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         lkc->ctx = NULL;
 169         /* Init linked list */
 170         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 171         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 172
 173         return lkc;
 174
 175 error:
 176         return NULL;
 177 }
 178
 179 /*
 180  * Allocate and initialize a kernel event. Set name and event type.
 181  *
 182  * Return pointer to structure or NULL.
 183  */
 184 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 185 {
 186         struct ltt_kernel_event *lke;
 187         struct lttng_kernel_event *attr;
 188
 189         assert(ev);
 190
 191         lke = zmalloc(sizeof(struct ltt_kernel_event));
 192         attr = zmalloc(sizeof(struct lttng_kernel_event));
 193         if (lke == NULL || attr == NULL) {
 194                 PERROR("kernel event zmalloc");
 195                 goto error;
 196         }
 197
 198         switch (ev->type) {
 199         case LTTNG_EVENT_PROBE:
 200                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 201                 attr->u.kprobe.addr = ev->attr.probe.addr;
 202                 attr->u.kprobe.offset = ev->attr.probe.offset;
 203                 strncpy(attr->u.kprobe.symbol_name,
 204                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 205                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 206                 break;
 207         case LTTNG_EVENT_FUNCTION:
 208                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 209                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 210                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 211                 strncpy(attr->u.kretprobe.symbol_name,
 212                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 213                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 214                 break;
 215         case LTTNG_EVENT_FUNCTION_ENTRY:
 216                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 217                 strncpy(attr->u.ftrace.symbol_name,
 218                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 219                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 220                 break;
 221         case LTTNG_EVENT_TRACEPOINT:
 222                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 223                 break;
 224         case LTTNG_EVENT_SYSCALL:
 225                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 226                 break;
 227         case LTTNG_EVENT_ALL:
 228                 attr->instrumentation = LTTNG_KERNEL_ALL;
 229                 break;
 230         default:
 231                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 232                 goto error;
 233         }
 234
 235         /* Copy event name */
 236         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 237         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 238
 239         /* Setting up a kernel event */
 240         lke->fd = -1;
 241         lke->event = attr;
 242         lke->enabled = 1;
 243
 244         return lke;
 245
 246 error:
 247         free(lke);
 248         free(attr);
 249         return NULL;
 250 }
 251
 252 /*
 253  * Allocate and initialize a kernel metadata.
 254  *
 255  * Return pointer to structure or NULL.
 256  */
 257 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 258 {
 259         struct ltt_kernel_metadata *lkm;
 260         struct lttng_channel *chan;
 261
 262         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 263         chan = zmalloc(sizeof(struct lttng_channel));
 264         if (lkm == NULL || chan == NULL) {
 265                 PERROR("kernel metadata zmalloc");
 266                 goto error;
 267         }
 268
 269         /* Set default attributes */
 270         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 271         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 272         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 273         chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
 274         chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
 275         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 276
 277         /* Init metadata */
 278         lkm->fd = -1;
 279         lkm->conf = chan;
 280
 281         return lkm;
 282
 283 error:
 284         free(lkm);
 285         free(chan);
 286         return NULL;
 287 }
 288
 289 /*
 290  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 291  * default.
 292  *
 293  * Return pointer to structure or NULL.
 294  */
 295 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 296                 unsigned int count)
 297 {
 298         int ret;
 299         struct ltt_kernel_stream *lks;
 300
 301         assert(name);
 302
 303         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 304         if (lks == NULL) {
 305                 PERROR("kernel stream zmalloc");
 306                 goto error;
 307         }
 308
 309         /* Set name */
 310         ret = snprintf(lks->name, sizeof(lks->name), "%s_%d", name, count);
 311         if (ret < 0) {
 312                 PERROR("snprintf stream name");
 313                 goto error;
 314         }
 315         lks->name[sizeof(lks->name) - 1] = '\0';
 316
 317         /* Init stream */
 318         lks->fd = -1;
 319         lks->state = 0;
 320         lks->cpu = count;
 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         assert(stream);
 334
 335         DBG("[trace] Closing stream fd %d", stream->fd);
 336         /* Close kernel fd */
 337         if (stream->fd >= 0) {
 338                 int ret;
 339
 340                 ret = close(stream->fd);
 341                 if (ret) {
 342                         PERROR("close");
 343                 }
 344         }
 345         /* Remove from stream list */
 346         cds_list_del(&stream->list);
 347
 348         free(stream);
 349 }
 350
 351 /*
 352  * Cleanup kernel event structure.
