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         return NULL;
 232 }
 233
 234 /*
 235  * Allocate and initialize a kernel metadata.
 236  *
 237  * Return pointer to structure or NULL.
 238  */
 239 struct ltt_kernel_metadata *trace_kernel_create_metadata(char *path)
 240 {
 241         int ret;
 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_METADATA_SUBBUF_SIZE;
 255         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 256         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 257         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 258         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 259
 260         /* Init metadata */
 261         lkm->fd = -1;
 262         lkm->conf = chan;
 263         /* Set default metadata path */
 264         ret = asprintf(&lkm->pathname, "%s/metadata", path);
 265         if (ret < 0) {
 266                 PERROR("asprintf kernel metadata");
 267                 goto error;
 268         }
 269
 270         return lkm;
 271
 272 error:
 273         return NULL;
 274 }
 275
 276 /*
 277  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 278  * default.
 279  *
 280  * Return pointer to structure or NULL.
 281  */
 282 struct ltt_kernel_stream *trace_kernel_create_stream(void)
 283 {
 284         struct ltt_kernel_stream *lks;
 285
 286         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 287         if (lks == NULL) {
 288                 PERROR("kernel stream zmalloc");
 289                 goto error;
 290         }
 291
 292         /* Init stream */
 293         lks->fd = -1;
 294         lks->pathname = NULL;
 295         lks->state = 0;
 296
 297         return lks;
 298
 299 error:
 300         return NULL;
 301 }
 302
 303 /*
 304  * Cleanup kernel stream structure.
 305  */
 306 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 307 {
 308         int ret;
 309
 310         DBG("[trace] Closing stream fd %d", stream->fd);
 311         /* Close kernel fd */
 312         if (stream->fd >= 0) {
 313                 ret = close(stream->fd);
 314                 if (ret) {
 315                         PERROR("close");
 316                 }
 317         }
 318         /* Remove from stream list */
 319         cds_list_del(&stream->list);
 320
 321         free(stream->pathname);
 322         free(stream);
 323 }
 324
 325 /*
 326  * Cleanup kernel event structure.
 327  */
 328 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 329 {
 330         int ret;
 331
 332         if (event->fd >= 0) {
 333                 DBG("[trace] Closing event fd %d", event->fd);
 334                 /* Close kernel fd */
 335                 ret = close(event->fd);
 336                 if (ret) {
 337                         PERROR("close");
 338                 }
 339         } else {
 340                 DBG("[trace] Tearing down event (no associated fd)");
 341         }
 342
 343         /* Remove from event list */
 344         cds_list_del(&event->list);
 345
 346         free(event->event);
 347         free(event->ctx);
 348         free(event);
 349 }
 350
 351 /*
 352  * Cleanup kernel channel structure.
 353  */
 354 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 355 {
 356         struct ltt_kernel_stream *stream, *stmp;
 357         struct ltt_kernel_event *event, *etmp;
 358         int ret;
 359
 360         DBG("[trace] Closing channel fd %d", channel->fd);
 361         /* Close kernel fd */
 362         if (channel->fd >= 0) {
 363                 ret = close(channel->fd);
 364                 if (ret) {
 365                         PERROR("close");
 366                 }
 367         }
 368
 369         /* For each stream in the channel list */
 370         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 371                 trace_kernel_destroy_stream(stream);
 372         }
 373
 374         /* For each event in the channel list */
 375         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 376                 trace_kernel_destroy_event(event);
 377         }
 378
 379         /* Remove from channel list */
 380         cds_list_del(&channel->list);
 381
 382         free(channel->pathname);
 383         free(channel->channel);
 384         free(channel->ctx);
 385         free(channel);
 386 }
 387
 388 /*
 389  * Cleanup kernel metadata structure.
 390  */
 391 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 392 {
 393         int ret;
 394
 395         DBG("[trace] Closing metadata fd %d", metadata->fd);
 396         /* Close kernel fd */
 397         if (metadata->fd >= 0) {
 398                 ret = close(metadata->fd);
 399                 if (ret) {
 400                         PERROR("close");
 401                 }
 402         }
 403
 404         free(metadata->conf);
 405         free(metadata->pathname);
 406         free(metadata);
 407 }
 408
 409 /*
 410  * Cleanup kernel session structure
 411  */
 412 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 413 {
 414         struct ltt_kernel_channel *channel, *ctmp;
 415         int ret;
 416
 417         DBG("[trace] Closing session fd %d", session->fd);
 418         /* Close kernel fds */
 419         if (session->fd >= 0) {
 420                 ret = close(session->fd);
 421                 if (ret) {
 422                         PERROR("close");
 423                 }
 424         }
 425
 426         if (session->metadata_stream_fd >= 0) {
 427                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 428                 ret = close(session->metadata_stream_fd);
 429                 if (ret) {
 430                         PERROR("close");
 431                 }
 432         }
 433
 434         if (session->metadata != NULL) {
 435                 trace_kernel_destroy_metadata(session->metadata);
 436         }
 437
 438         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 439                 trace_kernel_destroy_channel(channel);
 440         }
 441
 442         free(session->trace_path);
 443         free(session);
 444 }