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 <linux/err.h>
  47 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  48 #include "wrapper/ringbuffer/vfs.h"
  49 #include "wrapper/ringbuffer/backend.h"
  50 #include "wrapper/ringbuffer/frontend.h"
  51 #include "wrapper/poll.h"
  52 #include "lttng-abi.h"
  53 #include "lttng-abi-old.h"
  54 #include "lttng-events.h"
  55 #include "lttng-tracer.h"
  56
  57 /*
  58  * This is LTTng's own personal way to create a system call as an external
  59  * module. We use ioctl() on /proc/lttng.
  60  */
  61
  62 static struct proc_dir_entry *lttng_proc_dentry;
  63 static const struct file_operations lttng_fops;
  64 static const struct file_operations lttng_session_fops;
  65 static const struct file_operations lttng_channel_fops;
  66 static const struct file_operations lttng_metadata_fops;
  67 static const struct file_operations lttng_event_fops;
  68
  69 /*
  70  * Teardown management: opened file descriptors keep a refcount on the module,
  71  * so it can only exit when all file descriptors are closed.
  72  */
  73
  74 static
  75 int lttng_abi_create_session(void)
  76 {
  77         struct lttng_session *session;
  78         struct file *session_file;
  79         int session_fd, ret;
  80
  81         session = lttng_session_create();
  82         if (!session)
  83                 return -ENOMEM;
  84         session_fd = get_unused_fd();
  85         if (session_fd < 0) {
  86                 ret = session_fd;
  87                 goto fd_error;
  88         }
  89         session_file = anon_inode_getfile("[lttng_session]",
  90                                           &lttng_session_fops,
  91                                           session, O_RDWR);
  92         if (IS_ERR(session_file)) {
  93                 ret = PTR_ERR(session_file);
  94                 goto file_error;
  95         }
  96         session->file = session_file;
  97         fd_install(session_fd, session_file);
  98         return session_fd;
  99
 100 file_error:
 101         put_unused_fd(session_fd);
 102 fd_error:
 103         lttng_session_destroy(session);
 104         return ret;
 105 }
 106
 107 static
 108 int lttng_abi_tracepoint_list(void)
 109 {
 110         struct file *tracepoint_list_file;
 111         int file_fd, ret;
 112
 113         file_fd = get_unused_fd();
 114         if (file_fd < 0) {
 115                 ret = file_fd;
 116                 goto fd_error;
 117         }
 118
 119         tracepoint_list_file = anon_inode_getfile("[lttng_session]",
 120                                           &lttng_tracepoint_list_fops,
 121                                           NULL, O_RDWR);
 122         if (IS_ERR(tracepoint_list_file)) {
 123                 ret = PTR_ERR(tracepoint_list_file);
 124                 goto file_error;
 125         }
 126         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 127         if (ret < 0)
 128                 goto open_error;
 129         fd_install(file_fd, tracepoint_list_file);
 130         if (file_fd < 0) {
 131                 ret = file_fd;
 132                 goto fd_error;
 133         }
 134         return file_fd;
 135
 136 open_error:
 137         fput(tracepoint_list_file);
 138 file_error:
 139         put_unused_fd(file_fd);
 140 fd_error:
 141         return ret;
 142 }
 143
 144 static
 145 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 146 {
 147         v->major = LTTNG_MODULES_MAJOR_VERSION;
 148         v->minor = LTTNG_MODULES_MINOR_VERSION;
 149         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 150 }
 151
 152 static
 153 long lttng_abi_add_context(struct file *file,
 154         struct lttng_kernel_context *context_param,
 155         struct lttng_ctx **ctx, struct lttng_session *session)
 156 {
 157
 158         if (session->been_active)
 159                 return -EPERM;
 160
 161         switch (context_param->ctx) {
 162         case LTTNG_KERNEL_CONTEXT_PID:
 163                 return lttng_add_pid_to_ctx(ctx);
 164         case LTTNG_KERNEL_CONTEXT_PRIO:
 165                 return lttng_add_prio_to_ctx(ctx);
 166         case LTTNG_KERNEL_CONTEXT_NICE:
 167                 return lttng_add_nice_to_ctx(ctx);
 168         case LTTNG_KERNEL_CONTEXT_VPID:
 169                 return lttng_add_vpid_to_ctx(ctx);
 170         case LTTNG_KERNEL_CONTEXT_TID:
 171                 return lttng_add_tid_to_ctx(ctx);
 172         case LTTNG_KERNEL_CONTEXT_VTID:
 173                 return lttng_add_vtid_to_ctx(ctx);
 174         case LTTNG_KERNEL_CONTEXT_PPID:
 175                 return lttng_add_ppid_to_ctx(ctx);
 176         case LTTNG_KERNEL_CONTEXT_VPPID:
 177                 return lttng_add_vppid_to_ctx(ctx);
 178         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 179                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 180                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 181                                 context_param->u.perf_counter.config,
 182                                 context_param->u.perf_counter.name,
 183                                 ctx);
 184         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 185                 return lttng_add_procname_to_ctx(ctx);
 186         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 187                 return lttng_add_hostname_to_ctx(ctx);
 188         default:
 189                 return -EINVAL;
 190         }
 191 }
 192
 193 /**
 194  *      lttng_ioctl - lttng syscall through ioctl
 195  *
 196  *      @file: the file
 197  *      @cmd: the command
 198  *      @arg: command arg
 199  *
 200  *      This ioctl implements lttng commands:
 201  *      LTTNG_KERNEL_SESSION
 202  *              Returns a LTTng trace session file descriptor
 203  *      LTTNG_KERNEL_TRACER_VERSION
 204  *              Returns the LTTng kernel tracer version
 205  *      LTTNG_KERNEL_TRACEPOINT_LIST
 206  *              Returns a file descriptor listing available tracepoints
 207  *      LTTNG_KERNEL_WAIT_QUIESCENT
 208  *              Returns after all previously running probes have completed
 209  *
 210  * The returned session will be deleted when its file descriptor is closed.
