src/plugins/ctf/lttng-live/lttng-live.c

   1 /*
   2  * lttng-live.c
   3  *
   4  * Babeltrace CTF LTTng-live Client Component
   5  *
   6  * Copyright 2019 Francis Deslauriers <francis.deslauriers@efficios.com>
   7  * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8  * Copyright 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a copy
  13  * of this software and associated documentation files (the "Software"), to deal
  14  * in the Software without restriction, including without limitation the rights
  15  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  16  * copies of the Software, and to permit persons to whom the Software is
  17  * furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included in
  20  * all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  27  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  28  * SOFTWARE.
  29  */
  30
  31 #define BT_COMP_LOG_SELF_COMP self_comp
  32 #define BT_LOG_OUTPUT_LEVEL log_level
  33 #define BT_LOG_TAG "PLUGIN/SRC.CTF.LTTNG-LIVE"
  34 #include "logging/comp-logging.h"
  35
  36 #include <glib.h>
  37 #include <inttypes.h>
  38 #include <stdbool.h>
  39 #include <unistd.h>
  40
  41 #include "common/assert.h"
  42 #include <babeltrace2/babeltrace.h>
  43 #include "compat/compiler.h"
  44 #include <babeltrace2/types.h>
  45
  46 #include "plugins/common/muxing/muxing.h"
  47 #include "plugins/common/param-validation/param-validation.h"
  48
  49 #include "data-stream.h"
  50 #include "metadata.h"
  51 #include "lttng-live.h"
  52
  53 #define MAX_QUERY_SIZE                      (256*1024)
  54 #define URL_PARAM                           "url"
  55 #define INPUTS_PARAM                        "inputs"
  56 #define SESS_NOT_FOUND_ACTION_PARAM         "session-not-found-action"
  57 #define SESS_NOT_FOUND_ACTION_CONTINUE_STR  "continue"
  58 #define SESS_NOT_FOUND_ACTION_FAIL_STR      "fail"
  59 #define SESS_NOT_FOUND_ACTION_END_STR       "end"
  60
  61 #define print_dbg(fmt, ...)     BT_COMP_LOGD(fmt, ## __VA_ARGS__)
  62
  63 static
  64 const char *print_live_iterator_status(enum lttng_live_iterator_status status)
  65 {
  66         switch (status) {
  67         case LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
  68                 return "LTTNG_LIVE_ITERATOR_STATUS_CONTINUE";
  69         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
  70                 return "LTTNG_LIVE_ITERATOR_STATUS_AGAIN";
  71         case LTTNG_LIVE_ITERATOR_STATUS_END:
  72                 return "LTTNG_LIVE_ITERATOR_STATUS_END";
  73         case LTTNG_LIVE_ITERATOR_STATUS_OK:
  74                 return "LTTNG_LIVE_ITERATOR_STATUS_OK";
  75         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
  76                 return "LTTNG_LIVE_ITERATOR_STATUS_INVAL";
  77         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
  78                 return "LTTNG_LIVE_ITERATOR_STATUS_ERROR";
  79         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
  80                 return "LTTNG_LIVE_ITERATOR_STATUS_NOMEM";
  81         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
  82                 return "LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED";
  83         default:
  84                 abort();
  85         }
  86 }
  87
  88 static
  89 const char *print_state(struct lttng_live_stream_iterator *s)
  90 {
  91         switch (s->state) {
  92         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
  93                 return "ACTIVE_NO_DATA";
  94         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
  95                 return "QUIESCENT_NO_DATA";
  96         case LTTNG_LIVE_STREAM_QUIESCENT:
  97                 return "QUIESCENT";
  98         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
  99                 return "ACTIVE_DATA";
 100         case LTTNG_LIVE_STREAM_EOF:
 101                 return "EOF";
 102         default:
 103                 return "ERROR";
 104         }
 105 }
 106
 107 #define print_stream_state(live_stream_iter) \
 108         do { \
 109                 BT_COMP_LOGD("stream state %s last_inact_ts %" PRId64  \
 110                         ", curr_inact_ts %" PRId64, \
 111                         print_state(live_stream_iter), \
 112                         live_stream_iter->last_inactivity_ts, \
 113                         live_stream_iter->current_inactivity_ts); \
 114         } while (0);
 115
 116 BT_HIDDEN
 117 bool lttng_live_graph_is_canceled(struct lttng_live_msg_iter *msg_iter)
 118 {
 119         bool ret;
 120
 121         if (!msg_iter) {
 122                 ret = false;
 123                 goto end;
 124         }
 125
 126         ret = bt_self_message_iterator_is_interrupted(
 127                 msg_iter->self_msg_iter);
 128
 129 end:
 130         return ret;
 131 }
 132
 133 static
 134 struct lttng_live_trace *lttng_live_find_trace(struct lttng_live_session *session,
 135                 uint64_t trace_id)
 136 {
 137         uint64_t trace_idx;
 138         struct lttng_live_trace *ret_trace = NULL;
 139
 140         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 141                 struct lttng_live_trace *trace =
 142                         g_ptr_array_index(session->traces, trace_idx);
 143                 if (trace->id == trace_id) {
 144                         ret_trace = trace;
 145                         goto end;
 146                 }
 147         }
 148
 149 end:
 150         return ret_trace;
 151 }
 152
 153 static
 154 void lttng_live_destroy_trace(struct lttng_live_trace *trace)
 155 {
 156         bt_logging_level log_level = trace->log_level;
 157         bt_self_component *self_comp = trace->self_comp;
 158
 159         BT_COMP_LOGD("Destroy lttng_live_trace");
 160
 161         BT_ASSERT(trace->stream_iterators);
 162         g_ptr_array_free(trace->stream_iterators, TRUE);
 163
 164         BT_TRACE_PUT_REF_AND_RESET(trace->trace);
 165         BT_TRACE_CLASS_PUT_REF_AND_RESET(trace->trace_class);
 166
 167         lttng_live_metadata_fini(trace);
 168         g_free(trace);
 169 }
 170
 171 static
 172 struct lttng_live_trace *lttng_live_create_trace(struct lttng_live_session *session,
 173                 uint64_t trace_id)
 174 {
 175         struct lttng_live_trace *trace = NULL;
 176         bt_logging_level log_level = session->log_level;
 177         bt_self_component *self_comp = session->self_comp;
 178
 179         trace = g_new0(struct lttng_live_trace, 1);
 180         if (!trace) {
 181                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 182                         "Failed to allocate live trace");
 183                 goto error;
 184         }
 185         trace->log_level = session->log_level;
 186         trace->self_comp = session->self_comp;
 187         trace->session = session;
 188         trace->id = trace_id;
 189         trace->trace_class = NULL;
 190         trace->trace = NULL;
 191         trace->stream_iterators = g_ptr_array_new_with_free_func(
 192                 (GDestroyNotify) lttng_live_stream_iterator_destroy);
 193         BT_ASSERT(trace->stream_iterators);
 194         trace->new_metadata_needed = true;
 195         g_ptr_array_add(session->traces, trace);
 196
 197         BT_COMP_LOGI("Create trace");
 198         goto end;
 199 error:
 200         g_free(trace);
 201         trace = NULL;
 202 end:
 203         return trace;
 204 }
 205
 206 BT_HIDDEN
 207 struct lttng_live_trace *lttng_live_borrow_trace(
 208                 struct lttng_live_session *session, uint64_t trace_id)
 209 {
 210         struct lttng_live_trace *trace;
 211
 212         trace = lttng_live_find_trace(session, trace_id);
 213         if (trace) {
 214                 goto end;
 215         }
 216
 217         /* The session is the owner of the newly created trace. */
 218         trace = lttng_live_create_trace(session, trace_id);
 219
 220 end:
 221         return trace;
 222 }
 223
 224 BT_HIDDEN
 225 int lttng_live_add_session(struct lttng_live_msg_iter *lttng_live_msg_iter,
 226                 uint64_t session_id, const char *hostname,
 227                 const char *session_name)
 228 {
 229         int ret = 0;
 230         struct lttng_live_session *session;
 231         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 232         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 233
 234         session = g_new0(struct lttng_live_session, 1);
 235         if (!session) {
