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)
  55                         return ret;
  56         }
  57         return 0;
  58 }
  59 /*
  60  * If sock is negative, it means we don't have to notify the other side
  61  * (e.g. application has already vanished).
  62  */
  63 int ustctl_release_object(int sock, struct lttng_ust_object_data *data)
  64 {
  65         int ret;
  66
  67         if (!data)
  68                 return -EINVAL;
  69
  70         if (data->shm_fd >= 0) {
  71                 ret = close(data->shm_fd);
  72                 if (ret < 0) {
  73                         ret = -errno;
  74                         return ret;
  75                 }
  76         }
  77         if (data->wait_fd >= 0) {
  78                 ret = close(data->wait_fd);
  79                 if (ret < 0) {
  80                         ret = -errno;
  81                         return ret;
  82                 }
  83         }
  84         return ustctl_release_handle(sock, data->handle);
  85 }
  86
  87 /*
  88  * Send registration done packet to the application.
  89  */
  90 int ustctl_register_done(int sock)
  91 {
  92         struct ustcomm_ust_msg lum;
  93         struct ustcomm_ust_reply lur;
  94         int ret;
  95
  96         DBG("Sending register done command to %d", sock);
  97         memset(&lum, 0, sizeof(lum));
  98         lum.handle = LTTNG_UST_ROOT_HANDLE;
  99         lum.cmd = LTTNG_UST_REGISTER_DONE;
 100         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 101         if (ret)
 102                 return ret;
 103         return 0;
 104 }
 105
 106 /*
 107  * returns session handle.
 108  */
 109 int ustctl_create_session(int sock)
 110 {
 111         struct ustcomm_ust_msg lum;
 112         struct ustcomm_ust_reply lur;
 113         int ret, session_handle;
 114
 115         /* Create session */
 116         memset(&lum, 0, sizeof(lum));
 117         lum.handle = LTTNG_UST_ROOT_HANDLE;
 118         lum.cmd = LTTNG_UST_SESSION;
 119         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 120         if (ret)
 121                 return ret;
 122         session_handle = lur.ret_val;
 123         DBG("received session handle %u", session_handle);
 124         return session_handle;
 125 }
 126
 127 /* open the metadata global channel */
 128 int ustctl_open_metadata(int sock, int session_handle,
 129                 struct lttng_ust_channel_attr *chops,
 130                 struct lttng_ust_object_data **_metadata_data)
 131 {
 132         struct ustcomm_ust_msg lum;
 133         struct ustcomm_ust_reply lur;
 134         struct lttng_ust_object_data *metadata_data;
 135         int ret, err = 0;
 136
 137         if (!chops || !_metadata_data)
 138                 return -EINVAL;
 139
 140         metadata_data = malloc(sizeof(*metadata_data));
 141         if (!metadata_data)
 142                 return -ENOMEM;
 143         init_object(metadata_data);
 144         /* Create metadata channel */
 145         memset(&lum, 0, sizeof(lum));
 146         lum.handle = session_handle;
 147         lum.cmd = LTTNG_UST_METADATA;
 148         lum.u.channel.overwrite = chops->overwrite;
 149         lum.u.channel.subbuf_size = chops->subbuf_size;
 150         lum.u.channel.num_subbuf = chops->num_subbuf;
 151         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 152         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 153         lum.u.channel.output = chops->output;
 154         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 155         if (ret) {
 156                 free(metadata_data);
 157                 return ret;
 158         }
 159         metadata_data->handle = lur.ret_val;
 160         DBG("received metadata handle %u", metadata_data->handle);
 161         metadata_data->memory_map_size = lur.u.channel.memory_map_size;
 162         /* get shm fd */
 163         ret = ustcomm_recv_fd(sock);
 164         if (ret < 0)
 165                 err = ret;
 166         else
 167                 metadata_data->shm_fd = ret;
 168         /*
 169          * We need to get the second FD even if the first fails, because
 170          * libust expects us to read the two FDs.
