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 (session->lttng_live_msg_iter &&
 278                                         !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 =
 382                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 383         struct packet_index index;
 384         enum lttng_live_stream_state orig_state = lttng_live_stream->state;
 385
 386         if (lttng_live_stream->trace->new_metadata_needed) {
 387                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 388                 goto end;
 389         }
 390         if (lttng_live_stream->trace->session->new_streams_needed) {
 391                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 392                 goto end;
 393         }
 394         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_NO_DATA &&
 395                         lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA) {
 396                 goto end;
 397         }
 398         ret = lttng_live_get_next_index(lttng_live_msg_iter, lttng_live_stream,
 399                 &index);
 400         if (ret != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 401                 goto end;
 402         }
 403         BT_ASSERT(lttng_live_stream->state != LTTNG_LIVE_STREAM_EOF);
 404         if (lttng_live_stream->state == LTTNG_LIVE_STREAM_QUIESCENT) {
 405                 uint64_t last_inact_ts = lttng_live_stream->last_inactivity_ts,
 406                          curr_inact_ts = lttng_live_stream->current_inactivity_ts;
 407
 408                 if (orig_state == LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA &&
 409                                 last_inact_ts == curr_inact_ts) {
 410                         ret = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 411                         print_stream_state(lttng_live_stream);
 412                 } else {
 413                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 414                 }
 415                 goto end;
 416         }
 417         lttng_live_stream->base_offset = index.offset;
 418         lttng_live_stream->offset = index.offset;
 419         lttng_live_stream->len = index.packet_size / CHAR_BIT;
 420 end:
 421         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK) {
 422                 ret = lttng_live_iterator_next_check_stream_state(lttng_live_stream);
 423         }
 424         return ret;
 425 }
 426
 427 /*
 428  * Creation of the message requires the ctf trace class to be created
 429  * beforehand, but the live protocol gives us all streams (including metadata)
 430  * at once. So we split it in three steps: getting streams, getting metadata
 431  * (which creates the ctf trace class), and then creating the per-stream
 432  * messages.
 433  */
 434 static
 435 enum lttng_live_iterator_status lttng_live_get_session(
 436                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 437                 struct lttng_live_session *session)
 438 {
 439         enum lttng_live_iterator_status status;
 440         uint64_t trace_idx;
 441         int ret = 0;
 442
 443         if (!session->attached) {
 444                 ret = lttng_live_attach_session(session);
 445                 if (ret) {
 446                         if (lttng_live_msg_iter && lttng_live_graph_is_canceled(
 447                                         lttng_live_msg_iter)) {
 448                                 status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 449                         } else {
 450                                 status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 451                         }
 452                         goto end;
 453                 }
 454         }
 455
 456         status = lttng_live_get_new_streams(session);
 457         if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 458                         status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 459                 goto end;
 460         }
 461         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 462                 struct lttng_live_trace *trace =
 463                         g_ptr_array_index(session->traces, trace_idx);
 464
 465                 status = lttng_live_metadata_update(trace);
 466                 if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 467                                 status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 468                         goto end;
 469                 }
 470         }
 471         status = lttng_live_lazy_msg_init(session);
 472
 473 end:
 474         return status;
 475 }
 476
 477 BT_HIDDEN
 478 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 479 {
 480         uint64_t session_idx;
 481
 482         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 483                         session_idx++) {
 484                 struct lttng_live_session *session =
 485                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 486                 session->new_streams_needed = true;
 487         }
 488 }
 489
 490 static
 491 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 492 {
 493         uint64_t session_idx, trace_idx;
 494
 495         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 496                         session_idx++) {
 497                 struct lttng_live_session *session =
 498                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 499                 session->new_streams_needed = true;
 500                 for (trace_idx = 0; trace_idx < session->traces->len;
 501                                 trace_idx++) {
 502                         struct lttng_live_trace *trace =
 503                                 g_ptr_array_index(session->traces, trace_idx);
 504                         trace->new_metadata_needed = true;
 505                 }
 506         }
 507 }
 508
 509 static
 510 enum lttng_live_iterator_status
 511 lttng_live_iterator_handle_new_streams_and_metadata(
 512                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 513 {
 514         enum lttng_live_iterator_status ret =
 515                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 516         uint64_t session_idx = 0, nr_sessions_opened = 0;
 517         struct lttng_live_session *session;
 518         enum session_not_found_action sess_not_found_act =
 519                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 520
 521         /*
 522          * In a remotely distant future, we could add a "new
 523          * session" flag to the protocol, which would tell us that we
 524          * need to query for new sessions even though we have sessions
 525          * currently ongoing.
 526          */
 527         if (lttng_live_msg_iter->sessions->len == 0) {
 528                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 529                         ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 530                         goto end;
 531                 } else {
 532                         /*
 533                          * Retry to create a viewer session for the requested
 534                          * session name.
