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 #include "lib/ringbuffer/frontend_types.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 static struct file_operations lttng_stream_ring_buffer_file_operations;
  69
  70 /*
  71  * Teardown management: opened file descriptors keep a refcount on the module,
  72  * so it can only exit when all file descriptors are closed.
  73  */
  74
  75 static
  76 int lttng_abi_create_session(void)
  77 {
  78         struct lttng_session *session;
  79         struct file *session_file;
  80         int session_fd, ret;
  81
  82         session = lttng_session_create();
  83         if (!session)
  84                 return -ENOMEM;
  85         session_fd = get_unused_fd();
  86         if (session_fd < 0) {
  87                 ret = session_fd;
  88                 goto fd_error;
  89         }
  90         session_file = anon_inode_getfile("[lttng_session]",
  91                                           &lttng_session_fops,
  92                                           session, O_RDWR);
  93         if (IS_ERR(session_file)) {
  94                 ret = PTR_ERR(session_file);
  95                 goto file_error;
  96         }
  97         session->file = session_file;
  98         fd_install(session_fd, session_file);
  99         return session_fd;
 100
 101 file_error:
 102         put_unused_fd(session_fd);
 103 fd_error:
 104         lttng_session_destroy(session);
 105         return ret;
 106 }
 107
 108 static
 109 int lttng_abi_tracepoint_list(void)
 110 {
 111         struct file *tracepoint_list_file;
 112         int file_fd, ret;
 113
 114         file_fd = get_unused_fd();
 115         if (file_fd < 0) {
 116                 ret = file_fd;
 117                 goto fd_error;
 118         }
 119
 120         tracepoint_list_file = anon_inode_getfile("[lttng_session]",
 121                                           &lttng_tracepoint_list_fops,
 122                                           NULL, O_RDWR);
 123         if (IS_ERR(tracepoint_list_file)) {
 124                 ret = PTR_ERR(tracepoint_list_file);
 125                 goto file_error;
 126         }
 127         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 128         if (ret < 0)
 129                 goto open_error;
 130         fd_install(file_fd, tracepoint_list_file);
 131         if (file_fd < 0) {
 132                 ret = file_fd;
 133                 goto fd_error;
 134         }
 135         return file_fd;
 136
 137 open_error:
 138         fput(tracepoint_list_file);
 139 file_error:
 140         put_unused_fd(file_fd);
 141 fd_error:
 142         return ret;
 143 }
 144
 145 static
 146 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 147 {
 148         v->major = LTTNG_MODULES_MAJOR_VERSION;
 149         v->minor = LTTNG_MODULES_MINOR_VERSION;
 150         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 151 }
 152
 153 static
 154 long lttng_abi_add_context(struct file *file,
 155         struct lttng_kernel_context *context_param,
 156         struct lttng_ctx **ctx, struct lttng_session *session)
 157 {
 158
 159         if (session->been_active)
 160                 return -EPERM;
 161
 162         switch (context_param->ctx) {
 163         case LTTNG_KERNEL_CONTEXT_PID:
 164                 return lttng_add_pid_to_ctx(ctx);
 165         case LTTNG_KERNEL_CONTEXT_PRIO:
 166                 return lttng_add_prio_to_ctx(ctx);
 167         case LTTNG_KERNEL_CONTEXT_NICE:
 168                 return lttng_add_nice_to_ctx(ctx);
 169         case LTTNG_KERNEL_CONTEXT_VPID:
 170                 return lttng_add_vpid_to_ctx(ctx);
 171         case LTTNG_KERNEL_CONTEXT_TID:
 172                 return lttng_add_tid_to_ctx(ctx);
 173         case LTTNG_KERNEL_CONTEXT_VTID:
 174                 return lttng_add_vtid_to_ctx(ctx);
 175         case LTTNG_KERNEL_CONTEXT_PPID:
 176                 return lttng_add_ppid_to_ctx(ctx);
 177         case LTTNG_KERNEL_CONTEXT_VPPID:
 178                 return lttng_add_vppid_to_ctx(ctx);
 179         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 180                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 181                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 182                                 context_param->u.perf_counter.config,
 183                                 context_param->u.perf_counter.name,
 184                                 ctx);
 185         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 186                 return lttng_add_procname_to_ctx(ctx);
 187         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 188                 return lttng_add_hostname_to_ctx(ctx);
 189         default:
 190                 return -EINVAL;
 191         }
 192 }
 193
 194 /**
 195  *      lttng_ioctl - lttng syscall through ioctl
 196  *
 197  *      @file: the file
 198  *      @cmd: the command
 199  *      @arg: command arg
 200  *
 201  *      This ioctl implements lttng commands:
 202  *      LTTNG_KERNEL_SESSION
 203  *              Returns a LTTng trace session file descriptor
 204  *      LTTNG_KERNEL_TRACER_VERSION
 205  *              Returns the LTTng kernel tracer version
 206  *      LTTNG_KERNEL_TRACEPOINT_LIST
 207  *              Returns a file descriptor listing available tracepoints
 208  *      LTTNG_KERNEL_WAIT_QUIESCENT
 209  *              Returns after all previously running probes have completed
 210  *
 211  * The returned session will be deleted when its file descriptor is closed.
