  94 no_match:
  95         return 0;
  96 }
  97
  98 /*
  99  * Match function for the events hash table lookup by name and loglevel.
 100  */
 101 static int ht_match_event(struct cds_lfht_node *node,
 102                 const void *_key)
 103 {
 104         struct agent_event *event;
 105         const struct agent_ht_key *key;
 106         int ll_match;
 107
 108         assert(node);
 109         assert(_key);
 110
 111         event = caa_container_of(node, struct agent_event, node.node);
 112         key = _key;
 113
 114         /* Match 2 elements of the key: name and loglevel. */
 115
 116         /* Event name */
 117         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
 118                 goto no_match;
 119         }
 120
 121         /* Event loglevel value and type. */
 122         ll_match = loglevels_match(event->loglevel_type,
 123                 event->loglevel_value, key->loglevel_type,
 124                 key->loglevel_value, LTTNG_EVENT_LOGLEVEL_ALL);
 125
 126         if (!ll_match) {
 127                 goto no_match;
 128         }
 129
 130         return 1;
 131
 132 no_match:
 133         return 0;
 134 }
 135
 136 /*
 137  * Add unique agent event based on the event name and loglevel.
 138  */
 139 static void add_unique_agent_event(struct lttng_ht *ht,
 140                 struct agent_event *event)
 141 {
 142         struct cds_lfht_node *node_ptr;
 143         struct agent_ht_key key;
 144
 145         assert(ht);
 146         assert(ht->ht);
 147         assert(event);
 148
 149         key.name = event->name;
 150         key.loglevel_value = event->loglevel_value;
 151         key.loglevel_type = event->loglevel_type;
 152
 153         node_ptr = cds_lfht_add_unique(ht->ht,
 154                         ht->hash_fct(event->node.key, lttng_ht_seed),
 155                         ht_match_event, &key, &event->node.node);
 156         assert(node_ptr == &event->node.node);
 157 }
 158
 159 /*
 160  * URCU delayed agent event reclaim.
 161  */
 162 static void destroy_event_agent_rcu(struct rcu_head *head)
 163 {
 164         struct lttng_ht_node_str *node =
 165                 caa_container_of(head, struct lttng_ht_node_str, head);
 166         struct agent_event *event =
 167                 caa_container_of(node, struct agent_event, node);
 168
 169         agent_destroy_event(event);
 170 }
 171
 172 /*
 173  * URCU delayed agent app reclaim.
 174  */
 175 static void destroy_app_agent_rcu(struct rcu_head *head)
 176 {
 177         struct lttng_ht_node_ulong *node =
 178                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 179         struct agent_app *app =
 180                 caa_container_of(node, struct agent_app, node);
 181
 182         free(app);
 183 }
 184
 185 /*
 186  * Communication with the agent. Send the message header to the given socket in
 187  * big endian.
 188  *
 189  * Return 0 on success or else a negative errno message of sendmsg() op.
 190  */
 191 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
 192                 uint32_t cmd, uint32_t cmd_version)
 193 {
 194         int ret;
 195         ssize_t size;
 196         struct lttcomm_agent_hdr msg;
 197
 198         assert(sock);
 199
 200         memset(&msg, 0, sizeof(msg));
 201         msg.data_size = htobe64(data_size);
 202         msg.cmd = htobe32(cmd);
 203         msg.cmd_version = htobe32(cmd_version);
 204
 205         size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
 206         if (size < sizeof(msg)) {
 207                 ret = -errno;
 208                 goto error;
 209         }
 210         ret = 0;
 211
 212 error:
 213         return ret;
 214 }
 215
 216 /*
 217  * Communication call with the agent. Send the payload to the given socket. The
 218  * header MUST be sent prior to this call.
 219  *
 220  * Return 0 on success or else a negative errno value of sendmsg() op.
 221  */
 222 static int send_payload(struct lttcomm_sock *sock, void *data,
 223                 size_t size)
 224 {
 225         int ret;
 226         ssize_t len;
 227
 228         assert(sock);
 229         assert(data);
 230
 231         len = sock->ops->sendmsg(sock, data, size, 0);
 232         if (len < size) {
 233                 ret = -errno;
 234                 goto error;
 235         }
 236         ret = 0;
 237
 238 error:
 239         return ret;
 240 }
 241
 242 /*
 243  * Communication call with the agent. Receive reply from the agent using the
 244  * given socket.