 171          */
 172         /* get wait fd */
 173         ret = ustcomm_recv_fd(sock);
 174         if (ret < 0)
 175                 err = ret;
 176         else
 177                 metadata_data->wait_fd = ret;
 178         if (err)
 179                 goto error;
 180         *_metadata_data = metadata_data;
 181         return 0;
 182
 183 error:
 184         (void) ustctl_release_object(sock, metadata_data);
 185         free(metadata_data);
 186         return err;
 187 }
 188
 189 int ustctl_create_channel(int sock, int session_handle,
 190                 struct lttng_ust_channel_attr *chops,
 191                 struct lttng_ust_object_data **_channel_data)
 192 {
 193         struct ustcomm_ust_msg lum;
 194         struct ustcomm_ust_reply lur;
 195         struct lttng_ust_object_data *channel_data;
 196         int ret, err = 0;
 197
 198         if (!chops || !_channel_data)
 199                 return -EINVAL;
 200
 201         channel_data = malloc(sizeof(*channel_data));
 202         if (!channel_data)
 203                 return -ENOMEM;
 204         init_object(channel_data);
 205         /* Create metadata channel */
 206         memset(&lum, 0, sizeof(lum));
 207         lum.handle = session_handle;
 208         lum.cmd = LTTNG_UST_CHANNEL;
 209         lum.u.channel.overwrite = chops->overwrite;
 210         lum.u.channel.subbuf_size = chops->subbuf_size;
 211         lum.u.channel.num_subbuf = chops->num_subbuf;
 212         lum.u.channel.switch_timer_interval = chops->switch_timer_interval;
 213         lum.u.channel.read_timer_interval = chops->read_timer_interval;
 214         lum.u.channel.output = chops->output;
 215         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 216         if (ret) {
 217                 free(channel_data);
 218                 return ret;
 219         }
 220         channel_data->handle = lur.ret_val;
 221         DBG("received channel handle %u", channel_data->handle);
 222         channel_data->memory_map_size = lur.u.channel.memory_map_size;
 223         /* get shm fd */
 224         ret = ustcomm_recv_fd(sock);
 225         if (ret < 0)
 226                 err = ret;
 227         else
 228                 channel_data->shm_fd = ret;
 229         /*
 230          * We need to get the second FD even if the first fails, because
 231          * libust expects us to read the two FDs.
 232          */
 233         /* get wait fd */
 234         ret = ustcomm_recv_fd(sock);
 235         if (ret < 0)
 236                 err = ret;
 237         else
 238                 channel_data->wait_fd = ret;
 239         if (err)
 240                 goto error;
 241         *_channel_data = channel_data;
 242         return 0;
 243
 244 error:
 245         (void) ustctl_release_object(sock, channel_data);
 246         free(channel_data);
 247         return err;
 248 }
 249
 250 /*
 251  * Return -ENOENT if no more stream is available for creation.
 252  * Return 0 on success.
 253  * Return negative error value on system error.
 254  * Return positive error value on UST error.
 255  */
 256 int ustctl_create_stream(int sock, struct lttng_ust_object_data *channel_data,
 257                 struct lttng_ust_object_data **_stream_data)
 258 {
 259         struct ustcomm_ust_msg lum;
 260         struct ustcomm_ust_reply lur;
 261         struct lttng_ust_object_data *stream_data;
 262         int ret, fd, err = 0;
 263
 264         if (!channel_data || !_stream_data)
 265                 return -EINVAL;
 266
 267         stream_data = malloc(sizeof(*stream_data));
 268         if (!stream_data)
 269                 return -ENOMEM;
 270         init_object(stream_data);
 271         memset(&lum, 0, sizeof(lum));
 272         lum.handle = channel_data->handle;
 273         lum.cmd = LTTNG_UST_STREAM;
 274         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 275         if (ret) {
 276                 free(stream_data);
 277                 return ret;
 278         }
 279         stream_data->handle = lur.ret_val;
 280         DBG("received stream handle %u", stream_data->handle);
 281         stream_data->memory_map_size = lur.u.stream.memory_map_size;
 282         /* get shm fd */
 283         fd = ustcomm_recv_fd(sock);
 284         if (fd < 0)
 285                 err = fd;
 286         else
 287                 stream_data->shm_fd = fd;
 288         /*
 289          * We need to get the second FD even if the first fails, because
 290          * libust expects us to read the two FDs.
