src/plugins/ctf/lttng-live/viewer-connection.cpp

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2019 Francis Deslauriers <francis.deslauriers@efficios.com>
   5  * Copyright 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  */
   7
   8 #include <glib.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11
  12 #include <babeltrace2/babeltrace.h>
  13
  14 #include "common/common.h"
  15 #include "compat/endian.h" /* IWYU pragma: keep  */
  16 #include "cpp-common/bt2s/make-unique.hpp"
  17
  18 #include "data-stream.hpp"
  19 #include "lttng-live.hpp"
  20 #include "lttng-viewer-abi.hpp"
  21 #include "metadata.hpp"
  22 #include "viewer-connection.hpp"
  23
  24 #define viewer_handle_send_recv_status(_status, _action, _msg_str)                                 \
  25     do {                                                                                           \
  26         switch (_status) {                                                                         \
  27         case LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED:                                                 \
  28             break;                                                                                 \
  29         case LTTNG_LIVE_VIEWER_STATUS_ERROR:                                                       \
  30             BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,                                \
  31                                          "Error " _action " " _msg_str);                           \
  32             break;                                                                                 \
  33         default:                                                                                   \
  34             bt_common_abort();                                                                     \
  35         }                                                                                          \
  36     } while (0)
  37
  38 #define viewer_handle_send_status(_status, _msg_str)                                               \
  39     viewer_handle_send_recv_status(_status, "sending", _msg_str)
  40
  41 #define viewer_handle_recv_status(_status, _msg_str)                                               \
  42     viewer_handle_send_recv_status(_status, "receiving", _msg_str)
  43
  44 #define LTTNG_LIVE_CPPLOGE_APPEND_CAUSE_ERRNO(_msg, _fmt, ...)                                     \
  45     do {                                                                                           \
  46         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, _msg ": {}" _fmt,                  \
  47                                      bt_socket_errormsg(), ##__VA_ARGS__);                         \
  48     } while (0)
  49
  50 static inline enum lttng_live_iterator_status
  51 viewer_status_to_live_iterator_status(enum lttng_live_viewer_status viewer_status)
  52 {
  53     switch (viewer_status) {
  54     case LTTNG_LIVE_VIEWER_STATUS_OK:
  55         return LTTNG_LIVE_ITERATOR_STATUS_OK;
  56     case LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED:
  57         return LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
  58     case LTTNG_LIVE_VIEWER_STATUS_ERROR:
  59         return LTTNG_LIVE_ITERATOR_STATUS_ERROR;
  60     }
  61
  62     bt_common_abort();
  63 }
  64
  65 static inline enum ctf_msg_iter_medium_status
  66 viewer_status_to_ctf_msg_iter_medium_status(enum lttng_live_viewer_status viewer_status)
  67 {
  68     switch (viewer_status) {
  69     case LTTNG_LIVE_VIEWER_STATUS_OK:
  70         return CTF_MSG_ITER_MEDIUM_STATUS_OK;
  71     case LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED:
  72         return CTF_MSG_ITER_MEDIUM_STATUS_AGAIN;
  73     case LTTNG_LIVE_VIEWER_STATUS_ERROR:
  74         return CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
  75     }
  76
  77     bt_common_abort();
  78 }
  79
  80 static inline void viewer_connection_close_socket(struct live_viewer_connection *viewer_connection)
  81 {
  82     if (viewer_connection->control_sock == BT_INVALID_SOCKET) {
  83         return;
  84     }
  85
  86     int ret = bt_socket_close(viewer_connection->control_sock);
  87     if (ret == -1) {
  88         BT_CPPLOGW_ERRNO_SPEC(viewer_connection->logger,
  89                               "Error closing viewer connection socket: ", ".");
  90     }
  91
  92     viewer_connection->control_sock = BT_INVALID_SOCKET;
  93 }
  94
  95 /*
  96  * This function receives a message from the Relay daemon.
  97  * If it received the entire message, it returns _OK,
  98  * If it's interrupted, it returns _INTERRUPTED,
  99  * otherwise, it returns _ERROR.
 100  */
 101 static enum lttng_live_viewer_status
 102 lttng_live_recv(struct live_viewer_connection *viewer_connection, void *buf, size_t len)
 103 {
 104     ssize_t received;
 105     size_t total_received = 0, to_receive = len;
 106     struct lttng_live_msg_iter *lttng_live_msg_iter = viewer_connection->lttng_live_msg_iter;
 107     BT_SOCKET sock = viewer_connection->control_sock;
 108
 109     /*
 110      * Receive a message from the Relay.
 111      */
 112     do {
 113         received = bt_socket_recv(sock, (char *) buf + total_received, to_receive, 0);
 114         if (received == BT_SOCKET_ERROR) {
 115             if (bt_socket_interrupted()) {
 116                 if (lttng_live_graph_is_canceled(lttng_live_msg_iter)) {
 117                     /*
 118                      * This interruption was due to a
 119                      * SIGINT and the graph is being torn
 120                      * down.
 121                      */
 122                     lttng_live_msg_iter->was_interrupted = true;
 123                     return LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED;
 124                 } else {
 125                     /*
 126                      * A signal was received, but the graph
 127                      * is not being torn down. Carry on.
 128                      */
 129                     continue;
 130                 }
 131             } else {
 132                 /*
 133                  * For any other types of socket error, close
 134                  * the socket and return an error.
 135                  */
 136                 LTTNG_LIVE_CPPLOGE_APPEND_CAUSE_ERRNO("Error receiving from Relay", ".");
 137
 138                 viewer_connection_close_socket(viewer_connection);
 139                 return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 140             }
 141         } else if (received == 0) {
 142             /*
 143              * The recv() call returned 0. This means the
 144              * connection was orderly shutdown from the other peer.
 145              * If that happens when we are trying to receive
 146              * a message from it, it means something when wrong.
 147              * Close the socket and return an error.
 148              */
 149             BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 150                                          "Remote side has closed connection");
 151             viewer_connection_close_socket(viewer_connection);
 152             return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 153         }
 154
 155         BT_ASSERT(received <= to_receive);
 156         total_received += received;
 157         to_receive -= received;
 158
 159     } while (to_receive > 0);
 160
 161     BT_ASSERT(total_received == len);
 162     return LTTNG_LIVE_VIEWER_STATUS_OK;
 163 }
 164
 165 /*
 166  * This function sends a message to the Relay daemon.
 167  * If it send the message, it returns _OK,
 168  * If it's interrupted, it returns _INTERRUPTED,
 169  * otherwise, it returns _ERROR.
 170  */
 171 static enum lttng_live_viewer_status
 172 lttng_live_send(struct live_viewer_connection *viewer_connection, const void *buf, size_t len)
 173 {
 174     struct lttng_live_msg_iter *lttng_live_msg_iter = viewer_connection->lttng_live_msg_iter;
 175     BT_SOCKET sock = viewer_connection->control_sock;
 176     size_t to_send = len;
 177     ssize_t total_sent = 0;
 178
 179     do {
 180         ssize_t sent = bt_socket_send_nosigpipe(sock, (char *) buf + total_sent, to_send);
 181         if (sent == BT_SOCKET_ERROR) {
 182             if (bt_socket_interrupted()) {
 183                 if (lttng_live_graph_is_canceled(lttng_live_msg_iter)) {
 184                     /*
 185                      * This interruption was a SIGINT and
 186                      * the graph is being teared down.
 187                      */
 188                     lttng_live_msg_iter->was_interrupted = true;
 189                     return LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED;
 190                 } else {
 191                     /*
 192                      * A signal was received, but the graph
 193                      * is not being teared down. Carry on.
