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         int ret = 0;
 441
 442         if (!session->attached) {
 443                 ret = lttng_live_attach_session(session);
 444                 if (ret) {
 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         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 460                 struct lttng_live_trace *trace =
 461                         g_ptr_array_index(session->traces, trace_idx);
 462
 463                 status = lttng_live_metadata_update(trace);
 464                 if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 465                                 status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 466                         goto end;
 467                 }
 468         }
 469         status = lttng_live_lazy_msg_init(session);
 470
 471 end:
 472         return status;
 473 }
 474
 475 BT_HIDDEN
 476 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 477 {
 478         uint64_t session_idx;
 479
 480         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 481                         session_idx++) {
 482                 struct lttng_live_session *session =
 483                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 484                 session->new_streams_needed = true;
 485         }
 486 }
 487
 488 static
 489 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 490 {
 491         uint64_t session_idx, trace_idx;
 492
 493         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 494                         session_idx++) {
 495                 struct lttng_live_session *session =
 496                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 497                 session->new_streams_needed = true;
 498                 for (trace_idx = 0; trace_idx < session->traces->len;
 499                                 trace_idx++) {
 500                         struct lttng_live_trace *trace =
 501                                 g_ptr_array_index(session->traces, trace_idx);
 502                         trace->new_metadata_needed = true;
 503                 }
 504         }
 505 }
 506
 507 static
 508 enum lttng_live_iterator_status
 509 lttng_live_iterator_handle_new_streams_and_metadata(
 510                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 511 {
 512         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 513         uint64_t session_idx = 0, nr_sessions_opened = 0;
 514         struct lttng_live_session *session;
 515         enum session_not_found_action sess_not_found_act =
 516                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 517
 518         /*
 519          * In a remotely distant future, we could add a "new
 520          * session" flag to the protocol, which would tell us that we
 521          * need to query for new sessions even though we have sessions
 522          * currently ongoing.
 523          */
 524         if (lttng_live_msg_iter->sessions->len == 0) {
 525                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 526                         ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 527                         goto end;
 528                 } else {
 529                         /*
 530                          * Retry to create a viewer session for the requested
 531                          * session name.
 532                          */
 533                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
 534                                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 535                                 goto end;
 536                         }
 537                 }
 538         }
 539
 540         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 541                         session_idx++) {
 542                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 543                                 session_idx);
 544                 ret = lttng_live_get_session(lttng_live_msg_iter, session);
 545                 switch (ret) {
 546                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 547                         break;
 548                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 549                         ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 550                         break;
 551                 default:
 552                         goto end;
 553                 }
 554                 if (!session->closed) {
 555                         nr_sessions_opened++;
 556                 }
 557         }
 558 end:
 559         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK &&
 560                         sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 561                         nr_sessions_opened == 0) {
 562                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 563         }
 564         return ret;
 565 }
 566
 567 static
 568 enum lttng_live_iterator_status emit_inactivity_message(
 569                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 570                 struct lttng_live_stream_iterator *stream_iter,
 571                 bt_message **message, uint64_t timestamp)
 572 {
 573         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 574         bt_message *msg = NULL;
 575
 576         BT_ASSERT(stream_iter->trace->clock_class);
 577
 578         msg = bt_message_message_iterator_inactivity_create(
 579                 lttng_live_msg_iter->self_msg_iter,
 580                 stream_iter->trace->clock_class, timestamp);
 581         if (!msg) {
 582                 goto error;
 583         }
 584
 585         *message = msg;
 586 end:
 587         return ret;
 588
 589 error:
 590         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 591         bt_message_put_ref(msg);
 592         goto end;
 593 }
 594
 595 static
 596 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 597                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 598                 struct lttng_live_stream_iterator *lttng_live_stream,
 599                 bt_message **message)
 600 {
 601         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 602
 603         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 604                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 605         }
 606
 607         if (lttng_live_stream->current_inactivity_ts ==
 608                         lttng_live_stream->last_inactivity_ts) {
 609                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 610                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 611                 goto end;
 612         }
 613
 614         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 615                 message, lttng_live_stream->current_inactivity_ts);
 616
 617         lttng_live_stream->last_inactivity_ts =
 618                 lttng_live_stream->current_inactivity_ts;
 619 end:
 620         return ret;
 621 }
 622
 623 static
 624 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 625                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 626                 const bt_message *msg, int64_t last_msg_ts_ns,
 627                 int64_t *ts_ns)
 628 {
 629         const bt_clock_class *clock_class = NULL;
 630         const bt_clock_snapshot *clock_snapshot = NULL;
 631         int ret = 0;
 632         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 633         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 634
 635         BT_ASSERT_DBG(msg);
 636         BT_ASSERT_DBG(ts_ns);
 637
 638         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 639                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 640                 last_msg_ts_ns);
 641
 642         switch (bt_message_get_type(msg)) {
 643         case BT_MESSAGE_TYPE_EVENT:
 644                 clock_class = bt_message_event_borrow_stream_class_default_clock_class_const(
 645                                 msg);
 646                 BT_ASSERT_DBG(clock_class);
 647
 648                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 649                         msg);
 650                 break;
 651         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 652                 clock_class = bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 653                         msg);
 654                 BT_ASSERT(clock_class);
 655
