src/bin/lttng-sessiond/trace-kernel.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #include <common/common.h>
  25 #include <common/defaults.h>
  26
  27 #include "consumer.h"
  28 #include "trace-kernel.h"
  29
  30 /*
  31  * Find the channel name for the given kernel session.
  32  */
  33 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
  34                 char *name, struct ltt_kernel_session *session)
  35 {
  36         struct ltt_kernel_channel *chan;
  37
  38         assert(session);
  39         assert(name);
  40
  41         /*
  42          * If we receive an empty string for channel name, it means the
  43          * default channel name is requested.
  44          */
  45         if (name[0] == '\0')
  46                 name = DEFAULT_CHANNEL_NAME;
  47
  48         DBG("Trying to find channel %s", name);
  49
  50         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  51                 if (strcmp(name, chan->channel->name) == 0) {
  52                         DBG("Found channel by name %s", name);
  53                         return chan;
  54                 }
  55         }
  56
  57         return NULL;
  58 }
  59
  60 /*
  61  * Find the event for the given channel.
  62  */
  63 struct ltt_kernel_event *trace_kernel_find_event(
  64                 char *name, struct ltt_kernel_channel *channel,
  65                 enum lttng_event_type type,
  66                 struct lttng_filter_bytecode *filter)
  67 {
  68         struct ltt_kernel_event *ev;
  69         int found = 0;
  70
  71         assert(name);
  72         assert(channel);
  73
  74         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  75                 if (type != LTTNG_EVENT_ALL && ev->type != type) {
  76                         continue;
  77                 }
  78                 if (strcmp(name, ev->event->name)) {
  79                         continue;
  80                 }
  81                 if ((ev->filter && !filter) || (!ev->filter && filter)) {
  82                         continue;
  83                 }
  84                 if (ev->filter && filter) {
  85                         if (ev->filter->len != filter->len ||
  86                                         memcmp(ev->filter->data, filter->data,
  87                                                 filter->len) != 0) {
  88                                 continue;
  89                         }
  90                 }
  91                 found = 1;
  92                 break;
  93         }
  94         if (found) {
  95                 DBG("Found event %s for channel %s", name,
  96                         channel->channel->name);
  97                 return ev;
  98         } else {
  99                 return NULL;
 100         }
 101 }
 102
 103 /*
 104  * Find the event name for the given channel.
 105  */
 106 struct ltt_kernel_event *trace_kernel_get_event_by_name(
 107                 char *name, struct ltt_kernel_channel *channel,
 108                 enum lttng_event_type type)
 109 {
 110         struct ltt_kernel_event *ev;
 111         int found = 0;
 112
 113         assert(name);
 114         assert(channel);
 115
 116         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
 117                 if (type != LTTNG_EVENT_ALL && ev->type != type) {
 118                         continue;
 119                 }
 120                 if (strcmp(name, ev->event->name)) {
 121                         continue;
 122                 }
 123                 found = 1;
 124                 break;
 125         }
 126         if (found) {
 127                 DBG("Found event %s for channel %s", name,
 128                         channel->channel->name);
 129                 return ev;
 130         } else {
 131                 return NULL;
 132         }
 133 }
 134
 135 /*
 136  * Allocate and initialize a kernel session data structure.
 137  *
 138  * Return pointer to structure or NULL.
 139  */
 140 struct ltt_kernel_session *trace_kernel_create_session(void)
 141 {
 142         struct ltt_kernel_session *lks = NULL;
 143
 144         /* Allocate a new ltt kernel session */
 145         lks = zmalloc(sizeof(struct ltt_kernel_session));
 146         if (lks == NULL) {
 147                 PERROR("create kernel session zmalloc");
 148                 goto alloc_error;
 149         }
 150
 151         /* Init data structure */
 152         lks->fd = -1;
 153         lks->metadata_stream_fd = -1;
 154         lks->channel_count = 0;
 155         lks->stream_count_global = 0;
 156         lks->metadata = NULL;
 157         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 158
 159         lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 160         if (lks->consumer == NULL) {
 161                 goto error;
 162         }
 163
 164         return lks;
 165
 166 error:
 167         free(lks);
 168
 169 alloc_error:
 170         return NULL;
 171 }
 172
 173 /*
 174  * Allocate and initialize a kernel channel data structure.
