liblttng-ust-ctl/ustctl.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; only version 2
   8  * of the License.
   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
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18  */
  19
  20 #include <string.h>
  21 #include <lttng/ust-ctl.h>
  22 #include <lttng/ust-abi.h>
  23 #include <lttng/usterr-signal-safe.h>
  24 #include <lttng/ust-events.h>
  25 #include <sys/mman.h>
  26 #include <ust-comm.h>
  27
  28 #include "../libringbuffer/backend.h"
  29 #include "../libringbuffer/frontend.h"
  30
  31 volatile enum ust_loglevel ust_loglevel;
  32
  33 static
  34 void init_object(struct lttng_ust_object_data *data)
  35 {
  36         data->handle = -1;
  37         data->shm_fd = -1;
  38         data->wait_fd = -1;
  39         data->memory_map_size = 0;
  40 }
  41
  42 /*
  43  * If sock is negative, it means we don't have to notify the other side
  44  * (e.g. application has already vanished).
  45  */
  46 void ustctl_release_object(int sock, struct lttng_ust_object_data *data)
  47 {
  48         struct ustcomm_ust_msg lum;
  49         struct ustcomm_ust_reply lur;
  50         int ret;
  51
  52         if (data->shm_fd >= 0)
  53                 close(data->shm_fd);
  54         if (data->wait_fd >= 0)
  55                 close(data->wait_fd);
  56         if (sock >= 0) {
  57                 memset(&lum, 0, sizeof(lum));
  58                 lum.handle = data->handle;
  59                 lum.cmd = LTTNG_UST_RELEASE;
  60                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
  61                 assert(!ret);
  62         }
  63         free(data);
  64 }
  65
  66 /*
  67  * Send registration done packet to the application.
  68  */
  69 int ustctl_register_done(int sock)
  70 {
  71         struct ustcomm_ust_msg lum;
  72         struct ustcomm_ust_reply lur;
  73         int ret;
  74
  75         DBG("Sending register done command to %d", sock);
  76         memset(&lum, 0, sizeof(lum));
  77         lum.handle = LTTNG_UST_ROOT_HANDLE;
  78         lum.cmd = LTTNG_UST_REGISTER_DONE;
  79         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
  80         if (ret)
  81                 return ret;
  82         if (lur.ret_code != USTCOMM_OK) {
  83                 DBG("Return code: %s", ustcomm_get_readable_code(lur.ret_code));
  84                 goto error;
  85         }
  86         return 0;
  87
  88 error:
  89         return -1;
  90 }
  91
  92 /*
  93  * returns session handle.
  94  */
  95 int ustctl_create_session(int sock)
  96 {
  97         struct ustcomm_ust_msg lum;
  98         struct ustcomm_ust_reply lur;
  99         int ret, session_handle;
 100
 101         /* Create session */
 102         memset(&lum, 0, sizeof(lum));
 103         lum.handle = LTTNG_UST_ROOT_HANDLE;
 104         lum.cmd = LTTNG_UST_SESSION;
 105         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 106         if (ret)
 107                 return ret;
 108         session_handle = lur.ret_val;
 109         DBG("received session handle %u", session_handle);
 110         return session_handle;
 111 }
 112
 113 /* open the metadata global channel */
 114 int ustctl_open_metadata(int sock, int session_handle,
 115                 struct lttng_ust_channel_attr *chops,
 116                 struct lttng_ust_object_data **_metadata_data)
 117 {
 118         struct ustcomm_ust_msg lum;
 119         struct ustcomm_ust_reply lur;
 120         struct lttng_ust_object_data *metadata_data;
 121         int ret;
 122
 123         metadata_data = malloc(sizeof(*metadata_data));
 124         if (!metadata_data)
 125                 return -ENOMEM;
 126         init_object(metadata_data);
 127         /* Create metadata channel */
