liblttng-ust/ltt-events.c

   1 /*
   2  * ltt-events.c
   3  *
   4  * Holds LTTng per-session event registry.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _GNU_SOURCE
  24 #include <stdio.h>
  25 #include <endian.h>
  26 #include <urcu/list.h>
  27 #include <urcu/hlist.h>
  28 #include <pthread.h>
  29 #include <uuid/uuid.h>
  30 #include <errno.h>
  31 #include <sys/shm.h>
  32 #include <sys/ipc.h>
  33 #include <stdint.h>
  34 #include <stddef.h>
  35 #include <inttypes.h>
  36 #include <time.h>
  37 #include <sys/prctl.h>
  38 #include "clock.h"
  39
  40 #include <urcu-bp.h>
  41 #include <urcu/compiler.h>
  42 #include <urcu/uatomic.h>
  43 #include <urcu/arch.h>
  44
  45 #include <lttng/tracepoint.h>
  46 #include <lttng/ust-events.h>
  47
  48 #include <usterr-signal-safe.h>
  49 #include <helper.h>
  50 #include "error.h"
  51
  52 #include "tracepoint-internal.h"
  53 #include "ltt-tracer.h"
  54 #include "ltt-tracer-core.h"
  55 #include "wait.h"
  56 #include "../libringbuffer/shm.h"
  57 #include "jhash.h"
  58
  59 #define PROCNAME_LEN 17
  60
  61 /*
  62  * The sessions mutex is the centralized mutex across UST tracing
  63  * control and probe registration. All operations within this file are
  64  * called by the communication thread, under ust_lock protection.
  65  */
  66 static pthread_mutex_t sessions_mutex = PTHREAD_MUTEX_INITIALIZER;
  67
  68 void ust_lock(void)
  69 {
  70         pthread_mutex_lock(&sessions_mutex);
  71 }
  72
  73 void ust_unlock(void)
  74 {
  75         pthread_mutex_unlock(&sessions_mutex);
  76 }
  77
  78 static CDS_LIST_HEAD(sessions);
  79
  80 /*
  81  * Wildcard list, containing the active wildcards.
  82  * Protected by ust lock.
  83  */
  84 static CDS_LIST_HEAD(wildcard_list);
  85
  86 /*
  87  * Pending probes hash table, containing the registered ltt events for
  88  * which tracepoint probes are still missing. Protected by the sessions
  89  * mutex.
  90  */
  91 #define PENDING_PROBE_HASH_BITS         6
  92 #define PENDING_PROBE_HASH_SIZE         (1 << PENDING_PROBE_HASH_BITS)
  93 static struct cds_hlist_head pending_probe_table[PENDING_PROBE_HASH_SIZE];
  94
  95 struct ust_pending_probe {
  96         struct ltt_event *event;
  97         struct cds_hlist_node node;
  98         enum lttng_ust_loglevel_type loglevel_type;
  99         int loglevel;
 100         char name[];
 101 };
 102
 103 static void _ltt_event_destroy(struct ltt_event *event);
 104 static void _ltt_wildcard_destroy(struct session_wildcard *sw);
 105 static void _ltt_channel_destroy(struct ltt_channel *chan);
 106 static int _ltt_event_unregister(struct ltt_event *event);
 107 static
 108 int _ltt_event_metadata_statedump(struct ltt_session *session,
 109                                   struct ltt_channel *chan,
 110                                   struct ltt_event *event);
 111 static
 112 int _ltt_session_metadata_statedump(struct ltt_session *session);
 113
 114 int ltt_loglevel_match(const struct lttng_event_desc *desc,
 115                 enum lttng_ust_loglevel_type req_type,
 116                 int req_loglevel)
 117 {
 118         int ev_loglevel;
 119
 120         if (req_type == LTTNG_UST_LOGLEVEL_ALL)
 121                 return 1;
 122         if (!desc->loglevel)
 123                 ev_loglevel = TRACE_DEFAULT;
 124         else
 125                 ev_loglevel = *(*desc->loglevel);
 126         switch (req_type) {
 127         case LTTNG_UST_LOGLEVEL_RANGE:
 128                 if (ev_loglevel <= req_loglevel || req_loglevel == -1)
 129                         return 1;
 130                 else
 131                         return 0;
 132         case LTTNG_UST_LOGLEVEL_SINGLE:
 133                 if (ev_loglevel == req_loglevel || req_loglevel == -1)
 134                         return 1;
 135                 else
 136                         return 0;
 137         case LTTNG_UST_LOGLEVEL_ALL:
 138         default:
 139                 return 1;
 140         }
 141 }
 142
 143 /*
 144  * Return wildcard for a given event name if the event name match the
 145  * one of the wildcards.
 146  * Must be called with ust lock held.
 147  * Returns NULL if not present.
 148  */
 149 static
 150 struct wildcard_entry *match_wildcard(const struct lttng_event_desc *desc)
 151 {
 152         struct wildcard_entry *e;
 153
 154         cds_list_for_each_entry(e, &wildcard_list, list) {
 155                 /* If only contain '*' */
 156                 if (strlen(e->name) == 1)
 157                         goto possible_match;
 158                 /* Compare excluding final '*' */
 159                 if (!strncmp(desc->name, e->name, strlen(e->name) - 1))
 160                         goto possible_match;
 161                 continue;       /* goto next, no match */
 162         possible_match:
 163                 if (ltt_loglevel_match(desc,
 164                                 e->loglevel_type,
 165                                 e->loglevel)) {
 166                         return e;
 167                 }
 168                 /* no match, loop to next */
 169         }
 170         return NULL;
 171 }
 172
 173 /*
 174  * called at event creation if probe is missing.
 175  * called with session mutex held.
 176  */
 177 static
 178 int add_pending_probe(struct ltt_event *event, const char *name,
 179                 enum lttng_ust_loglevel_type loglevel_type,
 180                 int loglevel)
 181 {
 182         struct cds_hlist_head *head;
 183         struct ust_pending_probe *e;
 184         size_t name_len = strlen(name) + 1;
 185         uint32_t hash;
 186
 187         if (name_len > LTTNG_UST_SYM_NAME_LEN) {
 188                 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN);
 189                 name_len = LTTNG_UST_SYM_NAME_LEN;
 190         }
 191         hash = jhash(name, name_len - 1, 0);
 192         head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
 193         e = zmalloc(sizeof(struct ust_pending_probe) + name_len);
 194         if (!e)
 195                 return -ENOMEM;
 196         memcpy(&e->name[0], name, name_len);
 197         e->name[name_len - 1] = '\0';
 198         e->loglevel_type = loglevel_type;
 199         e->loglevel = loglevel;
 200         cds_hlist_add_head(&e->node, head);
 201         e->event = event;
 202         event->pending_probe = e;
 203         return 0;
 204 }
 205
 206 /*
 207  * remove a pending probe. called when at event teardown and when an
 208  * event is fixed (probe is loaded).
