ltt-sessiond/kernel-ctl.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
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include "lttngerr.h"
  28 #include "ltt-sessiond.h"
  29 #include "libkernelctl.h"
  30 #include "kernel-ctl.h"
  31
  32 /*
  33  *  kernel_create_session
  34  *
  35  *  Create a new kernel session, register it to the kernel tracer and add it to
  36  *  the session daemon session.
  37  */
  38 int kernel_create_session(struct ltt_session *session, int tracer_fd)
  39 {
  40         int ret;
  41         struct ltt_kernel_session *lks;
  42
  43         /* Allocate data structure */
  44         lks = trace_create_kernel_session();
  45         if (lks == NULL) {
  46                 ret = -1;
  47                 goto error;
  48         }
  49
  50         /* Kernel tracer session creation */
  51         ret = kernctl_create_session(tracer_fd);
  52         if (ret < 0) {
  53                 perror("ioctl kernel create session");
  54                 goto error;
  55         }
  56
  57         lks->fd = ret;
  58         /* Prevent fd duplication after execlp() */
  59         ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
  60         if (ret < 0) {
  61                 perror("fcntl session fd");
  62         }
  63
  64         lks->kconsumer_fds_sent = 0;
  65         session->kernel_session = lks;
  66         session->kern_session_count++;
  67
  68         DBG("Kernel session created (fd: %d)", lks->fd);
  69
  70         return 0;
  71
  72 error:
  73         return ret;
  74 }
  75
  76 /*
  77  *  kernel_create_channel
  78  *
  79  *  Create a kernel channel, register it to the kernel tracer and add it to the
  80  *  kernel session.
  81  */
  82 int kernel_create_channel(struct ltt_kernel_session *session, struct lttng_channel *chan)
  83 {
  84         int ret;
  85         struct ltt_kernel_channel *lkc;
  86
  87         /* Allocate kernel channel */
  88         lkc = trace_create_kernel_channel(chan);
  89         if (lkc == NULL) {
  90                 goto error;
  91         }
  92
  93         /* Kernel tracer channel creation */
  94         ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
  95         if (ret < 0) {
  96                 perror("ioctl kernel create channel");
  97                 goto error;
  98         }
  99
 100         /* Setup the channel fd */
 101         lkc->fd = ret;
 102         /* Prevent fd duplication after execlp() */
 103         ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
 104         if (ret < 0) {
 105                 perror("fcntl session fd");
 106         }
 107
 108         /* Add channel to session */
 109         cds_list_add(&lkc->list, &session->channel_list.head);
 110         session->channel_count++;
 111
 112         DBG("Kernel channel %s created (fd: %d and path: %s)",
 113                         lkc->channel->name, lkc->fd, lkc->pathname);
 114
 115         return 0;
 116
 117 error:
 118         return -1;
 119 }
 120
 121 /*
 122  *  kernel_create_event
 123  *
 124  *  Create a kernel event, enable it to the kernel tracer and add it to the
 125  *  channel event list of the kernel session.
 126  */
 127 int kernel_create_event(struct lttng_event *ev, struct ltt_kernel_channel *channel)
 128 {
 129         int ret;
 130         struct ltt_kernel_event *event;
 131
 132         event = trace_create_kernel_event(ev);
 133         if (event == NULL) {
 134                 goto error;
 135         }
 136
 137         ret = kernctl_create_event(channel->fd, event->event);
 138         if (ret < 0) {
 139                 perror("create event ioctl");
 140                 goto free_event;
 141         }
 142
 143         event->fd = ret;
 144         /* Prevent fd duplication after execlp() */
 145         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 146         if (ret < 0) {
 147                 perror("fcntl session fd");
 148         }
 149
 150         /* Add event to event list */
 151         cds_list_add(&event->list, &channel->events_list.head);
 152         DBG("Event %s created (fd: %d)", ev->name, event->fd);
 153
 154         return 0;
 155
 156 free_event:
 157         free(event);
 158 error:
 159         return -1;
 160 }
 161
 162 /*
 163  *  kernel_enable_channel
 164  *
 165  *  Enable a kernel channel.
