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         lum.u.filter.seqnum = bytecode->seqnum;
 391
 392         ret = ustcomm_send_app_msg(sock, &lum);
 393         if (ret)
 394                 return ret;
 395         /* send var len bytecode */
 396         ret = ustcomm_send_unix_sock(sock, bytecode->data,
 397                                 bytecode->len);
 398         if (ret < 0) {
 399                 if (ret == -ECONNRESET)
 400                         fprintf(stderr, "remote end closed connection\n");
 401                 return ret;
 402         }
 403         if (ret != bytecode->len)
 404                 return -EINVAL;
 405         return ustcomm_recv_app_reply(sock, &lur, lum.handle, lum.cmd);
 406 }
 407
 408 /* Enable event, channel and session ioctl */
 409 int ustctl_enable(int sock, struct lttng_ust_object_data *object)
 410 {
 411         struct ustcomm_ust_msg lum;
 412         struct ustcomm_ust_reply lur;
 413         int ret;
 414
 415         if (!object)
 416                 return -EINVAL;
 417
 418         memset(&lum, 0, sizeof(lum));
 419         lum.handle = object->handle;
 420         lum.cmd = LTTNG_UST_ENABLE;
 421         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 422         if (ret)
 423                 return ret;
 424         DBG("enabled handle %u", object->handle);
 425         return 0;
 426 }
 427
 428 /* Disable event, channel and session ioctl */
 429 int ustctl_disable(int sock, struct lttng_ust_object_data *object)
 430 {
 431         struct ustcomm_ust_msg lum;
 432         struct ustcomm_ust_reply lur;
 433         int ret;
 434
 435         if (!object)
 436                 return -EINVAL;
 437
 438         memset(&lum, 0, sizeof(lum));
 439         lum.handle = object->handle;
 440         lum.cmd = LTTNG_UST_DISABLE;
 441         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 442         if (ret)
 443                 return ret;
 444         DBG("disable handle %u", object->handle);
 445         return 0;
 446 }
 447
 448 int ustctl_start_session(int sock, int handle)
 449 {
 450         struct lttng_ust_object_data obj;
 451
 452         obj.handle = handle;
 453         return ustctl_enable(sock, &obj);
 454 }
 455
 456 int ustctl_stop_session(int sock, int handle)
 457 {
 458         struct lttng_ust_object_data obj;
 459
 460         obj.handle = handle;
 461         return ustctl_disable(sock, &obj);
 462 }
 463
 464 int ustctl_tracepoint_list(int sock)
 465 {
 466         struct ustcomm_ust_msg lum;
 467         struct ustcomm_ust_reply lur;
 468         int ret, tp_list_handle;
 469
 470         memset(&lum, 0, sizeof(lum));
 471         lum.handle = LTTNG_UST_ROOT_HANDLE;
 472         lum.cmd = LTTNG_UST_TRACEPOINT_LIST;
 473         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 474         if (ret)
 475                 return ret;
 476         tp_list_handle = lur.ret_val;
 477         DBG("received tracepoint list handle %u", tp_list_handle);
 478         return tp_list_handle;
 479 }
 480
 481 int ustctl_tracepoint_list_get(int sock, int tp_list_handle,
 482                 struct lttng_ust_tracepoint_iter *iter)
 483 {
 484         struct ustcomm_ust_msg lum;
 485         struct ustcomm_ust_reply lur;
 486         int ret;
 487
 488         if (!iter)
 489                 return -EINVAL;
 490
 491         memset(&lum, 0, sizeof(lum));
 492         lum.handle = tp_list_handle;
 493         lum.cmd = LTTNG_UST_TRACEPOINT_LIST_GET;
 494         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 495         if (ret)
 496                 return ret;
 497         DBG("received tracepoint list entry name %s loglevel %d",
 498                 lur.u.tracepoint.name,
 499                 lur.u.tracepoint.loglevel);
 500         memcpy(iter, &lur.u.tracepoint, sizeof(*iter));
 501         return 0;
 502 }
 503
 504 int ustctl_tracepoint_field_list(int sock)
 505 {
 506         struct ustcomm_ust_msg lum;
 507         struct ustcomm_ust_reply lur;
 508         int ret, tp_field_list_handle;
 509
 510         memset(&lum, 0, sizeof(lum));
 511         lum.handle = LTTNG_UST_ROOT_HANDLE;
 512         lum.cmd = LTTNG_UST_TRACEPOINT_FIELD_LIST;
