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

   1 /*
   2  * lttng-live.c
   3  *
   4  * Babeltrace CTF LTTng-live Client Component
   5  *
   6  * Copyright 2019 Francis Deslauriers <francis.deslauriers@efficios.com>
   7  * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8  * Copyright 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a copy
  13  * of this software and associated documentation files (the "Software"), to deal
  14  * in the Software without restriction, including without limitation the rights
  15  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  16  * copies of the Software, and to permit persons to whom the Software is
  17  * furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included in
  20  * all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  27  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  28  * SOFTWARE.
  29  */
  30
  31 #define BT_COMP_LOG_SELF_COMP self_comp
  32 #define BT_LOG_OUTPUT_LEVEL log_level
  33 #define BT_LOG_TAG "PLUGIN/SRC.CTF.LTTNG-LIVE"
  34 #include "logging/comp-logging.h"
  35
  36 #include <glib.h>
  37 #include <inttypes.h>
  38 #include <stdbool.h>
  39 #include <unistd.h>
  40
  41 #include "common/assert.h"
  42 #include <babeltrace2/babeltrace.h>
  43 #include "compat/compiler.h"
  44 #include <babeltrace2/types.h>
  45
  46 #include "plugins/common/muxing/muxing.h"
  47 #include "plugins/common/param-validation/param-validation.h"
  48
  49 #include "data-stream.h"
  50 #include "metadata.h"
  51 #include "lttng-live.h"
  52
  53 #define MAX_QUERY_SIZE                      (256*1024)
  54 #define URL_PARAM                           "url"
  55 #define INPUTS_PARAM                        "inputs"
  56 #define SESS_NOT_FOUND_ACTION_PARAM         "session-not-found-action"
  57 #define SESS_NOT_FOUND_ACTION_CONTINUE_STR  "continue"
  58 #define SESS_NOT_FOUND_ACTION_FAIL_STR      "fail"
  59 #define SESS_NOT_FOUND_ACTION_END_STR       "end"
  60
  61 #define print_dbg(fmt, ...)     BT_COMP_LOGD(fmt, ## __VA_ARGS__)
  62
  63 static
  64 const char *print_live_iterator_status(enum lttng_live_iterator_status status)
  65 {
  66         switch (status) {
  67         case LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
  68                 return "LTTNG_LIVE_ITERATOR_STATUS_CONTINUE";
  69         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
  70                 return "LTTNG_LIVE_ITERATOR_STATUS_AGAIN";
  71         case LTTNG_LIVE_ITERATOR_STATUS_END:
  72                 return "LTTNG_LIVE_ITERATOR_STATUS_END";
  73         case LTTNG_LIVE_ITERATOR_STATUS_OK:
  74                 return "LTTNG_LIVE_ITERATOR_STATUS_OK";
  75         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
  76                 return "LTTNG_LIVE_ITERATOR_STATUS_INVAL";
  77         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
  78                 return "LTTNG_LIVE_ITERATOR_STATUS_ERROR";
  79         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
  80                 return "LTTNG_LIVE_ITERATOR_STATUS_NOMEM";
  81         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
  82                 return "LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED";
  83         default:
  84                 abort();
  85         }
  86 }
  87
  88 static
  89 const char *print_state(struct lttng_live_stream_iterator *s)
  90 {
  91         switch (s->state) {
  92         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
  93                 return "ACTIVE_NO_DATA";
  94         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
  95                 return "QUIESCENT_NO_DATA";
  96         case LTTNG_LIVE_STREAM_QUIESCENT:
  97                 return "QUIESCENT";
  98         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
  99                 return "ACTIVE_DATA";
 100         case LTTNG_LIVE_STREAM_EOF:
 101                 return "EOF";
 102         default:
 103                 return "ERROR";
 104         }
 105 }
 106
 107 #define print_stream_state(live_stream_iter) \
 108         do { \
 109                 BT_COMP_LOGD("stream state %s last_inact_ts %" PRId64  \
 110                         ", curr_inact_ts %" PRId64, \
 111                         print_state(live_stream_iter), \
 112                         live_stream_iter->last_inactivity_ts, \
 113                         live_stream_iter->current_inactivity_ts); \
 114         } while (0);
 115
 116 BT_HIDDEN
 117 bool lttng_live_graph_is_canceled(struct lttng_live_msg_iter *msg_iter)
 118 {
 119         bool ret;
 120
 121         if (!msg_iter) {
 122                 ret = false;
 123                 goto end;
 124         }
 125
 126         ret = bt_self_message_iterator_is_interrupted(
 127                 msg_iter->self_msg_iter);
 128
 129 end:
 130         return ret;
 131 }
 132
 133 static
 134 struct lttng_live_trace *lttng_live_find_trace(struct lttng_live_session *session,
 135                 uint64_t trace_id)
 136 {
 137         uint64_t trace_idx;
 138         struct lttng_live_trace *ret_trace = NULL;
 139
 140         for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
 141                 struct lttng_live_trace *trace =
 142                         g_ptr_array_index(session->traces, trace_idx);
 143                 if (trace->id == trace_id) {
 144                         ret_trace = trace;
 145                         goto end;
 146                 }
 147         }
 148
 149 end:
 150         return ret_trace;
 151 }
 152
 153 static
 154 void lttng_live_destroy_trace(struct lttng_live_trace *trace)
 155 {
 156         bt_logging_level log_level = trace->log_level;
 157         bt_self_component *self_comp = trace->self_comp;
 158
 159         BT_COMP_LOGD("Destroy lttng_live_trace");
 160
 161         BT_ASSERT(trace->stream_iterators);
 162         g_ptr_array_free(trace->stream_iterators, TRUE);
 163
 164         BT_TRACE_PUT_REF_AND_RESET(trace->trace);
 165         BT_TRACE_CLASS_PUT_REF_AND_RESET(trace->trace_class);
 166
 167         lttng_live_metadata_fini(trace);
 168         g_free(trace);
 169 }
 170
 171 static
 172 struct lttng_live_trace *lttng_live_create_trace(struct lttng_live_session *session,
 173                 uint64_t trace_id)
 174 {
 175         struct lttng_live_trace *trace = NULL;
 176         bt_logging_level log_level = session->log_level;
 177         bt_self_component *self_comp = session->self_comp;
 178
 179         trace = g_new0(struct lttng_live_trace, 1);
 180         if (!trace) {
 181                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 182                         "Failed to allocate live trace");
 183                 goto error;
 184         }
 185         trace->log_level = session->log_level;
 186         trace->self_comp = session->self_comp;
 187         trace->session = session;
 188         trace->id = trace_id;
 189         trace->trace_class = NULL;
 190         trace->trace = NULL;
 191         trace->stream_iterators = g_ptr_array_new_with_free_func(
 192                 (GDestroyNotify) lttng_live_stream_iterator_destroy);
 193         BT_ASSERT(trace->stream_iterators);
 194         trace->new_metadata_needed = true;
 195         g_ptr_array_add(session->traces, trace);
 196
 197         BT_COMP_LOGI("Create trace");
 198         goto end;
 199 error:
 200         g_free(trace);
 201         trace = NULL;
 202 end:
 203         return trace;
 204 }
 205
 206 BT_HIDDEN
 207 struct lttng_live_trace *lttng_live_borrow_trace(
 208                 struct lttng_live_session *session, uint64_t trace_id)
 209 {
 210         struct lttng_live_trace *trace;
 211
 212         trace = lttng_live_find_trace(session, trace_id);
 213         if (trace) {
 214                 goto end;
 215         }
 216
 217         /* The session is the owner of the newly created trace. */
 218         trace = lttng_live_create_trace(session, trace_id);
 219
 220 end:
 221         return trace;
 222 }
 223
 224 BT_HIDDEN
 225 int lttng_live_add_session(struct lttng_live_msg_iter *lttng_live_msg_iter,
 226                 uint64_t session_id, const char *hostname,
 227                 const char *session_name)
 228 {
 229         int ret = 0;
 230         struct lttng_live_session *session;
 231         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 232         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 233
 234         session = g_new0(struct lttng_live_session, 1);
 235         if (!session) {
 236                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 237                         "Failed to allocate live session");
 238                 goto error;
 239         }
 240
 241         session->log_level = lttng_live_msg_iter->log_level;
 242         session->self_comp = lttng_live_msg_iter->self_comp;
 243         session->id = session_id;
 244         session->traces = g_ptr_array_new_with_free_func(
 245                 (GDestroyNotify) lttng_live_destroy_trace);
 246         BT_ASSERT(session->traces);
 247         session->lttng_live_msg_iter = lttng_live_msg_iter;
 248         session->new_streams_needed = true;
 249         session->hostname = g_string_new(hostname);
 250         BT_ASSERT(session->hostname);
 251
 252         session->session_name = g_string_new(session_name);
 253         BT_ASSERT(session->session_name);
 254
 255         BT_COMP_LOGI("Reading from session: %" PRIu64 " hostname: %s session_name: %s",
 256                 session->id, hostname, session_name);
 257         g_ptr_array_add(lttng_live_msg_iter->sessions, session);
 258         goto end;
 259 error:
 260         BT_COMP_LOGE_APPEND_CAUSE(self_comp, "Error adding session");
 261         g_free(session);
 262         ret = -1;
 263 end:
 264         return ret;
 265 }
 266
 267 static
 268 void lttng_live_destroy_session(struct lttng_live_session *session)
 269 {
 270         bt_logging_level log_level;
 271         bt_self_component *self_comp;
 272
 273         if (!session) {
 274                 goto end;
