src/bin/lttng-sessiond/cmd.c

   1 /*
   2  * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <assert.h>
  20 #include <urcu/list.h>
  21 #include <urcu/uatomic.h>
  22
  23 #include <common/defaults.h>
  24 #include <common/common.h>
  25 #include <common/sessiond-comm/sessiond-comm.h>
  26 #include <common/relayd/relayd.h>
  27
  28 #include "channel.h"
  29 #include "consumer.h"
  30 #include "event.h"
  31 #include "kernel.h"
  32 #include "kernel-consumer.h"
  33 #include "lttng-sessiond.h"
  34 #include "utils.h"
  35
  36 #include "cmd.h"
  37
  38 /*
  39  * Used to keep a unique index for each relayd socket created where this value
  40  * is associated with streams on the consumer so it can match the right relayd
  41  * to send to.
  42  *
  43  * This value should be incremented atomically for safety purposes and future
  44  * possible concurrent access.
  45  */
  46 static unsigned int relayd_net_seq_idx;
  47
  48 /*
  49  * Create a session path used by list_lttng_sessions for the case that the
  50  * session consumer is on the network.
  51  */
  52 static int build_network_session_path(char *dst, size_t size,
  53                 struct ltt_session *session)
  54 {
  55         int ret, kdata_port, udata_port;
  56         struct lttng_uri *kuri = NULL, *uuri = NULL, *uri = NULL;
  57         char tmp_uurl[PATH_MAX], tmp_urls[PATH_MAX];
  58
  59         assert(session);
  60         assert(dst);
  61
  62         memset(tmp_urls, 0, sizeof(tmp_urls));
  63         memset(tmp_uurl, 0, sizeof(tmp_uurl));
  64
  65         kdata_port = udata_port = DEFAULT_NETWORK_DATA_PORT;
  66
  67         if (session->kernel_session && session->kernel_session->consumer) {
  68                 kuri = &session->kernel_session->consumer->dst.net.control;
  69                 kdata_port = session->kernel_session->consumer->dst.net.data.port;
  70         }
  71
  72         if (session->ust_session && session->ust_session->consumer) {
  73                 uuri = &session->ust_session->consumer->dst.net.control;
  74                 udata_port = session->ust_session->consumer->dst.net.data.port;
  75         }
  76
  77         if (uuri == NULL && kuri == NULL) {
  78                 uri = &session->consumer->dst.net.control;
  79                 kdata_port = session->consumer->dst.net.data.port;
  80         } else if (kuri && uuri) {
  81                 ret = uri_compare(kuri, uuri);
  82                 if (ret) {
  83                         /* Not Equal */
  84                         uri = kuri;
  85                         /* Build uuri URL string */
  86                         ret = uri_to_str_url(uuri, tmp_uurl, sizeof(tmp_uurl));
  87                         if (ret < 0) {
  88                                 goto error;
  89                         }
  90                 } else {
  91                         uri = kuri;
  92                 }
  93         } else if (kuri && uuri == NULL) {
  94                 uri = kuri;
  95         } else if (uuri && kuri == NULL) {
  96                 uri = uuri;
  97         }
  98
  99         ret = uri_to_str_url(uri, tmp_urls, sizeof(tmp_urls));
 100         if (ret < 0) {
 101                 goto error;
 102         }
 103
 104         if (strlen(tmp_uurl) > 0) {
 105                 ret = snprintf(dst, size, "[K]: %s [data: %d] -- [U]: %s [data: %d]",
 106                                 tmp_urls, kdata_port, tmp_uurl, udata_port);
 107         } else {
 108                 ret = snprintf(dst, size, "%s [data: %d]", tmp_urls, kdata_port);
 109         }
 110
 111 error:
 112         return ret;
 113 }
 114
 115 /*
 116  * Fill lttng_channel array of all channels.
 117  */
 118 static void list_lttng_channels(int domain, struct ltt_session *session,
 119                 struct lttng_channel *channels)
 120 {
 121         int i = 0;
 122         struct ltt_kernel_channel *kchan;
 123
 124         DBG("Listing channels for session %s", session->name);
 125
 126         switch (domain) {
 127         case LTTNG_DOMAIN_KERNEL:
 128                 /* Kernel channels */
 129                 if (session->kernel_session != NULL) {
 130                         cds_list_for_each_entry(kchan,
 131                                         &session->kernel_session->channel_list.head, list) {
 132                                 /* Copy lttng_channel struct to array */
 133                                 memcpy(&channels[i], kchan->channel, sizeof(struct lttng_channel));
 134                                 channels[i].enabled = kchan->enabled;
 135                                 i++;
 136                         }
 137                 }
 138                 break;
 139         case LTTNG_DOMAIN_UST:
 140         {
 141                 struct lttng_ht_iter iter;
 142                 struct ltt_ust_channel *uchan;
 143
 144                 cds_lfht_for_each_entry(session->ust_session->domain_global.channels->ht,
 145                                 &iter.iter, uchan, node.node) {
 146                         strncpy(channels[i].name, uchan->name, LTTNG_SYMBOL_NAME_LEN);
 147                         channels[i].attr.overwrite = uchan->attr.overwrite;
 148                         channels[i].attr.subbuf_size = uchan->attr.subbuf_size;
 149                         channels[i].attr.num_subbuf = uchan->attr.num_subbuf;
 150                         channels[i].attr.switch_timer_interval =
 151                                 uchan->attr.switch_timer_interval;
 152                         channels[i].attr.read_timer_interval =
 153                                 uchan->attr.read_timer_interval;
 154                         channels[i].enabled = uchan->enabled;
 155                         switch (uchan->attr.output) {
 156                         case LTTNG_UST_MMAP:
 157                         default:
 158                                 channels[i].attr.output = LTTNG_EVENT_MMAP;
 159                                 break;
 160                         }
 161                         i++;
 162                 }
 163                 break;
 164         }
 165         default:
 166                 break;
 167         }
 168 }
 169
 170 /*
 171  * Create a list of ust global domain events.
 172  */
 173 static int list_lttng_ust_global_events(char *channel_name,
 174                 struct ltt_ust_domain_global *ust_global, struct lttng_event **events)
 175 {
 176         int i = 0, ret = 0;
 177         unsigned int nb_event = 0;
 178         struct lttng_ht_iter iter;
 179         struct lttng_ht_node_str *node;
 180         struct ltt_ust_channel *uchan;
 181         struct ltt_ust_event *uevent;
 182         struct lttng_event *tmp;
 183
 184         DBG("Listing UST global events for channel %s", channel_name);
 185
 186         rcu_read_lock();
 187
 188         lttng_ht_lookup(ust_global->channels, (void *)channel_name, &iter);
 189         node = lttng_ht_iter_get_node_str(&iter);
 190         if (node == NULL) {
 191                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 192                 goto error;
 193         }
 194
 195         uchan = caa_container_of(&node->node, struct ltt_ust_channel, node.node);
 196
 197         nb_event += lttng_ht_get_count(uchan->events);
 198
 199         if (nb_event == 0) {
 200                 ret = nb_event;
 201                 goto error;
 202         }
 203
 204         DBG3("Listing UST global %d events", nb_event);
 205
 206         tmp = zmalloc(nb_event * sizeof(struct lttng_event));
 207         if (tmp == NULL) {
 208                 ret = LTTNG_ERR_FATAL;
 209                 goto error;
 210         }
 211
 212         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent, node.node) {
 213                 strncpy(tmp[i].name, uevent->attr.name, LTTNG_SYMBOL_NAME_LEN);
 214                 tmp[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 215                 tmp[i].enabled = uevent->enabled;
 216
 217                 switch (uevent->attr.instrumentation) {
 218                 case LTTNG_UST_TRACEPOINT:
 219                         tmp[i].type = LTTNG_EVENT_TRACEPOINT;
 220                         break;
 221                 case LTTNG_UST_PROBE:
 222                         tmp[i].type = LTTNG_EVENT_PROBE;
 223                         break;
 224                 case LTTNG_UST_FUNCTION:
 225                         tmp[i].type = LTTNG_EVENT_FUNCTION;
 226                         break;
 227                 }
 228
 229                 tmp[i].loglevel = uevent->attr.loglevel;
 230                 switch (uevent->attr.loglevel_type) {
 231                 case LTTNG_UST_LOGLEVEL_ALL:
 232                         tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
 233                         break;
 234                 case LTTNG_UST_LOGLEVEL_RANGE:
 235                         tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
 236                         break;
 237                 case LTTNG_UST_LOGLEVEL_SINGLE:
 238                         tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
 239                         break;
 240                 }
 241                 if (uevent->filter) {
 242                         tmp[i].filter = 1;
 243                 }
 244                 i++;
 245         }
 246
 247         ret = nb_event;
 248         *events = tmp;
 249
 250 error:
 251         rcu_read_unlock();
 252         return ret;
 253 }
 254
 255 /*
 256  * Fill lttng_event array of all kernel events in the channel.