 236                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 237                         "Failed to allocate live session");
 238                 goto error;
 239         }
 240
 241         session->log_level = lttng_live_msg_iter->log_level;
 242         session->self_comp = lttng_live_msg_iter->self_comp;
 243         session->id = session_id;
 244         session->traces = g_ptr_array_new_with_free_func(
 245                 (GDestroyNotify) lttng_live_destroy_trace);
 246         BT_ASSERT(session->traces);
 247         session->lttng_live_msg_iter = lttng_live_msg_iter;
 248         session->new_streams_needed = true;
 249         session->hostname = g_string_new(hostname);
 250         BT_ASSERT(session->hostname);
 251
 252         session->session_name = g_string_new(session_name);
 253         BT_ASSERT(session->session_name);
 254
 255         BT_COMP_LOGI("Reading from session: %" PRIu64 " hostname: %s session_name: %s",
 256                 session->id, hostname, session_name);
 257         g_ptr_array_add(lttng_live_msg_iter->sessions, session);
 258         goto end;
 259 error:
 260         BT_COMP_LOGE_APPEND_CAUSE(self_comp, "Error adding session");
 261         g_free(session);
 262         ret = -1;
 263 end:
 264         return ret;
 265 }
 266
 267 static
 268 void lttng_live_destroy_session(struct lttng_live_session *session)
 269 {
 270         bt_logging_level log_level;
 271         bt_self_component *self_comp;
 272
 273         if (!session) {
 274                 goto end;
 275         }
 276
 277         log_level = session->log_level;
 278         self_comp = session->self_comp;
 279         BT_COMP_LOGD("Destroy lttng live session");
 280         if (session->id != -1ULL) {
 281                 if (lttng_live_detach_session(session)) {
 282                         if (!lttng_live_graph_is_canceled(
 283                                         session->lttng_live_msg_iter)) {
 284                                 /* Old relayd cannot detach sessions. */
 285                                 BT_COMP_LOGD("Unable to detach lttng live session %" PRIu64,
 286                                         session->id);
 287                         }
 288                 }
 289                 session->id = -1ULL;
 290         }
 291
 292         if (session->traces) {
 293                 g_ptr_array_free(session->traces, TRUE);
 294         }
 295
 296         if (session->hostname) {
 297                 g_string_free(session->hostname, TRUE);
 298         }
 299         if (session->session_name) {
 300                 g_string_free(session->session_name, TRUE);
 301         }
 302         g_free(session);
 303
 304 end:
 305         return;
 306 }
 307
 308 static
 309 void lttng_live_msg_iter_destroy(struct lttng_live_msg_iter *lttng_live_msg_iter)
 310 {
 311         if (!lttng_live_msg_iter) {
 312                 goto end;
 313         }
 314
 315         if (lttng_live_msg_iter->sessions) {
 316                 g_ptr_array_free(lttng_live_msg_iter->sessions, TRUE);
 317         }
 318
 319         BT_OBJECT_PUT_REF_AND_RESET(lttng_live_msg_iter->viewer_connection);
 320         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp);
 321         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp->has_msg_iter);
 322
 323         /* All stream iterators must be destroyed at this point. */
 324         BT_ASSERT(lttng_live_msg_iter->active_stream_iter == 0);
 325         lttng_live_msg_iter->lttng_live_comp->has_msg_iter = false;
 326
 327         g_free(lttng_live_msg_iter);
 328
 329 end:
 330         return;
 331 }
 332
 333 BT_HIDDEN
 334 void lttng_live_msg_iter_finalize(bt_self_message_iterator *self_msg_iter)
 335 {
 336         struct lttng_live_msg_iter *lttng_live_msg_iter;
 337
 338         BT_ASSERT(self_msg_iter);
 339
 340         lttng_live_msg_iter = bt_self_message_iterator_get_data(self_msg_iter);
 341         BT_ASSERT(lttng_live_msg_iter);
 342         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
 343 }
 344
 345 static
 346 enum lttng_live_iterator_status lttng_live_iterator_next_check_stream_state(
 347                 struct lttng_live_stream_iterator *lttng_live_stream)
 348 {
 349         bt_logging_level log_level = lttng_live_stream->log_level;
 350         bt_self_component *self_comp = lttng_live_stream->self_comp;
 351
 352         switch (lttng_live_stream->state) {
 353         case LTTNG_LIVE_STREAM_QUIESCENT:
 354         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
 355                 break;
 356         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
 357                 /* Invalid state. */
 358                 BT_COMP_LOGF("Unexpected stream state \"ACTIVE_NO_DATA\"");
 359                 abort();
 360         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
 361                 /* Invalid state. */
 362                 BT_COMP_LOGF("Unexpected stream state \"QUIESCENT_NO_DATA\"");
 363                 abort();
 364         case LTTNG_LIVE_STREAM_EOF:
 365                 break;
 366         }
 367         return LTTNG_LIVE_ITERATOR_STATUS_OK;
 368 }
 369
 370 /*
 371  * For active no data stream, fetch next data. It can be either:
 372  * - quiescent: need to put it in the prio heap at quiescent end
 373  *   timestamp,
 374  * - have data: need to wire up first event into the prio heap,
 375  * - have no data on this stream at this point: need to retry (AGAIN) or
 376  *   return EOF.
 377  */
 378 static
 379 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_no_data_stream(
 380                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 381                 struct lttng_live_stream_iterator *lttng_live_stream)
 382 {
 383         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 384         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 385         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 386         enum lttng_live_stream_state orig_state = lttng_live_stream->state;
 387         struct packet_index index;
 388
 389         if (lttng_live_stream->trace->new_metadata_needed) {
 390                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 391                 goto end;
 392         }
 393         if (lttng_live_stream->trace->session->new_streams_needed) {
 394                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 395                 goto end;
 396         }
 397         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_NO_DATA &&
 398                         lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA) {
 399                 goto end;
 400         }
 401         ret = lttng_live_get_next_index(lttng_live_msg_iter, lttng_live_stream,
 402                 &index);
 403         if (ret != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 404                 goto end;
 405         }
 406         BT_ASSERT_DBG(lttng_live_stream->state != LTTNG_LIVE_STREAM_EOF);
 407         if (lttng_live_stream->state == LTTNG_LIVE_STREAM_QUIESCENT) {
 408                 uint64_t last_inact_ts = lttng_live_stream->last_inactivity_ts,
 409                          curr_inact_ts = lttng_live_stream->current_inactivity_ts;
 410
 411                 if (orig_state == LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA &&
 412                                 last_inact_ts == curr_inact_ts) {
 413                         ret = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 414                         print_stream_state(lttng_live_stream);
 415                 } else {
 416                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 417                 }
 418                 goto end;
 419         }
 420         lttng_live_stream->base_offset = index.offset;
 421         lttng_live_stream->offset = index.offset;
 422         lttng_live_stream->len = index.packet_size / CHAR_BIT;
 423 end:
 424         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK) {
 425                 ret = lttng_live_iterator_next_check_stream_state(lttng_live_stream);
 426         }
 427         return ret;
 428 }
 429
 430 /*
 431  * Creation of the message requires the ctf trace class to be created
 432  * beforehand, but the live protocol gives us all streams (including metadata)
 433  * at once. So we split it in three steps: getting streams, getting metadata
 434  * (which creates the ctf trace class), and then creating the per-stream
 435  * messages.
