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/ust-events.h>
  24 #include <sys/mman.h>
  25
  26 #include <usterr-signal-safe.h>
  27 #include <ust-comm.h>
  28
  29 #include "../libringbuffer/backend.h"
  30 #include "../libringbuffer/frontend.h"
  31
  32 volatile enum ust_loglevel ust_loglevel;
  33
  34 static
  35 void init_object(struct lttng_ust_object_data *data)
  36 {
  37         data->handle = -1;
  38         data->shm_fd = -1;
  39         data->wait_fd = -1;
  40         data->memory_map_size = 0;
  41 }
  42
  43 /*
  44  * If sock is negative, it means we don't have to notify the other side
  45  * (e.g. application has already vanished).
  46  */
  47 void ustctl_release_object(int sock, struct lttng_ust_object_data *data)
  48 {
  49         struct ustcomm_ust_msg lum;
  50         struct ustcomm_ust_reply lur;
  51         int ret;
  52
  53         if (data->shm_fd >= 0)
  54                 close(data->shm_fd);
  55         if (data->wait_fd >= 0)
  56                 close(data->wait_fd);
  57         if (sock >= 0) {
  58                 memset(&lum, 0, sizeof(lum));
  59                 lum.handle = data->handle;
  60                 lum.cmd = LTTNG_UST_RELEASE;
  61                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
  62                 assert(!ret);
  63         }
  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         free(metadata_data);
 165         return -EINVAL;
 166 }
 167
 168 int ustctl_create_channel(int sock, int session_handle,
 169                 struct lttng_ust_channel_attr *chops,
 170                 struct lttng_ust_object_data **_channel_data)
 171 {
 172         struct ustcomm_ust_msg lum;
 173         struct ustcomm_ust_reply lur;
 174         struct lttng_ust_object_data *channel_data;
 175         int ret;
 176
 177         channel_data = malloc(sizeof(*channel_data));
 178         if (!channel_data)
 179                 return -ENOMEM;
 180         init_object(channel_data);
 181         /* Create metadata channel */
 182         memset(&lum, 0, sizeof(lum));
 183         lum.handle = session_handle;
 184         lum.cmd = LTTNG_UST_CHANNEL;
 185         lum.u.channel.overwrite = chops->overwrite;
 186         lum.u.channel.subbuf_size = chops->subbuf_size;
 187         lum.u.channel.num_subbuf = chops->num_subbuf;
 188         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 189         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 190         lum.u.channel.output = chops->output;
 191         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 192         if (ret) {
 193                 free(channel_data);
 194                 return ret;
 195         }
 196         if (lur.ret_code != USTCOMM_OK) {
 197                 free(channel_data);
 198                 return lur.ret_code;
 199         }
 200         channel_data->handle = lur.ret_val;
 201         DBG("received channel handle %u", channel_data->handle);
 202         channel_data->memory_map_size = lur.u.channel.memory_map_size;
 203         /* get shm fd */
 204         ret = ustcomm_recv_fd(sock);
 205         if (ret < 0)
 206                 goto error;
 207         channel_data->shm_fd = ret;
 208         /* get wait fd */
 209         ret = ustcomm_recv_fd(sock);
 210         if (ret < 0)
 211                 goto error;
 212         channel_data->wait_fd = ret;
 213         *_channel_data = channel_data;
 214         return 0;
 215
 216 error:
 217         ustctl_release_object(sock, channel_data);
 218         free(channel_data);
 219         return -EINVAL;
 220 }
 221
 222 /*
 223  * Return -ENOENT if no more stream is available for creation.
 224  * Return 0 on success.
 225  * Return negative error value on error.
