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 <unistd.h>
  39
  40 #include "common/assert.h"
  41 #include <babeltrace2/babeltrace.h>
  42 #include "compat/compiler.h"
  43 #include <babeltrace2/types.h>
  44
  45 #include "plugins/common/muxing/muxing.h"
  46
  47 #include "data-stream.h"
  48 #include "metadata.h"
  49 #include "lttng-live.h"
  50
  51 #define MAX_QUERY_SIZE                      (256*1024)
  52 #define URL_PARAM                           "url"
  53 #define INPUTS_PARAM                        "inputs"
  54 #define SESS_NOT_FOUND_ACTION_PARAM         "session-not-found-action"
  55 #define SESS_NOT_FOUND_ACTION_CONTINUE_STR  "continue"
  56 #define SESS_NOT_FOUND_ACTION_FAIL_STR      "fail"
  57 #define SESS_NOT_FOUND_ACTION_END_STR       "end"
  58
  59 #define print_dbg(fmt, ...)     BT_COMP_LOGD(fmt, ## __VA_ARGS__)
  60
  61 static
  62 const char *print_live_iterator_status(enum lttng_live_iterator_status status)
  63 {
  64         switch (status) {
  65         case LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
  66                 return "LTTNG_LIVE_ITERATOR_STATUS_CONTINUE";
  67         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
  68                 return "LTTNG_LIVE_ITERATOR_STATUS_AGAIN";
  69         case LTTNG_LIVE_ITERATOR_STATUS_END:
  70                 return "LTTNG_LIVE_ITERATOR_STATUS_END";
  71         case LTTNG_LIVE_ITERATOR_STATUS_OK:
  72                 return "LTTNG_LIVE_ITERATOR_STATUS_OK";
  73         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
  74                 return "LTTNG_LIVE_ITERATOR_STATUS_INVAL";
  75         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
  76                 return "LTTNG_LIVE_ITERATOR_STATUS_ERROR";
  77         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
  78                 return "LTTNG_LIVE_ITERATOR_STATUS_NOMEM";
  79         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
  80                 return "LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED";
  81         default:
  82                 abort();
  83         }
  84 }
  85
  86 static
  87 const char *print_state(struct lttng_live_stream_iterator *s)
  88 {
  89         switch (s->state) {
  90         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
  91                 return "ACTIVE_NO_DATA";
  92         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
  93                 return "QUIESCENT_NO_DATA";
  94         case LTTNG_LIVE_STREAM_QUIESCENT:
  95                 return "QUIESCENT";
  96         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
  97                 return "ACTIVE_DATA";
  98         case LTTNG_LIVE_STREAM_EOF:
  99                 return "EOF";
 100         default:
 101                 return "ERROR";
 102         }
 103 }
 104
 105 #define print_stream_state(live_stream_iter) \
 106         do { \
 107                 BT_COMP_LOGD("stream state %s last_inact_ts %" PRId64  \
 108                         ", curr_inact_ts %" PRId64, \
 109                         print_state(live_stream_iter), \
 110                         live_stream_iter->last_inactivity_ts, \
 111                         live_stream_iter->current_inactivity_ts); \
 112         } while (0);
 113
 114 BT_HIDDEN
 115 bool lttng_live_graph_is_canceled(struct lttng_live_msg_iter *msg_iter)
 116 {
 117         bool ret;
 118
 119         if (!msg_iter) {
 120                 ret = false;
 121                 goto end;
 122         }
 123
 124         ret = bt_self_message_iterator_is_interrupted(
 125                 msg_iter->self_msg_iter);
 126
 127 end:
 128         return ret;
 129 }
 130
 131 static
 132 struct lttng_live_trace *lttng_live_find_trace(struct lttng_live_session *session,
 133                 uint64_t trace_id)
 134 {
 135         uint64_t trace_idx;
 136         struct lttng_live_trace *ret_trace = NULL;
 137
 138         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 139                 struct lttng_live_trace *trace =
 140                         g_ptr_array_index(session->traces, trace_idx);
 141                 if (trace->id == trace_id) {
 142                         ret_trace = trace;
 143                         goto end;
 144                 }
 145         }
 146
 147 end:
 148         return ret_trace;
 149 }
 150
 151 static
 152 void lttng_live_destroy_trace(struct lttng_live_trace *trace)
 153 {
 154         bt_logging_level log_level = trace->log_level;
 155         bt_self_component *self_comp = trace->self_comp;
 156
 157         BT_COMP_LOGD("Destroy lttng_live_trace");
 158
 159         BT_ASSERT(trace->stream_iterators);
 160         g_ptr_array_free(trace->stream_iterators, TRUE);
 161
 162         BT_TRACE_PUT_REF_AND_RESET(trace->trace);
 163         BT_TRACE_CLASS_PUT_REF_AND_RESET(trace->trace_class);
 164
 165         lttng_live_metadata_fini(trace);
 166         g_free(trace);
 167 }
 168
 169 static
 170 struct lttng_live_trace *lttng_live_create_trace(struct lttng_live_session *session,
 171                 uint64_t trace_id)
 172 {
 173         struct lttng_live_trace *trace = NULL;
 174         bt_logging_level log_level = session->log_level;
 175         bt_self_component *self_comp = session->self_comp;
 176
 177         trace = g_new0(struct lttng_live_trace, 1);
 178         if (!trace) {
 179                 goto error;
 180         }
 181         trace->log_level = session->log_level;
 182         trace->self_comp = session->self_comp;
 183         trace->session = session;
 184         trace->id = trace_id;
 185         trace->trace_class = NULL;
 186         trace->trace = NULL;
 187         trace->stream_iterators = g_ptr_array_new_with_free_func(
 188                         (GDestroyNotify) lttng_live_stream_iterator_destroy);
 189         BT_ASSERT(trace->stream_iterators);
 190         trace->new_metadata_needed = true;
 191         g_ptr_array_add(session->traces, trace);
 192
 193         BT_COMP_LOGI("Create trace");
 194         goto end;
 195 error:
 196         g_free(trace);
 197         trace = NULL;
 198 end:
 199         return trace;
 200 }
 201
 202 BT_HIDDEN
 203 struct lttng_live_trace *lttng_live_borrow_trace(
 204                 struct lttng_live_session *session, uint64_t trace_id)
 205 {
 206         struct lttng_live_trace *trace;
 207
 208         trace = lttng_live_find_trace(session, trace_id);
 209         if (trace) {
 210                 goto end;
 211         }
 212
 213         /* The session is the owner of the newly created trace. */
 214         trace = lttng_live_create_trace(session, trace_id);
 215
 216 end:
 217         return trace;
 218 }
 219
 220 BT_HIDDEN
 221 int lttng_live_add_session(struct lttng_live_msg_iter *lttng_live_msg_iter,
 222                 uint64_t session_id, const char *hostname,
 223                 const char *session_name)
 224 {
 225         int ret = 0;
 226         struct lttng_live_session *session;
 227         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 228         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 229
 230         session = g_new0(struct lttng_live_session, 1);
 231         if (!session) {
 232                 goto error;
 233         }
 234
 235         session->log_level = lttng_live_msg_iter->log_level;
 236         session->self_comp = lttng_live_msg_iter->self_comp;
 237         session->id = session_id;
 238         session->traces = g_ptr_array_new_with_free_func(
 239                         (GDestroyNotify) lttng_live_destroy_trace);
 240         BT_ASSERT(session->traces);
 241         session->lttng_live_msg_iter = lttng_live_msg_iter;
 242         session->new_streams_needed = true;
 243         session->hostname = g_string_new(hostname);
 244         BT_ASSERT(session->hostname);
 245
 246         session->session_name = g_string_new(session_name);
 247         BT_ASSERT(session->session_name);
 248
 249         BT_COMP_LOGI("Reading from session: %" PRIu64 " hostname: %s session_name: %s",
 250                 session->id, hostname, session_name);
 251         g_ptr_array_add(lttng_live_msg_iter->sessions, session);
 252         goto end;
 253 error:
 254         BT_COMP_LOGE("Error adding session");
 255         g_free(session);
 256         ret = -1;
 257 end:
 258         return ret;
 259 }
 260
 261 static
 262 void lttng_live_destroy_session(struct lttng_live_session *session)
 263 {
 264         bt_logging_level log_level;
 265         bt_self_component *self_comp;