 166  */
 167 int kernel_enable_channel(struct ltt_kernel_channel *chan)
 168 {
 169         int ret;
 170
 171         ret = kernctl_enable(chan->fd);
 172         if (ret < 0) {
 173                 perror("enable chan ioctl");
 174                 ret = errno;
 175                 goto error;
 176         }
 177
 178         chan->enabled = 1;
 179         DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
 180
 181         return 0;
 182
 183 error:
 184         return ret;
 185 }
 186
 187 /*
 188  *  kernel_enable_event
 189  *
 190  *  Enable a kernel event.
 191  */
 192 int kernel_enable_event(struct ltt_kernel_event *event)
 193 {
 194         int ret;
 195
 196         ret = kernctl_enable(event->fd);
 197         if (ret < 0) {
 198                 perror("enable event ioctl");
 199                 goto error;
 200         }
 201
 202         event->enabled = 1;
 203         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 204
 205         return 0;
 206
 207 error:
 208         return ret;
 209 }
 210
 211 /*
 212  *  kernel_disable_event
 213  *
 214  *  Disable a kernel event.
 215  */
 216 int kernel_disable_event(struct ltt_kernel_event *event)
 217 {
 218         int ret;
 219
 220         ret = kernctl_disable(event->fd);
 221         if (ret < 0) {
 222                 perror("disable event ioctl");
 223                 goto error;
 224         }
 225
 226         event->enabled = 0;
 227         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 228
 229         return 0;
 230
 231 error:
 232         return ret;
 233 }
 234
 235 /*
 236  *  kernel_open_metadata
 237  *
 238  *  Create kernel metadata, open from the kernel tracer and add it to the
 239  *  kernel session.
 240  */
 241 int kernel_open_metadata(struct ltt_kernel_session *session)
 242 {
 243         int ret;
 244         struct ltt_kernel_metadata *lkm;
 245
 246         /* Allocate kernel metadata */
 247         lkm = trace_create_kernel_metadata();
 248         if (lkm == NULL) {
 249                 goto error;
 250         }
 251
 252         /* Kernel tracer metadata creation */
 253         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 254         if (ret < 0) {
 255                 goto error;
 256         }
 257
 258         lkm->fd = ret;
 259         /* Prevent fd duplication after execlp() */
 260         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 261         if (ret < 0) {
 262                 perror("fcntl session fd");
 263         }
 264
 265         session->metadata = lkm;
 266
 267         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 268
 269         return 0;
 270
 271 error:
 272         return -1;
 273 }
 274
 275 /*
 276  *  kernel_start_session
 277  *
 278  *  Start tracing session.
 279  */
 280 int kernel_start_session(struct ltt_kernel_session *session)
 281 {
 282         int ret;
 283
 284         ret = kernctl_start_session(session->fd);
 285         if (ret < 0) {
 286                 perror("ioctl start session");
 287                 goto error;
 288         }
 289
 290         DBG("Kernel session started");
 291
 292         return 0;
 293
 294 error:
 295         return ret;
 296 }
 297
 298 /*
 299  *  kernel_wait_quiescent
 300  *
 301  *  Make a kernel wait to make sure in-flight probe have completed.
 302  */
 303 void kernel_wait_quiescent(int fd)
 304 {
 305         int ret;
 306
 307         DBG("Kernel quiescent wait on %d", fd);
 308
 309         ret = kernctl_wait_quiescent(fd);
 310         if (ret < 0) {
 311                 perror("wait quiescent ioctl");
 312                 ERR("Kernel quiescent wait failed");
 313         }
 314 }
 315
 316 /*
 317  *  kernel_metadata_flush_buffer
 318  *
 319  *  Force flush buffer of metadata.
 320  */
 321 int kernel_metadata_flush_buffer(int fd)
 322 {
 323         int ret;
 324
 325         ret = kernctl_buffer_flush(fd);
 326         if (ret < 0) {
 327                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 328         }
 329
 330         return 0;
 331 }
 332
 333 /*
 334  *  kernel_flush_buffer
 335  *
 336  *  Force flush buffer for channel.
 337  */
 338 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 339 {
 340         int ret;
 341         struct ltt_kernel_stream *stream;
 342
 343         DBG("Flush buffer for channel %s", channel->channel->name);
 344
 345         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 346                 DBG("Flushing channel stream %d", stream->fd);
 347                 ret = kernctl_buffer_flush(stream->fd);
 348                 if (ret < 0) {
 349                         perror("ioctl");
 350                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 351                                         stream->fd, ret);
 352                 }
 353         }
 354
 355         return 0;
 356 }
 357
 358 /*
 359  *  kernel_stop_session
 360  *
 361  *  Stop tracing session.