 226  */
 227 int ustctl_create_stream(int sock, struct lttng_ust_object_data *channel_data,
 228                 struct lttng_ust_object_data **_stream_data)
 229 {
 230         struct ustcomm_ust_msg lum;
 231         struct ustcomm_ust_reply lur;
 232         struct lttng_ust_object_data *stream_data;
 233         int ret, fd;
 234
 235         stream_data = malloc(sizeof(*stream_data));
 236         if (!stream_data)
 237                 return -ENOMEM;
 238         init_object(stream_data);
 239         memset(&lum, 0, sizeof(lum));
 240         lum.handle = channel_data->handle;
 241         lum.cmd = LTTNG_UST_STREAM;
 242         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 243         if (ret) {
 244                 free(stream_data);
 245                 return ret;
 246         }
 247         if (lur.ret_code != USTCOMM_OK) {
 248                 free(stream_data);
 249                 return lur.ret_code;
 250         }
 251
 252         stream_data->handle = lur.ret_val;
 253         DBG("received stream handle %u", stream_data->handle);
 254         stream_data->memory_map_size = lur.u.stream.memory_map_size;
 255         /* get shm fd */
 256         fd = ustcomm_recv_fd(sock);
 257         if (fd < 0)
 258                 goto error;
 259         stream_data->shm_fd = fd;
 260         /* get wait fd */
 261         fd = ustcomm_recv_fd(sock);
 262         if (fd < 0)
 263                 goto error;
 264         stream_data->wait_fd = fd;
 265         *_stream_data = stream_data;
 266         return ret;
 267
 268 error:
 269         ustctl_release_object(sock, stream_data);
 270         free(stream_data);
 271         return -EINVAL;
 272 }
 273
 274 int ustctl_create_event(int sock, struct lttng_ust_event *ev,
 275                 struct lttng_ust_object_data *channel_data,
 276                 struct lttng_ust_object_data **_event_data)
 277 {
 278         struct ustcomm_ust_msg lum;
 279         struct ustcomm_ust_reply lur;
 280         struct lttng_ust_object_data *event_data;
 281         int ret;
 282
 283         event_data = malloc(sizeof(*event_data));
 284         if (!event_data)
 285                 return -ENOMEM;
 286         init_object(event_data);
 287         memset(&lum, 0, sizeof(lum));
 288         lum.handle = channel_data->handle;
 289         lum.cmd = LTTNG_UST_EVENT;
 290         strncpy(lum.u.event.name, ev->name,
 291                 LTTNG_UST_SYM_NAME_LEN);
 292         lum.u.event.instrumentation = ev->instrumentation;
 293         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 294         if (ret) {
 295                 free(event_data);
 296                 return ret;
 297         }
 298         event_data->handle = lur.ret_val;
 299         DBG("received event handle %u", event_data->handle);
 300         *_event_data = event_data;
 301         return 0;
 302 }
 303
 304 int ustctl_add_context(int sock, struct lttng_ust_context *ctx,
 305                 struct lttng_ust_object_data *obj_data,
 306                 struct lttng_ust_object_data **_context_data)
 307 {
 308         struct ustcomm_ust_msg lum;
 309         struct ustcomm_ust_reply lur;
 310         struct lttng_ust_object_data *context_data;
 311         int ret;
 312
 313         context_data = malloc(sizeof(*context_data));
 314         if (!context_data)
 315                 return -ENOMEM;
 316         init_object(context_data);
 317         memset(&lum, 0, sizeof(lum));
 318         lum.handle = obj_data->handle;
 319         lum.cmd = LTTNG_UST_CONTEXT;
 320         lum.u.context.ctx = ctx->ctx;
 321         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 322         if (ret) {
 323                 free(context_data);
 324                 return ret;
 325         }
 326         context_data->handle = lur.ret_val;
 327         DBG("received context handle %u", context_data->handle);
 328         *_context_data = context_data;
 329         return ret;
 330 }
 331
 332 /* Enable event, channel and session ioctl */
 333 int ustctl_enable(int sock, struct lttng_ust_object_data *object)
 334 {
 335         struct ustcomm_ust_msg lum;
 336         struct ustcomm_ust_reply lur;
 337         int ret;
 338
 339         memset(&lum, 0, sizeof(lum));
 340         lum.handle = object->handle;
 341         lum.cmd = LTTNG_UST_ENABLE;
 342         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 343         if (ret)
 344                 return ret;
 345         DBG("enabled handle %u", object->handle);
 346         return 0;
 347 }
 348
 349 /* Disable event, channel and session ioctl */
 350 int ustctl_disable(int sock, struct lttng_ust_object_data *object)
 351 {
 352         struct ustcomm_ust_msg lum;
 353         struct ustcomm_ust_reply lur;
 354         int ret;
 355
 356         memset(&lum, 0, sizeof(lum));
 357         lum.handle = object->handle;
