lttng-abi.c

   1 /*
   2  * lttng-abi.c
   3  *
   4  * LTTng 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 a file descriptor or failure.
  25  *   - channel creation, returns a file descriptor or failure.
  26  *     - Operates on a session file descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns a file descriptor or failure.
  29  *     - Operates on a channel file descriptor.
  30  *   - stream notifier get, returns a file descriptor or failure.
  31  *     - Operates on a channel file descriptor.
  32  *   - event creation, returns a file descriptor or failure.
  33  *     - Operates on a channel file descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/anon_inodes.h>
  43 #include <linux/file.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/slab.h>
  46 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  47 #include "wrapper/ringbuffer/vfs.h"
  48 #include "wrapper/ringbuffer/backend.h"
  49 #include "wrapper/ringbuffer/frontend.h"
  50 #include "wrapper/poll.h"
  51 #include "lttng-abi.h"
  52 #include "lttng-abi-old.h"
  53 #include "lttng-events.h"
  54 #include "lttng-tracer.h"
  55
  56 /*
  57  * This is LTTng's own personal way to create a system call as an external
  58  * module. We use ioctl() on /proc/lttng.
  59  */
  60
  61 static struct proc_dir_entry *lttng_proc_dentry;
  62 static const struct file_operations lttng_fops;
  63 static const struct file_operations lttng_session_fops;
  64 static const struct file_operations lttng_channel_fops;
  65 static const struct file_operations lttng_metadata_fops;
  66 static const struct file_operations lttng_event_fops;
  67
  68 /*
  69  * Teardown management: opened file descriptors keep a refcount on the module,
  70  * so it can only exit when all file descriptors are closed.
  71  */
  72
  73 static
  74 int lttng_abi_create_session(void)
  75 {
  76         struct lttng_session *session;
  77         struct file *session_file;
  78         int session_fd, ret;
  79
  80         session = lttng_session_create();
  81         if (!session)
  82                 return -ENOMEM;
  83         session_fd = get_unused_fd();
  84         if (session_fd < 0) {
  85                 ret = session_fd;
  86                 goto fd_error;
  87         }
  88         session_file = anon_inode_getfile("[lttng_session]",
  89                                           &lttng_session_fops,
  90                                           session, O_RDWR);
  91         if (IS_ERR(session_file)) {
  92                 ret = PTR_ERR(session_file);
  93                 goto file_error;
  94         }
  95         session->file = session_file;
  96         fd_install(session_fd, session_file);
  97         return session_fd;
  98
  99 file_error:
 100         put_unused_fd(session_fd);
 101 fd_error:
 102         lttng_session_destroy(session);
 103         return ret;
 104 }
 105
 106 static
 107 int lttng_abi_tracepoint_list(void)
 108 {
 109         struct file *tracepoint_list_file;
 110         int file_fd, ret;
 111
 112         file_fd = get_unused_fd();
 113         if (file_fd < 0) {
 114                 ret = file_fd;
 115                 goto fd_error;
 116         }
 117
 118         tracepoint_list_file = anon_inode_getfile("[lttng_session]",
 119                                           &lttng_tracepoint_list_fops,
 120                                           NULL, O_RDWR);
 121         if (IS_ERR(tracepoint_list_file)) {
 122                 ret = PTR_ERR(tracepoint_list_file);
 123                 goto file_error;
 124         }
 125         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 126         if (ret < 0)
 127                 goto open_error;
 128         fd_install(file_fd, tracepoint_list_file);
 129         if (file_fd < 0) {
 130                 ret = file_fd;
 131                 goto fd_error;
 132         }
 133         return file_fd;
 134
 135 open_error:
 136         fput(tracepoint_list_file);
 137 file_error:
 138         put_unused_fd(file_fd);
 139 fd_error:
 140         return ret;
 141 }
 142
 143 static
 144 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 145 {
 146         v->major = LTTNG_MODULES_MAJOR_VERSION;
 147         v->minor = LTTNG_MODULES_MINOR_VERSION;
 148         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 149 }
 150
 151 static
 152 long lttng_abi_add_context(struct file *file,
 153         struct lttng_kernel_context *context_param,
 154         struct lttng_ctx **ctx, struct lttng_session *session)
 155 {
 156
 157         if (session->been_active)
 158                 return -EPERM;
 159
 160         switch (context_param->ctx) {
 161         case LTTNG_KERNEL_CONTEXT_PID:
 162                 return lttng_add_pid_to_ctx(ctx);
 163         case LTTNG_KERNEL_CONTEXT_PRIO:
 164                 return lttng_add_prio_to_ctx(ctx);
 165         case LTTNG_KERNEL_CONTEXT_NICE:
 166                 return lttng_add_nice_to_ctx(ctx);
 167         case LTTNG_KERNEL_CONTEXT_VPID:
 168                 return lttng_add_vpid_to_ctx(ctx);
 169         case LTTNG_KERNEL_CONTEXT_TID:
 170                 return lttng_add_tid_to_ctx(ctx);
 171         case LTTNG_KERNEL_CONTEXT_VTID:
 172                 return lttng_add_vtid_to_ctx(ctx);
 173         case LTTNG_KERNEL_CONTEXT_PPID:
 174                 return lttng_add_ppid_to_ctx(ctx);
 175         case LTTNG_KERNEL_CONTEXT_VPPID:
 176                 return lttng_add_vppid_to_ctx(ctx);
 177         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 178                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 179                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 180                                 context_param->u.perf_counter.config,
 181                                 context_param->u.perf_counter.name,
 182                                 ctx);
 183         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 184                 return lttng_add_procname_to_ctx(ctx);
 185         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 186                 return lttng_add_hostname_to_ctx(ctx);
 187         default:
 188                 return -EINVAL;
 189         }
 190 }
 191
 192 /**
 193  *      lttng_ioctl - lttng syscall through ioctl
 194  *
 195  *      @file: the file
 196  *      @cmd: the command
 197  *      @arg: command arg
 198  *
 199  *      This ioctl implements lttng commands:
 200  *      LTTNG_KERNEL_SESSION
 201  *              Returns a LTTng trace session file descriptor
 202  *      LTTNG_KERNEL_TRACER_VERSION
 203  *              Returns the LTTng kernel tracer version
 204  *      LTTNG_KERNEL_TRACEPOINT_LIST
 205  *              Returns a file descriptor listing available tracepoints
 206  *      LTTNG_KERNEL_WAIT_QUIESCENT
 207  *              Returns after all previously running probes have completed
 208  *
 209  * The returned session will be deleted when its file descriptor is closed.
