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         return lks;
 166
 167 error:
 168         free(lks);
 169
 170 alloc_error:
 171         return NULL;
 172 }
 173
 174 /*
 175  * Allocate and initialize a kernel channel data structure.
 176  *
 177  * Return pointer to structure or NULL.
 178  */
 179 struct ltt_kernel_channel *trace_kernel_create_channel(
 180                 struct lttng_channel *chan)
 181 {
 182         struct ltt_kernel_channel *lkc;
 183
 184         assert(chan);
 185
 186         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 187         if (lkc == NULL) {
 188                 PERROR("ltt_kernel_channel zmalloc");
 189                 goto error;
 190         }
 191
 192         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 193         if (lkc->channel == NULL) {
 194                 PERROR("lttng_channel zmalloc");
 195                 free(lkc);
 196                 goto error;
 197         }
 198         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 199
 200         /*
 201          * If we receive an empty string for channel name, it means the
 202          * default channel name is requested.
 203          */
 204         if (chan->name[0] == '\0') {
 205                 strncpy(lkc->channel->name, DEFAULT_CHANNEL_NAME,
 206                         sizeof(lkc->channel->name));
 207         }
 208         lkc->channel->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 209
 210         lkc->fd = -1;
 211         lkc->stream_count = 0;
 212         lkc->event_count = 0;
 213         lkc->enabled = 1;
 214         /* Init linked list */
 215         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 216         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 217         CDS_INIT_LIST_HEAD(&lkc->ctx_list);
 218
 219         return lkc;
 220
 221 error:
 222         return NULL;
 223 }
 224
 225 /*
 226  * Allocate and init a kernel context object.
 227  *
 228  * Return the allocated object or NULL on error.
 229  */
 230 struct ltt_kernel_context *trace_kernel_create_context(
 231                 struct lttng_kernel_context *ctx)
 232 {
 233         struct ltt_kernel_context *kctx;
 234
 235         kctx = zmalloc(sizeof(*kctx));
 236         if (!kctx) {
 237                 PERROR("zmalloc kernel context");
 238                 goto error;
 239         }
 240
 241         if (ctx) {
 242                 memcpy(&kctx->ctx, ctx, sizeof(kctx->ctx));
 243         }
 244
 245         CDS_INIT_LIST_HEAD(&kctx->list);
 246
 247 error:
 248         return kctx;
 249 }
 250
 251 /*
 252  * Allocate and initialize a kernel event. Set name and event type.
 253  * We own filter_expression, and filter.
 254  *
 255  * Return pointer to structure or NULL.
 256  */
 257 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev,
 258                 char *filter_expression, struct lttng_filter_bytecode *filter)
 259 {
 260         struct ltt_kernel_event *lke;
 261         struct lttng_kernel_event *attr;
 262
 263         assert(ev);
 264
 265         lke = zmalloc(sizeof(struct ltt_kernel_event));
 266         attr = zmalloc(sizeof(struct lttng_kernel_event));
 267         if (lke == NULL || attr == NULL) {
 268                 PERROR("kernel event zmalloc");
 269                 goto error;
 270         }
 271
 272         switch (ev->type) {
 273         case LTTNG_EVENT_PROBE:
 274                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 275                 attr->u.kprobe.addr = ev->attr.probe.addr;
 276                 attr->u.kprobe.offset = ev->attr.probe.offset;
 277                 strncpy(attr->u.kprobe.symbol_name,
 278                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 279                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 280                 break;
 281         case LTTNG_EVENT_FUNCTION:
 282                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 283                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 284                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 285                 strncpy(attr->u.kretprobe.symbol_name,
 286                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 287                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 288                 break;
 289         case LTTNG_EVENT_FUNCTION_ENTRY:
 290                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 291                 strncpy(attr->u.ftrace.symbol_name,
 292                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 293                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 294                 break;
 295         case LTTNG_EVENT_TRACEPOINT:
 296                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 297                 break;
 298         case LTTNG_EVENT_SYSCALL:
 299                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 300                 break;
 301         case LTTNG_EVENT_ALL:
 302                 attr->instrumentation = LTTNG_KERNEL_ALL;
 303                 break;
 304         default:
 305                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 306                 goto error;
 307         }
 308
 309         /* Copy event name */
 310         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 311         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 312
 313         /* Setting up a kernel event */
 314         lke->fd = -1;
 315         lke->event = attr;
 316         lke->enabled = 1;
 317         lke->filter_expression = filter_expression;
 318         lke->filter = filter;
 319
 320         return lke;
 321
 322 error:
 323         free(filter_expression);
 324         free(filter);
 325         free(lke);
 326         free(attr);
 327         return NULL;
 328 }
 329
 330 /*
 331  * Allocate and initialize a kernel metadata.
 332  *
 333  * Return pointer to structure or NULL.
 334  */
 335 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 336 {
 337         struct ltt_kernel_metadata *lkm;
 338         struct lttng_channel *chan;
 339
 340         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 341         chan = zmalloc(sizeof(struct lttng_channel));
 342         if (lkm == NULL || chan == NULL) {
 343                 PERROR("kernel metadata zmalloc");
 344                 goto error;
 345         }
 346
 347         /* Set default attributes */
 348         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 349         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 350         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 351         chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
 352         chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
 353         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 354
 355         /* Init metadata */
 356         lkm->fd = -1;
 357         lkm->conf = chan;
 358
 359         return lkm;
 360
 361 error:
 362         free(lkm);
 363         free(chan);
 364         return NULL;
 365 }
 366
 367 /*
 368  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 369  * default.
