liblttng-ust/lttng-ust-abi.c

   1 /*
   2  * lttng-ust-abi.c
   3  *
   4  * LTTng UST ABI
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  *
  23  * Mimic system calls for:
  24  * - session creation, returns an object descriptor or failure.
  25  *   - channel creation, returns an object descriptor or failure.
  26  *     - Operates on a session object descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns an object descriptor or failure.
  29  *     - Operates on a channel object descriptor.
  30  *   - stream notifier get, returns an object descriptor or failure.
  31  *     - Operates on a channel object descriptor.
  32  *   - event creation, returns an object descriptor or failure.
  33  *     - Operates on a channel object descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #define _LGPL_SOURCE
  41 #include <fcntl.h>
  42 #include <stdint.h>
  43 #include <unistd.h>
  44
  45 #include <urcu/compiler.h>
  46 #include <urcu/list.h>
  47
  48 #include <helper.h>
  49 #include <lttng/tracepoint.h>
  50 #include <lttng/ust-abi.h>
  51 #include <lttng/ust-error.h>
  52 #include <lttng/ust-events.h>
  53 #include <lttng/ust-version.h>
  54 #include <ust-fd.h>
  55 #include <usterr-signal-safe.h>
  56
  57 #include "../libringbuffer/frontend_types.h"
  58 #include "../libringbuffer/shm.h"
  59 #include "../libcounter/counter.h"
  60 #include "tracepoint-internal.h"
  61 #include "lttng-tracer.h"
  62 #include "string-utils.h"
  63 #include "ust-events-internal.h"
  64
  65 #define OBJ_NAME_LEN    16
  66
  67 static int lttng_ust_abi_close_in_progress;
  68
  69 static
  70 int lttng_abi_tracepoint_list(void *owner);
  71 static
  72 int lttng_abi_tracepoint_field_list(void *owner);
  73
  74 /*
  75  * Object descriptor table. Should be protected from concurrent access
  76  * by the caller.
  77  */
  78
  79 struct lttng_ust_obj {
  80         union {
  81                 struct {
  82                         void *private_data;
  83                         const struct lttng_ust_objd_ops *ops;
  84                         int f_count;
  85                         int owner_ref;  /* has ref from owner */
  86                         void *owner;
  87                         char name[OBJ_NAME_LEN];
  88                 } s;
  89                 int freelist_next;      /* offset freelist. end is -1. */
  90         } u;
  91 };
  92
  93 struct lttng_ust_objd_table {
  94         struct lttng_ust_obj *array;
  95         unsigned int len, allocated_len;
  96         int freelist_head;              /* offset freelist head. end is -1 */
  97 };
  98
  99 static struct lttng_ust_objd_table objd_table = {
 100         .freelist_head = -1,
 101 };
 102
 103 static
 104 int objd_alloc(void *private_data, const struct lttng_ust_objd_ops *ops,
 105                 void *owner, const char *name)
 106 {
 107         struct lttng_ust_obj *obj;
 108
 109         if (objd_table.freelist_head != -1) {
 110                 obj = &objd_table.array[objd_table.freelist_head];
 111                 objd_table.freelist_head = obj->u.freelist_next;
 112                 goto end;
 113         }
 114
 115         if (objd_table.len >= objd_table.allocated_len) {
 116                 unsigned int new_allocated_len, old_allocated_len;
 117                 struct lttng_ust_obj *new_table, *old_table;
 118
 119                 old_allocated_len = objd_table.allocated_len;
 120                 old_table = objd_table.array;
 121                 if (!old_allocated_len)
 122                         new_allocated_len = 1;
 123                 else
 124                         new_allocated_len = old_allocated_len << 1;
 125                 new_table = zmalloc(sizeof(struct lttng_ust_obj) * new_allocated_len);
 126                 if (!new_table)
 127                         return -ENOMEM;
 128                 memcpy(new_table, old_table,
 129                        sizeof(struct lttng_ust_obj) * old_allocated_len);
 130                 free(old_table);
 131                 objd_table.array = new_table;
 132                 objd_table.allocated_len = new_allocated_len;
 133         }
 134         obj = &objd_table.array[objd_table.len];
 135         objd_table.len++;
 136 end:
 137         obj->u.s.private_data = private_data;
 138         obj->u.s.ops = ops;
 139         obj->u.s.f_count = 2;   /* count == 1 : object is allocated */
 140                                 /* count == 2 : allocated + hold ref */
 141         obj->u.s.owner_ref = 1; /* One owner reference */
 142         obj->u.s.owner = owner;
 143         strncpy(obj->u.s.name, name, OBJ_NAME_LEN);
 144         obj->u.s.name[OBJ_NAME_LEN - 1] = '\0';
 145         return obj - objd_table.array;
 146 }
 147
 148 static
 149 struct lttng_ust_obj *_objd_get(int id)
 150 {
 151         if (id >= objd_table.len)
 152                 return NULL;
 153         if (!objd_table.array[id].u.s.f_count)
 154                 return NULL;
 155         return &objd_table.array[id];
 156 }
 157
 158 static
 159 void *objd_private(int id)
 160 {
 161         struct lttng_ust_obj *obj = _objd_get(id);
 162         assert(obj);
 163         return obj->u.s.private_data;
 164 }
 165
 166 static
 167 void objd_set_private(int id, void *private_data)
 168 {
 169         struct lttng_ust_obj *obj = _objd_get(id);
 170         assert(obj);
 171         obj->u.s.private_data = private_data;
 172 }
 173
 174 const struct lttng_ust_objd_ops *objd_ops(int id)
 175 {
 176         struct lttng_ust_obj *obj = _objd_get(id);
 177
 178         if (!obj)
 179                 return NULL;
 180         return obj->u.s.ops;
 181 }
 182
 183 static
 184 void objd_free(int id)
 185 {
 186         struct lttng_ust_obj *obj = _objd_get(id);