 257  */
 258 static int list_lttng_kernel_events(char *channel_name,
 259                 struct ltt_kernel_session *kernel_session, struct lttng_event **events)
 260 {
 261         int i = 0, ret;
 262         unsigned int nb_event;
 263         struct ltt_kernel_event *event;
 264         struct ltt_kernel_channel *kchan;
 265
 266         kchan = trace_kernel_get_channel_by_name(channel_name, kernel_session);
 267         if (kchan == NULL) {
 268                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 269                 goto error;
 270         }
 271
 272         nb_event = kchan->event_count;
 273
 274         DBG("Listing events for channel %s", kchan->channel->name);
 275
 276         if (nb_event == 0) {
 277                 goto end;
 278         }
 279
 280         *events = zmalloc(nb_event * sizeof(struct lttng_event));
 281         if (*events == NULL) {
 282                 ret = LTTNG_ERR_FATAL;
 283                 goto error;
 284         }
 285
 286         /* Kernel channels */
 287         cds_list_for_each_entry(event, &kchan->events_list.head , list) {
 288                 strncpy((*events)[i].name, event->event->name, LTTNG_SYMBOL_NAME_LEN);
 289                 (*events)[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 290                 (*events)[i].enabled = event->enabled;
 291
 292                 switch (event->event->instrumentation) {
 293                 case LTTNG_KERNEL_TRACEPOINT:
 294                         (*events)[i].type = LTTNG_EVENT_TRACEPOINT;
 295                         break;
 296                 case LTTNG_KERNEL_KPROBE:
 297                 case LTTNG_KERNEL_KRETPROBE:
 298                         (*events)[i].type = LTTNG_EVENT_PROBE;
 299                         memcpy(&(*events)[i].attr.probe, &event->event->u.kprobe,
 300                                         sizeof(struct lttng_kernel_kprobe));
 301                         break;
 302                 case LTTNG_KERNEL_FUNCTION:
 303                         (*events)[i].type = LTTNG_EVENT_FUNCTION;
 304                         memcpy(&((*events)[i].attr.ftrace), &event->event->u.ftrace,
 305                                         sizeof(struct lttng_kernel_function));
 306                         break;
 307                 case LTTNG_KERNEL_NOOP:
 308                         (*events)[i].type = LTTNG_EVENT_NOOP;
 309                         break;
 310                 case LTTNG_KERNEL_SYSCALL:
 311                         (*events)[i].type = LTTNG_EVENT_SYSCALL;
 312                         break;
 313                 case LTTNG_KERNEL_ALL:
 314                         assert(0);
 315                         break;
 316                 }
 317                 i++;
 318         }
 319
 320 end:
 321         return nb_event;
 322
 323 error:
 324         /* Negate the error code to differentiate the size from an error */
 325         return -ret;
 326 }
 327
 328 /*
 329  * Add URI so the consumer output object. Set the correct path depending on the
 330  * domain adding the default trace directory.
 331  */
 332 static int add_uri_to_consumer(struct consumer_output *consumer,
 333                 struct lttng_uri *uri, int domain, const char *session_name)
 334 {
 335         int ret = LTTNG_OK;
 336         const char *default_trace_dir;
 337
 338         assert(uri);
 339
 340         if (consumer == NULL) {
 341                 DBG("No consumer detected. Don't add URI. Stopping.");
 342                 ret = LTTNG_ERR_NO_CONSUMER;
 343                 goto error;
 344         }
 345
 346         switch (domain) {
 347         case LTTNG_DOMAIN_KERNEL:
 348                 default_trace_dir = DEFAULT_KERNEL_TRACE_DIR;
 349                 break;
 350         case LTTNG_DOMAIN_UST:
 351                 default_trace_dir = DEFAULT_UST_TRACE_DIR;
 352                 break;
 353         default:
 354                 /*
 355                  * This case is possible is we try to add the URI to the global tracing
 356                  * session consumer object which in this case there is no subdir.
 357                  */
 358                 default_trace_dir = "";
 359         }
 360
 361         switch (uri->dtype) {
 362         case LTTNG_DST_IPV4:
 363         case LTTNG_DST_IPV6:
 364                 DBG2("Setting network URI to consumer");
 365
 366                 /* Set URI into consumer output object */
 367                 ret = consumer_set_network_uri(consumer, uri);
 368                 if (ret < 0) {
 369                         ret = LTTNG_ERR_FATAL;
 370                         goto error;
 371                 } else if (ret == 1) {
 372                         /*
 373                          * URI was the same in the consumer so we do not append the subdir
 374                          * again so to not duplicate output dir.
 375                          */
 376                         goto error;
 377                 }
 378
 379                 if (uri->stype == LTTNG_STREAM_CONTROL && strlen(uri->subdir) == 0) {
 380                         ret = consumer_set_subdir(consumer, session_name);
 381                         if (ret < 0) {
 382                                 ret = LTTNG_ERR_FATAL;
 383                                 goto error;
 384                         }
 385                 }
 386
 387                 if (uri->stype == LTTNG_STREAM_CONTROL) {
 388                         /* On a new subdir, reappend the default trace dir. */
 389                         strncat(consumer->subdir, default_trace_dir,
 390                                         sizeof(consumer->subdir) - strlen(consumer->subdir) - 1);
 391                         DBG3("Append domain trace name to subdir %s", consumer->subdir);
 392                 }
 393
 394                 break;
 395         case LTTNG_DST_PATH:
 396                 DBG2("Setting trace directory path from URI to %s", uri->dst.path);
 397                 memset(consumer->dst.trace_path, 0,
 398                                 sizeof(consumer->dst.trace_path));
 399                 strncpy(consumer->dst.trace_path, uri->dst.path,
 400                                 sizeof(consumer->dst.trace_path));
 401                 /* Append default trace dir */
 402                 strncat(consumer->dst.trace_path, default_trace_dir,
 403                                 sizeof(consumer->dst.trace_path) -
 404                                 strlen(consumer->dst.trace_path) - 1);
 405                 /* Flag consumer as local. */
 406                 consumer->type = CONSUMER_DST_LOCAL;
 407                 break;
 408         }
 409
 410 error:
 411         return ret;
 412 }
 413
 414 /*
 415  * Init tracing by creating trace directory and sending fds kernel consumer.
 416  */
 417 static int init_kernel_tracing(struct ltt_kernel_session *session)
 418 {
 419         int ret = 0;
 420         struct lttng_ht_iter iter;
 421         struct consumer_socket *socket;
 422
 423         assert(session);
 424
 425         if (session->consumer_fds_sent == 0 && session->consumer != NULL) {
 426                 cds_lfht_for_each_entry(session->consumer->socks->ht, &iter.iter,
 427                                 socket, node.node) {
 428                         /* Code flow error */
 429                         assert(socket->fd >= 0);
 430
 431                         pthread_mutex_lock(socket->lock);
 432                         ret = kernel_consumer_send_session(socket->fd, session);
 433                         pthread_mutex_unlock(socket->lock);
 434                         if (ret < 0) {
 435                                 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
 436                                 goto error;
 437                         }
 438                 }
 439         }
 440
 441 error:
 442         return ret;
 443 }
 444
 445 /*
 446  * Create a socket to the relayd using the URI.
 447  *
 448  * On success, the relayd_sock pointer is set to the created socket.
 449  * Else, it's stays untouched and a lttcomm error code is returned.
 450  */
 451 static int create_connect_relayd(struct consumer_output *output,
 452                 const char *session_name, struct lttng_uri *uri,
 453                 struct lttcomm_sock **relayd_sock)
 454 {
 455         int ret;
 456         struct lttcomm_sock *sock;
 457
 458         /* Create socket object from URI */
 459         sock = lttcomm_alloc_sock_from_uri(uri);
 460         if (sock == NULL) {
 461                 ret = LTTNG_ERR_FATAL;
 462                 goto error;
 463         }
 464
 465         ret = lttcomm_create_sock(sock);
 466         if (ret < 0) {
 467                 ret = LTTNG_ERR_FATAL;
 468                 goto error;
 469         }
 470
 471         /* Connect to relayd so we can proceed with a session creation. */
 472         ret = relayd_connect(sock);
 473         if (ret < 0) {
 474                 ERR("Unable to reach lttng-relayd");
 475                 ret = LTTNG_ERR_RELAYD_CONNECT_FAIL;
 476                 goto free_sock;
 477         }
 478
 479         /* Create socket for control stream. */
 480         if (uri->stype == LTTNG_STREAM_CONTROL) {
 481                 DBG3("Creating relayd stream socket from URI");
 482
 483                 /* Check relayd version */
 484                 ret = relayd_version_check(sock, RELAYD_VERSION_COMM_MAJOR,
 485                                 RELAYD_VERSION_COMM_MINOR);
 486                 if (ret < 0) {
 487                         ret = LTTNG_ERR_RELAYD_VERSION_FAIL;
 488                         goto close_sock;
 489                 }
 490         } else if (uri->stype == LTTNG_STREAM_DATA) {
 491                 DBG3("Creating relayd data socket from URI");
 492         } else {
 493                 /* Command is not valid */
 494                 ERR("Relayd invalid stream type: %d", uri->stype);
 495                 ret = LTTNG_ERR_INVALID;
 496                 goto close_sock;
 497         }
 498
 499         *relayd_sock = sock;
 500
 501         return LTTNG_OK;
 502
 503 close_sock:
 504         if (sock) {
 505                 (void) relayd_close(sock);
 506         }
 507 free_sock:
 508         if (sock) {
 509                 lttcomm_destroy_sock(sock);
 510         }
 511 error:
 512         return ret;
 513 }
 514
 515 /*
 516  * Connect to the relayd using URI and send the socket to the right consumer.
 517  */
 518 static int send_consumer_relayd_socket(int domain, struct ltt_session *session,
 519                 struct lttng_uri *relayd_uri, struct consumer_output *consumer,
 520                 int consumer_fd)
 521 {
 522         int ret;
 523         struct lttcomm_sock *sock = NULL;
 524
 525         /* Set the network sequence index if not set. */
 526         if (consumer->net_seq_index == -1) {
 527                 /*
 528                  * Increment net_seq_idx because we are about to transfer the
 529                  * new relayd socket to the consumer.
 530                  */
 531                 uatomic_inc(&relayd_net_seq_idx);
 532                 /* Assign unique key so the consumer can match streams */
 533                 uatomic_set(&consumer->net_seq_index,
 534                                 uatomic_read(&relayd_net_seq_idx));
 535         }
 536
 537         /* Connect to relayd and make version check if uri is the control. */
 538         ret = create_connect_relayd(consumer, session->name, relayd_uri, &sock);
 539         if (ret != LTTNG_OK) {
 540                 goto close_sock;
 541         }
 542
 543         /* If the control socket is connected, network session is ready */
 544         if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
 545                 session->net_handle = 1;
 546         }
 547
 548         /* Send relayd socket to consumer. */
 549         ret = consumer_send_relayd_socket(consumer_fd, sock,
 550                         consumer, relayd_uri->stype);
 551         if (ret < 0) {
 552                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
 553                 goto close_sock;
 554         }
 555
 556         /* Flag that the corresponding socket was sent. */
 557         if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
 558                 consumer->dst.net.control_sock_sent = 1;
 559         } else if (relayd_uri->stype == LTTNG_STREAM_DATA) {
 560                 consumer->dst.net.data_sock_sent = 1;
 561         }
 562
 563         ret = LTTNG_OK;
 564
 565         /*
 566          * Close socket which was dup on the consumer side. The session daemon does
 567          * NOT keep track of the relayd socket(s) once transfer to the consumer.
