liblttng-ust/lttng-ust-abi.c

   1 /*
   2  * lttng-ust-abi.c
   3  *
   4  * LTTng UST ABI
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  *
  23  * Mimic system calls for:
  24  * - session creation, returns an object descriptor or failure.
  25  *   - channel creation, returns an object descriptor or failure.
  26  *     - Operates on a session object descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns an object descriptor or failure.
  29  *     - Operates on a channel object descriptor.
  30  *   - stream notifier get, returns an object descriptor or failure.
  31  *     - Operates on a channel object descriptor.
  32  *   - event creation, returns an object descriptor or failure.
  33  *     - Operates on a channel object descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #include <lttng/ust-abi.h>
  41 #include <urcu/compiler.h>
  42 #include <urcu/list.h>
  43 #include <lttng/ust-events.h>
  44 #include <lttng/ust-version.h>
  45 #include <lttng/tracepoint.h>
  46 #include "tracepoint-internal.h"
  47 #include <usterr-signal-safe.h>
  48 #include <helper.h>
  49 #include "ltt-tracer.h"
  50
  51 static int lttng_ust_abi_close_in_progress;
  52
  53 static
  54 int lttng_abi_tracepoint_list(void);
  55
  56 /*
  57  * Object descriptor table. Should be protected from concurrent access
  58  * by the caller.
  59  */
  60
  61 struct lttng_ust_obj {
  62         union {
  63                 struct {
  64                         void *private_data;
  65                         const struct lttng_ust_objd_ops *ops;
  66                         int f_count;
  67                 } s;
  68                 int freelist_next;      /* offset freelist. end is -1. */
  69         } u;
  70 };
  71
  72 struct lttng_ust_objd_table {
  73         struct lttng_ust_obj *array;
  74         unsigned int len, allocated_len;
  75         int freelist_head;              /* offset freelist head. end is -1 */
  76 };
  77
  78 static struct lttng_ust_objd_table objd_table = {
  79         .freelist_head = -1,
  80 };
  81
  82 static
  83 int objd_alloc(void *private_data, const struct lttng_ust_objd_ops *ops)
  84 {
  85         struct lttng_ust_obj *obj;
  86
  87         if (objd_table.freelist_head != -1) {
  88                 obj = &objd_table.array[objd_table.freelist_head];
  89                 objd_table.freelist_head = obj->u.freelist_next;
  90                 goto end;
  91         }
  92
  93         if (objd_table.len >= objd_table.allocated_len) {
  94                 unsigned int new_allocated_len, old_allocated_len;
  95                 struct lttng_ust_obj *new_table, *old_table;
  96
  97                 old_allocated_len = objd_table.allocated_len;
  98                 old_table = objd_table.array;
  99                 if (!old_allocated_len)
 100                         new_allocated_len = 1;
 101                 else
 102                         new_allocated_len = old_allocated_len << 1;
 103                 new_table = zmalloc(sizeof(struct lttng_ust_obj) * new_allocated_len);
 104                 if (!new_table)
 105                         return -ENOMEM;
 106                 memcpy(new_table, old_table,
 107                        sizeof(struct lttng_ust_obj) * old_allocated_len);
 108                 free(old_table);
 109                 objd_table.array = new_table;
 110                 objd_table.allocated_len = new_allocated_len;
 111         }
 112         obj = &objd_table.array[objd_table.len];
 113         objd_table.len++;
 114 end:
 115         obj->u.s.private_data = private_data;
 116         obj->u.s.ops = ops;
 117         obj->u.s.f_count = 2;   /* count == 1 : object is allocated */
 118                                 /* count == 2 : allocated + hold ref */
 119         return obj - objd_table.array;
 120 }
 121
 122 static
 123 struct lttng_ust_obj *_objd_get(int id)
 124 {
 125         if (id >= objd_table.len)
 126                 return NULL;
 127         if (!objd_table.array[id].u.s.f_count)
 128                 return NULL;
 129         return &objd_table.array[id];
 130 }
 131
 132 static
 133 void *objd_private(int id)
 134 {
 135         struct lttng_ust_obj *obj = _objd_get(id);
 136         assert(obj);
 137         return obj->u.s.private_data;
 138 }
 139
 140 static
 141 void objd_set_private(int id, void *private_data)
 142 {
 143         struct lttng_ust_obj *obj = _objd_get(id);
 144         assert(obj);
 145         obj->u.s.private_data = private_data;
 146 }
 147
 148 const struct lttng_ust_objd_ops *objd_ops(int id)
 149 {
 150         struct lttng_ust_obj *obj = _objd_get(id);
 151
 152         if (!obj)
 153                 return NULL;
 154         return obj->u.s.ops;
 155 }
 156
 157 static
 158 void objd_free(int id)
 159 {
 160         struct lttng_ust_obj *obj = _objd_get(id);
 161
 162         assert(obj);
