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 modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; version 2 of the License only.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  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 int ustctl_release_handle(int sock, int handle)
  44 {
  45         struct ustcomm_ust_msg lum;
  46         struct ustcomm_ust_reply lur;
  47         int ret;
  48
  49         if (sock >= 0) {
  50                 memset(&lum, 0, sizeof(lum));
  51                 lum.handle = handle;
  52                 lum.cmd = LTTNG_UST_RELEASE;
  53                 ret = ustcomm_send_app_cmd(sock, &lum, &lur);
  54                 if (ret < 0) {
  55                         return ret;
  56                 }
  57         }
  58         return 0;
  59 }
  60 /*
  61  * If sock is negative, it means we don't have to notify the other side
  62  * (e.g. application has already vanished).
  63  */
  64 int ustctl_release_object(int sock, struct lttng_ust_object_data *data)
  65 {
  66         int ret;
  67
  68         if (!data)
  69                 return -EINVAL;
  70
  71         if (data->shm_fd >= 0) {
  72                 ret = close(data->shm_fd);
  73                 if (ret < 0) {
  74                         return ret;
  75                 }
  76         }
  77         if (data->wait_fd >= 0) {
  78                 ret = close(data->wait_fd);
  79                 if (ret < 0) {
  80                         return ret;
  81                 }
  82         }
  83         return ustctl_release_handle(sock, data->handle);
  84 }
  85
  86 /*
  87  * Send registration done packet to the application.
  88  */
  89 int ustctl_register_done(int sock)
  90 {
  91         struct ustcomm_ust_msg lum;
  92         struct ustcomm_ust_reply lur;
  93         int ret;
  94
  95         DBG("Sending register done command to %d", sock);
  96         memset(&lum, 0, sizeof(lum));
  97         lum.handle = LTTNG_UST_ROOT_HANDLE;
  98         lum.cmd = LTTNG_UST_REGISTER_DONE;
  99         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 100         if (ret)
 101                 return ret;
 102         if (lur.ret_code != USTCOMM_OK) {
 103                 DBG("Return code: %s", ustcomm_get_readable_code(lur.ret_code));
 104                 goto error;
 105         }
 106         return 0;
 107
 108 error:
 109         return -1;
 110 }
 111
 112 /*
 113  * returns session handle.
 114  */
 115 int ustctl_create_session(int sock)
 116 {
 117         struct ustcomm_ust_msg lum;
 118         struct ustcomm_ust_reply lur;
 119         int ret, session_handle;
 120
 121         /* Create session */
 122         memset(&lum, 0, sizeof(lum));
 123         lum.handle = LTTNG_UST_ROOT_HANDLE;
 124         lum.cmd = LTTNG_UST_SESSION;
 125         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 126         if (ret)
 127                 return ret;
 128         session_handle = lur.ret_val;
 129         DBG("received session handle %u", session_handle);
 130         return session_handle;
 131 }
 132
 133 /* open the metadata global channel */
 134 int ustctl_open_metadata(int sock, int session_handle,
 135                 struct lttng_ust_channel_attr *chops,
 136                 struct lttng_ust_object_data **_metadata_data)
 137 {
 138         struct ustcomm_ust_msg lum;
 139         struct ustcomm_ust_reply lur;
 140         struct lttng_ust_object_data *metadata_data;
 141         int ret, err = 0;
 142
 143         if (!chops || !_metadata_data)
 144                 return -EINVAL;
 145
 146         metadata_data = malloc(sizeof(*metadata_data));
 147         if (!metadata_data)
 148                 return -ENOMEM;
 149         init_object(metadata_data);
 150         /* Create metadata channel */
 151         memset(&lum, 0, sizeof(lum));
 152         lum.handle = session_handle;
 153         lum.cmd = LTTNG_UST_METADATA;
 154         lum.u.channel.overwrite = chops->overwrite;
 155         lum.u.channel.subbuf_size = chops->subbuf_size;
 156         lum.u.channel.num_subbuf = chops->num_subbuf;
 157         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 158         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 159         lum.u.channel.output = chops->output;
 160         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 161         if (ret) {
 162                 free(metadata_data);
 163                 return ret;
 164         }
 165         if (lur.ret_code != USTCOMM_OK) {
 166                 free(metadata_data);
 167                 return lur.ret_code;
 168         }
 169         metadata_data->handle = lur.ret_val;
 170         DBG("received metadata handle %u", metadata_data->handle);
 171         metadata_data->memory_map_size = lur.u.channel.memory_map_size;
 172         /* get shm fd */
 173         ret = ustcomm_recv_fd(sock);
 174         if (ret < 0)
 175                 err = 1;
 176         else
 177                 metadata_data->shm_fd = ret;
 178         /*
 179          * We need to get the second FD even if the first fails, because
 180          * libust expects us to read the two FDs.
