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         /*
 105          * Do we have a UST url set. If yes, this means we have both kernel and UST
 106          * to print.
 107          */
 108         if (strlen(tmp_uurl) > 0) {
 109                 ret = snprintf(dst, size, "[K]: %s [data: %d] -- [U]: %s [data: %d]",
 110                                 tmp_urls, kdata_port, tmp_uurl, udata_port);
 111         } else {
 112                 int dport;
 113                 if (kuri) {
 114                         dport = kdata_port;
 115                 } else {
 116                         /* No kernel URI, use the UST port. */
 117                         dport = udata_port;
 118                 }
 119                 ret = snprintf(dst, size, "%s [data: %d]", tmp_urls, dport);
 120         }
 121
 122 error:
 123         return ret;
 124 }
 125
 126 /*
 127  * Fill lttng_channel array of all channels.
 128  */
 129 static void list_lttng_channels(int domain, struct ltt_session *session,
 130                 struct lttng_channel *channels)
 131 {
 132         int i = 0;
 133         struct ltt_kernel_channel *kchan;
 134
 135         DBG("Listing channels for session %s", session->name);
 136
 137         switch (domain) {
 138         case LTTNG_DOMAIN_KERNEL:
 139                 /* Kernel channels */
 140                 if (session->kernel_session != NULL) {
 141                         cds_list_for_each_entry(kchan,
 142                                         &session->kernel_session->channel_list.head, list) {
 143                                 /* Copy lttng_channel struct to array */
 144                                 memcpy(&channels[i], kchan->channel, sizeof(struct lttng_channel));
 145                                 channels[i].enabled = kchan->enabled;
 146                                 i++;
 147                         }
 148                 }
 149                 break;
 150         case LTTNG_DOMAIN_UST:
 151         {
 152                 struct lttng_ht_iter iter;
 153                 struct ltt_ust_channel *uchan;
 154
 155                 rcu_read_lock();
 156                 cds_lfht_for_each_entry(session->ust_session->domain_global.channels->ht,
 157                                 &iter.iter, uchan, node.node) {
 158                         strncpy(channels[i].name, uchan->name, LTTNG_SYMBOL_NAME_LEN);
 159                         channels[i].attr.overwrite = uchan->attr.overwrite;
 160                         channels[i].attr.subbuf_size = uchan->attr.subbuf_size;
 161                         channels[i].attr.num_subbuf = uchan->attr.num_subbuf;
 162                         channels[i].attr.switch_timer_interval =
 163                                 uchan->attr.switch_timer_interval;
 164                         channels[i].attr.read_timer_interval =
 165                                 uchan->attr.read_timer_interval;
 166                         channels[i].enabled = uchan->enabled;
 167                         switch (uchan->attr.output) {
 168                         case LTTNG_UST_MMAP:
 169                         default:
 170                                 channels[i].attr.output = LTTNG_EVENT_MMAP;
 171                                 break;
 172                         }
 173                         i++;
 174                 }
 175                 rcu_read_unlock();
 176                 break;
 177         }
 178         default:
 179                 break;
 180         }
 181 }
 182
 183 /*
 184  * Create a list of ust global domain events.
 185  */
 186 static int list_lttng_ust_global_events(char *channel_name,
 187                 struct ltt_ust_domain_global *ust_global, struct lttng_event **events)
 188 {
 189         int i = 0, ret = 0;
 190         unsigned int nb_event = 0;
 191         struct lttng_ht_iter iter;
 192         struct lttng_ht_node_str *node;
 193         struct ltt_ust_channel *uchan;
 194         struct ltt_ust_event *uevent;
 195         struct lttng_event *tmp;
 196
 197         DBG("Listing UST global events for channel %s", channel_name);
 198
 199         rcu_read_lock();
 200
 201         lttng_ht_lookup(ust_global->channels, (void *)channel_name, &iter);
 202         node = lttng_ht_iter_get_node_str(&iter);
 203         if (node == NULL) {
 204                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 205                 goto error;
 206         }
 207
 208         uchan = caa_container_of(&node->node, struct ltt_ust_channel, node.node);
 209
 210         nb_event += lttng_ht_get_count(uchan->events);
 211
 212         if (nb_event == 0) {
 213                 ret = nb_event;
 214                 goto error;
 215         }
 216
 217         DBG3("Listing UST global %d events", nb_event);
 218
 219         tmp = zmalloc(nb_event * sizeof(struct lttng_event));
 220         if (tmp == NULL) {
 221                 ret = LTTNG_ERR_FATAL;
 222                 goto error;
 223         }
 224
 225         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent, node.node) {
 226                 strncpy(tmp[i].name, uevent->attr.name, LTTNG_SYMBOL_NAME_LEN);
 227                 tmp[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 228                 tmp[i].enabled = uevent->enabled;
 229
 230                 switch (uevent->attr.instrumentation) {
 231                 case LTTNG_UST_TRACEPOINT:
 232                         tmp[i].type = LTTNG_EVENT_TRACEPOINT;
 233                         break;
 234                 case LTTNG_UST_PROBE:
 235                         tmp[i].type = LTTNG_EVENT_PROBE;
 236                         break;
 237                 case LTTNG_UST_FUNCTION:
 238                         tmp[i].type = LTTNG_EVENT_FUNCTION;
 239                         break;
 240                 }
 241
 242                 tmp[i].loglevel = uevent->attr.loglevel;
 243                 switch (uevent->attr.loglevel_type) {
 244                 case LTTNG_UST_LOGLEVEL_ALL:
 245                         tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
 246                         break;
 247                 case LTTNG_UST_LOGLEVEL_RANGE:
 248                         tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
 249                         break;
 250                 case LTTNG_UST_LOGLEVEL_SINGLE:
 251                         tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
 252                         break;
 253                 }
 254                 if (uevent->filter) {
 255                         tmp[i].filter = 1;
 256                 }
 257                 i++;
 258         }
 259
 260         ret = nb_event;
 261         *events = tmp;
 262
 263 error:
 264         rcu_read_unlock();
 265         return ret;
 266 }
 267
 268 /*
 269  * Fill lttng_event array of all kernel events in the channel.
 270  */
 271 static int list_lttng_kernel_events(char *channel_name,
 272                 struct ltt_kernel_session *kernel_session, struct lttng_event **events)
 273 {
 274         int i = 0, ret;
 275         unsigned int nb_event;
 276         struct ltt_kernel_event *event;
 277         struct ltt_kernel_channel *kchan;
 278
 279         kchan = trace_kernel_get_channel_by_name(channel_name, kernel_session);
 280         if (kchan == NULL) {
 281                 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 282                 goto error;
 283         }
 284
 285         nb_event = kchan->event_count;
 286
 287         DBG("Listing events for channel %s", kchan->channel->name);
 288
 289         if (nb_event == 0) {
 290                 goto end;
 291         }
 292
 293         *events = zmalloc(nb_event * sizeof(struct lttng_event));
 294         if (*events == NULL) {
 295                 ret = LTTNG_ERR_FATAL;
 296                 goto error;
 297         }
 298
 299         /* Kernel channels */
 300         cds_list_for_each_entry(event, &kchan->events_list.head , list) {
 301                 strncpy((*events)[i].name, event->event->name, LTTNG_SYMBOL_NAME_LEN);
 302                 (*events)[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 303                 (*events)[i].enabled = event->enabled;
 304
 305                 switch (event->event->instrumentation) {
 306                 case LTTNG_KERNEL_TRACEPOINT:
 307                         (*events)[i].type = LTTNG_EVENT_TRACEPOINT;
 308                         break;
 309                 case LTTNG_KERNEL_KPROBE:
 310                 case LTTNG_KERNEL_KRETPROBE:
 311                         (*events)[i].type = LTTNG_EVENT_PROBE;
 312                         memcpy(&(*events)[i].attr.probe, &event->event->u.kprobe,
 313                                         sizeof(struct lttng_kernel_kprobe));
 314                         break;
 315                 case LTTNG_KERNEL_FUNCTION:
 316                         (*events)[i].type = LTTNG_EVENT_FUNCTION;
 317                         memcpy(&((*events)[i].attr.ftrace), &event->event->u.ftrace,
 318                                         sizeof(struct lttng_kernel_function));
 319                         break;
 320                 case LTTNG_KERNEL_NOOP:
 321                         (*events)[i].type = LTTNG_EVENT_NOOP;
 322                         break;
 323                 case LTTNG_KERNEL_SYSCALL:
 324                         (*events)[i].type = LTTNG_EVENT_SYSCALL;
 325                         break;
 326                 case LTTNG_KERNEL_ALL:
 327                         assert(0);
 328                         break;
 329                 }
 330                 i++;
 331         }
 332
 333 end:
 334         return nb_event;
 335
 336 error:
 337         /* Negate the error code to differentiate the size from an error */
 338         return -ret;
 339 }
 340
 341 /*
 342  * Add URI so the consumer output object. Set the correct path depending on the
 343  * domain adding the default trace directory.
