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 <urcu/list.h>
  26 #include <urcu/hlist.h>
  27 #include <pthread.h>
  28 #include <errno.h>
  29 #include <sys/shm.h>
  30 #include <sys/ipc.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <inttypes.h>
  34 #include <time.h>
  35 #include <lttng/ust-endian.h>
  36 #include "clock.h"
  37
  38 #include <urcu-bp.h>
  39 #include <urcu/compiler.h>
  40 #include <urcu/uatomic.h>
  41 #include <urcu/arch.h>
  42
  43 #include <lttng/tracepoint.h>
  44 #include <lttng/ust-events.h>
  45
  46 #include <usterr-signal-safe.h>
  47 #include <helper.h>
  48 #include "error.h"
  49 #include "compat.h"
  50 #include "lttng-ust-uuid.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 /*
  60  * The sessions mutex is the centralized mutex across UST tracing
  61  * control and probe registration. All operations within this file are
  62  * called by the communication thread, under ust_lock protection.
  63  */
  64 static pthread_mutex_t sessions_mutex = PTHREAD_MUTEX_INITIALIZER;
  65
  66 void ust_lock(void)
  67 {
  68         pthread_mutex_lock(&sessions_mutex);
  69 }
  70
  71 void ust_unlock(void)
  72 {
  73         pthread_mutex_unlock(&sessions_mutex);
  74 }
  75
  76 static CDS_LIST_HEAD(sessions);
  77
  78 /*
  79  * Wildcard list, containing the active wildcards.
  80  * Protected by ust lock.
  81  */
  82 static CDS_LIST_HEAD(wildcard_list);
  83
  84 /*
  85  * Pending probes hash table, containing the registered ltt events for
  86  * which tracepoint probes are still missing. Protected by the sessions
  87  * mutex.
  88  */
  89 #define PENDING_PROBE_HASH_BITS         6
  90 #define PENDING_PROBE_HASH_SIZE         (1 << PENDING_PROBE_HASH_BITS)
  91 static struct cds_hlist_head pending_probe_table[PENDING_PROBE_HASH_SIZE];
  92
  93 struct ust_pending_probe {
  94         struct ltt_event *event;
  95         struct cds_hlist_node node;
  96         enum lttng_ust_loglevel_type loglevel_type;
  97         int loglevel;
  98         char name[];
  99 };
 100
 101 static void _ltt_event_destroy(struct ltt_event *event);
 102 static void _ltt_wildcard_destroy(struct session_wildcard *sw);
 103 static void _ltt_channel_destroy(struct ltt_channel *chan);
 104 static int _ltt_event_unregister(struct ltt_event *event);
 105 static
 106 int _ltt_event_metadata_statedump(struct ltt_session *session,
 107                                   struct ltt_channel *chan,
 108                                   struct ltt_event *event);
 109 static
 110 int _ltt_session_metadata_statedump(struct ltt_session *session);
 111
 112 int ltt_loglevel_match(const struct lttng_event_desc *desc,
 113                 enum lttng_ust_loglevel_type req_type,
 114                 int req_loglevel)
 115 {
 116         int ev_loglevel;
 117
 118         if (req_type == LTTNG_UST_LOGLEVEL_ALL)
 119                 return 1;
 120         if (!desc->loglevel)
 121                 ev_loglevel = TRACE_DEFAULT;
 122         else
 123                 ev_loglevel = *(*desc->loglevel);
 124         switch (req_type) {
 125         case LTTNG_UST_LOGLEVEL_RANGE:
 126                 if (ev_loglevel <= req_loglevel || req_loglevel == -1)
 127                         return 1;
 128                 else
 129                         return 0;
 130         case LTTNG_UST_LOGLEVEL_SINGLE:
 131                 if (ev_loglevel == req_loglevel || req_loglevel == -1)
 132                         return 1;
 133                 else
 134                         return 0;
 135         case LTTNG_UST_LOGLEVEL_ALL:
 136         default:
 137                 return 1;
 138         }
 139 }
 140
 141 /*
 142  * Return wildcard for a given event name if the event name match the
 143  * one of the wildcards.
 144  * Must be called with ust lock held.
 145  * Returns NULL if not present.
 146  */
 147 static
 148 struct wildcard_entry *match_wildcard(const struct lttng_event_desc *desc)
 149 {
 150         struct wildcard_entry *e;
 151
 152         cds_list_for_each_entry(e, &wildcard_list, list) {
 153                 /* If only contain '*' */
 154                 if (strlen(e->name) == 1)
 155                         goto possible_match;
 156                 /* Compare excluding final '*' */
 157                 if (!strncmp(desc->name, e->name, strlen(e->name) - 1))
 158                         goto possible_match;
 159                 continue;       /* goto next, no match */
 160         possible_match:
 161                 if (ltt_loglevel_match(desc,
 162                                 e->loglevel_type,
 163                                 e->loglevel)) {
 164                         return e;
 165                 }
 166                 /* no match, loop to next */
 167         }
 168         return NULL;
 169 }
 170
 171 /*
 172  * called at event creation if probe is missing.
 173  * called with session mutex held.
 174  */
 175 static
 176 int add_pending_probe(struct ltt_event *event, const char *name,
 177                 enum lttng_ust_loglevel_type loglevel_type,
 178                 int loglevel)
 179 {
 180         struct cds_hlist_head *head;
 181         struct ust_pending_probe *e;
 182         size_t name_len = strlen(name) + 1;
 183         uint32_t hash;
 184
 185         if (name_len > LTTNG_UST_SYM_NAME_LEN) {
 186                 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN);
 187                 name_len = LTTNG_UST_SYM_NAME_LEN;
 188         }
 189         hash = jhash(name, name_len - 1, 0);
 190         head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
 191         e = zmalloc(sizeof(struct ust_pending_probe) + name_len);
 192         if (!e)
 193                 return -ENOMEM;
 194         memcpy(&e->name[0], name, name_len);
 195         e->name[name_len - 1] = '\0';
 196         e->loglevel_type = loglevel_type;
 197         e->loglevel = loglevel;
 198         cds_hlist_add_head(&e->node, head);
 199         e->event = event;
 200         event->pending_probe = e;
 201         return 0;
 202 }
 203
 204 /*
 205  * remove a pending probe. called when at event teardown and when an
 206  * event is fixed (probe is loaded).
