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         if (session == NULL) {
  39                 ERR("Undefine session");
  40                 goto error;
  41         }
  42
  43         DBG("Trying to find channel %s", name);
  44
  45         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  46                 if (strcmp(name, chan->channel->name) == 0) {
  47                         DBG("Found channel by name %s", name);
  48                         return chan;
  49                 }
  50         }
  51
  52 error:
  53         return NULL;
  54 }
  55
  56 /*
  57  * Find the event name for the given channel.
  58  */
  59 struct ltt_kernel_event *trace_kernel_get_event_by_name(
  60                 char *name, struct ltt_kernel_channel *channel)
  61 {
  62         struct ltt_kernel_event *ev;
  63
  64         if (channel == NULL) {
  65                 ERR("Undefine channel");
  66                 goto error;
  67         }
  68
  69         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  70                 if (strcmp(name, ev->event->name) == 0) {
  71                         DBG("Found event by name %s for channel %s", name,
  72                                         channel->channel->name);
  73                         return ev;
  74                 }
  75         }
  76
  77 error:
  78         return NULL;
  79 }
  80
  81 /*
  82  * Allocate and initialize a kernel session data structure.
  83  *
  84  * Return pointer to structure or NULL.
  85  */
  86 struct ltt_kernel_session *trace_kernel_create_session(char *path)
  87 {
  88         int ret;
  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         if (path && strlen(path) > 0) {
 120                 /* Use the default consumer output which is the tracing session path. */
 121                 ret = snprintf(lks->consumer->dst.trace_path, PATH_MAX,
 122                                 "%s" DEFAULT_KERNEL_TRACE_DIR, path);
 123                 if (ret < 0) {
 124                         PERROR("snprintf consumer trace path");
 125                         goto error;
 126                 }
 127
 128                 /* Set session path */
 129                 ret = asprintf(&lks->trace_path, "%s" DEFAULT_KERNEL_TRACE_DIR, path);
 130                 if (ret < 0) {
 131                         PERROR("asprintf kernel traces path");
 132                         goto error;
 133                 }
 134         }
 135
 136         return lks;
 137
 138 error:
 139         free(lks);
 140
 141 alloc_error:
 142         return NULL;
 143 }
 144
 145 /*
 146  * Allocate and initialize a kernel channel data structure.
 147  *
 148  * Return pointer to structure or NULL.
 149  */
 150 struct ltt_kernel_channel *trace_kernel_create_channel(
 151                 struct lttng_channel *chan, char *path)
 152 {
 153         struct ltt_kernel_channel *lkc;
 154
 155         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 156         if (lkc == NULL) {
 157                 PERROR("ltt_kernel_channel zmalloc");
 158                 goto error;
 159         }
 160
 161         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 162         if (lkc->channel == NULL) {
 163                 PERROR("lttng_channel zmalloc");
 164                 goto error;
 165         }
 166         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 167
 168         lkc->fd = -1;
 169         lkc->stream_count = 0;
 170         lkc->event_count = 0;
 171         lkc->enabled = 1;
 172         lkc->ctx = NULL;
 173         /* Init linked list */
 174         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 175         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 176
 177         return lkc;
 178
 179 error:
 180         return NULL;
 181 }
 182
 183 /*
 184  * Allocate and initialize a kernel event. Set name and event type.
 185  *
 186  * Return pointer to structure or NULL.
 187  */
 188 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 189 {
 190         struct ltt_kernel_event *lke;
 191         struct lttng_kernel_event *attr;
 192
 193         lke = zmalloc(sizeof(struct ltt_kernel_event));
 194         attr = zmalloc(sizeof(struct lttng_kernel_event));
 195         if (lke == NULL || attr == NULL) {
 196                 PERROR("kernel event zmalloc");
 197                 goto error;
 198         }
 199
 200         switch (ev->type) {
 201         case LTTNG_EVENT_PROBE:
 202                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 203                 attr->u.kprobe.addr = ev->attr.probe.addr;
 204                 attr->u.kprobe.offset = ev->attr.probe.offset;
 205                 strncpy(attr->u.kprobe.symbol_name,
 206                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 207                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 208                 break;
 209         case LTTNG_EVENT_FUNCTION:
 210                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 211                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 212                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 213                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 214                 strncpy(attr->u.kretprobe.symbol_name,
 215                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 216                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 217                 break;
 218         case LTTNG_EVENT_FUNCTION_ENTRY:
 219                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 220                 strncpy(attr->u.ftrace.symbol_name,
 221                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 222                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 223                 break;
 224         case LTTNG_EVENT_TRACEPOINT:
 225                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 226                 break;
 227         case LTTNG_EVENT_SYSCALL:
 228                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 229                 break;
 230         case LTTNG_EVENT_ALL:
 231                 attr->instrumentation = LTTNG_KERNEL_ALL;
 232                 break;
 233         default:
 234                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 235                 goto error;
 236         }
 237
 238         /* Copy event name */
 239         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 240         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 241
 242         /* Setting up a kernel event */
 243         lke->fd = -1;
 244         lke->event = attr;
 245         lke->enabled = 1;
 246
 247         return lke;
 248
 249 error:
 250         free(lke);
 251         free(attr);
 252         return NULL;
 253 }
 254
 255 /*
 256  * Allocate and initialize a kernel metadata.
 257  *
 258  * Return pointer to structure or NULL.