 344  */
 345 static int add_uri_to_consumer(struct consumer_output *consumer,
 346                 struct lttng_uri *uri, int domain, const char *session_name)
 347 {
 348         int ret = LTTNG_OK;
 349         const char *default_trace_dir;
 350
 351         assert(uri);
 352
 353         if (consumer == NULL) {
 354                 DBG("No consumer detected. Don't add URI. Stopping.");
 355                 ret = LTTNG_ERR_NO_CONSUMER;
 356                 goto error;
 357         }
 358
 359         switch (domain) {
 360         case LTTNG_DOMAIN_KERNEL:
 361                 default_trace_dir = DEFAULT_KERNEL_TRACE_DIR;
 362                 break;
 363         case LTTNG_DOMAIN_UST:
 364                 default_trace_dir = DEFAULT_UST_TRACE_DIR;
 365                 break;
 366         default:
 367                 /*
 368                  * This case is possible is we try to add the URI to the global tracing
 369                  * session consumer object which in this case there is no subdir.
 370                  */
 371                 default_trace_dir = "";
 372         }
 373
 374         switch (uri->dtype) {
 375         case LTTNG_DST_IPV4:
 376         case LTTNG_DST_IPV6:
 377                 DBG2("Setting network URI to consumer");
 378
 379                 /* Set URI into consumer output object */
 380                 ret = consumer_set_network_uri(consumer, uri);
 381                 if (ret < 0) {
 382                         ret = LTTNG_ERR_FATAL;
 383                         goto error;
 384                 } else if (ret == 1) {
 385                         /*
 386                          * URI was the same in the consumer so we do not append the subdir
 387                          * again so to not duplicate output dir.
 388                          */
 389                         goto error;
 390                 }
 391
 392                 if (uri->stype == LTTNG_STREAM_CONTROL && strlen(uri->subdir) == 0) {
 393                         ret = consumer_set_subdir(consumer, session_name);
 394                         if (ret < 0) {
 395                                 ret = LTTNG_ERR_FATAL;
 396                                 goto error;
 397                         }
 398                 }
 399
 400                 if (uri->stype == LTTNG_STREAM_CONTROL) {
 401                         /* On a new subdir, reappend the default trace dir. */
 402                         strncat(consumer->subdir, default_trace_dir,
 403                                         sizeof(consumer->subdir) - strlen(consumer->subdir) - 1);
 404                         DBG3("Append domain trace name to subdir %s", consumer->subdir);
 405                 }
 406
 407                 break;
 408         case LTTNG_DST_PATH:
 409                 DBG2("Setting trace directory path from URI to %s", uri->dst.path);
 410                 memset(consumer->dst.trace_path, 0,
 411                                 sizeof(consumer->dst.trace_path));
 412                 strncpy(consumer->dst.trace_path, uri->dst.path,
 413                                 sizeof(consumer->dst.trace_path));
 414                 /* Append default trace dir */
 415                 strncat(consumer->dst.trace_path, default_trace_dir,
 416                                 sizeof(consumer->dst.trace_path) -
 417                                 strlen(consumer->dst.trace_path) - 1);
 418                 /* Flag consumer as local. */
 419                 consumer->type = CONSUMER_DST_LOCAL;
 420                 break;
 421         }
 422
 423 error:
 424         return ret;
 425 }
 426
 427 /*
 428  * Init tracing by creating trace directory and sending fds kernel consumer.
 429  */
 430 static int init_kernel_tracing(struct ltt_kernel_session *session)
 431 {
 432         int ret = 0;
 433         struct lttng_ht_iter iter;
 434         struct consumer_socket *socket;
 435
 436         assert(session);
 437
 438         rcu_read_lock();
 439
 440         if (session->consumer_fds_sent == 0 && session->consumer != NULL) {
 441                 cds_lfht_for_each_entry(session->consumer->socks->ht, &iter.iter,
 442                                 socket, node.node) {
 443                         /* Code flow error */
 444                         assert(socket->fd >= 0);
 445
 446                         pthread_mutex_lock(socket->lock);
 447                         ret = kernel_consumer_send_session(socket, session);
 448                         pthread_mutex_unlock(socket->lock);
 449                         if (ret < 0) {
 450                                 ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
 451                                 goto error;
 452                         }
 453                 }
 454         }
 455
 456 error:
 457         rcu_read_unlock();
 458         return ret;
 459 }
 460
 461 /*
 462  * Create a socket to the relayd using the URI.
 463  *
 464  * On success, the relayd_sock pointer is set to the created socket.
 465  * Else, it's stays untouched and a lttcomm error code is returned.
 466  */
 467 static int create_connect_relayd(struct consumer_output *output,
 468                 const char *session_name, struct lttng_uri *uri,
 469                 struct lttcomm_sock **relayd_sock)
 470 {
 471         int ret;
 472         struct lttcomm_sock *sock;
 473
 474         /* Create socket object from URI */
 475         sock = lttcomm_alloc_sock_from_uri(uri);
 476         if (sock == NULL) {
 477                 ret = LTTNG_ERR_FATAL;
 478                 goto error;
 479         }
 480
 481         ret = lttcomm_create_sock(sock);
 482         if (ret < 0) {
 483                 ret = LTTNG_ERR_FATAL;
 484                 goto error;
 485         }
 486
 487         /* Connect to relayd so we can proceed with a session creation. */
 488         ret = relayd_connect(sock);
 489         if (ret < 0) {
 490                 ERR("Unable to reach lttng-relayd");
 491                 ret = LTTNG_ERR_RELAYD_CONNECT_FAIL;
 492                 goto free_sock;
 493         }
 494
 495         /* Create socket for control stream. */
 496         if (uri->stype == LTTNG_STREAM_CONTROL) {
 497                 DBG3("Creating relayd stream socket from URI");
 498
 499                 /* Check relayd version */
 500                 ret = relayd_version_check(sock, RELAYD_VERSION_COMM_MAJOR,
 501                                 RELAYD_VERSION_COMM_MINOR);
 502                 if (ret < 0) {
 503                         ret = LTTNG_ERR_RELAYD_VERSION_FAIL;
 504                         goto close_sock;
 505                 }
 506         } else if (uri->stype == LTTNG_STREAM_DATA) {
 507                 DBG3("Creating relayd data socket from URI");
 508         } else {
 509                 /* Command is not valid */
 510                 ERR("Relayd invalid stream type: %d", uri->stype);
 511                 ret = LTTNG_ERR_INVALID;
 512                 goto close_sock;
 513         }
 514
 515         *relayd_sock = sock;
 516
 517         return LTTNG_OK;
 518
 519 close_sock:
 520         if (sock) {
 521                 (void) relayd_close(sock);
 522         }
 523 free_sock:
 524         if (sock) {
 525                 lttcomm_destroy_sock(sock);
 526         }
 527 error:
 528         return ret;
 529 }
 530
 531 /*
 532  * Connect to the relayd using URI and send the socket to the right consumer.
