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 <common/macros.h>
  26 #include <errno.h>
  27 #include <stdarg.h>
  28 #include <assert.h>
  29
  30 #include "kernel-ctl.h"
  31 #include "kernel-ioctl.h"
  32
  33 #define LTTNG_IOCTL_CHECK(fildes, request, ...) ({      \
  34         int ret = ioctl(fildes, request, ##__VA_ARGS__);\
  35         assert(ret <= 0);                               \
  36         !ret ? 0 : -errno;                              \
  37 })
  38
  39 #define LTTNG_IOCTL_NO_CHECK(fildes, request, ...) ({   \
  40         int ret = ioctl(fildes, request, ##__VA_ARGS__);\
  41         ret >= 0 ? ret : -errno;                        \
  42 })
  43
  44 /*
  45  * This flag indicates which version of the kernel ABI to use. The old
  46  * ABI (namespace _old) does not support a 32-bit user-space when the
  47  * kernel is 64-bit. The old ABI is kept here for compatibility but is
  48  * deprecated and will be removed eventually.
  49  */
  50 static int lttng_kernel_use_old_abi = -1;
  51
  52 /*
  53  * Execute the new or old ioctl depending on the ABI version.
  54  * If the ABI version is not determined yet (lttng_kernel_use_old_abi = -1),
  55  * this function tests if the new ABI is available and otherwise fallbacks
  56  * on the old one.
  57  * This function takes the fd on which the ioctl must be executed and the old
  58  * and new request codes.
  59  * It returns the return value of the ioctl executed.
  60  */
  61 static inline int compat_ioctl_no_arg(int fd, unsigned long oldname,
  62                 unsigned long newname)
  63 {
  64         int ret;
  65
  66         if (lttng_kernel_use_old_abi == -1) {
  67                 ret = LTTNG_IOCTL_NO_CHECK(fd, newname);
  68                 if (!ret) {
  69                         lttng_kernel_use_old_abi = 0;
  70                         goto end;
  71                 }
  72                 lttng_kernel_use_old_abi = 1;
  73         }
  74         if (lttng_kernel_use_old_abi) {
  75                 ret = LTTNG_IOCTL_NO_CHECK(fd, oldname);
  76         } else {
  77                 ret = LTTNG_IOCTL_NO_CHECK(fd, newname);
  78         }
  79
  80 end:
  81         return ret;
  82 }
  83
  84 int kernctl_create_session(int fd)
  85 {
  86         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION,
  87                         LTTNG_KERNEL_SESSION);
  88 }
  89
  90 /* open the metadata global channel */
  91 int kernctl_open_metadata(int fd, struct lttng_channel_attr *chops)
  92 {
  93         struct lttng_kernel_channel channel;
  94
  95         if (lttng_kernel_use_old_abi) {
  96                 struct lttng_kernel_old_channel old_channel;
  97
  98                 memset(&old_channel, 0, sizeof(old_channel));
  99                 old_channel.overwrite = chops->overwrite;
 100                 old_channel.subbuf_size = chops->subbuf_size;
 101                 old_channel.num_subbuf = chops->num_subbuf;
 102                 old_channel.switch_timer_interval = chops->switch_timer_interval;
 103                 old_channel.read_timer_interval = chops->read_timer_interval;
 104                 old_channel.output = chops->output;
 105
 106                 memset(old_channel.padding, 0, sizeof(old_channel.padding));
 107                 /*
 108                  * The new channel padding is smaller than the old ABI so we use the
 109                  * new ABI padding size for the memcpy.
