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