 291          */
 292         /* get wait fd */
 293         fd = ustcomm_recv_fd(sock);
 294         if (fd < 0)
 295                 err = fd;
 296         else
 297                 stream_data->wait_fd = fd;
 298         if (err)
 299                 goto error;
 300         *_stream_data = stream_data;
 301         return ret;
 302
 303 error:
 304         (void) ustctl_release_object(sock, stream_data);
 305         free(stream_data);
 306         return err;
 307 }
 308
 309 int ustctl_create_event(int sock, struct lttng_ust_event *ev,
 310                 struct lttng_ust_object_data *channel_data,
 311                 struct lttng_ust_object_data **_event_data)
 312 {
 313         struct ustcomm_ust_msg lum;
 314         struct ustcomm_ust_reply lur;
 315         struct lttng_ust_object_data *event_data;
 316         int ret;
 317
 318         if (!channel_data || !_event_data)
 319                 return -EINVAL;
 320
 321         event_data = malloc(sizeof(*event_data));
 322         if (!event_data)
 323                 return -ENOMEM;
 324         init_object(event_data);
 325         memset(&lum, 0, sizeof(lum));
 326         lum.handle = channel_data->handle;
 327         lum.cmd = LTTNG_UST_EVENT;
 328         strncpy(lum.u.event.name, ev->name,
 329                 LTTNG_UST_SYM_NAME_LEN);
 330         lum.u.event.instrumentation = ev->instrumentation;
 331         lum.u.event.loglevel_type = ev->loglevel_type;
 332         lum.u.event.loglevel = ev->loglevel;
 333         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 334         if (ret) {
 335                 free(event_data);
 336                 return ret;
 337         }
 338         event_data->handle = lur.ret_val;
 339         DBG("received event handle %u", event_data->handle);
 340         *_event_data = event_data;
 341         return 0;
 342 }
 343
 344 int ustctl_add_context(int sock, struct lttng_ust_context *ctx,
 345                 struct lttng_ust_object_data *obj_data,
 346                 struct lttng_ust_object_data **_context_data)
 347 {
 348         struct ustcomm_ust_msg lum;
 349         struct ustcomm_ust_reply lur;
 350         struct lttng_ust_object_data *context_data;
 351         int ret;
 352
 353         if (!obj_data || !_context_data)
 354                 return -EINVAL;
 355
 356         context_data = malloc(sizeof(*context_data));
 357         if (!context_data)
 358                 return -ENOMEM;
 359         init_object(context_data);
 360         memset(&lum, 0, sizeof(lum));
 361         lum.handle = obj_data->handle;
 362         lum.cmd = LTTNG_UST_CONTEXT;
 363         lum.u.context.ctx = ctx->ctx;
 364         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 365         if (ret) {
 366                 free(context_data);
 367                 return ret;
 368         }
 369         context_data->handle = lur.ret_val;
 370         DBG("received context handle %u", context_data->handle);
 371         *_context_data = context_data;
 372         return ret;
 373 }
 374
 375 int ustctl_set_filter(int sock, struct lttng_ust_filter_bytecode *bytecode,
 376                 struct lttng_ust_object_data *obj_data)
 377 {
 378         struct ustcomm_ust_msg lum;
 379         struct ustcomm_ust_reply lur;
 380         int ret;
 381
 382         if (!obj_data)
 383                 return -EINVAL;
 384
 385         memset(&lum, 0, sizeof(lum));
 386         lum.handle = obj_data->handle;
 387         lum.cmd = LTTNG_UST_FILTER;
 388         lum.u.filter.data_size = bytecode->len;
 389         lum.u.filter.reloc_offset = bytecode->reloc_offset;
 390
 391         ret = ustcomm_send_app_msg(sock, &lum);
 392         if (ret)
 393                 return ret;
 394         /* send var len bytecode */
 395         ret = ustcomm_send_unix_sock(sock, bytecode->data,
 396                                 bytecode->len);
 397         if (ret < 0) {
 398                 if (ret == -ECONNRESET)
