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