 266
 267         if (!session) {
 268                 goto end;
 269         }
 270
 271         log_level = session->log_level;
 272         self_comp = session->self_comp;
 273         BT_COMP_LOGD("Destroy lttng live session");
 274         if (session->id != -1ULL) {
 275                 if (lttng_live_detach_session(session)) {
 276                         if (session->lttng_live_msg_iter &&
 277                                         !lttng_live_graph_is_canceled(
 278                                                 session->lttng_live_msg_iter)) {
 279                                 /* Old relayd cannot detach sessions. */
 280                                 BT_COMP_LOGD("Unable to detach lttng live session %" PRIu64,
 281                                         session->id);
 282                         }
 283                 }
 284                 session->id = -1ULL;
 285         }
 286
 287         if (session->traces) {
 288                 g_ptr_array_free(session->traces, TRUE);
 289         }
 290
 291         if (session->hostname) {
 292                 g_string_free(session->hostname, TRUE);
 293         }
 294         if (session->session_name) {
 295                 g_string_free(session->session_name, TRUE);
 296         }
 297         g_free(session);
 298
 299 end:
 300         return;
 301 }
 302
 303 static
 304 void lttng_live_msg_iter_destroy(struct lttng_live_msg_iter *lttng_live_msg_iter)
 305 {
 306         if (!lttng_live_msg_iter) {
 307                 goto end;
 308         }
 309
 310         if (lttng_live_msg_iter->sessions) {
 311                 g_ptr_array_free(lttng_live_msg_iter->sessions, TRUE);
 312         }
 313
 314         BT_OBJECT_PUT_REF_AND_RESET(lttng_live_msg_iter->viewer_connection);
 315         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp);
 316         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp->has_msg_iter);
 317
 318         /* All stream iterators must be destroyed at this point. */
 319         BT_ASSERT(lttng_live_msg_iter->active_stream_iter == 0);
 320         lttng_live_msg_iter->lttng_live_comp->has_msg_iter = false;
 321
 322         g_free(lttng_live_msg_iter);
 323
 324 end:
 325         return;
 326 }
 327
 328 BT_HIDDEN
 329 void lttng_live_msg_iter_finalize(bt_self_message_iterator *self_msg_iter)
 330 {
 331         struct lttng_live_msg_iter *lttng_live_msg_iter;
 332
 333         BT_ASSERT(self_msg_iter);
 334
 335         lttng_live_msg_iter = bt_self_message_iterator_get_data(self_msg_iter);
 336         BT_ASSERT(lttng_live_msg_iter);
 337         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
 338 }
 339
 340 static
 341 enum lttng_live_iterator_status lttng_live_iterator_next_check_stream_state(
 342                 struct lttng_live_stream_iterator *lttng_live_stream)
 343 {
 344         bt_logging_level log_level = lttng_live_stream->log_level;
 345         bt_self_component *self_comp = lttng_live_stream->self_comp;
 346
 347         switch (lttng_live_stream->state) {
 348         case LTTNG_LIVE_STREAM_QUIESCENT:
 349         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
 350                 break;
 351         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
 352                 /* Invalid state. */
 353                 BT_COMP_LOGF("Unexpected stream state \"ACTIVE_NO_DATA\"");
 354                 abort();
 355         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
 356                 /* Invalid state. */
 357                 BT_COMP_LOGF("Unexpected stream state \"QUIESCENT_NO_DATA\"");
 358                 abort();
 359         case LTTNG_LIVE_STREAM_EOF:
 360                 break;
 361         }
 362         return LTTNG_LIVE_ITERATOR_STATUS_OK;
 363 }
 364
 365 /*
 366  * For active no data stream, fetch next data. It can be either:
 367  * - quiescent: need to put it in the prio heap at quiescent end
 368  *   timestamp,
 369  * - have data: need to wire up first event into the prio heap,
 370  * - have no data on this stream at this point: need to retry (AGAIN) or
 371  *   return EOF.
 372  */
 373 static
 374 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_no_data_stream(
 375                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 376                 struct lttng_live_stream_iterator *lttng_live_stream)
 377 {
 378         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 379         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 380         enum lttng_live_iterator_status ret =
 381                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 382         struct packet_index index;
 383         enum lttng_live_stream_state orig_state = lttng_live_stream->state;
 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(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         int ret = 0;
 441
 442         if (!session->attached) {
 443                 ret = lttng_live_attach_session(session);
 444                 if (ret) {
 445                         if (lttng_live_msg_iter && lttng_live_graph_is_canceled(
 446                                         lttng_live_msg_iter)) {
 447                                 status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 448                         } else {
 449                                 status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 450                         }
 451                         goto end;
 452                 }
 453         }
 454
 455         status = lttng_live_get_new_streams(session);
 456         if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 457                         status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 458                 goto end;
 459         }
 460         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 461                 struct lttng_live_trace *trace =
 462                         g_ptr_array_index(session->traces, trace_idx);
 463
 464                 status = lttng_live_metadata_update(trace);
 465                 if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 466                                 status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 467                         goto end;
 468                 }
 469         }
 470         status = lttng_live_lazy_msg_init(session);
 471
 472 end:
 473         return status;
 474 }
 475
 476 BT_HIDDEN
 477 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 478 {
 479         uint64_t session_idx;
 480
 481         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 482                         session_idx++) {
 483                 struct lttng_live_session *session =
 484                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 485                 session->new_streams_needed = true;
 486         }
 487 }
 488
 489 static
 490 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 491 {
 492         uint64_t session_idx, trace_idx;
 493
 494         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 495                         session_idx++) {
 496                 struct lttng_live_session *session =
 497                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 498                 session->new_streams_needed = true;
 499                 for (trace_idx = 0; trace_idx < session->traces->len;
 500                                 trace_idx++) {
 501                         struct lttng_live_trace *trace =
 502                                 g_ptr_array_index(session->traces, trace_idx);
 503                         trace->new_metadata_needed = true;
 504                 }
 505         }
 506 }
 507
 508 static
 509 enum lttng_live_iterator_status
 510 lttng_live_iterator_handle_new_streams_and_metadata(
 511                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 512 {
 513         enum lttng_live_iterator_status ret =
 514                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 515         uint64_t session_idx = 0, nr_sessions_opened = 0;
 516         struct lttng_live_session *session;
 517         enum session_not_found_action sess_not_found_act =
 518                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 519
 520         /*
 521          * In a remotely distant future, we could add a "new
 522          * session" flag to the protocol, which would tell us that we
 523          * need to query for new sessions even though we have sessions
 524          * currently ongoing.