 436  */
 437 static
 438 enum lttng_live_iterator_status lttng_live_get_session(
 439                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 440                 struct lttng_live_session *session)
 441 {
 442         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 443         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 444         enum lttng_live_iterator_status status;
 445         uint64_t trace_idx;
 446
 447         if (!session->attached) {
 448                 enum lttng_live_attach_session_status attach_status =
 449                         lttng_live_attach_session(session);
 450                 if (attach_status != LTTNG_LIVE_ATTACH_SESSION_STATUS_OK) {
 451                         if (lttng_live_graph_is_canceled(lttng_live_msg_iter)) {
 452                                 /*
 453                                  * Clear any causes appended in
 454                                  * `lttng_live_attach_session()` as we want to
 455                                  * return gracefully since the graph was
 456                                  * cancelled.
 457                                  */
 458                                 bt_current_thread_clear_error();
 459                                 status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 460                         } else {
 461                                 status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 462                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 463                                         "Error attaching to LTTng live session");
 464                         }
 465                         goto end;
 466                 }
 467         }
 468
 469         status = lttng_live_get_new_streams(session);
 470         if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 471                         status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 472                 goto end;
 473         }
 474         trace_idx = 0;
 475         while (trace_idx < session->traces->len) {
 476                 struct lttng_live_trace *trace =
 477                         g_ptr_array_index(session->traces, trace_idx);
 478
 479                 status = lttng_live_metadata_update(trace);
 480                 switch (status) {
 481                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 482                         trace_idx++;
 483                         break;
 484                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 485                         /*
 486                          * The trace has ended. Remove it of the array an
 487                          * continue the iteration.
 488                          * We can remove the trace safely when using the
 489                          * g_ptr_array_remove_index_fast because it replaces
 490                          * the element at trace_idx with the array's last
 491                          * element. trace_idx is not incremented because of
 492                          * that.
 493                          */
 494                         (void) g_ptr_array_remove_index_fast(session->traces,
 495                                 trace_idx);
 496                         break;
 497                 default:
 498                         goto end;
 499                 }
 500         }
 501         status = lttng_live_lazy_msg_init(session);
 502
 503 end:
 504         return status;
 505 }
 506
 507 BT_HIDDEN
 508 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 509 {
 510         uint64_t session_idx;
 511
 512         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 513                         session_idx++) {
 514                 struct lttng_live_session *session =
 515                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 516                 session->new_streams_needed = true;
 517         }
 518 }
 519
 520 static
 521 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 522 {
 523         uint64_t session_idx, trace_idx;
 524
 525         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 526                         session_idx++) {
 527                 struct lttng_live_session *session =
 528                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 529                 session->new_streams_needed = true;
 530                 for (trace_idx = 0; trace_idx < session->traces->len;
 531                                 trace_idx++) {
 532                         struct lttng_live_trace *trace =
 533                                 g_ptr_array_index(session->traces, trace_idx);
 534                         trace->new_metadata_needed = true;
 535                 }
 536         }
 537 }
 538
 539 static
 540 enum lttng_live_iterator_status
 541 lttng_live_iterator_handle_new_streams_and_metadata(
 542                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 543 {
 544         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 545         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 546         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 547         uint64_t session_idx = 0, nr_sessions_opened = 0;
 548         struct lttng_live_session *session;
 549         enum session_not_found_action sess_not_found_act =
 550                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 551
 552         /*
 553          * In a remotely distant future, we could add a "new
 554          * session" flag to the protocol, which would tell us that we
 555          * need to query for new sessions even though we have sessions
 556          * currently ongoing.
 557          */
 558         if (lttng_live_msg_iter->sessions->len == 0) {
 559                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 560                         ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 561                         goto end;
 562                 } else {
 563                         /*
 564                          * Retry to create a viewer session for the requested
 565                          * session name.
 566                          */
 567                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
 568                                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 569                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 570                                         "Error creating LTTng live viewer session");
 571                                 goto end;
 572                         }
 573                 }
 574         }
 575
 576         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 577                         session_idx++) {
 578                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 579                                 session_idx);
 580                 ret = lttng_live_get_session(lttng_live_msg_iter, session);
 581                 switch (ret) {
 582                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 583                         break;
 584                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 585                         ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 586                         break;
 587                 default:
 588                         goto end;
 589                 }
 590                 if (!session->closed) {
 591                         nr_sessions_opened++;
 592                 }
 593         }
 594 end:
 595         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK &&
 596                         sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 597                         nr_sessions_opened == 0) {
 598                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 599         }
 600         return ret;
 601 }
 602
 603 static
 604 enum lttng_live_iterator_status emit_inactivity_message(
 605                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 606                 struct lttng_live_stream_iterator *stream_iter,
 607                 bt_message **message, uint64_t timestamp)
 608 {
 609         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 610         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 611         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 612         bt_message *msg = NULL;
 613
 614         BT_ASSERT(stream_iter->trace->clock_class);
 615
 616         msg = bt_message_message_iterator_inactivity_create(
 617                 lttng_live_msg_iter->self_msg_iter,
 618                 stream_iter->trace->clock_class, timestamp);
 619         if (!msg) {
 620                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 621                         "Error emitting message iterator inactivity message");
 622                 goto error;
 623         }
 624
 625         *message = msg;
 626 end:
 627         return ret;
 628
 629 error:
 630         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 631         bt_message_put_ref(msg);
 632         goto end;
 633 }
 634
 635 static
 636 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 637                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 638                 struct lttng_live_stream_iterator *lttng_live_stream,
 639                 bt_message **message)
 640 {
 641         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 642
 643         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 644                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 645         }
 646
 647         if (lttng_live_stream->current_inactivity_ts ==
 648                         lttng_live_stream->last_inactivity_ts) {
 649                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 650                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 651                 goto end;
 652         }
 653
 654         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 655                 message, lttng_live_stream->current_inactivity_ts);
 656
 657         lttng_live_stream->last_inactivity_ts =
 658                 lttng_live_stream->current_inactivity_ts;
 659 end:
 660         return ret;
 661 }
 662
 663 static
 664 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 665                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 666                 const bt_message *msg, int64_t last_msg_ts_ns,
 667                 int64_t *ts_ns)
 668 {
 669         const bt_clock_class *clock_class = NULL;
 670         const bt_clock_snapshot *clock_snapshot = NULL;
 671         int ret = 0;
 672         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 673         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 674
 675         BT_ASSERT_DBG(msg);
 676         BT_ASSERT_DBG(ts_ns);
 677
 678         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 679                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 680                 last_msg_ts_ns);
 681
 682         switch (bt_message_get_type(msg)) {
 683         case BT_MESSAGE_TYPE_EVENT:
 684                 clock_class = bt_message_event_borrow_stream_class_default_clock_class_const(
 685                                 msg);
 686                 BT_ASSERT_DBG(clock_class);
 687
 688                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 689                         msg);
 690                 break;