 211  */
 212 static
 213 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 214 {
 215         switch (cmd) {
 216         case LTTNG_KERNEL_OLD_SESSION:
 217         case LTTNG_KERNEL_SESSION:
 218                 return lttng_abi_create_session();
 219         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 220         {
 221                 struct lttng_kernel_tracer_version v;
 222                 struct lttng_kernel_old_tracer_version oldv;
 223                 struct lttng_kernel_old_tracer_version *uversion =
 224                         (struct lttng_kernel_old_tracer_version __user *) arg;
 225
 226                 lttng_abi_tracer_version(&v);
 227                 oldv.major = v.major;
 228                 oldv.minor = v.minor;
 229                 oldv.patchlevel = v.patchlevel;
 230
 231                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 232                         return -EFAULT;
 233                 return 0;
 234         }
 235         case LTTNG_KERNEL_TRACER_VERSION:
 236         {
 237                 struct lttng_kernel_tracer_version version;
 238                 struct lttng_kernel_tracer_version *uversion =
 239                         (struct lttng_kernel_tracer_version __user *) arg;
 240
 241                 lttng_abi_tracer_version(&version);
 242
 243                 if (copy_to_user(uversion, &version, sizeof(version)))
 244                         return -EFAULT;
 245                 return 0;
 246         }
 247         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 248         case LTTNG_KERNEL_TRACEPOINT_LIST:
 249                 return lttng_abi_tracepoint_list();
 250         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 251         case LTTNG_KERNEL_WAIT_QUIESCENT:
 252                 synchronize_trace();
 253                 return 0;
 254         case LTTNG_KERNEL_OLD_CALIBRATE:
 255         {
 256                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 257                         (struct lttng_kernel_old_calibrate __user *) arg;
 258                 struct lttng_kernel_old_calibrate old_calibrate;
 259                 struct lttng_kernel_calibrate calibrate;
 260                 int ret;
 261
 262                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 263                         return -EFAULT;
 264                 calibrate.type = old_calibrate.type;
 265                 ret = lttng_calibrate(&calibrate);
 266                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 267                         return -EFAULT;
 268                 return ret;
 269         }
 270         case LTTNG_KERNEL_CALIBRATE:
 271         {
 272                 struct lttng_kernel_calibrate __user *ucalibrate =
 273                         (struct lttng_kernel_calibrate __user *) arg;
 274                 struct lttng_kernel_calibrate calibrate;
 275                 int ret;
 276
 277                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 278                         return -EFAULT;
 279                 ret = lttng_calibrate(&calibrate);
 280                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 281                         return -EFAULT;
 282                 return ret;
 283         }
 284         default:
 285                 return -ENOIOCTLCMD;
 286         }
 287 }
 288
 289 static const struct file_operations lttng_fops = {
 290         .owner = THIS_MODULE,
 291         .unlocked_ioctl = lttng_ioctl,
 292 #ifdef CONFIG_COMPAT
 293         .compat_ioctl = lttng_ioctl,
 294 #endif
 295 };
 296
 297 static
 298 int lttng_abi_create_channel(struct file *session_file,
 299                              struct lttng_kernel_channel *chan_param,
 300                              enum channel_type channel_type)
 301 {
 302         struct lttng_session *session = session_file->private_data;
 303         const struct file_operations *fops = NULL;
 304         const char *transport_name;
 305         struct lttng_channel *chan;
 306         struct file *chan_file;
 307         int chan_fd;
 308         int ret = 0;
 309
 310         chan_fd = get_unused_fd();
 311         if (chan_fd < 0) {
 312                 ret = chan_fd;
 313                 goto fd_error;
 314         }
 315         switch (channel_type) {
 316         case PER_CPU_CHANNEL:
 317                 fops = &lttng_channel_fops;
 318                 break;
 319         case METADATA_CHANNEL:
 320                 fops = &lttng_metadata_fops;
 321                 break;
 322         }
 323
 324         chan_file = anon_inode_getfile("[lttng_channel]",
 325                                        fops,
 326                                        NULL, O_RDWR);
 327         if (IS_ERR(chan_file)) {
 328                 ret = PTR_ERR(chan_file);
 329                 goto file_error;
 330         }
 331         switch (channel_type) {
 332         case PER_CPU_CHANNEL:
 333                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 334                         transport_name = chan_param->overwrite ?
 335                                 "relay-overwrite" : "relay-discard";
 336                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 337                         transport_name = chan_param->overwrite ?
