src/common/kernel-ctl/kernel-ctl.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *               2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #define __USE_LINUX_IOCTL_DEFS
  22 #include <sys/ioctl.h>
  23 #include <string.h>
  24 #include <common/align.h>
  25 #include <errno.h>
  26 #include <stdarg.h>
  27 #include <assert.h>
  28
  29 #include "kernel-ctl.h"
  30 #include "kernel-ioctl.h"
  31
  32 #define LTTNG_IOCTL_CHECK(fildes, request, ...) ({      \
  33         int ret = ioctl(fildes, request, ##__VA_ARGS__);\
  34         assert(ret <= 0);                               \
  35         !ret ? 0 : -errno;                              \
  36 })
  37
  38 #define LTTNG_IOCTL_NO_CHECK(fildes, request, ...) ({   \
  39         int ret = ioctl(fildes, request, ##__VA_ARGS__);\
  40         ret >= 0 ? ret : -errno;                        \
  41 })
  42
  43 /*
  44  * This flag indicates which version of the kernel ABI to use. The old
  45  * ABI (namespace _old) does not support a 32-bit user-space when the
  46  * kernel is 64-bit. The old ABI is kept here for compatibility but is
  47  * deprecated and will be removed eventually.
  48  */
  49 static int lttng_kernel_use_old_abi = -1;
  50
  51 /*
  52  * Execute the new or old ioctl depending on the ABI version.
  53  * If the ABI version is not determined yet (lttng_kernel_use_old_abi = -1),
  54  * this function tests if the new ABI is available and otherwise fallbacks
  55  * on the old one.
  56  * This function takes the fd on which the ioctl must be executed and the old
  57  * and new request codes.
  58  * It returns the return value of the ioctl executed.
  59  */
  60 static inline int compat_ioctl_no_arg(int fd, unsigned long oldname,
  61                 unsigned long newname)
  62 {
  63         int ret;
  64
  65         if (lttng_kernel_use_old_abi == -1) {
  66                 ret = LTTNG_IOCTL_NO_CHECK(fd, newname);
  67                 if (!ret) {
  68                         lttng_kernel_use_old_abi = 0;
  69                         goto end;
  70                 }
  71                 lttng_kernel_use_old_abi = 1;
  72         }
  73         if (lttng_kernel_use_old_abi) {
  74                 ret = LTTNG_IOCTL_NO_CHECK(fd, oldname);
  75         } else {
  76                 ret = LTTNG_IOCTL_NO_CHECK(fd, newname);
  77         }
  78
  79 end:
  80         return ret;
  81 }
  82
  83 int kernctl_create_session(int fd)
  84 {
  85         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION,
  86                         LTTNG_KERNEL_SESSION);
  87 }
  88
  89 /* open the metadata global channel */
  90 int kernctl_open_metadata(int fd, struct lttng_channel_attr *chops)
  91 {
  92         struct lttng_kernel_channel channel;
  93
  94         if (lttng_kernel_use_old_abi) {
  95                 struct lttng_kernel_old_channel old_channel;
  96
  97                 memset(&old_channel, 0, sizeof(old_channel));
  98                 old_channel.overwrite = chops->overwrite;
  99                 old_channel.subbuf_size = chops->subbuf_size;
 100                 old_channel.num_subbuf = chops->num_subbuf;
 101                 old_channel.switch_timer_interval = chops->switch_timer_interval;
 102                 old_channel.read_timer_interval = chops->read_timer_interval;
 103                 old_channel.output = chops->output;
 104
 105                 memset(old_channel.padding, 0, sizeof(old_channel.padding));
 106                 /*
 107                  * The new channel padding is smaller than the old ABI so we use the
 108                  * new ABI padding size for the memcpy.