 209  * called with session mutex held.
 210  */
 211 static
 212 void remove_pending_probe(struct ust_pending_probe *e)
 213 {
 214         if (!e)
 215                 return;
 216         cds_hlist_del(&e->node);
 217         free(e);
 218 }
 219
 220 /*
 221  * Called at library load: connect the probe on the events pending on
 222  * probe load.
 223  * called with session mutex held.
 224  */
 225 int pending_probe_fix_events(const struct lttng_event_desc *desc)
 226 {
 227         struct cds_hlist_head *head;
 228         struct cds_hlist_node *node, *p;
 229         struct ust_pending_probe *e;
 230         const char *name = desc->name;
 231         int ret = 0;
 232         struct lttng_ust_event event_param;
 233         size_t name_len = strlen(name) + 1;
 234         uint32_t hash;
 235
 236         /* Wildcard */
 237         {
 238                 struct wildcard_entry *wildcard;
 239
 240                 wildcard = match_wildcard(desc);
 241                 if (strcmp(desc->name, "lttng_ust:metadata") && wildcard) {
 242                         struct session_wildcard *sw;
 243
 244                         cds_list_for_each_entry(sw, &wildcard->session_list,
 245                                         session_list) {
 246                                 struct ltt_event *ev;
 247                                 int ret;
 248
 249                                 memcpy(&event_param, &sw->event_param,
 250                                                 sizeof(event_param));
 251                                 memcpy(event_param.name,
 252                                         desc->name,
 253                                         sizeof(event_param.name));
 254                                 /* create event */
 255                                 ret = ltt_event_create(sw->chan,
 256                                         &event_param, NULL,
 257                                         &ev);
 258                                 if (ret) {
 259                                         DBG("Error creating event");
 260                                         continue;
 261                                 }
 262                                 cds_list_add(&ev->wildcard_list,
 263                                         &sw->events);
 264                         }
 265                 }
 266         }
 267
 268         if (name_len > LTTNG_UST_SYM_NAME_LEN) {
 269                 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN);
 270                 name_len = LTTNG_UST_SYM_NAME_LEN;
 271         }
 272         hash = jhash(name, name_len - 1, 0);
 273         head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
 274         cds_hlist_for_each_entry_safe(e, node, p, head, node) {
 275                 struct ltt_event *event;
 276                 struct ltt_channel *chan;
 277
 278                 if (!ltt_loglevel_match(desc,
 279                                 e->loglevel_type,
 280                                 e->loglevel)) {
 281                         continue;
 282                 }
 283                 if (strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) {
 284                         continue;
 285                 }
 286                 event = e->event;
 287                 chan = event->chan;
 288                 assert(!event->desc);
 289                 event->desc = desc;
 290                 event->pending_probe = NULL;
 291                 remove_pending_probe(e);
 292                 ret |= __tracepoint_probe_register(name,
 293                                 event->desc->probe_callback,
 294                                 event, event->desc->signature);
 295                 if (ret)
 296                         continue;
 297                 event->id = chan->free_event_id++;
 298                 ret |= _ltt_event_metadata_statedump(chan->session, chan,
 299                                 event);
 300         }
 301         return ret;
 302 }
 303
 304 void synchronize_trace(void)
 305 {
 306         synchronize_rcu();
 307 }
 308
 309 struct ltt_session *ltt_session_create(void)
 310 {
 311         struct ltt_session *session;
 312
 313         session = zmalloc(sizeof(struct ltt_session));
 314         if (!session)
 315                 return NULL;
 316         CDS_INIT_LIST_HEAD(&session->chan);
 317         CDS_INIT_LIST_HEAD(&session->events);
 318         CDS_INIT_LIST_HEAD(&session->wildcards);
 319         uuid_generate(session->uuid);
 320         cds_list_add(&session->list, &sessions);
 321         return session;
 322 }
 323
 324 void ltt_session_destroy(struct ltt_session *session)
 325 {
 326         struct ltt_channel *chan, *tmpchan;
 327         struct ltt_event *event, *tmpevent;
 328         struct session_wildcard *wildcard, *tmpwildcard;
 329         int ret;
 330
 331         CMM_ACCESS_ONCE(session->active) = 0;
 332         cds_list_for_each_entry(event, &session->events, list) {
 333                 ret = _ltt_event_unregister(event);
 334                 WARN_ON(ret);
 335         }
 336         synchronize_trace();    /* Wait for in-flight events to complete */
 337         cds_list_for_each_entry_safe(wildcard, tmpwildcard, &session->wildcards, list)
 338                 _ltt_wildcard_destroy(wildcard);
 339         cds_list_for_each_entry_safe(event, tmpevent, &session->events, list)
 340                 _ltt_event_destroy(event);
 341         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
 342                 _ltt_channel_destroy(chan);
 343         cds_list_del(&session->list);
 344         free(session);
 345 }
 346
 347 int ltt_session_enable(struct ltt_session *session)
 348 {
 349         int ret = 0;
 350         struct ltt_channel *chan;
 351
 352         if (session->active) {
 353                 ret = -EBUSY;
 354                 goto end;
 355         }
 356
 357         /*
 358          * Snapshot the number of events per channel to know the type of header
 359          * we need to use.
