src/plugins/ctf/lttng-live/lttng-live.c

   1 /*
   2  * lttng-live.c
   3  *
   4  * Babeltrace CTF LTTng-live Client Component
   5  *
   6  * Copyright 2019 Francis Deslauriers <francis.deslauriers@efficios.com>
   7  * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8  * Copyright 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a copy
  13  * of this software and associated documentation files (the "Software"), to deal
  14  * in the Software without restriction, including without limitation the rights
  15  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  16  * copies of the Software, and to permit persons to whom the Software is
  17  * furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included in
  20  * all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  27  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  28  * SOFTWARE.
  29  */
  30
  31 #define BT_COMP_LOG_SELF_COMP self_comp
  32 #define BT_LOG_OUTPUT_LEVEL log_level
  33 #define BT_LOG_TAG "PLUGIN/SRC.CTF.LTTNG-LIVE"
  34 #include "logging/comp-logging.h"
  35
  36 #include <glib.h>
  37 #include <inttypes.h>
  38 #include <stdbool.h>
  39 #include <unistd.h>
  40
  41 #include "common/assert.h"
  42 #include <babeltrace2/babeltrace.h>
  43 #include "compat/compiler.h"
  44 #include <babeltrace2/types.h>
  45
  46 #include "plugins/common/muxing/muxing.h"
  47 #include "plugins/common/param-validation/param-validation.h"
  48
  49 #include "data-stream.h"
  50 #include "metadata.h"
  51 #include "lttng-live.h"
  52
  53 #define MAX_QUERY_SIZE                      (256*1024)
  54 #define URL_PARAM                           "url"
  55 #define INPUTS_PARAM                        "inputs"
  56 #define SESS_NOT_FOUND_ACTION_PARAM         "session-not-found-action"
  57 #define SESS_NOT_FOUND_ACTION_CONTINUE_STR  "continue"
  58 #define SESS_NOT_FOUND_ACTION_FAIL_STR      "fail"
  59 #define SESS_NOT_FOUND_ACTION_END_STR       "end"
  60
  61 #define print_dbg(fmt, ...)     BT_COMP_LOGD(fmt, ## __VA_ARGS__)
  62
  63 static
  64 const char *print_live_iterator_status(enum lttng_live_iterator_status status)
  65 {
  66         switch (status) {
  67         case LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
  68                 return "LTTNG_LIVE_ITERATOR_STATUS_CONTINUE";
  69         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
  70                 return "LTTNG_LIVE_ITERATOR_STATUS_AGAIN";
  71         case LTTNG_LIVE_ITERATOR_STATUS_END:
  72                 return "LTTNG_LIVE_ITERATOR_STATUS_END";
  73         case LTTNG_LIVE_ITERATOR_STATUS_OK:
  74                 return "LTTNG_LIVE_ITERATOR_STATUS_OK";
  75         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
  76                 return "LTTNG_LIVE_ITERATOR_STATUS_INVAL";
  77         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
  78                 return "LTTNG_LIVE_ITERATOR_STATUS_ERROR";
  79         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
  80                 return "LTTNG_LIVE_ITERATOR_STATUS_NOMEM";
  81         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
  82                 return "LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED";
  83         default:
  84                 abort();
  85         }
  86 }
  87
  88 static
  89 const char *print_state(struct lttng_live_stream_iterator *s)
  90 {
  91         switch (s->state) {
  92         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
  93                 return "ACTIVE_NO_DATA";
  94         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
  95                 return "QUIESCENT_NO_DATA";
  96         case LTTNG_LIVE_STREAM_QUIESCENT:
  97                 return "QUIESCENT";
  98         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
  99                 return "ACTIVE_DATA";
 100         case LTTNG_LIVE_STREAM_EOF:
 101                 return "EOF";
 102         default:
 103                 return "ERROR";
 104         }
 105 }
 106
 107 #define print_stream_state(live_stream_iter) \
 108         do { \
 109                 BT_COMP_LOGD("stream state %s last_inact_ts %" PRId64  \
 110                         ", curr_inact_ts %" PRId64, \
 111                         print_state(live_stream_iter), \
 112                         live_stream_iter->last_inactivity_ts, \
 113                         live_stream_iter->current_inactivity_ts); \
 114         } while (0);
 115
 116 BT_HIDDEN
 117 bool lttng_live_graph_is_canceled(struct lttng_live_msg_iter *msg_iter)
 118 {
 119         bool ret;
 120
 121         if (!msg_iter) {
 122                 ret = false;
 123                 goto end;
 124         }
 125
 126         ret = bt_self_message_iterator_is_interrupted(
 127                 msg_iter->self_msg_iter);
 128
 129 end:
 130         return ret;
 131 }
 132
 133 static
 134 struct lttng_live_trace *lttng_live_find_trace(struct lttng_live_session *session,
 135                 uint64_t trace_id)
 136 {
 137         uint64_t trace_idx;
 138         struct lttng_live_trace *ret_trace = NULL;
 139
 140         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 141                 struct lttng_live_trace *trace =
 142                         g_ptr_array_index(session->traces, trace_idx);
 143                 if (trace->id == trace_id) {
 144                         ret_trace = trace;
 145                         goto end;
 146                 }
 147         }
 148
 149 end:
 150         return ret_trace;
 151 }
 152
 153 static
 154 void lttng_live_destroy_trace(struct lttng_live_trace *trace)
 155 {
 156         bt_logging_level log_level = trace->log_level;
 157         bt_self_component *self_comp = trace->self_comp;
 158
 159         BT_COMP_LOGD("Destroy lttng_live_trace");
 160
 161         BT_ASSERT(trace->stream_iterators);
 162         g_ptr_array_free(trace->stream_iterators, TRUE);
 163
 164         BT_TRACE_PUT_REF_AND_RESET(trace->trace);
 165         BT_TRACE_CLASS_PUT_REF_AND_RESET(trace->trace_class);
 166
 167         lttng_live_metadata_fini(trace);
 168         g_free(trace);
 169 }
 170
 171 static
 172 struct lttng_live_trace *lttng_live_create_trace(struct lttng_live_session *session,
 173                 uint64_t trace_id)
 174 {
 175         struct lttng_live_trace *trace = NULL;
 176         bt_logging_level log_level = session->log_level;
 177         bt_self_component *self_comp = session->self_comp;
 178
 179         trace = g_new0(struct lttng_live_trace, 1);
 180         if (!trace) {
 181                 goto error;
 182         }
 183         trace->log_level = session->log_level;
 184         trace->self_comp = session->self_comp;
 185         trace->session = session;
 186         trace->id = trace_id;
 187         trace->trace_class = NULL;
 188         trace->trace = NULL;
 189         trace->stream_iterators = g_ptr_array_new_with_free_func(
 190                 (GDestroyNotify) lttng_live_stream_iterator_destroy);
 191         BT_ASSERT(trace->stream_iterators);
 192         trace->new_metadata_needed = true;
 193         g_ptr_array_add(session->traces, trace);
 194
 195         BT_COMP_LOGI("Create trace");
 196         goto end;
 197 error:
 198         g_free(trace);
 199         trace = NULL;
 200 end:
 201         return trace;
 202 }
 203
 204 BT_HIDDEN
 205 struct lttng_live_trace *lttng_live_borrow_trace(
 206                 struct lttng_live_session *session, uint64_t trace_id)
 207 {
 208         struct lttng_live_trace *trace;
 209
 210         trace = lttng_live_find_trace(session, trace_id);
 211         if (trace) {
 212                 goto end;
 213         }
 214
 215         /* The session is the owner of the newly created trace. */
 216         trace = lttng_live_create_trace(session, trace_id);
 217
 218 end:
 219         return trace;
 220 }
 221
 222 BT_HIDDEN
 223 int lttng_live_add_session(struct lttng_live_msg_iter *lttng_live_msg_iter,
 224                 uint64_t session_id, const char *hostname,
 225                 const char *session_name)
 226 {
 227         int ret = 0;
 228         struct lttng_live_session *session;
 229         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 230         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 231
 232         session = g_new0(struct lttng_live_session, 1);