 212  */
 213 static
 214 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 215 {
 216         switch (cmd) {
 217         case LTTNG_KERNEL_OLD_SESSION:
 218         case LTTNG_KERNEL_SESSION:
 219                 return lttng_abi_create_session();
 220         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 221         {
 222                 struct lttng_kernel_tracer_version v;
 223                 struct lttng_kernel_old_tracer_version oldv;
 224                 struct lttng_kernel_old_tracer_version *uversion =
 225                         (struct lttng_kernel_old_tracer_version __user *) arg;
 226
 227                 lttng_abi_tracer_version(&v);
 228                 oldv.major = v.major;
 229                 oldv.minor = v.minor;
 230                 oldv.patchlevel = v.patchlevel;
 231
 232                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 233                         return -EFAULT;
 234                 return 0;
 235         }
 236         case LTTNG_KERNEL_TRACER_VERSION:
 237         {
 238                 struct lttng_kernel_tracer_version version;
 239                 struct lttng_kernel_tracer_version *uversion =
 240                         (struct lttng_kernel_tracer_version __user *) arg;
 241
 242                 lttng_abi_tracer_version(&version);
 243
 244                 if (copy_to_user(uversion, &version, sizeof(version)))
 245                         return -EFAULT;
 246                 return 0;
 247         }
 248         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 249         case LTTNG_KERNEL_TRACEPOINT_LIST:
 250                 return lttng_abi_tracepoint_list();
 251         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 252         case LTTNG_KERNEL_WAIT_QUIESCENT:
 253                 synchronize_trace();
 254                 return 0;
 255         case LTTNG_KERNEL_OLD_CALIBRATE:
 256         {
 257                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 258                         (struct lttng_kernel_old_calibrate __user *) arg;
 259                 struct lttng_kernel_old_calibrate old_calibrate;
 260                 struct lttng_kernel_calibrate calibrate;
 261                 int ret;
 262
 263                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 264                         return -EFAULT;
 265                 calibrate.type = old_calibrate.type;
 266                 ret = lttng_calibrate(&calibrate);
 267                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 268                         return -EFAULT;
 269                 return ret;
 270         }
 271         case LTTNG_KERNEL_CALIBRATE:
 272         {
 273                 struct lttng_kernel_calibrate __user *ucalibrate =
 274                         (struct lttng_kernel_calibrate __user *) arg;
 275                 struct lttng_kernel_calibrate calibrate;
 276                 int ret;
 277
 278                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 279                         return -EFAULT;
 280                 ret = lttng_calibrate(&calibrate);
 281                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 282                         return -EFAULT;
 283                 return ret;
 284         }
 285         default:
 286                 return -ENOIOCTLCMD;
 287         }
 288 }
 289
 290 static const struct file_operations lttng_fops = {
 291         .owner = THIS_MODULE,
 292         .unlocked_ioctl = lttng_ioctl,
 293 #ifdef CONFIG_COMPAT
 294         .compat_ioctl = lttng_ioctl,
 295 #endif
 296 };
 297
 298 static
 299 int lttng_abi_create_channel(struct file *session_file,
 300                              struct lttng_kernel_channel *chan_param,
 301                              enum channel_type channel_type)
 302 {
 303         struct lttng_session *session = session_file->private_data;
 304         const struct file_operations *fops = NULL;
 305         const char *transport_name;
 306         struct lttng_channel *chan;
 307         struct file *chan_file;
 308         int chan_fd;
 309         int ret = 0;
 310
 311         chan_fd = get_unused_fd();
 312         if (chan_fd < 0) {
 313                 ret = chan_fd;
 314                 goto fd_error;
 315         }
 316         switch (channel_type) {
 317         case PER_CPU_CHANNEL:
 318                 fops = &lttng_channel_fops;
 319                 break;
 320         case METADATA_CHANNEL:
 321                 fops = &lttng_metadata_fops;
 322                 break;
 323         }
 324
 325         chan_file = anon_inode_getfile("[lttng_channel]",
 326                                        fops,
 327                                        NULL, O_RDWR);
 328         if (IS_ERR(chan_file)) {
 329                 ret = PTR_ERR(chan_file);
 330                 goto file_error;
 331         }
 332         switch (channel_type) {
 333         case PER_CPU_CHANNEL:
 334                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 335                         transport_name = chan_param->overwrite ?
 336                                 "relay-overwrite" : "relay-discard";
 337                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 338                         transport_name = chan_param->overwrite ?
 339                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 340                 } else {
 341                         return -EINVAL;
 342                 }
 343                 break;
 344         case METADATA_CHANNEL:
 345                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 346                         transport_name = "relay-metadata";
 347                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 348                         transport_name = "relay-metadata-mmap";
 349                 else
 350                         return -EINVAL;
 351                 break;
 352         default:
 353                 transport_name = "<unknown>";
 354                 break;
 355         }
 356         /*
 357          * We tolerate no failure path after channel creation. It will stay
 358          * invariant for the rest of the session.
 359          */
 360         chan = lttng_channel_create(session, transport_name, NULL,
 361                                   chan_param->subbuf_size,
 362                                   chan_param->num_subbuf,
 363                                   chan_param->switch_timer_interval,
 364                                   chan_param->read_timer_interval,
 365                                   channel_type);
 366         if (!chan) {
 367                 ret = -EINVAL;
 368                 goto chan_error;
 369         }
 370         chan->file = chan_file;
 371         chan_file->private_data = chan;
 372         fd_install(chan_fd, chan_file);
 373         atomic_long_inc(&session_file->f_count);
 374
 375         return chan_fd;
 376
 377 chan_error:
 378         fput(chan_file);
 379 file_error:
 380         put_unused_fd(chan_fd);
 381 fd_error:
 382         return ret;
 383 }
 384
 385 /**
 386  *      lttng_session_ioctl - lttng session fd ioctl
 387  *
 388  *      @file: the file
 389  *      @cmd: the command
 390  *      @arg: command arg
 391  *
 392  *      This ioctl implements lttng commands:
 393  *      LTTNG_KERNEL_CHANNEL
 394  *              Returns a LTTng channel file descriptor
 395  *      LTTNG_KERNEL_ENABLE
 396  *              Enables tracing for a session (weak enable)
 397  *      LTTNG_KERNEL_DISABLE
 398  *              Disables tracing for a session (strong disable)
 399  *      LTTNG_KERNEL_METADATA
 400  *              Returns a LTTng metadata file descriptor
 401  *
 402  * The returned channel will be deleted when its file descriptor is closed.
