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 int ustctl_set_filter(int sock, struct lttng_ust_filter_bytecode *bytecode,
 394                 struct lttng_ust_object_data *obj_data)
 395 {
 396         struct ustcomm_ust_msg lum;
 397         struct ustcomm_ust_reply lur;
 398         int ret;
 399
 400         if (!obj_data)
 401                 return -EINVAL;
 402
 403         memset(&lum, 0, sizeof(lum));
 404         lum.handle = obj_data->handle;
 405         lum.cmd = LTTNG_UST_FILTER;
 406         lum.u.filter.data_size = bytecode->len;
 407         lum.u.filter.reloc_offset = bytecode->reloc_offset;
 408
 409         ret = ustcomm_send_app_msg(sock, &lum);
 410         if (ret)
 411                 return ret;
 412         if (ret) {
 413                 return ret;
 414         }
 415         /* send var len bytecode */
 416         ret = ustcomm_send_unix_sock(sock, bytecode->data,
 417                                 bytecode->len);
 418         if (ret < 0) {
 419                 return ret;
 420         }
 421         ret = ustcomm_recv_app_reply(sock, &lur, lum.handle, lum.cmd);
 422         if (ret)
 423                 return ret;
 424         return ret;
 425 }
 426
 427 /* Enable event, channel and session ioctl */
 428 int ustctl_enable(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_ENABLE;
 440         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 441         if (ret)
 442                 return ret;
 443         DBG("enabled handle %u", object->handle);
 444         return 0;
 445 }
 446
 447 /* Disable event, channel and session ioctl */
 448 int ustctl_disable(int sock, struct lttng_ust_object_data *object)
 449 {
 450         struct ustcomm_ust_msg lum;
 451         struct ustcomm_ust_reply lur;
 452         int ret;
 453
 454         if (!object)
 455                 return -EINVAL;
 456
 457         memset(&lum, 0, sizeof(lum));
 458         lum.handle = object->handle;
 459         lum.cmd = LTTNG_UST_DISABLE;
 460         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 461         if (ret)
 462                 return ret;
 463         DBG("disable handle %u", object->handle);
 464         return 0;
 465 }
 466
 467 int ustctl_start_session(int sock, int handle)
 468 {
 469         struct lttng_ust_object_data obj;
 470
 471         obj.handle = handle;
 472         return ustctl_enable(sock, &obj);
 473 }
 474
 475 int ustctl_stop_session(int sock, int handle)
 476 {
 477         struct lttng_ust_object_data obj;
 478
 479         obj.handle = handle;
 480         return ustctl_disable(sock, &obj);
 481 }
 482
 483 int ustctl_tracepoint_list(int sock)
 484 {
 485         struct ustcomm_ust_msg lum;
 486         struct ustcomm_ust_reply lur;
 487         int ret, tp_list_handle;
 488
 489         memset(&lum, 0, sizeof(lum));
 490         lum.handle = LTTNG_UST_ROOT_HANDLE;
 491         lum.cmd = LTTNG_UST_TRACEPOINT_LIST;
 492         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 493         if (ret)
 494                 return ret;
 495         tp_list_handle = lur.ret_val;
 496         DBG("received tracepoint list handle %u", tp_list_handle);
 497         return tp_list_handle;
 498 }
 499
 500 int ustctl_tracepoint_list_get(int sock, int tp_list_handle,
 501                 struct lttng_ust_tracepoint_iter *iter)
 502 {
 503         struct ustcomm_ust_msg lum;
 504         struct ustcomm_ust_reply lur;
 505         int ret;
 506
 507         if (!iter)
 508                 return -EINVAL;
 509
 510         memset(&lum, 0, sizeof(lum));
 511         lum.handle = tp_list_handle;
 512         lum.cmd = LTTNG_UST_TRACEPOINT_LIST_GET;
 513         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 514         if (ret)
 515                 return ret;
 516         DBG("received tracepoint list entry name %s loglevel %d",
 517                 lur.u.tracepoint.name,
 518                 lur.u.tracepoint.loglevel);
 519         memcpy(iter, &lur.u.tracepoint, sizeof(*iter));
 520         return 0;
 521 }
 522
 523 int ustctl_tracepoint_field_list(int sock)
 524 {
 525         struct ustcomm_ust_msg lum;
 526         struct ustcomm_ust_reply lur;
 527         int ret, tp_field_list_handle;
 528
 529         memset(&lum, 0, sizeof(lum));
 530         lum.handle = LTTNG_UST_ROOT_HANDLE;
 531         lum.cmd = LTTNG_UST_TRACEPOINT_FIELD_LIST;
