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         /* Don't resend the sockets to the consumer. */
 526         if (consumer->dst.net.relayd_socks_sent) {
 527                 ret = LTTNG_OK;
 528                 goto error;
 529         }
 530
 531         /* Set the network sequence index if not set. */
 532         if (consumer->net_seq_index == -1) {
 533                 /*
 534                  * Increment net_seq_idx because we are about to transfer the
 535                  * new relayd socket to the consumer.
 536                  */
 537                 uatomic_inc(&relayd_net_seq_idx);
 538                 /* Assign unique key so the consumer can match streams */
 539                 uatomic_set(&consumer->net_seq_index,
 540                                 uatomic_read(&relayd_net_seq_idx));
 541         }
 542
 543         /* Connect to relayd and make version check if uri is the control. */
 544         ret = create_connect_relayd(consumer, session->name, relayd_uri, &sock);
 545         if (ret != LTTNG_OK) {
 546                 goto close_sock;
 547         }
 548
 549         /* If the control socket is connected, network session is ready */
 550         if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
 551                 session->net_handle = 1;
 552         }
 553
 554         /* Send relayd socket to consumer. */
 555         ret = consumer_send_relayd_socket(consumer_fd, sock,
 556                         consumer, relayd_uri->stype);
 557         if (ret < 0) {
 558                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
 559                 goto close_sock;
 560         }
 561
 562         ret = LTTNG_OK;
 563
 564         /*
 565          * Close socket which was dup on the consumer side. The session daemon does
 566          * NOT keep track of the relayd socket(s) once transfer to the consumer.
 567          */
 568
 569 close_sock:
 570         if (sock) {
 571                 (void) relayd_close(sock);
 572                 lttcomm_destroy_sock(sock);
 573         }
 574
 575 error:
 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;
 588
 589         assert(session);
 590         assert(consumer);
 591
 592         /* Don't resend the sockets to the consumer. */
 593         if (consumer->dst.net.relayd_socks_sent) {
 594                 ret = LTTNG_OK;
 595                 goto error;
 596         }
 597
 598         /* Sending control relayd socket. */
 599         ret = send_consumer_relayd_socket(domain, session,
 600                         &consumer->dst.net.control, consumer, fd);
 601         if (ret != LTTNG_OK) {
 602                 goto error;
 603         }
 604
 605         /* Sending data relayd socket. */
 606         ret = send_consumer_relayd_socket(domain, session,
 607                         &consumer->dst.net.data, consumer, fd);
 608         if (ret != LTTNG_OK) {
 609                 goto error;
 610         }
 611
 612         /* Flag that all relayd sockets were sent to the consumer. */
 613         consumer->dst.net.relayd_socks_sent = 1;
 614
 615 error:
 616         return ret;
 617 }
 618
 619 /*
 620  * Setup relayd connections for a tracing session. First creates the socket to
 621  * the relayd and send them to the right domain consumer. Consumer type MUST be
 622  * network.
 623  */
 624 static int setup_relayd(struct ltt_session *session)
 625 {
 626         int ret = LTTNG_OK;
 627         struct ltt_ust_session *usess;
 628         struct ltt_kernel_session *ksess;
 629         struct consumer_socket *socket;
 630         struct lttng_ht_iter iter;
 631
 632         assert(session);
 633
 634         usess = session->ust_session;
 635         ksess = session->kernel_session;
 636
 637         DBG2("Setting relayd for session %s", session->name);
 638
 639         if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
 640                         && usess->consumer->enabled) {
 641                 /* For each consumer socket, send relayd sockets */
 642                 cds_lfht_for_each_entry(usess->consumer->socks->ht, &iter.iter,
 643                                 socket, node.node) {
 644                         /* Code flow error */
 645                         assert(socket->fd >= 0);
 646
 647                         pthread_mutex_lock(socket->lock);
 648                         send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session,
 649                                         usess->consumer, socket->fd);
 650                         pthread_mutex_unlock(socket->lock);
 651                         if (ret != LTTNG_OK) {
 652                                 goto error;
 653                         }
 654                 }
 655         }
 656
 657         if (ksess && ksess->consumer && ksess->consumer->type == CONSUMER_DST_NET
 658                         && ksess->consumer->enabled) {
 659                 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
 660                                 socket, node.node) {
 661                         /* Code flow error */
 662                         assert(socket->fd >= 0);
 663
 664                         pthread_mutex_lock(socket->lock);
 665                         send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session,
 666                                         ksess->consumer, socket->fd);
 667                         pthread_mutex_unlock(socket->lock);
 668                         if (ret != LTTNG_OK) {
 669                                 goto error;
 670                         }
 671                 }
 672         }
 673
 674 error:
 675         return ret;
 676 }
 677
 678 /*
 679  * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
 680  */
 681 int cmd_disable_channel(struct ltt_session *session, int domain,
 682                 char *channel_name)
 683 {
 684         int ret;
 685         struct ltt_ust_session *usess;
 686
 687         usess = session->ust_session;
 688
 689         switch (domain) {
 690         case LTTNG_DOMAIN_KERNEL:
 691         {
 692                 ret = channel_kernel_disable(session->kernel_session,
 693                                 channel_name);
 694                 if (ret != LTTNG_OK) {
 695                         goto error;
 696                 }
 697
 698                 kernel_wait_quiescent(kernel_tracer_fd);
 699                 break;
 700         }
 701         case LTTNG_DOMAIN_UST:
 702         {
 703                 struct ltt_ust_channel *uchan;
 704                 struct lttng_ht *chan_ht;
 705
 706                 chan_ht = usess->domain_global.channels;
 707
 708                 uchan = trace_ust_find_channel_by_name(chan_ht, channel_name);
 709                 if (uchan == NULL) {
 710                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 711                         goto error;
 712                 }
 713
 714                 ret = channel_ust_disable(usess, domain, uchan);
 715                 if (ret != LTTNG_OK) {
 716                         goto error;
 717                 }
 718                 break;
 719         }
 720 #if 0
 721         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 722         case LTTNG_DOMAIN_UST_EXEC_NAME:
 723         case LTTNG_DOMAIN_UST_PID:
 724 #endif
 725         default:
 726                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
 727                 goto error;
 728         }
 729
 730         ret = LTTNG_OK;
 731
 732 error:
 733         return ret;
 734 }
 735
 736 /*
 737  * Command LTTNG_ENABLE_CHANNEL processed by the client thread.
 738  *
 739  * The wpipe arguments is used as a notifier for the kernel thread.