 275         }
 276
 277         log_level = session->log_level;
 278         self_comp = session->self_comp;
 279         BT_COMP_LOGD("Destroy lttng live session");
 280         if (session->id != -1ULL) {
 281                 if (lttng_live_detach_session(session)) {
 282                         if (!lttng_live_graph_is_canceled(
 283                                         session->lttng_live_msg_iter)) {
 284                                 /* Old relayd cannot detach sessions. */
 285                                 BT_COMP_LOGD("Unable to detach lttng live session %" PRIu64,
 286                                         session->id);
 287                         }
 288                 }
 289                 session->id = -1ULL;
 290         }
 291
 292         if (session->traces) {
 293                 g_ptr_array_free(session->traces, TRUE);
 294         }
 295
 296         if (session->hostname) {
 297                 g_string_free(session->hostname, TRUE);
 298         }
 299         if (session->session_name) {
 300                 g_string_free(session->session_name, TRUE);
 301         }
 302         g_free(session);
 303
 304 end:
 305         return;
 306 }
 307
 308 static
 309 void lttng_live_msg_iter_destroy(struct lttng_live_msg_iter *lttng_live_msg_iter)
 310 {
 311         if (!lttng_live_msg_iter) {
 312                 goto end;
 313         }
 314
 315         if (lttng_live_msg_iter->sessions) {
 316                 g_ptr_array_free(lttng_live_msg_iter->sessions, TRUE);
 317         }
 318
 319         if (lttng_live_msg_iter->viewer_connection) {
 320                 live_viewer_connection_destroy(lttng_live_msg_iter->viewer_connection);
 321         }
 322         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp);
 323         BT_ASSERT(lttng_live_msg_iter->lttng_live_comp->has_msg_iter);
 324
 325         /* All stream iterators must be destroyed at this point. */
 326         BT_ASSERT(lttng_live_msg_iter->active_stream_iter == 0);
 327         lttng_live_msg_iter->lttng_live_comp->has_msg_iter = false;
 328
 329         g_free(lttng_live_msg_iter);
 330
 331 end:
 332         return;
 333 }
 334
 335 BT_HIDDEN
 336 void lttng_live_msg_iter_finalize(bt_self_message_iterator *self_msg_iter)
 337 {
 338         struct lttng_live_msg_iter *lttng_live_msg_iter;
 339
 340         BT_ASSERT(self_msg_iter);
 341
 342         lttng_live_msg_iter = bt_self_message_iterator_get_data(self_msg_iter);
 343         BT_ASSERT(lttng_live_msg_iter);
 344         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
 345 }
 346
 347 static
 348 enum lttng_live_iterator_status lttng_live_iterator_next_check_stream_state(
 349                 struct lttng_live_stream_iterator *lttng_live_stream)
 350 {
 351         bt_logging_level log_level = lttng_live_stream->log_level;
 352         bt_self_component *self_comp = lttng_live_stream->self_comp;
 353
 354         switch (lttng_live_stream->state) {
 355         case LTTNG_LIVE_STREAM_QUIESCENT:
 356         case LTTNG_LIVE_STREAM_ACTIVE_DATA:
 357                 break;
 358         case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
 359                 /* Invalid state. */
 360                 BT_COMP_LOGF("Unexpected stream state \"ACTIVE_NO_DATA\"");
 361                 abort();
 362         case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
 363                 /* Invalid state. */
 364                 BT_COMP_LOGF("Unexpected stream state \"QUIESCENT_NO_DATA\"");
 365                 abort();
 366         case LTTNG_LIVE_STREAM_EOF:
 367                 break;
 368         }
 369         return LTTNG_LIVE_ITERATOR_STATUS_OK;
 370 }
 371
 372 /*
 373  * For active no data stream, fetch next data. It can be either:
 374  * - quiescent: need to put it in the prio heap at quiescent end
 375  *   timestamp,
 376  * - have data: need to wire up first event into the prio heap,
 377  * - have no data on this stream at this point: need to retry (AGAIN) or
 378  *   return EOF.
 379  */
 380 static
 381 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_no_data_stream(
 382                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 383                 struct lttng_live_stream_iterator *lttng_live_stream)
 384 {
 385         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 386         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 387         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 388         enum lttng_live_stream_state orig_state = lttng_live_stream->state;
 389         struct packet_index index;
 390
 391         if (lttng_live_stream->trace->new_metadata_needed) {
 392                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 393                 goto end;
 394         }
 395         if (lttng_live_stream->trace->session->new_streams_needed) {
 396                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 397                 goto end;
 398         }
 399         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_NO_DATA &&
 400                         lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA) {
 401                 goto end;
 402         }
 403         ret = lttng_live_get_next_index(lttng_live_msg_iter, lttng_live_stream,
 404                 &index);
 405         if (ret != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 406                 goto end;
 407         }
 408         BT_ASSERT_DBG(lttng_live_stream->state != LTTNG_LIVE_STREAM_EOF);
 409         if (lttng_live_stream->state == LTTNG_LIVE_STREAM_QUIESCENT) {
 410                 uint64_t last_inact_ts = lttng_live_stream->last_inactivity_ts,
 411                          curr_inact_ts = lttng_live_stream->current_inactivity_ts;
 412
 413                 if (orig_state == LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA &&
 414                                 last_inact_ts == curr_inact_ts) {
 415                         ret = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 416                         print_stream_state(lttng_live_stream);
 417                 } else {
 418                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 419                 }
 420                 goto end;
 421         }
 422         lttng_live_stream->base_offset = index.offset;
 423         lttng_live_stream->offset = index.offset;
 424         lttng_live_stream->len = index.packet_size / CHAR_BIT;
 425 end:
 426         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK) {
 427                 ret = lttng_live_iterator_next_check_stream_state(lttng_live_stream);
 428         }
 429         return ret;
 430 }
 431
 432 /*
 433  * Creation of the message requires the ctf trace class to be created
 434  * beforehand, but the live protocol gives us all streams (including metadata)
 435  * at once. So we split it in three steps: getting streams, getting metadata
 436  * (which creates the ctf trace class), and then creating the per-stream
 437  * messages.
 438  */
 439 static
 440 enum lttng_live_iterator_status lttng_live_get_session(
 441                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 442                 struct lttng_live_session *session)
 443 {
 444         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 445         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 446         enum lttng_live_iterator_status status;
 447         uint64_t trace_idx;
 448
 449         if (!session->attached) {
 450                 enum lttng_live_attach_session_status attach_status =
 451                         lttng_live_attach_session(session);
 452                 if (attach_status != LTTNG_LIVE_ATTACH_SESSION_STATUS_OK) {
 453                         if (lttng_live_graph_is_canceled(lttng_live_msg_iter)) {
 454                                 /*
 455                                  * Clear any causes appended in
 456                                  * `lttng_live_attach_session()` as we want to
 457                                  * return gracefully since the graph was
 458                                  * cancelled.
 459                                  */
 460                                 bt_current_thread_clear_error();
 461                                 status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
 462                         } else {
 463                                 status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 464                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 465                                         "Error attaching to LTTng live session");
 466                         }
 467                         goto end;
 468                 }
 469         }
 470
 471         status = lttng_live_get_new_streams(session);
 472         if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
 473                         status != LTTNG_LIVE_ITERATOR_STATUS_END) {
 474                 goto end;
 475         }
 476         trace_idx = 0;
 477         while (trace_idx < session->traces->len) {
 478                 struct lttng_live_trace *trace =
 479                         g_ptr_array_index(session->traces, trace_idx);
 480
 481                 status = lttng_live_metadata_update(trace);
 482                 switch (status) {
 483                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 484                         trace_idx++;
 485                         break;
 486                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 487                         /*
 488                          * The trace has ended. Remove it of the array an
 489                          * continue the iteration.
 490                          * We can remove the trace safely when using the
 491                          * g_ptr_array_remove_index_fast because it replaces
 492                          * the element at trace_idx with the array's last
 493                          * element. trace_idx is not incremented because of
 494                          * that.
