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         int ret;
 557
 558         ret = lttng_metadata_output_channel(stream, chan);
 559         if (ret > 0) {
 560                 lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 561                 ret = 0;
 562         }
 563         return ret;
 564 }
 565
 566 static
 567 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 568                 unsigned int cmd, unsigned long arg)
 569 {
 570         struct lttng_metadata_stream *stream = filp->private_data;
 571
 572         stream->metadata_out = stream->metadata_in;
 573 }
 574
 575 static
 576 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 577                 unsigned int cmd, unsigned long arg)
 578 {
 579         int ret;
 580         struct lttng_metadata_stream *stream = filp->private_data;
 581         struct lib_ring_buffer *buf = stream->priv;
 582
 583         switch (cmd) {
 584         case RING_BUFFER_GET_NEXT_SUBBUF:
 585         {
 586                 ret = lttng_metadata_ring_buffer_ioctl_get_next_subbuf(filp,
 587                                 cmd, arg);
 588                 if (ret < 0)
 589                         goto err;
 590                 break;
 591         }
 592         case RING_BUFFER_GET_SUBBUF:
 593         {
 594                 /*
 595                  * Random access is not allowed for metadata channel.
 596                  */
 597                 return -ENOSYS;
 598         }
 599         default:
 600                 break;
 601         }
 602         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 603
 604         /* Performing lib ring buffer ioctl after our own. */
 605         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 606         if (ret < 0)
 607                 goto err;
 608
 609         switch (cmd) {
 610         case RING_BUFFER_PUT_NEXT_SUBBUF:
 611         {
 612                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 613                                 cmd, arg);
 614                 break;
 615         }
 616         default:
 617                 break;
 618         }
 619 err:
 620         return ret;
 621 }
 622
 623 #ifdef CONFIG_COMPAT
 624 static
 625 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 626                 unsigned int cmd, unsigned long arg)
 627 {
 628         int ret;
 629         struct lttng_metadata_stream *stream = filp->private_data;
 630         struct lib_ring_buffer *buf = stream->priv;
 631
 632         switch (cmd) {
 633         case RING_BUFFER_GET_NEXT_SUBBUF:
 634         {
 635                 ret = lttng_metadata_ring_buffer_ioctl_get_next_subbuf(filp,
 636                                 cmd, arg);
 637                 if (ret < 0)
 638                         goto err;
 639                 break;
 640         }
 641         case RING_BUFFER_GET_SUBBUF:
 642         {
 643                 /*
 644                  * Random access is not allowed for metadata channel.
 645                  */
 646                 return -ENOSYS;
 647         }
 648         default:
 649                 break;
 650         }
 651         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 652
 653         /* Performing lib ring buffer ioctl after our own. */
 654         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 655         if (ret < 0)
 656                 goto err;
 657
 658         switch (cmd) {
 659         case RING_BUFFER_PUT_NEXT_SUBBUF:
 660         {
 661                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 662                                 cmd, arg);
 663                 break;
 664         }
 665         default:
 666                 break;
 667         }
 668 err:
 669         return ret;
 670 }
 671 #endif
 672
 673 /*
 674  * This is not used by anonymous file descriptors. This code is left
 675  * there if we ever want to implement an inode with open() operation.
 676  */
 677 static
 678 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 679 {
 680         struct lttng_metadata_stream *stream = inode->i_private;
 681         struct lib_ring_buffer *buf = stream->priv;
 682
 683         file->private_data = buf;
 684         /*
 685          * Since life-time of metadata cache differs from that of
 686          * session, we need to keep our own reference on the transport.
