liblttng-ust/ltt-probes.c

   1 /*
   2  * ltt-probes.c
   3  *
   4  * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Holds LTTng probes registry.
   7  *
   8  * Dual LGPL v2.1/GPL v2 license.
   9  */
  10
  11 #include <string.h>
  12 #include <errno.h>
  13 #include <urcu/list.h>
  14 #include <urcu/hlist.h>
  15 #include <lttng/ust-events.h>
  16 #include <assert.h>
  17 #include <helper.h>
  18 #include <ctype.h>
  19
  20 #include "ltt-tracer-core.h"
  21 #include "jhash.h"
  22 #include "error.h"
  23
  24 /*
  25  * probe list is protected by ust_lock()/ust_unlock().
  26  */
  27 static CDS_LIST_HEAD(probe_list);
  28
  29 /*
  30  * Loglevel hash table, containing the active loglevels.
  31  * Protected by ust lock.
  32  */
  33 #define LOGLEVEL_HASH_BITS 6
  34 #define LOGLEVEL_TABLE_SIZE (1 << LOGLEVEL_HASH_BITS)
  35 static struct cds_hlist_head loglevel_table[LOGLEVEL_TABLE_SIZE];
  36
  37 /*
  38  * Wildcard list, containing the active wildcards.
  39  * Protected by ust lock.
  40  */
  41 static CDS_LIST_HEAD(wildcard_list);
  42
  43 static
  44 const struct lttng_probe_desc *find_provider(const char *provider)
  45 {
  46         struct lttng_probe_desc *iter;
  47
  48         cds_list_for_each_entry(iter, &probe_list, head) {
  49                 if (!strcmp(iter->provider, provider))
  50                         return iter;
  51         }
  52         return NULL;
  53 }
  54
  55 static
  56 const struct lttng_event_desc *find_event(const char *name)
  57 {
  58         struct lttng_probe_desc *probe_desc;
  59         int i;
  60
  61         cds_list_for_each_entry(probe_desc, &probe_list, head) {
  62                 for (i = 0; i < probe_desc->nr_events; i++) {
  63                         if (!strncmp(probe_desc->event_desc[i]->name, name,
  64                                         LTTNG_UST_SYM_NAME_LEN - 1))
  65                                 return probe_desc->event_desc[i];
  66                 }
  67         }
  68         return NULL;
  69 }
  70
  71 int ltt_probe_register(struct lttng_probe_desc *desc)
  72 {
  73         struct lttng_probe_desc *iter;
  74         int ret = 0;
  75         int i;
  76
  77         ust_lock();
  78         if (find_provider(desc->provider)) {
  79                 ret = -EEXIST;
  80                 goto end;
  81         }
  82         /*
  83          * TODO: This is O(N^2). Turn into a hash table when probe registration
  84          * overhead becomes an issue.
  85          */
  86         for (i = 0; i < desc->nr_events; i++) {
  87                 if (find_event(desc->event_desc[i]->name)) {
  88                         ret = -EEXIST;
  89                         goto end;
  90                 }
  91         }
  92
  93         /*
  94          * We sort the providers by struct lttng_probe_desc pointer
  95          * address.
  96          */
  97         cds_list_for_each_entry_reverse(iter, &probe_list, head) {
  98                 BUG_ON(iter == desc); /* Should never be in the list twice */
  99                 if (iter < desc) {
 100                         /* We belong to the location right after iter. */
 101                         cds_list_add(&desc->head, &iter->head);
 102                         goto desc_added;
 103                 }
 104         }
 105         /* We should be added at the head of the list */
 106         cds_list_add(&desc->head, &probe_list);
 107 desc_added:
 108
 109         /*
 110          * fix the events awaiting probe load.
 111          */
 112         for (i = 0; i < desc->nr_events; i++) {
 113                 ret = pending_probe_fix_events(desc->event_desc[i]);
 114                 assert(!ret);
 115         }
 116 end:
 117         ust_unlock();
 118         return ret;
 119 }
 120
 121 void ltt_probe_unregister(struct lttng_probe_desc *desc)
 122 {
 123         ust_lock();
 124         cds_list_del(&desc->head);
 125         ust_unlock();
 126 }
 127
 128 /*
 129  * called with UST lock held.