 358         lum.cmd = LTTNG_UST_DISABLE;
 359         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 360         if (ret)
 361                 return ret;
 362         DBG("disable handle %u", object->handle);
 363         return 0;
 364 }
 365
 366 int ustctl_start_session(int sock, int handle)
 367 {
 368         struct lttng_ust_object_data obj;
 369
 370         obj.handle = handle;
 371         return ustctl_enable(sock, &obj);
 372 }
 373
 374 int ustctl_stop_session(int sock, int handle)
 375 {
 376         struct lttng_ust_object_data obj;
 377
 378         obj.handle = handle;
 379         return ustctl_disable(sock, &obj);
 380 }
 381
 382 int ustctl_tracepoint_list(int sock)
 383 {
 384         struct ustcomm_ust_msg lum;
 385         struct ustcomm_ust_reply lur;
 386         int ret, tp_list_handle;
 387
 388         memset(&lum, 0, sizeof(lum));
 389         lum.handle = LTTNG_UST_ROOT_HANDLE;
 390         lum.cmd = LTTNG_UST_TRACEPOINT_LIST;
 391         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 392         if (ret)
 393                 return ret;
 394         tp_list_handle = lur.ret_val;
 395         DBG("received tracepoint list handle %u", tp_list_handle);
 396         return tp_list_handle;
 397 }
 398
 399 int ustctl_tracepoint_list_get(int sock, int tp_list_handle,
 400                 char iter[LTTNG_UST_SYM_NAME_LEN])
 401 {
 402         struct ustcomm_ust_msg lum;
 403         struct ustcomm_ust_reply lur;
 404         int ret;
 405
 406         memset(&lum, 0, sizeof(lum));
 407         lum.handle = tp_list_handle;
 408         lum.cmd = LTTNG_UST_TRACEPOINT_LIST_GET;
 409         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 410         if (ret)
 411                 return ret;
 412         DBG("received tracepoint list entry %s", lur.u.tracepoint_list_entry);
 413         memcpy(iter, lur.u.tracepoint_list_entry, LTTNG_UST_SYM_NAME_LEN);
 414         return 0;
 415 }
 416
 417 int ustctl_tracer_version(int sock, struct lttng_ust_tracer_version *v)
 418 {
 419         struct ustcomm_ust_msg lum;
 420         struct ustcomm_ust_reply lur;
 421         int ret;
 422
 423         memset(&lum, 0, sizeof(lum));
 424         lum.handle = LTTNG_UST_ROOT_HANDLE;
 425         lum.cmd = LTTNG_UST_TRACER_VERSION;
 426         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 427         if (ret)
 428                 return ret;
 429         memcpy(v, &lur.u.version, sizeof(*v));
 430         DBG("received tracer version");
 431         return 0;
 432 }
 433
 434 int ustctl_wait_quiescent(int sock)
 435 {
 436         struct ustcomm_ust_msg lum;
 437         struct ustcomm_ust_reply lur;
 438         int ret;
 439
 440         memset(&lum, 0, sizeof(lum));
 441         lum.handle = LTTNG_UST_ROOT_HANDLE;
 442         lum.cmd = LTTNG_UST_WAIT_QUIESCENT;
 443         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 444         if (ret)
 445                 return ret;
 446         DBG("waited for quiescent state");
 447         return 0;
 448 }
 449
 450 int ustctl_calibrate(int sock, struct lttng_ust_calibrate *calibrate)
 451 {
 452         return -ENOSYS;
 453 }
 454
 455 /* Buffer operations */
 456
 457 /* Map channel shm into process memory */
 458 struct lttng_ust_shm_handle *ustctl_map_channel(struct lttng_ust_object_data *chan_data)
 459 {
 460         struct lttng_ust_shm_handle *handle;
 461         struct channel *chan;
 462         size_t chan_size;
 463         struct lttng_ust_lib_ring_buffer_config *config;
 464         int ret;
 465
 466         handle = channel_handle_create(chan_data->shm_fd,
 467                 chan_data->wait_fd,
 468                 chan_data->memory_map_size);
 469         if (!handle) {
 470                 ERR("create handle error");
 471                 return NULL;
 472         }
 473         /*
 474          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 475          * of closing shm_fd and wait_fd.
 476          */
 477         chan_data->shm_fd = -1;
 478         chan_data->wait_fd = -1;
 479
 480         /*
 481          * TODO: add consistency checks to be resilient if the
 482          * application try to feed us with incoherent channel structure
 483          * values.
 484          */
 485         chan = shmp(handle, handle->chan);
 486         /* chan is object 0. This is hardcoded. */
 487         chan_size = handle->table->objects[0].allocated_len;
 488         handle->shadow_chan = malloc(chan_size);
 489         if (!handle->shadow_chan) {
 490                 channel_destroy(chan, handle, 1);
 491                 return NULL;
 492         }
 493         memcpy(handle->shadow_chan, chan, chan_size);
 494         /*
 495          * The callback pointers in the producer are invalid in the
 496          * consumer. We need to look them up here.