 535                          */
 536                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
 537                                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 538                                 goto end;
 539                         }
 540                 }
 541         }
 542
 543         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 544                         session_idx++) {
 545                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 546                                 session_idx);
 547                 ret = lttng_live_get_session(lttng_live_msg_iter, session);
 548                 switch (ret) {
 549                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 550                         break;
 551                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 552                         ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 553                         break;
 554                 default:
 555                         goto end;
 556                 }
 557                 if (!session->closed) {
 558                         nr_sessions_opened++;
 559                 }
 560         }
 561 end:
 562         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK &&
 563                         sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 564                         nr_sessions_opened == 0) {
 565                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 566         }
 567         return ret;
 568 }
 569
 570 static
 571 enum lttng_live_iterator_status emit_inactivity_message(
 572                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 573                 struct lttng_live_stream_iterator *stream_iter,
 574                 bt_message **message, uint64_t timestamp)
 575 {
 576         enum lttng_live_iterator_status ret =
 577                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 578         bt_message *msg = NULL;
 579
 580         BT_ASSERT(stream_iter->trace->clock_class);
 581
 582         msg = bt_message_message_iterator_inactivity_create(
 583                         lttng_live_msg_iter->self_msg_iter,
 584                         stream_iter->trace->clock_class,
 585                         timestamp);
 586         if (!msg) {
 587                 goto error;
 588         }
 589
 590         *message = msg;
 591 end:
 592         return ret;
 593
 594 error:
 595         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 596         bt_message_put_ref(msg);
 597         goto end;
 598 }
 599
 600 static
 601 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 602                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 603                 struct lttng_live_stream_iterator *lttng_live_stream,
 604                 bt_message **message)
 605 {
 606         enum lttng_live_iterator_status ret =
 607                         LTTNG_LIVE_ITERATOR_STATUS_OK;
 608
 609         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 610                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 611         }
 612
 613         if (lttng_live_stream->current_inactivity_ts ==
 614                         lttng_live_stream->last_inactivity_ts) {
 615                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 616                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 617                 goto end;
 618         }
 619
 620         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 621                         message, lttng_live_stream->current_inactivity_ts);
 622
 623         lttng_live_stream->last_inactivity_ts =
 624                         lttng_live_stream->current_inactivity_ts;
 625 end:
 626         return ret;
 627 }
 628
 629 static
 630 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 631                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 632                 const bt_message *msg, int64_t last_msg_ts_ns,
 633                 int64_t *ts_ns)
 634 {
 635         const bt_clock_class *clock_class = NULL;
 636         const bt_clock_snapshot *clock_snapshot = NULL;
 637         int ret = 0;
 638         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 639         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 640
 641         BT_ASSERT(msg);
 642         BT_ASSERT(ts_ns);
 643
 644         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 645                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 646                 last_msg_ts_ns);
 647
 648         switch (bt_message_get_type(msg)) {
 649         case BT_MESSAGE_TYPE_EVENT:
 650                 clock_class =
 651                         bt_message_event_borrow_stream_class_default_clock_class_const(
 652                                 msg);
 653                 BT_ASSERT(clock_class);
 654
 655                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 656                         msg);
 657                 break;
 658         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 659                 clock_class =
 660                         bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 661                         msg);
 662                 BT_ASSERT(clock_class);
 663
 664                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 665                         msg);
 666                 break;
 667         case BT_MESSAGE_TYPE_PACKET_END:
 668                 clock_class =
 669                         bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 670                         msg);
 671                 BT_ASSERT(clock_class);
 672
 673                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 674                         msg);
 675                 break;
 676         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 677                 clock_class =
 678                         bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 679                         msg);
 680                 BT_ASSERT(clock_class);
 681
 682                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 683                         msg);
 684                 break;
 685         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 686                 clock_class =
 687                         bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 688                         msg);
 689                 BT_ASSERT(clock_class);
 690
 691                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 692                         msg);
 693                 break;
 694         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 695                 clock_snapshot =
 696                         bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 697                                 msg);
 698                 break;
 699         default:
 700                 /* All the other messages have a higher priority */
 701                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 702                 *ts_ns = last_msg_ts_ns;
 703                 goto end;
 704         }
 705
 706         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 707         BT_ASSERT(clock_class);
 708
 709         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 710         if (ret) {
 711                 BT_COMP_LOGE("Cannot get nanoseconds from Epoch of clock snapshot: "
 712                         "clock-snapshot-addr=%p", clock_snapshot);
 713                 goto error;
 714         }
 715
 716         goto end;
 717
 718 error:
 719         ret = -1;
 720
 721 end:
 722         if (ret == 0) {
 723                 BT_COMP_LOGD("Found message's timestamp: "
 724                         "iter-data-addr=%p, msg-addr=%p, "
 725                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 726                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 727         }
 728
 729         return ret;
 730 }
 731
 732 static
 733 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 734                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 735                 struct lttng_live_stream_iterator *lttng_live_stream,
 736                 bt_message **message)
 737 {
 738         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 739         enum bt_msg_iter_status status;
 740         uint64_t session_idx, trace_idx;
 741         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 742         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 743
 744         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 745                         session_idx++) {
 746                 struct lttng_live_session *session =
 747                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 748
 749                 if (session->new_streams_needed) {
 750                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 751                         goto end;
 752                 }
 753                 for (trace_idx = 0; trace_idx < session->traces->len;
 754                                 trace_idx++) {
 755                         struct lttng_live_trace *trace =
 756                                 g_ptr_array_index(session->traces, trace_idx);
 757                         if (trace->new_metadata_needed) {
 758                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 759                                 goto end;
 760                         }
 761                 }
 762         }
 763
 764         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 765                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 766                 goto end;
 767         }
 768
 769         status = bt_msg_iter_get_next_message(lttng_live_stream->msg_iter,
 770                 lttng_live_msg_iter->self_msg_iter, message);
 771         switch (status) {
 772         case BT_MSG_ITER_STATUS_EOF:
 773                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 774                 break;
 775         case BT_MSG_ITER_STATUS_OK:
 776                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 777                 break;
 778         case BT_MSG_ITER_STATUS_AGAIN:
 779                 /*
 780                  * Continue immediately (end of packet). The next
 781                  * get_index may return AGAIN to delay the following
 782                  * attempt.
 783                  */
 784                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 785                 break;
 786         case BT_MSG_ITER_STATUS_INVAL:
 787                 /* No argument provided by the user, so don't return INVAL. */
 788         case BT_MSG_ITER_STATUS_ERROR:
 789         default:
 790                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 791                 BT_COMP_LOGW("CTF msg iterator return an error or failed msg_iter=%p",
 792                         lttng_live_stream->msg_iter);
 793                 break;
 794         }
 795
 796 end:
 797         return ret;
 798 }
 799
 800 static
 801 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 802                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 803                 struct lttng_live_stream_iterator *stream_iter,
 804                 bt_message **curr_msg)
 805 {
 806         enum lttng_live_iterator_status live_status =
 807                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 808         /*
 809          * The viewer has hung up on us so we are closing the stream. The
 810          * `bt_msg_iter` should simply realize that it needs to close the
 811          * stream properly by emitting the necessary stream end message.