 187
 188         assert(obj);
 189         obj->u.freelist_next = objd_table.freelist_head;
 190         objd_table.freelist_head = obj - objd_table.array;
 191         assert(obj->u.s.f_count == 1);
 192         obj->u.s.f_count = 0;   /* deallocated */
 193 }
 194
 195 static
 196 void objd_ref(int id)
 197 {
 198         struct lttng_ust_obj *obj = _objd_get(id);
 199         assert(obj != NULL);
 200         obj->u.s.f_count++;
 201 }
 202
 203 int lttng_ust_objd_unref(int id, int is_owner)
 204 {
 205         struct lttng_ust_obj *obj = _objd_get(id);
 206
 207         if (!obj)
 208                 return -EINVAL;
 209         if (obj->u.s.f_count == 1) {
 210                 ERR("Reference counting error\n");
 211                 return -EINVAL;
 212         }
 213         if (is_owner) {
 214                 if (!obj->u.s.owner_ref) {
 215                         ERR("Error decrementing owner reference");
 216                         return -EINVAL;
 217                 }
 218                 obj->u.s.owner_ref--;
 219         }
 220         if ((--obj->u.s.f_count) == 1) {
 221                 const struct lttng_ust_objd_ops *ops = objd_ops(id);
 222
 223                 if (ops->release)
 224                         ops->release(id);
 225                 objd_free(id);
 226         }
 227         return 0;
 228 }
 229
 230 static
 231 void objd_table_destroy(void)
 232 {
 233         int i;
 234
 235         for (i = 0; i < objd_table.allocated_len; i++) {
 236                 struct lttng_ust_obj *obj;
 237
 238                 obj = _objd_get(i);
 239                 if (!obj)
 240                         continue;
 241                 if (!obj->u.s.owner_ref)
 242                         continue;       /* only unref owner ref. */
 243                 (void) lttng_ust_objd_unref(i, 1);
 244         }
 245         free(objd_table.array);
 246         objd_table.array = NULL;
 247         objd_table.len = 0;
 248         objd_table.allocated_len = 0;
 249         objd_table.freelist_head = -1;
 250 }
 251
 252 const char *lttng_ust_obj_get_name(int id)
 253 {
 254         struct lttng_ust_obj *obj = _objd_get(id);
 255
 256         if (!obj)
 257                 return NULL;
 258         return obj->u.s.name;
 259 }
 260
 261 void lttng_ust_objd_table_owner_cleanup(void *owner)
 262 {
 263         int i;
 264
 265         for (i = 0; i < objd_table.allocated_len; i++) {
 266                 struct lttng_ust_obj *obj;
 267
 268                 obj = _objd_get(i);
 269                 if (!obj)
 270                         continue;
 271                 if (!obj->u.s.owner)
 272                         continue;       /* skip root handles */
 273                 if (!obj->u.s.owner_ref)
 274                         continue;       /* only unref owner ref. */
 275                 if (obj->u.s.owner == owner)
 276                         (void) lttng_ust_objd_unref(i, 1);
 277         }
 278 }
 279
 280 /*
 281  * This is LTTng's own personal way to create an ABI for sessiond.
 282  * We send commands over a socket.
 283  */
 284
 285 static const struct lttng_ust_objd_ops lttng_ops;
 286 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops;
 287 static const struct lttng_ust_objd_ops lttng_session_ops;
 288 static const struct lttng_ust_objd_ops lttng_channel_ops;
 289 static const struct lttng_ust_objd_ops lttng_event_enabler_ops;
 290 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops;
 291 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops;
 292 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops;
 293
 294 int lttng_abi_create_root_handle(void)
 295 {
 296         int root_handle;
 297
 298         /* root handles have NULL owners */
 299         root_handle = objd_alloc(NULL, &lttng_ops, NULL, "root");
 300         return root_handle;
 301 }
 302
 303 static
 304 int lttng_is_channel_ready(struct lttng_channel *lttng_chan)
 305 {
 306         struct channel *chan;
 307         unsigned int nr_streams, exp_streams;
 308
 309         chan = lttng_chan->chan;
 310         nr_streams = channel_handle_get_nr_streams(lttng_chan->handle);
 311         exp_streams = chan->nr_streams;
 312         return nr_streams == exp_streams;
 313 }
 314
 315 static
 316 int lttng_abi_create_session(void *owner)
 317 {
 318         struct lttng_session *session;
 319         int session_objd, ret;
 320
 321         session = lttng_session_create();
 322         if (!session)
 323                 return -ENOMEM;
 324         session_objd = objd_alloc(session, &lttng_session_ops, owner, "session");
 325         if (session_objd < 0) {
 326                 ret = session_objd;
 327                 goto objd_error;
 328         }
 329         session->objd = session_objd;
 330         session->owner = owner;
 331         return session_objd;
 332
 333 objd_error:
 334         lttng_session_destroy(session);
 335         return ret;
 336 }
 337
 338 static
 339 long lttng_abi_tracer_version(int objd,
 340         struct lttng_ust_tracer_version *v)
 341 {
 342         v->major = LTTNG_UST_MAJOR_VERSION;
 343         v->minor = LTTNG_UST_MINOR_VERSION;
 344         v->patchlevel = LTTNG_UST_PATCHLEVEL_VERSION;
 345         return 0;
 346 }
 347
 348 static
 349 int lttng_abi_event_notifier_send_fd(void *owner, int event_notifier_notif_fd)
 350 {
 351         struct lttng_event_notifier_group *event_notifier_group;
 352         int event_notifier_group_objd, ret, fd_flag, close_ret;
 353
 354         event_notifier_group = lttng_event_notifier_group_create();
 355         if (!event_notifier_group)
 356                 return -ENOMEM;
 357
 358         /*
 359          * Set this file descriptor as NON-BLOCKING.