 338                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 339                 } else {
 340                         return -EINVAL;
 341                 }
 342                 break;
 343         case METADATA_CHANNEL:
 344                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 345                         transport_name = "relay-metadata";
 346                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 347                         transport_name = "relay-metadata-mmap";
 348                 else
 349                         return -EINVAL;
 350                 break;
 351         default:
 352                 transport_name = "<unknown>";
 353                 break;
 354         }
 355         /*
 356          * We tolerate no failure path after channel creation. It will stay
 357          * invariant for the rest of the session.
 358          */
 359         chan = lttng_channel_create(session, transport_name, NULL,
 360                                   chan_param->subbuf_size,
 361                                   chan_param->num_subbuf,
 362                                   chan_param->switch_timer_interval,
 363                                   chan_param->read_timer_interval,
 364                                   channel_type);
 365         if (!chan) {
 366                 ret = -EINVAL;
 367                 goto chan_error;
 368         }
 369         chan->file = chan_file;
 370         chan_file->private_data = chan;
 371         fd_install(chan_fd, chan_file);
 372         atomic_long_inc(&session_file->f_count);
 373
 374         return chan_fd;
 375
 376 chan_error:
 377         fput(chan_file);
 378 file_error:
 379         put_unused_fd(chan_fd);
 380 fd_error:
 381         return ret;
 382 }
 383
 384 /**
 385  *      lttng_session_ioctl - lttng session fd ioctl
 386  *
 387  *      @file: the file
 388  *      @cmd: the command
 389  *      @arg: command arg
 390  *
 391  *      This ioctl implements lttng commands:
 392  *      LTTNG_KERNEL_CHANNEL
 393  *              Returns a LTTng channel file descriptor
 394  *      LTTNG_KERNEL_ENABLE
 395  *              Enables tracing for a session (weak enable)
 396  *      LTTNG_KERNEL_DISABLE
 397  *              Disables tracing for a session (strong disable)
 398  *      LTTNG_KERNEL_METADATA
 399  *              Returns a LTTng metadata file descriptor
 400  *
 401  * The returned channel will be deleted when its file descriptor is closed.
 402  */
 403 static
 404 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 405 {
 406         struct lttng_session *session = file->private_data;
 407
 408         switch (cmd) {
 409         case LTTNG_KERNEL_OLD_CHANNEL:
 410         {
 411                 struct lttng_kernel_channel chan_param;
 412                 struct lttng_kernel_old_channel old_chan_param;
 413
 414                 if (copy_from_user(&old_chan_param,
 415                                 (struct lttng_kernel_old_channel __user *) arg,
 416                                 sizeof(struct lttng_kernel_old_channel)))
 417                         return -EFAULT;
 418                 chan_param.overwrite = old_chan_param.overwrite;
 419                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 420                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 421                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 422                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 423                 chan_param.output = old_chan_param.output;
 424
 425                 return lttng_abi_create_channel(file, &chan_param,
 426                                 PER_CPU_CHANNEL);
 427         }
 428         case LTTNG_KERNEL_CHANNEL:
 429         {
 430                 struct lttng_kernel_channel chan_param;
 431
 432                 if (copy_from_user(&chan_param,
 433                                 (struct lttng_kernel_channel __user *) arg,
 434                                 sizeof(struct lttng_kernel_channel)))
 435                         return -EFAULT;
 436                 return lttng_abi_create_channel(file, &chan_param,
 437                                 PER_CPU_CHANNEL);
 438         }
 439         case LTTNG_KERNEL_OLD_SESSION_START:
 440         case LTTNG_KERNEL_OLD_ENABLE:
 441         case LTTNG_KERNEL_SESSION_START:
 442         case LTTNG_KERNEL_ENABLE:
 443                 return lttng_session_enable(session);
 444         case LTTNG_KERNEL_OLD_SESSION_STOP:
 445         case LTTNG_KERNEL_OLD_DISABLE:
 446         case LTTNG_KERNEL_SESSION_STOP:
 447         case LTTNG_KERNEL_DISABLE:
 448                 return lttng_session_disable(session);
 449         case LTTNG_KERNEL_OLD_METADATA:
 450         {
 451                 struct lttng_kernel_channel chan_param;
 452                 struct lttng_kernel_old_channel old_chan_param;
 453
 454                 if (copy_from_user(&old_chan_param,
 455                                 (struct lttng_kernel_old_channel __user *) arg,
 456                                 sizeof(struct lttng_kernel_old_channel)))
 457                         return -EFAULT;
 458                 chan_param.overwrite = old_chan_param.overwrite;
 459                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 460                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 461                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 462                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 463                 chan_param.output = old_chan_param.output;
 464
 465                 return lttng_abi_create_channel(file, &chan_param,
 466                                 METADATA_CHANNEL);
 467         }
 468         case LTTNG_KERNEL_METADATA:
 469         {
 470                 struct lttng_kernel_channel chan_param;
 471
 472                 if (copy_from_user(&chan_param,
 473                                         (struct lttng_kernel_channel __user *) arg,
 474                                         sizeof(struct lttng_kernel_channel)))
 475                         return -EFAULT;
 476                 return lttng_abi_create_channel(file, &chan_param,
 477                                 METADATA_CHANNEL);
 478         }
 479         default:
 480                 return -ENOIOCTLCMD;
 481         }
 482 }
 483
 484 /*
 485  * Called when the last file reference is dropped.