 495                          */
 496                         (void) g_ptr_array_remove_index_fast(session->traces,
 497                                 trace_idx);
 498                         break;
 499                 default:
 500                         goto end;
 501                 }
 502         }
 503         status = lttng_live_lazy_msg_init(session);
 504
 505 end:
 506         return status;
 507 }
 508
 509 BT_HIDDEN
 510 void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
 511 {
 512         uint64_t session_idx;
 513
 514         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 515                         session_idx++) {
 516                 struct lttng_live_session *session =
 517                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 518                 session->new_streams_needed = true;
 519         }
 520 }
 521
 522 static
 523 void lttng_live_force_new_streams_and_metadata(struct lttng_live_msg_iter *lttng_live_msg_iter)
 524 {
 525         uint64_t session_idx, trace_idx;
 526
 527         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 528                         session_idx++) {
 529                 struct lttng_live_session *session =
 530                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 531                 session->new_streams_needed = true;
 532                 for (trace_idx = 0; trace_idx < session->traces->len;
 533                                 trace_idx++) {
 534                         struct lttng_live_trace *trace =
 535                                 g_ptr_array_index(session->traces, trace_idx);
 536                         trace->new_metadata_needed = true;
 537                 }
 538         }
 539 }
 540
 541 static
 542 enum lttng_live_iterator_status
 543 lttng_live_iterator_handle_new_streams_and_metadata(
 544                 struct lttng_live_msg_iter *lttng_live_msg_iter)
 545 {
 546         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 547         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 548         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 549         uint64_t session_idx = 0, nr_sessions_opened = 0;
 550         struct lttng_live_session *session;
 551         enum session_not_found_action sess_not_found_act =
 552                 lttng_live_msg_iter->lttng_live_comp->params.sess_not_found_act;
 553
 554         /*
 555          * In a remotely distant future, we could add a "new
 556          * session" flag to the protocol, which would tell us that we
 557          * need to query for new sessions even though we have sessions
 558          * currently ongoing.
 559          */
 560         if (lttng_live_msg_iter->sessions->len == 0) {
 561                 if (sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE) {
 562                         ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 563                         goto end;
 564                 } else {
 565                         /*
 566                          * Retry to create a viewer session for the requested
 567                          * session name.
 568                          */
 569                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
 570                                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 571                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 572                                         "Error creating LTTng live viewer session");
 573                                 goto end;
 574                         }
 575                 }
 576         }
 577
 578         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 579                         session_idx++) {
 580                 session = g_ptr_array_index(lttng_live_msg_iter->sessions,
 581                                 session_idx);
 582                 ret = lttng_live_get_session(lttng_live_msg_iter, session);
 583                 switch (ret) {
 584                 case LTTNG_LIVE_ITERATOR_STATUS_OK:
 585                         break;
 586                 case LTTNG_LIVE_ITERATOR_STATUS_END:
 587                         ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 588                         break;
 589                 default:
 590                         goto end;
 591                 }
 592                 if (!session->closed) {
 593                         nr_sessions_opened++;
 594                 }
 595         }
 596 end:
 597         if (ret == LTTNG_LIVE_ITERATOR_STATUS_OK &&
 598                         sess_not_found_act != SESSION_NOT_FOUND_ACTION_CONTINUE &&
 599                         nr_sessions_opened == 0) {
 600                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 601         }
 602         return ret;
 603 }
 604
 605 static
 606 enum lttng_live_iterator_status emit_inactivity_message(
 607                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 608                 struct lttng_live_stream_iterator *stream_iter,
 609                 bt_message **message, uint64_t timestamp)
 610 {
 611         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 612         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 613         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 614         bt_message *msg = NULL;
 615
 616         BT_ASSERT(stream_iter->trace->clock_class);
 617
 618         msg = bt_message_message_iterator_inactivity_create(
 619                 lttng_live_msg_iter->self_msg_iter,
 620                 stream_iter->trace->clock_class, timestamp);
 621         if (!msg) {
 622                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 623                         "Error emitting message iterator inactivity message");
 624                 goto error;
 625         }
 626
 627         *message = msg;
 628 end:
 629         return ret;
 630
 631 error:
 632         ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 633         bt_message_put_ref(msg);
 634         goto end;
 635 }
 636
 637 static
 638 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
 639                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 640                 struct lttng_live_stream_iterator *lttng_live_stream,
 641                 bt_message **message)
 642 {
 643         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 644
 645         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
 646                 return LTTNG_LIVE_ITERATOR_STATUS_OK;
 647         }
 648
 649         if (lttng_live_stream->current_inactivity_ts ==
 650                         lttng_live_stream->last_inactivity_ts) {
 651                 lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
 652                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 653                 goto end;
 654         }
 655
 656         ret = emit_inactivity_message(lttng_live_msg_iter, lttng_live_stream,
 657                 message, lttng_live_stream->current_inactivity_ts);
 658
 659         lttng_live_stream->last_inactivity_ts =
 660                 lttng_live_stream->current_inactivity_ts;
 661 end:
 662         return ret;
 663 }
 664
 665 static
 666 int live_get_msg_ts_ns(struct lttng_live_stream_iterator *stream_iter,
 667                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 668                 const bt_message *msg, int64_t last_msg_ts_ns,
 669                 int64_t *ts_ns)
 670 {
 671         const bt_clock_class *clock_class = NULL;
 672         const bt_clock_snapshot *clock_snapshot = NULL;
 673         int ret = 0;
 674         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 675         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 676
 677         BT_ASSERT_DBG(msg);
 678         BT_ASSERT_DBG(ts_ns);
 679
 680         BT_COMP_LOGD("Getting message's timestamp: iter-data-addr=%p, msg-addr=%p, "
 681                 "last-msg-ts=%" PRId64, lttng_live_msg_iter, msg,
 682                 last_msg_ts_ns);
 683
 684         switch (bt_message_get_type(msg)) {
 685         case BT_MESSAGE_TYPE_EVENT:
 686                 clock_class = bt_message_event_borrow_stream_class_default_clock_class_const(
 687                                 msg);
 688                 BT_ASSERT_DBG(clock_class);
 689
 690                 clock_snapshot = bt_message_event_borrow_default_clock_snapshot_const(
 691                         msg);
 692                 break;
 693         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 694                 clock_class = bt_message_packet_beginning_borrow_stream_class_default_clock_class_const(
 695                         msg);
 696                 BT_ASSERT(clock_class);
 697
 698                 clock_snapshot = bt_message_packet_beginning_borrow_default_clock_snapshot_const(
 699                         msg);
 700                 break;
 701         case BT_MESSAGE_TYPE_PACKET_END:
 702                 clock_class = bt_message_packet_end_borrow_stream_class_default_clock_class_const(
 703                         msg);
 704                 BT_ASSERT(clock_class);
 705
 706                 clock_snapshot = bt_message_packet_end_borrow_default_clock_snapshot_const(
 707                         msg);
 708                 break;
 709         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 710                 clock_class = bt_message_discarded_events_borrow_stream_class_default_clock_class_const(
 711                         msg);
 712                 BT_ASSERT(clock_class);
 713
 714                 clock_snapshot = bt_message_discarded_events_borrow_beginning_default_clock_snapshot_const(
 715                         msg);
 716                 break;
 717         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 718                 clock_class = bt_message_discarded_packets_borrow_stream_class_default_clock_class_const(
 719                         msg);
 720                 BT_ASSERT(clock_class);
 721
 722                 clock_snapshot = bt_message_discarded_packets_borrow_beginning_default_clock_snapshot_const(
 723                         msg);
 724                 break;
 725         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 726                 clock_snapshot = bt_message_message_iterator_inactivity_borrow_default_clock_snapshot_const(
 727                         msg);
 728                 break;
 729         default:
 730                 /* All the other messages have a higher priority */
 731                 BT_COMP_LOGD_STR("Message has no timestamp: using the last message timestamp.");
 732                 *ts_ns = last_msg_ts_ns;
 733                 goto end;
 734         }
 735
 736         clock_class = bt_clock_snapshot_borrow_clock_class_const(clock_snapshot);
 737         BT_ASSERT_DBG(clock_class);
 738
 739         ret = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, ts_ns);
 740         if (ret) {
 741                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 742                         "Cannot get nanoseconds from Epoch of clock snapshot: "
 743                         "clock-snapshot-addr=%p", clock_snapshot);
 744                 goto error;
 745         }
 746
 747         goto end;
 748
 749 error:
 750         ret = -1;
 751
 752 end:
 753         if (ret == 0) {
 754                 BT_COMP_LOGD("Found message's timestamp: "
 755                         "iter-data-addr=%p, msg-addr=%p, "
 756                         "last-msg-ts=%" PRId64 ", ts=%" PRId64,
 757                         lttng_live_msg_iter, msg, last_msg_ts_ns, *ts_ns);
 758         }
 759
 760         return ret;
 761 }
 762
 763 static
 764 enum lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
 765                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 766                 struct lttng_live_stream_iterator *lttng_live_stream,
 767                 bt_message **message)
 768 {
 769         enum lttng_live_iterator_status ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 770         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 771         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 772         enum bt_msg_iter_status status;
 773         uint64_t session_idx, trace_idx;
 774
 775         for (session_idx = 0; session_idx < lttng_live_msg_iter->sessions->len;
 776                         session_idx++) {
 777                 struct lttng_live_session *session =
 778                         g_ptr_array_index(lttng_live_msg_iter->sessions, session_idx);
 779
 780                 if (session->new_streams_needed) {
 781                         ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 782                         goto end;
 783                 }
 784                 for (trace_idx = 0; trace_idx < session->traces->len;
 785                                 trace_idx++) {
 786                         struct lttng_live_trace *trace =
 787                                 g_ptr_array_index(session->traces, trace_idx);
 788                         if (trace->new_metadata_needed) {
 789                                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 790                                 goto end;
 791                         }
 792                 }
 793         }
 794
 795         if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
 796                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 797                 goto end;
 798         }
 799
 800         status = bt_msg_iter_get_next_message(lttng_live_stream->msg_iter,
 801                 lttng_live_msg_iter->self_msg_iter, message);
 802         switch (status) {
 803         case BT_MSG_ITER_STATUS_EOF:
 804                 ret = LTTNG_LIVE_ITERATOR_STATUS_END;
 805                 break;
 806         case BT_MSG_ITER_STATUS_OK:
 807                 ret = LTTNG_LIVE_ITERATOR_STATUS_OK;
 808                 break;
 809         case BT_MSG_ITER_STATUS_AGAIN:
 810                 /*
 811                  * Continue immediately (end of packet). The next
 812                  * get_index may return AGAIN to delay the following
 813                  * attempt.
