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;
 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         /* Object descriptor takes ownership of notification fd. */
 382         *event_notifier_notif_fd = -1;
 383
 384         return event_notifier_group_objd;
 385
 386 objd_error:
 387         lttng_event_notifier_group_destroy(event_notifier_group);
 388 fd_error:
 389         return ret;
 390 }
 391
 392 static
 393 long lttng_abi_add_context(int objd,
 394         struct lttng_ust_context *context_param,
 395         union ust_args *uargs,
 396         struct lttng_ctx **ctx, struct lttng_session *session)
 397 {
 398         return lttng_attach_context(context_param, uargs, ctx, session);
 399 }
 400
 401 /**
 402  *      lttng_cmd - lttng control through socket commands
 403  *
 404  *      @objd: the object descriptor
 405  *      @cmd: the command
 406  *      @arg: command arg
 407  *      @uargs: UST arguments (internal)
 408  *      @owner: objd owner
 409  *
 410  *      This descriptor implements lttng commands:
 411  *      LTTNG_UST_SESSION
 412  *              Returns a LTTng trace session object descriptor
 413  *      LTTNG_UST_TRACER_VERSION
 414  *              Returns the LTTng kernel tracer version
 415  *      LTTNG_UST_TRACEPOINT_LIST
 416  *              Returns a file descriptor listing available tracepoints
 417  *      LTTNG_UST_TRACEPOINT_FIELD_LIST
 418  *              Returns a file descriptor listing available tracepoint fields
 419  *      LTTNG_UST_WAIT_QUIESCENT
 420  *              Returns after all previously running probes have completed
 421  *
 422  * The returned session will be deleted when its file descriptor is closed.
 423  */
 424 static
 425 long lttng_cmd(int objd, unsigned int cmd, unsigned long arg,
 426         union ust_args *uargs, void *owner)
 427 {
 428         switch (cmd) {
 429         case LTTNG_UST_SESSION:
 430                 return lttng_abi_create_session(owner);
 431         case LTTNG_UST_TRACER_VERSION:
 432                 return lttng_abi_tracer_version(objd,
 433                                 (struct lttng_ust_tracer_version *) arg);
 434         case LTTNG_UST_TRACEPOINT_LIST:
 435                 return lttng_abi_tracepoint_list(owner);
 436         case LTTNG_UST_TRACEPOINT_FIELD_LIST:
 437                 return lttng_abi_tracepoint_field_list(owner);
 438         case LTTNG_UST_WAIT_QUIESCENT:
 439                 lttng_ust_synchronize_trace();
 440                 return 0;
 441         case LTTNG_UST_EVENT_NOTIFIER_GROUP_CREATE:
 442                 return lttng_abi_event_notifier_send_fd(owner,
 443                         &uargs->event_notifier_handle.event_notifier_notif_fd);
 444         default:
 445                 return -EINVAL;
 446         }
 447 }
 448
 449 static const struct lttng_ust_objd_ops lttng_ops = {
 450         .cmd = lttng_cmd,
 451 };
 452
 453 static
 454 int lttng_abi_map_channel(int session_objd,
 455                 struct lttng_ust_channel *ust_chan,
 456                 union ust_args *uargs,
 457                 void *owner)
 458 {
 459         struct lttng_session *session = objd_private(session_objd);
 460         const char *transport_name;
 461         const struct lttng_transport *transport;
 462         const char *chan_name;
 463         int chan_objd;
 464         struct lttng_ust_shm_handle *channel_handle;
 465         struct lttng_channel *lttng_chan;
 466         struct channel *chan;
 467         struct lttng_ust_lib_ring_buffer_config *config;
 468         void *chan_data;
 469         int wakeup_fd;
 470         uint64_t len;
 471         int ret;
 472         enum lttng_ust_chan_type type;
 473
 474         chan_data = uargs->channel.chan_data;
 475         wakeup_fd = uargs->channel.wakeup_fd;
 476         len = ust_chan->len;
 477         type = ust_chan->type;
 478
 479         switch (type) {
 480         case LTTNG_UST_CHAN_PER_CPU:
 481                 break;
 482         default:
 483                 ret = -EINVAL;
 484                 goto invalid;
 485         }
 486
 487         if (session->been_active) {
 488                 ret = -EBUSY;
 489                 goto active;    /* Refuse to add channel to active session */
 490         }
 491
 492         channel_handle = channel_handle_create(chan_data, len, wakeup_fd);
 493         if (!channel_handle) {
 494                 ret = -EINVAL;