 128         memset(&lum, 0, sizeof(lum));
 129         lum.handle = session_handle;
 130         lum.cmd = LTTNG_UST_METADATA;
 131         lum.u.channel.overwrite = chops->overwrite;
 132         lum.u.channel.subbuf_size = chops->subbuf_size;
 133         lum.u.channel.num_subbuf = chops->num_subbuf;
 134         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 135         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 136         lum.u.channel.output = chops->output;
 137         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 138         if (ret) {
 139                 free(metadata_data);
 140                 return ret;
 141         }
 142         if (lur.ret_code != USTCOMM_OK) {
 143                 free(metadata_data);
 144                 return lur.ret_code;
 145         }
 146         metadata_data->handle = lur.ret_val;
 147         DBG("received metadata handle %u", metadata_data->handle);
 148         metadata_data->memory_map_size = lur.u.channel.memory_map_size;
 149         /* get shm fd */
 150         ret = ustcomm_recv_fd(sock);
 151         if (ret < 0)
 152                 goto error;
 153         metadata_data->shm_fd = ret;
 154         /* get wait fd */
 155         ret = ustcomm_recv_fd(sock);
 156         if (ret < 0)
 157                 goto error;
 158         metadata_data->wait_fd = ret;
 159         *_metadata_data = metadata_data;
 160         return 0;
 161
 162 error:
 163         ustctl_release_object(sock, metadata_data);
 164         return -EINVAL;
 165 }
 166
 167 int ustctl_create_channel(int sock, int session_handle,
 168                 struct lttng_ust_channel_attr *chops,
 169                 struct lttng_ust_object_data **_channel_data)
 170 {
 171         struct ustcomm_ust_msg lum;
 172         struct ustcomm_ust_reply lur;
 173         struct lttng_ust_object_data *channel_data;
 174         int ret;
 175
 176         channel_data = malloc(sizeof(*channel_data));
 177         if (!channel_data)
 178                 return -ENOMEM;
 179         init_object(channel_data);
 180         /* Create metadata channel */
 181         memset(&lum, 0, sizeof(lum));
 182         lum.handle = session_handle;
 183         lum.cmd = LTTNG_UST_CHANNEL;
 184         lum.u.channel.overwrite = chops->overwrite;
 185         lum.u.channel.subbuf_size = chops->subbuf_size;
 186         lum.u.channel.num_subbuf = chops->num_subbuf;
 187         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 188         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 189         lum.u.channel.output = chops->output;
 190         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 191         if (ret) {
 192                 free(channel_data);
 193                 return ret;
 194         }
 195         if (lur.ret_code != USTCOMM_OK) {
 196                 free(channel_data);
 197                 return lur.ret_code;
 198         }
 199         channel_data->handle = lur.ret_val;
 200         DBG("received channel handle %u", channel_data->handle);
 201         channel_data->memory_map_size = lur.u.channel.memory_map_size;
 202         /* get shm fd */
 203         ret = ustcomm_recv_fd(sock);
 204         if (ret < 0)
 205                 goto error;
 206         channel_data->shm_fd = ret;
 207         /* get wait fd */
 208         ret = ustcomm_recv_fd(sock);
 209         if (ret < 0)
 210                 goto error;
 211         channel_data->wait_fd = ret;
 212         *_channel_data = channel_data;
 213         return 0;
 214
 215 error:
 216         ustctl_release_object(sock, channel_data);
 217         return -EINVAL;
 218 }
 219
 220 /*
 221  * Return -ENOENT if no more stream is available for creation.
 222  * Return 0 on success.
 223  * Return negative error value on error.