 360          */
 361         cds_list_for_each_entry(chan, &session->chan, list) {
 362                 if (chan->header_type)
 363                         continue;               /* don't change it if session stop/restart */
 364                 if (chan->free_event_id < 31)
 365                         chan->header_type = 1;  /* compact */
 366                 else
 367                         chan->header_type = 2;  /* large */
 368         }
 369
 370         CMM_ACCESS_ONCE(session->active) = 1;
 371         CMM_ACCESS_ONCE(session->been_active) = 1;
 372         ret = _ltt_session_metadata_statedump(session);
 373         if (ret)
 374                 CMM_ACCESS_ONCE(session->active) = 0;
 375 end:
 376         return ret;
 377 }
 378
 379 int ltt_session_disable(struct ltt_session *session)
 380 {
 381         int ret = 0;
 382
 383         if (!session->active) {
 384                 ret = -EBUSY;
 385                 goto end;
 386         }
 387         CMM_ACCESS_ONCE(session->active) = 0;
 388 end:
 389         return ret;
 390 }
 391
 392 int ltt_channel_enable(struct ltt_channel *channel)
 393 {
 394         int old;
 395
 396         if (channel == channel->session->metadata)
 397                 return -EPERM;
 398         old = uatomic_xchg(&channel->enabled, 1);
 399         if (old)
 400                 return -EEXIST;
 401         return 0;
 402 }
 403
 404 int ltt_channel_disable(struct ltt_channel *channel)
 405 {
 406         int old;
 407
 408         if (channel == channel->session->metadata)
 409                 return -EPERM;
 410         old = uatomic_xchg(&channel->enabled, 0);
 411         if (!old)
 412                 return -EEXIST;
 413         return 0;
 414 }
 415
 416 int ltt_event_enable(struct ltt_event *event)
 417 {
 418         int old;
 419
 420         if (event->chan == event->chan->session->metadata)
 421                 return -EPERM;
 422         old = uatomic_xchg(&event->enabled, 1);
 423         if (old)
 424                 return -EEXIST;
 425         return 0;
 426 }
 427
 428 int ltt_event_disable(struct ltt_event *event)
 429 {
 430         int old;
 431
 432         if (event->chan == event->chan->session->metadata)
 433                 return -EPERM;
 434         old = uatomic_xchg(&event->enabled, 0);
 435         if (!old)
 436                 return -EEXIST;
 437         return 0;
 438 }
 439
 440 struct ltt_channel *ltt_channel_create(struct ltt_session *session,
 441                                        const char *transport_name,
 442                                        void *buf_addr,
 443                                        size_t subbuf_size, size_t num_subbuf,
 444                                        unsigned int switch_timer_interval,
 445                                        unsigned int read_timer_interval,
 446                                        int **shm_fd, int **wait_fd,
 447                                        uint64_t **memory_map_size,
 448                                        struct ltt_channel *chan_priv_init)
 449 {
 450         struct ltt_channel *chan = NULL;
 451         struct ltt_transport *transport;
 452
 453         if (session->been_active)
 454                 goto active;    /* Refuse to add channel to active session */
 455         transport = ltt_transport_find(transport_name);
 456         if (!transport) {
 457                 DBG("LTTng transport %s not found\n",
 458                        transport_name);
 459                 goto notransport;
 460         }
 461         chan_priv_init->id = session->free_chan_id++;
 462         chan_priv_init->session = session;
 463         /*
 464          * Note: the channel creation op already writes into the packet
 465          * headers. Therefore the "chan" information used as input
 466          * should be already accessible.
 467          */
 468         chan = transport->ops.channel_create(transport_name, buf_addr,
 469                         subbuf_size, num_subbuf, switch_timer_interval,
 470                         read_timer_interval, shm_fd, wait_fd,
 471                         memory_map_size, chan_priv_init);
 472         if (!chan)
 473                 goto create_error;
 474         chan->enabled = 1;
 475         chan->ops = &transport->ops;
 476         cds_list_add(&chan->list, &session->chan);
 477         return chan;
 478
 479 create_error:
 480 notransport:
 481 active:
 482         return NULL;
 483 }
 484
 485 /*
 486  * Only used internally at session destruction.
 487  */
 488 static
 489 void _ltt_channel_destroy(struct ltt_channel *chan)
 490 {
 491         cds_list_del(&chan->list);
 492         lttng_destroy_context(chan->ctx);
 493         chan->ops->channel_destroy(chan);
 494 }
 495
 496 /*
 497  * Supports event creation while tracing session is active.
 498  */
 499 int ltt_event_create(struct ltt_channel *chan,
 500                 struct lttng_ust_event *event_param,
 501                 void (*filter)(struct ltt_event *event),
 502                 struct ltt_event **_event)
 503 {
 504         const struct lttng_event_desc *desc = NULL;     /* silence gcc */
 505         struct ltt_event *event;
 506         int ret = 0;
 507
 508         if (chan->used_event_id == -1U) {
 509                 ret = -ENOMEM;
 510                 goto full;
 511         }
 512         /*
 513          * This is O(n^2) (for each event, the loop is called at event
 514          * creation). Might require a hash if we have lots of events.
 515          */
 516         cds_list_for_each_entry(event, &chan->session->events, list) {
 517                 if (event->desc && !strncmp(event->desc->name,
 518                                 event_param->name,
 519                                 LTTNG_UST_SYM_NAME_LEN - 1)) {
 520                         ret = -EEXIST;
 521                         goto exist;
 522                 }
 523         }
 524
 525         /*
 526          * Check if loglevel match. Refuse to connect event if not.
 527          */
 528         if (event_param->instrumentation == LTTNG_UST_TRACEPOINT) {
 529                 desc = ltt_event_get(event_param->name);
 530                 if (desc) {
 531                         if (!ltt_loglevel_match(desc,
 532                                         event_param->loglevel_type,
 533                                         event_param->loglevel)) {
 534                                 ret = -EPERM;
 535                                 goto no_loglevel_match;
 536                         }
 537                 }
 538                 /*
 539                  * If descriptor is not there, it will be added to
 540                  * pending probes.
 541                  */
 542         }
 543         event = zmalloc(sizeof(struct ltt_event));
 544         if (!event) {
 545                 ret = -ENOMEM;
 546                 goto cache_error;
 547         }
 548         event->chan = chan;
 549         event->filter = filter;
 550         /*
 551          * used_event_id counts the maximum number of event IDs that can
 552          * register if all probes register.
 553          */
 554         chan->used_event_id++;
 555         event->enabled = 1;
 556         event->instrumentation = event_param->instrumentation;
 557         /* Populate ltt_event structure before tracepoint registration. */
 558         cmm_smp_wmb();
 559         switch (event_param->instrumentation) {
 560         case LTTNG_UST_TRACEPOINT:
 561                 event->desc = desc;
 562                 if (event->desc) {
 563                         ret = __tracepoint_probe_register(event_param->name,
 564                                         event->desc->probe_callback,
 565                                         event, event->desc->signature);
 566                         if (ret)
 567                                 goto register_error;
 568                         event->id = chan->free_event_id++;
 569                 } else {
 570                         /*
 571                          * If the probe is not present, event->desc stays NULL,
 572                          * waiting for the probe to register, and the event->id
 573                          * stays unallocated.