 525          */
 526         if (lttng_live_msg_iter->sessions->len == 0) {
 527                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 528                         ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 529                         goto end;
 530                 } else {
 531                         /*
 532                          * Retry to create a viewer session for the requested
 533                          * session name.
 534                          */
 535                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
 536                                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 537                                 goto end;
 538                         }
 539                 }
 540         }
 541
 542         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 543                         session_idx++) {
 544                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 545                                 session_idx);
 546                 ret = lttng_live_get_session(lttng_live_msg_iter, session);
 547                 switch (ret) {
 548                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 549                         break;
 550                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 551                         ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 552                         break;
 553                 default:
 554                         goto end;
 555                 }
 556                 if (!session->closed) {
 557                         nr_sessions_opened++;
 558                 }
 559         }
 560 end:
 561         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK &&
 562                         sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 563                         nr_sessions_opened == 0) {
 564                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 565         }
 566         return ret;
 567 }
 568
 569 static
 570 enum lttng_live_iterator_status emit_inactivity_message(
 571                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 572                 struct lttng_live_stream_iterator *stream_iter,
 573                 bt_message **message, uint64_t timestamp)
 574 {
 575         enum lttng_live_iterator_status ret =
 576                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 577         bt_message *msg = NULL;
 578
 579         BT_ASSERT(stream_iter->trace->clock_class);
 580
 581         msg = bt_message_message_iterator_inactivity_create(
 582                         lttng_live_msg_iter->self_msg_iter,
 583                         stream_iter->trace->clock_class,
 584                         timestamp);
 585         if (!msg) {
 586                 goto error;
 587         }
 588
 589         *message = msg;
 590 end:
 591         return ret;
 592
 593 error:
 594         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 595         bt_message_put_ref(msg);
 596         goto end;
 597 }
 598
 599 static
 600 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 601                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 602                 struct lttng_live_stream_iterator *lttng_live_stream,
 603                 bt_message **message)
 604 {
 605         enum lttng_live_iterator_status ret =
 606                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 607
 608         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 609                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 610         }
 611
 612         if (lttng_live_stream->current_inactivity_ts ==
 613                         lttng_live_stream->last_inactivity_ts) {
 614                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 615                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 616                 goto end;
 617         }
 618
 619         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 620                         message, lttng_live_stream->current_inactivity_ts);
 621
 622         lttng_live_stream->last_inactivity_ts =
 623                         lttng_live_stream->current_inactivity_ts;
 624 end:
 625         return ret;
 626 }
 627
 628 static
 629 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 630                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 631                 const bt_message *msg, int64_t last_msg_ts_ns,
 632                 int64_t *ts_ns)
 633 {
 634         const bt_clock_class *clock_class = NULL;
 635         const bt_clock_snapshot *clock_snapshot = NULL;
 636         int ret = 0;
 637         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 638         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 639
 640         BT_ASSERT(msg);
 641         BT_ASSERT(ts_ns);
 642
 643         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 644                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 645                 last_msg_ts_ns);
 646
 647         switch (bt_message_get_type(msg)) {
 648         case BT_MESSAGE_TYPE_EVENT:
 649                 clock_class =
 650                         bt_message_event_borrow_stream_class_default_clock_class_const(
 651                                 msg);
 652                 BT_ASSERT(clock_class);
 653
 654                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 655                         msg);
 656                 break;
 657         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 658                 clock_class =
 659                         bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 660                         msg);
 661                 BT_ASSERT(clock_class);
 662
 663                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 664                         msg);
 665                 break;
 666         case BT_MESSAGE_TYPE_PACKET_END:
 667                 clock_class =
 668                         bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 669                         msg);
 670                 BT_ASSERT(clock_class);
 671
 672                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 673                         msg);
 674                 break;
 675         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 676                 clock_class =
 677                         bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 678                         msg);
 679                 BT_ASSERT(clock_class);
 680
 681                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 682                         msg);
 683                 break;
 684         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 685                 clock_class =
 686                         bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 687                         msg);
 688                 BT_ASSERT(clock_class);
 689
 690                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 691                         msg);
 692                 break;
 693         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 694                 clock_snapshot =
 695                         bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 696                                 msg);
 697                 break;
 698         default:
 699                 /* All the other messages have a higher priority */
 700                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 701                 *ts_ns = last_msg_ts_ns;
 702                 goto end;
 703         }
 704
 705         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 706         BT_ASSERT(clock_class);
 707
 708         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 709         if (ret) {
 710                 BT_COMP_LOGE("Cannot get nanoseconds from Epoch of clock snapshot: "
 711                         "clock-snapshot-addr=%p", clock_snapshot);
 712                 goto error;
 713         }
 714
 715         goto end;
 716
 717 error:
 718         ret = -1;
 719
 720 end:
 721         if (ret == 0) {
 722                 BT_COMP_LOGD("Found message's timestamp: "
 723                         "iter-data-addr=%p, msg-addr=%p, "
 724                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 725                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 726         }
 727
 728         return ret;
 729 }
 730
 731 static
 732 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 733                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 734                 struct lttng_live_stream_iterator *lttng_live_stream,
 735                 bt_message **message)
 736 {
 737         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 738         enum bt_msg_iter_status status;
 739         uint64_t session_idx, trace_idx;
 740         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 741         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 742
 743         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 744                         session_idx++) {
 745                 struct lttng_live_session *session =
 746                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 747
 748                 if (session->new_streams_needed) {
 749                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 750                         goto end;
 751                 }
 752                 for (trace_idx = 0; trace_idx < session->traces->len;
 753                                 trace_idx++) {
 754                         struct lttng_live_trace *trace =
 755                                 g_ptr_array_index(session->traces, trace_idx);
 756                         if (trace->new_metadata_needed) {
 757                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 758                                 goto end;
 759                         }
 760                 }
 761         }
 762
 763         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 764                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 765                 goto end;
 766         }
 767
 768         status = bt_msg_iter_get_next_message(lttng_live_stream->msg_iter,
 769                 lttng_live_msg_iter->self_msg_iter, message);
 770         switch (status) {
 771         case BT_MSG_ITER_STATUS_EOF:
 772                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 773                 break;
 774         case BT_MSG_ITER_STATUS_OK:
 775                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 776                 break;
 777         case BT_MSG_ITER_STATUS_AGAIN:
 778                 /*
 779                  * Continue immediately (end of packet). The next
 780                  * get_index may return AGAIN to delay the following
 781                  * attempt.