 740  */
 741 int cmd_enable_channel(struct ltt_session *session,
 742                 int domain, struct lttng_channel *attr, int wpipe)
 743 {
 744         int ret;
 745         struct ltt_ust_session *usess = session->ust_session;
 746         struct lttng_ht *chan_ht;
 747
 748         assert(session);
 749         assert(attr);
 750
 751         DBG("Enabling channel %s for session %s", attr->name, session->name);
 752
 753         switch (domain) {
 754         case LTTNG_DOMAIN_KERNEL:
 755         {
 756                 struct ltt_kernel_channel *kchan;
 757
 758                 /* Mandatory for a kernel channel. */
 759                 assert(wpipe > 0);
 760
 761                 kchan = trace_kernel_get_channel_by_name(attr->name,
 762                                 session->kernel_session);
 763                 if (kchan == NULL) {
 764                         ret = channel_kernel_create(session->kernel_session, attr, wpipe);
 765                 } else {
 766                         ret = channel_kernel_enable(session->kernel_session, kchan);
 767                 }
 768
 769                 if (ret != LTTNG_OK) {
 770                         goto error;
 771                 }
 772
 773                 kernel_wait_quiescent(kernel_tracer_fd);
 774                 break;
 775         }
 776         case LTTNG_DOMAIN_UST:
 777         {
 778                 struct ltt_ust_channel *uchan;
 779
 780                 chan_ht = usess->domain_global.channels;
 781
 782                 uchan = trace_ust_find_channel_by_name(chan_ht, attr->name);
 783                 if (uchan == NULL) {
 784                         ret = channel_ust_create(usess, domain, attr);
 785                 } else {
 786                         ret = channel_ust_enable(usess, domain, uchan);
 787                 }
 788                 break;
 789         }
 790 #if 0
 791         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 792         case LTTNG_DOMAIN_UST_EXEC_NAME:
 793         case LTTNG_DOMAIN_UST_PID:
 794 #endif
 795         default:
 796                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
 797                 goto error;
 798         }
 799
 800 error:
 801         return ret;
 802 }
 803
 804
 805 /*
 806  * Command LTTNG_DISABLE_EVENT processed by the client thread.
 807  */
 808 int cmd_disable_event(struct ltt_session *session, int domain,
 809                 char *channel_name, char *event_name)
 810 {
 811         int ret;
 812
 813         switch (domain) {
 814         case LTTNG_DOMAIN_KERNEL:
 815         {
 816                 struct ltt_kernel_channel *kchan;
 817                 struct ltt_kernel_session *ksess;
 818
 819                 ksess = session->kernel_session;
 820
 821                 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
 822                 if (kchan == NULL) {
 823                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 824                         goto error;
 825                 }
 826
 827                 ret = event_kernel_disable_tracepoint(ksess, kchan, event_name);
 828                 if (ret != LTTNG_OK) {
 829                         goto error;
 830                 }
 831
 832                 kernel_wait_quiescent(kernel_tracer_fd);
 833                 break;
 834         }
 835         case LTTNG_DOMAIN_UST:
 836         {
 837                 struct ltt_ust_channel *uchan;
 838                 struct ltt_ust_session *usess;
 839
 840                 usess = session->ust_session;
 841
 842                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 843                                 channel_name);
 844                 if (uchan == NULL) {
 845                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 846                         goto error;
 847                 }
 848
 849                 ret = event_ust_disable_tracepoint(usess, domain, uchan, event_name);
 850                 if (ret != LTTNG_OK) {
 851                         goto error;
 852                 }
 853
 854                 DBG3("Disable UST event %s in channel %s completed", event_name,
 855                                 channel_name);
 856                 break;
 857         }
 858 #if 0
 859         case LTTNG_DOMAIN_UST_EXEC_NAME:
 860         case LTTNG_DOMAIN_UST_PID:
 861         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 862 #endif
 863         default:
 864                 ret = LTTNG_ERR_UND;
 865                 goto error;
 866         }
 867
 868         ret = LTTNG_OK;
 869
 870 error:
 871         return ret;
 872 }
 873
 874 /*
 875  * Command LTTNG_DISABLE_ALL_EVENT processed by the client thread.
 876  */
 877 int cmd_disable_event_all(struct ltt_session *session, int domain,
 878                 char *channel_name)
 879 {
 880         int ret;
 881
 882         switch (domain) {
 883         case LTTNG_DOMAIN_KERNEL:
 884         {
 885                 struct ltt_kernel_session *ksess;
 886                 struct ltt_kernel_channel *kchan;
 887
 888                 ksess = session->kernel_session;
 889
 890                 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
 891                 if (kchan == NULL) {
 892                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 893                         goto error;
 894                 }
 895
 896                 ret = event_kernel_disable_all(ksess, kchan);
 897                 if (ret != LTTNG_OK) {
 898                         goto error;
 899                 }
 900
 901                 kernel_wait_quiescent(kernel_tracer_fd);
 902                 break;
 903         }
 904         case LTTNG_DOMAIN_UST:
 905         {
 906                 struct ltt_ust_session *usess;
 907                 struct ltt_ust_channel *uchan;
 908
 909                 usess = session->ust_session;
 910
 911                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 912                                 channel_name);
 913                 if (uchan == NULL) {
 914                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 915                         goto error;
 916                 }
 917
 918                 ret = event_ust_disable_all_tracepoints(usess, domain, uchan);
 919                 if (ret != 0) {
 920                         goto error;
 921                 }
 922
 923                 DBG3("Disable all UST events in channel %s completed", channel_name);
 924
 925                 break;
 926         }
 927 #if 0
 928         case LTTNG_DOMAIN_UST_EXEC_NAME:
 929         case LTTNG_DOMAIN_UST_PID:
 930         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 931 #endif
 932         default:
 933                 ret = LTTNG_ERR_UND;
 934                 goto error;
 935         }
 936
 937         ret = LTTNG_OK;
 938
 939 error:
 940         return ret;
 941 }
 942
 943 /*
 944  * Command LTTNG_ADD_CONTEXT processed by the client thread.
 945  */
 946 int cmd_add_context(struct ltt_session *session, int domain,
 947                 char *channel_name, char *event_name, struct lttng_event_context *ctx)
 948 {
 949         int ret;
 950
 951         switch (domain) {
 952         case LTTNG_DOMAIN_KERNEL:
 953                 /* Add kernel context to kernel tracer */
 954                 ret = context_kernel_add(session->kernel_session, ctx,
 955                                 event_name, channel_name);
 956                 if (ret != LTTNG_OK) {
 957                         goto error;
 958                 }
 959                 break;
 960         case LTTNG_DOMAIN_UST:
 961         {
 962                 struct ltt_ust_session *usess = session->ust_session;
 963
 964                 assert(usess);
 965
 966                 ret = context_ust_add(usess, domain, ctx, event_name, channel_name);
 967                 if (ret != LTTNG_OK) {
 968                         goto error;
 969                 }
 970                 break;
 971         }
 972 #if 0
 973         case LTTNG_DOMAIN_UST_EXEC_NAME:
 974         case LTTNG_DOMAIN_UST_PID:
 975         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 976 #endif
 977         default:
 978                 ret = LTTNG_ERR_UND;
 979                 goto error;
 980         }
 981
 982         ret = LTTNG_OK;
 983
 984 error:
 985         return ret;
 986 }
 987
 988 /*
 989  * Command LTTNG_SET_FILTER processed by the client thread.
