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