 207  * called with session mutex held.
 208  */
 209 static
 210 void remove_pending_probe(struct ust_pending_probe *e)
 211 {
 212         if (!e)
 213                 return;
 214         cds_hlist_del(&e->node);
 215         free(e);
 216 }
 217
 218 /*
 219  * Called at library load: connect the probe on the events pending on
 220  * probe load.
 221  * called with session mutex held.
 222  */
 223 int pending_probe_fix_events(const struct lttng_event_desc *desc)
 224 {
 225         struct cds_hlist_head *head;
 226         struct cds_hlist_node *node, *p;
 227         struct ust_pending_probe *e;
 228         const char *name = desc->name;
 229         int ret = 0;
 230         struct lttng_ust_event event_param;
 231         size_t name_len = strlen(name) + 1;
 232         uint32_t hash;
 233
 234         /* Wildcard */
 235         {
 236                 struct wildcard_entry *wildcard;
 237
 238                 wildcard = match_wildcard(desc);
 239                 if (strcmp(desc->name, "lttng_ust:metadata") && wildcard) {
 240                         struct session_wildcard *sw;
 241
 242                         cds_list_for_each_entry(sw, &wildcard->session_list,
 243                                         session_list) {
 244                                 struct ltt_event *ev;
 245                                 int ret;
 246
 247                                 memcpy(&event_param, &sw->event_param,
 248                                                 sizeof(event_param));
 249                                 strncpy(event_param.name,
 250                                         desc->name,
 251                                         sizeof(event_param.name));
 252                                 event_param.name[sizeof(event_param.name) - 1] = '\0';
 253                                 /* create event */
 254                                 ret = ltt_event_create(sw->chan,
 255                                         &event_param, NULL,
 256                                         &ev);
 257                                 if (ret) {
 258                                         DBG("Error creating event");
 259                                         continue;
 260                                 }
 261                                 cds_list_add(&ev->wildcard_list,
 262                                         &sw->events);
 263                         }
 264                 }
 265         }
 266
 267         if (name_len > LTTNG_UST_SYM_NAME_LEN) {
 268                 WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN);
 269                 name_len = LTTNG_UST_SYM_NAME_LEN;
 270         }
 271         hash = jhash(name, name_len - 1, 0);
 272         head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
 273         cds_hlist_for_each_entry_safe(e, node, p, head, node) {
 274                 struct ltt_event *event;
 275                 struct ltt_channel *chan;
 276
 277                 if (!ltt_loglevel_match(desc,
 278                                 e->loglevel_type,
 279                                 e->loglevel)) {
 280                         continue;
 281                 }
 282                 if (strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) {
 283                         continue;
 284                 }
 285                 event = e->event;
 286                 chan = event->chan;
 287                 assert(!event->desc);
 288                 event->desc = desc;
 289                 event->pending_probe = NULL;
 290                 remove_pending_probe(e);
 291                 ret |= __tracepoint_probe_register(name,
 292                                 event->desc->probe_callback,
 293                                 event, event->desc->signature);
 294                 if (ret)
 295                         continue;
 296                 event->id = chan->free_event_id++;
 297                 ret |= _ltt_event_metadata_statedump(chan->session, chan,
 298                                 event);
 299         }
 300         return ret;
 301 }
 302
 303 void synchronize_trace(void)
 304 {
 305         synchronize_rcu();
 306 }
 307
 308 struct ltt_session *ltt_session_create(void)
 309 {
 310         struct ltt_session *session;
 311         int ret;
 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         ret = lttng_ust_uuid_generate(session->uuid);
 320         if (ret != 0) {
 321                 session->uuid[0] = '\0';
 322         }
 323         cds_list_add(&session->list, &sessions);
 324         return session;
 325 }
 326
 327 void ltt_session_destroy(struct ltt_session *session)
 328 {
 329         struct ltt_channel *chan, *tmpchan;
 330         struct ltt_event *event, *tmpevent;
 331         struct session_wildcard *wildcard, *tmpwildcard;
 332         int ret;
 333
 334         CMM_ACCESS_ONCE(session->active) = 0;
 335         cds_list_for_each_entry(event, &session->events, list) {
 336                 ret = _ltt_event_unregister(event);
 337                 WARN_ON(ret);
 338         }
 339         synchronize_trace();    /* Wait for in-flight events to complete */
 340         cds_list_for_each_entry_safe(wildcard, tmpwildcard, &session->wildcards, list)
 341                 _ltt_wildcard_destroy(wildcard);
 342         cds_list_for_each_entry_safe(event, tmpevent, &session->events, list)
 343                 _ltt_event_destroy(event);
 344         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
 345                 _ltt_channel_destroy(chan);
 346         cds_list_del(&session->list);
 347         free(session);
 348 }
 349
 350 int ltt_session_enable(struct ltt_session *session)
 351 {
 352         int ret = 0;
 353         struct ltt_channel *chan;
 354
 355         if (session->active) {
 356                 ret = -EBUSY;
 357                 goto end;
 358         }
 359
 360         /*
 361          * Snapshot the number of events per channel to know the type of header
 362          * we need to use.