 990  */
 991 int cmd_set_filter(struct ltt_session *session, int domain,
 992                 char *channel_name, char *event_name,
 993                 struct lttng_filter_bytecode *bytecode)
 994 {
 995         int ret;
 996
 997         switch (domain) {
 998         case LTTNG_DOMAIN_KERNEL:
 999                 ret = LTTNG_ERR_FATAL;
1000                 break;
1001         case LTTNG_DOMAIN_UST:
1002         {
1003                 struct ltt_ust_session *usess = session->ust_session;
1004
1005                 ret = filter_ust_set(usess, domain, bytecode, event_name, channel_name);
1006                 if (ret != LTTNG_OK) {
1007                         goto error;
1008                 }
1009                 break;
1010         }
1011 #if 0
1012         case LTTNG_DOMAIN_UST_EXEC_NAME:
1013         case LTTNG_DOMAIN_UST_PID:
1014         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1015 #endif
1016         default:
1017                 ret = LTTNG_ERR_UND;
1018                 goto error;
1019         }
1020
1021         ret = LTTNG_OK;
1022
1023 error:
1024         return ret;
1025
1026 }
1027
1028
1029 /*
1030  * Command LTTNG_ENABLE_EVENT processed by the client thread.
1031  */
1032 int cmd_enable_event(struct ltt_session *session, int domain,
1033                 char *channel_name, struct lttng_event *event, int wpipe)
1034 {
1035         int ret;
1036         struct lttng_channel *attr;
1037
1038         assert(session);
1039         assert(event);
1040         assert(channel_name);
1041
1042         switch (domain) {
1043         case LTTNG_DOMAIN_KERNEL:
1044         {
1045                 struct ltt_kernel_channel *kchan;
1046
1047                 kchan = trace_kernel_get_channel_by_name(channel_name,
1048                                 session->kernel_session);
1049                 if (kchan == NULL) {
1050                         attr = channel_new_default_attr(domain);
1051                         if (attr == NULL) {
1052                                 ret = LTTNG_ERR_FATAL;
1053                                 goto error;
1054                         }
1055                         strncpy(attr->name, channel_name, sizeof(attr->name));
1056
1057                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1058                         if (ret != LTTNG_OK) {
1059                                 free(attr);
1060                                 goto error;
1061                         }
1062                         free(attr);
1063                 }
1064
1065                 /* Get the newly created kernel channel pointer */
1066                 kchan = trace_kernel_get_channel_by_name(channel_name,
1067                                 session->kernel_session);
1068                 if (kchan == NULL) {
1069                         /* This sould not happen... */
1070                         ret = LTTNG_ERR_FATAL;
1071                         goto error;
1072                 }
1073
1074                 ret = event_kernel_enable_tracepoint(session->kernel_session, kchan,
1075                                 event);
1076                 if (ret != LTTNG_OK) {
1077                         goto error;
1078                 }
1079
1080                 kernel_wait_quiescent(kernel_tracer_fd);
1081                 break;
1082         }
1083         case LTTNG_DOMAIN_UST:
1084         {
1085                 struct ltt_ust_channel *uchan;
1086                 struct ltt_ust_session *usess = session->ust_session;
1087
1088                 assert(usess);
1089
1090                 /* Get channel from global UST domain */
1091                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1092                                 channel_name);
1093                 if (uchan == NULL) {
1094                         /* Create default channel */
1095                         attr = channel_new_default_attr(domain);
1096                         if (attr == NULL) {
1097                                 ret = LTTNG_ERR_FATAL;
1098                                 goto error;
1099                         }
1100                         strncpy(attr->name, channel_name, sizeof(attr->name));
1101
1102                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1103                         if (ret != LTTNG_OK) {
1104                                 free(attr);
1105                                 goto error;
1106                         }
1107                         free(attr);
1108
1109                         /* Get the newly created channel reference back */
1110                         uchan = trace_ust_find_channel_by_name(
1111                                         usess->domain_global.channels, channel_name);
1112                         assert(uchan);
1113                 }
1114
1115                 /* At this point, the session and channel exist on the tracer */
1116                 ret = event_ust_enable_tracepoint(usess, domain, uchan, event);
1117                 if (ret != LTTNG_OK) {
1118                         goto error;
1119                 }
1120                 break;
1121         }
1122 #if 0
1123         case LTTNG_DOMAIN_UST_EXEC_NAME:
1124         case LTTNG_DOMAIN_UST_PID:
1125         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1126 #endif
1127         default:
1128                 ret = LTTNG_ERR_UND;
1129                 goto error;
1130         }
1131
1132         ret = LTTNG_OK;
1133
1134 error:
1135         return ret;
1136 }
1137
1138 /*
1139  * Command LTTNG_ENABLE_ALL_EVENT processed by the client thread.
1140  */
1141 int cmd_enable_event_all(struct ltt_session *session, int domain,
1142                 char *channel_name, int event_type, int wpipe)
1143 {
1144         int ret;
1145         struct lttng_channel *attr;
1146
1147         assert(session);
1148         assert(channel_name);
1149
1150         switch (domain) {
1151         case LTTNG_DOMAIN_KERNEL:
1152         {
1153                 struct ltt_kernel_channel *kchan;
1154
1155                 assert(session->kernel_session);
1156
1157                 kchan = trace_kernel_get_channel_by_name(channel_name,
1158                                 session->kernel_session);
1159                 if (kchan == NULL) {
1160                         /* Create default channel */
1161                         attr = channel_new_default_attr(domain);
1162                         if (attr == NULL) {
1163                                 ret = LTTNG_ERR_FATAL;
1164                                 goto error;
1165                         }
1166                         strncpy(attr->name, channel_name, sizeof(attr->name));
1167
1168                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1169                         if (ret != LTTNG_OK) {
1170                                 free(attr);
1171                                 goto error;
1172                         }
1173                         free(attr);
1174
1175                         /* Get the newly created kernel channel pointer */
1176                         kchan = trace_kernel_get_channel_by_name(channel_name,
1177                                         session->kernel_session);
1178                         assert(kchan);
1179                 }
1180
1181                 switch (event_type) {
1182                 case LTTNG_EVENT_SYSCALL:
1183                         ret = event_kernel_enable_all_syscalls(session->kernel_session,
1184                                         kchan, kernel_tracer_fd);
1185                         break;
1186                 case LTTNG_EVENT_TRACEPOINT:
1187                         /*
1188                          * This call enables all LTTNG_KERNEL_TRACEPOINTS and
1189                          * events already registered to the channel.