 568          */
 569
 570 close_sock:
 571         if (sock) {
 572                 (void) relayd_close(sock);
 573                 lttcomm_destroy_sock(sock);
 574         }
 575
 576         return ret;
 577 }
 578
 579 /*
 580  * Send both relayd sockets to a specific consumer and domain.  This is a
 581  * helper function to facilitate sending the information to the consumer for a
 582  * session.
 583  */
 584 static int send_consumer_relayd_sockets(int domain,
 585                 struct ltt_session *session, struct consumer_output *consumer, int fd)
 586 {
 587         int ret = LTTNG_OK;
 588
 589         assert(session);
 590         assert(consumer);
 591
 592         /* Sending control relayd socket. */
 593         if (!consumer->dst.net.control_sock_sent) {
 594                 ret = send_consumer_relayd_socket(domain, session,
 595                                 &consumer->dst.net.control, consumer, fd);
 596                 if (ret != LTTNG_OK) {
 597                         goto error;
 598                 }
 599         }
 600
 601         /* Sending data relayd socket. */
 602         if (!consumer->dst.net.data_sock_sent) {
 603                 ret = send_consumer_relayd_socket(domain, session,
 604                                 &consumer->dst.net.data, consumer, fd);
 605                 if (ret != LTTNG_OK) {
 606                         goto error;
 607                 }
 608         }
 609
 610 error:
 611         return ret;
 612 }
 613
 614 /*
 615  * Setup relayd connections for a tracing session. First creates the socket to
 616  * the relayd and send them to the right domain consumer. Consumer type MUST be
 617  * network.
 618  */
 619 static int setup_relayd(struct ltt_session *session)
 620 {
 621         int ret = LTTNG_OK;
 622         struct ltt_ust_session *usess;
 623         struct ltt_kernel_session *ksess;
 624         struct consumer_socket *socket;
 625         struct lttng_ht_iter iter;
 626
 627         assert(session);
 628
 629         usess = session->ust_session;
 630         ksess = session->kernel_session;
 631
 632         DBG2("Setting relayd for session %s", session->name);
 633
 634         if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
 635                         && usess->consumer->enabled) {
 636                 /* For each consumer socket, send relayd sockets */
 637                 cds_lfht_for_each_entry(usess->consumer->socks->ht, &iter.iter,
 638                                 socket, node.node) {
 639                         /* Code flow error */
 640                         assert(socket->fd >= 0);
 641
 642                         pthread_mutex_lock(socket->lock);
 643                         ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session,
 644                                         usess->consumer, socket->fd);
 645                         pthread_mutex_unlock(socket->lock);
 646                         if (ret != LTTNG_OK) {
 647                                 goto error;
 648                         }
 649                 }
 650         }
 651
 652         if (ksess && ksess->consumer && ksess->consumer->type == CONSUMER_DST_NET
 653                         && ksess->consumer->enabled) {
 654                 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
 655                                 socket, node.node) {
 656                         /* Code flow error */
 657                         assert(socket->fd >= 0);
 658
 659                         pthread_mutex_lock(socket->lock);
 660                         ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session,
 661                                         ksess->consumer, socket->fd);
 662                         pthread_mutex_unlock(socket->lock);
 663                         if (ret != LTTNG_OK) {
 664                                 goto error;
 665                         }
 666                 }
 667         }
 668
 669 error:
 670         return ret;
 671 }
 672
 673 /*
 674  * Start a kernel session by opening all necessary streams.
 675  */
 676 static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
 677 {
 678         int ret;
 679         struct ltt_kernel_channel *kchan;
 680
 681         /* Open kernel metadata */
 682         if (ksess->metadata == NULL) {
 683                 ret = kernel_open_metadata(ksess);
 684                 if (ret < 0) {
 685                         ret = LTTNG_ERR_KERN_META_FAIL;
 686                         goto error;
 687                 }
 688         }
 689
 690         /* Open kernel metadata stream */
 691         if (ksess->metadata_stream_fd < 0) {
 692                 ret = kernel_open_metadata_stream(ksess);
 693                 if (ret < 0) {
 694                         ERR("Kernel create metadata stream failed");
 695                         ret = LTTNG_ERR_KERN_STREAM_FAIL;
 696                         goto error;
 697                 }
 698         }
 699
 700         /* For each channel */
 701         cds_list_for_each_entry(kchan, &ksess->channel_list.head, list) {
 702                 if (kchan->stream_count == 0) {
 703                         ret = kernel_open_channel_stream(kchan);
 704                         if (ret < 0) {
 705                                 ret = LTTNG_ERR_KERN_STREAM_FAIL;
 706                                 goto error;
 707                         }
 708                         /* Update the stream global counter */
 709                         ksess->stream_count_global += ret;
 710                 }
 711         }
 712
 713         /* Setup kernel consumer socket and send fds to it */
 714         ret = init_kernel_tracing(ksess);
 715         if (ret < 0) {
 716                 ret = LTTNG_ERR_KERN_START_FAIL;
 717                 goto error;
 718         }
 719
 720         /* This start the kernel tracing */
 721         ret = kernel_start_session(ksess);
 722         if (ret < 0) {
 723                 ret = LTTNG_ERR_KERN_START_FAIL;
 724                 goto error;
 725         }
 726
 727         /* Quiescent wait after starting trace */
 728         kernel_wait_quiescent(wpipe);
 729
 730         ksess->started = 1;
 731
 732         ret = LTTNG_OK;
 733
 734 error:
 735         return ret;
 736 }
 737
 738 /*
 739  * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
 740  */
 741 int cmd_disable_channel(struct ltt_session *session, int domain,
 742                 char *channel_name)
 743 {
 744         int ret;
 745         struct ltt_ust_session *usess;
 746
 747         usess = session->ust_session;
 748
 749         switch (domain) {
 750         case LTTNG_DOMAIN_KERNEL:
 751         {
 752                 ret = channel_kernel_disable(session->kernel_session,
 753                                 channel_name);
 754                 if (ret != LTTNG_OK) {
 755                         goto error;
 756                 }
 757
 758                 kernel_wait_quiescent(kernel_tracer_fd);
 759                 break;
 760         }
 761         case LTTNG_DOMAIN_UST:
 762         {
 763                 struct ltt_ust_channel *uchan;
 764                 struct lttng_ht *chan_ht;
 765
 766                 chan_ht = usess->domain_global.channels;
 767
 768                 uchan = trace_ust_find_channel_by_name(chan_ht, channel_name);
 769                 if (uchan == NULL) {
 770                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 771                         goto error;
 772                 }
 773
 774                 ret = channel_ust_disable(usess, domain, uchan);
 775                 if (ret != LTTNG_OK) {
 776                         goto error;
 777                 }
 778                 break;
 779         }
 780 #if 0
 781         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 782         case LTTNG_DOMAIN_UST_EXEC_NAME:
 783         case LTTNG_DOMAIN_UST_PID:
 784 #endif
 785         default:
 786                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
 787                 goto error;
 788         }
 789
 790         ret = LTTNG_OK;
 791
 792 error:
 793         return ret;
 794 }
 795
 796 /*
 797  * Command LTTNG_ENABLE_CHANNEL processed by the client thread.
 798  *
 799  * The wpipe arguments is used as a notifier for the kernel thread.
 800  */
 801 int cmd_enable_channel(struct ltt_session *session,
 802                 int domain, struct lttng_channel *attr, int wpipe)
 803 {
 804         int ret;
 805         struct ltt_ust_session *usess = session->ust_session;
 806         struct lttng_ht *chan_ht;
 807
 808         assert(session);
 809         assert(attr);
 810
 811         DBG("Enabling channel %s for session %s", attr->name, session->name);
 812
 813         switch (domain) {
 814         case LTTNG_DOMAIN_KERNEL:
 815         {
 816                 struct ltt_kernel_channel *kchan;
 817
 818                 /* Mandatory for a kernel channel. */
 819                 assert(wpipe > 0);
 820
 821                 kchan = trace_kernel_get_channel_by_name(attr->name,
 822                                 session->kernel_session);
 823                 if (kchan == NULL) {
 824                         ret = channel_kernel_create(session->kernel_session, attr, wpipe);
 825                 } else {
 826                         ret = channel_kernel_enable(session->kernel_session, kchan);
 827                 }
 828
 829                 if (ret != LTTNG_OK) {
 830                         goto error;
 831                 }
 832
 833                 kernel_wait_quiescent(wpipe);
 834
 835                 /*
 836                  * If the session was previously started, start as well this newly
 837                  * created kernel session so the events/channels enabled *after* the
 838                  * start actually work.
 839                  */
 840                 if (session->started && !session->kernel_session->started) {
 841                         ret = start_kernel_session(session->kernel_session, wpipe);
 842                         if (ret != LTTNG_OK) {
 843                                 goto error;
 844                         }
 845                 }
 846                 break;
 847         }
 848         case LTTNG_DOMAIN_UST:
 849         {
 850                 struct ltt_ust_channel *uchan;
 851
 852                 chan_ht = usess->domain_global.channels;
 853
 854                 uchan = trace_ust_find_channel_by_name(chan_ht, attr->name);
 855                 if (uchan == NULL) {
 856                         ret = channel_ust_create(usess, domain, attr);
 857                 } else {
 858                         ret = channel_ust_enable(usess, domain, uchan);
 859                 }
 860
 861                 /* Start the UST session if the session was already started. */
 862                 if (session->started && !usess->start_trace) {
 863                         ret = ust_app_start_trace_all(usess);
 864                         if (ret < 0) {
 865                                 ret = LTTNG_ERR_UST_START_FAIL;
 866                                 goto error;
 867                         }
 868                         ret = LTTNG_OK;
 869                         usess->start_trace = 1;
 870                 }
 871                 break;
 872         }
 873 #if 0
 874         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 875         case LTTNG_DOMAIN_UST_EXEC_NAME:
 876         case LTTNG_DOMAIN_UST_PID:
 877 #endif
 878         default:
 879                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
 880                 goto error;
 881         }
 882
 883 error:
 884         return ret;
 885 }
 886
 887
 888 /*
 889  * Command LTTNG_DISABLE_EVENT processed by the client thread.