 224  */
 225 int ustctl_create_stream(int sock, struct lttng_ust_object_data *channel_data,
 226                 struct lttng_ust_object_data **_stream_data)
 227 {
 228         struct ustcomm_ust_msg lum;
 229         struct ustcomm_ust_reply lur;
 230         struct lttng_ust_object_data *stream_data;
 231         int ret, fd;
 232
 233         stream_data = malloc(sizeof(*stream_data));
 234         if (!stream_data)
 235                 return -ENOMEM;
 236         init_object(stream_data);
 237         memset(&lum, 0, sizeof(lum));
 238         lum.handle = channel_data->handle;
 239         lum.cmd = LTTNG_UST_STREAM;
 240         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 241         if (ret) {
 242                 free(stream_data);
 243                 return ret;
 244         }
 245         if (lur.ret_code != USTCOMM_OK) {
 246                 free(stream_data);
 247                 return lur.ret_code;
 248         }
 249
 250         stream_data->handle = lur.ret_val;
 251         DBG("received stream handle %u", stream_data->handle);
 252         stream_data->memory_map_size = lur.u.stream.memory_map_size;
 253         /* get shm fd */
 254         fd = ustcomm_recv_fd(sock);
 255         if (fd < 0)
 256                 goto error;
 257         stream_data->shm_fd = fd;
 258         /* get wait fd */
 259         fd = ustcomm_recv_fd(sock);
 260         if (fd < 0)
 261                 goto error;
 262         stream_data->wait_fd = fd;
 263         *_stream_data = stream_data;
 264         return ret;
 265
 266 error:
 267         ustctl_release_object(sock, stream_data);
 268         return -EINVAL;
 269 }
 270
 271 int ustctl_create_event(int sock, struct lttng_ust_event *ev,
 272                 struct lttng_ust_object_data *channel_data,
 273                 struct lttng_ust_object_data **_event_data)
 274 {
 275         struct ustcomm_ust_msg lum;
 276         struct ustcomm_ust_reply lur;
 277         struct lttng_ust_object_data *event_data;
 278         int ret;
 279
 280         event_data = malloc(sizeof(*event_data));
 281         if (!event_data)
 282                 return -ENOMEM;
 283         init_object(event_data);
 284         memset(&lum, 0, sizeof(lum));
 285         lum.handle = channel_data->handle;
 286         lum.cmd = LTTNG_UST_EVENT;
 287         strncpy(lum.u.event.name, ev->name,
 288                 LTTNG_UST_SYM_NAME_LEN);
 289         lum.u.event.instrumentation = ev->instrumentation;
 290         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 291         if (ret) {
 292                 free(event_data);
 293                 return ret;
 294         }
 295         event_data->handle = lur.ret_val;
 296         DBG("received event handle %u", event_data->handle);
 297         *_event_data = event_data;
 298         return 0;
 299 }
 300
 301 int ustctl_add_context(int sock, struct lttng_ust_context *ctx,
 302                 struct lttng_ust_object_data *obj_data,
 303                 struct lttng_ust_object_data **_context_data)
 304 {
 305         struct ustcomm_ust_msg lum;
 306         struct ustcomm_ust_reply lur;
 307         struct lttng_ust_object_data *context_data;
 308         int ret;
 309
 310         context_data = malloc(sizeof(*context_data));
 311         if (!context_data)
 312                 return -ENOMEM;
 313         init_object(context_data);
 314         memset(&lum, 0, sizeof(lum));
 315         lum.handle = obj_data->handle;
 316         lum.cmd = LTTNG_UST_CONTEXT;
 317         lum.u.context.ctx = ctx->ctx;
 318         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 319         if (ret) {
 320                 free(context_data);
 321                 return ret;
 322         }
 323         context_data->handle = lur.ret_val;
 324         DBG("received context handle %u", context_data->handle);
 325         *_context_data = context_data;
 326         return ret;
 327 }
 328
 329 /* Enable event, channel and session ioctl */
 330 int ustctl_enable(int sock, struct lttng_ust_object_data *object)
 331 {
 332         struct ustcomm_ust_msg lum;
 333         struct ustcomm_ust_reply lur;
 334         int ret;
 335
 336         memset(&lum, 0, sizeof(lum));
 337         lum.handle = object->handle;
 338         lum.cmd = LTTNG_UST_ENABLE;
 339         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 340         if (ret)
 341                 return ret;
 342         DBG("enabled handle %u", object->handle);
 343         return 0;
 344 }
 345
 346 /* Disable event, channel and session ioctl */
 347 int ustctl_disable(int sock, struct lttng_ust_object_data *object)
 348 {
 349         struct ustcomm_ust_msg lum;
 350         struct ustcomm_ust_reply lur;
 351         int ret;
 352
 353         memset(&lum, 0, sizeof(lum));
 354         lum.handle = object->handle;