 399                         fprintf(stderr, "remote end closed connection\n");
 400                 return ret;
 401         }
 402         if (ret != bytecode->len)
 403                 return -EINVAL;
 404         return ustcomm_recv_app_reply(sock, &lur, lum.handle, lum.cmd);
 405 }
 406
 407 /* Enable event, channel and session ioctl */
 408 int ustctl_enable(int sock, struct lttng_ust_object_data *object)
 409 {
 410         struct ustcomm_ust_msg lum;
 411         struct ustcomm_ust_reply lur;
 412         int ret;
 413
 414         if (!object)
 415                 return -EINVAL;
 416
 417         memset(&lum, 0, sizeof(lum));
 418         lum.handle = object->handle;
 419         lum.cmd = LTTNG_UST_ENABLE;
 420         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 421         if (ret)
 422                 return ret;
 423         DBG("enabled handle %u", object->handle);
 424         return 0;
 425 }
 426
 427 /* Disable event, channel and session ioctl */
 428 int ustctl_disable(int sock, struct lttng_ust_object_data *object)
 429 {
 430         struct ustcomm_ust_msg lum;
 431         struct ustcomm_ust_reply lur;
 432         int ret;
 433
 434         if (!object)
 435                 return -EINVAL;
 436
 437         memset(&lum, 0, sizeof(lum));
 438         lum.handle = object->handle;
 439         lum.cmd = LTTNG_UST_DISABLE;
 440         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 441         if (ret)
 442                 return ret;
 443         DBG("disable handle %u", object->handle);
 444         return 0;
 445 }
 446
 447 int ustctl_start_session(int sock, int handle)
 448 {
 449         struct lttng_ust_object_data obj;
 450
 451         obj.handle = handle;
 452         return ustctl_enable(sock, &obj);
 453 }
 454
 455 int ustctl_stop_session(int sock, int handle)
 456 {
 457         struct lttng_ust_object_data obj;
 458
 459         obj.handle = handle;
 460         return ustctl_disable(sock, &obj);
 461 }
 462
 463 int ustctl_tracepoint_list(int sock)
 464 {
 465         struct ustcomm_ust_msg lum;
 466         struct ustcomm_ust_reply lur;
 467         int ret, tp_list_handle;
 468
 469         memset(&lum, 0, sizeof(lum));
 470         lum.handle = LTTNG_UST_ROOT_HANDLE;
 471         lum.cmd = LTTNG_UST_TRACEPOINT_LIST;
 472         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 473         if (ret)
 474                 return ret;
 475         tp_list_handle = lur.ret_val;
 476         DBG("received tracepoint list handle %u", tp_list_handle);
 477         return tp_list_handle;
 478 }
 479
 480 int ustctl_tracepoint_list_get(int sock, int tp_list_handle,
 481                 struct lttng_ust_tracepoint_iter *iter)
 482 {
 483         struct ustcomm_ust_msg lum;
 484         struct ustcomm_ust_reply lur;
 485         int ret;
 486
 487         if (!iter)
 488                 return -EINVAL;
 489
 490         memset(&lum, 0, sizeof(lum));
 491         lum.handle = tp_list_handle;
 492         lum.cmd = LTTNG_UST_TRACEPOINT_LIST_GET;
 493         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 494         if (ret)
 495                 return ret;
 496         DBG("received tracepoint list entry name %s loglevel %d",
 497                 lur.u.tracepoint.name,
 498                 lur.u.tracepoint.loglevel);
 499         memcpy(iter, &lur.u.tracepoint, sizeof(*iter));
 500         return 0;
 501 }
 502
 503 int ustctl_tracepoint_field_list(int sock)
 504 {
 505         struct ustcomm_ust_msg lum;
 506         struct ustcomm_ust_reply lur;
 507         int ret, tp_field_list_handle;
 508
 509         memset(&lum, 0, sizeof(lum));
 510         lum.handle = LTTNG_UST_ROOT_HANDLE;
 511         lum.cmd = LTTNG_UST_TRACEPOINT_FIELD_LIST;
 512         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 513         if (ret)
 514                 return ret;
 515         tp_field_list_handle = lur.ret_val;
 516         DBG("received tracepoint field list handle %u", tp_field_list_handle);
 517         return tp_field_list_handle;