 175  *
 176  * Return pointer to structure or NULL.
 177  */
 178 struct ltt_kernel_channel *trace_kernel_create_channel(
 179                 struct lttng_channel *chan)
 180 {
 181         struct ltt_kernel_channel *lkc;
 182
 183         assert(chan);
 184
 185         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 186         if (lkc == NULL) {
 187                 PERROR("ltt_kernel_channel zmalloc");
 188                 goto error;
 189         }
 190
 191         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 192         if (lkc->channel == NULL) {
 193                 PERROR("lttng_channel zmalloc");
 194                 free(lkc);
 195                 goto error;
 196         }
 197         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 198
 199         /*
 200          * If we receive an empty string for channel name, it means the
 201          * default channel name is requested.
 202          */
 203         if (chan->name[0] == '\0') {
 204                 strncpy(lkc->channel->name, DEFAULT_CHANNEL_NAME,
 205                         sizeof(lkc->channel->name));
 206         }
 207         lkc->channel->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 208
 209         lkc->fd = -1;
 210         lkc->stream_count = 0;
 211         lkc->event_count = 0;
 212         lkc->enabled = 1;
 213         /* Init linked list */
 214         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 215         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 216         CDS_INIT_LIST_HEAD(&lkc->ctx_list);
 217
 218         return lkc;
 219
 220 error:
 221         return NULL;
 222 }
 223
 224 /*
 225  * Allocate and init a kernel context object.
 226  *
 227  * Return the allocated object or NULL on error.
 228  */
 229 struct ltt_kernel_context *trace_kernel_create_context(
 230                 struct lttng_kernel_context *ctx)
 231 {
 232         struct ltt_kernel_context *kctx;
 233
 234         kctx = zmalloc(sizeof(*kctx));
 235         if (!kctx) {
 236                 PERROR("zmalloc kernel context");
 237                 goto error;
 238         }
 239
 240         if (ctx) {
 241                 memcpy(&kctx->ctx, ctx, sizeof(kctx->ctx));
 242         }
 243 error:
 244         return kctx;
 245 }
 246
 247 /*
 248  * Allocate and init a kernel context object from an existing kernel context
 249  * object.
 250  *
 251  * Return the allocated object or NULL on error.
 252  */
 253 struct ltt_kernel_context *trace_kernel_copy_context(
 254                 struct ltt_kernel_context *kctx)
 255 {
 256         struct ltt_kernel_context *kctx_copy;
 257
 258         assert(kctx);
 259         kctx_copy = zmalloc(sizeof(*kctx_copy));
 260         if (!kctx_copy) {
 261                 PERROR("zmalloc ltt_kernel_context");
 262                 goto error;
 263         }
 264
 265         memcpy(kctx_copy, kctx, sizeof(*kctx_copy));
 266         memset(&kctx_copy->list, 0, sizeof(kctx_copy->list));
 267
 268 error:
 269         return kctx_copy;
 270 }
 271
 272 /*
 273  * Allocate and initialize a kernel event. Set name and event type.
 274  * We own filter_expression, and filter.
 275  *
 276  * Return pointer to structure or NULL.