 355         lum.cmd = LTTNG_UST_DISABLE;
 356         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 357         if (ret)
 358                 return ret;
 359         DBG("disable handle %u", object->handle);
 360         return 0;
 361 }
 362
 363 int ustctl_start_session(int sock, int handle)
 364 {
 365         struct lttng_ust_object_data obj;
 366
 367         obj.handle = handle;
 368         return ustctl_enable(sock, &obj);
 369 }
 370
 371 int ustctl_stop_session(int sock, int handle)
 372 {
 373         struct lttng_ust_object_data obj;
 374
 375         obj.handle = handle;
 376         return ustctl_disable(sock, &obj);
 377 }
 378
 379 int ustctl_tracepoint_list(int sock)
 380 {
 381         struct ustcomm_ust_msg lum;
 382         struct ustcomm_ust_reply lur;
 383         int ret, tp_list_handle;
 384
 385         memset(&lum, 0, sizeof(lum));
 386         lum.handle = LTTNG_UST_ROOT_HANDLE;
 387         lum.cmd = LTTNG_UST_TRACEPOINT_LIST;
 388         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 389         if (ret)
 390                 return ret;
 391         tp_list_handle = lur.ret_val;
 392         DBG("received tracepoint list handle %u", tp_list_handle);
 393         return tp_list_handle;
 394 }
 395
 396 int ustctl_tracepoint_list_get(int sock, int tp_list_handle,
 397                 char iter[LTTNG_UST_SYM_NAME_LEN])
 398 {
 399         struct ustcomm_ust_msg lum;
 400         struct ustcomm_ust_reply lur;
 401         int ret;
 402
 403         memset(&lum, 0, sizeof(lum));
 404         lum.handle = tp_list_handle;
 405         lum.cmd = LTTNG_UST_TRACEPOINT_LIST_GET;
 406         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 407         if (ret)
 408                 return ret;
 409         DBG("received tracepoint list entry %s", lur.u.tracepoint_list_entry);
 410         memcpy(iter, lur.u.tracepoint_list_entry, LTTNG_UST_SYM_NAME_LEN);
 411         return 0;
 412 }
 413
 414 int ustctl_tracer_version(int sock, struct lttng_ust_tracer_version *v)
 415 {
 416         struct ustcomm_ust_msg lum;
 417         struct ustcomm_ust_reply lur;
 418         int ret;
 419
 420         memset(&lum, 0, sizeof(lum));
 421         lum.handle = LTTNG_UST_ROOT_HANDLE;
 422         lum.cmd = LTTNG_UST_TRACER_VERSION;
 423         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 424         if (ret)
 425                 return ret;
 426         memcpy(v, &lur.u.version, sizeof(*v));
 427         DBG("received tracer version");
 428         return 0;
 429 }
 430
 431 int ustctl_wait_quiescent(int sock)
 432 {
 433         struct ustcomm_ust_msg lum;
 434         struct ustcomm_ust_reply lur;
 435         int ret;
 436
 437         memset(&lum, 0, sizeof(lum));
 438         lum.handle = LTTNG_UST_ROOT_HANDLE;
 439         lum.cmd = LTTNG_UST_WAIT_QUIESCENT;
 440         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 441         if (ret)
 442                 return ret;
 443         DBG("waited for quiescent state");
 444         return 0;
 445 }
 446
 447 int ustctl_calibrate(int sock, struct lttng_ust_calibrate *calibrate)
 448 {
 449         return -ENOSYS;
 450 }
 451
 452 /* Buffer operations */
 453
 454 /* Map channel shm into process memory */
 455 struct lttng_ust_shm_handle *ustctl_map_channel(struct lttng_ust_object_data *chan_data)
 456 {
 457         struct lttng_ust_shm_handle *handle;
 458         struct channel *chan;
 459         size_t chan_size;
 460         struct lttng_ust_lib_ring_buffer_config *config;
 461         int ret;
 462
 463         handle = channel_handle_create(chan_data->shm_fd,
 464                 chan_data->wait_fd,
 465                 chan_data->memory_map_size);
 466         if (!handle) {
 467                 ERR("create handle error");
 468                 return NULL;
 469         }
 470         /*
 471          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 472          * of closing shm_fd and wait_fd.
 473          */
 474         chan_data->shm_fd = -1;
 475         chan_data->wait_fd = -1;
 476
 477         /*
 478          * TODO: add consistency checks to be resilient if the
 479          * application try to feed us with incoherent channel structure
 480          * values.
 481          */
 482         chan = shmp(handle, handle->chan);
 483         /* chan is object 0. This is hardcoded. */
 484         chan_size = handle->table->objects[0].allocated_len;
 485         handle->shadow_chan = malloc(chan_size);
 486         if (!handle->shadow_chan) {
 487                 channel_destroy(chan, handle, 1);
 488                 return NULL;
 489         }
 490         memcpy(handle->shadow_chan, chan, chan_size);
 491         /*
 492          * The callback pointers in the producer are invalid in the
 493          * consumer. We need to look them up here.