 890  */
 891 int cmd_disable_event(struct ltt_session *session, int domain,
 892                 char *channel_name, char *event_name)
 893 {
 894         int ret;
 895
 896         switch (domain) {
 897         case LTTNG_DOMAIN_KERNEL:
 898         {
 899                 struct ltt_kernel_channel *kchan;
 900                 struct ltt_kernel_session *ksess;
 901
 902                 ksess = session->kernel_session;
 903
 904                 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
 905                 if (kchan == NULL) {
 906                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 907                         goto error;
 908                 }
 909
 910                 ret = event_kernel_disable_tracepoint(ksess, kchan, event_name);
 911                 if (ret != LTTNG_OK) {
 912                         goto error;
 913                 }
 914
 915                 kernel_wait_quiescent(kernel_tracer_fd);
 916                 break;
 917         }
 918         case LTTNG_DOMAIN_UST:
 919         {
 920                 struct ltt_ust_channel *uchan;
 921                 struct ltt_ust_session *usess;
 922
 923                 usess = session->ust_session;
 924
 925                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 926                                 channel_name);
 927                 if (uchan == NULL) {
 928                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 929                         goto error;
 930                 }
 931
 932                 ret = event_ust_disable_tracepoint(usess, domain, uchan, event_name);
 933                 if (ret != LTTNG_OK) {
 934                         goto error;
 935                 }
 936
 937                 DBG3("Disable UST event %s in channel %s completed", event_name,
 938                                 channel_name);
 939                 break;
 940         }
 941 #if 0
 942         case LTTNG_DOMAIN_UST_EXEC_NAME:
 943         case LTTNG_DOMAIN_UST_PID:
 944         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 945 #endif
 946         default:
 947                 ret = LTTNG_ERR_UND;
 948                 goto error;
 949         }
 950
 951         ret = LTTNG_OK;
 952
 953 error:
 954         return ret;
 955 }
 956
 957 /*
 958  * Command LTTNG_DISABLE_ALL_EVENT processed by the client thread.
 959  */
 960 int cmd_disable_event_all(struct ltt_session *session, int domain,
 961                 char *channel_name)
 962 {
 963         int ret;
 964
 965         switch (domain) {
 966         case LTTNG_DOMAIN_KERNEL:
 967         {
 968                 struct ltt_kernel_session *ksess;
 969                 struct ltt_kernel_channel *kchan;
 970
 971                 ksess = session->kernel_session;
 972
 973                 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
 974                 if (kchan == NULL) {
 975                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 976                         goto error;
 977                 }
 978
 979                 ret = event_kernel_disable_all(ksess, kchan);
 980                 if (ret != LTTNG_OK) {
 981                         goto error;
 982                 }
 983
 984                 kernel_wait_quiescent(kernel_tracer_fd);
 985                 break;
 986         }
 987         case LTTNG_DOMAIN_UST:
 988         {
 989                 struct ltt_ust_session *usess;
 990                 struct ltt_ust_channel *uchan;
 991
 992                 usess = session->ust_session;
 993
 994                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 995                                 channel_name);
 996                 if (uchan == NULL) {
 997                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 998                         goto error;
 999                 }
1000
1001                 ret = event_ust_disable_all_tracepoints(usess, domain, uchan);
1002                 if (ret != 0) {
1003                         goto error;
1004                 }
1005
1006                 DBG3("Disable all UST events in channel %s completed", channel_name);
1007
1008                 break;
1009         }
1010 #if 0
1011         case LTTNG_DOMAIN_UST_EXEC_NAME:
1012         case LTTNG_DOMAIN_UST_PID:
1013         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1014 #endif
1015         default:
1016                 ret = LTTNG_ERR_UND;
1017                 goto error;
1018         }
1019
1020         ret = LTTNG_OK;
1021
1022 error:
1023         return ret;
1024 }
1025
1026 /*
1027  * Command LTTNG_ADD_CONTEXT processed by the client thread.
1028  */
1029 int cmd_add_context(struct ltt_session *session, int domain,
1030                 char *channel_name, char *event_name, struct lttng_event_context *ctx,
1031                 int kwpipe)
1032 {
1033         int ret;
1034
1035         switch (domain) {
1036         case LTTNG_DOMAIN_KERNEL:
1037                 assert(session->kernel_session);
1038
1039                 if (session->kernel_session->channel_count == 0) {
1040                         /* Create default channel */
1041                         ret = channel_kernel_create(session->kernel_session, NULL, kwpipe);
1042                         if (ret != LTTNG_OK) {
1043                                 goto error;
1044                         }
1045                 }
1046
1047                 /* Add kernel context to kernel tracer */
1048                 ret = context_kernel_add(session->kernel_session, ctx,
1049                                 event_name, channel_name);
1050                 if (ret != LTTNG_OK) {
1051                         goto error;
1052                 }
1053                 break;
1054         case LTTNG_DOMAIN_UST:
1055         {
1056                 struct ltt_ust_session *usess = session->ust_session;
1057                 assert(usess);
1058
1059                 unsigned int chan_count =
1060                         lttng_ht_get_count(usess->domain_global.channels);
1061                 if (chan_count == 0) {
1062                         struct lttng_channel *attr;
1063                         /* Create default channel */
1064                         attr = channel_new_default_attr(domain);
1065                         if (attr == NULL) {
1066                                 ret = LTTNG_ERR_FATAL;
1067                                 goto error;
1068                         }
1069
1070                         ret = channel_ust_create(usess, domain, attr);
1071                         if (ret != LTTNG_OK) {
1072                                 free(attr);
1073                                 goto error;
1074                         }
1075                         free(attr);
1076                 }
1077
1078
1079                 ret = context_ust_add(usess, domain, ctx, event_name, channel_name);
1080                 if (ret != LTTNG_OK) {
1081                         goto error;
1082                 }
1083                 break;
1084         }
1085 #if 0
1086         case LTTNG_DOMAIN_UST_EXEC_NAME:
1087         case LTTNG_DOMAIN_UST_PID:
1088         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1089 #endif
1090         default:
1091                 ret = LTTNG_ERR_UND;
1092                 goto error;
1093         }
1094
1095         ret = LTTNG_OK;
1096
1097 error:
1098         return ret;
1099 }
1100
1101 /*
1102  * Command LTTNG_SET_FILTER processed by the client thread.
1103  */
1104 int cmd_set_filter(struct ltt_session *session, int domain,
1105                 char *channel_name, char *event_name,
1106                 struct lttng_filter_bytecode *bytecode)
1107 {
1108         int ret;
1109
1110         switch (domain) {
1111         case LTTNG_DOMAIN_KERNEL:
1112                 ret = LTTNG_ERR_FATAL;
1113                 break;
1114         case LTTNG_DOMAIN_UST:
1115         {
1116                 struct ltt_ust_session *usess = session->ust_session;
1117
1118                 ret = filter_ust_set(usess, domain, bytecode, event_name, channel_name);
1119                 if (ret != LTTNG_OK) {
1120                         goto error;
1121                 }
1122                 break;
1123         }
1124 #if 0
1125         case LTTNG_DOMAIN_UST_EXEC_NAME:
1126         case LTTNG_DOMAIN_UST_PID:
1127         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1128 #endif
1129         default:
1130                 ret = LTTNG_ERR_UND;
1131                 goto error;
1132         }
1133
1134         ret = LTTNG_OK;
1135
1136 error:
1137         return ret;
1138
1139 }
1140
1141
1142 /*
1143  * Command LTTNG_ENABLE_EVENT processed by the client thread.
1144  */
1145 int cmd_enable_event(struct ltt_session *session, int domain,
1146                 char *channel_name, struct lttng_event *event, int wpipe)
1147 {
1148         int ret;
1149         struct lttng_channel *attr;
1150
1151         assert(session);
1152         assert(event);
1153         assert(channel_name);
1154
1155         switch (domain) {
1156         case LTTNG_DOMAIN_KERNEL:
1157         {
1158                 struct ltt_kernel_channel *kchan;
1159
1160                 kchan = trace_kernel_get_channel_by_name(channel_name,
1161                                 session->kernel_session);
1162                 if (kchan == NULL) {
1163                         attr = channel_new_default_attr(domain);
1164                         if (attr == NULL) {
1165                                 ret = LTTNG_ERR_FATAL;
1166                                 goto error;
1167                         }
1168                         strncpy(attr->name, channel_name, sizeof(attr->name));
1169
1170                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1171                         if (ret != LTTNG_OK) {
1172                                 free(attr);
1173                                 goto error;
1174                         }
1175                         free(attr);
1176                 }
1177
1178                 /* Get the newly created kernel channel pointer */
1179                 kchan = trace_kernel_get_channel_by_name(channel_name,
1180                                 session->kernel_session);
1181                 if (kchan == NULL) {
1182                         /* This sould not happen... */
1183                         ret = LTTNG_ERR_FATAL;
1184                         goto error;
1185                 }
1186
1187                 ret = event_kernel_enable_tracepoint(session->kernel_session, kchan,
1188                                 event);
1189                 if (ret != LTTNG_OK) {
1190                         goto error;
1191                 }
1192
1193                 kernel_wait_quiescent(kernel_tracer_fd);
1194                 break;
1195         }
1196         case LTTNG_DOMAIN_UST:
1197         {
1198                 struct ltt_ust_channel *uchan;
1199                 struct ltt_ust_session *usess = session->ust_session;
1200
1201                 assert(usess);
1202
1203                 /* Get channel from global UST domain */
1204                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1205                                 channel_name);
1206                 if (uchan == NULL) {
1207                         /* Create default channel */
1208                         attr = channel_new_default_attr(domain);
1209                         if (attr == NULL) {
1210                                 ret = LTTNG_ERR_FATAL;
1211                                 goto error;
1212                         }
1213                         strncpy(attr->name, channel_name, sizeof(attr->name));
1214
1215                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1216                         if (ret != LTTNG_OK) {
1217                                 free(attr);
1218                                 goto error;
1219                         }
1220                         free(attr);
1221
1222                         /* Get the newly created channel reference back */
1223                         uchan = trace_ust_find_channel_by_name(
1224                                         usess->domain_global.channels, channel_name);
1225                         assert(uchan);
1226                 }
1227
1228                 /* At this point, the session and channel exist on the tracer */
1229                 ret = event_ust_enable_tracepoint(usess, domain, uchan, event);
1230                 if (ret != LTTNG_OK) {
1231                         goto error;
1232                 }
1233                 break;
1234         }
1235 #if 0
1236         case LTTNG_DOMAIN_UST_EXEC_NAME:
1237         case LTTNG_DOMAIN_UST_PID:
1238         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1239 #endif
1240         default:
1241                 ret = LTTNG_ERR_UND;
1242                 goto error;
1243         }
1244
1245         ret = LTTNG_OK;
1246
1247 error:
1248         return ret;
1249 }
1250
1251 /*
1252  * Command LTTNG_ENABLE_ALL_EVENT processed by the client thread.