 277  */
 278 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev,
 279                 char *filter_expression, struct lttng_filter_bytecode *filter)
 280 {
 281         struct ltt_kernel_event *lke;
 282         struct lttng_kernel_event *attr;
 283
 284         assert(ev);
 285
 286         lke = zmalloc(sizeof(struct ltt_kernel_event));
 287         attr = zmalloc(sizeof(struct lttng_kernel_event));
 288         if (lke == NULL || attr == NULL) {
 289                 PERROR("kernel event zmalloc");
 290                 goto error;
 291         }
 292
 293         switch (ev->type) {
 294         case LTTNG_EVENT_PROBE:
 295                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 296                 attr->u.kprobe.addr = ev->attr.probe.addr;
 297                 attr->u.kprobe.offset = ev->attr.probe.offset;
 298                 strncpy(attr->u.kprobe.symbol_name,
 299                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 300                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 301                 break;
 302         case LTTNG_EVENT_FUNCTION:
 303                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 304                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 305                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 306                 strncpy(attr->u.kretprobe.symbol_name,
 307                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 308                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 309                 break;
 310         case LTTNG_EVENT_FUNCTION_ENTRY:
 311                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 312                 strncpy(attr->u.ftrace.symbol_name,
 313                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 314                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 315                 break;
 316         case LTTNG_EVENT_TRACEPOINT:
 317                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 318                 break;
 319         case LTTNG_EVENT_SYSCALL:
 320                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 321                 break;
 322         case LTTNG_EVENT_ALL:
 323                 attr->instrumentation = LTTNG_KERNEL_ALL;
 324                 break;
 325         default:
 326                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 327                 goto error;
 328         }
 329
 330         /* Copy event name */
 331         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 332         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 333
 334         /* Setting up a kernel event */
 335         lke->fd = -1;
 336         lke->event = attr;
 337         lke->enabled = 1;
 338         lke->filter_expression = filter_expression;
 339         lke->filter = filter;
 340
 341         return lke;
 342
 343 error:
 344         free(filter_expression);
 345         free(filter);
 346         free(lke);
 347         free(attr);
 348         return NULL;
 349 }
 350
 351 /*
 352  * Allocate and initialize a kernel metadata.
 353  *
 354  * Return pointer to structure or NULL.
 355  */
 356 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 357 {
 358         struct ltt_kernel_metadata *lkm;
 359         struct lttng_channel *chan;
 360
 361         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 362         chan = zmalloc(sizeof(struct lttng_channel));
 363         if (lkm == NULL || chan == NULL) {
 364                 PERROR("kernel metadata zmalloc");
 365                 goto error;
 366         }
 367
 368         /* Set default attributes */
 369         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 370         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 371         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 372         chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
 373         chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
 374         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 375
 376         /* Init metadata */
 377         lkm->fd = -1;
 378         lkm->conf = chan;
 379
 380         return lkm;
 381
 382 error:
 383         free(lkm);
 384         free(chan);
 385         return NULL;
 386 }
 387
 388 /*
 389  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 390  * default.
 391  *
 392  * Return pointer to structure or NULL.
 393  */
 394 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 395                 unsigned int count)
 396 {
 397         int ret;
 398         struct ltt_kernel_stream *lks;
 399
 400         assert(name);
 401
 402         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 403         if (lks == NULL) {
 404                 PERROR("kernel stream zmalloc");
 405                 goto error;
 406         }
 407
 408         /* Set name */
 409         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 410         if (ret < 0) {
 411                 PERROR("snprintf stream name");
 412                 goto error;
 413         }
 414         lks->name[sizeof(lks->name) - 1] = '\0';
 415
 416         /* Init stream */
 417         lks->fd = -1;
 418         lks->state = 0;
 419         lks->cpu = count;
 420
 421         return lks;
 422
 423 error:
 424         return NULL;
 425 }
 426
 427 /*
 428  * Cleanup kernel stream structure.
 429  */
 430 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 431 {
 432         assert(stream);
 433
 434         DBG("[trace] Closing stream fd %d", stream->fd);
 435         /* Close kernel fd */
 436         if (stream->fd >= 0) {
 437                 int ret;
 438
 439                 ret = close(stream->fd);
 440                 if (ret) {
 441                         PERROR("close");
 442                 }
 443         }
 444         /* Remove from stream list */
 445         cds_list_del(&stream->list);
 446
 447         free(stream);
 448 }
 449
 450 /*
 451  * Cleanup kernel event structure.
