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 #define _LGPL_SOURCE
  41 #include <fcntl.h>
  42 #include <stdint.h>
  43 #include <unistd.h>
  44
  45 #include <urcu/compiler.h>
  46 #include <urcu/list.h>
  47
  48 #include <helper.h>
  49 #include <lttng/tracepoint.h>
  50 #include <lttng/ust-abi.h>
  51 #include <lttng/ust-error.h>
  52 #include <lttng/ust-events.h>
  53 #include <lttng/ust-version.h>
  54 #include <ust-fd.h>
  55 #include <usterr-signal-safe.h>
  56
  57 #include "../libringbuffer/frontend_types.h"
  58 #include "../libringbuffer/shm.h"
  59 #include "../libcounter/counter.h"
  60 #include "tracepoint-internal.h"
  61 #include "lttng-tracer.h"
  62 #include "string-utils.h"
  63 #include "ust-events-internal.h"
  64
  65 #define OBJ_NAME_LEN    16
  66
  67 static int lttng_ust_abi_close_in_progress;
  68
  69 static
  70 int lttng_abi_tracepoint_list(void *owner);
  71 static
  72 int lttng_abi_tracepoint_field_list(void *owner);
  73
  74 /*
  75  * Object descriptor table. Should be protected from concurrent access
  76  * by the caller.
  77  */
  78
  79 struct lttng_ust_obj {
  80         union {
  81                 struct {
  82                         void *private_data;
  83                         const struct lttng_ust_objd_ops *ops;
  84                         int f_count;
  85                         int owner_ref;  /* has ref from owner */
  86                         void *owner;
  87                         char name[OBJ_NAME_LEN];
  88                 } s;
  89                 int freelist_next;      /* offset freelist. end is -1. */
  90         } u;
  91 };
  92
  93 struct lttng_ust_objd_table {
  94         struct lttng_ust_obj *array;
  95         unsigned int len, allocated_len;
  96         int freelist_head;              /* offset freelist head. end is -1 */
  97 };
  98
  99 static struct lttng_ust_objd_table objd_table = {
 100         .freelist_head = -1,
 101 };
 102
 103 static
 104 int objd_alloc(void *private_data, const struct lttng_ust_objd_ops *ops,
 105                 void *owner, const char *name)
 106 {
 107         struct lttng_ust_obj *obj;
 108
 109         if (objd_table.freelist_head != -1) {
 110                 obj = &objd_table.array[objd_table.freelist_head];
 111                 objd_table.freelist_head = obj->u.freelist_next;
 112                 goto end;
 113         }
 114
 115         if (objd_table.len >= objd_table.allocated_len) {
 116                 unsigned int new_allocated_len, old_allocated_len;
 117                 struct lttng_ust_obj *new_table, *old_table;
 118
 119                 old_allocated_len = objd_table.allocated_len;
 120                 old_table = objd_table.array;
 121                 if (!old_allocated_len)
 122                         new_allocated_len = 1;
 123                 else
 124                         new_allocated_len = old_allocated_len << 1;
 125                 new_table = zmalloc(sizeof(struct lttng_ust_obj) * new_allocated_len);
 126                 if (!new_table)
 127                         return -ENOMEM;
 128                 memcpy(new_table, old_table,
 129                        sizeof(struct lttng_ust_obj) * old_allocated_len);
 130                 free(old_table);
 131                 objd_table.array = new_table;
 132                 objd_table.allocated_len = new_allocated_len;
 133         }
 134         obj = &objd_table.array[objd_table.len];
 135         objd_table.len++;
 136 end:
 137         obj->u.s.private_data = private_data;
 138         obj->u.s.ops = ops;
 139         obj->u.s.f_count = 2;   /* count == 1 : object is allocated */
 140                                 /* count == 2 : allocated + hold ref */
 141         obj->u.s.owner_ref = 1; /* One owner reference */
 142         obj->u.s.owner = owner;
 143         strncpy(obj->u.s.name, name, OBJ_NAME_LEN);
 144         obj->u.s.name[OBJ_NAME_LEN - 1] = '\0';
 145         return obj - objd_table.array;
 146 }
 147
 148 static
 149 struct lttng_ust_obj *_objd_get(int id)
 150 {
 151         if (id >= objd_table.len)
 152                 return NULL;
 153         if (!objd_table.array[id].u.s.f_count)
 154                 return NULL;
 155         return &objd_table.array[id];
 156 }
 157
 158 static
 159 void *objd_private(int id)
 160 {
 161         struct lttng_ust_obj *obj = _objd_get(id);
 162         assert(obj);
 163         return obj->u.s.private_data;
 164 }
 165
 166 static
 167 void objd_set_private(int id, void *private_data)
 168 {
 169         struct lttng_ust_obj *obj = _objd_get(id);
 170         assert(obj);
 171         obj->u.s.private_data = private_data;
 172 }
 173
 174 const struct lttng_ust_objd_ops *objd_ops(int id)
 175 {
 176         struct lttng_ust_obj *obj = _objd_get(id);
 177
 178         if (!obj)
 179                 return NULL;
 180         return obj->u.s.ops;
 181 }
 182
 183 static
 184 void objd_free(int id)
 185 {
 186         struct lttng_ust_obj *obj = _objd_get(id);
 187
 188         assert(obj);
 189         obj->u.freelist_next = objd_table.freelist_head;
 190         objd_table.freelist_head = obj - objd_table.array;
 191         assert(obj->u.s.f_count == 1);
 192         obj->u.s.f_count = 0;   /* deallocated */
 193 }
 194
 195 static
 196 void objd_ref(int id)
 197 {
 198         struct lttng_ust_obj *obj = _objd_get(id);