 574                          */
 575                         ret = add_pending_probe(event, event_param->name,
 576                                         event_param->loglevel_type,
 577                                         event_param->loglevel);
 578                         if (ret)
 579                                 goto add_pending_error;
 580                 }
 581                 break;
 582         default:
 583                 WARN_ON_ONCE(1);
 584         }
 585         if (event->desc) {
 586                 ret = _ltt_event_metadata_statedump(chan->session, chan, event);
 587                 if (ret)
 588                         goto statedump_error;
 589         }
 590         cds_list_add(&event->list, &chan->session->events);
 591         *_event = event;
 592         return 0;
 593
 594 statedump_error:
 595         if (event->desc) {
 596                 WARN_ON_ONCE(__tracepoint_probe_unregister(event_param->name,
 597                                         event->desc->probe_callback,
 598                                         event));
 599                 ltt_event_put(event->desc);
 600         }
 601 add_pending_error:
 602 register_error:
 603         free(event);
 604 cache_error:
 605 no_loglevel_match:
 606 exist:
 607 full:
 608         return ret;
 609 }
 610
 611 /*
 612  * Only used internally at session destruction.
 613  */
 614 int _ltt_event_unregister(struct ltt_event *event)
 615 {
 616         int ret = -EINVAL;
 617
 618         switch (event->instrumentation) {
 619         case LTTNG_UST_TRACEPOINT:
 620                 if (event->desc) {
 621                         ret = __tracepoint_probe_unregister(event->desc->name,
 622                                                           event->desc->probe_callback,
 623                                                           event);
 624                         if (ret)
 625                                 return ret;
 626                 } else {
 627                         remove_pending_probe(event->pending_probe);
 628                         ret = 0;
 629                 }
 630                 break;
 631         default:
 632                 WARN_ON_ONCE(1);
 633         }
 634         return ret;
 635 }
 636
 637 /*
 638  * Only used internally at session destruction.
 639  */
 640 static
 641 void _ltt_event_destroy(struct ltt_event *event)
 642 {
 643         switch (event->instrumentation) {
 644         case LTTNG_UST_TRACEPOINT:
 645                 if (event->desc) {
 646                         ltt_event_put(event->desc);
 647                 }
 648                 break;
 649         default:
 650                 WARN_ON_ONCE(1);
 651         }
 652         cds_list_del(&event->list);
 653         lttng_destroy_context(event->ctx);
 654         free(event);
 655 }
 656
 657 /*
 658  * We have exclusive access to our metadata buffer (protected by the
 659  * ust_lock), so we can do racy operations such as looking for
 660  * remaining space left in packet and write, since mutual exclusion
 661  * protects us from concurrent writes.
 662  */
 663 int lttng_metadata_printf(struct ltt_session *session,
 664                           const char *fmt, ...)
 665 {
 666         struct lttng_ust_lib_ring_buffer_ctx ctx;
 667         struct ltt_channel *chan = session->metadata;
 668         char *str = NULL;
 669         int ret = 0, waitret;
 670         size_t len, reserve_len, pos;
 671         va_list ap;
 672
 673         WARN_ON_ONCE(!CMM_ACCESS_ONCE(session->active));
 674
 675         va_start(ap, fmt);
 676         ret = vasprintf(&str, fmt, ap);
 677         va_end(ap);
 678         if (ret < 0)
 679                 return -ENOMEM;
 680
 681         len = strlen(str);
 682         pos = 0;
 683
 684         for (pos = 0; pos < len; pos += reserve_len) {
 685                 reserve_len = min_t(size_t,
 686                                 chan->ops->packet_avail_size(chan->chan, chan->handle),
 687                                 len - pos);
 688                 lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len,
 689                                          sizeof(char), -1, chan->handle);
 690                 /*
 691                  * We don't care about metadata buffer's records lost
 692                  * count, because we always retry here. Report error if
 693                  * we need to bail out after timeout or being
 694                  * interrupted.
 695                  */
 696                 waitret = wait_cond_interruptible_timeout(
 697                         ({
 698                                 ret = chan->ops->event_reserve(&ctx, 0);
 699                                 ret != -ENOBUFS || !ret;
 700                         }),
 701                         LTTNG_METADATA_TIMEOUT_MSEC);
 702                 if (waitret == -ETIMEDOUT || waitret == -EINTR || ret) {
 703                         DBG("LTTng: Failure to write metadata to buffers (%s)\n",
 704                                 waitret == -EINTR ? "interrupted" :
 705                                         (ret == -ENOBUFS ? "timeout" : "I/O error"));
 706                         if (waitret == -EINTR)
 707                                 ret = waitret;
 708                         goto end;
 709                 }
 710                 chan->ops->event_write(&ctx, &str[pos], reserve_len);
 711                 chan->ops->event_commit(&ctx);
 712         }
 713 end:
 714         free(str);
 715         return ret;
 716 }
 717
 718 static
 719 int _ltt_field_statedump(struct ltt_session *session,
 720                          const struct lttng_event_field *field)
 721 {
 722         int ret = 0;
 723
 724         switch (field->type.atype) {
 725         case atype_integer:
 726                 ret = lttng_metadata_printf(session,
 727                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
 728                         field->type.u.basic.integer.size,
 729                         field->type.u.basic.integer.alignment,
 730                         field->type.u.basic.integer.signedness,
 731                         (field->type.u.basic.integer.encoding == lttng_encode_none)
 732                                 ? "none"
 733                                 : (field->type.u.basic.integer.encoding == lttng_encode_UTF8)
 734                                         ? "UTF8"
 735                                         : "ASCII",
 736                         field->type.u.basic.integer.base,
 737 #if (BYTE_ORDER == BIG_ENDIAN)
 738                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 739 #else
 740                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 741 #endif
 742                         field->name);
 743                 break;
 744         case atype_float:
 745                 ret = lttng_metadata_printf(session,
 746                         "               floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
 747                         field->type.u.basic._float.exp_dig,
 748                         field->type.u.basic._float.mant_dig,
 749                         field->type.u.basic._float.alignment,
 750 #if (BYTE_ORDER == BIG_ENDIAN)
 751                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 752 #else
 753                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 754 #endif
 755                         field->name);
 756                 break;
 757         case atype_enum:
 758                 ret = lttng_metadata_printf(session,
 759                         "               %s %s;\n",
 760                         field->type.u.basic.enumeration.name,
 761                         field->name);
 762                 break;
 763         case atype_array:
 764         {