 494          */
 495         config = &handle->shadow_chan->backend.config;
 496         switch (config->client_type) {
 497         case LTTNG_CLIENT_METADATA:
 498                 memcpy(&config->cb, lttng_client_callbacks_metadata,
 499                         sizeof(config->cb));
 500                 break;
 501         case LTTNG_CLIENT_DISCARD:
 502                 memcpy(&config->cb, lttng_client_callbacks_discard,
 503                         sizeof(config->cb));
 504                 break;
 505         case LTTNG_CLIENT_OVERWRITE:
 506                 memcpy(&config->cb, lttng_client_callbacks_overwrite,
 507                         sizeof(config->cb));
 508                 break;
 509         default:
 510                 ERR("Unknown client type %d", config->client_type);
 511                 channel_destroy(chan, handle, 1);
 512                 return NULL;
 513         }
 514         /* Replace the object table pointer. */
 515         ret = munmap(handle->table->objects[0].memory_map,
 516                 handle->table->objects[0].memory_map_size);
 517         if (ret) {
 518                 perror("munmap");
 519                 assert(0);
 520         }
 521         handle->table->objects[0].memory_map = (char *) handle->shadow_chan;
 522         handle->table->objects[0].is_shadow = 1;
 523         return handle;
 524 }
 525
 526 /* Add stream to channel shm and map its shm into process memory */
 527 int ustctl_add_stream(struct lttng_ust_shm_handle *handle,
 528                 struct lttng_ust_object_data *stream_data)
 529 {
 530         int ret;
 531
 532         if (!stream_data->handle)
 533                 return -ENOENT;
 534         /* map stream */
 535         ret = channel_handle_add_stream(handle,
 536                 stream_data->shm_fd,
 537                 stream_data->wait_fd,
 538                 stream_data->memory_map_size);
 539         if (ret) {
 540                 ERR("add stream error\n");
 541                 return ret;
 542         }
 543         /*
 544          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 545          * of closing shm_fd and wait_fd.
 546          */
 547         stream_data->shm_fd = -1;
 548         stream_data->wait_fd = -1;
 549         return 0;
 550 }
 551
 552 void ustctl_unmap_channel(struct lttng_ust_shm_handle *handle)
 553 {
 554         struct channel *chan;
 555
 556         chan = shmp(handle, handle->chan);
 557         channel_destroy(chan, handle, 1);
 558 }
 559
 560 struct lttng_ust_lib_ring_buffer *ustctl_open_stream_read(struct lttng_ust_shm_handle *handle,
 561         int cpu)
 562 {
 563         struct channel *chan = handle->shadow_chan;
 564         int shm_fd, wait_fd;
 565         uint64_t memory_map_size;
 566         struct lttng_ust_lib_ring_buffer *buf;
 567         int ret;
 568
 569         buf = channel_get_ring_buffer(&chan->backend.config,
 570                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 571         if (!buf)
 572                 return NULL;
 573         ret = lib_ring_buffer_open_read(buf, handle, 1);
 574         if (ret)
 575                 return NULL;
 576         return buf;
 577 }
 578
 579 void ustctl_close_stream_read(struct lttng_ust_shm_handle *handle,
 580                 struct lttng_ust_lib_ring_buffer *buf)
 581 {
 582         lib_ring_buffer_release_read(buf, handle, 1);
 583 }
 584
 585 /* For mmap mode, readable without "get" operation */
 586
 587 void *ustctl_get_mmap_base(struct lttng_ust_shm_handle *handle,
 588                 struct lttng_ust_lib_ring_buffer *buf)
 589 {
 590         return shmp(handle, buf->backend.memory_map);
 591 }
 592
 593 /* returns the length to mmap. */
 594 int ustctl_get_mmap_len(struct lttng_ust_shm_handle *handle,
 595                 struct lttng_ust_lib_ring_buffer *buf,
 596                 unsigned long *len)
 597 {
 598         unsigned long mmap_buf_len;
 599         struct channel *chan = handle->shadow_chan;
 600
 601         if (chan->backend.config.output != RING_BUFFER_MMAP)
 602                 return -EINVAL;
 603         mmap_buf_len = chan->backend.buf_size;
 604         if (chan->backend.extra_reader_sb)
 605                 mmap_buf_len += chan->backend.subbuf_size;
 606         if (mmap_buf_len > INT_MAX)
 607                 return -EFBIG;
 608         *len = mmap_buf_len;
 609         return 0;
 610 }
 611
 612 /* returns the maximum size for sub-buffers. */
 613 int ustctl_get_max_subbuf_size(struct lttng_ust_shm_handle *handle,
 614                 struct lttng_ust_lib_ring_buffer *buf,
 615                 unsigned long *len)
 616 {
 617         struct channel *chan = handle->shadow_chan;
 618
 619         *len = chan->backend.subbuf_size;
 620         return 0;
 621 }
 622
 623 /*
 624  * For mmap mode, operate on the current packet (between get/put or
 625  * get_next/put_next).