 495                 goto handle_error;
 496         }
 497
 498         /* Ownership of chan_data and wakeup_fd taken by channel handle. */
 499         uargs->channel.chan_data = NULL;
 500         uargs->channel.wakeup_fd = -1;
 501
 502         chan = shmp(channel_handle, channel_handle->chan);
 503         assert(chan);
 504         chan->handle = channel_handle;
 505         config = &chan->backend.config;
 506         lttng_chan = channel_get_private(chan);
 507         if (!lttng_chan) {
 508                 ret = -EINVAL;
 509                 goto alloc_error;
 510         }
 511
 512         /* Lookup transport name */
 513         switch (type) {
 514         case LTTNG_UST_CHAN_PER_CPU:
 515                 if (config->output == RING_BUFFER_MMAP) {
 516                         if (config->mode == RING_BUFFER_OVERWRITE) {
 517                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 518                                         transport_name = "relay-overwrite-mmap";
 519                                 } else {
 520                                         transport_name = "relay-overwrite-rt-mmap";
 521                                 }
 522                         } else {
 523                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 524                                         transport_name = "relay-discard-mmap";
 525                                 } else {
 526                                         transport_name = "relay-discard-rt-mmap";
 527                                 }
 528                         }
 529                 } else {
 530                         ret = -EINVAL;
 531                         goto notransport;
 532                 }
 533                 chan_name = "channel";
 534                 break;
 535         default:
 536                 ret = -EINVAL;
 537                 goto notransport;
 538         }
 539         transport = lttng_transport_find(transport_name);
 540         if (!transport) {
 541                 DBG("LTTng transport %s not found\n",
 542                        transport_name);
 543                 ret = -EINVAL;
 544                 goto notransport;
 545         }
 546
 547         chan_objd = objd_alloc(NULL, &lttng_channel_ops, owner, chan_name);
 548         if (chan_objd < 0) {
 549                 ret = chan_objd;
 550                 goto objd_error;
 551         }
 552
 553         /* Initialize our lttng chan */
 554         lttng_chan->chan = chan;
 555         lttng_chan->tstate = 1;
 556         lttng_chan->enabled = 1;
 557         lttng_chan->ctx = NULL;
 558         lttng_chan->session = session;
 559         lttng_chan->ops = &transport->ops;
 560         memcpy(&lttng_chan->chan->backend.config,
 561                 transport->client_config,
 562                 sizeof(lttng_chan->chan->backend.config));
 563         cds_list_add(&lttng_chan->node, &session->chan_head);
 564         lttng_chan->header_type = 0;
 565         lttng_chan->handle = channel_handle;
 566         lttng_chan->type = type;
 567
 568         /*
 569          * We tolerate no failure path after channel creation. It will stay
 570          * invariant for the rest of the session.
 571          */
 572         objd_set_private(chan_objd, lttng_chan);
 573         lttng_chan->objd = chan_objd;
 574         /* The channel created holds a reference on the session */
 575         objd_ref(session_objd);
 576         return chan_objd;
 577
 578         /* error path after channel was created */
 579 objd_error:
 580 notransport:
 581 alloc_error:
 582         channel_destroy(chan, channel_handle, 0);
 583         return ret;
 584
 585 handle_error:
 586 active:
 587 invalid:
 588         return ret;
 589 }
 590
 591 /**
 592  *      lttng_session_cmd - lttng session object command
 593  *
 594  *      @obj: the object
 595  *      @cmd: the command
 596  *      @arg: command arg
 597  *      @uargs: UST arguments (internal)
 598  *      @owner: objd owner
 599  *
 600  *      This descriptor implements lttng commands:
 601  *      LTTNG_UST_CHANNEL
 602  *              Returns a LTTng channel object descriptor
 603  *      LTTNG_UST_ENABLE
 604  *              Enables tracing for a session (weak enable)
 605  *      LTTNG_UST_DISABLE
 606  *              Disables tracing for a session (strong disable)
 607  *
 608  * The returned channel will be deleted when its file descriptor is closed.