 360          */
 361         fd_flag = fcntl(event_notifier_notif_fd, F_GETFL);
 362
 363         fd_flag |= O_NONBLOCK;
 364
 365         ret = fcntl(event_notifier_notif_fd, F_SETFL, fd_flag);
 366         if (ret) {
 367                 ret = -errno;
 368                 goto fd_error;
 369         }
 370
 371         event_notifier_group_objd = objd_alloc(event_notifier_group,
 372                 &lttng_event_notifier_group_ops, owner, "event_notifier_group");
 373         if (event_notifier_group_objd < 0) {
 374                 ret = event_notifier_group_objd;
 375                 goto objd_error;
 376         }
 377
 378         event_notifier_group->objd = event_notifier_group_objd;
 379         event_notifier_group->owner = owner;
 380         event_notifier_group->notification_fd = event_notifier_notif_fd;
 381
 382         return event_notifier_group_objd;
 383
 384 objd_error:
 385         lttng_event_notifier_group_destroy(event_notifier_group);
 386 fd_error:
 387         close_ret = close(event_notifier_notif_fd);
 388         if (close_ret) {
 389                 PERROR("close");
 390         }
 391
 392         return ret;
 393 }
 394
 395 static
 396 long lttng_abi_add_context(int objd,
 397         struct lttng_ust_context *context_param,
 398         union ust_args *uargs,
 399         struct lttng_ctx **ctx, struct lttng_session *session)
 400 {
 401         return lttng_attach_context(context_param, uargs, ctx, session);
 402 }
 403
 404 /**
 405  *      lttng_cmd - lttng control through socket commands
 406  *
 407  *      @objd: the object descriptor
 408  *      @cmd: the command
 409  *      @arg: command arg
 410  *      @uargs: UST arguments (internal)
 411  *      @owner: objd owner
 412  *
 413  *      This descriptor implements lttng commands:
 414  *      LTTNG_UST_SESSION
 415  *              Returns a LTTng trace session object descriptor
 416  *      LTTNG_UST_TRACER_VERSION
 417  *              Returns the LTTng kernel tracer version
 418  *      LTTNG_UST_TRACEPOINT_LIST
 419  *              Returns a file descriptor listing available tracepoints
 420  *      LTTNG_UST_TRACEPOINT_FIELD_LIST
 421  *              Returns a file descriptor listing available tracepoint fields
 422  *      LTTNG_UST_WAIT_QUIESCENT
 423  *              Returns after all previously running probes have completed
 424  *
 425  * The returned session will be deleted when its file descriptor is closed.
 426  */
 427 static
 428 long lttng_cmd(int objd, unsigned int cmd, unsigned long arg,
 429         union ust_args *uargs, void *owner)
 430 {
 431         switch (cmd) {
 432         case LTTNG_UST_SESSION:
 433                 return lttng_abi_create_session(owner);
 434         case LTTNG_UST_TRACER_VERSION:
 435                 return lttng_abi_tracer_version(objd,
 436                                 (struct lttng_ust_tracer_version *) arg);
 437         case LTTNG_UST_TRACEPOINT_LIST:
 438                 return lttng_abi_tracepoint_list(owner);
 439         case LTTNG_UST_TRACEPOINT_FIELD_LIST:
 440                 return lttng_abi_tracepoint_field_list(owner);
 441         case LTTNG_UST_WAIT_QUIESCENT:
 442                 lttng_ust_synchronize_trace();
 443                 return 0;
 444         case LTTNG_UST_EVENT_NOTIFIER_GROUP_CREATE:
 445                 return lttng_abi_event_notifier_send_fd(owner,
 446                         uargs->event_notifier_handle.event_notifier_notif_fd);
 447         default:
 448                 return -EINVAL;
 449         }
 450 }
 451
 452 static const struct lttng_ust_objd_ops lttng_ops = {
 453         .cmd = lttng_cmd,
 454 };
 455
 456 static
 457 int lttng_abi_map_channel(int session_objd,
 458                 struct lttng_ust_channel *ust_chan,
 459                 union ust_args *uargs,
 460                 void *owner)
 461 {
 462         struct lttng_session *session = objd_private(session_objd);
 463         const char *transport_name;
 464         const struct lttng_transport *transport;
 465         const char *chan_name;
 466         int chan_objd;
 467         struct lttng_ust_shm_handle *channel_handle;
 468         struct lttng_channel *lttng_chan;
 469         struct channel *chan;
 470         struct lttng_ust_lib_ring_buffer_config *config;
 471         void *chan_data;
 472         int wakeup_fd;
 473         uint64_t len;
 474         int ret;
 475         enum lttng_ust_chan_type type;
 476
 477         chan_data = uargs->channel.chan_data;
 478         wakeup_fd = uargs->channel.wakeup_fd;
 479         len = ust_chan->len;
 480         type = ust_chan->type;
 481
 482         switch (type) {
 483         case LTTNG_UST_CHAN_PER_CPU:
 484                 break;
 485         default:
 486                 ret = -EINVAL;
 487                 goto invalid;
 488         }
 489
 490         if (session->been_active) {
 491                 ret = -EBUSY;
 492                 goto active;    /* Refuse to add channel to active session */
 493         }
 494
 495         channel_handle = channel_handle_create(chan_data, len, wakeup_fd);
 496         if (!channel_handle) {
 497                 ret = -EINVAL;
 498                 goto handle_error;
 499         }
 500
 501         /* Ownership of chan_data and wakeup_fd taken by channel handle. */
 502         uargs->channel.chan_data = NULL;
 503         uargs->channel.wakeup_fd = -1;
 504
 505         chan = shmp(channel_handle, channel_handle->chan);
 506         assert(chan);
 507         chan->handle = channel_handle;
 508         config = &chan->backend.config;
