liblttng-ust/lttng-ust-abi.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng UST ABI
   7  *
   8  * Mimic system calls for:
   9  * - session creation, returns an object descriptor or failure.
  10  *   - channel creation, returns an object descriptor or failure.
  11  *     - Operates on a session object descriptor
  12  *     - Takes all channel options as parameters.
  13  *   - stream get, returns an object descriptor or failure.
  14  *     - Operates on a channel object descriptor.
  15  *   - stream notifier get, returns an object descriptor or failure.
  16  *     - Operates on a channel object descriptor.
  17  *   - event creation, returns an object descriptor or failure.
  18  *     - Operates on a channel object descriptor
  19  *     - Takes an event name as parameter
  20  *     - Takes an instrumentation source as parameter
  21  *       - e.g. tracepoints, dynamic_probes...
  22  *     - Takes instrumentation source specific arguments.
  23  */
  24
  25 #define _LGPL_SOURCE
  26 #include <fcntl.h>
  27 #include <stdint.h>
  28 #include <unistd.h>
  29
  30 #include <urcu/compiler.h>
  31 #include <urcu/list.h>
  32
  33 #include <helper.h>
  34 #include <lttng/tracepoint.h>
  35 #include <lttng/ust-abi.h>
  36 #include <lttng/ust-error.h>
  37 #include <lttng/ust-events.h>
  38 #include <lttng/ust-version.h>
  39 #include <ust-fd.h>
  40 #include <usterr-signal-safe.h>
  41
  42 #include "../libringbuffer/frontend_types.h"
  43 #include "../libringbuffer/shm.h"
  44 #include "../libcounter/counter.h"
  45 #include "tracepoint-internal.h"
  46 #include "lttng-tracer.h"
  47 #include "string-utils.h"
  48 #include "ust-events-internal.h"
  49
  50 #define OBJ_NAME_LEN    16
  51
  52 static int lttng_ust_abi_close_in_progress;
  53
  54 static
  55 int lttng_abi_tracepoint_list(void *owner);
  56 static
  57 int lttng_abi_tracepoint_field_list(void *owner);
  58
  59 /*
  60  * Object descriptor table. Should be protected from concurrent access
  61  * by the caller.
  62  */
  63
  64 struct lttng_ust_obj {
  65         union {
  66                 struct {
  67                         void *private_data;
  68                         const struct lttng_ust_objd_ops *ops;
  69                         int f_count;
  70                         int owner_ref;  /* has ref from owner */
  71                         void *owner;
  72                         char name[OBJ_NAME_LEN];
  73                 } s;
  74                 int freelist_next;      /* offset freelist. end is -1. */
  75         } u;
  76 };
  77
  78 struct lttng_ust_objd_table {
  79         struct lttng_ust_obj *array;
  80         unsigned int len, allocated_len;
  81         int freelist_head;              /* offset freelist head. end is -1 */
  82 };
  83
  84 static struct lttng_ust_objd_table objd_table = {
  85         .freelist_head = -1,
  86 };
  87
  88 static
  89 int objd_alloc(void *private_data, const struct lttng_ust_objd_ops *ops,
  90                 void *owner, const char *name)
  91 {
  92         struct lttng_ust_obj *obj;
  93
  94         if (objd_table.freelist_head != -1) {
  95                 obj = &objd_table.array[objd_table.freelist_head];
  96                 objd_table.freelist_head = obj->u.freelist_next;
  97                 goto end;
  98         }
  99
 100         if (objd_table.len >= objd_table.allocated_len) {
 101                 unsigned int new_allocated_len, old_allocated_len;
 102                 struct lttng_ust_obj *new_table, *old_table;
 103
 104                 old_allocated_len = objd_table.allocated_len;
 105                 old_table = objd_table.array;
 106                 if (!old_allocated_len)
 107                         new_allocated_len = 1;
 108                 else
 109                         new_allocated_len = old_allocated_len << 1;
 110                 new_table = zmalloc(sizeof(struct lttng_ust_obj) * new_allocated_len);
 111                 if (!new_table)
 112                         return -ENOMEM;
 113                 memcpy(new_table, old_table,
 114                        sizeof(struct lttng_ust_obj) * old_allocated_len);
 115                 free(old_table);
 116                 objd_table.array = new_table;
 117                 objd_table.allocated_len = new_allocated_len;
 118         }
 119         obj = &objd_table.array[objd_table.len];
 120         objd_table.len++;
 121 end:
 122         obj->u.s.private_data = private_data;
 123         obj->u.s.ops = ops;
 124         obj->u.s.f_count = 2;   /* count == 1 : object is allocated */
 125                                 /* count == 2 : allocated + hold ref */
 126         obj->u.s.owner_ref = 1; /* One owner reference */
 127         obj->u.s.owner = owner;
 128         strncpy(obj->u.s.name, name, OBJ_NAME_LEN);
 129         obj->u.s.name[OBJ_NAME_LEN - 1] = '\0';
 130         return obj - objd_table.array;
 131 }
 132
 133 static
 134 struct lttng_ust_obj *_objd_get(int id)
 135 {
 136         if (id >= objd_table.len)
 137                 return NULL;
 138         if (!objd_table.array[id].u.s.f_count)
 139                 return NULL;
 140         return &objd_table.array[id];
 141 }
 142
 143 static
 144 void *objd_private(int id)
 145 {
 146         struct lttng_ust_obj *obj = _objd_get(id);
 147         assert(obj);
 148         return obj->u.s.private_data;
 149 }
 150
 151 static
 152 void objd_set_private(int id, void *private_data)
 153 {
 154         struct lttng_ust_obj *obj = _objd_get(id);
 155         assert(obj);
 156         obj->u.s.private_data = private_data;
 157 }
 158
 159 const struct lttng_ust_objd_ops *objd_ops(int id)
 160 {
 161         struct lttng_ust_obj *obj = _objd_get(id);
 162
 163         if (!obj)
 164                 return NULL;
 165         return obj->u.s.ops;