 181          */
 182         /* get wait fd */
 183         ret = ustcomm_recv_fd(sock);
 184         if (ret < 0)
 185                 err = 1;
 186         else
 187                 metadata_data->wait_fd = ret;
 188         if (err)
 189                 goto error;
 190         *_metadata_data = metadata_data;
 191         return 0;
 192
 193 error:
 194         (void) ustctl_release_object(sock, metadata_data);
 195         free(metadata_data);
 196         return -EINVAL;
 197 }
 198
 199 int ustctl_create_channel(int sock, int session_handle,
 200                 struct lttng_ust_channel_attr *chops,
 201                 struct lttng_ust_object_data **_channel_data)
 202 {
 203         struct ustcomm_ust_msg lum;
 204         struct ustcomm_ust_reply lur;
 205         struct lttng_ust_object_data *channel_data;
 206         int ret, err = 0;
 207
 208         if (!chops || !_channel_data)
 209                 return -EINVAL;
 210
 211         channel_data = malloc(sizeof(*channel_data));
 212         if (!channel_data)
 213                 return -ENOMEM;
 214         init_object(channel_data);
 215         /* Create metadata channel */
 216         memset(&lum, 0, sizeof(lum));
 217         lum.handle = session_handle;
 218         lum.cmd = LTTNG_UST_CHANNEL;
 219         lum.u.channel.overwrite = chops->overwrite;
 220         lum.u.channel.subbuf_size = chops->subbuf_size;
 221         lum.u.channel.num_subbuf = chops->num_subbuf;
 222         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 223         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 224         lum.u.channel.output = chops->output;
 225         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 226         if (ret) {
 227                 free(channel_data);
 228                 return ret;
 229         }
 230         if (lur.ret_code != USTCOMM_OK) {
 231                 free(channel_data);
 232                 return lur.ret_code;
 233         }
 234         channel_data->handle = lur.ret_val;
 235         DBG("received channel handle %u", channel_data->handle);
 236         channel_data->memory_map_size = lur.u.channel.memory_map_size;
 237         /* get shm fd */
 238         ret = ustcomm_recv_fd(sock);
 239         if (ret < 0)
 240                 err = 1;
 241         else
 242                 channel_data->shm_fd = ret;
 243         /*
 244          * We need to get the second FD even if the first fails, because
 245          * libust expects us to read the two FDs.
 246          */
 247         /* get wait fd */
 248         ret = ustcomm_recv_fd(sock);
 249         if (ret < 0)
 250                 err = 1;
 251         else
 252                 channel_data->wait_fd = ret;
 253         if (err)
 254                 goto error;
 255         *_channel_data = channel_data;
 256         return 0;
 257
 258 error:
 259         (void) ustctl_release_object(sock, channel_data);
 260         free(channel_data);
 261         return -EINVAL;
 262 }
 263
 264 /*
 265  * Return -ENOENT if no more stream is available for creation.
 266  * Return 0 on success.
 267  * Return negative error value on error.
 268  */
 269 int ustctl_create_stream(int sock, struct lttng_ust_object_data *channel_data,
 270                 struct lttng_ust_object_data **_stream_data)
 271 {
 272         struct ustcomm_ust_msg lum;
 273         struct ustcomm_ust_reply lur;
 274         struct lttng_ust_object_data *stream_data;
 275         int ret, fd, err = 0;
 276
 277         if (!channel_data || !_stream_data)
 278                 return -EINVAL;
 279
 280         stream_data = malloc(sizeof(*stream_data));
 281         if (!stream_data)
 282                 return -ENOMEM;
 283         init_object(stream_data);
 284         memset(&lum, 0, sizeof(lum));
 285         lum.handle = channel_data->handle;
 286         lum.cmd = LTTNG_UST_STREAM;
 287         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 288         if (ret) {
 289                 free(stream_data);
 290                 return ret;
 291         }
 292         if (lur.ret_code != USTCOMM_OK) {
 293                 free(stream_data);
 294                 return lur.ret_code;
 295         }
 296
 297         stream_data->handle = lur.ret_val;
 298         DBG("received stream handle %u", stream_data->handle);
 299         stream_data->memory_map_size = lur.u.stream.memory_map_size;
 300         /* get shm fd */
 301         fd = ustcomm_recv_fd(sock);
 302         if (fd < 0)
 303                 err = 1;
 304         else
 305                 stream_data->shm_fd = fd;
 306         /*
 307          * We need to get the second FD even if the first fails, because
 308          * libust expects us to read the two FDs.
