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
 244         CDS_INIT_LIST_HEAD(&kctx->list);
 245
 246 error:
 247         return kctx;
 248 }
 249
 250 /*
 251  * Allocate and initialize a kernel event. Set name and event type.
 252  * We own filter_expression, and filter.
 253  *
 254  * Return pointer to structure or NULL.
 255  */
 256 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev,
 257                 char *filter_expression, struct lttng_filter_bytecode *filter)
 258 {
 259         struct ltt_kernel_event *lke;
 260         struct lttng_kernel_event *attr;
 261
 262         assert(ev);
 263
 264         lke = zmalloc(sizeof(struct ltt_kernel_event));
 265         attr = zmalloc(sizeof(struct lttng_kernel_event));
 266         if (lke == NULL || attr == NULL) {
 267                 PERROR("kernel event zmalloc");
 268                 goto error;
 269         }
 270
 271         switch (ev->type) {
 272         case LTTNG_EVENT_PROBE:
 273                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 274                 attr->u.kprobe.addr = ev->attr.probe.addr;
 275                 attr->u.kprobe.offset = ev->attr.probe.offset;
 276                 strncpy(attr->u.kprobe.symbol_name,
 277                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 278                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 279                 break;
 280         case LTTNG_EVENT_FUNCTION:
 281                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 282                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 283                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 284                 strncpy(attr->u.kretprobe.symbol_name,
 285                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 286                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 287                 break;
 288         case LTTNG_EVENT_FUNCTION_ENTRY:
 289                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 290                 strncpy(attr->u.ftrace.symbol_name,
 291                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 292                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 293                 break;
 294         case LTTNG_EVENT_TRACEPOINT:
 295                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 296                 break;
 297         case LTTNG_EVENT_SYSCALL:
 298                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 299                 break;
 300         case LTTNG_EVENT_ALL:
 301                 attr->instrumentation = LTTNG_KERNEL_ALL;
 302                 break;
 303         default:
 304                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 305                 goto error;
 306         }
 307
 308         /* Copy event name */
 309         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 310         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 311
 312         /* Setting up a kernel event */
 313         lke->fd = -1;
 314         lke->event = attr;
 315         lke->enabled = 1;
 316         lke->filter_expression = filter_expression;
 317         lke->filter = filter;
 318
 319         return lke;
 320
 321 error:
 322         free(filter_expression);
 323         free(filter);
 324         free(lke);
 325         free(attr);
 326         return NULL;
 327 }
 328
 329 /*
 330  * Allocate and initialize a kernel metadata.
 331  *
 332  * Return pointer to structure or NULL.
 333  */
 334 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 335 {
 336         struct ltt_kernel_metadata *lkm;
 337         struct lttng_channel *chan;
 338
 339         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 340         chan = zmalloc(sizeof(struct lttng_channel));
 341         if (lkm == NULL || chan == NULL) {
 342                 PERROR("kernel metadata zmalloc");
 343                 goto error;
 344         }
 345
 346         /* Set default attributes */
 347         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 348         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 349         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 350         chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
 351         chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
 352         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 353
 354         /* Init metadata */
 355         lkm->fd = -1;
 356         lkm->conf = chan;
 357
 358         return lkm;
 359
 360 error:
 361         free(lkm);
 362         free(chan);
 363         return NULL;
 364 }
 365
 366 /*
 367  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 368  * default.
 369  *
 370  * Return pointer to structure or NULL.
 371  */
 372 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 373                 unsigned int count)
 374 {
 375         int ret;
 376         struct ltt_kernel_stream *lks;
 377
 378         assert(name);
 379
 380         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 381         if (lks == NULL) {
 382                 PERROR("kernel stream zmalloc");
 383                 goto error;
 384         }
 385
 386         /* Set name */
 387         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 388         if (ret < 0) {
 389                 PERROR("snprintf stream name");
 390                 goto error;
 391         }
 392         lks->name[sizeof(lks->name) - 1] = '\0';
 393
 394         /* Init stream */
 395         lks->fd = -1;
 396         lks->state = 0;
 397         lks->cpu = count;
 398
 399         return lks;
 400
 401 error:
 402         return NULL;
 403 }
 404
 405 /*
 406  * Cleanup kernel stream structure.