 687          */
 688         if (!try_module_get(stream->transport->owner)) {
 689                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 690                 return -EBUSY;
 691         }
 692         return lib_ring_buffer_open(inode, file, buf);
 693 }
 694
 695 static
 696 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 697 {
 698         struct lttng_metadata_stream *stream = file->private_data;
 699         struct lib_ring_buffer *buf = stream->priv;
 700
 701         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 702         module_put(stream->transport->owner);
 703         return lib_ring_buffer_release(inode, file, buf);
 704 }
 705
 706 static
 707 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 708                 struct pipe_inode_info *pipe, size_t len,
 709                 unsigned int flags)
 710 {
 711         struct lttng_metadata_stream *stream = in->private_data;
 712         struct lib_ring_buffer *buf = stream->priv;
 713
 714         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 715                         flags, buf);
 716 }
 717
 718 static
 719 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 720                 struct vm_area_struct *vma)
 721 {
 722         struct lttng_metadata_stream *stream = filp->private_data;
 723         struct lib_ring_buffer *buf = stream->priv;
 724
 725         return lib_ring_buffer_mmap(filp, vma, buf);
 726 }
 727
 728 static
 729 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 730         .owner = THIS_MODULE,
 731         .open = lttng_metadata_ring_buffer_open,
 732         .release = lttng_metadata_ring_buffer_release,
 733         .poll = lttng_metadata_ring_buffer_poll,
 734         .splice_read = lttng_metadata_ring_buffer_splice_read,
 735         .mmap = lttng_metadata_ring_buffer_mmap,
 736         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 737         .llseek = vfs_lib_ring_buffer_no_llseek,
 738 #ifdef CONFIG_COMPAT
 739         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 740 #endif
 741 };
 742
 743 static
 744 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 745                 const struct file_operations *fops)
 746 {
 747         int stream_fd, ret;
 748         struct file *stream_file;
 749
 750         stream_fd = get_unused_fd();
 751         if (stream_fd < 0) {
 752                 ret = stream_fd;
 753                 goto fd_error;
 754         }
 755         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 756                         stream_priv, O_RDWR);
 757         if (IS_ERR(stream_file)) {
 758                 ret = PTR_ERR(stream_file);
 759                 goto file_error;
 760         }
 761         /*
 762          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 763          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 764          * file descriptor, so we set FMODE_PREAD here.
 765          */
 766         stream_file->f_mode |= FMODE_PREAD;
 767         fd_install(stream_fd, stream_file);
 768         /*
 769          * The stream holds a reference to the channel within the generic ring
 770          * buffer library, so no need to hold a refcount on the channel and
 771          * session files here.
 772          */
 773         return stream_fd;
 774
 775 file_error:
 776         put_unused_fd(stream_fd);
 777 fd_error:
 778         return ret;
 779 }
 780
 781 static
 782 int lttng_abi_open_stream(struct file *channel_file)
 783 {
 784         struct lttng_channel *channel = channel_file->private_data;
 785         struct lib_ring_buffer *buf;
 786         int ret;
 787         void *stream_priv;
 788
 789         buf = channel->ops->buffer_read_open(channel->chan);
 790         if (!buf)
 791                 return -ENOENT;
 792
 793         stream_priv = buf;
 794         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 795                         &lib_ring_buffer_file_operations);
 796         if (ret < 0)
 797                 goto fd_error;
 798
 799         return ret;
 800
 801 fd_error:
 802         channel->ops->buffer_read_close(buf);
 803         return ret;
 804 }
 805
 806 static
 807 int lttng_abi_open_metadata_stream(struct file *channel_file)
 808 {
 809         struct lttng_channel *channel = channel_file->private_data;
 810         struct lttng_session *session = channel->session;
 811         struct lib_ring_buffer *buf;
 812         int ret;
 813         struct lttng_metadata_stream *metadata_stream;
 814         void *stream_priv;
 815
 816         buf = channel->ops->buffer_read_open(channel->chan);
 817         if (!buf)
 818                 return -ENOENT;
 819
 820         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 821                         GFP_KERNEL);
 822         if (!metadata_stream) {
 823                 ret = -ENOMEM;
 824                 goto nomem;
 825         }
 826         metadata_stream->metadata_cache = session->metadata_cache;
 827         init_waitqueue_head(&metadata_stream->read_wait);
 828         metadata_stream->priv = buf;
 829         stream_priv = metadata_stream;
 830         metadata_stream->transport = channel->transport;
 831
 832         /*
 833          * Since life-time of metadata cache differs from that of
 834          * session, we need to keep our own reference on the transport.