 486  *
 487  * Big fat note: channels and events are invariant for the whole session after
 488  * their creation. So this session destruction also destroys all channel and
 489  * event structures specific to this session (they are not destroyed when their
 490  * individual file is released).
 491  */
 492 static
 493 int lttng_session_release(struct inode *inode, struct file *file)
 494 {
 495         struct lttng_session *session = file->private_data;
 496
 497         if (session)
 498                 lttng_session_destroy(session);
 499         return 0;
 500 }
 501
 502 static const struct file_operations lttng_session_fops = {
 503         .owner = THIS_MODULE,
 504         .release = lttng_session_release,
 505         .unlocked_ioctl = lttng_session_ioctl,
 506 #ifdef CONFIG_COMPAT
 507         .compat_ioctl = lttng_session_ioctl,
 508 #endif
 509 };
 510
 511 /**
 512  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 513  *      @filp: the file
 514  *      @wait: poll table
 515  *
 516  *      Handles the poll operations for the metadata channels.
 517  */
 518 static
 519 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 520                 poll_table *wait)
 521 {
 522         struct lttng_metadata_stream *stream = filp->private_data;
 523         struct lib_ring_buffer *buf = stream->priv;
 524         int finalized;
 525         unsigned int mask = 0;
 526
 527         if (filp->f_mode & FMODE_READ) {
 528                 poll_wait_set_exclusive(wait);
 529                 poll_wait(filp, &stream->read_wait, wait);
 530
 531                 finalized = stream->finalized;
 532
 533                 /*
 534                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 535                  * ordering finalized load before offsets loads.
 536                  */
 537                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 538
 539                 if (finalized)
 540                         mask |= POLLHUP;
 541
 542                 if (stream->metadata_cache->metadata_written >
 543                                 stream->metadata_out)
 544                         mask |= POLLIN;
 545         }
 546
 547         return mask;
 548 }
 549
 550 static
 551 int lttng_metadata_ring_buffer_ioctl_get_next_subbuf(struct file *filp,
 552                 unsigned int cmd, unsigned long arg)
 553 {
 554         struct lttng_metadata_stream *stream = filp->private_data;
 555         struct lib_ring_buffer *buf = stream->priv;
 556         struct channel *chan = buf->backend.chan;
 557         int ret;
 558
 559         ret = lttng_metadata_output_channel(stream, chan);
 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 /*
 675  * This is not used by anonymous file descriptors. This code is left
 676  * there if we ever want to implement an inode with open() operation.
 677  */
 678 static
 679 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 680 {
 681         struct lttng_metadata_stream *stream = inode->i_private;
 682         struct lib_ring_buffer *buf = stream->priv;
 683
 684         file->private_data = buf;
 685         /*
 686          * Since life-time of metadata cache differs from that of
 687          * session, we need to keep our own reference on the transport.
 688          */
 689         if (!try_module_get(stream->transport->owner)) {
 690                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 691                 return -EBUSY;
 692         }
 693         return lib_ring_buffer_open(inode, file, buf);
 694 }
 695
 696 static
 697 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 698 {
 699         struct lttng_metadata_stream *stream = file->private_data;
 700         struct lib_ring_buffer *buf = stream->priv;
 701
 702         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 703         module_put(stream->transport->owner);
 704         return lib_ring_buffer_release(inode, file, buf);
 705 }
 706
 707 static
 708 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 709                 struct pipe_inode_info *pipe, size_t len,
 710                 unsigned int flags)
 711 {
 712         struct lttng_metadata_stream *stream = in->private_data;
 713         struct lib_ring_buffer *buf = stream->priv;
 714
 715         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 716                         flags, buf);
 717 }
 718
 719 static
 720 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 721                 struct vm_area_struct *vma)
 722 {
 723         struct lttng_metadata_stream *stream = filp->private_data;
 724         struct lib_ring_buffer *buf = stream->priv;
 725
 726         return lib_ring_buffer_mmap(filp, vma, buf);
 727 }
 728
 729 static
 730 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 731         .owner = THIS_MODULE,
 732         .open = lttng_metadata_ring_buffer_open,
 733         .release = lttng_metadata_ring_buffer_release,
 734         .poll = lttng_metadata_ring_buffer_poll,
 735         .splice_read = lttng_metadata_ring_buffer_splice_read,
 736         .mmap = lttng_metadata_ring_buffer_mmap,
 737         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 738         .llseek = vfs_lib_ring_buffer_no_llseek,
 739 #ifdef CONFIG_COMPAT
 740         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 741 #endif
 742 };
 743
 744 static
 745 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 746                 const struct file_operations *fops)
 747 {
 748         int stream_fd, ret;
 749         struct file *stream_file;
 750
 751         stream_fd = get_unused_fd();
 752         if (stream_fd < 0) {
 753                 ret = stream_fd;
 754                 goto fd_error;
 755         }
 756         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 757                         stream_priv, O_RDWR);
 758         if (IS_ERR(stream_file)) {
 759                 ret = PTR_ERR(stream_file);
 760                 goto file_error;
 761         }
 762         /*
 763          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 764          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 765          * file descriptor, so we set FMODE_PREAD here.