 362  */
 363 int kernel_stop_session(struct ltt_kernel_session *session)
 364 {
 365         int ret;
 366
 367         ret = kernctl_stop_session(session->fd);
 368         if (ret < 0) {
 369                 goto error;
 370         }
 371
 372         DBG("Kernel session stopped");
 373
 374         return 0;
 375
 376 error:
 377         return ret;
 378 }
 379
 380 /*
 381  *  kernel_open_channel_stream
 382  *
 383  *  Open stream of channel, register it to the kernel tracer and add it
 384  *  to the stream list of the channel.
 385  *
 386  *  Return the number of created stream. Else, a negative value.
 387  */
 388 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 389 {
 390         int ret;
 391         struct ltt_kernel_stream *lks;
 392
 393         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 394                 lks = trace_create_kernel_stream();
 395                 if (lks == NULL) {
 396                         close(ret);
 397                         goto error;
 398                 }
 399
 400                 lks->fd = ret;
 401                 /* Prevent fd duplication after execlp() */
 402                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 403                 if (ret < 0) {
 404                         perror("fcntl session fd");
 405                 }
 406
 407                 ret = asprintf(&lks->pathname, "%s/trace_%d",
 408                                 channel->pathname, channel->stream_count);
 409                 if (ret < 0) {
 410                         perror("asprintf kernel create stream");
 411                         goto error;
 412                 }
 413
 414                 /* Add stream to channe stream list */
 415                 cds_list_add(&lks->list, &channel->stream_list.head);
 416                 channel->stream_count++;
 417
 418                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 419                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 420         }
 421
 422         return channel->stream_count;
 423
 424 error:
 425         return -1;
 426 }
 427
 428 /*
 429  *  kernel_open_metadata_stream
 430  *
 431  *  Open the metadata stream and set it to the kernel session.
 432  */
 433 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 434 {
 435         int ret;
 436
 437         ret = kernctl_create_stream(session->metadata->fd);
 438         if (ret < 0) {
 439                 perror("kernel create metadata stream");
 440                 goto error;
 441         }
 442
 443         DBG("Kernel metadata stream created (fd: %d)", ret);
 444         session->metadata_stream_fd = ret;
 445         /* Prevent fd duplication after execlp() */
 446         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 447         if (ret < 0) {
 448                 perror("fcntl session fd");
 449         }
 450
 451         return 0;
 452
 453 error:
 454         return -1;
 455 }
 456
 457 /*
 458  *  kernel_list_events
 459  *
 460  *  Get the event list from the kernel tracer and return that list in the CTF
 461  *  format.
 462  */
 463 ssize_t kernel_list_events(int tracer_fd, char **list)
 464 {
 465         int fd;
 466         char *buf, *line = NULL;
 467         size_t nb, nbmem, total = 0;
 468         ssize_t size;
 469         FILE *fp;
 470
 471         fd = kernctl_tracepoint_list(tracer_fd);
 472         if (fd < 0) {
 473                 perror("kernel tracepoint list");
 474                 goto error;
 475         }
 476
 477         fp = fdopen(fd, "r");
 478         if (fp == NULL) {
 479                 perror("kernel tracepoint list fdopen");
 480                 goto error;
 481         }
 482
 483         /*
 484          * Init memory size counter
 485          * See kernel-ctl.h for explanation of this value
 486          */
 487         nbmem = KERNEL_EVENT_LIST_SIZE;
 488         buf = malloc(nbmem);
 489
 490         while ((size = getline(&line, &nb, fp)) != -1) {
 491                 if (total + size > nbmem) {
 492                         DBG("Reallocating event list from %zd to %zd bytes", nbmem,
 493                                         total + size + KERNEL_EVENT_LIST_SIZE);
 494                         /* Adding the default size again */
 495                         nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
 496                         buf = realloc(buf, nbmem);
 497                         if (buf == NULL) {
 498                                 perror("realloc list events");
 499                                 goto error;
 500                         }
 501                 }
 502                 memcpy(buf + total, line, size);
 503                 total += size;
 504         }
 505
 506         *list = buf;
 507
 508         DBG("Kernel list events done");
 509
 510         return total;
 511
 512 error:
 513         return -1;
 514 }