 835          */
 836         if (!try_module_get(metadata_stream->transport->owner)) {
 837                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 838                 ret = -EINVAL;
 839                 goto notransport;
 840         }
 841
 842         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 843                         &lttng_metadata_ring_buffer_file_operations);
 844         if (ret < 0)
 845                 goto fd_error;
 846
 847         kref_get(&session->metadata_cache->refcount);
 848         list_add(&metadata_stream->list,
 849                 &session->metadata_cache->metadata_stream);
 850         return ret;
 851
 852 fd_error:
 853         module_put(metadata_stream->transport->owner);
 854 notransport:
 855         kfree(metadata_stream);
 856 nomem:
 857         channel->ops->buffer_read_close(buf);
 858         return ret;
 859 }
 860
 861 static
 862 int lttng_abi_create_event(struct file *channel_file,
 863                            struct lttng_kernel_event *event_param)
 864 {
 865         struct lttng_channel *channel = channel_file->private_data;
 866         struct lttng_event *event;
 867         int event_fd, ret;
 868         struct file *event_file;
 869
 870         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 871         switch (event_param->instrumentation) {
 872         case LTTNG_KERNEL_KRETPROBE:
 873                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 874                 break;
 875         case LTTNG_KERNEL_KPROBE:
 876                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 877                 break;
 878         case LTTNG_KERNEL_FUNCTION:
 879                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 880                 break;
 881         default:
 882                 break;
 883         }
 884         switch (event_param->instrumentation) {
 885         default:
 886                 event_fd = get_unused_fd();
 887                 if (event_fd < 0) {
 888                         ret = event_fd;
 889                         goto fd_error;
 890                 }
 891                 event_file = anon_inode_getfile("[lttng_event]",
 892                                                 &lttng_event_fops,
 893                                                 NULL, O_RDWR);
 894                 if (IS_ERR(event_file)) {
 895                         ret = PTR_ERR(event_file);
 896                         goto file_error;
 897                 }
 898                 /*
 899                  * We tolerate no failure path after event creation. It
 900                  * will stay invariant for the rest of the session.
 901                  */
 902                 event = lttng_event_create(channel, event_param, NULL, NULL);
 903                 if (!event) {
 904                         ret = -EINVAL;
 905                         goto event_error;
 906                 }
 907                 event_file->private_data = event;
 908                 fd_install(event_fd, event_file);
 909                 /* The event holds a reference on the channel */
 910                 atomic_long_inc(&channel_file->f_count);
 911                 break;
 912         case LTTNG_KERNEL_SYSCALL:
 913                 /*
 914                  * Only all-syscall tracing supported for now.
 915                  */
 916                 if (event_param->name[0] != '\0')
 917                         return -EINVAL;
 918                 ret = lttng_syscalls_register(channel, NULL);
 919                 if (ret)
 920                         goto fd_error;
 921                 event_fd = 0;
 922                 break;
 923         }
 924         return event_fd;
 925
 926 event_error:
 927         fput(event_file);
 928 file_error:
 929         put_unused_fd(event_fd);
 930 fd_error:
 931         return ret;
 932 }
 933
 934 /**
 935  *      lttng_channel_ioctl - lttng syscall through ioctl
 936  *
 937  *      @file: the file
 938  *      @cmd: the command
 939  *      @arg: command arg
 940  *
 941  *      This ioctl implements lttng commands:
 942  *      LTTNG_KERNEL_STREAM
 943  *              Returns an event stream file descriptor or failure.
 944  *              (typically, one event stream records events from one CPU)
 945  *      LTTNG_KERNEL_EVENT
 946  *              Returns an event file descriptor or failure.
 947  *      LTTNG_KERNEL_CONTEXT
 948  *              Prepend a context field to each event in the channel
 949  *      LTTNG_KERNEL_ENABLE
 950  *              Enable recording for events in this channel (weak enable)
 951  *      LTTNG_KERNEL_DISABLE
 952  *              Disable recording for events in this channel (strong disable)
 953  *
 954  * Channel and event file descriptors also hold a reference on the session.