 163         obj->u.freelist_next = objd_table.freelist_head;
 164         objd_table.freelist_head = obj - objd_table.array;
 165         assert(obj->u.s.f_count == 1);
 166         obj->u.s.f_count = 0;   /* deallocated */
 167 }
 168
 169 static
 170 void objd_ref(int id)
 171 {
 172         struct lttng_ust_obj *obj = _objd_get(id);
 173         obj->u.s.f_count++;
 174 }
 175
 176 int lttng_ust_objd_unref(int id)
 177 {
 178         struct lttng_ust_obj *obj = _objd_get(id);
 179
 180         if (!obj)
 181                 return -EINVAL;
 182         if (obj->u.s.f_count == 1) {
 183                 ERR("Reference counting error\n");
 184                 return -EINVAL;
 185         }
 186         if ((--obj->u.s.f_count) == 1) {
 187                 const struct lttng_ust_objd_ops *ops = objd_ops(id);
 188
 189                 if (ops->release)
 190                         ops->release(id);
 191                 objd_free(id);
 192         }
 193         return 0;
 194 }
 195
 196 static
 197 void objd_table_destroy(void)
 198 {
 199         int i;
 200
 201         for (i = 0; i < objd_table.allocated_len; i++)
 202                 (void) lttng_ust_objd_unref(i);
 203         free(objd_table.array);
 204         objd_table.array = NULL;
 205         objd_table.len = 0;
 206         objd_table.allocated_len = 0;
 207         objd_table.freelist_head = -1;
 208 }
 209
 210 /*
 211  * This is LTTng's own personal way to create an ABI for sessiond.
 212  * We send commands over a socket.
 213  */
 214
 215 static const struct lttng_ust_objd_ops lttng_ops;
 216 static const struct lttng_ust_objd_ops lttng_session_ops;
 217 static const struct lttng_ust_objd_ops lttng_channel_ops;
 218 static const struct lttng_ust_objd_ops lttng_metadata_ops;
 219 static const struct lttng_ust_objd_ops lttng_event_ops;
 220 static const struct lttng_ust_objd_ops lttng_wildcard_ops;
 221 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops;
 222 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops;
 223
 224 enum channel_type {
 225         PER_CPU_CHANNEL,
 226         METADATA_CHANNEL,
 227 };
 228
 229 int lttng_abi_create_root_handle(void)
 230 {
 231         int root_handle;
 232
 233         root_handle = objd_alloc(NULL, &lttng_ops);
 234         return root_handle;
 235 }
 236
 237 static
 238 int lttng_abi_create_session(void)
 239 {
 240         struct ltt_session *session;
 241         int session_objd, ret;
 242
 243         session = ltt_session_create();
 244         if (!session)
 245                 return -ENOMEM;
 246         session_objd = objd_alloc(session, &lttng_session_ops);
 247         if (session_objd < 0) {
 248                 ret = session_objd;
 249                 goto objd_error;
 250         }
 251         session->objd = session_objd;
 252         return session_objd;
 253
 254 objd_error:
 255         ltt_session_destroy(session);
 256         return ret;
 257 }
 258
 259 static
 260 long lttng_abi_tracer_version(int objd,
 261         struct lttng_ust_tracer_version *v)
 262 {
 263         v->major = LTTNG_UST_MAJOR_VERSION;
 264         v->minor = LTTNG_UST_MINOR_VERSION;
 265         v->patchlevel = LTTNG_UST_PATCHLEVEL_VERSION;
 266         return 0;
 267 }
 268
 269 static
 270 long lttng_abi_add_context(int objd,
 271         struct lttng_ust_context *context_param,
 272         struct lttng_ctx **ctx, struct ltt_session *session)
 273 {
 274         if (session->been_active)
 275                 return -EPERM;
 276
 277         switch (context_param->ctx) {
 278         case LTTNG_UST_CONTEXT_PTHREAD_ID:
 279                 return lttng_add_pthread_id_to_ctx(ctx);
 280         case LTTNG_UST_CONTEXT_VTID:
 281                 return lttng_add_vtid_to_ctx(ctx);
 282         case LTTNG_UST_CONTEXT_VPID:
 283                 return lttng_add_vpid_to_ctx(ctx);
 284         case LTTNG_UST_CONTEXT_PROCNAME:
 285                 return lttng_add_procname_to_ctx(ctx);
 286         default:
 287                 return -EINVAL;
 288         }
 289 }
 290
 291 /**
 292  *      lttng_cmd - lttng control through socket commands
 293  *
 294  *      @objd: the object descriptor
 295  *      @cmd: the command
 296  *      @arg: command arg
 297  *      @uargs: UST arguments (internal)
 298  *
 299  *      This descriptor implements lttng commands:
 300  *      LTTNG_UST_SESSION
 301  *              Returns a LTTng trace session object descriptor
 302  *      LTTNG_UST_TRACER_VERSION
 303  *              Returns the LTTng kernel tracer version
 304  *      LTTNG_UST_TRACEPOINT_LIST
 305  *              Returns a file descriptor listing available tracepoints
 306  *      LTTNG_UST_WAIT_QUIESCENT
 307  *              Returns after all previously running probes have completed
 308  *
 309  * The returned session will be deleted when its file descriptor is closed.