 609  */
 610 static
 611 long lttng_session_cmd(int objd, unsigned int cmd, unsigned long arg,
 612         union ust_args *uargs, void *owner)
 613 {
 614         struct lttng_session *session = objd_private(objd);
 615
 616         switch (cmd) {
 617         case LTTNG_UST_CHANNEL:
 618                 return lttng_abi_map_channel(objd,
 619                                 (struct lttng_ust_channel *) arg,
 620                                 uargs, owner);
 621         case LTTNG_UST_SESSION_START:
 622         case LTTNG_UST_ENABLE:
 623                 return lttng_session_enable(session);
 624         case LTTNG_UST_SESSION_STOP:
 625         case LTTNG_UST_DISABLE:
 626                 return lttng_session_disable(session);
 627         case LTTNG_UST_SESSION_STATEDUMP:
 628                 return lttng_session_statedump(session);
 629         case LTTNG_UST_COUNTER:
 630         case LTTNG_UST_COUNTER_GLOBAL:
 631         case LTTNG_UST_COUNTER_CPU:
 632                 /* Not implemented yet. */
 633                 return -EINVAL;
 634         default:
 635                 return -EINVAL;
 636         }
 637 }
 638
 639 /*
 640  * Called when the last file reference is dropped.
 641  *
 642  * Big fat note: channels and events are invariant for the whole session after
 643  * their creation. So this session destruction also destroys all channel and
 644  * event structures specific to this session (they are not destroyed when their
 645  * individual file is released).
 646  */
 647 static
 648 int lttng_release_session(int objd)
 649 {
 650         struct lttng_session *session = objd_private(objd);
 651
 652         if (session) {
 653                 lttng_session_destroy(session);
 654                 return 0;
 655         } else {
 656                 return -EINVAL;
 657         }
 658 }
 659
 660 static const struct lttng_ust_objd_ops lttng_session_ops = {
 661         .release = lttng_release_session,
 662         .cmd = lttng_session_cmd,
 663 };
 664
 665 static int lttng_ust_event_notifier_enabler_create(int event_notifier_group_obj,
 666                 void *owner, struct lttng_ust_event_notifier *event_notifier_param,
 667                 enum lttng_enabler_format_type type)
 668 {
 669         struct lttng_event_notifier_group *event_notifier_group =
 670                 objd_private(event_notifier_group_obj);
 671         struct lttng_event_notifier_enabler *event_notifier_enabler;
 672         int event_notifier_objd, ret;
 673
 674         event_notifier_param->event.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 675         event_notifier_objd = objd_alloc(NULL, &lttng_event_notifier_enabler_ops, owner,
 676                 "event_notifier enabler");
 677         if (event_notifier_objd < 0) {
 678                 ret = event_notifier_objd;
 679                 goto objd_error;
 680         }
 681
 682         event_notifier_enabler = lttng_event_notifier_enabler_create(
 683                 event_notifier_group, type, event_notifier_param);
 684         if (!event_notifier_enabler) {
 685                 ret = -ENOMEM;
 686                 goto event_notifier_error;
 687         }
 688
 689         objd_set_private(event_notifier_objd, event_notifier_enabler);
 690         /* The event_notifier holds a reference on the event_notifier group. */
 691         objd_ref(event_notifier_enabler->group->objd);
 692
 693         return event_notifier_objd;
 694
 695 event_notifier_error:
 696         {
 697                 int err;
 698
 699                 err = lttng_ust_objd_unref(event_notifier_objd, 1);
 700                 assert(!err);
 701         }
 702 objd_error:
 703         return ret;
 704 }
 705
 706 static
 707 long lttng_event_notifier_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
 708                 union ust_args *uargs, void *owner)
 709 {
 710         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 711         switch (cmd) {
 712         case LTTNG_UST_FILTER:
 713                 return lttng_event_notifier_enabler_attach_filter_bytecode(
 714                         event_notifier_enabler,
 715                         (struct lttng_ust_bytecode_node **) arg);
 716         case LTTNG_UST_EXCLUSION:
 717                 return lttng_event_notifier_enabler_attach_exclusion(event_notifier_enabler,
 718                         (struct lttng_ust_excluder_node **) arg);
 719         case LTTNG_UST_CAPTURE:
 720                 return lttng_event_notifier_enabler_attach_capture_bytecode(
 721                         event_notifier_enabler,
 722                         (struct lttng_ust_bytecode_node **) arg);
 723         case LTTNG_UST_ENABLE:
 724                 return lttng_event_notifier_enabler_enable(event_notifier_enabler);
 725         case LTTNG_UST_DISABLE:
 726                 return lttng_event_notifier_enabler_disable(event_notifier_enabler);
 727         default:
 728                 return -EINVAL;
 729         }
 730 }
 731
 732 /**
 733  *      lttng_event_notifier_group_error_counter_cmd - lttng event_notifier group error counter object command
 734  *
 735  *      @obj: the object
 736  *      @cmd: the command
 737  *      @arg: command arg
 738  *      @uargs: UST arguments (internal)
 739  *      @owner: objd owner
 740  *
 741  *      This descriptor implements lttng commands:
 742  *      LTTNG_UST_COUNTER_GLOBAL
 743  *        Return negative error code on error, 0 on success.