 955  */
 956 static
 957 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 958 {
 959         struct lttng_channel *channel = file->private_data;
 960
 961         switch (cmd) {
 962         case LTTNG_KERNEL_OLD_STREAM:
 963         case LTTNG_KERNEL_STREAM:
 964                 return lttng_abi_open_stream(file);
 965         case LTTNG_KERNEL_OLD_EVENT:
 966         {
 967                 struct lttng_kernel_event *uevent_param;
 968                 struct lttng_kernel_old_event *old_uevent_param;
 969                 int ret;
 970
 971                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
 972                                 GFP_KERNEL);
 973                 if (!uevent_param) {
 974                         ret = -ENOMEM;
 975                         goto old_event_end;
 976                 }
 977                 old_uevent_param = kmalloc(
 978                                 sizeof(struct lttng_kernel_old_event),
 979                                 GFP_KERNEL);
 980                 if (!old_uevent_param) {
 981                         ret = -ENOMEM;
 982                         goto old_event_error_free_param;
 983                 }
 984                 if (copy_from_user(old_uevent_param,
 985                                 (struct lttng_kernel_old_event __user *) arg,
 986                                 sizeof(struct lttng_kernel_old_event))) {
 987                         ret = -EFAULT;
 988                         goto old_event_error_free_old_param;
 989                 }
 990
 991                 memcpy(uevent_param->name, old_uevent_param->name,
 992                                 sizeof(uevent_param->name));
 993                 uevent_param->instrumentation =
 994                         old_uevent_param->instrumentation;
 995
 996                 switch (old_uevent_param->instrumentation) {
 997                 case LTTNG_KERNEL_KPROBE:
 998                         uevent_param->u.kprobe.addr =
 999                                 old_uevent_param->u.kprobe.addr;
1000                         uevent_param->u.kprobe.offset =
1001                                 old_uevent_param->u.kprobe.offset;
1002                         memcpy(uevent_param->u.kprobe.symbol_name,
1003                                 old_uevent_param->u.kprobe.symbol_name,
1004                                 sizeof(uevent_param->u.kprobe.symbol_name));
1005                         break;
1006                 case LTTNG_KERNEL_KRETPROBE:
1007                         uevent_param->u.kretprobe.addr =
1008                                 old_uevent_param->u.kretprobe.addr;
1009                         uevent_param->u.kretprobe.offset =
1010                                 old_uevent_param->u.kretprobe.offset;
1011                         memcpy(uevent_param->u.kretprobe.symbol_name,
1012                                 old_uevent_param->u.kretprobe.symbol_name,
1013                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1014                         break;
1015                 case LTTNG_KERNEL_FUNCTION:
1016                         memcpy(uevent_param->u.ftrace.symbol_name,
1017                                         old_uevent_param->u.ftrace.symbol_name,
1018                                         sizeof(uevent_param->u.ftrace.symbol_name));
1019                         break;
1020                 default:
1021                         break;
1022                 }
1023                 ret = lttng_abi_create_event(file, uevent_param);
1024
1025 old_event_error_free_old_param:
1026                 kfree(old_uevent_param);
1027 old_event_error_free_param:
1028                 kfree(uevent_param);
1029 old_event_end:
1030                 return ret;
1031         }
1032         case LTTNG_KERNEL_EVENT:
1033         {
1034                 struct lttng_kernel_event uevent_param;
1035
1036                 if (copy_from_user(&uevent_param,
1037                                 (struct lttng_kernel_event __user *) arg,
1038                                 sizeof(uevent_param)))
1039                         return -EFAULT;
1040                 return lttng_abi_create_event(file, &uevent_param);
1041         }
1042         case LTTNG_KERNEL_OLD_CONTEXT:
1043         {
1044                 struct lttng_kernel_context *ucontext_param;
1045                 struct lttng_kernel_old_context *old_ucontext_param;
1046                 int ret;
1047
1048                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1049                                 GFP_KERNEL);
1050                 if (!ucontext_param) {
1051                         ret = -ENOMEM;
1052                         goto old_ctx_end;
1053                 }
1054                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1055                                 GFP_KERNEL);
1056                 if (!old_ucontext_param) {
1057                         ret = -ENOMEM;
1058                         goto old_ctx_error_free_param;
1059                 }
1060
1061                 if (copy_from_user(old_ucontext_param,
1062                                 (struct lttng_kernel_old_context __user *) arg,
1063                                 sizeof(struct lttng_kernel_old_context))) {
1064                         ret = -EFAULT;
1065                         goto old_ctx_error_free_old_param;