 691         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 692                 clock_class = bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 693                         msg);
 694                 BT_ASSERT(clock_class);
 695
 696                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 697                         msg);
 698                 break;
 699         case BT_MESSAGE_TYPE_PACKET_END:
 700                 clock_class = bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 701                         msg);
 702                 BT_ASSERT(clock_class);
 703
 704                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 705                         msg);
 706                 break;
 707         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 708                 clock_class = bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 709                         msg);
 710                 BT_ASSERT(clock_class);
 711
 712                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 713                         msg);
 714                 break;
 715         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 716                 clock_class = bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 717                         msg);
 718                 BT_ASSERT(clock_class);
 719
 720                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 721                         msg);
 722                 break;
 723         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 724                 clock_snapshot = bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 725                         msg);
 726                 break;
 727         default:
 728                 /* All the other messages have a higher priority */
 729                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 730                 *ts_ns = last_msg_ts_ns;
 731                 goto end;
 732         }
 733
 734         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 735         BT_ASSERT_DBG(clock_class);
 736
 737         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 738         if (ret) {
 739                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 740                         "Cannot get nanoseconds from Epoch of clock snapshot: "
 741                         "clock-snapshot-addr=%p", clock_snapshot);
 742                 goto error;
 743         }
 744
 745         goto end;
 746
 747 error:
 748         ret = -1;
 749
 750 end:
 751         if (ret == 0) {
 752                 BT_COMP_LOGD("Found message's timestamp: "
 753                         "iter-data-addr=%p, msg-addr=%p, "
 754                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 755                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 756         }
 757
 758         return ret;
 759 }
 760
 761 static
 762 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 763                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 764                 struct lttng_live_stream_iterator *lttng_live_stream,
 765                 bt_message **message)
 766 {
 767         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 768         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 769         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 770         enum bt_msg_iter_status status;
 771         uint64_t session_idx, trace_idx;
 772
 773         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 774                         session_idx++) {
 775                 struct lttng_live_session *session =
 776                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 777
 778                 if (session->new_streams_needed) {
 779                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 780                         goto end;
 781                 }
 782                 for (trace_idx = 0; trace_idx < session->traces->len;
 783                                 trace_idx++) {
 784                         struct lttng_live_trace *trace =
 785                                 g_ptr_array_index(session->traces, trace_idx);
 786                         if (trace->new_metadata_needed) {
 787                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 788                                 goto end;
 789                         }
 790                 }
 791         }
 792
 793         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 794                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 795                 goto end;
 796         }
 797
 798         status = bt_msg_iter_get_next_message(lttng_live_stream->msg_iter,
 799                 lttng_live_msg_iter->self_msg_iter, message);
 800         switch (status) {
 801         case BT_MSG_ITER_STATUS_EOF:
 802                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 803                 break;
 804         case BT_MSG_ITER_STATUS_OK:
 805                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 806                 break;
 807         case BT_MSG_ITER_STATUS_AGAIN:
 808                 /*
 809                  * Continue immediately (end of packet). The next
 810                  * get_index may return AGAIN to delay the following
 811                  * attempt.
 812                  */
 813                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 814                 break;
 815         case BT_MSG_ITER_STATUS_INVAL:
 816                 /* No argument provided by the user, so don't return INVAL. */
 817         case BT_MSG_ITER_STATUS_ERROR:
 818         default:
 819                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 820                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 821                         "CTF message iterator return an error or failed: "
 822                         "msg_iter=%p", lttng_live_stream->msg_iter);
 823                 break;
 824         }
 825
 826 end:
 827         return ret;
 828 }
 829
 830 static
 831 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 832                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 833                 struct lttng_live_stream_iterator *stream_iter,
 834                 bt_message **curr_msg)
 835 {
 836         enum lttng_live_iterator_status live_status =
 837                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 838         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 839         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 840         /*
 841          * The viewer has hung up on us so we are closing the stream. The
 842          * `bt_msg_iter` should simply realize that it needs to close the
 843          * stream properly by emitting the necessary stream end message.
 844          */
 845         enum bt_msg_iter_status status = bt_msg_iter_get_next_message(
 846                 stream_iter->msg_iter, lttng_live_msg_iter->self_msg_iter,
 847                 curr_msg);
 848
 849         if (status == BT_MSG_ITER_STATUS_ERROR) {
 850                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 851                         "Error getting the next message from CTF message iterator");
 852                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 853                 goto end;
 854         }
 855
 856         BT_ASSERT(status == BT_MSG_ITER_STATUS_OK);
 857
 858 end:
 859         return live_status;
 860 }
 861
 862 /*
 863  * helper function:
 864  *            handle_no_data_streams()
 865  *              retry:
 866  *                - for each ACTIVE_NO_DATA stream:
 867  *                  - query relayd for stream data, or quiescence info.
 868  *                    - if need metadata, get metadata, goto retry.
 869  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 870  *                  - if quiescent, move to QUIESCENT streams
 871  *                  - if fetched data, move to ACTIVE_DATA streams
 872  *                (at this point each stream either has data, or is quiescent)
 873  *
 874  *
 875  * iterator_next:
 876  *            handle_new_streams_and_metadata()
 877  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 878  *                  - query relayd for metadata
 879  *
 880  *            call handle_active_no_data_streams()
 881  *
 882  *            handle_quiescent_streams()
 883  *                - if at least one stream is ACTIVE_DATA:
 884  *                  - peek stream event with lowest timestamp -> next_ts
 885  *                  - for each quiescent stream
 886  *                    - if next_ts >= quiescent end
 887  *                      - set state to ACTIVE_NO_DATA
 888  *                - else
 889  *                  - for each quiescent stream
 890  *                      - set state to ACTIVE_NO_DATA
 891  *
 892  *            call handle_active_no_data_streams()
 893  *
 894  *            handle_active_data_streams()
 895  *                - if at least one stream is ACTIVE_DATA:
 896  *                    - get stream event with lowest timestamp from heap
 897  *                    - make that stream event the current message.
 898  *                    - move this stream heap position to its next event
 899  *                      - if we need to fetch data from relayd, move
 900  *                        stream to ACTIVE_NO_DATA.
 901  *                    - return OK
 902  *                - return AGAIN
 903  *
 904  * end criterion: ctrl-c on client. If relayd exits or the session
 905  * closes on the relay daemon side, we keep on waiting for streams.
 906  * Eventually handle --end timestamp (also an end criterion).
 907  *
 908  * When disconnected from relayd: try to re-connect endlessly.
 909  */
 910 static
 911 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 912                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 913                 struct lttng_live_stream_iterator *stream_iter,
 914                 bt_message **curr_msg)
 915 {
 916         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 917         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 918         enum lttng_live_iterator_status live_status;
 919
 920         if (stream_iter->has_stream_hung_up) {
 921                 /*
 922                  * The stream has hung up and the stream was properly closed
 923                  * during the last call to the current function. Return _END
 924                  * status now so that this stream iterator is removed for the
 925                  * stream iterator list.
 926                  */
 927                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 928                 goto end;
 929         }
 930
 931 retry:
 932         print_stream_state(stream_iter);
 933         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 934                 lttng_live_msg_iter);
 935         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 936                 goto end;
 937         }
 938         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 939                 lttng_live_msg_iter, stream_iter);
 940
 941         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 942                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 943                         /*
 944                          * We overwrite `live_status` since `curr_msg` is
 945                          * likely set to a valid message in this function.