1190                          */
1191                         ret = event_kernel_enable_all_tracepoints(session->kernel_session,
1192                                         kchan, kernel_tracer_fd);
1193                         break;
1194                 case LTTNG_EVENT_ALL:
1195                         /* Enable syscalls and tracepoints */
1196                         ret = event_kernel_enable_all(session->kernel_session,
1197                                         kchan, kernel_tracer_fd);
1198                         break;
1199                 default:
1200                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1201                         goto error;
1202                 }
1203
1204                 /* Manage return value */
1205                 if (ret != LTTNG_OK) {
1206                         goto error;
1207                 }
1208
1209                 kernel_wait_quiescent(kernel_tracer_fd);
1210                 break;
1211         }
1212         case LTTNG_DOMAIN_UST:
1213         {
1214                 struct ltt_ust_channel *uchan;
1215                 struct ltt_ust_session *usess = session->ust_session;
1216
1217                 assert(usess);
1218
1219                 /* Get channel from global UST domain */
1220                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1221                                 channel_name);
1222                 if (uchan == NULL) {
1223                         /* Create default channel */
1224                         attr = channel_new_default_attr(domain);
1225                         if (attr == NULL) {
1226                                 ret = LTTNG_ERR_FATAL;
1227                                 goto error;
1228                         }
1229                         strncpy(attr->name, channel_name, sizeof(attr->name));
1230
1231                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1232                         if (ret != LTTNG_OK) {
1233                                 free(attr);
1234                                 goto error;
1235                         }
1236                         free(attr);
1237
1238                         /* Get the newly created channel reference back */
1239                         uchan = trace_ust_find_channel_by_name(
1240                                         usess->domain_global.channels, channel_name);
1241                         assert(uchan);
1242                 }
1243
1244                 /* At this point, the session and channel exist on the tracer */
1245
1246                 switch (event_type) {
1247                 case LTTNG_EVENT_ALL:
1248                 case LTTNG_EVENT_TRACEPOINT:
1249                         ret = event_ust_enable_all_tracepoints(usess, domain, uchan);
1250                         if (ret != LTTNG_OK) {
1251                                 goto error;
1252                         }
1253                         break;
1254                 default:
1255                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
1256                         goto error;
1257                 }
1258
1259                 /* Manage return value */
1260                 if (ret != LTTNG_OK) {
1261                         goto error;
1262                 }
1263
1264                 break;
1265         }
1266 #if 0
1267         case LTTNG_DOMAIN_UST_EXEC_NAME:
1268         case LTTNG_DOMAIN_UST_PID:
1269         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1270 #endif
1271         default:
1272                 ret = LTTNG_ERR_UND;
1273                 goto error;
1274         }
1275
1276         ret = LTTNG_OK;
1277
1278 error:
1279         return ret;
1280 }
1281
1282
1283 /*
1284  * Command LTTNG_LIST_TRACEPOINTS processed by the client thread.
1285  */
1286 ssize_t cmd_list_tracepoints(int domain, struct lttng_event **events)
1287 {
1288         int ret;
1289         ssize_t nb_events = 0;
1290
1291         switch (domain) {
1292         case LTTNG_DOMAIN_KERNEL:
1293                 nb_events = kernel_list_events(kernel_tracer_fd, events);
1294                 if (nb_events < 0) {
1295                         ret = LTTNG_ERR_KERN_LIST_FAIL;
1296                         goto error;
1297                 }
1298                 break;
1299         case LTTNG_DOMAIN_UST:
1300                 nb_events = ust_app_list_events(events);
1301                 if (nb_events < 0) {
1302                         ret = LTTNG_ERR_UST_LIST_FAIL;
1303                         goto error;
1304                 }
1305                 break;
1306         default:
1307                 ret = LTTNG_ERR_UND;
1308                 goto error;
1309         }
1310
1311         return nb_events;
1312
1313 error:
1314         /* Return negative value to differentiate return code */
1315         return -ret;
1316 }
1317
1318 /*
1319  * Command LTTNG_LIST_TRACEPOINT_FIELDS processed by the client thread.
1320  */
1321 ssize_t cmd_list_tracepoint_fields(int domain,
1322                 struct lttng_event_field **fields)
1323 {
1324         int ret;
1325         ssize_t nb_fields = 0;
1326
1327         switch (domain) {
1328         case LTTNG_DOMAIN_UST:
1329                 nb_fields = ust_app_list_event_fields(fields);
1330                 if (nb_fields < 0) {
1331                         ret = LTTNG_ERR_UST_LIST_FAIL;
1332                         goto error;
1333                 }
1334                 break;
1335         case LTTNG_DOMAIN_KERNEL:
1336         default:        /* fall-through */
1337                 ret = LTTNG_ERR_UND;
1338                 goto error;
1339         }
1340
1341         return nb_fields;
1342
1343 error:
1344         /* Return negative value to differentiate return code */
1345         return -ret;
1346 }
1347
1348 /*
1349  * Command LTTNG_START_TRACE processed by the client thread.
1350  */
1351 int cmd_start_trace(struct ltt_session *session)
1352 {
1353         int ret;
1354         struct ltt_kernel_session *ksession;
1355         struct ltt_ust_session *usess;
1356         struct ltt_kernel_channel *kchan;
1357
1358         assert(session);
1359
1360         /* Ease our life a bit ;) */
1361         ksession = session->kernel_session;
1362         usess = session->ust_session;
1363
1364         if (session->enabled) {
1365                 /* Already started. */
1366                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
1367                 goto error;
1368         }
1369
1370         session->enabled = 1;
1371
1372         ret = setup_relayd(session);
1373         if (ret != LTTNG_OK) {
1374                 ERR("Error setting up relayd for session %s", session->name);
1375                 goto error;
1376         }
1377
1378         /* Kernel tracing */
1379         if (ksession != NULL) {
1380                 /* Open kernel metadata */
1381                 if (ksession->metadata == NULL) {
1382                         ret = kernel_open_metadata(ksession);
1383                         if (ret < 0) {
1384                                 ret = LTTNG_ERR_KERN_META_FAIL;
1385                                 goto error;
1386                         }
1387                 }
1388
1389                 /* Open kernel metadata stream */
1390                 if (ksession->metadata_stream_fd < 0) {
1391                         ret = kernel_open_metadata_stream(ksession);
1392                         if (ret < 0) {
1393                                 ERR("Kernel create metadata stream failed");
1394                                 ret = LTTNG_ERR_KERN_STREAM_FAIL;
1395                                 goto error;
1396                         }
1397                 }
1398
1399                 /* For each channel */
1400                 cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
1401                         if (kchan->stream_count == 0) {
1402                                 ret = kernel_open_channel_stream(kchan);
1403                                 if (ret < 0) {
1404                                         ret = LTTNG_ERR_KERN_STREAM_FAIL;
1405                                         goto error;
1406                                 }
1407                                 /* Update the stream global counter */
1408                                 ksession->stream_count_global += ret;
1409                         }
1410                 }
1411
1412                 /* Setup kernel consumer socket and send fds to it */
1413                 ret = init_kernel_tracing(ksession);
1414                 if (ret < 0) {
1415                         ret = LTTNG_ERR_KERN_START_FAIL;
1416                         goto error;
1417                 }
1418
1419                 /* This start the kernel tracing */
1420                 ret = kernel_start_session(ksession);
1421                 if (ret < 0) {
1422                         ret = LTTNG_ERR_KERN_START_FAIL;
1423                         goto error;
1424                 }
1425
1426                 /* Quiescent wait after starting trace */
1427                 kernel_wait_quiescent(kernel_tracer_fd);
1428         }
1429
1430         /* Flag session that trace should start automatically */
1431         if (usess) {
1432                 usess->start_trace = 1;
1433
1434                 ret = ust_app_start_trace_all(usess);
1435                 if (ret < 0) {
1436                         ret = LTTNG_ERR_UST_START_FAIL;
1437                         goto error;
1438                 }
1439         }
1440
1441         ret = LTTNG_OK;
1442
1443 error:
1444         return ret;
1445 }
1446
1447 /*
1448  * Command LTTNG_STOP_TRACE processed by the client thread.