 812          */
 813         enum bt_msg_iter_status status =
 814                 bt_msg_iter_get_next_message(stream_iter->msg_iter,
 815                         lttng_live_msg_iter->self_msg_iter, curr_msg);
 816
 817         if (status == BT_MSG_ITER_STATUS_ERROR) {
 818                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 819                 goto end;
 820         }
 821
 822         BT_ASSERT(status == BT_MSG_ITER_STATUS_OK);
 823
 824 end:
 825         return live_status;
 826 }
 827
 828 /*
 829  * helper function:
 830  *            handle_no_data_streams()
 831  *              retry:
 832  *                - for each ACTIVE_NO_DATA stream:
 833  *                  - query relayd for stream data, or quiescence info.
 834  *                    - if need metadata, get metadata, goto retry.
 835  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 836  *                  - if quiescent, move to QUIESCENT streams
 837  *                  - if fetched data, move to ACTIVE_DATA streams
 838  *                (at this point each stream either has data, or is quiescent)
 839  *
 840  *
 841  * iterator_next:
 842  *            handle_new_streams_and_metadata()
 843  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 844  *                  - query relayd for metadata
 845  *
 846  *            call handle_active_no_data_streams()
 847  *
 848  *            handle_quiescent_streams()
 849  *                - if at least one stream is ACTIVE_DATA:
 850  *                  - peek stream event with lowest timestamp -> next_ts
 851  *                  - for each quiescent stream
 852  *                    - if next_ts >= quiescent end
 853  *                      - set state to ACTIVE_NO_DATA
 854  *                - else
 855  *                  - for each quiescent stream
 856  *                      - set state to ACTIVE_NO_DATA
 857  *
 858  *            call handle_active_no_data_streams()
 859  *
 860  *            handle_active_data_streams()
 861  *                - if at least one stream is ACTIVE_DATA:
 862  *                    - get stream event with lowest timestamp from heap
 863  *                    - make that stream event the current message.
 864  *                    - move this stream heap position to its next event
 865  *                      - if we need to fetch data from relayd, move
 866  *                        stream to ACTIVE_NO_DATA.
 867  *                    - return OK
 868  *                - return AGAIN
 869  *
 870  * end criterion: ctrl-c on client. If relayd exits or the session
 871  * closes on the relay daemon side, we keep on waiting for streams.
 872  * Eventually handle --end timestamp (also an end criterion).
 873  *
 874  * When disconnected from relayd: try to re-connect endlessly.
 875  */
 876 static
 877 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 878                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 879                 struct lttng_live_stream_iterator *stream_iter,
 880                 bt_message **curr_msg)
 881 {
 882         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 883         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 884         enum lttng_live_iterator_status live_status;
 885
 886         if (stream_iter->has_stream_hung_up) {
 887                 /*
 888                  * The stream has hung up and the stream was properly closed
 889                  * during the last call to the current function. Return _END
 890                  * status now so that this stream iterator is removed for the
 891                  * stream iterator list.
 892                  */
 893                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 894                 goto end;
 895         }
 896
 897 retry:
 898         print_stream_state(stream_iter);
 899         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 900                         lttng_live_msg_iter);
 901         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 902                 goto end;
 903         }
 904         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 905                         lttng_live_msg_iter, stream_iter);
 906
 907         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 908                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 909                         /*
 910                          * We overwrite `live_status` since `curr_msg` is
 911                          * likely set to a valid message in this function.
 912                          */
 913                         live_status = lttng_live_iterator_close_stream(
 914                                 lttng_live_msg_iter, stream_iter, curr_msg);
 915                 }
 916                 goto end;
 917         }
 918         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 919                         lttng_live_msg_iter, stream_iter, curr_msg);
 920         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 921                 BT_ASSERT(!*curr_msg);
 922                 goto end;
 923         }
 924         if (*curr_msg) {
 925                 goto end;
 926         }
 927         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 928                         lttng_live_msg_iter, stream_iter, curr_msg);
 929         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 930                 BT_ASSERT(!*curr_msg);
 931         }
 932
 933 end:
 934         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 935                 goto retry;
 936         }
 937
 938         return live_status;
 939 }
 940
 941 static
 942 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 943                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 944                 struct lttng_live_trace *live_trace,
 945                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 946 {
 947         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 948         enum lttng_live_iterator_status stream_iter_status;;
 949         int64_t youngest_candidate_msg_ts = INT64_MAX;
 950         uint64_t stream_iter_idx;
 951         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 952         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 953
 954         BT_ASSERT(live_trace);
 955         BT_ASSERT(live_trace->stream_iterators);
 956         /*
 957          * Update the current message of every stream iterators of this trace.
 958          * The current msg of every stream must have a timestamp equal or
 959          * larger than the last message returned by this iterator. We must
 960          * ensure monotonicity.
 961          */
 962         stream_iter_idx = 0;
 963         while (stream_iter_idx < live_trace->stream_iterators->len) {
 964                 bool stream_iter_is_ended = false;
 965                 struct lttng_live_stream_iterator *stream_iter =
 966                         g_ptr_array_index(live_trace->stream_iterators,
 967                                         stream_iter_idx);
 968
 969                 /*
 970                  * Since we may remove elements from the GPtrArray as we
 971                  * iterate over it, it's possible to see the same element more
 972                  * than once.
 973                  */
 974                 if (stream_iter == youngest_candidate_stream_iter) {
 975                         stream_iter_idx++;
 976                         continue;
 977                 }
 978
 979                 /*
 980                  * Find if there is are now current message for this stream
 981                  * iterator get it.
