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