 166 }
 167
 168 static
 169 void objd_free(int id)
 170 {
 171         struct lttng_ust_obj *obj = _objd_get(id);
 172
 173         assert(obj);
 174         obj->u.freelist_next = objd_table.freelist_head;
 175         objd_table.freelist_head = obj - objd_table.array;
 176         assert(obj->u.s.f_count == 1);
 177         obj->u.s.f_count = 0;   /* deallocated */
 178 }
 179
 180 static
 181 void objd_ref(int id)
 182 {
 183         struct lttng_ust_obj *obj = _objd_get(id);
 184         assert(obj != NULL);
 185         obj->u.s.f_count++;
 186 }
 187
 188 int lttng_ust_objd_unref(int id, int is_owner)
 189 {
 190         struct lttng_ust_obj *obj = _objd_get(id);
 191
 192         if (!obj)
 193                 return -EINVAL;
 194         if (obj->u.s.f_count == 1) {
 195                 ERR("Reference counting error\n");
 196                 return -EINVAL;
 197         }
 198         if (is_owner) {
 199                 if (!obj->u.s.owner_ref) {
 200                         ERR("Error decrementing owner reference");
 201                         return -EINVAL;
 202                 }
 203                 obj->u.s.owner_ref--;
 204         }
 205         if ((--obj->u.s.f_count) == 1) {
 206                 const struct lttng_ust_objd_ops *ops = objd_ops(id);
 207
 208                 if (ops->release)
 209                         ops->release(id);
 210                 objd_free(id);
 211         }
 212         return 0;
 213 }
 214
 215 static
 216 void objd_table_destroy(void)
 217 {
 218         int i;
 219
 220         for (i = 0; i < objd_table.allocated_len; i++) {
 221                 struct lttng_ust_obj *obj;
 222
 223                 obj = _objd_get(i);
 224                 if (!obj)
 225                         continue;
 226                 if (!obj->u.s.owner_ref)
 227                         continue;       /* only unref owner ref. */
 228                 (void) lttng_ust_objd_unref(i, 1);
 229         }
 230         free(objd_table.array);
 231         objd_table.array = NULL;
 232         objd_table.len = 0;
 233         objd_table.allocated_len = 0;
 234         objd_table.freelist_head = -1;
 235 }
 236
 237 const char *lttng_ust_obj_get_name(int id)
 238 {
 239         struct lttng_ust_obj *obj = _objd_get(id);
 240
 241         if (!obj)
 242                 return NULL;
 243         return obj->u.s.name;
 244 }
 245
 246 void lttng_ust_objd_table_owner_cleanup(void *owner)
 247 {
 248         int i;
 249
 250         for (i = 0; i < objd_table.allocated_len; i++) {
 251                 struct lttng_ust_obj *obj;
 252
 253                 obj = _objd_get(i);
 254                 if (!obj)
 255                         continue;
 256                 if (!obj->u.s.owner)
 257                         continue;       /* skip root handles */
 258                 if (!obj->u.s.owner_ref)
 259                         continue;       /* only unref owner ref. */
 260                 if (obj->u.s.owner == owner)
 261                         (void) lttng_ust_objd_unref(i, 1);
 262         }
 263 }
 264
 265 /*
 266  * This is LTTng's own personal way to create an ABI for sessiond.
 267  * We send commands over a socket.
 268  */
 269
 270 static const struct lttng_ust_objd_ops lttng_ops;
 271 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops;
 272 static const struct lttng_ust_objd_ops lttng_session_ops;
 273 static const struct lttng_ust_objd_ops lttng_channel_ops;
 274 static const struct lttng_ust_objd_ops lttng_event_enabler_ops;
 275 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops;
 276 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops;
 277 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops;
 278
 279 int lttng_abi_create_root_handle(void)
 280 {
 281         int root_handle;
 282
 283         /* root handles have NULL owners */
 284         root_handle = objd_alloc(NULL, &lttng_ops, NULL, "root");
 285         return root_handle;
 286 }
 287
 288 static
 289 int lttng_is_channel_ready(struct lttng_channel *lttng_chan)
 290 {
 291         struct channel *chan;
 292         unsigned int nr_streams, exp_streams;
 293
 294         chan = lttng_chan->chan;
 295         nr_streams = channel_handle_get_nr_streams(lttng_chan->handle);
 296         exp_streams = chan->nr_streams;
 297         return nr_streams == exp_streams;
 298 }
 299
 300 static
 301 int lttng_abi_create_session(void *owner)
 302 {
 303         struct lttng_session *session;
 304         int session_objd, ret;
 305
 306         session = lttng_session_create();
 307         if (!session)
 308                 return -ENOMEM;
 309         session_objd = objd_alloc(session, &lttng_session_ops, owner, "session");
 310         if (session_objd < 0) {
 311                 ret = session_objd;
 312                 goto objd_error;
 313         }
 314         session->objd = session_objd;
 315         session->owner = owner;
 316         return session_objd;
 317
 318 objd_error:
 319         lttng_session_destroy(session);
 320         return ret;
 321 }
 322
 323 static
 324 long lttng_abi_tracer_version(int objd,
 325         struct lttng_ust_tracer_version *v)
 326 {
 327         v->major = LTTNG_UST_MAJOR_VERSION;
 328         v->minor = LTTNG_UST_MINOR_VERSION;
 329         v->patchlevel = LTTNG_UST_PATCHLEVEL_VERSION;
 330         return 0;
 331 }
 332
 333 static
 334 int lttng_abi_event_notifier_send_fd(void *owner, int *event_notifier_notif_fd)
 335 {
 336         struct lttng_event_notifier_group *event_notifier_group;
 337         int event_notifier_group_objd, ret, fd_flag;
 338
 339         event_notifier_group = lttng_event_notifier_group_create();
 340         if (!event_notifier_group)
 341                 return -ENOMEM;
 342
 343         /*
 344          * Set this file descriptor as NON-BLOCKING.