 199         assert(obj != NULL);
 200         obj->u.s.f_count++;
 201 }
 202
 203 int lttng_ust_objd_unref(int id, int is_owner)
 204 {
 205         struct lttng_ust_obj *obj = _objd_get(id);
 206
 207         if (!obj)
 208                 return -EINVAL;
 209         if (obj->u.s.f_count == 1) {
 210                 ERR("Reference counting error\n");
 211                 return -EINVAL;
 212         }
 213         if (is_owner) {
 214                 if (!obj->u.s.owner_ref) {
 215                         ERR("Error decrementing owner reference");
 216                         return -EINVAL;
 217                 }
 218                 obj->u.s.owner_ref--;
 219         }
 220         if ((--obj->u.s.f_count) == 1) {
 221                 const struct lttng_ust_objd_ops *ops = objd_ops(id);
 222
 223                 if (ops->release)
 224                         ops->release(id);
 225                 objd_free(id);
 226         }
 227         return 0;
 228 }
 229
 230 static
 231 void objd_table_destroy(void)
 232 {
 233         int i;
 234
 235         for (i = 0; i < objd_table.allocated_len; i++) {
 236                 struct lttng_ust_obj *obj;
 237
 238                 obj = _objd_get(i);
 239                 if (!obj)
 240                         continue;
 241                 if (!obj->u.s.owner_ref)
 242                         continue;       /* only unref owner ref. */
 243                 (void) lttng_ust_objd_unref(i, 1);
 244         }
 245         free(objd_table.array);
 246         objd_table.array = NULL;
 247         objd_table.len = 0;
 248         objd_table.allocated_len = 0;
 249         objd_table.freelist_head = -1;
 250 }
 251
 252 const char *lttng_ust_obj_get_name(int id)
 253 {
 254         struct lttng_ust_obj *obj = _objd_get(id);
 255
 256         if (!obj)
 257                 return NULL;
 258         return obj->u.s.name;
 259 }
 260
 261 void lttng_ust_objd_table_owner_cleanup(void *owner)
 262 {
 263         int i;
 264
 265         for (i = 0; i < objd_table.allocated_len; i++) {
 266                 struct lttng_ust_obj *obj;
 267
 268                 obj = _objd_get(i);
 269                 if (!obj)
 270                         continue;
 271                 if (!obj->u.s.owner)
 272                         continue;       /* skip root handles */
 273                 if (!obj->u.s.owner_ref)
 274                         continue;       /* only unref owner ref. */
 275                 if (obj->u.s.owner == owner)
 276                         (void) lttng_ust_objd_unref(i, 1);
 277         }
 278 }
 279
 280 /*
 281  * This is LTTng's own personal way to create an ABI for sessiond.
 282  * We send commands over a socket.
 283  */
 284
 285 static const struct lttng_ust_objd_ops lttng_ops;
 286 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops;
 287 static const struct lttng_ust_objd_ops lttng_session_ops;
 288 static const struct lttng_ust_objd_ops lttng_channel_ops;
 289 static const struct lttng_ust_objd_ops lttng_event_enabler_ops;
 290 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops;
 291 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops;
 292 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops;
 293
 294 int lttng_abi_create_root_handle(void)
 295 {
 296         int root_handle;
 297
 298         /* root handles have NULL owners */
 299         root_handle = objd_alloc(NULL, &lttng_ops, NULL, "root");
 300         return root_handle;
 301 }
 302
 303 static
 304 int lttng_is_channel_ready(struct lttng_channel *lttng_chan)
 305 {
 306         struct channel *chan;
 307         unsigned int nr_streams, exp_streams;
 308
 309         chan = lttng_chan->chan;
 310         nr_streams = channel_handle_get_nr_streams(lttng_chan->handle);
 311         exp_streams = chan->nr_streams;
 312         return nr_streams == exp_streams;
 313 }
 314
 315 static
 316 int lttng_abi_create_session(void *owner)
 317 {
 318         struct lttng_session *session;
 319         int session_objd, ret;
 320
 321         session = lttng_session_create();
 322         if (!session)
 323                 return -ENOMEM;
 324         session_objd = objd_alloc(session, &lttng_session_ops, owner, "session");
 325         if (session_objd < 0) {
 326                 ret = session_objd;
 327                 goto objd_error;
 328         }
 329         session->objd = session_objd;
 330         session->owner = owner;
 331         return session_objd;
 332
 333 objd_error:
 334         lttng_session_destroy(session);
 335         return ret;
 336 }
 337
 338 static
 339 long lttng_abi_tracer_version(int objd,
 340         struct lttng_ust_tracer_version *v)
 341 {
 342         v->major = LTTNG_UST_MAJOR_VERSION;
 343         v->minor = LTTNG_UST_MINOR_VERSION;
 344         v->patchlevel = LTTNG_UST_PATCHLEVEL_VERSION;
 345         return 0;
 346 }
 347
 348 static
 349 int lttng_abi_event_notifier_send_fd(void *owner, int event_notifier_notif_fd)
 350 {
 351         struct lttng_event_notifier_group *event_notifier_group;
 352         int event_notifier_group_objd, ret, fd_flag, close_ret;
 353
 354         event_notifier_group = lttng_event_notifier_group_create();
 355         if (!event_notifier_group)
 356                 return -ENOMEM;
 357
 358         /*
 359          * Set this file descriptor as NON-BLOCKING.