 309          */
 310         /* get wait fd */
 311         fd = ustcomm_recv_fd(sock);
 312         if (fd < 0)
 313                 err = 1;
 314         else
 315                 stream_data->wait_fd = fd;
 316         if (err)
 317                 goto error;
 318         *_stream_data = stream_data;
 319         return ret;
 320
 321 error:
 322         (void) ustctl_release_object(sock, stream_data);
 323         free(stream_data);
 324         return -EINVAL;
 325 }
 326
 327 int ustctl_create_event(int sock, struct lttng_ust_event *ev,
 328                 struct lttng_ust_object_data *channel_data,
 329                 struct lttng_ust_object_data **_event_data)
 330 {
 331         struct ustcomm_ust_msg lum;
 332         struct ustcomm_ust_reply lur;
 333         struct lttng_ust_object_data *event_data;
 334         int ret;
 335
 336         if (!channel_data || !_event_data)
 337                 return -EINVAL;
 338
 339         event_data = malloc(sizeof(*event_data));
 340         if (!event_data)
 341                 return -ENOMEM;
 342         init_object(event_data);
 343         memset(&lum, 0, sizeof(lum));
 344         lum.handle = channel_data->handle;
 345         lum.cmd = LTTNG_UST_EVENT;
 346         strncpy(lum.u.event.name, ev->name,
 347                 LTTNG_UST_SYM_NAME_LEN);
 348         lum.u.event.instrumentation = ev->instrumentation;
 349         lum.u.event.loglevel_type = ev->loglevel_type;
 350         lum.u.event.loglevel = ev->loglevel;
 351         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 352         if (ret) {
 353                 free(event_data);
 354                 return ret;
 355         }
 356         event_data->handle = lur.ret_val;
 357         DBG("received event handle %u", event_data->handle);
 358         *_event_data = event_data;
 359         return 0;
 360 }
 361
 362 int ustctl_add_context(int sock, struct lttng_ust_context *ctx,
 363                 struct lttng_ust_object_data *obj_data,
 364                 struct lttng_ust_object_data **_context_data)
 365 {
 366         struct ustcomm_ust_msg lum;
 367         struct ustcomm_ust_reply lur;
 368         struct lttng_ust_object_data *context_data;
 369         int ret;
 370
 371         if (!obj_data || !_context_data)
 372                 return -EINVAL;
 373
 374         context_data = malloc(sizeof(*context_data));
 375         if (!context_data)
 376                 return -ENOMEM;
 377         init_object(context_data);
 378         memset(&lum, 0, sizeof(lum));
 379         lum.handle = obj_data->handle;
 380         lum.cmd = LTTNG_UST_CONTEXT;
 381         lum.u.context.ctx = ctx->ctx;
 382         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 383         if (ret) {
 384                 free(context_data);
 385                 return ret;
 386         }
 387         context_data->handle = lur.ret_val;
 388         DBG("received context handle %u", context_data->handle);
 389         *_context_data = context_data;
 390         return ret;
 391 }
 392
 393 /* Enable event, channel and session ioctl */
 394 int ustctl_enable(int sock, struct lttng_ust_object_data *object)
 395 {
 396         struct ustcomm_ust_msg lum;
 397         struct ustcomm_ust_reply lur;
 398         int ret;
 399
 400         if (!object)
 401                 return -EINVAL;
 402
 403         memset(&lum, 0, sizeof(lum));
 404         lum.handle = object->handle;
 405         lum.cmd = LTTNG_UST_ENABLE;
 406         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 407         if (ret)
 408                 return ret;
 409         DBG("enabled handle %u", object->handle);
 410         return 0;
 411 }
 412
 413 /* Disable event, channel and session ioctl */
 414 int ustctl_disable(int sock, struct lttng_ust_object_data *object)
 415 {
 416         struct ustcomm_ust_msg lum;
 417         struct ustcomm_ust_reply lur;
 418         int ret;
 419
 420         if (!object)
 421                 return -EINVAL;
 422
 423         memset(&lum, 0, sizeof(lum));
 424         lum.handle = object->handle;
 425         lum.cmd = LTTNG_UST_DISABLE;
 426         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 427         if (ret)
 428                 return ret;
 429         DBG("disable handle %u", object->handle);
 430         return 0;
 431 }
 432
 433 int ustctl_start_session(int sock, int handle)
 434 {
 435         struct lttng_ust_object_data obj;
 436
 437         obj.handle = handle;
 438         return ustctl_enable(sock, &obj);
 439 }