 532         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 533         if (ret)
 534                 return ret;
 535         tp_field_list_handle = lur.ret_val;
 536         DBG("received tracepoint field list handle %u", tp_field_list_handle);
 537         return tp_field_list_handle;
 538 }
 539
 540 int ustctl_tracepoint_field_list_get(int sock, int tp_field_list_handle,
 541                 struct lttng_ust_field_iter *iter)
 542 {
 543         struct ustcomm_ust_msg lum;
 544         struct ustcomm_ust_reply lur;
 545         int ret;
 546         ssize_t len;
 547
 548         if (!iter)
 549                 return -EINVAL;
 550
 551         memset(&lum, 0, sizeof(lum));
 552         lum.handle = tp_field_list_handle;
 553         lum.cmd = LTTNG_UST_TRACEPOINT_FIELD_LIST_GET;
 554         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 555         if (ret)
 556                 return ret;
 557         if (lur.ret_code != USTCOMM_OK) {
 558                 DBG("Return code: %s", ustcomm_get_readable_code(lur.ret_code));
 559                 return -EINVAL;
 560         }
 561         len = ustcomm_recv_unix_sock(sock, iter, sizeof(*iter));
 562         if (len != sizeof(*iter)) {
 563                 return -EINVAL;
 564         }
 565         DBG("received tracepoint field list entry event_name %s event_loglevel %d field_name %s field_type %d",
 566                 iter->event_name,
 567                 iter->loglevel,
 568                 iter->field_name,
 569                 iter->type);
 570         return 0;
 571 }
 572
 573 int ustctl_tracer_version(int sock, struct lttng_ust_tracer_version *v)
 574 {
 575         struct ustcomm_ust_msg lum;
 576         struct ustcomm_ust_reply lur;
 577         int ret;
 578
 579         if (!v)
 580                 return -EINVAL;
 581
 582         memset(&lum, 0, sizeof(lum));
 583         lum.handle = LTTNG_UST_ROOT_HANDLE;
 584         lum.cmd = LTTNG_UST_TRACER_VERSION;
 585         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 586         if (ret)
 587                 return ret;
 588         memcpy(v, &lur.u.version, sizeof(*v));
 589         DBG("received tracer version");
 590         return 0;
 591 }
 592
 593 int ustctl_wait_quiescent(int sock)
 594 {
 595         struct ustcomm_ust_msg lum;
 596         struct ustcomm_ust_reply lur;
 597         int ret;
 598
 599         memset(&lum, 0, sizeof(lum));
 600         lum.handle = LTTNG_UST_ROOT_HANDLE;
 601         lum.cmd = LTTNG_UST_WAIT_QUIESCENT;
 602         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 603         if (ret)
 604                 return ret;
 605         DBG("waited for quiescent state");
 606         return 0;
 607 }
 608
 609 int ustctl_calibrate(int sock, struct lttng_ust_calibrate *calibrate)
 610 {
 611         if (!calibrate)
 612                 return -EINVAL;
 613
 614         return -ENOSYS;
 615 }
 616
 617 int ustctl_sock_flush_buffer(int sock, struct lttng_ust_object_data *object)
 618 {
 619         struct ustcomm_ust_msg lum;
 620         struct ustcomm_ust_reply lur;
 621         int ret;
 622
 623         if (!object)
 624                 return -EINVAL;
 625
 626         memset(&lum, 0, sizeof(lum));
 627         lum.handle = object->handle;
 628         lum.cmd = LTTNG_UST_FLUSH_BUFFER;
 629         ret = ustcomm_send_app_cmd(sock, &lum, &lur);
 630         if (ret)
 631                 return ret;
 632         DBG("flushed buffer handle %u", object->handle);
 633         return 0;
 634 }
 635
 636 /* Buffer operations */
 637
 638 /* Map channel shm into process memory */
 639 struct lttng_ust_shm_handle *ustctl_map_channel(struct lttng_ust_object_data *chan_data)
 640 {
 641         struct lttng_ust_shm_handle *handle;
 642         struct channel *chan;
 643         size_t chan_size;
 644         struct lttng_ust_lib_ring_buffer_config *config;
 645         int ret;
 646
 647         if (!chan_data)
 648                 return NULL;
 649
 650         handle = channel_handle_create(chan_data->shm_fd,
 651                 chan_data->wait_fd,
 652                 chan_data->memory_map_size);
 653         if (!handle) {
 654                 ERR("create handle error");
 655                 return NULL;
 656         }
 657         /*
 658          * Set to -1, and then close the shm fd, and set the handle shm
 659          * fd to -1 too. We don't need the shm fds after they have been
 660          * mapped.