 533  */
 534 static int send_consumer_relayd_socket(int domain, struct ltt_session *session,
 535                 struct lttng_uri *relayd_uri, struct consumer_output *consumer,
 536                 struct consumer_socket *consumer_sock)
 537 {
 538         int ret;
 539         struct lttcomm_sock *sock = NULL;
 540
 541         /* Set the network sequence index if not set. */
 542         if (consumer->net_seq_index == -1) {
 543                 /*
 544                  * Increment net_seq_idx because we are about to transfer the
 545                  * new relayd socket to the consumer.
 546                  */
 547                 uatomic_inc(&relayd_net_seq_idx);
 548                 /* Assign unique key so the consumer can match streams */
 549                 uatomic_set(&consumer->net_seq_index,
 550                                 uatomic_read(&relayd_net_seq_idx));
 551         }
 552
 553         /* Connect to relayd and make version check if uri is the control. */
 554         ret = create_connect_relayd(consumer, session->name, relayd_uri, &sock);
 555         if (ret != LTTNG_OK) {
 556                 goto close_sock;
 557         }
 558
 559         /* If the control socket is connected, network session is ready */
 560         if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
 561                 session->net_handle = 1;
 562         }
 563
 564         /* Send relayd socket to consumer. */
 565         ret = consumer_send_relayd_socket(consumer_sock, sock,
 566                         consumer, relayd_uri->stype, session->id);
 567         if (ret < 0) {
 568                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
 569                 goto close_sock;
 570         }
 571
 572         /* Flag that the corresponding socket was sent. */
 573         if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
 574                 consumer->dst.net.control_sock_sent = 1;
 575         } else if (relayd_uri->stype == LTTNG_STREAM_DATA) {
 576                 consumer->dst.net.data_sock_sent = 1;
 577         }
 578
 579         ret = LTTNG_OK;
 580
 581         /*
 582          * Close socket which was dup on the consumer side. The session daemon does
 583          * NOT keep track of the relayd socket(s) once transfer to the consumer.
 584          */
 585
 586 close_sock:
 587         if (sock) {
 588                 (void) relayd_close(sock);
 589                 lttcomm_destroy_sock(sock);
 590         }
 591
 592         return ret;
 593 }
 594
 595 /*
 596  * Send both relayd sockets to a specific consumer and domain.  This is a
 597  * helper function to facilitate sending the information to the consumer for a
 598  * session.
 599  */
 600 static int send_consumer_relayd_sockets(int domain,
 601                 struct ltt_session *session, struct consumer_output *consumer,
 602                 struct consumer_socket *sock)
 603 {
 604         int ret = LTTNG_OK;
 605
 606         assert(session);
 607         assert(consumer);
 608
 609         /* Sending control relayd socket. */
 610         if (!consumer->dst.net.control_sock_sent) {
 611                 ret = send_consumer_relayd_socket(domain, session,
 612                                 &consumer->dst.net.control, consumer, sock);
 613                 if (ret != LTTNG_OK) {
 614                         goto error;
 615                 }
 616         }
 617
 618         /* Sending data relayd socket. */
 619         if (!consumer->dst.net.data_sock_sent) {
 620                 ret = send_consumer_relayd_socket(domain, session,
 621                                 &consumer->dst.net.data, consumer, sock);
 622                 if (ret != LTTNG_OK) {
 623                         goto error;
 624                 }
 625         }
 626
 627 error:
 628         return ret;
 629 }
 630
 631 /*
 632  * Setup relayd connections for a tracing session. First creates the socket to
 633  * the relayd and send them to the right domain consumer. Consumer type MUST be
 634  * network.
 635  */
 636 static int setup_relayd(struct ltt_session *session)
 637 {
 638         int ret = LTTNG_OK;
 639         struct ltt_ust_session *usess;
 640         struct ltt_kernel_session *ksess;
 641         struct consumer_socket *socket;
 642         struct lttng_ht_iter iter;
 643
 644         assert(session);
 645
 646         usess = session->ust_session;
 647         ksess = session->kernel_session;
 648
 649         DBG2("Setting relayd for session %s", session->name);
 650
 651         rcu_read_lock();
 652
 653         if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
 654                         && usess->consumer->enabled) {
 655                 /* For each consumer socket, send relayd sockets */
 656                 cds_lfht_for_each_entry(usess->consumer->socks->ht, &iter.iter,
 657                                 socket, node.node) {
 658                         /* Code flow error */
 659                         assert(socket->fd >= 0);
 660
 661                         pthread_mutex_lock(socket->lock);
 662                         ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session,
 663                                         usess->consumer, socket);
 664                         pthread_mutex_unlock(socket->lock);
 665                         if (ret != LTTNG_OK) {
 666                                 goto error;
 667                         }
 668                 }
 669         }
 670
 671         if (ksess && ksess->consumer && ksess->consumer->type == CONSUMER_DST_NET
 672                         && ksess->consumer->enabled) {
 673                 cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
 674                                 socket, node.node) {
 675                         /* Code flow error */
 676                         assert(socket->fd >= 0);
 677
 678                         pthread_mutex_lock(socket->lock);
 679                         ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session,
 680                                         ksess->consumer, socket);
 681                         pthread_mutex_unlock(socket->lock);
 682                         if (ret != LTTNG_OK) {
 683                                 goto error;
 684                         }
 685                 }
 686         }
 687
 688 error:
 689         rcu_read_unlock();
 690         return ret;
 691 }
 692
 693 /*
 694  * Start a kernel session by opening all necessary streams.