 403  */
 404 static
 405 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 406 {
 407         struct lttng_session *session = file->private_data;
 408
 409         switch (cmd) {
 410         case LTTNG_KERNEL_OLD_CHANNEL:
 411         {
 412                 struct lttng_kernel_channel chan_param;
 413                 struct lttng_kernel_old_channel old_chan_param;
 414
 415                 if (copy_from_user(&old_chan_param,
 416                                 (struct lttng_kernel_old_channel __user *) arg,
 417                                 sizeof(struct lttng_kernel_old_channel)))
 418                         return -EFAULT;
 419                 chan_param.overwrite = old_chan_param.overwrite;
 420                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 421                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 422                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 423                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 424                 chan_param.output = old_chan_param.output;
 425
 426                 return lttng_abi_create_channel(file, &chan_param,
 427                                 PER_CPU_CHANNEL);
 428         }
 429         case LTTNG_KERNEL_CHANNEL:
 430         {
 431                 struct lttng_kernel_channel chan_param;
 432
 433                 if (copy_from_user(&chan_param,
 434                                 (struct lttng_kernel_channel __user *) arg,
 435                                 sizeof(struct lttng_kernel_channel)))
 436                         return -EFAULT;
 437                 return lttng_abi_create_channel(file, &chan_param,
 438                                 PER_CPU_CHANNEL);
 439         }
 440         case LTTNG_KERNEL_OLD_SESSION_START:
 441         case LTTNG_KERNEL_OLD_ENABLE:
 442         case LTTNG_KERNEL_SESSION_START:
 443         case LTTNG_KERNEL_ENABLE:
 444                 return lttng_session_enable(session);
 445         case LTTNG_KERNEL_OLD_SESSION_STOP:
 446         case LTTNG_KERNEL_OLD_DISABLE:
 447         case LTTNG_KERNEL_SESSION_STOP:
 448         case LTTNG_KERNEL_DISABLE:
 449                 return lttng_session_disable(session);
 450         case LTTNG_KERNEL_OLD_METADATA:
 451         {
 452                 struct lttng_kernel_channel chan_param;
 453                 struct lttng_kernel_old_channel old_chan_param;
 454
 455                 if (copy_from_user(&old_chan_param,
 456                                 (struct lttng_kernel_old_channel __user *) arg,
 457                                 sizeof(struct lttng_kernel_old_channel)))
 458                         return -EFAULT;
 459                 chan_param.overwrite = old_chan_param.overwrite;
 460                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 461                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 462                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 463                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 464                 chan_param.output = old_chan_param.output;
 465
 466                 return lttng_abi_create_channel(file, &chan_param,
 467                                 METADATA_CHANNEL);
 468         }
 469         case LTTNG_KERNEL_METADATA:
 470         {
 471                 struct lttng_kernel_channel chan_param;
 472
 473                 if (copy_from_user(&chan_param,
 474                                         (struct lttng_kernel_channel __user *) arg,
 475                                         sizeof(struct lttng_kernel_channel)))
 476                         return -EFAULT;
 477                 return lttng_abi_create_channel(file, &chan_param,
 478                                 METADATA_CHANNEL);
 479         }
 480         default:
 481                 return -ENOIOCTLCMD;
 482         }
 483 }
 484
 485 /*
 486  * Called when the last file reference is dropped.
 487  *
 488  * Big fat note: channels and events are invariant for the whole session after
 489  * their creation. So this session destruction also destroys all channel and
 490  * event structures specific to this session (they are not destroyed when their
 491  * individual file is released).
 492  */
 493 static
 494 int lttng_session_release(struct inode *inode, struct file *file)
 495 {
 496         struct lttng_session *session = file->private_data;
 497
 498         if (session)
 499                 lttng_session_destroy(session);
 500         return 0;
 501 }
 502
 503 static const struct file_operations lttng_session_fops = {
 504         .owner = THIS_MODULE,
 505         .release = lttng_session_release,
 506         .unlocked_ioctl = lttng_session_ioctl,
 507 #ifdef CONFIG_COMPAT
 508         .compat_ioctl = lttng_session_ioctl,
 509 #endif
 510 };
 511
 512 /**
 513  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 514  *      @filp: the file
 515  *      @wait: poll table
 516  *
 517  *      Handles the poll operations for the metadata channels.
 518  */
 519 static
 520 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 521                 poll_table *wait)
 522 {
 523         struct lttng_metadata_stream *stream = filp->private_data;
 524         struct lib_ring_buffer *buf = stream->priv;
 525         int finalized;
 526         unsigned int mask = 0;
 527
 528         if (filp->f_mode & FMODE_READ) {
 529                 poll_wait_set_exclusive(wait);
 530                 poll_wait(filp, &stream->read_wait, wait);
 531
 532                 finalized = stream->finalized;
 533
 534                 /*
 535                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 536                  * ordering finalized load before offsets loads.
 537                  */
 538                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 539
 540                 if (finalized)
 541                         mask |= POLLHUP;
 542
 543                 if (stream->metadata_cache->metadata_written >
 544                                 stream->metadata_out)
 545                         mask |= POLLIN;
 546         }
 547
 548         return mask;
 549 }
 550
 551 static
 552 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 553                 unsigned int cmd, unsigned long arg)
 554 {
 555         struct lttng_metadata_stream *stream = filp->private_data;
 556
 557         stream->metadata_out = stream->metadata_in;
 558 }
 559
 560 static
 561 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 562                 unsigned int cmd, unsigned long arg)
 563 {
 564         int ret;
 565         struct lttng_metadata_stream *stream = filp->private_data;
 566         struct lib_ring_buffer *buf = stream->priv;
 567
 568         switch (cmd) {
 569         case RING_BUFFER_GET_NEXT_SUBBUF:
 570         {
 571                 struct lttng_metadata_stream *stream = filp->private_data;
 572                 struct lib_ring_buffer *buf = stream->priv;
 573                 struct channel *chan = buf->backend.chan;
 574
 575                 ret = lttng_metadata_output_channel(stream, chan);
 576                 if (ret > 0) {
 577                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 578                         ret = 0;
 579                 } else if (ret < 0)
 580                         goto err;
 581                 break;
 582         }
 583         case RING_BUFFER_GET_SUBBUF:
 584         {
 585                 /*
 586                  * Random access is not allowed for metadata channel.
 587                  */
 588                 return -ENOSYS;
 589         }
 590         case RING_BUFFER_FLUSH:
 591         {
 592                 struct lttng_metadata_stream *stream = filp->private_data;
 593                 struct lib_ring_buffer *buf = stream->priv;
 594                 struct channel *chan = buf->backend.chan;
 595
 596                 /*
 597                  * Before doing the actual ring buffer flush, write up to one
 598                  * packet of metadata in the ring buffer.