 782                  */
 783                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 784                 break;
 785         case BT_MSG_ITER_STATUS_INVAL:
 786                 /* No argument provided by the user, so don't return INVAL. */
 787         case BT_MSG_ITER_STATUS_ERROR:
 788         default:
 789                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 790                 BT_COMP_LOGW("CTF msg iterator return an error or failed msg_iter=%p",
 791                         lttng_live_stream->msg_iter);
 792                 break;
 793         }
 794
 795 end:
 796         return ret;
 797 }
 798
 799 static
 800 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 801                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 802                 struct lttng_live_stream_iterator *stream_iter,
 803                 bt_message **curr_msg)
 804 {
 805         enum lttng_live_iterator_status live_status =
 806                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 807         /*
 808          * The viewer has hung up on us so we are closing the stream. The
 809          * `bt_msg_iter` should simply realize that it needs to close the
 810          * stream properly by emitting the necessary stream end message.
 811          */
 812         enum bt_msg_iter_status status =
 813                 bt_msg_iter_get_next_message(stream_iter->msg_iter,
 814                         lttng_live_msg_iter->self_msg_iter, curr_msg);
 815
 816         if (status == BT_MSG_ITER_STATUS_ERROR) {
 817                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 818                 goto end;
 819         }
 820
 821         BT_ASSERT(status == BT_MSG_ITER_STATUS_OK);
 822
 823 end:
 824         return live_status;
 825 }
 826
 827 /*
 828  * helper function:
 829  *            handle_no_data_streams()
 830  *              retry:
 831  *                - for each ACTIVE_NO_DATA stream:
 832  *                  - query relayd for stream data, or quiescence info.
 833  *                    - if need metadata, get metadata, goto retry.
 834  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 835  *                  - if quiescent, move to QUIESCENT streams
 836  *                  - if fetched data, move to ACTIVE_DATA streams
 837  *                (at this point each stream either has data, or is quiescent)
 838  *
 839  *
 840  * iterator_next:
 841  *            handle_new_streams_and_metadata()
 842  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 843  *                  - query relayd for metadata
 844  *
 845  *            call handle_active_no_data_streams()
 846  *
 847  *            handle_quiescent_streams()
 848  *                - if at least one stream is ACTIVE_DATA:
 849  *                  - peek stream event with lowest timestamp -> next_ts
 850  *                  - for each quiescent stream
 851  *                    - if next_ts >= quiescent end
 852  *                      - set state to ACTIVE_NO_DATA
 853  *                - else
 854  *                  - for each quiescent stream
 855  *                      - set state to ACTIVE_NO_DATA
 856  *
 857  *            call handle_active_no_data_streams()
 858  *
 859  *            handle_active_data_streams()
 860  *                - if at least one stream is ACTIVE_DATA:
 861  *                    - get stream event with lowest timestamp from heap
 862  *                    - make that stream event the current message.
 863  *                    - move this stream heap position to its next event
 864  *                      - if we need to fetch data from relayd, move
 865  *                        stream to ACTIVE_NO_DATA.
 866  *                    - return OK
 867  *                - return AGAIN
 868  *
 869  * end criterion: ctrl-c on client. If relayd exits or the session
 870  * closes on the relay daemon side, we keep on waiting for streams.
 871  * Eventually handle --end timestamp (also an end criterion).
 872  *
 873  * When disconnected from relayd: try to re-connect endlessly.
 874  */
 875 static
 876 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 877                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 878                 struct lttng_live_stream_iterator *stream_iter,
 879                 bt_message **curr_msg)
 880 {
 881         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 882         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 883         enum lttng_live_iterator_status live_status;
 884
 885         if (stream_iter->has_stream_hung_up) {
 886                 /*
 887                  * The stream has hung up and the stream was properly closed
 888                  * during the last call to the current function. Return _END
 889                  * status now so that this stream iterator is removed for the
 890                  * stream iterator list.
 891                  */
 892                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 893                 goto end;
 894         }
 895
 896 retry:
 897         print_stream_state(stream_iter);
 898         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 899                         lttng_live_msg_iter);
 900         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 901                 goto end;
 902         }
 903         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 904                         lttng_live_msg_iter, stream_iter);
 905
 906         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 907                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 908                         /*
 909                          * We overwrite `live_status` since `curr_msg` is
 910                          * likely set to a valid message in this function.
 911                          */
 912                         live_status = lttng_live_iterator_close_stream(
 913                                 lttng_live_msg_iter, stream_iter, curr_msg);
 914                 }
 915                 goto end;
 916         }
 917         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 918                         lttng_live_msg_iter, stream_iter, curr_msg);
 919         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 920                 BT_ASSERT(!*curr_msg);
 921                 goto end;
 922         }
 923         if (*curr_msg) {
 924                 goto end;
 925         }
 926         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 927                         lttng_live_msg_iter, stream_iter, curr_msg);
 928         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 929                 BT_ASSERT(!*curr_msg);
 930         }
 931
 932 end:
 933         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 934                 goto retry;
 935         }
 936
 937         return live_status;
 938 }
 939
 940 static
 941 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 942                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 943                 struct lttng_live_trace *live_trace,
 944                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 945 {
 946         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 947         enum lttng_live_iterator_status stream_iter_status;;
 948         int64_t youngest_candidate_msg_ts = INT64_MAX;
 949         uint64_t stream_iter_idx;
 950         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 951         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 952
 953         BT_ASSERT(live_trace);
 954         BT_ASSERT(live_trace->stream_iterators);
 955         /*
 956          * Update the current message of every stream iterators of this trace.
 957          * The current msg of every stream must have a timestamp equal or
 958          * larger than the last message returned by this iterator. We must
 959          * ensure monotonicity.
 960          */
 961         stream_iter_idx = 0;
 962         while (stream_iter_idx < live_trace->stream_iterators->len) {
 963                 bool stream_iter_is_ended = false;
 964                 struct lttng_live_stream_iterator *stream_iter =
 965                         g_ptr_array_index(live_trace->stream_iterators,
 966                                         stream_iter_idx);
 967
 968                 /*
 969                  * Since we may remove elements from the GPtrArray as we
 970                  * iterate over it, it's possible to see the same element more
 971                  * than once.
 972                  */
 973                 if (stream_iter == youngest_candidate_stream_iter) {
 974                         stream_iter_idx++;
 975                         continue;
 976                 }
 977
 978                 /*
 979                  * Find if there is are now current message for this stream
 980                  * iterator get it.
 981                  */
 982                 while (!stream_iter->current_msg) {
 983                         bt_message *msg = NULL;
 984                         int64_t curr_msg_ts_ns = INT64_MAX;
 985                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
 986                                         lttng_live_msg_iter, stream_iter, &msg);
 987
 988                         BT_COMP_LOGD("live stream iterator returned status :%s",
 989                                         print_live_iterator_status(stream_iter_status));
 990                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 991                                 stream_iter_is_ended = true;
 992                                 break;
 993                         }
 994
 995                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 996                                 goto end;
 997                         }
 998
 999                         BT_ASSERT(msg);
1000
1001                         /*
1002                          * Get the timestamp in nanoseconds from origin of this
1003                          * messsage.