 946                          */
 947                         live_status = lttng_live_iterator_close_stream(
 948                                 lttng_live_msg_iter, stream_iter, curr_msg);
 949                 }
 950                 goto end;
 951         }
 952         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 953                 lttng_live_msg_iter, stream_iter, curr_msg);
 954         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 955                 BT_ASSERT(!*curr_msg);
 956                 goto end;
 957         }
 958         if (*curr_msg) {
 959                 goto end;
 960         }
 961         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 962                 lttng_live_msg_iter, stream_iter, curr_msg);
 963         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 964                 BT_ASSERT(!*curr_msg);
 965         }
 966
 967 end:
 968         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 969                 goto retry;
 970         }
 971
 972         return live_status;
 973 }
 974
 975 static
 976 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 977                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 978                 struct lttng_live_trace *live_trace,
 979                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 980 {
 981         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 982         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 983         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 984         enum lttng_live_iterator_status stream_iter_status;;
 985         int64_t youngest_candidate_msg_ts = INT64_MAX;
 986         uint64_t stream_iter_idx;
 987
 988         BT_ASSERT_DBG(live_trace);
 989         BT_ASSERT_DBG(live_trace->stream_iterators);
 990         /*
 991          * Update the current message of every stream iterators of this trace.
 992          * The current msg of every stream must have a timestamp equal or
 993          * larger than the last message returned by this iterator. We must
 994          * ensure monotonicity.
 995          */
 996         stream_iter_idx = 0;
 997         while (stream_iter_idx < live_trace->stream_iterators->len) {
 998                 bool stream_iter_is_ended = false;
 999                 struct lttng_live_stream_iterator *stream_iter =
1000                         g_ptr_array_index(live_trace->stream_iterators,
1001                                 stream_iter_idx);
1002
1003                 /*
1004                  * Find if there is are now current message for this stream
1005                  * iterator get it.
1006                  */
1007                 while (!stream_iter->current_msg) {
1008                         bt_message *msg = NULL;
1009                         int64_t curr_msg_ts_ns = INT64_MAX;
1010                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
1011                                 lttng_live_msg_iter, stream_iter, &msg);
1012
1013                         BT_COMP_LOGD("live stream iterator returned status :%s",
1014                                 print_live_iterator_status(stream_iter_status));
1015                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1016                                 stream_iter_is_ended = true;
1017                                 break;
1018                         }
1019
1020                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1021                                 goto end;
1022                         }
1023
1024                         BT_ASSERT_DBG(msg);
1025
1026                         /*
1027                          * Get the timestamp in nanoseconds from origin of this
1028                          * messsage.
1029                          */
1030                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
1031                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
1032                                 &curr_msg_ts_ns);
1033
1034                         /*
1035                          * Check if the message of the current live stream
1036                          * iterator occured at the exact same time or after the
1037                          * last message returned by this component's message
1038                          * iterator. If not, we return an error.
1039                          */
1040                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
1041                                 stream_iter->current_msg = msg;
1042                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
1043                         } else {
1044                                 /*
1045                                  * We received a message in the past. To ensure
1046                                  * monotonicity, we can't send it forward.
1047                                  */
1048                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1049                                         "Message's timestamp is less than "
1050                                         "lttng-live's message iterator's last "
1051                                         "returned timestamp: "
1052                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1053                                         "last-msg-ts=%" PRId64,
1054                                         lttng_live_msg_iter, curr_msg_ts_ns,
1055                                         lttng_live_msg_iter->last_msg_ts_ns);
1056                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1057                                 goto end;
1058                         }
1059                 }
1060
1061                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1062
1063                 if (!stream_iter_is_ended) {
1064                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1065                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1066                                 /*
1067                                  * Update the current best candidate message
1068                                  * for the stream iterator of this live trace
1069                                  * to be forwarded downstream.
1070                                  */
1071                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1072                                 youngest_candidate_stream_iter = stream_iter;
1073                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1074                                 /*
1075                                  * Order the messages in an arbitrary but
1076                                  * deterministic way.
1077                                  */
1078                                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1079                                 int ret = common_muxing_compare_messages(
1080                                         stream_iter->current_msg,
1081                                         youngest_candidate_stream_iter->current_msg);
1082                                 if (ret < 0) {
1083                                         /*
1084                                          * The `youngest_candidate_stream_iter->current_msg`
1085                                          * should go first. Update the next
1086                                          * iterator and the current timestamp.
1087                                          */
1088                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1089                                         youngest_candidate_stream_iter = stream_iter;
1090                                 } else if (ret == 0) {
1091                                         /*
1092                                          * Unable to pick which one should go
1093                                          * first.
1094                                          */
1095                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1096                                                 "stream-iter-addr=%p"
1097                                                 "stream-iter-addr=%p",
1098                                                 stream_iter,
1099                                                 youngest_candidate_stream_iter);
1100                                 }
1101                         }
1102
1103                         stream_iter_idx++;
1104                 } else {
1105                         /*
1106                          * The live stream iterator has ended. That
1107                          * iterator is removed from the array, but
1108                          * there is no need to increment
1109                          * stream_iter_idx as
1110                          * g_ptr_array_remove_index_fast replaces the
1111                          * removed element with the array's last
1112                          * element.
1113                          */
1114                         g_ptr_array_remove_index_fast(
1115                                 live_trace->stream_iterators,
1116                                 stream_iter_idx);
1117                 }
1118         }
1119
1120         if (youngest_candidate_stream_iter) {
1121                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1122                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1123         } else {
1124                 /*
1125                  * The only case where we don't have a candidate for this trace
1126                  * is if we reached the end of all the iterators.
1127                  */
1128                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1129                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1130         }
1131
1132 end:
1133         return stream_iter_status;
1134 }
1135
1136 static
1137 enum lttng_live_iterator_status next_stream_iterator_for_session(
1138                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1139                 struct lttng_live_session *session,
1140                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1141 {
1142         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1143         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1144         enum lttng_live_iterator_status stream_iter_status;
1145         uint64_t trace_idx = 0;
1146         int64_t youngest_candidate_msg_ts = INT64_MAX;
1147         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1148
1149         /*
1150          * Make sure we are attached to the session and look for new streams
1151          * and metadata.
1152          */
1153         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1154         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1155                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1156                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1157                 goto end;
1158         }
1159
1160         BT_ASSERT_DBG(session->traces);
1161
1162         while (trace_idx < session->traces->len) {
1163                 bool trace_is_ended = false;
1164                 struct lttng_live_stream_iterator *stream_iter;
1165                 struct lttng_live_trace *trace =
1166                         g_ptr_array_index(session->traces, trace_idx);
1167
1168                 stream_iter_status = next_stream_iterator_for_trace(
1169                         lttng_live_msg_iter, trace, &stream_iter);
1170                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1171                         /*
1172                          * All the live stream iterators for this trace are
1173                          * ENDed. Remove the trace from this session.
1174                          */
1175                         trace_is_ended = true;
1176                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1177                         goto end;
1178                 }
1179
1180                 if (!trace_is_ended) {
1181                         BT_ASSERT_DBG(stream_iter);
1182
1183                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1184                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1185                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1186                                 youngest_candidate_stream_iter = stream_iter;
1187                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1188                                 /*
1189                                  * Order the messages in an arbitrary but
1190                                  * deterministic way.
1191                                  */
1192                                 int ret = common_muxing_compare_messages(
1193                                         stream_iter->current_msg,
1194                                         youngest_candidate_stream_iter->current_msg);
1195                                 if (ret < 0) {
1196                                         /*
1197                                          * The `youngest_candidate_stream_iter->current_msg`
1198                                          * should go first. Update the next iterator
1199                                          * and the current timestamp.
