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 <inttypes.h>
  37 #include <stdbool.h>
  38 #include <unistd.h>
  39
  40 #include <glib.h>
  41
  42 #include "common/assert.h"
  43 #include <babeltrace2/babeltrace.h>
  44 #include "compat/compiler.h"
  45 #include <babeltrace2/types.h>
  46
  47 #include "plugins/common/muxing/muxing.h"
  48 #include "plugins/common/param-validation/param-validation.h"
  49
  50 #include "data-stream.h"
  51 #include "metadata.h"
  52 #include "lttng-live.h"
  53
  54 #define MAX_QUERY_SIZE                      (256*1024)
  55 #define URL_PARAM                           "url"
  56 #define INPUTS_PARAM                        "inputs"
  57 #define SESS_NOT_FOUND_ACTION_PARAM         "session-not-found-action"
  58 #define SESS_NOT_FOUND_ACTION_CONTINUE_STR  "continue"
  59 #define SESS_NOT_FOUND_ACTION_FAIL_STR      "fail"
  60 #define SESS_NOT_FOUND_ACTION_END_STR       "end"
  61
  62 #define print_dbg(fmt, ...)     BT_COMP_LOGD(fmt, ## __VA_ARGS__)
  63
  64 static
  65 const char *lttng_live_iterator_status_string(
  66                 enum lttng_live_iterator_status status)
  67 {
  68         switch (status) {
  69         case LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
  70                 return "LTTNG_LIVE_ITERATOR_STATUS_CONTINUE";
  71         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
  72                 return "LTTNG_LIVE_ITERATOR_STATUS_AGAIN";
  73         case LTTNG_LIVE_ITERATOR_STATUS_END:
  74                 return "LTTNG_LIVE_ITERATOR_STATUS_END";
  75         case LTTNG_LIVE_ITERATOR_STATUS_OK:
  76                 return "LTTNG_LIVE_ITERATOR_STATUS_OK";
  77         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
  78                 return "LTTNG_LIVE_ITERATOR_STATUS_INVAL";
  79         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
  80                 return "LTTNG_LIVE_ITERATOR_STATUS_ERROR";
  81         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
  82                 return "LTTNG_LIVE_ITERATOR_STATUS_NOMEM";
  83         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
  84                 return "LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED";
  85         default:
  86                 bt_common_abort();
  87         }
  88 }
  89
  90 static
  91 const char *print_state(struct lttng_live_stream_iterator *s)
  92 {
  93         switch (s->state) {
  94         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
  95                 return "ACTIVE_NO_DATA";
  96         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
  97                 return "QUIESCENT_NO_DATA";
  98         case LTTNG_LIVE_STREAM_QUIESCENT:
  99                 return "QUIESCENT";
 100         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
 101                 return "ACTIVE_DATA";
 102         case LTTNG_LIVE_STREAM_EOF:
 103                 return "EOF";
 104         default:
 105                 return "ERROR";
 106         }
 107 }
 108
 109 #define print_stream_state(live_stream_iter) \
 110         do { \
 111                 BT_COMP_LOGD("stream state %s last_inact_ts %" PRId64  \
 112                         ", curr_inact_ts %" PRId64, \
 113                         print_state(live_stream_iter), \
 114                         live_stream_iter->last_inactivity_ts, \
 115                         live_stream_iter->current_inactivity_ts); \
 116         } while (0);
 117
 118 BT_HIDDEN
 119 bool lttng_live_graph_is_canceled(struct lttng_live_msg_iter *msg_iter)
 120 {
 121         bool ret;
 122
 123         if (!msg_iter) {
 124                 ret = false;
 125                 goto end;
 126         }
 127
 128         ret = bt_self_message_iterator_is_interrupted(
 129                 msg_iter->self_msg_iter);
 130
 131 end:
 132         return ret;
 133 }
 134
 135 static
 136 struct lttng_live_trace *lttng_live_find_trace(struct lttng_live_session *session,
 137                 uint64_t trace_id)
 138 {
 139         uint64_t trace_idx;
 140         struct lttng_live_trace *ret_trace = NULL;
 141
 142         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 143                 struct lttng_live_trace *trace =
 144                         g_ptr_array_index(session->traces, trace_idx);
 145                 if (trace->id == trace_id) {
 146                         ret_trace = trace;
 147                         goto end;
 148                 }
 149         }
 150
 151 end:
 152         return ret_trace;
 153 }
 154
 155 static
 156 void lttng_live_destroy_trace(struct lttng_live_trace *trace)
 157 {
 158         bt_logging_level log_level = trace->log_level;
 159         bt_self_component *self_comp = trace->self_comp;
 160
 161         BT_COMP_LOGD("Destroy lttng_live_trace");
 162
 163         BT_ASSERT(trace->stream_iterators);
 164         g_ptr_array_free(trace->stream_iterators, TRUE);
 165
 166         BT_TRACE_PUT_REF_AND_RESET(trace->trace);
 167         BT_TRACE_CLASS_PUT_REF_AND_RESET(trace->trace_class);
 168
 169         lttng_live_metadata_fini(trace);
 170         g_free(trace);
 171 }
 172
 173 static
 174 struct lttng_live_trace *lttng_live_create_trace(struct lttng_live_session *session,
 175                 uint64_t trace_id)
 176 {
 177         struct lttng_live_trace *trace = NULL;
 178         bt_logging_level log_level = session->log_level;
 179         bt_self_component *self_comp = session->self_comp;
 180
 181         trace = g_new0(struct lttng_live_trace, 1);
 182         if (!trace) {
 183                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 184                         "Failed to allocate live trace");
 185                 goto error;
 186         }
 187         trace->log_level = session->log_level;
 188         trace->self_comp = session->self_comp;
 189         trace->session = session;
 190         trace->id = trace_id;
 191         trace->trace_class = NULL;
 192         trace->trace = NULL;
 193         trace->stream_iterators = g_ptr_array_new_with_free_func(
 194                 (GDestroyNotify) lttng_live_stream_iterator_destroy);
 195         BT_ASSERT(trace->stream_iterators);
 196         trace->new_metadata_needed = true;
 197         g_ptr_array_add(session->traces, trace);
 198
 199         BT_COMP_LOGI("Create trace");
 200         goto end;
 201 error:
 202         g_free(trace);
 203         trace = NULL;
 204 end:
 205         return trace;
 206 }
 207
 208 BT_HIDDEN
 209 struct lttng_live_trace *lttng_live_borrow_trace(
 210                 struct lttng_live_session *session, uint64_t trace_id)
 211 {
 212         struct lttng_live_trace *trace;
 213
 214         trace = lttng_live_find_trace(session, trace_id);
 215         if (trace) {
 216                 goto end;
 217         }
 218
 219         /* The session is the owner of the newly created trace. */
 220         trace = lttng_live_create_trace(session, trace_id);
 221
 222 end:
 223         return trace;
 224 }
 225
 226 BT_HIDDEN
 227 int lttng_live_add_session(struct lttng_live_msg_iter *lttng_live_msg_iter,
 228                 uint64_t session_id, const char *hostname,
 229                 const char *session_name)
 230 {
 231         int ret = 0;
 232         struct lttng_live_session *session;
 233         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 234         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 235
 236         session = g_new0(struct lttng_live_session, 1);
 237         if (!session) {
 238                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 239                         "Failed to allocate live session");
 240                 goto error;
 241         }
 242
 243         session->log_level = lttng_live_msg_iter->log_level;
 244         session->self_comp = lttng_live_msg_iter->self_comp;
 245         session->id = session_id;
 246         session->traces = g_ptr_array_new_with_free_func(
 247                 (GDestroyNotify) lttng_live_destroy_trace);
 248         BT_ASSERT(session->traces);
 249         session->lttng_live_msg_iter = lttng_live_msg_iter;
 250         session->new_streams_needed = true;
 251         session->hostname = g_string_new(hostname);
 252         BT_ASSERT(session->hostname);
 253
 254         session->session_name = g_string_new(session_name);
 255         BT_ASSERT(session->session_name);
 256
 257         BT_COMP_LOGI("Reading from session: %" PRIu64 " hostname: %s session_name: %s",
 258                 session->id, hostname, session_name);
 259         g_ptr_array_add(lttng_live_msg_iter->sessions, session);