 245  *
 246  * Return 0 on success or else a negative errno value from recvmsg() op.
 247  */
 248 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
 249 {
 250         int ret;
 251         ssize_t len;
 252
 253         assert(sock);
 254         assert(buf);
 255
 256         len = sock->ops->recvmsg(sock, buf, size, 0);
 257         if (len < size) {
 258                 ret = -errno;
 259                 goto error;
 260         }
 261         ret = 0;
 262
 263 error:
 264         return ret;
 265 }
 266
 267 /*
 268  * Internal event listing for a given app. Populate events.
 269  *
 270  * Return number of element in the list or else a negative LTTNG_ERR* code.
 271  * On success, the caller is responsible for freeing the memory
 272  * allocated for "events".
 273  */
 274 static ssize_t list_events(struct agent_app *app, struct lttng_event **events)
 275 {
 276         int ret, i, len = 0, offset = 0;
 277         uint32_t nb_event;
 278         size_t data_size;
 279         uint32_t reply_ret_code;
 280         struct lttng_event *tmp_events = NULL;
 281         struct lttcomm_agent_list_reply *reply = NULL;
 282         struct lttcomm_agent_list_reply_hdr reply_hdr;
 283
 284         assert(app);
 285         assert(app->sock);
 286         assert(events);
 287
 288         DBG2("Agent listing events for app pid: %d and socket %d", app->pid,
 289                         app->sock->fd);
 290
 291         ret = send_header(app->sock, 0, AGENT_CMD_LIST, 0);
 292         if (ret < 0) {
 293                 goto error_io;
 294         }
 295
 296         /* Get list header so we know how much we'll receive. */
 297         ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
 298         if (ret < 0) {
 299                 goto error_io;
 300         }
 301
 302         reply_ret_code = be32toh(reply_hdr.ret_code);
 303         log_reply_code(reply_ret_code);
 304         switch (reply_ret_code) {
 305         case AGENT_RET_CODE_SUCCESS:
 306                 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
 307                 break;
 308         default:
 309                 ret = LTTNG_ERR_UNK;
 310                 goto error;
 311         }
 312
 313         reply = zmalloc(data_size);
 314         if (!reply) {
 315                 ret = LTTNG_ERR_NOMEM;
 316                 goto error;
 317         }
 318
 319         /* Get the list with the appropriate data size. */
 320         ret = recv_reply(app->sock, reply, data_size);
 321         if (ret < 0) {
 322                 goto error_io;
 323         }
 324
 325         nb_event = be32toh(reply->nb_event);
 326         tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
 327         if (!tmp_events) {
 328                 ret = LTTNG_ERR_NOMEM;
 329                 goto error;
 330         }
 331
 332         for (i = 0; i < nb_event; i++) {
 333                 offset += len;
 334                 strncpy(tmp_events[i].name, reply->payload + offset,
 335                                 sizeof(tmp_events[i].name));
 336                 tmp_events[i].pid = app->pid;
 337                 tmp_events[i].enabled = -1;
 338                 len = strlen(reply->payload + offset) + 1;
 339         }
 340
 341         *events = tmp_events;
 342
 343         free(reply);
 344         return nb_event;
 345
 346 error_io:
 347         ret = LTTNG_ERR_UST_LIST_FAIL;
 348 error:
 349         free(reply);
 350         free(tmp_events);
 351         return -ret;
 352
 353 }
 354
 355 /*
 356  * Internal enable agent event on a agent application. This function
 357  * communicates with the agent to enable a given event.