 360          */
 361         fd_flag = fcntl(event_notifier_notif_fd, F_GETFL);
 362
 363         fd_flag |= O_NONBLOCK;
 364
 365         ret = fcntl(event_notifier_notif_fd, F_SETFL, fd_flag);
 366         if (ret) {
 367                 ret = -errno;
 368                 goto fd_error;
 369         }
 370
 371         event_notifier_group_objd = objd_alloc(event_notifier_group,
 372                 &lttng_event_notifier_group_ops, owner, "event_notifier_group");
 373         if (event_notifier_group_objd < 0) {
 374                 ret = event_notifier_group_objd;
 375                 goto objd_error;
 376         }
 377
 378         event_notifier_group->objd = event_notifier_group_objd;
 379         event_notifier_group->owner = owner;
 380         event_notifier_group->notification_fd = event_notifier_notif_fd;
 381
 382         return event_notifier_group_objd;
 383
 384 objd_error:
 385         lttng_event_notifier_group_destroy(event_notifier_group);
 386 fd_error:
 387         close_ret = close(event_notifier_notif_fd);
 388         if (close_ret) {
 389                 PERROR("close");
 390         }
 391
 392         return ret;
 393 }
 394
 395 static
 396 long lttng_abi_add_context(int objd,
 397         struct lttng_ust_context *context_param,
 398         union ust_args *uargs,
 399         struct lttng_ctx **ctx, struct lttng_session *session)
 400 {
 401         return lttng_attach_context(context_param, uargs, ctx, session);
 402 }
 403
 404 /**
 405  *      lttng_cmd - lttng control through socket commands
 406  *
 407  *      @objd: the object descriptor
 408  *      @cmd: the command
 409  *      @arg: command arg
 410  *      @uargs: UST arguments (internal)
 411  *      @owner: objd owner
 412  *
 413  *      This descriptor implements lttng commands:
 414  *      LTTNG_UST_SESSION
 415  *              Returns a LTTng trace session object descriptor
 416  *      LTTNG_UST_TRACER_VERSION
 417  *              Returns the LTTng kernel tracer version
 418  *      LTTNG_UST_TRACEPOINT_LIST
 419  *              Returns a file descriptor listing available tracepoints
 420  *      LTTNG_UST_TRACEPOINT_FIELD_LIST
 421  *              Returns a file descriptor listing available tracepoint fields
 422  *      LTTNG_UST_WAIT_QUIESCENT
 423  *              Returns after all previously running probes have completed
 424  *
 425  * The returned session will be deleted when its file descriptor is closed.
 426  */
 427 static
 428 long lttng_cmd(int objd, unsigned int cmd, unsigned long arg,
 429         union ust_args *uargs, void *owner)
 430 {
 431         switch (cmd) {
 432         case LTTNG_UST_SESSION:
 433                 return lttng_abi_create_session(owner);
 434         case LTTNG_UST_TRACER_VERSION:
 435                 return lttng_abi_tracer_version(objd,
 436                                 (struct lttng_ust_tracer_version *) arg);
 437         case LTTNG_UST_TRACEPOINT_LIST:
 438                 return lttng_abi_tracepoint_list(owner);
 439         case LTTNG_UST_TRACEPOINT_FIELD_LIST:
 440                 return lttng_abi_tracepoint_field_list(owner);
 441         case LTTNG_UST_WAIT_QUIESCENT:
 442                 lttng_ust_synchronize_trace();
 443                 return 0;
 444         case LTTNG_UST_EVENT_NOTIFIER_GROUP_CREATE:
 445                 return lttng_abi_event_notifier_send_fd(owner,
 446                         uargs->event_notifier_handle.event_notifier_notif_fd);
 447         default:
 448                 return -EINVAL;
 449         }
 450 }
 451
 452 static const struct lttng_ust_objd_ops lttng_ops = {
 453         .cmd = lttng_cmd,
 454 };
 455
 456 int lttng_abi_map_channel(int session_objd,
 457                 struct lttng_ust_channel *ust_chan,
 458                 union ust_args *uargs,
 459                 void *owner)
 460 {
 461         struct lttng_session *session = objd_private(session_objd);
 462         const char *transport_name;
 463         const struct lttng_transport *transport;
 464         const char *chan_name;
 465         int chan_objd;
 466         struct lttng_ust_shm_handle *channel_handle;
 467         struct lttng_channel *lttng_chan;
 468         struct channel *chan;
 469         struct lttng_ust_lib_ring_buffer_config *config;
 470         void *chan_data;
 471         int wakeup_fd;
 472         uint64_t len;
 473         int ret;
 474         enum lttng_ust_chan_type type;
 475
 476         chan_data = uargs->channel.chan_data;
 477         wakeup_fd = uargs->channel.wakeup_fd;
 478         len = ust_chan->len;
 479         type = ust_chan->type;
 480
 481         switch (type) {
 482         case LTTNG_UST_CHAN_PER_CPU:
 483                 break;
 484         default:
 485                 ret = -EINVAL;
 486                 goto invalid;
 487         }
 488
 489         if (session->been_active) {
 490                 ret = -EBUSY;
 491                 goto active;    /* Refuse to add channel to active session */
 492         }
 493
 494         channel_handle = channel_handle_create(chan_data, len, wakeup_fd);
 495         if (!channel_handle) {
 496                 ret = -EINVAL;
 497                 goto handle_error;
 498         }
 499
 500         chan = shmp(channel_handle, channel_handle->chan);
 501         assert(chan);
 502         chan->handle = channel_handle;
 503         config = &chan->backend.config;
 504         lttng_chan = channel_get_private(chan);
 505         if (!lttng_chan) {
 506                 ret = -EINVAL;
 507                 goto alloc_error;
 508         }
 509
 510         /* Lookup transport name */
 511         switch (type) {
 512         case LTTNG_UST_CHAN_PER_CPU:
 513                 if (config->output == RING_BUFFER_MMAP) {
 514                         if (config->mode == RING_BUFFER_OVERWRITE) {
 515                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 516                                         transport_name = "relay-overwrite-mmap";
 517                                 } else {
 518                                         transport_name = "relay-overwrite-rt-mmap";
 519                                 }
 520                         } else {
 521                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 522                                         transport_name = "relay-discard-mmap";
 523                                 } else {
 524                                         transport_name = "relay-discard-rt-mmap";
 525                                 }
 526                         }
 527                 } else {
 528                         ret = -EINVAL;
 529                         goto notransport;
 530                 }
 531                 chan_name = "channel";
 532                 break;
 533         default:
 534                 ret = -EINVAL;
 535                 goto notransport;
 536         }
 537         transport = lttng_transport_find(transport_name);
 538         if (!transport) {
 539                 DBG("LTTng transport %s not found\n",
 540                        transport_name);
 541                 ret = -EINVAL;
 542                 goto notransport;
 543         }
 544
 545         chan_objd = objd_alloc(NULL, &lttng_channel_ops, owner, chan_name);
 546         if (chan_objd < 0) {
 547                 ret = chan_objd;
 548                 goto objd_error;
 549         }
 550
 551         /* Initialize our lttng chan */
 552         lttng_chan->chan = chan;
 553         lttng_chan->tstate = 1;
 554         lttng_chan->enabled = 1;
 555         lttng_chan->ctx = NULL;
 556         lttng_chan->session = session;
 557         lttng_chan->ops = &transport->ops;
 558         memcpy(&lttng_chan->chan->backend.config,
 559                 transport->client_config,
 560                 sizeof(lttng_chan->chan->backend.config));
 561         cds_list_add(&lttng_chan->node, &session->chan_head);
 562         lttng_chan->header_type = 0;
 563         lttng_chan->handle = channel_handle;
 564         lttng_chan->type = type;
 565
 566         /*
 567          * We tolerate no failure path after channel creation. It will stay
 568          * invariant for the rest of the session.