 210  */
 211 static
 212 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 213 {
 214         switch (cmd) {
 215         case LTTNG_KERNEL_OLD_SESSION:
 216         case LTTNG_KERNEL_SESSION:
 217                 return lttng_abi_create_session();
 218         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 219         {
 220                 struct lttng_kernel_tracer_version v;
 221                 struct lttng_kernel_old_tracer_version oldv;
 222                 struct lttng_kernel_old_tracer_version *uversion =
 223                         (struct lttng_kernel_old_tracer_version __user *) arg;
 224
 225                 lttng_abi_tracer_version(&v);
 226                 oldv.major = v.major;
 227                 oldv.minor = v.minor;
 228                 oldv.patchlevel = v.patchlevel;
 229
 230                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 231                         return -EFAULT;
 232                 return 0;
 233         }
 234         case LTTNG_KERNEL_TRACER_VERSION:
 235         {
 236                 struct lttng_kernel_tracer_version version;
 237                 struct lttng_kernel_tracer_version *uversion =
 238                         (struct lttng_kernel_tracer_version __user *) arg;
 239
 240                 lttng_abi_tracer_version(&version);
 241
 242                 if (copy_to_user(uversion, &version, sizeof(version)))
 243                         return -EFAULT;
 244                 return 0;
 245         }
 246         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 247         case LTTNG_KERNEL_TRACEPOINT_LIST:
 248                 return lttng_abi_tracepoint_list();
 249         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 250         case LTTNG_KERNEL_WAIT_QUIESCENT:
 251                 synchronize_trace();
 252                 return 0;
 253         case LTTNG_KERNEL_OLD_CALIBRATE:
 254         {
 255                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 256                         (struct lttng_kernel_old_calibrate __user *) arg;
 257                 struct lttng_kernel_old_calibrate old_calibrate;
 258                 struct lttng_kernel_calibrate calibrate;
 259                 int ret;
 260
 261                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 262                         return -EFAULT;
 263                 calibrate.type = old_calibrate.type;
 264                 ret = lttng_calibrate(&calibrate);
 265                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 266                         return -EFAULT;
 267                 return ret;
 268         }
 269         case LTTNG_KERNEL_CALIBRATE:
 270         {
 271                 struct lttng_kernel_calibrate __user *ucalibrate =
 272                         (struct lttng_kernel_calibrate __user *) arg;
 273                 struct lttng_kernel_calibrate calibrate;
 274                 int ret;
 275
 276                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 277                         return -EFAULT;
 278                 ret = lttng_calibrate(&calibrate);
 279                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 280                         return -EFAULT;
 281                 return ret;
 282         }
 283         default:
 284                 return -ENOIOCTLCMD;
 285         }
 286 }
 287
 288 static const struct file_operations lttng_fops = {
 289         .owner = THIS_MODULE,
 290         .unlocked_ioctl = lttng_ioctl,
 291 #ifdef CONFIG_COMPAT
 292         .compat_ioctl = lttng_ioctl,
 293 #endif
 294 };
 295
 296 static
 297 int lttng_abi_create_channel(struct file *session_file,
 298                              struct lttng_kernel_channel *chan_param,
 299                              enum channel_type channel_type)
 300 {
 301         struct lttng_session *session = session_file->private_data;
 302         const struct file_operations *fops = NULL;
 303         const char *transport_name;
 304         struct lttng_channel *chan;
 305         struct file *chan_file;
 306         int chan_fd;
 307         int ret = 0;
 308
 309         chan_fd = get_unused_fd();
 310         if (chan_fd < 0) {
 311                 ret = chan_fd;
 312                 goto fd_error;
 313         }
 314         switch (channel_type) {
 315         case PER_CPU_CHANNEL:
 316                 fops = &lttng_channel_fops;
 317                 break;
 318         case METADATA_CHANNEL:
 319                 fops = &lttng_metadata_fops;
 320                 break;
 321         }
 322
 323         chan_file = anon_inode_getfile("[lttng_channel]",
 324                                        fops,
 325                                        NULL, O_RDWR);
 326         if (IS_ERR(chan_file)) {
 327                 ret = PTR_ERR(chan_file);
 328                 goto file_error;
 329         }
 330         switch (channel_type) {
 331         case PER_CPU_CHANNEL:
 332                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 333                         transport_name = chan_param->overwrite ?
 334                                 "relay-overwrite" : "relay-discard";
 335                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 336                         transport_name = chan_param->overwrite ?