 599                  */
 600                 ret = lttng_metadata_output_channel(stream, chan);
 601                 if (ret < 0)
 602                         goto err;
 603                 break;
 604         }
 605         default:
 606                 break;
 607         }
 608         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 609
 610         /* Performing lib ring buffer ioctl after our own. */
 611         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 612         if (ret < 0)
 613                 goto err;
 614
 615         switch (cmd) {
 616         case RING_BUFFER_PUT_NEXT_SUBBUF:
 617         {
 618                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 619                                 cmd, arg);
 620                 break;
 621         }
 622         default:
 623                 break;
 624         }
 625 err:
 626         return ret;
 627 }
 628
 629 #ifdef CONFIG_COMPAT
 630 static
 631 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 632                 unsigned int cmd, unsigned long arg)
 633 {
 634         int ret;
 635         struct lttng_metadata_stream *stream = filp->private_data;
 636         struct lib_ring_buffer *buf = stream->priv;
 637
 638         switch (cmd) {
 639         case RING_BUFFER_GET_NEXT_SUBBUF:
 640         {
 641                 struct lttng_metadata_stream *stream = filp->private_data;
 642                 struct lib_ring_buffer *buf = stream->priv;
 643                 struct channel *chan = buf->backend.chan;
 644
 645                 ret = lttng_metadata_output_channel(stream, chan);
 646                 if (ret > 0) {
 647                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 648                         ret = 0;
 649                 } else if (ret < 0)
 650                         goto err;
 651                 break;
 652         }
 653         case RING_BUFFER_GET_SUBBUF:
 654         {
 655                 /*
 656                  * Random access is not allowed for metadata channel.
 657                  */
 658                 return -ENOSYS;
 659         }
 660         default:
 661                 break;
 662         }
 663         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 664
 665         /* Performing lib ring buffer ioctl after our own. */
 666         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 667         if (ret < 0)
 668                 goto err;
 669
 670         switch (cmd) {
 671         case RING_BUFFER_PUT_NEXT_SUBBUF:
 672         {
 673                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 674                                 cmd, arg);
 675                 break;
 676         }
 677         default:
 678                 break;
 679         }
 680 err:
 681         return ret;
 682 }
 683 #endif
 684
 685 /*
 686  * This is not used by anonymous file descriptors. This code is left
 687  * there if we ever want to implement an inode with open() operation.
 688  */
 689 static
 690 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 691 {
 692         struct lttng_metadata_stream *stream = inode->i_private;
 693         struct lib_ring_buffer *buf = stream->priv;
 694
 695         file->private_data = buf;
 696         /*
 697          * Since life-time of metadata cache differs from that of
 698          * session, we need to keep our own reference on the transport.
 699          */
 700         if (!try_module_get(stream->transport->owner)) {
 701                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 702                 return -EBUSY;
 703         }
 704         return lib_ring_buffer_open(inode, file, buf);
 705 }
 706
 707 static
 708 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 709 {
 710         struct lttng_metadata_stream *stream = file->private_data;
 711         struct lib_ring_buffer *buf = stream->priv;
 712
 713         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 714         module_put(stream->transport->owner);
 715         return lib_ring_buffer_release(inode, file, buf);
 716 }
 717
 718 static
 719 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 720                 struct pipe_inode_info *pipe, size_t len,
 721                 unsigned int flags)
 722 {
 723         struct lttng_metadata_stream *stream = in->private_data;
 724         struct lib_ring_buffer *buf = stream->priv;
 725
 726         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 727                         flags, buf);
 728 }
 729
 730 static
 731 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 732                 struct vm_area_struct *vma)
 733 {
 734         struct lttng_metadata_stream *stream = filp->private_data;
 735         struct lib_ring_buffer *buf = stream->priv;
 736
 737         return lib_ring_buffer_mmap(filp, vma, buf);
 738 }
 739
 740 static
 741 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 742         .owner = THIS_MODULE,
 743         .open = lttng_metadata_ring_buffer_open,
 744         .release = lttng_metadata_ring_buffer_release,
 745         .poll = lttng_metadata_ring_buffer_poll,
 746         .splice_read = lttng_metadata_ring_buffer_splice_read,
 747         .mmap = lttng_metadata_ring_buffer_mmap,
 748         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 749         .llseek = vfs_lib_ring_buffer_no_llseek,
 750 #ifdef CONFIG_COMPAT
 751         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 752 #endif
 753 };
 754
 755 static
 756 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 757                 const struct file_operations *fops)
 758 {
 759         int stream_fd, ret;
 760         struct file *stream_file;
 761
 762         stream_fd = get_unused_fd();
 763         if (stream_fd < 0) {
 764                 ret = stream_fd;
 765                 goto fd_error;
 766         }
 767         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 768                         stream_priv, O_RDWR);
 769         if (IS_ERR(stream_file)) {
 770                 ret = PTR_ERR(stream_file);
 771                 goto file_error;
 772         }
 773         /*
 774          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 775          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 776          * file descriptor, so we set FMODE_PREAD here.
 777          */
 778         stream_file->f_mode |= FMODE_PREAD;
 779         fd_install(stream_fd, stream_file);
 780         /*
 781          * The stream holds a reference to the channel within the generic ring
 782          * buffer library, so no need to hold a refcount on the channel and
 783          * session files here.
 784          */
 785         return stream_fd;
 786
 787 file_error:
 788         put_unused_fd(stream_fd);
 789 fd_error:
 790         return ret;
 791 }
 792
 793 static
 794 int lttng_abi_open_stream(struct file *channel_file)
 795 {
 796         struct lttng_channel *channel = channel_file->private_data;
 797         struct lib_ring_buffer *buf;
 798         int ret;
 799         void *stream_priv;
 800
 801         buf = channel->ops->buffer_read_open(channel->chan);
 802         if (!buf)
 803                 return -ENOENT;
 804
 805         stream_priv = buf;
 806         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 807                         &lttng_stream_ring_buffer_file_operations);
 808         if (ret < 0)
 809                 goto fd_error;
 810
 811         return ret;
 812
 813 fd_error:
 814         channel->ops->buffer_read_close(buf);
 815         return ret;
 816 }
 817
 818 static
 819 int lttng_abi_open_metadata_stream(struct file *channel_file)
 820 {
 821         struct lttng_channel *channel = channel_file->private_data;
 822         struct lttng_session *session = channel->session;
 823         struct lib_ring_buffer *buf;
 824         int ret;
 825         struct lttng_metadata_stream *metadata_stream;
 826         void *stream_priv;
 827
 828         buf = channel->ops->buffer_read_open(channel->chan);
 829         if (!buf)
 830                 return -ENOENT;
 831
 832         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 833                         GFP_KERNEL);
 834         if (!metadata_stream) {
 835                 ret = -ENOMEM;
 836                 goto nomem;
 837         }
 838         metadata_stream->metadata_cache = session->metadata_cache;
 839         init_waitqueue_head(&metadata_stream->read_wait);
 840         metadata_stream->priv = buf;
 841         stream_priv = metadata_stream;
 842         metadata_stream->transport = channel->transport;
 843
 844         /*
 845          * Since life-time of metadata cache differs from that of
 846          * session, we need to keep our own reference on the transport.
