liblttng-ust/lttng-ust-abi.c

   1 /*
   2  * lttng-ust-abi.c
   3  *
   4  * Copyright 2010-2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng UST ABI
   7  *
   8  * Mimic system calls for:
   9  * - session creation, returns an object descriptor or failure.
  10  *   - channel creation, returns an object descriptor or failure.
  11  *     - Operates on a session object descriptor
  12  *     - Takes all channel options as parameters.
  13  *   - stream get, returns an object descriptor or failure.
  14  *     - Operates on a channel object descriptor.
  15  *   - stream notifier get, returns an object descriptor or failure.
  16  *     - Operates on a channel object descriptor.
  17  *   - event creation, returns an object descriptor or failure.
  18  *     - Operates on a channel object descriptor
  19  *     - Takes an event name as parameter
  20  *     - Takes an instrumentation source as parameter
  21  *       - e.g. tracepoints, dynamic_probes...
  22  *     - Takes instrumentation source specific arguments.
  23  *
  24  * Dual LGPL v2.1/GPL v2 license.
  25  */
  26
  27 #include <lttng/ust-abi.h>
  28 #include <urcu/compiler.h>
  29 #include <urcu/list.h>
  30 #include <lttng/ust-events.h>
  31 #include <lttng/ust-version.h>
  32 #include <usterr-signal-safe.h>
  33 #include <helper.h>
  34 #include "ltt-tracer.h"
  35 #include "tracepoint-internal.h"
  36
  37 static int lttng_ust_abi_close_in_progress;
  38
  39 static
  40 int lttng_abi_tracepoint_list(void);
  41
  42 /*
  43  * Object descriptor table. Should be protected from concurrent access
  44  * by the caller.
  45  */
  46
  47 struct lttng_ust_obj {
  48         union {
  49                 struct {
  50                         void *private_data;
  51                         const struct lttng_ust_objd_ops *ops;
  52                         int f_count;
  53                 } s;
  54                 int freelist_next;      /* offset freelist. end is -1. */
  55         } u;
  56 };
  57
  58 struct lttng_ust_objd_table {
  59         struct lttng_ust_obj *array;
  60         unsigned int len, allocated_len;
  61         int freelist_head;              /* offset freelist head. end is -1 */
  62 };
  63
  64 static struct lttng_ust_objd_table objd_table = {
  65         .freelist_head = -1,
  66 };
  67
  68 static
  69 int objd_alloc(void *private_data, const struct lttng_ust_objd_ops *ops)
  70 {
  71         struct lttng_ust_obj *obj;
  72
  73         if (objd_table.freelist_head != -1) {
  74                 obj = &objd_table.array[objd_table.freelist_head];
  75                 objd_table.freelist_head = obj->u.freelist_next;
  76                 goto end;
  77         }
  78
  79         if (objd_table.len >= objd_table.allocated_len) {
  80                 unsigned int new_allocated_len, old_allocated_len;
  81                 struct lttng_ust_obj *new_table, *old_table;
  82
  83                 old_allocated_len = objd_table.allocated_len;
  84                 old_table = objd_table.array;
  85                 if (!old_allocated_len)
  86                         new_allocated_len = 1;
  87                 else
  88                         new_allocated_len = old_allocated_len << 1;
  89                 new_table = zmalloc(sizeof(struct lttng_ust_obj) * new_allocated_len);
  90                 if (!new_table)
  91                         return -ENOMEM;
  92                 memcpy(new_table, old_table,
  93                        sizeof(struct lttng_ust_obj) * old_allocated_len);
  94                 free(old_table);
  95                 objd_table.array = new_table;
  96                 objd_table.allocated_len = new_allocated_len;
  97         }
  98         obj = &objd_table.array[objd_table.len];
  99         objd_table.len++;
 100 end:
 101         obj->u.s.private_data = private_data;
 102         obj->u.s.ops = ops;
 103         obj->u.s.f_count = 2;   /* count == 1 : object is allocated */
 104                                 /* count == 2 : allocated + hold ref */
 105         return obj - objd_table.array;
 106 }
 107
 108 static
 109 struct lttng_ust_obj *_objd_get(int id)
 110 {
 111         if (id >= objd_table.len)
 112                 return NULL;