 130  */
 131 const struct lttng_event_desc *ltt_event_get(const char *name)
 132 {
 133         const struct lttng_event_desc *event;
 134
 135         event = find_event(name);
 136         if (!event)
 137                 return NULL;
 138         return event;
 139 }
 140
 141 void ltt_event_put(const struct lttng_event_desc *event)
 142 {
 143 }
 144
 145 void ltt_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
 146 {
 147         struct tp_list_entry *list_entry, *tmp;
 148
 149         cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
 150                 cds_list_del(&list_entry->head);
 151                 free(list_entry);
 152         }
 153 }
 154
 155 /*
 156  * called with UST lock held.
 157  */
 158 int ltt_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
 159 {
 160         struct lttng_probe_desc *probe_desc;
 161         int i;
 162
 163         CDS_INIT_LIST_HEAD(&list->head);
 164         cds_list_for_each_entry(probe_desc, &probe_list, head) {
 165                 for (i = 0; i < probe_desc->nr_events; i++) {
 166                         struct tp_list_entry *list_entry;
 167
 168                         list_entry = zmalloc(sizeof(*list_entry));
 169                         if (!list_entry)
 170                                 goto err_nomem;
 171                         cds_list_add(&list_entry->head, &list->head);
 172                         strncpy(list_entry->tp.name,
 173                                 probe_desc->event_desc[i]->name,
 174                                 LTTNG_UST_SYM_NAME_LEN);
 175                         list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 176                         if (!probe_desc->event_desc[i]->loglevel) {
 177                                 list_entry->tp.loglevel[0] = '\0';
 178                                 list_entry->tp.loglevel_value = 0;
 179                         } else {
 180                                 strncpy(list_entry->tp.loglevel,
 181                                         (*probe_desc->event_desc[i]->loglevel)->identifier,
 182                                         LTTNG_UST_SYM_NAME_LEN);
 183                                 list_entry->tp.loglevel[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 184                                 list_entry->tp.loglevel_value =
 185                                         (*probe_desc->event_desc[i]->loglevel)->value;
 186                         }
 187                 }
 188         }
 189         if (cds_list_empty(&list->head))
 190                 list->iter = NULL;
 191         else
 192                 list->iter =
 193                         cds_list_first_entry(&list->head, struct tp_list_entry, head);
 194         return 0;
 195
 196 err_nomem:
 197         ltt_probes_prune_event_list(list);
 198         return -ENOMEM;
 199 }
 200
 201 /*
 202  * Return current iteration position, advance internal iterator to next.
 203  * Return NULL if end of list.
 204  */
 205 struct lttng_ust_tracepoint_iter *
 206         lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
 207 {
 208         struct tp_list_entry *entry;
 209
 210         if (!list->iter)
 211                 return NULL;
 212         entry = list->iter;
 213         if (entry->head.next == &list->head)
 214                 list->iter = NULL;
 215         else
 216                 list->iter = cds_list_entry(entry->head.next,
 217                                 struct tp_list_entry, head);
 218         return &entry->tp;
 219 }
 220
 221 /*
 222  * Get loglevel if the loglevel is present in the loglevel hash table.
 223  * Must be called with ust lock held.
 224  * Returns NULL if not present.
 225  */
 226 struct loglevel_entry *get_loglevel(const char *name)
 227 {
 228         struct cds_hlist_head *head;
 229         struct cds_hlist_node *node;
 230         struct loglevel_entry *e;
 231         size_t name_len = strlen(name);
 232         uint32_t hash;
 233
 234         if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) {
 235                 WARN("Truncating loglevel name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1);
 236                 name_len = LTTNG_UST_SYM_NAME_LEN - 1;
 237         }
 238         hash = jhash(name, name_len, 0);
 239         head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)];
 240         cds_hlist_for_each_entry(e, node, head, hlist) {
 241                 if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1))
 242                         return e;
 243         }
 244         return NULL;
 245 }
 246
 247 struct loglevel_entry *get_loglevel_value(int64_t value)
 248 {
 249         char name[LTTNG_UST_SYM_NAME_LEN];
 250         int ret;
 251
 252         ret = snprintf(name, LTTNG_UST_SYM_NAME_LEN, "%lld", (long long) value);
 253         if (ret < 0)
 254                 return NULL;
 255         return get_loglevel(name);
 256 }
 257
 258 /*
 259  * marshall all probes/all events and create those that fit the
 260  * loglevel. Add them to the events list as created.