 513         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 514         if (ret)
 515                 return ret;
 516         tp_field_list_handle = lur.ret_val;
 517         DBG("received tracepoint field list handle %u", tp_field_list_handle);
 518         return tp_field_list_handle;
 519 }
 520
 521 int ustctl_tracepoint_field_list_get(int sock, int tp_field_list_handle,
 522                 struct lttng_ust_field_iter *iter)
 523 {
 524         struct ustcomm_ust_msg lum;
 525         struct ustcomm_ust_reply lur;
 526         int ret;
 527         ssize_t len;
 528
 529         if (!iter)
 530                 return -EINVAL;
 531
 532         memset(&lum, 0, sizeof(lum));
 533         lum.handle = tp_field_list_handle;
 534         lum.cmd = LTTNG_UST_TRACEPOINT_FIELD_LIST_GET;
 535         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 536         if (ret)
 537                 return ret;
 538         len = ustcomm_recv_unix_sock(sock, iter, sizeof(*iter));
 539         if (len != sizeof(*iter)) {
 540                 return -EINVAL;
 541         }
 542         DBG("received tracepoint field list entry event_name %s event_loglevel %d field_name %s field_type %d",
 543                 iter->event_name,
 544                 iter->loglevel,
 545                 iter->field_name,
 546                 iter->type);
 547         return 0;
 548 }
 549
 550 int ustctl_tracer_version(int sock, struct lttng_ust_tracer_version *v)
 551 {
 552         struct ustcomm_ust_msg lum;
 553         struct ustcomm_ust_reply lur;
 554         int ret;
 555
 556         if (!v)
 557                 return -EINVAL;
 558
 559         memset(&lum, 0, sizeof(lum));
 560         lum.handle = LTTNG_UST_ROOT_HANDLE;
 561         lum.cmd = LTTNG_UST_TRACER_VERSION;
 562         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 563         if (ret)
 564                 return ret;
 565         memcpy(v, &lur.u.version, sizeof(*v));
 566         DBG("received tracer version");
 567         return 0;
 568 }
 569
 570 int ustctl_wait_quiescent(int sock)
 571 {
 572         struct ustcomm_ust_msg lum;
 573         struct ustcomm_ust_reply lur;
 574         int ret;
 575
 576         memset(&lum, 0, sizeof(lum));
 577         lum.handle = LTTNG_UST_ROOT_HANDLE;
 578         lum.cmd = LTTNG_UST_WAIT_QUIESCENT;
 579         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 580         if (ret)
 581                 return ret;
 582         DBG("waited for quiescent state");
 583         return 0;
 584 }
 585
 586 int ustctl_calibrate(int sock, struct lttng_ust_calibrate *calibrate)
 587 {
 588         if (!calibrate)
 589                 return -EINVAL;
 590
 591         return -ENOSYS;
 592 }
 593
 594 int ustctl_sock_flush_buffer(int sock, struct lttng_ust_object_data *object)
 595 {
 596         struct ustcomm_ust_msg lum;
 597         struct ustcomm_ust_reply lur;
 598         int ret;
 599
 600         if (!object)
 601                 return -EINVAL;
 602
 603         memset(&lum, 0, sizeof(lum));
 604         lum.handle = object->handle;
 605         lum.cmd = LTTNG_UST_FLUSH_BUFFER;
 606         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 607         if (ret)
 608                 return ret;
 609         DBG("flushed buffer handle %u", object->handle);
 610         return 0;
 611 }
 612
 613 /* Buffer operations */
 614
 615 /* Map channel shm into process memory */
 616 struct lttng_ust_shm_handle *ustctl_map_channel(struct lttng_ust_object_data *chan_data)
 617 {
 618         struct lttng_ust_shm_handle *handle;
 619         struct channel *chan;
 620         size_t chan_size;
 621         struct lttng_ust_lib_ring_buffer_config *config;
 622         int ret;
 623
 624         if (!chan_data)
 625                 return NULL;
 626
 627         handle = channel_handle_create(chan_data->shm_fd,
 628                 chan_data->wait_fd,
 629                 chan_data->memory_map_size);
 630         if (!handle) {
 631                 ERR("create handle error");
 632                 return NULL;
 633         }
 634         /*
 635          * Set to -1, and then close the shm fd, and set the handle shm
 636          * fd to -1 too. We don't need the shm fds after they have been
 637          * mapped.