 113         if (!objd_table.array[id].u.s.f_count)
 114                 return NULL;
 115         return &objd_table.array[id];
 116 }
 117
 118 static
 119 void *objd_private(int id)
 120 {
 121         struct lttng_ust_obj *obj = _objd_get(id);
 122         assert(obj);
 123         return obj->u.s.private_data;
 124 }
 125
 126 static
 127 void objd_set_private(int id, void *private_data)
 128 {
 129         struct lttng_ust_obj *obj = _objd_get(id);
 130         assert(obj);
 131         obj->u.s.private_data = private_data;
 132 }
 133
 134 const struct lttng_ust_objd_ops *objd_ops(int id)
 135 {
 136         struct lttng_ust_obj *obj = _objd_get(id);
 137
 138         if (!obj)
 139                 return NULL;
 140         return obj->u.s.ops;
 141 }
 142
 143 static
 144 void objd_free(int id)
 145 {
 146         struct lttng_ust_obj *obj = _objd_get(id);
 147
 148         assert(obj);
 149         obj->u.freelist_next = objd_table.freelist_head;
 150         objd_table.freelist_head = obj - objd_table.array;
 151         assert(obj->u.s.f_count == 1);
 152         obj->u.s.f_count = 0;   /* deallocated */
 153 }
 154
 155 static
 156 void objd_ref(int id)
 157 {
 158         struct lttng_ust_obj *obj = _objd_get(id);
 159         obj->u.s.f_count++;
 160 }
 161
 162 int lttng_ust_objd_unref(int id)
 163 {
 164         struct lttng_ust_obj *obj = _objd_get(id);
 165
 166         if (!obj)
 167                 return -EINVAL;
 168         if (obj->u.s.f_count == 1) {
 169                 ERR("Reference counting error\n");
 170                 return -EINVAL;
 171         }
 172         if ((--obj->u.s.f_count) == 1) {
 173                 const struct lttng_ust_objd_ops *ops = objd_ops(id);
 174
 175                 if (ops->release)
 176                         ops->release(id);
 177                 objd_free(id);
 178         }
 179         return 0;
 180 }
 181
 182 static
 183 void objd_table_destroy(void)
 184 {
 185         int i;
 186
 187         for (i = 0; i < objd_table.allocated_len; i++)
 188                 (void) lttng_ust_objd_unref(i);
 189         free(objd_table.array);
 190         objd_table.array = NULL;
 191         objd_table.len = 0;
 192         objd_table.allocated_len = 0;
 193         objd_table.freelist_head = -1;
 194 }
 195
 196 /*
 197  * This is LTTng's own personal way to create an ABI for sessiond.
 198  * We send commands over a socket.
 199  */
 200
 201 static const struct lttng_ust_objd_ops lttng_ops;
 202 static const struct lttng_ust_objd_ops lttng_session_ops;
 203 static const struct lttng_ust_objd_ops lttng_channel_ops;
 204 static const struct lttng_ust_objd_ops lttng_metadata_ops;
 205 static const struct lttng_ust_objd_ops lttng_event_ops;
 206 static const struct lttng_ust_objd_ops lttng_wildcard_ops;
 207 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops;
 208 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops;
 209
 210 enum channel_type {
 211         PER_CPU_CHANNEL,
 212         METADATA_CHANNEL,
 213 };
 214
 215 int lttng_abi_create_root_handle(void)
 216 {
 217         int root_handle;
 218
 219         root_handle = objd_alloc(NULL, &lttng_ops);
 220         return root_handle;
 221 }
 222
 223 static
 224 int lttng_abi_create_session(void)
 225 {
 226         struct ltt_session *session;
 227         int session_objd, ret;
 228
 229         session = ltt_session_create();
 230         if (!session)
 231                 return -ENOMEM;
 232         session_objd = objd_alloc(session, &lttng_session_ops);
 233         if (session_objd < 0) {
 234                 ret = session_objd;
 235                 goto objd_error;
 236         }
 237         session->objd = session_objd;
 238         return session_objd;
 239
 240 objd_error:
 241         ltt_session_destroy(session);
 242         return ret;
 243 }
 244
 245 static
 246 long lttng_abi_tracer_version(int objd,
 247         struct lttng_ust_tracer_version *v)
 248 {
 249         v->major = LTTNG_UST_MAJOR_VERSION;
 250         v->minor = LTTNG_UST_MINOR_VERSION;
 251         v->patchlevel = LTTNG_UST_PATCHLEVEL_VERSION;
 252         return 0;
 253 }
 254
 255 static
 256 long lttng_abi_add_context(int objd,