 358  *
 359  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 360  */
 361 static int enable_event(struct agent_app *app, struct agent_event *event)
 362 {
 363         int ret;
 364         uint64_t data_size;
 365         uint32_t reply_ret_code;
 366         struct lttcomm_agent_enable msg;
 367         struct lttcomm_agent_generic_reply reply;
 368
 369         assert(app);
 370         assert(app->sock);
 371         assert(event);
 372
 373         DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
 374                         app->pid, app->sock->fd);
 375
 376         data_size = sizeof(msg);
 377
 378         ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
 379         if (ret < 0) {
 380                 goto error_io;
 381         }
 382
 383         memset(&msg, 0, sizeof(msg));
 384         msg.loglevel_value = event->loglevel_value;
 385         msg.loglevel_type = event->loglevel_type;
 386         strncpy(msg.name, event->name, sizeof(msg.name));
 387         ret = send_payload(app->sock, &msg, sizeof(msg));
 388         if (ret < 0) {
 389                 goto error_io;
 390         }
 391
 392         ret = recv_reply(app->sock, &reply, sizeof(reply));
 393         if (ret < 0) {
 394                 goto error_io;
 395         }
 396
 397         reply_ret_code = be32toh(reply.ret_code);
 398         log_reply_code(reply_ret_code);
 399         switch (reply_ret_code) {
 400         case AGENT_RET_CODE_SUCCESS:
 401                 break;
 402         case AGENT_RET_CODE_UNKNOWN_NAME:
 403                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 404                 goto error;
 405         default:
 406                 ret = LTTNG_ERR_UNK;
 407                 goto error;
 408         }
 409
 410         return LTTNG_OK;
 411
 412 error_io:
 413         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 414 error:
 415         return ret;
 416 }
 417
 418 /*
 419  * Internal disable agent event call on a agent application. This function
 420  * communicates with the agent to disable a given event.
 421  *
 422  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 423  */
 424 static int disable_event(struct agent_app *app, struct agent_event *event)
 425 {
 426         int ret;
 427         uint64_t data_size;
 428         uint32_t reply_ret_code;
 429         struct lttcomm_agent_disable msg;
 430         struct lttcomm_agent_generic_reply reply;
 431
 432         assert(app);
 433         assert(app->sock);
 434         assert(event);
 435
 436         DBG2("Agent disabling event %s for app pid: %d and socket %d", event->name,
 437                         app->pid, app->sock->fd);
 438
 439         data_size = sizeof(msg);
 440
 441         ret = send_header(app->sock, data_size, AGENT_CMD_DISABLE, 0);
 442         if (ret < 0) {
 443                 goto error_io;
 444         }
 445
 446         memset(&msg, 0, sizeof(msg));
 447         strncpy(msg.name, event->name, sizeof(msg.name));
 448         ret = send_payload(app->sock, &msg, sizeof(msg));
 449         if (ret < 0) {
 450                 goto error_io;
 451         }
 452
 453         ret = recv_reply(app->sock, &reply, sizeof(reply));
 454         if (ret < 0) {
 455                 goto error_io;
 456         }
 457
 458         reply_ret_code = be32toh(reply.ret_code);
 459         log_reply_code(reply_ret_code);
 460         switch (reply_ret_code) {
 461         case AGENT_RET_CODE_SUCCESS:
 462                 break;
 463         case AGENT_RET_CODE_UNKNOWN_NAME:
 464                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 465                 goto error;
 466         default:
 467                 ret = LTTNG_ERR_UNK;
 468                 goto error;
 469         }
 470
 471         return LTTNG_OK;
 472
 473 error_io:
 474         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 475 error:
 476         return ret;
 477 }
 478
 479 /*
 480  * Send back the registration DONE command to a given agent application.
 481  *
 482  * Return 0 on success or else a negative value.
 483  */
 484 int agent_send_registration_done(struct agent_app *app)
 485 {
 486         assert(app);
 487         assert(app->sock);
 488
 489         DBG("Agent sending registration done to app socket %d", app->sock->fd);
 490
 491         return send_header(app->sock, 0, AGENT_CMD_REG_DONE, 0);
 492 }
 493
 494 /*
 495  * Enable agent event on every agent applications registered with the session
 496  * daemon.
 497  *
 498  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 499  */
 500 int agent_enable_event(struct agent_event *event,
 501                 enum lttng_domain_type domain)
 502 {
 503         int ret;
 504         struct agent_app *app;
 505         struct lttng_ht_iter iter;
 506
 507         assert(event);
 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 = enable_event(app, event);
 519                 if (ret != LTTNG_OK) {
 520                         goto error;
 521                 }
 522         }
 523
 524         event->enabled = 1;
 525         ret = LTTNG_OK;
 526
 527 error:
 528         rcu_read_unlock();
 529         return ret;
 530 }
 531
 532 /*
 533  * Disable agent event on every agent applications registered with the session
 534  * daemon.