 497          */
 498         config = &handle->shadow_chan->backend.config;
 499         switch (config->client_type) {
 500         case LTTNG_CLIENT_METADATA:
 501                 memcpy(&config->cb, lttng_client_callbacks_metadata,
 502                         sizeof(config->cb));
 503                 break;
 504         case LTTNG_CLIENT_DISCARD:
 505                 memcpy(&config->cb, lttng_client_callbacks_discard,
 506                         sizeof(config->cb));
 507                 break;
 508         case LTTNG_CLIENT_OVERWRITE:
 509                 memcpy(&config->cb, lttng_client_callbacks_overwrite,
 510                         sizeof(config->cb));
 511                 break;
 512         default:
 513                 ERR("Unknown client type %d", config->client_type);
 514                 channel_destroy(chan, handle, 1);
 515                 return NULL;
 516         }
 517         /* Replace the object table pointer. */
 518         ret = munmap(handle->table->objects[0].memory_map,
 519                 handle->table->objects[0].memory_map_size);
 520         if (ret) {
 521                 perror("munmap");
 522                 assert(0);
 523         }
 524         handle->table->objects[0].memory_map = (char *) handle->shadow_chan;
 525         handle->table->objects[0].is_shadow = 1;
 526         return handle;
 527 }
 528
 529 /* Add stream to channel shm and map its shm into process memory */
 530 int ustctl_add_stream(struct lttng_ust_shm_handle *handle,
 531                 struct lttng_ust_object_data *stream_data)
 532 {
 533         int ret;
 534
 535         if (!stream_data->handle)
 536                 return -ENOENT;
 537         /* map stream */
 538         ret = channel_handle_add_stream(handle,
 539                 stream_data->shm_fd,
 540                 stream_data->wait_fd,
 541                 stream_data->memory_map_size);
 542         if (ret) {
 543                 ERR("add stream error\n");
 544                 return ret;
 545         }
 546         /*
 547          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 548          * of closing shm_fd and wait_fd.
 549          */
 550         stream_data->shm_fd = -1;
 551         stream_data->wait_fd = -1;
 552         return 0;
 553 }
 554
 555 void ustctl_unmap_channel(struct lttng_ust_shm_handle *handle)
 556 {
 557         struct channel *chan;
 558
 559         chan = shmp(handle, handle->chan);
 560         channel_destroy(chan, handle, 1);
 561 }
 562
 563 struct lttng_ust_lib_ring_buffer *ustctl_open_stream_read(struct lttng_ust_shm_handle *handle,
 564         int cpu)
 565 {
 566         struct channel *chan = handle->shadow_chan;
 567         int shm_fd, wait_fd;
 568         uint64_t memory_map_size;
 569         struct lttng_ust_lib_ring_buffer *buf;
 570         int ret;
 571
 572         buf = channel_get_ring_buffer(&chan->backend.config,
 573                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 574         if (!buf)
 575                 return NULL;
 576         ret = lib_ring_buffer_open_read(buf, handle, 1);
 577         if (ret)
 578                 return NULL;
 579         return buf;
 580 }
 581
 582 void ustctl_close_stream_read(struct lttng_ust_shm_handle *handle,
 583                 struct lttng_ust_lib_ring_buffer *buf)
 584 {
 585         lib_ring_buffer_release_read(buf, handle, 1);
 586 }
 587
 588 /* For mmap mode, readable without "get" operation */
 589
 590 void *ustctl_get_mmap_base(struct lttng_ust_shm_handle *handle,
 591                 struct lttng_ust_lib_ring_buffer *buf)
 592 {
 593         return shmp(handle, buf->backend.memory_map);
 594 }
 595
 596 /* returns the length to mmap. */
 597 int ustctl_get_mmap_len(struct lttng_ust_shm_handle *handle,
 598                 struct lttng_ust_lib_ring_buffer *buf,
 599                 unsigned long *len)
 600 {
 601         unsigned long mmap_buf_len;
 602         struct channel *chan = handle->shadow_chan;
 603
 604         if (chan->backend.config.output != RING_BUFFER_MMAP)
 605                 return -EINVAL;
 606         mmap_buf_len = chan->backend.buf_size;
 607         if (chan->backend.extra_reader_sb)
 608                 mmap_buf_len += chan->backend.subbuf_size;
 609         if (mmap_buf_len > INT_MAX)
 610                 return -EFBIG;
 611         *len = mmap_buf_len;
 612         return 0;
 613 }
 614
 615 /* returns the maximum size for sub-buffers. */
 616 int ustctl_get_max_subbuf_size(struct lttng_ust_shm_handle *handle,
 617                 struct lttng_ust_lib_ring_buffer *buf,
 618                 unsigned long *len)
 619 {
 620         struct channel *chan = handle->shadow_chan;
 621
 622         *len = chan->backend.subbuf_size;
 623         return 0;
 624 }
 625
 626 /*
 627  * For mmap mode, operate on the current packet (between get/put or
 628  * get_next/put_next).