 345          */
 346         fd_flag = fcntl(*event_notifier_notif_fd, F_GETFL);
 347
 348         fd_flag |= O_NONBLOCK;
 349
 350         ret = fcntl(*event_notifier_notif_fd, F_SETFL, fd_flag);
 351         if (ret) {
 352                 ret = -errno;
 353                 goto fd_error;
 354         }
 355
 356         event_notifier_group_objd = objd_alloc(event_notifier_group,
 357                 &lttng_event_notifier_group_ops, owner, "event_notifier_group");
 358         if (event_notifier_group_objd < 0) {
 359                 ret = event_notifier_group_objd;
 360                 goto objd_error;
 361         }
 362
 363         event_notifier_group->objd = event_notifier_group_objd;
 364         event_notifier_group->owner = owner;
 365         event_notifier_group->notification_fd = *event_notifier_notif_fd;
 366         /* Object descriptor takes ownership of notification fd. */
 367         *event_notifier_notif_fd = -1;
 368
 369         return event_notifier_group_objd;
 370
 371 objd_error:
 372         lttng_event_notifier_group_destroy(event_notifier_group);
 373 fd_error:
 374         return ret;
 375 }
 376
 377 static
 378 long lttng_abi_add_context(int objd,
 379         struct lttng_ust_context *context_param,
 380         union ust_args *uargs,
 381         struct lttng_ctx **ctx, struct lttng_session *session)
 382 {
 383         return lttng_attach_context(context_param, uargs, ctx, session);
 384 }
 385
 386 /**
 387  *      lttng_cmd - lttng control through socket commands
 388  *
 389  *      @objd: the object descriptor
 390  *      @cmd: the command
 391  *      @arg: command arg
 392  *      @uargs: UST arguments (internal)
 393  *      @owner: objd owner
 394  *
 395  *      This descriptor implements lttng commands:
 396  *      LTTNG_UST_SESSION
 397  *              Returns a LTTng trace session object descriptor
 398  *      LTTNG_UST_TRACER_VERSION
 399  *              Returns the LTTng kernel tracer version
 400  *      LTTNG_UST_TRACEPOINT_LIST
 401  *              Returns a file descriptor listing available tracepoints
 402  *      LTTNG_UST_TRACEPOINT_FIELD_LIST
 403  *              Returns a file descriptor listing available tracepoint fields
 404  *      LTTNG_UST_WAIT_QUIESCENT
 405  *              Returns after all previously running probes have completed
 406  *
 407  * The returned session will be deleted when its file descriptor is closed.
 408  */
 409 static
 410 long lttng_cmd(int objd, unsigned int cmd, unsigned long arg,
 411         union ust_args *uargs, void *owner)
 412 {
 413         switch (cmd) {
 414         case LTTNG_UST_SESSION:
 415                 return lttng_abi_create_session(owner);
 416         case LTTNG_UST_TRACER_VERSION:
 417                 return lttng_abi_tracer_version(objd,
 418                                 (struct lttng_ust_tracer_version *) arg);
 419         case LTTNG_UST_TRACEPOINT_LIST:
 420                 return lttng_abi_tracepoint_list(owner);
 421         case LTTNG_UST_TRACEPOINT_FIELD_LIST:
 422                 return lttng_abi_tracepoint_field_list(owner);
 423         case LTTNG_UST_WAIT_QUIESCENT:
 424                 lttng_ust_synchronize_trace();
 425                 return 0;
 426         case LTTNG_UST_EVENT_NOTIFIER_GROUP_CREATE:
 427                 return lttng_abi_event_notifier_send_fd(owner,
 428                         &uargs->event_notifier_handle.event_notifier_notif_fd);
 429         default:
 430                 return -EINVAL;
 431         }
 432 }
 433
 434 static const struct lttng_ust_objd_ops lttng_ops = {
 435         .cmd = lttng_cmd,
 436 };
 437
 438 static
 439 int lttng_abi_map_channel(int session_objd,
 440                 struct lttng_ust_channel *ust_chan,
 441                 union ust_args *uargs,
 442                 void *owner)
 443 {
 444         struct lttng_session *session = objd_private(session_objd);
 445         const char *transport_name;
 446         const struct lttng_transport *transport;
 447         const char *chan_name;
 448         int chan_objd;
 449         struct lttng_ust_shm_handle *channel_handle;
 450         struct lttng_channel *lttng_chan;
 451         struct channel *chan;
 452         struct lttng_ust_lib_ring_buffer_config *config;
 453         void *chan_data;
 454         int wakeup_fd;
 455         uint64_t len;
 456         int ret;
 457         enum lttng_ust_chan_type type;
 458
 459         chan_data = uargs->channel.chan_data;
 460         wakeup_fd = uargs->channel.wakeup_fd;
 461         len = ust_chan->len;
 462         type = ust_chan->type;
 463
 464         switch (type) {
 465         case LTTNG_UST_CHAN_PER_CPU:
 466                 break;
 467         default:
 468                 ret = -EINVAL;
 469                 goto invalid;
 470         }
 471
 472         if (session->been_active) {
 473                 ret = -EBUSY;
 474                 goto active;    /* Refuse to add channel to active session */
 475         }
 476
 477         channel_handle = channel_handle_create(chan_data, len, wakeup_fd);
 478         if (!channel_handle) {
 479                 ret = -EINVAL;
 480                 goto handle_error;
 481         }
 482
 483         /* Ownership of chan_data and wakeup_fd taken by channel handle. */
 484         uargs->channel.chan_data = NULL;
 485         uargs->channel.wakeup_fd = -1;
 486
 487         chan = shmp(channel_handle, channel_handle->chan);
 488         assert(chan);
 489         chan->handle = channel_handle;
 490         config = &chan->backend.config;