 363          */
 364         cds_list_for_each_entry(chan, &session->chan, list) {
 365                 if (chan->header_type)
 366                         continue;               /* don't change it if session stop/restart */
 367                 if (chan->free_event_id < 31)
 368                         chan->header_type = 1;  /* compact */
 369                 else
 370                         chan->header_type = 2;  /* large */
 371         }
 372
 373         CMM_ACCESS_ONCE(session->active) = 1;
 374         CMM_ACCESS_ONCE(session->been_active) = 1;
 375         ret = _ltt_session_metadata_statedump(session);
 376         if (ret)
 377                 CMM_ACCESS_ONCE(session->active) = 0;
 378 end:
 379         return ret;
 380 }
 381
 382 int ltt_session_disable(struct ltt_session *session)
 383 {
 384         int ret = 0;
 385
 386         if (!session->active) {
 387                 ret = -EBUSY;
 388                 goto end;
 389         }
 390         CMM_ACCESS_ONCE(session->active) = 0;
 391 end:
 392         return ret;
 393 }
 394
 395 int ltt_channel_enable(struct ltt_channel *channel)
 396 {
 397         int old;
 398
 399         if (channel == channel->session->metadata)
 400                 return -EPERM;
 401         old = uatomic_xchg(&channel->enabled, 1);
 402         if (old)
 403                 return -EEXIST;
 404         return 0;
 405 }
 406
 407 int ltt_channel_disable(struct ltt_channel *channel)
 408 {
 409         int old;
 410
 411         if (channel == channel->session->metadata)
 412                 return -EPERM;
 413         old = uatomic_xchg(&channel->enabled, 0);
 414         if (!old)
 415                 return -EEXIST;
 416         return 0;
 417 }
 418
 419 int ltt_event_enable(struct ltt_event *event)
 420 {
 421         int old;
 422
 423         if (event->chan == event->chan->session->metadata)
 424                 return -EPERM;
 425         old = uatomic_xchg(&event->enabled, 1);
 426         if (old)
 427                 return -EEXIST;
 428         return 0;
 429 }
 430
 431 int ltt_event_disable(struct ltt_event *event)
 432 {
 433         int old;
 434
 435         if (event->chan == event->chan->session->metadata)
 436                 return -EPERM;
 437         old = uatomic_xchg(&event->enabled, 0);
 438         if (!old)
 439                 return -EEXIST;
 440         return 0;
 441 }
 442
 443 struct ltt_channel *ltt_channel_create(struct ltt_session *session,
 444                                        const char *transport_name,
 445                                        void *buf_addr,
 446                                        size_t subbuf_size, size_t num_subbuf,
 447                                        unsigned int switch_timer_interval,
 448                                        unsigned int read_timer_interval,
 449                                        int **shm_fd, char **shm_path,
 450                                        int **wait_fd, char **wait_pipe_path,
 451                                        uint64_t **memory_map_size,
 452                                        struct ltt_channel *chan_priv_init)
 453 {
 454         struct ltt_channel *chan = NULL;
 455         struct ltt_transport *transport;
 456
 457         if (session->been_active)
 458                 goto active;    /* Refuse to add channel to active session */
 459         transport = ltt_transport_find(transport_name);
 460         if (!transport) {
 461                 DBG("LTTng transport %s not found\n",
 462                        transport_name);
 463                 goto notransport;
 464         }
 465         chan_priv_init->id = session->free_chan_id++;
 466         chan_priv_init->session = session;
 467         /*
 468          * Note: the channel creation op already writes into the packet
 469          * headers. Therefore the "chan" information used as input
 470          * should be already accessible.
 471          */
 472         chan = transport->ops.channel_create(transport_name, buf_addr,
 473                         subbuf_size, num_subbuf, switch_timer_interval,
 474                         read_timer_interval, shm_fd, shm_path,
 475                         wait_fd, wait_pipe_path, memory_map_size,
 476                         chan_priv_init);
 477         if (!chan)
 478                 goto create_error;
 479         chan->enabled = 1;
 480         chan->ops = &transport->ops;
 481         cds_list_add(&chan->list, &session->chan);
 482         return chan;
 483
 484 create_error:
 485 notransport:
 486 active:
 487         return NULL;
 488 }
 489
 490 /*
 491  * Only used internally at session destruction.
 492  */
 493 static
 494 void _ltt_channel_destroy(struct ltt_channel *chan)
 495 {
 496         cds_list_del(&chan->list);
 497         lttng_destroy_context(chan->ctx);
 498         chan->ops->channel_destroy(chan);
 499 }
 500
 501 /*
 502  * Supports event creation while tracing session is active.
 503  */
 504 int ltt_event_create(struct ltt_channel *chan,
 505                 struct lttng_ust_event *event_param,
 506                 void (*filter)(struct ltt_event *event),
 507                 struct ltt_event **_event)
 508 {
 509         const struct lttng_event_desc *desc = NULL;     /* silence gcc */
 510         struct ltt_event *event;
 511         int ret = 0;
 512
 513         if (chan->used_event_id == -1U) {
 514                 ret = -ENOMEM;
 515                 goto full;
 516         }
 517         /*
 518          * This is O(n^2) (for each event, the loop is called at event
 519          * creation). Might require a hash if we have lots of events.
 520          */
 521         cds_list_for_each_entry(event, &chan->session->events, list) {
 522                 if (event->desc && !strncmp(event->desc->name,
 523                                 event_param->name,
 524                                 LTTNG_UST_SYM_NAME_LEN - 1)) {
 525                         ret = -EEXIST;
 526                         goto exist;
 527                 }
 528         }
 529
 530         /*
 531          * Check if loglevel match. Refuse to connect event if not.
 532          */
 533         if (event_param->instrumentation == LTTNG_UST_TRACEPOINT) {
 534                 desc = ltt_event_get(event_param->name);
 535                 if (desc) {
 536                         if (!ltt_loglevel_match(desc,
 537                                         event_param->loglevel_type,
 538                                         event_param->loglevel)) {
 539                                 ret = -EPERM;
 540                                 goto no_loglevel_match;
 541                         }
 542                 }
 543                 /*
 544                  * If descriptor is not there, it will be added to
 545                  * pending probes.
 546                  */
 547         }
 548         event = zmalloc(sizeof(struct ltt_event));
 549         if (!event) {
 550                 ret = -ENOMEM;
 551                 goto cache_error;
 552         }
 553         event->chan = chan;
 554         event->filter = filter;
 555         /*
 556          * used_event_id counts the maximum number of event IDs that can
 557          * register if all probes register.
 558          */
 559         chan->used_event_id++;
 560         event->enabled = 1;
 561         event->instrumentation = event_param->instrumentation;
 562         /* Populate ltt_event structure before tracepoint registration. */
 563         cmm_smp_wmb();
 564         switch (event_param->instrumentation) {
 565         case LTTNG_UST_TRACEPOINT:
 566                 event->desc = desc;
 567                 if (event->desc) {
 568                         ret = __tracepoint_probe_register(event_param->name,
 569                                         event->desc->probe_callback,
 570                                         event, event->desc->signature);
 571                         if (ret)
 572                                 goto register_error;
 573                         event->id = chan->free_event_id++;
 574                 } else {
 575                         /*
 576                          * If the probe is not present, event->desc stays NULL,
 577                          * waiting for the probe to register, and the event->id
 578                          * stays unallocated.
