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