 814                  */
 815                 ret = LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
 816                 break;
 817         case BT_MSG_ITER_STATUS_INVAL:
 818                 /* No argument provided by the user, so don't return INVAL. */
 819         case BT_MSG_ITER_STATUS_ERROR:
 820         default:
 821                 ret = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 822                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 823                         "CTF message iterator return an error or failed: "
 824                         "msg_iter=%p", lttng_live_stream->msg_iter);
 825                 break;
 826         }
 827
 828 end:
 829         return ret;
 830 }
 831
 832 static
 833 enum lttng_live_iterator_status lttng_live_iterator_close_stream(
 834                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 835                 struct lttng_live_stream_iterator *stream_iter,
 836                 bt_message **curr_msg)
 837 {
 838         enum lttng_live_iterator_status live_status =
 839                 LTTNG_LIVE_ITERATOR_STATUS_OK;
 840         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 841         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 842         /*
 843          * The viewer has hung up on us so we are closing the stream. The
 844          * `bt_msg_iter` should simply realize that it needs to close the
 845          * stream properly by emitting the necessary stream end message.
 846          */
 847         enum bt_msg_iter_status status = bt_msg_iter_get_next_message(
 848                 stream_iter->msg_iter, lttng_live_msg_iter->self_msg_iter,
 849                 curr_msg);
 850
 851         if (status == BT_MSG_ITER_STATUS_ERROR) {
 852                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
 853                         "Error getting the next message from CTF message iterator");
 854                 live_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
 855                 goto end;
 856         }
 857
 858         BT_ASSERT(status == BT_MSG_ITER_STATUS_OK);
 859
 860 end:
 861         return live_status;
 862 }
 863
 864 /*
 865  * helper function:
 866  *            handle_no_data_streams()
 867  *              retry:
 868  *                - for each ACTIVE_NO_DATA stream:
 869  *                  - query relayd for stream data, or quiescence info.
 870  *                    - if need metadata, get metadata, goto retry.
 871  *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
 872  *                  - if quiescent, move to QUIESCENT streams
 873  *                  - if fetched data, move to ACTIVE_DATA streams
 874  *                (at this point each stream either has data, or is quiescent)
 875  *
 876  *
 877  * iterator_next:
 878  *            handle_new_streams_and_metadata()
 879  *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
 880  *                  - query relayd for metadata
 881  *
 882  *            call handle_active_no_data_streams()
 883  *
 884  *            handle_quiescent_streams()
 885  *                - if at least one stream is ACTIVE_DATA:
 886  *                  - peek stream event with lowest timestamp -> next_ts
 887  *                  - for each quiescent stream
 888  *                    - if next_ts >= quiescent end
 889  *                      - set state to ACTIVE_NO_DATA
 890  *                - else
 891  *                  - for each quiescent stream
 892  *                      - set state to ACTIVE_NO_DATA
 893  *
 894  *            call handle_active_no_data_streams()
 895  *
 896  *            handle_active_data_streams()
 897  *                - if at least one stream is ACTIVE_DATA:
 898  *                    - get stream event with lowest timestamp from heap
 899  *                    - make that stream event the current message.
 900  *                    - move this stream heap position to its next event
 901  *                      - if we need to fetch data from relayd, move
 902  *                        stream to ACTIVE_NO_DATA.
 903  *                    - return OK
 904  *                - return AGAIN
 905  *
 906  * end criterion: ctrl-c on client. If relayd exits or the session
 907  * closes on the relay daemon side, we keep on waiting for streams.
 908  * Eventually handle --end timestamp (also an end criterion).
 909  *
 910  * When disconnected from relayd: try to re-connect endlessly.
 911  */
 912 static
 913 enum lttng_live_iterator_status lttng_live_iterator_next_msg_on_stream(
 914                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 915                 struct lttng_live_stream_iterator *stream_iter,
 916                 bt_message **curr_msg)
 917 {
 918         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 919         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 920         enum lttng_live_iterator_status live_status;
 921
 922         if (stream_iter->has_stream_hung_up) {
 923                 /*
 924                  * The stream has hung up and the stream was properly closed
 925                  * during the last call to the current function. Return _END
 926                  * status now so that this stream iterator is removed for the
 927                  * stream iterator list.
 928                  */
 929                 live_status = LTTNG_LIVE_ITERATOR_STATUS_END;
 930                 goto end;
 931         }
 932
 933 retry:
 934         print_stream_state(stream_iter);
 935         live_status = lttng_live_iterator_handle_new_streams_and_metadata(
 936                 lttng_live_msg_iter);
 937         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 938                 goto end;
 939         }
 940         live_status = lttng_live_iterator_next_handle_one_no_data_stream(
 941                 lttng_live_msg_iter, stream_iter);
 942
 943         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 944                 if (live_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
 945                         /*
 946                          * We overwrite `live_status` since `curr_msg` is
 947                          * likely set to a valid message in this function.
 948                          */
 949                         live_status = lttng_live_iterator_close_stream(
 950                                 lttng_live_msg_iter, stream_iter, curr_msg);
 951                 }
 952                 goto end;
 953         }
 954         live_status = lttng_live_iterator_next_handle_one_quiescent_stream(
 955                 lttng_live_msg_iter, stream_iter, curr_msg);
 956         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 957                 BT_ASSERT(!*curr_msg);
 958                 goto end;
 959         }
 960         if (*curr_msg) {
 961                 goto end;
 962         }
 963         live_status = lttng_live_iterator_next_handle_one_active_data_stream(
 964                 lttng_live_msg_iter, stream_iter, curr_msg);
 965         if (live_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
 966                 BT_ASSERT(!*curr_msg);
 967         }
 968
 969 end:
 970         if (live_status == LTTNG_LIVE_ITERATOR_STATUS_CONTINUE) {
 971                 goto retry;
 972         }
 973
 974         return live_status;
 975 }
 976
 977 static
 978 enum lttng_live_iterator_status next_stream_iterator_for_trace(
 979                 struct lttng_live_msg_iter *lttng_live_msg_iter,
 980                 struct lttng_live_trace *live_trace,
 981                 struct lttng_live_stream_iterator **youngest_trace_stream_iter)
 982 {
 983         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
 984         bt_logging_level log_level = lttng_live_msg_iter->log_level;
 985         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
 986         enum lttng_live_iterator_status stream_iter_status;;
 987         int64_t youngest_candidate_msg_ts = INT64_MAX;
 988         uint64_t stream_iter_idx;
 989
 990         BT_ASSERT_DBG(live_trace);
 991         BT_ASSERT_DBG(live_trace->stream_iterators);
 992         /*
 993          * Update the current message of every stream iterators of this trace.