 452  */
 453 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 454 {
 455         assert(event);
 456
 457         if (event->fd >= 0) {
 458                 int ret;
 459
 460                 DBG("[trace] Closing event fd %d", event->fd);
 461                 /* Close kernel fd */
 462                 ret = close(event->fd);
 463                 if (ret) {
 464                         PERROR("close");
 465                 }
 466         } else {
 467                 DBG("[trace] Tearing down event (no associated fd)");
 468         }
 469
 470         /* Remove from event list */
 471         cds_list_del(&event->list);
 472
 473         free(event->filter_expression);
 474         free(event->filter);
 475
 476         free(event->event);
 477         free(event);
 478 }
 479
 480 /*
 481  * Cleanup kernel context structure.
 482  */
 483 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 484 {
 485         assert(ctx);
 486
 487         if (ctx->in_list) {
 488                 cds_list_del(&ctx->list);
 489         }
 490         free(ctx);
 491 }
 492
 493 /*
 494  * Cleanup kernel channel structure.
 495  */
 496 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 497 {
 498         struct ltt_kernel_stream *stream, *stmp;
 499         struct ltt_kernel_event *event, *etmp;
 500         struct ltt_kernel_context *ctx, *ctmp;
 501         int ret;
 502
 503         assert(channel);
 504
 505         DBG("[trace] Closing channel fd %d", channel->fd);
 506         /* Close kernel fd */
 507         if (channel->fd >= 0) {
 508                 ret = close(channel->fd);
 509                 if (ret) {
 510                         PERROR("close");
 511                 }
 512         }
 513
 514         /* For each stream in the channel list */
 515         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 516                 trace_kernel_destroy_stream(stream);
 517         }
 518
 519         /* For each event in the channel list */
 520         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 521                 trace_kernel_destroy_event(event);
 522         }
 523
 524         /* For each context in the channel list */
 525         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 526                 trace_kernel_destroy_context(ctx);
 527         }
 528
 529         /* Remove from channel list */
 530         cds_list_del(&channel->list);
 531
 532         free(channel->channel);
 533         free(channel);
 534 }
 535
 536 /*
 537  * Cleanup kernel metadata structure.
 538  */
 539 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 540 {
 541         assert(metadata);
 542
 543         DBG("[trace] Closing metadata fd %d", metadata->fd);
 544         /* Close kernel fd */
 545         if (metadata->fd >= 0) {
 546                 int ret;
 547
 548                 ret = close(metadata->fd);
 549                 if (ret) {
 550                         PERROR("close");
 551                 }
 552         }
 553
 554         free(metadata->conf);
 555         free(metadata);
 556 }
 557
 558 /*
 559  * Cleanup kernel session structure
 560  *
 561  * Should *NOT* be called with RCU read-side lock held.
 562  */
 563 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 564 {
 565         struct ltt_kernel_channel *channel, *ctmp;
 566         int ret;
 567
 568         assert(session);
 569
 570         DBG("[trace] Closing session fd %d", session->fd);
 571         /* Close kernel fds */
 572         if (session->fd >= 0) {
 573                 ret = close(session->fd);
 574                 if (ret) {
 575                         PERROR("close");
 576                 }
 577         }
 578
 579         if (session->metadata_stream_fd >= 0) {
 580                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 581                 ret = close(session->metadata_stream_fd);
 582                 if (ret) {
 583                         PERROR("close");
 584                 }
 585         }
 586
 587         if (session->metadata != NULL) {
 588                 trace_kernel_destroy_metadata(session->metadata);
 589         }
 590
 591         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 592                 trace_kernel_destroy_channel(channel);
 593         }
 594
 595         /* Wipe consumer output object */
 596         consumer_output_put(session->consumer);
 597
 598         free(session);
 599 }