 260         goto end;
 261 error:
 262         g_free(session);
 263         ret = -1;
 264 end:
 265         return ret;
 266 }
 267
 268 static
 269 void lttng_live_destroy_session(struct lttng_live_session *session)
 270 {
 271         bt_logging_level log_level;
 272         bt_self_component *self_comp;
 273
 274         if (!session) {
 275                 goto end;
 276         }
 277
 278         log_level = session->log_level;
 279         self_comp = session->self_comp;
 280         BT_COMP_LOGD("Destroy lttng live session");
 281         if (session->id != -1ULL) {
 282                 if (lttng_live_detach_session(session)) {
 283                         if (!lttng_live_graph_is_canceled(
 284                                         session->lttng_live_msg_iter)) {
 285                                 /* Old relayd cannot detach sessions. */
 286                                 BT_COMP_LOGD("Unable to detach lttng live session %" PRIu64,
 287                                         session->id);
 288                         }
 289                 }
 290                 session->id = -1ULL;
 291         }
 292
 293         if (session->traces) {
 294                 g_ptr_array_free(session->traces, TRUE);
 295         }
 296
 297         if (session->hostname) {
 298                 g_string_free(session->hostname, TRUE);
 299         }
 300         if (session->session_name) {
 301                 g_string_free(session->session_name, TRUE);
 302         }
 303         g_free(session);
 304
 305 end:
 306         return;
 307 }
 308
 309 static
 310 void lttng_live_msg_iter_destroy(struct lttng_live_msg_iter *lttng_live_msg_iter)
 311 {
 312         if (!lttng_live_msg_iter) {
 313                 goto end;
 314         }
 315
 316         if (lttng_live_msg_iter->sessions) {
 317                 g_ptr_array_free(lttng_live_msg_iter->sessions, TRUE);
 318         }
 319
 320         if (lttng_live_msg_iter->viewer_connection) {
 321                 live_viewer_connection_destroy(lttng_live_msg_iter->viewer_connection);
 322         }
 323         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp);
 324         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp->has_msg_iter);
 325
 326         /* All stream iterators must be destroyed at this point. */
 327         BT_ASSERT(lttng_live_msg_iter->active_stream_iter == 0);
 328         lttng_live_msg_iter->lttng_live_comp->has_msg_iter = false;
 329
 330         g_free(lttng_live_msg_iter);
 331
 332 end:
 333         return;
 334 }
 335
 336 BT_HIDDEN
 337 void lttng_live_msg_iter_finalize(bt_self_message_iterator *self_msg_iter)
 338 {
 339         struct lttng_live_msg_iter *lttng_live_msg_iter;
 340
 341         BT_ASSERT(self_msg_iter);
 342
 343         lttng_live_msg_iter = bt_self_message_iterator_get_data(self_msg_iter);
 344         BT_ASSERT(lttng_live_msg_iter);
 345         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
 346 }
 347
 348 static
 349 enum lttng_live_iterator_status lttng_live_iterator_next_check_stream_state(
 350                 struct lttng_live_stream_iterator *lttng_live_stream)
 351 {
 352         bt_logging_level log_level = lttng_live_stream->log_level;
 353         bt_self_component *self_comp = lttng_live_stream->self_comp;
 354
 355         switch (lttng_live_stream->state) {
 356         case LTTNG_LIVE_STREAM_QUIESCENT:
 357         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
 358                 break;
 359         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
 360                 /* Invalid state. */
 361                 BT_COMP_LOGF("Unexpected stream state \"ACTIVE_NO_DATA\"");
 362                 bt_common_abort();
 363         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
 364                 /* Invalid state. */
 365                 BT_COMP_LOGF("Unexpected stream state \"QUIESCENT_NO_DATA\"");
 366                 bt_common_abort();
 367         case LTTNG_LIVE_STREAM_EOF:
 368                 break;
 369         }
 370         return LTTNG_LIVE_ITERATOR_STATUS_OK;
 371 }
 372
 373 /*
 374  * For active no data stream, fetch next data. It can be either:
 375  * - quiescent: need to put it in the prio heap at quiescent end
 376  *   timestamp,
 377  * - have data: need to wire up first event into the prio heap,
 378  * - have no data on this stream at this point: need to retry (AGAIN) or
 379  *   return EOF.
 380  */
 381 static
 382 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_no_data_stream(
 383                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 384                 struct lttng_live_stream_iterator *lttng_live_stream)
 385 {
 386         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 387         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 388         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 389         enum lttng_live_stream_state orig_state = lttng_live_stream->state;
 390         struct packet_index index;
 391
 392         if (lttng_live_stream->trace->new_metadata_needed) {
 393                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 394                 goto end;
 395         }
 396         if (lttng_live_stream->trace->session->new_streams_needed) {
 397                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 398                 goto end;
 399         }
 400         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_NO_DATA &&
 401                         lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA) {
 402                 goto end;
 403         }
 404         ret = lttng_live_get_next_index(lttng_live_msg_iter, lttng_live_stream,
 405                 &index);
 406         if (ret != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 407                 goto end;
 408         }
 409         BT_ASSERT_DBG(lttng_live_stream->state != LTTNG_LIVE_STREAM_EOF);
 410         if (lttng_live_stream->state == LTTNG_LIVE_STREAM_QUIESCENT) {
 411                 uint64_t last_inact_ts = lttng_live_stream->last_inactivity_ts,
 412                          curr_inact_ts = lttng_live_stream->current_inactivity_ts;
 413
 414                 if (orig_state == LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA &&
 415                                 last_inact_ts == curr_inact_ts) {
 416                         ret = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 417                         print_stream_state(lttng_live_stream);
 418                 } else {
 419                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 420                 }
 421                 goto end;
 422         }
 423         lttng_live_stream->base_offset = index.offset;
 424         lttng_live_stream->offset = index.offset;
 425         lttng_live_stream->len = index.packet_size / CHAR_BIT;
 426 end:
 427         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK) {
 428                 ret = lttng_live_iterator_next_check_stream_state(lttng_live_stream);
 429         }
 430         return ret;
 431 }
 432
 433 /*
 434  * Creation of the message requires the ctf trace class to be created
 435  * beforehand, but the live protocol gives us all streams (including metadata)
 436  * at once. So we split it in three steps: getting streams, getting metadata
 437  * (which creates the ctf trace class), and then creating the per-stream
 438  * messages.
 439  */
 440 static
 441 enum lttng_live_iterator_status lttng_live_get_session(
 442                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 443                 struct lttng_live_session *session)
 444 {
 445         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 446         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 447         enum lttng_live_iterator_status status;
 448         uint64_t trace_idx;
 449
 450         if (!session->attached) {
 451                 enum lttng_live_viewer_status attach_status =
 452                         lttng_live_attach_session(session,
 453                                 lttng_live_msg_iter->self_msg_iter);
 454                 if (attach_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 455                         if (lttng_live_graph_is_canceled(lttng_live_msg_iter)) {
 456                                 /*
 457                                  * Clear any causes appended in
 458                                  * `lttng_live_attach_session()` as we want to
 459                                  * return gracefully since the graph was
 460                                  * cancelled.
