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 "trace-kernel.h"
  28
  29 /*
  30  * Find the channel name for the given kernel session.
  31  */
  32 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
  33                 char *name, struct ltt_kernel_session *session)
  34 {
  35         struct ltt_kernel_channel *chan;
  36
  37         if (session == NULL) {
  38                 ERR("Undefine session");
  39                 goto error;
  40         }
  41
  42         DBG("Trying to find channel %s", name);
  43
  44         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  45                 if (strcmp(name, chan->channel->name) == 0) {
  46                         DBG("Found channel by name %s", name);
  47                         return chan;
  48                 }
  49         }
  50
  51 error:
  52         return NULL;
  53 }
  54
  55 /*
  56  * Find the event name for the given channel.
  57  */
  58 struct ltt_kernel_event *trace_kernel_get_event_by_name(
  59                 char *name, struct ltt_kernel_channel *channel)
  60 {
  61         struct ltt_kernel_event *ev;
  62
  63         if (channel == NULL) {
  64                 ERR("Undefine channel");
  65                 goto error;
  66         }
  67
  68         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  69                 if (strcmp(name, ev->event->name) == 0) {
  70                         DBG("Found event by name %s for channel %s", name,
  71                                         channel->channel->name);
  72                         return ev;
  73                 }
  74         }
  75
  76 error:
  77         return NULL;
  78 }
  79
  80 /*
  81  * Allocate and initialize a kernel session data structure.
  82  *
  83  * Return pointer to structure or NULL.
  84  */
  85 struct ltt_kernel_session *trace_kernel_create_session(char *path)
  86 {
  87         int ret;
  88         struct ltt_kernel_session *lks;
  89
  90         /* Allocate a new ltt kernel session */
  91         lks = zmalloc(sizeof(struct ltt_kernel_session));
  92         if (lks == NULL) {
  93                 PERROR("create kernel session zmalloc");
  94                 goto error;
  95         }
  96
  97         /* Init data structure */
  98         lks->fd = -1;
  99         lks->metadata_stream_fd = -1;
 100         lks->channel_count = 0;
 101         lks->stream_count_global = 0;
 102         lks->metadata = NULL;
 103         lks->consumer_fd = -1;
 104         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 105
 106         /* Set session path */
 107         ret = asprintf(&lks->trace_path, "%s/kernel", path);
 108         if (ret < 0) {
 109                 PERROR("asprintf kernel traces path");
 110                 goto error;
 111         }
 112
 113         return lks;
 114
 115 error:
 116         return NULL;
 117 }
 118
 119 /*
 120  * Allocate and initialize a kernel channel data structure.
 121  *
 122  * Return pointer to structure or NULL.
 123  */
 124 struct ltt_kernel_channel *trace_kernel_create_channel(struct lttng_channel *chan, char *path)
 125 {
 126         int ret;
 127         struct ltt_kernel_channel *lkc;
 128
 129         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 130         if (lkc == NULL) {
 131                 PERROR("ltt_kernel_channel zmalloc");
 132                 goto error;
 133         }
 134
 135         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 136         if (lkc->channel == NULL) {
 137                 PERROR("lttng_channel zmalloc");
 138                 goto error;
 139         }
 140         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 141
 142         lkc->fd = -1;
 143         lkc->stream_count = 0;
 144         lkc->event_count = 0;
 145         lkc->enabled = 1;
 146         lkc->ctx = NULL;
 147         /* Init linked list */
 148         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 149         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 150         /* Set default trace output path */
 151         ret = asprintf(&lkc->pathname, "%s", path);
 152         if (ret < 0) {
 153                 PERROR("asprintf kernel create channel");
 154                 goto error;
 155         }
 156
 157         return lkc;
 158
 159 error:
 160         return NULL;
 161 }
 162
 163 /*
 164  * Allocate and initialize a kernel event. Set name and event type.
 165  *
 166  * Return pointer to structure or NULL.
 167  */
 168 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 169 {
 170         struct ltt_kernel_event *lke;
 171         struct lttng_kernel_event *attr;
 172
 173         lke = zmalloc(sizeof(struct ltt_kernel_event));
 174         attr = zmalloc(sizeof(struct lttng_kernel_event));
 175         if (lke == NULL || attr == NULL) {
 176                 PERROR("kernel event zmalloc");
 177                 goto error;
 178         }
 179
 180         switch (ev->type) {
 181         case LTTNG_EVENT_PROBE:
 182                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 183                 attr->u.kprobe.addr = ev->attr.probe.addr;
 184                 attr->u.kprobe.offset = ev->attr.probe.offset;
 185                 strncpy(attr->u.kprobe.symbol_name,
 186                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 187                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 188                 break;
 189         case LTTNG_EVENT_FUNCTION:
 190                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 191                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 192                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 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         lke->ctx = NULL;
 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(char *path)
 242 {
 243         int ret;
 244         struct ltt_kernel_metadata *lkm;
 245         struct lttng_channel *chan;
 246
 247         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 248         chan = zmalloc(sizeof(struct lttng_channel));
 249         if (lkm == NULL || chan == NULL) {
 250                 PERROR("kernel metadata zmalloc");
 251                 goto error;
 252         }
 253
 254         /* Set default attributes */
 255         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 256         chan->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
 257         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 258         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 259         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 260         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 261
 262         /* Init metadata */
 263         lkm->fd = -1;
 264         lkm->conf = chan;
 265         /* Set default metadata path */
 266         ret = asprintf(&lkm->pathname, "%s/metadata", path);
 267         if (ret < 0) {
 268                 PERROR("asprintf kernel metadata");
 269                 goto error;
 270         }
 271
 272         return lkm;
 273
 274 error:
 275         free(lkm);
 276         free(chan);
 277         return NULL;
 278 }
 279
 280 /*
 281  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 282  * default.