 310  */
 311 static
 312 long lttng_cmd(int objd, unsigned int cmd, unsigned long arg,
 313         union ust_args *uargs)
 314 {
 315         switch (cmd) {
 316         case LTTNG_UST_SESSION:
 317                 return lttng_abi_create_session();
 318         case LTTNG_UST_TRACER_VERSION:
 319                 return lttng_abi_tracer_version(objd,
 320                                 (struct lttng_ust_tracer_version *) arg);
 321         case LTTNG_UST_TRACEPOINT_LIST:
 322                 return lttng_abi_tracepoint_list();
 323         case LTTNG_UST_WAIT_QUIESCENT:
 324                 synchronize_trace();
 325                 return 0;
 326         default:
 327                 return -EINVAL;
 328         }
 329 }
 330
 331 static const struct lttng_ust_objd_ops lttng_ops = {
 332         .cmd = lttng_cmd,
 333 };
 334
 335 /*
 336  * We tolerate no failure in this function (if one happens, we print a dmesg
 337  * error, but cannot return any error, because the channel information is
 338  * invariant.
 339  */
 340 static
 341 void lttng_metadata_create_events(int channel_objd)
 342 {
 343         struct ltt_channel *channel = objd_private(channel_objd);
 344         static struct lttng_ust_event metadata_params = {
 345                 .instrumentation = LTTNG_UST_TRACEPOINT,
 346                 .name = "lttng_ust:metadata",
 347                 .loglevel_type = LTTNG_UST_LOGLEVEL_ALL,
 348                 .loglevel = TRACE_DEFAULT,
 349         };
 350         struct ltt_event *event;
 351         int ret;
 352
 353         /*
 354          * We tolerate no failure path after event creation. It will stay
 355          * invariant for the rest of the session.
 356          */
 357         ret = ltt_event_create(channel, &metadata_params, NULL, &event);
 358         if (ret < 0) {
 359                 goto create_error;
 360         }
 361         return;
 362
 363 create_error:
 364         WARN_ON(1);
 365         return;         /* not allowed to return error */
 366 }
 367
 368 int lttng_abi_create_channel(int session_objd,
 369                              struct lttng_ust_channel *chan_param,
 370                              enum channel_type channel_type,
 371                              union ust_args *uargs)
 372 {
 373         struct ltt_session *session = objd_private(session_objd);
 374         const struct lttng_ust_objd_ops *ops;
 375         const char *transport_name;
 376         struct ltt_channel *chan;
 377         int chan_objd;
 378         int ret = 0;
 379         struct ltt_channel chan_priv_init;
 380
 381         switch (channel_type) {
 382         case PER_CPU_CHANNEL:
 383                 if (chan_param->output == LTTNG_UST_MMAP) {
 384                         transport_name = chan_param->overwrite ?
 385                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 386                 } else {
 387                         return -EINVAL;
 388                 }
 389                 ops = &lttng_channel_ops;
 390                 break;
 391         case METADATA_CHANNEL:
 392                 if (chan_param->output == LTTNG_UST_MMAP)
 393                         transport_name = "relay-metadata-mmap";
 394                 else
 395                         return -EINVAL;
 396                 ops = &lttng_metadata_ops;
 397                 break;
 398         default:
 399                 transport_name = "<unknown>";
 400                 return -EINVAL;
 401         }
 402         chan_objd = objd_alloc(NULL, ops);
 403         if (chan_objd < 0) {
 404                 ret = chan_objd;
 405                 goto objd_error;
 406         }
 407         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 408         /* Copy of session UUID for consumer (availability through shm) */
 409         memcpy(chan_priv_init.uuid, session->uuid, sizeof(session->uuid));
 410
 411         /*
 412          * We tolerate no failure path after channel creation. It will stay
 413          * invariant for the rest of the session.