1449  */
1450 int cmd_stop_trace(struct ltt_session *session)
1451 {
1452         int ret;
1453         struct ltt_kernel_channel *kchan;
1454         struct ltt_kernel_session *ksession;
1455         struct ltt_ust_session *usess;
1456
1457         assert(session);
1458
1459         /* Short cut */
1460         ksession = session->kernel_session;
1461         usess = session->ust_session;
1462
1463         if (!session->enabled) {
1464                 ret = LTTNG_ERR_TRACE_ALREADY_STOPPED;
1465                 goto error;
1466         }
1467
1468         session->enabled = 0;
1469
1470         /* Kernel tracer */
1471         if (ksession) {
1472                 DBG("Stop kernel tracing");
1473
1474                 /* Flush metadata if exist */
1475                 if (ksession->metadata_stream_fd >= 0) {
1476                         ret = kernel_metadata_flush_buffer(ksession->metadata_stream_fd);
1477                         if (ret < 0) {
1478                                 ERR("Kernel metadata flush failed");
1479                         }
1480                 }
1481
1482                 /* Flush all buffers before stopping */
1483                 cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
1484                         ret = kernel_flush_buffer(kchan);
1485                         if (ret < 0) {
1486                                 ERR("Kernel flush buffer error");
1487                         }
1488                 }
1489
1490                 ret = kernel_stop_session(ksession);
1491                 if (ret < 0) {
1492                         ret = LTTNG_ERR_KERN_STOP_FAIL;
1493                         goto error;
1494                 }
1495
1496                 kernel_wait_quiescent(kernel_tracer_fd);
1497         }
1498
1499         if (usess) {
1500                 usess->start_trace = 0;
1501
1502                 ret = ust_app_stop_trace_all(usess);
1503                 if (ret < 0) {
1504                         ret = LTTNG_ERR_UST_STOP_FAIL;
1505                         goto error;
1506                 }
1507         }
1508
1509         ret = LTTNG_OK;
1510
1511 error:
1512         return ret;
1513 }
1514
1515 /*
1516  * Command LTTNG_SET_CONSUMER_URI processed by the client thread.
1517  */
1518 int cmd_set_consumer_uri(int domain, struct ltt_session *session,
1519                 size_t nb_uri, struct lttng_uri *uris)
1520 {
1521         int ret, i;
1522         struct ltt_kernel_session *ksess = session->kernel_session;
1523         struct ltt_ust_session *usess = session->ust_session;
1524         struct consumer_output *consumer = NULL;
1525
1526         assert(session);
1527         assert(uris);
1528         assert(nb_uri > 0);
1529
1530         /* Can't enable consumer after session started. */
1531         if (session->enabled) {
1532                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
1533                 goto error;
1534         }
1535
1536         if (!session->start_consumer) {
1537                 ret = LTTNG_ERR_NO_CONSUMER;
1538                 goto error;
1539         }
1540
1541         /*
1542          * This case switch makes sure the domain session has a temporary consumer
1543          * so the URL can be set.
1544          */
1545         switch (domain) {
1546         case 0:
1547                 /* Code flow error. A session MUST always have a consumer object */
1548                 assert(session->consumer);
1549                 /*
1550                  * The URL will be added to the tracing session consumer instead of a
1551                  * specific domain consumer.
1552                  */
1553                 consumer = session->consumer;
1554                 break;
1555         case LTTNG_DOMAIN_KERNEL:
1556                 /* Code flow error if we don't have a kernel session here. */
1557                 assert(ksess);
1558
1559                 /* Create consumer output if none exists */
1560                 consumer = ksess->tmp_consumer;
1561                 if (consumer == NULL) {
1562                         consumer = consumer_copy_output(ksess->consumer);
1563                         if (consumer == NULL) {
1564                                 ret = LTTNG_ERR_FATAL;
1565                                 goto error;
1566                         }
1567                         /* Trash the consumer subdir, we are about to set a new one. */
1568                         memset(consumer->subdir, 0, sizeof(consumer->subdir));
1569                         ksess->tmp_consumer = consumer;
1570                 }
1571
1572                 break;
1573         case LTTNG_DOMAIN_UST:
1574                 /* Code flow error if we don't have a kernel session here. */
1575                 assert(usess);
1576
1577                 /* Create consumer output if none exists */
1578                 consumer = usess->tmp_consumer;
1579                 if (consumer == NULL) {
1580                         consumer = consumer_copy_output(usess->consumer);
1581                         if (consumer == NULL) {
1582                                 ret = LTTNG_ERR_FATAL;
1583                                 goto error;
1584                         }
1585                         /* Trash the consumer subdir, we are about to set a new one. */
1586                         memset(consumer->subdir, 0, sizeof(consumer->subdir));
1587                         usess->tmp_consumer = consumer;
1588                 }
1589
1590                 break;
1591         }
1592
1593         for (i = 0; i < nb_uri; i++) {
1594                 struct consumer_socket *socket;
1595                 struct lttng_ht_iter iter;
1596
1597                 ret = add_uri_to_consumer(consumer, &uris[i], domain, session->name);
1598                 if (ret < 0) {
1599                         goto error;
1600                 }
1601
1602                 /*
1603                  * Don't send relayd socket if URI is NOT remote or if the relayd
1604                  * sockets for the session are already sent.
1605                  */
1606                 if (uris[i].dtype == LTTNG_DST_PATH ||
1607                                 consumer->dst.net.relayd_socks_sent) {
1608                         continue;
1609                 }
1610
1611                 /* Try to send relayd URI to the consumer if exist. */
1612                 rcu_read_lock();
1613                 cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter,
1614                                 socket, node.node) {
1615
1616                         /* A socket in the HT should never have a negative fd */
1617                         assert(socket->fd >= 0);
1618
1619                         pthread_mutex_lock(socket->lock);
1620                         ret = send_consumer_relayd_socket(domain, session, &uris[i],
1621                                         consumer, socket->fd);
1622                         pthread_mutex_unlock(socket->lock);
1623                         if (ret != LTTNG_OK) {
1624                                 rcu_read_unlock();
1625                                 goto error;
1626                         }
1627                 }
1628                 rcu_read_unlock();
1629         }
1630
1631         /* All good! */
1632         ret = LTTNG_OK;
1633
1634 error:
1635         return ret;
1636 }
1637
1638 /*
1639  * Command LTTNG_CREATE_SESSION processed by the client thread.
1640  */
1641 int cmd_create_session_uri(char *name, struct lttng_uri *uris,
1642                 size_t nb_uri, lttng_sock_cred *creds)
1643 {
1644         int ret;
1645         char *path = NULL;
1646         struct ltt_session *session;
1647
1648         assert(name);
1649
1650         /*
1651          * Verify if the session already exist
1652          *
1653          * XXX: There is no need for the session lock list here since the caller
1654          * (process_client_msg) is holding it. We might want to change that so a
1655          * single command does not lock the entire session list.
1656          */
1657         session = session_find_by_name(name);
1658         if (session != NULL) {
1659                 ret = LTTNG_ERR_EXIST_SESS;
1660                 goto find_error;
1661         }
1662
1663         /* Create tracing session in the registry */
1664         ret = session_create(name, path, LTTNG_SOCK_GET_UID_CRED(creds),
1665                         LTTNG_SOCK_GET_GID_CRED(creds));
1666         if (ret != LTTNG_OK) {
1667                 goto session_error;
1668         }
1669
1670         /*
1671          * Get the newly created session pointer back
1672          *
1673          * XXX: There is no need for the session lock list here since the caller
1674          * (process_client_msg) is holding it. We might want to change that so a
1675          * single command does not lock the entire session list.