1004                          */
1005                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
1006                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
1007                                 &curr_msg_ts_ns);
1008
1009                         /*
1010                          * Check if the message of the current live stream
1011                          * iterator occured at the exact same time or after the
1012                          * last message returned by this component's message
1013                          * iterator. If not, we return an error.
1014                          */
1015                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
1016                                 stream_iter->current_msg = msg;
1017                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
1018                         } else {
1019                                 /*
1020                                  * We received a message in the past. To ensure
1021                                  * monotonicity, we can't send it forward.
1022                                  */
1023                                 BT_COMP_LOGE("Message's timestamp is less than "
1024                                         "lttng-live's message iterator's last "
1025                                         "returned timestamp: "
1026                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1027                                         "last-msg-ts=%" PRId64,
1028                                         lttng_live_msg_iter, curr_msg_ts_ns,
1029                                         lttng_live_msg_iter->last_msg_ts_ns);
1030                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1031                                 goto end;
1032                         }
1033                 }
1034
1035                 BT_ASSERT(stream_iter != youngest_candidate_stream_iter);
1036
1037                 if (!stream_iter_is_ended) {
1038                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1039                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1040                                 /*
1041                                  * Update the current best candidate message
1042                                  * for the stream iterator of this live trace
1043                                  * to be forwarded downstream.
1044                                  */
1045                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1046                                 youngest_candidate_stream_iter = stream_iter;
1047                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1048                                 /*
1049                                  * Order the messages in an arbitrary but
1050                                  * deterministic way.
1051                                  */
1052                                 BT_ASSERT(stream_iter != youngest_candidate_stream_iter);
1053                                 int ret = common_muxing_compare_messages(
1054                                         stream_iter->current_msg,
1055                                         youngest_candidate_stream_iter->current_msg);
1056                                 if (ret < 0) {
1057                                         /*
1058                                          * The `youngest_candidate_stream_iter->current_msg`
1059                                          * should go first. Update the next
1060                                          * iterator and the current timestamp.
1061                                          */
1062                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1063                                         youngest_candidate_stream_iter = stream_iter;
1064                                 } else if (ret == 0) {
1065                                         /*
1066                                          * Unable to pick which one should go
1067                                          * first.
1068                                          */
1069                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1070                                                 "stream-iter-addr=%p"
1071                                                 "stream-iter-addr=%p",
1072                                                 stream_iter,
1073                                                 youngest_candidate_stream_iter);
1074                                 }
1075                         }
1076
1077                         stream_iter_idx++;
1078                 } else {
1079                         /*
1080                          * The live stream iterator is ENDed. We remove that
1081                          * iterator from the list and we restart the iteration
1082                          * at the beginning of the live stream iterator array
1083                          * to because the removal will shuffle the array.
1084                          */
1085                         g_ptr_array_remove_index_fast(live_trace->stream_iterators,
1086                                 stream_iter_idx);
1087                         stream_iter_idx = 0;
1088                 }
1089         }
1090
1091         if (youngest_candidate_stream_iter) {
1092                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1093                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1094         } else {
1095                 /*
1096                  * The only case where we don't have a candidate for this trace
1097                  * is if we reached the end of all the iterators.
1098                  */
1099                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1100                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1101         }
1102
1103 end:
1104         return stream_iter_status;
1105 }
1106
1107 static
1108 enum lttng_live_iterator_status next_stream_iterator_for_session(
1109                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1110                 struct lttng_live_session *session,
1111                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1112 {
1113         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1114         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1115         enum lttng_live_iterator_status stream_iter_status;
1116         uint64_t trace_idx = 0;
1117         int64_t youngest_candidate_msg_ts = INT64_MAX;
1118         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1119
1120         /*
1121          * Make sure we are attached to the session and look for new streams
1122          * and metadata.
1123          */
1124         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1125         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1126                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1127                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1128                 goto end;
1129         }
1130
1131         BT_ASSERT(session->traces);
1132
1133         /*
1134          * Use while loops here rather then for loops so we can restart the
1135          * iteration if an element is removed from the array during the
1136          * looping.
1137          */
1138         while (trace_idx < session->traces->len) {
1139                 bool trace_is_ended = false;
1140                 struct lttng_live_stream_iterator *stream_iter;
1141                 struct lttng_live_trace *trace =
1142                         g_ptr_array_index(session->traces, trace_idx);
1143
1144                 stream_iter_status = next_stream_iterator_for_trace(
1145                         lttng_live_msg_iter, trace, &stream_iter);
1146                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1147                         /*
1148                          * All the live stream iterators for this trace are
1149                          * ENDed. Remove the trace from this session.
1150                          */
1151                         trace_is_ended = true;
1152                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1153                         goto end;
1154                 }
1155
1156                 if (!trace_is_ended) {
1157                         BT_ASSERT(stream_iter);
1158
1159                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1160                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1161                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1162                                 youngest_candidate_stream_iter = stream_iter;
1163                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1164                                 /*
1165                                  * Order the messages in an arbitrary but
1166                                  * deterministic way.
1167                                  */
1168                                 int ret = common_muxing_compare_messages(
1169                                         stream_iter->current_msg,
1170                                         youngest_candidate_stream_iter->current_msg);
1171                                 if (ret < 0) {
1172                                         /*
1173                                          * The `youngest_candidate_stream_iter->current_msg`
1174                                          * should go first. Update the next iterator
1175                                          * and the current timestamp.
1176                                          */
1177                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1178                                         youngest_candidate_stream_iter = stream_iter;
1179                                 } else if (ret == 0) {
1180                                         /* Unable to pick which one should go first. */
1181                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1182                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1183                                                 stream_iter, youngest_candidate_stream_iter);
1184                                 }
1185                         }
1186                         trace_idx++;
1187                 } else {
1188                         g_ptr_array_remove_index_fast(session->traces, trace_idx);
1189                         trace_idx = 0;
1190                 }
1191         }
1192         if (youngest_candidate_stream_iter) {
1193                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1194                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1195         } else {
1196                 /*
1197                  * The only cases where we don't have a candidate for this
1198                  * trace is:
1199                  *  1. if we reached the end of all the iterators of all the
1200                  *  traces of this session,
1201                  *  2. if we never had live stream iterator in the first place.
1202                  *
1203                  * In either cases, we return END.
1204                  */
1205                 BT_ASSERT(session->traces->len == 0);
1206                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1207         }
1208 end:
1209         return stream_iter_status;
1210 }
1211
1212 static inline
1213 void put_messages(bt_message_array_const msgs, uint64_t count)
1214 {
1215         uint64_t i;
1216
1217         for (i = 0; i < count; i++) {
1218                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1219         }
1220 }
1221
1222 BT_HIDDEN
1223 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1224                 bt_self_message_iterator *self_msg_it,
1225                 bt_message_array_const msgs, uint64_t capacity,
1226                 uint64_t *count)
1227 {
1228         bt_component_class_message_iterator_next_method_status status;
1229         struct lttng_live_msg_iter *lttng_live_msg_iter =
1230                 bt_self_message_iterator_get_data(self_msg_it);
1231         struct lttng_live_component *lttng_live =
1232                 lttng_live_msg_iter->lttng_live_comp;
1233         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1234         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1235         enum lttng_live_iterator_status stream_iter_status;
1236         uint64_t session_idx;
1237
1238         *count = 0;
1239
1240         BT_ASSERT(lttng_live_msg_iter);
1241
1242         /*
1243          * Clear all the invalid message reference that might be left over in
1244          * the output array.
