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