1253  */
1254 int cmd_enable_event_all(struct ltt_session *session, int domain,
1255                 char *channel_name, int event_type, int wpipe)
1256 {
1257         int ret;
1258         struct lttng_channel *attr;
1259
1260         assert(session);
1261         assert(channel_name);
1262
1263         switch (domain) {
1264         case LTTNG_DOMAIN_KERNEL:
1265         {
1266                 struct ltt_kernel_channel *kchan;
1267
1268                 assert(session->kernel_session);
1269
1270                 kchan = trace_kernel_get_channel_by_name(channel_name,
1271                                 session->kernel_session);
1272                 if (kchan == NULL) {
1273                         /* Create default channel */
1274                         attr = channel_new_default_attr(domain);
1275                         if (attr == NULL) {
1276                                 ret = LTTNG_ERR_FATAL;
1277                                 goto error;
1278                         }
1279                         strncpy(attr->name, channel_name, sizeof(attr->name));
1280
1281                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1282                         if (ret != LTTNG_OK) {
1283                                 free(attr);
1284                                 goto error;
1285                         }
1286                         free(attr);
1287
1288                         /* Get the newly created kernel channel pointer */
1289                         kchan = trace_kernel_get_channel_by_name(channel_name,
1290                                         session->kernel_session);
1291                         assert(kchan);
1292                 }
1293
1294                 switch (event_type) {
1295                 case LTTNG_EVENT_SYSCALL:
1296                         ret = event_kernel_enable_all_syscalls(session->kernel_session,
1297                                         kchan, kernel_tracer_fd);
1298                         break;
1299                 case LTTNG_EVENT_TRACEPOINT:
1300                         /*
1301                          * This call enables all LTTNG_KERNEL_TRACEPOINTS and
1302                          * events already registered to the channel.
1303                          */
1304                         ret = event_kernel_enable_all_tracepoints(session->kernel_session,
1305                                         kchan, kernel_tracer_fd);
1306                         break;
1307                 case LTTNG_EVENT_ALL:
1308                         /* Enable syscalls and tracepoints */
1309                         ret = event_kernel_enable_all(session->kernel_session,
1310                                         kchan, kernel_tracer_fd);
1311                         break;
1312                 default:
1313                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1314                         goto error;
1315                 }
1316
1317                 /* Manage return value */
1318                 if (ret != LTTNG_OK) {
1319                         goto error;
1320                 }
1321
1322                 kernel_wait_quiescent(kernel_tracer_fd);
1323                 break;
1324         }
1325         case LTTNG_DOMAIN_UST:
1326         {
1327                 struct ltt_ust_channel *uchan;
1328                 struct ltt_ust_session *usess = session->ust_session;
1329
1330                 assert(usess);
1331
1332                 /* Get channel from global UST domain */
1333                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1334                                 channel_name);
1335                 if (uchan == NULL) {
1336                         /* Create default channel */
1337                         attr = channel_new_default_attr(domain);
1338                         if (attr == NULL) {
1339                                 ret = LTTNG_ERR_FATAL;
1340                                 goto error;
1341                         }
1342                         strncpy(attr->name, channel_name, sizeof(attr->name));
1343
1344                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1345                         if (ret != LTTNG_OK) {
1346                                 free(attr);
1347                                 goto error;
1348                         }
1349                         free(attr);
1350
1351                         /* Get the newly created channel reference back */
1352                         uchan = trace_ust_find_channel_by_name(
1353                                         usess->domain_global.channels, channel_name);
1354                         assert(uchan);
1355                 }
1356
1357                 /* At this point, the session and channel exist on the tracer */
1358
1359                 switch (event_type) {
1360                 case LTTNG_EVENT_ALL:
1361                 case LTTNG_EVENT_TRACEPOINT:
1362                         ret = event_ust_enable_all_tracepoints(usess, domain, uchan);
1363                         if (ret != LTTNG_OK) {
1364                                 goto error;
1365                         }
1366                         break;
1367                 default:
1368                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
1369                         goto error;
1370                 }
1371
1372                 /* Manage return value */
1373                 if (ret != LTTNG_OK) {
1374                         goto error;
1375                 }
1376
1377                 break;
1378         }
1379 #if 0
1380         case LTTNG_DOMAIN_UST_EXEC_NAME:
1381         case LTTNG_DOMAIN_UST_PID:
1382         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1383 #endif
1384         default:
1385                 ret = LTTNG_ERR_UND;
1386                 goto error;
1387         }
1388
1389         ret = LTTNG_OK;
1390
1391 error:
1392         return ret;
1393 }
1394
1395
1396 /*
1397  * Command LTTNG_LIST_TRACEPOINTS processed by the client thread.
1398  */
1399 ssize_t cmd_list_tracepoints(int domain, struct lttng_event **events)
1400 {
1401         int ret;
1402         ssize_t nb_events = 0;
1403
1404         switch (domain) {
1405         case LTTNG_DOMAIN_KERNEL:
1406                 nb_events = kernel_list_events(kernel_tracer_fd, events);
1407                 if (nb_events < 0) {
1408                         ret = LTTNG_ERR_KERN_LIST_FAIL;
1409                         goto error;
1410                 }
1411                 break;
1412         case LTTNG_DOMAIN_UST:
1413                 nb_events = ust_app_list_events(events);
1414                 if (nb_events < 0) {
1415                         ret = LTTNG_ERR_UST_LIST_FAIL;
1416                         goto error;
1417                 }
1418                 break;
1419         default:
1420                 ret = LTTNG_ERR_UND;
1421                 goto error;
1422         }
1423
1424         return nb_events;
1425
1426 error:
1427         /* Return negative value to differentiate return code */
1428         return -ret;
1429 }
1430
1431 /*
1432  * Command LTTNG_LIST_TRACEPOINT_FIELDS processed by the client thread.
1433  */
1434 ssize_t cmd_list_tracepoint_fields(int domain,
1435                 struct lttng_event_field **fields)
1436 {
1437         int ret;
1438         ssize_t nb_fields = 0;
1439
1440         switch (domain) {
1441         case LTTNG_DOMAIN_UST:
1442                 nb_fields = ust_app_list_event_fields(fields);
1443                 if (nb_fields < 0) {
1444                         ret = LTTNG_ERR_UST_LIST_FAIL;
1445                         goto error;
1446                 }
1447                 break;
1448         case LTTNG_DOMAIN_KERNEL:
1449         default:        /* fall-through */
1450                 ret = LTTNG_ERR_UND;
1451                 goto error;
1452         }
1453
1454         return nb_fields;
1455
1456 error:
1457         /* Return negative value to differentiate return code */
1458         return -ret;
1459 }
1460
1461 /*
1462  * Command LTTNG_START_TRACE processed by the client thread.
1463  */
1464 int cmd_start_trace(struct ltt_session *session)
1465 {
1466         int ret;
1467         struct ltt_kernel_session *ksession;
1468         struct ltt_ust_session *usess;
1469
1470         assert(session);
1471
1472         /* Ease our life a bit ;) */
1473         ksession = session->kernel_session;
1474         usess = session->ust_session;
1475
1476         if (session->enabled) {
1477                 /* Already started. */
1478                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
1479                 goto error;
1480         }
1481
1482         session->enabled = 1;
1483
1484         ret = setup_relayd(session);
1485         if (ret != LTTNG_OK) {
1486                 ERR("Error setting up relayd for session %s", session->name);
1487                 goto error;
1488         }
1489
1490         /* Kernel tracing */
1491         if (ksession != NULL) {
1492                 ret = start_kernel_session(ksession, kernel_tracer_fd);
1493                 if (ret != LTTNG_OK) {
1494                         goto error;
1495                 }
1496         }
1497
1498         /* Flag session that trace should start automatically */
1499         if (usess) {
1500                 usess->start_trace = 1;
1501
1502                 ret = ust_app_start_trace_all(usess);
1503                 if (ret < 0) {
1504                         ret = LTTNG_ERR_UST_START_FAIL;
1505                         goto error;
1506                 }
1507         }
1508
1509         session->started = 1;
1510
1511         ret = LTTNG_OK;
1512
1513 error:
1514         return ret;
1515 }
1516
1517 /*
1518  * Command LTTNG_STOP_TRACE processed by the client thread.