 765                 const struct lttng_basic_type *elem_type;
 766
 767                 elem_type = &field->type.u.array.elem_type;
 768                 ret = lttng_metadata_printf(session,
 769                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
 770                         elem_type->u.basic.integer.size,
 771                         elem_type->u.basic.integer.alignment,
 772                         elem_type->u.basic.integer.signedness,
 773                         (elem_type->u.basic.integer.encoding == lttng_encode_none)
 774                                 ? "none"
 775                                 : (elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
 776                                         ? "UTF8"
 777                                         : "ASCII",
 778                         elem_type->u.basic.integer.base,
 779 #if (BYTE_ORDER == BIG_ENDIAN)
 780                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 781 #else
 782                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 783 #endif
 784                         field->name, field->type.u.array.length);
 785                 break;
 786         }
 787         case atype_sequence:
 788         {
 789                 const struct lttng_basic_type *elem_type;
 790                 const struct lttng_basic_type *length_type;
 791
 792                 elem_type = &field->type.u.sequence.elem_type;
 793                 length_type = &field->type.u.sequence.length_type;
 794                 ret = lttng_metadata_printf(session,
 795                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
 796                         length_type->u.basic.integer.size,
 797                         (unsigned int) length_type->u.basic.integer.alignment,
 798                         length_type->u.basic.integer.signedness,
 799                         (length_type->u.basic.integer.encoding == lttng_encode_none)
 800                                 ? "none"
 801                                 : ((length_type->u.basic.integer.encoding == lttng_encode_UTF8)
 802                                         ? "UTF8"
 803                                         : "ASCII"),
 804                         length_type->u.basic.integer.base,
 805 #if (BYTE_ORDER == BIG_ENDIAN)
 806                         length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 807 #else
 808                         length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 809 #endif
 810                         field->name);
 811                 if (ret)
 812                         return ret;
 813
 814                 ret = lttng_metadata_printf(session,
 815                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
 816                         elem_type->u.basic.integer.size,
 817                         (unsigned int) elem_type->u.basic.integer.alignment,
 818                         elem_type->u.basic.integer.signedness,
 819                         (elem_type->u.basic.integer.encoding == lttng_encode_none)
 820                                 ? "none"
 821                                 : ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
 822                                         ? "UTF8"
 823                                         : "ASCII"),
 824                         elem_type->u.basic.integer.base,
 825 #if (BYTE_ORDER == BIG_ENDIAN)
 826                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 827 #else
 828                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 829 #endif
 830                         field->name,
 831                         field->name);
 832                 break;
 833         }
 834
 835         case atype_string:
 836                 /* Default encoding is UTF8 */
 837                 ret = lttng_metadata_printf(session,
 838                         "               string%s _%s;\n",
 839                         field->type.u.basic.string.encoding == lttng_encode_ASCII ?
 840                                 " { encoding = ASCII; }" : "",
 841                         field->name);
 842                 break;
 843         default:
 844                 WARN_ON_ONCE(1);
 845                 return -EINVAL;
 846         }
 847         return ret;
 848 }
 849
 850 static
 851 int _ltt_context_metadata_statedump(struct ltt_session *session,
 852                                     struct lttng_ctx *ctx)
 853 {
 854         int ret = 0;
 855         int i;
 856
 857         if (!ctx)
 858                 return 0;
 859         for (i = 0; i < ctx->nr_fields; i++) {
 860                 const struct lttng_ctx_field *field = &ctx->fields[i];
 861
 862                 ret = _ltt_field_statedump(session, &field->event_field);
 863                 if (ret)
 864                         return ret;
 865         }
 866         return ret;
 867 }
 868
 869 static
 870 int _ltt_fields_metadata_statedump(struct ltt_session *session,
 871                                    struct ltt_event *event)
 872 {
 873         const struct lttng_event_desc *desc = event->desc;
 874         int ret = 0;
 875         int i;
 876
 877         for (i = 0; i < desc->nr_fields; i++) {
 878                 const struct lttng_event_field *field = &desc->fields[i];
 879
 880                 ret = _ltt_field_statedump(session, field);
 881                 if (ret)
 882                         return ret;
 883         }
 884         return ret;
 885 }
 886
 887 static
 888 int _ltt_event_metadata_statedump(struct ltt_session *session,
 889                                   struct ltt_channel *chan,
 890                                   struct ltt_event *event)
 891 {
 892         int ret = 0;
 893         int loglevel = TRACE_DEFAULT;
 894
 895         if (event->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
 896                 return 0;
 897         if (chan == session->metadata)
 898                 return 0;
 899         /*
 900          * Don't print events for which probe load is pending.
 901          */
 902         if (!event->desc)
 903                 return 0;
 904
 905         ret = lttng_metadata_printf(session,
 906                 "event {\n"
 907                 "       name = \"%s\";\n"
 908                 "       id = %u;\n"
 909                 "       stream_id = %u;\n",
 910                 event->desc->name,
 911                 event->id,
 912                 event->chan->id);
 913         if (ret)
 914                 goto end;
 915
 916         if (event->desc->loglevel)
 917                 loglevel = *(*event->desc->loglevel);
 918
 919         ret = lttng_metadata_printf(session,
 920                 "       loglevel = %d;\n",
 921                 loglevel);
 922         if (ret)
 923                 goto end;
 924
 925         if (event->ctx) {
 926                 ret = lttng_metadata_printf(session,
 927                         "       context := struct {\n");
 928                 if (ret)
 929                         goto end;
 930         }
 931         ret = _ltt_context_metadata_statedump(session, event->ctx);
 932         if (ret)
 933                 goto end;
 934         if (event->ctx) {
 935                 ret = lttng_metadata_printf(session,
 936                         "       };\n");
 937                 if (ret)
 938                         goto end;
 939         }
 940
 941         ret = lttng_metadata_printf(session,
 942                 "       fields := struct {\n"
 943                 );
 944         if (ret)
 945                 goto end;
 946
 947         ret = _ltt_fields_metadata_statedump(session, event);
 948         if (ret)
 949                 goto end;
 950
 951         /*
 952          * LTTng space reservation can only reserve multiples of the
 953          * byte size.