 337                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 338                 } else {
 339                         return -EINVAL;
 340                 }
 341                 break;
 342         case METADATA_CHANNEL:
 343                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 344                         transport_name = "relay-metadata";
 345                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 346                         transport_name = "relay-metadata-mmap";
 347                 else
 348                         return -EINVAL;
 349                 break;
 350         default:
 351                 transport_name = "<unknown>";
 352                 break;
 353         }
 354         /*
 355          * We tolerate no failure path after channel creation. It will stay
 356          * invariant for the rest of the session.
 357          */
 358         chan = lttng_channel_create(session, transport_name, NULL,
 359                                   chan_param->subbuf_size,
 360                                   chan_param->num_subbuf,
 361                                   chan_param->switch_timer_interval,
 362                                   chan_param->read_timer_interval,
 363                                   channel_type);
 364         if (!chan) {
 365                 ret = -EINVAL;
 366                 goto chan_error;
 367         }
 368         chan->file = chan_file;
 369         chan_file->private_data = chan;
 370         fd_install(chan_fd, chan_file);
 371         atomic_long_inc(&session_file->f_count);
 372
 373         return chan_fd;
 374
 375 chan_error:
 376         fput(chan_file);
 377 file_error:
 378         put_unused_fd(chan_fd);
 379 fd_error:
 380         return ret;
 381 }
 382
 383 /**
 384  *      lttng_session_ioctl - lttng session fd ioctl
 385  *
 386  *      @file: the file
 387  *      @cmd: the command
 388  *      @arg: command arg
 389  *
 390  *      This ioctl implements lttng commands:
 391  *      LTTNG_KERNEL_CHANNEL
 392  *              Returns a LTTng channel file descriptor
 393  *      LTTNG_KERNEL_ENABLE
 394  *              Enables tracing for a session (weak enable)
 395  *      LTTNG_KERNEL_DISABLE
 396  *              Disables tracing for a session (strong disable)
 397  *      LTTNG_KERNEL_METADATA
 398  *              Returns a LTTng metadata file descriptor
 399  *
 400  * The returned channel will be deleted when its file descriptor is closed.
 401  */
 402 static
 403 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 404 {
 405         struct lttng_session *session = file->private_data;
 406
 407         switch (cmd) {
 408         case LTTNG_KERNEL_OLD_CHANNEL:
 409         {
 410                 struct lttng_kernel_channel chan_param;
 411                 struct lttng_kernel_old_channel old_chan_param;
 412
 413                 if (copy_from_user(&old_chan_param,
 414                                 (struct lttng_kernel_old_channel __user *) arg,
 415                                 sizeof(struct lttng_kernel_old_channel)))
 416                         return -EFAULT;
 417                 chan_param.overwrite = old_chan_param.overwrite;
 418                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 419                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 420                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 421                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 422                 chan_param.output = old_chan_param.output;
 423
 424                 return lttng_abi_create_channel(file, &chan_param,
 425                                 PER_CPU_CHANNEL);
 426         }
 427         case LTTNG_KERNEL_CHANNEL:
 428         {
 429                 struct lttng_kernel_channel chan_param;
 430
 431                 if (copy_from_user(&chan_param,
 432                                 (struct lttng_kernel_channel __user *) arg,
 433                                 sizeof(struct lttng_kernel_channel)))
 434                         return -EFAULT;
 435                 return lttng_abi_create_channel(file, &chan_param,
 436                                 PER_CPU_CHANNEL);
 437         }
 438         case LTTNG_KERNEL_OLD_SESSION_START:
 439         case LTTNG_KERNEL_OLD_ENABLE:
 440         case LTTNG_KERNEL_SESSION_START:
 441         case LTTNG_KERNEL_ENABLE:
 442                 return lttng_session_enable(session);
 443         case LTTNG_KERNEL_OLD_SESSION_STOP:
 444         case LTTNG_KERNEL_OLD_DISABLE:
 445         case LTTNG_KERNEL_SESSION_STOP:
 446         case LTTNG_KERNEL_DISABLE:
 447                 return lttng_session_disable(session);
 448         case LTTNG_KERNEL_OLD_METADATA:
 449         {
 450                 struct lttng_kernel_channel chan_param;
 451                 struct lttng_kernel_old_channel old_chan_param;
 452
 453                 if (copy_from_user(&old_chan_param,
 454                                 (struct lttng_kernel_old_channel __user *) arg,
 455                                 sizeof(struct lttng_kernel_old_channel)))
 456                         return -EFAULT;
 457                 chan_param.overwrite = old_chan_param.overwrite;
 458                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 459                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 460                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 461                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 462                 chan_param.output = old_chan_param.output;
 463
 464                 return lttng_abi_create_channel(file, &chan_param,
 465                                 METADATA_CHANNEL);
 466         }
 467         case LTTNG_KERNEL_METADATA:
 468         {
 469                 struct lttng_kernel_channel chan_param;
 470
 471                 if (copy_from_user(&chan_param,
 472                                         (struct lttng_kernel_channel __user *) arg,
 473                                         sizeof(struct lttng_kernel_channel)))
 474                         return -EFAULT;
 475                 return lttng_abi_create_channel(file, &chan_param,
 476                                 METADATA_CHANNEL);
 477         }
 478         default:
 479                 return -ENOIOCTLCMD;
 480         }
 481 }
 482
 483 /*
 484  * Called when the last file reference is dropped.
 485  *
 486  * Big fat note: channels and events are invariant for the whole session after
 487  * their creation. So this session destruction also destroys all channel and
 488  * event structures specific to this session (they are not destroyed when their
 489  * individual file is released).