 579                          */
 580                         ret = add_pending_probe(event, event_param->name,
 581                                         event_param->loglevel_type,
 582                                         event_param->loglevel);
 583                         if (ret)
 584                                 goto add_pending_error;
 585                 }
 586                 break;
 587         default:
 588                 WARN_ON_ONCE(1);
 589         }
 590         if (event->desc) {
 591                 ret = _ltt_event_metadata_statedump(chan->session, chan, event);
 592                 if (ret)
 593                         goto statedump_error;
 594         }
 595         cds_list_add(&event->list, &chan->session->events);
 596         *_event = event;
 597         return 0;
 598
 599 statedump_error:
 600         if (event->desc) {
 601                 WARN_ON_ONCE(__tracepoint_probe_unregister(event_param->name,
 602                                         event->desc->probe_callback,
 603                                         event));
 604                 ltt_event_put(event->desc);
 605         }
 606 add_pending_error:
 607 register_error:
 608         free(event);
 609 cache_error:
 610 no_loglevel_match:
 611 exist:
 612 full:
 613         return ret;
 614 }
 615
 616 /*
 617  * Only used internally at session destruction.
 618  */
 619 int _ltt_event_unregister(struct ltt_event *event)
 620 {
 621         int ret = -EINVAL;
 622
 623         switch (event->instrumentation) {
 624         case LTTNG_UST_TRACEPOINT:
 625                 if (event->desc) {
 626                         ret = __tracepoint_probe_unregister(event->desc->name,
 627                                                           event->desc->probe_callback,
 628                                                           event);
 629                         if (ret)
 630                                 return ret;
 631                 } else {
 632                         remove_pending_probe(event->pending_probe);
 633                         ret = 0;
 634                 }
 635                 break;
 636         default:
 637                 WARN_ON_ONCE(1);
 638         }
 639         return ret;
 640 }
 641
 642 /*
 643  * Only used internally at session destruction.
 644  */
 645 static
 646 void _ltt_event_destroy(struct ltt_event *event)
 647 {
 648         switch (event->instrumentation) {
 649         case LTTNG_UST_TRACEPOINT:
 650                 if (event->desc) {
 651                         ltt_event_put(event->desc);
 652                 }
 653                 break;
 654         default:
 655                 WARN_ON_ONCE(1);
 656         }
 657         cds_list_del(&event->list);
 658         lttng_destroy_context(event->ctx);
 659         free(event);
 660 }
 661
 662 /*
 663  * We have exclusive access to our metadata buffer (protected by the
 664  * ust_lock), so we can do racy operations such as looking for
 665  * remaining space left in packet and write, since mutual exclusion
 666  * protects us from concurrent writes.
 667  */
 668 int lttng_metadata_printf(struct ltt_session *session,
 669                           const char *fmt, ...)
 670 {
 671         struct lttng_ust_lib_ring_buffer_ctx ctx;
 672         struct ltt_channel *chan = session->metadata;
 673         char *str = NULL;
 674         int ret = 0, waitret;
 675         size_t len, reserve_len, pos;
 676         va_list ap;
 677
 678         WARN_ON_ONCE(!CMM_ACCESS_ONCE(session->active));
 679
 680         va_start(ap, fmt);
 681         ret = vasprintf(&str, fmt, ap);
 682         va_end(ap);
 683         if (ret < 0)
 684                 return -ENOMEM;
 685
 686         len = strlen(str);
 687         pos = 0;
 688
 689         for (pos = 0; pos < len; pos += reserve_len) {
 690                 reserve_len = min_t(size_t,
 691                                 chan->ops->packet_avail_size(chan->chan, chan->handle),
 692                                 len - pos);
 693                 lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len,
 694                                          sizeof(char), -1, chan->handle);
 695                 /*
 696                  * We don't care about metadata buffer's records lost
 697                  * count, because we always retry here. Report error if
 698                  * we need to bail out after timeout or being
 699                  * interrupted.
 700                  */
 701                 waitret = wait_cond_interruptible_timeout(
 702                         ({
 703                                 ret = chan->ops->event_reserve(&ctx, 0);
 704                                 ret != -ENOBUFS || !ret;
 705                         }),
 706                         LTTNG_METADATA_TIMEOUT_MSEC);
 707                 if (waitret == -ETIMEDOUT || waitret == -EINTR || ret) {
 708                         DBG("LTTng: Failure to write metadata to buffers (%s)\n",
 709                                 waitret == -EINTR ? "interrupted" :
 710                                         (ret == -ENOBUFS ? "timeout" : "I/O error"));
 711                         if (waitret == -EINTR)
 712                                 ret = waitret;
 713                         goto end;
 714                 }
 715                 chan->ops->event_write(&ctx, &str[pos], reserve_len);
 716                 chan->ops->event_commit(&ctx);
 717         }
 718 end:
 719         free(str);
 720         return ret;
 721 }
 722
 723 static
 724 int _ltt_field_statedump(struct ltt_session *session,
 725                          const struct lttng_event_field *field)
 726 {
 727         int ret = 0;
 728
 729         switch (field->type.atype) {
 730         case atype_integer:
 731                 ret = lttng_metadata_printf(session,
 732                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
 733                         field->type.u.basic.integer.size,
 734                         field->type.u.basic.integer.alignment,
 735                         field->type.u.basic.integer.signedness,
 736                         (field->type.u.basic.integer.encoding == lttng_encode_none)
 737                                 ? "none"
 738                                 : (field->type.u.basic.integer.encoding == lttng_encode_UTF8)
 739                                         ? "UTF8"
 740                                         : "ASCII",
 741                         field->type.u.basic.integer.base,
 742 #if (BYTE_ORDER == BIG_ENDIAN)
 743                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 744 #else
 745                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 746 #endif
 747                         field->name);
 748                 break;
 749         case atype_float:
 750                 ret = lttng_metadata_printf(session,
 751                         "               floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
 752                         field->type.u.basic._float.exp_dig,
 753                         field->type.u.basic._float.mant_dig,
 754                         field->type.u.basic._float.alignment,
 755 #if (BYTE_ORDER == BIG_ENDIAN)
 756                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 757 #else
 758                         field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 759 #endif
 760                         field->name);
 761                 break;
 762         case atype_enum:
 763                 ret = lttng_metadata_printf(session,
 764                         "               %s %s;\n",
 765                         field->type.u.basic.enumeration.name,
 766                         field->name);
 767                 break;
 768         case atype_array:
 769         {