 535  *
 536  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 537  */
 538 int agent_disable_event(struct agent_event *event,
 539                 enum lttng_domain_type domain)
 540 {
 541         int ret = LTTNG_OK;
 542         struct agent_app *app;
 543         struct lttng_ht_iter iter;
 544
 545         assert(event);
 546         if (!event->enabled) {
 547                 goto end;
 548         }
 549
 550         rcu_read_lock();
 551
 552         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 553                         node.node) {
 554                 if (app->domain != domain) {
 555                         continue;
 556                 }
 557
 558                 /* Enable event on agent application through TCP socket. */
 559                 ret = disable_event(app, event);
 560                 if (ret != LTTNG_OK) {
 561                         goto error;
 562                 }
 563         }
 564
 565         event->enabled = 0;
 566
 567 error:
 568         rcu_read_unlock();
 569 end:
 570         return ret;
 571 }
 572
 573 /*
 574  * Ask every agent for the list of possible event. Events is allocated with the
 575  * events of every agent application.
 576  *
 577  * Return the number of events or else a negative value.
 578  */
 579 int agent_list_events(struct lttng_event **events,
 580                 enum lttng_domain_type domain)
 581 {
 582         int ret;
 583         size_t nbmem, count = 0;
 584         struct agent_app *app;
 585         struct lttng_event *tmp_events = NULL;
 586         struct lttng_ht_iter iter;
 587
 588         assert(events);
 589
 590         DBG2("Agent listing events for domain %d", domain);
 591
 592         nbmem = UST_APP_EVENT_LIST_SIZE;
 593         tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
 594         if (!tmp_events) {
 595                 PERROR("zmalloc agent list events");
 596                 ret = -ENOMEM;
 597                 goto error;
 598         }
 599
 600         rcu_read_lock();
 601         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 602                         node.node) {
 603                 ssize_t nb_ev;
 604                 struct lttng_event *agent_events;
 605
 606                 /* Skip domain not asked by the list. */
 607                 if (app->domain != domain) {
 608                         continue;
 609                 }
 610
 611                 nb_ev = list_events(app, &agent_events);
 612                 if (nb_ev < 0) {
 613                         ret = nb_ev;
 614                         goto error_unlock;
 615                 }
 616
 617                 if (count + nb_ev > nbmem) {
 618                         /* In case the realloc fails, we free the memory */
 619                         struct lttng_event *new_tmp_events;
 620                         size_t new_nbmem;
 621
 622                         new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
 623                         DBG2("Reallocating agent event list from %zu to %zu entries",
 624                                         nbmem, new_nbmem);
 625                         new_tmp_events = realloc(tmp_events,
 626                                 new_nbmem * sizeof(*new_tmp_events));
 627                         if (!new_tmp_events) {
 628                                 PERROR("realloc agent events");
 629                                 ret = -ENOMEM;
 630                                 free(agent_events);
 631                                 goto error_unlock;
 632                         }
 633                         /* Zero the new memory */
 634                         memset(new_tmp_events + nbmem, 0,
 635                                 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
 636                         nbmem = new_nbmem;
 637                         tmp_events = new_tmp_events;
 638                 }
 639                 memcpy(tmp_events + count, agent_events,
 640                         nb_ev * sizeof(*tmp_events));
 641                 free(agent_events);
 642                 count += nb_ev;
 643         }
 644         rcu_read_unlock();
 645
 646         ret = count;
 647         *events = tmp_events;
 648         return ret;
 649
 650 error_unlock:
 651         rcu_read_unlock();
 652 error:
 653         free(tmp_events);
 654         return ret;
 655 }
 656
 657 /*
 658  * Create a agent app object using the given PID.
 659  *
 660  * Return newly allocated object or else NULL on error.
 661  */
 662 struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
 663                 struct lttcomm_sock *sock)
 664 {
 665         struct agent_app *app;
 666
 667         assert(sock);
 668
 669         app = zmalloc(sizeof(*app));
 670         if (!app) {
 671                 PERROR("zmalloc agent create");
 672                 goto error;
 673         }
 674
 675         app->pid = pid;
 676         app->domain = domain;
 677         app->sock = sock;
 678         lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
 679
 680 error:
 681         return app;
 682 }
 683
 684 /*
 685  * Lookup agent app by socket in the global hash table.
