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         DBG("Trying to find channel %s", name);
  42
  43         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  44                 if (strcmp(name, chan->channel->name) == 0) {
  45                         DBG("Found channel by name %s", name);
  46                         return chan;
  47                 }
  48         }
  49
  50         return NULL;
  51 }
  52
  53 /*
  54  * Find the event name for the given channel.
  55  */
  56 struct ltt_kernel_event *trace_kernel_get_event_by_name(
  57                 char *name, struct ltt_kernel_channel *channel)
  58 {
  59         struct ltt_kernel_event *ev;
  60
  61         assert(name);
  62         assert(channel);
  63
  64         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  65                 if (strcmp(name, ev->event->name) == 0) {
  66                         DBG("Found event by name %s for channel %s", name,
  67                                         channel->channel->name);
  68                         return ev;
  69                 }
  70         }
  71
  72         return NULL;
  73 }
  74
  75 /*
  76  * Allocate and initialize a kernel session data structure.
  77  *
  78  * Return pointer to structure or NULL.
  79  */
  80 struct ltt_kernel_session *trace_kernel_create_session(char *path)
  81 {
  82         struct ltt_kernel_session *lks = NULL;
  83
  84         /* Allocate a new ltt kernel session */
  85         lks = zmalloc(sizeof(struct ltt_kernel_session));
  86         if (lks == NULL) {
  87                 PERROR("create kernel session zmalloc");
  88                 goto alloc_error;
  89         }
  90
  91         /* Init data structure */
  92         lks->fd = -1;
  93         lks->metadata_stream_fd = -1;
  94         lks->channel_count = 0;
  95         lks->stream_count_global = 0;
  96         lks->metadata = NULL;
  97         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
  98
  99         lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 100         if (lks->consumer == NULL) {
 101                 goto error;
 102         }
 103
 104         /*
 105          * The tmp_consumer stays NULL until a set_consumer_uri command is
 106          * executed. At this point, the consumer should be nullify until an
 107          * enable_consumer command. This assignment is symbolic since we've zmalloc
 108          * the struct.
 109          */
 110         lks->tmp_consumer = NULL;
 111
 112         if (path && strlen(path) > 0) {
 113                 int ret;
 114
 115                 /* Use the default consumer output which is the tracing session path. */
 116                 ret = snprintf(lks->consumer->dst.trace_path, PATH_MAX,
 117                                 "%s" DEFAULT_KERNEL_TRACE_DIR, path);
 118                 if (ret < 0) {
 119                         PERROR("snprintf consumer trace path");
 120                         goto error;
 121                 }
 122
 123                 /* Set session path */
 124                 ret = asprintf(&lks->trace_path, "%s" DEFAULT_KERNEL_TRACE_DIR, path);
 125                 if (ret < 0) {
 126                         PERROR("asprintf kernel traces path");
 127                         goto error;
 128                 }
 129         }
 130
 131         return lks;
 132
 133 error:
 134         free(lks);
 135
 136 alloc_error:
 137         return NULL;
 138 }
 139
 140 /*
 141  * Allocate and initialize a kernel channel data structure.
 142  *
 143  * Return pointer to structure or NULL.
 144  */
 145 struct ltt_kernel_channel *trace_kernel_create_channel(
 146                 struct lttng_channel *chan)
 147 {
 148         struct ltt_kernel_channel *lkc;
 149
 150         assert(chan);
 151
 152         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 153         if (lkc == NULL) {
 154                 PERROR("ltt_kernel_channel zmalloc");
 155                 goto error;
 156         }
 157
 158         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 159         if (lkc->channel == NULL) {
 160                 PERROR("lttng_channel zmalloc");
 161                 goto error;
 162         }
 163         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 164
 165         lkc->fd = -1;
 166         lkc->stream_count = 0;
 167         lkc->event_count = 0;
 168         lkc->enabled = 1;
 169         lkc->ctx = NULL;
 170         /* Init linked list */
 171         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 172         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 173
 174         return lkc;
 175
 176 error:
 177         return NULL;
 178 }
 179
 180 /*
 181  * Allocate and initialize a kernel event. Set name and event type.