 994          * The current msg of every stream must have a timestamp equal or
 995          * larger than the last message returned by this iterator. We must
 996          * ensure monotonicity.
 997          */
 998         stream_iter_idx = 0;
 999         while (stream_iter_idx < live_trace->stream_iterators->len) {
1000                 bool stream_iter_is_ended = false;
1001                 struct lttng_live_stream_iterator *stream_iter =
1002                         g_ptr_array_index(live_trace->stream_iterators,
1003                                 stream_iter_idx);
1004
1005                 /*
1006                  * Find if there is are now current message for this stream
1007                  * iterator get it.
1008                  */
1009                 while (!stream_iter->current_msg) {
1010                         bt_message *msg = NULL;
1011                         int64_t curr_msg_ts_ns = INT64_MAX;
1012                         stream_iter_status = lttng_live_iterator_next_msg_on_stream(
1013                                 lttng_live_msg_iter, stream_iter, &msg);
1014
1015                         BT_COMP_LOGD("live stream iterator returned status :%s",
1016                                 print_live_iterator_status(stream_iter_status));
1017                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1018                                 stream_iter_is_ended = true;
1019                                 break;
1020                         }
1021
1022                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1023                                 goto end;
1024                         }
1025
1026                         BT_ASSERT_DBG(msg);
1027
1028                         /*
1029                          * Get the timestamp in nanoseconds from origin of this
1030                          * messsage.
1031                          */
1032                         live_get_msg_ts_ns(stream_iter, lttng_live_msg_iter,
1033                                 msg, lttng_live_msg_iter->last_msg_ts_ns,
1034                                 &curr_msg_ts_ns);
1035
1036                         /*
1037                          * Check if the message of the current live stream
1038                          * iterator occured at the exact same time or after the
1039                          * last message returned by this component's message
1040                          * iterator. If not, we return an error.
1041                          */
1042                         if (curr_msg_ts_ns >= lttng_live_msg_iter->last_msg_ts_ns) {
1043                                 stream_iter->current_msg = msg;
1044                                 stream_iter->current_msg_ts_ns = curr_msg_ts_ns;
1045                         } else {
1046                                 /*
1047                                  * We received a message in the past. To ensure
1048                                  * monotonicity, we can't send it forward.
1049                                  */
1050                                 BT_COMP_LOGE_APPEND_CAUSE(self_comp,
1051                                         "Message's timestamp is less than "
1052                                         "lttng-live's message iterator's last "
1053                                         "returned timestamp: "
1054                                         "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
1055                                         "last-msg-ts=%" PRId64,
1056                                         lttng_live_msg_iter, curr_msg_ts_ns,
1057                                         lttng_live_msg_iter->last_msg_ts_ns);
1058                                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1059                                 goto end;
1060                         }
1061                 }
1062
1063                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1064
1065                 if (!stream_iter_is_ended) {
1066                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1067                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1068                                 /*
1069                                  * Update the current best candidate message
1070                                  * for the stream iterator of this live trace
1071                                  * to be forwarded downstream.
1072                                  */
1073                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1074                                 youngest_candidate_stream_iter = stream_iter;
1075                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1076                                 /*
1077                                  * Order the messages in an arbitrary but
1078                                  * deterministic way.
1079                                  */
1080                                 BT_ASSERT_DBG(stream_iter != youngest_candidate_stream_iter);
1081                                 int ret = common_muxing_compare_messages(
1082                                         stream_iter->current_msg,
1083                                         youngest_candidate_stream_iter->current_msg);
1084                                 if (ret < 0) {
1085                                         /*
1086                                          * The `youngest_candidate_stream_iter->current_msg`
1087                                          * should go first. Update the next
1088                                          * iterator and the current timestamp.
1089                                          */
1090                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1091                                         youngest_candidate_stream_iter = stream_iter;
1092                                 } else if (ret == 0) {
1093                                         /*
1094                                          * Unable to pick which one should go
1095                                          * first.
1096                                          */
1097                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1098                                                 "stream-iter-addr=%p"
1099                                                 "stream-iter-addr=%p",
1100                                                 stream_iter,
1101                                                 youngest_candidate_stream_iter);
1102                                 }
1103                         }
1104
1105                         stream_iter_idx++;
1106                 } else {
1107                         /*
1108                          * The live stream iterator has ended. That
1109                          * iterator is removed from the array, but
1110                          * there is no need to increment
1111                          * stream_iter_idx as
1112                          * g_ptr_array_remove_index_fast replaces the
1113                          * removed element with the array's last
1114                          * element.
1115                          */
1116                         g_ptr_array_remove_index_fast(
1117                                 live_trace->stream_iterators,
1118                                 stream_iter_idx);
1119                 }
1120         }
1121
1122         if (youngest_candidate_stream_iter) {
1123                 *youngest_trace_stream_iter = youngest_candidate_stream_iter;
1124                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1125         } else {
1126                 /*
1127                  * The only case where we don't have a candidate for this trace
1128                  * is if we reached the end of all the iterators.
1129                  */
1130                 BT_ASSERT(live_trace->stream_iterators->len == 0);
1131                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1132         }
1133
1134 end:
1135         return stream_iter_status;
1136 }
1137
1138 static
1139 enum lttng_live_iterator_status next_stream_iterator_for_session(
1140                 struct lttng_live_msg_iter *lttng_live_msg_iter,
1141                 struct lttng_live_session *session,
1142                 struct lttng_live_stream_iterator **youngest_session_stream_iter)
1143 {
1144         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1145         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1146         enum lttng_live_iterator_status stream_iter_status;
1147         uint64_t trace_idx = 0;
1148         int64_t youngest_candidate_msg_ts = INT64_MAX;
1149         struct lttng_live_stream_iterator *youngest_candidate_stream_iter = NULL;
1150
1151         /*
1152          * Make sure we are attached to the session and look for new streams
1153          * and metadata.
1154          */
1155         stream_iter_status = lttng_live_get_session(lttng_live_msg_iter, session);
1156         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
1157                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_CONTINUE &&
1158                         stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_END) {
1159                 goto end;
1160         }
1161
1162         BT_ASSERT_DBG(session->traces);
1163
1164         while (trace_idx < session->traces->len) {
1165                 bool trace_is_ended = false;
1166                 struct lttng_live_stream_iterator *stream_iter;
1167                 struct lttng_live_trace *trace =
1168                         g_ptr_array_index(session->traces, trace_idx);
1169
1170                 stream_iter_status = next_stream_iterator_for_trace(
1171                         lttng_live_msg_iter, trace, &stream_iter);
1172                 if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1173                         /*
1174                          * All the live stream iterators for this trace are
1175                          * ENDed. Remove the trace from this session.
1176                          */
1177                         trace_is_ended = true;
1178                 } else if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1179                         goto end;
1180                 }
1181
1182                 if (!trace_is_ended) {
1183                         BT_ASSERT_DBG(stream_iter);
1184
1185                         if (G_UNLIKELY(youngest_candidate_stream_iter == NULL) ||
1186                                         stream_iter->current_msg_ts_ns < youngest_candidate_msg_ts) {
1187                                 youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1188                                 youngest_candidate_stream_iter = stream_iter;
1189                         } else if (stream_iter->current_msg_ts_ns == youngest_candidate_msg_ts) {
1190                                 /*
1191                                  * Order the messages in an arbitrary but
1192                                  * deterministic way.
1193                                  */
1194                                 int ret = common_muxing_compare_messages(
1195                                         stream_iter->current_msg,
1196                                         youngest_candidate_stream_iter->current_msg);
1197                                 if (ret < 0) {
1198                                         /*
1199                                          * The `youngest_candidate_stream_iter->current_msg`
1200                                          * should go first. Update the next iterator
1201                                          * and the current timestamp.
1202                                          */
1203                                         youngest_candidate_msg_ts = stream_iter->current_msg_ts_ns;
1204                                         youngest_candidate_stream_iter = stream_iter;
1205                                 } else if (ret == 0) {
1206                                         /* Unable to pick which one should go first. */
1207                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1208                                                 "stream-iter-addr=%p" "stream-iter-addr=%p",
1209                                                 stream_iter, youngest_candidate_stream_iter);
1210                                 }
1211                         }
1212                         trace_idx++;
1213                 } else {
1214                         /*
1215                          * trace_idx is not incremented since
1216                          * g_ptr_array_remove_index_fast replaces the
1217                          * element at trace_idx with the array's last element.
1218                          */
1219                         g_ptr_array_remove_index_fast(session->traces,
1220                                 trace_idx);
1221                 }
1222         }
1223         if (youngest_candidate_stream_iter) {
1224                 *youngest_session_stream_iter = youngest_candidate_stream_iter;
1225                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1226         } else {
1227                 /*
1228                  * The only cases where we don't have a candidate for this
1229                  * trace is:
1230                  *  1. if we reached the end of all the iterators of all the
1231                  *  traces of this session,
1232                  *  2. if we never had live stream iterator in the first place.