 518 }
 519
 520 int ustctl_tracepoint_field_list_get(int sock, int tp_field_list_handle,
 521                 struct lttng_ust_field_iter *iter)
 522 {
 523         struct ustcomm_ust_msg lum;
 524         struct ustcomm_ust_reply lur;
 525         int ret;
 526         ssize_t len;
 527
 528         if (!iter)
 529                 return -EINVAL;
 530
 531         memset(&lum, 0, sizeof(lum));
 532         lum.handle = tp_field_list_handle;
 533         lum.cmd = LTTNG_UST_TRACEPOINT_FIELD_LIST_GET;
 534         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 535         if (ret)
 536                 return ret;
 537         len = ustcomm_recv_unix_sock(sock, iter, sizeof(*iter));
 538         if (len != sizeof(*iter)) {
 539                 return -EINVAL;
 540         }
 541         DBG("received tracepoint field list entry event_name %s event_loglevel %d field_name %s field_type %d",
 542                 iter->event_name,
 543                 iter->loglevel,
 544                 iter->field_name,
 545                 iter->type);
 546         return 0;
 547 }
 548
 549 int ustctl_tracer_version(int sock, struct lttng_ust_tracer_version *v)
 550 {
 551         struct ustcomm_ust_msg lum;
 552         struct ustcomm_ust_reply lur;
 553         int ret;
 554
 555         if (!v)
 556                 return -EINVAL;
 557
 558         memset(&lum, 0, sizeof(lum));
 559         lum.handle = LTTNG_UST_ROOT_HANDLE;
 560         lum.cmd = LTTNG_UST_TRACER_VERSION;
 561         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 562         if (ret)
 563                 return ret;
 564         memcpy(v, &lur.u.version, sizeof(*v));
 565         DBG("received tracer version");
 566         return 0;
 567 }
 568
 569 int ustctl_wait_quiescent(int sock)
 570 {
 571         struct ustcomm_ust_msg lum;
 572         struct ustcomm_ust_reply lur;
 573         int ret;
 574
 575         memset(&lum, 0, sizeof(lum));
 576         lum.handle = LTTNG_UST_ROOT_HANDLE;
 577         lum.cmd = LTTNG_UST_WAIT_QUIESCENT;
 578         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 579         if (ret)
 580                 return ret;
 581         DBG("waited for quiescent state");
 582         return 0;
 583 }
 584
 585 int ustctl_calibrate(int sock, struct lttng_ust_calibrate *calibrate)
 586 {
 587         if (!calibrate)
 588                 return -EINVAL;
 589
 590         return -ENOSYS;
 591 }
 592
 593 int ustctl_sock_flush_buffer(int sock, struct lttng_ust_object_data *object)
 594 {
 595         struct ustcomm_ust_msg lum;
 596         struct ustcomm_ust_reply lur;
 597         int ret;
 598
 599         if (!object)
 600                 return -EINVAL;
 601
 602         memset(&lum, 0, sizeof(lum));
 603         lum.handle = object->handle;
 604         lum.cmd = LTTNG_UST_FLUSH_BUFFER;
 605         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 606         if (ret)
 607                 return ret;
 608         DBG("flushed buffer handle %u", object->handle);
 609         return 0;
 610 }
 611
 612 /* Buffer operations */
 613
 614 /* Map channel shm into process memory */
 615 struct lttng_ust_shm_handle *ustctl_map_channel(struct lttng_ust_object_data *chan_data)
 616 {
 617         struct lttng_ust_shm_handle *handle;
 618         struct channel *chan;
 619         size_t chan_size;
 620         struct lttng_ust_lib_ring_buffer_config *config;
 621         int ret;
 622
 623         if (!chan_data)
 624                 return NULL;
 625
 626         handle = channel_handle_create(chan_data->shm_fd,
 627                 chan_data->wait_fd,
 628                 chan_data->memory_map_size);
 629         if (!handle) {
 630                 ERR("create handle error");
 631                 return NULL;
 632         }
 633         /*
 634          * Set to -1, and then close the shm fd, and set the handle shm
 635          * fd to -1 too. We don't need the shm fds after they have been
 636          * mapped.