1676          */
1677         session = session_find_by_name(name);
1678         assert(session);
1679
1680         /* Create default consumer output for the session not yet created. */
1681         session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
1682         if (session->consumer == NULL) {
1683                 ret = LTTNG_ERR_FATAL;
1684                 goto consumer_error;
1685         }
1686
1687         /*
1688          * This means that the lttng_create_session call was called with the _path_
1689          * argument set to NULL.
1690          */
1691         if (uris == NULL) {
1692                 /*
1693                  * At this point, we'll skip the consumer URI setup and create a
1694                  * session with a NULL path which will flag the session to NOT spawn a
1695                  * consumer.
1696                  */
1697                 DBG("Create session %s with NO uri, skipping consumer setup", name);
1698                 goto end;
1699         }
1700
1701         session->start_consumer = 1;
1702
1703         ret = cmd_set_consumer_uri(0, session, nb_uri, uris);
1704         if (ret != LTTNG_OK) {
1705                 goto consumer_error;
1706         }
1707
1708         session->consumer->enabled = 1;
1709
1710 end:
1711         return LTTNG_OK;
1712
1713 consumer_error:
1714         session_destroy(session);
1715 session_error:
1716 find_error:
1717         return ret;
1718 }
1719
1720 /*
1721  * Command LTTNG_DESTROY_SESSION processed by the client thread.
1722  */
1723 int cmd_destroy_session(struct ltt_session *session, int wpipe)
1724 {
1725         int ret;
1726         struct ltt_ust_session *usess;
1727         struct ltt_kernel_session *ksess;
1728
1729         /* Safety net */
1730         assert(session);
1731
1732         usess = session->ust_session;
1733         ksess = session->kernel_session;
1734
1735         /* Clean kernel session teardown */
1736         kernel_destroy_session(ksess);
1737
1738         /* UST session teardown */
1739         if (usess) {
1740                 /* Close any relayd session */
1741                 consumer_output_send_destroy_relayd(usess->consumer);
1742
1743                 /* Destroy every UST application related to this session. */
1744                 ret = ust_app_destroy_trace_all(usess);
1745                 if (ret) {
1746                         ERR("Error in ust_app_destroy_trace_all");
1747                 }
1748
1749                 /* Clean up the rest. */
1750                 trace_ust_destroy_session(usess);
1751         }
1752
1753         /*
1754          * Must notify the kernel thread here to update it's poll set in order to
1755          * remove the channel(s)' fd just destroyed.
1756          */
1757         ret = notify_thread_pipe(wpipe);
1758         if (ret < 0) {
1759                 PERROR("write kernel poll pipe");
1760         }
1761
1762         ret = session_destroy(session);
1763
1764         return ret;
1765 }
1766
1767 /*
1768  * Command LTTNG_CALIBRATE processed by the client thread.
1769  */
1770 int cmd_calibrate(int domain, struct lttng_calibrate *calibrate)
1771 {
1772         int ret;
1773
1774         switch (domain) {
1775         case LTTNG_DOMAIN_KERNEL:
1776         {
1777                 struct lttng_kernel_calibrate kcalibrate;
1778
1779                 kcalibrate.type = calibrate->type;
1780                 ret = kernel_calibrate(kernel_tracer_fd, &kcalibrate);
1781                 if (ret < 0) {
1782                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1783                         goto error;
1784                 }
1785                 break;
1786         }
1787         case LTTNG_DOMAIN_UST:
1788         {
1789                 struct lttng_ust_calibrate ucalibrate;
1790
1791                 ucalibrate.type = calibrate->type;
1792                 ret = ust_app_calibrate_glb(&ucalibrate);
1793                 if (ret < 0) {
1794                         ret = LTTNG_ERR_UST_CALIBRATE_FAIL;
1795                         goto error;
1796                 }
1797                 break;
1798         }
1799         default:
1800                 ret = LTTNG_ERR_UND;
1801                 goto error;
1802         }
1803
1804         ret = LTTNG_OK;
1805
1806 error:
1807         return ret;
1808 }
1809
1810 /*
1811  * Command LTTNG_REGISTER_CONSUMER processed by the client thread.
1812  */
1813 int cmd_register_consumer(struct ltt_session *session, int domain,
1814                 const char *sock_path, struct consumer_data *cdata)
1815 {
1816         int ret, sock;
1817         struct consumer_socket *socket;
1818
1819         assert(session);
1820         assert(cdata);
1821         assert(sock_path);
1822
1823         switch (domain) {
1824         case LTTNG_DOMAIN_KERNEL:
1825         {
1826                 struct ltt_kernel_session *ksess = session->kernel_session;
1827
1828                 assert(ksess);
1829
1830                 /* Can't register a consumer if there is already one */
1831                 if (ksess->consumer_fds_sent != 0) {
1832                         ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
1833                         goto error;
1834                 }
1835
1836                 sock = lttcomm_connect_unix_sock(sock_path);
1837                 if (sock < 0) {
1838                         ret = LTTNG_ERR_CONNECT_FAIL;
1839                         goto error;
1840                 }
1841
1842                 socket = consumer_allocate_socket(sock);
1843                 if (socket == NULL) {
1844                         ret = LTTNG_ERR_FATAL;
1845                         close(sock);
1846                         goto error;
1847                 }
1848
1849                 socket->lock = zmalloc(sizeof(pthread_mutex_t));
1850                 if (socket->lock == NULL) {
1851                         PERROR("zmalloc pthread mutex");
1852                         ret = LTTNG_ERR_FATAL;
1853                         goto error;
1854                 }
1855                 pthread_mutex_init(socket->lock, NULL);
1856                 socket->registered = 1;
1857
1858                 rcu_read_lock();
1859                 consumer_add_socket(socket, ksess->consumer);
1860                 rcu_read_unlock();
1861
1862                 pthread_mutex_lock(&cdata->pid_mutex);
1863                 cdata->pid = -1;
1864                 pthread_mutex_unlock(&cdata->pid_mutex);
1865
1866                 break;
1867         }
1868         default:
1869                 /* TODO: Userspace tracing */
1870                 ret = LTTNG_ERR_UND;
1871                 goto error;
1872         }
1873
1874         ret = LTTNG_OK;
1875
1876 error:
1877         return ret;
1878 }
1879
1880 /*
1881  * Command LTTNG_LIST_DOMAINS processed by the client thread.
1882  */
1883 ssize_t cmd_list_domains(struct ltt_session *session,
1884                 struct lttng_domain **domains)
1885 {
1886         int ret, index = 0;
1887         ssize_t nb_dom = 0;
1888
1889         if (session->kernel_session != NULL) {
1890                 DBG3("Listing domains found kernel domain");
1891                 nb_dom++;
1892         }
1893
1894         if (session->ust_session != NULL) {
1895                 DBG3("Listing domains found UST global domain");
1896                 nb_dom++;
1897         }
1898
1899         *domains = zmalloc(nb_dom * sizeof(struct lttng_domain));
1900         if (*domains == NULL) {
1901                 ret = LTTNG_ERR_FATAL;
1902                 goto error;
1903         }
1904
1905         if (session->kernel_session != NULL) {
1906                 (*domains)[index].type = LTTNG_DOMAIN_KERNEL;
1907                 index++;
1908         }
1909
1910         if (session->ust_session != NULL) {
1911                 (*domains)[index].type = LTTNG_DOMAIN_UST;
1912                 index++;
1913         }
1914
1915         return nb_dom;
1916
1917 error:
1918         /* Return negative value to differentiate return code */
1919         return -ret;
1920 }
1921
1922
1923 /*
1924  * Command LTTNG_LIST_CHANNELS processed by the client thread.