 490  */
 491 static
 492 int lttng_session_release(struct inode *inode, struct file *file)
 493 {
 494         struct lttng_session *session = file->private_data;
 495
 496         if (session)
 497                 lttng_session_destroy(session);
 498         return 0;
 499 }
 500
 501 static const struct file_operations lttng_session_fops = {
 502         .owner = THIS_MODULE,
 503         .release = lttng_session_release,
 504         .unlocked_ioctl = lttng_session_ioctl,
 505 #ifdef CONFIG_COMPAT
 506         .compat_ioctl = lttng_session_ioctl,
 507 #endif
 508 };
 509
 510 /**
 511  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 512  *      @filp: the file
 513  *      @wait: poll table
 514  *
 515  *      Handles the poll operations for the metadata channels.
 516  */
 517 static
 518 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 519                 poll_table *wait)
 520 {
 521         struct lttng_metadata_stream *stream = filp->private_data;
 522         struct lib_ring_buffer *buf = stream->priv;
 523         int finalized;
 524         unsigned int mask = 0;
 525
 526         if (filp->f_mode & FMODE_READ) {
 527                 poll_wait_set_exclusive(wait);
 528                 poll_wait(filp, &stream->read_wait, wait);
 529
 530                 finalized = stream->finalized;
 531
 532                 /*
 533                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 534                  * ordering finalized load before offsets loads.
 535                  */
 536                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 537
 538                 if (finalized)
 539                         mask |= POLLHUP;
 540
 541                 if (stream->metadata_cache->metadata_written >
 542                                 stream->metadata_out)
 543                         mask |= POLLIN;
 544         }
 545
 546         return mask;
 547 }
 548
 549 static
 550 int lttng_metadata_ring_buffer_ioctl_get_next_subbuf(struct file *filp,
 551                 unsigned int cmd, unsigned long arg)
 552 {
 553         struct lttng_metadata_stream *stream = filp->private_data;
 554         struct lib_ring_buffer *buf = stream->priv;
 555         struct channel *chan = buf->backend.chan;
 556         struct lttng_channel *lttng_chan = channel_get_private(chan);
 557         int ret;
 558
 559         ret = lttng_metadata_output_channel(lttng_chan, stream);
 560         if (ret > 0) {
 561                 lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 562                 ret = 0;
 563         }
 564         return ret;
 565 }
 566
 567 static
 568 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 569                 unsigned int cmd, unsigned long arg)
 570 {
 571         struct lttng_metadata_stream *stream = filp->private_data;
 572
 573         stream->metadata_out = stream->metadata_in;
 574 }
 575
 576 static
 577 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 578                 unsigned int cmd, unsigned long arg)
 579 {
 580         int ret;
 581         struct lttng_metadata_stream *stream = filp->private_data;
 582         struct lib_ring_buffer *buf = stream->priv;
 583
 584         switch (cmd) {
 585         case RING_BUFFER_GET_NEXT_SUBBUF:
 586         {
 587                 ret = lttng_metadata_ring_buffer_ioctl_get_next_subbuf(filp,
 588                                 cmd, arg);
 589                 if (ret < 0)
 590                         goto err;
 591                 break;
 592         }
 593         case RING_BUFFER_GET_SUBBUF:
 594         {
 595                 /*
 596                  * Random access is not allowed for metadata channel.
 597                  */
 598                 return -ENOSYS;
 599         }
 600         default:
 601                 break;
 602         }
 603         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 604
 605         /* Performing lib ring buffer ioctl after our own. */
 606         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 607         if (ret < 0)
 608                 goto err;
 609
 610         switch (cmd) {
 611         case RING_BUFFER_PUT_NEXT_SUBBUF:
 612         {
 613                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 614                                 cmd, arg);
 615                 break;
 616         }
 617         default:
 618                 break;
 619         }
 620 err:
 621         return ret;
 622 }
 623
 624 #ifdef CONFIG_COMPAT
 625 static
 626 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 627                 unsigned int cmd, unsigned long arg)
 628 {
 629         int ret;
 630         struct lttng_metadata_stream *stream = filp->private_data;
 631         struct lib_ring_buffer *buf = stream->priv;
 632
 633         switch (cmd) {
 634         case RING_BUFFER_GET_NEXT_SUBBUF:
 635         {
 636                 ret = lttng_metadata_ring_buffer_ioctl_get_next_subbuf(filp,
 637                                 cmd, arg);
 638                 if (ret < 0)
 639                         goto err;
 640                 break;
 641         }
 642         case RING_BUFFER_GET_SUBBUF:
 643         {
 644                 /*
 645                  * Random access is not allowed for metadata channel.