 194                      */
 195                     continue;
 196                 }
 197             } else {
 198                 /*
 199                  * For any other types of socket error, close
 200                  * the socket and return an error.
 201                  */
 202                 LTTNG_LIVE_CPPLOGE_APPEND_CAUSE_ERRNO("Error sending to Relay", ".");
 203
 204                 viewer_connection_close_socket(viewer_connection);
 205                 return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 206             }
 207         }
 208
 209         BT_ASSERT(sent <= to_send);
 210         total_sent += sent;
 211         to_send -= sent;
 212
 213     } while (to_send > 0);
 214
 215     BT_ASSERT(total_sent == len);
 216     return LTTNG_LIVE_VIEWER_STATUS_OK;
 217 }
 218
 219 static int parse_url(struct live_viewer_connection *viewer_connection)
 220 {
 221     char error_buf[256] = {0};
 222     struct bt_common_lttng_live_url_parts lttng_live_url_parts = {};
 223     bt_common_lttng_live_url_parts_deleter partsDeleter {lttng_live_url_parts};
 224
 225     if (viewer_connection->url.empty()) {
 226         return -1;
 227     }
 228
 229     lttng_live_url_parts = bt_common_parse_lttng_live_url(viewer_connection->url.c_str(), error_buf,
 230                                                           sizeof(error_buf));
 231     if (!lttng_live_url_parts.proto) {
 232         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Invalid LTTng live URL format: {}",
 233                                      error_buf);
 234         return -1;
 235     }
 236     viewer_connection->proto.reset(lttng_live_url_parts.proto);
 237     lttng_live_url_parts.proto = NULL;
 238
 239     viewer_connection->relay_hostname.reset(lttng_live_url_parts.hostname);
 240     lttng_live_url_parts.hostname = NULL;
 241
 242     if (lttng_live_url_parts.port >= 0) {
 243         viewer_connection->port = lttng_live_url_parts.port;
 244     } else {
 245         viewer_connection->port = LTTNG_DEFAULT_NETWORK_VIEWER_PORT;
 246     }
 247
 248     viewer_connection->target_hostname.reset(lttng_live_url_parts.target_hostname);
 249     lttng_live_url_parts.target_hostname = NULL;
 250
 251     if (lttng_live_url_parts.session_name) {
 252         viewer_connection->session_name.reset(lttng_live_url_parts.session_name);
 253         lttng_live_url_parts.session_name = NULL;
 254     }
 255
 256     return 0;
 257 }
 258
 259 static enum lttng_live_viewer_status
 260 lttng_live_handshake(struct live_viewer_connection *viewer_connection)
 261 {
 262     struct lttng_viewer_cmd cmd;
 263     struct lttng_viewer_connect connect;
 264     enum lttng_live_viewer_status status;
 265     const size_t cmd_buf_len = sizeof(cmd) + sizeof(connect);
 266     char cmd_buf[cmd_buf_len];
 267
 268     BT_CPPLOGD_SPEC(viewer_connection->logger,
 269                     "Handshaking with the relay daemon: cmd={}, major-version={}, minor-version={}",
 270                     LTTNG_VIEWER_CONNECT, LTTNG_LIVE_MAJOR, LTTNG_LIVE_MINOR);
 271
 272     cmd.cmd = htobe32(LTTNG_VIEWER_CONNECT);
 273     cmd.data_size = htobe64((uint64_t) sizeof(connect));
 274     cmd.cmd_version = htobe32(0);
 275
 276     connect.viewer_session_id = -1ULL; /* will be set on recv */
 277     connect.major = htobe32(LTTNG_LIVE_MAJOR);
 278     connect.minor = htobe32(LTTNG_LIVE_MINOR);
 279     connect.type = htobe32(LTTNG_VIEWER_CLIENT_COMMAND);
 280
 281     /*
 282      * Merge the cmd and connection request to prevent a write-write
 283      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
 284      * second write to be performed quickly in presence of Nagle's algorithm
 285      */
 286     memcpy(cmd_buf, &cmd, sizeof(cmd));
 287     memcpy(cmd_buf + sizeof(cmd), &connect, sizeof(connect));
 288
 289     status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
 290     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 291         viewer_handle_send_status(status, "viewer connect command");
 292         return status;
 293     }
 294
 295     status = lttng_live_recv(viewer_connection, &connect, sizeof(connect));
 296     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 297         viewer_handle_recv_status(status, "viewer connect reply");
 298         return status;
 299     }
 300
 301     BT_CPPLOGI_SPEC(viewer_connection->logger, "Received viewer session ID : {}",
 302                     (uint64_t) be64toh(connect.viewer_session_id));
 303     BT_CPPLOGI_SPEC(viewer_connection->logger, "Relayd version : {}.{}", be32toh(connect.major),
 304                     be32toh(connect.minor));
 305
 306     if (LTTNG_LIVE_MAJOR != be32toh(connect.major)) {
 307         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 308                                      "Incompatible lttng-relayd protocol");
 309         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 310     }
 311     /* Use the smallest protocol version implemented. */
 312     if (LTTNG_LIVE_MINOR > be32toh(connect.minor)) {
 313         viewer_connection->minor = be32toh(connect.minor);
 314     } else {
 315         viewer_connection->minor = LTTNG_LIVE_MINOR;
 316     }
 317     viewer_connection->major = LTTNG_LIVE_MAJOR;
 318
 319     return LTTNG_LIVE_VIEWER_STATUS_OK;
 320 }
 321
 322 static enum lttng_live_viewer_status
 323 lttng_live_connect_viewer(struct live_viewer_connection *viewer_connection)
 324 {
 325     struct hostent *host;
 326     struct sockaddr_in server_addr;
 327     enum lttng_live_viewer_status status;
 328
 329     if (parse_url(viewer_connection)) {
 330         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Failed to parse URL");
 331         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 332     }
 333
 334     BT_CPPLOGD_SPEC(
 335         viewer_connection->logger,
 336         "Connecting to hostname : {}, port : {}, target hostname : {}, session name : {}, proto : {}",
 337         viewer_connection->relay_hostname->str, viewer_connection->port,
 338         !viewer_connection->target_hostname ? "<none>" : viewer_connection->target_hostname->str,
 339         !viewer_connection->session_name ? "<none>" : viewer_connection->session_name->str,
 340         viewer_connection->proto->str);
 341
 342     host = gethostbyname(viewer_connection->relay_hostname->str);
 343     if (!host) {
 344         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 345                                      "Cannot lookup hostname: hostname=\"{}\"",
 346                                      viewer_connection->relay_hostname->str);
 347         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 348     }
 349
 350     if ((viewer_connection->control_sock = socket(AF_INET, SOCK_STREAM, 0)) == BT_INVALID_SOCKET) {
 351         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Socket creation failed: {}",
 352                                      bt_socket_errormsg());
 353         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 354     }
 355
 356     server_addr.sin_family = AF_INET;
 357     server_addr.sin_port = htons(viewer_connection->port);
 358     server_addr.sin_addr = *((struct in_addr *) host->h_addr);
 359     memset(&(server_addr.sin_zero), 0, 8);
 360
 361     if (connect(viewer_connection->control_sock, (struct sockaddr *) &server_addr,
 362                 sizeof(struct sockaddr)) == BT_SOCKET_ERROR) {
 363         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Connection failed: {}",
 364                                      bt_socket_errormsg());
 365         viewer_connection_close_socket(viewer_connection);
 366         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 367     }
 368
 369     status = lttng_live_handshake(viewer_connection);
 370
 371     /*
 372      * Only print error and append cause in case of error. not in case of
 373      * interruption.