1233                  *
1234                  * In either cases, we return END.
1235                  */
1236                 BT_ASSERT(session->traces->len == 0);
1237                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_END;
1238         }
1239 end:
1240         return stream_iter_status;
1241 }
1242
1243 static inline
1244 void put_messages(bt_message_array_const msgs, uint64_t count)
1245 {
1246         uint64_t i;
1247
1248         for (i = 0; i < count; i++) {
1249                 BT_MESSAGE_PUT_REF_AND_RESET(msgs[i]);
1250         }
1251 }
1252
1253 BT_HIDDEN
1254 bt_component_class_message_iterator_next_method_status lttng_live_msg_iter_next(
1255                 bt_self_message_iterator *self_msg_it,
1256                 bt_message_array_const msgs, uint64_t capacity,
1257                 uint64_t *count)
1258 {
1259         bt_component_class_message_iterator_next_method_status status;
1260         struct lttng_live_msg_iter *lttng_live_msg_iter =
1261                 bt_self_message_iterator_get_data(self_msg_it);
1262         struct lttng_live_component *lttng_live =
1263                 lttng_live_msg_iter->lttng_live_comp;
1264         bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
1265         bt_logging_level log_level = lttng_live_msg_iter->log_level;
1266         enum lttng_live_iterator_status stream_iter_status;
1267         uint64_t session_idx;
1268
1269         *count = 0;
1270
1271         BT_ASSERT_DBG(lttng_live_msg_iter);
1272
1273         /*
1274          * Clear all the invalid message reference that might be left over in
1275          * the output array.
1276          */
1277         memset(msgs, 0, capacity * sizeof(*msgs));
1278
1279         /*
1280          * If no session are exposed on the relay found at the url provided by
1281          * the user, session count will be 0. In this case, we return status
1282          * end to return gracefully.
1283          */
1284         if (lttng_live_msg_iter->sessions->len == 0) {
1285                 if (lttng_live->params.sess_not_found_act !=
1286                                 SESSION_NOT_FOUND_ACTION_CONTINUE) {
1287                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1288                         goto no_session;
1289                 } else {
1290                         /*
1291                          * The are no more active session for this session
1292                          * name. Retry to create a viewer session for the
1293                          * requested session name.
1294                          */
1295                         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1296                                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1297                                 goto no_session;
1298                         }
1299                 }
1300         }
1301
1302         if (lttng_live_msg_iter->active_stream_iter == 0) {
1303                 lttng_live_force_new_streams_and_metadata(lttng_live_msg_iter);
1304         }
1305
1306         /*
1307          * Here the muxing of message is done.
1308          *
1309          * We need to iterate over all the streams of all the traces of all the
1310          * viewer sessions in order to get the message with the smallest
1311          * timestamp. In this case, a session is a viewer session and there is
1312          * one viewer session per consumer daemon. (UST 32bit, UST 64bit and/or
1313          * kernel). Each viewer session can have multiple traces, for example,
1314          * 64bit UST viewer sessions could have multiple per-pid traces.
1315          *
1316          * We iterate over the streams of each traces to update and see what is
1317          * their next message's timestamp. From those timestamps, we select the
1318          * message with the smallest timestamp as the best candidate message
1319          * for that trace and do the same thing across all the sessions.
1320          *
1321          * We then compare the timestamp of best candidate message of all the
1322          * sessions to pick the message with the smallest timestamp and we
1323          * return it.
1324          */
1325         while (*count < capacity) {
1326                 struct lttng_live_stream_iterator *youngest_stream_iter = NULL,
1327                           *candidate_stream_iter = NULL;
1328                 int64_t youngest_msg_ts_ns = INT64_MAX;
1329
1330                 BT_ASSERT_DBG(lttng_live_msg_iter->sessions);
1331                 session_idx = 0;
1332                 while (session_idx < lttng_live_msg_iter->sessions->len) {
1333                         struct lttng_live_session *session =
1334                                 g_ptr_array_index(lttng_live_msg_iter->sessions,
1335                                         session_idx);
1336
1337                         /* Find the best candidate message to send downstream. */
1338                         stream_iter_status = next_stream_iterator_for_session(
1339                                 lttng_live_msg_iter, session,
1340                                 &candidate_stream_iter);
1341
1342                         /* If we receive an END status, it means that either:
1343                          * - Those traces never had active streams (UST with no
1344                          *   data produced yet),
1345                          * - All live stream iterators have ENDed.*/
1346                         if (stream_iter_status == LTTNG_LIVE_ITERATOR_STATUS_END) {
1347                                 if (session->closed && session->traces->len == 0) {
1348                                         /*
1349                                          * Remove the session from the list.
1350                                          * session_idx is not modified since
1351                                          * g_ptr_array_remove_index_fast
1352                                          * replaces the the removed element with
1353                                          * the array's last element.
1354                                          */
1355                                         g_ptr_array_remove_index_fast(
1356                                                 lttng_live_msg_iter->sessions,
1357                                                 session_idx);
1358                                 } else {
1359                                         session_idx++;
1360                                 }
1361                                 continue;
1362                         }
1363
1364                         if (stream_iter_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
1365                                 goto end;
1366                         }
1367
1368                         if (G_UNLIKELY(youngest_stream_iter == NULL) ||
1369                                         candidate_stream_iter->current_msg_ts_ns < youngest_msg_ts_ns) {
1370                                 youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1371                                 youngest_stream_iter = candidate_stream_iter;
1372                         } else if (candidate_stream_iter->current_msg_ts_ns == youngest_msg_ts_ns) {
1373                                 /*
1374                                  * The currently selected message to be sent
1375                                  * downstream next has the exact same timestamp
1376                                  * that of the current candidate message. We
1377                                  * must break the tie in a predictable manner.
1378                                  */
1379                                 BT_COMP_LOGD_STR("Two of the next message candidates have the same timestamps, pick one deterministically.");
1380                                 /*
1381                                  * Order the messages in an arbitrary but
1382                                  * deterministic way.
1383                                  */
1384                                 int ret = common_muxing_compare_messages(
1385                                         candidate_stream_iter->current_msg,
1386                                         youngest_stream_iter->current_msg);
1387                                 if (ret < 0) {
1388                                         /*
1389                                          * The `candidate_stream_iter->current_msg`
1390                                          * should go first. Update the next
1391                                          * iterator and the current timestamp.
1392                                          */
1393                                         youngest_msg_ts_ns = candidate_stream_iter->current_msg_ts_ns;
1394                                         youngest_stream_iter = candidate_stream_iter;
1395                                 } else if (ret == 0) {
1396                                         /* Unable to pick which one should go first. */
1397                                         BT_COMP_LOGW("Cannot deterministically pick next live stream message iterator because they have identical next messages: "
1398                                                 "next-stream-iter-addr=%p" "candidate-stream-iter-addr=%p",
1399                                                 youngest_stream_iter, candidate_stream_iter);
1400                                 }
1401                         }
1402
1403                         session_idx++;
1404                 }
1405
1406                 if (!youngest_stream_iter) {
1407                         stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1408                         goto end;
1409                 }
1410
1411                 BT_ASSERT_DBG(youngest_stream_iter->current_msg);
1412                 /* Ensure monotonicity. */
1413                 BT_ASSERT_DBG(lttng_live_msg_iter->last_msg_ts_ns <=
1414                         youngest_stream_iter->current_msg_ts_ns);
1415
1416                 /*
1417                  * Insert the next message to the message batch. This will set
1418                  * stream iterator current messsage to NULL so that next time
1419                  * we fetch the next message of that stream iterator
1420                  */
1421                 BT_MESSAGE_MOVE_REF(msgs[*count], youngest_stream_iter->current_msg);
1422                 (*count)++;
1423
1424                 /* Update the last timestamp in nanoseconds sent downstream. */
1425                 lttng_live_msg_iter->last_msg_ts_ns = youngest_msg_ts_ns;
1426                 youngest_stream_iter->current_msg_ts_ns = INT64_MAX;
1427
1428                 stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
1429         }
1430 end:
1431         switch (stream_iter_status) {
1432         case LTTNG_LIVE_ITERATOR_STATUS_OK:
1433         case LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
1434                 if (*count > 0) {
1435                         /*
1436                          * We received a again status but we have some messages
1437                          * to send downstream. We send them and return OK for
1438                          * now. On the next call we return again if there are
1439                          * still no new message to send.
