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 #include "lib/ringbuffer/frontend_types.h"
  57
  58 /*
  59  * This is LTTng's own personal way to create a system call as an external
  60  * module. We use ioctl() on /proc/lttng.
  61  */
  62
  63 static struct proc_dir_entry *lttng_proc_dentry;
  64 static const struct file_operations lttng_fops;
  65 static const struct file_operations lttng_session_fops;
  66 static const struct file_operations lttng_channel_fops;
  67 static const struct file_operations lttng_metadata_fops;
  68 static const struct file_operations lttng_event_fops;
  69 static struct file_operations lttng_stream_ring_buffer_file_operations;
  70
  71 /*
  72  * Teardown management: opened file descriptors keep a refcount on the module,
  73  * so it can only exit when all file descriptors are closed.
  74  */
  75
  76 static
  77 int lttng_abi_create_session(void)
  78 {
  79         struct lttng_session *session;
  80         struct file *session_file;
  81         int session_fd, ret;
  82
  83         session = lttng_session_create();
  84         if (!session)
  85                 return -ENOMEM;
  86         session_fd = get_unused_fd();
  87         if (session_fd < 0) {
  88                 ret = session_fd;
  89                 goto fd_error;
  90         }
  91         session_file = anon_inode_getfile("[lttng_session]",
  92                                           &lttng_session_fops,
  93                                           session, O_RDWR);
  94         if (IS_ERR(session_file)) {
  95                 ret = PTR_ERR(session_file);
  96                 goto file_error;
  97         }
  98         session->file = session_file;
  99         fd_install(session_fd, session_file);
 100         return session_fd;
 101
 102 file_error:
 103         put_unused_fd(session_fd);
 104 fd_error:
 105         lttng_session_destroy(session);
 106         return ret;
 107 }
 108
 109 static
 110 int lttng_abi_tracepoint_list(void)
 111 {
 112         struct file *tracepoint_list_file;
 113         int file_fd, ret;
 114
 115         file_fd = get_unused_fd();
 116         if (file_fd < 0) {
 117                 ret = file_fd;
 118                 goto fd_error;
 119         }
 120
 121         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 122                                           &lttng_tracepoint_list_fops,
 123                                           NULL, O_RDWR);
 124         if (IS_ERR(tracepoint_list_file)) {
 125                 ret = PTR_ERR(tracepoint_list_file);
 126                 goto file_error;
 127         }
 128         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 129         if (ret < 0)
 130                 goto open_error;
 131         fd_install(file_fd, tracepoint_list_file);
 132         if (file_fd < 0) {
 133                 ret = file_fd;
 134                 goto fd_error;
 135         }
 136         return file_fd;
 137
 138 open_error:
 139         fput(tracepoint_list_file);
 140 file_error:
 141         put_unused_fd(file_fd);
 142 fd_error:
 143         return ret;
 144 }
 145
 146 static
 147 int lttng_abi_syscall_list(void)
 148 {
 149         struct file *syscall_list_file;
 150         int file_fd, ret;
 151
 152         file_fd = get_unused_fd();
 153         if (file_fd < 0) {
 154                 ret = file_fd;
 155                 goto fd_error;
 156         }
 157
 158         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 159                                           &lttng_syscall_list_fops,
 160                                           NULL, O_RDWR);
 161         if (IS_ERR(syscall_list_file)) {
 162                 ret = PTR_ERR(syscall_list_file);
 163                 goto file_error;
 164         }
 165         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 166         if (ret < 0)
 167                 goto open_error;
 168         fd_install(file_fd, syscall_list_file);
 169         if (file_fd < 0) {
 170                 ret = file_fd;
 171                 goto fd_error;
 172         }
 173         return file_fd;
 174
 175 open_error:
 176         fput(syscall_list_file);
 177 file_error:
 178         put_unused_fd(file_fd);
 179 fd_error:
 180         return ret;
 181 }
 182
 183 static
 184 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 185 {
 186         v->major = LTTNG_MODULES_MAJOR_VERSION;
 187         v->minor = LTTNG_MODULES_MINOR_VERSION;
 188         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 189 }
 190
 191 static
 192 long lttng_abi_add_context(struct file *file,
 193         struct lttng_kernel_context *context_param,
 194         struct lttng_ctx **ctx, struct lttng_session *session)
 195 {
 196
 197         if (session->been_active)
 198                 return -EPERM;
 199
 200         switch (context_param->ctx) {
 201         case LTTNG_KERNEL_CONTEXT_PID:
 202                 return lttng_add_pid_to_ctx(ctx);
 203         case LTTNG_KERNEL_CONTEXT_PRIO:
 204                 return lttng_add_prio_to_ctx(ctx);