 982                  */
 983                 while (!stream_iter->current_msg) {
 984                         bt_message *msg = NULL;
 985                         int64_t curr_msg_ts_ns = INT64_MAX;
 986                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
 987                                         lttng_live_msg_iter, stream_iter, &msg);
 988
 989                         BT_COMP_LOGD("live stream iterator returned status :%s",
 990                                         print_live_iterator_status(stream_iter_status));
 991                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 992                                 stream_iter_is_ended = true;
 993                                 break;
 994                         }
 995
 996                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 997                                 goto end;
 998                         }
 999
1000                         BT_ASSERT(msg);
1001
1002                         /*
1003                          * Get the timestamp in nanoseconds from origin of this
1004                          * messsage.
1005                          */
1006                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
1007                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
1008                                 &curr_msg_ts_ns);
1009
1010                         /*
1011                          * Check if the message of the current live stream
1012                          * iterator occured at the exact same time or after the
1013                          * last message returned by this component's message
1014                          * iterator. If not, we return an error.
1015                          */
1016                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
1017                                 stream_iter->current_msg = msg;
1018                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
1019                         } else {
1020                                 /*
1021                                  * We received a message in the past. To ensure
1022                                  * monotonicity, we can't send it forward.
1023                                  */
1024                                 BT_COMP_LOGE("Message's timestamp is less than "
1025                                         "lttng-live's message iterator's last "
1026                                         "returned timestamp: "
1027                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1028                                         "last-msg-ts=%" PRId64,
1029                                         lttng_live_msg_iter, curr_msg_ts_ns,
1030                                         lttng_live_msg_iter->last_msg_ts_ns);
1031                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1032                                 goto end;
1033                         }
1034                 }
1035
1036                 BT_ASSERT(stream_iter != youngest_candidate_stream_iter);
1037
1038                 if (!stream_iter_is_ended) {
1039                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1040                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1041                                 /*
1042                                  * Update the current best candidate message
1043                                  * for the stream iterator of this live trace
1044                                  * to be forwarded downstream.
1045                                  */
1046                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1047                                 youngest_candidate_stream_iter = stream_iter;
1048                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1049                                 /*
1050                                  * Order the messages in an arbitrary but
1051                                  * deterministic way.
1052                                  */
1053                                 BT_ASSERT(stream_iter != youngest_candidate_stream_iter);
1054                                 int ret = common_muxing_compare_messages(
1055                                         stream_iter->current_msg,
1056                                         youngest_candidate_stream_iter->current_msg);
1057                                 if (ret < 0) {
1058                                         /*
1059                                          * The `youngest_candidate_stream_iter->current_msg`
1060                                          * should go first. Update the next
1061                                          * iterator and the current timestamp.
1062                                          */
1063                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1064                                         youngest_candidate_stream_iter = stream_iter;
1065                                 } else if (ret == 0) {
1066                                         /*
1067                                          * Unable to pick which one should go
1068                                          * first.
1069                                          */
1070                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1071                                                 "stream-iter-addr=%p"
1072                                                 "stream-iter-addr=%p",
1073                                                 stream_iter,
1074                                                 youngest_candidate_stream_iter);
1075                                 }
1076                         }
1077
1078                         stream_iter_idx++;
1079                 } else {
1080                         /*
1081                          * The live stream iterator is ENDed. We remove that
1082                          * iterator from the list and we restart the iteration
1083                          * at the beginning of the live stream iterator array
1084                          * to because the removal will shuffle the array.
1085                          */
1086                         g_ptr_array_remove_index_fast(live_trace->stream_iterators,
1087                                 stream_iter_idx);
1088                         stream_iter_idx = 0;
1089                 }
1090         }
1091
1092         if (youngest_candidate_stream_iter) {
1093                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1094                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1095         } else {
1096                 /*
1097                  * The only case where we don't have a candidate for this trace
1098                  * is if we reached the end of all the iterators.
1099                  */
1100                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1101                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1102         }
1103
1104 end:
1105         return stream_iter_status;
1106 }
1107
1108 static
1109 enum lttng_live_iterator_status next_stream_iterator_for_session(
1110                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1111                 struct lttng_live_session *session,
1112                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1113 {
1114         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1115         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1116         enum lttng_live_iterator_status stream_iter_status;
1117         uint64_t trace_idx = 0;
1118         int64_t youngest_candidate_msg_ts = INT64_MAX;
1119         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1120
1121         /*
1122          * Make sure we are attached to the session and look for new streams
1123          * and metadata.
1124          */
1125         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1126         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1127                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1128                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1129                 goto end;
1130         }
1131
1132         BT_ASSERT(session->traces);
1133
1134         /*
1135          * Use while loops here rather then for loops so we can restart the
1136          * iteration if an element is removed from the array during the
1137          * looping.
1138          */
1139         while (trace_idx < session->traces->len) {
1140                 bool trace_is_ended = false;
1141                 struct lttng_live_stream_iterator *stream_iter;
1142                 struct lttng_live_trace *trace =
1143                         g_ptr_array_index(session->traces, trace_idx);
1144
1145                 stream_iter_status = next_stream_iterator_for_trace(
1146                         lttng_live_msg_iter, trace, &stream_iter);
1147                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1148                         /*
1149                          * All the live stream iterators for this trace are
1150                          * ENDed. Remove the trace from this session.
1151                          */
1152                         trace_is_ended = true;
1153                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1154                         goto end;
1155                 }
1156
1157                 if (!trace_is_ended) {
1158                         BT_ASSERT(stream_iter);
1159
1160                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1161                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1162                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1163                                 youngest_candidate_stream_iter = stream_iter;
1164                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1165                                 /*
1166                                  * Order the messages in an arbitrary but
1167                                  * deterministic way.