 766          */
 767         stream_file->f_mode |= FMODE_PREAD;
 768         fd_install(stream_fd, stream_file);
 769         /*
 770          * The stream holds a reference to the channel within the generic ring
 771          * buffer library, so no need to hold a refcount on the channel and
 772          * session files here.
 773          */
 774         return stream_fd;
 775
 776 file_error:
 777         put_unused_fd(stream_fd);
 778 fd_error:
 779         return ret;
 780 }
 781
 782 static
 783 int lttng_abi_open_stream(struct file *channel_file)
 784 {
 785         struct lttng_channel *channel = channel_file->private_data;
 786         struct lib_ring_buffer *buf;
 787         int ret;
 788         void *stream_priv;
 789
 790         buf = channel->ops->buffer_read_open(channel->chan);
 791         if (!buf)
 792                 return -ENOENT;
 793
 794         stream_priv = buf;
 795         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 796                         &lib_ring_buffer_file_operations);
 797         if (ret < 0)
 798                 goto fd_error;
 799
 800         return ret;
 801
 802 fd_error:
 803         channel->ops->buffer_read_close(buf);
 804         return ret;
 805 }
 806
 807 static
 808 int lttng_abi_open_metadata_stream(struct file *channel_file)
 809 {
 810         struct lttng_channel *channel = channel_file->private_data;
 811         struct lttng_session *session = channel->session;
 812         struct lib_ring_buffer *buf;
 813         int ret;
 814         struct lttng_metadata_stream *metadata_stream;
 815         void *stream_priv;
 816
 817         buf = channel->ops->buffer_read_open(channel->chan);
 818         if (!buf)
 819                 return -ENOENT;
 820
 821         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 822                         GFP_KERNEL);
 823         if (!metadata_stream) {
 824                 ret = -ENOMEM;
 825                 goto nomem;
 826         }
 827         metadata_stream->metadata_cache = session->metadata_cache;
 828         init_waitqueue_head(&metadata_stream->read_wait);
 829         metadata_stream->priv = buf;
 830         stream_priv = metadata_stream;
 831         metadata_stream->transport = channel->transport;
 832
 833         /*
 834          * Since life-time of metadata cache differs from that of
 835          * session, we need to keep our own reference on the transport.
 836          */
 837         if (!try_module_get(metadata_stream->transport->owner)) {
 838                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 839                 ret = -EINVAL;
 840                 goto notransport;
 841         }
 842
 843         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 844                         &lttng_metadata_ring_buffer_file_operations);
 845         if (ret < 0)
 846                 goto fd_error;
 847
 848         kref_get(&session->metadata_cache->refcount);
 849         list_add(&metadata_stream->list,
 850                 &session->metadata_cache->metadata_stream);
 851         return ret;
 852
 853 fd_error:
 854         module_put(metadata_stream->transport->owner);
 855 notransport:
 856         kfree(metadata_stream);
 857 nomem:
 858         channel->ops->buffer_read_close(buf);
 859         return ret;
 860 }
 861
 862 static
 863 int lttng_abi_create_event(struct file *channel_file,
 864                            struct lttng_kernel_event *event_param)
 865 {
 866         struct lttng_channel *channel = channel_file->private_data;
 867         struct lttng_event *event;
 868         int event_fd, ret;
 869         struct file *event_file;
 870
 871         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 872         switch (event_param->instrumentation) {
 873         case LTTNG_KERNEL_KRETPROBE:
 874                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 875                 break;
 876         case LTTNG_KERNEL_KPROBE:
 877                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 878                 break;
 879         case LTTNG_KERNEL_FUNCTION:
 880                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 881                 break;
 882         default:
 883                 break;
 884         }
 885         switch (event_param->instrumentation) {
 886         default:
 887                 event_fd = get_unused_fd();
 888                 if (event_fd < 0) {
 889                         ret = event_fd;
 890                         goto fd_error;
 891                 }
 892                 event_file = anon_inode_getfile("[lttng_event]",
 893                                                 &lttng_event_fops,
 894                                                 NULL, O_RDWR);
 895                 if (IS_ERR(event_file)) {
 896                         ret = PTR_ERR(event_file);
 897                         goto file_error;
 898                 }
 899                 /*
 900                  * We tolerate no failure path after event creation. It
 901                  * will stay invariant for the rest of the session.
 902                  */
 903                 event = lttng_event_create(channel, event_param, NULL, NULL);
 904                 WARN_ON_ONCE(!event);
 905                 if (IS_ERR(event)) {
 906                         ret = PTR_ERR(event);
 907                         goto event_error;
 908                 }
 909                 event_file->private_data = event;
 910                 fd_install(event_fd, event_file);
 911                 /* The event holds a reference on the channel */
 912                 atomic_long_inc(&channel_file->f_count);
 913                 break;
 914         case LTTNG_KERNEL_SYSCALL:
 915                 /*
 916                  * Only all-syscall tracing supported for now.