 440
 441 int ustctl_stop_session(int sock, int handle)
 442 {
 443         struct lttng_ust_object_data obj;
 444
 445         obj.handle = handle;
 446         return ustctl_disable(sock, &obj);
 447 }
 448
 449 int ustctl_tracepoint_list(int sock)
 450 {
 451         struct ustcomm_ust_msg lum;
 452         struct ustcomm_ust_reply lur;
 453         int ret, tp_list_handle;
 454
 455         memset(&lum, 0, sizeof(lum));
 456         lum.handle = LTTNG_UST_ROOT_HANDLE;
 457         lum.cmd = LTTNG_UST_TRACEPOINT_LIST;
 458         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 459         if (ret)
 460                 return ret;
 461         tp_list_handle = lur.ret_val;
 462         DBG("received tracepoint list handle %u", tp_list_handle);
 463         return tp_list_handle;
 464 }
 465
 466 int ustctl_tracepoint_list_get(int sock, int tp_list_handle,
 467                 struct lttng_ust_tracepoint_iter *iter)
 468 {
 469         struct ustcomm_ust_msg lum;
 470         struct ustcomm_ust_reply lur;
 471         int ret;
 472
 473         if (!iter)
 474                 return -EINVAL;
 475
 476         memset(&lum, 0, sizeof(lum));
 477         lum.handle = tp_list_handle;
 478         lum.cmd = LTTNG_UST_TRACEPOINT_LIST_GET;
 479         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 480         if (ret)
 481                 return ret;
 482         DBG("received tracepoint list entry name %s loglevel %d",
 483                 lur.u.tracepoint.name,
 484                 lur.u.tracepoint.loglevel);
 485         memcpy(iter, &lur.u.tracepoint, sizeof(*iter));
 486         return 0;
 487 }
 488
 489 int ustctl_tracer_version(int sock, struct lttng_ust_tracer_version *v)
 490 {
 491         struct ustcomm_ust_msg lum;
 492         struct ustcomm_ust_reply lur;
 493         int ret;
 494
 495         if (!v)
 496                 return -EINVAL;
 497
 498         memset(&lum, 0, sizeof(lum));
 499         lum.handle = LTTNG_UST_ROOT_HANDLE;
 500         lum.cmd = LTTNG_UST_TRACER_VERSION;
 501         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 502         if (ret)
 503                 return ret;
 504         memcpy(v, &lur.u.version, sizeof(*v));
 505         DBG("received tracer version");
 506         return 0;
 507 }
 508
 509 int ustctl_wait_quiescent(int sock)
 510 {
 511         struct ustcomm_ust_msg lum;
 512         struct ustcomm_ust_reply lur;
 513         int ret;
 514
 515         memset(&lum, 0, sizeof(lum));
 516         lum.handle = LTTNG_UST_ROOT_HANDLE;
 517         lum.cmd = LTTNG_UST_WAIT_QUIESCENT;
 518         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 519         if (ret)
 520                 return ret;
 521         DBG("waited for quiescent state");
 522         return 0;
 523 }
 524
 525 int ustctl_calibrate(int sock, struct lttng_ust_calibrate *calibrate)
 526 {
 527         if (!calibrate)
 528                 return -EINVAL;
 529
 530         return -ENOSYS;
 531 }
 532
 533 int ustctl_sock_flush_buffer(int sock, struct lttng_ust_object_data *object)
 534 {
 535         struct ustcomm_ust_msg lum;
 536         struct ustcomm_ust_reply lur;
 537         int ret;
 538
 539         if (!object)
 540                 return -EINVAL;
 541
 542         memset(&lum, 0, sizeof(lum));
 543         lum.handle = object->handle;
 544         lum.cmd = LTTNG_UST_FLUSH_BUFFER;
 545         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 546         if (ret)
 547                 return ret;
 548         DBG("flushed buffer handle %u", object->handle);
 549         return 0;
 550 }
 551
 552 /* Buffer operations */
 553
 554 /* Map channel shm into process memory */
 555 struct lttng_ust_shm_handle *ustctl_map_channel(struct lttng_ust_object_data *chan_data)
 556 {
 557         struct lttng_ust_shm_handle *handle;
 558         struct channel *chan;
 559         size_t chan_size;
 560         struct lttng_ust_lib_ring_buffer_config *config;
 561         int ret;
 562
 563         if (!chan_data)
 564                 return NULL;
 565
 566         handle = channel_handle_create(chan_data->shm_fd,
 567                 chan_data->wait_fd,
 568                 chan_data->memory_map_size);
 569         if (!handle) {
 570                 ERR("create handle error");
 571                 return NULL;
 572         }
 573         /*
 574          * Set to -1, and then close the shm fd, and set the handle shm
 575          * fd to -1 too. We don't need the shm fds after they have been
 576          * mapped.