 374      */
 375     if (status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
 376         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Viewer handshake failed");
 377         viewer_connection_close_socket(viewer_connection);
 378         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 379     } else if (status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
 380         return LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED;
 381     }
 382
 383     return LTTNG_LIVE_VIEWER_STATUS_OK;
 384 }
 385
 386 static int list_update_session(const bt2::ArrayValue results,
 387                                const struct lttng_viewer_session *session, bool *_found,
 388                                struct live_viewer_connection *viewer_connection)
 389 {
 390     bool found = false;
 391
 392     for (const auto value : results) {
 393         const auto map = value.asMap();
 394         const auto hostnameVal = map["target-hostname"];
 395
 396         if (!hostnameVal) {
 397             BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 398                                          "Error borrowing \"target-hostname\" entry.");
 399             return -1;
 400         }
 401
 402         const auto sessionNameVal = map["session-name"];
 403
 404         if (!sessionNameVal) {
 405             BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 406                                          "Error borrowing \"session-name\" entry.");
 407             return -1;
 408         }
 409
 410         const auto hostname_str = hostnameVal->asString().value();
 411         const auto session_name_str = sessionNameVal->asString().value();
 412
 413         if (strcmp(session->hostname, hostname_str) == 0 &&
 414             strcmp(session->session_name, session_name_str) == 0) {
 415             uint32_t streams = be32toh(session->streams);
 416             uint32_t clients = be32toh(session->clients);
 417
 418             found = true;
 419
 420             const auto streamCountVal = map["stream-count"];
 421
 422             if (!streamCountVal) {
 423                 BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 424                                              "Error borrowing \"stream-count\" entry.");
 425                 return -1;
 426             }
 427
 428             auto val = streamCountVal->asUnsignedInteger().value();
 429
 430             /* sum */
 431             val += streams;
 432             streamCountVal->asUnsignedInteger().value(val);
 433
 434             const auto clientCountVal = map["client-count"];
 435
 436             if (!clientCountVal) {
 437                 BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 438                                              "Error borrowing \"client-count\" entry.");
 439                 return -1;
 440             }
 441
 442             val = clientCountVal->asUnsignedInteger().value();
 443
 444             /* max */
 445             val = std::max<uint64_t>(clients, val);
 446             clientCountVal->asUnsignedInteger().value(val);
 447         }
 448
 449         if (found) {
 450             break;
 451         }
 452     }
 453
 454     *_found = found;
 455     return 0;
 456 }
 457
 458 static int list_append_session(const bt2::ArrayValue results, const std::string& base_url,
 459                                const struct lttng_viewer_session *session,
 460                                struct live_viewer_connection *viewer_connection)
 461 {
 462     int ret = 0;
 463     bool found = false;
 464
 465     /*
 466      * If the session already exists, add the stream count to it,
 467      * and do max of client counts.
 468      */
 469     ret = list_update_session(results, session, &found, viewer_connection);
 470     if (ret || found) {
 471         return ret;
 472     }
 473
 474     const auto map = bt2::MapValue::create();
 475
 476     if (base_url.empty()) {
 477         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Error: base_url empty.");
 478         return -1;
 479     }
 480
 481     /*
 482      * key = "url",
 483      * value = <string>,
 484      */
 485     map->insert("url",
 486                 fmt::format("{}/host/{}/{}", base_url, session->hostname, session->session_name));
 487
 488     /*
 489      * key = "target-hostname",
 490      * value = <string>,
 491      */
 492     map->insert("target-hostname", session->hostname);
 493
 494     /*
 495      * key = "session-name",
 496      * value = <string>,
 497      */
 498     map->insert("session-name", session->session_name);
 499
 500     /*
 501      * key = "timer-us",
 502      * value = <integer>,
 503      */
 504     {
 505         uint32_t live_timer = be32toh(session->live_timer);
 506
 507         map->insert("timer-us", (uint64_t) live_timer);
 508     }
 509
 510     /*
 511      * key = "stream-count",
 512      * value = <integer>,
 513      */
 514     {
 515         uint32_t streams = be32toh(session->streams);
 516
 517         map->insert("stream-count", (uint64_t) streams);
 518     }
 519
 520     /*
 521      * key = "client-count",
 522      * value = <integer>,
 523      */
 524     {
 525         uint32_t clients = be32toh(session->clients);
 526
 527         map->insert("client-count", (uint64_t) clients);
 528     }
 529
 530     results.append(*map);
 531     return 0;
 532 }
 533
 534 /*
 535  * Data structure returned:
 536  *
 537  * {
 538  *   <array> = {
 539  *     [n] = {
 540  *       <map> = {
 541  *         {
 542  *           key = "url",
 543  *           value = <string>,
 544  *         },
 545  *         {
 546  *           key = "target-hostname",
 547  *           value = <string>,
 548  *         },
 549  *         {
 550  *           key = "session-name",
 551  *           value = <string>,
 552  *         },
 553  *         {
 554  *           key = "timer-us",
 555  *           value = <integer>,
 556  *         },
 557  *         {
 558  *           key = "stream-count",
 559  *           value = <integer>,
 560  *         },
 561  *         {
 562  *           key = "client-count",
 563  *           value = <integer>,
 564  *         },
 565  *       },
 566  *     }
 567  *   }
 568  */
 569
 570 bt2::Value::Shared
 571 live_viewer_connection_list_sessions(struct live_viewer_connection *viewer_connection)
 572 {
 573     enum lttng_live_viewer_status viewer_status;
 574     struct lttng_viewer_cmd cmd;
 575     struct lttng_viewer_list_sessions list;
 576     uint32_t i, sessions_count;
 577     auto result = bt2::ArrayValue::create();
 578
 579     BT_CPPLOGD_SPEC(viewer_connection->logger, "Requesting list of sessions: cmd={}",
 580                     LTTNG_VIEWER_LIST_SESSIONS);
 581
 582     cmd.cmd = htobe32(LTTNG_VIEWER_LIST_SESSIONS);
 583     cmd.data_size = htobe64((uint64_t) 0);
 584     cmd.cmd_version = htobe32(0);
 585
 586     viewer_status = lttng_live_send(viewer_connection, &cmd, sizeof(cmd));
 587     if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
 588         BT_CPPLOGE_APPEND_CAUSE_AND_THROW_SPEC(viewer_connection->logger, bt2::Error,
 589                                                "Error sending list sessions command");
 590     } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
 591         throw bt2c::TryAgain {};
 592     }
 593
 594     viewer_status = lttng_live_recv(viewer_connection, &list, sizeof(list));
 595     if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
 596         BT_CPPLOGE_APPEND_CAUSE_AND_THROW_SPEC(viewer_connection->logger, bt2::Error,
 597                                                "Error receiving session list");
 598     } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
 599         throw bt2c::TryAgain {};
 600     }
 601
 602     sessions_count = be32toh(list.sessions_count);
 603     for (i = 0; i < sessions_count; i++) {
 604         struct lttng_viewer_session lsession;
 605
 606         viewer_status = lttng_live_recv(viewer_connection, &lsession, sizeof(lsession));
 607         if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
 608             BT_CPPLOGE_APPEND_CAUSE_AND_THROW_SPEC(viewer_connection->logger, bt2::Error,
 609                                                    "Error receiving session:");
 610         } else if (viewer_status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
 611             throw bt2c::TryAgain {};
 612         }
 613
 614         lsession.hostname[LTTNG_VIEWER_HOST_NAME_MAX - 1] = '\0';
 615         lsession.session_name[LTTNG_VIEWER_NAME_MAX - 1] = '\0';
 616         if (list_append_session(*result, viewer_connection->url, &lsession, viewer_connection)) {
 617             BT_CPPLOGE_APPEND_CAUSE_AND_THROW_SPEC(viewer_connection->logger, bt2::Error,
 618                                                    "Error appending session");
 619         }
 620     }
 621
 622     return result;
 623 }
 624
 625 static enum lttng_live_viewer_status
 626 lttng_live_query_session_ids(struct lttng_live_msg_iter *lttng_live_msg_iter)
