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; only version 2
   7  * of the License.
   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 <lttng-kernel-ctl.h>
  28 #include <lttngerr.h>
  29
  30 #include "kernel-ctl.h"
  31
  32 /*
  33  * Add context on a kernel channel.
  34  */
  35 int kernel_add_channel_context(struct ltt_kernel_channel *chan,
  36                 struct lttng_kernel_context *ctx)
  37 {
  38         int ret;
  39
  40         DBG("Adding context to channel %s", chan->channel->name);
  41         ret = kernctl_add_context(chan->fd, ctx);
  42         if (ret < 0) {
  43                 if (errno != EEXIST) {
  44                         perror("add context ioctl");
  45                 } else {
  46                         /* If EEXIST, we just ignore the error */
  47                         ret = 0;
  48                 }
  49                 goto error;
  50         }
  51
  52         chan->ctx = malloc(sizeof(struct lttng_kernel_context));
  53         if (chan->ctx == NULL) {
  54                 perror("malloc event context");
  55                 goto error;
  56         }
  57
  58         memcpy(chan->ctx, ctx, sizeof(struct lttng_kernel_context));
  59
  60         return 0;
  61
  62 error:
  63         return ret;
  64 }
  65
  66 /*
  67  * Add context on a kernel event.
  68  */
  69 int kernel_add_event_context(struct ltt_kernel_event *event,
  70                 struct lttng_kernel_context *ctx)
  71 {
  72         int ret;
  73
  74         DBG("Adding context to event %s", event->event->name);
  75         ret = kernctl_add_context(event->fd, ctx);
  76         if (ret < 0) {
  77                 perror("add context ioctl");
  78                 goto error;
  79         }
  80
  81         event->ctx = malloc(sizeof(struct lttng_kernel_context));
  82         if (event->ctx == NULL) {
  83                 perror("malloc event context");
  84                 goto error;
  85         }
  86
  87         memcpy(event->ctx, ctx, sizeof(struct lttng_kernel_context));
  88
  89         return 0;
  90
  91 error:
  92         return ret;
  93 }
  94
  95 /*
  96  * Create a new kernel session, register it to the kernel tracer and add it to
  97  * the session daemon session.
  98  */
  99 int kernel_create_session(struct ltt_session *session, int tracer_fd)
 100 {
 101         int ret;
 102         struct ltt_kernel_session *lks;
 103
 104         /* Allocate data structure */
 105         lks = trace_kernel_create_session(session->path);
 106         if (lks == NULL) {
 107                 ret = -1;
 108                 goto error;
 109         }
 110
 111         /* Kernel tracer session creation */
 112         ret = kernctl_create_session(tracer_fd);
 113         if (ret < 0) {
 114                 perror("ioctl kernel create session");
 115                 goto error;
 116         }
 117
 118         lks->fd = ret;
 119         /* Prevent fd duplication after execlp() */
 120         ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 121         if (ret < 0) {
 122                 perror("fcntl session fd");
 123         }
 124
 125         lks->kconsumer_fds_sent = 0;
 126         session->kernel_session = lks;
 127
 128         DBG("Kernel session created (fd: %d)", lks->fd);
 129
 130         return 0;
 131
 132 error:
 133         return ret;
 134 }
 135
 136 /*
 137  * Create a kernel channel, register it to the kernel tracer and add it to the
 138  * kernel session.
 139  */
 140 int kernel_create_channel(struct ltt_kernel_session *session,
 141                 struct lttng_channel *chan, char *path)
 142 {
 143         int ret;
 144         struct ltt_kernel_channel *lkc;
 145
 146         /* Allocate kernel channel */
 147         lkc = trace_kernel_create_channel(chan, path);
 148         if (lkc == NULL) {
 149                 goto error;
 150         }
 151
 152         /* Kernel tracer channel creation */
 153         ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
 154         if (ret < 0) {
 155                 perror("ioctl kernel create channel");
 156                 goto error;
 157         }
 158
 159         /* Setup the channel fd */
 160         lkc->fd = ret;
 161         /* Prevent fd duplication after execlp() */
 162         ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
 163         if (ret < 0) {
 164                 perror("fcntl session fd");
 165         }
 166
 167         /* Add channel to session */
 168         cds_list_add(&lkc->list, &session->channel_list.head);
 169         session->channel_count++;
 170
 171         DBG("Kernel channel %s created (fd: %d and path: %s)",
 172                         lkc->channel->name, lkc->fd, lkc->pathname);
 173
 174         return 0;
 175
 176 error:
 177         return -1;
 178 }
 179
 180 /*
 181  * Create a kernel event, enable it to the kernel tracer and add it to the
 182  * channel event list of the kernel session.