 577          * The wait_fd is set to -1 in chan_data because it is now owned
 578          * by the handle.
 579          */
 580         chan_data->shm_fd = -1;
 581         chan_data->wait_fd = -1;
 582
 583         /* chan is object 0. This is hardcoded. */
 584         if (handle->table->objects[0].shm_fd >= 0) {
 585                 ret = close(handle->table->objects[0].shm_fd);
 586                 if (ret) {
 587                         perror("Error closing shm_fd");
 588                 }
 589                 handle->table->objects[0].shm_fd = -1;
 590         }
 591
 592         /*
 593          * TODO: add consistency checks to be resilient if the
 594          * application try to feed us with incoherent channel structure
 595          * values.
 596          */
 597         chan = shmp(handle, handle->chan);
 598         /* chan is object 0. This is hardcoded. */
 599         chan_size = handle->table->objects[0].allocated_len;
 600         handle->shadow_chan = malloc(chan_size);
 601         if (!handle->shadow_chan) {
 602                 channel_destroy(chan, handle, 1);
 603                 return NULL;
 604         }
 605         memcpy(handle->shadow_chan, chan, chan_size);
 606         /*
 607          * The callback pointers in the producer are invalid in the
 608          * consumer. We need to look them up here.
 609          */
 610         config = &handle->shadow_chan->backend.config;
 611         switch (config->client_type) {
 612         case LTTNG_CLIENT_METADATA:
 613                 memcpy(&config->cb, lttng_client_callbacks_metadata,
 614                         sizeof(config->cb));
 615                 break;
 616         case LTTNG_CLIENT_DISCARD:
 617                 memcpy(&config->cb, lttng_client_callbacks_discard,
 618                         sizeof(config->cb));
 619                 break;
 620         case LTTNG_CLIENT_OVERWRITE:
 621                 memcpy(&config->cb, lttng_client_callbacks_overwrite,
 622                         sizeof(config->cb));
 623                 break;
 624         default:
 625                 ERR("Unknown client type %d", config->client_type);
 626                 channel_destroy(chan, handle, 1);
 627                 return NULL;
 628         }
 629         /* Replace the object table pointer. */
 630         ret = munmap(handle->table->objects[0].memory_map,
 631                 handle->table->objects[0].memory_map_size);
 632         if (ret) {
 633                 perror("munmap");
 634                 assert(0);
 635         }
 636         handle->table->objects[0].memory_map = (char *) handle->shadow_chan;
 637         handle->table->objects[0].is_shadow = 1;
 638         return handle;
 639 }
 640
 641 /* Add stream to channel shm and map its shm into process memory */
 642 int ustctl_add_stream(struct lttng_ust_shm_handle *handle,
 643                 struct lttng_ust_object_data *stream_data)
 644 {
 645         int ret;
 646
 647         if (!handle || !stream_data)
 648                 return -EINVAL;
 649
 650         if (!stream_data->handle)
 651                 return -ENOENT;
 652         /* map stream */
 653         ret = channel_handle_add_stream(handle,
 654                 stream_data->shm_fd,
 655                 stream_data->wait_fd,
 656                 stream_data->memory_map_size);
 657         if (ret) {
 658                 ERR("add stream error\n");
 659                 return ret;
 660         }
 661         /*
 662          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 663          * of closing shm_fd and wait_fd.
