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