 233         if (!session) {
 234                 goto error;
 235         }
 236
 237         session->log_level = lttng_live_msg_iter->log_level;
 238         session->self_comp = lttng_live_msg_iter->self_comp;
 239         session->id = session_id;
 240         session->traces = g_ptr_array_new_with_free_func(
 241                 (GDestroyNotify) lttng_live_destroy_trace);
 242         BT_ASSERT(session->traces);
 243         session->lttng_live_msg_iter = lttng_live_msg_iter;
 244         session->new_streams_needed = true;
 245         session->hostname = g_string_new(hostname);
 246         BT_ASSERT(session->hostname);
 247
 248         session->session_name = g_string_new(session_name);
 249         BT_ASSERT(session->session_name);
 250
 251         BT_COMP_LOGI("Reading from session: %" PRIu64 " hostname: %s session_name: %s",
 252                 session->id, hostname, session_name);
 253         g_ptr_array_add(lttng_live_msg_iter->sessions, session);
 254         goto end;
 255 error:
 256         BT_COMP_LOGE("Error adding session");
 257         g_free(session);
 258         ret = -1;
 259 end:
 260         return ret;
 261 }
 262
 263 static
 264 void lttng_live_destroy_session(struct lttng_live_session *session)
 265 {
 266         bt_logging_level log_level;
 267         bt_self_component *self_comp;
 268
 269         if (!session) {
 270                 goto end;
 271         }
 272
 273         log_level = session->log_level;
 274         self_comp = session->self_comp;
 275         BT_COMP_LOGD("Destroy lttng live session");
 276         if (session->id != -1ULL) {
 277                 if (lttng_live_detach_session(session)) {
 278                         if (!lttng_live_graph_is_canceled(
 279                                         session->lttng_live_msg_iter)) {
 280                                 /* Old relayd cannot detach sessions. */
 281                                 BT_COMP_LOGD("Unable to detach lttng live session %" PRIu64,
 282                                         session->id);
 283                         }
 284                 }
 285                 session->id = -1ULL;
 286         }
 287
 288         if (session->traces) {
 289                 g_ptr_array_free(session->traces, TRUE);
 290         }
 291
 292         if (session->hostname) {
 293                 g_string_free(session->hostname, TRUE);
 294         }
 295         if (session->session_name) {
 296                 g_string_free(session->session_name, TRUE);
 297         }
 298         g_free(session);
 299
 300 end:
 301         return;
 302 }
 303
 304 static
 305 void lttng_live_msg_iter_destroy(struct lttng_live_msg_iter *lttng_live_msg_iter)
 306 {
 307         if (!lttng_live_msg_iter) {
 308                 goto end;
 309         }
 310
 311         if (lttng_live_msg_iter->sessions) {
 312                 g_ptr_array_free(lttng_live_msg_iter->sessions, TRUE);
 313         }
 314
 315         BT_OBJECT_PUT_REF_AND_RESET(lttng_live_msg_iter->viewer_connection);
 316         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp);
 317         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp->has_msg_iter);
 318
 319         /* All stream iterators must be destroyed at this point. */
 320         BT_ASSERT(lttng_live_msg_iter->active_stream_iter == 0);
 321         lttng_live_msg_iter->lttng_live_comp->has_msg_iter = false;
 322
 323         g_free(lttng_live_msg_iter);
 324
 325 end:
 326         return;
 327 }
 328
 329 BT_HIDDEN
 330 void lttng_live_msg_iter_finalize(bt_self_message_iterator *self_msg_iter)
 331 {
 332         struct lttng_live_msg_iter *lttng_live_msg_iter;
 333
 334         BT_ASSERT(self_msg_iter);
 335
 336         lttng_live_msg_iter = bt_self_message_iterator_get_data(self_msg_iter);
 337         BT_ASSERT(lttng_live_msg_iter);
 338         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
 339 }
 340
 341 static
 342 enum lttng_live_iterator_status lttng_live_iterator_next_check_stream_state(
 343                 struct lttng_live_stream_iterator *lttng_live_stream)
 344 {
 345         bt_logging_level log_level = lttng_live_stream->log_level;
 346         bt_self_component *self_comp = lttng_live_stream->self_comp;
 347
 348         switch (lttng_live_stream->state) {
 349         case LTTNG_LIVE_STREAM_QUIESCENT:
 350         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
 351                 break;
 352         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
 353                 /* Invalid state. */
 354                 BT_COMP_LOGF("Unexpected stream state \"ACTIVE_NO_DATA\"");
 355                 abort();
 356         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
 357                 /* Invalid state. */
 358                 BT_COMP_LOGF("Unexpected stream state \"QUIESCENT_NO_DATA\"");
 359                 abort();
 360         case LTTNG_LIVE_STREAM_EOF:
 361                 break;
 362         }
 363         return LTTNG_LIVE_ITERATOR_STATUS_OK;
 364 }
 365
 366 /*
 367  * For active no data stream, fetch next data. It can be either:
 368  * - quiescent: need to put it in the prio heap at quiescent end
 369  *   timestamp,
 370  * - have data: need to wire up first event into the prio heap,
 371  * - have no data on this stream at this point: need to retry (AGAIN) or
 372  *   return EOF.
 373  */
 374 static
 375 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_no_data_stream(
 376                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 377                 struct lttng_live_stream_iterator *lttng_live_stream)
 378 {
 379         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 380         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 381         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 382         enum lttng_live_stream_state orig_state = lttng_live_stream->state;
 383         struct packet_index index;
 384
 385         if (lttng_live_stream->trace->new_metadata_needed) {
 386                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 387                 goto end;
 388         }
 389         if (lttng_live_stream->trace->session->new_streams_needed) {
 390                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 391                 goto end;
 392         }
 393         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_NO_DATA &&
 394                         lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA) {
 395                 goto end;
 396         }
 397         ret = lttng_live_get_next_index(lttng_live_msg_iter, lttng_live_stream,
 398                 &index);
 399         if (ret != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 400                 goto end;
 401         }
 402         BT_ASSERT_DBG(lttng_live_stream->state != LTTNG_LIVE_STREAM_EOF);
 403         if (lttng_live_stream->state == LTTNG_LIVE_STREAM_QUIESCENT) {
 404                 uint64_t last_inact_ts = lttng_live_stream->last_inactivity_ts,
 405                          curr_inact_ts = lttng_live_stream->current_inactivity_ts;
 406
 407                 if (orig_state == LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA &&
 408                                 last_inact_ts == curr_inact_ts) {
 409                         ret = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 410                         print_stream_state(lttng_live_stream);
 411                 } else {
 412                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 413                 }
 414                 goto end;
 415         }
 416         lttng_live_stream->base_offset = index.offset;
 417         lttng_live_stream->offset = index.offset;
 418         lttng_live_stream->len = index.packet_size / CHAR_BIT;
 419 end:
 420         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK) {
 421                 ret = lttng_live_iterator_next_check_stream_state(lttng_live_stream);
 422         }
 423         return ret;
 424 }
 425
 426 /*
 427  * Creation of the message requires the ctf trace class to be created
 428  * beforehand, but the live protocol gives us all streams (including metadata)
 429  * at once. So we split it in three steps: getting streams, getting metadata
 430  * (which creates the ctf trace class), and then creating the per-stream
 431  * messages.