 664          */
 665         stream_data->shm_fd = -1;
 666         stream_data->wait_fd = -1;
 667         return 0;
 668 }
 669
 670 void ustctl_unmap_channel(struct lttng_ust_shm_handle *handle)
 671 {
 672         struct channel *chan;
 673
 674         assert(handle);
 675         chan = shmp(handle, handle->chan);
 676         channel_destroy(chan, handle, 1);
 677 }
 678
 679 /*
 680  * ustctl closes the shm_fd fds after mapping it.
 681  */
 682 struct lttng_ust_lib_ring_buffer *ustctl_open_stream_read(struct lttng_ust_shm_handle *handle,
 683         int cpu)
 684 {
 685         struct channel *chan;
 686         int *shm_fd, *wait_fd;
 687         uint64_t *memory_map_size;
 688         struct lttng_ust_lib_ring_buffer *buf;
 689         int ret;
 690
 691         if (!handle)
 692                 return NULL;
 693
 694         chan = handle->shadow_chan;
 695         buf = channel_get_ring_buffer(&chan->backend.config,
 696                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 697         if (!buf)
 698                 return NULL;
 699         ret = lib_ring_buffer_open_read(buf, handle, 1);
 700         if (ret)
 701                 return NULL;
 702         /*
 703          * We can close shm_fd early, right after is has been mapped.
 704          */
 705         if (*shm_fd >= 0) {
 706                 ret = close(*shm_fd);
 707                 if (ret) {
 708                         perror("Error closing shm_fd");
 709                 }
 710                 *shm_fd = -1;
 711         }
 712         return buf;
 713 }
 714
 715 void ustctl_close_stream_read(struct lttng_ust_shm_handle *handle,
 716                 struct lttng_ust_lib_ring_buffer *buf)
 717 {
 718         assert(handle && buf);
 719         lib_ring_buffer_release_read(buf, handle, 1);
 720 }
 721
 722 /* For mmap mode, readable without "get" operation */
 723
 724 void *ustctl_get_mmap_base(struct lttng_ust_shm_handle *handle,
 725                 struct lttng_ust_lib_ring_buffer *buf)
 726 {
 727         if (!handle || !buf)
 728                 return NULL;
 729         return shmp(handle, buf->backend.memory_map);
 730 }
 731
 732 /* returns the length to mmap. */
 733 int ustctl_get_mmap_len(struct lttng_ust_shm_handle *handle,
 734                 struct lttng_ust_lib_ring_buffer *buf,
 735                 unsigned long *len)
 736 {
 737         unsigned long mmap_buf_len;
 738         struct channel *chan;
 739
 740         if (!handle || !buf || !len)
 741                 return -EINVAL;
 742
 743         chan = handle->shadow_chan;
 744         if (chan->backend.config.output != RING_BUFFER_MMAP)
 745                 return -EINVAL;
 746         mmap_buf_len = chan->backend.buf_size;
 747         if (chan->backend.extra_reader_sb)
 748                 mmap_buf_len += chan->backend.subbuf_size;
 749         if (mmap_buf_len > INT_MAX)
 750                 return -EFBIG;
 751         *len = mmap_buf_len;
 752         return 0;
 753 }
 754
 755 /* returns the maximum size for sub-buffers. */
 756 int ustctl_get_max_subbuf_size(struct lttng_ust_shm_handle *handle,
 757                 struct lttng_ust_lib_ring_buffer *buf,
 758                 unsigned long *len)
 759 {
 760         struct channel *chan;
 761
 762         if (!handle || !buf || !len)
 763                 return -EINVAL;
 764
 765         chan = handle->shadow_chan;
 766         *len = chan->backend.subbuf_size;
 767         return 0;
 768 }
 769
 770 /*
 771  * For mmap mode, operate on the current packet (between get/put or
 772  * get_next/put_next).