 491         lttng_chan = channel_get_private(chan);
 492         if (!lttng_chan) {
 493                 ret = -EINVAL;
 494                 goto alloc_error;
 495         }
 496
 497         /* Lookup transport name */
 498         switch (type) {
 499         case LTTNG_UST_CHAN_PER_CPU:
 500                 if (config->output == RING_BUFFER_MMAP) {
 501                         if (config->mode == RING_BUFFER_OVERWRITE) {
 502                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 503                                         transport_name = "relay-overwrite-mmap";
 504                                 } else {
 505                                         transport_name = "relay-overwrite-rt-mmap";
 506                                 }
 507                         } else {
 508                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 509                                         transport_name = "relay-discard-mmap";
 510                                 } else {
 511                                         transport_name = "relay-discard-rt-mmap";
 512                                 }
 513                         }
 514                 } else {
 515                         ret = -EINVAL;
 516                         goto notransport;
 517                 }
 518                 chan_name = "channel";
 519                 break;
 520         default:
 521                 ret = -EINVAL;
 522                 goto notransport;
 523         }
 524         transport = lttng_transport_find(transport_name);
 525         if (!transport) {
 526                 DBG("LTTng transport %s not found\n",
 527                        transport_name);
 528                 ret = -EINVAL;
 529                 goto notransport;
 530         }
 531
 532         chan_objd = objd_alloc(NULL, &lttng_channel_ops, owner, chan_name);
 533         if (chan_objd < 0) {
 534                 ret = chan_objd;
 535                 goto objd_error;
 536         }
 537
 538         /* Initialize our lttng chan */
 539         lttng_chan->chan = chan;
 540         lttng_chan->tstate = 1;
 541         lttng_chan->enabled = 1;
 542         lttng_chan->ctx = NULL;
 543         lttng_chan->session = session;
 544         lttng_chan->ops = &transport->ops;
 545         memcpy(&lttng_chan->chan->backend.config,
 546                 transport->client_config,
 547                 sizeof(lttng_chan->chan->backend.config));
 548         cds_list_add(&lttng_chan->node, &session->chan_head);
 549         lttng_chan->header_type = 0;
 550         lttng_chan->handle = channel_handle;
 551         lttng_chan->type = type;
 552
 553         /*
 554          * We tolerate no failure path after channel creation. It will stay
 555          * invariant for the rest of the session.
 556          */
 557         objd_set_private(chan_objd, lttng_chan);
 558         lttng_chan->objd = chan_objd;
 559         /* The channel created holds a reference on the session */
 560         objd_ref(session_objd);
 561         return chan_objd;
 562
 563         /* error path after channel was created */
 564 objd_error:
 565 notransport:
 566 alloc_error:
 567         channel_destroy(chan, channel_handle, 0);
 568         return ret;
 569
 570 handle_error:
 571 active:
 572 invalid:
 573         return ret;
 574 }
 575
 576 /**
 577  *      lttng_session_cmd - lttng session object command
 578  *
 579  *      @obj: the object
 580  *      @cmd: the command
 581  *      @arg: command arg
 582  *      @uargs: UST arguments (internal)
 583  *      @owner: objd owner
 584  *
 585  *      This descriptor implements lttng commands:
 586  *      LTTNG_UST_CHANNEL
 587  *              Returns a LTTng channel object descriptor
 588  *      LTTNG_UST_ENABLE
 589  *              Enables tracing for a session (weak enable)
 590  *      LTTNG_UST_DISABLE
 591  *              Disables tracing for a session (strong disable)
 592  *
 593  * The returned channel will be deleted when its file descriptor is closed.
 594  */
 595 static
 596 long lttng_session_cmd(int objd, unsigned int cmd, unsigned long arg,
 597         union ust_args *uargs, void *owner)
 598 {
 599         struct lttng_session *session = objd_private(objd);
 600
 601         switch (cmd) {
 602         case LTTNG_UST_CHANNEL:
 603                 return lttng_abi_map_channel(objd,
 604                                 (struct lttng_ust_channel *) arg,
 605                                 uargs, owner);
 606         case LTTNG_UST_SESSION_START:
 607         case LTTNG_UST_ENABLE:
 608                 return lttng_session_enable(session);
 609         case LTTNG_UST_SESSION_STOP:
 610         case LTTNG_UST_DISABLE:
 611                 return lttng_session_disable(session);
 612         case LTTNG_UST_SESSION_STATEDUMP:
 613                 return lttng_session_statedump(session);
 614         case LTTNG_UST_COUNTER:
 615         case LTTNG_UST_COUNTER_GLOBAL:
 616         case LTTNG_UST_COUNTER_CPU:
 617                 /* Not implemented yet. */
 618                 return -EINVAL;
 619         default:
 620                 return -EINVAL;
 621         }
 622 }
 623
 624 /*
 625  * Called when the last file reference is dropped.
 626  *
 627  * Big fat note: channels and events are invariant for the whole session after
 628  * their creation. So this session destruction also destroys all channel and
 629  * event structures specific to this session (they are not destroyed when their
 630  * individual file is released).