 569          */
 570         objd_set_private(chan_objd, lttng_chan);
 571         lttng_chan->objd = chan_objd;
 572         /* The channel created holds a reference on the session */
 573         objd_ref(session_objd);
 574         return chan_objd;
 575
 576         /* error path after channel was created */
 577 objd_error:
 578 notransport:
 579 alloc_error:
 580         channel_destroy(chan, channel_handle, 0);
 581         return ret;
 582
 583         /*
 584          * error path before channel creation (owning chan_data and
 585          * wakeup_fd).
 586          */
 587 handle_error:
 588 active:
 589 invalid:
 590         {
 591                 int close_ret;
 592
 593                 lttng_ust_lock_fd_tracker();
 594                 close_ret = close(wakeup_fd);
 595                 lttng_ust_unlock_fd_tracker();
 596                 if (close_ret) {
 597                         PERROR("close");
 598                 }
 599         }
 600         free(chan_data);
 601         return ret;
 602 }
 603
 604 /**
 605  *      lttng_session_cmd - lttng session object command
 606  *
 607  *      @obj: the object
 608  *      @cmd: the command
 609  *      @arg: command arg
 610  *      @uargs: UST arguments (internal)
 611  *      @owner: objd owner
 612  *
 613  *      This descriptor implements lttng commands:
 614  *      LTTNG_UST_CHANNEL
 615  *              Returns a LTTng channel object descriptor
 616  *      LTTNG_UST_ENABLE
 617  *              Enables tracing for a session (weak enable)
 618  *      LTTNG_UST_DISABLE
 619  *              Disables tracing for a session (strong disable)
 620  *
 621  * The returned channel will be deleted when its file descriptor is closed.
 622  */
 623 static
 624 long lttng_session_cmd(int objd, unsigned int cmd, unsigned long arg,
 625         union ust_args *uargs, void *owner)
 626 {
 627         struct lttng_session *session = objd_private(objd);
 628
 629         switch (cmd) {
 630         case LTTNG_UST_CHANNEL:
 631                 return lttng_abi_map_channel(objd,
 632                                 (struct lttng_ust_channel *) arg,
 633                                 uargs, owner);
 634         case LTTNG_UST_SESSION_START:
 635         case LTTNG_UST_ENABLE:
 636                 return lttng_session_enable(session);
 637         case LTTNG_UST_SESSION_STOP:
 638         case LTTNG_UST_DISABLE:
 639                 return lttng_session_disable(session);
 640         case LTTNG_UST_SESSION_STATEDUMP:
 641                 return lttng_session_statedump(session);
 642         case LTTNG_UST_COUNTER:
 643         case LTTNG_UST_COUNTER_GLOBAL:
 644         case LTTNG_UST_COUNTER_CPU:
 645                 /* Not implemented yet. */
 646                 return -EINVAL;
 647         default:
 648                 return -EINVAL;
 649         }
 650 }
 651
 652 /*
 653  * Called when the last file reference is dropped.
 654  *
 655  * Big fat note: channels and events are invariant for the whole session after
 656  * their creation. So this session destruction also destroys all channel and
 657  * event structures specific to this session (they are not destroyed when their
 658  * individual file is released).