 656                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 657                         msg);
 658                 break;
 659         case BT_MESSAGE_TYPE_PACKET_END:
 660                 clock_class = bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 661                         msg);
 662                 BT_ASSERT(clock_class);
 663
 664                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 665                         msg);
 666                 break;
 667         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 668                 clock_class = bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 669                         msg);
 670                 BT_ASSERT(clock_class);
 671
 672                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 673                         msg);
 674                 break;
 675         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 676                 clock_class = bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 677                         msg);
 678                 BT_ASSERT(clock_class);
 679
 680                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 681                         msg);
 682                 break;
 683         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 684                 clock_snapshot = bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 685                         msg);
 686                 break;
 687         default:
 688                 /* All the other messages have a higher priority */
 689                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 690                 *ts_ns = last_msg_ts_ns;
 691                 goto end;
 692         }
 693
 694         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 695         BT_ASSERT_DBG(clock_class);
 696
 697         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 698         if (ret) {
 699                 BT_COMP_LOGE("Cannot get nanoseconds from Epoch of clock snapshot: "
 700                         "clock-snapshot-addr=%p", clock_snapshot);
 701                 goto error;
 702         }
 703
 704         goto end;
 705
 706 error:
 707         ret = -1;
 708
 709 end:
 710         if (ret == 0) {
 711                 BT_COMP_LOGD("Found message's timestamp: "
 712                         "iter-data-addr=%p, msg-addr=%p, "
 713                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 714                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 715         }
 716
 717         return ret;
 718 }
 719
 720 static
 721 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 722                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 723                 struct lttng_live_stream_iterator *lttng_live_stream,
 724                 bt_message **message)
 725 {
 726         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 727         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 728         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 729         enum bt_msg_iter_status status;
 730         uint64_t session_idx, trace_idx;
 731
 732         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 733                         session_idx++) {
 734                 struct lttng_live_session *session =
 735                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 736
 737                 if (session->new_streams_needed) {
 738                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 739                         goto end;
 740                 }
 741                 for (trace_idx = 0; trace_idx < session->traces->len;
 742                                 trace_idx++) {
 743                         struct lttng_live_trace *trace =
 744                                 g_ptr_array_index(session->traces, trace_idx);
 745                         if (trace->new_metadata_needed) {
 746                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 747                                 goto end;
 748                         }
 749                 }
 750         }
 751
 752         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 753                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 754                 goto end;
 755         }
 756
 757         status = bt_msg_iter_get_next_message(lttng_live_stream->msg_iter,
 758                 lttng_live_msg_iter->self_msg_iter, message);
 759         switch (status) {
 760         case BT_MSG_ITER_STATUS_EOF:
 761                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 762                 break;
 763         case BT_MSG_ITER_STATUS_OK:
 764                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 765                 break;
 766         case BT_MSG_ITER_STATUS_AGAIN:
 767                 /*
 768                  * Continue immediately (end of packet). The next
 769                  * get_index may return AGAIN to delay the following
 770                  * attempt.
 771                  */
 772                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 773                 break;
 774         case BT_MSG_ITER_STATUS_INVAL:
 775                 /* No argument provided by the user, so don't return INVAL. */
 776         case BT_MSG_ITER_STATUS_ERROR:
 777         default:
 778                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 779                 BT_COMP_LOGW("CTF msg iterator return an error or failed msg_iter=%p",
 780                         lttng_live_stream->msg_iter);
 781                 break;
 782         }
 783
 784 end:
 785         return ret;
 786 }
 787
 788 static
 789 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 790                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 791                 struct lttng_live_stream_iterator *stream_iter,
 792                 bt_message **curr_msg)
 793 {
 794         enum lttng_live_iterator_status live_status =
 795                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 796         /*
 797          * The viewer has hung up on us so we are closing the stream. The
 798          * `bt_msg_iter` should simply realize that it needs to close the
 799          * stream properly by emitting the necessary stream end message.
 800          */
 801         enum bt_msg_iter_status status = bt_msg_iter_get_next_message(
 802                 stream_iter->msg_iter, lttng_live_msg_iter->self_msg_iter,
 803                 curr_msg);
 804
 805         if (status == BT_MSG_ITER_STATUS_ERROR) {
 806                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 807                 goto end;
 808         }
 809
 810         BT_ASSERT(status == BT_MSG_ITER_STATUS_OK);
 811
 812 end:
 813         return live_status;
 814 }
 815
 816 /*
 817  * helper function:
 818  *            handle_no_data_streams()
 819  *              retry:
 820  *                - for each ACTIVE_NO_DATA stream:
 821  *                  - query relayd for stream data, or quiescence info.
 822  *                    - if need metadata, get metadata, goto retry.
 823  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 824  *                  - if quiescent, move to QUIESCENT streams
 825  *                  - if fetched data, move to ACTIVE_DATA streams
 826  *                (at this point each stream either has data, or is quiescent)
 827  *
 828  *
 829  * iterator_next:
 830  *            handle_new_streams_and_metadata()
 831  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 832  *                  - query relayd for metadata
 833  *
 834  *            call handle_active_no_data_streams()
 835  *
 836  *            handle_quiescent_streams()
 837  *                - if at least one stream is ACTIVE_DATA:
 838  *                  - peek stream event with lowest timestamp -> next_ts
 839  *                  - for each quiescent stream
 840  *                    - if next_ts >= quiescent end
 841  *                      - set state to ACTIVE_NO_DATA
 842  *                - else
 843  *                  - for each quiescent stream
 844  *                      - set state to ACTIVE_NO_DATA
 845  *
 846  *            call handle_active_no_data_streams()
 847  *
 848  *            handle_active_data_streams()
 849  *                - if at least one stream is ACTIVE_DATA:
 850  *                    - get stream event with lowest timestamp from heap
 851  *                    - make that stream event the current message.