 110                  */
 111                 memcpy(old_channel.padding, chops->padding, sizeof(chops->padding));
 112
 113                 return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_METADATA,
 114                                 &old_channel);
 115         }
 116
 117         memset(&channel, 0, sizeof(channel));
 118         channel.overwrite = chops->overwrite;
 119         channel.subbuf_size = chops->subbuf_size;
 120         channel.num_subbuf = chops->num_subbuf;
 121         channel.switch_timer_interval = chops->switch_timer_interval;
 122         channel.read_timer_interval = chops->read_timer_interval;
 123         channel.output = chops->output;
 124         memcpy(channel.padding, chops->padding, sizeof(chops->padding));
 125
 126         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_METADATA, &channel);
 127 }
 128
 129 int kernctl_create_channel(int fd, struct lttng_channel_attr *chops)
 130 {
 131         struct lttng_kernel_channel channel;
 132
 133         memset(&channel, 0, sizeof(channel));
 134         if (lttng_kernel_use_old_abi) {
 135                 struct lttng_kernel_old_channel old_channel;
 136
 137                 old_channel.overwrite = chops->overwrite;
 138                 old_channel.subbuf_size = chops->subbuf_size;
 139                 old_channel.num_subbuf = chops->num_subbuf;
 140                 old_channel.switch_timer_interval = chops->switch_timer_interval;
 141                 old_channel.read_timer_interval = chops->read_timer_interval;
 142                 old_channel.output = chops->output;
 143
 144                 memset(old_channel.padding, 0, sizeof(old_channel.padding));
 145                 /*
 146                  * The new channel padding is smaller than the old ABI so we use the
 147                  * new ABI padding size for the memcpy.
 148                  */
 149                 memcpy(old_channel.padding, chops->padding, sizeof(chops->padding));
 150
 151                 return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_CHANNEL,
 152                                 &old_channel);
 153         }
 154
 155         channel.overwrite = chops->overwrite;
 156         channel.subbuf_size = chops->subbuf_size;
 157         channel.num_subbuf = chops->num_subbuf;
 158         channel.switch_timer_interval = chops->switch_timer_interval;
 159         channel.read_timer_interval = chops->read_timer_interval;
 160         channel.output = chops->output;
 161         memcpy(channel.padding, chops->padding, sizeof(chops->padding));
 162
 163         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_CHANNEL, &channel);
 164 }
 165
 166 int kernctl_syscall_mask(int fd, char **syscall_mask, uint32_t *nr_bits)
 167 {
 168         struct lttng_kernel_syscall_mask kmask_len, *kmask = NULL;
 169         size_t array_alloc_len;
 170         char *new_mask;
 171         int ret = 0;
 172
 173         if (!syscall_mask) {
 174                 ret = -1;
 175                 goto end;
 176         }
 177
 178         if (!nr_bits) {
 179                 ret = -1;
 180                 goto end;
 181         }
 182
 183         kmask_len.len = 0;
 184         ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SYSCALL_MASK, &kmask_len);
 185         if (ret) {
 186                 goto end;
 187         }
 188
 189         array_alloc_len = ALIGN(kmask_len.len, 8) >> 3;
 190
 191         kmask = zmalloc(sizeof(*kmask) + array_alloc_len);
 192         if (!kmask) {
 193                 ret = -1;
 194                 goto end;
 195         }
 196
 197         kmask->len = kmask_len.len;
 198         ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SYSCALL_MASK, kmask);
 199         if (ret) {
 200                 goto end;
 201         }
 202
 203         new_mask = realloc(*syscall_mask, array_alloc_len);
 204         if (!new_mask) {
 205                 ret = -1;
 206                 goto end;
 207         }
 208         memcpy(new_mask, kmask->mask, array_alloc_len);
 209         *syscall_mask = new_mask;
 210         *nr_bits = kmask->len;
 211
 212 end:
 213         free(kmask);
 214         return ret;
 215 }
 216
 217 int kernctl_track_pid(int fd, int pid)
 218 {
 219         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_TRACK_PID, pid);
 220 }
 221
 222 int kernctl_untrack_pid(int fd, int pid)
 223 {
 224         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_UNTRACK_PID, pid);
 225 }
 226
 227 int kernctl_list_tracker_pids(int fd)
 228 {