1168                                  */
1169                                 int ret = common_muxing_compare_messages(
1170                                         stream_iter->current_msg,
1171                                         youngest_candidate_stream_iter->current_msg);
1172                                 if (ret < 0) {
1173                                         /*
1174                                          * The `youngest_candidate_stream_iter->current_msg`
1175                                          * should go first. Update the next iterator
1176                                          * and the current timestamp.
1177                                          */
1178                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1179                                         youngest_candidate_stream_iter = stream_iter;
1180                                 } else if (ret == 0) {
1181                                         /* Unable to pick which one should go first. */
1182                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1183                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1184                                                 stream_iter, youngest_candidate_stream_iter);
1185                                 }
1186                         }
1187                         trace_idx++;
1188                 } else {
1189                         g_ptr_array_remove_index_fast(session->traces, trace_idx);
1190                         trace_idx = 0;
1191                 }
1192         }
1193         if (youngest_candidate_stream_iter) {
1194                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1195                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1196         } else {
1197                 /*
1198                  * The only cases where we don't have a candidate for this
1199                  * trace is:
1200                  *  1. if we reached the end of all the iterators of all the
1201                  *  traces of this session,
1202                  *  2. if we never had live stream iterator in the first place.
1203                  *
1204                  * In either cases, we return END.
1205                  */
1206                 BT_ASSERT(session->traces->len == 0);
1207                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1208         }
1209 end:
1210         return stream_iter_status;
1211 }
1212
1213 static inline
1214 void put_messages(bt_message_array_const msgs, uint64_t count)
1215 {
1216         uint64_t i;
1217
1218         for (i = 0; i < count; i++) {
1219                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1220         }
1221 }
1222
1223 BT_HIDDEN
1224 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1225                 bt_self_message_iterator *self_msg_it,
1226                 bt_message_array_const msgs, uint64_t capacity,
1227                 uint64_t *count)
1228 {
1229         bt_component_class_message_iterator_next_method_status status;
1230         struct lttng_live_msg_iter *lttng_live_msg_iter =
1231                 bt_self_message_iterator_get_data(self_msg_it);
1232         struct lttng_live_component *lttng_live =
1233                 lttng_live_msg_iter->lttng_live_comp;
1234         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1235         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1236         enum lttng_live_iterator_status stream_iter_status;
1237         uint64_t session_idx;
1238
1239         *count = 0;
1240
1241         BT_ASSERT(lttng_live_msg_iter);
1242
1243         /*
1244          * Clear all the invalid message reference that might be left over in
1245          * the output array.
1246          */
1247         memset(msgs, 0, capacity * sizeof(*msgs));
1248
1249         /*
1250          * If no session are exposed on the relay found at the url provided by
1251          * the user, session count will be 0. In this case, we return status
1252          * end to return gracefully.
1253          */
1254         if (lttng_live_msg_iter->sessions->len == 0) {
1255                 if (lttng_live->params.sess_not_found_act !=
1256                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1257                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1258                         goto no_session;
1259                 } else {
1260                         /*
1261                          * The are no more active session for this session
1262                          * name. Retry to create a viewer session for the
1263                          * requested session name.
1264                          */
1265                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1266                                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1267                                 goto no_session;
1268                         }
1269                 }
1270         }
1271
1272         if (lttng_live_msg_iter->active_stream_iter == 0) {
1273                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1274         }
1275
1276         /*
1277          * Here the muxing of message is done.
1278          *
1279          * We need to iterate over all the streams of all the traces of all the
1280          * viewer sessions in order to get the message with the smallest
1281          * timestamp. In this case, a session is a viewer session and there is
1282          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1283          * kernel). Each viewer session can have multiple traces, for example,
1284          * 64bit UST viewer sessions could have multiple per-pid traces.
1285          *
1286          * We iterate over the streams of each traces to update and see what is
1287          * their next message's timestamp. From those timestamps, we select the
1288          * message with the smallest timestamp as the best candidate message
1289          * for that trace and do the same thing across all the sessions.
1290          *
1291          * We then compare the timestamp of best candidate message of all the
1292          * sessions to pick the message with the smallest timestamp and we
1293          * return it.
1294          */
1295         while (*count < capacity) {
1296                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1297                           *candidate_stream_iter = NULL;
1298                 int64_t youngest_msg_ts_ns = INT64_MAX;
1299
1300                 BT_ASSERT(lttng_live_msg_iter->sessions);
1301                 session_idx = 0;
1302                 /*
1303                  * Use a while loop instead of a for loop so we can restart the
1304                  * iteration if we remove an element. We can safely call
1305                  * next_stream_iterator_for_session() multiple times on the
1306                  * same session as we only fetch a new message if there is no
1307                  * current next message for each live stream iterator.
1308                  * If all live stream iterator of that session already have a
1309                  * current next message, the function will simply exit return
1310                  * the same candidate live stream iterator every time.
1311                  */
1312                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1313                         struct lttng_live_session *session =
1314                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1315                                         session_idx);
1316
1317                         /* Find the best candidate message to send downstream. */
1318                         stream_iter_status = next_stream_iterator_for_session(
1319                                 lttng_live_msg_iter, session,
1320                                 &candidate_stream_iter);
1321
1322                         /* If we receive an END status, it means that either:
1323                          * - Those traces never had active streams (UST with no
1324                          *   data produced yet),
1325                          * - All live stream iterators have ENDed.*/
1326                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1327                                 if (session->closed && session->traces->len == 0) {
1328                                         /*
1329                                          * Remove the session from the list and restart the
1330                                          * iteration at the beginning of the array since the
1331                                          * removal shuffle the elements of the array.