 852  *                    - move this stream heap position to its next event
 853  *                      - if we need to fetch data from relayd, move
 854  *                        stream to ACTIVE_NO_DATA.
 855  *                    - return OK
 856  *                - return AGAIN
 857  *
 858  * end criterion: ctrl-c on client. If relayd exits or the session
 859  * closes on the relay daemon side, we keep on waiting for streams.
 860  * Eventually handle --end timestamp (also an end criterion).
 861  *
 862  * When disconnected from relayd: try to re-connect endlessly.
 863  */
 864 static
 865 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 866                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 867                 struct lttng_live_stream_iterator *stream_iter,
 868                 bt_message **curr_msg)
 869 {
 870         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 871         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 872         enum lttng_live_iterator_status live_status;
 873
 874         if (stream_iter->has_stream_hung_up) {
 875                 /*
 876                  * The stream has hung up and the stream was properly closed
 877                  * during the last call to the current function. Return _END
 878                  * status now so that this stream iterator is removed for the
 879                  * stream iterator list.
 880                  */
 881                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 882                 goto end;
 883         }
 884
 885 retry:
 886         print_stream_state(stream_iter);
 887         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 888                 lttng_live_msg_iter);
 889         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 890                 goto end;
 891         }
 892         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 893                 lttng_live_msg_iter, stream_iter);
 894
 895         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 896                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 897                         /*
 898                          * We overwrite `live_status` since `curr_msg` is
 899                          * likely set to a valid message in this function.
 900                          */
 901                         live_status = lttng_live_iterator_close_stream(
 902                                 lttng_live_msg_iter, stream_iter, curr_msg);
 903                 }
 904                 goto end;
 905         }
 906         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 907                 lttng_live_msg_iter, stream_iter, curr_msg);
 908         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 909                 BT_ASSERT(!*curr_msg);
 910                 goto end;
 911         }
 912         if (*curr_msg) {
 913                 goto end;
 914         }
 915         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 916                 lttng_live_msg_iter, stream_iter, curr_msg);
 917         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 918                 BT_ASSERT(!*curr_msg);
 919         }
 920
 921 end:
 922         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 923                 goto retry;
 924         }
 925
 926         return live_status;
 927 }
 928
 929 static
 930 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 931                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 932                 struct lttng_live_trace *live_trace,
 933                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 934 {
 935         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 936         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 937         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 938         enum lttng_live_iterator_status stream_iter_status;;
 939         int64_t youngest_candidate_msg_ts = INT64_MAX;
 940         uint64_t stream_iter_idx;
 941
 942         BT_ASSERT_DBG(live_trace);
 943         BT_ASSERT_DBG(live_trace->stream_iterators);
 944         /*
 945          * Update the current message of every stream iterators of this trace.
 946          * The current msg of every stream must have a timestamp equal or
 947          * larger than the last message returned by this iterator. We must
 948          * ensure monotonicity.
 949          */
 950         stream_iter_idx = 0;
 951         while (stream_iter_idx < live_trace->stream_iterators->len) {
 952                 bool stream_iter_is_ended = false;
 953                 struct lttng_live_stream_iterator *stream_iter =
 954                         g_ptr_array_index(live_trace->stream_iterators,
 955                                 stream_iter_idx);
 956
 957                 /*
 958                  * Find if there is are now current message for this stream
 959                  * iterator get it.
 960                  */
 961                 while (!stream_iter->current_msg) {
 962                         bt_message *msg = NULL;
 963                         int64_t curr_msg_ts_ns = INT64_MAX;
 964                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
 965                                 lttng_live_msg_iter, stream_iter, &msg);
 966
 967                         BT_COMP_LOGD("live stream iterator returned status :%s",
 968                                 print_live_iterator_status(stream_iter_status));
 969                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 970                                 stream_iter_is_ended = true;
 971                                 break;
 972                         }
 973
 974                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 975                                 goto end;
 976                         }
 977
 978                         BT_ASSERT_DBG(msg);
 979
 980                         /*
 981                          * Get the timestamp in nanoseconds from origin of this
 982                          * messsage.
 983                          */
 984                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
 985                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
 986                                 &curr_msg_ts_ns);
 987
 988                         /*
 989                          * Check if the message of the current live stream
 990                          * iterator occured at the exact same time or after the
 991                          * last message returned by this component's message
 992                          * iterator. If not, we return an error.
 993                          */
 994                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
 995                                 stream_iter->current_msg = msg;
 996                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
 997                         } else {
 998                                 /*
 999                                  * We received a message in the past. To ensure
1000                                  * monotonicity, we can't send it forward.
1001                                  */
1002                                 BT_COMP_LOGE("Message's timestamp is less than "
1003                                         "lttng-live's message iterator's last "
1004                                         "returned timestamp: "
1005                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1006                                         "last-msg-ts=%" PRId64,
1007                                         lttng_live_msg_iter, curr_msg_ts_ns,
1008                                         lttng_live_msg_iter->last_msg_ts_ns);
1009                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1010                                 goto end;
1011                         }
1012                 }
1013
1014                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1015
1016                 if (!stream_iter_is_ended) {
1017                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1018                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1019                                 /*
1020                                  * Update the current best candidate message
1021                                  * for the stream iterator of this live trace
1022                                  * to be forwarded downstream.
