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