 695  */
 696 static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
 697 {
 698         int ret;
 699         struct ltt_kernel_channel *kchan;
 700
 701         /* Open kernel metadata */
 702         if (ksess->metadata == NULL) {
 703                 ret = kernel_open_metadata(ksess);
 704                 if (ret < 0) {
 705                         ret = LTTNG_ERR_KERN_META_FAIL;
 706                         goto error;
 707                 }
 708         }
 709
 710         /* Open kernel metadata stream */
 711         if (ksess->metadata_stream_fd < 0) {
 712                 ret = kernel_open_metadata_stream(ksess);
 713                 if (ret < 0) {
 714                         ERR("Kernel create metadata stream failed");
 715                         ret = LTTNG_ERR_KERN_STREAM_FAIL;
 716                         goto error;
 717                 }
 718         }
 719
 720         /* For each channel */
 721         cds_list_for_each_entry(kchan, &ksess->channel_list.head, list) {
 722                 if (kchan->stream_count == 0) {
 723                         ret = kernel_open_channel_stream(kchan);
 724                         if (ret < 0) {
 725                                 ret = LTTNG_ERR_KERN_STREAM_FAIL;
 726                                 goto error;
 727                         }
 728                         /* Update the stream global counter */
 729                         ksess->stream_count_global += ret;
 730                 }
 731         }
 732
 733         /* Setup kernel consumer socket and send fds to it */
 734         ret = init_kernel_tracing(ksess);
 735         if (ret < 0) {
 736                 ret = LTTNG_ERR_KERN_START_FAIL;
 737                 goto error;
 738         }
 739
 740         /* This start the kernel tracing */
 741         ret = kernel_start_session(ksess);
 742         if (ret < 0) {
 743                 ret = LTTNG_ERR_KERN_START_FAIL;
 744                 goto error;
 745         }
 746
 747         /* Quiescent wait after starting trace */
 748         kernel_wait_quiescent(kernel_tracer_fd);
 749
 750         ksess->started = 1;
 751
 752         ret = LTTNG_OK;
 753
 754 error:
 755         return ret;
 756 }
 757
 758 /*
 759  * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
 760  */
 761 int cmd_disable_channel(struct ltt_session *session, int domain,
 762                 char *channel_name)
 763 {
 764         int ret;
 765         struct ltt_ust_session *usess;
 766
 767         usess = session->ust_session;
 768
 769         rcu_read_lock();
 770
 771         switch (domain) {
 772         case LTTNG_DOMAIN_KERNEL:
 773         {
 774                 ret = channel_kernel_disable(session->kernel_session,
 775                                 channel_name);
 776                 if (ret != LTTNG_OK) {
 777                         goto error;
 778                 }
 779
 780                 kernel_wait_quiescent(kernel_tracer_fd);
 781                 break;
 782         }
 783         case LTTNG_DOMAIN_UST:
 784         {
 785                 struct ltt_ust_channel *uchan;
 786                 struct lttng_ht *chan_ht;
 787
 788                 chan_ht = usess->domain_global.channels;
 789
 790                 uchan = trace_ust_find_channel_by_name(chan_ht, channel_name);
 791                 if (uchan == NULL) {
 792                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 793                         goto error;
 794                 }
 795
 796                 ret = channel_ust_disable(usess, domain, uchan);
 797                 if (ret != LTTNG_OK) {
 798                         goto error;
 799                 }
 800                 break;
 801         }
 802 #if 0
 803         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 804         case LTTNG_DOMAIN_UST_EXEC_NAME:
 805         case LTTNG_DOMAIN_UST_PID:
 806 #endif
 807         default:
 808                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
 809                 goto error;
 810         }
 811
 812         ret = LTTNG_OK;
 813
 814 error:
 815         rcu_read_unlock();
 816         return ret;
 817 }
 818
 819 /*
 820  * Command LTTNG_ENABLE_CHANNEL processed by the client thread.
 821  *
 822  * The wpipe arguments is used as a notifier for the kernel thread.
 823  */
 824 int cmd_enable_channel(struct ltt_session *session,
 825                 int domain, struct lttng_channel *attr, int wpipe)
 826 {
 827         int ret;
 828         struct ltt_ust_session *usess = session->ust_session;
 829         struct lttng_ht *chan_ht;
 830
 831         assert(session);
 832         assert(attr);
 833
 834         DBG("Enabling channel %s for session %s", attr->name, session->name);
 835
 836         rcu_read_lock();
 837
 838         switch (domain) {
 839         case LTTNG_DOMAIN_KERNEL:
 840         {
 841                 struct ltt_kernel_channel *kchan;
 842
 843                 kchan = trace_kernel_get_channel_by_name(attr->name,
 844                                 session->kernel_session);
 845                 if (kchan == NULL) {
 846                         ret = channel_kernel_create(session->kernel_session, attr, wpipe);
 847                 } else {
 848                         ret = channel_kernel_enable(session->kernel_session, kchan);
 849                 }
 850
 851                 if (ret != LTTNG_OK) {
 852                         goto error;
 853                 }
 854
 855                 kernel_wait_quiescent(kernel_tracer_fd);
 856
 857                 /*
 858                  * If the session was previously started, start as well this newly
 859                  * created kernel session so the events/channels enabled *after* the
 860                  * start actually work.
 861                  */
 862                 if (session->started && !session->kernel_session->started) {
 863                         ret = start_kernel_session(session->kernel_session, wpipe);
 864                         if (ret != LTTNG_OK) {
 865                                 goto error;
 866                         }
 867                 }
 868                 break;
 869         }
 870         case LTTNG_DOMAIN_UST:
 871         {
 872                 struct ltt_ust_channel *uchan;
 873
 874                 chan_ht = usess->domain_global.channels;
 875
 876                 uchan = trace_ust_find_channel_by_name(chan_ht, attr->name);
 877                 if (uchan == NULL) {
 878                         ret = channel_ust_create(usess, domain, attr);
 879                 } else {
 880                         ret = channel_ust_enable(usess, domain, uchan);
 881                 }
 882
 883                 /* Start the UST session if the session was already started. */
 884                 if (session->started && !usess->start_trace) {
 885                         ret = ust_app_start_trace_all(usess);
 886                         if (ret < 0) {
 887                                 ret = LTTNG_ERR_UST_START_FAIL;
 888                                 goto error;
 889                         }
 890                         ret = LTTNG_OK;
 891                         usess->start_trace = 1;
 892                 }
 893                 break;
 894         }
 895 #if 0
 896         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 897         case LTTNG_DOMAIN_UST_EXEC_NAME:
 898         case LTTNG_DOMAIN_UST_PID:
 899 #endif
 900         default:
 901                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
 902                 goto error;
 903         }
 904
 905 error:
 906         rcu_read_unlock();
 907         return ret;
 908 }
 909
 910
 911 /*
 912  * Command LTTNG_DISABLE_EVENT processed by the client thread.
 913  */
 914 int cmd_disable_event(struct ltt_session *session, int domain,
 915                 char *channel_name, char *event_name)
 916 {
 917         int ret;
 918
 919         rcu_read_lock();
 920
 921         switch (domain) {
 922         case LTTNG_DOMAIN_KERNEL:
 923         {
 924                 struct ltt_kernel_channel *kchan;
 925                 struct ltt_kernel_session *ksess;
 926
 927                 ksess = session->kernel_session;
 928
 929                 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
 930                 if (kchan == NULL) {
 931                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 932                         goto error;
 933                 }
 934
 935                 ret = event_kernel_disable_tracepoint(kchan, event_name);
 936                 if (ret != LTTNG_OK) {
 937                         goto error;
 938                 }
 939
 940                 kernel_wait_quiescent(kernel_tracer_fd);
 941                 break;
 942         }
 943         case LTTNG_DOMAIN_UST:
 944         {
 945                 struct ltt_ust_channel *uchan;
 946                 struct ltt_ust_session *usess;
 947
 948                 usess = session->ust_session;
 949
 950                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 951                                 channel_name);
 952                 if (uchan == NULL) {
 953                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 954                         goto error;
 955                 }
 956
 957                 ret = event_ust_disable_tracepoint(usess, domain, uchan, event_name);
 958                 if (ret != LTTNG_OK) {
 959                         goto error;
 960                 }
 961
 962                 DBG3("Disable UST event %s in channel %s completed", event_name,
 963                                 channel_name);
 964                 break;
 965         }
 966 #if 0
 967         case LTTNG_DOMAIN_UST_EXEC_NAME:
 968         case LTTNG_DOMAIN_UST_PID:
 969         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 970 #endif
 971         default:
 972                 ret = LTTNG_ERR_UND;
 973                 goto error;
 974         }
 975
 976         ret = LTTNG_OK;
 977
 978 error:
 979         rcu_read_unlock();
 980         return ret;
 981 }
 982
 983 /*
 984  * Command LTTNG_DISABLE_ALL_EVENT processed by the client thread.
