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