 659  */
 660 static
 661 int lttng_release_session(int objd)
 662 {
 663         struct lttng_session *session = objd_private(objd);
 664
 665         if (session) {
 666                 lttng_session_destroy(session);
 667                 return 0;
 668         } else {
 669                 return -EINVAL;
 670         }
 671 }
 672
 673 static const struct lttng_ust_objd_ops lttng_session_ops = {
 674         .release = lttng_release_session,
 675         .cmd = lttng_session_cmd,
 676 };
 677
 678 static int lttng_ust_event_notifier_enabler_create(int event_notifier_group_obj,
 679                 void *owner, struct lttng_ust_event_notifier *event_notifier_param,
 680                 enum lttng_enabler_format_type type)
 681 {
 682         struct lttng_event_notifier_group *event_notifier_group =
 683                 objd_private(event_notifier_group_obj);
 684         struct lttng_event_notifier_enabler *event_notifier_enabler;
 685         int event_notifier_objd, ret;
 686
 687         event_notifier_param->event.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 688         event_notifier_objd = objd_alloc(NULL, &lttng_event_notifier_enabler_ops, owner,
 689                 "event_notifier enabler");
 690         if (event_notifier_objd < 0) {
 691                 ret = event_notifier_objd;
 692                 goto objd_error;
 693         }
 694
 695         event_notifier_enabler = lttng_event_notifier_enabler_create(
 696                 event_notifier_group, type, event_notifier_param);
 697         if (!event_notifier_enabler) {
 698                 ret = -ENOMEM;
 699                 goto event_notifier_error;
 700         }
 701
 702         objd_set_private(event_notifier_objd, event_notifier_enabler);
 703         /* The event_notifier holds a reference on the event_notifier group. */
 704         objd_ref(event_notifier_enabler->group->objd);
 705
 706         return event_notifier_objd;
 707
 708 event_notifier_error:
 709         {
 710                 int err;
 711
 712                 err = lttng_ust_objd_unref(event_notifier_objd, 1);
 713                 assert(!err);
 714         }
 715 objd_error:
 716         return ret;
 717 }
 718
 719 static
 720 long lttng_event_notifier_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
 721                 union ust_args *uargs, void *owner)
 722 {
 723         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 724         switch (cmd) {
 725         case LTTNG_UST_FILTER:
 726                 return lttng_event_notifier_enabler_attach_filter_bytecode(
 727                         event_notifier_enabler,
 728                         (struct lttng_ust_bytecode_node *) arg);
 729         case LTTNG_UST_EXCLUSION:
 730                 return lttng_event_notifier_enabler_attach_exclusion(event_notifier_enabler,
 731                         (struct lttng_ust_excluder_node *) arg);
 732         case LTTNG_UST_CAPTURE:
 733                 return lttng_event_notifier_enabler_attach_capture_bytecode(
 734                         event_notifier_enabler,
 735                         (struct lttng_ust_bytecode_node *) arg);
 736         case LTTNG_UST_ENABLE:
 737                 return lttng_event_notifier_enabler_enable(event_notifier_enabler);
 738         case LTTNG_UST_DISABLE:
 739                 return lttng_event_notifier_enabler_disable(event_notifier_enabler);
 740         default:
 741                 return -EINVAL;
 742         }
 743 }
 744
 745 /**
 746  *      lttng_event_notifier_group_error_counter_cmd - lttng event_notifier group error counter object command
 747  *
 748  *      @obj: the object
 749  *      @cmd: the command
 750  *      @arg: command arg
 751  *      @uargs: UST arguments (internal)
 752  *      @owner: objd owner
 753  *
 754  *      This descriptor implements lttng commands:
 755  *      LTTNG_UST_COUNTER_GLOBAL
 756  *        Return negative error code on error, 0 on success.
 757  *      LTTNG_UST_COUNTER_CPU
 758  *        Return negative error code on error, 0 on success.
 759  */
 760 static
 761 long lttng_event_notifier_group_error_counter_cmd(int objd, unsigned int cmd, unsigned long arg,
 762         union ust_args *uargs, void *owner)
 763 {
 764         struct lttng_counter *counter = objd_private(objd);
 765
 766         switch (cmd) {
 767         case LTTNG_UST_COUNTER_GLOBAL:
 768                 return -EINVAL;         /* Unimplemented. */
 769         case LTTNG_UST_COUNTER_CPU:
 770         {
 771                 struct lttng_ust_counter_cpu *counter_cpu =
 772                         (struct lttng_ust_counter_cpu *)arg;
 773                 return lttng_counter_set_cpu_shm(counter->counter,
 774                         counter_cpu->cpu_nr, uargs->counter_shm.shm_fd);
 775         }
 776         default:
 777                 return -EINVAL;
 778         }
 779 }
 780
 781 int lttng_release_event_notifier_group_error_counter(int objd)
 782 {
 783         struct lttng_counter *counter = objd_private(objd);
 784
 785         if (counter) {
 786                 return lttng_ust_objd_unref(counter->event_notifier_group->objd, 0);
 787         } else {
 788                 return -EINVAL;
 789         }
 790 }
 791
 792 static const struct lttng_ust_objd_ops lttng_event_notifier_group_error_counter_ops = {
 793         .release = lttng_release_event_notifier_group_error_counter,
 794         .cmd = lttng_event_notifier_group_error_counter_cmd,
 795 };
 796
 797 static
 798 int lttng_ust_event_notifier_group_create_error_counter(int event_notifier_group_objd, void *owner,
 799                 struct lttng_ust_counter_conf *error_counter_conf)
 800 {
 801         const char *counter_transport_name;
 802         struct lttng_event_notifier_group *event_notifier_group =
 803                 objd_private(event_notifier_group_objd);
 804         struct lttng_counter *counter;
 805         int counter_objd, ret;
 806         struct lttng_counter_dimension dimensions[1];
 807         size_t counter_len;
 808
 809         if (event_notifier_group->error_counter)
 810                 return -EBUSY;
 811
 812         if (error_counter_conf->arithmetic != LTTNG_UST_COUNTER_ARITHMETIC_MODULAR)
 813                 return -EINVAL;
 814
 815         if (error_counter_conf->number_dimensions != 1)
 816                 return -EINVAL;
 817
 818         switch (error_counter_conf->bitness) {
 819         case LTTNG_UST_COUNTER_BITNESS_64:
 820                 counter_transport_name = "counter-per-cpu-64-modular";
 821                 break;
 822         case LTTNG_UST_COUNTER_BITNESS_32:
 823                 counter_transport_name = "counter-per-cpu-32-modular";
 824                 break;
 825         default:
 826                 return -EINVAL;
 827         }
 828
 829         counter_objd = objd_alloc(NULL, &lttng_event_notifier_group_error_counter_ops, owner,
 830                 "event_notifier group error counter");
 831         if (counter_objd < 0) {
 832                 ret = counter_objd;
 833                 goto objd_error;
 834         }
 835
 836         counter_len = error_counter_conf->dimensions[0].size;
 837         dimensions[0].size = counter_len;
 838         dimensions[0].underflow_index = 0;
 839         dimensions[0].overflow_index = 0;
 840         dimensions[0].has_underflow = 0;
 841         dimensions[0].has_overflow = 0;
 842
 843         counter = lttng_ust_counter_create(counter_transport_name, 1, dimensions);
 844         if (!counter) {
 845                 ret = -EINVAL;
 846                 goto create_error;
 847         }
 848
 849         event_notifier_group->error_counter_len = counter_len;
 850         /*
 851          * store-release to publish error counter matches load-acquire
 852          * in record_error. Ensures the counter is created and the
 853          * error_counter_len is set before they are used.