 461                                  */
 462                                 bt_current_thread_clear_error();
 463                                 status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 464                         } else {
 465                                 status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 466                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 467                                         "Error attaching to LTTng live session");
 468                         }
 469                         goto end;
 470                 }
 471         }
 472
 473         status = lttng_live_get_new_streams(session,
 474                 lttng_live_msg_iter->self_msg_iter);
 475         if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 476                         status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 477                 goto end;
 478         }
 479         trace_idx = 0;
 480         while (trace_idx < session->traces->len) {
 481                 struct lttng_live_trace *trace =
 482                         g_ptr_array_index(session->traces, trace_idx);
 483
 484                 status = lttng_live_metadata_update(trace);
 485                 switch (status) {
 486                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 487                         trace_idx++;
 488                         break;
 489                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 490                         /*
 491                          * The trace has ended. Remove it of the array an
 492                          * continue the iteration.
 493                          * We can remove the trace safely when using the
 494                          * g_ptr_array_remove_index_fast because it replaces
 495                          * the element at trace_idx with the array's last
 496                          * element. trace_idx is not incremented because of
 497                          * that.
 498                          */
 499                         (void) g_ptr_array_remove_index_fast(session->traces,
 500                                 trace_idx);
 501                         break;
 502                 default:
 503                         goto end;
 504                 }
 505         }
 506         status = lttng_live_lazy_msg_init(session,
 507                 lttng_live_msg_iter->self_msg_iter);
 508
 509 end:
 510         return status;
 511 }
 512
 513 BT_HIDDEN
 514 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 515 {
 516         uint64_t session_idx;
 517
 518         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 519                         session_idx++) {
 520                 struct lttng_live_session *session =
 521                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 522                 session->new_streams_needed = true;
 523         }
 524 }
 525
 526 static
 527 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 528 {
 529         uint64_t session_idx, trace_idx;
 530
 531         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 532                         session_idx++) {
 533                 struct lttng_live_session *session =
 534                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 535                 session->new_streams_needed = true;
 536                 for (trace_idx = 0; trace_idx < session->traces->len;
 537                                 trace_idx++) {
 538                         struct lttng_live_trace *trace =
 539                                 g_ptr_array_index(session->traces, trace_idx);
 540                         trace->new_metadata_needed = true;
 541                 }
 542         }
 543 }
 544
 545 static
 546 enum lttng_live_iterator_status
 547 lttng_live_iterator_handle_new_streams_and_metadata(
 548                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 549 {
 550         enum lttng_live_iterator_status status;
 551         enum lttng_live_viewer_status viewer_status;
 552         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 553         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 554         uint64_t session_idx = 0, nr_sessions_opened = 0;
 555         struct lttng_live_session *session;
 556         enum session_not_found_action sess_not_found_act =
 557                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 558
 559         /*
 560          * In a remotely distant future, we could add a "new
 561          * session" flag to the protocol, which would tell us that we
 562          * need to query for new sessions even though we have sessions
 563          * currently ongoing.
 564          */
 565         if (lttng_live_msg_iter->sessions->len == 0) {
 566                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 567                         status = LTTNG_LIVE_ITERATOR_STATUS_END;
 568                         goto end;
 569                 } else {
 570                         /*
 571                          * Retry to create a viewer session for the requested
 572                          * session name.
 573                          */
 574                         viewer_status = lttng_live_create_viewer_session(lttng_live_msg_iter);
 575                         if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 576                                 if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
 577                                         status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 578                                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 579                                                 "Error creating LTTng live viewer session");
 580                                 } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
 581                                         status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 582                                 } else {
 583                                         bt_common_abort();
 584                                 }
 585                                 goto end;
 586                         }
 587                 }
 588         }
 589
 590         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 591                         session_idx++) {
 592                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 593                                 session_idx);
 594                 status = lttng_live_get_session(lttng_live_msg_iter, session);
 595                 switch (status) {
 596                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 597                         break;
 598                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 599                         status = LTTNG_LIVE_ITERATOR_STATUS_OK;
 600                         break;
 601                 default:
 602                         goto end;
 603                 }
 604                 if (!session->closed) {
 605                         nr_sessions_opened++;
 606                 }
 607         }
 608
 609         if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 610                         nr_sessions_opened == 0) {
 611                 status = LTTNG_LIVE_ITERATOR_STATUS_END;
 612         } else {
 613                 status = LTTNG_LIVE_ITERATOR_STATUS_OK;
 614         }
 615
 616 end:
 617         return status;
 618 }
 619
 620 static
 621 enum lttng_live_iterator_status emit_inactivity_message(
 622                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 623                 struct lttng_live_stream_iterator *stream_iter,
 624                 bt_message **message, uint64_t timestamp)
 625 {
 626         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 627         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 628         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 629         bt_message *msg = NULL;
 630
 631         BT_ASSERT(stream_iter->trace->clock_class);
 632
 633         msg = bt_message_message_iterator_inactivity_create(
 634                 lttng_live_msg_iter->self_msg_iter,
 635                 stream_iter->trace->clock_class, timestamp);
 636         if (!msg) {
 637                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 638                         "Error emitting message iterator inactivity message");
 639                 goto error;
 640         }
 641
 642         *message = msg;
 643 end:
 644         return ret;
 645
 646 error:
 647         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 648         bt_message_put_ref(msg);
 649         goto end;
 650 }
 651
 652 static
 653 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 654                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 655                 struct lttng_live_stream_iterator *lttng_live_stream,
 656                 bt_message **message)
 657 {
 658         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 659
 660         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 661                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 662         }
 663
 664         if (lttng_live_stream->current_inactivity_ts ==
 665                         lttng_live_stream->last_inactivity_ts) {
 666                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 667                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 668                 goto end;
 669         }
 670
 671         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 672                 message, lttng_live_stream->current_inactivity_ts);
 673
 674         lttng_live_stream->last_inactivity_ts =
 675                 lttng_live_stream->current_inactivity_ts;
 676 end:
 677         return ret;
 678 }
 679
 680 static
 681 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 682                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 683                 const bt_message *msg, int64_t last_msg_ts_ns,
 684                 int64_t *ts_ns)
 685 {
 686         const bt_clock_class *clock_class = NULL;
 687         const bt_clock_snapshot *clock_snapshot = NULL;
 688         int ret = 0;
 689         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 690         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 691
 692         BT_ASSERT_DBG(msg);
 693         BT_ASSERT_DBG(ts_ns);
 694
 695         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 696                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 697                 last_msg_ts_ns);
 698
 699         switch (bt_message_get_type(msg)) {
 700         case BT_MESSAGE_TYPE_EVENT:
 701                 clock_class = bt_message_event_borrow_stream_class_default_clock_class_const(
 702                                 msg);
 703                 BT_ASSERT_DBG(clock_class);
 704
 705                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 706                         msg);
 707                 break;
 708         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 709                 clock_class = bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 710                         msg);
 711                 BT_ASSERT(clock_class);
 712
 713                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 714                         msg);
 715                 break;
 716         case BT_MESSAGE_TYPE_PACKET_END:
 717                 clock_class = bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 718                         msg);
 719                 BT_ASSERT(clock_class);
 720
 721                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 722                         msg);
 723                 break;
 724         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 725                 clock_class = bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 726                         msg);
 727                 BT_ASSERT(clock_class);
 728
 729                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 730                         msg);
 731                 break;
 732         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 733                 clock_class = bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 734                         msg);
 735                 BT_ASSERT(clock_class);
 736
 737                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 738                         msg);
 739                 break;
 740         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 741                 clock_snapshot = bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 742                         msg);
 743                 break;
 744         default:
 745                 /* All the other messages have a higher priority */
 746                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 747                 *ts_ns = last_msg_ts_ns;
 748                 goto end;
 749         }
 750
 751         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 752         BT_ASSERT_DBG(clock_class);
 753
 754         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 755         if (ret) {
 756                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 757                         "Cannot get nanoseconds from Epoch of clock snapshot: "
 758                         "clock-snapshot-addr=%p", clock_snapshot);
 759                 goto error;
 760         }
 761
 762         goto end;
 763
 764 error:
 765         ret = -1;
 766
 767 end:
 768         if (ret == 0) {
 769                 BT_COMP_LOGD("Found message's timestamp: "
 770                         "iter-data-addr=%p, msg-addr=%p, "
 771                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 772                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 773         }
 774
 775         return ret;
 776 }
 777
 778 static
 779 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 780                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 781                 struct lttng_live_stream_iterator *lttng_live_stream,
 782                 bt_message **message)
 783 {
 784         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 785         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 786         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 787         enum ctf_msg_iter_status status;
 788         uint64_t session_idx, trace_idx;
 789
 790         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 791                         session_idx++) {
 792                 struct lttng_live_session *session =
 793                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 794
 795                 if (session->new_streams_needed) {
 796                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 797                         goto end;
 798                 }
 799                 for (trace_idx = 0; trace_idx < session->traces->len;
 800                                 trace_idx++) {
 801                         struct lttng_live_trace *trace =
 802                                 g_ptr_array_index(session->traces, trace_idx);
 803                         if (trace->new_metadata_needed) {
 804                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 805                                 goto end;
 806                         }
 807                 }
 808         }
 809
 810         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 811                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 812                 goto end;
 813         }
 814
 815         status = ctf_msg_iter_get_next_message(
 816                 lttng_live_stream->msg_iter, message);
 817         switch (status) {
 818         case CTF_MSG_ITER_STATUS_EOF:
 819                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 820                 break;
 821         case CTF_MSG_ITER_STATUS_OK:
 822                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 823                 break;
 824         case CTF_MSG_ITER_STATUS_AGAIN:
 825                 /*
 826                  * Continue immediately (end of packet). The next
 827                  * get_index may return AGAIN to delay the following
 828                  * attempt.