 432  */
 433 static
 434 enum lttng_live_iterator_status lttng_live_get_session(
 435                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 436                 struct lttng_live_session *session)
 437 {
 438         enum lttng_live_iterator_status status;
 439         uint64_t trace_idx;
 440
 441         if (!session->attached) {
 442                 enum lttng_live_attach_session_status attach_status =
 443                         lttng_live_attach_session(session);
 444                 if (attach_status != LTTNG_LIVE_ATTACH_SESSION_STATUS_OK) {
 445                         if (lttng_live_graph_is_canceled(lttng_live_msg_iter)) {
 446                                 status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 447                         } else {
 448                                 status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 449                         }
 450                         goto end;
 451                 }
 452         }
 453
 454         status = lttng_live_get_new_streams(session);
 455         if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 456                         status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 457                 goto end;
 458         }
 459         trace_idx = 0;
 460         while (trace_idx < session->traces->len) {
 461                 struct lttng_live_trace *trace =
 462                         g_ptr_array_index(session->traces, trace_idx);
 463
 464                 status = lttng_live_metadata_update(trace);
 465                 switch (status) {
 466                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 467                         trace_idx++;
 468                         break;
 469                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 470                         /*
 471                          * The trace has ended. Remove it of the array an
 472                          * continue the iteration.
 473                          * We can remove the trace safely when using the
 474                          * g_ptr_array_remove_index_fast because it replaces
 475                          * the element at trace_idx with the array's last
 476                          * element. trace_idx is not incremented because of
 477                          * that.
 478                          */
 479                         (void) g_ptr_array_remove_index_fast(session->traces,
 480                                 trace_idx);
 481                         break;
 482                 default:
 483                         goto end;
 484                 }
 485         }
 486         status = lttng_live_lazy_msg_init(session);
 487
 488 end:
 489         return status;
 490 }
 491
 492 BT_HIDDEN
 493 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 494 {
 495         uint64_t session_idx;
 496
 497         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 498                         session_idx++) {
 499                 struct lttng_live_session *session =
 500                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 501                 session->new_streams_needed = true;
 502         }
 503 }
 504
 505 static
 506 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 507 {
 508         uint64_t session_idx, trace_idx;
 509
 510         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 511                         session_idx++) {
 512                 struct lttng_live_session *session =
 513                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 514                 session->new_streams_needed = true;
 515                 for (trace_idx = 0; trace_idx < session->traces->len;
 516                                 trace_idx++) {
 517                         struct lttng_live_trace *trace =
 518                                 g_ptr_array_index(session->traces, trace_idx);
 519                         trace->new_metadata_needed = true;
 520                 }
 521         }
 522 }
 523
 524 static
 525 enum lttng_live_iterator_status
 526 lttng_live_iterator_handle_new_streams_and_metadata(
 527                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 528 {
 529         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 530         uint64_t session_idx = 0, nr_sessions_opened = 0;
 531         struct lttng_live_session *session;
 532         enum session_not_found_action sess_not_found_act =
 533                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 534
 535         /*
 536          * In a remotely distant future, we could add a "new
 537          * session" flag to the protocol, which would tell us that we
 538          * need to query for new sessions even though we have sessions
 539          * currently ongoing.
 540          */
 541         if (lttng_live_msg_iter->sessions->len == 0) {
 542                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 543                         ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 544                         goto end;
 545                 } else {
 546                         /*
 547                          * Retry to create a viewer session for the requested
 548                          * session name.
 549                          */
 550                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
 551                                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 552                                 goto end;
 553                         }
 554                 }
 555         }
 556
 557         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 558                         session_idx++) {
 559                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 560                                 session_idx);
 561                 ret = lttng_live_get_session(lttng_live_msg_iter, session);
 562                 switch (ret) {
 563                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 564                         break;
 565                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 566                         ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 567                         break;
 568                 default:
 569                         goto end;
 570                 }
 571                 if (!session->closed) {
 572                         nr_sessions_opened++;
 573                 }
 574         }
 575 end:
 576         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK &&
 577                         sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 578                         nr_sessions_opened == 0) {
 579                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 580         }
 581         return ret;
 582 }
 583
 584 static
 585 enum lttng_live_iterator_status emit_inactivity_message(
 586                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 587                 struct lttng_live_stream_iterator *stream_iter,
 588                 bt_message **message, uint64_t timestamp)
 589 {
 590         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 591         bt_message *msg = NULL;
 592
 593         BT_ASSERT(stream_iter->trace->clock_class);
 594
 595         msg = bt_message_message_iterator_inactivity_create(
 596                 lttng_live_msg_iter->self_msg_iter,
 597                 stream_iter->trace->clock_class, timestamp);
 598         if (!msg) {
 599                 goto error;
 600         }
 601
 602         *message = msg;
 603 end:
 604         return ret;
 605
 606 error:
 607         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 608         bt_message_put_ref(msg);
 609         goto end;
 610 }
 611
 612 static
 613 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 614                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 615                 struct lttng_live_stream_iterator *lttng_live_stream,
 616                 bt_message **message)
 617 {
 618         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 619
 620         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 621                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 622         }
 623
 624         if (lttng_live_stream->current_inactivity_ts ==
 625                         lttng_live_stream->last_inactivity_ts) {
 626                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 627                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 628                 goto end;
 629         }
 630
 631         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 632                 message, lttng_live_stream->current_inactivity_ts);
 633
 634         lttng_live_stream->last_inactivity_ts =
 635                 lttng_live_stream->current_inactivity_ts;
 636 end:
 637         return ret;
 638 }
 639
 640 static
 641 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 642                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 643                 const bt_message *msg, int64_t last_msg_ts_ns,
 644                 int64_t *ts_ns)
 645 {
 646         const bt_clock_class *clock_class = NULL;
 647         const bt_clock_snapshot *clock_snapshot = NULL;
 648         int ret = 0;
 649         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 650         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 651
 652         BT_ASSERT_DBG(msg);
 653         BT_ASSERT_DBG(ts_ns);
 654
 655         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 656                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 657                 last_msg_ts_ns);
 658
 659         switch (bt_message_get_type(msg)) {
 660         case BT_MESSAGE_TYPE_EVENT:
 661                 clock_class = bt_message_event_borrow_stream_class_default_clock_class_const(
 662                                 msg);
 663                 BT_ASSERT_DBG(clock_class);
 664
 665                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 666                         msg);
 667                 break;
 668         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 669                 clock_class = bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 670                         msg);
 671                 BT_ASSERT(clock_class);
 672
 673                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 674                         msg);
 675                 break;
 676         case BT_MESSAGE_TYPE_PACKET_END:
 677                 clock_class = bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 678                         msg);