 646                  */
 647                 return -ENOSYS;
 648         }
 649         default:
 650                 break;
 651         }
 652         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 653
 654         /* Performing lib ring buffer ioctl after our own. */
 655         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 656         if (ret < 0)
 657                 goto err;
 658
 659         switch (cmd) {
 660         case RING_BUFFER_PUT_NEXT_SUBBUF:
 661         {
 662                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 663                                 cmd, arg);
 664                 break;
 665         }
 666         default:
 667                 break;
 668         }
 669 err:
 670         return ret;
 671 }
 672 #endif
 673
 674 static
 675 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 676 {
 677         struct lttng_metadata_stream *stream = inode->i_private;
 678         struct lib_ring_buffer *buf = stream->priv;
 679
 680         file->private_data = buf;
 681         return lib_ring_buffer_open(inode, file, buf);
 682 }
 683
 684 static
 685 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 686 {
 687         struct lttng_metadata_stream *stream = file->private_data;
 688         struct lib_ring_buffer *buf = stream->priv;
 689         struct channel *chan = buf->backend.chan;
 690         struct lttng_channel *lttng_chan = channel_get_private(chan);
 691
 692         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 693         fput(lttng_chan->file);
 694
 695         return lib_ring_buffer_release(inode, file, buf);
 696 }
 697
 698 static
 699 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 700                 struct pipe_inode_info *pipe, size_t len,
 701                 unsigned int flags)
 702 {
 703         struct lttng_metadata_stream *stream = in->private_data;
 704         struct lib_ring_buffer *buf = stream->priv;
 705
 706         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 707                         flags, buf);
 708 }
 709
 710 static
 711 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 712                 struct vm_area_struct *vma)
 713 {
 714         struct lttng_metadata_stream *stream = filp->private_data;
 715         struct lib_ring_buffer *buf = stream->priv;
 716
 717         return lib_ring_buffer_mmap(filp, vma, buf);
 718 }
 719
 720 static
 721 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 722         .owner = THIS_MODULE,
 723         .open = lttng_metadata_ring_buffer_open,
 724         .release = lttng_metadata_ring_buffer_release,
 725         .poll = lttng_metadata_ring_buffer_poll,
 726         .splice_read = lttng_metadata_ring_buffer_splice_read,
 727         .mmap = lttng_metadata_ring_buffer_mmap,
 728         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 729         .llseek = vfs_lib_ring_buffer_no_llseek,
 730 #ifdef CONFIG_COMPAT
 731         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 732 #endif
 733 };
 734
 735 static
 736 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 737                 const struct file_operations *fops)
 738 {
 739         int stream_fd, ret;
 740         struct file *stream_file;
 741
 742         stream_fd = get_unused_fd();
 743         if (stream_fd < 0) {
 744                 ret = stream_fd;
 745                 goto fd_error;
 746         }
 747         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 748                         stream_priv, O_RDWR);
 749         if (IS_ERR(stream_file)) {
 750                 ret = PTR_ERR(stream_file);
 751                 goto file_error;
 752         }
 753         /*
 754          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 755          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 756          * file descriptor, so we set FMODE_PREAD here.
 757          */
 758         stream_file->f_mode |= FMODE_PREAD;
 759         fd_install(stream_fd, stream_file);
 760         /*
 761          * The stream holds a reference to the channel within the generic ring
 762          * buffer library, so no need to hold a refcount on the channel and
 763          * session files here.
 764          */
 765         return stream_fd;
 766
 767 file_error:
 768         put_unused_fd(stream_fd);
 769 fd_error:
 770         return ret;
 771 }
 772
 773 static
 774 int lttng_abi_open_stream(struct file *channel_file)
 775 {
 776         struct lttng_channel *channel = channel_file->private_data;
 777         struct lib_ring_buffer *buf;
 778         int ret;
 779         void *stream_priv;
 780
 781         buf = channel->ops->buffer_read_open(channel->chan);
 782         if (!buf)
 783                 return -ENOENT;
 784
 785         stream_priv = buf;
 786         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 787                         &lib_ring_buffer_file_operations);
 788         if (ret < 0)
 789                 goto fd_error;
 790
 791         return ret;
 792
 793 fd_error:
 794         channel->ops->buffer_read_close(buf);
 795         return ret;
 796 }
 797
 798 static
 799 int lttng_abi_open_metadata_stream(struct file *channel_file)
 800 {
 801         struct lttng_channel *channel = channel_file->private_data;
 802         struct lttng_session *session = channel->session;
 803         struct lib_ring_buffer *buf;
 804         int ret;
 805         struct lttng_metadata_stream *metadata_stream;
 806         void *stream_priv;
 807
 808         buf = channel->ops->buffer_read_open(channel->chan);
 809         if (!buf)
 810                 return -ENOENT;
 811
 812         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 813                         GFP_KERNEL);
 814         if (!metadata_stream)
 815                 return -ENOMEM;
 816         metadata_stream->metadata_cache = session->metadata_cache;
 817         init_waitqueue_head(&metadata_stream->read_wait);
 818         metadata_stream->priv = buf;
 819         stream_priv = metadata_stream;
 820         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 821                         &lttng_metadata_ring_buffer_file_operations);
 822         if (ret < 0)
 823                 goto fd_error;
 824
 825         atomic_long_inc(&channel_file->f_count);
 826         kref_get(&session->metadata_cache->refcount);
 827         list_add(&metadata_stream->list,
 828                 &session->metadata_cache->metadata_stream);
 829         return ret;
 830
 831 fd_error:
 832         channel->ops->buffer_read_close(buf);
 833         return ret;
 834 }
 835
 836 static
 837 int lttng_abi_create_event(struct file *channel_file,
 838                            struct lttng_kernel_event *event_param)
 839 {
 840         struct lttng_channel *channel = channel_file->private_data;
 841         struct lttng_event *event;
 842         int event_fd, ret;
 843         struct file *event_file;
 844
 845         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 846         switch (event_param->instrumentation) {
 847         case LTTNG_KERNEL_KRETPROBE:
 848                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 849                 break;
 850         case LTTNG_KERNEL_KPROBE:
 851                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 852                 break;
 853         case LTTNG_KERNEL_FUNCTION:
 854                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 855                 break;
 856         default:
 857                 break;
 858         }
 859         switch (event_param->instrumentation) {
 860         default:
 861                 event_fd = get_unused_fd();
 862                 if (event_fd < 0) {
 863                         ret = event_fd;
 864                         goto fd_error;
 865                 }
 866                 event_file = anon_inode_getfile("[lttng_event]",
 867                                                 &lttng_event_fops,
 868                                                 NULL, O_RDWR);
 869                 if (IS_ERR(event_file)) {
 870                         ret = PTR_ERR(event_file);
 871                         goto file_error;
 872                 }
 873                 /*
 874                  * We tolerate no failure path after event creation. It
 875                  * will stay invariant for the rest of the session.