1440                          */
1441                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK;
1442                 } else {
1443                         status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_AGAIN;
1444                 }
1445                 break;
1446         case LTTNG_LIVE_ITERATOR_STATUS_END:
1447                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_END;
1448                 break;
1449         case LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
1450                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_MEMORY_ERROR;
1451                 break;
1452         case LTTNG_LIVE_ITERATOR_STATUS_ERROR:
1453         case LTTNG_LIVE_ITERATOR_STATUS_INVAL:
1454         case LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
1455                 status = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_ERROR;
1456                 /* Put all existing messages on error. */
1457                 put_messages(msgs, *count);
1458                 break;
1459         default:
1460                 abort();
1461         }
1462
1463 no_session:
1464         return status;
1465 }
1466
1467 BT_HIDDEN
1468 bt_component_class_message_iterator_initialize_method_status lttng_live_msg_iter_init(
1469                 bt_self_message_iterator *self_msg_it,
1470                 bt_self_message_iterator_configuration *config,
1471                 bt_self_component_source *self_comp_src,
1472                 bt_self_component_port_output *self_port)
1473 {
1474         bt_component_class_message_iterator_initialize_method_status ret =
1475                 BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_OK;
1476         bt_self_component *self_comp =
1477                 bt_self_component_source_as_self_component(self_comp_src);
1478         struct lttng_live_component *lttng_live;
1479         struct lttng_live_msg_iter *lttng_live_msg_iter;
1480         bt_logging_level log_level;
1481
1482         BT_ASSERT(self_msg_it);
1483
1484         lttng_live = bt_self_component_get_data(self_comp);
1485         log_level = lttng_live->log_level;
1486         self_comp = lttng_live->self_comp;
1487
1488         /* There can be only one downstream iterator at the same time. */
1489         BT_ASSERT(!lttng_live->has_msg_iter);
1490         lttng_live->has_msg_iter = true;
1491
1492         lttng_live_msg_iter = g_new0(struct lttng_live_msg_iter, 1);
1493         if (!lttng_live_msg_iter) {
1494                 ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1495                 goto end;
1496         }
1497
1498         lttng_live_msg_iter->log_level = lttng_live->log_level;
1499         lttng_live_msg_iter->self_comp = lttng_live->self_comp;
1500         lttng_live_msg_iter->lttng_live_comp = lttng_live;
1501         lttng_live_msg_iter->self_msg_iter = self_msg_it;
1502
1503         lttng_live_msg_iter->active_stream_iter = 0;
1504         lttng_live_msg_iter->last_msg_ts_ns = INT64_MIN;
1505         lttng_live_msg_iter->sessions = g_ptr_array_new_with_free_func(
1506                 (GDestroyNotify) lttng_live_destroy_session);
1507         BT_ASSERT(lttng_live_msg_iter->sessions);
1508
1509         lttng_live_msg_iter->viewer_connection =
1510                 live_viewer_connection_create(lttng_live->params.url->str, false,
1511                         lttng_live_msg_iter, self_comp, NULL, log_level);
1512         if (!lttng_live_msg_iter->viewer_connection) {
1513                 goto error;
1514         }
1515
1516         if (lttng_live_create_viewer_session(lttng_live_msg_iter)) {
1517                 goto error;
1518         }
1519         if (lttng_live_msg_iter->sessions->len == 0) {
1520                 switch (lttng_live->params.sess_not_found_act) {
1521                 case SESSION_NOT_FOUND_ACTION_CONTINUE:
1522                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1523                                 "session. Keep trying to connect because of "
1524                                 "%s=\"%s\" component parameter: url=\"%s\"",
1525                                 SESS_NOT_FOUND_ACTION_PARAM,
1526                                 SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1527                                 lttng_live->params.url->str);
1528                         break;
1529                 case SESSION_NOT_FOUND_ACTION_FAIL:
1530                         BT_COMP_LOGE_APPEND_CAUSE(self_comp, "Unable to connect to the requested live viewer "
1531                                 "session. Fail the message iterator"
1532                                 "initialization because of %s=\"%s\" "
1533                                 "component parameter: url =\"%s\"",
1534                                 SESS_NOT_FOUND_ACTION_PARAM,
1535                                 SESS_NOT_FOUND_ACTION_FAIL_STR,
1536                                 lttng_live->params.url->str);
1537                         goto error;
1538                 case SESSION_NOT_FOUND_ACTION_END:
1539                         BT_COMP_LOGI("Unable to connect to the requested live viewer "
1540                                 "session. End gracefully at the first _next() "
1541                                 "call because of %s=\"%s\" component parameter: "
1542                                 "url=\"%s\"", SESS_NOT_FOUND_ACTION_PARAM,
1543                                 SESS_NOT_FOUND_ACTION_END_STR,
1544                                 lttng_live->params.url->str);
1545                         break;
1546                 default:
1547                         abort();
1548                 }
1549         }
1550
1551         bt_self_message_iterator_set_data(self_msg_it, lttng_live_msg_iter);
1552
1553         goto end;
1554 error:
1555         ret = BT_COMPONENT_CLASS_MESSAGE_ITERATOR_INITIALIZE_METHOD_STATUS_ERROR;
1556         lttng_live_msg_iter_destroy(lttng_live_msg_iter);
1557 end:
1558         return ret;
1559 }
1560
1561 static struct bt_param_validation_map_value_entry_descr list_sessions_params[] = {
1562         { URL_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { .type = BT_VALUE_TYPE_STRING } },
1563         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1564 };
1565
1566 static
1567 bt_component_class_query_method_status lttng_live_query_list_sessions(
1568                 const bt_value *params, const bt_value **result,
1569                 bt_self_component_class *self_comp_class,
1570                 bt_logging_level log_level)
1571 {
1572         bt_component_class_query_method_status status;
1573         const bt_value *url_value = NULL;
1574         const char *url;
1575         struct live_viewer_connection *viewer_connection = NULL;
1576         enum bt_param_validation_status validation_status;
1577         gchar *validate_error = NULL;
1578
1579         validation_status = bt_param_validation_validate(params,
1580                 list_sessions_params, &validate_error);
1581         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1582                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1583                 goto error;
1584         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1585                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1586                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class, "%s",
1587                         validate_error);
1588                 goto error;
1589         }
1590
1591         url_value = bt_value_map_borrow_entry_value_const(params, URL_PARAM);
1592         url = bt_value_string_get(url_value);
1593
1594         viewer_connection = live_viewer_connection_create(url, true, NULL,
1595                 NULL, self_comp_class, log_level);
1596         if (!viewer_connection) {
1597                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1598                         "Failed to create viewer connection");
1599                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1600                 goto error;
1601         }
1602
1603         status = live_viewer_connection_list_sessions(viewer_connection,
1604                 result);
1605         if (status != BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK) {
1606                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1607                         "Failed to list viewer sessions");
1608                 goto error;
1609         }
1610
1611         goto end;
1612
1613 error:
1614         BT_VALUE_PUT_REF_AND_RESET(*result);
1615
1616         if (status >= 0) {
1617                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1618         }
1619
1620 end:
1621         if (viewer_connection) {
1622                 live_viewer_connection_destroy(viewer_connection);
1623         }
1624
1625         g_free(validate_error);
1626
1627         return status;
1628 }
1629
1630 static
1631 bt_component_class_query_method_status lttng_live_query_support_info(
1632                 const bt_value *params, const bt_value **result,
1633                 bt_self_component_class *self_comp_class,
1634                 bt_logging_level log_level)
1635 {
1636         bt_component_class_query_method_status status =
1637                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1638         const bt_value *input_type_value;
1639         const bt_value *input_value;
1640         double weight = 0;
1641         struct bt_common_lttng_live_url_parts parts = { 0 };
1642
1643         /* Used by the logging macros */
1644         __attribute__((unused)) bt_self_component *self_comp = NULL;
1645
1646         *result = NULL;
1647         input_type_value = bt_value_map_borrow_entry_value_const(params,
1648                 "type");
1649         if (!input_type_value) {
1650                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1651                         "Missing expected `type` parameter.");
1652                 goto error;
1653         }
1654
1655         if (!bt_value_is_string(input_type_value)) {
1656                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1657                         "`type` parameter is not a string value.");
1658                 goto error;
1659         }
1660
1661         if (strcmp(bt_value_string_get(input_type_value), "string") != 0) {
1662                 /* We don't handle file system paths */
1663                 goto create_result;
1664         }
1665
1666         input_value = bt_value_map_borrow_entry_value_const(params, "input");
1667         if (!input_value) {
1668                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1669                         "Missing expected `input` parameter.");
1670                 goto error;
1671         }
1672
1673         if (!bt_value_is_string(input_value)) {
1674                 BT_COMP_CLASS_LOGE_APPEND_CAUSE(self_comp_class,
1675                         "`input` parameter is not a string value.");
1676                 goto error;
1677         }
1678
1679         parts = bt_common_parse_lttng_live_url(bt_value_string_get(input_value),
1680                 NULL, 0);
1681         if (parts.session_name) {
1682                 /*
1683                  * Looks pretty much like an LTTng live URL: we got the
1684                  * session name part, which forms a complete URL.
