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