 661          * The wait_fd is set to -1 in chan_data because it is now owned
 662          * by the handle.
 663          */
 664         chan_data->shm_fd = -1;
 665         chan_data->wait_fd = -1;
 666
 667         /* chan is object 0. This is hardcoded. */
 668         if (handle->table->objects[0].shm_fd >= 0) {
 669                 ret = close(handle->table->objects[0].shm_fd);
 670                 if (ret) {
 671                         perror("Error closing shm_fd");
 672                 }
 673                 handle->table->objects[0].shm_fd = -1;
 674         }
 675
 676         /*
 677          * TODO: add consistency checks to be resilient if the
 678          * application try to feed us with incoherent channel structure
 679          * values.
 680          */
 681         chan = shmp(handle, handle->chan);
 682         /* chan is object 0. This is hardcoded. */
 683         chan_size = handle->table->objects[0].allocated_len;
 684         handle->shadow_chan = malloc(chan_size);
 685         if (!handle->shadow_chan) {
 686                 channel_destroy(chan, handle, 1);
 687                 return NULL;
 688         }
 689         memcpy(handle->shadow_chan, chan, chan_size);
 690         /*
 691          * The callback pointers in the producer are invalid in the
 692          * consumer. We need to look them up here.
 693          */
 694         config = &handle->shadow_chan->backend.config;
 695         switch (config->client_type) {
 696         case LTTNG_CLIENT_METADATA:
 697                 memcpy(&config->cb, lttng_client_callbacks_metadata,
 698                         sizeof(config->cb));
 699                 break;
 700         case LTTNG_CLIENT_DISCARD:
 701                 memcpy(&config->cb, lttng_client_callbacks_discard,
 702                         sizeof(config->cb));
 703                 break;
 704         case LTTNG_CLIENT_OVERWRITE:
 705                 memcpy(&config->cb, lttng_client_callbacks_overwrite,
 706                         sizeof(config->cb));
 707                 break;
 708         default:
 709                 ERR("Unknown client type %d", config->client_type);
 710                 channel_destroy(chan, handle, 1);
 711                 return NULL;
 712         }
 713         /* Replace the object table pointer. */
 714         ret = munmap(handle->table->objects[0].memory_map,
 715                 handle->table->objects[0].memory_map_size);
 716         if (ret) {
 717                 perror("munmap");
 718                 assert(0);
 719         }
 720         handle->table->objects[0].memory_map = (char *) handle->shadow_chan;
 721         handle->table->objects[0].is_shadow = 1;
 722         return handle;
 723 }
 724
 725 /* Add stream to channel shm and map its shm into process memory */
 726 int ustctl_add_stream(struct lttng_ust_shm_handle *handle,
 727                 struct lttng_ust_object_data *stream_data)
 728 {
 729         int ret;
 730
 731         if (!handle || !stream_data)
 732                 return -EINVAL;
 733
 734         if (!stream_data->handle)
 735                 return -ENOENT;
 736         /* map stream */
 737         ret = channel_handle_add_stream(handle,
 738                 stream_data->shm_fd,
 739                 stream_data->wait_fd,
 740                 stream_data->memory_map_size);
 741         if (ret) {
 742                 ERR("add stream error\n");
 743                 return ret;
 744         }
 745         /*
 746          * Set to -1 because the lttng_ust_shm_handle destruction will take care
 747          * of closing shm_fd and wait_fd.