 847          */
 848         if (!try_module_get(metadata_stream->transport->owner)) {
 849                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 850                 ret = -EINVAL;
 851                 goto notransport;
 852         }
 853
 854         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 855                         &lttng_metadata_ring_buffer_file_operations);
 856         if (ret < 0)
 857                 goto fd_error;
 858
 859         kref_get(&session->metadata_cache->refcount);
 860         list_add(&metadata_stream->list,
 861                 &session->metadata_cache->metadata_stream);
 862         return ret;
 863
 864 fd_error:
 865         module_put(metadata_stream->transport->owner);
 866 notransport:
 867         kfree(metadata_stream);
 868 nomem:
 869         channel->ops->buffer_read_close(buf);
 870         return ret;
 871 }
 872
 873 static
 874 int lttng_abi_create_event(struct file *channel_file,
 875                            struct lttng_kernel_event *event_param)
 876 {
 877         struct lttng_channel *channel = channel_file->private_data;
 878         struct lttng_event *event;
 879         int event_fd, ret;
 880         struct file *event_file;
 881
 882         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 883         switch (event_param->instrumentation) {
 884         case LTTNG_KERNEL_KRETPROBE:
 885                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 886                 break;
 887         case LTTNG_KERNEL_KPROBE:
 888                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 889                 break;
 890         case LTTNG_KERNEL_FUNCTION:
 891                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 892                 break;
 893         default:
 894                 break;
 895         }
 896         switch (event_param->instrumentation) {
 897         default:
 898                 event_fd = get_unused_fd();
 899                 if (event_fd < 0) {
 900                         ret = event_fd;
 901                         goto fd_error;
 902                 }
 903                 event_file = anon_inode_getfile("[lttng_event]",
 904                                                 &lttng_event_fops,
 905                                                 NULL, O_RDWR);
 906                 if (IS_ERR(event_file)) {
 907                         ret = PTR_ERR(event_file);
 908                         goto file_error;
 909                 }
 910                 /*
 911                  * We tolerate no failure path after event creation. It
 912                  * will stay invariant for the rest of the session.
 913                  */
 914                 event = lttng_event_create(channel, event_param, NULL, NULL);
 915                 if (!event) {
 916                         ret = -EINVAL;
 917                         goto event_error;
 918                 }
 919                 event_file->private_data = event;
 920                 fd_install(event_fd, event_file);
 921                 /* The event holds a reference on the channel */
 922                 atomic_long_inc(&channel_file->f_count);
 923                 break;
 924         case LTTNG_KERNEL_SYSCALL:
 925                 /*
 926                  * Only all-syscall tracing supported for now.
 927                  */
 928                 if (event_param->name[0] != '\0')
 929                         return -EINVAL;
 930                 ret = lttng_syscalls_register(channel, NULL);
 931                 if (ret)
 932                         goto fd_error;
 933                 event_fd = 0;
 934                 break;
 935         }
 936         return event_fd;
 937
 938 event_error:
 939         fput(event_file);
 940 file_error:
 941         put_unused_fd(event_fd);
 942 fd_error:
 943         return ret;
 944 }
 945
 946 /**
 947  *      lttng_channel_ioctl - lttng syscall through ioctl
 948  *
 949  *      @file: the file
 950  *      @cmd: the command
 951  *      @arg: command arg
 952  *
 953  *      This ioctl implements lttng commands:
 954  *      LTTNG_KERNEL_STREAM
 955  *              Returns an event stream file descriptor or failure.
 956  *              (typically, one event stream records events from one CPU)
 957  *      LTTNG_KERNEL_EVENT
 958  *              Returns an event file descriptor or failure.
 959  *      LTTNG_KERNEL_CONTEXT
 960  *              Prepend a context field to each event in the channel
 961  *      LTTNG_KERNEL_ENABLE
 962  *              Enable recording for events in this channel (weak enable)
 963  *      LTTNG_KERNEL_DISABLE
 964  *              Disable recording for events in this channel (strong disable)
 965  *
 966  * Channel and event file descriptors also hold a reference on the session.
 967  */
 968 static
 969 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 970 {
 971         struct lttng_channel *channel = file->private_data;
 972
 973         switch (cmd) {
 974         case LTTNG_KERNEL_OLD_STREAM:
 975         case LTTNG_KERNEL_STREAM:
 976                 return lttng_abi_open_stream(file);
 977         case LTTNG_KERNEL_OLD_EVENT:
 978         {
 979                 struct lttng_kernel_event *uevent_param;
 980                 struct lttng_kernel_old_event *old_uevent_param;
 981                 int ret;
 982
 983                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
 984                                 GFP_KERNEL);
 985                 if (!uevent_param) {
 986                         ret = -ENOMEM;
 987                         goto old_event_end;
 988                 }
 989                 old_uevent_param = kmalloc(
 990                                 sizeof(struct lttng_kernel_old_event),
 991                                 GFP_KERNEL);
 992                 if (!old_uevent_param) {
 993                         ret = -ENOMEM;
 994                         goto old_event_error_free_param;
 995                 }
 996                 if (copy_from_user(old_uevent_param,
 997                                 (struct lttng_kernel_old_event __user *) arg,
 998                                 sizeof(struct lttng_kernel_old_event))) {
 999                         ret = -EFAULT;
1000                         goto old_event_error_free_old_param;
1001                 }
1002
1003                 memcpy(uevent_param->name, old_uevent_param->name,