1245          */
1246         memset(msgs, 0, capacity * sizeof(*msgs));
1247
1248         /*
1249          * If no session are exposed on the relay found at the url provided by
1250          * the user, session count will be 0. In this case, we return status
1251          * end to return gracefully.
1252          */
1253         if (lttng_live_msg_iter->sessions->len == 0) {
1254                 if (lttng_live->params.sess_not_found_act !=
1255                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1256                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1257                         goto no_session;
1258                 } else {
1259                         /*
1260                          * The are no more active session for this session
1261                          * name. Retry to create a viewer session for the
1262                          * requested session name.
1263                          */
1264                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1265                                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1266                                 goto no_session;
1267                         }
1268                 }
1269         }
1270
1271         if (lttng_live_msg_iter->active_stream_iter == 0) {
1272                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1273         }
1274
1275         /*
1276          * Here the muxing of message is done.
1277          *
1278          * We need to iterate over all the streams of all the traces of all the
1279          * viewer sessions in order to get the message with the smallest
1280          * timestamp. In this case, a session is a viewer session and there is
1281          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1282          * kernel). Each viewer session can have multiple traces, for example,
1283          * 64bit UST viewer sessions could have multiple per-pid traces.
1284          *
1285          * We iterate over the streams of each traces to update and see what is
1286          * their next message's timestamp. From those timestamps, we select the
1287          * message with the smallest timestamp as the best candidate message
1288          * for that trace and do the same thing across all the sessions.
1289          *
1290          * We then compare the timestamp of best candidate message of all the
1291          * sessions to pick the message with the smallest timestamp and we
1292          * return it.
1293          */
1294         while (*count < capacity) {
1295                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1296                           *candidate_stream_iter = NULL;
1297                 int64_t youngest_msg_ts_ns = INT64_MAX;
1298
1299                 BT_ASSERT(lttng_live_msg_iter->sessions);
1300                 session_idx = 0;
1301                 /*
1302                  * Use a while loop instead of a for loop so we can restart the
1303                  * iteration if we remove an element. We can safely call
1304                  * next_stream_iterator_for_session() multiple times on the
1305                  * same session as we only fetch a new message if there is no
1306                  * current next message for each live stream iterator.
1307                  * If all live stream iterator of that session already have a
1308                  * current next message, the function will simply exit return
1309                  * the same candidate live stream iterator every time.
1310                  */
1311                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1312                         struct lttng_live_session *session =
1313                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1314                                         session_idx);
1315
1316                         /* Find the best candidate message to send downstream. */
1317                         stream_iter_status = next_stream_iterator_for_session(
1318                                 lttng_live_msg_iter, session,
1319                                 &candidate_stream_iter);
1320
1321                         /* If we receive an END status, it means that either:
1322                          * - Those traces never had active streams (UST with no
1323                          *   data produced yet),
1324                          * - All live stream iterators have ENDed.*/
1325                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1326                                 if (session->closed && session->traces->len == 0) {
1327                                         /*
1328                                          * Remove the session from the list and restart the
1329                                          * iteration at the beginning of the array since the
1330                                          * removal shuffle the elements of the array.
1331                                          */
1332                                         g_ptr_array_remove_index_fast(
1333                                                 lttng_live_msg_iter->sessions,
1334                                                 session_idx);
1335                                         session_idx = 0;
1336                                 } else {
1337                                         session_idx++;
1338                                 }
1339                                 continue;
1340                         }
1341
1342                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1343                                 goto end;
1344                         }
1345
1346                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1347                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1348                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1349                                 youngest_stream_iter = candidate_stream_iter;
1350                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1351                                 /*
1352                                  * The currently selected message to be sent
1353                                  * downstream next has the exact same timestamp
1354                                  * that of the current candidate message. We
1355                                  * must break the tie in a predictable manner.
1356                                  */
1357                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1358                                 /*
1359                                  * Order the messages in an arbitrary but
1360                                  * deterministic way.
1361                                  */
1362                                 int ret = common_muxing_compare_messages(
1363                                         candidate_stream_iter->current_msg,
1364                                         youngest_stream_iter->current_msg);
1365                                 if (ret < 0) {
1366                                         /*
1367                                          * The `candidate_stream_iter->current_msg`
1368                                          * should go first. Update the next
1369                                          * iterator and the current timestamp.
1370                                          */
1371                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1372                                         youngest_stream_iter = candidate_stream_iter;
1373                                 } else if (ret == 0) {
1374                                         /* Unable to pick which one should go first. */
1375                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1376                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1377                                                 youngest_stream_iter, candidate_stream_iter);
1378                                 }
1379                         }
1380
1381                         session_idx++;
1382                 }
1383
1384                 if (!youngest_stream_iter) {
1385                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1386                         goto end;
1387                 }
1388
1389                 BT_ASSERT(youngest_stream_iter->current_msg);
1390                 /* Ensure monotonicity. */
1391                 BT_ASSERT(lttng_live_msg_iter->last_msg_ts_ns <=
1392                         youngest_stream_iter->current_msg_ts_ns);
1393
1394                 /*
1395                  * Insert the next message to the message batch. This will set
1396                  * stream iterator current messsage to NULL so that next time
1397                  * we fetch the next message of that stream iterator
1398                  */
1399                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1400                 (*count)++;
1401
1402                 /* Update the last timestamp in nanoseconds sent downstream. */
1403                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1404                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1405
1406                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1407         }
1408 end:
1409         switch (stream_iter_status) {
1410         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1411         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1412                 if (*count > 0) {
1413                         /*
1414                          * We received a again status but we have some messages
1415                          * to send downstream. We send them and return OK for
1416                          * now. On the next call we return again if there are
1417                          * still no new message to send.