 985  */
 986 int cmd_disable_event_all(struct ltt_session *session, int domain,
 987                 char *channel_name)
 988 {
 989         int ret;
 990
 991         rcu_read_lock();
 992
 993         switch (domain) {
 994         case LTTNG_DOMAIN_KERNEL:
 995         {
 996                 struct ltt_kernel_session *ksess;
 997                 struct ltt_kernel_channel *kchan;
 998
 999                 ksess = session->kernel_session;
1000
1001                 kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
1002                 if (kchan == NULL) {
1003                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
1004                         goto error;
1005                 }
1006
1007                 ret = event_kernel_disable_all(kchan);
1008                 if (ret != LTTNG_OK) {
1009                         goto error;
1010                 }
1011
1012                 kernel_wait_quiescent(kernel_tracer_fd);
1013                 break;
1014         }
1015         case LTTNG_DOMAIN_UST:
1016         {
1017                 struct ltt_ust_session *usess;
1018                 struct ltt_ust_channel *uchan;
1019
1020                 usess = session->ust_session;
1021
1022                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1023                                 channel_name);
1024                 if (uchan == NULL) {
1025                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1026                         goto error;
1027                 }
1028
1029                 ret = event_ust_disable_all_tracepoints(usess, domain, uchan);
1030                 if (ret != 0) {
1031                         goto error;
1032                 }
1033
1034                 DBG3("Disable all UST events in channel %s completed", channel_name);
1035
1036                 break;
1037         }
1038 #if 0
1039         case LTTNG_DOMAIN_UST_EXEC_NAME:
1040         case LTTNG_DOMAIN_UST_PID:
1041         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1042 #endif
1043         default:
1044                 ret = LTTNG_ERR_UND;
1045                 goto error;
1046         }
1047
1048         ret = LTTNG_OK;
1049
1050 error:
1051         rcu_read_unlock();
1052         return ret;
1053 }
1054
1055 /*
1056  * Command LTTNG_ADD_CONTEXT processed by the client thread.
1057  */
1058 int cmd_add_context(struct ltt_session *session, int domain,
1059                 char *channel_name, struct lttng_event_context *ctx, int kwpipe)
1060 {
1061         int ret;
1062
1063         switch (domain) {
1064         case LTTNG_DOMAIN_KERNEL:
1065                 assert(session->kernel_session);
1066
1067                 if (session->kernel_session->channel_count == 0) {
1068                         /* Create default channel */
1069                         ret = channel_kernel_create(session->kernel_session, NULL, kwpipe);
1070                         if (ret != LTTNG_OK) {
1071                                 goto error;
1072                         }
1073                 }
1074
1075                 /* Add kernel context to kernel tracer */
1076                 ret = context_kernel_add(session->kernel_session, ctx, channel_name);
1077                 if (ret != LTTNG_OK) {
1078                         goto error;
1079                 }
1080                 break;
1081         case LTTNG_DOMAIN_UST:
1082         {
1083                 struct ltt_ust_session *usess = session->ust_session;
1084                 assert(usess);
1085
1086                 unsigned int chan_count =
1087                         lttng_ht_get_count(usess->domain_global.channels);
1088                 if (chan_count == 0) {
1089                         struct lttng_channel *attr;
1090                         /* Create default channel */
1091                         attr = channel_new_default_attr(domain);
1092                         if (attr == NULL) {
1093                                 ret = LTTNG_ERR_FATAL;
1094                                 goto error;
1095                         }
1096
1097                         ret = channel_ust_create(usess, domain, attr);
1098                         if (ret != LTTNG_OK) {
1099                                 free(attr);
1100                                 goto error;
1101                         }
1102                         free(attr);
1103                 }
1104
1105                 ret = context_ust_add(usess, domain, ctx, channel_name);
1106                 if (ret != LTTNG_OK) {
1107                         goto error;
1108                 }
1109                 break;
1110         }
1111 #if 0
1112         case LTTNG_DOMAIN_UST_EXEC_NAME:
1113         case LTTNG_DOMAIN_UST_PID:
1114         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1115 #endif
1116         default:
1117                 ret = LTTNG_ERR_UND;
1118                 goto error;
1119         }
1120
1121         ret = LTTNG_OK;
1122
1123 error:
1124         return ret;
1125 }
1126
1127 /*
1128  * Command LTTNG_ENABLE_EVENT processed by the client thread.
1129  */
1130 int cmd_enable_event(struct ltt_session *session, int domain,
1131                 char *channel_name, struct lttng_event *event,
1132                 struct lttng_filter_bytecode *filter, int wpipe)
1133 {
1134         int ret, channel_created = 0;
1135         struct lttng_channel *attr;
1136
1137         assert(session);
1138         assert(event);
1139         assert(channel_name);
1140
1141         rcu_read_lock();
1142
1143         switch (domain) {
1144         case LTTNG_DOMAIN_KERNEL:
1145         {
1146                 struct ltt_kernel_channel *kchan;
1147
1148                 kchan = trace_kernel_get_channel_by_name(channel_name,
1149                                 session->kernel_session);
1150                 if (kchan == NULL) {
1151                         attr = channel_new_default_attr(domain);
1152                         if (attr == NULL) {
1153                                 ret = LTTNG_ERR_FATAL;
1154                                 goto error;
1155                         }
1156                         strncpy(attr->name, channel_name, sizeof(attr->name));
1157
1158                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1159                         if (ret != LTTNG_OK) {
1160                                 free(attr);
1161                                 goto error;
1162                         }
1163                         free(attr);
1164
1165                         channel_created = 1;
1166                 }
1167
1168                 /* Get the newly created kernel channel pointer */
1169                 kchan = trace_kernel_get_channel_by_name(channel_name,
1170                                 session->kernel_session);
1171                 if (kchan == NULL) {
1172                         /* This sould not happen... */
1173                         ret = LTTNG_ERR_FATAL;
1174                         goto error;
1175                 }
1176
1177                 ret = event_kernel_enable_tracepoint(kchan, event);
1178                 if (ret != LTTNG_OK) {
1179                         if (channel_created) {
1180                                 /* Let's not leak a useless channel. */
1181                                 kernel_destroy_channel(kchan);
1182                         }
1183                         goto error;
1184                 }
1185
1186                 kernel_wait_quiescent(kernel_tracer_fd);
1187                 break;
1188         }
1189         case LTTNG_DOMAIN_UST:
1190         {
1191                 struct ltt_ust_channel *uchan;
1192                 struct ltt_ust_session *usess = session->ust_session;
1193
1194                 assert(usess);
1195
1196                 /* Get channel from global UST domain */
1197                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1198                                 channel_name);
1199                 if (uchan == NULL) {
1200                         /* Create default channel */
1201                         attr = channel_new_default_attr(domain);
1202                         if (attr == NULL) {
1203                                 ret = LTTNG_ERR_FATAL;
1204                                 goto error;
1205                         }
1206                         strncpy(attr->name, channel_name, sizeof(attr->name));
1207
1208                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1209                         if (ret != LTTNG_OK) {
1210                                 free(attr);
1211                                 goto error;
1212                         }
1213                         free(attr);
1214
1215                         /* Get the newly created channel reference back */
1216                         uchan = trace_ust_find_channel_by_name(
1217                                         usess->domain_global.channels, channel_name);
1218                         assert(uchan);
1219                 }
1220
1221                 /* At this point, the session and channel exist on the tracer */
1222                 ret = event_ust_enable_tracepoint(usess, domain, uchan, event, filter);
1223                 if (ret != LTTNG_OK) {
1224                         goto error;
1225                 }
1226                 break;
1227         }
1228 #if 0
1229         case LTTNG_DOMAIN_UST_EXEC_NAME:
1230         case LTTNG_DOMAIN_UST_PID:
1231         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1232 #endif
1233         default:
1234                 ret = LTTNG_ERR_UND;
1235                 goto error;
1236         }
1237
1238         ret = LTTNG_OK;
1239
1240 error:
1241         rcu_read_unlock();
1242         return ret;
1243 }
1244
1245 /*
1246  * Command LTTNG_ENABLE_ALL_EVENT processed by the client thread.