 770                 const struct lttng_basic_type *elem_type;
 771
 772                 elem_type = &field->type.u.array.elem_type;
 773                 ret = lttng_metadata_printf(session,
 774                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
 775                         elem_type->u.basic.integer.size,
 776                         elem_type->u.basic.integer.alignment,
 777                         elem_type->u.basic.integer.signedness,
 778                         (elem_type->u.basic.integer.encoding == lttng_encode_none)
 779                                 ? "none"
 780                                 : (elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
 781                                         ? "UTF8"
 782                                         : "ASCII",
 783                         elem_type->u.basic.integer.base,
 784 #if (BYTE_ORDER == BIG_ENDIAN)
 785                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 786 #else
 787                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 788 #endif
 789                         field->name, field->type.u.array.length);
 790                 break;
 791         }
 792         case atype_sequence:
 793         {
 794                 const struct lttng_basic_type *elem_type;
 795                 const struct lttng_basic_type *length_type;
 796
 797                 elem_type = &field->type.u.sequence.elem_type;
 798                 length_type = &field->type.u.sequence.length_type;
 799                 ret = lttng_metadata_printf(session,
 800                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
 801                         length_type->u.basic.integer.size,
 802                         (unsigned int) length_type->u.basic.integer.alignment,
 803                         length_type->u.basic.integer.signedness,
 804                         (length_type->u.basic.integer.encoding == lttng_encode_none)
 805                                 ? "none"
 806                                 : ((length_type->u.basic.integer.encoding == lttng_encode_UTF8)
 807                                         ? "UTF8"
 808                                         : "ASCII"),
 809                         length_type->u.basic.integer.base,
 810 #if (BYTE_ORDER == BIG_ENDIAN)
 811                         length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 812 #else
 813                         length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 814 #endif
 815                         field->name);
 816                 if (ret)
 817                         return ret;
 818
 819                 ret = lttng_metadata_printf(session,
 820                         "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
 821                         elem_type->u.basic.integer.size,
 822                         (unsigned int) elem_type->u.basic.integer.alignment,
 823                         elem_type->u.basic.integer.signedness,
 824                         (elem_type->u.basic.integer.encoding == lttng_encode_none)
 825                                 ? "none"
 826                                 : ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
 827                                         ? "UTF8"
 828                                         : "ASCII"),
 829                         elem_type->u.basic.integer.base,
 830 #if (BYTE_ORDER == BIG_ENDIAN)
 831                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
 832 #else
 833                         elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
 834 #endif
 835                         field->name,
 836                         field->name);
 837                 break;
 838         }
 839
 840         case atype_string:
 841                 /* Default encoding is UTF8 */
 842                 ret = lttng_metadata_printf(session,
 843                         "               string%s _%s;\n",
 844                         field->type.u.basic.string.encoding == lttng_encode_ASCII ?
 845                                 " { encoding = ASCII; }" : "",
 846                         field->name);
 847                 break;
 848         default:
 849                 WARN_ON_ONCE(1);
 850                 return -EINVAL;
 851         }
 852         return ret;
 853 }
 854
 855 static
 856 int _ltt_context_metadata_statedump(struct ltt_session *session,
 857                                     struct lttng_ctx *ctx)
 858 {
 859         int ret = 0;
 860         int i;
 861
 862         if (!ctx)
 863                 return 0;
 864         for (i = 0; i < ctx->nr_fields; i++) {
 865                 const struct lttng_ctx_field *field = &ctx->fields[i];
 866
 867                 ret = _ltt_field_statedump(session, &field->event_field);
 868                 if (ret)
 869                         return ret;
 870         }
 871         return ret;
 872 }
 873
 874 static
 875 int _ltt_fields_metadata_statedump(struct ltt_session *session,
 876                                    struct ltt_event *event)
 877 {
 878         const struct lttng_event_desc *desc = event->desc;
 879         int ret = 0;
 880         int i;
 881
 882         for (i = 0; i < desc->nr_fields; i++) {
 883                 const struct lttng_event_field *field = &desc->fields[i];
 884
 885                 ret = _ltt_field_statedump(session, field);
 886                 if (ret)
 887                         return ret;
 888         }
 889         return ret;
 890 }
 891
 892 static
 893 int _ltt_event_metadata_statedump(struct ltt_session *session,
 894                                   struct ltt_channel *chan,
 895                                   struct ltt_event *event)
 896 {
 897         int ret = 0;
 898         int loglevel = TRACE_DEFAULT;
 899
 900         if (event->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
 901                 return 0;
 902         if (chan == session->metadata)
 903                 return 0;
 904         /*
 905          * Don't print events for which probe load is pending.
 906          */
 907         if (!event->desc)
 908                 return 0;
 909
 910         ret = lttng_metadata_printf(session,
 911                 "event {\n"
 912                 "       name = \"%s\";\n"
 913                 "       id = %u;\n"
 914                 "       stream_id = %u;\n",
 915                 event->desc->name,
 916                 event->id,
 917                 event->chan->id);
 918         if (ret)
 919                 goto end;
 920
 921         if (event->desc->loglevel)
 922                 loglevel = *(*event->desc->loglevel);
 923
 924         ret = lttng_metadata_printf(session,
 925                 "       loglevel = %d;\n",
 926                 loglevel);
 927         if (ret)
 928                 goto end;
 929
 930         if (event->ctx) {
 931                 ret = lttng_metadata_printf(session,
 932                         "       context := struct {\n");
 933                 if (ret)
 934                         goto end;
 935         }
 936         ret = _ltt_context_metadata_statedump(session, event->ctx);
 937         if (ret)
 938                 goto end;
 939         if (event->ctx) {
 940                 ret = lttng_metadata_printf(session,
 941                         "       };\n");
 942                 if (ret)
 943                         goto end;
 944         }
 945
 946         ret = lttng_metadata_printf(session,
 947                 "       fields := struct {\n"
 948                 );
 949         if (ret)
 950                 goto end;
 951
 952         ret = _ltt_fields_metadata_statedump(session, event);
 953         if (ret)
 954                 goto end;
 955
 956         /*
 957          * LTTng space reservation can only reserve multiples of the
 958          * byte size.