 370  *
 371  * Return pointer to structure or NULL.
 372  */
 373 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 374                 unsigned int count)
 375 {
 376         int ret;
 377         struct ltt_kernel_stream *lks;
 378
 379         assert(name);
 380
 381         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 382         if (lks == NULL) {
 383                 PERROR("kernel stream zmalloc");
 384                 goto error;
 385         }
 386
 387         /* Set name */
 388         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 389         if (ret < 0) {
 390                 PERROR("snprintf stream name");
 391                 goto error;
 392         }
 393         lks->name[sizeof(lks->name) - 1] = '\0';
 394
 395         /* Init stream */
 396         lks->fd = -1;
 397         lks->state = 0;
 398         lks->cpu = count;
 399
 400         return lks;
 401
 402 error:
 403         return NULL;
 404 }
 405
 406 /*
 407  * Cleanup kernel stream structure.
 408  */
 409 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 410 {
 411         assert(stream);
 412
 413         DBG("[trace] Closing stream fd %d", stream->fd);
 414         /* Close kernel fd */
 415         if (stream->fd >= 0) {
 416                 int ret;
 417
 418                 ret = close(stream->fd);
 419                 if (ret) {
 420                         PERROR("close");
 421                 }
 422         }
 423         /* Remove from stream list */
 424         cds_list_del(&stream->list);
 425
 426         free(stream);
 427 }
 428
 429 /*
 430  * Cleanup kernel event structure.
 431  */
 432 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 433 {
 434         assert(event);
 435
 436         if (event->fd >= 0) {
 437                 int ret;
 438
 439                 DBG("[trace] Closing event fd %d", event->fd);
 440                 /* Close kernel fd */
 441                 ret = close(event->fd);
 442                 if (ret) {
 443                         PERROR("close");
 444                 }
 445         } else {
 446                 DBG("[trace] Tearing down event (no associated fd)");
 447         }
 448
 449         /* Remove from event list */
 450         cds_list_del(&event->list);
 451
 452         free(event->filter_expression);
 453         free(event->filter);
 454
 455         free(event->event);
 456         free(event);
 457 }
 458
 459 /*
 460  * Cleanup kernel context structure.
 461  */
 462 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 463 {
 464         assert(ctx);
 465
 466         cds_list_del(&ctx->list);
 467         free(ctx);
 468 }
 469
 470 /*
 471  * Cleanup kernel channel structure.
 472  */
 473 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 474 {
 475         struct ltt_kernel_stream *stream, *stmp;
 476         struct ltt_kernel_event *event, *etmp;
 477         struct ltt_kernel_context *ctx, *ctmp;
 478         int ret;
 479
 480         assert(channel);
 481
 482         DBG("[trace] Closing channel fd %d", channel->fd);
 483         /* Close kernel fd */
 484         if (channel->fd >= 0) {
 485                 ret = close(channel->fd);
 486                 if (ret) {
 487                         PERROR("close");
 488                 }
 489         }
 490
 491         /* For each stream in the channel list */
 492         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 493                 trace_kernel_destroy_stream(stream);
 494         }
 495
 496         /* For each event in the channel list */
 497         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 498                 trace_kernel_destroy_event(event);
 499         }
 500
 501         /* For each context in the channel list */
 502         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 503                 trace_kernel_destroy_context(ctx);
 504         }
 505
 506         /* Remove from channel list */
 507         cds_list_del(&channel->list);
 508
 509         free(channel->channel);
 510         free(channel);
 511 }
 512
 513 /*
 514  * Cleanup kernel metadata structure.
 515  */
 516 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 517 {
 518         assert(metadata);
 519
 520         DBG("[trace] Closing metadata fd %d", metadata->fd);
 521         /* Close kernel fd */
 522         if (metadata->fd >= 0) {
 523                 int ret;
 524
 525                 ret = close(metadata->fd);
 526                 if (ret) {
 527                         PERROR("close");
 528                 }
 529         }
 530
 531         free(metadata->conf);
 532         free(metadata);
 533 }
 534
 535 /*
 536  * Cleanup kernel session structure
 537  *
 538  * Should *NOT* be called with RCU read-side lock held.
 539  */
 540 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 541 {
 542         struct ltt_kernel_channel *channel, *ctmp;
 543         int ret;
 544
 545         assert(session);
 546
 547         DBG("[trace] Closing session fd %d", session->fd);
 548         /* Close kernel fds */
 549         if (session->fd >= 0) {
 550                 ret = close(session->fd);
 551                 if (ret) {
 552                         PERROR("close");
 553                 }
 554         }
 555
 556         if (session->metadata_stream_fd >= 0) {
 557                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 558                 ret = close(session->metadata_stream_fd);
 559                 if (ret) {
 560                         PERROR("close");
 561                 }
 562         }
 563
 564         if (session->metadata != NULL) {
 565                 trace_kernel_destroy_metadata(session->metadata);
 566         }
 567
 568         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 569                 trace_kernel_destroy_channel(channel);
 570         }
 571
 572         /* Wipe consumer output object */
 573         consumer_output_put(session->consumer);
 574
 575         free(session);
 576 }