 109                  */
 110                 memcpy(old_channel.padding, chops->padding, sizeof(chops->padding));
 111
 112                 return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_METADATA,
 113                                 &old_channel);
 114         }
 115
 116         memset(&channel, 0, sizeof(channel));
 117         channel.overwrite = chops->overwrite;
 118         channel.subbuf_size = chops->subbuf_size;
 119         channel.num_subbuf = chops->num_subbuf;
 120         channel.switch_timer_interval = chops->switch_timer_interval;
 121         channel.read_timer_interval = chops->read_timer_interval;
 122         channel.output = chops->output;
 123         memcpy(channel.padding, chops->padding, sizeof(chops->padding));
 124
 125         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_METADATA, &channel);
 126 }
 127
 128 int kernctl_create_channel(int fd, struct lttng_channel_attr *chops)
 129 {
 130         struct lttng_kernel_channel channel;
 131
 132         memset(&channel, 0, sizeof(channel));
 133         if (lttng_kernel_use_old_abi) {
 134                 struct lttng_kernel_old_channel old_channel;
 135
 136                 old_channel.overwrite = chops->overwrite;
 137                 old_channel.subbuf_size = chops->subbuf_size;
 138                 old_channel.num_subbuf = chops->num_subbuf;
 139                 old_channel.switch_timer_interval = chops->switch_timer_interval;
 140                 old_channel.read_timer_interval = chops->read_timer_interval;
 141                 old_channel.output = chops->output;
 142
 143                 memset(old_channel.padding, 0, sizeof(old_channel.padding));
 144                 /*
 145                  * The new channel padding is smaller than the old ABI so we use the
 146                  * new ABI padding size for the memcpy.
 147                  */
 148                 memcpy(old_channel.padding, chops->padding, sizeof(chops->padding));
 149
 150                 return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_CHANNEL,
 151                                 &old_channel);
 152         }
 153
 154         channel.overwrite = chops->overwrite;
 155         channel.subbuf_size = chops->subbuf_size;
 156         channel.num_subbuf = chops->num_subbuf;
 157         channel.switch_timer_interval = chops->switch_timer_interval;
 158         channel.read_timer_interval = chops->read_timer_interval;
 159         channel.output = chops->output;
 160         memcpy(channel.padding, chops->padding, sizeof(chops->padding));
 161
 162         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_CHANNEL, &channel);
 163 }
 164
 165 int kernctl_syscall_mask(int fd, char **syscall_mask, uint32_t *nr_bits)
 166 {
 167         struct lttng_kernel_syscall_mask kmask_len, *kmask = NULL;
 168         size_t array_alloc_len;
 169         char *new_mask;
 170         int ret = 0;
 171
 172         if (!syscall_mask) {
 173                 ret = -1;
 174                 goto end;
 175         }
 176
 177         if (!nr_bits) {
 178                 ret = -1;
 179                 goto end;
 180         }
 181
 182         kmask_len.len = 0;
 183         ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SYSCALL_MASK, &kmask_len);
 184         if (ret) {
 185                 goto end;
 186         }
 187
 188         array_alloc_len = ALIGN(kmask_len.len, 8) >> 3;
 189
 190         kmask = zmalloc(sizeof(*kmask) + array_alloc_len);
 191         if (!kmask) {
 192                 ret = -1;
 193                 goto end;
 194         }
 195
 196         kmask->len = kmask_len.len;
 197         ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SYSCALL_MASK, kmask);
 198         if (ret) {
 199                 goto end;
 200         }
 201
 202         new_mask = realloc(*syscall_mask, array_alloc_len);
 203         if (!new_mask) {
 204                 ret = -1;
 205                 goto end;
 206         }
 207         memcpy(new_mask, kmask->mask, array_alloc_len);
 208         *syscall_mask = new_mask;
 209         *nr_bits = kmask->len;
 210
 211 end:
 212         free(kmask);
 213         return ret;
 214 }
 215
 216 int kernctl_track_pid(int fd, int pid)
 217 {
 218         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_TRACK_PID, pid);
 219 }
 220
 221 int kernctl_untrack_pid(int fd, int pid)
 222 {
 223         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_UNTRACK_PID, pid);
 224 }
 225