 509         lttng_chan = channel_get_private(chan);
 510         if (!lttng_chan) {
 511                 ret = -EINVAL;
 512                 goto alloc_error;
 513         }
 514
 515         /* Lookup transport name */
 516         switch (type) {
 517         case LTTNG_UST_CHAN_PER_CPU:
 518                 if (config->output == RING_BUFFER_MMAP) {
 519                         if (config->mode == RING_BUFFER_OVERWRITE) {
 520                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 521                                         transport_name = "relay-overwrite-mmap";
 522                                 } else {
 523                                         transport_name = "relay-overwrite-rt-mmap";
 524                                 }
 525                         } else {
 526                                 if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER) {
 527                                         transport_name = "relay-discard-mmap";
 528                                 } else {
 529                                         transport_name = "relay-discard-rt-mmap";
 530                                 }
 531                         }
 532                 } else {
 533                         ret = -EINVAL;
 534                         goto notransport;
 535                 }
 536                 chan_name = "channel";
 537                 break;
 538         default:
 539                 ret = -EINVAL;
 540                 goto notransport;
 541         }
 542         transport = lttng_transport_find(transport_name);
 543         if (!transport) {
 544                 DBG("LTTng transport %s not found\n",
 545                        transport_name);
 546                 ret = -EINVAL;
 547                 goto notransport;
 548         }
 549
 550         chan_objd = objd_alloc(NULL, &lttng_channel_ops, owner, chan_name);
 551         if (chan_objd < 0) {
 552                 ret = chan_objd;
 553                 goto objd_error;
 554         }
 555
 556         /* Initialize our lttng chan */
 557         lttng_chan->chan = chan;
 558         lttng_chan->tstate = 1;
 559         lttng_chan->enabled = 1;
 560         lttng_chan->ctx = NULL;
 561         lttng_chan->session = session;
 562         lttng_chan->ops = &transport->ops;
 563         memcpy(&lttng_chan->chan->backend.config,
 564                 transport->client_config,
 565                 sizeof(lttng_chan->chan->backend.config));
 566         cds_list_add(&lttng_chan->node, &session->chan_head);
 567         lttng_chan->header_type = 0;
 568         lttng_chan->handle = channel_handle;
 569         lttng_chan->type = type;
 570
 571         /*
 572          * We tolerate no failure path after channel creation. It will stay
 573          * invariant for the rest of the session.
 574          */
 575         objd_set_private(chan_objd, lttng_chan);
 576         lttng_chan->objd = chan_objd;
 577         /* The channel created holds a reference on the session */
 578         objd_ref(session_objd);
 579         return chan_objd;
 580
 581         /* error path after channel was created */
 582 objd_error:
 583 notransport:
 584 alloc_error:
 585         channel_destroy(chan, channel_handle, 0);
 586         return ret;
 587
 588 handle_error:
 589 active:
 590 invalid:
 591         return ret;
 592 }
 593
 594 /**
 595  *      lttng_session_cmd - lttng session object command
 596  *
 597  *      @obj: the object
 598  *      @cmd: the command
 599  *      @arg: command arg
 600  *      @uargs: UST arguments (internal)
 601  *      @owner: objd owner
 602  *
 603  *      This descriptor implements lttng commands:
 604  *      LTTNG_UST_CHANNEL
 605  *              Returns a LTTng channel object descriptor
 606  *      LTTNG_UST_ENABLE
 607  *              Enables tracing for a session (weak enable)
 608  *      LTTNG_UST_DISABLE
 609  *              Disables tracing for a session (strong disable)
 610  *
 611  * The returned channel will be deleted when its file descriptor is closed.
 612  */
 613 static
 614 long lttng_session_cmd(int objd, unsigned int cmd, unsigned long arg,
 615         union ust_args *uargs, void *owner)
 616 {
 617         struct lttng_session *session = objd_private(objd);
 618
 619         switch (cmd) {
 620         case LTTNG_UST_CHANNEL:
 621                 return lttng_abi_map_channel(objd,
 622                                 (struct lttng_ust_channel *) arg,
 623                                 uargs, owner);
 624         case LTTNG_UST_SESSION_START:
 625         case LTTNG_UST_ENABLE:
 626                 return lttng_session_enable(session);
 627         case LTTNG_UST_SESSION_STOP:
 628         case LTTNG_UST_DISABLE:
 629                 return lttng_session_disable(session);
 630         case LTTNG_UST_SESSION_STATEDUMP:
 631                 return lttng_session_statedump(session);
 632         case LTTNG_UST_COUNTER:
 633         case LTTNG_UST_COUNTER_GLOBAL:
 634         case LTTNG_UST_COUNTER_CPU:
 635                 /* Not implemented yet. */
 636                 return -EINVAL;
 637         default:
 638                 return -EINVAL;
 639         }
 640 }
 641
 642 /*
 643  * Called when the last file reference is dropped.
 644  *
 645  * Big fat note: channels and events are invariant for the whole session after
 646  * their creation. So this session destruction also destroys all channel and
 647  * event structures specific to this session (they are not destroyed when their
 648  * individual file is released).