 257         struct lttng_ust_context *context_param,
 258         struct lttng_ctx **ctx, struct ltt_session *session)
 259 {
 260         if (session->been_active)
 261                 return -EPERM;
 262
 263         switch (context_param->ctx) {
 264         case LTTNG_UST_CONTEXT_PTHREAD_ID:
 265                 return lttng_add_pthread_id_to_ctx(ctx);
 266         case LTTNG_UST_CONTEXT_VTID:
 267                 return lttng_add_vtid_to_ctx(ctx);
 268         case LTTNG_UST_CONTEXT_VPID:
 269                 return lttng_add_vpid_to_ctx(ctx);
 270         case LTTNG_UST_CONTEXT_PROCNAME:
 271                 return lttng_add_procname_to_ctx(ctx);
 272         default:
 273                 return -EINVAL;
 274         }
 275 }
 276
 277 /**
 278  *      lttng_cmd - lttng control through socket commands
 279  *
 280  *      @objd: the object descriptor
 281  *      @cmd: the command
 282  *      @arg: command arg
 283  *      @uargs: UST arguments (internal)
 284  *
 285  *      This descriptor implements lttng commands:
 286  *      LTTNG_UST_SESSION
 287  *              Returns a LTTng trace session object descriptor
 288  *      LTTNG_UST_TRACER_VERSION
 289  *              Returns the LTTng kernel tracer version
 290  *      LTTNG_UST_TRACEPOINT_LIST
 291  *              Returns a file descriptor listing available tracepoints
 292  *      LTTNG_UST_WAIT_QUIESCENT
 293  *              Returns after all previously running probes have completed
 294  *
 295  * The returned session will be deleted when its file descriptor is closed.
 296  */
 297 static
 298 long lttng_cmd(int objd, unsigned int cmd, unsigned long arg,
 299         union ust_args *uargs)
 300 {
 301         switch (cmd) {
 302         case LTTNG_UST_SESSION:
 303                 return lttng_abi_create_session();
 304         case LTTNG_UST_TRACER_VERSION:
 305                 return lttng_abi_tracer_version(objd,
 306                                 (struct lttng_ust_tracer_version *) arg);
 307         case LTTNG_UST_TRACEPOINT_LIST:
 308                 return lttng_abi_tracepoint_list();
 309         case LTTNG_UST_WAIT_QUIESCENT:
 310                 synchronize_trace();
 311                 return 0;
 312         default:
 313                 return -EINVAL;
 314         }
 315 }
 316
 317 static const struct lttng_ust_objd_ops lttng_ops = {
 318         .cmd = lttng_cmd,
 319 };
 320
 321 /*
 322  * We tolerate no failure in this function (if one happens, we print a dmesg
 323  * error, but cannot return any error, because the channel information is
 324  * invariant.
 325  */
 326 static
 327 void lttng_metadata_create_events(int channel_objd)
 328 {
 329         struct ltt_channel *channel = objd_private(channel_objd);
 330         static struct lttng_ust_event metadata_params = {
 331                 .instrumentation = LTTNG_UST_TRACEPOINT,
 332                 .name = "lttng_ust:metadata",
 333         };
 334         struct ltt_event *event;
 335         int ret;
 336
 337         /*
 338          * We tolerate no failure path after event creation. It will stay
 339          * invariant for the rest of the session.
 340          */
 341         ret = ltt_event_create(channel, &metadata_params, NULL, &event);
 342         if (ret < 0) {
 343                 goto create_error;
 344         }
 345         return;
 346
 347 create_error:
 348         WARN_ON(1);
 349         return;         /* not allowed to return error */
 350 }
 351
 352 int lttng_abi_create_channel(int session_objd,
 353                              struct lttng_ust_channel *chan_param,
 354                              enum channel_type channel_type,
 355                              union ust_args *uargs)
 356 {
 357         struct ltt_session *session = objd_private(session_objd);
 358         const struct lttng_ust_objd_ops *ops;
 359         const char *transport_name;
 360         struct ltt_channel *chan;
 361         int chan_objd;
 362         int ret = 0;
 363         struct ltt_channel chan_priv_init;
 364
 365         switch (channel_type) {
 366         case PER_CPU_CHANNEL:
 367                 if (chan_param->output == LTTNG_UST_MMAP) {
 368                         transport_name = chan_param->overwrite ?