 679                 BT_ASSERT(clock_class);
 680
 681                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 682                         msg);
 683                 break;
 684         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 685                 clock_class = bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 686                         msg);
 687                 BT_ASSERT(clock_class);
 688
 689                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 690                         msg);
 691                 break;
 692         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 693                 clock_class = bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 694                         msg);
 695                 BT_ASSERT(clock_class);
 696
 697                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 698                         msg);
 699                 break;
 700         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 701                 clock_snapshot = bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 702                         msg);
 703                 break;
 704         default:
 705                 /* All the other messages have a higher priority */
 706                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 707                 *ts_ns = last_msg_ts_ns;
 708                 goto end;
 709         }
 710
 711         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 712         BT_ASSERT_DBG(clock_class);
 713
 714         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 715         if (ret) {
 716                 BT_COMP_LOGE("Cannot get nanoseconds from Epoch of clock snapshot: "
 717                         "clock-snapshot-addr=%p", clock_snapshot);
 718                 goto error;
 719         }
 720
 721         goto end;
 722
 723 error:
 724         ret = -1;
 725
 726 end:
 727         if (ret == 0) {
 728                 BT_COMP_LOGD("Found message's timestamp: "
 729                         "iter-data-addr=%p, msg-addr=%p, "
 730                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 731                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 732         }
 733
 734         return ret;
 735 }
 736
 737 static
 738 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 739                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 740                 struct lttng_live_stream_iterator *lttng_live_stream,
 741                 bt_message **message)
 742 {
 743         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 744         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 745         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 746         enum bt_msg_iter_status status;
 747         uint64_t session_idx, trace_idx;
 748
 749         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 750                         session_idx++) {
 751                 struct lttng_live_session *session =
 752                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 753
 754                 if (session->new_streams_needed) {
 755                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 756                         goto end;
 757                 }
 758                 for (trace_idx = 0; trace_idx < session->traces->len;
 759                                 trace_idx++) {
 760                         struct lttng_live_trace *trace =
 761                                 g_ptr_array_index(session->traces, trace_idx);
 762                         if (trace->new_metadata_needed) {
 763                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 764                                 goto end;
 765                         }
 766                 }
 767         }
 768
 769         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 770                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 771                 goto end;
 772         }
 773
 774         status = bt_msg_iter_get_next_message(lttng_live_stream->msg_iter,
 775                 lttng_live_msg_iter->self_msg_iter, message);
 776         switch (status) {
 777         case BT_MSG_ITER_STATUS_EOF:
 778                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 779                 break;
 780         case BT_MSG_ITER_STATUS_OK:
 781                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 782                 break;
 783         case BT_MSG_ITER_STATUS_AGAIN:
 784                 /*
 785                  * Continue immediately (end of packet). The next
 786                  * get_index may return AGAIN to delay the following
 787                  * attempt.
 788                  */
 789                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 790                 break;
 791         case BT_MSG_ITER_STATUS_INVAL:
 792                 /* No argument provided by the user, so don't return INVAL. */
 793         case BT_MSG_ITER_STATUS_ERROR:
 794         default:
 795                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 796                 BT_COMP_LOGW("CTF msg iterator return an error or failed msg_iter=%p",
 797                         lttng_live_stream->msg_iter);
 798                 break;
 799         }
 800
 801 end:
 802         return ret;
 803 }
 804
 805 static
 806 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 807                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 808                 struct lttng_live_stream_iterator *stream_iter,
 809                 bt_message **curr_msg)
 810 {
 811         enum lttng_live_iterator_status live_status =
 812                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 813         /*
 814          * The viewer has hung up on us so we are closing the stream. The
 815          * `bt_msg_iter` should simply realize that it needs to close the
 816          * stream properly by emitting the necessary stream end message.
 817          */
 818         enum bt_msg_iter_status status = bt_msg_iter_get_next_message(
 819                 stream_iter->msg_iter, lttng_live_msg_iter->self_msg_iter,
 820                 curr_msg);
 821
 822         if (status == BT_MSG_ITER_STATUS_ERROR) {
 823                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 824                 goto end;
 825         }
 826
 827         BT_ASSERT(status == BT_MSG_ITER_STATUS_OK);
 828
 829 end:
 830         return live_status;
 831 }
 832
 833 /*
 834  * helper function:
 835  *            handle_no_data_streams()
 836  *              retry:
 837  *                - for each ACTIVE_NO_DATA stream:
 838  *                  - query relayd for stream data, or quiescence info.
 839  *                    - if need metadata, get metadata, goto retry.
 840  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 841  *                  - if quiescent, move to QUIESCENT streams
 842  *                  - if fetched data, move to ACTIVE_DATA streams
 843  *                (at this point each stream either has data, or is quiescent)
 844  *
 845  *
 846  * iterator_next:
 847  *            handle_new_streams_and_metadata()
 848  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 849  *                  - query relayd for metadata
 850  *
 851  *            call handle_active_no_data_streams()
 852  *
 853  *            handle_quiescent_streams()
 854  *                - if at least one stream is ACTIVE_DATA:
 855  *                  - peek stream event with lowest timestamp -> next_ts
 856  *                  - for each quiescent stream
 857  *                    - if next_ts >= quiescent end
 858  *                      - set state to ACTIVE_NO_DATA
 859  *                - else
 860  *                  - for each quiescent stream
 861  *                      - set state to ACTIVE_NO_DATA
 862  *
 863  *            call handle_active_no_data_streams()
 864  *
 865  *            handle_active_data_streams()
 866  *                - if at least one stream is ACTIVE_DATA:
 867  *                    - get stream event with lowest timestamp from heap
 868  *                    - make that stream event the current message.
 869  *                    - move this stream heap position to its next event
 870  *                      - if we need to fetch data from relayd, move
 871  *                        stream to ACTIVE_NO_DATA.
 872  *                    - return OK
 873  *                - return AGAIN
 874  *
 875  * end criterion: ctrl-c on client. If relayd exits or the session
 876  * closes on the relay daemon side, we keep on waiting for streams.
 877  * Eventually handle --end timestamp (also an end criterion).
 878  *
 879  * When disconnected from relayd: try to re-connect endlessly.
 880  */
 881 static
 882 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 883                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 884                 struct lttng_live_stream_iterator *stream_iter,
 885                 bt_message **curr_msg)
 886 {
 887         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 888         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 889         enum lttng_live_iterator_status live_status;
 890
 891         if (stream_iter->has_stream_hung_up) {
 892                 /*
 893                  * The stream has hung up and the stream was properly closed
 894                  * during the last call to the current function. Return _END
 895                  * status now so that this stream iterator is removed for the
 896                  * stream iterator list.
 897                  */
 898                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 899                 goto end;
 900         }
 901
 902 retry:
 903         print_stream_state(stream_iter);
 904         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 905                 lttng_live_msg_iter);
 906         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 907                 goto end;
 908         }
 909         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 910                 lttng_live_msg_iter, stream_iter);
 911
 912         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 913                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 914                         /*
 915                          * We overwrite `live_status` since `curr_msg` is
 916                          * likely set to a valid message in this function.