1925  */
1926 ssize_t cmd_list_channels(int domain, struct ltt_session *session,
1927                 struct lttng_channel **channels)
1928 {
1929         int ret;
1930         ssize_t nb_chan = 0;
1931
1932         switch (domain) {
1933         case LTTNG_DOMAIN_KERNEL:
1934                 if (session->kernel_session != NULL) {
1935                         nb_chan = session->kernel_session->channel_count;
1936                 }
1937                 DBG3("Number of kernel channels %zd", nb_chan);
1938                 if (nb_chan <= 0) {
1939                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
1940                 }
1941                 break;
1942         case LTTNG_DOMAIN_UST:
1943                 if (session->ust_session != NULL) {
1944                         nb_chan = lttng_ht_get_count(
1945                                         session->ust_session->domain_global.channels);
1946                 }
1947                 DBG3("Number of UST global channels %zd", nb_chan);
1948                 if (nb_chan <= 0) {
1949                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1950                 }
1951                 break;
1952         default:
1953                 *channels = NULL;
1954                 ret = LTTNG_ERR_UND;
1955                 goto error;
1956         }
1957
1958         if (nb_chan > 0) {
1959                 *channels = zmalloc(nb_chan * sizeof(struct lttng_channel));
1960                 if (*channels == NULL) {
1961                         ret = LTTNG_ERR_FATAL;
1962                         goto error;
1963                 }
1964
1965                 list_lttng_channels(domain, session, *channels);
1966         } else {
1967                 *channels = NULL;
1968                 /* Ret value was set in the domain switch case */
1969                 goto error;
1970         }
1971
1972         return nb_chan;
1973
1974 error:
1975         /* Return negative value to differentiate return code */
1976         return -ret;
1977 }
1978
1979 /*
1980  * Command LTTNG_LIST_EVENTS processed by the client thread.
1981  */
1982 ssize_t cmd_list_events(int domain, struct ltt_session *session,
1983                 char *channel_name, struct lttng_event **events)
1984 {
1985         int ret = 0;
1986         ssize_t nb_event = 0;
1987
1988         switch (domain) {
1989         case LTTNG_DOMAIN_KERNEL:
1990                 if (session->kernel_session != NULL) {
1991                         nb_event = list_lttng_kernel_events(channel_name,
1992                                         session->kernel_session, events);
1993                 }
1994                 break;
1995         case LTTNG_DOMAIN_UST:
1996         {
1997                 if (session->ust_session != NULL) {
1998                         nb_event = list_lttng_ust_global_events(channel_name,
1999                                         &session->ust_session->domain_global, events);
2000                 }
2001                 break;
2002         }
2003         default:
2004                 ret = LTTNG_ERR_UND;
2005                 goto error;
2006         }
2007
2008         return nb_event;
2009
2010 error:
2011         /* Return negative value to differentiate return code */
2012         return -ret;
2013 }
2014
2015 /*
2016  * Using the session list, filled a lttng_session array to send back to the
2017  * client for session listing.
2018  *
2019  * The session list lock MUST be acquired before calling this function. Use
2020  * session_lock_list() and session_unlock_list().
2021  */
2022 void cmd_list_lttng_sessions(struct lttng_session *sessions, uid_t uid,
2023                 gid_t gid)
2024 {
2025         int ret;
2026         unsigned int i = 0;
2027         struct ltt_session *session;
2028         struct ltt_session_list *list = session_get_list();
2029
2030         DBG("Getting all available session for UID %d GID %d",
2031                         uid, gid);
2032         /*
2033          * Iterate over session list and append data after the control struct in
2034          * the buffer.
2035          */
2036         cds_list_for_each_entry(session, &list->head, list) {
2037                 /*
2038                  * Only list the sessions the user can control.
2039                  */
2040                 if (!session_access_ok(session, uid, gid)) {
2041                         continue;
2042                 }
2043
2044                 struct ltt_kernel_session *ksess = session->kernel_session;
2045                 struct ltt_ust_session *usess = session->ust_session;
2046
2047                 if (session->consumer->type == CONSUMER_DST_NET ||
2048                                 (ksess && ksess->consumer->type == CONSUMER_DST_NET) ||
2049                                 (usess && usess->consumer->type == CONSUMER_DST_NET)) {
2050                         ret = build_network_session_path(sessions[i].path,
2051                                         sizeof(session[i].path), session);
2052                 } else {
2053                         ret = snprintf(sessions[i].path, sizeof(session[i].path), "%s",
2054                                         session->consumer->dst.trace_path);
2055                 }
2056                 if (ret < 0) {
2057                         PERROR("snprintf session path");
2058                         continue;
2059                 }
2060
2061                 strncpy(sessions[i].name, session->name, NAME_MAX);
2062                 sessions[i].name[NAME_MAX - 1] = '\0';
2063                 sessions[i].enabled = session->enabled;
2064                 i++;
2065         }
2066 }
2067
2068 /*
2069  * Command LTTNG_DISABLE_CONSUMER processed by the client thread.
2070  */
2071 int cmd_disable_consumer(int domain, struct ltt_session *session)
2072 {
2073         int ret;
2074         struct ltt_kernel_session *ksess = session->kernel_session;
2075         struct ltt_ust_session *usess = session->ust_session;
2076         struct consumer_output *consumer;
2077
2078         assert(session);
2079
2080         if (session->enabled) {
2081                 /* Can't disable consumer on an already started session */
2082                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2083                 goto error;
2084         }
2085
2086         if (!session->start_consumer) {
2087                 ret = LTTNG_ERR_NO_CONSUMER;
2088                 goto error;
2089         }
2090
2091         switch (domain) {
2092         case 0:
2093                 DBG("Disable tracing session %s consumer", session->name);
2094                 consumer = session->consumer;
2095                 break;
2096         case LTTNG_DOMAIN_KERNEL:
2097                 /* Code flow error if we don't have a kernel session here. */
2098                 assert(ksess);
2099
2100                 DBG("Disabling kernel consumer");
2101                 consumer = ksess->consumer;
2102
2103                 break;
2104         case LTTNG_DOMAIN_UST:
2105                 /* Code flow error if we don't have a UST session here. */
2106                 assert(usess);
2107
2108                 DBG("Disabling UST consumer");
2109                 consumer = usess->consumer;
2110
2111                 break;
2112         default:
2113                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
2114                 goto error;
2115         }
2116
2117         if (consumer) {
2118                 consumer->enabled = 0;
2119                 /* Success at this point */
2120                 ret = LTTNG_OK;
2121         } else {
2122                 ret = LTTNG_ERR_NO_CONSUMER;
2123         }
2124
2125 error:
2126         return ret;
2127 }
2128
2129 /*
2130  * Command LTTNG_ENABLE_CONSUMER processed by the client thread.