1066                 }
1067                 ucontext_param->ctx = old_ucontext_param->ctx;
1068                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1069                                 sizeof(ucontext_param->padding));
1070                 /* only type that uses the union */
1071                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1072                         ucontext_param->u.perf_counter.type =
1073                                 old_ucontext_param->u.perf_counter.type;
1074                         ucontext_param->u.perf_counter.config =
1075                                 old_ucontext_param->u.perf_counter.config;
1076                         memcpy(ucontext_param->u.perf_counter.name,
1077                                 old_ucontext_param->u.perf_counter.name,
1078                                 sizeof(ucontext_param->u.perf_counter.name));
1079                 }
1080
1081                 ret = lttng_abi_add_context(file,
1082                                 ucontext_param,
1083                                 &channel->ctx, channel->session);
1084
1085 old_ctx_error_free_old_param:
1086                 kfree(old_ucontext_param);
1087 old_ctx_error_free_param:
1088                 kfree(ucontext_param);
1089 old_ctx_end:
1090                 return ret;
1091         }
1092         case LTTNG_KERNEL_CONTEXT:
1093         {
1094                 struct lttng_kernel_context ucontext_param;
1095
1096                 if (copy_from_user(&ucontext_param,
1097                                 (struct lttng_kernel_context __user *) arg,
1098                                 sizeof(ucontext_param)))
1099                         return -EFAULT;
1100                 return lttng_abi_add_context(file,
1101                                 &ucontext_param,
1102                                 &channel->ctx, channel->session);
1103         }
1104         case LTTNG_KERNEL_OLD_ENABLE:
1105         case LTTNG_KERNEL_ENABLE:
1106                 return lttng_channel_enable(channel);
1107         case LTTNG_KERNEL_OLD_DISABLE:
1108         case LTTNG_KERNEL_DISABLE:
1109                 return lttng_channel_disable(channel);
1110         default:
1111                 return -ENOIOCTLCMD;
1112         }
1113
1114 }
1115
1116 /**
1117  *      lttng_metadata_ioctl - lttng syscall through ioctl
1118  *
1119  *      @file: the file
1120  *      @cmd: the command
1121  *      @arg: command arg
1122  *
1123  *      This ioctl implements lttng commands:
1124  *      LTTNG_KERNEL_STREAM
1125  *              Returns an event stream file descriptor or failure.
1126  *
1127  * Channel and event file descriptors also hold a reference on the session.
1128  */
1129 static
1130 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1131 {
1132         switch (cmd) {
1133         case LTTNG_KERNEL_OLD_STREAM:
1134         case LTTNG_KERNEL_STREAM:
1135                 return lttng_abi_open_metadata_stream(file);
1136         default:
1137                 return -ENOIOCTLCMD;
1138         }
1139 }
1140
1141 /**
1142  *      lttng_channel_poll - lttng stream addition/removal monitoring
1143  *
1144  *      @file: the file
1145  *      @wait: poll table
1146  */
1147 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1148 {
1149         struct lttng_channel *channel = file->private_data;
1150         unsigned int mask = 0;
1151
1152         if (file->f_mode & FMODE_READ) {
1153                 poll_wait_set_exclusive(wait);
1154                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1155                           wait);
1156
1157                 if (channel->ops->is_disabled(channel->chan))
1158                         return POLLERR;
1159                 if (channel->ops->is_finalized(channel->chan))
1160                         return POLLHUP;
1161                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1162                         return POLLIN | POLLRDNORM;
1163                 return 0;
1164         }
1165         return mask;
1166
1167 }
1168
1169 static
1170 int lttng_channel_release(struct inode *inode, struct file *file)
1171 {
1172         struct lttng_channel *channel = file->private_data;
1173
1174         if (channel)
1175                 fput(channel->session->file);
1176         return 0;
1177 }
1178
1179 static
1180 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1181 {
1182         struct lttng_channel *channel = file->private_data;
1183
1184         if (channel) {
1185                 lttng_metadata_channel_destroy(channel);
1186                 fput(channel->session->file);
1187         }
1188
1189         return 0;
1190 }
1191
1192 static const struct file_operations lttng_channel_fops = {
1193         .owner = THIS_MODULE,
1194         .release = lttng_channel_release,
1195         .poll = lttng_channel_poll,
1196         .unlocked_ioctl = lttng_channel_ioctl,
1197 #ifdef CONFIG_COMPAT
1198         .compat_ioctl = lttng_channel_ioctl,
1199 #endif
1200 };
1201
1202 static const struct file_operations lttng_metadata_fops = {
1203         .owner = THIS_MODULE,
1204         .release = lttng_metadata_channel_release,
1205         .unlocked_ioctl = lttng_metadata_ioctl,
1206 #ifdef CONFIG_COMPAT
1207         .compat_ioctl = lttng_metadata_ioctl,
1208 #endif
1209 };
1210
1211 /**
1212  *      lttng_event_ioctl - lttng syscall through ioctl