 959          */
 960         ret = lttng_metadata_printf(session,
 961                 "       };\n"
 962                 "};\n\n");
 963         if (ret)
 964                 goto end;
 965
 966         event->metadata_dumped = 1;
 967 end:
 968         return ret;
 969
 970 }
 971
 972 static
 973 int _ltt_channel_metadata_statedump(struct ltt_session *session,
 974                                     struct ltt_channel *chan)
 975 {
 976         int ret = 0;
 977
 978         if (chan->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
 979                 return 0;
 980         if (chan == session->metadata)
 981                 return 0;
 982
 983         WARN_ON_ONCE(!chan->header_type);
 984         ret = lttng_metadata_printf(session,
 985                 "stream {\n"
 986                 "       id = %u;\n"
 987                 "       event.header := %s;\n"
 988                 "       packet.context := struct packet_context;\n",
 989                 chan->id,
 990                 chan->header_type == 1 ? "struct event_header_compact" :
 991                         "struct event_header_large");
 992         if (ret)
 993                 goto end;
 994
 995         if (chan->ctx) {
 996                 ret = lttng_metadata_printf(session,
 997                         "       event.context := struct {\n");
 998                 if (ret)
 999                         goto end;
1000         }
1001         ret = _ltt_context_metadata_statedump(session, chan->ctx);
1002         if (ret)
1003                 goto end;
1004         if (chan->ctx) {
1005                 ret = lttng_metadata_printf(session,
1006                         "       };\n");
1007                 if (ret)
1008                         goto end;
1009         }
1010
1011         ret = lttng_metadata_printf(session,
1012                 "};\n\n");
1013
1014         chan->metadata_dumped = 1;
1015 end:
1016         return ret;
1017 }
1018
1019 static
1020 int _ltt_stream_packet_context_declare(struct ltt_session *session)
1021 {
1022         return lttng_metadata_printf(session,
1023                 "struct packet_context {\n"
1024                 "       uint64_clock_monotonic_t timestamp_begin;\n"
1025                 "       uint64_clock_monotonic_t timestamp_end;\n"
1026                 "       uint32_t events_discarded;\n"
1027                 "       uint32_t content_size;\n"
1028                 "       uint32_t packet_size;\n"
1029                 "       uint32_t cpu_id;\n"
1030                 "};\n\n"
1031                 );
1032 }
1033
1034 /*
1035  * Compact header:
1036  * id: range: 0 - 30.
1037  * id 31 is reserved to indicate an extended header.
1038  *
1039  * Large header:
1040  * id: range: 0 - 65534.
1041  * id 65535 is reserved to indicate an extended header.
1042  */
1043 static
1044 int _ltt_event_header_declare(struct ltt_session *session)
1045 {
1046         return lttng_metadata_printf(session,
1047         "struct event_header_compact {\n"
1048         "       enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
1049         "       variant <id> {\n"
1050         "               struct {\n"
1051         "                       uint27_clock_monotonic_t timestamp;\n"
1052         "               } compact;\n"
1053         "               struct {\n"
1054         "                       uint32_t id;\n"
1055         "                       uint64_clock_monotonic_t timestamp;\n"
1056         "               } extended;\n"
1057         "       } v;\n"
1058         "} align(%u);\n"
1059         "\n"
1060         "struct event_header_large {\n"
1061         "       enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
1062         "       variant <id> {\n"
1063         "               struct {\n"
1064         "                       uint32_clock_monotonic_t timestamp;\n"
1065         "               } compact;\n"
1066         "               struct {\n"
1067         "                       uint32_t id;\n"
1068         "                       uint64_clock_monotonic_t timestamp;\n"
1069         "               } extended;\n"
1070         "       } v;\n"
1071         "} align(%u);\n\n",
1072         lttng_alignof(uint32_t) * CHAR_BIT,
1073         lttng_alignof(uint16_t) * CHAR_BIT
1074         );
1075 }
1076
1077 /*
1078  * Approximation of NTP time of day to clock monotonic correlation,
1079  * taken at start of trace.
1080  * Yes, this is only an approximation. Yes, we can (and will) do better
1081  * in future versions.
1082  */
1083 static
1084 uint64_t measure_clock_offset(void)
1085 {
1086         uint64_t offset, monotonic[2], realtime;
1087         struct timespec rts = { 0, 0 };
1088         int ret;
1089
1090         monotonic[0] = trace_clock_read64();
1091         ret = clock_gettime(CLOCK_REALTIME, &rts);
1092         if (ret < 0)
1093                 return 0;
1094         monotonic[1] = trace_clock_read64();
1095         offset = (monotonic[0] + monotonic[1]) >> 1;
1096         realtime = (uint64_t) rts.tv_sec * 1000000000ULL;
1097         realtime += rts.tv_nsec;
1098         offset = realtime - offset;
1099         return offset;
1100 }
1101
1102 /*
1103  * Output metadata into this session's metadata buffers.