 954          */
 955         ret = lttng_metadata_printf(session,
 956                 "       };\n"
 957                 "};\n\n");
 958         if (ret)
 959                 goto end;
 960
 961         event->metadata_dumped = 1;
 962 end:
 963         return ret;
 964
 965 }
 966
 967 static
 968 int _ltt_channel_metadata_statedump(struct ltt_session *session,
 969                                     struct ltt_channel *chan)
 970 {
 971         int ret = 0;
 972
 973         if (chan->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
 974                 return 0;
 975         if (chan == session->metadata)
 976                 return 0;
 977
 978         WARN_ON_ONCE(!chan->header_type);
 979         ret = lttng_metadata_printf(session,
 980                 "stream {\n"
 981                 "       id = %u;\n"
 982                 "       event.header := %s;\n"
 983                 "       packet.context := struct packet_context;\n",
 984                 chan->id,
 985                 chan->header_type == 1 ? "struct event_header_compact" :
 986                         "struct event_header_large");
 987         if (ret)
 988                 goto end;
 989
 990         if (chan->ctx) {
 991                 ret = lttng_metadata_printf(session,
 992                         "       event.context := struct {\n");
 993                 if (ret)
 994                         goto end;
 995         }
 996         ret = _ltt_context_metadata_statedump(session, chan->ctx);
 997         if (ret)
 998                 goto end;
 999         if (chan->ctx) {
1000                 ret = lttng_metadata_printf(session,
1001                         "       };\n");
1002                 if (ret)
1003                         goto end;
1004         }
1005
1006         ret = lttng_metadata_printf(session,
1007                 "};\n\n");
1008
1009         chan->metadata_dumped = 1;
1010 end:
1011         return ret;
1012 }
1013
1014 static
1015 int _ltt_stream_packet_context_declare(struct ltt_session *session)
1016 {
1017         return lttng_metadata_printf(session,
1018                 "struct packet_context {\n"
1019                 "       uint64_clock_monotonic_t timestamp_begin;\n"
1020                 "       uint64_clock_monotonic_t timestamp_end;\n"
1021                 "       uint32_t events_discarded;\n"
1022                 "       uint32_t content_size;\n"
1023                 "       uint32_t packet_size;\n"
1024                 "       uint32_t cpu_id;\n"
1025                 "};\n\n"
1026                 );
1027 }
1028
1029 /*
1030  * Compact header:
1031  * id: range: 0 - 30.
1032  * id 31 is reserved to indicate an extended header.
1033  *
1034  * Large header:
1035  * id: range: 0 - 65534.
1036  * id 65535 is reserved to indicate an extended header.
1037  */
1038 static
1039 int _ltt_event_header_declare(struct ltt_session *session)
1040 {
1041         return lttng_metadata_printf(session,
1042         "struct event_header_compact {\n"
1043         "       enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
1044         "       variant <id> {\n"
1045         "               struct {\n"
1046         "                       uint27_clock_monotonic_t timestamp;\n"
1047         "               } compact;\n"
1048         "               struct {\n"
1049         "                       uint32_t id;\n"
1050         "                       uint64_clock_monotonic_t timestamp;\n"
1051         "               } extended;\n"
1052         "       } v;\n"
1053         "} align(%u);\n"
1054         "\n"
1055         "struct event_header_large {\n"
1056         "       enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
1057         "       variant <id> {\n"
1058         "               struct {\n"
1059         "                       uint32_clock_monotonic_t timestamp;\n"
1060         "               } compact;\n"
1061         "               struct {\n"
1062         "                       uint32_t id;\n"
1063         "                       uint64_clock_monotonic_t timestamp;\n"
1064         "               } extended;\n"
1065         "       } v;\n"
1066         "} align(%u);\n\n",
1067         lttng_alignof(uint32_t) * CHAR_BIT,
1068         lttng_alignof(uint16_t) * CHAR_BIT
1069         );
1070 }
1071
1072 /*
1073  * Approximation of NTP time of day to clock monotonic correlation,
1074  * taken at start of trace.
1075  * Yes, this is only an approximation. Yes, we can (and will) do better
1076  * in future versions.
1077  */
1078 static
1079 uint64_t measure_clock_offset(void)
1080 {
1081         uint64_t offset, monotonic[2], realtime;
1082         struct timespec rts = { 0, 0 };
1083         int ret;
1084
1085         monotonic[0] = trace_clock_read64();
1086         ret = clock_gettime(CLOCK_REALTIME, &rts);
1087         if (ret < 0)
1088                 return 0;
1089         monotonic[1] = trace_clock_read64();
1090         offset = (monotonic[0] + monotonic[1]) >> 1;
1091         realtime = (uint64_t) rts.tv_sec * 1000000000ULL;
1092         realtime += rts.tv_nsec;
1093         offset = realtime - offset;
1094         return offset;
1095 }
1096
1097 /*
1098  * Output metadata into this session's metadata buffers.