 854          * Currently a full memory barrier is used, which could be
 855          * turned into acquire-release barriers.
 856          */
 857         cmm_smp_mb();
 858         CMM_STORE_SHARED(event_notifier_group->error_counter, counter);
 859
 860         counter->objd = counter_objd;
 861         counter->event_notifier_group = event_notifier_group;   /* owner */
 862
 863         objd_set_private(counter_objd, counter);
 864         /* The error counter holds a reference on the event_notifier group. */
 865         objd_ref(event_notifier_group->objd);
 866
 867         return counter_objd;
 868
 869 create_error:
 870         {
 871                 int err;
 872
 873                 err = lttng_ust_objd_unref(counter_objd, 1);
 874                 assert(!err);
 875         }
 876 objd_error:
 877         return ret;
 878 }
 879
 880 static
 881 long lttng_event_notifier_group_cmd(int objd, unsigned int cmd, unsigned long arg,
 882                 union ust_args *uargs, void *owner)
 883 {
 884         switch (cmd) {
 885         case LTTNG_UST_EVENT_NOTIFIER_CREATE:
 886         {
 887                 struct lttng_ust_event_notifier *event_notifier_param =
 888                         (struct lttng_ust_event_notifier *) arg;
 889                 if (strutils_is_star_glob_pattern(event_notifier_param->event.name)) {
 890                         /*
 891                          * If the event name is a star globbing pattern,
 892                          * we create the special star globbing enabler.
 893                          */
 894                         return lttng_ust_event_notifier_enabler_create(objd,
 895                                         owner, event_notifier_param,
 896                                         LTTNG_ENABLER_FORMAT_STAR_GLOB);
 897                 } else {
 898                         return lttng_ust_event_notifier_enabler_create(objd,
 899                                         owner, event_notifier_param,
 900                                         LTTNG_ENABLER_FORMAT_EVENT);
 901                 }
 902         }
 903         case LTTNG_UST_COUNTER:
 904         {
 905                 struct lttng_ust_counter_conf *counter_conf =
 906                         (struct lttng_ust_counter_conf *) uargs->counter.counter_data;
 907                 return lttng_ust_event_notifier_group_create_error_counter(
 908                                 objd, owner, counter_conf);
 909         }
 910         default:
 911                 return -EINVAL;
 912         }
 913 }
 914
 915 static
 916 int lttng_event_notifier_enabler_release(int objd)
 917 {
 918         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 919
 920         if (event_notifier_enabler)
 921                 return lttng_ust_objd_unref(event_notifier_enabler->group->objd, 0);
 922         return 0;
 923 }
 924
 925 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops = {
 926         .release = lttng_event_notifier_enabler_release,
 927         .cmd = lttng_event_notifier_enabler_cmd,
 928 };
 929
 930 static
 931 int lttng_release_event_notifier_group(int objd)
 932 {
 933         struct lttng_event_notifier_group *event_notifier_group = objd_private(objd);
 934
 935         if (event_notifier_group) {
 936                 lttng_event_notifier_group_destroy(event_notifier_group);
 937                 return 0;
 938         } else {
 939                 return -EINVAL;
 940         }
 941 }
 942
 943 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops = {
 944         .release = lttng_release_event_notifier_group,
 945         .cmd = lttng_event_notifier_group_cmd,
 946 };
 947
 948 static
 949 long lttng_tracepoint_list_cmd(int objd, unsigned int cmd, unsigned long arg,
 950         union ust_args *uargs, void *owner)
 951 {
 952         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 953         struct lttng_ust_tracepoint_iter *tp =
 954                 (struct lttng_ust_tracepoint_iter *) arg;
 955         struct lttng_ust_tracepoint_iter *iter;
 956
 957         switch (cmd) {
 958         case LTTNG_UST_TRACEPOINT_LIST_GET:
 959         {
 960                 iter = lttng_ust_tracepoint_list_get_iter_next(list);
 961                 if (!iter)
 962                         return -LTTNG_UST_ERR_NOENT;
 963                 memcpy(tp, iter, sizeof(*tp));
 964                 return 0;
 965         }
 966         default:
 967                 return -EINVAL;
 968         }
 969 }
 970
 971 static
 972 int lttng_abi_tracepoint_list(void *owner)
 973 {
 974         int list_objd, ret;
 975         struct lttng_ust_tracepoint_list *list;
 976
 977         list_objd = objd_alloc(NULL, &lttng_tracepoint_list_ops, owner, "tp_list");
 978         if (list_objd < 0) {
 979                 ret = list_objd;
 980                 goto objd_error;
 981         }
 982         list = zmalloc(sizeof(*list));
 983         if (!list) {
 984                 ret = -ENOMEM;
 985                 goto alloc_error;
 986         }
 987         objd_set_private(list_objd, list);
 988
 989         /* populate list by walking on all registered probes. */
 990         ret = lttng_probes_get_event_list(list);
 991         if (ret) {
 992                 goto list_error;
 993         }
 994         return list_objd;
 995
 996 list_error:
 997         free(list);
 998 alloc_error:
 999         {
1000                 int err;
1001
1002                 err = lttng_ust_objd_unref(list_objd, 1);
1003                 assert(!err);
1004         }
1005 objd_error:
1006         return ret;
1007 }
1008
1009 static
1010 int lttng_release_tracepoint_list(int objd)
1011 {
1012         struct lttng_ust_tracepoint_list *list = objd_private(objd);