1104  */
1105 static
1106 int _ltt_session_metadata_statedump(struct ltt_session *session)
1107 {
1108         unsigned char *uuid_c = session->uuid;
1109         char uuid_s[LTTNG_UST_UUID_STR_LEN],
1110                 clock_uuid_s[LTTNG_UST_UUID_STR_LEN];
1111         struct ltt_channel *chan;
1112         struct ltt_event *event;
1113         int ret = 0;
1114         char procname[LTTNG_UST_PROCNAME_LEN] = "";
1115
1116         if (!CMM_ACCESS_ONCE(session->active))
1117                 return 0;
1118         if (session->metadata_dumped)
1119                 goto skip_session;
1120         if (!session->metadata) {
1121                 DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
1122                 return -EPERM;
1123         }
1124
1125         snprintf(uuid_s, sizeof(uuid_s),
1126                 "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
1127                 uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
1128                 uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
1129                 uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
1130                 uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
1131
1132         ret = lttng_metadata_printf(session,
1133                 "typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
1134                 "typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
1135                 "typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
1136                 "typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
1137                 "typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
1138                 "typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
1139                 "\n"
1140                 "trace {\n"
1141                 "       major = %u;\n"
1142                 "       minor = %u;\n"
1143                 "       uuid = \"%s\";\n"
1144                 "       byte_order = %s;\n"
1145                 "       packet.header := struct {\n"
1146                 "               uint32_t magic;\n"
1147                 "               uint8_t  uuid[16];\n"
1148                 "               uint32_t stream_id;\n"
1149                 "       };\n"
1150                 "};\n\n",
1151                 lttng_alignof(uint8_t) * CHAR_BIT,
1152                 lttng_alignof(uint16_t) * CHAR_BIT,
1153                 lttng_alignof(uint32_t) * CHAR_BIT,
1154                 lttng_alignof(uint64_t) * CHAR_BIT,
1155                 CTF_SPEC_MAJOR,
1156                 CTF_SPEC_MINOR,
1157                 uuid_s,
1158 #if (BYTE_ORDER == BIG_ENDIAN)
1159                 "be"
1160 #else
1161                 "le"
1162 #endif
1163                 );
1164         if (ret)
1165                 goto end;
1166
1167         /* ignore error, just use empty string if error. */
1168         lttng_ust_getprocname(procname);
1169         procname[LTTNG_UST_PROCNAME_LEN - 1] = '\0';
1170         ret = lttng_metadata_printf(session,
1171                 "env {\n"
1172                 "       vpid = %d;\n"
1173                 "       procname = \"%s\";\n"
1174                 "       domain = \"ust\";\n"
1175                 "       tracer_name = \"lttng-ust\";\n"
1176                 "       tracer_major = %u;\n"
1177                 "       tracer_minor = %u;\n"
1178                 "       tracer_patchlevel = %u;\n"
1179                 "};\n\n",
1180                 (int) getpid(),
1181                 procname,
1182                 LTTNG_UST_MAJOR_VERSION,
1183                 LTTNG_UST_MINOR_VERSION,
1184                 LTTNG_UST_PATCHLEVEL_VERSION
1185                 );
1186         if (ret)
1187                 goto end;
1188
1189         ret = lttng_metadata_printf(session,
1190                 "clock {\n"
1191                 "       name = %s;\n",
1192                 "monotonic"
1193                 );
1194         if (ret)
1195                 goto end;
1196
1197         if (!trace_clock_uuid(clock_uuid_s)) {
1198                 ret = lttng_metadata_printf(session,
1199                         "       uuid = \"%s\";\n",
1200                         clock_uuid_s
1201                         );
1202                 if (ret)
1203                         goto end;
1204         }
1205
1206         ret = lttng_metadata_printf(session,
1207                 "       description = \"Monotonic Clock\";\n"
1208                 "       freq = %" PRIu64 "; /* Frequency, in Hz */\n"
1209                 "       /* clock value offset from Epoch is: offset * (1/freq) */\n"
1210                 "       offset = %" PRIu64 ";\n"
1211                 "};\n\n",
1212                 trace_clock_freq(),
1213                 measure_clock_offset()
1214                 );
1215         if (ret)
1216                 goto end;
1217
1218         ret = lttng_metadata_printf(session,
1219                 "typealias integer {\n"
1220                 "       size = 27; align = 1; signed = false;\n"
1221                 "       map = clock.monotonic.value;\n"
1222                 "} := uint27_clock_monotonic_t;\n"
1223                 "\n"
1224                 "typealias integer {\n"
1225                 "       size = 32; align = %u; signed = false;\n"
1226                 "       map = clock.monotonic.value;\n"
1227                 "} := uint32_clock_monotonic_t;\n"
1228                 "\n"
1229                 "typealias integer {\n"
1230                 "       size = 64; align = %u; signed = false;\n"
1231                 "       map = clock.monotonic.value;\n"
1232                 "} := uint64_clock_monotonic_t;\n\n",
1233                 lttng_alignof(uint32_t) * CHAR_BIT,
1234                 lttng_alignof(uint64_t) * CHAR_BIT
1235                 );
1236         if (ret)
1237                 goto end;
1238
1239         ret = _ltt_stream_packet_context_declare(session);
1240         if (ret)
1241                 goto end;
1242
1243         ret = _ltt_event_header_declare(session);
1244         if (ret)
1245                 goto end;
1246
1247 skip_session:
1248         cds_list_for_each_entry(chan, &session->chan, list) {
1249                 ret = _ltt_channel_metadata_statedump(session, chan);
1250                 if (ret)
1251                         goto end;
1252         }
1253
1254         cds_list_for_each_entry(event, &session->events, list) {
1255                 ret = _ltt_event_metadata_statedump(session, event->chan, event);
1256                 if (ret)
1257                         goto end;
1258         }
1259         session->metadata_dumped = 1;
1260 end:
1261         return ret;
1262 }
1263
1264 void lttng_ust_events_exit(void)
1265 {
1266         struct ltt_session *session, *tmpsession;
1267
1268         cds_list_for_each_entry_safe(session, tmpsession, &sessions, list)
1269                 ltt_session_destroy(session);
1270 }
1271
1272 /* WILDCARDS */
1273
1274 static
1275 int wildcard_same_loglevel(struct wildcard_entry *e,
1276         enum lttng_ust_loglevel_type loglevel_type,
1277         int loglevel)
1278 {
1279         if (e->loglevel_type == loglevel_type && e->loglevel == loglevel)
1280                 return 1;
1281         else
1282                 return 0;
1283 }
1284
1285 #if 0
1286 static
1287 int wildcard_is_within(struct wildcard_entry *e,
1288         enum lttng_ust_loglevel_type loglevel_type,
1289         int loglevel)
1290 {
1291         if (e->loglevel_type == LTTNG_UST_LOGLEVEL_ALL
1292                         || e->loglevel == -1)
1293                 return 1;
1294         switch (e->loglevel_type) {
1295         case LTTNG_UST_LOGLEVEL_RANGE:
1296                 switch (loglevel_type) {
1297                 case LTTNG_UST_LOGLEVEL_RANGE:
1298                         if (e->loglevel >= loglevel)
1299                                 return 1;
1300                         else
1301                                 return 0;
1302                 case LTTNG_UST_LOGLEVEL_SINGLE:
1303                         if (e->loglevel <= 0 && loglevel == 0)
1304                                 return 1;
1305                         else
1306                                 return 0;
1307                 }
1308         case LTTNG_UST_LOGLEVEL_SINGLE:
1309                 switch (loglevel_type) {
1310                 case LTTNG_UST_LOGLEVEL_RANGE:
1311                         if (loglevel <= 0)
1312                                 return 1;
1313                         else
1314                                 return 0;
1315                 case LTTNG_UST_LOGLEVEL_SINGLE:
1316                         if (e->loglevel == loglevel)
1317                                 return 1;
1318                         else
1319                                 return 0;
1320                 }
1321         }
1322 }
1323 #endif
1324
1325 /*
1326  * Add the wildcard to the wildcard list. Must be called with
1327  * ust lock held.