 229         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS);
 230 }
 231
 232 int kernctl_session_regenerate_metadata(int fd)
 233 {
 234         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_METADATA_REGEN);
 235 }
 236
 237 int kernctl_session_regenerate_statedump(int fd)
 238 {
 239         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_STATEDUMP);
 240 }
 241
 242 int kernctl_session_set_name(int fd, const char *name)
 243 {
 244         int ret;
 245         struct lttng_kernel_session_name session_name;
 246
 247         ret = lttng_strncpy(session_name.name, name, sizeof(session_name.name));
 248         if (ret) {
 249                 goto end;
 250         }
 251
 252         ret = LTTNG_IOCTL_CHECK(
 253                         fd, LTTNG_KERNEL_SESSION_SET_NAME, &session_name);
 254 end:
 255         return ret;
 256 }
 257
 258 int kernctl_create_stream(int fd)
 259 {
 260         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_STREAM,
 261                         LTTNG_KERNEL_STREAM);
 262 }
 263
 264 int kernctl_create_event(int fd, struct lttng_kernel_event *ev)
 265 {
 266         if (lttng_kernel_use_old_abi) {
 267                 struct lttng_kernel_old_event old_event;
 268
 269                 memset(&old_event, 0, sizeof(old_event));
 270                 memcpy(old_event.name, ev->name, sizeof(old_event.name));
 271                 old_event.instrumentation = ev->instrumentation;
 272                 switch (ev->instrumentation) {
 273                 case LTTNG_KERNEL_KPROBE:
 274                         old_event.u.kprobe.addr = ev->u.kprobe.addr;
 275                         old_event.u.kprobe.offset = ev->u.kprobe.offset;
 276                         memcpy(old_event.u.kprobe.symbol_name,
 277                                 ev->u.kprobe.symbol_name,
 278                                 sizeof(old_event.u.kprobe.symbol_name));
 279                         break;
 280                 case LTTNG_KERNEL_KRETPROBE:
 281                         old_event.u.kretprobe.addr = ev->u.kretprobe.addr;
 282                         old_event.u.kretprobe.offset = ev->u.kretprobe.offset;
 283                         memcpy(old_event.u.kretprobe.symbol_name,
 284                                 ev->u.kretprobe.symbol_name,
 285                                 sizeof(old_event.u.kretprobe.symbol_name));
 286                         break;
 287                 case LTTNG_KERNEL_FUNCTION:
 288                         memcpy(old_event.u.ftrace.symbol_name,
 289                                         ev->u.ftrace.symbol_name,
 290                                         sizeof(old_event.u.ftrace.symbol_name));
 291                         break;
 292                 default:
 293                         break;
 294                 }
 295
 296                 return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_OLD_EVENT,
 297                                 &old_event);
 298         }
 299         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_EVENT, ev);
 300 }
 301
 302 int kernctl_add_context(int fd, struct lttng_kernel_context *ctx)
 303 {
 304         if (lttng_kernel_use_old_abi) {
 305                 struct lttng_kernel_old_context old_ctx;
 306
 307                 memset(&old_ctx, 0, sizeof(old_ctx));
 308                 old_ctx.ctx = ctx->ctx;
 309                 /* only type that uses the union */
 310                 if (ctx->ctx == LTTNG_KERNEL_CONTEXT_PERF_CPU_COUNTER) {
 311                         old_ctx.u.perf_counter.type =
 312                                 ctx->u.perf_counter.type;
 313                         old_ctx.u.perf_counter.config =
 314                                 ctx->u.perf_counter.config;
 315                         memcpy(old_ctx.u.perf_counter.name,
 316                                 ctx->u.perf_counter.name,
 317                                 sizeof(old_ctx.u.perf_counter.name));
 318                 }
 319                 return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_OLD_CONTEXT, &old_ctx);
 320         }
 321         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_CONTEXT, ctx);
 322 }
 323
 324
 325 /* Enable event, channel and session LTTNG_IOCTL_CHECK */
 326 int kernctl_enable(int fd)
 327 {
 328         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_ENABLE,
 329                         LTTNG_KERNEL_ENABLE);
 330 }
 331
 332 /* Disable event, channel and session LTTNG_IOCTL_CHECK */
 333 int kernctl_disable(int fd)
 334 {