1418                          */
1419                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1420                 } else {
1421                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1422                 }
1423                 break;
1424         case LTTNG_LIVE_ITERATOR_STATUS_END:
1425                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1426                 break;
1427         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1428                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1429                 break;
1430         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1431         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1432         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1433                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1434                 /* Put all existing messages on error. */
1435                 put_messages(msgs, *count);
1436                 break;
1437         default:
1438                 abort();
1439         }
1440
1441 no_session:
1442         return status;
1443 }
1444
1445 BT_HIDDEN
1446 bt_component_class_message_iterator_init_method_status lttng_live_msg_iter_init(
1447                 bt_self_message_iterator *self_msg_it,
1448                 bt_self_message_iterator_configuration *config,
1449                 bt_self_component_source *self_comp_src,
1450                 bt_self_component_port_output *self_port)
1451 {
1452         bt_component_class_message_iterator_init_method_status ret =
1453                 BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INIT_METHOD_STATUS_OK;
1454         bt_self_component *self_comp =
1455                 bt_self_component_source_as_self_component(self_comp_src);
1456         struct lttng_live_component *lttng_live;
1457         struct lttng_live_msg_iter *lttng_live_msg_iter;
1458         bt_logging_level log_level;
1459
1460         BT_ASSERT(self_msg_it);
1461
1462         lttng_live = bt_self_component_get_data(self_comp);
1463         log_level = lttng_live->log_level;
1464         self_comp = lttng_live->self_comp;
1465
1466         /* There can be only one downstream iterator at the same time. */
1467         BT_ASSERT(!lttng_live->has_msg_iter);
1468         lttng_live->has_msg_iter = true;
1469
1470         lttng_live_msg_iter = g_new0(struct lttng_live_msg_iter, 1);
1471         if (!lttng_live_msg_iter) {
1472                 ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INIT_METHOD_STATUS_ERROR;
1473                 goto end;
1474         }
1475
1476         lttng_live_msg_iter->log_level = lttng_live->log_level;
1477         lttng_live_msg_iter->self_comp = lttng_live->self_comp;
1478         lttng_live_msg_iter->lttng_live_comp = lttng_live;
1479         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1480
1481         lttng_live_msg_iter->active_stream_iter = 0;
1482         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1483         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1484                 (GDestroyNotify) lttng_live_destroy_session);
1485         BT_ASSERT(lttng_live_msg_iter->sessions);
1486
1487         lttng_live_msg_iter->viewer_connection =
1488                 live_viewer_connection_create(lttng_live->params.url->str, false,
1489                         lttng_live_msg_iter, log_level);
1490         if (!lttng_live_msg_iter->viewer_connection) {
1491                 goto error;
1492         }
1493
1494         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1495                 goto error;
1496         }
1497         if (lttng_live_msg_iter->sessions->len == 0) {
1498                 switch (lttng_live->params.sess_not_found_act) {
1499                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1500                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1501                                 "session. Keep trying to connect because of "
1502                                 "%s=\"%s\" component parameter: url=\"%s\"",
1503                                 SESS_NOT_FOUND_ACTION_PARAM,
1504                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1505                                 lttng_live->params.url->str);
1506                         break;
1507                 case SESSION_NOT_FOUND_ACTION_FAIL:
1508                         BT_COMP_LOGE("Unable to connect to the requested live viewer "
1509                                 "session. Fail the message iterator"
1510                                 "initialization because of %s=\"%s\" "
1511                                 "component parameter: url =\"%s\"",
1512                                 SESS_NOT_FOUND_ACTION_PARAM,
1513                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1514                                 lttng_live->params.url->str);
1515                         goto error;
1516                 case SESSION_NOT_FOUND_ACTION_END:
1517                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1518                                 "session. End gracefully at the first _next() "
1519                                 "call because of %s=\"%s\" component parameter: "
1520                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1521                                 SESS_NOT_FOUND_ACTION_END_STR,
1522                                 lttng_live->params.url->str);
1523                         break;
1524                 case SESSION_NOT_FOUND_ACTION_UNKNOWN:
1525                 default:
1526                         /* Fallthrough */
1527                         BT_COMP_LOGE("Unknown action for session not found"
1528                                 "error. Fail the message iterator"
1529                                 "initialization because of %s=\"%s\" "
1530                                 "component parameter: url =\"%s\"",
1531                                 SESS_NOT_FOUND_ACTION_PARAM,
1532                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1533                                 lttng_live->params.url->str);
1534                         break;
1535                 }
1536         }
1537
1538         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1539
1540         goto end;
1541 error:
1542         ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INIT_METHOD_STATUS_ERROR;
1543         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1544 end:
1545         return ret;
1546 }
1547
1548 static
1549 bt_component_class_query_method_status lttng_live_query_list_sessions(
1550                 const bt_value *params, const bt_value **result,
1551                 bt_logging_level log_level)
1552 {
1553         bt_component_class_query_method_status status =
1554                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1555         const bt_value *url_value = NULL;
1556         const char *url;
1557         struct live_viewer_connection *viewer_connection = NULL;
1558         bt_self_component *self_comp = NULL;
1559
1560         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1561         if (!url_value) {
1562                 BT_COMP_LOGE("Mandatory `%s` parameter missing", URL_PARAM);
1563                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1564                 goto error;
1565         }
1566
1567         if (!bt_value_is_string(url_value)) {
1568                 BT_COMP_LOGE("`%s` parameter is required to be a string value",
1569                         URL_PARAM);
1570                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1571                 goto error;
1572         }
1573
1574         url = bt_value_string_get(url_value);
1575
1576         viewer_connection = live_viewer_connection_create(url, true, NULL,
1577                 log_level);
1578         if (!viewer_connection) {
1579                 goto error;
1580         }
1581
1582         status = live_viewer_connection_list_sessions(viewer_connection,
1583                         result);
1584         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1585                 goto error;
1586         }
1587
1588         goto end;
1589
1590 error:
1591         BT_VALUE_PUT_REF_AND_RESET(*result);
1592
1593         if (status >= 0) {
1594                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1595         }
1596
1597 end:
1598         if (viewer_connection) {
1599                 live_viewer_connection_destroy(viewer_connection);
1600         }
1601         return status;
1602 }
1603
1604 static
1605 bt_component_class_query_method_status lttng_live_query_support_info(
1606                 const bt_value *params, const bt_value **result,
1607                 bt_logging_level log_level)
1608 {
1609         bt_component_class_query_method_status status =
1610                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1611         const bt_value *input_type_value;
1612         const bt_value *input_value;
1613         double weight = 0;
1614         struct bt_common_lttng_live_url_parts parts = { 0 };
1615
1616         /* Used by the logging macros */
1617         __attribute__((unused)) bt_self_component *self_comp = NULL;
1618
1619         *result = NULL;
1620         input_type_value = bt_value_map_borrow_entry_value_const(params,
1621                 "type");
1622         if (!input_type_value) {
1623                 BT_COMP_LOGE("Missing expected `type` parameter.");
1624                 goto error;
1625         }
1626
1627         if (!bt_value_is_string(input_type_value)) {
1628                 BT_COMP_LOGE("`type` parameter is not a string value.");
1629                 goto error;
1630         }
1631
1632         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1633                 /* We don't handle file system paths */
1634                 goto create_result;
1635         }
1636
1637         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1638         if (!input_value) {
1639                 BT_COMP_LOGE("Missing expected `input` parameter.");
1640                 goto error;
1641         }
1642
1643         if (!bt_value_is_string(input_value)) {
1644                 BT_COMP_LOGE("`input` parameter is not a string value.");
1645                 goto error;
1646         }
1647
1648         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1649                 NULL, 0);
1650         if (parts.session_name) {
1651                 /*
1652                  * Looks pretty much like an LTTng live URL: we got the
1653                  * session name part, which forms a complete URL.