 369                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 370                 } else {
 371                         return -EINVAL;
 372                 }
 373                 ops = &lttng_channel_ops;
 374                 break;
 375         case METADATA_CHANNEL:
 376                 if (chan_param->output == LTTNG_UST_MMAP)
 377                         transport_name = "relay-metadata-mmap";
 378                 else
 379                         return -EINVAL;
 380                 ops = &lttng_metadata_ops;
 381                 break;
 382         default:
 383                 transport_name = "<unknown>";
 384                 return -EINVAL;
 385         }
 386         chan_objd = objd_alloc(NULL, ops);
 387         if (chan_objd < 0) {
 388                 ret = chan_objd;
 389                 goto objd_error;
 390         }
 391         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 392         /* Copy of session UUID for consumer (availability through shm) */
 393         memcpy(chan_priv_init.uuid, session->uuid, sizeof(session->uuid));
 394
 395         /*
 396          * We tolerate no failure path after channel creation. It will stay
 397          * invariant for the rest of the session.
 398          */
 399         chan = ltt_channel_create(session, transport_name, NULL,
 400                                   chan_param->subbuf_size,
 401                                   chan_param->num_subbuf,
 402                                   chan_param->switch_timer_interval,
 403                                   chan_param->read_timer_interval,
 404                                   &uargs->channel.shm_fd,
 405                                   &uargs->channel.wait_fd,
 406                                   &uargs->channel.memory_map_size,
 407                                   &chan_priv_init);
 408         if (!chan) {
 409                 ret = -EINVAL;
 410                 goto chan_error;
 411         }
 412         objd_set_private(chan_objd, chan);
 413         chan->objd = chan_objd;
 414         if (channel_type == METADATA_CHANNEL) {
 415                 session->metadata = chan;
 416                 lttng_metadata_create_events(chan_objd);
 417         }
 418         /* The channel created holds a reference on the session */
 419         objd_ref(session_objd);
 420
 421         return chan_objd;
 422
 423 chan_error:
 424         {
 425                 int err;
 426
 427                 err = lttng_ust_objd_unref(chan_objd);
 428                 assert(!err);
 429         }
 430 objd_error:
 431         return ret;
 432 }
 433
 434 /**
 435  *      lttng_session_cmd - lttng session object command
 436  *
 437  *      @obj: the object
 438  *      @cmd: the command
 439  *      @arg: command arg
 440  *      @uargs: UST arguments (internal)
 441  *
 442  *      This descriptor implements lttng commands:
 443  *      LTTNG_UST_CHANNEL
 444  *              Returns a LTTng channel object descriptor
 445  *      LTTNG_UST_ENABLE
 446  *              Enables tracing for a session (weak enable)
 447  *      LTTNG_UST_DISABLE
 448  *              Disables tracing for a session (strong disable)
 449  *      LTTNG_UST_METADATA
 450  *              Returns a LTTng metadata object descriptor
 451  *
 452  * The returned channel will be deleted when its file descriptor is closed.
 453  */
 454 static
 455 long lttng_session_cmd(int objd, unsigned int cmd, unsigned long arg,
 456         union ust_args *uargs)
 457 {
 458         struct ltt_session *session = objd_private(objd);
 459
 460         switch (cmd) {
 461         case LTTNG_UST_CHANNEL:
 462                 return lttng_abi_create_channel(objd,
 463                                 (struct lttng_ust_channel *) arg,
 464                                 PER_CPU_CHANNEL, uargs);
 465         case LTTNG_UST_SESSION_START:
 466         case LTTNG_UST_ENABLE:
 467                 return ltt_session_enable(session);
 468         case LTTNG_UST_SESSION_STOP:
 469         case LTTNG_UST_DISABLE:
 470                 return ltt_session_disable(session);
 471         case LTTNG_UST_METADATA:
 472                 return lttng_abi_create_channel(objd,
 473                                 (struct lttng_ust_channel *) arg,
 474                                 METADATA_CHANNEL, uargs);
 475         default:
 476                 return -EINVAL;
 477         }
 478 }
 479
 480 /*
 481  * Called when the last file reference is dropped.
 482  *
 483  * Big fat note: channels and events are invariant for the whole session after
 484  * their creation. So this session destruction also destroys all channel and
 485  * event structures specific to this session (they are not destroyed when their
 486  * individual file is released).