 744  *      LTTNG_UST_COUNTER_CPU
 745  *        Return negative error code on error, 0 on success.
 746  */
 747 static
 748 long lttng_event_notifier_group_error_counter_cmd(int objd, unsigned int cmd, unsigned long arg,
 749         union ust_args *uargs, void *owner)
 750 {
 751         struct lttng_counter *counter = objd_private(objd);
 752
 753         switch (cmd) {
 754         case LTTNG_UST_COUNTER_GLOBAL:
 755                 return -EINVAL;         /* Unimplemented. */
 756         case LTTNG_UST_COUNTER_CPU:
 757         {
 758                 struct lttng_ust_counter_cpu *counter_cpu =
 759                         (struct lttng_ust_counter_cpu *)arg;
 760                 return lttng_counter_set_cpu_shm(counter->counter,
 761                         counter_cpu->cpu_nr, uargs->counter_shm.shm_fd);
 762         }
 763         default:
 764                 return -EINVAL;
 765         }
 766 }
 767
 768 LTTNG_HIDDEN
 769 int lttng_release_event_notifier_group_error_counter(int objd)
 770 {
 771         struct lttng_counter *counter = objd_private(objd);
 772
 773         if (counter) {
 774                 return lttng_ust_objd_unref(counter->event_notifier_group->objd, 0);
 775         } else {
 776                 return -EINVAL;
 777         }
 778 }
 779
 780 static const struct lttng_ust_objd_ops lttng_event_notifier_group_error_counter_ops = {
 781         .release = lttng_release_event_notifier_group_error_counter,
 782         .cmd = lttng_event_notifier_group_error_counter_cmd,
 783 };
 784
 785 static
 786 int lttng_ust_event_notifier_group_create_error_counter(int event_notifier_group_objd, void *owner,
 787                 struct lttng_ust_counter_conf *error_counter_conf)
 788 {
 789         const char *counter_transport_name;
 790         struct lttng_event_notifier_group *event_notifier_group =
 791                 objd_private(event_notifier_group_objd);
 792         struct lttng_counter *counter;
 793         int counter_objd, ret;
 794         struct lttng_counter_dimension dimensions[1];
 795         size_t counter_len;
 796
 797         if (event_notifier_group->error_counter)
 798                 return -EBUSY;
 799
 800         if (error_counter_conf->arithmetic != LTTNG_UST_COUNTER_ARITHMETIC_MODULAR)
 801                 return -EINVAL;
 802
 803         if (error_counter_conf->number_dimensions != 1)
 804                 return -EINVAL;
 805
 806         switch (error_counter_conf->bitness) {
 807         case LTTNG_UST_COUNTER_BITNESS_64:
 808                 counter_transport_name = "counter-per-cpu-64-modular";
 809                 break;
 810         case LTTNG_UST_COUNTER_BITNESS_32:
 811                 counter_transport_name = "counter-per-cpu-32-modular";
 812                 break;
 813         default:
 814                 return -EINVAL;
 815         }
 816
 817         counter_objd = objd_alloc(NULL, &lttng_event_notifier_group_error_counter_ops, owner,
 818                 "event_notifier group error counter");
 819         if (counter_objd < 0) {
 820                 ret = counter_objd;
 821                 goto objd_error;
 822         }
 823
 824         counter_len = error_counter_conf->dimensions[0].size;
 825         dimensions[0].size = counter_len;
 826         dimensions[0].underflow_index = 0;
 827         dimensions[0].overflow_index = 0;
 828         dimensions[0].has_underflow = 0;
 829         dimensions[0].has_overflow = 0;
 830
 831         counter = lttng_ust_counter_create(counter_transport_name, 1, dimensions);
 832         if (!counter) {
 833                 ret = -EINVAL;
 834                 goto create_error;
 835         }
 836
 837         event_notifier_group->error_counter_len = counter_len;
 838         /*
 839          * store-release to publish error counter matches load-acquire
 840          * in record_error. Ensures the counter is created and the
 841          * error_counter_len is set before they are used.