 917                          */
 918                         live_status = lttng_live_iterator_close_stream(
 919                                 lttng_live_msg_iter, stream_iter, curr_msg);
 920                 }
 921                 goto end;
 922         }
 923         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 924                 lttng_live_msg_iter, stream_iter, curr_msg);
 925         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 926                 BT_ASSERT(!*curr_msg);
 927                 goto end;
 928         }
 929         if (*curr_msg) {
 930                 goto end;
 931         }
 932         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 933                 lttng_live_msg_iter, stream_iter, curr_msg);
 934         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 935                 BT_ASSERT(!*curr_msg);
 936         }
 937
 938 end:
 939         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 940                 goto retry;
 941         }
 942
 943         return live_status;
 944 }
 945
 946 static
 947 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 948                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 949                 struct lttng_live_trace *live_trace,
 950                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 951 {
 952         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 953         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 954         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 955         enum lttng_live_iterator_status stream_iter_status;;
 956         int64_t youngest_candidate_msg_ts = INT64_MAX;
 957         uint64_t stream_iter_idx;
 958
 959         BT_ASSERT_DBG(live_trace);
 960         BT_ASSERT_DBG(live_trace->stream_iterators);
 961         /*
 962          * Update the current message of every stream iterators of this trace.
 963          * The current msg of every stream must have a timestamp equal or
 964          * larger than the last message returned by this iterator. We must
 965          * ensure monotonicity.
 966          */
 967         stream_iter_idx = 0;
 968         while (stream_iter_idx < live_trace->stream_iterators->len) {
 969                 bool stream_iter_is_ended = false;
 970                 struct lttng_live_stream_iterator *stream_iter =
 971                         g_ptr_array_index(live_trace->stream_iterators,
 972                                 stream_iter_idx);
 973
 974                 /*
 975                  * Find if there is are now current message for this stream
 976                  * iterator get it.
 977                  */
 978                 while (!stream_iter->current_msg) {
 979                         bt_message *msg = NULL;
 980                         int64_t curr_msg_ts_ns = INT64_MAX;
 981                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
 982                                 lttng_live_msg_iter, stream_iter, &msg);
 983
 984                         BT_COMP_LOGD("live stream iterator returned status :%s",
 985                                 print_live_iterator_status(stream_iter_status));
 986                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 987                                 stream_iter_is_ended = true;
 988                                 break;
 989                         }
 990
 991                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 992                                 goto end;
 993                         }
 994
 995                         BT_ASSERT_DBG(msg);
 996
 997                         /*
 998                          * Get the timestamp in nanoseconds from origin of this
 999                          * messsage.
1000                          */
1001                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
1002                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
1003                                 &curr_msg_ts_ns);
1004
1005                         /*
1006                          * Check if the message of the current live stream
1007                          * iterator occured at the exact same time or after the
1008                          * last message returned by this component's message
1009                          * iterator. If not, we return an error.
1010                          */
1011                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
1012                                 stream_iter->current_msg = msg;
1013                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
1014                         } else {
1015                                 /*
1016                                  * We received a message in the past. To ensure
1017                                  * monotonicity, we can't send it forward.
1018                                  */
1019                                 BT_COMP_LOGE("Message's timestamp is less than "
1020                                         "lttng-live's message iterator's last "
1021                                         "returned timestamp: "
1022                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1023                                         "last-msg-ts=%" PRId64,
1024                                         lttng_live_msg_iter, curr_msg_ts_ns,
1025                                         lttng_live_msg_iter->last_msg_ts_ns);
1026                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1027                                 goto end;
1028                         }
1029                 }
1030
1031                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1032
1033                 if (!stream_iter_is_ended) {
1034                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1035                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1036                                 /*
1037                                  * Update the current best candidate message
1038                                  * for the stream iterator of this live trace
1039                                  * to be forwarded downstream.
1040                                  */
1041                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1042                                 youngest_candidate_stream_iter = stream_iter;
1043                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1044                                 /*
1045                                  * Order the messages in an arbitrary but
1046                                  * deterministic way.
1047                                  */
1048                                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1049                                 int ret = common_muxing_compare_messages(
1050                                         stream_iter->current_msg,
1051                                         youngest_candidate_stream_iter->current_msg);
1052                                 if (ret < 0) {
1053                                         /*
1054                                          * The `youngest_candidate_stream_iter->current_msg`
1055                                          * should go first. Update the next
1056                                          * iterator and the current timestamp.
1057                                          */
1058                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1059                                         youngest_candidate_stream_iter = stream_iter;
1060                                 } else if (ret == 0) {
1061                                         /*
1062                                          * Unable to pick which one should go
1063                                          * first.
1064                                          */
1065                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1066                                                 "stream-iter-addr=%p"
1067                                                 "stream-iter-addr=%p",
1068                                                 stream_iter,
1069                                                 youngest_candidate_stream_iter);
1070                                 }
1071                         }
1072
1073                         stream_iter_idx++;
1074                 } else {
1075                         /*
1076                          * The live stream iterator has ended. That
1077                          * iterator is removed from the array, but
1078                          * there is no need to increment
1079                          * stream_iter_idx as
1080                          * g_ptr_array_remove_index_fast replaces the
1081                          * removed element with the array's last
1082                          * element.
1083                          */
1084                         g_ptr_array_remove_index_fast(
1085                                 live_trace->stream_iterators,
1086                                 stream_iter_idx);
1087                 }
1088         }
1089
1090         if (youngest_candidate_stream_iter) {
1091                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1092                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1093         } else {
1094                 /*
1095                  * The only case where we don't have a candidate for this trace
1096                  * is if we reached the end of all the iterators.
1097                  */
1098                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1099                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1100         }
1101
1102 end:
1103         return stream_iter_status;
1104 }
1105
1106 static
1107 enum lttng_live_iterator_status next_stream_iterator_for_session(
1108                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1109                 struct lttng_live_session *session,
1110                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1111 {
1112         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1113         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1114         enum lttng_live_iterator_status stream_iter_status;
1115         uint64_t trace_idx = 0;
1116         int64_t youngest_candidate_msg_ts = INT64_MAX;
1117         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1118
1119         /*
1120          * Make sure we are attached to the session and look for new streams
1121          * and metadata.
1122          */
1123         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1124         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1125                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1126                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1127                 goto end;
1128         }
1129
1130         BT_ASSERT_DBG(session->traces);
1131
1132         while (trace_idx < session->traces->len) {
1133                 bool trace_is_ended = false;
1134                 struct lttng_live_stream_iterator *stream_iter;
1135                 struct lttng_live_trace *trace =
1136                         g_ptr_array_index(session->traces, trace_idx);
1137
1138                 stream_iter_status = next_stream_iterator_for_trace(
1139                         lttng_live_msg_iter, trace, &stream_iter);
1140                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1141                         /*
1142                          * All the live stream iterators for this trace are
1143                          * ENDed. Remove the trace from this session.
1144                          */
1145                         trace_is_ended = true;
1146                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1147                         goto end;
1148                 }
1149
1150                 if (!trace_is_ended) {
1151                         BT_ASSERT_DBG(stream_iter);
1152
1153                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1154                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1155                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1156                                 youngest_candidate_stream_iter = stream_iter;
1157                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1158                                 /*
1159                                  * Order the messages in an arbitrary but
1160                                  * deterministic way.
1161                                  */
1162                                 int ret = common_muxing_compare_messages(
1163                                         stream_iter->current_msg,
1164                                         youngest_candidate_stream_iter->current_msg);
1165                                 if (ret < 0) {
1166                                         /*
1167                                          * The `youngest_candidate_stream_iter->current_msg`
1168                                          * should go first. Update the next iterator
1169                                          * and the current timestamp.
1170                                          */
1171                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1172                                         youngest_candidate_stream_iter = stream_iter;
1173                                 } else if (ret == 0) {
1174                                         /* Unable to pick which one should go first. */
1175                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1176                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1177                                                 stream_iter, youngest_candidate_stream_iter);
1178                                 }
1179                         }
1180                         trace_idx++;
1181                 } else {
1182                         /*
1183                          * trace_idx is not incremented since
1184                          * g_ptr_array_remove_index_fast replaces the
1185                          * element at trace_idx with the array's last element.