 829                  */
 830                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 831                 break;
 832         case CTF_MSG_ITER_STATUS_INVAL:
 833                 /* No argument provided by the user, so don't return INVAL. */
 834         case CTF_MSG_ITER_STATUS_ERROR:
 835         default:
 836                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 837                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 838                         "CTF message iterator return an error or failed: "
 839                         "msg_iter=%p", lttng_live_stream->msg_iter);
 840                 break;
 841         }
 842
 843 end:
 844         return ret;
 845 }
 846
 847 static
 848 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 849                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 850                 struct lttng_live_stream_iterator *stream_iter,
 851                 bt_message **curr_msg)
 852 {
 853         enum lttng_live_iterator_status live_status =
 854                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 855         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 856         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 857         /*
 858          * The viewer has hung up on us so we are closing the stream. The
 859          * `ctf_msg_iter` should simply realize that it needs to close the
 860          * stream properly by emitting the necessary stream end message.
 861          */
 862         enum ctf_msg_iter_status status = ctf_msg_iter_get_next_message(
 863                 stream_iter->msg_iter, curr_msg);
 864
 865         if (status == CTF_MSG_ITER_STATUS_ERROR) {
 866                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 867                         "Error getting the next message from CTF message iterator");
 868                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 869                 goto end;
 870         }
 871
 872         BT_ASSERT(status == CTF_MSG_ITER_STATUS_OK);
 873
 874 end:
 875         return live_status;
 876 }
 877
 878 /*
 879  * helper function:
 880  *            handle_no_data_streams()
 881  *              retry:
 882  *                - for each ACTIVE_NO_DATA stream:
 883  *                  - query relayd for stream data, or quiescence info.
 884  *                    - if need metadata, get metadata, goto retry.
 885  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 886  *                  - if quiescent, move to QUIESCENT streams
 887  *                  - if fetched data, move to ACTIVE_DATA streams
 888  *                (at this point each stream either has data, or is quiescent)
 889  *
 890  *
 891  * iterator_next:
 892  *            handle_new_streams_and_metadata()
 893  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 894  *                  - query relayd for metadata
 895  *
 896  *            call handle_active_no_data_streams()
 897  *
 898  *            handle_quiescent_streams()
 899  *                - if at least one stream is ACTIVE_DATA:
 900  *                  - peek stream event with lowest timestamp -> next_ts
 901  *                  - for each quiescent stream
 902  *                    - if next_ts >= quiescent end
 903  *                      - set state to ACTIVE_NO_DATA
 904  *                - else
 905  *                  - for each quiescent stream
 906  *                      - set state to ACTIVE_NO_DATA
 907  *
 908  *            call handle_active_no_data_streams()
 909  *
 910  *            handle_active_data_streams()
 911  *                - if at least one stream is ACTIVE_DATA:
 912  *                    - get stream event with lowest timestamp from heap
 913  *                    - make that stream event the current message.
 914  *                    - move this stream heap position to its next event
 915  *                      - if we need to fetch data from relayd, move
 916  *                        stream to ACTIVE_NO_DATA.
 917  *                    - return OK
 918  *                - return AGAIN
 919  *
 920  * end criterion: ctrl-c on client. If relayd exits or the session
 921  * closes on the relay daemon side, we keep on waiting for streams.
 922  * Eventually handle --end timestamp (also an end criterion).
 923  *
 924  * When disconnected from relayd: try to re-connect endlessly.
 925  */
 926 static
 927 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 928                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 929                 struct lttng_live_stream_iterator *stream_iter,
 930                 bt_message **curr_msg)
 931 {
 932         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 933         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 934         enum lttng_live_iterator_status live_status;
 935
 936         if (stream_iter->has_stream_hung_up) {
 937                 /*
 938                  * The stream has hung up and the stream was properly closed
 939                  * during the last call to the current function. Return _END
 940                  * status now so that this stream iterator is removed for the
 941                  * stream iterator list.
 942                  */
 943                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 944                 goto end;
 945         }
 946
 947 retry:
 948         print_stream_state(stream_iter);
 949         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 950                 lttng_live_msg_iter);
 951         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 952                 goto end;
 953         }
 954         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 955                 lttng_live_msg_iter, stream_iter);
 956
 957         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 958                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 959                         /*
 960                          * We overwrite `live_status` since `curr_msg` is
 961                          * likely set to a valid message in this function.
 962                          */
 963                         live_status = lttng_live_iterator_close_stream(
 964                                 lttng_live_msg_iter, stream_iter, curr_msg);
 965                 }
 966                 goto end;
 967         }
 968         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 969                 lttng_live_msg_iter, stream_iter, curr_msg);
 970         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 971                 BT_ASSERT(!*curr_msg);
 972                 goto end;
 973         }
 974         if (*curr_msg) {
 975                 goto end;
 976         }
 977         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 978                 lttng_live_msg_iter, stream_iter, curr_msg);
 979         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 980                 BT_ASSERT(!*curr_msg);
 981         }
 982
 983 end:
 984         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 985                 goto retry;
 986         }
 987
 988         return live_status;
 989 }
 990
 991 static
 992 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 993                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 994                 struct lttng_live_trace *live_trace,
 995                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 996 {
 997         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 998         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 999         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1000         enum lttng_live_iterator_status stream_iter_status;;
1001         int64_t youngest_candidate_msg_ts = INT64_MAX;
1002         uint64_t stream_iter_idx;
1003
1004         BT_ASSERT_DBG(live_trace);
1005         BT_ASSERT_DBG(live_trace->stream_iterators);
1006         /*
1007          * Update the current message of every stream iterators of this trace.
1008          * The current msg of every stream must have a timestamp equal or
1009          * larger than the last message returned by this iterator. We must
1010          * ensure monotonicity.
1011          */
1012         stream_iter_idx = 0;
1013         while (stream_iter_idx < live_trace->stream_iterators->len) {
1014                 bool stream_iter_is_ended = false;
1015                 struct lttng_live_stream_iterator *stream_iter =
1016                         g_ptr_array_index(live_trace->stream_iterators,
1017                                 stream_iter_idx);
1018
1019                 /*
1020                  * Find if there is are now current message for this stream
1021                  * iterator get it.