 631  */
 632 static
 633 int lttng_release_session(int objd)
 634 {
 635         struct lttng_session *session = objd_private(objd);
 636
 637         if (session) {
 638                 lttng_session_destroy(session);
 639                 return 0;
 640         } else {
 641                 return -EINVAL;
 642         }
 643 }
 644
 645 static const struct lttng_ust_objd_ops lttng_session_ops = {
 646         .release = lttng_release_session,
 647         .cmd = lttng_session_cmd,
 648 };
 649
 650 static int lttng_ust_event_notifier_enabler_create(int event_notifier_group_obj,
 651                 void *owner, struct lttng_ust_event_notifier *event_notifier_param,
 652                 enum lttng_enabler_format_type type)
 653 {
 654         struct lttng_event_notifier_group *event_notifier_group =
 655                 objd_private(event_notifier_group_obj);
 656         struct lttng_event_notifier_enabler *event_notifier_enabler;
 657         int event_notifier_objd, ret;
 658
 659         event_notifier_param->event.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 660         event_notifier_objd = objd_alloc(NULL, &lttng_event_notifier_enabler_ops, owner,
 661                 "event_notifier enabler");
 662         if (event_notifier_objd < 0) {
 663                 ret = event_notifier_objd;
 664                 goto objd_error;
 665         }
 666
 667         event_notifier_enabler = lttng_event_notifier_enabler_create(
 668                 event_notifier_group, type, event_notifier_param);
 669         if (!event_notifier_enabler) {
 670                 ret = -ENOMEM;
 671                 goto event_notifier_error;
 672         }
 673
 674         objd_set_private(event_notifier_objd, event_notifier_enabler);
 675         /* The event_notifier holds a reference on the event_notifier group. */
 676         objd_ref(event_notifier_enabler->group->objd);
 677
 678         return event_notifier_objd;
 679
 680 event_notifier_error:
 681         {
 682                 int err;
 683
 684                 err = lttng_ust_objd_unref(event_notifier_objd, 1);
 685                 assert(!err);
 686         }
 687 objd_error:
 688         return ret;
 689 }
 690
 691 static
 692 long lttng_event_notifier_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
 693                 union ust_args *uargs, void *owner)
 694 {
 695         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 696         switch (cmd) {
 697         case LTTNG_UST_FILTER:
 698                 return lttng_event_notifier_enabler_attach_filter_bytecode(
 699                         event_notifier_enabler,
 700                         (struct lttng_ust_bytecode_node **) arg);
 701         case LTTNG_UST_EXCLUSION:
 702                 return lttng_event_notifier_enabler_attach_exclusion(event_notifier_enabler,
 703                         (struct lttng_ust_excluder_node **) arg);
 704         case LTTNG_UST_CAPTURE:
 705                 return lttng_event_notifier_enabler_attach_capture_bytecode(
 706                         event_notifier_enabler,
 707                         (struct lttng_ust_bytecode_node **) arg);
 708         case LTTNG_UST_ENABLE:
 709                 return lttng_event_notifier_enabler_enable(event_notifier_enabler);
 710         case LTTNG_UST_DISABLE:
 711                 return lttng_event_notifier_enabler_disable(event_notifier_enabler);
 712         default:
 713                 return -EINVAL;
 714         }
 715 }
 716
 717 /**
 718  *      lttng_event_notifier_group_error_counter_cmd - lttng event_notifier group error counter object command
 719  *
 720  *      @obj: the object
 721  *      @cmd: the command
 722  *      @arg: command arg
 723  *      @uargs: UST arguments (internal)
 724  *      @owner: objd owner
 725  *
 726  *      This descriptor implements lttng commands:
 727  *      LTTNG_UST_COUNTER_GLOBAL
 728  *        Return negative error code on error, 0 on success.
 729  *      LTTNG_UST_COUNTER_CPU
 730  *        Return negative error code on error, 0 on success.
 731  */
 732 static
 733 long lttng_event_notifier_group_error_counter_cmd(int objd, unsigned int cmd, unsigned long arg,
 734         union ust_args *uargs, void *owner)
 735 {
 736         struct lttng_counter *counter = objd_private(objd);
 737
 738         switch (cmd) {
 739         case LTTNG_UST_COUNTER_GLOBAL:
 740                 return -EINVAL;         /* Unimplemented. */
 741         case LTTNG_UST_COUNTER_CPU:
 742         {
 743                 struct lttng_ust_counter_cpu *counter_cpu =
 744                         (struct lttng_ust_counter_cpu *)arg;
 745                 return lttng_counter_set_cpu_shm(counter->counter,
 746                         counter_cpu->cpu_nr, uargs->counter_shm.shm_fd);
 747         }
 748         default:
 749                 return -EINVAL;
 750         }
 751 }
 752
 753 LTTNG_HIDDEN
 754 int lttng_release_event_notifier_group_error_counter(int objd)
 755 {
 756         struct lttng_counter *counter = objd_private(objd);
 757
 758         if (counter) {
 759                 return lttng_ust_objd_unref(counter->event_notifier_group->objd, 0);
 760         } else {
 761                 return -EINVAL;
 762         }
 763 }
 764
 765 static const struct lttng_ust_objd_ops lttng_event_notifier_group_error_counter_ops = {
 766         .release = lttng_release_event_notifier_group_error_counter,
 767         .cmd = lttng_event_notifier_group_error_counter_cmd,
 768 };
 769
 770 static
 771 int lttng_ust_event_notifier_group_create_error_counter(int event_notifier_group_objd, void *owner,
 772                 struct lttng_ust_counter_conf *error_counter_conf)
 773 {
 774         const char *counter_transport_name;
 775         struct lttng_event_notifier_group *event_notifier_group =
 776                 objd_private(event_notifier_group_objd);
 777         struct lttng_counter *counter;
 778         int counter_objd, ret;
 779         struct lttng_counter_dimension dimensions[1];
 780         size_t counter_len;
 781
 782         if (event_notifier_group->error_counter)
 783                 return -EBUSY;
 784
 785         if (error_counter_conf->arithmetic != LTTNG_UST_COUNTER_ARITHMETIC_MODULAR)
 786                 return -EINVAL;
 787
 788         if (error_counter_conf->number_dimensions != 1)
 789                 return -EINVAL;
 790
 791         switch (error_counter_conf->bitness) {
 792         case LTTNG_UST_COUNTER_BITNESS_64:
 793                 counter_transport_name = "counter-per-cpu-64-modular";
 794                 break;
 795         case LTTNG_UST_COUNTER_BITNESS_32:
 796                 counter_transport_name = "counter-per-cpu-32-modular";
 797                 break;
 798         default:
 799                 return -EINVAL;
 800         }
 801
 802         counter_objd = objd_alloc(NULL, &lttng_event_notifier_group_error_counter_ops, owner,
 803                 "event_notifier group error counter");
 804         if (counter_objd < 0) {
 805                 ret = counter_objd;
 806                 goto objd_error;
 807         }
 808
 809         counter_len = error_counter_conf->dimensions[0].size;
 810         dimensions[0].size = counter_len;
 811         dimensions[0].underflow_index = 0;
 812         dimensions[0].overflow_index = 0;
 813         dimensions[0].has_underflow = 0;
 814         dimensions[0].has_overflow = 0;
 815
 816         counter = lttng_ust_counter_create(counter_transport_name, 1, dimensions);
 817         if (!counter) {
 818                 ret = -EINVAL;
 819                 goto create_error;
 820         }
 821
 822         event_notifier_group->error_counter_len = counter_len;
 823         /*
 824          * store-release to publish error counter matches load-acquire
 825          * in record_error. Ensures the counter is created and the
 826          * error_counter_len is set before they are used.