1654                  */
1655                 weight = .75;
1656         }
1657
1658 create_result:
1659         *result = bt_value_real_create_init(weight);
1660         if (!*result) {
1661                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1662                 goto error;
1663         }
1664
1665         goto end;
1666
1667 error:
1668         if (status >= 0) {
1669                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1670         }
1671
1672         BT_ASSERT(!*result);
1673
1674 end:
1675         bt_common_destroy_lttng_live_url_parts(&parts);
1676         return status;
1677 }
1678
1679 BT_HIDDEN
1680 bt_component_class_query_method_status lttng_live_query(
1681                 bt_self_component_class_source *comp_class,
1682                 bt_private_query_executor *priv_query_exec,
1683                 const char *object, const bt_value *params,
1684                 __attribute__((unused)) void *method_data,
1685                 const bt_value **result)
1686 {
1687         bt_component_class_query_method_status status =
1688                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1689         bt_self_component *self_comp = NULL;
1690         bt_logging_level log_level = bt_query_executor_get_logging_level(
1691                 bt_private_query_executor_as_query_executor_const(
1692                         priv_query_exec));
1693
1694         if (strcmp(object, "sessions") == 0) {
1695                 status = lttng_live_query_list_sessions(params, result,
1696                         log_level);
1697         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1698                 status = lttng_live_query_support_info(params, result,
1699                         log_level);
1700         } else {
1701                 BT_COMP_LOGI("Unknown query object `%s`", object);
1702                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1703                 goto end;
1704         }
1705
1706 end:
1707         return status;
1708 }
1709
1710 static
1711 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1712 {
1713         if (!lttng_live) {
1714                 return;
1715         }
1716         if (lttng_live->params.url) {
1717                 g_string_free(lttng_live->params.url, TRUE);
1718         }
1719         g_free(lttng_live);
1720 }
1721
1722 BT_HIDDEN
1723 void lttng_live_component_finalize(bt_self_component_source *component)
1724 {
1725         void *data = bt_self_component_get_data(
1726                         bt_self_component_source_as_self_component(component));
1727
1728         if (!data) {
1729                 return;
1730         }
1731         lttng_live_component_destroy_data(data);
1732 }
1733
1734 static
1735 enum session_not_found_action parse_session_not_found_action_param(
1736         const bt_value *no_session_param)
1737 {
1738         enum session_not_found_action action;
1739         const char *no_session_act_str;
1740         no_session_act_str = bt_value_string_get(no_session_param);
1741         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1742                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1743         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1744                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1745         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0) {
1746                 action = SESSION_NOT_FOUND_ACTION_END;
1747         } else {
1748                 action = SESSION_NOT_FOUND_ACTION_UNKNOWN;
1749         }
1750
1751         return action;
1752 }
1753
1754 struct lttng_live_component *lttng_live_component_create(const bt_value *params,
1755                 bt_logging_level log_level, bt_self_component *self_comp)
1756 {
1757         struct lttng_live_component *lttng_live;
1758         const bt_value *inputs_value;
1759         const bt_value *url_value;
1760         const bt_value *value;
1761         const char *url;
1762
1763         lttng_live = g_new0(struct lttng_live_component, 1);
1764         if (!lttng_live) {
1765                 goto end;
1766         }
1767         lttng_live->log_level = log_level;
1768         lttng_live->self_comp = self_comp;
1769         lttng_live->max_query_size = MAX_QUERY_SIZE;
1770         lttng_live->has_msg_iter = false;
1771
1772         inputs_value = bt_value_map_borrow_entry_value_const(params,
1773                 INPUTS_PARAM);
1774         if (!inputs_value) {
1775                 BT_COMP_LOGE("Mandatory `%s` parameter missing", INPUTS_PARAM);
1776                 goto error;
1777         }
1778
1779         if (!bt_value_is_array(inputs_value)) {
1780                 BT_COMP_LOGE("`%s` parameter is required to be an array value",
1781                         INPUTS_PARAM);
1782                 goto error;
1783         }
1784
1785         if (bt_value_array_get_length(inputs_value) != 1) {
1786                 BT_COMP_LOGE("`%s` parameter's length is required to be 1",
1787                         INPUTS_PARAM);
1788                 goto error;
1789         }
1790
1791         url_value = bt_value_array_borrow_element_by_index_const(inputs_value,
1792                 0);
1793         BT_ASSERT(url_value);
1794
1795         if (!bt_value_is_string(url_value)) {
1796                 BT_COMP_LOGE("First element of `%s` parameter is required to be a string value (URL)",
1797                         INPUTS_PARAM);
1798                 goto error;
1799         }
1800
1801         url = bt_value_string_get(url_value);
1802         lttng_live->params.url = g_string_new(url);
1803         if (!lttng_live->params.url) {
1804                 goto error;
1805         }
1806
1807         value = bt_value_map_borrow_entry_value_const(params,
1808                 SESS_NOT_FOUND_ACTION_PARAM);
1809         if (value) {
1810                 if (!bt_value_is_string(value)) {
1811                         BT_COMP_LOGE("`%s` parameter is required to be a string value",
1812                                 SESS_NOT_FOUND_ACTION_PARAM);
1813                         goto error;
1814                 }
1815
1816                 lttng_live->params.sess_not_found_act =
1817                         parse_session_not_found_action_param(value);
1818                 if (lttng_live->params.sess_not_found_act == SESSION_NOT_FOUND_ACTION_UNKNOWN) {
1819                         BT_COMP_LOGE("Unexpected value for `%s` parameter: "
1820                                 "value=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1821                                 bt_value_string_get(value));
1822                         goto error;
1823                 }
1824         } else {
1825                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1826                         "defaulting to `%s`.",
1827                         SESS_NOT_FOUND_ACTION_PARAM,
1828                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1829                 lttng_live->params.sess_not_found_act =
1830                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1831         }
1832
1833         goto end;
1834
1835 error:
1836         lttng_live_component_destroy_data(lttng_live);
1837         lttng_live = NULL;
1838 end:
1839         return lttng_live;
1840 }
1841
1842 BT_HIDDEN
1843 bt_component_class_init_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_init_method_status ret =
1851                 BT_COMPONENT_CLASS_INIT_METHOD_STATUS_OK;
1852         bt_self_component *self_comp =
1853                 bt_self_component_source_as_self_component(self_comp_src);
1854         bt_logging_level log_level = bt_component_get_logging_level(
1855                 bt_self_component_as_component(self_comp));
1856         bt_self_component_add_port_status add_port_status;
1857
1858         lttng_live = lttng_live_component_create(params, log_level, self_comp);
1859         if (!lttng_live) {
1860                 ret = BT_COMPONENT_CLASS_INIT_METHOD_STATUS_MEMORY_ERROR;
1861                 goto error;
1862         }
1863
1864         add_port_status = bt_self_component_source_add_output_port(
1865                 self_comp_src, "out", NULL, NULL);
1866         switch (add_port_status) {
1867         case BT_SELF_COMPONENT_ADD_PORT_STATUS_ERROR:
1868                 ret = BT_COMPONENT_CLASS_INIT_METHOD_STATUS_ERROR;
1869                 goto error;
1870         case BT_SELF_COMPONENT_ADD_PORT_STATUS_MEMORY_ERROR:
1871                 ret = BT_COMPONENT_CLASS_INIT_METHOD_STATUS_MEMORY_ERROR;
1872                 goto error;
1873         default:
1874                 break;
1875         }
1876
1877         bt_self_component_set_data(self_comp, lttng_live);
1878         goto end;
1879
1880 error:
1881         lttng_live_component_destroy_data(lttng_live);
1882         lttng_live = NULL;
1883 end:
1884         return ret;
1885 }