1022                  */
1023                 while (!stream_iter->current_msg) {
1024                         bt_message *msg = NULL;
1025                         int64_t curr_msg_ts_ns = INT64_MAX;
1026                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
1027                                 lttng_live_msg_iter, stream_iter, &msg);
1028
1029                         BT_COMP_LOGD("live stream iterator returned status :%s",
1030                                 lttng_live_iterator_status_string(stream_iter_status));
1031                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1032                                 stream_iter_is_ended = true;
1033                                 break;
1034                         }
1035
1036                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1037                                 goto end;
1038                         }
1039
1040                         BT_ASSERT_DBG(msg);
1041
1042                         /*
1043                          * Get the timestamp in nanoseconds from origin of this
1044                          * messsage.
1045                          */
1046                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
1047                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
1048                                 &curr_msg_ts_ns);
1049
1050                         /*
1051                          * Check if the message of the current live stream
1052                          * iterator occured at the exact same time or after the
1053                          * last message returned by this component's message
1054                          * iterator. If not, we return an error.
1055                          */
1056                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
1057                                 stream_iter->current_msg = msg;
1058                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
1059                         } else {
1060                                 /*
1061                                  * We received a message in the past. To ensure
1062                                  * monotonicity, we can't send it forward.
1063                                  */
1064                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1065                                         "Message's timestamp is less than "
1066                                         "lttng-live's message iterator's last "
1067                                         "returned timestamp: "
1068                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1069                                         "last-msg-ts=%" PRId64,
1070                                         lttng_live_msg_iter, curr_msg_ts_ns,
1071                                         lttng_live_msg_iter->last_msg_ts_ns);
1072                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1073                                 goto end;
1074                         }
1075                 }
1076
1077                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1078
1079                 if (!stream_iter_is_ended) {
1080                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1081                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1082                                 /*
1083                                  * Update the current best candidate message
1084                                  * for the stream iterator of this live trace
1085                                  * to be forwarded downstream.
1086                                  */
1087                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1088                                 youngest_candidate_stream_iter = stream_iter;
1089                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1090                                 /*
1091                                  * Order the messages in an arbitrary but
1092                                  * deterministic way.
1093                                  */
1094                                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1095                                 int ret = common_muxing_compare_messages(
1096                                         stream_iter->current_msg,
1097                                         youngest_candidate_stream_iter->current_msg);
1098                                 if (ret < 0) {
1099                                         /*
1100                                          * The `youngest_candidate_stream_iter->current_msg`
1101                                          * should go first. Update the next
1102                                          * iterator and the current timestamp.
1103                                          */
1104                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1105                                         youngest_candidate_stream_iter = stream_iter;
1106                                 } else if (ret == 0) {
1107                                         /*
1108                                          * Unable to pick which one should go
1109                                          * first.
1110                                          */
1111                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1112                                                 "stream-iter-addr=%p"
1113                                                 "stream-iter-addr=%p",
1114                                                 stream_iter,
1115                                                 youngest_candidate_stream_iter);
1116                                 }
1117                         }
1118
1119                         stream_iter_idx++;
1120                 } else {
1121                         /*
1122                          * The live stream iterator has ended. That
1123                          * iterator is removed from the array, but
1124                          * there is no need to increment
1125                          * stream_iter_idx as
1126                          * g_ptr_array_remove_index_fast replaces the
1127                          * removed element with the array's last
1128                          * element.
1129                          */
1130                         g_ptr_array_remove_index_fast(
1131                                 live_trace->stream_iterators,
1132                                 stream_iter_idx);
1133                 }
1134         }
1135
1136         if (youngest_candidate_stream_iter) {
1137                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1138                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1139         } else {
1140                 /*
1141                  * The only case where we don't have a candidate for this trace
1142                  * is if we reached the end of all the iterators.
1143                  */
1144                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1145                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1146         }
1147
1148 end:
1149         return stream_iter_status;
1150 }
1151
1152 static
1153 enum lttng_live_iterator_status next_stream_iterator_for_session(
1154                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1155                 struct lttng_live_session *session,
1156                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1157 {
1158         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1159         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1160         enum lttng_live_iterator_status stream_iter_status;
1161         uint64_t trace_idx = 0;
1162         int64_t youngest_candidate_msg_ts = INT64_MAX;
1163         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1164
1165         /*
1166          * Make sure we are attached to the session and look for new streams
1167          * and metadata.
1168          */
1169         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1170         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1171                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1172                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1173                 goto end;
1174         }
1175
1176         BT_ASSERT_DBG(session->traces);
1177
1178         while (trace_idx < session->traces->len) {
1179                 bool trace_is_ended = false;
1180                 struct lttng_live_stream_iterator *stream_iter;
1181                 struct lttng_live_trace *trace =
1182                         g_ptr_array_index(session->traces, trace_idx);
1183
1184                 stream_iter_status = next_stream_iterator_for_trace(
1185                         lttng_live_msg_iter, trace, &stream_iter);
1186                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1187                         /*
1188                          * All the live stream iterators for this trace are
1189                          * ENDed. Remove the trace from this session.
1190                          */
1191                         trace_is_ended = true;
1192                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1193                         goto end;
1194                 }
1195
1196                 if (!trace_is_ended) {
1197                         BT_ASSERT_DBG(stream_iter);
1198
1199                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1200                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1201                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1202                                 youngest_candidate_stream_iter = stream_iter;
1203                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1204                                 /*
1205                                  * Order the messages in an arbitrary but
1206                                  * deterministic way.
1207                                  */
1208                                 int ret = common_muxing_compare_messages(
1209                                         stream_iter->current_msg,
1210                                         youngest_candidate_stream_iter->current_msg);
1211                                 if (ret < 0) {
1212                                         /*
1213                                          * The `youngest_candidate_stream_iter->current_msg`
1214                                          * should go first. Update the next iterator
1215                                          * and the current timestamp.
1216                                          */
1217                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1218                                         youngest_candidate_stream_iter = stream_iter;
1219                                 } else if (ret == 0) {
1220                                         /* Unable to pick which one should go first. */
1221                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1222                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1223                                                 stream_iter, youngest_candidate_stream_iter);
1224                                 }
1225                         }
1226                         trace_idx++;
1227                 } else {
1228                         /*
1229                          * trace_idx is not incremented since
1230                          * g_ptr_array_remove_index_fast replaces the
1231                          * element at trace_idx with the array's last element.
1232                          */
1233                         g_ptr_array_remove_index_fast(session->traces,
1234                                 trace_idx);
1235                 }
1236         }
1237         if (youngest_candidate_stream_iter) {
1238                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1239                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1240         } else {
1241                 /*
1242                  * The only cases where we don't have a candidate for this
1243                  * trace is:
1244                  *  1. if we reached the end of all the iterators of all the
1245                  *  traces of this session,
1246                  *  2. if we never had live stream iterator in the first place.
1247                  *
1248                  * In either cases, we return END.
1249                  */
1250                 BT_ASSERT(session->traces->len == 0);
1251                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1252         }
1253 end:
1254         return stream_iter_status;
1255 }
1256
1257 static inline
1258 void put_messages(bt_message_array_const msgs, uint64_t count)
1259 {
1260         uint64_t i;
1261
1262         for (i = 0; i < count; i++) {
1263                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1264         }
1265 }
1266
1267 BT_HIDDEN
1268 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1269                 bt_self_message_iterator *self_msg_it,
1270                 bt_message_array_const msgs, uint64_t capacity,
1271                 uint64_t *count)
1272 {
1273         bt_component_class_message_iterator_next_method_status status;
1274         enum lttng_live_viewer_status viewer_status;
1275         struct lttng_live_msg_iter *lttng_live_msg_iter =
1276                 bt_self_message_iterator_get_data(self_msg_it);
1277         struct lttng_live_component *lttng_live =
1278                 lttng_live_msg_iter->lttng_live_comp;
1279         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1280         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1281         enum lttng_live_iterator_status stream_iter_status;
1282         uint64_t session_idx;
1283
1284         *count = 0;
1285
1286         BT_ASSERT_DBG(lttng_live_msg_iter);
1287
1288         if (G_UNLIKELY(lttng_live_msg_iter->was_interrupted)) {
1289                 /*
1290                  * The iterator was interrupted in a previous call to the
1291                  * `_next()` method. We currently do not support generating
1292                  * messages after such event. The babeltrace2 CLI should never
1293                  * be running the graph after being interrupted. So this check
1294                  * is to prevent other graph users from using this live
1295                  * iterator in an messed up internal state.