 917                  */
 918                 if (event_param->name[0] != '\0')
 919                         return -EINVAL;
 920                 ret = lttng_syscalls_register(channel, NULL);
 921                 if (ret)
 922                         goto fd_error;
 923                 event_fd = 0;
 924                 break;
 925         }
 926         return event_fd;
 927
 928 event_error:
 929         fput(event_file);
 930 file_error:
 931         put_unused_fd(event_fd);
 932 fd_error:
 933         return ret;
 934 }
 935
 936 /**
 937  *      lttng_channel_ioctl - lttng syscall through ioctl
 938  *
 939  *      @file: the file
 940  *      @cmd: the command
 941  *      @arg: command arg
 942  *
 943  *      This ioctl implements lttng commands:
 944  *      LTTNG_KERNEL_STREAM
 945  *              Returns an event stream file descriptor or failure.
 946  *              (typically, one event stream records events from one CPU)
 947  *      LTTNG_KERNEL_EVENT
 948  *              Returns an event file descriptor or failure.
 949  *      LTTNG_KERNEL_CONTEXT
 950  *              Prepend a context field to each event in the channel
 951  *      LTTNG_KERNEL_ENABLE
 952  *              Enable recording for events in this channel (weak enable)
 953  *      LTTNG_KERNEL_DISABLE
 954  *              Disable recording for events in this channel (strong disable)
 955  *
 956  * Channel and event file descriptors also hold a reference on the session.
 957  */
 958 static
 959 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 960 {
 961         struct lttng_channel *channel = file->private_data;
 962
 963         switch (cmd) {
 964         case LTTNG_KERNEL_OLD_STREAM:
 965         case LTTNG_KERNEL_STREAM:
 966                 return lttng_abi_open_stream(file);
 967         case LTTNG_KERNEL_OLD_EVENT:
 968         {
 969                 struct lttng_kernel_event *uevent_param;
 970                 struct lttng_kernel_old_event *old_uevent_param;
 971                 int ret;
 972
 973                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
 974                                 GFP_KERNEL);
 975                 if (!uevent_param) {
 976                         ret = -ENOMEM;
 977                         goto old_event_end;
 978                 }
 979                 old_uevent_param = kmalloc(
 980                                 sizeof(struct lttng_kernel_old_event),
 981                                 GFP_KERNEL);
 982                 if (!old_uevent_param) {
 983                         ret = -ENOMEM;
 984                         goto old_event_error_free_param;
 985                 }
 986                 if (copy_from_user(old_uevent_param,
 987                                 (struct lttng_kernel_old_event __user *) arg,
 988                                 sizeof(struct lttng_kernel_old_event))) {
 989                         ret = -EFAULT;
 990                         goto old_event_error_free_old_param;
 991                 }
 992
 993                 memcpy(uevent_param->name, old_uevent_param->name,
 994                                 sizeof(uevent_param->name));
 995                 uevent_param->instrumentation =
 996                         old_uevent_param->instrumentation;
 997
 998                 switch (old_uevent_param->instrumentation) {
 999                 case LTTNG_KERNEL_KPROBE:
1000                         uevent_param->u.kprobe.addr =
1001                                 old_uevent_param->u.kprobe.addr;
1002                         uevent_param->u.kprobe.offset =
1003                                 old_uevent_param->u.kprobe.offset;
1004                         memcpy(uevent_param->u.kprobe.symbol_name,
1005                                 old_uevent_param->u.kprobe.symbol_name,
1006                                 sizeof(uevent_param->u.kprobe.symbol_name));
1007                         break;
1008                 case LTTNG_KERNEL_KRETPROBE:
1009                         uevent_param->u.kretprobe.addr =
1010                                 old_uevent_param->u.kretprobe.addr;
1011                         uevent_param->u.kretprobe.offset =
1012                                 old_uevent_param->u.kretprobe.offset;
1013                         memcpy(uevent_param->u.kretprobe.symbol_name,
1014                                 old_uevent_param->u.kretprobe.symbol_name,
1015                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1016                         break;
1017                 case LTTNG_KERNEL_FUNCTION:
1018                         memcpy(uevent_param->u.ftrace.symbol_name,
1019                                         old_uevent_param->u.ftrace.symbol_name,
1020                                         sizeof(uevent_param->u.ftrace.symbol_name));
1021                         break;
1022                 default:
1023                         break;
1024                 }
1025                 ret = lttng_abi_create_event(file, uevent_param);
1026
1027 old_event_error_free_old_param:
1028                 kfree(old_uevent_param);
1029 old_event_error_free_param:
1030                 kfree(uevent_param);
1031 old_event_end:
1032                 return ret;
1033         }
1034         case LTTNG_KERNEL_EVENT:
1035         {
1036                 struct lttng_kernel_event uevent_param;
1037
1038                 if (copy_from_user(&uevent_param,
1039                                 (struct lttng_kernel_event __user *) arg,
1040                                 sizeof(uevent_param)))
1041                         return -EFAULT;
1042                 return lttng_abi_create_event(file, &uevent_param);
1043         }
1044         case LTTNG_KERNEL_OLD_CONTEXT:
1045         {
1046                 struct lttng_kernel_context *ucontext_param;
1047                 struct lttng_kernel_old_context *old_ucontext_param;