1023                                  */
1024                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1025                                 youngest_candidate_stream_iter = stream_iter;
1026                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1027                                 /*
1028                                  * Order the messages in an arbitrary but
1029                                  * deterministic way.
1030                                  */
1031                                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1032                                 int ret = common_muxing_compare_messages(
1033                                         stream_iter->current_msg,
1034                                         youngest_candidate_stream_iter->current_msg);
1035                                 if (ret < 0) {
1036                                         /*
1037                                          * The `youngest_candidate_stream_iter->current_msg`
1038                                          * should go first. Update the next
1039                                          * iterator and the current timestamp.
1040                                          */
1041                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1042                                         youngest_candidate_stream_iter = stream_iter;
1043                                 } else if (ret == 0) {
1044                                         /*
1045                                          * Unable to pick which one should go
1046                                          * first.
1047                                          */
1048                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1049                                                 "stream-iter-addr=%p"
1050                                                 "stream-iter-addr=%p",
1051                                                 stream_iter,
1052                                                 youngest_candidate_stream_iter);
1053                                 }
1054                         }
1055
1056                         stream_iter_idx++;
1057                 } else {
1058                         /*
1059                          * The live stream iterator has ended. That
1060                          * iterator is removed from the array, but
1061                          * there is no need to increment
1062                          * stream_iter_idx as
1063                          * g_ptr_array_remove_index_fast replaces the
1064                          * removed element with the array's last
1065                          * element.
1066                          */
1067                         g_ptr_array_remove_index_fast(
1068                                 live_trace->stream_iterators,
1069                                 stream_iter_idx);
1070                 }
1071         }
1072
1073         if (youngest_candidate_stream_iter) {
1074                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1075                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1076         } else {
1077                 /*
1078                  * The only case where we don't have a candidate for this trace
1079                  * is if we reached the end of all the iterators.
1080                  */
1081                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1082                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1083         }
1084
1085 end:
1086         return stream_iter_status;
1087 }
1088
1089 static
1090 enum lttng_live_iterator_status next_stream_iterator_for_session(
1091                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1092                 struct lttng_live_session *session,
1093                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1094 {
1095         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1096         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1097         enum lttng_live_iterator_status stream_iter_status;
1098         uint64_t trace_idx = 0;
1099         int64_t youngest_candidate_msg_ts = INT64_MAX;
1100         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1101
1102         /*
1103          * Make sure we are attached to the session and look for new streams
1104          * and metadata.
1105          */
1106         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1107         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1108                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1109                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1110                 goto end;
1111         }
1112
1113         BT_ASSERT_DBG(session->traces);
1114
1115         while (trace_idx < session->traces->len) {
1116                 bool trace_is_ended = false;
1117                 struct lttng_live_stream_iterator *stream_iter;
1118                 struct lttng_live_trace *trace =
1119                         g_ptr_array_index(session->traces, trace_idx);
1120
1121                 stream_iter_status = next_stream_iterator_for_trace(
1122                         lttng_live_msg_iter, trace, &stream_iter);
1123                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1124                         /*
1125                          * All the live stream iterators for this trace are
1126                          * ENDed. Remove the trace from this session.
1127                          */
1128                         trace_is_ended = true;
1129                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1130                         goto end;
1131                 }
1132
1133                 if (!trace_is_ended) {
1134                         BT_ASSERT_DBG(stream_iter);
1135
1136                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1137                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1138                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1139                                 youngest_candidate_stream_iter = stream_iter;
1140                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1141                                 /*
1142                                  * Order the messages in an arbitrary but
1143                                  * deterministic way.
1144                                  */
1145                                 int ret = common_muxing_compare_messages(
1146                                         stream_iter->current_msg,
1147                                         youngest_candidate_stream_iter->current_msg);
1148                                 if (ret < 0) {
1149                                         /*
1150                                          * The `youngest_candidate_stream_iter->current_msg`
1151                                          * should go first. Update the next iterator
1152                                          * and the current timestamp.
1153                                          */
1154                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1155                                         youngest_candidate_stream_iter = stream_iter;
1156                                 } else if (ret == 0) {
1157                                         /* Unable to pick which one should go first. */
1158                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1159                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1160                                                 stream_iter, youngest_candidate_stream_iter);
1161                                 }
1162                         }
1163                         trace_idx++;
1164                 } else {
1165                         /*
1166                          * trace_idx is not incremented since
1167                          * g_ptr_array_remove_index_fast replaces the
1168                          * element at trace_idx with the array's last element.
1169                          */
1170                         g_ptr_array_remove_index_fast(session->traces,
1171                                 trace_idx);
1172                 }
1173         }
1174         if (youngest_candidate_stream_iter) {
1175                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1176                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1177         } else {
1178                 /*
1179                  * The only cases where we don't have a candidate for this
1180                  * trace is:
1181                  *  1. if we reached the end of all the iterators of all the
1182                  *  traces of this session,
1183                  *  2. if we never had live stream iterator in the first place.
1184                  *
1185                  * In either cases, we return END.
