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  *
 262  * Return pointer to structure or NULL.
 263  */
 264 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev,
 265                 char *filter_expression, struct lttng_filter_bytecode *filter)
 266 {
 267         struct ltt_kernel_event *lke;
 268         struct lttng_kernel_event *attr;
 269
 270         assert(ev);
 271
 272         lke = zmalloc(sizeof(struct ltt_kernel_event));
 273         attr = zmalloc(sizeof(struct lttng_kernel_event));
 274         if (lke == NULL || attr == NULL) {
 275                 PERROR("kernel event zmalloc");
 276                 goto error;
 277         }
 278
 279         switch (ev->type) {
 280         case LTTNG_EVENT_PROBE:
 281                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 282                 attr->u.kprobe.addr = ev->attr.probe.addr;
 283                 attr->u.kprobe.offset = ev->attr.probe.offset;
 284                 strncpy(attr->u.kprobe.symbol_name,
 285                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 286                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 287                 break;
 288         case LTTNG_EVENT_FUNCTION:
 289                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 290                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 291                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 292                 strncpy(attr->u.kretprobe.symbol_name,
 293                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 294                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 295                 break;
 296         case LTTNG_EVENT_FUNCTION_ENTRY:
 297                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 298                 strncpy(attr->u.ftrace.symbol_name,
 299                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 300                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 301                 break;
 302         case LTTNG_EVENT_TRACEPOINT:
 303                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 304                 break;
 305         case LTTNG_EVENT_SYSCALL:
 306                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 307                 break;
 308         case LTTNG_EVENT_ALL:
 309                 attr->instrumentation = LTTNG_KERNEL_ALL;
 310                 break;
 311         default:
 312                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 313                 goto error;
 314         }
 315
 316         /* Copy event name */
 317         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 318         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 319
 320         /* Setting up a kernel event */
 321         lke->fd = -1;
 322         lke->event = attr;
 323         lke->enabled = 1;
 324         lke->filter_expression = filter_expression;
 325         lke->filter = filter;
 326
 327         return lke;
 328
 329 error:
 330         free(lke);
 331         free(attr);
 332         return NULL;
 333 }
 334
 335 /*
 336  * Allocate and initialize a kernel metadata.
 337  *
 338  * Return pointer to structure or NULL.
 339  */
 340 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 341 {
 342         struct ltt_kernel_metadata *lkm;
 343         struct lttng_channel *chan;
 344
 345         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 346         chan = zmalloc(sizeof(struct lttng_channel));
 347         if (lkm == NULL || chan == NULL) {
 348                 PERROR("kernel metadata zmalloc");
 349                 goto error;
 350         }
 351
 352         /* Set default attributes */
 353         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 354         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 355         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 356         chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
 357         chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
 358         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 359
 360         /* Init metadata */
 361         lkm->fd = -1;
 362         lkm->conf = chan;
 363
 364         return lkm;
 365
 366 error:
 367         free(lkm);
 368         free(chan);
 369         return NULL;
 370 }
 371
 372 /*
 373  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 374  * default.
 375  *
 376  * Return pointer to structure or NULL.
 377  */
 378 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 379                 unsigned int count)
 380 {
 381         int ret;
 382         struct ltt_kernel_stream *lks;
 383
 384         assert(name);
 385
 386         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 387         if (lks == NULL) {
 388                 PERROR("kernel stream zmalloc");
 389                 goto error;
 390         }
 391
 392         /* Set name */
 393         ret = snprintf(lks->name, sizeof(lks->name), "%s_%u", name, count);
 394         if (ret < 0) {
 395                 PERROR("snprintf stream name");
 396                 goto error;
 397         }
 398         lks->name[sizeof(lks->name) - 1] = '\0';
 399
 400         /* Init stream */
 401         lks->fd = -1;
 402         lks->state = 0;
 403         lks->cpu = count;
 404
 405         return lks;
 406
 407 error:
 408         return NULL;
 409 }
 410
 411 /*
 412  * Cleanup kernel stream structure.