 748          */
 749         stream_data->shm_fd = -1;
 750         stream_data->wait_fd = -1;
 751         return 0;
 752 }
 753
 754 void ustctl_unmap_channel(struct lttng_ust_shm_handle *handle)
 755 {
 756         struct channel *chan;
 757
 758         assert(handle);
 759         chan = shmp(handle, handle->chan);
 760         channel_destroy(chan, handle, 1);
 761 }
 762
 763 /*
 764  * ustctl closes the shm_fd fds after mapping it.
 765  */
 766 struct lttng_ust_lib_ring_buffer *ustctl_open_stream_read(struct lttng_ust_shm_handle *handle,
 767         int cpu)
 768 {
 769         struct channel *chan;
 770         int *shm_fd, *wait_fd;
 771         uint64_t *memory_map_size;
 772         struct lttng_ust_lib_ring_buffer *buf;
 773         int ret;
 774
 775         if (!handle)
 776                 return NULL;
 777
 778         chan = handle->shadow_chan;
 779         buf = channel_get_ring_buffer(&chan->backend.config,
 780                 chan, cpu, handle, &shm_fd, &wait_fd, &memory_map_size);
 781         if (!buf)
 782                 return NULL;
 783         ret = lib_ring_buffer_open_read(buf, handle, 1);
 784         if (ret)
 785                 return NULL;
 786         /*
 787          * We can close shm_fd early, right after is has been mapped.
 788          */
 789         if (*shm_fd >= 0) {
 790                 ret = close(*shm_fd);
 791                 if (ret) {
 792                         perror("Error closing shm_fd");
 793                 }
 794                 *shm_fd = -1;
 795         }
 796         return buf;
 797 }
 798
 799 void ustctl_close_stream_read(struct lttng_ust_shm_handle *handle,
 800                 struct lttng_ust_lib_ring_buffer *buf)
 801 {
 802         assert(handle && buf);
 803         lib_ring_buffer_release_read(buf, handle, 1);
 804 }
 805
 806 /* For mmap mode, readable without "get" operation */
 807
 808 void *ustctl_get_mmap_base(struct lttng_ust_shm_handle *handle,
 809                 struct lttng_ust_lib_ring_buffer *buf)
 810 {
 811         if (!handle || !buf)
 812                 return NULL;
 813         return shmp(handle, buf->backend.memory_map);
 814 }
 815
 816 /* returns the length to mmap. */
 817 int ustctl_get_mmap_len(struct lttng_ust_shm_handle *handle,
 818                 struct lttng_ust_lib_ring_buffer *buf,
 819                 unsigned long *len)
 820 {
 821         unsigned long mmap_buf_len;
 822         struct channel *chan;
 823
 824         if (!handle || !buf || !len)
 825                 return -EINVAL;
 826
 827         chan = handle->shadow_chan;
 828         if (chan->backend.config.output != RING_BUFFER_MMAP)
 829                 return -EINVAL;
 830         mmap_buf_len = chan->backend.buf_size;
 831         if (chan->backend.extra_reader_sb)
 832                 mmap_buf_len += chan->backend.subbuf_size;
 833         if (mmap_buf_len > INT_MAX)
 834                 return -EFBIG;
 835         *len = mmap_buf_len;
 836         return 0;
 837 }
 838
 839 /* returns the maximum size for sub-buffers. */
 840 int ustctl_get_max_subbuf_size(struct lttng_ust_shm_handle *handle,
 841                 struct lttng_ust_lib_ring_buffer *buf,
 842                 unsigned long *len)
 843 {
 844         struct channel *chan;
 845
 846         if (!handle || !buf || !len)
 847                 return -EINVAL;
 848
 849         chan = handle->shadow_chan;
 850         *len = chan->backend.subbuf_size;
 851         return 0;
 852 }
 853
 854 /*
 855  * For mmap mode, operate on the current packet (between get/put or
 856  * get_next/put_next).