 637          * The wait_fd is set to -1 in chan_data because it is now owned
 638          * by the handle.
 639          */
 640         chan_data->shm_fd = -1;
 641         chan_data->wait_fd = -1;
 642
 643         /* chan is object 0. This is hardcoded. */
 644         if (handle->table->objects[0].shm_fd >= 0) {
 645                 ret = close(handle->table->objects[0].shm_fd);
 646                 if (ret) {
 647                         perror("Error closing shm_fd");
 648                 }
 649                 handle->table->objects[0].shm_fd = -1;
 650         }
 651
 652         /*
 653          * TODO: add consistency checks to be resilient if the
 654          * application try to feed us with incoherent channel structure
 655          * values.
 656          */
 657         chan = shmp(handle, handle->chan);
 658         /* chan is object 0. This is hardcoded. */
 659         chan_size = handle->table->objects[0].allocated_len;
 660         handle->shadow_chan = malloc(chan_size);
 661         if (!handle->shadow_chan) {
 662                 channel_destroy(chan, handle, 1);
 663                 return NULL;
 664         }
 665         memcpy(handle->shadow_chan, chan, chan_size);
 666         /*
 667          * The callback pointers in the producer are invalid in the
 668          * consumer. We need to look them up here.
 669          */
 670         config = &handle->shadow_chan->backend.config;
 671         switch (config->client_type) {
 672         case LTTNG_CLIENT_METADATA:
 673                 memcpy(&config->cb, lttng_client_callbacks_metadata,
 674                         sizeof(config->cb));
 675                 break;
 676         case LTTNG_CLIENT_DISCARD:
 677                 memcpy(&config->cb, lttng_client_callbacks_discard,
 678                         sizeof(config->cb));
 679                 break;
 680         case LTTNG_CLIENT_OVERWRITE:
 681                 memcpy(&config->cb, lttng_client_callbacks_overwrite,
 682                         sizeof(config->cb));
 683                 break;
 684         default:
 685                 ERR("Unknown client type %d", config->client_type);
 686                 channel_destroy(chan, handle, 1);
 687                 return NULL;
 688         }
 689         /* Replace the object table pointer. */
 690         ret = munmap(handle->table->objects[0].memory_map,
 691                 handle->table->objects[0].memory_map_size);
 692         if (ret) {
 693                 perror("munmap");
 694                 assert(0);
 695         }
 696         handle->table->objects[0].memory_map = (char *) handle->shadow_chan;
 697         handle->table->objects[0].is_shadow = 1;
 698         return handle;
 699 }
 700
 701 /* Add stream to channel shm and map its shm into process memory */
 702 int ustctl_add_stream(struct lttng_ust_shm_handle *handle,
 703                 struct lttng_ust_object_data *stream_data)
 704 {
 705         int ret;
 706
 707         if (!handle || !stream_data)
 708                 return -EINVAL;
 709
 710         if (!stream_data->handle)
 711                 return -ENOENT;
 712         /* map stream */
 713         ret = channel_handle_add_stream(handle,
 714                 stream_data->shm_fd,
 715                 stream_data->wait_fd,
 716                 stream_data->memory_map_size);
 717         if (ret) {
 718                 ERR("add stream error\n");
 719                 return ret;
 720         }
 721         /*
 722          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 723          * of closing shm_fd and wait_fd.
 724          */
 725         stream_data->shm_fd = -1;
 726         stream_data->wait_fd = -1;
 727         return 0;
 728 }
 729
 730 void ustctl_unmap_channel(struct lttng_ust_shm_handle *handle)
 731 {
 732         struct channel *chan;
 733
 734         assert(handle);
 735         chan = shmp(handle, handle->chan);
 736         channel_destroy(chan, handle, 1);
 737 }
 738
 739 /*
 740  * ustctl closes the shm_fd fds after mapping it.