 842          * Currently a full memory barrier is used, which could be
 843          * turned into acquire-release barriers.
 844          */
 845         cmm_smp_mb();
 846         CMM_STORE_SHARED(event_notifier_group->error_counter, counter);
 847
 848         counter->objd = counter_objd;
 849         counter->event_notifier_group = event_notifier_group;   /* owner */
 850
 851         objd_set_private(counter_objd, counter);
 852         /* The error counter holds a reference on the event_notifier group. */
 853         objd_ref(event_notifier_group->objd);
 854
 855         return counter_objd;
 856
 857 create_error:
 858         {
 859                 int err;
 860
 861                 err = lttng_ust_objd_unref(counter_objd, 1);
 862                 assert(!err);
 863         }
 864 objd_error:
 865         return ret;
 866 }
 867
 868 static
 869 long lttng_event_notifier_group_cmd(int objd, unsigned int cmd, unsigned long arg,
 870                 union ust_args *uargs, void *owner)
 871 {
 872         switch (cmd) {
 873         case LTTNG_UST_EVENT_NOTIFIER_CREATE:
 874         {
 875                 struct lttng_ust_event_notifier *event_notifier_param =
 876                         (struct lttng_ust_event_notifier *) arg;
 877                 if (strutils_is_star_glob_pattern(event_notifier_param->event.name)) {
 878                         /*
 879                          * If the event name is a star globbing pattern,
 880                          * we create the special star globbing enabler.
 881                          */
 882                         return lttng_ust_event_notifier_enabler_create(objd,
 883                                         owner, event_notifier_param,
 884                                         LTTNG_ENABLER_FORMAT_STAR_GLOB);
 885                 } else {
 886                         return lttng_ust_event_notifier_enabler_create(objd,
 887                                         owner, event_notifier_param,
 888                                         LTTNG_ENABLER_FORMAT_EVENT);
 889                 }
 890         }
 891         case LTTNG_UST_COUNTER:
 892         {
 893                 struct lttng_ust_counter_conf *counter_conf =
 894                         (struct lttng_ust_counter_conf *) uargs->counter.counter_data;
 895                 return lttng_ust_event_notifier_group_create_error_counter(
 896                                 objd, owner, counter_conf);
 897         }
 898         default:
 899                 return -EINVAL;
 900         }
 901 }
 902
 903 static
 904 int lttng_event_notifier_enabler_release(int objd)
 905 {
 906         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 907
 908         if (event_notifier_enabler)
 909                 return lttng_ust_objd_unref(event_notifier_enabler->group->objd, 0);
 910         return 0;
 911 }
 912
 913 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops = {
 914         .release = lttng_event_notifier_enabler_release,
 915         .cmd = lttng_event_notifier_enabler_cmd,
 916 };
 917
 918 static
 919 int lttng_release_event_notifier_group(int objd)
 920 {
 921         struct lttng_event_notifier_group *event_notifier_group = objd_private(objd);
 922
 923         if (event_notifier_group) {
 924                 lttng_event_notifier_group_destroy(event_notifier_group);
 925                 return 0;
 926         } else {
 927                 return -EINVAL;
 928         }
 929 }
 930
 931 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops = {
 932         .release = lttng_release_event_notifier_group,
 933         .cmd = lttng_event_notifier_group_cmd,
 934 };
 935
 936 static
 937 long lttng_tracepoint_list_cmd(int objd, unsigned int cmd, unsigned long arg,
 938         union ust_args *uargs, void *owner)
 939 {
 940         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 941         struct lttng_ust_tracepoint_iter *tp =
 942                 (struct lttng_ust_tracepoint_iter *) arg;
 943         struct lttng_ust_tracepoint_iter *iter;
 944
 945         switch (cmd) {
 946         case LTTNG_UST_TRACEPOINT_LIST_GET:
 947         {
 948                 iter = lttng_ust_tracepoint_list_get_iter_next(list);
 949                 if (!iter)
 950                         return -LTTNG_UST_ERR_NOENT;
 951                 memcpy(tp, iter, sizeof(*tp));
 952                 return 0;
 953         }
 954         default:
 955                 return -EINVAL;
 956         }
 957 }
 958
 959 static
 960 int lttng_abi_tracepoint_list(void *owner)
 961 {
 962         int list_objd, ret;
 963         struct lttng_ust_tracepoint_list *list;
 964
 965         list_objd = objd_alloc(NULL, &lttng_tracepoint_list_ops, owner, "tp_list");
 966         if (list_objd < 0) {
 967                 ret = list_objd;
 968                 goto objd_error;
 969         }
 970         list = zmalloc(sizeof(*list));
 971         if (!list) {
 972                 ret = -ENOMEM;
 973                 goto alloc_error;
 974         }
 975         objd_set_private(list_objd, list);
 976
 977         /* populate list by walking on all registered probes. */
 978         ret = lttng_probes_get_event_list(list);
 979         if (ret) {
 980                 goto list_error;
 981         }
 982         return list_objd;
 983
 984 list_error:
 985         free(list);
 986 alloc_error:
 987         {
 988                 int err;
 989
 990                 err = lttng_ust_objd_unref(list_objd, 1);
 991                 assert(!err);
 992         }
 993 objd_error:
 994         return ret;
 995 }
 996
 997 static
 998 int lttng_release_tracepoint_list(int objd)
 999 {
1000         struct lttng_ust_tracepoint_list *list = objd_private(objd);
1001
1002         if (list) {
1003                 lttng_probes_prune_event_list(list);
1004                 free(list);
1005                 return 0;
1006         } else {
1007                 return -EINVAL;
1008         }
1009 }
1010
1011 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops = {
1012         .release = lttng_release_tracepoint_list,
1013         .cmd = lttng_tracepoint_list_cmd,
1014 };
1015
1016 static
1017 long lttng_tracepoint_field_list_cmd(int objd, unsigned int cmd,
1018         unsigned long arg, union ust_args *uargs, void *owner)
1019 {
1020         struct lttng_ust_field_list *list = objd_private(objd);
1021         struct lttng_ust_field_iter *tp = &uargs->field_list.entry;
1022         struct lttng_ust_field_iter *iter;
1023
1024         switch (cmd) {
1025         case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET:
1026         {
1027                 iter = lttng_ust_field_list_get_iter_next(list);
1028                 if (!iter)
1029                         return -LTTNG_UST_ERR_NOENT;
1030                 memcpy(tp, iter, sizeof(*tp));
1031                 return 0;
1032         }
1033         default:
1034                 return -EINVAL;
1035         }
1036 }
1037
1038 static
1039 int lttng_abi_tracepoint_field_list(void *owner)
1040 {
1041         int list_objd, ret;
1042         struct lttng_ust_field_list *list;
1043
1044         list_objd = objd_alloc(NULL, &lttng_tracepoint_field_list_ops, owner,
1045                         "tp_field_list");
1046         if (list_objd < 0) {
1047                 ret = list_objd;
1048                 goto objd_error;
1049         }
1050         list = zmalloc(sizeof(*list));
1051         if (!list) {
1052                 ret = -ENOMEM;
1053                 goto alloc_error;
1054         }
1055         objd_set_private(list_objd, list);
1056
1057         /* populate list by walking on all registered probes. */
1058         ret = lttng_probes_get_field_list(list);
1059         if (ret) {
1060                 goto list_error;
1061         }
1062         return list_objd;
1063
1064 list_error:
1065         free(list);
1066 alloc_error:
1067         {
1068                 int err;
1069
1070                 err = lttng_ust_objd_unref(list_objd, 1);
1071                 assert(!err);
1072         }
1073 objd_error:
1074         return ret;
1075 }
1076
1077 static
1078 int lttng_release_tracepoint_field_list(int objd)
1079 {
1080         struct lttng_ust_field_list *list = objd_private(objd);
1081
1082         if (list) {
1083                 lttng_probes_prune_field_list(list);
1084                 free(list);
1085                 return 0;
1086         } else {
1087                 return -EINVAL;
1088         }
1089 }
1090
1091 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops = {
1092         .release = lttng_release_tracepoint_field_list,
1093         .cmd = lttng_tracepoint_field_list_cmd,
1094 };
1095
1096 static
1097 int lttng_abi_map_stream(int channel_objd, struct lttng_ust_stream *info,
1098                 union ust_args *uargs, void *owner)
1099 {