 827          * Currently a full memory barrier is used, which could be
 828          * turned into acquire-release barriers.
 829          */
 830         cmm_smp_mb();
 831         CMM_STORE_SHARED(event_notifier_group->error_counter, counter);
 832
 833         counter->objd = counter_objd;
 834         counter->event_notifier_group = event_notifier_group;   /* owner */
 835
 836         objd_set_private(counter_objd, counter);
 837         /* The error counter holds a reference on the event_notifier group. */
 838         objd_ref(event_notifier_group->objd);
 839
 840         return counter_objd;
 841
 842 create_error:
 843         {
 844                 int err;
 845
 846                 err = lttng_ust_objd_unref(counter_objd, 1);
 847                 assert(!err);
 848         }
 849 objd_error:
 850         return ret;
 851 }
 852
 853 static
 854 long lttng_event_notifier_group_cmd(int objd, unsigned int cmd, unsigned long arg,
 855                 union ust_args *uargs, void *owner)
 856 {
 857         switch (cmd) {
 858         case LTTNG_UST_EVENT_NOTIFIER_CREATE:
 859         {
 860                 struct lttng_ust_event_notifier *event_notifier_param =
 861                         (struct lttng_ust_event_notifier *) arg;
 862                 if (strutils_is_star_glob_pattern(event_notifier_param->event.name)) {
 863                         /*
 864                          * If the event name is a star globbing pattern,
 865                          * we create the special star globbing enabler.
 866                          */
 867                         return lttng_ust_event_notifier_enabler_create(objd,
 868                                         owner, event_notifier_param,
 869                                         LTTNG_ENABLER_FORMAT_STAR_GLOB);
 870                 } else {
 871                         return lttng_ust_event_notifier_enabler_create(objd,
 872                                         owner, event_notifier_param,
 873                                         LTTNG_ENABLER_FORMAT_EVENT);
 874                 }
 875         }
 876         case LTTNG_UST_COUNTER:
 877         {
 878                 struct lttng_ust_counter_conf *counter_conf =
 879                         (struct lttng_ust_counter_conf *) uargs->counter.counter_data;
 880                 return lttng_ust_event_notifier_group_create_error_counter(
 881                                 objd, owner, counter_conf);
 882         }
 883         default:
 884                 return -EINVAL;
 885         }
 886 }
 887
 888 static
 889 int lttng_event_notifier_enabler_release(int objd)
 890 {
 891         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 892
 893         if (event_notifier_enabler)
 894                 return lttng_ust_objd_unref(event_notifier_enabler->group->objd, 0);
 895         return 0;
 896 }
 897
 898 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops = {
 899         .release = lttng_event_notifier_enabler_release,
 900         .cmd = lttng_event_notifier_enabler_cmd,
 901 };
 902
 903 static
 904 int lttng_release_event_notifier_group(int objd)
 905 {
 906         struct lttng_event_notifier_group *event_notifier_group = objd_private(objd);
 907
 908         if (event_notifier_group) {
 909                 lttng_event_notifier_group_destroy(event_notifier_group);
 910                 return 0;
 911         } else {
 912                 return -EINVAL;
 913         }
 914 }
 915
 916 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops = {
 917         .release = lttng_release_event_notifier_group,
 918         .cmd = lttng_event_notifier_group_cmd,
 919 };
 920
 921 static
 922 long lttng_tracepoint_list_cmd(int objd, unsigned int cmd, unsigned long arg,
 923         union ust_args *uargs, void *owner)
 924 {
 925         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 926         struct lttng_ust_tracepoint_iter *tp =
 927                 (struct lttng_ust_tracepoint_iter *) arg;
 928         struct lttng_ust_tracepoint_iter *iter;
 929
 930         switch (cmd) {
 931         case LTTNG_UST_TRACEPOINT_LIST_GET:
 932         {
 933                 iter = lttng_ust_tracepoint_list_get_iter_next(list);
 934                 if (!iter)
 935                         return -LTTNG_UST_ERR_NOENT;
 936                 memcpy(tp, iter, sizeof(*tp));
 937                 return 0;
 938         }
 939         default:
 940                 return -EINVAL;
 941         }
 942 }
 943
 944 static
 945 int lttng_abi_tracepoint_list(void *owner)
 946 {
 947         int list_objd, ret;
 948         struct lttng_ust_tracepoint_list *list;
 949
 950         list_objd = objd_alloc(NULL, &lttng_tracepoint_list_ops, owner, "tp_list");
 951         if (list_objd < 0) {
 952                 ret = list_objd;
 953                 goto objd_error;
 954         }
 955         list = zmalloc(sizeof(*list));
 956         if (!list) {
 957                 ret = -ENOMEM;
 958                 goto alloc_error;
 959         }
 960         objd_set_private(list_objd, list);
 961
 962         /* populate list by walking on all registered probes. */
 963         ret = lttng_probes_get_event_list(list);
 964         if (ret) {
 965                 goto list_error;
 966         }
 967         return list_objd;
 968
 969 list_error:
 970         free(list);
 971 alloc_error:
 972         {
 973                 int err;
 974
 975                 err = lttng_ust_objd_unref(list_objd, 1);
 976                 assert(!err);
 977         }
 978 objd_error:
 979         return ret;
 980 }
 981
 982 static
 983 int lttng_release_tracepoint_list(int objd)
 984 {
 985         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 986
 987         if (list) {