1296                  */
1297                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1298                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1299                         "Message iterator was interrupted during a previous call to the `next()` and currently does not support continuing after such event.");
1300                 goto end;
1301         }
1302
1303         /*
1304          * Clear all the invalid message reference that might be left over in
1305          * the output array.
1306          */
1307         memset(msgs, 0, capacity * sizeof(*msgs));
1308
1309         /*
1310          * If no session are exposed on the relay found at the url provided by
1311          * the user, session count will be 0. In this case, we return status
1312          * end to return gracefully.
1313          */
1314         if (lttng_live_msg_iter->sessions->len == 0) {
1315                 if (lttng_live->params.sess_not_found_act !=
1316                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1317                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1318                         goto end;
1319                 } else {
1320                         /*
1321                          * The are no more active session for this session
1322                          * name. Retry to create a viewer session for the
1323                          * requested session name.
1324                          */
1325                         viewer_status = lttng_live_create_viewer_session(lttng_live_msg_iter);
1326                         if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1327                                 if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
1328                                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1329                                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1330                                                 "Error creating LTTng live viewer session");
1331                                 } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
1332                                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1333                                 } else {
1334                                         bt_common_abort();
1335                                 }
1336                                 goto end;
1337                         }
1338                 }
1339         }
1340
1341         if (lttng_live_msg_iter->active_stream_iter == 0) {
1342                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1343         }
1344
1345         /*
1346          * Here the muxing of message is done.
1347          *
1348          * We need to iterate over all the streams of all the traces of all the
1349          * viewer sessions in order to get the message with the smallest
1350          * timestamp. In this case, a session is a viewer session and there is
1351          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1352          * kernel). Each viewer session can have multiple traces, for example,
1353          * 64bit UST viewer sessions could have multiple per-pid traces.
1354          *
1355          * We iterate over the streams of each traces to update and see what is
1356          * their next message's timestamp. From those timestamps, we select the
1357          * message with the smallest timestamp as the best candidate message
1358          * for that trace and do the same thing across all the sessions.
1359          *
1360          * We then compare the timestamp of best candidate message of all the
1361          * sessions to pick the message with the smallest timestamp and we
1362          * return it.
1363          */
1364         while (*count < capacity) {
1365                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1366                           *candidate_stream_iter = NULL;
1367                 int64_t youngest_msg_ts_ns = INT64_MAX;
1368
1369                 BT_ASSERT_DBG(lttng_live_msg_iter->sessions);
1370                 session_idx = 0;
1371                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1372                         struct lttng_live_session *session =
1373                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1374                                         session_idx);
1375
1376                         /* Find the best candidate message to send downstream. */
1377                         stream_iter_status = next_stream_iterator_for_session(
1378                                 lttng_live_msg_iter, session,
1379                                 &candidate_stream_iter);
1380
1381                         /* If we receive an END status, it means that either:
1382                          * - Those traces never had active streams (UST with no
1383                          *   data produced yet),
1384                          * - All live stream iterators have ENDed.*/
1385                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1386                                 if (session->closed && session->traces->len == 0) {
1387                                         /*
1388                                          * Remove the session from the list.
1389                                          * session_idx is not modified since
1390                                          * g_ptr_array_remove_index_fast
1391                                          * replaces the the removed element with
1392                                          * the array's last element.
1393                                          */
1394                                         g_ptr_array_remove_index_fast(
1395                                                 lttng_live_msg_iter->sessions,
1396                                                 session_idx);
1397                                 } else {
1398                                         session_idx++;
1399                                 }
1400                                 continue;
1401                         }
1402
1403                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1404                                 goto return_status;
1405                         }
1406
1407                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1408                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1409                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1410                                 youngest_stream_iter = candidate_stream_iter;
1411                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1412                                 /*
1413                                  * The currently selected message to be sent
1414                                  * downstream next has the exact same timestamp
1415                                  * that of the current candidate message. We
1416                                  * must break the tie in a predictable manner.
1417                                  */
1418                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1419                                 /*
1420                                  * Order the messages in an arbitrary but
1421                                  * deterministic way.
1422                                  */
1423                                 int ret = common_muxing_compare_messages(
1424                                         candidate_stream_iter->current_msg,
1425                                         youngest_stream_iter->current_msg);
1426                                 if (ret < 0) {
1427                                         /*
1428                                          * The `candidate_stream_iter->current_msg`
1429                                          * should go first. Update the next
1430                                          * iterator and the current timestamp.
1431                                          */
1432                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1433                                         youngest_stream_iter = candidate_stream_iter;
1434                                 } else if (ret == 0) {
1435                                         /* Unable to pick which one should go first. */
1436                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1437                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1438                                                 youngest_stream_iter, candidate_stream_iter);
1439                                 }
1440                         }
1441
1442                         session_idx++;
1443                 }
1444
1445                 if (!youngest_stream_iter) {
1446                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1447                         goto return_status;
1448                 }
1449
1450                 BT_ASSERT_DBG(youngest_stream_iter->current_msg);
1451                 /* Ensure monotonicity. */
1452                 BT_ASSERT_DBG(lttng_live_msg_iter->last_msg_ts_ns <=
1453                         youngest_stream_iter->current_msg_ts_ns);
1454
1455                 /*
1456                  * Insert the next message to the message batch. This will set
1457                  * stream iterator current messsage to NULL so that next time
1458                  * we fetch the next message of that stream iterator
1459                  */
1460                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1461                 (*count)++;
1462
1463                 /* Update the last timestamp in nanoseconds sent downstream. */
1464                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1465                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1466
1467                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1468         }
1469
1470 return_status:
1471         switch (stream_iter_status) {
1472         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1473         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1474                 /*
1475                  * If we gathered messages, return _OK even if the graph was
1476                  * interrupted. This allows for the components downstream to at
1477                  * least get the thoses messages. If the graph was indeed
1478                  * interrupted there should not be another _next() call as the
1479                  * application will tear down the graph. This component class
1480                  * doesn't support restarting after an interruption.