1186                          */
1187                         g_ptr_array_remove_index_fast(session->traces,
1188                                 trace_idx);
1189                 }
1190         }
1191         if (youngest_candidate_stream_iter) {
1192                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1193                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1194         } else {
1195                 /*
1196                  * The only cases where we don't have a candidate for this
1197                  * trace is:
1198                  *  1. if we reached the end of all the iterators of all the
1199                  *  traces of this session,
1200                  *  2. if we never had live stream iterator in the first place.
1201                  *
1202                  * In either cases, we return END.
1203                  */
1204                 BT_ASSERT(session->traces->len == 0);
1205                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1206         }
1207 end:
1208         return stream_iter_status;
1209 }
1210
1211 static inline
1212 void put_messages(bt_message_array_const msgs, uint64_t count)
1213 {
1214         uint64_t i;
1215
1216         for (i = 0; i < count; i++) {
1217                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1218         }
1219 }
1220
1221 BT_HIDDEN
1222 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1223                 bt_self_message_iterator *self_msg_it,
1224                 bt_message_array_const msgs, uint64_t capacity,
1225                 uint64_t *count)
1226 {
1227         bt_component_class_message_iterator_next_method_status status;
1228         struct lttng_live_msg_iter *lttng_live_msg_iter =
1229                 bt_self_message_iterator_get_data(self_msg_it);
1230         struct lttng_live_component *lttng_live =
1231                 lttng_live_msg_iter->lttng_live_comp;
1232         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1233         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1234         enum lttng_live_iterator_status stream_iter_status;
1235         uint64_t session_idx;
1236
1237         *count = 0;
1238
1239         BT_ASSERT_DBG(lttng_live_msg_iter);
1240
1241         /*
1242          * Clear all the invalid message reference that might be left over in
1243          * the output array.
1244          */
1245         memset(msgs, 0, capacity * sizeof(*msgs));
1246
1247         /*
1248          * If no session are exposed on the relay found at the url provided by
1249          * the user, session count will be 0. In this case, we return status
1250          * end to return gracefully.
1251          */
1252         if (lttng_live_msg_iter->sessions->len == 0) {
1253                 if (lttng_live->params.sess_not_found_act !=
1254                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1255                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1256                         goto no_session;
1257                 } else {
1258                         /*
1259                          * The are no more active session for this session
1260                          * name. Retry to create a viewer session for the
1261                          * requested session name.
1262                          */
1263                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1264                                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1265                                 goto no_session;
1266                         }
1267                 }
1268         }
1269
1270         if (lttng_live_msg_iter->active_stream_iter == 0) {
1271                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1272         }
1273
1274         /*
1275          * Here the muxing of message is done.
1276          *
1277          * We need to iterate over all the streams of all the traces of all the
1278          * viewer sessions in order to get the message with the smallest
1279          * timestamp. In this case, a session is a viewer session and there is
1280          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1281          * kernel). Each viewer session can have multiple traces, for example,
1282          * 64bit UST viewer sessions could have multiple per-pid traces.
1283          *
1284          * We iterate over the streams of each traces to update and see what is
1285          * their next message's timestamp. From those timestamps, we select the
1286          * message with the smallest timestamp as the best candidate message
1287          * for that trace and do the same thing across all the sessions.
1288          *
1289          * We then compare the timestamp of best candidate message of all the
1290          * sessions to pick the message with the smallest timestamp and we
1291          * return it.
1292          */
1293         while (*count < capacity) {
1294                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1295                           *candidate_stream_iter = NULL;
1296                 int64_t youngest_msg_ts_ns = INT64_MAX;
1297
1298                 BT_ASSERT_DBG(lttng_live_msg_iter->sessions);
1299                 session_idx = 0;
1300                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1301                         struct lttng_live_session *session =
1302                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1303                                         session_idx);
1304
1305                         /* Find the best candidate message to send downstream. */
1306                         stream_iter_status = next_stream_iterator_for_session(
1307                                 lttng_live_msg_iter, session,
1308                                 &candidate_stream_iter);
1309
1310                         /* If we receive an END status, it means that either:
1311                          * - Those traces never had active streams (UST with no
1312                          *   data produced yet),
1313                          * - All live stream iterators have ENDed.*/
1314                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1315                                 if (session->closed && session->traces->len == 0) {
1316                                         /*
1317                                          * Remove the session from the list.
1318                                          * session_idx is not modified since
1319                                          * g_ptr_array_remove_index_fast
1320                                          * replaces the the removed element with
1321                                          * the array's last element.
1322                                          */
1323                                         g_ptr_array_remove_index_fast(
1324                                                 lttng_live_msg_iter->sessions,
1325                                                 session_idx);
1326                                 } else {
1327                                         session_idx++;
1328                                 }
1329                                 continue;
1330                         }
1331
1332                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1333                                 goto end;
1334                         }
1335
1336                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1337                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1338                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1339                                 youngest_stream_iter = candidate_stream_iter;
1340                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1341                                 /*
1342                                  * The currently selected message to be sent
1343                                  * downstream next has the exact same timestamp
1344                                  * that of the current candidate message. We
1345                                  * must break the tie in a predictable manner.
1346                                  */
1347                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1348                                 /*
1349                                  * Order the messages in an arbitrary but
1350                                  * deterministic way.
1351                                  */
1352                                 int ret = common_muxing_compare_messages(
1353                                         candidate_stream_iter->current_msg,
1354                                         youngest_stream_iter->current_msg);
1355                                 if (ret < 0) {
1356                                         /*
1357                                          * The `candidate_stream_iter->current_msg`
1358                                          * should go first. Update the next
1359                                          * iterator and the current timestamp.
1360                                          */
1361                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1362                                         youngest_stream_iter = candidate_stream_iter;
1363                                 } else if (ret == 0) {
1364                                         /* Unable to pick which one should go first. */
1365                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1366                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1367                                                 youngest_stream_iter, candidate_stream_iter);
1368                                 }
1369                         }
1370
1371                         session_idx++;
1372                 }
1373
1374                 if (!youngest_stream_iter) {
1375                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1376                         goto end;
1377                 }
1378
1379                 BT_ASSERT_DBG(youngest_stream_iter->current_msg);
1380                 /* Ensure monotonicity. */
1381                 BT_ASSERT_DBG(lttng_live_msg_iter->last_msg_ts_ns <=
1382                         youngest_stream_iter->current_msg_ts_ns);
1383
1384                 /*
1385                  * Insert the next message to the message batch. This will set
1386                  * stream iterator current messsage to NULL so that next time
1387                  * we fetch the next message of that stream iterator
1388                  */
1389                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1390                 (*count)++;
1391
1392                 /* Update the last timestamp in nanoseconds sent downstream. */
1393                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1394                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1395
1396                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1397         }
1398 end:
1399         switch (stream_iter_status) {
1400         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1401         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1402                 if (*count > 0) {
1403                         /*
1404                          * We received a again status but we have some messages
1405                          * to send downstream. We send them and return OK for
1406                          * now. On the next call we return again if there are
1407                          * still no new message to send.