1004                                 sizeof(uevent_param->name));
1005                 uevent_param->instrumentation =
1006                         old_uevent_param->instrumentation;
1007
1008                 switch (old_uevent_param->instrumentation) {
1009                 case LTTNG_KERNEL_KPROBE:
1010                         uevent_param->u.kprobe.addr =
1011                                 old_uevent_param->u.kprobe.addr;
1012                         uevent_param->u.kprobe.offset =
1013                                 old_uevent_param->u.kprobe.offset;
1014                         memcpy(uevent_param->u.kprobe.symbol_name,
1015                                 old_uevent_param->u.kprobe.symbol_name,
1016                                 sizeof(uevent_param->u.kprobe.symbol_name));
1017                         break;
1018                 case LTTNG_KERNEL_KRETPROBE:
1019                         uevent_param->u.kretprobe.addr =
1020                                 old_uevent_param->u.kretprobe.addr;
1021                         uevent_param->u.kretprobe.offset =
1022                                 old_uevent_param->u.kretprobe.offset;
1023                         memcpy(uevent_param->u.kretprobe.symbol_name,
1024                                 old_uevent_param->u.kretprobe.symbol_name,
1025                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1026                         break;
1027                 case LTTNG_KERNEL_FUNCTION:
1028                         memcpy(uevent_param->u.ftrace.symbol_name,
1029                                         old_uevent_param->u.ftrace.symbol_name,
1030                                         sizeof(uevent_param->u.ftrace.symbol_name));
1031                         break;
1032                 default:
1033                         break;
1034                 }
1035                 ret = lttng_abi_create_event(file, uevent_param);
1036
1037 old_event_error_free_old_param:
1038                 kfree(old_uevent_param);
1039 old_event_error_free_param:
1040                 kfree(uevent_param);
1041 old_event_end:
1042                 return ret;
1043         }
1044         case LTTNG_KERNEL_EVENT:
1045         {
1046                 struct lttng_kernel_event uevent_param;
1047
1048                 if (copy_from_user(&uevent_param,
1049                                 (struct lttng_kernel_event __user *) arg,
1050                                 sizeof(uevent_param)))
1051                         return -EFAULT;
1052                 return lttng_abi_create_event(file, &uevent_param);
1053         }
1054         case LTTNG_KERNEL_OLD_CONTEXT:
1055         {
1056                 struct lttng_kernel_context *ucontext_param;
1057                 struct lttng_kernel_old_context *old_ucontext_param;
1058                 int ret;
1059
1060                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1061                                 GFP_KERNEL);
1062                 if (!ucontext_param) {
1063                         ret = -ENOMEM;
1064                         goto old_ctx_end;
1065                 }
1066                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1067                                 GFP_KERNEL);
1068                 if (!old_ucontext_param) {
1069                         ret = -ENOMEM;
1070                         goto old_ctx_error_free_param;
1071                 }
1072
1073                 if (copy_from_user(old_ucontext_param,
1074                                 (struct lttng_kernel_old_context __user *) arg,
1075                                 sizeof(struct lttng_kernel_old_context))) {
1076                         ret = -EFAULT;
1077                         goto old_ctx_error_free_old_param;
1078                 }
1079                 ucontext_param->ctx = old_ucontext_param->ctx;
1080                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1081                                 sizeof(ucontext_param->padding));
1082                 /* only type that uses the union */
1083                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1084                         ucontext_param->u.perf_counter.type =
1085                                 old_ucontext_param->u.perf_counter.type;
1086                         ucontext_param->u.perf_counter.config =
1087                                 old_ucontext_param->u.perf_counter.config;
1088                         memcpy(ucontext_param->u.perf_counter.name,
1089                                 old_ucontext_param->u.perf_counter.name,
1090                                 sizeof(ucontext_param->u.perf_counter.name));
1091                 }
1092
1093                 ret = lttng_abi_add_context(file,
1094                                 ucontext_param,
1095                                 &channel->ctx, channel->session);
1096
1097 old_ctx_error_free_old_param:
1098                 kfree(old_ucontext_param);
1099 old_ctx_error_free_param:
1100                 kfree(ucontext_param);
1101 old_ctx_end:
1102                 return ret;
1103         }
1104         case LTTNG_KERNEL_CONTEXT:
1105         {
1106                 struct lttng_kernel_context ucontext_param;
1107
1108                 if (copy_from_user(&ucontext_param,
1109                                 (struct lttng_kernel_context __user *) arg,
1110                                 sizeof(ucontext_param)))
1111                         return -EFAULT;
1112                 return lttng_abi_add_context(file,
1113                                 &ucontext_param,
1114                                 &channel->ctx, channel->session);
1115         }
1116         case LTTNG_KERNEL_OLD_ENABLE:
1117         case LTTNG_KERNEL_ENABLE:
1118                 return lttng_channel_enable(channel);
1119         case LTTNG_KERNEL_OLD_DISABLE:
1120         case LTTNG_KERNEL_DISABLE:
1121                 return lttng_channel_disable(channel);
1122         default:
1123                 return -ENOIOCTLCMD;
1124         }
1125
1126 }
1127
1128 /**
1129  *      lttng_metadata_ioctl - lttng syscall through ioctl
1130  *
1131  *      @file: the file
1132  *      @cmd: the command
1133  *      @arg: command arg
1134  *
1135  *      This ioctl implements lttng commands:
1136  *      LTTNG_KERNEL_STREAM
1137  *              Returns an event stream file descriptor or failure.
1138  *
1139  * Channel and event file descriptors also hold a reference on the session.