1519  */
1520 int cmd_stop_trace(struct ltt_session *session)
1521 {
1522         int ret;
1523         struct ltt_kernel_channel *kchan;
1524         struct ltt_kernel_session *ksession;
1525         struct ltt_ust_session *usess;
1526
1527         assert(session);
1528
1529         /* Short cut */
1530         ksession = session->kernel_session;
1531         usess = session->ust_session;
1532
1533         if (!session->enabled) {
1534                 ret = LTTNG_ERR_TRACE_ALREADY_STOPPED;
1535                 goto error;
1536         }
1537
1538         session->enabled = 0;
1539
1540         /* Kernel tracer */
1541         if (ksession) {
1542                 DBG("Stop kernel tracing");
1543
1544                 /* Flush metadata if exist */
1545                 if (ksession->metadata_stream_fd >= 0) {
1546                         ret = kernel_metadata_flush_buffer(ksession->metadata_stream_fd);
1547                         if (ret < 0) {
1548                                 ERR("Kernel metadata flush failed");
1549                         }
1550                 }
1551
1552                 /* Flush all buffers before stopping */
1553                 cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
1554                         ret = kernel_flush_buffer(kchan);
1555                         if (ret < 0) {
1556                                 ERR("Kernel flush buffer error");
1557                         }
1558                 }
1559
1560                 ret = kernel_stop_session(ksession);
1561                 if (ret < 0) {
1562                         ret = LTTNG_ERR_KERN_STOP_FAIL;
1563                         goto error;
1564                 }
1565
1566                 kernel_wait_quiescent(kernel_tracer_fd);
1567
1568                 ksession->started = 0;
1569         }
1570
1571         if (usess) {
1572                 usess->start_trace = 0;
1573
1574                 ret = ust_app_stop_trace_all(usess);
1575                 if (ret < 0) {
1576                         ret = LTTNG_ERR_UST_STOP_FAIL;
1577                         goto error;
1578                 }
1579         }
1580
1581         session->started = 0;
1582
1583         ret = LTTNG_OK;
1584
1585 error:
1586         return ret;
1587 }
1588
1589 /*
1590  * Command LTTNG_SET_CONSUMER_URI processed by the client thread.
1591  */
1592 int cmd_set_consumer_uri(int domain, struct ltt_session *session,
1593                 size_t nb_uri, struct lttng_uri *uris)
1594 {
1595         int ret, i;
1596         struct ltt_kernel_session *ksess = session->kernel_session;
1597         struct ltt_ust_session *usess = session->ust_session;
1598         struct consumer_output *consumer = NULL;
1599
1600         assert(session);
1601         assert(uris);
1602         assert(nb_uri > 0);
1603
1604         /* Can't enable consumer after session started. */
1605         if (session->enabled) {
1606                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
1607                 goto error;
1608         }
1609
1610         /*
1611          * This case switch makes sure the domain session has a temporary consumer
1612          * so the URL can be set.
1613          */
1614         switch (domain) {
1615         case 0:
1616                 /* Code flow error. A session MUST always have a consumer object */
1617                 assert(session->consumer);
1618                 /*
1619                  * The URL will be added to the tracing session consumer instead of a
1620                  * specific domain consumer.
1621                  */
1622                 consumer = session->consumer;
1623                 break;
1624         case LTTNG_DOMAIN_KERNEL:
1625                 /* Code flow error if we don't have a kernel session here. */
1626                 assert(ksess);
1627
1628                 /* Create consumer output if none exists */
1629                 consumer = ksess->tmp_consumer;
1630                 if (consumer == NULL) {
1631                         consumer = consumer_copy_output(ksess->consumer);
1632                         if (consumer == NULL) {
1633                                 ret = LTTNG_ERR_FATAL;
1634                                 goto error;
1635                         }
1636                         /* Trash the consumer subdir, we are about to set a new one. */
1637                         memset(consumer->subdir, 0, sizeof(consumer->subdir));
1638                         ksess->tmp_consumer = consumer;
1639                 }
1640
1641                 break;
1642         case LTTNG_DOMAIN_UST:
1643                 /* Code flow error if we don't have a kernel session here. */
1644                 assert(usess);
1645
1646                 /* Create consumer output if none exists */
1647                 consumer = usess->tmp_consumer;
1648                 if (consumer == NULL) {
1649                         consumer = consumer_copy_output(usess->consumer);
1650                         if (consumer == NULL) {
1651                                 ret = LTTNG_ERR_FATAL;
1652                                 goto error;
1653                         }
1654                         /* Trash the consumer subdir, we are about to set a new one. */
1655                         memset(consumer->subdir, 0, sizeof(consumer->subdir));
1656                         usess->tmp_consumer = consumer;
1657                 }
1658
1659                 break;
1660         }
1661
1662         for (i = 0; i < nb_uri; i++) {
1663                 struct consumer_socket *socket;
1664                 struct lttng_ht_iter iter;
1665
1666                 ret = add_uri_to_consumer(consumer, &uris[i], domain, session->name);
1667                 if (ret < 0) {
1668                         goto error;
1669                 }
1670
1671                 /*
1672                  * Don't send relayd socket if URI is NOT remote or if the relayd
1673                  * socket for the session was already sent.
1674                  */
1675                 if (uris[i].dtype == LTTNG_DST_PATH ||
1676                                 (uris[i].stype == LTTNG_STREAM_CONTROL &&
1677                                 consumer->dst.net.control_sock_sent) ||
1678                                 (uris[i].stype == LTTNG_STREAM_DATA &&
1679                                 consumer->dst.net.data_sock_sent)) {
1680                         continue;
1681                 }
1682
1683                 /* Try to send relayd URI to the consumer if exist. */
1684                 rcu_read_lock();
1685                 cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter,
1686                                 socket, node.node) {
1687
1688                         /* A socket in the HT should never have a negative fd */
1689                         assert(socket->fd >= 0);
1690
1691                         pthread_mutex_lock(socket->lock);
1692                         ret = send_consumer_relayd_socket(domain, session, &uris[i],
1693                                         consumer, socket->fd);
1694                         pthread_mutex_unlock(socket->lock);
1695                         if (ret != LTTNG_OK) {
1696                                 rcu_read_unlock();
1697                                 goto error;
1698                         }
1699                 }
1700                 rcu_read_unlock();
1701         }
1702
1703         /* All good! */
1704         ret = LTTNG_OK;
1705
1706 error:
1707         return ret;
1708 }
1709
1710 /*
1711  * Command LTTNG_CREATE_SESSION processed by the client thread.
1712  */
1713 int cmd_create_session_uri(char *name, struct lttng_uri *uris,
1714                 size_t nb_uri, lttng_sock_cred *creds)
1715 {
1716         int ret;
1717         char *path = NULL;
1718         struct ltt_session *session;
1719
1720         assert(name);
1721
1722         /*
1723          * Verify if the session already exist
1724          *
1725          * XXX: There is no need for the session lock list here since the caller
1726          * (process_client_msg) is holding it. We might want to change that so a
1727          * single command does not lock the entire session list.
1728          */
1729         session = session_find_by_name(name);
1730         if (session != NULL) {
1731                 ret = LTTNG_ERR_EXIST_SESS;
1732                 goto find_error;
1733         }
1734
1735         /* Create tracing session in the registry */
1736         ret = session_create(name, path, LTTNG_SOCK_GET_UID_CRED(creds),
1737                         LTTNG_SOCK_GET_GID_CRED(creds));
1738         if (ret != LTTNG_OK) {
1739                 goto session_error;
1740         }
1741
1742         /*
1743          * Get the newly created session pointer back
1744          *
1745          * XXX: There is no need for the session lock list here since the caller
1746          * (process_client_msg) is holding it. We might want to change that so a
1747          * single command does not lock the entire session list.
1748          */
1749         session = session_find_by_name(name);
1750         assert(session);
1751
1752         /* Create default consumer output for the session not yet created. */
1753         session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
1754         if (session->consumer == NULL) {
1755                 ret = LTTNG_ERR_FATAL;
1756                 goto consumer_error;
1757         }
1758
1759         /*
1760          * This means that the lttng_create_session call was called with the _path_
1761          * argument set to NULL.
1762          */
1763         if (uris == NULL) {
1764                 /*
1765                  * At this point, we'll skip the consumer URI setup and create a
1766                  * session with a NULL path which will flag the session to NOT spawn a
1767                  * consumer.
1768                  */
1769                 DBG("Create session %s with NO uri, skipping consumer setup", name);
1770                 goto end;
1771         }
1772
1773         session->start_consumer = 1;
1774
1775         ret = cmd_set_consumer_uri(0, session, nb_uri, uris);
1776         if (ret != LTTNG_OK) {
1777                 goto consumer_error;
1778         }
1779
1780         session->consumer->enabled = 1;
1781
1782 end:
1783         return LTTNG_OK;
1784
1785 consumer_error:
1786         session_destroy(session);
1787 session_error:
1788 find_error:
1789         return ret;
1790 }
1791
1792 /*
1793  * Command LTTNG_DESTROY_SESSION processed by the client thread.
1794  */
1795 int cmd_destroy_session(struct ltt_session *session, int wpipe)
1796 {
1797         int ret;
1798         struct ltt_ust_session *usess;
1799         struct ltt_kernel_session *ksess;
1800
1801         /* Safety net */
1802         assert(session);
1803
1804         usess = session->ust_session;
1805         ksess = session->kernel_session;
1806
1807         /* Clean kernel session teardown */
1808         kernel_destroy_session(ksess);
1809
1810         /* UST session teardown */
1811         if (usess) {
1812                 /* Close any relayd session */
1813                 consumer_output_send_destroy_relayd(usess->consumer);
1814
1815                 /* Destroy every UST application related to this session. */
1816                 ret = ust_app_destroy_trace_all(usess);
1817                 if (ret) {
1818                         ERR("Error in ust_app_destroy_trace_all");
1819                 }
1820
1821                 /* Clean up the rest. */
1822                 trace_ust_destroy_session(usess);
1823         }
1824
1825         /*
1826          * Must notify the kernel thread here to update it's poll set in order to
1827          * remove the channel(s)' fd just destroyed.