 226 int kernctl_list_tracker_pids(int fd)
 227 {
 228         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS);
 229 }
 230
 231 int kernctl_session_regenerate_metadata(int fd)
 232 {
 233         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_METADATA_REGEN);
 234 }
 235
 236 int kernctl_session_regenerate_statedump(int fd)
 237 {
 238         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_STATEDUMP);
 239 }
 240
 241 int kernctl_session_set_name(int fd, const char *name)
 242 {
 243         struct lttng_kernel_session_name session_name;
 244
 245         strncpy(session_name.name, name, LTTNG_KERNEL_SESSION_NAME_LEN);
 246
 247         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_SET_NAME,
 248                         &session_name);
 249 }
 250
 251 int kernctl_create_stream(int fd)
 252 {
 253         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_STREAM,
 254                         LTTNG_KERNEL_STREAM);
 255 }
 256
 257 int kernctl_create_event(int fd, struct lttng_kernel_event *ev)
 258 {
 259         if (lttng_kernel_use_old_abi) {
 260                 struct lttng_kernel_old_event old_event;
 261
 262                 memset(&old_event, 0, sizeof(old_event));
 263                 memcpy(old_event.name, ev->name, sizeof(old_event.name));
 264                 old_event.instrumentation = ev->instrumentation;
 265                 switch (ev->instrumentation) {
 266                 case LTTNG_KERNEL_KPROBE:
 267                         old_event.u.kprobe.addr = ev->u.kprobe.addr;
 268                         old_event.u.kprobe.offset = ev->u.kprobe.offset;
 269                         memcpy(old_event.u.kprobe.symbol_name,
 270                                 ev->u.kprobe.symbol_name,
 271                                 sizeof(old_event.u.kprobe.symbol_name));
 272                         break;
 273                 case LTTNG_KERNEL_KRETPROBE:
 274                         old_event.u.kretprobe.addr = ev->u.kretprobe.addr;
 275                         old_event.u.kretprobe.offset = ev->u.kretprobe.offset;
 276                         memcpy(old_event.u.kretprobe.symbol_name,
 277                                 ev->u.kretprobe.symbol_name,
 278                                 sizeof(old_event.u.kretprobe.symbol_name));
 279                         break;
 280                 case LTTNG_KERNEL_FUNCTION:
 281                         memcpy(old_event.u.ftrace.symbol_name,
 282                                         ev->u.ftrace.symbol_name,
 283                                         sizeof(old_event.u.ftrace.symbol_name));
 284                         break;
 285                 default:
 286                         break;
 287                 }
 288
 289                 return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_EVENT,
 290                                 &old_event);
 291         }
 292         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_EVENT, ev);
 293 }
 294
 295 int kernctl_add_context(int fd, struct lttng_kernel_context *ctx)
 296 {
 297         if (lttng_kernel_use_old_abi) {
 298                 struct lttng_kernel_old_context old_ctx;
 299
 300                 memset(&old_ctx, 0, sizeof(old_ctx));
 301                 old_ctx.ctx = ctx->ctx;
 302                 /* only type that uses the union */
 303                 if (ctx->ctx == LTTNG_KERNEL_CONTEXT_PERF_CPU_COUNTER) {
 304                         old_ctx.u.perf_counter.type =
 305                                 ctx->u.perf_counter.type;
 306                         old_ctx.u.perf_counter.config =
 307                                 ctx->u.perf_counter.config;
 308                         memcpy(old_ctx.u.perf_counter.name,
 309                                 ctx->u.perf_counter.name,
 310                                 sizeof(old_ctx.u.perf_counter.name));
 311                 }
 312                 return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_OLD_CONTEXT, &old_ctx);
 313         }
 314         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_CONTEXT, ctx);
 315 }
 316
 317
 318 /* Enable event, channel and session LTTNG_IOCTL_CHECK */
 319 int kernctl_enable(int fd)
 320 {
 321         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_ENABLE,
 322                         LTTNG_KERNEL_ENABLE);
 323 }
 324
 325 /* Disable event, channel and session LTTNG_IOCTL_CHECK */
 326 int kernctl_disable(int fd)
 327 {
 328         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_DISABLE,