1140  */
1141 static
1142 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1143 {
1144         switch (cmd) {
1145         case LTTNG_KERNEL_OLD_STREAM:
1146         case LTTNG_KERNEL_STREAM:
1147                 return lttng_abi_open_metadata_stream(file);
1148         default:
1149                 return -ENOIOCTLCMD;
1150         }
1151 }
1152
1153 /**
1154  *      lttng_channel_poll - lttng stream addition/removal monitoring
1155  *
1156  *      @file: the file
1157  *      @wait: poll table
1158  */
1159 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1160 {
1161         struct lttng_channel *channel = file->private_data;
1162         unsigned int mask = 0;
1163
1164         if (file->f_mode & FMODE_READ) {
1165                 poll_wait_set_exclusive(wait);
1166                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1167                           wait);
1168
1169                 if (channel->ops->is_disabled(channel->chan))
1170                         return POLLERR;
1171                 if (channel->ops->is_finalized(channel->chan))
1172                         return POLLHUP;
1173                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1174                         return POLLIN | POLLRDNORM;
1175                 return 0;
1176         }
1177         return mask;
1178
1179 }
1180
1181 static
1182 int lttng_channel_release(struct inode *inode, struct file *file)
1183 {
1184         struct lttng_channel *channel = file->private_data;
1185
1186         if (channel)
1187                 fput(channel->session->file);
1188         return 0;
1189 }
1190
1191 static
1192 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1193 {
1194         struct lttng_channel *channel = file->private_data;
1195
1196         if (channel) {
1197                 lttng_metadata_channel_destroy(channel);
1198                 fput(channel->session->file);
1199         }
1200
1201         return 0;
1202 }
1203
1204 static const struct file_operations lttng_channel_fops = {
1205         .owner = THIS_MODULE,
1206         .release = lttng_channel_release,
1207         .poll = lttng_channel_poll,
1208         .unlocked_ioctl = lttng_channel_ioctl,
1209 #ifdef CONFIG_COMPAT
1210         .compat_ioctl = lttng_channel_ioctl,
1211 #endif
1212 };
1213
1214 static const struct file_operations lttng_metadata_fops = {
1215         .owner = THIS_MODULE,
1216         .release = lttng_metadata_channel_release,
1217         .unlocked_ioctl = lttng_metadata_ioctl,
1218 #ifdef CONFIG_COMPAT
1219         .compat_ioctl = lttng_metadata_ioctl,
1220 #endif
1221 };
1222
1223 /**
1224  *      lttng_event_ioctl - lttng syscall through ioctl
1225  *
1226  *      @file: the file
1227  *      @cmd: the command
1228  *      @arg: command arg
1229  *
1230  *      This ioctl implements lttng commands:
1231  *      LTTNG_KERNEL_CONTEXT
1232  *              Prepend a context field to each record of this event
1233  *      LTTNG_KERNEL_ENABLE
1234  *              Enable recording for this event (weak enable)
1235  *      LTTNG_KERNEL_DISABLE
1236  *              Disable recording for this event (strong disable)
1237  */
1238 static
1239 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1240 {
1241         struct lttng_event *event = file->private_data;
1242
1243         switch (cmd) {
1244         case LTTNG_KERNEL_OLD_CONTEXT:
1245         {
1246                 struct lttng_kernel_context *ucontext_param;
1247                 struct lttng_kernel_old_context *old_ucontext_param;
1248                 int ret;
1249
1250                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1251                                 GFP_KERNEL);
1252                 if (!ucontext_param) {
1253                         ret = -ENOMEM;
1254                         goto old_ctx_end;
1255                 }
1256                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1257                                 GFP_KERNEL);
1258                 if (!old_ucontext_param) {
1259                         ret = -ENOMEM;
1260                         goto old_ctx_error_free_param;
1261                 }
1262
1263                 if (copy_from_user(old_ucontext_param,
1264                                         (struct lttng_kernel_old_context __user *) arg,
1265                                         sizeof(struct lttng_kernel_old_context))) {
1266                         ret = -EFAULT;
1267                         goto old_ctx_error_free_old_param;
1268                 }
1269                 ucontext_param->ctx = old_ucontext_param->ctx;
1270                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1271                                 sizeof(ucontext_param->padding));
1272                 /* only type that uses the union */
1273                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1274                         ucontext_param->u.perf_counter.type =
1275                                 old_ucontext_param->u.perf_counter.type;
1276                         ucontext_param->u.perf_counter.config =
1277                                 old_ucontext_param->u.perf_counter.config;
1278                         memcpy(ucontext_param->u.perf_counter.name,
1279                                         old_ucontext_param->u.perf_counter.name,
1280                                         sizeof(ucontext_param->u.perf_counter.name));
1281                 }
1282
1283                 ret = lttng_abi_add_context(file,
1284                                 ucontext_param,
1285                                 &event->ctx, event->chan->session);
1286
1287 old_ctx_error_free_old_param:
1288                 kfree(old_ucontext_param);
1289 old_ctx_error_free_param:
1290                 kfree(ucontext_param);
1291 old_ctx_end:
1292                 return ret;
1293         }
1294         case LTTNG_KERNEL_CONTEXT:
1295         {
1296                 struct lttng_kernel_context ucontext_param;
1297
1298                 if (copy_from_user(&ucontext_param,
1299                                         (struct lttng_kernel_context __user *) arg,
1300                                         sizeof(ucontext_param)))
1301                         return -EFAULT;
1302                 return lttng_abi_add_context(file,
1303                                 &ucontext_param,
1304                                 &event->ctx, event->chan->session);
1305         }
1306         case LTTNG_KERNEL_OLD_ENABLE:
1307         case LTTNG_KERNEL_ENABLE:
1308                 return lttng_event_enable(event);
1309         case LTTNG_KERNEL_OLD_DISABLE:
1310         case LTTNG_KERNEL_DISABLE:
1311                 return lttng_event_disable(event);
1312         default:
1313                 return -ENOIOCTLCMD;
1314         }
1315 }
1316
1317 static
1318 int lttng_event_release(struct inode *inode, struct file *file)
1319 {
1320         struct lttng_event *event = file->private_data;
1321
1322         if (event)
1323                 fput(event->chan->file);
1324         return 0;
1325 }
1326
1327 /* TODO: filter control ioctl */
1328 static const struct file_operations lttng_event_fops = {
1329         .owner = THIS_MODULE,
1330         .release = lttng_event_release,
1331         .unlocked_ioctl = lttng_event_ioctl,
1332 #ifdef CONFIG_COMPAT
1333         .compat_ioctl = lttng_event_ioctl,
1334 #endif
1335 };
1336
1337 static int put_u64(uint64_t val, unsigned long arg)
1338 {
1339         return put_user(val, (uint64_t __user *) arg);
1340 }
1341
1342 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1343                 unsigned int cmd, unsigned long arg)
1344 {
1345         struct lib_ring_buffer *buf = filp->private_data;
1346         struct channel *chan = buf->backend.chan;
1347         const struct lib_ring_buffer_config *config = &chan->backend.config;
1348         struct lttng_channel *lttng_chan = channel_get_private(chan);
1349         int ret;
1350
1351         if (atomic_read(&chan->record_disabled))
1352                 return -EIO;
1353
1354         switch (cmd) {
1355         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1356         {
1357                 uint64_t ts;
1358
1359                 if (!lttng_chan->ops)
1360                         goto error;
1361                 ret = lttng_chan->ops->timestamp_begin(config, buf, &ts);
1362                 if (ret < 0)
1363                         goto error;