 988                 lttng_probes_prune_event_list(list);
 989                 free(list);
 990                 return 0;
 991         } else {
 992                 return -EINVAL;
 993         }
 994 }
 995
 996 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops = {
 997         .release = lttng_release_tracepoint_list,
 998         .cmd = lttng_tracepoint_list_cmd,
 999 };
1000
1001 static
1002 long lttng_tracepoint_field_list_cmd(int objd, unsigned int cmd,
1003         unsigned long arg, union ust_args *uargs, void *owner)
1004 {
1005         struct lttng_ust_field_list *list = objd_private(objd);
1006         struct lttng_ust_field_iter *tp = &uargs->field_list.entry;
1007         struct lttng_ust_field_iter *iter;
1008
1009         switch (cmd) {
1010         case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET:
1011         {
1012                 iter = lttng_ust_field_list_get_iter_next(list);
1013                 if (!iter)
1014                         return -LTTNG_UST_ERR_NOENT;
1015                 memcpy(tp, iter, sizeof(*tp));
1016                 return 0;
1017         }
1018         default:
1019                 return -EINVAL;
1020         }
1021 }
1022
1023 static
1024 int lttng_abi_tracepoint_field_list(void *owner)
1025 {
1026         int list_objd, ret;
1027         struct lttng_ust_field_list *list;
1028
1029         list_objd = objd_alloc(NULL, &lttng_tracepoint_field_list_ops, owner,
1030                         "tp_field_list");
1031         if (list_objd < 0) {
1032                 ret = list_objd;
1033                 goto objd_error;
1034         }
1035         list = zmalloc(sizeof(*list));
1036         if (!list) {
1037                 ret = -ENOMEM;
1038                 goto alloc_error;
1039         }
1040         objd_set_private(list_objd, list);
1041
1042         /* populate list by walking on all registered probes. */
1043         ret = lttng_probes_get_field_list(list);
1044         if (ret) {
1045                 goto list_error;
1046         }
1047         return list_objd;
1048
1049 list_error:
1050         free(list);
1051 alloc_error:
1052         {
1053                 int err;
1054
1055                 err = lttng_ust_objd_unref(list_objd, 1);
1056                 assert(!err);
1057         }
1058 objd_error:
1059         return ret;
1060 }
1061
1062 static
1063 int lttng_release_tracepoint_field_list(int objd)
1064 {
1065         struct lttng_ust_field_list *list = objd_private(objd);
1066
1067         if (list) {
1068                 lttng_probes_prune_field_list(list);
1069                 free(list);
1070                 return 0;
1071         } else {
1072                 return -EINVAL;
1073         }
1074 }
1075
1076 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops = {
1077         .release = lttng_release_tracepoint_field_list,
1078         .cmd = lttng_tracepoint_field_list_cmd,
1079 };
1080
1081 static
1082 int lttng_abi_map_stream(int channel_objd, struct lttng_ust_stream *info,
1083                 union ust_args *uargs, void *owner)
1084 {
1085         struct lttng_channel *channel = objd_private(channel_objd);
1086         int ret;
1087
1088         ret = channel_handle_add_stream(channel->handle,
1089                 uargs->stream.shm_fd, uargs->stream.wakeup_fd,
1090                 info->stream_nr, info->len);
1091         if (ret)
1092                 goto error_add_stream;
1093         /* Take ownership of shm_fd and wakeup_fd. */
1094         uargs->stream.shm_fd = -1;
1095         uargs->stream.wakeup_fd = -1;
1096
1097         return 0;
1098
1099 error_add_stream:
1100         return ret;
1101 }
1102
1103 static
1104 int lttng_abi_create_event_enabler(int channel_objd,
1105                            struct lttng_ust_event *event_param,
1106                            void *owner,
1107                            enum lttng_enabler_format_type format_type)
1108 {
1109         struct lttng_channel *channel = objd_private(channel_objd);
1110         struct lttng_event_enabler *enabler;
1111         int event_objd, ret;
1112
1113         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1114         event_objd = objd_alloc(NULL, &lttng_event_enabler_ops, owner,
1115                 "event enabler");
1116         if (event_objd < 0) {
1117                 ret = event_objd;
1118                 goto objd_error;
1119         }
1120         /*
1121          * We tolerate no failure path after event creation. It will stay
1122          * invariant for the rest of the session.
1123          */
1124         enabler = lttng_event_enabler_create(format_type, event_param, channel);
1125         if (!enabler) {
1126                 ret = -ENOMEM;
1127                 goto event_error;
1128         }
1129         objd_set_private(event_objd, enabler);
1130         /* The event holds a reference on the channel */
1131         objd_ref(channel_objd);
1132         return event_objd;
1133
1134 event_error:
1135         {
1136                 int err;
1137
1138                 err = lttng_ust_objd_unref(event_objd, 1);
1139                 assert(!err);
1140         }
1141 objd_error:
1142         return ret;
1143 }
1144
1145 /**
1146  *      lttng_channel_cmd - lttng control through object descriptors
1147  *
1148  *      @objd: the object descriptor
1149  *      @cmd: the command
1150  *      @arg: command arg
1151  *      @uargs: UST arguments (internal)
1152  *      @owner: objd owner
1153  *
1154  *      This object descriptor implements lttng commands:
1155  *      LTTNG_UST_STREAM
1156  *              Returns an event stream object descriptor or failure.
1157  *              (typically, one event stream records events from one CPU)
1158  *      LTTNG_UST_EVENT
1159  *              Returns an event object descriptor or failure.