 414          */
 415         chan = ltt_channel_create(session, transport_name, NULL,
 416                                   chan_param->subbuf_size,
 417                                   chan_param->num_subbuf,
 418                                   chan_param->switch_timer_interval,
 419                                   chan_param->read_timer_interval,
 420                                   &uargs->channel.shm_fd,
 421                                   &uargs->channel.shm_path,
 422                                   &uargs->channel.wait_fd,
 423                                   &uargs->channel.wait_pipe_path,
 424                                   &uargs->channel.memory_map_size,
 425                                   &chan_priv_init);
 426         if (!chan) {
 427                 ret = -EINVAL;
 428                 goto chan_error;
 429         }
 430         objd_set_private(chan_objd, chan);
 431         chan->objd = chan_objd;
 432         if (channel_type == METADATA_CHANNEL) {
 433                 session->metadata = chan;
 434                 lttng_metadata_create_events(chan_objd);
 435         }
 436         /* The channel created holds a reference on the session */
 437         objd_ref(session_objd);
 438
 439         return chan_objd;
 440
 441 chan_error:
 442         {
 443                 int err;
 444
 445                 err = lttng_ust_objd_unref(chan_objd);
 446                 assert(!err);
 447         }
 448 objd_error:
 449         return ret;
 450 }
 451
 452 /**
 453  *      lttng_session_cmd - lttng session object command
 454  *
 455  *      @obj: the object
 456  *      @cmd: the command
 457  *      @arg: command arg
 458  *      @uargs: UST arguments (internal)
 459  *
 460  *      This descriptor implements lttng commands:
 461  *      LTTNG_UST_CHANNEL
 462  *              Returns a LTTng channel object descriptor
 463  *      LTTNG_UST_ENABLE
 464  *              Enables tracing for a session (weak enable)
 465  *      LTTNG_UST_DISABLE
 466  *              Disables tracing for a session (strong disable)
 467  *      LTTNG_UST_METADATA
 468  *              Returns a LTTng metadata object descriptor
 469  *
 470  * The returned channel will be deleted when its file descriptor is closed.
 471  */
 472 static
 473 long lttng_session_cmd(int objd, unsigned int cmd, unsigned long arg,
 474         union ust_args *uargs)
 475 {
 476         struct ltt_session *session = objd_private(objd);
 477
 478         switch (cmd) {
 479         case LTTNG_UST_CHANNEL:
 480                 return lttng_abi_create_channel(objd,
 481                                 (struct lttng_ust_channel *) arg,
 482                                 PER_CPU_CHANNEL, uargs);
 483         case LTTNG_UST_SESSION_START:
 484         case LTTNG_UST_ENABLE:
 485                 return ltt_session_enable(session);
 486         case LTTNG_UST_SESSION_STOP:
 487         case LTTNG_UST_DISABLE:
 488                 return ltt_session_disable(session);
 489         case LTTNG_UST_METADATA:
 490                 return lttng_abi_create_channel(objd,
 491                                 (struct lttng_ust_channel *) arg,
 492                                 METADATA_CHANNEL, uargs);
 493         default:
 494                 return -EINVAL;
 495         }
 496 }
 497
 498 /*
 499  * Called when the last file reference is dropped.
 500  *
 501  * Big fat note: channels and events are invariant for the whole session after
 502  * their creation. So this session destruction also destroys all channel and
 503  * event structures specific to this session (they are not destroyed when their
 504  * individual file is released).