 627 {
 628     struct lttng_viewer_cmd cmd;
 629     struct lttng_viewer_list_sessions list;
 630     struct lttng_viewer_session lsession;
 631     uint32_t i, sessions_count;
 632     uint64_t session_id;
 633     enum lttng_live_viewer_status status;
 634     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
 635
 636     BT_CPPLOGD_SPEC(viewer_connection->logger,
 637                     "Asking the relay daemon for the list of sessions: cmd={}",
 638                     LTTNG_VIEWER_LIST_SESSIONS);
 639
 640     cmd.cmd = htobe32(LTTNG_VIEWER_LIST_SESSIONS);
 641     cmd.data_size = htobe64((uint64_t) 0);
 642     cmd.cmd_version = htobe32(0);
 643
 644     status = lttng_live_send(viewer_connection, &cmd, sizeof(cmd));
 645     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 646         viewer_handle_send_status(status, "list sessions command");
 647         return status;
 648     }
 649
 650     status = lttng_live_recv(viewer_connection, &list, sizeof(list));
 651     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 652         viewer_handle_recv_status(status, "session list reply");
 653         return status;
 654     }
 655
 656     sessions_count = be32toh(list.sessions_count);
 657     for (i = 0; i < sessions_count; i++) {
 658         status = lttng_live_recv(viewer_connection, &lsession, sizeof(lsession));
 659         if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 660             viewer_handle_recv_status(status, "session reply");
 661             return status;
 662         }
 663         lsession.hostname[LTTNG_VIEWER_HOST_NAME_MAX - 1] = '\0';
 664         lsession.session_name[LTTNG_VIEWER_NAME_MAX - 1] = '\0';
 665         session_id = be64toh(lsession.id);
 666
 667         BT_CPPLOGI_SPEC(viewer_connection->logger,
 668                         "Adding session to internal list: "
 669                         "session-id={}, hostname=\"{}\", session-name=\"{}\"",
 670                         session_id, lsession.hostname, lsession.session_name);
 671
 672         if ((strncmp(lsession.session_name, viewer_connection->session_name->str,
 673                      LTTNG_VIEWER_NAME_MAX) == 0) &&
 674             (strncmp(lsession.hostname, viewer_connection->target_hostname->str,
 675                      LTTNG_VIEWER_HOST_NAME_MAX) == 0)) {
 676             if (lttng_live_add_session(lttng_live_msg_iter, session_id, lsession.hostname,
 677                                        lsession.session_name)) {
 678                 BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 679                                              "Failed to add live session");
 680                 return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 681             }
 682         }
 683     }
 684
 685     return LTTNG_LIVE_VIEWER_STATUS_OK;
 686 }
 687
 688 enum lttng_live_viewer_status
 689 lttng_live_create_viewer_session(struct lttng_live_msg_iter *lttng_live_msg_iter)
 690 {
 691     struct lttng_viewer_cmd cmd;
 692     struct lttng_viewer_create_session_response resp;
 693     enum lttng_live_viewer_status status;
 694     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
 695
 696     BT_CPPLOGD_SPEC(viewer_connection->logger, "Creating a viewer session: cmd={}",
 697                     LTTNG_VIEWER_CREATE_SESSION);
 698
 699     cmd.cmd = htobe32(LTTNG_VIEWER_CREATE_SESSION);
 700     cmd.data_size = htobe64((uint64_t) 0);
 701     cmd.cmd_version = htobe32(0);
 702
 703     status = lttng_live_send(viewer_connection, &cmd, sizeof(cmd));
 704     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 705         viewer_handle_send_status(status, "create session command");
 706         return status;
 707     }
 708
 709     status = lttng_live_recv(viewer_connection, &resp, sizeof(resp));
 710     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 711         viewer_handle_recv_status(status, "create session reply");
 712         return status;
 713     }
 714
 715     if (be32toh(resp.status) != LTTNG_VIEWER_CREATE_SESSION_OK) {
 716         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Error creating viewer session");
 717         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 718     }
 719
 720     status = lttng_live_query_session_ids(lttng_live_msg_iter);
 721     if (status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
 722         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 723                                      "Failed to query live viewer session ids");
 724         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 725     } else if (status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
 726         return LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED;
 727     }
 728
 729     return LTTNG_LIVE_VIEWER_STATUS_OK;
 730 }
 731
 732 static enum lttng_live_viewer_status receive_streams(struct lttng_live_session *session,
 733                                                      uint32_t stream_count,
 734                                                      bt_self_message_iterator *self_msg_iter)
 735 {
 736     uint32_t i;
 737     struct lttng_live_msg_iter *lttng_live_msg_iter = session->lttng_live_msg_iter;
 738     enum lttng_live_viewer_status status;
 739     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
 740
 741     BT_CPPLOGI_SPEC(viewer_connection->logger, "Getting {} new streams", stream_count);
 742     for (i = 0; i < stream_count; i++) {
 743         struct lttng_viewer_stream stream;
 744         struct lttng_live_stream_iterator *live_stream;
 745         uint64_t stream_id;
 746         uint64_t ctf_trace_id;
 747
 748         status = lttng_live_recv(viewer_connection, &stream, sizeof(stream));
 749         if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 750             viewer_handle_recv_status(status, "stream reply");
 751             return status;
 752         }
 753         stream.path_name[LTTNG_VIEWER_PATH_MAX - 1] = '\0';
 754         stream.channel_name[LTTNG_VIEWER_NAME_MAX - 1] = '\0';
 755         stream_id = be64toh(stream.id);
 756         ctf_trace_id = be64toh(stream.ctf_trace_id);
 757
 758         if (stream.metadata_flag) {
 759             BT_CPPLOGI_SPEC(viewer_connection->logger, "    metadata stream {} : {}/{}", stream_id,
 760                             stream.path_name, stream.channel_name);
 761             if (lttng_live_metadata_create_stream(session, ctf_trace_id, stream_id)) {
 762                 BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 763                                              "Error creating metadata stream");
 764                 return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 765             }
 766             session->lazy_stream_msg_init = true;
 767         } else {
 768             BT_CPPLOGI_SPEC(viewer_connection->logger, "    stream {} : {}/{}", stream_id,
 769                             stream.path_name, stream.channel_name);
 770             live_stream =
 771                 lttng_live_stream_iterator_create(session, ctf_trace_id, stream_id, self_msg_iter);
 772             if (!live_stream) {
 773                 BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Error creating stream");
 774                 return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 775             }
 776         }
 777     }
 778
 779     return LTTNG_LIVE_VIEWER_STATUS_OK;
 780 }
 781
 782 enum lttng_live_viewer_status lttng_live_session_attach(struct lttng_live_session *session,
 783                                                         bt_self_message_iterator *self_msg_iter)
 784 {
 785     struct lttng_viewer_cmd cmd;
 786     enum lttng_live_viewer_status status;
 787     struct lttng_viewer_attach_session_request rq;
 788     struct lttng_viewer_attach_session_response rp;
 789     struct lttng_live_msg_iter *lttng_live_msg_iter = session->lttng_live_msg_iter;
 790     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
 791     uint64_t session_id = session->id;
 792     uint32_t streams_count;
 793     const size_t cmd_buf_len = sizeof(cmd) + sizeof(rq);
 794     char cmd_buf[cmd_buf_len];
 795
 796     BT_CPPLOGD_SPEC(viewer_connection->logger,
 797                     "Attaching to session: cmd={}, session-id={}, seek={}",
 798                     LTTNG_VIEWER_ATTACH_SESSION, session_id, LTTNG_VIEWER_SEEK_LAST);
 799
 800     cmd.cmd = htobe32(LTTNG_VIEWER_ATTACH_SESSION);
 801     cmd.data_size = htobe64((uint64_t) sizeof(rq));
 802     cmd.cmd_version = htobe32(0);
 803
 804     memset(&rq, 0, sizeof(rq));
 805     rq.session_id = htobe64(session_id);
 806     // TODO: add cmd line parameter to select seek beginning
 807     // rq.seek = htobe32(LTTNG_VIEWER_SEEK_BEGINNING);
 808     rq.seek = htobe32(LTTNG_VIEWER_SEEK_LAST);
 809
 810     /*
 811      * Merge the cmd and connection request to prevent a write-write
 812      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
 813      * second write to be performed quickly in presence of Nagle's algorithm.