 259  */
 260 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 261 {
 262         struct ltt_kernel_metadata *lkm;
 263         struct lttng_channel *chan;
 264
 265         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 266         chan = zmalloc(sizeof(struct lttng_channel));
 267         if (lkm == NULL || chan == NULL) {
 268                 PERROR("kernel metadata zmalloc");
 269                 goto error;
 270         }
 271
 272         /* Set default attributes */
 273         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 274         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 275         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 276         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 277         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 278         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 279
 280         /* Init metadata */
 281         lkm->fd = -1;
 282         lkm->conf = chan;
 283
 284         return lkm;
 285
 286 error:
 287         free(lkm);
 288         free(chan);
 289         return NULL;
 290 }
 291
 292 /*
 293  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 294  * default.
 295  *
 296  * Return pointer to structure or NULL.
 297  */
 298 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 299                 unsigned int count)
 300 {
 301         int ret;
 302         struct ltt_kernel_stream *lks;
 303
 304         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 305         if (lks == NULL) {
 306                 PERROR("kernel stream zmalloc");
 307                 goto error;
 308         }
 309
 310         /* Set name */
 311         ret = snprintf(lks->name, sizeof(lks->name), "%s_%d", name, count);
 312         if (ret < 0) {
 313                 PERROR("snprintf stream name");
 314                 goto error;
 315         }
 316         lks->name[sizeof(lks->name) - 1] = '\0';
 317
 318         /* Init stream */
 319         lks->fd = -1;
 320         lks->state = 0;
 321
 322         return lks;
 323
 324 error:
 325         return NULL;
 326 }
 327
 328 /*
 329  * Cleanup kernel stream structure.
 330  */
 331 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 332 {
 333         int ret;
 334
 335         DBG("[trace] Closing stream fd %d", stream->fd);
 336         /* Close kernel fd */
 337         if (stream->fd >= 0) {
 338                 ret = close(stream->fd);
 339                 if (ret) {
 340                         PERROR("close");
 341                 }
 342         }
 343         /* Remove from stream list */
 344         cds_list_del(&stream->list);
 345
 346         free(stream);
 347 }
 348
 349 /*
 350  * Cleanup kernel event structure.
 351  */
 352 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 353 {
 354         int ret;
 355
 356         if (event->fd >= 0) {
 357                 DBG("[trace] Closing event fd %d", event->fd);
 358                 /* Close kernel fd */
 359                 ret = close(event->fd);
 360                 if (ret) {
 361                         PERROR("close");
 362                 }
 363         } else {
 364                 DBG("[trace] Tearing down event (no associated fd)");
 365         }
 366
 367         /* Remove from event list */
 368         cds_list_del(&event->list);
 369
 370         free(event->event);
 371         free(event);
 372 }
 373
 374 /*
 375  * Cleanup kernel channel structure.
 376  */
 377 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 378 {
 379         struct ltt_kernel_stream *stream, *stmp;
 380         struct ltt_kernel_event *event, *etmp;
 381         int ret;
 382
 383         DBG("[trace] Closing channel fd %d", channel->fd);
 384         /* Close kernel fd */
 385         if (channel->fd >= 0) {
 386                 ret = close(channel->fd);
 387                 if (ret) {
 388                         PERROR("close");
 389                 }
 390         }
 391
 392         /* For each stream in the channel list */
 393         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 394                 trace_kernel_destroy_stream(stream);
 395         }
 396
 397         /* For each event in the channel list */
 398         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 399                 trace_kernel_destroy_event(event);
 400         }
 401
 402         /* Remove from channel list */
 403         cds_list_del(&channel->list);
 404
 405         free(channel->channel);
 406         free(channel->ctx);
 407         free(channel);
 408 }
 409
 410 /*
 411  * Cleanup kernel metadata structure.
 412  */
 413 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 414 {
 415         int ret;
 416
 417         DBG("[trace] Closing metadata fd %d", metadata->fd);
 418         /* Close kernel fd */
 419         if (metadata->fd >= 0) {
 420                 ret = close(metadata->fd);
 421                 if (ret) {
 422                         PERROR("close");
 423                 }
 424         }
 425
 426         free(metadata->conf);
 427         free(metadata);
 428 }
 429
 430 /*
 431  * Cleanup kernel session structure
 432  */
 433 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 434 {
 435         struct ltt_kernel_channel *channel, *ctmp;
 436         int ret;
 437
 438         DBG("[trace] Closing session fd %d", session->fd);
 439         /* Close kernel fds */
 440         if (session->fd >= 0) {
 441                 ret = close(session->fd);
 442                 if (ret) {
 443                         PERROR("close");
 444                 }
 445         }
 446
 447         if (session->metadata_stream_fd >= 0) {
 448                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 449                 ret = close(session->metadata_stream_fd);
 450                 if (ret) {
 451                         PERROR("close");
 452                 }
 453         }
 454
 455         if (session->metadata != NULL) {
 456                 trace_kernel_destroy_metadata(session->metadata);
 457         }
 458
 459         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 460                 trace_kernel_destroy_channel(channel);
 461         }
 462
 463         /* Wipe consumer output object */
 464         consumer_destroy_output(session->consumer);
 465         consumer_destroy_output(session->tmp_consumer);
 466
 467         free(session->trace_path);
 468         free(session);
 469 }