 505  */
 506 static
 507 int lttng_release_session(int objd)
 508 {
 509         struct ltt_session *session = objd_private(objd);
 510
 511         if (session) {
 512                 ltt_session_destroy(session);
 513                 return 0;
 514         } else {
 515                 return -EINVAL;
 516         }
 517 }
 518
 519 static const struct lttng_ust_objd_ops lttng_session_ops = {
 520         .release = lttng_release_session,
 521         .cmd = lttng_session_cmd,
 522 };
 523
 524 static
 525 long lttng_tracepoint_list_cmd(int objd, unsigned int cmd, unsigned long arg,
 526         union ust_args *uargs)
 527 {
 528         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 529         struct lttng_ust_tracepoint_iter *tp =
 530                 (struct lttng_ust_tracepoint_iter *) arg;
 531         struct lttng_ust_tracepoint_iter *iter;
 532
 533         switch (cmd) {
 534         case LTTNG_UST_TRACEPOINT_LIST_GET:
 535         {
 536         retry:
 537                 iter = lttng_ust_tracepoint_list_get_iter_next(list);
 538                 if (!iter)
 539                         return -ENOENT;
 540                 if (!strcmp(iter->name, "lttng_ust:metadata"))
 541                         goto retry;
 542                 memcpy(tp, iter, sizeof(*tp));
 543                 return 0;
 544         }
 545         default:
 546                 return -EINVAL;
 547         }
 548 }
 549
 550 static
 551 int lttng_abi_tracepoint_list(void)
 552 {
 553         int list_objd, ret;
 554         struct lttng_ust_tracepoint_list *list;
 555
 556         list_objd = objd_alloc(NULL, &lttng_tracepoint_list_ops);
 557         if (list_objd < 0) {
 558                 ret = list_objd;
 559                 goto objd_error;
 560         }
 561         list = zmalloc(sizeof(*list));
 562         if (!list) {
 563                 ret = -ENOMEM;
 564                 goto alloc_error;
 565         }
 566         objd_set_private(list_objd, list);
 567
 568         /* populate list by walking on all registered probes. */
 569         ret = ltt_probes_get_event_list(list);
 570         if (ret) {
 571                 goto list_error;
 572         }
 573         return list_objd;
 574
 575 list_error:
 576         free(list);
 577 alloc_error:
 578         {
 579                 int err;
 580
 581                 err = lttng_ust_objd_unref(list_objd);
 582                 assert(!err);
 583         }
 584 objd_error:
 585         return ret;
 586 }
 587
 588 static
 589 int lttng_release_tracepoint_list(int objd)
 590 {
 591         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 592
 593         if (list) {
 594                 ltt_probes_prune_event_list(list);
 595                 free(list);
 596                 return 0;
 597         } else {
 598                 return -EINVAL;
 599         }
 600 }
 601
 602 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops = {
 603         .release = lttng_release_tracepoint_list,
 604         .cmd = lttng_tracepoint_list_cmd,
 605 };
 606
 607 struct stream_priv_data {
 608         struct lttng_ust_lib_ring_buffer *buf;
 609         struct ltt_channel *ltt_chan;
 610 };
 611
 612 static
 613 int lttng_abi_open_stream(int channel_objd, struct lttng_ust_stream *info,
 614                 union ust_args *uargs)
 615 {
 616         struct ltt_channel *channel = objd_private(channel_objd);
 617         struct lttng_ust_lib_ring_buffer *buf;
 618         struct stream_priv_data *priv;
 619         int stream_objd, ret;
 620
 621         buf = channel->ops->buffer_read_open(channel->chan, channel->handle,
 622                      &uargs->stream.shm_fd, &uargs->stream.shm_path,
 623                      &uargs->stream.wait_fd, &uargs->stream.wait_pipe_path,
 624                      &uargs->stream.memory_map_size);
 625         if (!buf)
 626                 return -ENOENT;
 627
 628         priv = zmalloc(sizeof(*priv));
 629         if (!priv) {
 630                 ret = -ENOMEM;
 631                 goto alloc_error;
 632         }
 633         priv->buf = buf;
 634         priv->ltt_chan = channel;
 635         stream_objd = objd_alloc(priv, &lib_ring_buffer_objd_ops);
 636         if (stream_objd < 0) {
 637                 ret = stream_objd;
 638                 goto objd_error;
 639         }
 640         /* Hold a reference on the channel object descriptor */
 641         objd_ref(channel_objd);
 642         return stream_objd;
 643
 644 objd_error:
 645         free(priv);
 646 alloc_error:
 647         channel->ops->buffer_read_close(buf, channel->handle);
 648         return ret;
 649 }
 650
 651 static
 652 int lttng_abi_create_event(int channel_objd,
 653                            struct lttng_ust_event *event_param)
 654 {
 655         struct ltt_channel *channel = objd_private(channel_objd);
 656         struct ltt_event *event;
 657         int event_objd, ret;
 658
 659         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 660         event_objd = objd_alloc(NULL, &lttng_event_ops);
 661         if (event_objd < 0) {
 662                 ret = event_objd;
 663                 goto objd_error;
 664         }
 665         /*
 666          * We tolerate no failure path after event creation. It will stay
 667          * invariant for the rest of the session.