 686  *
 687  * RCU read side lock MUST be acquired.
 688  *
 689  * Return object if found else NULL.
 690  */
 691 struct agent_app *agent_find_app_by_sock(int sock)
 692 {
 693         struct lttng_ht_node_ulong *node;
 694         struct lttng_ht_iter iter;
 695         struct agent_app *app;
 696
 697         assert(sock >= 0);
 698
 699         lttng_ht_lookup(agent_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
 700         node = lttng_ht_iter_get_node_ulong(&iter);
 701         if (node == NULL) {
 702                 goto error;
 703         }
 704         app = caa_container_of(node, struct agent_app, node);
 705
 706         DBG3("Agent app pid %d found by sock %d.", app->pid, sock);
 707         return app;
 708
 709 error:
 710         DBG3("Agent app NOT found by sock %d.", sock);
 711         return NULL;
 712 }
 713
 714 /*
 715  * Add agent application object to the global hash table.
 716  */
 717 void agent_add_app(struct agent_app *app)
 718 {
 719         assert(app);
 720
 721         DBG3("Agent adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
 722         lttng_ht_add_unique_ulong(agent_apps_ht_by_sock, &app->node);
 723 }
 724
 725 /*
 726  * Delete agent application from the global hash table.
 727  *
 728  * rcu_read_lock() must be held by the caller.
 729  */
 730 void agent_delete_app(struct agent_app *app)
 731 {
 732         int ret;
 733         struct lttng_ht_iter iter;
 734
 735         assert(app);
 736
 737         DBG3("Agent deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
 738
 739         iter.iter.node = &app->node.node;
 740         ret = lttng_ht_del(agent_apps_ht_by_sock, &iter);
 741         assert(!ret);
 742 }
 743
 744 /*
 745  * Destroy an agent application object by detaching it from its corresponding
 746  * UST app if one is connected by closing the socket. Finally, perform a
 747  * delayed memory reclaim.
 748  */
 749 void agent_destroy_app(struct agent_app *app)
 750 {
 751         assert(app);
 752
 753         if (app->sock) {
 754                 app->sock->ops->close(app->sock);
 755                 lttcomm_destroy_sock(app->sock);
 756         }
 757
 758         call_rcu(&app->node.head, destroy_app_agent_rcu);
 759 }
 760
 761 /*
 762  * Initialize an already allocated agent object.
 763  *
 764  * Return 0 on success or else a negative errno value.
 765  */
 766 int agent_init(struct agent *agt)
 767 {
 768         int ret;
 769
 770         assert(agt);
 771
 772         agt->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 773         if (!agt->events) {
 774                 ret = -ENOMEM;
 775                 goto error;
 776         }
 777         lttng_ht_node_init_u64(&agt->node, agt->domain);
 778
 779         return 0;
 780
 781 error:
 782         return ret;
 783 }
 784
 785 /*
 786  * Add agent object to the given hash table.
 787  */
 788 void agent_add(struct agent *agt, struct lttng_ht *ht)
 789 {
 790         assert(agt);
 791         assert(ht);
 792
 793         DBG3("Agent adding from domain %d", agt->domain);
 794
 795         lttng_ht_add_unique_u64(ht, &agt->node);
 796 }
 797
 798 /*
 799  * Create an agent object for the given domain.
 800  *
 801  * Return the allocated agent or NULL on error.
 802  */
 803 struct agent *agent_create(enum lttng_domain_type domain)
 804 {
 805         int ret;
 806         struct agent *agt;
 807
 808         agt = zmalloc(sizeof(struct agent));
 809         if (!agt) {
 810                 goto error;
 811         }
 812         agt->domain = domain;
 813
 814         ret = agent_init(agt);
 815         if (ret < 0) {
 816                 free(agt);
 817                 agt = NULL;
 818                 goto error;
 819         }
 820
 821 error:
 822         return agt;
 823 }
 824
 825 /*
 826  * Create a newly allocated agent event data structure.
 827  * Ownership of filter_expression is taken.
 828  *
 829  * Return a new object else NULL on error.