 649  */
 650 static
 651 int lttng_release_session(int objd)
 652 {
 653         struct lttng_session *session = objd_private(objd);
 654
 655         if (session) {
 656                 lttng_session_destroy(session);
 657                 return 0;
 658         } else {
 659                 return -EINVAL;
 660         }
 661 }
 662
 663 static const struct lttng_ust_objd_ops lttng_session_ops = {
 664         .release = lttng_release_session,
 665         .cmd = lttng_session_cmd,
 666 };
 667
 668 static int lttng_ust_event_notifier_enabler_create(int event_notifier_group_obj,
 669                 void *owner, struct lttng_ust_event_notifier *event_notifier_param,
 670                 enum lttng_enabler_format_type type)
 671 {
 672         struct lttng_event_notifier_group *event_notifier_group =
 673                 objd_private(event_notifier_group_obj);
 674         struct lttng_event_notifier_enabler *event_notifier_enabler;
 675         int event_notifier_objd, ret;
 676
 677         event_notifier_param->event.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 678         event_notifier_objd = objd_alloc(NULL, &lttng_event_notifier_enabler_ops, owner,
 679                 "event_notifier enabler");
 680         if (event_notifier_objd < 0) {
 681                 ret = event_notifier_objd;
 682                 goto objd_error;
 683         }
 684
 685         event_notifier_enabler = lttng_event_notifier_enabler_create(
 686                 event_notifier_group, type, event_notifier_param);
 687         if (!event_notifier_enabler) {
 688                 ret = -ENOMEM;
 689                 goto event_notifier_error;
 690         }
 691
 692         objd_set_private(event_notifier_objd, event_notifier_enabler);
 693         /* The event_notifier holds a reference on the event_notifier group. */
 694         objd_ref(event_notifier_enabler->group->objd);
 695
 696         return event_notifier_objd;
 697
 698 event_notifier_error:
 699         {
 700                 int err;
 701
 702                 err = lttng_ust_objd_unref(event_notifier_objd, 1);
 703                 assert(!err);
 704         }
 705 objd_error:
 706         return ret;
 707 }
 708
 709 static
 710 long lttng_event_notifier_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
 711                 union ust_args *uargs, void *owner)
 712 {
 713         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 714         switch (cmd) {
 715         case LTTNG_UST_FILTER:
 716                 return lttng_event_notifier_enabler_attach_filter_bytecode(
 717                         event_notifier_enabler,
 718                         (struct lttng_ust_bytecode_node *) arg);
 719         case LTTNG_UST_EXCLUSION:
 720                 return lttng_event_notifier_enabler_attach_exclusion(event_notifier_enabler,
 721                         (struct lttng_ust_excluder_node *) arg);
 722         case LTTNG_UST_CAPTURE:
 723                 return lttng_event_notifier_enabler_attach_capture_bytecode(
 724                         event_notifier_enabler,
 725                         (struct lttng_ust_bytecode_node *) arg);
 726         case LTTNG_UST_ENABLE:
 727                 return lttng_event_notifier_enabler_enable(event_notifier_enabler);
 728         case LTTNG_UST_DISABLE:
 729                 return lttng_event_notifier_enabler_disable(event_notifier_enabler);
 730         default:
 731                 return -EINVAL;
 732         }
 733 }
 734
 735 /**
 736  *      lttng_event_notifier_group_error_counter_cmd - lttng event_notifier group error counter object command
 737  *
 738  *      @obj: the object
 739  *      @cmd: the command
 740  *      @arg: command arg
 741  *      @uargs: UST arguments (internal)
 742  *      @owner: objd owner
 743  *
 744  *      This descriptor implements lttng commands:
 745  *      LTTNG_UST_COUNTER_GLOBAL
 746  *        Return negative error code on error, 0 on success.
 747  *      LTTNG_UST_COUNTER_CPU
 748  *        Return negative error code on error, 0 on success.
 749  */
 750 static
 751 long lttng_event_notifier_group_error_counter_cmd(int objd, unsigned int cmd, unsigned long arg,
 752         union ust_args *uargs, void *owner)
 753 {
 754         struct lttng_counter *counter = objd_private(objd);
 755
 756         switch (cmd) {
 757         case LTTNG_UST_COUNTER_GLOBAL:
 758                 return -EINVAL;         /* Unimplemented. */
 759         case LTTNG_UST_COUNTER_CPU:
 760         {
 761                 struct lttng_ust_counter_cpu *counter_cpu =
 762                         (struct lttng_ust_counter_cpu *)arg;
 763                 return lttng_counter_set_cpu_shm(counter->counter,
 764                         counter_cpu->cpu_nr, uargs->counter_shm.shm_fd);
 765         }
 766         default:
 767                 return -EINVAL;
 768         }
 769 }
 770
 771 int lttng_release_event_notifier_group_error_counter(int objd)
 772 {
 773         struct lttng_counter *counter = objd_private(objd);
 774
 775         if (counter) {
 776                 return lttng_ust_objd_unref(counter->event_notifier_group->objd, 0);
 777         } else {
 778                 return -EINVAL;
 779         }
 780 }
 781
 782 static const struct lttng_ust_objd_ops lttng_event_notifier_group_error_counter_ops = {
 783         .release = lttng_release_event_notifier_group_error_counter,
 784         .cmd = lttng_event_notifier_group_error_counter_cmd,
 785 };
 786
 787 static
 788 int lttng_ust_event_notifier_group_create_error_counter(int event_notifier_group_objd, void *owner,
 789                 struct lttng_ust_counter_conf *error_counter_conf)
 790 {
 791         const char *counter_transport_name;
 792         struct lttng_event_notifier_group *event_notifier_group =
 793                 objd_private(event_notifier_group_objd);
 794         struct lttng_counter *counter;
 795         int counter_objd, ret;
 796         struct lttng_counter_dimension dimensions[1];
 797         size_t counter_len;
 798
 799         if (event_notifier_group->error_counter)
 800                 return -EBUSY;
 801
 802         if (error_counter_conf->arithmetic != LTTNG_UST_COUNTER_ARITHMETIC_MODULAR)
 803                 return -EINVAL;
 804
 805         if (error_counter_conf->number_dimensions != 1)
 806                 return -EINVAL;
 807
 808         switch (error_counter_conf->bitness) {
 809         case LTTNG_UST_COUNTER_BITNESS_64:
 810                 counter_transport_name = "counter-per-cpu-64-modular";
 811                 break;
 812         case LTTNG_UST_COUNTER_BITNESS_32:
 813                 counter_transport_name = "counter-per-cpu-32-modular";
 814                 break;
 815         default:
 816                 return -EINVAL;
 817         }
 818
 819         counter_objd = objd_alloc(NULL, &lttng_event_notifier_group_error_counter_ops, owner,
 820                 "event_notifier group error counter");
 821         if (counter_objd < 0) {
 822                 ret = counter_objd;
 823                 goto objd_error;
 824         }
 825
 826         counter_len = error_counter_conf->dimensions[0].size;
 827         dimensions[0].size = counter_len;
 828         dimensions[0].underflow_index = 0;
 829         dimensions[0].overflow_index = 0;
 830         dimensions[0].has_underflow = 0;
 831         dimensions[0].has_overflow = 0;
 832
 833         counter = lttng_ust_counter_create(counter_transport_name, 1, dimensions);
 834         if (!counter) {
 835                 ret = -EINVAL;
 836                 goto create_error;
 837         }
 838
 839         event_notifier_group->error_counter_len = counter_len;
 840         /*
 841          * store-release to publish error counter matches load-acquire
 842          * in record_error. Ensures the counter is created and the
 843          * error_counter_len is set before they are used.