1685                  */
1686                 weight = .75;
1687         }
1688
1689 create_result:
1690         *result = bt_value_real_create_init(weight);
1691         if (!*result) {
1692                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
1693                 goto error;
1694         }
1695
1696         goto end;
1697
1698 error:
1699         if (status >= 0) {
1700                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
1701         }
1702
1703         BT_ASSERT(!*result);
1704
1705 end:
1706         bt_common_destroy_lttng_live_url_parts(&parts);
1707         return status;
1708 }
1709
1710 BT_HIDDEN
1711 bt_component_class_query_method_status lttng_live_query(
1712                 bt_self_component_class_source *comp_class,
1713                 bt_private_query_executor *priv_query_exec,
1714                 const char *object, const bt_value *params,
1715                 __attribute__((unused)) void *method_data,
1716                 const bt_value **result)
1717 {
1718         bt_component_class_query_method_status status =
1719                 BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
1720         bt_self_component *self_comp = NULL;
1721         bt_self_component_class *self_comp_class =
1722                 bt_self_component_class_source_as_self_component_class(comp_class);
1723         bt_logging_level log_level = bt_query_executor_get_logging_level(
1724                 bt_private_query_executor_as_query_executor_const(
1725                         priv_query_exec));
1726
1727         if (strcmp(object, "sessions") == 0) {
1728                 status = lttng_live_query_list_sessions(params, result,
1729                         self_comp_class, log_level);
1730         } else if (strcmp(object, "babeltrace.support-info") == 0) {
1731                 status = lttng_live_query_support_info(params, result,
1732                         self_comp_class, log_level);
1733         } else {
1734                 BT_COMP_LOGI("Unknown query object `%s`", object);
1735                 status = BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
1736                 goto end;
1737         }
1738
1739 end:
1740         return status;
1741 }
1742
1743 static
1744 void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
1745 {
1746         if (!lttng_live) {
1747                 return;
1748         }
1749         if (lttng_live->params.url) {
1750                 g_string_free(lttng_live->params.url, TRUE);
1751         }
1752         g_free(lttng_live);
1753 }
1754
1755 BT_HIDDEN
1756 void lttng_live_component_finalize(bt_self_component_source *component)
1757 {
1758         void *data = bt_self_component_get_data(
1759                 bt_self_component_source_as_self_component(component));
1760
1761         if (!data) {
1762                 return;
1763         }
1764         lttng_live_component_destroy_data(data);
1765 }
1766
1767 static
1768 enum session_not_found_action parse_session_not_found_action_param(
1769         const bt_value *no_session_param)
1770 {
1771         enum session_not_found_action action;
1772         const char *no_session_act_str = bt_value_string_get(no_session_param);
1773
1774         if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_CONTINUE_STR) == 0) {
1775                 action = SESSION_NOT_FOUND_ACTION_CONTINUE;
1776         } else if (strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_FAIL_STR) == 0) {
1777                 action = SESSION_NOT_FOUND_ACTION_FAIL;
1778         } else {
1779                 BT_ASSERT(strcmp(no_session_act_str, SESS_NOT_FOUND_ACTION_END_STR) == 0);
1780                 action = SESSION_NOT_FOUND_ACTION_END;
1781         }
1782
1783         return action;
1784 }
1785
1786 static struct bt_param_validation_value_descr inputs_elem_descr = {
1787         .type = BT_VALUE_TYPE_STRING,
1788 };
1789
1790 static const char *sess_not_found_action_choices[] = {
1791         SESS_NOT_FOUND_ACTION_CONTINUE_STR,
1792         SESS_NOT_FOUND_ACTION_FAIL_STR,
1793         SESS_NOT_FOUND_ACTION_END_STR,
1794 };
1795
1796 static struct bt_param_validation_map_value_entry_descr params_descr[] = {
1797         { INPUTS_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY, { BT_VALUE_TYPE_ARRAY, .array = {
1798                 .min_length = 1,
1799                 .max_length = 1,
1800                 .element_type = &inputs_elem_descr,
1801         } } },
1802         { SESS_NOT_FOUND_ACTION_PARAM, BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL, { BT_VALUE_TYPE_STRING, .string = {
1803                 .choices = sess_not_found_action_choices,
1804         } } },
1805         BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END
1806 };
1807
1808 static
1809 bt_component_class_initialize_method_status lttng_live_component_create(
1810                 const bt_value *params,
1811                 bt_logging_level log_level,
1812                 bt_self_component *self_comp,
1813                 struct lttng_live_component **component)
1814 {
1815         struct lttng_live_component *lttng_live = NULL;
1816         const bt_value *inputs_value;
1817         const bt_value *url_value;
1818         const bt_value *value;
1819         const char *url;
1820         enum bt_param_validation_status validation_status;
1821         gchar *validation_error = NULL;
1822         bt_component_class_initialize_method_status status;
1823
1824         validation_status = bt_param_validation_validate(params, params_descr,
1825                 &validation_error);
1826         if (validation_status == BT_PARAM_VALIDATION_STATUS_MEMORY_ERROR) {
1827                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1828                 goto error;
1829         } else if (validation_status == BT_PARAM_VALIDATION_STATUS_VALIDATION_ERROR) {
1830                 BT_COMP_LOGE_APPEND_CAUSE(self_comp, "%s", validation_error);
1831                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
1832                 goto error;
1833         }
1834
1835         lttng_live = g_new0(struct lttng_live_component, 1);
1836         if (!lttng_live) {
1837                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1838                 goto end;
1839         }
1840         lttng_live->log_level = log_level;
1841         lttng_live->self_comp = self_comp;
1842         lttng_live->max_query_size = MAX_QUERY_SIZE;
1843         lttng_live->has_msg_iter = false;
1844
1845         inputs_value =
1846                 bt_value_map_borrow_entry_value_const(params, INPUTS_PARAM);
1847         url_value =
1848                 bt_value_array_borrow_element_by_index_const(inputs_value, 0);
1849         url = bt_value_string_get(url_value);
1850
1851         lttng_live->params.url = g_string_new(url);
1852         if (!lttng_live->params.url) {
1853                 status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
1854                 goto error;
1855         }
1856
1857         value = bt_value_map_borrow_entry_value_const(params,
1858                 SESS_NOT_FOUND_ACTION_PARAM);
1859         if (value) {
1860                 lttng_live->params.sess_not_found_act =
1861                         parse_session_not_found_action_param(value);
1862         } else {
1863                 BT_COMP_LOGI("Optional `%s` parameter is missing: "
1864                         "defaulting to `%s`.",
1865                         SESS_NOT_FOUND_ACTION_PARAM,
1866                         SESS_NOT_FOUND_ACTION_CONTINUE_STR);
1867                 lttng_live->params.sess_not_found_act =
1868                         SESSION_NOT_FOUND_ACTION_CONTINUE;
1869         }
1870
1871         status = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;
1872         goto end;
1873
1874 error:
1875         lttng_live_component_destroy_data(lttng_live);
1876         lttng_live = NULL;
1877 end:
1878         g_free(validation_error);
1879
1880         *component = lttng_live;
1881         return status;
1882 }
1883
1884 BT_HIDDEN
1885 bt_component_class_initialize_method_status lttng_live_component_init(
1886                 bt_self_component_source *self_comp_src,
1887                 bt_self_component_source_configuration *config,
1888                 const bt_value *params,
1889                 __attribute__((unused)) void *init_method_data)
1890 {
1891         struct lttng_live_component *lttng_live;
1892         bt_component_class_initialize_method_status ret;
1893         bt_self_component *self_comp =
1894                 bt_self_component_source_as_self_component(self_comp_src);
1895         bt_logging_level log_level = bt_component_get_logging_level(
1896                 bt_self_component_as_component(self_comp));
1897         bt_self_component_add_port_status add_port_status;
1898
1899         ret = lttng_live_component_create(params, log_level, self_comp, &lttng_live);
1900         if (ret != BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK) {
1901                 goto error;
1902         }
1903
1904         add_port_status = bt_self_component_source_add_output_port(
1905                 self_comp_src, "out", NULL, NULL);
1906         if (add_port_status != BT_SELF_COMPONENT_ADD_PORT_STATUS_OK) {
1907                 ret = (int) add_port_status;
1908                 goto end;
1909         }
1910
1911         bt_self_component_set_data(self_comp, lttng_live);
1912         goto end;
1913
1914 error:
1915         lttng_live_component_destroy_data(lttng_live);
1916         lttng_live = NULL;
1917 end:
1918         return ret;
1919 }