 668          */
 669         ret = ltt_event_create(channel, event_param, NULL, &event);
 670         if (ret < 0) {
 671                 goto event_error;
 672         }
 673         objd_set_private(event_objd, event);
 674         /* The event holds a reference on the channel */
 675         objd_ref(channel_objd);
 676         return event_objd;
 677
 678 event_error:
 679         {
 680                 int err;
 681
 682                 err = lttng_ust_objd_unref(event_objd);
 683                 assert(!err);
 684         }
 685 objd_error:
 686         return ret;
 687 }
 688
 689 static
 690 int lttng_abi_create_wildcard(int channel_objd,
 691                               struct lttng_ust_event *event_param)
 692 {
 693         struct ltt_channel *channel = objd_private(channel_objd);
 694         struct session_wildcard *wildcard;
 695         int wildcard_objd, ret;
 696
 697         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 698         wildcard_objd = objd_alloc(NULL, &lttng_wildcard_ops);
 699         if (wildcard_objd < 0) {
 700                 ret = wildcard_objd;
 701                 goto objd_error;
 702         }
 703         /*
 704          * We tolerate no failure path after wildcard creation. It will
 705          * stay invariant for the rest of the session.
 706          */
 707         ret = ltt_wildcard_create(channel, event_param, &wildcard);
 708         if (ret < 0) {
 709                 goto wildcard_error;
 710         }
 711         objd_set_private(wildcard_objd, wildcard);
 712         /* The wildcard holds a reference on the channel */
 713         objd_ref(channel_objd);
 714         return wildcard_objd;
 715
 716 wildcard_error:
 717         {
 718                 int err;
 719
 720                 err = lttng_ust_objd_unref(wildcard_objd);
 721                 assert(!err);
 722         }
 723 objd_error:
 724         return ret;
 725 }
 726
 727 /**
 728  *      lttng_channel_cmd - lttng control through object descriptors
 729  *
 730  *      @objd: the object descriptor
 731  *      @cmd: the command
 732  *      @arg: command arg
 733  *      @uargs: UST arguments (internal)
 734  *
 735  *      This object descriptor implements lttng commands:
 736  *      LTTNG_UST_STREAM
 737  *              Returns an event stream object descriptor or failure.
 738  *              (typically, one event stream records events from one CPU)
 739  *      LTTNG_UST_EVENT
 740  *              Returns an event object descriptor or failure.
 741  *      LTTNG_UST_CONTEXT
 742  *              Prepend a context field to each event in the channel
 743  *      LTTNG_UST_ENABLE
 744  *              Enable recording for events in this channel (weak enable)
 745  *      LTTNG_UST_DISABLE
 746  *              Disable recording for events in this channel (strong disable)
 747  *
 748  * Channel and event file descriptors also hold a reference on the session.
 749  */
 750 static
 751 long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg,
 752         union ust_args *uargs)
 753 {
 754         struct ltt_channel *channel = objd_private(objd);
 755
 756         switch (cmd) {
 757         case LTTNG_UST_STREAM:
 758         {
 759                 struct lttng_ust_stream *stream;
 760
 761                 stream = (struct lttng_ust_stream *) arg;
 762                 /* stream used as output */
 763                 return lttng_abi_open_stream(objd, stream, uargs);
 764         }
 765         case LTTNG_UST_EVENT:
 766         {
 767                 struct lttng_ust_event *event_param =
 768                         (struct lttng_ust_event *) arg;
 769                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
 770                         /* If ends with wildcard, create wildcard. */
 771                         return lttng_abi_create_wildcard(objd, event_param);
 772                 } else {
 773                         return lttng_abi_create_event(objd, event_param);
 774                 }
 775         }
 776         case LTTNG_UST_CONTEXT:
 777                 return lttng_abi_add_context(objd,
 778                                 (struct lttng_ust_context *) arg,
 779                                 &channel->ctx, channel->session);
 780         case LTTNG_UST_ENABLE:
 781                 return ltt_channel_enable(channel);
 782         case LTTNG_UST_DISABLE:
 783                 return ltt_channel_disable(channel);
 784         case LTTNG_UST_FLUSH_BUFFER:
 785                 return channel->ops->flush_buffer(channel->chan, channel->handle);
 786         default:
 787                 return -EINVAL;
 788         }
 789 }
 790
 791 /**
 792  *      lttng_metadata_cmd - lttng control through object descriptors
 793  *
 794  *      @objd: the object descriptor
 795  *      @cmd: the command
 796  *      @arg: command arg
 797  *      @uargs: UST arguments (internal)
 798  *
 799  *      This object descriptor implements lttng commands:
 800  *      LTTNG_UST_STREAM
 801  *              Returns an event stream file descriptor or failure.