 814      */
 815     memcpy(cmd_buf, &cmd, sizeof(cmd));
 816     memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
 817     status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
 818     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 819         viewer_handle_send_status(status, "attach session command");
 820         return status;
 821     }
 822
 823     status = lttng_live_recv(viewer_connection, &rp, sizeof(rp));
 824     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 825         viewer_handle_recv_status(status, "attach session reply");
 826         return status;
 827     }
 828
 829     streams_count = be32toh(rp.streams_count);
 830     switch (be32toh(rp.status)) {
 831     case LTTNG_VIEWER_ATTACH_OK:
 832         break;
 833     case LTTNG_VIEWER_ATTACH_UNK:
 834         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Session id {} is unknown",
 835                                      session_id);
 836         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 837     case LTTNG_VIEWER_ATTACH_ALREADY:
 838         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
 839                                      "There is already a viewer attached to this session");
 840         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 841     case LTTNG_VIEWER_ATTACH_NOT_LIVE:
 842         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Not a live session");
 843         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 844     case LTTNG_VIEWER_ATTACH_SEEK_ERR:
 845         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Wrong seek parameter");
 846         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 847     default:
 848         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Unknown attach return code {}",
 849                                      be32toh(rp.status));
 850         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 851     }
 852
 853     /* We receive the initial list of streams. */
 854     status = receive_streams(session, streams_count, self_msg_iter);
 855     switch (status) {
 856     case LTTNG_LIVE_VIEWER_STATUS_OK:
 857         break;
 858     case LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED:
 859         return status;
 860     case LTTNG_LIVE_VIEWER_STATUS_ERROR:
 861         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Error receiving streams");
 862         return status;
 863     default:
 864         bt_common_abort();
 865     }
 866
 867     session->attached = true;
 868     session->new_streams_needed = false;
 869
 870     return LTTNG_LIVE_VIEWER_STATUS_OK;
 871 }
 872
 873 enum lttng_live_viewer_status lttng_live_session_detach(struct lttng_live_session *session)
 874 {
 875     struct lttng_viewer_cmd cmd;
 876     enum lttng_live_viewer_status status;
 877     struct lttng_viewer_detach_session_request rq;
 878     struct lttng_viewer_detach_session_response rp;
 879     struct lttng_live_msg_iter *lttng_live_msg_iter = session->lttng_live_msg_iter;
 880     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
 881     uint64_t session_id = session->id;
 882     const size_t cmd_buf_len = sizeof(cmd) + sizeof(rq);
 883     char cmd_buf[cmd_buf_len];
 884
 885     /*
 886      * The session might already be detached and the viewer socket might
 887      * already been closed. This happens when calling this function when
 888      * tearing down the graph after an error.
 889      */
 890     if (!session->attached || viewer_connection->control_sock == BT_INVALID_SOCKET) {
 891         return LTTNG_LIVE_VIEWER_STATUS_OK;
 892     }
 893
 894     BT_CPPLOGD_SPEC(viewer_connection->logger, "Detaching from session: cmd={}, session-id={}",
 895                     LTTNG_VIEWER_DETACH_SESSION, session_id);
 896
 897     cmd.cmd = htobe32(LTTNG_VIEWER_DETACH_SESSION);
 898     cmd.data_size = htobe64((uint64_t) sizeof(rq));
 899     cmd.cmd_version = htobe32(0);
 900
 901     memset(&rq, 0, sizeof(rq));
 902     rq.session_id = htobe64(session_id);
 903
 904     /*
 905      * Merge the cmd and connection request to prevent a write-write
 906      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
 907      * second write to be performed quickly in presence of Nagle's algorithm.
 908      */
 909     memcpy(cmd_buf, &cmd, sizeof(cmd));
 910     memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
 911     status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
 912     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 913         viewer_handle_send_status(status, "detach session command");
 914         return status;
 915     }
 916
 917     status = lttng_live_recv(viewer_connection, &rp, sizeof(rp));
 918     if (status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 919         viewer_handle_recv_status(status, "detach session reply");
 920         return status;
 921     }
 922
 923     switch (be32toh(rp.status)) {
 924     case LTTNG_VIEWER_DETACH_SESSION_OK:
 925         break;
 926     case LTTNG_VIEWER_DETACH_SESSION_UNK:
 927         BT_CPPLOGW_SPEC(viewer_connection->logger, "Session id {} is unknown", session_id);
 928         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 929     case LTTNG_VIEWER_DETACH_SESSION_ERR:
 930         BT_CPPLOGW_SPEC(viewer_connection->logger, "Error detaching session id {}", session_id);
 931         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 932     default:
 933         BT_CPPLOGE_SPEC(viewer_connection->logger, "Unknown detach return code {}",
 934                         be32toh(rp.status));
 935         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
 936     }
 937
 938     session->attached = false;
 939
 940     return LTTNG_LIVE_VIEWER_STATUS_OK;
 941 }
 942
 943 enum lttng_live_get_one_metadata_status
 944 lttng_live_get_one_metadata_packet(struct lttng_live_trace *trace, std::vector<char>& buf)
 945 {
 946     uint64_t len = 0;
 947     enum lttng_live_viewer_status viewer_status;
 948     struct lttng_viewer_cmd cmd;
 949     struct lttng_viewer_get_metadata rq;
 950     struct lttng_viewer_metadata_packet rp;
 951     std::vector<char> data;
 952     struct lttng_live_session *session = trace->session;
 953     struct lttng_live_msg_iter *lttng_live_msg_iter = session->lttng_live_msg_iter;
 954     struct lttng_live_metadata *metadata = trace->metadata.get();
 955     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
 956     const size_t cmd_buf_len = sizeof(cmd) + sizeof(rq);
 957     char cmd_buf[cmd_buf_len];
 958
 959     BT_CPPLOGD_SPEC(viewer_connection->logger,
 960                     "Requesting new metadata for trace:"
 961                     "cmd={}, trace-id={}, metadata-stream-id={}",
 962                     LTTNG_VIEWER_GET_METADATA, trace->id, metadata->stream_id);
 963
 964     rq.stream_id = htobe64(metadata->stream_id);
 965     cmd.cmd = htobe32(LTTNG_VIEWER_GET_METADATA);
 966     cmd.data_size = htobe64((uint64_t) sizeof(rq));
 967     cmd.cmd_version = htobe32(0);
 968
 969     /*
 970      * Merge the cmd and connection request to prevent a write-write
 971      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
 972      * second write to be performed quickly in presence of Nagle's algorithm.