1200                                          */
1201                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1202                                         youngest_candidate_stream_iter = stream_iter;
1203                                 } else if (ret == 0) {
1204                                         /* Unable to pick which one should go first. */
1205                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1206                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1207                                                 stream_iter, youngest_candidate_stream_iter);
1208                                 }
1209                         }
1210                         trace_idx++;
1211                 } else {
1212                         /*
1213                          * trace_idx is not incremented since
1214                          * g_ptr_array_remove_index_fast replaces the
1215                          * element at trace_idx with the array's last element.
1216                          */
1217                         g_ptr_array_remove_index_fast(session->traces,
1218                                 trace_idx);
1219                 }
1220         }
1221         if (youngest_candidate_stream_iter) {
1222                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1223                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1224         } else {
1225                 /*
1226                  * The only cases where we don't have a candidate for this
1227                  * trace is:
1228                  *  1. if we reached the end of all the iterators of all the
1229                  *  traces of this session,
1230                  *  2. if we never had live stream iterator in the first place.
1231                  *
1232                  * In either cases, we return END.
1233                  */
1234                 BT_ASSERT(session->traces->len == 0);
1235                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1236         }
1237 end:
1238         return stream_iter_status;
1239 }
1240
1241 static inline
1242 void put_messages(bt_message_array_const msgs, uint64_t count)
1243 {
1244         uint64_t i;
1245
1246         for (i = 0; i < count; i++) {
1247                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1248         }
1249 }
1250
1251 BT_HIDDEN
1252 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1253                 bt_self_message_iterator *self_msg_it,
1254                 bt_message_array_const msgs, uint64_t capacity,
1255                 uint64_t *count)
1256 {
1257         bt_component_class_message_iterator_next_method_status status;
1258         struct lttng_live_msg_iter *lttng_live_msg_iter =
1259                 bt_self_message_iterator_get_data(self_msg_it);
1260         struct lttng_live_component *lttng_live =
1261                 lttng_live_msg_iter->lttng_live_comp;
1262         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1263         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1264         enum lttng_live_iterator_status stream_iter_status;
1265         uint64_t session_idx;
1266
1267         *count = 0;
1268
1269         BT_ASSERT_DBG(lttng_live_msg_iter);
1270
1271         /*
1272          * Clear all the invalid message reference that might be left over in
1273          * the output array.
1274          */
1275         memset(msgs, 0, capacity * sizeof(*msgs));
1276
1277         /*
1278          * If no session are exposed on the relay found at the url provided by
1279          * the user, session count will be 0. In this case, we return status
1280          * end to return gracefully.
1281          */
1282         if (lttng_live_msg_iter->sessions->len == 0) {
1283                 if (lttng_live->params.sess_not_found_act !=
1284                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1285                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1286                         goto no_session;
1287                 } else {
1288                         /*
1289                          * The are no more active session for this session
1290                          * name. Retry to create a viewer session for the
1291                          * requested session name.
1292                          */
1293                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1294                                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1295                                 goto no_session;
1296                         }
1297                 }
1298         }
1299
1300         if (lttng_live_msg_iter->active_stream_iter == 0) {
1301                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1302         }
1303
1304         /*
1305          * Here the muxing of message is done.
1306          *
1307          * We need to iterate over all the streams of all the traces of all the
1308          * viewer sessions in order to get the message with the smallest
1309          * timestamp. In this case, a session is a viewer session and there is
1310          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1311          * kernel). Each viewer session can have multiple traces, for example,
1312          * 64bit UST viewer sessions could have multiple per-pid traces.
1313          *
1314          * We iterate over the streams of each traces to update and see what is
1315          * their next message's timestamp. From those timestamps, we select the
1316          * message with the smallest timestamp as the best candidate message
1317          * for that trace and do the same thing across all the sessions.
1318          *
1319          * We then compare the timestamp of best candidate message of all the
1320          * sessions to pick the message with the smallest timestamp and we
1321          * return it.
1322          */
1323         while (*count < capacity) {
1324                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1325                           *candidate_stream_iter = NULL;
1326                 int64_t youngest_msg_ts_ns = INT64_MAX;
1327
1328                 BT_ASSERT_DBG(lttng_live_msg_iter->sessions);
1329                 session_idx = 0;
1330                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1331                         struct lttng_live_session *session =
1332                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1333                                         session_idx);
1334
1335                         /* Find the best candidate message to send downstream. */
1336                         stream_iter_status = next_stream_iterator_for_session(
1337                                 lttng_live_msg_iter, session,
1338                                 &candidate_stream_iter);
1339
1340                         /* If we receive an END status, it means that either:
1341                          * - Those traces never had active streams (UST with no
1342                          *   data produced yet),
1343                          * - All live stream iterators have ENDed.*/
1344                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1345                                 if (session->closed && session->traces->len == 0) {
1346                                         /*
1347                                          * Remove the session from the list.
1348                                          * session_idx is not modified since
1349                                          * g_ptr_array_remove_index_fast
1350                                          * replaces the the removed element with
1351                                          * the array's last element.
1352                                          */
1353                                         g_ptr_array_remove_index_fast(
1354                                                 lttng_live_msg_iter->sessions,
1355                                                 session_idx);
1356                                 } else {
1357                                         session_idx++;
1358                                 }
1359                                 continue;
1360                         }
1361
1362                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1363                                 goto end;
1364                         }
1365
1366                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1367                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1368                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1369                                 youngest_stream_iter = candidate_stream_iter;
1370                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1371                                 /*
1372                                  * The currently selected message to be sent
1373                                  * downstream next has the exact same timestamp
1374                                  * that of the current candidate message. We
1375                                  * must break the tie in a predictable manner.
1376                                  */
1377                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1378                                 /*
1379                                  * Order the messages in an arbitrary but
1380                                  * deterministic way.
1381                                  */
1382                                 int ret = common_muxing_compare_messages(
1383                                         candidate_stream_iter->current_msg,
1384                                         youngest_stream_iter->current_msg);
1385                                 if (ret < 0) {
1386                                         /*
1387                                          * The `candidate_stream_iter->current_msg`
1388                                          * should go first. Update the next
1389                                          * iterator and the current timestamp.
1390                                          */
1391                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1392                                         youngest_stream_iter = candidate_stream_iter;
1393                                 } else if (ret == 0) {
1394                                         /* Unable to pick which one should go first. */
1395                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1396                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1397                                                 youngest_stream_iter, candidate_stream_iter);
1398                                 }
1399                         }
1400
1401                         session_idx++;
1402                 }
1403
1404                 if (!youngest_stream_iter) {
1405                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1406                         goto end;
1407                 }
1408
1409                 BT_ASSERT_DBG(youngest_stream_iter->current_msg);
1410                 /* Ensure monotonicity. */
1411                 BT_ASSERT_DBG(lttng_live_msg_iter->last_msg_ts_ns <=
1412                         youngest_stream_iter->current_msg_ts_ns);
1413
1414                 /*
1415                  * Insert the next message to the message batch. This will set
1416                  * stream iterator current messsage to NULL so that next time
1417                  * we fetch the next message of that stream iterator
1418                  */
1419                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1420                 (*count)++;
1421
1422                 /* Update the last timestamp in nanoseconds sent downstream. */
1423                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1424                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1425
1426                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1427         }
1428 end:
1429         switch (stream_iter_status) {
1430         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1431         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1432                 if (*count > 0) {
1433                         /*
1434                          * We received a again status but we have some messages
1435                          * to send downstream. We send them and return OK for
1436                          * now. On the next call we return again if there are
1437                          * still no new message to send.