 876                  */
 877                 event = lttng_event_create(channel, event_param, NULL, NULL);
 878                 if (!event) {
 879                         ret = -EINVAL;
 880                         goto event_error;
 881                 }
 882                 event_file->private_data = event;
 883                 fd_install(event_fd, event_file);
 884                 /* The event holds a reference on the channel */
 885                 atomic_long_inc(&channel_file->f_count);
 886                 break;
 887         case LTTNG_KERNEL_SYSCALL:
 888                 /*
 889                  * Only all-syscall tracing supported for now.
 890                  */
 891                 if (event_param->name[0] != '\0')
 892                         return -EINVAL;
 893                 ret = lttng_syscalls_register(channel, NULL);
 894                 if (ret)
 895                         goto fd_error;
 896                 event_fd = 0;
 897                 break;
 898         }
 899         return event_fd;
 900
 901 event_error:
 902         fput(event_file);
 903 file_error:
 904         put_unused_fd(event_fd);
 905 fd_error:
 906         return ret;
 907 }
 908
 909 /**
 910  *      lttng_channel_ioctl - lttng syscall through ioctl
 911  *
 912  *      @file: the file
 913  *      @cmd: the command
 914  *      @arg: command arg
 915  *
 916  *      This ioctl implements lttng commands:
 917  *      LTTNG_KERNEL_STREAM
 918  *              Returns an event stream file descriptor or failure.
 919  *              (typically, one event stream records events from one CPU)
 920  *      LTTNG_KERNEL_EVENT
 921  *              Returns an event file descriptor or failure.
 922  *      LTTNG_KERNEL_CONTEXT
 923  *              Prepend a context field to each event in the channel
 924  *      LTTNG_KERNEL_ENABLE
 925  *              Enable recording for events in this channel (weak enable)
 926  *      LTTNG_KERNEL_DISABLE
 927  *              Disable recording for events in this channel (strong disable)
 928  *
 929  * Channel and event file descriptors also hold a reference on the session.
 930  */
 931 static
 932 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 933 {
 934         struct lttng_channel *channel = file->private_data;
 935
 936         switch (cmd) {
 937         case LTTNG_KERNEL_OLD_STREAM:
 938         case LTTNG_KERNEL_STREAM:
 939                 return lttng_abi_open_stream(file);
 940         case LTTNG_KERNEL_OLD_EVENT:
 941         {
 942                 struct lttng_kernel_event *uevent_param;
 943                 struct lttng_kernel_old_event *old_uevent_param;
 944                 int ret;
 945
 946                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
 947                                 GFP_KERNEL);
 948                 if (!uevent_param) {
 949                         ret = -ENOMEM;
 950                         goto old_event_end;
 951                 }
 952                 old_uevent_param = kmalloc(
 953                                 sizeof(struct lttng_kernel_old_event),
 954                                 GFP_KERNEL);
 955                 if (!old_uevent_param) {
 956                         ret = -ENOMEM;
 957                         goto old_event_error_free_param;
 958                 }
 959                 if (copy_from_user(old_uevent_param,
 960                                 (struct lttng_kernel_old_event __user *) arg,
 961                                 sizeof(struct lttng_kernel_old_event))) {
 962                         ret = -EFAULT;
 963                         goto old_event_error_free_old_param;
 964                 }
 965
 966                 memcpy(uevent_param->name, old_uevent_param->name,
 967                                 sizeof(uevent_param->name));
 968                 uevent_param->instrumentation =
 969                         old_uevent_param->instrumentation;
 970
 971                 switch (old_uevent_param->instrumentation) {
 972                 case LTTNG_KERNEL_KPROBE:
 973                         uevent_param->u.kprobe.addr =
 974                                 old_uevent_param->u.kprobe.addr;
 975                         uevent_param->u.kprobe.offset =
 976                                 old_uevent_param->u.kprobe.offset;
 977                         memcpy(uevent_param->u.kprobe.symbol_name,
 978                                 old_uevent_param->u.kprobe.symbol_name,
 979                                 sizeof(uevent_param->u.kprobe.symbol_name));
 980                         break;
 981                 case LTTNG_KERNEL_KRETPROBE:
 982                         uevent_param->u.kretprobe.addr =
 983                                 old_uevent_param->u.kretprobe.addr;
 984                         uevent_param->u.kretprobe.offset =
 985                                 old_uevent_param->u.kretprobe.offset;
 986                         memcpy(uevent_param->u.kretprobe.symbol_name,
 987                                 old_uevent_param->u.kretprobe.symbol_name,
 988                                 sizeof(uevent_param->u.kretprobe.symbol_name));
 989                         break;
 990                 case LTTNG_KERNEL_FUNCTION:
 991                         memcpy(uevent_param->u.ftrace.symbol_name,
 992                                         old_uevent_param->u.ftrace.symbol_name,
 993                                         sizeof(uevent_param->u.ftrace.symbol_name));
 994                         break;
 995                 default:
 996                         break;
 997                 }
 998                 ret = lttng_abi_create_event(file, uevent_param);
 999
1000 old_event_error_free_old_param:
1001                 kfree(old_uevent_param);
1002 old_event_error_free_param:
1003                 kfree(uevent_param);
1004 old_event_end:
1005                 return ret;
1006         }
1007         case LTTNG_KERNEL_EVENT:
1008         {
1009                 struct lttng_kernel_event uevent_param;
1010
1011                 if (copy_from_user(&uevent_param,