 857  */
 858
 859 /* returns the offset of the subbuffer belonging to the mmap reader. */
 860 int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
 861                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 862 {
 863         struct channel *chan;
 864         unsigned long sb_bindex;
 865
 866         if (!handle || !buf || !off)
 867                 return -EINVAL;
 868
 869         chan = handle->shadow_chan;
 870         if (chan->backend.config.output != RING_BUFFER_MMAP)
 871                 return -EINVAL;
 872         sb_bindex = subbuffer_id_get_index(&chan->backend.config,
 873                                            buf->backend.buf_rsb.id);
 874         *off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
 875         return 0;
 876 }
 877
 878 /* returns the size of the current sub-buffer, without padding (for mmap). */
 879 int ustctl_get_subbuf_size(struct lttng_ust_shm_handle *handle,
 880                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 881 {
 882         struct channel *chan;
 883
 884         if (!handle || !buf || !len)
 885                 return -EINVAL;
 886
 887         chan = handle->shadow_chan;
 888         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 889                 handle);
 890         return 0;
 891 }
 892
 893 /* returns the size of the current sub-buffer, without padding (for mmap). */
 894 int ustctl_get_padded_subbuf_size(struct lttng_ust_shm_handle *handle,
 895                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *len)
 896 {
 897         struct channel *chan;
 898
 899         if (!handle || !buf || !len)
 900                 return -EINVAL;
 901
 902         chan = handle->shadow_chan;
 903         *len = lib_ring_buffer_get_read_data_size(&chan->backend.config, buf,
 904                 handle);
 905         *len = PAGE_ALIGN(*len);
 906         return 0;
 907 }
 908
 909 /* Get exclusive read access to the next sub-buffer that can be read. */
 910 int ustctl_get_next_subbuf(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_get_next_subbuf(buf, handle);
 917 }
 918
 919
 920 /* Release exclusive sub-buffer access, move consumer forward. */
 921 int ustctl_put_next_subbuf(struct lttng_ust_shm_handle *handle,
 922                 struct lttng_ust_lib_ring_buffer *buf)
 923 {
 924         if (!handle || !buf)
 925                 return -EINVAL;
 926
 927         lib_ring_buffer_put_next_subbuf(buf, handle);
 928         return 0;
 929 }
 930
 931 /* snapshot */
 932
 933 /* Get a snapshot of the current ring buffer producer and consumer positions */
 934 int ustctl_snapshot(struct lttng_ust_shm_handle *handle,
 935                 struct lttng_ust_lib_ring_buffer *buf)
 936 {
 937         if (!handle || !buf)
 938                 return -EINVAL;
 939
 940         return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
 941                         &buf->prod_snapshot, handle);
 942 }
 943
 944 /* Get the consumer position (iteration start) */
 945 int ustctl_snapshot_get_consumed(struct lttng_ust_shm_handle *handle,
 946                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 947 {
 948         if (!handle || !buf || !pos)
 949                 return -EINVAL;
 950
 951         *pos = buf->cons_snapshot;
 952         return 0;
 953 }
 954
 955 /* Get the producer position (iteration end) */
 956 int ustctl_snapshot_get_produced(struct lttng_ust_shm_handle *handle,
 957                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 958 {
 959         if (!handle || !buf || !pos)
 960                 return -EINVAL;
 961
 962         *pos = buf->prod_snapshot;
 963         return 0;
 964 }
 965
 966 /* Get exclusive read access to the specified sub-buffer position */
 967 int ustctl_get_subbuf(struct lttng_ust_shm_handle *handle,
 968                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *pos)
 969 {
 970         if (!handle || !buf || !pos)
 971                 return -EINVAL;
 972
 973         return lib_ring_buffer_get_subbuf(buf, *pos, handle);
 974 }
 975
 976 /* Release exclusive sub-buffer access */
 977 int ustctl_put_subbuf(struct lttng_ust_shm_handle *handle,
 978                 struct lttng_ust_lib_ring_buffer *buf)
 979 {
 980         if (!handle || !buf)
 981                 return -EINVAL;
 982
 983         lib_ring_buffer_put_subbuf(buf, handle);
 984         return 0;
 985 }
 986
 987 void ustctl_flush_buffer(struct lttng_ust_shm_handle *handle,
 988                 struct lttng_ust_lib_ring_buffer *buf,
 989                 int producer_active)
 990 {
 991         assert(handle && buf);
 992         lib_ring_buffer_switch_slow(buf,
 993                 producer_active ? SWITCH_ACTIVE : SWITCH_FLUSH,
 994                 handle);
 995 }