1408                          */
1409                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1410                 } else {
1411                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1412                 }
1413                 break;
1414         case LTTNG_LIVE_ITERATOR_STATUS_END:
1415                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1416                 break;
1417         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1418                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1419                 break;
1420         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1421         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1422         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1423                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1424                 /* Put all existing messages on error. */
1425                 put_messages(msgs, *count);
1426                 break;
1427         default:
1428                 abort();
1429         }
1430
1431 no_session:
1432         return status;
1433 }
1434
1435 BT_HIDDEN
1436 bt_component_class_message_iterator_initialize_method_status lttng_live_msg_iter_init(
1437                 bt_self_message_iterator *self_msg_it,
1438                 bt_self_message_iterator_configuration *config,
1439                 bt_self_component_source *self_comp_src,
1440                 bt_self_component_port_output *self_port)
1441 {
1442         bt_component_class_message_iterator_initialize_method_status ret =
1443                 BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_OK;
1444         bt_self_component *self_comp =
1445                 bt_self_component_source_as_self_component(self_comp_src);
1446         struct lttng_live_component *lttng_live;
1447         struct lttng_live_msg_iter *lttng_live_msg_iter;
1448         bt_logging_level log_level;
1449
1450         BT_ASSERT(self_msg_it);
1451
1452         lttng_live = bt_self_component_get_data(self_comp);
1453         log_level = lttng_live->log_level;
1454         self_comp = lttng_live->self_comp;
1455
1456         /* There can be only one downstream iterator at the same time. */
1457         BT_ASSERT(!lttng_live->has_msg_iter);
1458         lttng_live->has_msg_iter = true;
1459
1460         lttng_live_msg_iter = g_new0(struct lttng_live_msg_iter, 1);
1461         if (!lttng_live_msg_iter) {
1462                 ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1463                 goto end;
1464         }
1465
1466         lttng_live_msg_iter->log_level = lttng_live->log_level;
1467         lttng_live_msg_iter->self_comp = lttng_live->self_comp;
1468         lttng_live_msg_iter->lttng_live_comp = lttng_live;
1469         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1470
1471         lttng_live_msg_iter->active_stream_iter = 0;
1472         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1473         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1474                 (GDestroyNotify) lttng_live_destroy_session);
1475         BT_ASSERT(lttng_live_msg_iter->sessions);
1476
1477         lttng_live_msg_iter->viewer_connection =
1478                 live_viewer_connection_create(lttng_live->params.url->str, false,
1479                         lttng_live_msg_iter, log_level);
1480         if (!lttng_live_msg_iter->viewer_connection) {
1481                 goto error;
1482         }
1483
1484         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1485                 goto error;
1486         }
1487         if (lttng_live_msg_iter->sessions->len == 0) {
1488                 switch (lttng_live->params.sess_not_found_act) {
1489                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1490                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1491                                 "session. Keep trying to connect because of "
1492                                 "%s=\"%s\" component parameter: url=\"%s\"",
1493                                 SESS_NOT_FOUND_ACTION_PARAM,
1494                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1495                                 lttng_live->params.url->str);
1496                         break;
1497                 case SESSION_NOT_FOUND_ACTION_FAIL:
1498                         BT_COMP_LOGE("Unable to connect to the requested live viewer "
1499                                 "session. Fail the message iterator"
1500                                 "initialization because of %s=\"%s\" "
1501                                 "component parameter: url =\"%s\"",
1502                                 SESS_NOT_FOUND_ACTION_PARAM,
1503                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1504                                 lttng_live->params.url->str);
1505                         goto error;
1506                 case SESSION_NOT_FOUND_ACTION_END:
1507                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1508                                 "session. End gracefully at the first _next() "
1509                                 "call because of %s=\"%s\" component parameter: "
1510                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1511                                 SESS_NOT_FOUND_ACTION_END_STR,
1512                                 lttng_live->params.url->str);
1513                         break;
1514                 default:
1515                         abort();
1516                 }
1517         }
1518
1519         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1520
1521         goto end;
1522 error:
1523         ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1524         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1525 end:
1526         return ret;
1527 }
1528
1529 static struct bt_param_validation_map_value_entry_descr list_sessions_params[] = {
1530         { URL_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { .type = BT_VALUE_TYPE_STRING } },
1531         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1532 };
1533
1534 static
1535 bt_component_class_query_method_status lttng_live_query_list_sessions(
1536                 const bt_value *params, const bt_value **result,
1537                 bt_self_component_class *self_comp_class,
1538                 bt_logging_level log_level)
1539 {
1540         bt_component_class_query_method_status status;
1541         const bt_value *url_value = NULL;
1542         const char *url;
1543         struct live_viewer_connection *viewer_connection = NULL;
1544         enum bt_param_validation_status validation_status;
1545         gchar *validate_error = NULL;
1546
1547         validation_status = bt_param_validation_validate(params,
1548                 list_sessions_params, &validate_error);
1549         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1550                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1551                 goto error;
1552         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1553                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1554                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class, "%s", validate_error);
1555                 goto error;
1556         }
1557
1558         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1559         url = bt_value_string_get(url_value);
1560
1561         viewer_connection = live_viewer_connection_create(url, true, NULL,
1562                 log_level);
1563         if (!viewer_connection) {
1564                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1565                 goto error;
1566         }
1567
1568         status = live_viewer_connection_list_sessions(viewer_connection,
1569                 result);
1570         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1571                 goto error;
1572         }
1573
1574         goto end;
1575
1576 error:
1577         BT_VALUE_PUT_REF_AND_RESET(*result);
1578
1579         if (status >= 0) {
1580                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1581         }
1582
1583 end:
1584         if (viewer_connection) {
1585                 live_viewer_connection_destroy(viewer_connection);
1586         }
1587
1588         g_free(validate_error);
1589
1590         return status;
1591 }
1592
1593 static
1594 bt_component_class_query_method_status lttng_live_query_support_info(
1595                 const bt_value *params, const bt_value **result,
1596                 bt_logging_level log_level)
1597 {
1598         bt_component_class_query_method_status status =
1599                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1600         const bt_value *input_type_value;
1601         const bt_value *input_value;
1602         double weight = 0;
1603         struct bt_common_lttng_live_url_parts parts = { 0 };
1604
1605         /* Used by the logging macros */
1606         __attribute__((unused)) bt_self_component *self_comp = NULL;
1607
1608         *result = NULL;
1609         input_type_value = bt_value_map_borrow_entry_value_const(params,
1610                 "type");
1611         if (!input_type_value) {
1612                 BT_COMP_LOGE("Missing expected `type` parameter.");
1613                 goto error;
1614         }
1615
1616         if (!bt_value_is_string(input_type_value)) {
1617                 BT_COMP_LOGE("`type` parameter is not a string value.");
1618                 goto error;
1619         }
1620
1621         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1622                 /* We don't handle file system paths */
1623                 goto create_result;
1624         }
1625
1626         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1627         if (!input_value) {
1628                 BT_COMP_LOGE("Missing expected `input` parameter.");
1629                 goto error;
1630         }
1631
1632         if (!bt_value_is_string(input_value)) {
1633                 BT_COMP_LOGE("`input` parameter is not a string value.");
1634                 goto error;
1635         }
1636
1637         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1638                 NULL, 0);
1639         if (parts.session_name) {
1640                 /*
1641                  * Looks pretty much like an LTTng live URL: we got the
1642                  * session name part, which forms a complete URL.