1012                                 (struct lttng_kernel_event __user *) arg,
1013                                 sizeof(uevent_param)))
1014                         return -EFAULT;
1015                 return lttng_abi_create_event(file, &uevent_param);
1016         }
1017         case LTTNG_KERNEL_OLD_CONTEXT:
1018         {
1019                 struct lttng_kernel_context *ucontext_param;
1020                 struct lttng_kernel_old_context *old_ucontext_param;
1021                 int ret;
1022
1023                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1024                                 GFP_KERNEL);
1025                 if (!ucontext_param) {
1026                         ret = -ENOMEM;
1027                         goto old_ctx_end;
1028                 }
1029                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1030                                 GFP_KERNEL);
1031                 if (!old_ucontext_param) {
1032                         ret = -ENOMEM;
1033                         goto old_ctx_error_free_param;
1034                 }
1035
1036                 if (copy_from_user(old_ucontext_param,
1037                                 (struct lttng_kernel_old_context __user *) arg,
1038                                 sizeof(struct lttng_kernel_old_context))) {
1039                         ret = -EFAULT;
1040                         goto old_ctx_error_free_old_param;
1041                 }
1042                 ucontext_param->ctx = old_ucontext_param->ctx;
1043                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1044                                 sizeof(ucontext_param->padding));
1045                 /* only type that uses the union */
1046                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1047                         ucontext_param->u.perf_counter.type =
1048                                 old_ucontext_param->u.perf_counter.type;
1049                         ucontext_param->u.perf_counter.config =
1050                                 old_ucontext_param->u.perf_counter.config;
1051                         memcpy(ucontext_param->u.perf_counter.name,
1052                                 old_ucontext_param->u.perf_counter.name,
1053                                 sizeof(ucontext_param->u.perf_counter.name));
1054                 }
1055
1056                 ret = lttng_abi_add_context(file,
1057                                 ucontext_param,
1058                                 &channel->ctx, channel->session);
1059
1060 old_ctx_error_free_old_param:
1061                 kfree(old_ucontext_param);
1062 old_ctx_error_free_param:
1063                 kfree(ucontext_param);
1064 old_ctx_end:
1065                 return ret;
1066         }
1067         case LTTNG_KERNEL_CONTEXT:
1068         {
1069                 struct lttng_kernel_context ucontext_param;
1070
1071                 if (copy_from_user(&ucontext_param,
1072                                 (struct lttng_kernel_context __user *) arg,
1073                                 sizeof(ucontext_param)))
1074                         return -EFAULT;
1075                 return lttng_abi_add_context(file,
1076                                 &ucontext_param,
1077                                 &channel->ctx, channel->session);
1078         }
1079         case LTTNG_KERNEL_OLD_ENABLE:
1080         case LTTNG_KERNEL_ENABLE:
1081                 return lttng_channel_enable(channel);
1082         case LTTNG_KERNEL_OLD_DISABLE:
1083         case LTTNG_KERNEL_DISABLE:
1084                 return lttng_channel_disable(channel);
1085         default:
1086                 return -ENOIOCTLCMD;
1087         }
1088
1089 }
1090
1091 /**
1092  *      lttng_metadata_ioctl - lttng syscall through ioctl
1093  *
1094  *      @file: the file
1095  *      @cmd: the command
1096  *      @arg: command arg
1097  *
1098  *      This ioctl implements lttng commands:
1099  *      LTTNG_KERNEL_STREAM
1100  *              Returns an event stream file descriptor or failure.
1101  *
1102  * Channel and event file descriptors also hold a reference on the session.
1103  */
1104 static
1105 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1106 {
1107         switch (cmd) {
1108         case LTTNG_KERNEL_OLD_STREAM:
1109         case LTTNG_KERNEL_STREAM:
1110                 return lttng_abi_open_metadata_stream(file);
1111         default:
1112                 return -ENOIOCTLCMD;
1113         }
1114 }
1115
1116 /**
1117  *      lttng_channel_poll - lttng stream addition/removal monitoring
1118  *
1119  *      @file: the file
1120  *      @wait: poll table
1121  */
1122 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1123 {
1124         struct lttng_channel *channel = file->private_data;
1125         unsigned int mask = 0;
1126
1127         if (file->f_mode & FMODE_READ) {
1128                 poll_wait_set_exclusive(wait);
1129                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1130                           wait);
1131
1132                 if (channel->ops->is_disabled(channel->chan))
1133                         return POLLERR;
1134                 if (channel->ops->is_finalized(channel->chan))
1135                         return POLLHUP;
1136                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1137                         return POLLIN | POLLRDNORM;
1138                 return 0;
1139         }
1140         return mask;
1141
1142 }
1143
1144 static
1145 int lttng_channel_release(struct inode *inode, struct file *file)
1146 {
1147         struct lttng_channel *channel = file->private_data;
1148
1149         if (channel)
1150                 fput(channel->session->file);
1151         return 0;
1152 }
1153
1154 static
1155 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1156 {
1157         struct lttng_channel *channel = file->private_data;
1158
1159         if (channel) {
1160                 lttng_metadata_channel_destroy(channel);
1161                 fput(channel->session->file);
1162         }
1163
1164         return 0;
1165 }