1013
1014         if (list) {
1015                 lttng_probes_prune_event_list(list);
1016                 free(list);
1017                 return 0;
1018         } else {
1019                 return -EINVAL;
1020         }
1021 }
1022
1023 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops = {
1024         .release = lttng_release_tracepoint_list,
1025         .cmd = lttng_tracepoint_list_cmd,
1026 };
1027
1028 static
1029 long lttng_tracepoint_field_list_cmd(int objd, unsigned int cmd,
1030         unsigned long arg, union ust_args *uargs, void *owner)
1031 {
1032         struct lttng_ust_field_list *list = objd_private(objd);
1033         struct lttng_ust_field_iter *tp = &uargs->field_list.entry;
1034         struct lttng_ust_field_iter *iter;
1035
1036         switch (cmd) {
1037         case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET:
1038         {
1039                 iter = lttng_ust_field_list_get_iter_next(list);
1040                 if (!iter)
1041                         return -LTTNG_UST_ERR_NOENT;
1042                 memcpy(tp, iter, sizeof(*tp));
1043                 return 0;
1044         }
1045         default:
1046                 return -EINVAL;
1047         }
1048 }
1049
1050 static
1051 int lttng_abi_tracepoint_field_list(void *owner)
1052 {
1053         int list_objd, ret;
1054         struct lttng_ust_field_list *list;
1055
1056         list_objd = objd_alloc(NULL, &lttng_tracepoint_field_list_ops, owner,
1057                         "tp_field_list");
1058         if (list_objd < 0) {
1059                 ret = list_objd;
1060                 goto objd_error;
1061         }
1062         list = zmalloc(sizeof(*list));
1063         if (!list) {
1064                 ret = -ENOMEM;
1065                 goto alloc_error;
1066         }
1067         objd_set_private(list_objd, list);
1068
1069         /* populate list by walking on all registered probes. */
1070         ret = lttng_probes_get_field_list(list);
1071         if (ret) {
1072                 goto list_error;
1073         }
1074         return list_objd;
1075
1076 list_error:
1077         free(list);
1078 alloc_error:
1079         {
1080                 int err;
1081
1082                 err = lttng_ust_objd_unref(list_objd, 1);
1083                 assert(!err);
1084         }
1085 objd_error:
1086         return ret;
1087 }
1088
1089 static
1090 int lttng_release_tracepoint_field_list(int objd)
1091 {
1092         struct lttng_ust_field_list *list = objd_private(objd);
1093
1094         if (list) {
1095                 lttng_probes_prune_field_list(list);
1096                 free(list);
1097                 return 0;
1098         } else {
1099                 return -EINVAL;
1100         }
1101 }
1102
1103 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops = {
1104         .release = lttng_release_tracepoint_field_list,
1105         .cmd = lttng_tracepoint_field_list_cmd,
1106 };
1107
1108 static
1109 int lttng_abi_map_stream(int channel_objd, struct lttng_ust_stream *info,
1110                 union ust_args *uargs, void *owner)
1111 {
1112         struct lttng_channel *channel = objd_private(channel_objd);
1113         int ret;
1114
1115         ret = channel_handle_add_stream(channel->handle,
1116                 uargs->stream.shm_fd, uargs->stream.wakeup_fd,
1117                 info->stream_nr, info->len);
1118         if (ret)
1119                 goto error_add_stream;
1120
1121         return 0;
1122
1123 error_add_stream:
1124         return ret;
1125 }
1126
1127 static
1128 int lttng_abi_create_event_enabler(int channel_objd,
1129                            struct lttng_ust_event *event_param,
1130                            void *owner,
1131                            enum lttng_enabler_format_type format_type)
1132 {
1133         struct lttng_channel *channel = objd_private(channel_objd);
1134         struct lttng_event_enabler *enabler;
1135         int event_objd, ret;
1136
1137         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1138         event_objd = objd_alloc(NULL, &lttng_event_enabler_ops, owner,
1139                 "event enabler");
1140         if (event_objd < 0) {
1141                 ret = event_objd;
1142                 goto objd_error;
1143         }
1144         /*
1145          * We tolerate no failure path after event creation. It will stay
1146          * invariant for the rest of the session.
1147          */
1148         enabler = lttng_event_enabler_create(format_type, event_param, channel);
1149         if (!enabler) {
1150                 ret = -ENOMEM;
1151                 goto event_error;
1152         }
1153         objd_set_private(event_objd, enabler);
1154         /* The event holds a reference on the channel */
1155         objd_ref(channel_objd);
1156         return event_objd;
1157
1158 event_error:
1159         {
1160                 int err;
1161
1162                 err = lttng_ust_objd_unref(event_objd, 1);
1163                 assert(!err);
1164         }
1165 objd_error:
1166         return ret;
1167 }
1168
1169 /**
1170  *      lttng_channel_cmd - lttng control through object descriptors
1171  *
1172  *      @objd: the object descriptor
1173  *      @cmd: the command
1174  *      @arg: command arg
1175  *      @uargs: UST arguments (internal)
1176  *      @owner: objd owner
1177  *
1178  *      This object descriptor implements lttng commands:
1179  *      LTTNG_UST_STREAM
1180  *              Returns an event stream object descriptor or failure.
1181  *              (typically, one event stream records events from one CPU)
1182  *      LTTNG_UST_EVENT
1183  *              Returns an event object descriptor or failure.