1186                  */
1187                 BT_ASSERT(session->traces->len == 0);
1188                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1189         }
1190 end:
1191         return stream_iter_status;
1192 }
1193
1194 static inline
1195 void put_messages(bt_message_array_const msgs, uint64_t count)
1196 {
1197         uint64_t i;
1198
1199         for (i = 0; i < count; i++) {
1200                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1201         }
1202 }
1203
1204 BT_HIDDEN
1205 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1206                 bt_self_message_iterator *self_msg_it,
1207                 bt_message_array_const msgs, uint64_t capacity,
1208                 uint64_t *count)
1209 {
1210         bt_component_class_message_iterator_next_method_status status;
1211         struct lttng_live_msg_iter *lttng_live_msg_iter =
1212                 bt_self_message_iterator_get_data(self_msg_it);
1213         struct lttng_live_component *lttng_live =
1214                 lttng_live_msg_iter->lttng_live_comp;
1215         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1216         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1217         enum lttng_live_iterator_status stream_iter_status;
1218         uint64_t session_idx;
1219
1220         *count = 0;
1221
1222         BT_ASSERT_DBG(lttng_live_msg_iter);
1223
1224         /*
1225          * Clear all the invalid message reference that might be left over in
1226          * the output array.
1227          */
1228         memset(msgs, 0, capacity * sizeof(*msgs));
1229
1230         /*
1231          * If no session are exposed on the relay found at the url provided by
1232          * the user, session count will be 0. In this case, we return status
1233          * end to return gracefully.
1234          */
1235         if (lttng_live_msg_iter->sessions->len == 0) {
1236                 if (lttng_live->params.sess_not_found_act !=
1237                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1238                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1239                         goto no_session;
1240                 } else {
1241                         /*
1242                          * The are no more active session for this session
1243                          * name. Retry to create a viewer session for the
1244                          * requested session name.
1245                          */
1246                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1247                                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1248                                 goto no_session;
1249                         }
1250                 }
1251         }
1252
1253         if (lttng_live_msg_iter->active_stream_iter == 0) {
1254                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1255         }
1256
1257         /*
1258          * Here the muxing of message is done.
1259          *
1260          * We need to iterate over all the streams of all the traces of all the
1261          * viewer sessions in order to get the message with the smallest
1262          * timestamp. In this case, a session is a viewer session and there is
1263          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1264          * kernel). Each viewer session can have multiple traces, for example,
1265          * 64bit UST viewer sessions could have multiple per-pid traces.
1266          *
1267          * We iterate over the streams of each traces to update and see what is
1268          * their next message's timestamp. From those timestamps, we select the
1269          * message with the smallest timestamp as the best candidate message
1270          * for that trace and do the same thing across all the sessions.
1271          *
1272          * We then compare the timestamp of best candidate message of all the
1273          * sessions to pick the message with the smallest timestamp and we
1274          * return it.
1275          */
1276         while (*count < capacity) {
1277                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1278                           *candidate_stream_iter = NULL;
1279                 int64_t youngest_msg_ts_ns = INT64_MAX;
1280
1281                 BT_ASSERT_DBG(lttng_live_msg_iter->sessions);
1282                 session_idx = 0;
1283                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1284                         struct lttng_live_session *session =
1285                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1286                                         session_idx);
1287
1288                         /* Find the best candidate message to send downstream. */
1289                         stream_iter_status = next_stream_iterator_for_session(
1290                                 lttng_live_msg_iter, session,
1291                                 &candidate_stream_iter);
1292
1293                         /* If we receive an END status, it means that either:
1294                          * - Those traces never had active streams (UST with no
1295                          *   data produced yet),
1296                          * - All live stream iterators have ENDed.*/
1297                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1298                                 if (session->closed && session->traces->len == 0) {
1299                                         /*
1300                                          * Remove the session from the list.
1301                                          * session_idx is not modified since
1302                                          * g_ptr_array_remove_index_fast
1303                                          * replaces the the removed element with
1304                                          * the array's last element.
1305                                          */
1306                                         g_ptr_array_remove_index_fast(
1307                                                 lttng_live_msg_iter->sessions,
1308                                                 session_idx);
1309                                 } else {
1310                                         session_idx++;
1311                                 }
1312                                 continue;
1313                         }
1314
1315                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1316                                 goto end;
1317                         }
1318
1319                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1320                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1321                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1322                                 youngest_stream_iter = candidate_stream_iter;
1323                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1324                                 /*
1325                                  * The currently selected message to be sent
1326                                  * downstream next has the exact same timestamp
1327                                  * that of the current candidate message. We
1328                                  * must break the tie in a predictable manner.
1329                                  */
1330                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1331                                 /*
1332                                  * Order the messages in an arbitrary but
1333                                  * deterministic way.
1334                                  */
1335                                 int ret = common_muxing_compare_messages(
1336                                         candidate_stream_iter->current_msg,
1337                                         youngest_stream_iter->current_msg);
1338                                 if (ret < 0) {
1339                                         /*
1340                                          * The `candidate_stream_iter->current_msg`
1341                                          * should go first. Update the next
1342                                          * iterator and the current timestamp.