 973      */
 974     memcpy(cmd_buf, &cmd, sizeof(cmd));
 975     memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
 976     viewer_status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
 977     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 978         viewer_handle_send_status(viewer_status, "get metadata command");
 979         return (lttng_live_get_one_metadata_status) viewer_status;
 980     }
 981
 982     viewer_status = lttng_live_recv(viewer_connection, &rp, sizeof(rp));
 983     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
 984         viewer_handle_recv_status(viewer_status, "get metadata reply");
 985         return (lttng_live_get_one_metadata_status) viewer_status;
 986     }
 987
 988     switch (be32toh(rp.status)) {
 989     case LTTNG_VIEWER_METADATA_OK:
 990         BT_CPPLOGD_SPEC(viewer_connection->logger, "Received get_metadata response: ok");
 991         break;
 992     case LTTNG_VIEWER_NO_NEW_METADATA:
 993         BT_CPPLOGD_SPEC(viewer_connection->logger, "Received get_metadata response: no new");
 994         return LTTNG_LIVE_GET_ONE_METADATA_STATUS_END;
 995     case LTTNG_VIEWER_METADATA_ERR:
 996         /*
 997              * The Relayd cannot find this stream id. Maybe its
 998              * gone already. This can happen in short lived UST app
 999              * in a per-pid session.
1000              */
1001         BT_CPPLOGD_SPEC(viewer_connection->logger, "Received get_metadata response: error");
1002         return LTTNG_LIVE_GET_ONE_METADATA_STATUS_CLOSED;
1003     default:
1004         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
1005                                      "Received get_metadata response: unknown");
1006         return LTTNG_LIVE_GET_ONE_METADATA_STATUS_ERROR;
1007     }
1008
1009     len = be64toh(rp.len);
1010     if (len == 0) {
1011         /*
1012          * We received a `LTTNG_VIEWER_METADATA_OK` with a packet
1013          * length of 0. This means we must try again. This scenario
1014          * arises when a clear command is performed on an lttng session.
1015          */
1016         BT_CPPLOGD_SPEC(
1017             viewer_connection->logger,
1018             "Expecting a metadata packet of size 0. Retry to get a packet from the relay.");
1019         return LTTNG_LIVE_GET_ONE_METADATA_STATUS_OK;
1020     }
1021
1022     BT_CPPLOGD_SPEC(viewer_connection->logger, "Writing {} bytes to metadata", len);
1023     if (len <= 0) {
1024         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Erroneous response length");
1025         return LTTNG_LIVE_GET_ONE_METADATA_STATUS_ERROR;
1026     }
1027
1028     data.resize(len);
1029
1030     viewer_status = lttng_live_recv(viewer_connection, data.data(), len);
1031     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1032         viewer_handle_recv_status(viewer_status, "get metadata packet");
1033         return (lttng_live_get_one_metadata_status) viewer_status;
1034     }
1035
1036     /*
1037      * Write the metadata to the file handle.
1038      */
1039     buf.insert(buf.end(), data.begin(), data.end());
1040
1041     return LTTNG_LIVE_GET_ONE_METADATA_STATUS_OK;
1042 }
1043
1044 /*
1045  * Assign the fields from a lttng_viewer_index to a packet_index.
1046  */
1047 static void lttng_index_to_packet_index(struct lttng_viewer_index *lindex,
1048                                         struct packet_index *pindex)
1049 {
1050     BT_ASSERT(lindex);
1051     BT_ASSERT(pindex);
1052
1053     pindex->offset = be64toh(lindex->offset);
1054     pindex->packet_size = be64toh(lindex->packet_size);
1055     pindex->content_size = be64toh(lindex->content_size);
1056     pindex->ts_cycles.timestamp_begin = be64toh(lindex->timestamp_begin);
1057     pindex->ts_cycles.timestamp_end = be64toh(lindex->timestamp_end);
1058     pindex->events_discarded = be64toh(lindex->events_discarded);
1059 }
1060
1061 static void lttng_live_need_new_streams(struct lttng_live_msg_iter *lttng_live_msg_iter)
1062 {
1063     for (const auto& session : lttng_live_msg_iter->sessions) {
1064         BT_CPPLOGD_SPEC(lttng_live_msg_iter->logger,
1065                         "Marking session as needing new streams: "
1066                         "session-id={}",
1067                         session->id);
1068         session->new_streams_needed = true;
1069     }
1070 }
1071
1072 enum lttng_live_iterator_status
1073 lttng_live_get_next_index(struct lttng_live_msg_iter *lttng_live_msg_iter,
1074                           struct lttng_live_stream_iterator *stream, struct packet_index *index)
1075 {
1076     struct lttng_viewer_cmd cmd;
1077     struct lttng_viewer_get_next_index rq;
1078     enum lttng_live_viewer_status viewer_status;
1079     struct lttng_viewer_index rp;
1080     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
1081     struct lttng_live_trace *trace = stream->trace;
1082     const size_t cmd_buf_len = sizeof(cmd) + sizeof(rq);
1083     char cmd_buf[cmd_buf_len];
1084     uint32_t flags, rp_status;
1085
1086     BT_CPPLOGD_SPEC(viewer_connection->logger,
1087                     "Requesting next index for stream: cmd={}, "
1088                     "viewer-stream-id={}",
1089                     LTTNG_VIEWER_GET_NEXT_INDEX, stream->viewer_stream_id);
1090     cmd.cmd = htobe32(LTTNG_VIEWER_GET_NEXT_INDEX);
1091     cmd.data_size = htobe64((uint64_t) sizeof(rq));
1092     cmd.cmd_version = htobe32(0);
1093
1094     memset(&rq, 0, sizeof(rq));
1095     rq.stream_id = htobe64(stream->viewer_stream_id);
1096
1097     /*
1098      * Merge the cmd and connection request to prevent a write-write
1099      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
1100      * second write to be performed quickly in presence of Nagle's algorithm.