 802  *
 803  * Channel and event file descriptors also hold a reference on the session.
 804  */
 805 static
 806 long lttng_metadata_cmd(int objd, unsigned int cmd, unsigned long arg,
 807         union ust_args *uargs)
 808 {
 809         struct ltt_channel *channel = objd_private(objd);
 810
 811         switch (cmd) {
 812         case LTTNG_UST_STREAM:
 813         {
 814                 struct lttng_ust_stream *stream;
 815
 816                 stream = (struct lttng_ust_stream *) arg;
 817                 /* stream used as output */
 818                 return lttng_abi_open_stream(objd, stream, uargs);
 819         }
 820         case LTTNG_UST_FLUSH_BUFFER:
 821                 return channel->ops->flush_buffer(channel->chan, channel->handle);
 822         default:
 823                 return -EINVAL;
 824         }
 825 }
 826
 827 #if 0
 828 /**
 829  *      lttng_channel_poll - lttng stream addition/removal monitoring
 830  *
 831  *      @file: the file
 832  *      @wait: poll table
 833  */
 834 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
 835 {
 836         struct ltt_channel *channel = file->private_data;
 837         unsigned int mask = 0;
 838
 839         if (file->f_mode & FMODE_READ) {
 840                 poll_wait_set_exclusive(wait);
 841                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
 842                           wait);
 843
 844                 if (channel->ops->is_disabled(channel->chan))
 845                         return POLLERR;
 846                 if (channel->ops->is_finalized(channel->chan))
 847                         return POLLHUP;
 848                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
 849                         return POLLIN | POLLRDNORM;
 850                 return 0;
 851         }
 852         return mask;
 853
 854 }
 855 #endif //0
 856
 857 static
 858 int lttng_channel_release(int objd)
 859 {
 860         struct ltt_channel *channel = objd_private(objd);
 861
 862         if (channel)
 863                 return lttng_ust_objd_unref(channel->session->objd);
 864         return 0;
 865 }
 866
 867 static const struct lttng_ust_objd_ops lttng_channel_ops = {
 868         .release = lttng_channel_release,
 869         //.poll = lttng_channel_poll,
 870         .cmd = lttng_channel_cmd,
 871 };
 872
 873 static const struct lttng_ust_objd_ops lttng_metadata_ops = {
 874         .release = lttng_channel_release,
 875         .cmd = lttng_metadata_cmd,
 876 };
 877
 878 /**
 879  *      lttng_rb_cmd - lttng ring buffer control through object descriptors
 880  *
 881  *      @objd: the object descriptor
 882  *      @cmd: the command
 883  *      @arg: command arg
 884  *      @uargs: UST arguments (internal)
 885  *
 886  *      This object descriptor implements lttng commands:
 887  *              (None for now. Access is done directly though shm.)
 888  */
 889 static
 890 long lttng_rb_cmd(int objd, unsigned int cmd, unsigned long arg,
 891         union ust_args *uargs)
 892 {
 893         switch (cmd) {
 894         default:
 895                 return -EINVAL;
 896         }
 897 }
 898
 899 static
 900 int lttng_rb_release(int objd)
 901 {
 902         struct stream_priv_data *priv = objd_private(objd);
 903         struct lttng_ust_lib_ring_buffer *buf;
 904         struct ltt_channel *channel;
 905
 906         if (priv) {
 907                 buf = priv->buf;
 908                 channel = priv->ltt_chan;
 909                 free(priv);
 910                 /*
 911                  * If we are at ABI exit, we don't want to close the
 912                  * buffer opened for read: it is being shared between
 913                  * the parent and child (right after fork), and we don't
 914                  * want the child to close it for the parent. For a real
 915                  * exit, we don't care about marking it as closed, as
 916                  * the consumer daemon (if there is one) will do fine
 917                  * even if we don't mark it as "closed" for reading on
 918                  * our side.
 919                  * We only mark it as closed if it is being explicitely
 920                  * released by the session daemon with an explicit
 921                  * release command.