1048                 int ret;
1049
1050                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1051                                 GFP_KERNEL);
1052                 if (!ucontext_param) {
1053                         ret = -ENOMEM;
1054                         goto old_ctx_end;
1055                 }
1056                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1057                                 GFP_KERNEL);
1058                 if (!old_ucontext_param) {
1059                         ret = -ENOMEM;
1060                         goto old_ctx_error_free_param;
1061                 }
1062
1063                 if (copy_from_user(old_ucontext_param,
1064                                 (struct lttng_kernel_old_context __user *) arg,
1065                                 sizeof(struct lttng_kernel_old_context))) {
1066                         ret = -EFAULT;
1067                         goto old_ctx_error_free_old_param;
1068                 }
1069                 ucontext_param->ctx = old_ucontext_param->ctx;
1070                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1071                                 sizeof(ucontext_param->padding));
1072                 /* only type that uses the union */
1073                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1074                         ucontext_param->u.perf_counter.type =
1075                                 old_ucontext_param->u.perf_counter.type;
1076                         ucontext_param->u.perf_counter.config =
1077                                 old_ucontext_param->u.perf_counter.config;
1078                         memcpy(ucontext_param->u.perf_counter.name,
1079                                 old_ucontext_param->u.perf_counter.name,
1080                                 sizeof(ucontext_param->u.perf_counter.name));
1081                 }
1082
1083                 ret = lttng_abi_add_context(file,
1084                                 ucontext_param,
1085                                 &channel->ctx, channel->session);
1086
1087 old_ctx_error_free_old_param:
1088                 kfree(old_ucontext_param);
1089 old_ctx_error_free_param:
1090                 kfree(ucontext_param);
1091 old_ctx_end:
1092                 return ret;
1093         }
1094         case LTTNG_KERNEL_CONTEXT:
1095         {
1096                 struct lttng_kernel_context ucontext_param;
1097
1098                 if (copy_from_user(&ucontext_param,
1099                                 (struct lttng_kernel_context __user *) arg,
1100                                 sizeof(ucontext_param)))
1101                         return -EFAULT;
1102                 return lttng_abi_add_context(file,
1103                                 &ucontext_param,
1104                                 &channel->ctx, channel->session);
1105         }
1106         case LTTNG_KERNEL_OLD_ENABLE:
1107         case LTTNG_KERNEL_ENABLE:
1108                 return lttng_channel_enable(channel);
1109         case LTTNG_KERNEL_OLD_DISABLE:
1110         case LTTNG_KERNEL_DISABLE:
1111                 return lttng_channel_disable(channel);
1112         default:
1113                 return -ENOIOCTLCMD;
1114         }
1115
1116 }
1117
1118 /**
1119  *      lttng_metadata_ioctl - lttng syscall through ioctl
1120  *
1121  *      @file: the file
1122  *      @cmd: the command
1123  *      @arg: command arg
1124  *
1125  *      This ioctl implements lttng commands:
1126  *      LTTNG_KERNEL_STREAM
1127  *              Returns an event stream file descriptor or failure.
1128  *
1129  * Channel and event file descriptors also hold a reference on the session.
1130  */
1131 static
1132 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1133 {
1134         switch (cmd) {
1135         case LTTNG_KERNEL_OLD_STREAM:
1136         case LTTNG_KERNEL_STREAM:
1137                 return lttng_abi_open_metadata_stream(file);
1138         default:
1139                 return -ENOIOCTLCMD;
1140         }
1141 }
1142
1143 /**
1144  *      lttng_channel_poll - lttng stream addition/removal monitoring
1145  *
1146  *      @file: the file
1147  *      @wait: poll table
1148  */
1149 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1150 {
1151         struct lttng_channel *channel = file->private_data;
1152         unsigned int mask = 0;
1153
1154         if (file->f_mode & FMODE_READ) {
1155                 poll_wait_set_exclusive(wait);
1156                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1157                           wait);
1158
1159                 if (channel->ops->is_disabled(channel->chan))
1160                         return POLLERR;
1161                 if (channel->ops->is_finalized(channel->chan))
1162                         return POLLHUP;
1163                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1164                         return POLLIN | POLLRDNORM;
1165                 return 0;
1166         }
1167         return mask;
1168
1169 }
1170
1171 static
1172 int lttng_channel_release(struct inode *inode, struct file *file)
1173 {
1174         struct lttng_channel *channel = file->private_data;
1175
1176         if (channel)
1177                 fput(channel->session->file);
1178         return 0;
1179 }
1180
1181 static
1182 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1183 {
1184         struct lttng_channel *channel = file->private_data;
1185
1186         if (channel) {
1187                 lttng_metadata_channel_destroy(channel);
1188                 fput(channel->session->file);
1189         }
1190
1191         return 0;
1192 }
1193
1194 static const struct file_operations lttng_channel_fops = {
1195         .owner = THIS_MODULE,
1196         .release = lttng_channel_release,
1197         .poll = lttng_channel_poll,
1198         .unlocked_ioctl = lttng_channel_ioctl,