 638          * The wait_fd is set to -1 in chan_data because it is now owned
 639          * by the handle.
 640          */
 641         chan_data->shm_fd = -1;
 642         chan_data->wait_fd = -1;
 643
 644         /* chan is object 0. This is hardcoded. */
 645         if (handle->table->objects[0].shm_fd >= 0) {
 646                 ret = close(handle->table->objects[0].shm_fd);
 647                 if (ret) {
 648                         perror("Error closing shm_fd");
 649                 }
 650                 handle->table->objects[0].shm_fd = -1;
 651         }
 652
 653         /*
 654          * TODO: add consistency checks to be resilient if the
 655          * application try to feed us with incoherent channel structure
 656          * values.
 657          */
 658         chan = shmp(handle, handle->chan);
 659         /* chan is object 0. This is hardcoded. */
 660         chan_size = handle->table->objects[0].allocated_len;
 661         handle->shadow_chan = malloc(chan_size);
 662         if (!handle->shadow_chan) {
 663                 channel_destroy(chan, handle, 1);
 664                 return NULL;
 665         }
 666         memcpy(handle->shadow_chan, chan, chan_size);
 667         /*
 668          * The callback pointers in the producer are invalid in the
 669          * consumer. We need to look them up here.
 670          */
 671         config = &handle->shadow_chan->backend.config;
 672         switch (config->client_type) {
 673         case LTTNG_CLIENT_METADATA:
 674                 memcpy(&config->cb, lttng_client_callbacks_metadata,
 675                         sizeof(config->cb));
 676                 break;
 677         case LTTNG_CLIENT_DISCARD:
 678                 memcpy(&config->cb, lttng_client_callbacks_discard,
 679                         sizeof(config->cb));
 680                 break;
 681         case LTTNG_CLIENT_OVERWRITE:
 682                 memcpy(&config->cb, lttng_client_callbacks_overwrite,
 683                         sizeof(config->cb));
 684                 break;
 685         default:
 686                 ERR("Unknown client type %d", config->client_type);
 687                 channel_destroy(chan, handle, 1);
 688                 return NULL;
 689         }
 690         /* Replace the object table pointer. */
 691         ret = munmap(handle->table->objects[0].memory_map,
 692                 handle->table->objects[0].memory_map_size);
 693         if (ret) {
 694                 perror("munmap");
 695                 assert(0);
 696         }
 697         handle->table->objects[0].memory_map = (char *) handle->shadow_chan;
 698         handle->table->objects[0].is_shadow = 1;
 699         return handle;
 700 }
 701
 702 /* Add stream to channel shm and map its shm into process memory */
 703 int ustctl_add_stream(struct lttng_ust_shm_handle *handle,
 704                 struct lttng_ust_object_data *stream_data)
 705 {
 706         int ret;
 707
 708         if (!handle || !stream_data)
 709                 return -EINVAL;
 710
 711         if (!stream_data->handle)
 712                 return -ENOENT;
 713         /* map stream */
 714         ret = channel_handle_add_stream(handle,
 715                 stream_data->shm_fd,
 716                 stream_data->wait_fd,
 717                 stream_data->memory_map_size);
 718         if (ret) {
 719                 ERR("add stream error\n");
 720                 return ret;
 721         }
 722         /*
 723          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 724          * of closing shm_fd and wait_fd.
 725          */
 726         stream_data->shm_fd = -1;
 727         stream_data->wait_fd = -1;
 728         return 0;
 729 }
 730
 731 void ustctl_unmap_channel(struct lttng_ust_shm_handle *handle)
 732 {
 733         struct channel *chan;
 734
 735         assert(handle);
 736         chan = shmp(handle, handle->chan);
 737         channel_destroy(chan, handle, 1);
 738 }
 739
 740 /*
 741  * ustctl closes the shm_fd fds after mapping it.