1166
1167 static const struct file_operations lttng_channel_fops = {
1168         .owner = THIS_MODULE,
1169         .release = lttng_channel_release,
1170         .poll = lttng_channel_poll,
1171         .unlocked_ioctl = lttng_channel_ioctl,
1172 #ifdef CONFIG_COMPAT
1173         .compat_ioctl = lttng_channel_ioctl,
1174 #endif
1175 };
1176
1177 static const struct file_operations lttng_metadata_fops = {
1178         .owner = THIS_MODULE,
1179         .release = lttng_metadata_channel_release,
1180         .unlocked_ioctl = lttng_metadata_ioctl,
1181 #ifdef CONFIG_COMPAT
1182         .compat_ioctl = lttng_metadata_ioctl,
1183 #endif
1184 };
1185
1186 /**
1187  *      lttng_event_ioctl - lttng syscall through ioctl
1188  *
1189  *      @file: the file
1190  *      @cmd: the command
1191  *      @arg: command arg
1192  *
1193  *      This ioctl implements lttng commands:
1194  *      LTTNG_KERNEL_CONTEXT
1195  *              Prepend a context field to each record of this event
1196  *      LTTNG_KERNEL_ENABLE
1197  *              Enable recording for this event (weak enable)
1198  *      LTTNG_KERNEL_DISABLE
1199  *              Disable recording for this event (strong disable)
1200  */
1201 static
1202 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1203 {
1204         struct lttng_event *event = file->private_data;
1205
1206         switch (cmd) {
1207         case LTTNG_KERNEL_OLD_CONTEXT:
1208         {
1209                 struct lttng_kernel_context *ucontext_param;
1210                 struct lttng_kernel_old_context *old_ucontext_param;
1211                 int ret;
1212
1213                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1214                                 GFP_KERNEL);
1215                 if (!ucontext_param) {
1216                         ret = -ENOMEM;
1217                         goto old_ctx_end;
1218                 }
1219                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1220                                 GFP_KERNEL);
1221                 if (!old_ucontext_param) {
1222                         ret = -ENOMEM;
1223                         goto old_ctx_error_free_param;
1224                 }
1225
1226                 if (copy_from_user(old_ucontext_param,
1227                                         (struct lttng_kernel_old_context __user *) arg,
1228                                         sizeof(struct lttng_kernel_old_context))) {
1229                         ret = -EFAULT;
1230                         goto old_ctx_error_free_old_param;
1231                 }
1232                 ucontext_param->ctx = old_ucontext_param->ctx;
1233                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1234                                 sizeof(ucontext_param->padding));
1235                 /* only type that uses the union */
1236                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1237                         ucontext_param->u.perf_counter.type =
1238                                 old_ucontext_param->u.perf_counter.type;
1239                         ucontext_param->u.perf_counter.config =
1240                                 old_ucontext_param->u.perf_counter.config;
1241                         memcpy(ucontext_param->u.perf_counter.name,
1242                                         old_ucontext_param->u.perf_counter.name,
1243                                         sizeof(ucontext_param->u.perf_counter.name));
1244                 }
1245
1246                 ret = lttng_abi_add_context(file,
1247                                 ucontext_param,
1248                                 &event->ctx, event->chan->session);
1249
1250 old_ctx_error_free_old_param:
1251                 kfree(old_ucontext_param);
1252 old_ctx_error_free_param:
1253                 kfree(ucontext_param);
1254 old_ctx_end:
1255                 return ret;
1256         }
1257         case LTTNG_KERNEL_CONTEXT:
1258         {
1259                 struct lttng_kernel_context ucontext_param;
1260
1261                 if (copy_from_user(&ucontext_param,
1262                                         (struct lttng_kernel_context __user *) arg,
1263                                         sizeof(ucontext_param)))
1264                         return -EFAULT;
1265                 return lttng_abi_add_context(file,
1266                                 &ucontext_param,
1267                                 &event->ctx, event->chan->session);
1268         }
1269         case LTTNG_KERNEL_OLD_ENABLE:
1270         case LTTNG_KERNEL_ENABLE:
1271                 return lttng_event_enable(event);
1272         case LTTNG_KERNEL_OLD_DISABLE:
1273         case LTTNG_KERNEL_DISABLE:
1274                 return lttng_event_disable(event);
1275         default:
1276                 return -ENOIOCTLCMD;
1277         }
1278 }
1279
1280 static
1281 int lttng_event_release(struct inode *inode, struct file *file)
1282 {
1283         struct lttng_event *event = file->private_data;
1284
1285         if (event)
1286                 fput(event->chan->file);
1287         return 0;
1288 }
1289
1290 /* TODO: filter control ioctl */
1291 static const struct file_operations lttng_event_fops = {
1292         .owner = THIS_MODULE,
1293         .release = lttng_event_release,
1294         .unlocked_ioctl = lttng_event_ioctl,
1295 #ifdef CONFIG_COMPAT
1296         .compat_ioctl = lttng_event_ioctl,
1297 #endif
1298 };
1299
1300 int __init lttng_abi_init(void)
1301 {
1302         int ret = 0;
1303
1304         wrapper_vmalloc_sync_all();
1305         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1306                                         &lttng_fops, NULL);
1307
1308         if (!lttng_proc_dentry) {
1309                 printk(KERN_ERR "Error creating LTTng control file\n");
1310                 ret = -ENOMEM;
1311                 goto error;
1312         }
1313 error:
1314         return ret;
1315 }
1316
1317 void __exit lttng_abi_exit(void)
1318 {
1319         if (lttng_proc_dentry)
1320                 remove_proc_entry("lttng", NULL);
1321 }