 183  */
 184 int kernel_create_event(struct lttng_event *ev,
 185                 struct ltt_kernel_channel *channel)
 186 {
 187         int ret;
 188         struct ltt_kernel_event *event;
 189
 190         event = trace_kernel_create_event(ev);
 191         if (event == NULL) {
 192                 goto error;
 193         }
 194
 195         ret = kernctl_create_event(channel->fd, event->event);
 196         if (ret < 0) {
 197                 perror("create event ioctl");
 198                 goto free_event;
 199         }
 200
 201         event->fd = ret;
 202         /* Prevent fd duplication after execlp() */
 203         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 204         if (ret < 0) {
 205                 perror("fcntl session fd");
 206         }
 207
 208         /* Add event to event list */
 209         cds_list_add(&event->list, &channel->events_list.head);
 210         channel->event_count++;
 211
 212         DBG("Event %s created (fd: %d)", ev->name, event->fd);
 213
 214         return 0;
 215
 216 free_event:
 217         free(event);
 218 error:
 219         return -1;
 220 }
 221
 222 /*
 223  * Disable a kernel channel.
 224  */
 225 int kernel_disable_channel(struct ltt_kernel_channel *chan)
 226 {
 227         int ret;
 228
 229         ret = kernctl_disable(chan->fd);
 230         if (ret < 0) {
 231                 perror("disable chan ioctl");
 232                 ret = errno;
 233                 goto error;
 234         }
 235
 236         chan->enabled = 0;
 237         DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
 238
 239         return 0;
 240
 241 error:
 242         return ret;
 243 }
 244
 245 /*
 246  * Enable a kernel channel.
 247  */
 248 int kernel_enable_channel(struct ltt_kernel_channel *chan)
 249 {
 250         int ret;
 251
 252         ret = kernctl_enable(chan->fd);
 253         if (ret < 0 && errno != EEXIST) {
 254                 perror("Enable kernel chan");
 255                 goto error;
 256         }
 257
 258         chan->enabled = 1;
 259         DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
 260
 261         return 0;
 262
 263 error:
 264         return ret;
 265 }
 266
 267 /*
 268  * Enable a kernel event.
 269  */
 270 int kernel_enable_event(struct ltt_kernel_event *event)
 271 {
 272         int ret;
 273
 274         ret = kernctl_enable(event->fd);
 275         if (ret < 0 && errno != EEXIST) {
 276                 perror("enable kernel event");
 277                 goto error;
 278         }
 279
 280         event->enabled = 1;
 281         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 282
 283         return 0;
 284
 285 error:
 286         return ret;
 287 }
 288
 289 /*
 290  * Disable a kernel event.
 291  */
 292 int kernel_disable_event(struct ltt_kernel_event *event)
 293 {
 294         int ret;
 295
 296         ret = kernctl_disable(event->fd);
 297         if (ret < 0 && errno != EEXIST) {
 298                 perror("disable kernel event");
 299                 goto error;
 300         }
 301
 302         event->enabled = 0;
 303         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 304
 305         return 0;
 306
 307 error:
 308         return ret;
 309 }
 310
 311 /*
 312  * Create kernel metadata, open from the kernel tracer and add it to the
 313  * kernel session.
 314  */
 315 int kernel_open_metadata(struct ltt_kernel_session *session, char *path)
 316 {
 317         int ret;
 318         struct ltt_kernel_metadata *lkm;
 319
 320         /* Allocate kernel metadata */
 321         lkm = trace_kernel_create_metadata(path);
 322         if (lkm == NULL) {
 323                 goto error;
 324         }
 325
 326         /* Kernel tracer metadata creation */
 327         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 328         if (ret < 0) {
 329                 goto error;
 330         }
 331
 332         lkm->fd = ret;
 333         /* Prevent fd duplication after execlp() */
 334         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 335         if (ret < 0) {
 336                 perror("fcntl session fd");
 337         }
 338
 339         session->metadata = lkm;
 340
 341         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 342
 343         return 0;
 344
 345 error:
 346         return -1;
 347 }
 348
 349 /*
 350  * Start tracing session.
 351  */
 352 int kernel_start_session(struct ltt_kernel_session *session)
 353 {
 354         int ret;
 355
 356         ret = kernctl_start_session(session->fd);
 357         if (ret < 0) {
 358                 perror("ioctl start session");
 359                 goto error;
 360         }
 361
 362         DBG("Kernel session started");
 363
 364         return 0;
 365
 366 error:
 367         return ret;
 368 }
 369
 370 /*
 371  * Make a kernel wait to make sure in-flight probe have completed.
 372  */
 373 void kernel_wait_quiescent(int fd)
 374 {
 375         int ret;
 376
 377         DBG("Kernel quiescent wait on %d", fd);
 378
 379         ret = kernctl_wait_quiescent(fd);
 380         if (ret < 0) {
 381                 perror("wait quiescent ioctl");
 382                 ERR("Kernel quiescent wait failed");
 383         }
 384 }
 385
 386 /*
 387  * Kernel calibrate
 388  */
 389 int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate)
 390 {
 391         int ret;
 392
 393         ret = kernctl_calibrate(fd, calibrate);
 394         if (ret < 0) {
 395                 perror("calibrate ioctl");
 396                 return -1;
 397         }
 398
 399         return 0;
 400 }
 401
 402
 403 /*
 404  *  Force flush buffer of metadata.