1828          */
1829         ret = notify_thread_pipe(wpipe);
1830         if (ret < 0) {
1831                 PERROR("write kernel poll pipe");
1832         }
1833
1834         ret = session_destroy(session);
1835
1836         return ret;
1837 }
1838
1839 /*
1840  * Command LTTNG_CALIBRATE processed by the client thread.
1841  */
1842 int cmd_calibrate(int domain, struct lttng_calibrate *calibrate)
1843 {
1844         int ret;
1845
1846         switch (domain) {
1847         case LTTNG_DOMAIN_KERNEL:
1848         {
1849                 struct lttng_kernel_calibrate kcalibrate;
1850
1851                 kcalibrate.type = calibrate->type;
1852                 ret = kernel_calibrate(kernel_tracer_fd, &kcalibrate);
1853                 if (ret < 0) {
1854                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1855                         goto error;
1856                 }
1857                 break;
1858         }
1859         case LTTNG_DOMAIN_UST:
1860         {
1861                 struct lttng_ust_calibrate ucalibrate;
1862
1863                 ucalibrate.type = calibrate->type;
1864                 ret = ust_app_calibrate_glb(&ucalibrate);
1865                 if (ret < 0) {
1866                         ret = LTTNG_ERR_UST_CALIBRATE_FAIL;
1867                         goto error;
1868                 }
1869                 break;
1870         }
1871         default:
1872                 ret = LTTNG_ERR_UND;
1873                 goto error;
1874         }
1875
1876         ret = LTTNG_OK;
1877
1878 error:
1879         return ret;
1880 }
1881
1882 /*
1883  * Command LTTNG_REGISTER_CONSUMER processed by the client thread.
1884  */
1885 int cmd_register_consumer(struct ltt_session *session, int domain,
1886                 const char *sock_path, struct consumer_data *cdata)
1887 {
1888         int ret, sock;
1889         struct consumer_socket *socket;
1890
1891         assert(session);
1892         assert(cdata);
1893         assert(sock_path);
1894
1895         switch (domain) {
1896         case LTTNG_DOMAIN_KERNEL:
1897         {
1898                 struct ltt_kernel_session *ksess = session->kernel_session;
1899
1900                 assert(ksess);
1901
1902                 /* Can't register a consumer if there is already one */
1903                 if (ksess->consumer_fds_sent != 0) {
1904                         ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
1905                         goto error;
1906                 }
1907
1908                 sock = lttcomm_connect_unix_sock(sock_path);
1909                 if (sock < 0) {
1910                         ret = LTTNG_ERR_CONNECT_FAIL;
1911                         goto error;
1912                 }
1913
1914                 socket = consumer_allocate_socket(sock);
1915                 if (socket == NULL) {
1916                         ret = LTTNG_ERR_FATAL;
1917                         close(sock);
1918                         goto error;
1919                 }
1920
1921                 socket->lock = zmalloc(sizeof(pthread_mutex_t));
1922                 if (socket->lock == NULL) {
1923                         PERROR("zmalloc pthread mutex");
1924                         ret = LTTNG_ERR_FATAL;
1925                         goto error;
1926                 }
1927                 pthread_mutex_init(socket->lock, NULL);
1928                 socket->registered = 1;
1929
1930                 rcu_read_lock();
1931                 consumer_add_socket(socket, ksess->consumer);
1932                 rcu_read_unlock();
1933
1934                 pthread_mutex_lock(&cdata->pid_mutex);
1935                 cdata->pid = -1;
1936                 pthread_mutex_unlock(&cdata->pid_mutex);
1937
1938                 break;
1939         }
1940         default:
1941                 /* TODO: Userspace tracing */
1942                 ret = LTTNG_ERR_UND;
1943                 goto error;
1944         }
1945
1946         ret = LTTNG_OK;
1947
1948 error:
1949         return ret;
1950 }
1951
1952 /*
1953  * Command LTTNG_LIST_DOMAINS processed by the client thread.
1954  */
1955 ssize_t cmd_list_domains(struct ltt_session *session,
1956                 struct lttng_domain **domains)
1957 {
1958         int ret, index = 0;
1959         ssize_t nb_dom = 0;
1960
1961         if (session->kernel_session != NULL) {
1962                 DBG3("Listing domains found kernel domain");
1963                 nb_dom++;
1964         }
1965
1966         if (session->ust_session != NULL) {
1967                 DBG3("Listing domains found UST global domain");
1968                 nb_dom++;
1969         }
1970
1971         *domains = zmalloc(nb_dom * sizeof(struct lttng_domain));
1972         if (*domains == NULL) {
1973                 ret = LTTNG_ERR_FATAL;
1974                 goto error;
1975         }
1976
1977         if (session->kernel_session != NULL) {
1978                 (*domains)[index].type = LTTNG_DOMAIN_KERNEL;
1979                 index++;
1980         }
1981
1982         if (session->ust_session != NULL) {
1983                 (*domains)[index].type = LTTNG_DOMAIN_UST;
1984                 index++;
1985         }
1986
1987         return nb_dom;
1988
1989 error:
1990         /* Return negative value to differentiate return code */
1991         return -ret;
1992 }
1993
1994
1995 /*
1996  * Command LTTNG_LIST_CHANNELS processed by the client thread.
1997  */
1998 ssize_t cmd_list_channels(int domain, struct ltt_session *session,
1999                 struct lttng_channel **channels)
2000 {
2001         int ret;
2002         ssize_t nb_chan = 0;
2003
2004         switch (domain) {
2005         case LTTNG_DOMAIN_KERNEL:
2006                 if (session->kernel_session != NULL) {
2007                         nb_chan = session->kernel_session->channel_count;
2008                 }
2009                 DBG3("Number of kernel channels %zd", nb_chan);
2010                 if (nb_chan <= 0) {
2011                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
2012                 }
2013                 break;
2014         case LTTNG_DOMAIN_UST:
2015                 if (session->ust_session != NULL) {
2016                         nb_chan = lttng_ht_get_count(
2017                                         session->ust_session->domain_global.channels);
2018                 }
2019                 DBG3("Number of UST global channels %zd", nb_chan);
2020                 if (nb_chan <= 0) {
2021                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
2022                 }
2023                 break;
2024         default:
2025                 *channels = NULL;
2026                 ret = LTTNG_ERR_UND;
2027                 goto error;
2028         }
2029
2030         if (nb_chan > 0) {
2031                 *channels = zmalloc(nb_chan * sizeof(struct lttng_channel));
2032                 if (*channels == NULL) {
2033                         ret = LTTNG_ERR_FATAL;
2034                         goto error;
2035                 }
2036
2037                 list_lttng_channels(domain, session, *channels);
2038         } else {
2039                 *channels = NULL;
2040                 /* Ret value was set in the domain switch case */
2041                 goto error;
2042         }
2043
2044         return nb_chan;
2045
2046 error:
2047         /* Return negative value to differentiate return code */
2048         return -ret;
2049 }
2050
2051 /*
2052  * Command LTTNG_LIST_EVENTS processed by the client thread.
2053  */
2054 ssize_t cmd_list_events(int domain, struct ltt_session *session,
2055                 char *channel_name, struct lttng_event **events)
2056 {
2057         int ret = 0;
2058         ssize_t nb_event = 0;
2059
2060         switch (domain) {
2061         case LTTNG_DOMAIN_KERNEL:
2062                 if (session->kernel_session != NULL) {
2063                         nb_event = list_lttng_kernel_events(channel_name,
2064                                         session->kernel_session, events);
2065                 }
2066                 break;
2067         case LTTNG_DOMAIN_UST:
2068         {
2069                 if (session->ust_session != NULL) {
2070                         nb_event = list_lttng_ust_global_events(channel_name,
2071                                         &session->ust_session->domain_global, events);
2072                 }
2073                 break;
2074         }
2075         default:
2076                 ret = LTTNG_ERR_UND;
2077                 goto error;
2078         }
2079
2080         return nb_event;
2081
2082 error:
2083         /* Return negative value to differentiate return code */
2084         return -ret;
2085 }
2086
2087 /*
2088  * Using the session list, filled a lttng_session array to send back to the
2089  * client for session listing.
2090  *
2091  * The session list lock MUST be acquired before calling this function. Use
2092  * session_lock_list() and session_unlock_list().
2093  */
2094 void cmd_list_lttng_sessions(struct lttng_session *sessions, uid_t uid,
2095                 gid_t gid)
2096 {
2097         int ret;
2098         unsigned int i = 0;
2099         struct ltt_session *session;
2100         struct ltt_session_list *list = session_get_list();
2101
2102         DBG("Getting all available session for UID %d GID %d",
2103                         uid, gid);
2104         /*
2105          * Iterate over session list and append data after the control struct in
2106          * the buffer.
2107          */
2108         cds_list_for_each_entry(session, &list->head, list) {
2109                 /*
2110                  * Only list the sessions the user can control.
2111                  */
2112                 if (!session_access_ok(session, uid, gid)) {
2113                         continue;
2114                 }
2115
2116                 struct ltt_kernel_session *ksess = session->kernel_session;
2117                 struct ltt_ust_session *usess = session->ust_session;
2118
2119                 if (session->consumer->type == CONSUMER_DST_NET ||
2120                                 (ksess && ksess->consumer->type == CONSUMER_DST_NET) ||
2121                                 (usess && usess->consumer->type == CONSUMER_DST_NET)) {
2122                         ret = build_network_session_path(sessions[i].path,
2123                                         sizeof(session[i].path), session);
2124                 } else {
2125                         ret = snprintf(sessions[i].path, sizeof(session[i].path), "%s",
2126                                         session->consumer->dst.trace_path);
2127                 }
2128                 if (ret < 0) {
2129                         PERROR("snprintf session path");
2130                         continue;
2131                 }
2132
2133                 strncpy(sessions[i].name, session->name, NAME_MAX);
2134                 sessions[i].name[NAME_MAX - 1] = '\0';
2135                 sessions[i].enabled = session->enabled;
2136                 i++;
2137         }
2138 }
2139
2140 /*
2141  * Command LTTNG_DISABLE_CONSUMER processed by the client thread.