1099  */
1100 static
1101 int _ltt_session_metadata_statedump(struct ltt_session *session)
1102 {
1103         unsigned char *uuid_c = session->uuid;
1104         char uuid_s[37], clock_uuid_s[CLOCK_UUID_LEN];
1105         struct ltt_channel *chan;
1106         struct ltt_event *event;
1107         int ret = 0;
1108         char procname[PROCNAME_LEN] = "";
1109
1110         if (!CMM_ACCESS_ONCE(session->active))
1111                 return 0;
1112         if (session->metadata_dumped)
1113                 goto skip_session;
1114         if (!session->metadata) {
1115                 DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
1116                 return -EPERM;
1117         }
1118
1119         snprintf(uuid_s, sizeof(uuid_s),
1120                 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
1121                 uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
1122                 uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
1123                 uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
1124                 uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
1125
1126         ret = lttng_metadata_printf(session,
1127                 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
1128                 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
1129                 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
1130                 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
1131                 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
1132                 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
1133                 "\n"
1134                 "trace {\n"
1135                 "       major = %u;\n"
1136                 "       minor = %u;\n"
1137                 "       uuid = \"%s\";\n"
1138                 "       byte_order = %s;\n"
1139                 "       packet.header := struct {\n"
1140                 "               uint32_t magic;\n"
1141                 "               uint8_t  uuid[16];\n"
1142                 "               uint32_t stream_id;\n"
1143                 "       };\n"
1144                 "};\n\n",
1145                 lttng_alignof(uint8_t) * CHAR_BIT,
1146                 lttng_alignof(uint16_t) * CHAR_BIT,
1147                 lttng_alignof(uint32_t) * CHAR_BIT,
1148                 lttng_alignof(uint64_t) * CHAR_BIT,
1149                 CTF_SPEC_MAJOR,
1150                 CTF_SPEC_MINOR,
1151                 uuid_s,
1152 #if (BYTE_ORDER == BIG_ENDIAN)
1153                 "be"
1154 #else
1155                 "le"
1156 #endif
1157                 );
1158         if (ret)
1159                 goto end;
1160
1161         /* ignore error, just use empty string if error. */
1162         (void) prctl(PR_GET_NAME, (unsigned long) procname, 0, 0, 0);
1163         procname[PROCNAME_LEN - 1] = '\0';
1164         ret = lttng_metadata_printf(session,
1165                 "env {\n"
1166                 "       vpid = %d;\n"
1167                 "       procname = \"%s\";\n"
1168                 "       domain = \"ust\";\n"
1169                 "       tracer_name = \"lttng-ust\";\n"
1170                 "       tracer_major = %u;\n"
1171                 "       tracer_minor = %u;\n"
1172                 "       tracer_patchlevel = %u;\n"
1173                 "};\n\n",
1174                 (int) getpid(),
1175                 procname,
1176                 LTTNG_UST_MAJOR_VERSION,
1177                 LTTNG_UST_MINOR_VERSION,
1178                 LTTNG_UST_PATCHLEVEL_VERSION
1179                 );
1180         if (ret)
1181                 goto end;
1182
1183         ret = lttng_metadata_printf(session,
1184                 "clock {\n"
1185                 "       name = %s;\n",
1186                 "monotonic"
1187                 );
1188         if (ret)
1189                 goto end;
1190
1191         if (!trace_clock_uuid(clock_uuid_s)) {
1192                 ret = lttng_metadata_printf(session,
1193                         "       uuid = \"%s\";\n",
1194                         clock_uuid_s
1195                         );
1196                 if (ret)
1197                         goto end;
1198         }
1199
1200         ret = lttng_metadata_printf(session,
1201                 "       description = \"Monotonic Clock\";\n"
1202                 "       freq = %" PRIu64 "; /* Frequency, in Hz */\n"
1203                 "       /* clock value offset from Epoch is: offset * (1/freq) */\n"
1204                 "       offset = %" PRIu64 ";\n"
1205                 "};\n\n",
1206                 trace_clock_freq(),
1207                 measure_clock_offset()
1208                 );
1209         if (ret)
1210                 goto end;
1211
1212         ret = lttng_metadata_printf(session,
1213                 "typealias integer {\n"
1214                 "       size = 27; align = 1; signed = false;\n"
1215                 "       map = clock.monotonic.value;\n"
1216                 "} := uint27_clock_monotonic_t;\n"
1217                 "\n"
1218                 "typealias integer {\n"
1219                 "       size = 32; align = %u; signed = false;\n"
1220                 "       map = clock.monotonic.value;\n"
1221                 "} := uint32_clock_monotonic_t;\n"
1222                 "\n"
1223                 "typealias integer {\n"
1224                 "       size = 64; align = %u; signed = false;\n"
1225                 "       map = clock.monotonic.value;\n"
1226                 "} := uint64_clock_monotonic_t;\n\n",
1227                 lttng_alignof(uint32_t) * CHAR_BIT,
1228                 lttng_alignof(uint64_t) * CHAR_BIT
1229                 );
1230         if (ret)
1231                 goto end;
1232
1233         ret = _ltt_stream_packet_context_declare(session);
1234         if (ret)
1235                 goto end;
1236
1237         ret = _ltt_event_header_declare(session);
1238         if (ret)
1239                 goto end;
1240
1241 skip_session:
1242         cds_list_for_each_entry(chan, &session->chan, list) {
1243                 ret = _ltt_channel_metadata_statedump(session, chan);
1244                 if (ret)
1245                         goto end;
1246         }
1247
1248         cds_list_for_each_entry(event, &session->events, list) {
1249                 ret = _ltt_event_metadata_statedump(session, event->chan, event);
1250                 if (ret)
1251                         goto end;
1252         }
1253         session->metadata_dumped = 1;
1254 end:
1255         return ret;
1256 }
1257
1258 void lttng_ust_events_exit(void)
1259 {
1260         struct ltt_session *session, *tmpsession;
1261
1262         cds_list_for_each_entry_safe(session, tmpsession, &sessions, list)
1263                 ltt_session_destroy(session);
1264 }
1265
1266 /* WILDCARDS */
1267
1268 static
1269 int wildcard_same_loglevel(struct wildcard_entry *e,
1270         enum lttng_ust_loglevel_type loglevel_type,
1271         int loglevel)
1272 {
1273         if (e->loglevel_type == loglevel_type && e->loglevel == loglevel)
1274                 return 1;
1275         else
1276                 return 0;
1277 }
1278
1279 #if 0
1280 static
1281 int wildcard_is_within(struct wildcard_entry *e,
1282         enum lttng_ust_loglevel_type loglevel_type,
1283         int loglevel)
1284 {
1285         if (e->loglevel_type == LTTNG_UST_LOGLEVEL_ALL
1286                         || e->loglevel == -1)
1287                 return 1;
1288         switch (e->loglevel_type) {
1289         case LTTNG_UST_LOGLEVEL_RANGE:
1290                 switch (loglevel_type) {
1291                 case LTTNG_UST_LOGLEVEL_RANGE:
1292                         if (e->loglevel >= loglevel)
1293                                 return 1;
1294                         else
1295                                 return 0;
1296                 case LTTNG_UST_LOGLEVEL_SINGLE:
1297                         if (e->loglevel <= 0 && loglevel == 0)
1298                                 return 1;
1299                         else
1300                                 return 0;
1301                 }
1302         case LTTNG_UST_LOGLEVEL_SINGLE:
1303                 switch (loglevel_type) {
1304                 case LTTNG_UST_LOGLEVEL_RANGE:
1305                         if (loglevel <= 0)
1306                                 return 1;
1307                         else
1308                                 return 0;
1309                 case LTTNG_UST_LOGLEVEL_SINGLE:
1310                         if (e->loglevel == loglevel)
1311                                 return 1;
1312                         else
1313                                 return 0;
1314                 }
1315         }
1316 }
1317 #endif
1318
1319 /*
1320  * Add the wildcard to the wildcard list. Must be called with
1321  * ust lock held.