 335         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_DISABLE,
 336                         LTTNG_KERNEL_DISABLE);
 337 }
 338
 339 int kernctl_start_session(int fd)
 340 {
 341         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION_START,
 342                         LTTNG_KERNEL_SESSION_START);
 343 }
 344
 345 int kernctl_stop_session(int fd)
 346 {
 347         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_SESSION_STOP,
 348                         LTTNG_KERNEL_SESSION_STOP);
 349 }
 350
 351 int kernctl_filter(int fd, struct lttng_filter_bytecode *filter)
 352 {
 353         struct lttng_kernel_filter_bytecode *kb;
 354         uint32_t len;
 355         int ret;
 356
 357         /* Translate bytecode to kernel bytecode */
 358         kb = zmalloc(sizeof(*kb) + filter->len);
 359         if (!kb)
 360                 return -ENOMEM;
 361         kb->len = len = filter->len;
 362         kb->reloc_offset = filter->reloc_table_offset;
 363         kb->seqnum = filter->seqnum;
 364         memcpy(kb->data, filter->data, len);
 365         ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_FILTER, kb);
 366         free(kb);
 367         return ret;
 368 }
 369
 370 int kernctl_add_callsite(int fd, struct lttng_kernel_event_callsite *callsite)
 371 {
 372         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_ADD_CALLSITE, callsite);
 373 }
 374
 375 int kernctl_tracepoint_list(int fd)
 376 {
 377         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_TRACEPOINT_LIST,
 378                         LTTNG_KERNEL_TRACEPOINT_LIST);
 379 }
 380
 381 int kernctl_syscall_list(int fd)
 382 {
 383         return LTTNG_IOCTL_NO_CHECK(fd, LTTNG_KERNEL_SYSCALL_LIST);
 384 }
 385
 386 int kernctl_tracer_version(int fd, struct lttng_kernel_tracer_version *v)
 387 {
 388         int ret;
 389
 390         if (lttng_kernel_use_old_abi == -1) {
 391                 ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_VERSION, v);
 392                 if (!ret) {
 393                         lttng_kernel_use_old_abi = 0;
 394                         goto end;
 395                 }
 396                 lttng_kernel_use_old_abi = 1;
 397         }
 398         if (lttng_kernel_use_old_abi) {
 399                 struct lttng_kernel_old_tracer_version old_v;
 400
 401                 ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_OLD_TRACER_VERSION, &old_v);
 402                 if (ret) {
 403                         goto end;
 404                 }
 405                 v->major = old_v.major;
 406                 v->minor = old_v.minor;
 407                 v->patchlevel = old_v.patchlevel;
 408         } else {
 409                 ret = LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_VERSION, v);
 410         }
 411
 412 end:
 413         return ret;
 414 }
 415
 416 int kernctl_tracer_abi_version(int fd,
 417                 struct lttng_kernel_tracer_abi_version *v)
 418 {
 419         return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_TRACER_ABI_VERSION, v);
 420 }
 421
 422 int kernctl_wait_quiescent(int fd)
 423 {
 424         return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_WAIT_QUIESCENT,
 425                         LTTNG_KERNEL_WAIT_QUIESCENT);
 426 }
 427
 428 int kernctl_buffer_flush(int fd)
 429 {
 430         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_FLUSH);
 431 }
 432
 433 int kernctl_buffer_flush_empty(int fd)
 434 {
 435         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_FLUSH_EMPTY);
 436 }
 437
 438 /* returns the version of the metadata. */
 439 int kernctl_get_metadata_version(int fd, uint64_t *version)
 440 {
 441         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_METADATA_VERSION, version);
 442 }
 443
 444 int kernctl_metadata_cache_dump(int fd)
 445 {
 446         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_METADATA_CACHE_DUMP);
 447 }
 448
 449 /* Buffer operations */
 450
 451 /* For mmap mode, readable without "get" operation */
 452
 453 /* returns the length to mmap. */
 454 int kernctl_get_mmap_len(int fd, unsigned long *len)
 455 {
 456         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MMAP_LEN, len);
 457 }
 458
 459 /* returns the maximum size for sub-buffers. */
 460 int kernctl_get_max_subbuf_size(int fd, unsigned long *len)
 461 {
 462         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MAX_SUBBUF_SIZE, len);
 463 }
 464
 465 /*
 466  * For mmap mode, operate on the current packet (between get/put or
 467  * get_next/put_next).