 283  *
 284  * Return pointer to structure or NULL.
 285  */
 286 struct ltt_kernel_stream *trace_kernel_create_stream(void)
 287 {
 288         struct ltt_kernel_stream *lks;
 289
 290         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 291         if (lks == NULL) {
 292                 PERROR("kernel stream zmalloc");
 293                 goto error;
 294         }
 295
 296         /* Init stream */
 297         lks->fd = -1;
 298         lks->pathname = NULL;
 299         lks->state = 0;
 300
 301         return lks;
 302
 303 error:
 304         return NULL;
 305 }
 306
 307 /*
 308  * Cleanup kernel stream structure.
 309  */
 310 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 311 {
 312         int ret;
 313
 314         DBG("[trace] Closing stream fd %d", stream->fd);
 315         /* Close kernel fd */
 316         if (stream->fd >= 0) {
 317                 ret = close(stream->fd);
 318                 if (ret) {
 319                         PERROR("close");
 320                 }
 321         }
 322         /* Remove from stream list */
 323         cds_list_del(&stream->list);
 324
 325         free(stream->pathname);
 326         free(stream);
 327 }
 328
 329 /*
 330  * Cleanup kernel event structure.
 331  */
 332 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 333 {
 334         int ret;
 335
 336         if (event->fd >= 0) {
 337                 DBG("[trace] Closing event fd %d", event->fd);
 338                 /* Close kernel fd */
 339                 ret = close(event->fd);
 340                 if (ret) {
 341                         PERROR("close");
 342                 }
 343         } else {
 344                 DBG("[trace] Tearing down event (no associated fd)");
 345         }
 346
 347         /* Remove from event list */
 348         cds_list_del(&event->list);
 349
 350         free(event->event);
 351         free(event->ctx);
 352         free(event);
 353 }
 354
 355 /*
 356  * Cleanup kernel channel structure.
 357  */
 358 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 359 {
 360         struct ltt_kernel_stream *stream, *stmp;
 361         struct ltt_kernel_event *event, *etmp;
 362         int ret;
 363
 364         DBG("[trace] Closing channel fd %d", channel->fd);
 365         /* Close kernel fd */
 366         if (channel->fd >= 0) {
 367                 ret = close(channel->fd);
 368                 if (ret) {
 369                         PERROR("close");
 370                 }
 371         }
 372
 373         /* For each stream in the channel list */
 374         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 375                 trace_kernel_destroy_stream(stream);
 376         }
 377
 378         /* For each event in the channel list */
 379         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 380                 trace_kernel_destroy_event(event);
 381         }
 382
 383         /* Remove from channel list */
 384         cds_list_del(&channel->list);
 385
 386         free(channel->pathname);
 387         free(channel->channel);
 388         free(channel->ctx);
 389         free(channel);
 390 }
 391
 392 /*
 393  * Cleanup kernel metadata structure.
 394  */
 395 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 396 {
 397         int ret;
 398
 399         DBG("[trace] Closing metadata fd %d", metadata->fd);
 400         /* Close kernel fd */
 401         if (metadata->fd >= 0) {
 402                 ret = close(metadata->fd);
 403                 if (ret) {
 404                         PERROR("close");
 405                 }
 406         }
 407
 408         free(metadata->conf);
 409         free(metadata->pathname);
 410         free(metadata);
 411 }
 412
 413 /*
 414  * Cleanup kernel session structure
 415  */
 416 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 417 {
 418         struct ltt_kernel_channel *channel, *ctmp;
 419         int ret;
 420
 421         DBG("[trace] Closing session fd %d", session->fd);
 422         /* Close kernel fds */
 423         if (session->fd >= 0) {
 424                 ret = close(session->fd);
 425                 if (ret) {
 426                         PERROR("close");
 427                 }
 428         }
 429
 430         if (session->metadata_stream_fd >= 0) {
 431                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 432                 ret = close(session->metadata_stream_fd);
 433                 if (ret) {
 434                         PERROR("close");
 435                 }
 436         }
 437
 438         if (session->metadata != NULL) {
 439                 trace_kernel_destroy_metadata(session->metadata);
 440         }
 441
 442         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 443                 trace_kernel_destroy_channel(channel);
 444         }
 445
 446         free(session->trace_path);
 447         free(session);
 448 }