1343                                          */
1344                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1345                                         youngest_stream_iter = candidate_stream_iter;
1346                                 } else if (ret == 0) {
1347                                         /* Unable to pick which one should go first. */
1348                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1349                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1350                                                 youngest_stream_iter, candidate_stream_iter);
1351                                 }
1352                         }
1353
1354                         session_idx++;
1355                 }
1356
1357                 if (!youngest_stream_iter) {
1358                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1359                         goto end;
1360                 }
1361
1362                 BT_ASSERT_DBG(youngest_stream_iter->current_msg);
1363                 /* Ensure monotonicity. */
1364                 BT_ASSERT_DBG(lttng_live_msg_iter->last_msg_ts_ns <=
1365                         youngest_stream_iter->current_msg_ts_ns);
1366
1367                 /*
1368                  * Insert the next message to the message batch. This will set
1369                  * stream iterator current messsage to NULL so that next time
1370                  * we fetch the next message of that stream iterator
1371                  */
1372                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1373                 (*count)++;
1374
1375                 /* Update the last timestamp in nanoseconds sent downstream. */
1376                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1377                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1378
1379                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1380         }
1381 end:
1382         switch (stream_iter_status) {
1383         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1384         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1385                 if (*count > 0) {
1386                         /*
1387                          * We received a again status but we have some messages
1388                          * to send downstream. We send them and return OK for
1389                          * now. On the next call we return again if there are
1390                          * still no new message to send.
1391                          */
1392                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1393                 } else {
1394                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1395                 }
1396                 break;
1397         case LTTNG_LIVE_ITERATOR_STATUS_END:
1398                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1399                 break;
1400         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1401                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1402                 break;
1403         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1404         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1405         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1406                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1407                 /* Put all existing messages on error. */
1408                 put_messages(msgs, *count);
1409                 break;
1410         default:
1411                 abort();
1412         }
1413
1414 no_session:
1415         return status;
1416 }
1417
1418 BT_HIDDEN
1419 bt_component_class_message_iterator_initialize_method_status lttng_live_msg_iter_init(
1420                 bt_self_message_iterator *self_msg_it,
1421                 bt_self_message_iterator_configuration *config,
1422                 bt_self_component_source *self_comp_src,
1423                 bt_self_component_port_output *self_port)
1424 {
1425         bt_component_class_message_iterator_initialize_method_status ret =
1426                 BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_OK;
1427         bt_self_component *self_comp =
1428                 bt_self_component_source_as_self_component(self_comp_src);
1429         struct lttng_live_component *lttng_live;
1430         struct lttng_live_msg_iter *lttng_live_msg_iter;
1431         bt_logging_level log_level;
1432
1433         BT_ASSERT(self_msg_it);
1434
1435         lttng_live = bt_self_component_get_data(self_comp);
1436         log_level = lttng_live->log_level;
1437         self_comp = lttng_live->self_comp;
1438
1439         /* There can be only one downstream iterator at the same time. */
1440         BT_ASSERT(!lttng_live->has_msg_iter);
1441         lttng_live->has_msg_iter = true;
1442
1443         lttng_live_msg_iter = g_new0(struct lttng_live_msg_iter, 1);
1444         if (!lttng_live_msg_iter) {
1445                 ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1446                 goto end;
1447         }
1448
1449         lttng_live_msg_iter->log_level = lttng_live->log_level;
1450         lttng_live_msg_iter->self_comp = lttng_live->self_comp;
1451         lttng_live_msg_iter->lttng_live_comp = lttng_live;
1452         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1453
1454         lttng_live_msg_iter->active_stream_iter = 0;
1455         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1456         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1457                 (GDestroyNotify) lttng_live_destroy_session);
1458         BT_ASSERT(lttng_live_msg_iter->sessions);
1459
1460         lttng_live_msg_iter->viewer_connection =
1461                 live_viewer_connection_create(lttng_live->params.url->str, false,
1462                         lttng_live_msg_iter, log_level);
1463         if (!lttng_live_msg_iter->viewer_connection) {
1464                 goto error;
1465         }
1466
1467         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1468                 goto error;
1469         }
1470         if (lttng_live_msg_iter->sessions->len == 0) {
1471                 switch (lttng_live->params.sess_not_found_act) {
1472                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1473                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1474                                 "session. Keep trying to connect because of "
1475                                 "%s=\"%s\" component parameter: url=\"%s\"",
1476                                 SESS_NOT_FOUND_ACTION_PARAM,
1477                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1478                                 lttng_live->params.url->str);
1479                         break;
1480                 case SESSION_NOT_FOUND_ACTION_FAIL:
1481                         BT_COMP_LOGE("Unable to connect to the requested live viewer "
1482                                 "session. Fail the message iterator"
1483                                 "initialization because of %s=\"%s\" "
1484                                 "component parameter: url =\"%s\"",
1485                                 SESS_NOT_FOUND_ACTION_PARAM,
1486                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1487                                 lttng_live->params.url->str);
1488                         goto error;
1489                 case SESSION_NOT_FOUND_ACTION_END:
1490                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1491                                 "session. End gracefully at the first _next() "
1492                                 "call because of %s=\"%s\" component parameter: "
1493                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1494                                 SESS_NOT_FOUND_ACTION_END_STR,
1495                                 lttng_live->params.url->str);
1496                         break;
1497                 default:
1498                         abort();
1499                 }
1500         }
1501
1502         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1503
1504         goto end;
1505 error:
1506         ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1507         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1508 end:
1509         return ret;
1510 }
1511
1512 static struct bt_param_validation_map_value_entry_descr list_sessions_params[] = {
1513         { URL_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { .type = BT_VALUE_TYPE_STRING } },
1514         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1515 };
1516
1517 static
1518 bt_component_class_query_method_status lttng_live_query_list_sessions(
1519                 const bt_value *params, const bt_value **result,
1520                 bt_self_component_class *self_comp_class,
1521                 bt_logging_level log_level)
1522 {
1523         bt_component_class_query_method_status status;
1524         const bt_value *url_value = NULL;
1525         const char *url;
1526         struct live_viewer_connection *viewer_connection = NULL;
1527         enum bt_param_validation_status validation_status;
1528         gchar *validate_error = NULL;
1529
1530         validation_status = bt_param_validation_validate(params,
1531                 list_sessions_params, &validate_error);
1532         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1533                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1534                 goto error;
1535         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1536                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1537                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class, "%s", validate_error);
1538                 goto error;
1539         }
1540
1541         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1542         url = bt_value_string_get(url_value);
1543
1544         viewer_connection = live_viewer_connection_create(url, true, NULL,
1545                 log_level);
1546         if (!viewer_connection) {
1547                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1548                 goto error;
1549         }
1550
1551         status = live_viewer_connection_list_sessions(viewer_connection,
1552                 result);
1553         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1554                 goto error;
1555         }
1556
1557         goto end;
1558
1559 error:
1560         BT_VALUE_PUT_REF_AND_RESET(*result);
1561
1562         if (status >= 0) {
1563                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1564         }
1565
1566 end:
1567         if (viewer_connection) {
1568                 live_viewer_connection_destroy(viewer_connection);
1569         }
1570
1571         g_free(validate_error);
1572
1573         return status;
1574 }
1575
1576 static
1577 bt_component_class_query_method_status lttng_live_query_support_info(
1578                 const bt_value *params, const bt_value **result,
1579                 bt_logging_level log_level)
1580 {
1581         bt_component_class_query_method_status status =
1582                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1583         const bt_value *input_type_value;
1584         const bt_value *input_value;
1585         double weight = 0;
1586         struct bt_common_lttng_live_url_parts parts = { 0 };
1587
1588         /* Used by the logging macros */
1589         __attribute__((unused)) bt_self_component *self_comp = NULL;
1590
1591         *result = NULL;
1592         input_type_value = bt_value_map_borrow_entry_value_const(params,
1593                 "type");
1594         if (!input_type_value) {
1595                 BT_COMP_LOGE("Missing expected `type` parameter.");
1596                 goto error;
1597         }
1598
1599         if (!bt_value_is_string(input_type_value)) {
1600                 BT_COMP_LOGE("`type` parameter is not a string value.");
1601                 goto error;
1602         }
1603
1604         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1605                 /* We don't handle file system paths */
1606                 goto create_result;
1607         }
1608
1609         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1610         if (!input_value) {
1611                 BT_COMP_LOGE("Missing expected `input` parameter.");
1612                 goto error;
1613         }
1614
1615         if (!bt_value_is_string(input_value)) {
1616                 BT_COMP_LOGE("`input` parameter is not a string value.");
1617                 goto error;
1618         }
1619
1620         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1621                 NULL, 0);
1622         if (parts.session_name) {
1623                 /*
1624                  * Looks pretty much like an LTTng live URL: we got the
1625                  * session name part, which forms a complete URL.
1626                  */
1627                 weight = .75;
1628         }
1629
1630 create_result:
1631         *result = bt_value_real_create_init(weight);
1632         if (!*result) {
1633                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1634                 goto error;
1635         }
1636
1637         goto end;
1638
1639 error:
1640         if (status >= 0) {
1641                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1642         }
1643
1644         BT_ASSERT(!*result);
1645
1646 end:
1647         bt_common_destroy_lttng_live_url_parts(&parts);
1648         return status;
1649 }
1650
1651 BT_HIDDEN
1652 bt_component_class_query_method_status lttng_live_query(
1653                 bt_self_component_class_source *comp_class,
1654                 bt_private_query_executor *priv_query_exec,
1655                 const char *object, const bt_value *params,
1656                 __attribute__((unused)) void *method_data,
1657                 const bt_value **result)
1658 {
1659         bt_component_class_query_method_status status =
1660                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1661         bt_self_component *self_comp = NULL;
1662         bt_self_component_class *self_comp_class =
1663                 bt_self_component_class_source_as_self_component_class(comp_class);
1664         bt_logging_level log_level = bt_query_executor_get_logging_level(
1665                 bt_private_query_executor_as_query_executor_const(
1666                         priv_query_exec));
1667
1668         if (strcmp(object, "sessions") == 0) {
1669                 status = lttng_live_query_list_sessions(params, result,
1670                         self_comp_class, log_level);
1671         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1672                 status = lttng_live_query_support_info(params, result,
1673                         log_level);
1674         } else {
1675                 BT_COMP_LOGI("Unknown query object `%s`", object);