 742  */
 743 struct lttng_ust_lib_ring_buffer *ustctl_open_stream_read(struct lttng_ust_shm_handle *handle,
 744         int cpu)
 745 {
 746         struct channel *chan;
 747         int *shm_fd, *wait_fd;
 748         uint64_t *memory_map_size;
 749         struct lttng_ust_lib_ring_buffer *buf;
 750         int ret;
 751
 752         if (!handle)
 753                 return NULL;
 754
 755         chan = handle->shadow_chan;
 756         buf = channel_get_ring_buffer(&chan->backend.config,
 757                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 758         if (!buf)
 759                 return NULL;
 760         ret = lib_ring_buffer_open_read(buf, handle, 1);
 761         if (ret)
 762                 return NULL;
 763         /*
 764          * We can close shm_fd early, right after is has been mapped.
 765          */
 766         if (*shm_fd >= 0) {
 767                 ret = close(*shm_fd);
 768                 if (ret) {
 769                         perror("Error closing shm_fd");
 770                 }
 771                 *shm_fd = -1;
 772         }
 773         return buf;
 774 }
 775
 776 void ustctl_close_stream_read(struct lttng_ust_shm_handle *handle,
 777                 struct lttng_ust_lib_ring_buffer *buf)
 778 {
 779         assert(handle && buf);
 780         lib_ring_buffer_release_read(buf, handle, 1);
 781 }
 782
 783 /* For mmap mode, readable without "get" operation */
 784
 785 void *ustctl_get_mmap_base(struct lttng_ust_shm_handle *handle,
 786                 struct lttng_ust_lib_ring_buffer *buf)
 787 {
 788         if (!handle || !buf)
 789                 return NULL;
 790         return shmp(handle, buf->backend.memory_map);
 791 }
 792
 793 /* returns the length to mmap. */
 794 int ustctl_get_mmap_len(struct lttng_ust_shm_handle *handle,
 795                 struct lttng_ust_lib_ring_buffer *buf,
 796                 unsigned long *len)
 797 {
 798         unsigned long mmap_buf_len;
 799         struct channel *chan;
 800
 801         if (!handle || !buf || !len)
 802                 return -EINVAL;
 803
 804         chan = handle->shadow_chan;
 805         if (chan->backend.config.output != RING_BUFFER_MMAP)
 806                 return -EINVAL;
 807         mmap_buf_len = chan->backend.buf_size;
 808         if (chan->backend.extra_reader_sb)
 809                 mmap_buf_len += chan->backend.subbuf_size;
 810         if (mmap_buf_len > INT_MAX)
 811                 return -EFBIG;
 812         *len = mmap_buf_len;
 813         return 0;
 814 }
 815
 816 /* returns the maximum size for sub-buffers. */
 817 int ustctl_get_max_subbuf_size(struct lttng_ust_shm_handle *handle,
 818                 struct lttng_ust_lib_ring_buffer *buf,
 819                 unsigned long *len)
 820 {
 821         struct channel *chan;
 822
 823         if (!handle || !buf || !len)
 824                 return -EINVAL;
 825
 826         chan = handle->shadow_chan;
 827         *len = chan->backend.subbuf_size;
 828         return 0;
 829 }
 830
 831 /*
 832  * For mmap mode, operate on the current packet (between get/put or
 833  * get_next/put_next).