 844          * Currently a full memory barrier is used, which could be
 845          * turned into acquire-release barriers.
 846          */
 847         cmm_smp_mb();
 848         CMM_STORE_SHARED(event_notifier_group->error_counter, counter);
 849
 850         counter->objd = counter_objd;
 851         counter->event_notifier_group = event_notifier_group;   /* owner */
 852
 853         objd_set_private(counter_objd, counter);
 854         /* The error counter holds a reference on the event_notifier group. */
 855         objd_ref(event_notifier_group->objd);
 856
 857         return counter_objd;
 858
 859 create_error:
 860         {
 861                 int err;
 862
 863                 err = lttng_ust_objd_unref(counter_objd, 1);
 864                 assert(!err);
 865         }
 866 objd_error:
 867         return ret;
 868 }
 869
 870 static
 871 long lttng_event_notifier_group_cmd(int objd, unsigned int cmd, unsigned long arg,
 872                 union ust_args *uargs, void *owner)
 873 {
 874         switch (cmd) {
 875         case LTTNG_UST_EVENT_NOTIFIER_CREATE:
 876         {
 877                 struct lttng_ust_event_notifier *event_notifier_param =
 878                         (struct lttng_ust_event_notifier *) arg;
 879                 if (strutils_is_star_glob_pattern(event_notifier_param->event.name)) {
 880                         /*
 881                          * If the event name is a star globbing pattern,
 882                          * we create the special star globbing enabler.
 883                          */
 884                         return lttng_ust_event_notifier_enabler_create(objd,
 885                                         owner, event_notifier_param,
 886                                         LTTNG_ENABLER_FORMAT_STAR_GLOB);
 887                 } else {
 888                         return lttng_ust_event_notifier_enabler_create(objd,
 889                                         owner, event_notifier_param,
 890                                         LTTNG_ENABLER_FORMAT_EVENT);
 891                 }
 892         }
 893         case LTTNG_UST_COUNTER:
 894         {
 895                 struct lttng_ust_counter_conf *counter_conf =
 896                         (struct lttng_ust_counter_conf *) uargs->counter.counter_data;
 897                 return lttng_ust_event_notifier_group_create_error_counter(
 898                                 objd, owner, counter_conf);
 899         }
 900         default:
 901                 return -EINVAL;
 902         }
 903 }
 904
 905 static
 906 int lttng_event_notifier_enabler_release(int objd)
 907 {
 908         struct lttng_event_notifier_enabler *event_notifier_enabler = objd_private(objd);
 909
 910         if (event_notifier_enabler)
 911                 return lttng_ust_objd_unref(event_notifier_enabler->group->objd, 0);
 912         return 0;
 913 }
 914
 915 static const struct lttng_ust_objd_ops lttng_event_notifier_enabler_ops = {
 916         .release = lttng_event_notifier_enabler_release,
 917         .cmd = lttng_event_notifier_enabler_cmd,
 918 };
 919
 920 static
 921 int lttng_release_event_notifier_group(int objd)
 922 {
 923         struct lttng_event_notifier_group *event_notifier_group = objd_private(objd);
 924
 925         if (event_notifier_group) {
 926                 lttng_event_notifier_group_destroy(event_notifier_group);
 927                 return 0;
 928         } else {
 929                 return -EINVAL;
 930         }
 931 }
 932
 933 static const struct lttng_ust_objd_ops lttng_event_notifier_group_ops = {
 934         .release = lttng_release_event_notifier_group,
 935         .cmd = lttng_event_notifier_group_cmd,
 936 };
 937
 938 static
 939 long lttng_tracepoint_list_cmd(int objd, unsigned int cmd, unsigned long arg,
 940         union ust_args *uargs, void *owner)
 941 {
 942         struct lttng_ust_tracepoint_list *list = objd_private(objd);
 943         struct lttng_ust_tracepoint_iter *tp =
 944                 (struct lttng_ust_tracepoint_iter *) arg;
 945         struct lttng_ust_tracepoint_iter *iter;
 946
 947         switch (cmd) {
 948         case LTTNG_UST_TRACEPOINT_LIST_GET:
 949         {
 950                 iter = lttng_ust_tracepoint_list_get_iter_next(list);
 951                 if (!iter)
 952                         return -LTTNG_UST_ERR_NOENT;
 953                 memcpy(tp, iter, sizeof(*tp));
 954                 return 0;
 955         }
 956         default:
 957                 return -EINVAL;
 958         }
 959 }
 960
 961 static
 962 int lttng_abi_tracepoint_list(void *owner)
 963 {
 964         int list_objd, ret;
 965         struct lttng_ust_tracepoint_list *list;
 966
 967         list_objd = objd_alloc(NULL, &lttng_tracepoint_list_ops, owner, "tp_list");
 968         if (list_objd < 0) {
 969                 ret = list_objd;
 970                 goto objd_error;
 971         }
 972         list = zmalloc(sizeof(*list));
 973         if (!list) {
 974                 ret = -ENOMEM;
 975                 goto alloc_error;
 976         }
 977         objd_set_private(list_objd, list);
 978
 979         /* populate list by walking on all registered probes. */
 980         ret = lttng_probes_get_event_list(list);
 981         if (ret) {
 982                 goto list_error;
 983         }
 984         return list_objd;
 985
 986 list_error:
 987         free(list);
 988 alloc_error:
 989         {
 990                 int err;
 991
 992                 err = lttng_ust_objd_unref(list_objd, 1);
 993                 assert(!err);
 994         }
 995 objd_error:
 996         return ret;
 997 }
 998
 999 static
1000 int lttng_release_tracepoint_list(int objd)
1001 {
1002         struct lttng_ust_tracepoint_list *list = objd_private(objd);
1003
1004         if (list) {