 487  */
 488 static
 489 int lttng_release_session(int objd)
 490 {
 491         struct ltt_session *session = objd_private(objd);
 492
 493         if (session) {
 494                 ltt_session_destroy(session);
 495                 return 0;
 496         } else {
 497                 return -EINVAL;
 498         }
 499 }
 500
 501 static const struct lttng_ust_objd_ops lttng_session_ops = {
 502         .release = lttng_release_session,
 503         .cmd = lttng_session_cmd,
 504 };
 505
 506 static
 507 long lttng_tracepoint_list_cmd(int objd, unsigned int cmd, unsigned long arg,
 508         union ust_args *uargs)
 509 {
 510         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 511         struct lttng_ust_tracepoint_iter *tp =
 512                 (struct lttng_ust_tracepoint_iter *) arg;
 513         struct lttng_ust_tracepoint_iter *iter;
 514
 515         switch (cmd) {
 516         case LTTNG_UST_TRACEPOINT_LIST_GET:
 517         {
 518         retry:
 519                 iter = lttng_ust_tracepoint_list_get_iter_next(list);
 520                 if (!iter)
 521                         return -ENOENT;
 522                 if (!strcmp(iter->name, "lttng_ust:metadata"))
 523                         goto retry;
 524                 memcpy(tp, iter, sizeof(*tp));
 525                 return 0;
 526         }
 527         default:
 528                 return -EINVAL;
 529         }
 530 }
 531
 532 static
 533 int lttng_abi_tracepoint_list(void)
 534 {
 535         int list_objd, ret;
 536         struct lttng_ust_tracepoint_list *list;
 537
 538         list_objd = objd_alloc(NULL, &lttng_tracepoint_list_ops);
 539         if (list_objd < 0) {
 540                 ret = list_objd;
 541                 goto objd_error;
 542         }
 543         list = zmalloc(sizeof(*list));
 544         if (!list) {
 545                 ret = -ENOMEM;
 546                 goto alloc_error;
 547         }
 548         objd_set_private(list_objd, list);
 549
 550         /* populate list by walking on all registered probes. */
 551         ret = ltt_probes_get_event_list(list);
 552         if (ret) {
 553                 goto list_error;
 554         }
 555         return list_objd;
 556
 557 list_error:
 558         free(list);
 559 alloc_error:
 560         {
 561                 int err;
 562
 563                 err = lttng_ust_objd_unref(list_objd);
 564                 assert(!err);
 565         }
 566 objd_error:
 567         return ret;
 568 }
 569
 570 static
 571 int lttng_release_tracepoint_list(int objd)
 572 {
 573         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 574
 575         if (list) {
 576                 ltt_probes_prune_event_list(list);
 577                 free(list);
 578                 return 0;
 579         } else {
 580                 return -EINVAL;
 581         }
 582 }
 583
 584 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops = {
 585         .release = lttng_release_tracepoint_list,
 586         .cmd = lttng_tracepoint_list_cmd,
 587 };
 588
 589 struct stream_priv_data {
 590         struct lttng_ust_lib_ring_buffer *buf;
 591         struct ltt_channel *ltt_chan;
 592 };
 593
 594 static
 595 int lttng_abi_open_stream(int channel_objd, struct lttng_ust_stream *info,
 596                 union ust_args *uargs)
 597 {
 598         struct ltt_channel *channel = objd_private(channel_objd);
 599         struct lttng_ust_lib_ring_buffer *buf;
 600         struct stream_priv_data *priv;
 601         int stream_objd, ret;
 602
 603         buf = channel->ops->buffer_read_open(channel->chan, channel->handle,
 604                         &uargs->stream.shm_fd,
 605                         &uargs->stream.wait_fd,
 606                         &uargs->stream.memory_map_size);
 607         if (!buf)
 608                 return -ENOENT;
 609
 610         priv = zmalloc(sizeof(*priv));
 611         if (!priv) {
 612                 ret = -ENOMEM;
 613                 goto alloc_error;
 614         }
 615         priv->buf = buf;
 616         priv->ltt_chan = channel;
 617         stream_objd = objd_alloc(priv, &lib_ring_buffer_objd_ops);
 618         if (stream_objd < 0) {
 619                 ret = stream_objd;
 620                 goto objd_error;
 621         }
 622         /* Hold a reference on the channel object descriptor */
 623         objd_ref(channel_objd);
 624         return stream_objd;
 625
 626 objd_error:
 627         free(priv);
 628 alloc_error:
 629         channel->ops->buffer_read_close(buf, channel->handle);
 630         return ret;
 631 }
 632
 633 static
 634 int lttng_abi_create_event(int channel_objd,
 635                            struct lttng_ust_event *event_param)
 636 {
 637         struct ltt_channel *channel = objd_private(channel_objd);
 638         struct ltt_event *event;
 639         int event_objd, ret;
 640
 641         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 642         event_objd = objd_alloc(NULL, &lttng_event_ops);
 643         if (event_objd < 0) {
 644                 ret = event_objd;
 645                 goto objd_error;
 646         }
 647         /*
 648          * We tolerate no failure path after event creation. It will stay
 649          * invariant for the rest of the session.