 413  */
 414 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 415 {
 416         assert(stream);
 417
 418         DBG("[trace] Closing stream fd %d", stream->fd);
 419         /* Close kernel fd */
 420         if (stream->fd >= 0) {
 421                 int ret;
 422
 423                 ret = close(stream->fd);
 424                 if (ret) {
 425                         PERROR("close");
 426                 }
 427         }
 428         /* Remove from stream list */
 429         cds_list_del(&stream->list);
 430
 431         free(stream);
 432 }
 433
 434 /*
 435  * Cleanup kernel event structure.
 436  */
 437 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 438 {
 439         assert(event);
 440
 441         if (event->fd >= 0) {
 442                 int ret;
 443
 444                 DBG("[trace] Closing event fd %d", event->fd);
 445                 /* Close kernel fd */
 446                 ret = close(event->fd);
 447                 if (ret) {
 448                         PERROR("close");
 449                 }
 450         } else {
 451                 DBG("[trace] Tearing down event (no associated fd)");
 452         }
 453
 454         /* Remove from event list */
 455         cds_list_del(&event->list);
 456
 457         free(event->filter_expression);
 458         free(event->filter);
 459
 460         free(event->event);
 461         free(event);
 462 }
 463
 464 /*
 465  * Cleanup kernel context structure.
 466  */
 467 void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 468 {
 469         assert(ctx);
 470
 471         cds_list_del(&ctx->list);
 472         free(ctx);
 473 }
 474
 475 /*
 476  * Cleanup kernel channel structure.
 477  */
 478 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 479 {
 480         struct ltt_kernel_stream *stream, *stmp;
 481         struct ltt_kernel_event *event, *etmp;
 482         struct ltt_kernel_context *ctx, *ctmp;
 483         int ret;
 484
 485         assert(channel);
 486
 487         DBG("[trace] Closing channel fd %d", channel->fd);
 488         /* Close kernel fd */
 489         if (channel->fd >= 0) {
 490                 ret = close(channel->fd);
 491                 if (ret) {
 492                         PERROR("close");
 493                 }
 494         }
 495
 496         /* For each stream in the channel list */
 497         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 498                 trace_kernel_destroy_stream(stream);
 499         }
 500
 501         /* For each event in the channel list */
 502         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 503                 trace_kernel_destroy_event(event);
 504         }
 505
 506         /* For each context in the channel list */
 507         cds_list_for_each_entry_safe(ctx, ctmp, &channel->ctx_list, list) {
 508                 trace_kernel_destroy_context(ctx);
 509         }
 510
 511         /* Remove from channel list */
 512         cds_list_del(&channel->list);
 513
 514         free(channel->channel);
 515         free(channel);
 516 }
 517
 518 /*
 519  * Cleanup kernel metadata structure.
 520  */
 521 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 522 {
 523         assert(metadata);
 524
 525         DBG("[trace] Closing metadata fd %d", metadata->fd);
 526         /* Close kernel fd */
 527         if (metadata->fd >= 0) {
 528                 int ret;
 529
 530                 ret = close(metadata->fd);
 531                 if (ret) {
 532                         PERROR("close");
 533                 }
 534         }
 535
 536         free(metadata->conf);
 537         free(metadata);
 538 }
 539
 540 /*
 541  * Cleanup kernel session structure
 542  *
 543  * Should *NOT* be called with RCU read-side lock held.
 544  */
 545 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 546 {
 547         struct ltt_kernel_channel *channel, *ctmp;
 548         int ret;
 549
 550         assert(session);
 551
 552         DBG("[trace] Closing session fd %d", session->fd);
 553         /* Close kernel fds */
 554         if (session->fd >= 0) {
 555                 ret = close(session->fd);
 556                 if (ret) {
 557                         PERROR("close");
 558                 }
 559         }
 560
 561         if (session->metadata_stream_fd >= 0) {
 562                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 563                 ret = close(session->metadata_stream_fd);
 564                 if (ret) {
 565                         PERROR("close");
 566                 }
 567         }
 568
 569         if (session->metadata != NULL) {
 570                 trace_kernel_destroy_metadata(session->metadata);
 571         }
 572
 573         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 574                 trace_kernel_destroy_channel(channel);
 575         }
 576
 577         /* Wipe consumer output object */
 578         consumer_destroy_output(session->consumer);
 579         consumer_destroy_output(session->tmp_consumer);
 580
 581         free(session);
 582 }