1005                 lttng_probes_prune_event_list(list);
1006                 free(list);
1007                 return 0;
1008         } else {
1009                 return -EINVAL;
1010         }
1011 }
1012
1013 static const struct lttng_ust_objd_ops lttng_tracepoint_list_ops = {
1014         .release = lttng_release_tracepoint_list,
1015         .cmd = lttng_tracepoint_list_cmd,
1016 };
1017
1018 static
1019 long lttng_tracepoint_field_list_cmd(int objd, unsigned int cmd,
1020         unsigned long arg, union ust_args *uargs, void *owner)
1021 {
1022         struct lttng_ust_field_list *list = objd_private(objd);
1023         struct lttng_ust_field_iter *tp = &uargs->field_list.entry;
1024         struct lttng_ust_field_iter *iter;
1025
1026         switch (cmd) {
1027         case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET:
1028         {
1029                 iter = lttng_ust_field_list_get_iter_next(list);
1030                 if (!iter)
1031                         return -LTTNG_UST_ERR_NOENT;
1032                 memcpy(tp, iter, sizeof(*tp));
1033                 return 0;
1034         }
1035         default:
1036                 return -EINVAL;
1037         }
1038 }
1039
1040 static
1041 int lttng_abi_tracepoint_field_list(void *owner)
1042 {
1043         int list_objd, ret;
1044         struct lttng_ust_field_list *list;
1045
1046         list_objd = objd_alloc(NULL, &lttng_tracepoint_field_list_ops, owner,
1047                         "tp_field_list");
1048         if (list_objd < 0) {
1049                 ret = list_objd;
1050                 goto objd_error;
1051         }
1052         list = zmalloc(sizeof(*list));
1053         if (!list) {
1054                 ret = -ENOMEM;
1055                 goto alloc_error;
1056         }
1057         objd_set_private(list_objd, list);
1058
1059         /* populate list by walking on all registered probes. */
1060         ret = lttng_probes_get_field_list(list);
1061         if (ret) {
1062                 goto list_error;
1063         }
1064         return list_objd;
1065
1066 list_error:
1067         free(list);
1068 alloc_error:
1069         {
1070                 int err;
1071
1072                 err = lttng_ust_objd_unref(list_objd, 1);
1073                 assert(!err);
1074         }
1075 objd_error:
1076         return ret;
1077 }
1078
1079 static
1080 int lttng_release_tracepoint_field_list(int objd)
1081 {
1082         struct lttng_ust_field_list *list = objd_private(objd);
1083
1084         if (list) {
1085                 lttng_probes_prune_field_list(list);
1086                 free(list);
1087                 return 0;
1088         } else {
1089                 return -EINVAL;
1090         }
1091 }
1092
1093 static const struct lttng_ust_objd_ops lttng_tracepoint_field_list_ops = {
1094         .release = lttng_release_tracepoint_field_list,
1095         .cmd = lttng_tracepoint_field_list_cmd,
1096 };
1097
1098 static
1099 int lttng_abi_map_stream(int channel_objd, struct lttng_ust_stream *info,
1100                 union ust_args *uargs, void *owner)
1101 {
1102         struct lttng_channel *channel = objd_private(channel_objd);
1103         int ret;
1104
1105         ret = channel_handle_add_stream(channel->handle,
1106                 uargs->stream.shm_fd, uargs->stream.wakeup_fd,
1107                 info->stream_nr, info->len);
1108         if (ret)
1109                 goto error_add_stream;
1110         /* Take ownership of shm_fd and wakeup_fd. */
1111         uargs->stream.shm_fd = -1;
1112         uargs->stream.wakeup_fd = -1;
1113
1114         return 0;
1115
1116 error_add_stream:
1117         return ret;
1118 }
1119
1120 static
1121 int lttng_abi_create_event_enabler(int channel_objd,
1122                            struct lttng_ust_event *event_param,
1123                            void *owner,
1124                            enum lttng_enabler_format_type format_type)
1125 {
1126         struct lttng_channel *channel = objd_private(channel_objd);
1127         struct lttng_event_enabler *enabler;
1128         int event_objd, ret;
1129
1130         event_param->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1131         event_objd = objd_alloc(NULL, &lttng_event_enabler_ops, owner,
1132                 "event enabler");
1133         if (event_objd < 0) {
1134                 ret = event_objd;
1135                 goto objd_error;
1136         }
1137         /*
1138          * We tolerate no failure path after event creation. It will stay
1139          * invariant for the rest of the session.
1140          */
1141         enabler = lttng_event_enabler_create(format_type, event_param, channel);
1142         if (!enabler) {
1143                 ret = -ENOMEM;
1144                 goto event_error;
1145         }
1146         objd_set_private(event_objd, enabler);
1147         /* The event holds a reference on the channel */
1148         objd_ref(channel_objd);
1149         return event_objd;
1150
1151 event_error:
1152         {
1153                 int err;
1154
1155                 err = lttng_ust_objd_unref(event_objd, 1);
1156                 assert(!err);
1157         }
1158 objd_error:
1159         return ret;
1160 }
1161
1162 /**
1163  *      lttng_channel_cmd - lttng control through object descriptors
1164  *
1165  *      @objd: the object descriptor
1166  *      @cmd: the command
1167  *      @arg: command arg
1168  *      @uargs: UST arguments (internal)
1169  *      @owner: objd owner
1170  *
1171  *      This object descriptor implements lttng commands:
1172  *      LTTNG_UST_STREAM
1173  *              Returns an event stream object descriptor or failure.
1174  *              (typically, one event stream records events from one CPU)
1175  *      LTTNG_UST_EVENT
1176  *              Returns an event object descriptor or failure.