 741  */
 742 struct lttng_ust_lib_ring_buffer *ustctl_open_stream_read(struct lttng_ust_shm_handle *handle,
 743         int cpu)
 744 {
 745         struct channel *chan;
 746         int *shm_fd, *wait_fd;
 747         uint64_t *memory_map_size;
 748         struct lttng_ust_lib_ring_buffer *buf;
 749         int ret;
 750
 751         if (!handle)
 752                 return NULL;
 753
 754         chan = handle->shadow_chan;
 755         buf = channel_get_ring_buffer(&chan->backend.config,
 756                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 757         if (!buf)
 758                 return NULL;
 759         ret = lib_ring_buffer_open_read(buf, handle, 1);
 760         if (ret)
 761                 return NULL;
 762         /*
 763          * We can close shm_fd early, right after is has been mapped.
 764          */
 765         if (*shm_fd >= 0) {
 766                 ret = close(*shm_fd);
 767                 if (ret) {
 768                         perror("Error closing shm_fd");
 769                 }
 770                 *shm_fd = -1;
 771         }
 772         return buf;
 773 }
 774
 775 void ustctl_close_stream_read(struct lttng_ust_shm_handle *handle,
 776                 struct lttng_ust_lib_ring_buffer *buf)
 777 {
 778         assert(handle && buf);
 779         lib_ring_buffer_release_read(buf, handle, 1);
 780 }
 781
 782 /* For mmap mode, readable without "get" operation */
 783
 784 void *ustctl_get_mmap_base(struct lttng_ust_shm_handle *handle,
 785                 struct lttng_ust_lib_ring_buffer *buf)
 786 {
 787         if (!handle || !buf)
 788                 return NULL;
 789         return shmp(handle, buf->backend.memory_map);
 790 }
 791
 792 /* returns the length to mmap. */
 793 int ustctl_get_mmap_len(struct lttng_ust_shm_handle *handle,
 794                 struct lttng_ust_lib_ring_buffer *buf,
 795                 unsigned long *len)
 796 {
 797         unsigned long mmap_buf_len;
 798         struct channel *chan;
 799
 800         if (!handle || !buf || !len)
 801                 return -EINVAL;
 802
 803         chan = handle->shadow_chan;
 804         if (chan->backend.config.output != RING_BUFFER_MMAP)
 805                 return -EINVAL;
 806         mmap_buf_len = chan->backend.buf_size;
 807         if (chan->backend.extra_reader_sb)
 808                 mmap_buf_len += chan->backend.subbuf_size;
 809         if (mmap_buf_len > INT_MAX)
 810                 return -EFBIG;
 811         *len = mmap_buf_len;
 812         return 0;
 813 }
 814
 815 /* returns the maximum size for sub-buffers. */
 816 int ustctl_get_max_subbuf_size(struct lttng_ust_shm_handle *handle,
 817                 struct lttng_ust_lib_ring_buffer *buf,
 818                 unsigned long *len)
 819 {
 820         struct channel *chan;
 821
 822         if (!handle || !buf || !len)
 823                 return -EINVAL;
 824
 825         chan = handle->shadow_chan;
 826         *len = chan->backend.subbuf_size;
 827         return 0;
 828 }
 829
 830 /*
 831  * For mmap mode, operate on the current packet (between get/put or
 832  * get_next/put_next).