 353  */
 354 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 355 {
 356         assert(event);
 357
 358         if (event->fd >= 0) {
 359                 int ret;
 360
 361                 DBG("[trace] Closing event fd %d", event->fd);
 362                 /* Close kernel fd */
 363                 ret = close(event->fd);
 364                 if (ret) {
 365                         PERROR("close");
 366                 }
 367         } else {
 368                 DBG("[trace] Tearing down event (no associated fd)");
 369         }
 370
 371         /* Remove from event list */
 372         cds_list_del(&event->list);
 373
 374         free(event->event);
 375         free(event);
 376 }
 377
 378 /*
 379  * Cleanup kernel channel structure.
 380  */
 381 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 382 {
 383         struct ltt_kernel_stream *stream, *stmp;
 384         struct ltt_kernel_event *event, *etmp;
 385         int ret;
 386
 387         assert(channel);
 388
 389         DBG("[trace] Closing channel fd %d", channel->fd);
 390         /* Close kernel fd */
 391         if (channel->fd >= 0) {
 392                 ret = close(channel->fd);
 393                 if (ret) {
 394                         PERROR("close");
 395                 }
 396         }
 397
 398         /* For each stream in the channel list */
 399         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 400                 trace_kernel_destroy_stream(stream);
 401         }
 402
 403         /* For each event in the channel list */
 404         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 405                 trace_kernel_destroy_event(event);
 406         }
 407
 408         /* Remove from channel list */
 409         cds_list_del(&channel->list);
 410
 411         free(channel->channel);
 412         free(channel->ctx);
 413         free(channel);
 414 }
 415
 416 /*
 417  * Cleanup kernel metadata structure.
 418  */
 419 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 420 {
 421         assert(metadata);
 422
 423         DBG("[trace] Closing metadata fd %d", metadata->fd);
 424         /* Close kernel fd */
 425         if (metadata->fd >= 0) {
 426                 int ret;
 427
 428                 ret = close(metadata->fd);
 429                 if (ret) {
 430                         PERROR("close");
 431                 }
 432         }
 433
 434         free(metadata->conf);
 435         free(metadata);
 436 }
 437
 438 /*
 439  * Cleanup kernel session structure
 440  *
 441  * Should *NOT* be called with RCU read-side lock held.
 442  */
 443 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 444 {
 445         struct ltt_kernel_channel *channel, *ctmp;
 446         int ret;
 447
 448         assert(session);
 449
 450         DBG("[trace] Closing session fd %d", session->fd);
 451         /* Close kernel fds */
 452         if (session->fd >= 0) {
 453                 ret = close(session->fd);
 454                 if (ret) {
 455                         PERROR("close");
 456                 }
 457         }
 458
 459         if (session->metadata_stream_fd >= 0) {
 460                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 461                 ret = close(session->metadata_stream_fd);
 462                 if (ret) {
 463                         PERROR("close");
 464                 }
 465         }
 466
 467         if (session->metadata != NULL) {
 468                 trace_kernel_destroy_metadata(session->metadata);
 469         }
 470
 471         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 472                 trace_kernel_destroy_channel(channel);
 473         }
 474
 475         /* Wipe consumer output object */
 476         consumer_destroy_output(session->consumer);
 477         consumer_destroy_output(session->tmp_consumer);
 478
 479         free(session);
 480 }