 329                         LTTNG_KERNEL_DISABLE);
 330 }
 331
 332 int kernctl_start_session(int fd)
 333 {
 334         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION_START,
 335                         LTTNG_KERNEL_SESSION_START);
 336 }
 337
 338 int kernctl_stop_session(int fd)
 339 {
 340         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION_STOP,
 341                         LTTNG_KERNEL_SESSION_STOP);
 342 }
 343
 344 int kernctl_filter(int fd, struct lttng_filter_bytecode *filter)
 345 {
 346         struct lttng_kernel_filter_bytecode *kb;
 347         uint32_t len;
 348         int ret;
 349
 350         /* Translate bytecode to kernel bytecode */
 351         kb = zmalloc(sizeof(*kb) + filter->len);
 352         if (!kb)
 353                 return -ENOMEM;
 354         kb->len = len = filter->len;
 355         kb->reloc_offset = filter->reloc_table_offset;
 356         kb->seqnum = filter->seqnum;
 357         memcpy(kb->data, filter->data, len);
 358         ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_FILTER, kb);
 359         free(kb);
 360         return ret;
 361 }
 362
 363 int kernctl_add_callsite(int fd, struct lttng_kernel_event_callsite *callsite)
 364 {
 365         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_ADD_CALLSITE, callsite);
 366 }
 367
 368 int kernctl_tracepoint_list(int fd)
 369 {
 370         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_TRACEPOINT_LIST,
 371                         LTTNG_KERNEL_TRACEPOINT_LIST);
 372 }
 373
 374 int kernctl_syscall_list(int fd)
 375 {
 376         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_SYSCALL_LIST);
 377 }
 378
 379 int kernctl_tracer_version(int fd, struct lttng_kernel_tracer_version *v)
 380 {
 381         int ret;
 382
 383         if (lttng_kernel_use_old_abi == -1) {
 384                 ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_VERSION, v);
 385                 if (!ret) {
 386                         lttng_kernel_use_old_abi = 0;
 387                         goto end;
 388                 }
 389                 lttng_kernel_use_old_abi = 1;
 390         }
 391         if (lttng_kernel_use_old_abi) {
 392                 struct lttng_kernel_old_tracer_version old_v;
 393
 394                 ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_OLD_TRACER_VERSION, &old_v);
 395                 if (ret) {
 396                         goto end;
 397                 }
 398                 v->major = old_v.major;
 399                 v->minor = old_v.minor;
 400                 v->patchlevel = old_v.patchlevel;
 401         } else {
 402                 ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_VERSION, v);
 403         }
 404
 405 end:
 406         return ret;
 407 }
 408
 409 int kernctl_tracer_abi_version(int fd,
 410                 struct lttng_kernel_tracer_abi_version *v)
 411 {
 412         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_ABI_VERSION, v);
 413 }
 414
 415 int kernctl_wait_quiescent(int fd)
 416 {
 417         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_WAIT_QUIESCENT,
 418                         LTTNG_KERNEL_WAIT_QUIESCENT);
 419 }
 420
 421 int kernctl_buffer_flush(int fd)
 422 {
 423         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_FLUSH);
 424 }
 425
 426 int kernctl_buffer_flush_empty(int fd)
 427 {
 428         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_FLUSH_EMPTY);
 429 }
 430
 431 /* returns the version of the metadata. */
 432 int kernctl_get_metadata_version(int fd, uint64_t *version)
 433 {
 434         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_METADATA_VERSION, version);
 435 }
 436
 437 int kernctl_metadata_cache_dump(int fd)
 438 {
 439         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_METADATA_CACHE_DUMP);
 440 }
 441
 442 /* Buffer operations */
 443
 444 /* For mmap mode, readable without "get" operation */
 445
 446 /* returns the length to mmap. */
 447 int kernctl_get_mmap_len(int fd, unsigned long *len)
 448 {
 449         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MMAP_LEN, len);
 450 }
 451
 452 /* returns the maximum size for sub-buffers. */
 453 int kernctl_get_max_subbuf_size(int fd, unsigned long *len)
 454 {
 455         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MAX_SUBBUF_SIZE, len);
 456 }
 457
 458 /*
 459  * For mmap mode, operate on the current packet (between get/put or
 460  * get_next/put_next).