1199 #ifdef CONFIG_COMPAT
1200         .compat_ioctl = lttng_channel_ioctl,
1201 #endif
1202 };
1203
1204 static const struct file_operations lttng_metadata_fops = {
1205         .owner = THIS_MODULE,
1206         .release = lttng_metadata_channel_release,
1207         .unlocked_ioctl = lttng_metadata_ioctl,
1208 #ifdef CONFIG_COMPAT
1209         .compat_ioctl = lttng_metadata_ioctl,
1210 #endif
1211 };
1212
1213 /**
1214  *      lttng_event_ioctl - lttng syscall through ioctl
1215  *
1216  *      @file: the file
1217  *      @cmd: the command
1218  *      @arg: command arg
1219  *
1220  *      This ioctl implements lttng commands:
1221  *      LTTNG_KERNEL_CONTEXT
1222  *              Prepend a context field to each record of this event
1223  *      LTTNG_KERNEL_ENABLE
1224  *              Enable recording for this event (weak enable)
1225  *      LTTNG_KERNEL_DISABLE
1226  *              Disable recording for this event (strong disable)
1227  */
1228 static
1229 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1230 {
1231         struct lttng_event *event = file->private_data;
1232
1233         switch (cmd) {
1234         case LTTNG_KERNEL_OLD_CONTEXT:
1235         {
1236                 struct lttng_kernel_context *ucontext_param;
1237                 struct lttng_kernel_old_context *old_ucontext_param;
1238                 int ret;
1239
1240                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1241                                 GFP_KERNEL);
1242                 if (!ucontext_param) {
1243                         ret = -ENOMEM;
1244                         goto old_ctx_end;
1245                 }
1246                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1247                                 GFP_KERNEL);
1248                 if (!old_ucontext_param) {
1249                         ret = -ENOMEM;
1250                         goto old_ctx_error_free_param;
1251                 }
1252
1253                 if (copy_from_user(old_ucontext_param,
1254                                         (struct lttng_kernel_old_context __user *) arg,
1255                                         sizeof(struct lttng_kernel_old_context))) {
1256                         ret = -EFAULT;
1257                         goto old_ctx_error_free_old_param;
1258                 }
1259                 ucontext_param->ctx = old_ucontext_param->ctx;
1260                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1261                                 sizeof(ucontext_param->padding));
1262                 /* only type that uses the union */
1263                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1264                         ucontext_param->u.perf_counter.type =
1265                                 old_ucontext_param->u.perf_counter.type;
1266                         ucontext_param->u.perf_counter.config =
1267                                 old_ucontext_param->u.perf_counter.config;
1268                         memcpy(ucontext_param->u.perf_counter.name,
1269                                         old_ucontext_param->u.perf_counter.name,
1270                                         sizeof(ucontext_param->u.perf_counter.name));
1271                 }
1272
1273                 ret = lttng_abi_add_context(file,
1274                                 ucontext_param,
1275                                 &event->ctx, event->chan->session);
1276
1277 old_ctx_error_free_old_param:
1278                 kfree(old_ucontext_param);
1279 old_ctx_error_free_param:
1280                 kfree(ucontext_param);
1281 old_ctx_end:
1282                 return ret;
1283         }
1284         case LTTNG_KERNEL_CONTEXT:
1285         {
1286                 struct lttng_kernel_context ucontext_param;
1287
1288                 if (copy_from_user(&ucontext_param,
1289                                         (struct lttng_kernel_context __user *) arg,
1290                                         sizeof(ucontext_param)))
1291                         return -EFAULT;
1292                 return lttng_abi_add_context(file,
1293                                 &ucontext_param,
1294                                 &event->ctx, event->chan->session);
1295         }
1296         case LTTNG_KERNEL_OLD_ENABLE:
1297         case LTTNG_KERNEL_ENABLE:
1298                 return lttng_event_enable(event);
1299         case LTTNG_KERNEL_OLD_DISABLE:
1300         case LTTNG_KERNEL_DISABLE:
1301                 return lttng_event_disable(event);
1302         default:
1303                 return -ENOIOCTLCMD;
1304         }
1305 }
1306
1307 static
1308 int lttng_event_release(struct inode *inode, struct file *file)
1309 {
1310         struct lttng_event *event = file->private_data;
1311
1312         if (event)
1313                 fput(event->chan->file);
1314         return 0;
1315 }
1316
1317 /* TODO: filter control ioctl */
1318 static const struct file_operations lttng_event_fops = {
1319         .owner = THIS_MODULE,
1320         .release = lttng_event_release,
1321         .unlocked_ioctl = lttng_event_ioctl,
1322 #ifdef CONFIG_COMPAT
1323         .compat_ioctl = lttng_event_ioctl,
1324 #endif
1325 };
1326
1327 int __init lttng_abi_init(void)
1328 {
1329         int ret = 0;
1330
1331         wrapper_vmalloc_sync_all();
1332         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1333                                         &lttng_fops, NULL);
1334
1335         if (!lttng_proc_dentry) {
1336                 printk(KERN_ERR "Error creating LTTng control file\n");
1337                 ret = -ENOMEM;
1338                 goto error;
1339         }
1340 error:
1341         return ret;
1342 }
1343
1344 void __exit lttng_abi_exit(void)
1345 {
1346         if (lttng_proc_dentry)
1347                 remove_proc_entry("lttng", NULL);
1348 }