1332                                          */
1333                                         g_ptr_array_remove_index_fast(
1334                                                 lttng_live_msg_iter->sessions,
1335                                                 session_idx);
1336                                         session_idx = 0;
1337                                 } else {
1338                                         session_idx++;
1339                                 }
1340                                 continue;
1341                         }
1342
1343                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1344                                 goto end;
1345                         }
1346
1347                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1348                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1349                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1350                                 youngest_stream_iter = candidate_stream_iter;
1351                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1352                                 /*
1353                                  * The currently selected message to be sent
1354                                  * downstream next has the exact same timestamp
1355                                  * that of the current candidate message. We
1356                                  * must break the tie in a predictable manner.
1357                                  */
1358                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1359                                 /*
1360                                  * Order the messages in an arbitrary but
1361                                  * deterministic way.
1362                                  */
1363                                 int ret = common_muxing_compare_messages(
1364                                         candidate_stream_iter->current_msg,
1365                                         youngest_stream_iter->current_msg);
1366                                 if (ret < 0) {
1367                                         /*
1368                                          * The `candidate_stream_iter->current_msg`
1369                                          * should go first. Update the next
1370                                          * iterator and the current timestamp.
1371                                          */
1372                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1373                                         youngest_stream_iter = candidate_stream_iter;
1374                                 } else if (ret == 0) {
1375                                         /* Unable to pick which one should go first. */
1376                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1377                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1378                                                 youngest_stream_iter, candidate_stream_iter);
1379                                 }
1380                         }
1381
1382                         session_idx++;
1383                 }
1384
1385                 if (!youngest_stream_iter) {
1386                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1387                         goto end;
1388                 }
1389
1390                 BT_ASSERT(youngest_stream_iter->current_msg);
1391                 /* Ensure monotonicity. */
1392                 BT_ASSERT(lttng_live_msg_iter->last_msg_ts_ns <=
1393                         youngest_stream_iter->current_msg_ts_ns);
1394
1395                 /*
1396                  * Insert the next message to the message batch. This will set
1397                  * stream iterator current messsage to NULL so that next time
1398                  * we fetch the next message of that stream iterator
1399                  */
1400                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1401                 (*count)++;
1402
1403                 /* Update the last timestamp in nanoseconds sent downstream. */
1404                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1405                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1406
1407                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1408         }
1409 end:
1410         switch (stream_iter_status) {
1411         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1412         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1413                 if (*count > 0) {
1414                         /*
1415                          * We received a again status but we have some messages
1416                          * to send downstream. We send them and return OK for
1417                          * now. On the next call we return again if there are
1418                          * still no new message to send.
1419                          */
1420                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1421                 } else {
1422                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1423                 }
1424                 break;
1425         case LTTNG_LIVE_ITERATOR_STATUS_END:
1426                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1427                 break;
1428         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1429                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1430                 break;
1431         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1432         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1433         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1434                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1435                 /* Put all existing messages on error. */
1436                 put_messages(msgs, *count);
1437                 break;
1438         default:
1439                 abort();
1440         }
1441
1442 no_session:
1443         return status;
1444 }
1445
1446 BT_HIDDEN
1447 bt_component_class_message_iterator_initialize_method_status lttng_live_msg_iter_init(
1448                 bt_self_message_iterator *self_msg_it,
1449                 bt_self_message_iterator_configuration *config,
1450                 bt_self_component_source *self_comp_src,
1451                 bt_self_component_port_output *self_port)
1452 {
1453         bt_component_class_message_iterator_initialize_method_status ret =
1454                 BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_OK;
1455         bt_self_component *self_comp =
1456                 bt_self_component_source_as_self_component(self_comp_src);
1457         struct lttng_live_component *lttng_live;
1458         struct lttng_live_msg_iter *lttng_live_msg_iter;
1459         bt_logging_level log_level;
1460
1461         BT_ASSERT(self_msg_it);
1462
1463         lttng_live = bt_self_component_get_data(self_comp);
1464         log_level = lttng_live->log_level;
1465         self_comp = lttng_live->self_comp;
1466
1467         /* There can be only one downstream iterator at the same time. */
1468         BT_ASSERT(!lttng_live->has_msg_iter);
1469         lttng_live->has_msg_iter = true;
1470
1471         lttng_live_msg_iter = g_new0(struct lttng_live_msg_iter, 1);
1472         if (!lttng_live_msg_iter) {
1473                 ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1474                 goto end;
1475         }
1476
1477         lttng_live_msg_iter->log_level = lttng_live->log_level;
1478         lttng_live_msg_iter->self_comp = lttng_live->self_comp;
1479         lttng_live_msg_iter->lttng_live_comp = lttng_live;
1480         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1481
1482         lttng_live_msg_iter->active_stream_iter = 0;
1483         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1484         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1485                 (GDestroyNotify) lttng_live_destroy_session);
1486         BT_ASSERT(lttng_live_msg_iter->sessions);
1487
1488         lttng_live_msg_iter->viewer_connection =
1489                 live_viewer_connection_create(lttng_live->params.url->str, false,
1490                         lttng_live_msg_iter, log_level);