1328  */
1329 static
1330 struct session_wildcard *add_wildcard(struct ltt_channel *chan,
1331         struct lttng_ust_event *event_param)
1332 {
1333         struct wildcard_entry *e;
1334         struct session_wildcard *sw;
1335         size_t name_len = strlen(event_param->name) + 1;
1336         int found = 0;
1337
1338         /*
1339          * Try to find global wildcard entry. Given that this is shared
1340          * across all sessions, we need to check for exact loglevel
1341          * match, not just whether contained within the existing ones.
1342          */
1343         cds_list_for_each_entry(e, &wildcard_list, list) {
1344                 if (!strncmp(event_param->name, e->name,
1345                                 LTTNG_UST_SYM_NAME_LEN - 1)) {
1346                         if (wildcard_same_loglevel(e,
1347                                         event_param->loglevel_type,
1348                                         event_param->loglevel)) {
1349                                 found = 1;
1350                                 break;
1351                         }
1352                 }
1353         }
1354
1355         if (!found) {
1356                 /*
1357                  * Create global wildcard entry if not found. Using
1358                  * zmalloc here to allocate a variable length element.
1359                  * Could cause some memory fragmentation if overused.
1360                  */
1361                 e = zmalloc(sizeof(struct wildcard_entry) + name_len);
1362                 if (!e)
1363                         return ERR_PTR(-ENOMEM);
1364                 memcpy(&e->name[0], event_param->name, name_len);
1365                 e->loglevel_type = event_param->loglevel_type;
1366                 e->loglevel = event_param->loglevel;
1367                 cds_list_add(&e->list, &wildcard_list);
1368                 CDS_INIT_LIST_HEAD(&e->session_list);
1369         }
1370
1371         /* session wildcard */
1372         cds_list_for_each_entry(sw, &e->session_list, session_list) {
1373                 if (chan == sw->chan) {
1374                         DBG("wildcard %s busy for this channel",
1375                                 event_param->name);
1376                         return ERR_PTR(-EEXIST);        /* Already there */
1377                 }
1378         }
1379         sw = zmalloc(sizeof(struct session_wildcard));
1380         if (!sw)
1381                 return ERR_PTR(-ENOMEM);
1382         sw->chan = chan;
1383         sw->enabled = 1;
1384         memcpy(&sw->event_param, event_param, sizeof(sw->event_param));
1385         sw->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
1386         sw->event_param.loglevel_type = event_param->loglevel_type;
1387         sw->event_param.loglevel = event_param->loglevel;
1388         CDS_INIT_LIST_HEAD(&sw->events);
1389         cds_list_add(&sw->list, &chan->session->wildcards);
1390         cds_list_add(&sw->session_list, &e->session_list);
1391         sw->entry = e;
1392         ltt_probes_create_wildcard_events(e, sw);
1393         return sw;
1394 }
1395
1396 /*
1397  * Remove the wildcard from the wildcard list. Must be called with
1398  * ust_lock held. Only called at session teardown.
1399  */
1400 static
1401 void _remove_wildcard(struct session_wildcard *wildcard)
1402 {
1403         struct ltt_event *ev, *tmp;
1404
1405         /*
1406          * Just remove the events owned (for enable/disable) by this
1407          * wildcard from the list. The session teardown will take care
1408          * of freeing the event memory.
1409          */
1410         cds_list_for_each_entry_safe(ev, tmp, &wildcard->events,
1411                         wildcard_list) {
1412                 cds_list_del(&ev->wildcard_list);
1413         }
1414         cds_list_del(&wildcard->session_list);
1415         cds_list_del(&wildcard->list);
1416         if (cds_list_empty(&wildcard->entry->session_list)) {
1417                 cds_list_del(&wildcard->entry->list);
1418                 free(wildcard->entry);
1419         }
1420         free(wildcard);
1421 }
1422
1423 int ltt_wildcard_create(struct ltt_channel *chan,
1424         struct lttng_ust_event *event_param,
1425         struct session_wildcard **_sw)
1426 {
1427         struct session_wildcard *sw;
1428
1429         sw = add_wildcard(chan, event_param);
1430         if (!sw || IS_ERR(sw)) {
1431                 return PTR_ERR(sw);
1432         }
1433         *_sw = sw;
1434         return 0;
1435 }
1436
1437 static
1438 void _ltt_wildcard_destroy(struct session_wildcard *sw)
1439 {
1440         _remove_wildcard(sw);
1441 }
1442
1443 int ltt_wildcard_enable(struct session_wildcard *wildcard)
1444 {
1445         struct ltt_event *ev;
1446         int ret;
1447
1448         if (wildcard->enabled)
1449                 return -EEXIST;
1450         cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
1451                 ret = ltt_event_enable(ev);
1452                 if (ret) {
1453                         DBG("Error: enable error.\n");
1454                         return ret;
1455                 }
1456         }
1457         wildcard->enabled = 1;
1458         return 0;
1459 }
1460
1461 int ltt_wildcard_disable(struct session_wildcard *wildcard)
1462 {
1463         struct ltt_event *ev;
1464         int ret;
1465
1466         if (!wildcard->enabled)
1467                 return -EEXIST;
1468         cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
1469                 ret = ltt_event_disable(ev);
1470                 if (ret) {
1471                         DBG("Error: disable error.\n");
1472                         return ret;
1473                 }
1474         }
1475         wildcard->enabled = 0;
1476         return 0;
1477 }
1478
1479 /*
1480  * Take the TLS "fault" in libuuid if dlopen'd, which can take the
1481  * dynamic linker mutex, outside of the UST lock, since the UST lock is
1482  * taken in constructors, which are called with dynamic linker mutex
1483  * held.
1484  */
1485 void lttng_fixup_event_tls(void)
1486 {
1487         unsigned char uuid[37];
1488
1489         (void) uuid_generate(uuid);
1490 }