 830  */
 831 struct agent_event *agent_create_event(const char *name,
 832                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 833                 struct lttng_filter_bytecode *filter, char *filter_expression)
 834 {
 835         struct agent_event *event = NULL;
 836
 837         DBG3("Agent create new event with name %s, loglevel type %d and loglevel value %d",
 838                 name, loglevel_type, loglevel_value);
 839
 840         if (!name) {
 841                 ERR("Failed to create agent event; no name provided.");
 842                 goto error;
 843         }
 844
 845         event = zmalloc(sizeof(*event));
 846         if (!event) {
 847                 goto error;
 848         }
 849
 850         strncpy(event->name, name, sizeof(event->name));
 851         event->name[sizeof(event->name) - 1] = '\0';
 852         lttng_ht_node_init_str(&event->node, event->name);
 853
 854         event->loglevel_value = loglevel_value;
 855         event->loglevel_type = loglevel_type;
 856         event->filter = filter;
 857         event->filter_expression = filter_expression;
 858 error:
 859         return event;
 860 }
 861
 862 /*
 863  * Unique add of a agent event to an agent object.
 864  */
 865 void agent_add_event(struct agent_event *event, struct agent *agt)
 866 {
 867         assert(event);
 868         assert(agt);
 869         assert(agt->events);
 870
 871         DBG3("Agent adding event %s", event->name);
 872         add_unique_agent_event(agt->events, event);
 873         agt->being_used = 1;
 874 }
 875
 876 /*
 877  * Find multiple agent events sharing the given name.
 878  *
 879  * RCU read side lock MUST be acquired. It must be held for the
 880  * duration of the iteration.
 881  *
 882  * Sets the given iterator.
 883  */
 884 void agent_find_events_by_name(const char *name, struct agent *agt,
 885                 struct lttng_ht_iter* iter)
 886 {
 887         struct lttng_ht *ht;
 888         struct agent_ht_key key;
 889
 890         assert(name);
 891         assert(agt);
 892         assert(agt->events);
 893         assert(iter);
 894
 895         ht = agt->events;
 896         key.name = name;
 897
 898         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 899                         ht_match_event_by_name, &key, &iter->iter);
 900 }
 901
 902 /*
 903  * Get the next agent event duplicate by name. This should be called
 904  * after a call to agent_find_events_by_name() to iterate on events.
 905  *
 906  * The RCU read lock must be held during the iteration and for as long
 907  * as the object the iterator points to remains in use.
 908  */
 909 void agent_event_next_duplicate(const char *name,
 910                 struct agent *agt, struct lttng_ht_iter* iter)
 911 {
 912         struct agent_ht_key key;
 913
 914         key.name = name;
 915
 916         cds_lfht_next_duplicate(agt->events->ht, ht_match_event_by_name,
 917                 &key, &iter->iter);
 918 }
 919
 920 /*
 921  * Find a agent event in the given agent using name and loglevel.
 922  *
 923  * RCU read side lock MUST be acquired. It must be kept for as long as
 924  * the returned agent_event is used.
 925  *
 926  * Return object if found else NULL.
 927  */
 928 struct agent_event *agent_find_event(const char *name,
 929                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 930                 struct agent *agt)
 931 {
 932         struct lttng_ht_node_str *node;
 933         struct lttng_ht_iter iter;
 934         struct lttng_ht *ht;
 935         struct agent_ht_key key;
 936
 937         assert(name);
 938         assert(agt);
 939         assert(agt->events);
 940
 941         ht = agt->events;
 942         key.name = name;
 943         key.loglevel_value = loglevel_value;
 944         key.loglevel_type = loglevel_type;
 945
 946         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 947                         ht_match_event, &key, &iter.iter);
 948         node = lttng_ht_iter_get_node_str(&iter);
 949         if (node == NULL) {
 950                 goto error;
 951         }
 952
 953         DBG3("Agent event found %s.", name);
 954         return caa_container_of(node, struct agent_event, node);
 955
 956 error:
 957         DBG3("Agent event NOT found %s.", name);
 958         return NULL;
 959 }
 960
 961 /*
 962  * Free given agent event. This event must not be globally visible at this
 963  * point (only expected to be used on failure just after event creation). After
 964  * this call, the pointer is not usable anymore.
 965  */
 966 void agent_destroy_event(struct agent_event *event)
 967 {
 968         assert(event);
 969
 970         free(event->filter);
 971         free(event->filter_expression);
 972         free(event->exclusion);
 973         free(event);
 974 }
 975
 976 /*
 977  * Destroy an agent completely.