2142  */
2143 int cmd_disable_consumer(int domain, struct ltt_session *session)
2144 {
2145         int ret;
2146         struct ltt_kernel_session *ksess = session->kernel_session;
2147         struct ltt_ust_session *usess = session->ust_session;
2148         struct consumer_output *consumer;
2149
2150         assert(session);
2151
2152         if (session->enabled) {
2153                 /* Can't disable consumer on an already started session */
2154                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2155                 goto error;
2156         }
2157
2158         if (!session->start_consumer) {
2159                 ret = LTTNG_ERR_NO_CONSUMER;
2160                 goto error;
2161         }
2162
2163         switch (domain) {
2164         case 0:
2165                 DBG("Disable tracing session %s consumer", session->name);
2166                 consumer = session->consumer;
2167                 break;
2168         case LTTNG_DOMAIN_KERNEL:
2169                 /* Code flow error if we don't have a kernel session here. */
2170                 assert(ksess);
2171
2172                 DBG("Disabling kernel consumer");
2173                 consumer = ksess->consumer;
2174
2175                 break;
2176         case LTTNG_DOMAIN_UST:
2177                 /* Code flow error if we don't have a UST session here. */
2178                 assert(usess);
2179
2180                 DBG("Disabling UST consumer");
2181                 consumer = usess->consumer;
2182
2183                 break;
2184         default:
2185                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
2186                 goto error;
2187         }
2188
2189         if (consumer) {
2190                 consumer->enabled = 0;
2191                 /* Success at this point */
2192                 ret = LTTNG_OK;
2193         } else {
2194                 ret = LTTNG_ERR_NO_CONSUMER;
2195         }
2196
2197 error:
2198         return ret;
2199 }
2200
2201 /*
2202  * Command LTTNG_ENABLE_CONSUMER processed by the client thread.
2203  */
2204 int cmd_enable_consumer(int domain, struct ltt_session *session)
2205 {
2206         int ret;
2207         struct ltt_kernel_session *ksess = session->kernel_session;
2208         struct ltt_ust_session *usess = session->ust_session;
2209         struct consumer_output *consumer = NULL;
2210
2211         assert(session);
2212
2213         /* Can't enable consumer after session started. */
2214         if (session->enabled) {
2215                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2216                 goto error;
2217         }
2218
2219         switch (domain) {
2220         case 0:
2221                 assert(session->consumer);
2222                 consumer = session->consumer;
2223                 break;
2224         case LTTNG_DOMAIN_KERNEL:
2225                 /* Code flow error if we don't have a kernel session here. */
2226                 assert(ksess);
2227
2228                 /*
2229                  * Check if we have already sent fds to the consumer. In that case,
2230                  * the enable-consumer command can't be used because a start trace
2231                  * had previously occured.
2232                  */
2233                 if (ksess->consumer_fds_sent) {
2234                         ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2235                         goto error;
2236                 }
2237
2238                 consumer = ksess->tmp_consumer;
2239                 if (consumer == NULL) {
2240                         ret = LTTNG_OK;
2241                         /* No temp. consumer output exists. Using the current one. */
2242                         DBG3("No temporary consumer. Using default");
2243                         consumer = ksess->consumer;
2244                         goto error;
2245                 }
2246
2247                 switch (consumer->type) {
2248                 case CONSUMER_DST_LOCAL:
2249                         DBG2("Consumer output is local. Creating directory(ies)");
2250
2251                         /* Create directory(ies) */
2252                         ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2253                                         S_IRWXU | S_IRWXG, session->uid, session->gid);
2254                         if (ret < 0) {
2255                                 if (ret != -EEXIST) {
2256                                         ERR("Trace directory creation error");
2257                                         ret = LTTNG_ERR_FATAL;
2258                                         goto error;
2259                                 }
2260                         }
2261                         break;
2262                 case CONSUMER_DST_NET:
2263                         DBG2("Consumer output is network. Validating URIs");
2264                         /* Validate if we have both control and data path set. */
2265                         if (!consumer->dst.net.control_isset) {
2266                                 ret = LTTNG_ERR_URL_CTRL_MISS;
2267                                 goto error;
2268                         }
2269
2270                         if (!consumer->dst.net.data_isset) {
2271                                 ret = LTTNG_ERR_URL_DATA_MISS;
2272                                 goto error;
2273                         }
2274
2275                         /* Check established network session state */
2276                         if (session->net_handle == 0) {
2277                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2278                                 ERR("Session network handle is not set on enable-consumer");
2279                                 goto error;
2280                         }
2281
2282                         break;
2283                 }
2284
2285                 /*
2286                  * @session-lock
2287                  * This is race free for now since the session lock is acquired before
2288                  * ending up in this function. No other threads can access this kernel
2289                  * session without this lock hence freeing the consumer output object
2290                  * is valid.
2291                  */
2292                 rcu_read_lock();
2293                 /* Destroy current consumer. We are about to replace it */
2294                 consumer_destroy_output(ksess->consumer);
2295                 rcu_read_unlock();
2296                 ksess->consumer = consumer;
2297                 ksess->tmp_consumer = NULL;
2298
2299                 break;
2300         case LTTNG_DOMAIN_UST:
2301                 /* Code flow error if we don't have a UST session here. */
2302                 assert(usess);
2303
2304                 /*
2305                  * Check if we have already sent fds to the consumer. In that case,
2306                  * the enable-consumer command can't be used because a start trace
2307                  * had previously occured.
2308                  */
2309                 if (usess->start_trace) {
2310                         ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2311                         goto error;
2312                 }
2313
2314                 consumer = usess->tmp_consumer;
2315                 if (consumer == NULL) {
2316                         ret = LTTNG_OK;
2317                         /* No temp. consumer output exists. Using the current one. */
2318                         DBG3("No temporary consumer. Using default");
2319                         consumer = usess->consumer;
2320                         goto error;
2321                 }
2322
2323                 switch (consumer->type) {
2324                 case CONSUMER_DST_LOCAL:
2325                         DBG2("Consumer output is local. Creating directory(ies)");
2326
2327                         /* Create directory(ies) */
2328                         ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2329                                         S_IRWXU | S_IRWXG, session->uid, session->gid);
2330                         if (ret < 0) {
2331                                 if (ret != -EEXIST) {
2332                                         ERR("Trace directory creation error");
2333                                         ret = LTTNG_ERR_FATAL;
2334                                         goto error;
2335                                 }
2336                         }
2337                         break;
2338                 case CONSUMER_DST_NET:
2339                         DBG2("Consumer output is network. Validating URIs");
2340                         /* Validate if we have both control and data path set. */
2341                         if (!consumer->dst.net.control_isset) {
2342                                 ret = LTTNG_ERR_URL_CTRL_MISS;
2343                                 goto error;
2344                         }
2345
2346                         if (!consumer->dst.net.data_isset) {
2347                                 ret = LTTNG_ERR_URL_DATA_MISS;
2348                                 goto error;
2349                         }
2350
2351                         /* Check established network session state */
2352                         if (session->net_handle == 0) {
2353                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2354                                 DBG2("Session network handle is not set on enable-consumer");
2355                                 goto error;
2356                         }
2357
2358                         if (consumer->net_seq_index == -1) {
2359                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2360                                 DBG2("Network index is not set on the consumer");
2361                                 goto error;
2362                         }
2363
2364                         break;
2365                 }
2366
2367                 /*
2368                  * @session-lock
2369                  * This is race free for now since the session lock is acquired before
2370                  * ending up in this function. No other threads can access this kernel
2371                  * session without this lock hence freeing the consumer output object
2372                  * is valid.
2373                  */
2374                 rcu_read_lock();
2375                 /* Destroy current consumer. We are about to replace it */
2376                 consumer_destroy_output(usess->consumer);
2377                 rcu_read_unlock();
2378                 usess->consumer = consumer;
2379                 usess->tmp_consumer = NULL;
2380
2381                 break;
2382         }
2383
2384         session->start_consumer = 1;
2385
2386         /* Enable it */
2387         if (consumer) {
2388                 consumer->enabled = 1;
2389                 /* Success at this point */
2390                 ret = LTTNG_OK;
2391         } else {
2392                 /* Should not really happend... */
2393                 ret = LTTNG_ERR_NO_CONSUMER;
2394         }
2395
2396 error:
2397         return ret;
2398 }
2399
2400 /*
2401  * Command LTTNG_DATA_PENDING returning 0 if the data is NOT pending meaning
2402  * ready for trace analysis (or anykind of reader) or else 1 for pending data.
2403  */
2404 int cmd_data_pending(struct ltt_session *session)
2405 {
2406         int ret;
2407         struct ltt_kernel_session *ksess = session->kernel_session;
2408         struct ltt_ust_session *usess = session->ust_session;
2409
2410         assert(session);
2411
2412         /* Session MUST be stopped to ask for data availability. */
2413         if (session->enabled) {
2414                 ret = LTTNG_ERR_SESSION_STARTED;
2415                 goto error;
2416         }
2417
2418         if (ksess && ksess->consumer) {
2419                 ret = consumer_is_data_pending(ksess->id, ksess->consumer);
2420                 if (ret == 1) {
2421                         /* Data is still being extracted for the kernel. */
2422                         goto error;
2423                 }
2424         }
2425
2426         if (usess && usess->consumer) {
2427                 ret = consumer_is_data_pending(usess->id, usess->consumer);
2428                 if (ret == 1) {
2429                         /* Data is still being extracted for the kernel. */
2430                         goto error;
2431                 }
2432         }
2433
2434         /* Data is ready to be read by a viewer */
2435         ret = 0;
2436
2437 error:
2438         return ret;
2439 }
2440
2441 /*
2442  * Init command subsystem.
2443  */
2444 void cmd_init(void)
2445 {
2446         /*
2447          * Set network sequence index to 1 for streams to match a relayd socket on
2448          * the consumer side.
2449          */
2450         uatomic_set(&relayd_net_seq_idx, 1);
2451
2452         DBG("Command subsystem initialized");
2453 }