 833  */
 834
 835 /* returns the offset of the subbuffer belonging to the mmap reader. */
 836 int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
 837                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 838 {
 839         struct channel *chan;
 840         unsigned long sb_bindex;
 841
 842         if (!handle || !buf || !off)
 843                 return -EINVAL;
 844
 845         chan = handle->shadow_chan;
 846         if (chan->backend.config.output != RING_BUFFER_MMAP)
 847                 return -EINVAL;
 848         sb_bindex = subbuffer_id_get_index(&chan->backend.config,
 849                                            buf->backend.buf_rsb.id);
 850         *off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
 851         return 0;
 852 }
 853
 854 /* returns the size of the current sub-buffer, without padding (for mmap). */
 855 int ustctl_get_subbuf_size(struct lttng_ust_shm_handle *handle,
 856                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 857 {
 858         struct channel *chan;
 859
 860         if (!handle || !buf || !len)
 861                 return -EINVAL;
 862
 863         chan = handle->shadow_chan;
 864         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 865                 handle);
 866         return 0;
 867 }
 868
 869 /* returns the size of the current sub-buffer, without padding (for mmap). */
 870 int ustctl_get_padded_subbuf_size(struct lttng_ust_shm_handle *handle,
 871                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 872 {
 873         struct channel *chan;
 874
 875         if (!handle || !buf || !len)
 876                 return -EINVAL;
 877
 878         chan = handle->shadow_chan;
 879         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 880                 handle);
 881         *len = PAGE_ALIGN(*len);
 882         return 0;
 883 }
 884
 885 /* Get exclusive read access to the next sub-buffer that can be read. */
 886 int ustctl_get_next_subbuf(struct lttng_ust_shm_handle *handle,
 887                 struct lttng_ust_lib_ring_buffer *buf)
 888 {
 889         if (!handle || !buf)
 890                 return -EINVAL;
 891
 892         return lib_ring_buffer_get_next_subbuf(buf, handle);
 893 }
 894
 895
 896 /* Release exclusive sub-buffer access, move consumer forward. */
 897 int ustctl_put_next_subbuf(struct lttng_ust_shm_handle *handle,
 898                 struct lttng_ust_lib_ring_buffer *buf)
 899 {
 900         if (!handle || !buf)
 901                 return -EINVAL;
 902
 903         lib_ring_buffer_put_next_subbuf(buf, handle);
 904         return 0;
 905 }
 906
 907 /* snapshot */
 908
 909 /* Get a snapshot of the current ring buffer producer and consumer positions */
 910 int ustctl_snapshot(struct lttng_ust_shm_handle *handle,
 911                 struct lttng_ust_lib_ring_buffer *buf)
 912 {
 913         if (!handle || !buf)
 914                 return -EINVAL;
 915
 916         return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 917                         &buf->prod_snapshot, handle);
 918 }
 919
 920 /* Get the consumer position (iteration start) */
 921 int ustctl_snapshot_get_consumed(struct lttng_ust_shm_handle *handle,
 922                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 923 {
 924         if (!handle || !buf || !pos)
 925                 return -EINVAL;
 926
 927         *pos = buf->cons_snapshot;
 928         return 0;
 929 }
 930
 931 /* Get the producer position (iteration end) */
 932 int ustctl_snapshot_get_produced(struct lttng_ust_shm_handle *handle,
 933                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 934 {
 935         if (!handle || !buf || !pos)
 936                 return -EINVAL;
 937
 938         *pos = buf->prod_snapshot;
 939         return 0;
 940 }
 941
 942 /* Get exclusive read access to the specified sub-buffer position */
 943 int ustctl_get_subbuf(struct lttng_ust_shm_handle *handle,
 944                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 945 {
 946         if (!handle || !buf || !pos)
 947                 return -EINVAL;
 948
 949         return lib_ring_buffer_get_subbuf(buf, *pos, handle);
 950 }
 951
 952 /* Release exclusive sub-buffer access */
 953 int ustctl_put_subbuf(struct lttng_ust_shm_handle *handle,
 954                 struct lttng_ust_lib_ring_buffer *buf)
 955 {
 956         if (!handle || !buf)
 957                 return -EINVAL;
 958
 959         lib_ring_buffer_put_subbuf(buf, handle);
 960         return 0;
 961 }
 962
 963 void ustctl_flush_buffer(struct lttng_ust_shm_handle *handle,
 964                 struct lttng_ust_lib_ring_buffer *buf,
 965                 int producer_active)
 966 {
 967         assert(handle && buf);
 968         lib_ring_buffer_switch_slow(buf,
 969                 producer_active ? SWITCH_ACTIVE : SWITCH_FLUSH,
 970                 handle);
 971 }