 650          */
 651         ret = ltt_event_create(channel, event_param, NULL, &event);
 652         if (ret < 0) {
 653                 goto event_error;
 654         }
 655         objd_set_private(event_objd, event);
 656         /* The event holds a reference on the channel */
 657         objd_ref(channel_objd);
 658         return event_objd;
 659
 660 event_error:
 661         {
 662                 int err;
 663
 664                 err = lttng_ust_objd_unref(event_objd);
 665                 assert(!err);
 666         }
 667 objd_error:
 668         return ret;
 669 }
 670
 671 static
 672 int lttng_abi_create_wildcard(int channel_objd,
 673                               struct lttng_ust_event *event_param)
 674 {
 675         struct ltt_channel *channel = objd_private(channel_objd);
 676         struct session_wildcard *wildcard;
 677         int wildcard_objd, ret;
 678
 679         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 680         wildcard_objd = objd_alloc(NULL, &lttng_wildcard_ops);
 681         if (wildcard_objd < 0) {
 682                 ret = wildcard_objd;
 683                 goto objd_error;
 684         }
 685         /*
 686          * We tolerate no failure path after wildcard creation. It will
 687          * stay invariant for the rest of the session.
 688          */
 689         ret = ltt_wildcard_create(channel, event_param, &wildcard);
 690         if (ret < 0) {
 691                 goto wildcard_error;
 692         }
 693         objd_set_private(wildcard_objd, wildcard);
 694         /* The wildcard holds a reference on the channel */
 695         objd_ref(channel_objd);
 696         return wildcard_objd;
 697
 698 wildcard_error:
 699         {
 700                 int err;
 701
 702                 err = lttng_ust_objd_unref(wildcard_objd);
 703                 assert(!err);
 704         }
 705 objd_error:
 706         return ret;
 707 }
 708
 709 /**
 710  *      lttng_channel_cmd - lttng control through object descriptors
 711  *
 712  *      @objd: the object descriptor
 713  *      @cmd: the command
 714  *      @arg: command arg
 715  *      @uargs: UST arguments (internal)
 716  *
 717  *      This object descriptor implements lttng commands:
 718  *      LTTNG_UST_STREAM
 719  *              Returns an event stream object descriptor or failure.
 720  *              (typically, one event stream records events from one CPU)
 721  *      LTTNG_UST_EVENT
 722  *              Returns an event object descriptor or failure.
 723  *      LTTNG_UST_CONTEXT
 724  *              Prepend a context field to each event in the channel
 725  *      LTTNG_UST_ENABLE
 726  *              Enable recording for events in this channel (weak enable)
 727  *      LTTNG_UST_DISABLE
 728  *              Disable recording for events in this channel (strong disable)
 729  *
 730  * Channel and event file descriptors also hold a reference on the session.
 731  */
 732 static
 733 long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg,
 734         union ust_args *uargs)
 735 {
 736         struct ltt_channel *channel = objd_private(objd);
 737
 738         switch (cmd) {
 739         case LTTNG_UST_STREAM:
 740         {
 741                 struct lttng_ust_stream *stream;
 742
 743                 stream = (struct lttng_ust_stream *) arg;
 744                 /* stream used as output */
 745                 return lttng_abi_open_stream(objd, stream, uargs);
 746         }
 747         case LTTNG_UST_EVENT:
 748         {
 749                 struct lttng_ust_event *event_param =
 750                         (struct lttng_ust_event *) arg;
 751                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
 752                         /* If ends with wildcard, create wildcard. */
 753                         return lttng_abi_create_wildcard(objd, event_param);
 754                 } else {
 755                         return lttng_abi_create_event(objd, event_param);
 756                 }
 757         }
 758         case LTTNG_UST_CONTEXT:
 759                 return lttng_abi_add_context(objd,
 760                                 (struct lttng_ust_context *) arg,
 761                                 &channel->ctx, channel->session);
 762         case LTTNG_UST_ENABLE:
 763                 return ltt_channel_enable(channel);
 764         case LTTNG_UST_DISABLE:
 765                 return ltt_channel_disable(channel);
 766         case LTTNG_UST_FLUSH_BUFFER:
 767                 return channel->ops->flush_buffer(channel->chan, channel->handle);
 768         default:
 769                 return -EINVAL;
 770         }
 771 }
 772
 773 /**
 774  *      lttng_metadata_cmd - lttng control through object descriptors
 775  *
 776  *      @objd: the object descriptor
 777  *      @cmd: the command
 778  *      @arg: command arg
 779  *      @uargs: UST arguments (internal)
 780  *
 781  *      This object descriptor implements lttng commands:
 782  *      LTTNG_UST_STREAM
 783  *              Returns an event stream file descriptor or failure.