1160  *      LTTNG_UST_CONTEXT
1161  *              Prepend a context field to each event in the channel
1162  *      LTTNG_UST_ENABLE
1163  *              Enable recording for events in this channel (weak enable)
1164  *      LTTNG_UST_DISABLE
1165  *              Disable recording for events in this channel (strong disable)
1166  *
1167  * Channel and event file descriptors also hold a reference on the session.
1168  */
1169 static
1170 long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg,
1171         union ust_args *uargs, void *owner)
1172 {
1173         struct lttng_channel *channel = objd_private(objd);
1174
1175         if (cmd != LTTNG_UST_STREAM) {
1176                 /*
1177                  * Check if channel received all streams.
1178                  */
1179                 if (!lttng_is_channel_ready(channel))
1180                         return -EPERM;
1181         }
1182
1183         switch (cmd) {
1184         case LTTNG_UST_STREAM:
1185         {
1186                 struct lttng_ust_stream *stream;
1187
1188                 stream = (struct lttng_ust_stream *) arg;
1189                 /* stream used as output */
1190                 return lttng_abi_map_stream(objd, stream, uargs, owner);
1191         }
1192         case LTTNG_UST_EVENT:
1193         {
1194                 struct lttng_ust_event *event_param =
1195                         (struct lttng_ust_event *) arg;
1196
1197                 if (strutils_is_star_glob_pattern(event_param->name)) {
1198                         /*
1199                          * If the event name is a star globbing pattern,
1200                          * we create the special star globbing enabler.
1201                          */
1202                         return lttng_abi_create_event_enabler(objd, event_param,
1203                                         owner, LTTNG_ENABLER_FORMAT_STAR_GLOB);
1204                 } else {
1205                         return lttng_abi_create_event_enabler(objd, event_param,
1206                                         owner, LTTNG_ENABLER_FORMAT_EVENT);
1207                 }
1208         }
1209         case LTTNG_UST_CONTEXT:
1210                 return lttng_abi_add_context(objd,
1211                                 (struct lttng_ust_context *) arg, uargs,
1212                                 &channel->ctx, channel->session);
1213         case LTTNG_UST_ENABLE:
1214                 return lttng_channel_enable(channel);
1215         case LTTNG_UST_DISABLE:
1216                 return lttng_channel_disable(channel);
1217         case LTTNG_UST_FLUSH_BUFFER:
1218                 return channel->ops->flush_buffer(channel->chan, channel->handle);
1219         default:
1220                 return -EINVAL;
1221         }
1222 }
1223
1224 static
1225 int lttng_channel_release(int objd)
1226 {
1227         struct lttng_channel *channel = objd_private(objd);
1228
1229         if (channel)
1230                 return lttng_ust_objd_unref(channel->session->objd, 0);
1231         return 0;
1232 }
1233
1234 static const struct lttng_ust_objd_ops lttng_channel_ops = {
1235         .release = lttng_channel_release,
1236         .cmd = lttng_channel_cmd,
1237 };
1238
1239 /**
1240  *      lttng_enabler_cmd - lttng control through object descriptors
1241  *
1242  *      @objd: the object descriptor
1243  *      @cmd: the command
1244  *      @arg: command arg
1245  *      @uargs: UST arguments (internal)
1246  *      @owner: objd owner
1247  *
1248  *      This object descriptor implements lttng commands:
1249  *      LTTNG_UST_CONTEXT
1250  *              Prepend a context field to each record of events of this
1251  *              enabler.
1252  *      LTTNG_UST_ENABLE
1253  *              Enable recording for this enabler
1254  *      LTTNG_UST_DISABLE
1255  *              Disable recording for this enabler
1256  *      LTTNG_UST_FILTER
1257  *              Attach a filter to an enabler.
1258  *      LTTNG_UST_EXCLUSION
1259  *              Attach exclusions to an enabler.
1260  */
1261 static
1262 long lttng_event_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
1263         union ust_args *uargs, void *owner)
1264 {
1265         struct lttng_event_enabler *enabler = objd_private(objd);
1266
1267         switch (cmd) {
1268         case LTTNG_UST_CONTEXT:
1269                 return lttng_event_enabler_attach_context(enabler,
1270                                 (struct lttng_ust_context *) arg);
1271         case LTTNG_UST_ENABLE:
1272                 return lttng_event_enabler_enable(enabler);
1273         case LTTNG_UST_DISABLE:
1274                 return lttng_event_enabler_disable(enabler);
1275         case LTTNG_UST_FILTER:
1276         {
1277                 int ret;
1278
1279                 ret = lttng_event_enabler_attach_filter_bytecode(enabler,
1280                                 (struct lttng_ust_bytecode_node **) arg);
1281                 if (ret)
1282                         return ret;
1283                 return 0;
1284         }
1285         case LTTNG_UST_EXCLUSION:
1286         {
1287                 return lttng_event_enabler_attach_exclusion(enabler,
1288                                 (struct lttng_ust_excluder_node **) arg);
1289         }
1290         default:
1291                 return -EINVAL;
1292         }
1293 }
1294
1295 static
1296 int lttng_event_enabler_release(int objd)
1297 {
1298         struct lttng_event_enabler *event_enabler = objd_private(objd);
1299
1300         if (event_enabler)
1301                 return lttng_ust_objd_unref(event_enabler->chan->objd, 0);
1302
1303         return 0;
1304 }
1305
1306 static const struct lttng_ust_objd_ops lttng_event_enabler_ops = {
1307         .release = lttng_event_enabler_release,
1308         .cmd = lttng_event_enabler_cmd,
1309 };
1310
1311 void lttng_ust_abi_exit(void)
1312 {
1313         lttng_ust_abi_close_in_progress = 1;
1314         ust_lock_nocheck();
1315         objd_table_destroy();
1316         ust_unlock();
1317         lttng_ust_abi_close_in_progress = 0;
1318 }