1438                          */
1439                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1440                 } else {
1441                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1442                 }
1443                 break;
1444         case LTTNG_LIVE_ITERATOR_STATUS_END:
1445                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1446                 break;
1447         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1448                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1449                 break;
1450         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1451         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1452         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1453                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1454                 /* Put all existing messages on error. */
1455                 put_messages(msgs, *count);
1456                 break;
1457         default:
1458                 abort();
1459         }
1460
1461 no_session:
1462         return status;
1463 }
1464
1465 BT_HIDDEN
1466 bt_component_class_message_iterator_initialize_method_status lttng_live_msg_iter_init(
1467                 bt_self_message_iterator *self_msg_it,
1468                 bt_self_message_iterator_configuration *config,
1469                 bt_self_component_source *self_comp_src,
1470                 bt_self_component_port_output *self_port)
1471 {
1472         bt_component_class_message_iterator_initialize_method_status ret =
1473                 BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_OK;
1474         bt_self_component *self_comp =
1475                 bt_self_component_source_as_self_component(self_comp_src);
1476         struct lttng_live_component *lttng_live;
1477         struct lttng_live_msg_iter *lttng_live_msg_iter;
1478         bt_logging_level log_level;
1479
1480         BT_ASSERT(self_msg_it);
1481
1482         lttng_live = bt_self_component_get_data(self_comp);
1483         log_level = lttng_live->log_level;
1484         self_comp = lttng_live->self_comp;
1485
1486         /* There can be only one downstream iterator at the same time. */
1487         BT_ASSERT(!lttng_live->has_msg_iter);
1488         lttng_live->has_msg_iter = true;
1489
1490         lttng_live_msg_iter = g_new0(struct lttng_live_msg_iter, 1);
1491         if (!lttng_live_msg_iter) {
1492                 ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1493                 goto end;
1494         }
1495
1496         lttng_live_msg_iter->log_level = lttng_live->log_level;
1497         lttng_live_msg_iter->self_comp = lttng_live->self_comp;
1498         lttng_live_msg_iter->lttng_live_comp = lttng_live;
1499         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1500
1501         lttng_live_msg_iter->active_stream_iter = 0;
1502         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1503         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1504                 (GDestroyNotify) lttng_live_destroy_session);
1505         BT_ASSERT(lttng_live_msg_iter->sessions);
1506
1507         lttng_live_msg_iter->viewer_connection =
1508                 live_viewer_connection_create(lttng_live->params.url->str, false,
1509                         lttng_live_msg_iter, self_comp, NULL, log_level);
1510         if (!lttng_live_msg_iter->viewer_connection) {
1511                 goto error;
1512         }
1513
1514         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1515                 goto error;
1516         }
1517         if (lttng_live_msg_iter->sessions->len == 0) {
1518                 switch (lttng_live->params.sess_not_found_act) {
1519                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1520                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1521                                 "session. Keep trying to connect because of "
1522                                 "%s=\"%s\" component parameter: url=\"%s\"",
1523                                 SESS_NOT_FOUND_ACTION_PARAM,
1524                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1525                                 lttng_live->params.url->str);
1526                         break;
1527                 case SESSION_NOT_FOUND_ACTION_FAIL:
1528                         BT_COMP_LOGE_APPEND_CAUSE(self_comp, "Unable to connect to the requested live viewer "
1529                                 "session. Fail the message iterator"
1530                                 "initialization because of %s=\"%s\" "
1531                                 "component parameter: url =\"%s\"",
1532                                 SESS_NOT_FOUND_ACTION_PARAM,
1533                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1534                                 lttng_live->params.url->str);
1535                         goto error;
1536                 case SESSION_NOT_FOUND_ACTION_END:
1537                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1538                                 "session. End gracefully at the first _next() "
1539                                 "call because of %s=\"%s\" component parameter: "
1540                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1541                                 SESS_NOT_FOUND_ACTION_END_STR,
1542                                 lttng_live->params.url->str);
1543                         break;
1544                 default:
1545                         abort();
1546                 }
1547         }
1548
1549         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1550
1551         goto end;
1552 error:
1553         ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1554         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1555 end:
1556         return ret;
1557 }
1558
1559 static struct bt_param_validation_map_value_entry_descr list_sessions_params[] = {
1560         { URL_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { .type = BT_VALUE_TYPE_STRING } },
1561         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1562 };
1563
1564 static
1565 bt_component_class_query_method_status lttng_live_query_list_sessions(
1566                 const bt_value *params, const bt_value **result,
1567                 bt_self_component_class *self_comp_class,
1568                 bt_logging_level log_level)
1569 {
1570         bt_component_class_query_method_status status;
1571         const bt_value *url_value = NULL;
1572         const char *url;
1573         struct live_viewer_connection *viewer_connection = NULL;
1574         enum bt_param_validation_status validation_status;
1575         gchar *validate_error = NULL;
1576
1577         validation_status = bt_param_validation_validate(params,
1578                 list_sessions_params, &validate_error);
1579         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1580                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1581                 goto error;
1582         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1583                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1584                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class, "%s",
1585                         validate_error);
1586                 goto error;
1587         }
1588
1589         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1590         url = bt_value_string_get(url_value);
1591
1592         viewer_connection = live_viewer_connection_create(url, true, NULL,
1593                 NULL, self_comp_class, log_level);
1594         if (!viewer_connection) {
1595                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1596                         "Failed to create viewer connection");
1597                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1598                 goto error;
1599         }
1600
1601         status = live_viewer_connection_list_sessions(viewer_connection,
1602                 result);
1603         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1604                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1605                         "Failed to list viewer sessions");
1606                 goto error;
1607         }
1608
1609         goto end;
1610
1611 error:
1612         BT_VALUE_PUT_REF_AND_RESET(*result);
1613
1614         if (status >= 0) {
1615                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1616         }
1617
1618 end:
1619         if (viewer_connection) {
1620                 live_viewer_connection_destroy(viewer_connection);
1621         }
1622
1623         g_free(validate_error);
1624
1625         return status;
1626 }
1627
1628 static
1629 bt_component_class_query_method_status lttng_live_query_support_info(
1630                 const bt_value *params, const bt_value **result,
1631                 bt_self_component_class *self_comp_class,
1632                 bt_logging_level log_level)
1633 {
1634         bt_component_class_query_method_status status =
1635                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1636         const bt_value *input_type_value;
1637         const bt_value *input_value;
1638         double weight = 0;
1639         struct bt_common_lttng_live_url_parts parts = { 0 };
1640
1641         /* Used by the logging macros */
1642         __attribute__((unused)) bt_self_component *self_comp = NULL;
1643
1644         *result = NULL;
1645         input_type_value = bt_value_map_borrow_entry_value_const(params,
1646                 "type");
1647         if (!input_type_value) {
1648                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1649                         "Missing expected `type` parameter.");
1650                 goto error;
1651         }
1652
1653         if (!bt_value_is_string(input_type_value)) {
1654                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1655                         "`type` parameter is not a string value.");
1656                 goto error;
1657         }
1658
1659         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1660                 /* We don't handle file system paths */
1661                 goto create_result;
1662         }
1663
1664         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1665         if (!input_value) {
1666                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1667                         "Missing expected `input` parameter.");
1668                 goto error;
1669         }
1670
1671         if (!bt_value_is_string(input_value)) {
1672                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1673                         "`input` parameter is not a string value.");
1674                 goto error;
1675         }
1676
1677         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1678                 NULL, 0);
1679         if (parts.session_name) {
1680                 /*
1681                  * Looks pretty much like an LTTng live URL: we got the
1682                  * session name part, which forms a complete URL.