1213  *
1214  *      @file: the file
1215  *      @cmd: the command
1216  *      @arg: command arg
1217  *
1218  *      This ioctl implements lttng commands:
1219  *      LTTNG_KERNEL_CONTEXT
1220  *              Prepend a context field to each record of this event
1221  *      LTTNG_KERNEL_ENABLE
1222  *              Enable recording for this event (weak enable)
1223  *      LTTNG_KERNEL_DISABLE
1224  *              Disable recording for this event (strong disable)
1225  */
1226 static
1227 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1228 {
1229         struct lttng_event *event = file->private_data;
1230
1231         switch (cmd) {
1232         case LTTNG_KERNEL_OLD_CONTEXT:
1233         {
1234                 struct lttng_kernel_context *ucontext_param;
1235                 struct lttng_kernel_old_context *old_ucontext_param;
1236                 int ret;
1237
1238                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1239                                 GFP_KERNEL);
1240                 if (!ucontext_param) {
1241                         ret = -ENOMEM;
1242                         goto old_ctx_end;
1243                 }
1244                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1245                                 GFP_KERNEL);
1246                 if (!old_ucontext_param) {
1247                         ret = -ENOMEM;
1248                         goto old_ctx_error_free_param;
1249                 }
1250
1251                 if (copy_from_user(old_ucontext_param,
1252                                         (struct lttng_kernel_old_context __user *) arg,
1253                                         sizeof(struct lttng_kernel_old_context))) {
1254                         ret = -EFAULT;
1255                         goto old_ctx_error_free_old_param;
1256                 }
1257                 ucontext_param->ctx = old_ucontext_param->ctx;
1258                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1259                                 sizeof(ucontext_param->padding));
1260                 /* only type that uses the union */
1261                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1262                         ucontext_param->u.perf_counter.type =
1263                                 old_ucontext_param->u.perf_counter.type;
1264                         ucontext_param->u.perf_counter.config =
1265                                 old_ucontext_param->u.perf_counter.config;
1266                         memcpy(ucontext_param->u.perf_counter.name,
1267                                         old_ucontext_param->u.perf_counter.name,
1268                                         sizeof(ucontext_param->u.perf_counter.name));
1269                 }
1270
1271                 ret = lttng_abi_add_context(file,
1272                                 ucontext_param,
1273                                 &event->ctx, event->chan->session);
1274
1275 old_ctx_error_free_old_param:
1276                 kfree(old_ucontext_param);
1277 old_ctx_error_free_param:
1278                 kfree(ucontext_param);
1279 old_ctx_end:
1280                 return ret;
1281         }
1282         case LTTNG_KERNEL_CONTEXT:
1283         {
1284                 struct lttng_kernel_context ucontext_param;
1285
1286                 if (copy_from_user(&ucontext_param,
1287                                         (struct lttng_kernel_context __user *) arg,
1288                                         sizeof(ucontext_param)))
1289                         return -EFAULT;
1290                 return lttng_abi_add_context(file,
1291                                 &ucontext_param,
1292                                 &event->ctx, event->chan->session);
1293         }
1294         case LTTNG_KERNEL_OLD_ENABLE:
1295         case LTTNG_KERNEL_ENABLE:
1296                 return lttng_event_enable(event);
1297         case LTTNG_KERNEL_OLD_DISABLE:
1298         case LTTNG_KERNEL_DISABLE:
1299                 return lttng_event_disable(event);
1300         default:
1301                 return -ENOIOCTLCMD;
1302         }
1303 }
1304
1305 static
1306 int lttng_event_release(struct inode *inode, struct file *file)
1307 {
1308         struct lttng_event *event = file->private_data;
1309
1310         if (event)
1311                 fput(event->chan->file);
1312         return 0;
1313 }
1314
1315 /* TODO: filter control ioctl */
1316 static const struct file_operations lttng_event_fops = {
1317         .owner = THIS_MODULE,
1318         .release = lttng_event_release,
1319         .unlocked_ioctl = lttng_event_ioctl,
1320 #ifdef CONFIG_COMPAT
1321         .compat_ioctl = lttng_event_ioctl,
1322 #endif
1323 };
1324
1325 int __init lttng_abi_init(void)
1326 {
1327         int ret = 0;
1328
1329         wrapper_vmalloc_sync_all();
1330         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1331                                         &lttng_fops, NULL);
1332
1333         if (!lttng_proc_dentry) {
1334                 printk(KERN_ERR "Error creating LTTng control file\n");
1335                 ret = -ENOMEM;
1336                 goto error;
1337         }
1338 error:
1339         return ret;
1340 }
1341
1342 void __exit lttng_abi_exit(void)
1343 {
1344         if (lttng_proc_dentry)
1345                 remove_proc_entry("lttng", NULL);
1346 }