 773  */
 774
 775 /* returns the offset of the subbuffer belonging to the mmap reader. */
 776 int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
 777                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 778 {
 779         struct channel *chan;
 780         unsigned long sb_bindex;
 781
 782         if (!handle || !buf || !off)
 783                 return -EINVAL;
 784
 785         chan = handle->shadow_chan;
 786         if (chan->backend.config.output != RING_BUFFER_MMAP)
 787                 return -EINVAL;
 788         sb_bindex = subbuffer_id_get_index(&chan->backend.config,
 789                                            buf->backend.buf_rsb.id);
 790         *off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
 791         return 0;
 792 }
 793
 794 /* returns the size of the current sub-buffer, without padding (for mmap). */
 795 int ustctl_get_subbuf_size(struct lttng_ust_shm_handle *handle,
 796                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 797 {
 798         struct channel *chan;
 799
 800         if (!handle || !buf || !len)
 801                 return -EINVAL;
 802
 803         chan = handle->shadow_chan;
 804         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 805                 handle);
 806         return 0;
 807 }
 808
 809 /* returns the size of the current sub-buffer, without padding (for mmap). */
 810 int ustctl_get_padded_subbuf_size(struct lttng_ust_shm_handle *handle,
 811                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 812 {
 813         struct channel *chan;
 814
 815         if (!handle || !buf || !len)
 816                 return -EINVAL;
 817
 818         chan = handle->shadow_chan;
 819         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 820                 handle);
 821         *len = PAGE_ALIGN(*len);
 822         return 0;
 823 }
 824
 825 /* Get exclusive read access to the next sub-buffer that can be read. */
 826 int ustctl_get_next_subbuf(struct lttng_ust_shm_handle *handle,
 827                 struct lttng_ust_lib_ring_buffer *buf)
 828 {
 829         if (!handle || !buf)
 830                 return -EINVAL;
 831
 832         return lib_ring_buffer_get_next_subbuf(buf, handle);
 833 }
 834
 835
 836 /* Release exclusive sub-buffer access, move consumer forward. */
 837 int ustctl_put_next_subbuf(struct lttng_ust_shm_handle *handle,
 838                 struct lttng_ust_lib_ring_buffer *buf)
 839 {
 840         if (!handle || !buf)
 841                 return -EINVAL;
 842
 843         lib_ring_buffer_put_next_subbuf(buf, handle);
 844         return 0;
 845 }
 846
 847 /* snapshot */
 848
 849 /* Get a snapshot of the current ring buffer producer and consumer positions */
 850 int ustctl_snapshot(struct lttng_ust_shm_handle *handle,
 851                 struct lttng_ust_lib_ring_buffer *buf)
 852 {
 853         if (!handle || !buf)
 854                 return -EINVAL;
 855
 856         return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 857                         &buf->prod_snapshot, handle);
 858 }
 859
 860 /* Get the consumer position (iteration start) */
 861 int ustctl_snapshot_get_consumed(struct lttng_ust_shm_handle *handle,
 862                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 863 {
 864         if (!handle || !buf || !pos)
 865                 return -EINVAL;
 866
 867         *pos = buf->cons_snapshot;
 868         return 0;
 869 }
 870
 871 /* Get the producer position (iteration end) */
 872 int ustctl_snapshot_get_produced(struct lttng_ust_shm_handle *handle,
 873                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 874 {
 875         if (!handle || !buf || !pos)
 876                 return -EINVAL;
 877
 878         *pos = buf->prod_snapshot;
 879         return 0;
 880 }
 881
 882 /* Get exclusive read access to the specified sub-buffer position */
 883 int ustctl_get_subbuf(struct lttng_ust_shm_handle *handle,
 884                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 885 {
 886         if (!handle || !buf || !pos)
 887                 return -EINVAL;
 888
 889         return lib_ring_buffer_get_subbuf(buf, *pos, handle);
 890 }
 891
 892 /* Release exclusive sub-buffer access */
 893 int ustctl_put_subbuf(struct lttng_ust_shm_handle *handle,
 894                 struct lttng_ust_lib_ring_buffer *buf)
 895 {
 896         if (!handle || !buf)
 897                 return -EINVAL;
 898
 899         lib_ring_buffer_put_subbuf(buf, handle);
 900         return 0;
 901 }
 902
 903 void ustctl_flush_buffer(struct lttng_ust_shm_handle *handle,
 904                 struct lttng_ust_lib_ring_buffer *buf,
 905                 int producer_active)
 906 {
 907         assert(handle && buf);
 908         lib_ring_buffer_switch_slow(buf,
 909                 producer_active ? SWITCH_ACTIVE : SWITCH_FLUSH,
 910                 handle);
 911 }