1491         if (!lttng_live_msg_iter->viewer_connection) {
1492                 goto error;
1493         }
1494
1495         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1496                 goto error;
1497         }
1498         if (lttng_live_msg_iter->sessions->len == 0) {
1499                 switch (lttng_live->params.sess_not_found_act) {
1500                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1501                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1502                                 "session. Keep trying to connect because of "
1503                                 "%s=\"%s\" component parameter: url=\"%s\"",
1504                                 SESS_NOT_FOUND_ACTION_PARAM,
1505                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1506                                 lttng_live->params.url->str);
1507                         break;
1508                 case SESSION_NOT_FOUND_ACTION_FAIL:
1509                         BT_COMP_LOGE("Unable to connect to the requested live viewer "
1510                                 "session. Fail the message iterator"
1511                                 "initialization because of %s=\"%s\" "
1512                                 "component parameter: url =\"%s\"",
1513                                 SESS_NOT_FOUND_ACTION_PARAM,
1514                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1515                                 lttng_live->params.url->str);
1516                         goto error;
1517                 case SESSION_NOT_FOUND_ACTION_END:
1518                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1519                                 "session. End gracefully at the first _next() "
1520                                 "call because of %s=\"%s\" component parameter: "
1521                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1522                                 SESS_NOT_FOUND_ACTION_END_STR,
1523                                 lttng_live->params.url->str);
1524                         break;
1525                 default:
1526                         abort();
1527                 }
1528         }
1529
1530         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1531
1532         goto end;
1533 error:
1534         ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1535         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1536 end:
1537         return ret;
1538 }
1539
1540 static struct bt_param_validation_map_value_entry_descr list_sessions_params[] = {
1541         { URL_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { .type = BT_VALUE_TYPE_STRING } },
1542         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1543 };
1544
1545 static
1546 bt_component_class_query_method_status lttng_live_query_list_sessions(
1547                 const bt_value *params, const bt_value **result,
1548                 bt_self_component_class *self_comp_class,
1549                 bt_logging_level log_level)
1550 {
1551         bt_component_class_query_method_status status;
1552         const bt_value *url_value = NULL;
1553         const char *url;
1554         struct live_viewer_connection *viewer_connection = NULL;
1555         enum bt_param_validation_status validation_status;
1556         gchar *validate_error = NULL;
1557
1558         validation_status = bt_param_validation_validate(params,
1559                 list_sessions_params, &validate_error);
1560         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1561                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1562                 goto error;
1563         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1564                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1565                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class, "%s", validate_error);
1566                 goto error;
1567         }
1568
1569         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1570         url = bt_value_string_get(url_value);
1571
1572         viewer_connection = live_viewer_connection_create(url, true, NULL,
1573                 log_level);
1574         if (!viewer_connection) {
1575                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1576                 goto error;
1577         }
1578
1579         status = live_viewer_connection_list_sessions(viewer_connection,
1580                 result);
1581         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1582                 goto error;
1583         }
1584
1585         goto end;
1586
1587 error:
1588         BT_VALUE_PUT_REF_AND_RESET(*result);
1589
1590         if (status >= 0) {
1591                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1592         }
1593
1594 end:
1595         if (viewer_connection) {
1596                 live_viewer_connection_destroy(viewer_connection);
1597         }
1598
1599         g_free(validate_error);
1600
1601         return status;
1602 }
1603
1604 static
1605 bt_component_class_query_method_status lttng_live_query_support_info(
1606                 const bt_value *params, const bt_value **result,
1607                 bt_logging_level log_level)
1608 {
1609         bt_component_class_query_method_status status =
1610                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1611         const bt_value *input_type_value;
1612         const bt_value *input_value;
1613         double weight = 0;
1614         struct bt_common_lttng_live_url_parts parts = { 0 };
1615
1616         /* Used by the logging macros */
1617         __attribute__((unused)) bt_self_component *self_comp = NULL;
1618
1619         *result = NULL;
1620         input_type_value = bt_value_map_borrow_entry_value_const(params,
1621                 "type");
1622         if (!input_type_value) {
1623                 BT_COMP_LOGE("Missing expected `type` parameter.");
1624                 goto error;
1625         }
1626
1627         if (!bt_value_is_string(input_type_value)) {
1628                 BT_COMP_LOGE("`type` parameter is not a string value.");
1629                 goto error;
1630         }
1631
1632         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1633                 /* We don't handle file system paths */
1634                 goto create_result;
1635         }
1636
1637         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1638         if (!input_value) {
1639                 BT_COMP_LOGE("Missing expected `input` parameter.");
1640                 goto error;
1641         }
1642
1643         if (!bt_value_is_string(input_value)) {
1644                 BT_COMP_LOGE("`input` parameter is not a string value.");
1645                 goto error;
1646         }
1647
1648         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1649                 NULL, 0);
1650         if (parts.session_name) {
1651                 /*
1652                  * Looks pretty much like an LTTng live URL: we got the
1653                  * session name part, which forms a complete URL.
1654                  */
1655                 weight = .75;
1656         }
1657
1658 create_result:
1659         *result = bt_value_real_create_init(weight);
1660         if (!*result) {
1661                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1662                 goto error;
1663         }
1664
1665         goto end;
1666
1667 error:
1668         if (status >= 0) {
1669                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1670         }
1671
1672         BT_ASSERT(!*result);
1673
1674 end:
1675         bt_common_destroy_lttng_live_url_parts(&parts);
1676         return status;
1677 }
1678
1679 BT_HIDDEN
1680 bt_component_class_query_method_status lttng_live_query(
1681                 bt_self_component_class_source *comp_class,
1682                 bt_private_query_executor *priv_query_exec,
1683                 const char *object, const bt_value *params,
1684                 __attribute__((unused)) void *method_data,
1685                 const bt_value **result)
1686 {
1687         bt_component_class_query_method_status status =
1688                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1689         bt_self_component *self_comp = NULL;