1643                  */
1644                 weight = .75;
1645         }
1646
1647 create_result:
1648         *result = bt_value_real_create_init(weight);
1649         if (!*result) {
1650                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1651                 goto error;
1652         }
1653
1654         goto end;
1655
1656 error:
1657         if (status >= 0) {
1658                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1659         }
1660
1661         BT_ASSERT(!*result);
1662
1663 end:
1664         bt_common_destroy_lttng_live_url_parts(&parts);
1665         return status;
1666 }
1667
1668 BT_HIDDEN
1669 bt_component_class_query_method_status lttng_live_query(
1670                 bt_self_component_class_source *comp_class,
1671                 bt_private_query_executor *priv_query_exec,
1672                 const char *object, const bt_value *params,
1673                 __attribute__((unused)) void *method_data,
1674                 const bt_value **result)
1675 {
1676         bt_component_class_query_method_status status =
1677                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1678         bt_self_component *self_comp = NULL;
1679         bt_self_component_class *self_comp_class =
1680                 bt_self_component_class_source_as_self_component_class(comp_class);
1681         bt_logging_level log_level = bt_query_executor_get_logging_level(
1682                 bt_private_query_executor_as_query_executor_const(
1683                         priv_query_exec));
1684
1685         if (strcmp(object, "sessions") == 0) {
1686                 status = lttng_live_query_list_sessions(params, result,
1687                         self_comp_class, log_level);
1688         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1689                 status = lttng_live_query_support_info(params, result,
1690                         log_level);
1691         } else {
1692                 BT_COMP_LOGI("Unknown query object `%s`", object);
1693                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1694                 goto end;
1695         }
1696
1697 end:
1698         return status;
1699 }
1700
1701 static
1702 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1703 {
1704         if (!lttng_live) {
1705                 return;
1706         }
1707         if (lttng_live->params.url) {
1708                 g_string_free(lttng_live->params.url, TRUE);
1709         }
1710         g_free(lttng_live);
1711 }
1712
1713 BT_HIDDEN
1714 void lttng_live_component_finalize(bt_self_component_source *component)
1715 {
1716         void *data = bt_self_component_get_data(
1717                 bt_self_component_source_as_self_component(component));
1718
1719         if (!data) {
1720                 return;
1721         }
1722         lttng_live_component_destroy_data(data);
1723 }
1724
1725 static
1726 enum session_not_found_action parse_session_not_found_action_param(
1727         const bt_value *no_session_param)
1728 {
1729         enum session_not_found_action action;
1730         const char *no_session_act_str = bt_value_string_get(no_session_param);
1731
1732         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1733                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1734         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1735                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1736         } else {
1737                 BT_ASSERT(strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0);
1738                 action = SESSION_NOT_FOUND_ACTION_END;
1739         }
1740
1741         return action;
1742 }
1743
1744 static struct bt_param_validation_value_descr inputs_elem_descr = {
1745         .type = BT_VALUE_TYPE_STRING,
1746 };
1747
1748 static const char *sess_not_found_action_choices[] = {
1749         SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1750         SESS_NOT_FOUND_ACTION_FAIL_STR,
1751         SESS_NOT_FOUND_ACTION_END_STR,
1752 };
1753
1754 static struct bt_param_validation_map_value_entry_descr params_descr[] = {
1755         { INPUTS_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { BT_VALUE_TYPE_ARRAY, .array = {
1756                 .min_length = 1,
1757                 .max_length = 1,
1758                 .element_type = &inputs_elem_descr,
1759         } } },
1760         { SESS_NOT_FOUND_ACTION_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL, { BT_VALUE_TYPE_STRING, .string = {
1761                 .choices = sess_not_found_action_choices,
1762         } } },
1763         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1764 };
1765
1766 static
1767 bt_component_class_initialize_method_status lttng_live_component_create(
1768                 const bt_value *params,
1769                 bt_logging_level log_level,
1770                 bt_self_component *self_comp,
1771                 struct lttng_live_component **component)
1772 {
1773         struct lttng_live_component *lttng_live = NULL;
1774         const bt_value *inputs_value;
1775         const bt_value *url_value;
1776         const bt_value *value;
1777         const char *url;
1778         enum bt_param_validation_status validation_status;
1779         gchar *validation_error = NULL;
1780         bt_component_class_initialize_method_status status;
1781
1782         validation_status = bt_param_validation_validate(params, params_descr,
1783                 &validation_error);
1784         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1785                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1786                 goto error;
1787         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1788                 BT_COMP_LOGE_APPEND_CAUSE(self_comp, "%s", validation_error);
1789                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
1790                 goto error;
1791         }
1792
1793         lttng_live = g_new0(struct lttng_live_component, 1);
1794         if (!lttng_live) {
1795                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1796                 goto end;
1797         }
1798         lttng_live->log_level = log_level;
1799         lttng_live->self_comp = self_comp;
1800         lttng_live->max_query_size = MAX_QUERY_SIZE;
1801         lttng_live->has_msg_iter = false;
1802
1803         inputs_value =
1804                 bt_value_map_borrow_entry_value_const(params, INPUTS_PARAM);
1805         url_value =
1806                 bt_value_array_borrow_element_by_index_const(inputs_value, 0);
1807         url = bt_value_string_get(url_value);
1808
1809         lttng_live->params.url = g_string_new(url);
1810         if (!lttng_live->params.url) {
1811                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1812                 goto error;
1813         }
1814
1815         value = bt_value_map_borrow_entry_value_const(params,
1816                 SESS_NOT_FOUND_ACTION_PARAM);
1817         if (value) {
1818                 lttng_live->params.sess_not_found_act =
1819                         parse_session_not_found_action_param(value);
1820         } else {
1821                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1822                         "defaulting to `%s`.",
1823                         SESS_NOT_FOUND_ACTION_PARAM,
1824                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1825                 lttng_live->params.sess_not_found_act =
1826                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1827         }
1828
1829         status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;
1830         goto end;
1831
1832 error:
1833         lttng_live_component_destroy_data(lttng_live);
1834         lttng_live = NULL;
1835 end:
1836         g_free(validation_error);
1837
1838         *component = lttng_live;
1839         return status;
1840 }
1841
1842 BT_HIDDEN
1843 bt_component_class_initialize_method_status lttng_live_component_init(
1844                 bt_self_component_source *self_comp_src,
1845                 bt_self_component_source_configuration *config,
1846                 const bt_value *params,
1847                 __attribute__((unused)) void *init_method_data)
1848 {
1849         struct lttng_live_component *lttng_live;
1850         bt_component_class_initialize_method_status ret;
1851         bt_self_component *self_comp =
1852                 bt_self_component_source_as_self_component(self_comp_src);
1853         bt_logging_level log_level = bt_component_get_logging_level(
1854                 bt_self_component_as_component(self_comp));
1855         bt_self_component_add_port_status add_port_status;
1856
1857         ret = lttng_live_component_create(params, log_level, self_comp, &lttng_live);
1858         if (ret != BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK) {
1859                 goto error;
1860         }
1861
1862         add_port_status = bt_self_component_source_add_output_port(
1863                 self_comp_src, "out", NULL, NULL);
1864         if (add_port_status != BT_SELF_COMPONENT_ADD_PORT_STATUS_OK) {
1865                 ret = (int) add_port_status;
1866                 goto end;
1867         }
1868
1869         bt_self_component_set_data(self_comp, lttng_live);
1870         goto end;
1871
1872 error:
1873         lttng_live_component_destroy_data(lttng_live);
1874         lttng_live = NULL;
1875 end:
1876         return ret;
1877 }