1101      */
1102     memcpy(cmd_buf, &cmd, sizeof(cmd));
1103     memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
1104
1105     viewer_status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
1106     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1107         viewer_handle_send_status(viewer_status, "get next index command");
1108         return viewer_status_to_live_iterator_status(viewer_status);
1109     }
1110
1111     viewer_status = lttng_live_recv(viewer_connection, &rp, sizeof(rp));
1112     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1113         viewer_handle_recv_status(viewer_status, "get next index reply");
1114         return viewer_status_to_live_iterator_status(viewer_status);
1115     }
1116
1117     flags = be32toh(rp.flags);
1118     rp_status = be32toh(rp.status);
1119
1120     BT_CPPLOGD_SPEC(
1121         viewer_connection->logger, "Received response from relay daemon: cmd=%s, response={}",
1122         LTTNG_VIEWER_GET_NEXT_INDEX, static_cast<lttng_viewer_next_index_return_code>(rp_status));
1123
1124     if (flags & LTTNG_VIEWER_FLAG_NEW_STREAM) {
1125         BT_CPPLOGD_SPEC(viewer_connection->logger,
1126                         "Marking all sessions as possibly needing new streams: "
1127                         "response={}, response-flag=NEW_STREAM",
1128                         static_cast<lttng_viewer_next_index_return_code>(rp_status));
1129         lttng_live_need_new_streams(lttng_live_msg_iter);
1130     }
1131
1132     switch (rp_status) {
1133     case LTTNG_VIEWER_INDEX_INACTIVE:
1134     {
1135         uint64_t ctf_stream_class_id;
1136
1137         memset(index, 0, sizeof(struct packet_index));
1138         index->ts_cycles.timestamp_end = be64toh(rp.timestamp_end);
1139         stream->current_inactivity_ts = index->ts_cycles.timestamp_end;
1140         ctf_stream_class_id = be64toh(rp.stream_id);
1141         if (stream->ctf_stream_class_id.is_set) {
1142             BT_ASSERT(stream->ctf_stream_class_id.value == ctf_stream_class_id);
1143         } else {
1144             stream->ctf_stream_class_id.value = ctf_stream_class_id;
1145             stream->ctf_stream_class_id.is_set = true;
1146         }
1147         lttng_live_stream_iterator_set_state(stream, LTTNG_LIVE_STREAM_QUIESCENT);
1148         return LTTNG_LIVE_ITERATOR_STATUS_OK;
1149     }
1150     case LTTNG_VIEWER_INDEX_OK:
1151     {
1152         uint64_t ctf_stream_class_id;
1153
1154         lttng_index_to_packet_index(&rp, index);
1155         ctf_stream_class_id = be64toh(rp.stream_id);
1156         if (stream->ctf_stream_class_id.is_set) {
1157             BT_ASSERT(stream->ctf_stream_class_id.value == ctf_stream_class_id);
1158         } else {
1159             stream->ctf_stream_class_id.value = ctf_stream_class_id;
1160             stream->ctf_stream_class_id.is_set = true;
1161         }
1162         lttng_live_stream_iterator_set_state(stream, LTTNG_LIVE_STREAM_ACTIVE_DATA);
1163
1164         if (flags & LTTNG_VIEWER_FLAG_NEW_METADATA) {
1165             BT_CPPLOGD_SPEC(viewer_connection->logger,
1166                             "Marking trace as needing new metadata: "
1167                             "response={}, response-flag=NEW_METADATA, trace-id={}",
1168                             static_cast<lttng_viewer_next_index_return_code>(rp_status), trace->id);
1169             trace->metadata_stream_state = LTTNG_LIVE_METADATA_STREAM_STATE_NEEDED;
1170         }
1171         return LTTNG_LIVE_ITERATOR_STATUS_OK;
1172         break;
1173     }
1174     case LTTNG_VIEWER_INDEX_RETRY:
1175         memset(index, 0, sizeof(struct packet_index));
1176         lttng_live_stream_iterator_set_state(stream, LTTNG_LIVE_STREAM_ACTIVE_NO_DATA);
1177         return LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
1178     case LTTNG_VIEWER_INDEX_HUP:
1179         memset(index, 0, sizeof(struct packet_index));
1180         index->offset = EOF;
1181         lttng_live_stream_iterator_set_state(stream, LTTNG_LIVE_STREAM_EOF);
1182         stream->has_stream_hung_up = true;
1183         return LTTNG_LIVE_ITERATOR_STATUS_END;
1184     case LTTNG_VIEWER_INDEX_ERR:
1185         memset(index, 0, sizeof(struct packet_index));
1186         lttng_live_stream_iterator_set_state(stream, LTTNG_LIVE_STREAM_ACTIVE_NO_DATA);
1187         return LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1188     default:
1189         BT_CPPLOGD_SPEC(viewer_connection->logger,
1190                         "Received get_next_index response: unknown value");
1191         memset(index, 0, sizeof(struct packet_index));
1192         lttng_live_stream_iterator_set_state(stream, LTTNG_LIVE_STREAM_ACTIVE_NO_DATA);
1193         return LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1194     }
1195 }
1196
1197 enum ctf_msg_iter_medium_status
1198 lttng_live_get_stream_bytes(struct lttng_live_msg_iter *lttng_live_msg_iter,
1199                             struct lttng_live_stream_iterator *stream, uint8_t *buf,
1200                             uint64_t offset, uint64_t req_len, uint64_t *recv_len)
1201 {
1202     enum lttng_live_viewer_status viewer_status;
1203     struct lttng_viewer_trace_packet rp;
1204     struct lttng_viewer_cmd cmd;
1205     struct lttng_viewer_get_packet rq;
1206     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
1207     struct lttng_live_trace *trace = stream->trace;
1208     const size_t cmd_buf_len = sizeof(cmd) + sizeof(rq);
1209     char cmd_buf[cmd_buf_len];
1210     uint32_t flags, rp_status;
1211
1212     BT_CPPLOGD_SPEC(viewer_connection->logger,
1213                     "Requesting data from stream: cmd={}, "
1214                     "offset={}, request-len={}",
1215                     LTTNG_VIEWER_GET_PACKET, offset, req_len);
1216
1217     cmd.cmd = htobe32(LTTNG_VIEWER_GET_PACKET);
1218     cmd.data_size = htobe64((uint64_t) sizeof(rq));
1219     cmd.cmd_version = htobe32(0);
1220
1221     memset(&rq, 0, sizeof(rq));
1222     rq.stream_id = htobe64(stream->viewer_stream_id);
1223     rq.offset = htobe64(offset);
1224     rq.len = htobe32(req_len);
1225
1226     /*
1227      * Merge the cmd and connection request to prevent a write-write
1228      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
1229      * second write to be performed quickly in presence of Nagle's algorithm.
1230      */
1231     memcpy(cmd_buf, &cmd, sizeof(cmd));
1232     memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
1233
1234     viewer_status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
1235     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1236         viewer_handle_send_status(viewer_status, "get data packet command");
1237         return viewer_status_to_ctf_msg_iter_medium_status(viewer_status);
1238     }
1239
1240     viewer_status = lttng_live_recv(viewer_connection, &rp, sizeof(rp));
1241     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1242         viewer_handle_recv_status(viewer_status, "get data packet reply");
1243         return viewer_status_to_ctf_msg_iter_medium_status(viewer_status);
1244     }
1245
1246     flags = be32toh(rp.flags);
1247     rp_status = be32toh(rp.status);
1248
1249     BT_CPPLOGD_SPEC(
1250         viewer_connection->logger, "Received response from relay daemon: cmd={}, response={}",
1251         LTTNG_VIEWER_GET_PACKET, static_cast<lttng_viewer_get_packet_return_code>(rp_status));
1252     switch (rp_status) {
1253     case LTTNG_VIEWER_GET_PACKET_OK:
1254         req_len = be32toh(rp.len);
1255         BT_CPPLOGD_SPEC(viewer_connection->logger,
1256                         "Got packet from relay daemon: response={}, packet-len={}",
1257                         static_cast<lttng_viewer_get_packet_return_code>(rp_status), req_len);
1258         break;
1259     case LTTNG_VIEWER_GET_PACKET_RETRY:
1260         /* Unimplemented by relay daemon */
1261         return CTF_MSG_ITER_MEDIUM_STATUS_AGAIN;
1262     case LTTNG_VIEWER_GET_PACKET_ERR:
1263         if (flags & LTTNG_VIEWER_FLAG_NEW_METADATA) {
1264             BT_CPPLOGD_SPEC(viewer_connection->logger,
1265                             "Marking trace as needing new metadata: "
1266                             "response={}, response-flag=NEW_METADATA, trace-id={}",
1267                             static_cast<lttng_viewer_get_packet_return_code>(rp_status), trace->id);
1268             trace->metadata_stream_state = LTTNG_LIVE_METADATA_STREAM_STATE_NEEDED;
1269         }
1270         if (flags & LTTNG_VIEWER_FLAG_NEW_STREAM) {
1271             BT_CPPLOGD_SPEC(viewer_connection->logger,
1272                             "Marking all sessions as possibly needing new streams: "
1273                             "response={}, response-flag=NEW_STREAM",
1274                             static_cast<lttng_viewer_get_packet_return_code>(rp_status));
1275             lttng_live_need_new_streams(lttng_live_msg_iter);
1276         }
1277         if (flags & (LTTNG_VIEWER_FLAG_NEW_METADATA | LTTNG_VIEWER_FLAG_NEW_STREAM)) {
1278             BT_CPPLOGD_SPEC(viewer_connection->logger,
1279                             "Reply with any one flags set means we should retry: response={}",
1280                             static_cast<lttng_viewer_get_packet_return_code>(rp_status));
1281             return CTF_MSG_ITER_MEDIUM_STATUS_AGAIN;
1282         }
1283         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
1284                                      "Received get_data_packet response: error");
1285         return CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
1286     case LTTNG_VIEWER_GET_PACKET_EOF:
1287         return CTF_MSG_ITER_MEDIUM_STATUS_EOF;
1288     default:
1289         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
1290                                      "Received get_data_packet response: unknown ({})", rp_status);
1291         return CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
1292     }
1293
1294     if (req_len == 0) {
1295         return CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
1296     }
1297
1298     viewer_status = lttng_live_recv(viewer_connection, buf, req_len);
1299     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1300         viewer_handle_recv_status(viewer_status, "get data packet");
1301         return viewer_status_to_ctf_msg_iter_medium_status(viewer_status);
1302     }
1303     *recv_len = req_len;
1304
1305     return CTF_MSG_ITER_MEDIUM_STATUS_OK;
1306 }
1307
1308 /*
1309  * Request new streams for a session.