1100         struct lttng_channel *channel = objd_private(channel_objd);
1101         int ret;
1102
1103         ret = channel_handle_add_stream(channel->handle,
1104                 uargs->stream.shm_fd, uargs->stream.wakeup_fd,
1105                 info->stream_nr, info->len);
1106         if (ret)
1107                 goto error_add_stream;
1108         /* Take ownership of shm_fd and wakeup_fd. */
1109         uargs->stream.shm_fd = -1;
1110         uargs->stream.wakeup_fd = -1;
1111
1112         return 0;
1113
1114 error_add_stream:
1115         return ret;
1116 }
1117
1118 static
1119 int lttng_abi_create_event_enabler(int channel_objd,
1120                            struct lttng_ust_event *event_param,
1121                            void *owner,
1122                            enum lttng_enabler_format_type format_type)
1123 {
1124         struct lttng_channel *channel = objd_private(channel_objd);
1125         struct lttng_event_enabler *enabler;
1126         int event_objd, ret;
1127
1128         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1129         event_objd = objd_alloc(NULL, &lttng_event_enabler_ops, owner,
1130                 "event enabler");
1131         if (event_objd < 0) {
1132                 ret = event_objd;
1133                 goto objd_error;
1134         }
1135         /*
1136          * We tolerate no failure path after event creation. It will stay
1137          * invariant for the rest of the session.
1138          */
1139         enabler = lttng_event_enabler_create(format_type, event_param, channel);
1140         if (!enabler) {
1141                 ret = -ENOMEM;
1142                 goto event_error;
1143         }
1144         objd_set_private(event_objd, enabler);
1145         /* The event holds a reference on the channel */
1146         objd_ref(channel_objd);
1147         return event_objd;
1148
1149 event_error:
1150         {
1151                 int err;
1152
1153                 err = lttng_ust_objd_unref(event_objd, 1);
1154                 assert(!err);
1155         }
1156 objd_error:
1157         return ret;
1158 }
1159
1160 /**
1161  *      lttng_channel_cmd - lttng control through object descriptors
1162  *
1163  *      @objd: the object descriptor
1164  *      @cmd: the command
1165  *      @arg: command arg
1166  *      @uargs: UST arguments (internal)
1167  *      @owner: objd owner
1168  *
1169  *      This object descriptor implements lttng commands:
1170  *      LTTNG_UST_STREAM
1171  *              Returns an event stream object descriptor or failure.
1172  *              (typically, one event stream records events from one CPU)
1173  *      LTTNG_UST_EVENT
1174  *              Returns an event object descriptor or failure.
1175  *      LTTNG_UST_CONTEXT
1176  *              Prepend a context field to each event in the channel
1177  *      LTTNG_UST_ENABLE
1178  *              Enable recording for events in this channel (weak enable)
1179  *      LTTNG_UST_DISABLE
1180  *              Disable recording for events in this channel (strong disable)
1181  *
1182  * Channel and event file descriptors also hold a reference on the session.
1183  */
1184 static
1185 long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg,
1186         union ust_args *uargs, void *owner)
1187 {
1188         struct lttng_channel *channel = objd_private(objd);
1189
1190         if (cmd != LTTNG_UST_STREAM) {
1191                 /*
1192                  * Check if channel received all streams.
1193                  */
1194                 if (!lttng_is_channel_ready(channel))
1195                         return -EPERM;
1196         }
1197
1198         switch (cmd) {
1199         case LTTNG_UST_STREAM:
1200         {
1201                 struct lttng_ust_stream *stream;
1202
1203                 stream = (struct lttng_ust_stream *) arg;
1204                 /* stream used as output */
1205                 return lttng_abi_map_stream(objd, stream, uargs, owner);
1206         }
1207         case LTTNG_UST_EVENT:
1208         {
1209                 struct lttng_ust_event *event_param =
1210                         (struct lttng_ust_event *) arg;
1211
1212                 if (strutils_is_star_glob_pattern(event_param->name)) {
1213                         /*
1214                          * If the event name is a star globbing pattern,
1215                          * we create the special star globbing enabler.