 261  */
 262 static
 263 void _probes_create_loglevel_events(struct loglevel_entry *entry,
 264                                 struct session_loglevel *loglevel)
 265 {
 266         struct lttng_probe_desc *probe_desc;
 267         struct lttng_ust_event event_param;
 268         int i;
 269
 270         cds_list_for_each_entry(probe_desc, &probe_list, head) {
 271                 for (i = 0; i < probe_desc->nr_events; i++) {
 272                         const struct tracepoint_loglevel_entry *ev_ll;
 273                         const struct lttng_event_desc *event_desc;
 274                         int match = 0;
 275
 276                         event_desc = probe_desc->event_desc[i];
 277                         if (!(event_desc->loglevel))
 278                                 continue;
 279                         ev_ll = *event_desc->loglevel;
 280                         if (isdigit(entry->name[0])) {
 281                                 if (atoll(entry->name) == ev_ll->value) {
 282                                         match = 1;
 283                                 }
 284                         } else if (!strncmp(ev_ll->identifier, entry->name,
 285                                         LTTNG_UST_SYM_NAME_LEN - 1)) {
 286                                 match = 1;
 287                         }
 288
 289                         if (match) {
 290                                 struct ltt_event *ev;
 291                                 int ret;
 292
 293                                 memcpy(&event_param, &loglevel->event_param,
 294                                                 sizeof(event_param));
 295                                 memcpy(event_param.name,
 296                                         event_desc->name,
 297                                         sizeof(event_param.name));
 298                                 /* create event */
 299                                 ret = ltt_event_create(loglevel->chan,
 300                                         &event_param, NULL,
 301                                         &ev);
 302                                 if (ret) {
 303                                         DBG("Error creating event");
 304                                         continue;
 305                                 }
 306                                 cds_list_add(&ev->loglevel_list,
 307                                         &loglevel->events);
 308                         }
 309                 }
 310         }
 311 }
 312
 313 /*
 314  * Add the loglevel to the loglevel hash table. Must be called with
 315  * ust lock held.
 316  */
 317 struct session_loglevel *add_loglevel(const char *name,
 318         struct ltt_channel *chan,
 319         struct lttng_ust_event *event_param)
 320 {
 321         struct cds_hlist_head *head;
 322         struct cds_hlist_node *node;
 323         struct loglevel_entry *e;
 324         struct session_loglevel *sl;
 325         int found = 0;
 326         size_t name_len = strlen(name);
 327         uint32_t hash;
 328
 329         if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) {
 330                 WARN("Truncating loglevel name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1);
 331                 name_len = LTTNG_UST_SYM_NAME_LEN - 1;
 332         }
 333         hash = jhash(name, name_len, 0);
 334         /* loglevel entry */
 335         head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)];
 336         cds_hlist_for_each_entry(e, node, head, hlist) {
 337                 if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) {
 338                         found = 1;
 339                         break;
 340                 }
 341         }
 342
 343         if (!found) {
 344                 /*
 345                  * Using zmalloc here to allocate a variable length element. Could
 346                  * cause some memory fragmentation if overused.
 347                  */
 348                 e = zmalloc(sizeof(struct loglevel_entry) + name_len + 1);
 349                 if (!e)
 350                         return ERR_PTR(-ENOMEM);
 351                 memcpy(&e->name[0], name, name_len + 1);
 352                 e->name[name_len] = '\0';
 353                 cds_hlist_add_head(&e->hlist, head);
 354                 CDS_INIT_LIST_HEAD(&e->session_list);
 355         }
 356
 357         /* session loglevel */
 358         cds_list_for_each_entry(sl, &e->session_list, session_list) {
 359                 if (chan == sl->chan) {
 360                         DBG("loglevel %s busy for this channel", name);
 361                         return ERR_PTR(-EEXIST);        /* Already there */
 362                 }
 363         }
 364         sl = zmalloc(sizeof(struct session_loglevel));
 365         if (!sl)
 366                 return ERR_PTR(-ENOMEM);
 367         sl->chan = chan;
 368         sl->enabled = 1;
 369         memcpy(&sl->event_param, event_param, sizeof(sl->event_param));
 370         sl->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
 371         CDS_INIT_LIST_HEAD(&sl->events);
 372         cds_list_add(&sl->list, &chan->session->loglevels);
 373         cds_list_add(&sl->session_list, &e->session_list);
 374         sl->entry = e;
 375         _probes_create_loglevel_events(e, sl);
 376         return sl;
 377 }
 378
 379 /*
 380  * Remove the loglevel from the loglevel hash table. Must be called with
 381  * ust_lock held. Only called at session teardown.