1247  */
1248 int cmd_enable_event_all(struct ltt_session *session, int domain,
1249                 char *channel_name, int event_type,
1250                 struct lttng_filter_bytecode *filter, int wpipe)
1251 {
1252         int ret;
1253         struct lttng_channel *attr;
1254
1255         assert(session);
1256         assert(channel_name);
1257
1258         rcu_read_lock();
1259
1260         switch (domain) {
1261         case LTTNG_DOMAIN_KERNEL:
1262         {
1263                 struct ltt_kernel_channel *kchan;
1264
1265                 assert(session->kernel_session);
1266
1267                 kchan = trace_kernel_get_channel_by_name(channel_name,
1268                                 session->kernel_session);
1269                 if (kchan == NULL) {
1270                         /* Create default channel */
1271                         attr = channel_new_default_attr(domain);
1272                         if (attr == NULL) {
1273                                 ret = LTTNG_ERR_FATAL;
1274                                 goto error;
1275                         }
1276                         strncpy(attr->name, channel_name, sizeof(attr->name));
1277
1278                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1279                         if (ret != LTTNG_OK) {
1280                                 free(attr);
1281                                 goto error;
1282                         }
1283                         free(attr);
1284
1285                         /* Get the newly created kernel channel pointer */
1286                         kchan = trace_kernel_get_channel_by_name(channel_name,
1287                                         session->kernel_session);
1288                         assert(kchan);
1289                 }
1290
1291                 switch (event_type) {
1292                 case LTTNG_EVENT_SYSCALL:
1293                         ret = event_kernel_enable_all_syscalls(kchan, kernel_tracer_fd);
1294                         break;
1295                 case LTTNG_EVENT_TRACEPOINT:
1296                         /*
1297                          * This call enables all LTTNG_KERNEL_TRACEPOINTS and
1298                          * events already registered to the channel.
1299                          */
1300                         ret = event_kernel_enable_all_tracepoints(kchan, kernel_tracer_fd);
1301                         break;
1302                 case LTTNG_EVENT_ALL:
1303                         /* Enable syscalls and tracepoints */
1304                         ret = event_kernel_enable_all(kchan, kernel_tracer_fd);
1305                         break;
1306                 default:
1307                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
1308                         goto error;
1309                 }
1310
1311                 /* Manage return value */
1312                 if (ret != LTTNG_OK) {
1313                         /*
1314                          * On error, cmd_enable_channel call will take care of destroying
1315                          * the created channel if it was needed.
1316                          */
1317                         goto error;
1318                 }
1319
1320                 kernel_wait_quiescent(kernel_tracer_fd);
1321                 break;
1322         }
1323         case LTTNG_DOMAIN_UST:
1324         {
1325                 struct ltt_ust_channel *uchan;
1326                 struct ltt_ust_session *usess = session->ust_session;
1327
1328                 assert(usess);
1329
1330                 /* Get channel from global UST domain */
1331                 uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
1332                                 channel_name);
1333                 if (uchan == NULL) {
1334                         /* Create default channel */
1335                         attr = channel_new_default_attr(domain);
1336                         if (attr == NULL) {
1337                                 ret = LTTNG_ERR_FATAL;
1338                                 goto error;
1339                         }
1340                         strncpy(attr->name, channel_name, sizeof(attr->name));
1341
1342                         ret = cmd_enable_channel(session, domain, attr, wpipe);
1343                         if (ret != LTTNG_OK) {
1344                                 free(attr);
1345                                 goto error;
1346                         }
1347                         free(attr);
1348
1349                         /* Get the newly created channel reference back */
1350                         uchan = trace_ust_find_channel_by_name(
1351                                         usess->domain_global.channels, channel_name);
1352                         assert(uchan);
1353                 }
1354
1355                 /* At this point, the session and channel exist on the tracer */
1356
1357                 switch (event_type) {
1358                 case LTTNG_EVENT_ALL:
1359                 case LTTNG_EVENT_TRACEPOINT:
1360                         ret = event_ust_enable_all_tracepoints(usess, domain, uchan,
1361                                         filter);
1362                         if (ret != LTTNG_OK) {
1363                                 goto error;
1364                         }
1365                         break;
1366                 default:
1367                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
1368                         goto error;
1369                 }
1370
1371                 /* Manage return value */
1372                 if (ret != LTTNG_OK) {
1373                         goto error;
1374                 }
1375
1376                 break;
1377         }
1378 #if 0
1379         case LTTNG_DOMAIN_UST_EXEC_NAME:
1380         case LTTNG_DOMAIN_UST_PID:
1381         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1382 #endif
1383         default:
1384                 ret = LTTNG_ERR_UND;
1385                 goto error;
1386         }
1387
1388         ret = LTTNG_OK;
1389
1390 error:
1391         rcu_read_unlock();
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);
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 = close(sock);
1917                         if (ret < 0) {
1918                                 PERROR("close register consumer");
1919                         }
1920                         ret = LTTNG_ERR_FATAL;
1921                         goto error;
1922                 }
1923
1924                 socket->lock = zmalloc(sizeof(pthread_mutex_t));
1925                 if (socket->lock == NULL) {
1926                         PERROR("zmalloc pthread mutex");
1927                         ret = LTTNG_ERR_FATAL;
1928                         goto error;
1929                 }
1930                 pthread_mutex_init(socket->lock, NULL);
1931                 socket->registered = 1;
1932
1933                 rcu_read_lock();
1934                 consumer_add_socket(socket, ksess->consumer);
1935                 rcu_read_unlock();
1936
1937                 pthread_mutex_lock(&cdata->pid_mutex);
1938                 cdata->pid = -1;
1939                 pthread_mutex_unlock(&cdata->pid_mutex);
1940
1941                 break;
1942         }
1943         default:
1944                 /* TODO: Userspace tracing */
1945                 ret = LTTNG_ERR_UND;
1946                 goto error;
1947         }
1948
1949         ret = LTTNG_OK;
1950
1951 error:
1952         return ret;
1953 }
1954
1955 /*
1956  * Command LTTNG_LIST_DOMAINS processed by the client thread.
1957  */
1958 ssize_t cmd_list_domains(struct ltt_session *session,
1959                 struct lttng_domain **domains)
1960 {
1961         int ret, index = 0;
1962         ssize_t nb_dom = 0;
1963
1964         if (session->kernel_session != NULL) {
1965                 DBG3("Listing domains found kernel domain");
1966                 nb_dom++;
1967         }
1968
1969         if (session->ust_session != NULL) {
1970                 DBG3("Listing domains found UST global domain");
1971                 nb_dom++;
1972         }
1973
1974         *domains = zmalloc(nb_dom * sizeof(struct lttng_domain));
1975         if (*domains == NULL) {
1976                 ret = LTTNG_ERR_FATAL;
1977                 goto error;
1978         }
1979
1980         if (session->kernel_session != NULL) {
1981                 (*domains)[index].type = LTTNG_DOMAIN_KERNEL;
1982                 index++;
1983         }
1984
1985         if (session->ust_session != NULL) {
1986                 (*domains)[index].type = LTTNG_DOMAIN_UST;
1987                 index++;
1988         }
1989
1990         return nb_dom;
1991
1992 error:
1993         /* Return negative value to differentiate return code */
1994         return -ret;
1995 }
1996
1997
1998 /*
1999  * Command LTTNG_LIST_CHANNELS processed by the client thread.