1676                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1677                 goto end;
1678         }
1679
1680 end:
1681         return status;
1682 }
1683
1684 static
1685 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1686 {
1687         if (!lttng_live) {
1688                 return;
1689         }
1690         if (lttng_live->params.url) {
1691                 g_string_free(lttng_live->params.url, TRUE);
1692         }
1693         g_free(lttng_live);
1694 }
1695
1696 BT_HIDDEN
1697 void lttng_live_component_finalize(bt_self_component_source *component)
1698 {
1699         void *data = bt_self_component_get_data(
1700                 bt_self_component_source_as_self_component(component));
1701
1702         if (!data) {
1703                 return;
1704         }
1705         lttng_live_component_destroy_data(data);
1706 }
1707
1708 static
1709 enum session_not_found_action parse_session_not_found_action_param(
1710         const bt_value *no_session_param)
1711 {
1712         enum session_not_found_action action;
1713         const char *no_session_act_str = bt_value_string_get(no_session_param);
1714
1715         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1716                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1717         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1718                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1719         } else {
1720                 BT_ASSERT(strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0);
1721                 action = SESSION_NOT_FOUND_ACTION_END;
1722         }
1723
1724         return action;
1725 }
1726
1727 static struct bt_param_validation_value_descr inputs_elem_descr = {
1728         .type = BT_VALUE_TYPE_STRING,
1729 };
1730
1731 static const char *sess_not_found_action_choices[] = {
1732         SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1733         SESS_NOT_FOUND_ACTION_FAIL_STR,
1734         SESS_NOT_FOUND_ACTION_END_STR,
1735 };
1736
1737 static struct bt_param_validation_map_value_entry_descr params_descr[] = {
1738         { INPUTS_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { BT_VALUE_TYPE_ARRAY, .array = {
1739                 .min_length = 1,
1740                 .max_length = 1,
1741                 .element_type = &inputs_elem_descr,
1742         } } },
1743         { SESS_NOT_FOUND_ACTION_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL, { BT_VALUE_TYPE_STRING, .string = {
1744                 .choices = sess_not_found_action_choices,
1745         } } },
1746         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1747 };
1748
1749 static
1750 bt_component_class_initialize_method_status lttng_live_component_create(
1751                 const bt_value *params,
1752                 bt_logging_level log_level,
1753                 bt_self_component *self_comp,
1754                 struct lttng_live_component **component)
1755 {
1756         struct lttng_live_component *lttng_live = NULL;
1757         const bt_value *inputs_value;
1758         const bt_value *url_value;
1759         const bt_value *value;
1760         const char *url;
1761         enum bt_param_validation_status validation_status;
1762         gchar *validation_error = NULL;
1763         bt_component_class_initialize_method_status status;
1764
1765         validation_status = bt_param_validation_validate(params, params_descr,
1766                 &validation_error);
1767         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1768                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1769                 goto error;
1770         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1771                 BT_COMP_LOGE_APPEND_CAUSE(self_comp, "%s", validation_error);
1772                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
1773                 goto error;
1774         }
1775
1776         lttng_live = g_new0(struct lttng_live_component, 1);
1777         if (!lttng_live) {
1778                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1779                 goto end;
1780         }
1781         lttng_live->log_level = log_level;
1782         lttng_live->self_comp = self_comp;
1783         lttng_live->max_query_size = MAX_QUERY_SIZE;
1784         lttng_live->has_msg_iter = false;
1785
1786         inputs_value =
1787                 bt_value_map_borrow_entry_value_const(params, INPUTS_PARAM);
1788         url_value =
1789                 bt_value_array_borrow_element_by_index_const(inputs_value, 0);
1790         url = bt_value_string_get(url_value);
1791
1792         lttng_live->params.url = g_string_new(url);
1793         if (!lttng_live->params.url) {
1794                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1795                 goto error;
1796         }
1797
1798         value = bt_value_map_borrow_entry_value_const(params,
1799                 SESS_NOT_FOUND_ACTION_PARAM);
1800         if (value) {
1801                 lttng_live->params.sess_not_found_act =
1802                         parse_session_not_found_action_param(value);
1803         } else {
1804                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1805                         "defaulting to `%s`.",
1806                         SESS_NOT_FOUND_ACTION_PARAM,
1807                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1808                 lttng_live->params.sess_not_found_act =
1809                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1810         }
1811
1812         status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;
1813         goto end;
1814
1815 error:
1816         lttng_live_component_destroy_data(lttng_live);
1817         lttng_live = NULL;
1818 end:
1819         g_free(validation_error);
1820
1821         *component = lttng_live;
1822         return status;
1823 }
1824
1825 BT_HIDDEN
1826 bt_component_class_initialize_method_status lttng_live_component_init(
1827                 bt_self_component_source *self_comp_src,
1828                 bt_self_component_source_configuration *config,
1829                 const bt_value *params,
1830                 __attribute__((unused)) void *init_method_data)
1831 {
1832         struct lttng_live_component *lttng_live;
1833         bt_component_class_initialize_method_status ret;
1834         bt_self_component *self_comp =
1835                 bt_self_component_source_as_self_component(self_comp_src);
1836         bt_logging_level log_level = bt_component_get_logging_level(
1837                 bt_self_component_as_component(self_comp));
1838         bt_self_component_add_port_status add_port_status;
1839
1840         ret = lttng_live_component_create(params, log_level, self_comp, &lttng_live);
1841         if (ret != BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK) {
1842                 goto error;
1843         }
1844
1845         add_port_status = bt_self_component_source_add_output_port(
1846                 self_comp_src, "out", NULL, NULL);
1847         if (add_port_status != BT_SELF_COMPONENT_ADD_PORT_STATUS_OK) {
1848                 ret = (int) add_port_status;
1849                 goto end;
1850         }
1851
1852         bt_self_component_set_data(self_comp, lttng_live);
1853         goto end;
1854
1855 error:
1856         lttng_live_component_destroy_data(lttng_live);
1857         lttng_live = NULL;
1858 end:
1859         return ret;
1860 }