 978  */
 979 void agent_destroy(struct agent *agt)
 980 {
 981         struct lttng_ht_node_str *node;
 982         struct lttng_ht_iter iter;
 983
 984         assert(agt);
 985
 986         DBG3("Agent destroy");
 987
 988         rcu_read_lock();
 989         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, node, node) {
 990                 int ret;
 991                 struct agent_event *event;
 992
 993                 /*
 994                  * When destroying an event, we have to try to disable it on the agent
 995                  * side so the event stops generating data. The return value is not
 996                  * important since we have to continue anyway destroying the object.
 997                  */
 998                 event = caa_container_of(node, struct agent_event, node);
 999                 (void) agent_disable_event(event, agt->domain);
1000
1001                 ret = lttng_ht_del(agt->events, &iter);
1002                 assert(!ret);
1003                 call_rcu(&node->head, destroy_event_agent_rcu);
1004         }
1005         rcu_read_unlock();
1006
1007         ht_cleanup_push(agt->events);
1008         free(agt);
1009 }
1010
1011 /*
1012  * Allocate agent_apps_ht_by_sock.
1013  */
1014 int agent_app_ht_alloc(void)
1015 {
1016         int ret = 0;
1017
1018         agent_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1019         if (!agent_apps_ht_by_sock) {
1020                 ret = -1;
1021         }
1022
1023         return ret;
1024 }
1025
1026 /*
1027  * Destroy a agent application by socket.
1028  */
1029 void agent_destroy_app_by_sock(int sock)
1030 {
1031         struct agent_app *app;
1032
1033         assert(sock >= 0);
1034
1035         /*
1036          * Not finding an application is a very important error that should NEVER
1037          * happen. The hash table deletion is ONLY done through this call when the
1038          * main sessiond thread is torn down.
1039          */
1040         rcu_read_lock();
1041         app = agent_find_app_by_sock(sock);
1042         assert(app);
1043
1044         /* RCU read side lock is assumed to be held by this function. */
1045         agent_delete_app(app);
1046
1047         /* The application is freed in a RCU call but the socket is closed here. */
1048         agent_destroy_app(app);
1049         rcu_read_unlock();
1050 }
1051
1052 /*
1053  * Clean-up the agent app hash table and destroy it.
1054  */
1055 void agent_app_ht_clean(void)
1056 {
1057         struct lttng_ht_node_ulong *node;
1058         struct lttng_ht_iter iter;
1059
1060         if (!agent_apps_ht_by_sock) {
1061                 return;
1062         }
1063         rcu_read_lock();
1064         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) {
1065                 struct agent_app *app;
1066
1067                 app = caa_container_of(node, struct agent_app, node);
1068                 agent_destroy_app_by_sock(app->sock->fd);
1069         }
1070         rcu_read_unlock();
1071
1072         lttng_ht_destroy(agent_apps_ht_by_sock);
1073 }
1074
1075 /*
1076  * Update a agent application (given socket) using the given agent.
1077  *
1078  * Note that this function is most likely to be used with a tracing session
1079  * thus the caller should make sure to hold the appropriate lock(s).
1080  */
1081 void agent_update(struct agent *agt, int sock)
1082 {
1083         int ret;
1084         struct agent_app *app;
1085         struct agent_event *event;
1086         struct lttng_ht_iter iter;
1087
1088         assert(agt);
1089         assert(sock >= 0);
1090
1091         DBG("Agent updating app socket %d", sock);
1092
1093         rcu_read_lock();
1094         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
1095                 /* Skip event if disabled. */
1096                 if (!event->enabled) {
1097                         continue;
1098                 }
1099
1100                 app = agent_find_app_by_sock(sock);
1101                 /*
1102                  * We are in the registration path thus if the application is gone,
1103                  * there is a serious code flow error.
1104                  */
1105                 assert(app);
1106
1107                 ret = enable_event(app, event);
1108                 if (ret != LTTNG_OK) {
1109                         DBG2("Agent update unable to enable event %s on app pid: %d sock %d",
1110                                         event->name, app->pid, app->sock->fd);
1111                         /* Let's try the others here and don't assume the app is dead. */
1112                         continue;
1113                 }
1114         }
1115         rcu_read_unlock();
1116 }