 461  */
 462
 463 /* returns the offset of the subbuffer belonging to the mmap reader. */
 464 int kernctl_get_mmap_read_offset(int fd, unsigned long *off)
 465 {
 466         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MMAP_READ_OFFSET, off);
 467 }
 468
 469 /* returns the size of the current sub-buffer, without padding (for mmap). */
 470 int kernctl_get_subbuf_size(int fd, unsigned long *len)
 471 {
 472         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_SUBBUF_SIZE, len);
 473 }
 474
 475 /* returns the size of the current sub-buffer, without padding (for mmap). */
 476 int kernctl_get_padded_subbuf_size(int fd, unsigned long *len)
 477 {
 478         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_PADDED_SUBBUF_SIZE, len);
 479 }
 480
 481 /* Get exclusive read access to the next sub-buffer that can be read. */
 482 int kernctl_get_next_subbuf(int fd)
 483 {
 484         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_NEXT_SUBBUF);
 485 }
 486
 487
 488 /* Release exclusive sub-buffer access, move consumer forward. */
 489 int kernctl_put_next_subbuf(int fd)
 490 {
 491         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_PUT_NEXT_SUBBUF);
 492 }
 493
 494 /* snapshot */
 495
 496 /* Get a snapshot of the current ring buffer producer and consumer positions */
 497 int kernctl_snapshot(int fd)
 498 {
 499         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT);
 500 }
 501
 502 /*
 503  * Get a snapshot of the current ring buffer producer and consumer positions,
 504  * regardless of whether or not the two positions are contained within the
 505  * same sub-buffer.
 506  */
 507 int kernctl_snapshot_sample_positions(int fd)
 508 {
 509         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS);
 510 }
 511
 512 /* Get the consumer position (iteration start) */
 513 int kernctl_snapshot_get_consumed(int fd, unsigned long *pos)
 514 {
 515         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_GET_CONSUMED, pos);
 516 }
 517
 518 /* Get the producer position (iteration end) */
 519 int kernctl_snapshot_get_produced(int fd, unsigned long *pos)
 520 {
 521         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_GET_PRODUCED, pos);
 522 }
 523
 524 /* Get exclusive read access to the specified sub-buffer position */
 525 int kernctl_get_subbuf(int fd, unsigned long *len)
 526 {
 527         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_SUBBUF, len);
 528 }
 529
 530 /* Release exclusive sub-buffer access */
 531 int kernctl_put_subbuf(int fd)
 532 {
 533         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_PUT_SUBBUF);
 534 }
 535
 536 /* Returns the timestamp begin of the current sub-buffer. */
 537 int kernctl_get_timestamp_begin(int fd, uint64_t *timestamp_begin)
 538 {
 539         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN,
 540                         timestamp_begin);
 541 }
 542
 543 /* Returns the timestamp end of the current sub-buffer. */
 544 int kernctl_get_timestamp_end(int fd, uint64_t *timestamp_end)
 545 {
 546         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_TIMESTAMP_END,
 547                         timestamp_end);
 548 }
 549
 550 /* Returns the number of discarded events in the current sub-buffer. */
 551 int kernctl_get_events_discarded(int fd, uint64_t *events_discarded)
 552 {
 553         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED,
 554                         events_discarded);
 555 }
 556
 557 /* Returns the content size in the current sub-buffer. */
 558 int kernctl_get_content_size(int fd, uint64_t *content_size)
 559 {
 560         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_CONTENT_SIZE,
 561                         content_size);
 562 }
 563
 564 /* Returns the packet size in the current sub-buffer. */
 565 int kernctl_get_packet_size(int fd, uint64_t *packet_size)
 566 {
 567         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_PACKET_SIZE,
 568                         packet_size);
 569 }
 570
 571 /* Returns the stream id of the current sub-buffer. */
 572 int kernctl_get_stream_id(int fd, uint64_t *stream_id)
 573 {
 574         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_STREAM_ID,
 575                         stream_id);
 576 }
 577
 578 /* Returns the current timestamp. */
 579 int kernctl_get_current_timestamp(int fd, uint64_t *ts)
 580 {
 581         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP,
 582                         ts);
 583 }
 584
 585 /* Returns the packet sequence number of the current sub-buffer. */
 586 int kernctl_get_sequence_number(int fd, uint64_t *seq)
 587 {
 588         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_SEQ_NUM, seq);
 589 }
 590
 591 /* Returns the stream instance id. */
 592 int kernctl_get_instance_id(int fd, uint64_t *id)
 593 {
 594         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_INSTANCE_ID, id);
 595 }