1690         bt_self_component_class *self_comp_class =
1691                 bt_self_component_class_source_as_self_component_class(comp_class);
1692         bt_logging_level log_level = bt_query_executor_get_logging_level(
1693                 bt_private_query_executor_as_query_executor_const(
1694                         priv_query_exec));
1695
1696         if (strcmp(object, "sessions") == 0) {
1697                 status = lttng_live_query_list_sessions(params, result,
1698                         self_comp_class, log_level);
1699         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1700                 status = lttng_live_query_support_info(params, result,
1701                         log_level);
1702         } else {
1703                 BT_COMP_LOGI("Unknown query object `%s`", object);
1704                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1705                 goto end;
1706         }
1707
1708 end:
1709         return status;
1710 }
1711
1712 static
1713 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1714 {
1715         if (!lttng_live) {
1716                 return;
1717         }
1718         if (lttng_live->params.url) {
1719                 g_string_free(lttng_live->params.url, TRUE);
1720         }
1721         g_free(lttng_live);
1722 }
1723
1724 BT_HIDDEN
1725 void lttng_live_component_finalize(bt_self_component_source *component)
1726 {
1727         void *data = bt_self_component_get_data(
1728                         bt_self_component_source_as_self_component(component));
1729
1730         if (!data) {
1731                 return;
1732         }
1733         lttng_live_component_destroy_data(data);
1734 }
1735
1736 static
1737 enum session_not_found_action parse_session_not_found_action_param(
1738         const bt_value *no_session_param)
1739 {
1740         enum session_not_found_action action;
1741         const char *no_session_act_str = bt_value_string_get(no_session_param);
1742
1743         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1744                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1745         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1746                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1747         } else {
1748                 BT_ASSERT(strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0);
1749                 action = SESSION_NOT_FOUND_ACTION_END;
1750         }
1751
1752         return action;
1753 }
1754
1755 static struct bt_param_validation_value_descr inputs_elem_descr = {
1756         .type = BT_VALUE_TYPE_STRING,
1757 };
1758
1759 static const char *sess_not_found_action_choices[] = {
1760         SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1761         SESS_NOT_FOUND_ACTION_FAIL_STR,
1762         SESS_NOT_FOUND_ACTION_END_STR,
1763 };
1764
1765 static struct bt_param_validation_map_value_entry_descr params_descr[] = {
1766         { INPUTS_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { BT_VALUE_TYPE_ARRAY, .array = {
1767                 .min_length = 1,
1768                 .max_length = 1,
1769                 .element_type = &inputs_elem_descr,
1770         } } },
1771         { SESS_NOT_FOUND_ACTION_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL, { BT_VALUE_TYPE_STRING, .string = {
1772                 .choices = sess_not_found_action_choices,
1773         } } },
1774         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1775 };
1776
1777 static
1778 bt_component_class_initialize_method_status lttng_live_component_create(
1779                 const bt_value *params,
1780                 bt_logging_level log_level,
1781                 bt_self_component *self_comp,
1782                 struct lttng_live_component **component)
1783 {
1784         struct lttng_live_component *lttng_live = NULL;
1785         const bt_value *inputs_value;
1786         const bt_value *url_value;
1787         const bt_value *value;
1788         const char *url;
1789         enum bt_param_validation_status validation_status;
1790         gchar *validation_error = NULL;
1791         bt_component_class_initialize_method_status status;
1792
1793         validation_status = bt_param_validation_validate(params, params_descr,
1794                 &validation_error);
1795         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1796                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1797                 goto error;
1798         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1799                 BT_COMP_LOGE_APPEND_CAUSE(self_comp, "%s", validation_error);
1800                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
1801                 goto error;
1802         }
1803
1804         lttng_live = g_new0(struct lttng_live_component, 1);
1805         if (!lttng_live) {
1806                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1807                 goto end;
1808         }
1809         lttng_live->log_level = log_level;
1810         lttng_live->self_comp = self_comp;
1811         lttng_live->max_query_size = MAX_QUERY_SIZE;
1812         lttng_live->has_msg_iter = false;
1813
1814         inputs_value =
1815                 bt_value_map_borrow_entry_value_const(params, INPUTS_PARAM);
1816         url_value =
1817                 bt_value_array_borrow_element_by_index_const(inputs_value, 0);
1818         url = bt_value_string_get(url_value);
1819
1820         lttng_live->params.url = g_string_new(url);
1821         if (!lttng_live->params.url) {
1822                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1823                 goto error;
1824         }
1825
1826         value = bt_value_map_borrow_entry_value_const(params,
1827                 SESS_NOT_FOUND_ACTION_PARAM);
1828         if (value) {
1829                 lttng_live->params.sess_not_found_act =
1830                         parse_session_not_found_action_param(value);
1831         } else {
1832                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1833                         "defaulting to `%s`.",
1834                         SESS_NOT_FOUND_ACTION_PARAM,
1835                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1836                 lttng_live->params.sess_not_found_act =
1837                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1838         }
1839
1840         status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;
1841         goto end;
1842
1843 error:
1844         lttng_live_component_destroy_data(lttng_live);
1845         lttng_live = NULL;
1846 end:
1847         g_free(validation_error);
1848
1849         *component = lttng_live;
1850         return status;
1851 }
1852
1853 BT_HIDDEN
1854 bt_component_class_initialize_method_status lttng_live_component_init(
1855                 bt_self_component_source *self_comp_src,
1856                 bt_self_component_source_configuration *config,
1857                 const bt_value *params,
1858                 __attribute__((unused)) void *init_method_data)
1859 {
1860         struct lttng_live_component *lttng_live;
1861         bt_component_class_initialize_method_status ret;
1862         bt_self_component *self_comp =
1863                 bt_self_component_source_as_self_component(self_comp_src);
1864         bt_logging_level log_level = bt_component_get_logging_level(
1865                 bt_self_component_as_component(self_comp));
1866         bt_self_component_add_port_status add_port_status;
1867
1868         ret = lttng_live_component_create(params, log_level, self_comp, &lttng_live);
1869         if (ret != BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK) {
1870                 goto error;
1871         }
1872
1873         add_port_status = bt_self_component_source_add_output_port(
1874                 self_comp_src, "out", NULL, NULL);
1875         if (add_port_status != BT_SELF_COMPONENT_ADD_PORT_STATUS_OK) {
1876                 ret = (int) add_port_status;
1877                 goto end;
1878         }
1879
1880         bt_self_component_set_data(self_comp, lttng_live);
1881         goto end;
1882
1883 error:
1884         lttng_live_component_destroy_data(lttng_live);
1885         lttng_live = NULL;
1886 end:
1887         return ret;
1888 }