 784  *
 785  * Channel and event file descriptors also hold a reference on the session.
 786  */
 787 static
 788 long lttng_metadata_cmd(int objd, unsigned int cmd, unsigned long arg,
 789         union ust_args *uargs)
 790 {
 791         struct ltt_channel *channel = objd_private(objd);
 792
 793         switch (cmd) {
 794         case LTTNG_UST_STREAM:
 795         {
 796                 struct lttng_ust_stream *stream;
 797
 798                 stream = (struct lttng_ust_stream *) arg;
 799                 /* stream used as output */
 800                 return lttng_abi_open_stream(objd, stream, uargs);
 801         }
 802         case LTTNG_UST_FLUSH_BUFFER:
 803                 return channel->ops->flush_buffer(channel->chan, channel->handle);
 804         default:
 805                 return -EINVAL;
 806         }
 807 }
 808
 809 #if 0
 810 /**
 811  *      lttng_channel_poll - lttng stream addition/removal monitoring
 812  *
 813  *      @file: the file
 814  *      @wait: poll table
 815  */
 816 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
 817 {
 818         struct ltt_channel *channel = file->private_data;
 819         unsigned int mask = 0;
 820
 821         if (file->f_mode & FMODE_READ) {
 822                 poll_wait_set_exclusive(wait);
 823                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
 824                           wait);
 825
 826                 if (channel->ops->is_disabled(channel->chan))
 827                         return POLLERR;
 828                 if (channel->ops->is_finalized(channel->chan))
 829                         return POLLHUP;
 830                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
 831                         return POLLIN | POLLRDNORM;
 832                 return 0;
 833         }
 834         return mask;
 835
 836 }
 837 #endif //0
 838
 839 static
 840 int lttng_channel_release(int objd)
 841 {
 842         struct ltt_channel *channel = objd_private(objd);
 843
 844         if (channel)
 845                 return lttng_ust_objd_unref(channel->session->objd);
 846         return 0;
 847 }
 848
 849 static const struct lttng_ust_objd_ops lttng_channel_ops = {
 850         .release = lttng_channel_release,
 851         //.poll = lttng_channel_poll,
 852         .cmd = lttng_channel_cmd,
 853 };
 854
 855 static const struct lttng_ust_objd_ops lttng_metadata_ops = {
 856         .release = lttng_channel_release,
 857         .cmd = lttng_metadata_cmd,
 858 };
 859
 860 /**
 861  *      lttng_rb_cmd - lttng ring buffer control through object descriptors
 862  *
 863  *      @objd: the object descriptor
 864  *      @cmd: the command
 865  *      @arg: command arg
 866  *      @uargs: UST arguments (internal)
 867  *
 868  *      This object descriptor implements lttng commands:
 869  *              (None for now. Access is done directly though shm.)
 870  */
 871 static
 872 long lttng_rb_cmd(int objd, unsigned int cmd, unsigned long arg,
 873         union ust_args *uargs)
 874 {
 875         switch (cmd) {
 876         default:
 877                 return -EINVAL;
 878         }
 879 }
 880
 881 static
 882 int lttng_rb_release(int objd)
 883 {
 884         struct stream_priv_data *priv = objd_private(objd);
 885         struct lttng_ust_lib_ring_buffer *buf;
 886         struct ltt_channel *channel;
 887
 888         if (priv) {
 889                 buf = priv->buf;
 890                 channel = priv->ltt_chan;
 891                 free(priv);
 892                 /*
 893                  * If we are at ABI exit, we don't want to close the
 894                  * buffer opened for read: it is being shared between
 895                  * the parent and child (right after fork), and we don't
 896                  * want the child to close it for the parent. For a real
 897                  * exit, we don't care about marking it as closed, as
 898                  * the consumer daemon (if there is one) will do fine
 899                  * even if we don't mark it as "closed" for reading on
 900                  * our side.
 901                  * We only mark it as closed if it is being explicitely
 902                  * released by the session daemon with an explicit
 903                  * release command.