 407  */
 408 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 409 {
 410         assert(stream);
 411
 412         DBG("[trace] Closing stream fd %d", stream->fd);
 413         /* Close kernel fd */
 414         if (stream->fd >= 0) {
 415                 int ret;
 416
 417                 ret = close(stream->fd);
 418                 if (ret) {
 419                         PERROR("close");
 420                 }
 421         }
 422         /* Remove from stream list */
 423         cds_list_del(&stream->list);
 424
 425         free(stream);
 426 }
 427
 428 /*
 429  * Cleanup kernel event structure.
 430  */
 431 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 432 {
 433         assert(event);
 434
 435         if (event->fd >= 0) {
 436                 int ret;
 437
 438                 DBG("[trace] Closing event fd %d", event->fd);
 439                 /* Close kernel fd */
 440                 ret = close(event->fd);
 441                 if (ret) {
 442                         PERROR("close");
 443                 }
 444         } else {
 445                 DBG("[trace] Tearing down event (no associated fd)");
 446         }
 447
 448         /* Remove from event list */
 449         cds_list_del(&event->list);
 450
 451         free(event->filter_expression);
 452         free(event->filter);
 453
 454         free(event->event);
 455         free(event);
 456 }
 457
 458 /*
 459  * Cleanup kernel context structure.
 460  */
 461 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 462 {
 463         assert(ctx);
 464
 465         cds_list_del(&ctx->list);
 466         free(ctx);
 467 }
 468
 469 /*
 470  * Cleanup kernel channel structure.
 471  */
 472 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 473 {
 474         struct ltt_kernel_stream *stream, *stmp;
 475         struct ltt_kernel_event *event, *etmp;
 476         struct ltt_kernel_context *ctx, *ctmp;
 477         int ret;
 478
 479         assert(channel);
 480
 481         DBG("[trace] Closing channel fd %d", channel->fd);
 482         /* Close kernel fd */
 483         if (channel->fd >= 0) {
 484                 ret = close(channel->fd);
 485                 if (ret) {
 486                         PERROR("close");
 487                 }
 488         }
 489
 490         /* For each stream in the channel list */
 491         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 492                 trace_kernel_destroy_stream(stream);
 493         }
 494
 495         /* For each event in the channel list */
 496         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 497                 trace_kernel_destroy_event(event);
 498         }
 499
 500         /* For each context in the channel list */
 501         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 502                 trace_kernel_destroy_context(ctx);
 503         }
 504
 505         /* Remove from channel list */
 506         cds_list_del(&channel->list);
 507
 508         free(channel->channel);
 509         free(channel);
 510 }
 511
 512 /*
 513  * Cleanup kernel metadata structure.
 514  */
 515 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 516 {
 517         assert(metadata);
 518
 519         DBG("[trace] Closing metadata fd %d", metadata->fd);
 520         /* Close kernel fd */
 521         if (metadata->fd >= 0) {
 522                 int ret;
 523
 524                 ret = close(metadata->fd);
 525                 if (ret) {
 526                         PERROR("close");
 527                 }
 528         }
 529
 530         free(metadata->conf);
 531         free(metadata);
 532 }
 533
 534 /*
 535  * Cleanup kernel session structure
 536  *
 537  * Should *NOT* be called with RCU read-side lock held.
 538  */
 539 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 540 {
 541         struct ltt_kernel_channel *channel, *ctmp;
 542         int ret;
 543
 544         assert(session);
 545
 546         DBG("[trace] Closing session fd %d", session->fd);
 547         /* Close kernel fds */
 548         if (session->fd >= 0) {
 549                 ret = close(session->fd);
 550                 if (ret) {
 551                         PERROR("close");
 552                 }
 553         }
 554
 555         if (session->metadata_stream_fd >= 0) {
 556                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 557                 ret = close(session->metadata_stream_fd);
 558                 if (ret) {
 559                         PERROR("close");
 560                 }
 561         }
 562
 563         if (session->metadata != NULL) {
 564                 trace_kernel_destroy_metadata(session->metadata);
 565         }
 566
 567         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 568                 trace_kernel_destroy_channel(channel);
 569         }
 570
 571         /* Wipe consumer output object */
 572         consumer_output_put(session->consumer);
 573
 574         free(session);
 575 }