 405  */
 406 int kernel_metadata_flush_buffer(int fd)
 407 {
 408         int ret;
 409
 410         ret = kernctl_buffer_flush(fd);
 411         if (ret < 0) {
 412                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 413         }
 414
 415         return 0;
 416 }
 417
 418 /*
 419  * Force flush buffer for channel.
 420  */
 421 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 422 {
 423         int ret;
 424         struct ltt_kernel_stream *stream;
 425
 426         DBG("Flush buffer for channel %s", channel->channel->name);
 427
 428         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 429                 DBG("Flushing channel stream %d", stream->fd);
 430                 ret = kernctl_buffer_flush(stream->fd);
 431                 if (ret < 0) {
 432                         perror("ioctl");
 433                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 434                                         stream->fd, ret);
 435                 }
 436         }
 437
 438         return 0;
 439 }
 440
 441 /*
 442  * Stop tracing session.
 443  */
 444 int kernel_stop_session(struct ltt_kernel_session *session)
 445 {
 446         int ret;
 447
 448         ret = kernctl_stop_session(session->fd);
 449         if (ret < 0) {
 450                 goto error;
 451         }
 452
 453         DBG("Kernel session stopped");
 454
 455         return 0;
 456
 457 error:
 458         return ret;
 459 }
 460
 461 /*
 462  * Open stream of channel, register it to the kernel tracer and add it
 463  * to the stream list of the channel.
 464  *
 465  * Return the number of created stream. Else, a negative value.
 466  */
 467 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 468 {
 469         int ret;
 470         struct ltt_kernel_stream *lks;
 471
 472         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 473                 lks = trace_kernel_create_stream();
 474                 if (lks == NULL) {
 475                         close(ret);
 476                         goto error;
 477                 }
 478
 479                 lks->fd = ret;
 480                 /* Prevent fd duplication after execlp() */
 481                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 482                 if (ret < 0) {
 483                         perror("fcntl session fd");
 484                 }
 485
 486                 ret = asprintf(&lks->pathname, "%s/%s_%d",
 487                                 channel->pathname, channel->channel->name, channel->stream_count);
 488                 if (ret < 0) {
 489                         perror("asprintf kernel create stream");
 490                         goto error;
 491                 }
 492
 493                 /* Add stream to channe stream list */
 494                 cds_list_add(&lks->list, &channel->stream_list.head);
 495                 channel->stream_count++;
 496
 497                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 498                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 499         }
 500
 501         return channel->stream_count;
 502
 503 error:
 504         return -1;
 505 }
 506
 507 /*
 508  * Open the metadata stream and set it to the kernel session.
 509  */
 510 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 511 {
 512         int ret;
 513
 514         ret = kernctl_create_stream(session->metadata->fd);
 515         if (ret < 0) {
 516                 perror("kernel create metadata stream");
 517                 goto error;
 518         }
 519
 520         DBG("Kernel metadata stream created (fd: %d)", ret);
 521         session->metadata_stream_fd = ret;
 522         /* Prevent fd duplication after execlp() */
 523         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 524         if (ret < 0) {
 525                 perror("fcntl session fd");
 526         }
 527
 528         return 0;
 529
 530 error:
 531         return -1;
 532 }
 533
 534 /*
 535  * Get the event list from the kernel tracer and return the number of elements.
 536  */
 537 ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 538 {
 539         int fd, pos;
 540         char *event;
 541         size_t nbmem, count = 0;
 542         ssize_t size;
 543         FILE *fp;
 544         struct lttng_event *elist;
 545
 546         fd = kernctl_tracepoint_list(tracer_fd);
 547         if (fd < 0) {
 548                 perror("kernel tracepoint list");
 549                 goto error;
 550         }
 551
 552         fp = fdopen(fd, "r");
 553         if (fp == NULL) {
 554                 perror("kernel tracepoint list fdopen");
 555                 goto error_fp;
 556         }
 557
 558         /*
 559          * Init memory size counter
 560          * See kernel-ctl.h for explanation of this value
 561          */
 562         nbmem = KERNEL_EVENT_LIST_SIZE;
 563         elist = malloc(sizeof(struct lttng_event) * nbmem);
 564
 565         while ((size = fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos)) == 1) {
 566                 if (count > nbmem) {
 567                         DBG("Reallocating event list from %zu to %zu bytes", nbmem,
 568                                         nbmem + KERNEL_EVENT_LIST_SIZE);
 569                         /* Adding the default size again */
 570                         nbmem += KERNEL_EVENT_LIST_SIZE;
 571                         elist = realloc(elist, nbmem);
 572                         if (elist == NULL) {
 573                                 perror("realloc list events");
 574                                 count = -ENOMEM;
 575                                 goto end;
 576                         }
 577                 }
 578                 strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
 579                 elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 580                 count++;
 581         }
 582
 583         *events = elist;
 584         DBG("Kernel list events done (%zu events)", count);
 585 end:
 586         fclose(fp);     /* closes both fp and fd */
 587         return count;
 588
 589 error_fp:
 590         close(fd);
 591 error:
 592         return -1;
 593 }