1322  */
1323 static
1324 struct session_wildcard *add_wildcard(struct ltt_channel *chan,
1325         struct lttng_ust_event *event_param)
1326 {
1327         struct wildcard_entry *e;
1328         struct session_wildcard *sw;
1329         size_t name_len = strlen(event_param->name) + 1;
1330         int found = 0;
1331
1332         /*
1333          * Try to find global wildcard entry. Given that this is shared
1334          * across all sessions, we need to check for exact loglevel
1335          * match, not just whether contained within the existing ones.
1336          */
1337         cds_list_for_each_entry(e, &wildcard_list, list) {
1338                 if (!strncmp(event_param->name, e->name,
1339                                 LTTNG_UST_SYM_NAME_LEN - 1)) {
1340                         if (wildcard_same_loglevel(e,
1341                                         event_param->loglevel_type,
1342                                         event_param->loglevel)) {
1343                                 found = 1;
1344                                 break;
1345                         }
1346                 }
1347         }
1348
1349         if (!found) {
1350                 /*
1351                  * Create global wildcard entry if not found. Using
1352                  * zmalloc here to allocate a variable length element.
1353                  * Could cause some memory fragmentation if overused.
1354                  */
1355                 e = zmalloc(sizeof(struct wildcard_entry) + name_len);
1356                 if (!e)
1357                         return ERR_PTR(-ENOMEM);
1358                 memcpy(&e->name[0], event_param->name, name_len);
1359                 e->loglevel_type = event_param->loglevel_type;
1360                 e->loglevel = event_param->loglevel;
1361                 cds_list_add(&e->list, &wildcard_list);
1362                 CDS_INIT_LIST_HEAD(&e->session_list);
1363         }
1364
1365         /* session wildcard */
1366         cds_list_for_each_entry(sw, &e->session_list, session_list) {
1367                 if (chan == sw->chan) {
1368                         DBG("wildcard %s busy for this channel",
1369                                 event_param->name);
1370                         return ERR_PTR(-EEXIST);        /* Already there */
1371                 }
1372         }
1373         sw = zmalloc(sizeof(struct session_wildcard));
1374         if (!sw)
1375                 return ERR_PTR(-ENOMEM);
1376         sw->chan = chan;
1377         sw->enabled = 1;
1378         memcpy(&sw->event_param, event_param, sizeof(sw->event_param));
1379         sw->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
1380         sw->event_param.loglevel_type = event_param->loglevel_type;
1381         sw->event_param.loglevel = event_param->loglevel;
1382         CDS_INIT_LIST_HEAD(&sw->events);
1383         cds_list_add(&sw->list, &chan->session->wildcards);
1384         cds_list_add(&sw->session_list, &e->session_list);
1385         sw->entry = e;
1386         ltt_probes_create_wildcard_events(e, sw);
1387         return sw;
1388 }
1389
1390 /*
1391  * Remove the wildcard from the wildcard list. Must be called with
1392  * ust_lock held. Only called at session teardown.
1393  */
1394 static
1395 void _remove_wildcard(struct session_wildcard *wildcard)
1396 {
1397         struct ltt_event *ev, *tmp;
1398
1399         /*
1400          * Just remove the events owned (for enable/disable) by this
1401          * wildcard from the list. The session teardown will take care
1402          * of freeing the event memory.
1403          */
1404         cds_list_for_each_entry_safe(ev, tmp, &wildcard->events,
1405                         wildcard_list) {
1406                 cds_list_del(&ev->wildcard_list);
1407         }
1408         cds_list_del(&wildcard->session_list);
1409         cds_list_del(&wildcard->list);
1410         if (cds_list_empty(&wildcard->entry->session_list)) {
1411                 cds_list_del(&wildcard->entry->list);
1412                 free(wildcard->entry);
1413         }
1414         free(wildcard);
1415 }
1416
1417 int ltt_wildcard_create(struct ltt_channel *chan,
1418         struct lttng_ust_event *event_param,
1419         struct session_wildcard **_sw)
1420 {
1421         struct session_wildcard *sw;
1422
1423         sw = add_wildcard(chan, event_param);
1424         if (!sw || IS_ERR(sw)) {
1425                 return PTR_ERR(sw);
1426         }
1427         *_sw = sw;
1428         return 0;
1429 }
1430
1431 static
1432 void _ltt_wildcard_destroy(struct session_wildcard *sw)
1433 {
1434         _remove_wildcard(sw);
1435 }
1436
1437 int ltt_wildcard_enable(struct session_wildcard *wildcard)
1438 {
1439         struct ltt_event *ev;
1440         int ret;
1441
1442         if (wildcard->enabled)
1443                 return -EEXIST;
1444         cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
1445                 ret = ltt_event_enable(ev);
1446                 if (ret) {
1447                         DBG("Error: enable error.\n");
1448                         return ret;
1449                 }
1450         }
1451         wildcard->enabled = 1;
1452         return 0;
1453 }
1454
1455 int ltt_wildcard_disable(struct session_wildcard *wildcard)
1456 {
1457         struct ltt_event *ev;
1458         int ret;
1459
1460         if (!wildcard->enabled)
1461                 return -EEXIST;
1462         cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
1463                 ret = ltt_event_disable(ev);
1464                 if (ret) {
1465                         DBG("Error: disable error.\n");
1466                         return ret;
1467                 }
1468         }
1469         wildcard->enabled = 0;
1470         return 0;
1471 }
1472
1473 /*
1474  * Take the TLS "fault" in libuuid if dlopen'd, which can take the
1475  * dynamic linker mutex, outside of the UST lock, since the UST lock is
1476  * taken in constructors, which are called with dynamic linker mutex
1477  * held.
1478  */
1479 void lttng_fixup_event_tls(void)
1480 {
1481         unsigned char uuid[37];
1482
1483         (void) uuid_generate(uuid);
1484 }