2131  */
2132 int cmd_enable_consumer(int domain, struct ltt_session *session)
2133 {
2134         int ret;
2135         struct ltt_kernel_session *ksess = session->kernel_session;
2136         struct ltt_ust_session *usess = session->ust_session;
2137         struct consumer_output *consumer = NULL;
2138
2139         assert(session);
2140
2141         /* Can't enable consumer after session started. */
2142         if (session->enabled) {
2143                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2144                 goto error;
2145         }
2146
2147         if (!session->start_consumer) {
2148                 ret = LTTNG_ERR_NO_CONSUMER;
2149                 goto error;
2150         }
2151
2152         switch (domain) {
2153         case 0:
2154                 assert(session->consumer);
2155                 consumer = session->consumer;
2156                 break;
2157         case LTTNG_DOMAIN_KERNEL:
2158                 /* Code flow error if we don't have a kernel session here. */
2159                 assert(ksess);
2160
2161                 /*
2162                  * Check if we have already sent fds to the consumer. In that case,
2163                  * the enable-consumer command can't be used because a start trace
2164                  * had previously occured.
2165                  */
2166                 if (ksess->consumer_fds_sent) {
2167                         ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2168                         goto error;
2169                 }
2170
2171                 consumer = ksess->tmp_consumer;
2172                 if (consumer == NULL) {
2173                         ret = LTTNG_OK;
2174                         /* No temp. consumer output exists. Using the current one. */
2175                         DBG3("No temporary consumer. Using default");
2176                         consumer = ksess->consumer;
2177                         goto error;
2178                 }
2179
2180                 switch (consumer->type) {
2181                 case CONSUMER_DST_LOCAL:
2182                         DBG2("Consumer output is local. Creating directory(ies)");
2183
2184                         /* Create directory(ies) */
2185                         ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2186                                         S_IRWXU | S_IRWXG, session->uid, session->gid);
2187                         if (ret < 0) {
2188                                 if (ret != -EEXIST) {
2189                                         ERR("Trace directory creation error");
2190                                         ret = LTTNG_ERR_FATAL;
2191                                         goto error;
2192                                 }
2193                         }
2194                         break;
2195                 case CONSUMER_DST_NET:
2196                         DBG2("Consumer output is network. Validating URIs");
2197                         /* Validate if we have both control and data path set. */
2198                         if (!consumer->dst.net.control_isset) {
2199                                 ret = LTTNG_ERR_URL_CTRL_MISS;
2200                                 goto error;
2201                         }
2202
2203                         if (!consumer->dst.net.data_isset) {
2204                                 ret = LTTNG_ERR_URL_DATA_MISS;
2205                                 goto error;
2206                         }
2207
2208                         /* Check established network session state */
2209                         if (session->net_handle == 0) {
2210                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2211                                 ERR("Session network handle is not set on enable-consumer");
2212                                 goto error;
2213                         }
2214
2215                         break;
2216                 }
2217
2218                 /* Append default kernel trace dir to subdir */
2219                 strncat(ksess->consumer->subdir, DEFAULT_KERNEL_TRACE_DIR,
2220                                 sizeof(ksess->consumer->subdir) -
2221                                 strlen(ksess->consumer->subdir) - 1);
2222
2223                 /*
2224                  * @session-lock
2225                  * This is race free for now since the session lock is acquired before
2226                  * ending up in this function. No other threads can access this kernel
2227                  * session without this lock hence freeing the consumer output object
2228                  * is valid.
2229                  */
2230                 rcu_read_lock();
2231                 consumer_destroy_output(ksess->consumer);
2232                 rcu_read_unlock();
2233                 ksess->consumer = consumer;
2234                 ksess->tmp_consumer = NULL;
2235
2236                 break;
2237         case LTTNG_DOMAIN_UST:
2238                 /* Code flow error if we don't have a UST session here. */
2239                 assert(usess);
2240
2241                 /*
2242                  * Check if we have already sent fds to the consumer. In that case,
2243                  * the enable-consumer command can't be used because a start trace
2244                  * had previously occured.
2245                  */
2246                 if (usess->start_trace) {
2247                         ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2248                         goto error;
2249                 }
2250
2251                 consumer = usess->tmp_consumer;
2252                 if (consumer == NULL) {
2253                         ret = LTTNG_OK;
2254                         /* No temp. consumer output exists. Using the current one. */
2255                         DBG3("No temporary consumer. Using default");
2256                         consumer = usess->consumer;
2257                         goto error;
2258                 }
2259
2260                 switch (consumer->type) {
2261                 case CONSUMER_DST_LOCAL:
2262                         DBG2("Consumer output is local. Creating directory(ies)");
2263
2264                         /* Create directory(ies) */
2265                         ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2266                                         S_IRWXU | S_IRWXG, session->uid, session->gid);
2267                         if (ret < 0) {
2268                                 if (ret != -EEXIST) {
2269                                         ERR("Trace directory creation error");
2270                                         ret = LTTNG_ERR_FATAL;
2271                                         goto error;
2272                                 }
2273                         }
2274                         break;
2275                 case CONSUMER_DST_NET:
2276                         DBG2("Consumer output is network. Validating URIs");
2277                         /* Validate if we have both control and data path set. */
2278                         if (!consumer->dst.net.control_isset) {
2279                                 ret = LTTNG_ERR_URL_CTRL_MISS;
2280                                 goto error;
2281                         }
2282
2283                         if (!consumer->dst.net.data_isset) {
2284                                 ret = LTTNG_ERR_URL_DATA_MISS;
2285                                 goto error;
2286                         }
2287
2288                         /* Check established network session state */
2289                         if (session->net_handle == 0) {
2290                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2291                                 DBG2("Session network handle is not set on enable-consumer");
2292                                 goto error;
2293                         }
2294
2295                         if (consumer->net_seq_index == -1) {
2296                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2297                                 DBG2("Network index is not set on the consumer");
2298                                 goto error;
2299                         }
2300
2301                         break;
2302                 }
2303
2304                 /* Append default kernel trace dir to subdir */
2305                 strncat(usess->consumer->subdir, DEFAULT_UST_TRACE_DIR,
2306                                 sizeof(usess->consumer->subdir) -
2307                                 strlen(usess->consumer->subdir) - 1);
2308
2309                 /*
2310                  * @session-lock
2311                  * This is race free for now since the session lock is acquired before
2312                  * ending up in this function. No other threads can access this kernel
2313                  * session without this lock hence freeing the consumer output object
2314                  * is valid.
2315                  */
2316                 rcu_read_lock();
2317                 consumer_destroy_output(usess->consumer);
2318                 rcu_read_unlock();
2319                 usess->consumer = consumer;
2320                 usess->tmp_consumer = NULL;
2321
2322                 break;
2323         }
2324
2325         /* Enable it */
2326         if (consumer) {
2327                 consumer->enabled = 1;
2328                 /* Success at this point */
2329                 ret = LTTNG_OK;
2330         } else {
2331                 /* Should not really happend... */
2332                 ret = LTTNG_ERR_NO_CONSUMER;
2333         }
2334
2335 error:
2336         return ret;
2337 }
2338
2339 /*
2340  * Init command subsystem.
2341  */
2342 void cmd_init(void)
2343 {
2344         /*
2345          * Set network sequence index to 1 for streams to match a relayd socket on
2346          * the consumer side.
2347          */
2348         uatomic_set(&relayd_net_seq_idx, 1);
2349
2350         DBG("Command subsystem initialized");
2351 }