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