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