1177  *      LTTNG_UST_CONTEXT
1178  *              Prepend a context field to each event in the channel
1179  *      LTTNG_UST_ENABLE
1180  *              Enable recording for events in this channel (weak enable)
1181  *      LTTNG_UST_DISABLE
1182  *              Disable recording for events in this channel (strong disable)
1183  *
1184  * Channel and event file descriptors also hold a reference on the session.
1185  */
1186 static
1187 long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg,
1188         union ust_args *uargs, void *owner)
1189 {
1190         struct lttng_channel *channel = objd_private(objd);
1191
1192         if (cmd != LTTNG_UST_STREAM) {
1193                 /*
1194                  * Check if channel received all streams.
1195                  */
1196                 if (!lttng_is_channel_ready(channel))
1197                         return -EPERM;
1198         }
1199
1200         switch (cmd) {
1201         case LTTNG_UST_STREAM:
1202         {
1203                 struct lttng_ust_stream *stream;
1204
1205                 stream = (struct lttng_ust_stream *) arg;
1206                 /* stream used as output */
1207                 return lttng_abi_map_stream(objd, stream, uargs, owner);
1208         }
1209         case LTTNG_UST_EVENT:
1210         {
1211                 struct lttng_ust_event *event_param =
1212                         (struct lttng_ust_event *) arg;
1213
1214                 if (strutils_is_star_glob_pattern(event_param->name)) {
1215                         /*
1216                          * If the event name is a star globbing pattern,
1217                          * we create the special star globbing enabler.
1218                          */
1219                         return lttng_abi_create_event_enabler(objd, event_param,
1220                                         owner, LTTNG_ENABLER_FORMAT_STAR_GLOB);
1221                 } else {
1222                         return lttng_abi_create_event_enabler(objd, event_param,
1223                                         owner, LTTNG_ENABLER_FORMAT_EVENT);
1224                 }
1225         }
1226         case LTTNG_UST_CONTEXT:
1227                 return lttng_abi_add_context(objd,
1228                                 (struct lttng_ust_context *) arg, uargs,
1229                                 &channel->ctx, channel->session);
1230         case LTTNG_UST_ENABLE:
1231                 return lttng_channel_enable(channel);
1232         case LTTNG_UST_DISABLE:
1233                 return lttng_channel_disable(channel);
1234         case LTTNG_UST_FLUSH_BUFFER:
1235                 return channel->ops->flush_buffer(channel->chan, channel->handle);
1236         default:
1237                 return -EINVAL;
1238         }
1239 }
1240
1241 static
1242 int lttng_channel_release(int objd)
1243 {
1244         struct lttng_channel *channel = objd_private(objd);
1245
1246         if (channel)
1247                 return lttng_ust_objd_unref(channel->session->objd, 0);
1248         return 0;
1249 }
1250
1251 static const struct lttng_ust_objd_ops lttng_channel_ops = {
1252         .release = lttng_channel_release,
1253         .cmd = lttng_channel_cmd,
1254 };
1255
1256 /**
1257  *      lttng_enabler_cmd - lttng control through object descriptors
1258  *
1259  *      @objd: the object descriptor
1260  *      @cmd: the command
1261  *      @arg: command arg
1262  *      @uargs: UST arguments (internal)
1263  *      @owner: objd owner
1264  *
1265  *      This object descriptor implements lttng commands:
1266  *      LTTNG_UST_CONTEXT
1267  *              Prepend a context field to each record of events of this
1268  *              enabler.
1269  *      LTTNG_UST_ENABLE
1270  *              Enable recording for this enabler
1271  *      LTTNG_UST_DISABLE
1272  *              Disable recording for this enabler
1273  *      LTTNG_UST_FILTER
1274  *              Attach a filter to an enabler.
1275  *      LTTNG_UST_EXCLUSION
1276  *              Attach exclusions to an enabler.
1277  */
1278 static
1279 long lttng_event_enabler_cmd(int objd, unsigned int cmd, unsigned long arg,
1280         union ust_args *uargs, void *owner)
1281 {
1282         struct lttng_event_enabler *enabler = objd_private(objd);
1283
1284         switch (cmd) {
1285         case LTTNG_UST_CONTEXT:
1286                 return lttng_event_enabler_attach_context(enabler,
1287                                 (struct lttng_ust_context *) arg);
1288         case LTTNG_UST_ENABLE:
1289                 return lttng_event_enabler_enable(enabler);
1290         case LTTNG_UST_DISABLE:
1291                 return lttng_event_enabler_disable(enabler);
1292         case LTTNG_UST_FILTER:
1293         {
1294                 int ret;
1295
1296                 ret = lttng_event_enabler_attach_filter_bytecode(enabler,
1297                                 (struct lttng_ust_bytecode_node *) arg);
1298                 if (ret)
1299                         return ret;
1300                 return 0;
1301         }
1302         case LTTNG_UST_EXCLUSION:
1303         {
1304                 return lttng_event_enabler_attach_exclusion(enabler,
1305                                 (struct lttng_ust_excluder_node *) arg);
1306         }
1307         default:
1308                 return -EINVAL;
1309         }
1310 }
1311
1312 static
1313 int lttng_event_enabler_release(int objd)
1314 {
1315         struct lttng_event_enabler *event_enabler = objd_private(objd);
1316
1317         if (event_enabler)
1318                 return lttng_ust_objd_unref(event_enabler->chan->objd, 0);
1319
1320         return 0;
1321 }
1322
1323 static const struct lttng_ust_objd_ops lttng_event_enabler_ops = {
1324         .release = lttng_event_enabler_release,
1325         .cmd = lttng_event_enabler_cmd,
1326 };
1327
1328 void lttng_ust_abi_exit(void)
1329 {
1330         lttng_ust_abi_close_in_progress = 1;
1331         ust_lock_nocheck();
1332         objd_table_destroy();
1333         ust_unlock();
1334         lttng_ust_abi_close_in_progress = 0;
1335 }