2000  */
2001 ssize_t cmd_list_channels(int domain, struct ltt_session *session,
2002                 struct lttng_channel **channels)
2003 {
2004         int ret;
2005         ssize_t nb_chan = 0;
2006
2007         switch (domain) {
2008         case LTTNG_DOMAIN_KERNEL:
2009                 if (session->kernel_session != NULL) {
2010                         nb_chan = session->kernel_session->channel_count;
2011                 }
2012                 DBG3("Number of kernel channels %zd", nb_chan);
2013                 if (nb_chan <= 0) {
2014                         ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
2015                 }
2016                 break;
2017         case LTTNG_DOMAIN_UST:
2018                 if (session->ust_session != NULL) {
2019                         nb_chan = lttng_ht_get_count(
2020                                         session->ust_session->domain_global.channels);
2021                 }
2022                 DBG3("Number of UST global channels %zd", nb_chan);
2023                 if (nb_chan <= 0) {
2024                         ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
2025                 }
2026                 break;
2027         default:
2028                 *channels = NULL;
2029                 ret = LTTNG_ERR_UND;
2030                 goto error;
2031         }
2032
2033         if (nb_chan > 0) {
2034                 *channels = zmalloc(nb_chan * sizeof(struct lttng_channel));
2035                 if (*channels == NULL) {
2036                         ret = LTTNG_ERR_FATAL;
2037                         goto error;
2038                 }
2039
2040                 list_lttng_channels(domain, session, *channels);
2041         } else {
2042                 *channels = NULL;
2043                 /* Ret value was set in the domain switch case */
2044                 goto error;
2045         }
2046
2047         return nb_chan;
2048
2049 error:
2050         /* Return negative value to differentiate return code */
2051         return -ret;
2052 }
2053
2054 /*
2055  * Command LTTNG_LIST_EVENTS processed by the client thread.
2056  */
2057 ssize_t cmd_list_events(int domain, struct ltt_session *session,
2058                 char *channel_name, struct lttng_event **events)
2059 {
2060         int ret = 0;
2061         ssize_t nb_event = 0;
2062
2063         switch (domain) {
2064         case LTTNG_DOMAIN_KERNEL:
2065                 if (session->kernel_session != NULL) {
2066                         nb_event = list_lttng_kernel_events(channel_name,
2067                                         session->kernel_session, events);
2068                 }
2069                 break;
2070         case LTTNG_DOMAIN_UST:
2071         {
2072                 if (session->ust_session != NULL) {
2073                         nb_event = list_lttng_ust_global_events(channel_name,
2074                                         &session->ust_session->domain_global, events);
2075                 }
2076                 break;
2077         }
2078         default:
2079                 ret = LTTNG_ERR_UND;
2080                 goto error;
2081         }
2082
2083         return nb_event;
2084
2085 error:
2086         /* Return negative value to differentiate return code */
2087         return -ret;
2088 }
2089
2090 /*
2091  * Using the session list, filled a lttng_session array to send back to the
2092  * client for session listing.
2093  *
2094  * The session list lock MUST be acquired before calling this function. Use
2095  * session_lock_list() and session_unlock_list().
2096  */
2097 void cmd_list_lttng_sessions(struct lttng_session *sessions, uid_t uid,
2098                 gid_t gid)
2099 {
2100         int ret;
2101         unsigned int i = 0;
2102         struct ltt_session *session;
2103         struct ltt_session_list *list = session_get_list();
2104
2105         DBG("Getting all available session for UID %d GID %d",
2106                         uid, gid);
2107         /*
2108          * Iterate over session list and append data after the control struct in
2109          * the buffer.
2110          */
2111         cds_list_for_each_entry(session, &list->head, list) {
2112                 /*
2113                  * Only list the sessions the user can control.
2114                  */
2115                 if (!session_access_ok(session, uid, gid)) {
2116                         continue;
2117                 }
2118
2119                 struct ltt_kernel_session *ksess = session->kernel_session;
2120                 struct ltt_ust_session *usess = session->ust_session;
2121
2122                 if (session->consumer->type == CONSUMER_DST_NET ||
2123                                 (ksess && ksess->consumer->type == CONSUMER_DST_NET) ||
2124                                 (usess && usess->consumer->type == CONSUMER_DST_NET)) {
2125                         ret = build_network_session_path(sessions[i].path,
2126                                         sizeof(session[i].path), session);
2127                 } else {
2128                         ret = snprintf(sessions[i].path, sizeof(session[i].path), "%s",
2129                                         session->consumer->dst.trace_path);
2130                 }
2131                 if (ret < 0) {
2132                         PERROR("snprintf session path");
2133                         continue;
2134                 }
2135
2136                 strncpy(sessions[i].name, session->name, NAME_MAX);
2137                 sessions[i].name[NAME_MAX - 1] = '\0';
2138                 sessions[i].enabled = session->enabled;
2139                 i++;
2140         }
2141 }
2142
2143 /*
2144  * Command LTTNG_DISABLE_CONSUMER processed by the client thread.
2145  */
2146 int cmd_disable_consumer(int domain, struct ltt_session *session)
2147 {
2148         int ret;
2149         struct ltt_kernel_session *ksess = session->kernel_session;
2150         struct ltt_ust_session *usess = session->ust_session;
2151         struct consumer_output *consumer;
2152
2153         assert(session);
2154
2155         if (session->enabled) {
2156                 /* Can't disable consumer on an already started session */
2157                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2158                 goto error;
2159         }
2160
2161         if (!session->start_consumer) {
2162                 ret = LTTNG_ERR_NO_CONSUMER;
2163                 goto error;
2164         }
2165
2166         switch (domain) {
2167         case 0:
2168                 DBG("Disable tracing session %s consumer", session->name);
2169                 consumer = session->consumer;
2170                 break;
2171         case LTTNG_DOMAIN_KERNEL:
2172                 /* Code flow error if we don't have a kernel session here. */
2173                 assert(ksess);
2174
2175                 DBG("Disabling kernel consumer");
2176                 consumer = ksess->consumer;
2177
2178                 break;
2179         case LTTNG_DOMAIN_UST:
2180                 /* Code flow error if we don't have a UST session here. */
2181                 assert(usess);
2182
2183                 DBG("Disabling UST consumer");
2184                 consumer = usess->consumer;
2185
2186                 break;
2187         default:
2188                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
2189                 goto error;
2190         }
2191
2192         if (consumer) {
2193                 consumer->enabled = 0;
2194                 /* Success at this point */
2195                 ret = LTTNG_OK;
2196         } else {
2197                 ret = LTTNG_ERR_NO_CONSUMER;
2198         }
2199
2200 error:
2201         return ret;
2202 }
2203
2204 /*
2205  * Command LTTNG_ENABLE_CONSUMER processed by the client thread.
2206  */
2207 int cmd_enable_consumer(int domain, struct ltt_session *session)
2208 {
2209         int ret;
2210         struct ltt_kernel_session *ksess = session->kernel_session;
2211         struct ltt_ust_session *usess = session->ust_session;
2212         struct consumer_output *consumer = NULL;
2213
2214         assert(session);
2215
2216         /* Can't enable consumer after session started. */
2217         if (session->enabled) {
2218                 ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
2219                 goto error;
2220         }
2221
2222         switch (domain) {
2223         case 0:
2224                 assert(session->consumer);
2225                 consumer = session->consumer;
2226                 break;
2227         case LTTNG_DOMAIN_KERNEL:
2228                 /* Code flow error if we don't have a kernel session here. */
2229                 assert(ksess);
2230
2231                 /*
2232                  * Check if we have already sent fds to the consumer. In that case,
2233                  * the enable-consumer command can't be used because a start trace
2234                  * had previously occured.