1364                 return put_u64(ts, arg);
1365         }
1366         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1367         {
1368                 uint64_t ts;
1369
1370                 if (!lttng_chan->ops)
1371                         goto error;
1372                 ret = lttng_chan->ops->timestamp_end(config, buf, &ts);
1373                 if (ret < 0)
1374                         goto error;
1375                 return put_u64(ts, arg);
1376         }
1377         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1378         {
1379                 uint64_t ed;
1380
1381                 if (!lttng_chan->ops)
1382                         goto error;
1383                 ret = lttng_chan->ops->events_discarded(config, buf, &ed);
1384                 if (ret < 0)
1385                         goto error;
1386                 return put_u64(ed, arg);
1387         }
1388         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1389         {
1390                 uint64_t cs;
1391
1392                 if (!lttng_chan->ops)
1393                         goto error;
1394                 ret = lttng_chan->ops->content_size(config, buf, &cs);
1395                 if (ret < 0)
1396                         goto error;
1397                 return put_u64(cs, arg);
1398         }
1399         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1400         {
1401                 uint64_t ps;
1402
1403                 if (!lttng_chan->ops)
1404                         goto error;
1405                 ret = lttng_chan->ops->packet_size(config, buf, &ps);
1406                 if (ret < 0)
1407                         goto error;
1408                 return put_u64(ps, arg);
1409         }
1410         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1411         {
1412                 uint64_t si;
1413
1414                 if (!lttng_chan->ops)
1415                         goto error;
1416                 ret = lttng_chan->ops->stream_id(config, buf, &si);
1417                 if (ret < 0)
1418                         goto error;
1419                 return put_u64(si, arg);
1420         }
1421         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1422         {
1423                 uint64_t ts;
1424
1425                 if (!lttng_chan->ops)
1426                         goto error;
1427                 ret = lttng_chan->ops->current_timestamp(config, buf, &ts);
1428                 if (ret < 0)
1429                         goto error;
1430                 return put_u64(ts, arg);
1431         }
1432         default:
1433                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1434                                 cmd, arg);
1435         }
1436
1437 error:
1438         return -ENOSYS;
1439 }
1440
1441 #ifdef CONFIG_COMPAT
1442 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1443                 unsigned int cmd, unsigned long arg)
1444 {
1445         struct lib_ring_buffer *buf = filp->private_data;
1446         struct channel *chan = buf->backend.chan;
1447         const struct lib_ring_buffer_config *config = &chan->backend.config;
1448         struct lttng_channel *lttng_chan = channel_get_private(chan);
1449         int ret;
1450
1451         if (atomic_read(&chan->record_disabled))
1452                 return -EIO;
1453
1454         switch (cmd) {
1455         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1456         {
1457                 uint64_t ts;
1458
1459                 if (!lttng_chan->ops)
1460                         goto error;
1461                 ret = lttng_chan->ops->timestamp_begin(config, buf, &ts);
1462                 if (ret < 0)
1463                         goto error;
1464                 return put_u64(ts, arg);
1465         }
1466         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1467         {
1468                 uint64_t ts;
1469
1470                 if (!lttng_chan->ops)
1471                         goto error;
1472                 ret = lttng_chan->ops->timestamp_end(config, buf, &ts);
1473                 if (ret < 0)
1474                         goto error;
1475                 return put_u64(ts, arg);
1476         }
1477         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1478         {
1479                 uint64_t ed;
1480
1481                 if (!lttng_chan->ops)
1482                         goto error;
1483                 ret = lttng_chan->ops->events_discarded(config, buf, &ed);
1484                 if (ret < 0)
1485                         goto error;
1486                 return put_u64(ed, arg);
1487         }
1488         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1489         {
1490                 uint64_t cs;
1491
1492                 if (!lttng_chan->ops)
1493                         goto error;
1494                 ret = lttng_chan->ops->content_size(config, buf, &cs);
1495                 if (ret < 0)
1496                         goto error;
1497                 return put_u64(cs, arg);
1498         }
1499         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1500         {
1501                 uint64_t ps;
1502
1503                 if (!lttng_chan->ops)
1504                         goto error;
1505                 ret = lttng_chan->ops->packet_size(config, buf, &ps);
1506                 if (ret < 0)
1507                         goto error;
1508                 return put_u64(ps, arg);
1509         }
1510         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1511         {
1512                 uint64_t si;
1513
1514                 if (!lttng_chan->ops)
1515                         goto error;
1516                 ret = lttng_chan->ops->stream_id(config, buf, &si);
1517                 if (ret < 0)
1518                         goto error;
1519                 return put_u64(si, arg);
1520         }
1521         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1522         {
1523                 uint64_t ts;
1524
1525                 if (!lttng_chan->ops)
1526                         goto error;
1527                 ret = lttng_chan->ops->current_timestamp(config, buf, &ts);
1528                 if (ret < 0)
1529                         goto error;
1530                 return put_u64(ts, arg);
1531         }
1532         default:
1533                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1534                                 cmd, arg);
1535         }
1536
1537 error:
1538         return -ENOSYS;
1539 }
1540 #endif /* CONFIG_COMPAT */
1541
1542 static void lttng_stream_override_ring_buffer_fops(void)
1543 {
1544         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1545         lttng_stream_ring_buffer_file_operations.open =
1546                 lib_ring_buffer_file_operations.open;
1547         lttng_stream_ring_buffer_file_operations.release =
1548                 lib_ring_buffer_file_operations.release;
1549         lttng_stream_ring_buffer_file_operations.poll =
1550                 lib_ring_buffer_file_operations.poll;
1551         lttng_stream_ring_buffer_file_operations.splice_read =
1552                 lib_ring_buffer_file_operations.splice_read;
1553         lttng_stream_ring_buffer_file_operations.mmap =
1554                 lib_ring_buffer_file_operations.mmap;
1555         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1556                 lttng_stream_ring_buffer_ioctl;
1557         lttng_stream_ring_buffer_file_operations.llseek =
1558                 lib_ring_buffer_file_operations.llseek;
1559 #ifdef CONFIG_COMPAT
1560         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1561                 lttng_stream_ring_buffer_compat_ioctl;
1562 #endif
1563 }
1564
1565 int __init lttng_abi_init(void)
1566 {
1567         int ret = 0;
1568
1569         wrapper_vmalloc_sync_all();
1570         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1571                                         &lttng_fops, NULL);
1572
1573         if (!lttng_proc_dentry) {
1574                 printk(KERN_ERR "Error creating LTTng control file\n");
1575                 ret = -ENOMEM;
1576                 goto error;
1577         }
1578         lttng_stream_override_ring_buffer_fops();
1579
1580 error:
1581         return ret;
1582 }
1583
1584 void __exit lttng_abi_exit(void)
1585 {
1586         if (lttng_proc_dentry)
1587                 remove_proc_entry("lttng", NULL);
1588 }