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