1481                  */
1482                 if (*count > 0) {
1483                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1484                 } else {
1485                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1486                 }
1487                 break;
1488         case LTTNG_LIVE_ITERATOR_STATUS_END:
1489                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1490                 break;
1491         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1492                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1493                         "Memory error preparing the next batch of messages: "
1494                         "live-iter-status=%s",
1495                         lttng_live_iterator_status_string(stream_iter_status));
1496                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1497                 break;
1498         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1499         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1500         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1501                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1502                         "Error preparing the next batch of messages: "
1503                         "live-iter-status=%s",
1504                         lttng_live_iterator_status_string(stream_iter_status));
1505
1506                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1507                 /* Put all existing messages on error. */
1508                 put_messages(msgs, *count);
1509                 break;
1510         default:
1511                 bt_common_abort();
1512         }
1513
1514 end:
1515         return status;
1516 }
1517
1518 static
1519 struct lttng_live_msg_iter *lttng_live_msg_iter_create(
1520                 struct lttng_live_component *lttng_live_comp,
1521                 bt_self_message_iterator *self_msg_it)
1522 {
1523         bt_self_component *self_comp = lttng_live_comp->self_comp;
1524         bt_logging_level log_level = lttng_live_comp->log_level;
1525
1526         struct lttng_live_msg_iter *lttng_live_msg_iter =
1527                 g_new0(struct lttng_live_msg_iter, 1);
1528         if (!lttng_live_msg_iter) {
1529                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1530                         "Failed to allocate lttng_live_msg_iter");
1531                 goto end;
1532         }
1533
1534         lttng_live_msg_iter->log_level = lttng_live_comp->log_level;
1535         lttng_live_msg_iter->self_comp = lttng_live_comp->self_comp;
1536         lttng_live_msg_iter->lttng_live_comp = lttng_live_comp;
1537         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1538
1539         lttng_live_msg_iter->active_stream_iter = 0;
1540         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1541         lttng_live_msg_iter->was_interrupted = false;
1542
1543         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1544                 (GDestroyNotify) lttng_live_destroy_session);
1545         BT_ASSERT(lttng_live_msg_iter->sessions);
1546
1547 end:
1548         return lttng_live_msg_iter;
1549
1550 }
1551
1552 BT_HIDDEN
1553 bt_component_class_message_iterator_initialize_method_status lttng_live_msg_iter_init(
1554                 bt_self_message_iterator *self_msg_it,
1555                 bt_self_message_iterator_configuration *config,
1556                 bt_self_component_source *self_comp_src,
1557                 bt_self_component_port_output *self_port)
1558 {
1559         bt_component_class_message_iterator_initialize_method_status status;
1560         bt_self_component *self_comp =
1561                 bt_self_component_source_as_self_component(self_comp_src);
1562         struct lttng_live_component *lttng_live;
1563         struct lttng_live_msg_iter *lttng_live_msg_iter;
1564         enum lttng_live_viewer_status viewer_status;
1565         bt_logging_level log_level;
1566
1567         BT_ASSERT(self_msg_it);
1568
1569         lttng_live = bt_self_component_get_data(self_comp);
1570         log_level = lttng_live->log_level;
1571         self_comp = lttng_live->self_comp;
1572
1573
1574         /* There can be only one downstream iterator at the same time. */
1575         BT_ASSERT(!lttng_live->has_msg_iter);
1576         lttng_live->has_msg_iter = true;
1577
1578         lttng_live_msg_iter = lttng_live_msg_iter_create(lttng_live,
1579                 self_msg_it);
1580         if (!lttng_live_msg_iter) {
1581                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1582                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1583                         "Failed to create lttng_live_msg_iter");
1584                 goto error;
1585         }
1586
1587          viewer_status = live_viewer_connection_create(self_comp, NULL,
1588                 log_level, lttng_live->params.url->str, false,
1589                 lttng_live_msg_iter, &lttng_live_msg_iter->viewer_connection);
1590         if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1591                 if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
1592                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1593                                 "Failed to create viewer connection");
1594                 } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
1595                         /*
1596                          * Interruption in the _iter_init() method is not
1597                          * supported. Return an error.
1598                          */
1599                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1600                                 "Interrupted while creating viewer connection");
1601                 }
1602                 goto error;
1603         }
1604
1605         viewer_status = lttng_live_create_viewer_session(lttng_live_msg_iter);
1606         if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1607                 if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
1608                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1609                                 "Failed to create viewer session");
1610                 } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
1611                         /*
1612                          * Interruption in the _iter_init() method is not
1613                          * supported. Return an error.
1614                          */
1615                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1616                                 "Interrupted when creating viewer session");
1617                 }
1618                 goto error;
1619         }
1620
1621         if (lttng_live_msg_iter->sessions->len == 0) {
1622                 switch (lttng_live->params.sess_not_found_act) {
1623                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1624                         BT_COMP_LOGI("Unable to connect to the requested live viewer session. Keep trying to connect because of "
1625                                 "%s=\"%s\" component parameter: url=\"%s\"",
1626                                 SESS_NOT_FOUND_ACTION_PARAM,
1627                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1628                                 lttng_live->params.url->str);
1629                         break;
1630                 case SESSION_NOT_FOUND_ACTION_FAIL:
1631                         BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1632                                 "Unable to connect to the requested live viewer session. Fail the message iterator initialization because of %s=\"%s\" "
1633                                 "component parameter: url =\"%s\"",
1634                                 SESS_NOT_FOUND_ACTION_PARAM,
1635                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1636                                 lttng_live->params.url->str);
1637                         goto error;
1638                 case SESSION_NOT_FOUND_ACTION_END:
1639                         BT_COMP_LOGI("Unable to connect to the requested live viewer session. End gracefully at the first _next() "
1640                                 "call because of %s=\"%s\" component parameter: "
1641                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1642                                 SESS_NOT_FOUND_ACTION_END_STR,
1643                                 lttng_live->params.url->str);
1644                         break;
1645                 default:
1646                         bt_common_abort();
1647                 }
1648         }
1649
1650         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1651         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_OK;
1652         goto end;
1653
1654 error:
1655         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1656         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1657 end:
1658         return status;
1659 }
1660
1661 static struct bt_param_validation_map_value_entry_descr list_sessions_params[] = {
1662         { URL_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { .type = BT_VALUE_TYPE_STRING } },
1663         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1664 };
1665
1666 static
1667 bt_component_class_query_method_status lttng_live_query_list_sessions(
1668                 const bt_value *params, const bt_value **result,
1669                 bt_self_component_class *self_comp_class,
1670                 bt_logging_level log_level)
1671 {
1672         bt_component_class_query_method_status status;
1673         const bt_value *url_value = NULL;
1674         const char *url;
1675         struct live_viewer_connection *viewer_connection = NULL;
1676         enum lttng_live_viewer_status viewer_status;
1677         enum bt_param_validation_status validation_status;
1678         gchar *validate_error = NULL;
1679
1680         validation_status = bt_param_validation_validate(params,
1681                 list_sessions_params, &validate_error);
1682         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1683                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1684                 goto error;
1685         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1686                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1687                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class, "%s",
1688                         validate_error);
1689                 goto error;
1690         }
1691
1692         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1693         url = bt_value_string_get(url_value);
1694
1695         viewer_status = live_viewer_connection_create(NULL, self_comp_class,
1696                 log_level, url, true, NULL, &viewer_connection);
1697         if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1698                 if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
1699                         BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1700                                 "Failed to create viewer connection");
1701                         status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1702                 } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
1703                         status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_AGAIN;
1704                 } else {
1705                         bt_common_abort();
1706                 }
1707                 goto error;
1708         }
1709
1710         status = live_viewer_connection_list_sessions(viewer_connection,
1711                 result);
1712         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1713                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1714                         "Failed to list viewer sessions");
1715                 goto error;
1716         }
1717
1718         goto end;
1719
1720 error:
1721         BT_VALUE_PUT_REF_AND_RESET(*result);
1722
1723         if (status >= 0) {
1724                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1725         }
1726
1727 end:
1728         if (viewer_connection) {
1729                 live_viewer_connection_destroy(viewer_connection);
1730         }
1731
1732         g_free(validate_error);
1733
1734         return status;
1735 }
1736
1737 static
1738 bt_component_class_query_method_status lttng_live_query_support_info(
1739                 const bt_value *params, const bt_value **result,
1740                 bt_self_component_class *self_comp_class,
1741                 bt_logging_level log_level)
1742 {
1743         bt_component_class_query_method_status status =
1744                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1745         const bt_value *input_type_value;
1746         const bt_value *input_value;
1747         double weight = 0;
1748         struct bt_common_lttng_live_url_parts parts = { 0 };
1749
1750         /* Used by the logging macros */
1751         __attribute__((unused)) bt_self_component *self_comp = NULL;
1752
1753         *result = NULL;
1754         input_type_value = bt_value_map_borrow_entry_value_const(params,
1755                 "type");
1756         if (!input_type_value) {
1757                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1758                         "Missing expected `type` parameter.");
1759                 goto error;
1760         }
1761
1762         if (!bt_value_is_string(input_type_value)) {
1763                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1764                         "`type` parameter is not a string value.");
1765                 goto error;
1766         }
1767
1768         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1769                 /* We don't handle file system paths */
1770                 goto create_result;
1771         }
1772
1773         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1774         if (!input_value) {
1775                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1776                         "Missing expected `input` parameter.");
1777                 goto error;
1778         }
1779
1780         if (!bt_value_is_string(input_value)) {
1781                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1782                         "`input` parameter is not a string value.");
1783                 goto error;
1784         }
1785
1786         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1787                 NULL, 0);
1788         if (parts.session_name) {
1789                 /*
1790                  * Looks pretty much like an LTTng live URL: we got the
1791                  * session name part, which forms a complete URL.