 468  */
 469
 470 /* returns the offset of the subbuffer belonging to the mmap reader. */
 471 int kernctl_get_mmap_read_offset(int fd, unsigned long *off)
 472 {
 473         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_MMAP_READ_OFFSET, off);
 474 }
 475
 476 /* returns the size of the current sub-buffer, without padding (for mmap). */
 477 int kernctl_get_subbuf_size(int fd, unsigned long *len)
 478 {
 479         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_SUBBUF_SIZE, len);
 480 }
 481
 482 /* returns the size of the current sub-buffer, without padding (for mmap). */
 483 int kernctl_get_padded_subbuf_size(int fd, unsigned long *len)
 484 {
 485         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_PADDED_SUBBUF_SIZE, len);
 486 }
 487
 488 /* Get exclusive read access to the next sub-buffer that can be read. */
 489 int kernctl_get_next_subbuf(int fd)
 490 {
 491         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_NEXT_SUBBUF);
 492 }
 493
 494
 495 /* Release exclusive sub-buffer access, move consumer forward. */
 496 int kernctl_put_next_subbuf(int fd)
 497 {
 498         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_PUT_NEXT_SUBBUF);
 499 }
 500
 501 /* snapshot */
 502
 503 /* Get a snapshot of the current ring buffer producer and consumer positions */
 504 int kernctl_snapshot(int fd)
 505 {
 506         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT);
 507 }
 508
 509 /*
 510  * Get a snapshot of the current ring buffer producer and consumer positions,
 511  * regardless of whether or not the two positions are contained within the
 512  * same sub-buffer.
 513  */
 514 int kernctl_snapshot_sample_positions(int fd)
 515 {
 516         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS);
 517 }
 518
 519 /* Get the consumer position (iteration start) */
 520 int kernctl_snapshot_get_consumed(int fd, unsigned long *pos)
 521 {
 522         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_GET_CONSUMED, pos);
 523 }
 524
 525 /* Get the producer position (iteration end) */
 526 int kernctl_snapshot_get_produced(int fd, unsigned long *pos)
 527 {
 528         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_SNAPSHOT_GET_PRODUCED, pos);
 529 }
 530
 531 /* Get exclusive read access to the specified sub-buffer position */
 532 int kernctl_get_subbuf(int fd, unsigned long *len)
 533 {
 534         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_GET_SUBBUF, len);
 535 }
 536
 537 /* Release exclusive sub-buffer access */
 538 int kernctl_put_subbuf(int fd)
 539 {
 540         return LTTNG_IOCTL_CHECK(fd, RING_BUFFER_PUT_SUBBUF);
 541 }
 542
 543 /* Returns the timestamp begin of the current sub-buffer. */
 544 int kernctl_get_timestamp_begin(int fd, uint64_t *timestamp_begin)
 545 {
 546         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN,
 547                         timestamp_begin);
 548 }
 549
 550 /* Returns the timestamp end of the current sub-buffer. */
 551 int kernctl_get_timestamp_end(int fd, uint64_t *timestamp_end)
 552 {
 553         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_TIMESTAMP_END,
 554                         timestamp_end);
 555 }
 556
 557 /* Returns the number of discarded events in the current sub-buffer. */
 558 int kernctl_get_events_discarded(int fd, uint64_t *events_discarded)
 559 {
 560         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED,
 561                         events_discarded);
 562 }
 563
 564 /* Returns the content size in the current sub-buffer. */
 565 int kernctl_get_content_size(int fd, uint64_t *content_size)
 566 {
 567         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_CONTENT_SIZE,
 568                         content_size);
 569 }
 570
 571 /* Returns the packet size in the current sub-buffer. */
 572 int kernctl_get_packet_size(int fd, uint64_t *packet_size)
 573 {
 574         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_PACKET_SIZE,
 575                         packet_size);
 576 }
 577
 578 /* Returns the stream id of the current sub-buffer. */
 579 int kernctl_get_stream_id(int fd, uint64_t *stream_id)
 580 {
 581         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_STREAM_ID,
 582                         stream_id);
 583 }
 584
 585 /* Returns the current timestamp. */
 586 int kernctl_get_current_timestamp(int fd, uint64_t *ts)
 587 {
 588         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP,
 589                         ts);
 590 }
 591
 592 /* Returns the packet sequence number of the current sub-buffer. */
 593 int kernctl_get_sequence_number(int fd, uint64_t *seq)
 594 {
 595         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_GET_SEQ_NUM, seq);
 596 }
 597
 598 /* Returns the stream instance id. */
 599 int kernctl_get_instance_id(int fd, uint64_t *id)
 600 {
 601         return LTTNG_IOCTL_CHECK(fd, LTTNG_RING_BUFFER_INSTANCE_ID, id);
 602 }