 182  *
 183  * Return pointer to structure or NULL.
 184  */
 185 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 186 {
 187         struct ltt_kernel_event *lke;
 188         struct lttng_kernel_event *attr;
 189
 190         assert(ev);
 191
 192         lke = zmalloc(sizeof(struct ltt_kernel_event));
 193         attr = zmalloc(sizeof(struct lttng_kernel_event));
 194         if (lke == NULL || attr == NULL) {
 195                 PERROR("kernel event zmalloc");
 196                 goto error;
 197         }
 198
 199         switch (ev->type) {
 200         case LTTNG_EVENT_PROBE:
 201                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 202                 attr->u.kprobe.addr = ev->attr.probe.addr;
 203                 attr->u.kprobe.offset = ev->attr.probe.offset;
 204                 strncpy(attr->u.kprobe.symbol_name,
 205                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 206                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 207                 break;
 208         case LTTNG_EVENT_FUNCTION:
 209                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 210                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 211                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 212                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 213                 strncpy(attr->u.kretprobe.symbol_name,
 214                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 215                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 216                 break;
 217         case LTTNG_EVENT_FUNCTION_ENTRY:
 218                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 219                 strncpy(attr->u.ftrace.symbol_name,
 220                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 221                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 222                 break;
 223         case LTTNG_EVENT_TRACEPOINT:
 224                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 225                 break;
 226         case LTTNG_EVENT_SYSCALL:
 227                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 228                 break;
 229         case LTTNG_EVENT_ALL:
 230                 attr->instrumentation = LTTNG_KERNEL_ALL;
 231                 break;
 232         default:
 233                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 234                 goto error;
 235         }
 236
 237         /* Copy event name */
 238         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 239         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 240
 241         /* Setting up a kernel event */
 242         lke->fd = -1;
 243         lke->event = attr;
 244         lke->enabled = 1;
 245
 246         return lke;
 247
 248 error:
 249         free(lke);
 250         free(attr);
 251         return NULL;
 252 }
 253
 254 /*
 255  * Allocate and initialize a kernel metadata.
 256  *
 257  * Return pointer to structure or NULL.
 258  */
 259 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 260 {
 261         struct ltt_kernel_metadata *lkm;
 262         struct lttng_channel *chan;
 263
 264         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 265         chan = zmalloc(sizeof(struct lttng_channel));
 266         if (lkm == NULL || chan == NULL) {
 267                 PERROR("kernel metadata zmalloc");
 268                 goto error;
 269         }
 270
 271         /* Set default attributes */
 272         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 273         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 274         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 275         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 276         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 277         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 278
 279         /* Init metadata */
 280         lkm->fd = -1;
 281         lkm->conf = chan;
 282
 283         return lkm;
 284
 285 error:
 286         free(lkm);
 287         free(chan);
 288         return NULL;
 289 }
 290
 291 /*
 292  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 293  * default.
 294  *
 295  * Return pointer to structure or NULL.
 296  */
 297 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 298                 unsigned int count)
 299 {
 300         int ret;
 301         struct ltt_kernel_stream *lks;
 302
 303         assert(name);
 304
 305         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 306         if (lks == NULL) {
 307                 PERROR("kernel stream zmalloc");
 308                 goto error;
 309         }
 310
 311         /* Set name */
 312         ret = snprintf(lks->name, sizeof(lks->name), "%s_%d", name, count);
 313         if (ret < 0) {
 314                 PERROR("snprintf stream name");
 315                 goto error;
 316         }
 317         lks->name[sizeof(lks->name) - 1] = '\0';
 318
 319         /* Init stream */
 320         lks->fd = -1;
 321         lks->state = 0;
 322
 323         return lks;
 324
 325 error:
 326         return NULL;
 327 }
 328
 329 /*
 330  * Cleanup kernel stream structure.