1792                  */
1793                 weight = .75;
1794         }
1795
1796 create_result:
1797         *result = bt_value_real_create_init(weight);
1798         if (!*result) {
1799                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1800                 goto error;
1801         }
1802
1803         goto end;
1804
1805 error:
1806         if (status >= 0) {
1807                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1808         }
1809
1810         BT_ASSERT(!*result);
1811
1812 end:
1813         bt_common_destroy_lttng_live_url_parts(&parts);
1814         return status;
1815 }
1816
1817 BT_HIDDEN
1818 bt_component_class_query_method_status lttng_live_query(
1819                 bt_self_component_class_source *comp_class,
1820                 bt_private_query_executor *priv_query_exec,
1821                 const char *object, const bt_value *params,
1822                 __attribute__((unused)) void *method_data,
1823                 const bt_value **result)
1824 {
1825         bt_component_class_query_method_status status =
1826                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1827         bt_self_component *self_comp = NULL;
1828         bt_self_component_class *self_comp_class =
1829                 bt_self_component_class_source_as_self_component_class(comp_class);
1830         bt_logging_level log_level = bt_query_executor_get_logging_level(
1831                 bt_private_query_executor_as_query_executor_const(
1832                         priv_query_exec));
1833
1834         if (strcmp(object, "sessions") == 0) {
1835                 status = lttng_live_query_list_sessions(params, result,
1836                         self_comp_class, log_level);
1837         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1838                 status = lttng_live_query_support_info(params, result,
1839                         self_comp_class, log_level);
1840         } else {
1841                 BT_COMP_LOGI("Unknown query object `%s`", object);
1842                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1843                 goto end;
1844         }
1845
1846 end:
1847         return status;
1848 }
1849
1850 static
1851 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1852 {
1853         if (!lttng_live) {
1854                 return;
1855         }
1856         if (lttng_live->params.url) {
1857                 g_string_free(lttng_live->params.url, TRUE);
1858         }
1859         g_free(lttng_live);
1860 }
1861
1862 BT_HIDDEN
1863 void lttng_live_component_finalize(bt_self_component_source *component)
1864 {
1865         void *data = bt_self_component_get_data(
1866                 bt_self_component_source_as_self_component(component));
1867
1868         if (!data) {
1869                 return;
1870         }
1871         lttng_live_component_destroy_data(data);
1872 }
1873
1874 static
1875 enum session_not_found_action parse_session_not_found_action_param(
1876         const bt_value *no_session_param)
1877 {
1878         enum session_not_found_action action;
1879         const char *no_session_act_str = bt_value_string_get(no_session_param);
1880
1881         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1882                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1883         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1884                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1885         } else {
1886                 BT_ASSERT(strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0);
1887                 action = SESSION_NOT_FOUND_ACTION_END;
1888         }
1889
1890         return action;
1891 }
1892
1893 static struct bt_param_validation_value_descr inputs_elem_descr = {
1894         .type = BT_VALUE_TYPE_STRING,
1895 };
1896
1897 static const char *sess_not_found_action_choices[] = {
1898         SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1899         SESS_NOT_FOUND_ACTION_FAIL_STR,
1900         SESS_NOT_FOUND_ACTION_END_STR,
1901 };
1902
1903 static struct bt_param_validation_map_value_entry_descr params_descr[] = {
1904         { INPUTS_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { BT_VALUE_TYPE_ARRAY, .array = {
1905                 .min_length = 1,
1906                 .max_length = 1,
1907                 .element_type = &inputs_elem_descr,
1908         } } },
1909         { SESS_NOT_FOUND_ACTION_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL, { BT_VALUE_TYPE_STRING, .string = {
1910                 .choices = sess_not_found_action_choices,
1911         } } },
1912         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1913 };
1914
1915 static
1916 bt_component_class_initialize_method_status lttng_live_component_create(
1917                 const bt_value *params,
1918                 bt_logging_level log_level,
1919                 bt_self_component *self_comp,
1920                 struct lttng_live_component **component)
1921 {
1922         struct lttng_live_component *lttng_live = NULL;
1923         const bt_value *inputs_value;
1924         const bt_value *url_value;
1925         const bt_value *value;
1926         const char *url;
1927         enum bt_param_validation_status validation_status;
1928         gchar *validation_error = NULL;
1929         bt_component_class_initialize_method_status status;
1930
1931         validation_status = bt_param_validation_validate(params, params_descr,
1932                 &validation_error);
1933         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1934                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1935                 goto error;
1936         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1937                 BT_COMP_LOGE_APPEND_CAUSE(self_comp, "%s", validation_error);
1938                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
1939                 goto error;
1940         }
1941
1942         lttng_live = g_new0(struct lttng_live_component, 1);
1943         if (!lttng_live) {
1944                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1945                 goto end;
1946         }
1947         lttng_live->log_level = log_level;
1948         lttng_live->self_comp = self_comp;
1949         lttng_live->max_query_size = MAX_QUERY_SIZE;
1950         lttng_live->has_msg_iter = false;
1951
1952         inputs_value =
1953                 bt_value_map_borrow_entry_value_const(params, INPUTS_PARAM);
1954         url_value =
1955                 bt_value_array_borrow_element_by_index_const(inputs_value, 0);
1956         url = bt_value_string_get(url_value);
1957
1958         lttng_live->params.url = g_string_new(url);
1959         if (!lttng_live->params.url) {
1960                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1961                 goto error;
1962         }
1963
1964         value = bt_value_map_borrow_entry_value_const(params,
1965                 SESS_NOT_FOUND_ACTION_PARAM);
1966         if (value) {
1967                 lttng_live->params.sess_not_found_act =
1968                         parse_session_not_found_action_param(value);
1969         } else {
1970                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1971                         "defaulting to `%s`.",
1972                         SESS_NOT_FOUND_ACTION_PARAM,
1973                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1974                 lttng_live->params.sess_not_found_act =
1975                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1976         }
1977
1978         status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;
1979         goto end;
1980
1981 error:
1982         lttng_live_component_destroy_data(lttng_live);
1983         lttng_live = NULL;
1984 end:
1985         g_free(validation_error);
1986
1987         *component = lttng_live;
1988         return status;
1989 }
1990
1991 BT_HIDDEN
1992 bt_component_class_initialize_method_status lttng_live_component_init(
1993                 bt_self_component_source *self_comp_src,
1994                 bt_self_component_source_configuration *config,
1995                 const bt_value *params,
1996                 __attribute__((unused)) void *init_method_data)
1997 {
1998         struct lttng_live_component *lttng_live;
1999         bt_component_class_initialize_method_status ret;
2000         bt_self_component *self_comp =
2001                 bt_self_component_source_as_self_component(self_comp_src);
2002         bt_logging_level log_level = bt_component_get_logging_level(
2003                 bt_self_component_as_component(self_comp));
2004         bt_self_component_add_port_status add_port_status;
2005
2006         ret = lttng_live_component_create(params, log_level, self_comp, &lttng_live);
2007         if (ret != BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK) {
2008                 goto error;
2009         }
2010
2011         add_port_status = bt_self_component_source_add_output_port(
2012                 self_comp_src, "out", NULL, NULL);
2013         if (add_port_status != BT_SELF_COMPONENT_ADD_PORT_STATUS_OK) {
2014                 ret = (int) add_port_status;
2015                 goto end;
2016         }
2017
2018         bt_self_component_set_data(self_comp, lttng_live);
2019         goto end;
2020
2021 error:
2022         lttng_live_component_destroy_data(lttng_live);
2023         lttng_live = NULL;
2024 end:
2025         return ret;
2026 }