1683                  */
1684                 weight = .75;
1685         }
1686
1687 create_result:
1688         *result = bt_value_real_create_init(weight);
1689         if (!*result) {
1690                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1691                 goto error;
1692         }
1693
1694         goto end;
1695
1696 error:
1697         if (status >= 0) {
1698                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1699         }
1700
1701         BT_ASSERT(!*result);
1702
1703 end:
1704         bt_common_destroy_lttng_live_url_parts(&parts);
1705         return status;
1706 }
1707
1708 BT_HIDDEN
1709 bt_component_class_query_method_status lttng_live_query(
1710                 bt_self_component_class_source *comp_class,
1711                 bt_private_query_executor *priv_query_exec,
1712                 const char *object, const bt_value *params,
1713                 __attribute__((unused)) void *method_data,
1714                 const bt_value **result)
1715 {
1716         bt_component_class_query_method_status status =
1717                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1718         bt_self_component *self_comp = NULL;
1719         bt_self_component_class *self_comp_class =
1720                 bt_self_component_class_source_as_self_component_class(comp_class);
1721         bt_logging_level log_level = bt_query_executor_get_logging_level(
1722                 bt_private_query_executor_as_query_executor_const(
1723                         priv_query_exec));
1724
1725         if (strcmp(object, "sessions") == 0) {
1726                 status = lttng_live_query_list_sessions(params, result,
1727                         self_comp_class, log_level);
1728         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1729                 status = lttng_live_query_support_info(params, result,
1730                         self_comp_class, log_level);
1731         } else {
1732                 BT_COMP_LOGI("Unknown query object `%s`", object);
1733                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1734                 goto end;
1735         }
1736
1737 end:
1738         return status;
1739 }
1740
1741 static
1742 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1743 {
1744         if (!lttng_live) {
1745                 return;
1746         }
1747         if (lttng_live->params.url) {
1748                 g_string_free(lttng_live->params.url, TRUE);
1749         }
1750         g_free(lttng_live);
1751 }
1752
1753 BT_HIDDEN
1754 void lttng_live_component_finalize(bt_self_component_source *component)
1755 {
1756         void *data = bt_self_component_get_data(
1757                 bt_self_component_source_as_self_component(component));
1758
1759         if (!data) {
1760                 return;
1761         }
1762         lttng_live_component_destroy_data(data);
1763 }
1764
1765 static
1766 enum session_not_found_action parse_session_not_found_action_param(
1767         const bt_value *no_session_param)
1768 {
1769         enum session_not_found_action action;
1770         const char *no_session_act_str = bt_value_string_get(no_session_param);
1771
1772         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1773                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1774         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1775                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1776         } else {
1777                 BT_ASSERT(strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0);
1778                 action = SESSION_NOT_FOUND_ACTION_END;
1779         }
1780
1781         return action;
1782 }
1783
1784 static struct bt_param_validation_value_descr inputs_elem_descr = {
1785         .type = BT_VALUE_TYPE_STRING,
1786 };
1787
1788 static const char *sess_not_found_action_choices[] = {
1789         SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1790         SESS_NOT_FOUND_ACTION_FAIL_STR,
1791         SESS_NOT_FOUND_ACTION_END_STR,
1792 };
1793
1794 static struct bt_param_validation_map_value_entry_descr params_descr[] = {
1795         { INPUTS_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { BT_VALUE_TYPE_ARRAY, .array = {
1796                 .min_length = 1,
1797                 .max_length = 1,
1798                 .element_type = &inputs_elem_descr,
1799         } } },
1800         { SESS_NOT_FOUND_ACTION_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL, { BT_VALUE_TYPE_STRING, .string = {
1801                 .choices = sess_not_found_action_choices,
1802         } } },
1803         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1804 };
1805
1806 static
1807 bt_component_class_initialize_method_status lttng_live_component_create(
1808                 const bt_value *params,
1809                 bt_logging_level log_level,
1810                 bt_self_component *self_comp,
1811                 struct lttng_live_component **component)
1812 {
1813         struct lttng_live_component *lttng_live = NULL;
1814         const bt_value *inputs_value;
1815         const bt_value *url_value;
1816         const bt_value *value;
1817         const char *url;
1818         enum bt_param_validation_status validation_status;
1819         gchar *validation_error = NULL;
1820         bt_component_class_initialize_method_status status;
1821
1822         validation_status = bt_param_validation_validate(params, params_descr,
1823                 &validation_error);
1824         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1825                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1826                 goto error;
1827         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1828                 BT_COMP_LOGE_APPEND_CAUSE(self_comp, "%s", validation_error);
1829                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
1830                 goto error;
1831         }
1832
1833         lttng_live = g_new0(struct lttng_live_component, 1);
1834         if (!lttng_live) {
1835                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1836                 goto end;
1837         }
1838         lttng_live->log_level = log_level;
1839         lttng_live->self_comp = self_comp;
1840         lttng_live->max_query_size = MAX_QUERY_SIZE;
1841         lttng_live->has_msg_iter = false;
1842
1843         inputs_value =
1844                 bt_value_map_borrow_entry_value_const(params, INPUTS_PARAM);
1845         url_value =
1846                 bt_value_array_borrow_element_by_index_const(inputs_value, 0);
1847         url = bt_value_string_get(url_value);
1848
1849         lttng_live->params.url = g_string_new(url);
1850         if (!lttng_live->params.url) {
1851                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1852                 goto error;
1853         }
1854
1855         value = bt_value_map_borrow_entry_value_const(params,
1856                 SESS_NOT_FOUND_ACTION_PARAM);
1857         if (value) {
1858                 lttng_live->params.sess_not_found_act =
1859                         parse_session_not_found_action_param(value);
1860         } else {
1861                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1862                         "defaulting to `%s`.",
1863                         SESS_NOT_FOUND_ACTION_PARAM,
1864                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1865                 lttng_live->params.sess_not_found_act =
1866                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1867         }
1868
1869         status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;
1870         goto end;
1871
1872 error:
1873         lttng_live_component_destroy_data(lttng_live);
1874         lttng_live = NULL;
1875 end:
1876         g_free(validation_error);
1877
1878         *component = lttng_live;
1879         return status;
1880 }
1881
1882 BT_HIDDEN
1883 bt_component_class_initialize_method_status lttng_live_component_init(
1884                 bt_self_component_source *self_comp_src,
1885                 bt_self_component_source_configuration *config,
1886                 const bt_value *params,
1887                 __attribute__((unused)) void *init_method_data)
1888 {
1889         struct lttng_live_component *lttng_live;
1890         bt_component_class_initialize_method_status ret;
1891         bt_self_component *self_comp =
1892                 bt_self_component_source_as_self_component(self_comp_src);
1893         bt_logging_level log_level = bt_component_get_logging_level(
1894                 bt_self_component_as_component(self_comp));
1895         bt_self_component_add_port_status add_port_status;
1896
1897         ret = lttng_live_component_create(params, log_level, self_comp, &lttng_live);
1898         if (ret != BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK) {
1899                 goto error;
1900         }
1901
1902         add_port_status = bt_self_component_source_add_output_port(
1903                 self_comp_src, "out", NULL, NULL);
1904         if (add_port_status != BT_SELF_COMPONENT_ADD_PORT_STATUS_OK) {
1905                 ret = (int) add_port_status;
1906                 goto end;
1907         }
1908
1909         bt_self_component_set_data(self_comp, lttng_live);
1910         goto end;
1911
1912 error:
1913         lttng_live_component_destroy_data(lttng_live);
1914         lttng_live = NULL;
1915 end:
1916         return ret;
1917 }