 922                  */
 923                 if (!lttng_ust_abi_close_in_progress)
 924                         channel->ops->buffer_read_close(buf, channel->handle);
 925
 926                 return lttng_ust_objd_unref(channel->objd);
 927         }
 928         return 0;
 929 }
 930
 931 static const struct lttng_ust_objd_ops lib_ring_buffer_objd_ops = {
 932         .release = lttng_rb_release,
 933         .cmd = lttng_rb_cmd,
 934 };
 935
 936 /**
 937  *      lttng_event_cmd - lttng control through object descriptors
 938  *
 939  *      @objd: the object descriptor
 940  *      @cmd: the command
 941  *      @arg: command arg
 942  *      @uargs: UST arguments (internal)
 943  *
 944  *      This object descriptor implements lttng commands:
 945  *      LTTNG_UST_CONTEXT
 946  *              Prepend a context field to each record of this event
 947  *      LTTNG_UST_ENABLE
 948  *              Enable recording for this event (weak enable)
 949  *      LTTNG_UST_DISABLE
 950  *              Disable recording for this event (strong disable)
 951  */
 952 static
 953 long lttng_event_cmd(int objd, unsigned int cmd, unsigned long arg,
 954         union ust_args *uargs)
 955 {
 956         struct ltt_event *event = objd_private(objd);
 957
 958         switch (cmd) {
 959         case LTTNG_UST_CONTEXT:
 960                 return lttng_abi_add_context(objd,
 961                                 (struct lttng_ust_context *) arg,
 962                                 &event->ctx, event->chan->session);
 963         case LTTNG_UST_ENABLE:
 964                 return ltt_event_enable(event);
 965         case LTTNG_UST_DISABLE:
 966                 return ltt_event_disable(event);
 967         default:
 968                 return -EINVAL;
 969         }
 970 }
 971
 972 static
 973 int lttng_event_release(int objd)
 974 {
 975         struct ltt_event *event = objd_private(objd);
 976
 977         if (event)
 978                 return lttng_ust_objd_unref(event->chan->objd);
 979         return 0;
 980 }
 981
 982 /* TODO: filter control ioctl */
 983 static const struct lttng_ust_objd_ops lttng_event_ops = {
 984         .release = lttng_event_release,
 985         .cmd = lttng_event_cmd,
 986 };
 987
 988 /**
 989  *      lttng_wildcard_cmd - lttng control through object descriptors
 990  *
 991  *      @objd: the object descriptor
 992  *      @cmd: the command
 993  *      @arg: command arg
 994  *      @uargs: UST arguments (internal)
 995  *
 996  *      This object descriptor implements lttng commands:
 997  *      LTTNG_UST_CONTEXT
 998  *              Prepend a context field to each record of events of this
 999  *              wildcard.
1000  *      LTTNG_UST_ENABLE
1001  *              Enable recording for these wildcard events (weak enable)
1002  *      LTTNG_UST_DISABLE
1003  *              Disable recording for these wildcard events (strong disable)
1004  */
1005 static
1006 long lttng_wildcard_cmd(int objd, unsigned int cmd, unsigned long arg,
1007         union ust_args *uargs)
1008 {
1009         struct session_wildcard *wildcard = objd_private(objd);
1010
1011         switch (cmd) {
1012         case LTTNG_UST_CONTEXT:
1013                 return -ENOSYS; /* not implemented yet */
1014 #if 0
1015                 return lttng_abi_add_context(objd,
1016                                 (struct lttng_ust_context *) arg,
1017                                 &wildcard->ctx, wildcard->chan->session);
1018 #endif
1019         case LTTNG_UST_ENABLE:
1020                 return ltt_wildcard_enable(wildcard);
1021         case LTTNG_UST_DISABLE:
1022                 return ltt_wildcard_disable(wildcard);
1023         default:
1024                 return -EINVAL;
1025         }
1026 }
1027
1028 static
1029 int lttng_wildcard_release(int objd)
1030 {
1031         struct session_wildcard *wildcard = objd_private(objd);
1032
1033         if (wildcard)
1034                 return lttng_ust_objd_unref(wildcard->chan->objd);
1035         return 0;
1036 }
1037
1038 /* TODO: filter control ioctl */
1039 static const struct lttng_ust_objd_ops lttng_wildcard_ops = {
1040         .release = lttng_wildcard_release,
1041         .cmd = lttng_wildcard_cmd,
1042 };
1043
1044 void lttng_ust_abi_exit(void)
1045 {
1046         lttng_ust_abi_close_in_progress = 1;
1047         objd_table_destroy();
1048         lttng_ust_abi_close_in_progress = 0;
1049 }