1184  *      LTTNG_UST_CONTEXT
1185  *              Prepend a context field to each event in the channel
1186  *      LTTNG_UST_ENABLE
1187  *              Enable recording for events in this channel (weak enable)
1188  *      LTTNG_UST_DISABLE
1189  *              Disable recording for events in this channel (strong disable)
1190  *
1191  * Channel and event file descriptors also hold a reference on the session.
1192  */
1193 static
1194 long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg,
1195         union ust_args *uargs, void *owner)
1196 {
1197         struct lttng_channel *channel = objd_private(objd);
1198
1199         if (cmd != LTTNG_UST_STREAM) {
1200                 /*
1201                  * Check if channel received all streams.
1202                  */
1203                 if (!lttng_is_channel_ready(channel))
1204                         return -EPERM;
1205         }
1206
1207         switch (cmd) {
1208         case LTTNG_UST_STREAM:
1209         {
1210                 struct lttng_ust_stream *stream;
1211
1212                 stream = (struct lttng_ust_stream *) arg;
1213                 /* stream used as output */
1214                 return lttng_abi_map_stream(objd, stream, uargs, owner);
1215         }
1216         case LTTNG_UST_EVENT:
1217         {
1218                 struct lttng_ust_event *event_param =
1219                         (struct lttng_ust_event *) arg;
1220
1221                 if (strutils_is_star_glob_pattern(event_param->name)) {
1222                         /*
1223                          * If the event name is a star globbing pattern,
1224                          * we create the special star globbing enabler.
1225                          */
1226                         return lttng_abi_create_event_enabler(objd, event_param,
1227                                         owner, LTTNG_ENABLER_FORMAT_STAR_GLOB);
1228                 } else {
1229                         return lttng_abi_create_event_enabler(objd, event_param,
1230                                         owner, LTTNG_ENABLER_FORMAT_EVENT);
1231                 }
1232         }
1233         case LTTNG_UST_CONTEXT:
1234                 return lttng_abi_add_context(objd,
1235                                 (struct lttng_ust_context *) arg, uargs,
1236                                 &channel->ctx, channel->session);
1237         case LTTNG_UST_ENABLE:
1238                 return lttng_channel_enable(channel);
1239         case LTTNG_UST_DISABLE:
1240                 return lttng_channel_disable(channel);
1241         case LTTNG_UST_FLUSH_BUFFER:
1242                 return channel->ops->flush_buffer(channel->chan, channel->handle);
1243         default:
1244                 return -EINVAL;
1245         }
1246 }
1247
1248 static
1249 int lttng_channel_release(int objd)
1250 {
1251         struct lttng_channel *channel = objd_private(objd);
1252
1253         if (channel)
1254                 return lttng_ust_objd_unref(channel->session->objd, 0);
1255         return 0;
1256 }
1257
1258 static const struct lttng_ust_objd_ops lttng_channel_ops = {
1259         .release = lttng_channel_release,
1260         .cmd = lttng_channel_cmd,
1261 };
1262
1263 /**
1264  *      lttng_enabler_cmd - lttng control through object descriptors
1265  *
1266  *      @objd: the object descriptor
1267  *      @cmd: the command
1268  *      @arg: command arg
1269  *      @uargs: UST arguments (internal)
1270  *      @owner: objd owner
1271  *
1272  *      This object descriptor implements lttng commands:
1273  *      LTTNG_UST_CONTEXT
1274  *              Prepend a context field to each record of events of this
1275  *              enabler.
1276  *      LTTNG_UST_ENABLE
1277  *              Enable recording for this enabler
1278  *      LTTNG_UST_DISABLE
1279  *              Disable recording for this enabler
1280  *      LTTNG_UST_FILTER
1281  *              Attach a filter to an enabler.
1282  *      LTTNG_UST_EXCLUSION
1283  *              Attach exclusions to an enabler.
1284  */
1285 static
1286 long lttng_event_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
1287         union ust_args *uargs, void *owner)
1288 {
1289         struct lttng_event_enabler *enabler = objd_private(objd);
1290
1291         switch (cmd) {
1292         case LTTNG_UST_CONTEXT:
1293                 return lttng_event_enabler_attach_context(enabler,
1294                                 (struct lttng_ust_context *) arg);
1295         case LTTNG_UST_ENABLE:
1296                 return lttng_event_enabler_enable(enabler);
1297         case LTTNG_UST_DISABLE:
1298                 return lttng_event_enabler_disable(enabler);
1299         case LTTNG_UST_FILTER:
1300         {
1301                 int ret;
1302
1303                 ret = lttng_event_enabler_attach_filter_bytecode(enabler,
1304                                 (struct lttng_ust_bytecode_node *) arg);
1305                 if (ret)
1306                         return ret;
1307                 return 0;
1308         }
1309         case LTTNG_UST_EXCLUSION:
1310         {
1311                 return lttng_event_enabler_attach_exclusion(enabler,
1312                                 (struct lttng_ust_excluder_node *) arg);
1313         }
1314         default:
1315                 return -EINVAL;
1316         }
1317 }
1318
1319 static
1320 int lttng_event_enabler_release(int objd)
1321 {
1322         struct lttng_event_enabler *event_enabler = objd_private(objd);
1323
1324         if (event_enabler)
1325                 return lttng_ust_objd_unref(event_enabler->chan->objd, 0);
1326
1327         return 0;
1328 }
1329
1330 static const struct lttng_ust_objd_ops lttng_event_enabler_ops = {
1331         .release = lttng_event_enabler_release,
1332         .cmd = lttng_event_enabler_cmd,
1333 };
1334
1335 void lttng_ust_abi_exit(void)
1336 {
1337         lttng_ust_abi_close_in_progress = 1;
1338         ust_lock_nocheck();
1339         objd_table_destroy();
1340         ust_unlock();
1341         lttng_ust_abi_close_in_progress = 0;
1342 }