1216                          */
1217                         return lttng_abi_create_event_enabler(objd, event_param,
1218                                         owner, LTTNG_ENABLER_FORMAT_STAR_GLOB);
1219                 } else {
1220                         return lttng_abi_create_event_enabler(objd, event_param,
1221                                         owner, LTTNG_ENABLER_FORMAT_EVENT);
1222                 }
1223         }
1224         case LTTNG_UST_CONTEXT:
1225                 return lttng_abi_add_context(objd,
1226                                 (struct lttng_ust_context *) arg, uargs,
1227                                 &channel->ctx, channel->session);
1228         case LTTNG_UST_ENABLE:
1229                 return lttng_channel_enable(channel);
1230         case LTTNG_UST_DISABLE:
1231                 return lttng_channel_disable(channel);
1232         case LTTNG_UST_FLUSH_BUFFER:
1233                 return channel->ops->flush_buffer(channel->chan, channel->handle);
1234         default:
1235                 return -EINVAL;
1236         }
1237 }
1238
1239 static
1240 int lttng_channel_release(int objd)
1241 {
1242         struct lttng_channel *channel = objd_private(objd);
1243
1244         if (channel)
1245                 return lttng_ust_objd_unref(channel->session->objd, 0);
1246         return 0;
1247 }
1248
1249 static const struct lttng_ust_objd_ops lttng_channel_ops = {
1250         .release = lttng_channel_release,
1251         .cmd = lttng_channel_cmd,
1252 };
1253
1254 /**
1255  *      lttng_enabler_cmd - lttng control through object descriptors
1256  *
1257  *      @objd: the object descriptor
1258  *      @cmd: the command
1259  *      @arg: command arg
1260  *      @uargs: UST arguments (internal)
1261  *      @owner: objd owner
1262  *
1263  *      This object descriptor implements lttng commands:
1264  *      LTTNG_UST_CONTEXT
1265  *              Prepend a context field to each record of events of this
1266  *              enabler.
1267  *      LTTNG_UST_ENABLE
1268  *              Enable recording for this enabler
1269  *      LTTNG_UST_DISABLE
1270  *              Disable recording for this enabler
1271  *      LTTNG_UST_FILTER
1272  *              Attach a filter to an enabler.
1273  *      LTTNG_UST_EXCLUSION
1274  *              Attach exclusions to an enabler.
1275  */
1276 static
1277 long lttng_event_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
1278         union ust_args *uargs, void *owner)
1279 {
1280         struct lttng_event_enabler *enabler = objd_private(objd);
1281
1282         switch (cmd) {
1283         case LTTNG_UST_CONTEXT:
1284                 return lttng_event_enabler_attach_context(enabler,
1285                                 (struct lttng_ust_context *) arg);
1286         case LTTNG_UST_ENABLE:
1287                 return lttng_event_enabler_enable(enabler);
1288         case LTTNG_UST_DISABLE:
1289                 return lttng_event_enabler_disable(enabler);
1290         case LTTNG_UST_FILTER:
1291         {
1292                 int ret;
1293
1294                 ret = lttng_event_enabler_attach_filter_bytecode(enabler,
1295                                 (struct lttng_ust_bytecode_node **) arg);
1296                 if (ret)
1297                         return ret;
1298                 return 0;
1299         }
1300         case LTTNG_UST_EXCLUSION:
1301         {
1302                 return lttng_event_enabler_attach_exclusion(enabler,
1303                                 (struct lttng_ust_excluder_node **) arg);
1304         }
1305         default:
1306                 return -EINVAL;
1307         }
1308 }
1309
1310 static
1311 int lttng_event_enabler_release(int objd)
1312 {
1313         struct lttng_event_enabler *event_enabler = objd_private(objd);
1314
1315         if (event_enabler)
1316                 return lttng_ust_objd_unref(event_enabler->chan->objd, 0);
1317
1318         return 0;
1319 }
1320
1321 static const struct lttng_ust_objd_ops lttng_event_enabler_ops = {
1322         .release = lttng_event_enabler_release,
1323         .cmd = lttng_event_enabler_cmd,
1324 };
1325
1326 void lttng_ust_abi_exit(void)
1327 {
1328         lttng_ust_abi_close_in_progress = 1;
1329         ust_lock_nocheck();
1330         objd_table_destroy();
1331         ust_unlock();
1332         lttng_ust_abi_close_in_progress = 0;
1333 }