 904                  */
 905                 if (!lttng_ust_abi_close_in_progress)
 906                         channel->ops->buffer_read_close(buf, channel->handle);
 907
 908                 return lttng_ust_objd_unref(channel->objd);
 909         }
 910         return 0;
 911 }
 912
 913 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops = {
 914         .release = lttng_rb_release,
 915         .cmd = lttng_rb_cmd,
 916 };
 917
 918 /**
 919  *      lttng_event_cmd - lttng control through object descriptors
 920  *
 921  *      @objd: the object descriptor
 922  *      @cmd: the command
 923  *      @arg: command arg
 924  *      @uargs: UST arguments (internal)
 925  *
 926  *      This object descriptor implements lttng commands:
 927  *      LTTNG_UST_CONTEXT
 928  *              Prepend a context field to each record of this event
 929  *      LTTNG_UST_ENABLE
 930  *              Enable recording for this event (weak enable)
 931  *      LTTNG_UST_DISABLE
 932  *              Disable recording for this event (strong disable)
 933  */
 934 static
 935 long lttng_event_cmd(int objd, unsigned int cmd, unsigned long arg,
 936         union ust_args *uargs)
 937 {
 938         struct ltt_event *event = objd_private(objd);
 939
 940         switch (cmd) {
 941         case LTTNG_UST_CONTEXT:
 942                 return lttng_abi_add_context(objd,
 943                                 (struct lttng_ust_context *) arg,
 944                                 &event->ctx, event->chan->session);
 945         case LTTNG_UST_ENABLE:
 946                 return ltt_event_enable(event);
 947         case LTTNG_UST_DISABLE:
 948                 return ltt_event_disable(event);
 949         default:
 950                 return -EINVAL;
 951         }
 952 }
 953
 954 static
 955 int lttng_event_release(int objd)
 956 {
 957         struct ltt_event *event = objd_private(objd);
 958
 959         if (event)
 960                 return lttng_ust_objd_unref(event->chan->objd);
 961         return 0;
 962 }
 963
 964 /* TODO: filter control ioctl */
 965 static const struct lttng_ust_objd_ops lttng_event_ops = {
 966         .release = lttng_event_release,
 967         .cmd = lttng_event_cmd,
 968 };
 969
 970 /**
 971  *      lttng_wildcard_cmd - lttng control through object descriptors
 972  *
 973  *      @objd: the object descriptor
 974  *      @cmd: the command
 975  *      @arg: command arg
 976  *      @uargs: UST arguments (internal)
 977  *
 978  *      This object descriptor implements lttng commands:
 979  *      LTTNG_UST_CONTEXT
 980  *              Prepend a context field to each record of events of this
 981  *              wildcard.
 982  *      LTTNG_UST_ENABLE
 983  *              Enable recording for these wildcard events (weak enable)
 984  *      LTTNG_UST_DISABLE
 985  *              Disable recording for these wildcard events (strong disable)
 986  */
 987 static
 988 long lttng_wildcard_cmd(int objd, unsigned int cmd, unsigned long arg,
 989         union ust_args *uargs)
 990 {
 991         struct session_wildcard *wildcard = objd_private(objd);
 992
 993         switch (cmd) {
 994         case LTTNG_UST_CONTEXT:
 995                 return -ENOSYS; /* not implemented yet */
 996 #if 0
 997                 return lttng_abi_add_context(objd,
 998                                 (struct lttng_ust_context *) arg,
 999                                 &wildcard->ctx, wildcard->chan->session);
1000 #endif
1001         case LTTNG_UST_ENABLE:
1002                 return ltt_wildcard_enable(wildcard);
1003         case LTTNG_UST_DISABLE:
1004                 return ltt_wildcard_disable(wildcard);
1005         default:
1006                 return -EINVAL;
1007         }
1008 }
1009
1010 static
1011 int lttng_wildcard_release(int objd)
1012 {
1013         struct session_wildcard *wildcard = objd_private(objd);
1014
1015         if (wildcard)
1016                 return lttng_ust_objd_unref(wildcard->chan->objd);
1017         return 0;
1018 }
1019
1020 /* TODO: filter control ioctl */
1021 static const struct lttng_ust_objd_ops lttng_wildcard_ops = {
1022         .release = lttng_wildcard_release,
1023         .cmd = lttng_wildcard_cmd,
1024 };
1025
1026 void lttng_ust_abi_exit(void)
1027 {
1028         lttng_ust_abi_close_in_progress = 1;
1029         objd_table_destroy();
1030         lttng_ust_abi_close_in_progress = 0;
1031 }