2235                  */
2236                 if (ksess->consumer_fds_sent) {
2237                         ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2238                         goto error;
2239                 }
2240
2241                 consumer = ksess->tmp_consumer;
2242                 if (consumer == NULL) {
2243                         ret = LTTNG_OK;
2244                         /* No temp. consumer output exists. Using the current one. */
2245                         DBG3("No temporary consumer. Using default");
2246                         consumer = ksess->consumer;
2247                         goto error;
2248                 }
2249
2250                 switch (consumer->type) {
2251                 case CONSUMER_DST_LOCAL:
2252                         DBG2("Consumer output is local. Creating directory(ies)");
2253
2254                         /* Create directory(ies) */
2255                         ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2256                                         S_IRWXU | S_IRWXG, session->uid, session->gid);
2257                         if (ret < 0) {
2258                                 if (ret != -EEXIST) {
2259                                         ERR("Trace directory creation error");
2260                                         ret = LTTNG_ERR_FATAL;
2261                                         goto error;
2262                                 }
2263                         }
2264                         break;
2265                 case CONSUMER_DST_NET:
2266                         DBG2("Consumer output is network. Validating URIs");
2267                         /* Validate if we have both control and data path set. */
2268                         if (!consumer->dst.net.control_isset) {
2269                                 ret = LTTNG_ERR_URL_CTRL_MISS;
2270                                 goto error;
2271                         }
2272
2273                         if (!consumer->dst.net.data_isset) {
2274                                 ret = LTTNG_ERR_URL_DATA_MISS;
2275                                 goto error;
2276                         }
2277
2278                         /* Check established network session state */
2279                         if (session->net_handle == 0) {
2280                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2281                                 ERR("Session network handle is not set on enable-consumer");
2282                                 goto error;
2283                         }
2284
2285                         break;
2286                 }
2287
2288                 /*
2289                  * @session-lock
2290                  * This is race free for now since the session lock is acquired before
2291                  * ending up in this function. No other threads can access this kernel
2292                  * session without this lock hence freeing the consumer output object
2293                  * is valid.
2294                  */
2295                 rcu_read_lock();
2296                 /* Destroy current consumer. We are about to replace it */
2297                 consumer_destroy_output(ksess->consumer);
2298                 rcu_read_unlock();
2299                 ksess->consumer = consumer;
2300                 ksess->tmp_consumer = NULL;
2301
2302                 break;
2303         case LTTNG_DOMAIN_UST:
2304                 /* Code flow error if we don't have a UST session here. */
2305                 assert(usess);
2306
2307                 /*
2308                  * Check if we have already sent fds to the consumer. In that case,
2309                  * the enable-consumer command can't be used because a start trace
2310                  * had previously occured.
2311                  */
2312                 if (usess->start_trace) {
2313                         ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2314                         goto error;
2315                 }
2316
2317                 consumer = usess->tmp_consumer;
2318                 if (consumer == NULL) {
2319                         ret = LTTNG_OK;
2320                         /* No temp. consumer output exists. Using the current one. */
2321                         DBG3("No temporary consumer. Using default");
2322                         consumer = usess->consumer;
2323                         goto error;
2324                 }
2325
2326                 switch (consumer->type) {
2327                 case CONSUMER_DST_LOCAL:
2328                         DBG2("Consumer output is local. Creating directory(ies)");
2329
2330                         /* Create directory(ies) */
2331                         ret = run_as_mkdir_recursive(consumer->dst.trace_path,
2332                                         S_IRWXU | S_IRWXG, session->uid, session->gid);
2333                         if (ret < 0) {
2334                                 if (ret != -EEXIST) {
2335                                         ERR("Trace directory creation error");
2336                                         ret = LTTNG_ERR_FATAL;
2337                                         goto error;
2338                                 }
2339                         }
2340                         break;
2341                 case CONSUMER_DST_NET:
2342                         DBG2("Consumer output is network. Validating URIs");
2343                         /* Validate if we have both control and data path set. */
2344                         if (!consumer->dst.net.control_isset) {
2345                                 ret = LTTNG_ERR_URL_CTRL_MISS;
2346                                 goto error;
2347                         }
2348
2349                         if (!consumer->dst.net.data_isset) {
2350                                 ret = LTTNG_ERR_URL_DATA_MISS;
2351                                 goto error;
2352                         }
2353
2354                         /* Check established network session state */
2355                         if (session->net_handle == 0) {
2356                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2357                                 DBG2("Session network handle is not set on enable-consumer");
2358                                 goto error;
2359                         }
2360
2361                         if (consumer->net_seq_index == -1) {
2362                                 ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
2363                                 DBG2("Network index is not set on the consumer");
2364                                 goto error;
2365                         }
2366
2367                         break;
2368                 }
2369
2370                 /*
2371                  * @session-lock
2372                  * This is race free for now since the session lock is acquired before
2373                  * ending up in this function. No other threads can access this kernel
2374                  * session without this lock hence freeing the consumer output object
2375                  * is valid.
2376                  */
2377                 rcu_read_lock();
2378                 /* Destroy current consumer. We are about to replace it */
2379                 consumer_destroy_output(usess->consumer);
2380                 rcu_read_unlock();
2381                 usess->consumer = consumer;
2382                 usess->tmp_consumer = NULL;
2383
2384                 break;
2385         }
2386
2387         session->start_consumer = 1;
2388
2389         /* Enable it */
2390         if (consumer) {
2391                 consumer->enabled = 1;
2392                 /* Success at this point */
2393                 ret = LTTNG_OK;
2394         } else {
2395                 /* Should not really happend... */
2396                 ret = LTTNG_ERR_NO_CONSUMER;
2397         }
2398
2399 error:
2400         return ret;
2401 }
2402
2403 /*
2404  * Command LTTNG_DATA_PENDING returning 0 if the data is NOT pending meaning
2405  * ready for trace analysis (or anykind of reader) or else 1 for pending data.
2406  */
2407 int cmd_data_pending(struct ltt_session *session)
2408 {
2409         int ret;
2410         struct ltt_kernel_session *ksess = session->kernel_session;
2411         struct ltt_ust_session *usess = session->ust_session;
2412
2413         assert(session);
2414
2415         /* Session MUST be stopped to ask for data availability. */
2416         if (session->enabled) {
2417                 ret = LTTNG_ERR_SESSION_STARTED;
2418                 goto error;
2419         }
2420
2421         if (ksess && ksess->consumer) {
2422                 ret = consumer_is_data_pending(ksess->id, ksess->consumer);
2423                 if (ret == 1) {
2424                         /* Data is still being extracted for the kernel. */
2425                         goto error;
2426                 }
2427         }
2428
2429         if (usess && usess->consumer) {
2430                 ret = consumer_is_data_pending(usess->id, usess->consumer);
2431                 if (ret == 1) {
2432                         /* Data is still being extracted for the kernel. */
2433                         goto error;
2434                 }
2435         }
2436
2437         /* Data is ready to be read by a viewer */
2438         ret = 0;
2439
2440 error:
2441         return ret;
2442 }
2443
2444 /*
2445  * Init command subsystem.
2446  */
2447 void cmd_init(void)
2448 {
2449         /*
2450          * Set network sequence index to 1 for streams to match a relayd socket on
2451          * the consumer side.
2452          */
2453         uatomic_set(&relayd_net_seq_idx, 1);
2454
2455         DBG("Command subsystem initialized");
2456 }