 626  */
 627
 628 /* returns the offset of the subbuffer belonging to the mmap reader. */
 629 int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
 630                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 631 {
 632         struct channel *chan = handle->shadow_chan;
 633         unsigned long sb_bindex;
 634
 635         if (chan->backend.config.output != RING_BUFFER_MMAP)
 636                 return -EINVAL;
 637         sb_bindex = subbuffer_id_get_index(&chan->backend.config,
 638                                            buf->backend.buf_rsb.id);
 639         *off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
 640         return 0;
 641 }
 642
 643 /* returns the size of the current sub-buffer, without padding (for mmap). */
 644 int ustctl_get_subbuf_size(struct lttng_ust_shm_handle *handle,
 645                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 646 {
 647         struct channel *chan = handle->shadow_chan;
 648
 649         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 650                 handle);
 651         return 0;
 652 }
 653
 654 /* returns the size of the current sub-buffer, without padding (for mmap). */
 655 int ustctl_get_padded_subbuf_size(struct lttng_ust_shm_handle *handle,
 656                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 657 {
 658         struct channel *chan = handle->shadow_chan;
 659
 660         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 661                 handle);
 662         *len = PAGE_ALIGN(*len);
 663         return 0;
 664 }
 665
 666 /* Get exclusive read access to the next sub-buffer that can be read. */
 667 int ustctl_get_next_subbuf(struct lttng_ust_shm_handle *handle,
 668                 struct lttng_ust_lib_ring_buffer *buf)
 669 {
 670         return lib_ring_buffer_get_next_subbuf(buf, handle);
 671 }
 672
 673
 674 /* Release exclusive sub-buffer access, move consumer forward. */
 675 int ustctl_put_next_subbuf(struct lttng_ust_shm_handle *handle,
 676                 struct lttng_ust_lib_ring_buffer *buf)
 677 {
 678         lib_ring_buffer_put_next_subbuf(buf, handle);
 679         return 0;
 680 }
 681
 682 /* snapshot */
 683
 684 /* Get a snapshot of the current ring buffer producer and consumer positions */
 685 int ustctl_snapshot(struct lttng_ust_shm_handle *handle,
 686                 struct lttng_ust_lib_ring_buffer *buf)
 687 {
 688         return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 689                         &buf->prod_snapshot, handle);
 690 }
 691
 692 /* Get the consumer position (iteration start) */
 693 int ustctl_snapshot_get_consumed(struct lttng_ust_shm_handle *handle,
 694                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 695 {
 696         *pos = buf->cons_snapshot;
 697         return 0;
 698 }
 699
 700 /* Get the producer position (iteration end) */
 701 int ustctl_snapshot_get_produced(struct lttng_ust_shm_handle *handle,
 702                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 703 {
 704         *pos = buf->prod_snapshot;
 705         return 0;
 706 }
 707
 708 /* Get exclusive read access to the specified sub-buffer position */
 709 int ustctl_get_subbuf(struct lttng_ust_shm_handle *handle,
 710                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 711 {
 712         return lib_ring_buffer_get_subbuf(buf, *pos, handle);
 713 }
 714
 715 /* Release exclusive sub-buffer access */
 716 int ustctl_put_subbuf(struct lttng_ust_shm_handle *handle,
 717                 struct lttng_ust_lib_ring_buffer *buf)
 718 {
 719         lib_ring_buffer_put_subbuf(buf, handle);
 720         return 0;
 721 }
 722
 723 void ustctl_flush_buffer(struct lttng_ust_shm_handle *handle,
 724                 struct lttng_ust_lib_ring_buffer *buf,
 725                 int producer_active)
 726 {
 727         lib_ring_buffer_switch_slow(buf,
 728                 producer_active ? SWITCH_ACTIVE : SWITCH_FLUSH,
 729                 handle);
 730 }