1310  */
1311 enum lttng_live_iterator_status
1312 lttng_live_session_get_new_streams(struct lttng_live_session *session,
1313                                    bt_self_message_iterator *self_msg_iter)
1314 {
1315     struct lttng_viewer_cmd cmd;
1316     struct lttng_viewer_new_streams_request rq;
1317     struct lttng_viewer_new_streams_response rp;
1318     struct lttng_live_msg_iter *lttng_live_msg_iter = session->lttng_live_msg_iter;
1319     enum lttng_live_viewer_status viewer_status;
1320     live_viewer_connection *viewer_connection = lttng_live_msg_iter->viewer_connection.get();
1321     uint32_t streams_count;
1322     const size_t cmd_buf_len = sizeof(cmd) + sizeof(rq);
1323     char cmd_buf[cmd_buf_len];
1324
1325     if (!session->new_streams_needed) {
1326         return LTTNG_LIVE_ITERATOR_STATUS_OK;
1327     }
1328
1329     BT_CPPLOGD_SPEC(viewer_connection->logger,
1330                     "Requesting new streams for session: cmd={}, session-id={}",
1331                     LTTNG_VIEWER_GET_NEW_STREAMS, session->id);
1332
1333     cmd.cmd = htobe32(LTTNG_VIEWER_GET_NEW_STREAMS);
1334     cmd.data_size = htobe64((uint64_t) sizeof(rq));
1335     cmd.cmd_version = htobe32(0);
1336
1337     memset(&rq, 0, sizeof(rq));
1338     rq.session_id = htobe64(session->id);
1339
1340     /*
1341      * Merge the cmd and connection request to prevent a write-write
1342      * sequence on the TCP socket. Otherwise, a delayed ACK will prevent the
1343      * second write to be performed quickly in presence of Nagle's algorithm.
1344      */
1345     memcpy(cmd_buf, &cmd, sizeof(cmd));
1346     memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
1347
1348     viewer_status = lttng_live_send(viewer_connection, &cmd_buf, cmd_buf_len);
1349     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1350         viewer_handle_send_status(viewer_status, "get new streams command");
1351         return viewer_status_to_live_iterator_status(viewer_status);
1352     }
1353
1354     viewer_status = lttng_live_recv(viewer_connection, &rp, sizeof(rp));
1355     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1356         viewer_handle_recv_status(viewer_status, "get new streams reply");
1357         return viewer_status_to_live_iterator_status(viewer_status);
1358     }
1359
1360     streams_count = be32toh(rp.streams_count);
1361
1362     switch (be32toh(rp.status)) {
1363     case LTTNG_VIEWER_NEW_STREAMS_OK:
1364         session->new_streams_needed = false;
1365         break;
1366     case LTTNG_VIEWER_NEW_STREAMS_NO_NEW:
1367         session->new_streams_needed = false;
1368         return LTTNG_LIVE_ITERATOR_STATUS_OK;
1369     case LTTNG_VIEWER_NEW_STREAMS_HUP:
1370         session->new_streams_needed = false;
1371         session->closed = true;
1372         return LTTNG_LIVE_ITERATOR_STATUS_END;
1373     case LTTNG_VIEWER_NEW_STREAMS_ERR:
1374         BT_CPPLOGD_SPEC(viewer_connection->logger, "Received get_new_streams response: error");
1375         return LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1376     default:
1377         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
1378                                      "Received get_new_streams response: Unknown return code {}",
1379                                      be32toh(rp.status));
1380         return LTTNG_LIVE_ITERATOR_STATUS_ERROR;
1381     }
1382
1383     viewer_status = receive_streams(session, streams_count, self_msg_iter);
1384     if (viewer_status != LTTNG_LIVE_VIEWER_STATUS_OK) {
1385         viewer_handle_recv_status(viewer_status, "new streams");
1386         return viewer_status_to_live_iterator_status(viewer_status);
1387     }
1388
1389     return LTTNG_LIVE_ITERATOR_STATUS_OK;
1390 }
1391
1392 enum lttng_live_viewer_status
1393 live_viewer_connection_create(const char *url, bool in_query,
1394                               struct lttng_live_msg_iter *lttng_live_msg_iter,
1395                               const bt2c::Logger& parentLogger, live_viewer_connection::UP& viewer)
1396 {
1397     auto viewer_connection = bt2s::make_unique<live_viewer_connection>(parentLogger);
1398
1399     if (bt_socket_init(viewer_connection->logger) != 0) {
1400         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger, "Failed to init socket");
1401         return LTTNG_LIVE_VIEWER_STATUS_ERROR;
1402     }
1403
1404     viewer_connection->control_sock = BT_INVALID_SOCKET;
1405     viewer_connection->port = -1;
1406     viewer_connection->in_query = in_query;
1407     viewer_connection->lttng_live_msg_iter = lttng_live_msg_iter;
1408     viewer_connection->url = url;
1409
1410     BT_CPPLOGD_SPEC(viewer_connection->logger, "Establishing connection to url \"{}\"...", url);
1411     const auto status = lttng_live_connect_viewer(viewer_connection.get());
1412
1413     /*
1414      * Only print error and append cause in case of error. not in case of
1415      * interruption.
1416      */
1417     if (status == LTTNG_LIVE_VIEWER_STATUS_ERROR) {
1418         BT_CPPLOGE_APPEND_CAUSE_SPEC(viewer_connection->logger,
1419                                      "Failed to establish connection: "
1420                                      "url=\"{}\"",
1421                                      url);
1422         return status;
1423     } else if (status == LTTNG_LIVE_VIEWER_STATUS_INTERRUPTED) {
1424         return status;
1425     }
1426     BT_CPPLOGD_SPEC(viewer_connection->logger, "Connection to url \"{}\" is established", url);
1427
1428     viewer = std::move(viewer_connection);
1429     return LTTNG_LIVE_VIEWER_STATUS_OK;
1430 }
1431
1432 live_viewer_connection::~live_viewer_connection()
1433 {
1434     BT_CPPLOGD_SPEC(this->logger, "Closing connection to relay: relay-url=\"{}\"", this->url);
1435
1436     viewer_connection_close_socket(this);
1437
1438     bt_socket_fini();
1439 }