 834  */
 835
 836 /* returns the offset of the subbuffer belonging to the mmap reader. */
 837 int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
 838                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 839 {
 840         struct channel *chan;
 841         unsigned long sb_bindex;
 842
 843         if (!handle || !buf || !off)
 844                 return -EINVAL;
 845
 846         chan = handle->shadow_chan;
 847         if (chan->backend.config.output != RING_BUFFER_MMAP)
 848                 return -EINVAL;
 849         sb_bindex = subbuffer_id_get_index(&chan->backend.config,
 850                                            buf->backend.buf_rsb.id);
 851         *off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
 852         return 0;
 853 }
 854
 855 /* returns the size of the current sub-buffer, without padding (for mmap). */
 856 int ustctl_get_subbuf_size(struct lttng_ust_shm_handle *handle,
 857                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 858 {
 859         struct channel *chan;
 860
 861         if (!handle || !buf || !len)
 862                 return -EINVAL;
 863
 864         chan = handle->shadow_chan;
 865         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 866                 handle);
 867         return 0;
 868 }
 869
 870 /* returns the size of the current sub-buffer, without padding (for mmap). */
 871 int ustctl_get_padded_subbuf_size(struct lttng_ust_shm_handle *handle,
 872                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 873 {
 874         struct channel *chan;
 875
 876         if (!handle || !buf || !len)
 877                 return -EINVAL;
 878
 879         chan = handle->shadow_chan;
 880         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 881                 handle);
 882         *len = PAGE_ALIGN(*len);
 883         return 0;
 884 }
 885
 886 /* Get exclusive read access to the next sub-buffer that can be read. */
 887 int ustctl_get_next_subbuf(struct lttng_ust_shm_handle *handle,
 888                 struct lttng_ust_lib_ring_buffer *buf)
 889 {
 890         if (!handle || !buf)
 891                 return -EINVAL;
 892
 893         return lib_ring_buffer_get_next_subbuf(buf, handle);
 894 }
 895
 896
 897 /* Release exclusive sub-buffer access, move consumer forward. */
 898 int ustctl_put_next_subbuf(struct lttng_ust_shm_handle *handle,
 899                 struct lttng_ust_lib_ring_buffer *buf)
 900 {
 901         if (!handle || !buf)
 902                 return -EINVAL;
 903
 904         lib_ring_buffer_put_next_subbuf(buf, handle);
 905         return 0;
 906 }
 907
 908 /* snapshot */
 909
 910 /* Get a snapshot of the current ring buffer producer and consumer positions */
 911 int ustctl_snapshot(struct lttng_ust_shm_handle *handle,
 912                 struct lttng_ust_lib_ring_buffer *buf)
 913 {
 914         if (!handle || !buf)
 915                 return -EINVAL;
 916
 917         return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 918                         &buf->prod_snapshot, handle);
 919 }
 920
 921 /* Get the consumer position (iteration start) */
 922 int ustctl_snapshot_get_consumed(struct lttng_ust_shm_handle *handle,
 923                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 924 {
 925         if (!handle || !buf || !pos)
 926                 return -EINVAL;
 927
 928         *pos = buf->cons_snapshot;
 929         return 0;
 930 }
 931
 932 /* Get the producer position (iteration end) */
 933 int ustctl_snapshot_get_produced(struct lttng_ust_shm_handle *handle,
 934                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 935 {
 936         if (!handle || !buf || !pos)
 937                 return -EINVAL;
 938
 939         *pos = buf->prod_snapshot;
 940         return 0;
 941 }
 942
 943 /* Get exclusive read access to the specified sub-buffer position */
 944 int ustctl_get_subbuf(struct lttng_ust_shm_handle *handle,
 945                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 946 {
 947         if (!handle || !buf || !pos)
 948                 return -EINVAL;
 949
 950         return lib_ring_buffer_get_subbuf(buf, *pos, handle);
 951 }
 952
 953 /* Release exclusive sub-buffer access */
 954 int ustctl_put_subbuf(struct lttng_ust_shm_handle *handle,
 955                 struct lttng_ust_lib_ring_buffer *buf)
 956 {
 957         if (!handle || !buf)
 958                 return -EINVAL;
 959
 960         lib_ring_buffer_put_subbuf(buf, handle);
 961         return 0;
 962 }
 963
 964 void ustctl_flush_buffer(struct lttng_ust_shm_handle *handle,
 965                 struct lttng_ust_lib_ring_buffer *buf,
 966                 int producer_active)
 967 {
 968         assert(handle && buf);
 969         lib_ring_buffer_switch_slow(buf,
 970                 producer_active ? SWITCH_ACTIVE : SWITCH_FLUSH,
 971                 handle);
 972 }