 382  */
 383 void _remove_loglevel(struct session_loglevel *loglevel)
 384 {
 385         struct ltt_event *ev, *tmp;
 386
 387         /*
 388          * Just remove the events owned (for enable/disable) by this
 389          * loglevel from the list. The session teardown will take care
 390          * of freeing the event memory.
 391          */
 392         cds_list_for_each_entry_safe(ev, tmp, &loglevel->events,
 393                         loglevel_list) {
 394                 cds_list_del(&ev->loglevel_list);
 395         }
 396         cds_list_del(&loglevel->session_list);
 397         cds_list_del(&loglevel->list);
 398         if (cds_list_empty(&loglevel->entry->session_list)) {
 399                 cds_hlist_del(&loglevel->entry->hlist);
 400                 free(loglevel->entry);
 401         }
 402         free(loglevel);
 403 }
 404
 405 int ltt_loglevel_enable(struct session_loglevel *loglevel)
 406 {
 407         struct ltt_event *ev;
 408         int ret;
 409
 410         if (loglevel->enabled)
 411                 return -EEXIST;
 412         cds_list_for_each_entry(ev, &loglevel->events, loglevel_list) {
 413                 ret = ltt_event_enable(ev);
 414                 if (ret) {
 415                         DBG("Error: enable error.\n");
 416                         return ret;
 417                 }
 418         }
 419         loglevel->enabled = 1;
 420         return 0;
 421 }
 422
 423 int ltt_loglevel_disable(struct session_loglevel *loglevel)
 424 {
 425         struct ltt_event *ev;
 426         int ret;
 427
 428         if (!loglevel->enabled)
 429                 return -EEXIST;
 430         cds_list_for_each_entry(ev, &loglevel->events, loglevel_list) {
 431                 ret = ltt_event_disable(ev);
 432                 if (ret) {
 433                         DBG("Error: disable error.\n");
 434                         return ret;
 435                 }
 436         }
 437         loglevel->enabled = 0;
 438         return 0;
 439 }
 440
 441 /* WILDCARDS */
 442
 443 /*
 444  * Return wildcard for a given event name if the event name match the
 445  * one of the wildcards.
 446  * Must be called with ust lock held.
 447  * Returns NULL if not present.
 448  */
 449 struct wildcard_entry *match_wildcard(const char *name)
 450 {
 451         struct wildcard_entry *e;
 452
 453         cds_list_for_each_entry(e, &wildcard_list, list) {
 454                 /* If only contain '*' */
 455                 if (strlen(e->name) == 1)
 456                         return e;
 457                 /* Compare excluding final '*' */
 458                 if (!strncmp(name, e->name, strlen(e->name) - 1))
 459                         return e;
 460         }
 461         return NULL;
 462 }
 463
 464 /*
 465  * marshall all probes/all events and create those that fit the
 466  * wildcard. Add them to the events list as created.
 467  */
 468 static
 469 void _probes_create_wildcard_events(struct wildcard_entry *entry,
 470                                 struct session_wildcard *wildcard)
 471 {
 472         struct lttng_probe_desc *probe_desc;
 473         struct lttng_ust_event event_param;
 474         int i;
 475
 476         cds_list_for_each_entry(probe_desc, &probe_list, head) {
 477                 for (i = 0; i < probe_desc->nr_events; i++) {
 478                         const struct lttng_event_desc *event_desc;
 479                         int match = 0;
 480
 481                         event_desc = probe_desc->event_desc[i];
 482                         /* compare excluding final '*' */
 483                         assert(strlen(entry->name) > 0);
 484                         if (strcmp(event_desc->name, "lttng_ust:metadata")
 485                                         && (strlen(entry->name) == 1
 486                                                 || !strncmp(event_desc->name, entry->name,
 487                                                         strlen(entry->name) - 1))) {
 488                                 match = 1;
 489                         }
 490                         if (match) {
 491                                 struct ltt_event *ev;
 492                                 int ret;
 493
 494                                 memcpy(&event_param, &wildcard->event_param,
 495                                                 sizeof(event_param));
 496                                 memcpy(event_param.name,
 497                                         event_desc->name,
 498                                         sizeof(event_param.name));
 499                                 /* create event */
 500                                 ret = ltt_event_create(wildcard->chan,
 501                                         &event_param, NULL,
 502                                         &ev);
 503                                 if (ret) {
 504                                         DBG("Error creating event");
 505                                         continue;
 506                                 }
 507                                 cds_list_add(&ev->wildcard_list,
 508                                         &wildcard->events);
 509                         }
 510                 }
 511         }
 512 }
 513
 514 /*
 515  * Add the wildcard to the wildcard hash table. Must be called with
 516  * ust lock held.