 331  */
 332 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 333 {
 334         assert(stream);
 335
 336         DBG("[trace] Closing stream fd %d", stream->fd);
 337         /* Close kernel fd */
 338         if (stream->fd >= 0) {
 339                 int ret;
 340
 341                 ret = close(stream->fd);
 342                 if (ret) {
 343                         PERROR("close");
 344                 }
 345         }
 346         /* Remove from stream list */
 347         cds_list_del(&stream->list);
 348
 349         free(stream);
 350 }
 351
 352 /*
 353  * Cleanup kernel event structure.
 354  */
 355 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 356 {
 357         assert(event);
 358
 359         if (event->fd >= 0) {
 360                 int ret;
 361
 362                 DBG("[trace] Closing event fd %d", event->fd);
 363                 /* Close kernel fd */
 364                 ret = close(event->fd);
 365                 if (ret) {
 366                         PERROR("close");
 367                 }
 368         } else {
 369                 DBG("[trace] Tearing down event (no associated fd)");
 370         }
 371
 372         /* Remove from event list */
 373         cds_list_del(&event->list);
 374
 375         free(event->event);
 376         free(event);
 377 }
 378
 379 /*
 380  * Cleanup kernel channel structure.
 381  */
 382 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 383 {
 384         struct ltt_kernel_stream *stream, *stmp;
 385         struct ltt_kernel_event *event, *etmp;
 386         int ret;
 387
 388         assert(channel);
 389
 390         DBG("[trace] Closing channel fd %d", channel->fd);
 391         /* Close kernel fd */
 392         if (channel->fd >= 0) {
 393                 ret = close(channel->fd);
 394                 if (ret) {
 395                         PERROR("close");
 396                 }
 397         }
 398
 399         /* For each stream in the channel list */
 400         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 401                 trace_kernel_destroy_stream(stream);
 402         }
 403
 404         /* For each event in the channel list */
 405         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 406                 trace_kernel_destroy_event(event);
 407         }
 408
 409         /* Remove from channel list */
 410         cds_list_del(&channel->list);
 411
 412         free(channel->channel);
 413         free(channel->ctx);
 414         free(channel);
 415 }
 416
 417 /*
 418  * Cleanup kernel metadata structure.
 419  */
 420 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 421 {
 422         assert(metadata);
 423
 424         DBG("[trace] Closing metadata fd %d", metadata->fd);
 425         /* Close kernel fd */
 426         if (metadata->fd >= 0) {
 427                 int ret;
 428
 429                 ret = close(metadata->fd);
 430                 if (ret) {
 431                         PERROR("close");
 432                 }
 433         }
 434
 435         free(metadata->conf);
 436         free(metadata);
 437 }
 438
 439 /*
 440  * Cleanup kernel session structure
 441  */
 442 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 443 {
 444         struct ltt_kernel_channel *channel, *ctmp;
 445         int ret;
 446
 447         assert(session);
 448
 449         DBG("[trace] Closing session fd %d", session->fd);
 450         /* Close kernel fds */
 451         if (session->fd >= 0) {
 452                 ret = close(session->fd);
 453                 if (ret) {
 454                         PERROR("close");
 455                 }
 456         }
 457
 458         if (session->metadata_stream_fd >= 0) {
 459                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 460                 ret = close(session->metadata_stream_fd);
 461                 if (ret) {
 462                         PERROR("close");
 463                 }
 464         }
 465
 466         if (session->metadata != NULL) {
 467                 trace_kernel_destroy_metadata(session->metadata);
 468         }
 469
 470         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 471                 trace_kernel_destroy_channel(channel);
 472         }
 473
 474         /* Wipe consumer output object */
 475         consumer_destroy_output(session->consumer);
 476         consumer_destroy_output(session->tmp_consumer);
 477
 478         free(session->trace_path);
 479         free(session);
 480 }