 629  */
 630
 631 /* returns the offset of the subbuffer belonging to the mmap reader. */
 632 int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
 633                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 634 {
 635         struct channel *chan = handle->shadow_chan;
 636         unsigned long sb_bindex;
 637
 638         if (chan->backend.config.output != RING_BUFFER_MMAP)
 639                 return -EINVAL;
 640         sb_bindex = subbuffer_id_get_index(&chan->backend.config,
 641                                            buf->backend.buf_rsb.id);
 642         *off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
 643         return 0;
 644 }
 645
 646 /* returns the size of the current sub-buffer, without padding (for mmap). */
 647 int ustctl_get_subbuf_size(struct lttng_ust_shm_handle *handle,
 648                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 649 {
 650         struct channel *chan = handle->shadow_chan;
 651
 652         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 653                 handle);
 654         return 0;
 655 }
 656
 657 /* returns the size of the current sub-buffer, without padding (for mmap). */
 658 int ustctl_get_padded_subbuf_size(struct lttng_ust_shm_handle *handle,
 659                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 660 {
 661         struct channel *chan = handle->shadow_chan;
 662
 663         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 664                 handle);
 665         *len = PAGE_ALIGN(*len);
 666         return 0;
 667 }
 668
 669 /* Get exclusive read access to the next sub-buffer that can be read. */
 670 int ustctl_get_next_subbuf(struct lttng_ust_shm_handle *handle,
 671                 struct lttng_ust_lib_ring_buffer *buf)
 672 {
 673         return lib_ring_buffer_get_next_subbuf(buf, handle);
 674 }
 675
 676
 677 /* Release exclusive sub-buffer access, move consumer forward. */
 678 int ustctl_put_next_subbuf(struct lttng_ust_shm_handle *handle,
 679                 struct lttng_ust_lib_ring_buffer *buf)
 680 {
 681         lib_ring_buffer_put_next_subbuf(buf, handle);
 682         return 0;
 683 }
 684
 685 /* snapshot */
 686
 687 /* Get a snapshot of the current ring buffer producer and consumer positions */
 688 int ustctl_snapshot(struct lttng_ust_shm_handle *handle,
 689                 struct lttng_ust_lib_ring_buffer *buf)
 690 {
 691         return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 692                         &buf->prod_snapshot, handle);
 693 }
 694
 695 /* Get the consumer position (iteration start) */
 696 int ustctl_snapshot_get_consumed(struct lttng_ust_shm_handle *handle,
 697                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 698 {
 699         *pos = buf->cons_snapshot;
 700         return 0;
 701 }
 702
 703 /* Get the producer position (iteration end) */
 704 int ustctl_snapshot_get_produced(struct lttng_ust_shm_handle *handle,
 705                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 706 {
 707         *pos = buf->prod_snapshot;
 708         return 0;
 709 }
 710
 711 /* Get exclusive read access to the specified sub-buffer position */
 712 int ustctl_get_subbuf(struct lttng_ust_shm_handle *handle,
 713                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 714 {
 715         return lib_ring_buffer_get_subbuf(buf, *pos, handle);
 716 }
 717
 718 /* Release exclusive sub-buffer access */
 719 int ustctl_put_subbuf(struct lttng_ust_shm_handle *handle,
 720                 struct lttng_ust_lib_ring_buffer *buf)
 721 {
 722         lib_ring_buffer_put_subbuf(buf, handle);
 723         return 0;
 724 }
 725
 726 void ustctl_flush_buffer(struct lttng_ust_shm_handle *handle,
 727                 struct lttng_ust_lib_ring_buffer *buf,
 728                 int producer_active)
 729 {
 730         lib_ring_buffer_switch_slow(buf,
 731                 producer_active ? SWITCH_ACTIVE : SWITCH_FLUSH,
 732                 handle);
 733 }