 517  */
 518 struct session_wildcard *add_wildcard(const char *name,
 519         struct ltt_channel *chan,
 520         struct lttng_ust_event *event_param)
 521 {
 522         struct wildcard_entry *e;
 523         struct session_wildcard *sw;
 524         size_t name_len = strlen(name) + 1;
 525         int found = 0;
 526
 527         /* wildcard entry */
 528         cds_list_for_each_entry(e, &wildcard_list, list) {
 529                 if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) {
 530                         found = 1;
 531                         break;
 532                 }
 533         }
 534
 535         if (!found) {
 536                 /*
 537                  * Using zmalloc here to allocate a variable length element. Could
 538                  * cause some memory fragmentation if overused.
 539                  */
 540                 e = zmalloc(sizeof(struct wildcard_entry) + name_len);
 541                 if (!e)
 542                         return ERR_PTR(-ENOMEM);
 543                 memcpy(&e->name[0], name, name_len);
 544                 cds_list_add(&e->list, &wildcard_list);
 545                 CDS_INIT_LIST_HEAD(&e->session_list);
 546         }
 547
 548         /* session wildcard */
 549         cds_list_for_each_entry(sw, &e->session_list, session_list) {
 550                 if (chan == sw->chan) {
 551                         DBG("wildcard %s busy for this channel", name);
 552                         return ERR_PTR(-EEXIST);        /* Already there */
 553                 }
 554         }
 555         sw = zmalloc(sizeof(struct session_wildcard));
 556         if (!sw)
 557                 return ERR_PTR(-ENOMEM);
 558         sw->chan = chan;
 559         sw->enabled = 1;
 560         memcpy(&sw->event_param, event_param, sizeof(sw->event_param));
 561         sw->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
 562         CDS_INIT_LIST_HEAD(&sw->events);
 563         cds_list_add(&sw->list, &chan->session->wildcards);
 564         cds_list_add(&sw->session_list, &e->session_list);
 565         sw->entry = e;
 566         _probes_create_wildcard_events(e, sw);
 567         return sw;
 568 }
 569
 570 /*
 571  * Remove the wildcard from the wildcard hash table. Must be called with
 572  * ust_lock held. Only called at session teardown.
 573  */
 574 void _remove_wildcard(struct session_wildcard *wildcard)
 575 {
 576         struct ltt_event *ev, *tmp;
 577
 578         /*
 579          * Just remove the events owned (for enable/disable) by this
 580          * wildcard from the list. The session teardown will take care
 581          * of freeing the event memory.
 582          */
 583         cds_list_for_each_entry_safe(ev, tmp, &wildcard->events,
 584                         wildcard_list) {
 585                 cds_list_del(&ev->wildcard_list);
 586         }
 587         cds_list_del(&wildcard->session_list);
 588         cds_list_del(&wildcard->list);
 589         if (cds_list_empty(&wildcard->entry->session_list)) {
 590                 cds_list_del(&wildcard->entry->list);
 591                 free(wildcard->entry);
 592         }
 593         free(wildcard);
 594 }
 595
 596 int ltt_wildcard_enable(struct session_wildcard *wildcard)
 597 {
 598         struct ltt_event *ev;
 599         int ret;
 600
 601         if (wildcard->enabled)
 602                 return -EEXIST;
 603         cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
 604                 ret = ltt_event_enable(ev);
 605                 if (ret) {
 606                         DBG("Error: enable error.\n");
 607                         return ret;
 608                 }
 609         }
 610         wildcard->enabled = 1;
 611         return 0;
 612 }
 613
 614 int ltt_wildcard_disable(struct session_wildcard *wildcard)
 615 {
 616         struct ltt_event *ev;
 617         int ret;
 618
 619         if (!wildcard->enabled)
 620                 return -EEXIST;
 621         cds_list_for_each_entry(ev, &wildcard->events, wildcard_list) {
 622                 ret = ltt_event_disable(ev);
 623                 if (ret) {
 624                         DBG("Error: disable error.\n");
 625                         return ret;
 626                 }
 627         }
 628         wildcard->enabled = 0;
 629         return 0;
 630 }