 205         case LTTNG_KERNEL_CONTEXT_NICE:
 206                 return lttng_add_nice_to_ctx(ctx);
 207         case LTTNG_KERNEL_CONTEXT_VPID:
 208                 return lttng_add_vpid_to_ctx(ctx);
 209         case LTTNG_KERNEL_CONTEXT_TID:
 210                 return lttng_add_tid_to_ctx(ctx);
 211         case LTTNG_KERNEL_CONTEXT_VTID:
 212                 return lttng_add_vtid_to_ctx(ctx);
 213         case LTTNG_KERNEL_CONTEXT_PPID:
 214                 return lttng_add_ppid_to_ctx(ctx);
 215         case LTTNG_KERNEL_CONTEXT_VPPID:
 216                 return lttng_add_vppid_to_ctx(ctx);
 217         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 218                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 219                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 220                                 context_param->u.perf_counter.config,
 221                                 context_param->u.perf_counter.name,
 222                                 ctx);
 223         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 224                 return lttng_add_procname_to_ctx(ctx);
 225         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 226                 return lttng_add_hostname_to_ctx(ctx);
 227         default:
 228                 return -EINVAL;
 229         }
 230 }
 231
 232 /**
 233  *      lttng_ioctl - lttng syscall through ioctl
 234  *
 235  *      @file: the file
 236  *      @cmd: the command
 237  *      @arg: command arg
 238  *
 239  *      This ioctl implements lttng commands:
 240  *      LTTNG_KERNEL_SESSION
 241  *              Returns a LTTng trace session file descriptor
 242  *      LTTNG_KERNEL_TRACER_VERSION
 243  *              Returns the LTTng kernel tracer version
 244  *      LTTNG_KERNEL_TRACEPOINT_LIST
 245  *              Returns a file descriptor listing available tracepoints
 246  *      LTTNG_KERNEL_WAIT_QUIESCENT
 247  *              Returns after all previously running probes have completed
 248  *
 249  * The returned session will be deleted when its file descriptor is closed.
 250  */
 251 static
 252 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 253 {
 254         switch (cmd) {
 255         case LTTNG_KERNEL_OLD_SESSION:
 256         case LTTNG_KERNEL_SESSION:
 257                 return lttng_abi_create_session();
 258         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 259         {
 260                 struct lttng_kernel_tracer_version v;
 261                 struct lttng_kernel_old_tracer_version oldv;
 262                 struct lttng_kernel_old_tracer_version *uversion =
 263                         (struct lttng_kernel_old_tracer_version __user *) arg;
 264
 265                 lttng_abi_tracer_version(&v);
 266                 oldv.major = v.major;
 267                 oldv.minor = v.minor;
 268                 oldv.patchlevel = v.patchlevel;
 269
 270                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 271                         return -EFAULT;
 272                 return 0;
 273         }
 274         case LTTNG_KERNEL_TRACER_VERSION:
 275         {
 276                 struct lttng_kernel_tracer_version version;
 277                 struct lttng_kernel_tracer_version *uversion =
 278                         (struct lttng_kernel_tracer_version __user *) arg;
 279
 280                 lttng_abi_tracer_version(&version);
 281
 282                 if (copy_to_user(uversion, &version, sizeof(version)))
 283                         return -EFAULT;
 284                 return 0;
 285         }
 286         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 287         case LTTNG_KERNEL_TRACEPOINT_LIST:
 288                 return lttng_abi_tracepoint_list();
 289         case LTTNG_KERNEL_SYSCALL_LIST:
 290                 return lttng_abi_syscall_list();
 291         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 292         case LTTNG_KERNEL_WAIT_QUIESCENT:
 293                 synchronize_trace();
 294                 return 0;
 295         case LTTNG_KERNEL_OLD_CALIBRATE:
 296         {
 297                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 298                         (struct lttng_kernel_old_calibrate __user *) arg;
 299                 struct lttng_kernel_old_calibrate old_calibrate;
 300                 struct lttng_kernel_calibrate calibrate;
 301                 int ret;
 302
 303                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 304                         return -EFAULT;
 305                 calibrate.type = old_calibrate.type;
 306                 ret = lttng_calibrate(&calibrate);
 307                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 308                         return -EFAULT;
 309                 return ret;
 310         }
 311         case LTTNG_KERNEL_CALIBRATE:
 312         {
 313                 struct lttng_kernel_calibrate __user *ucalibrate =
 314                         (struct lttng_kernel_calibrate __user *) arg;
 315                 struct lttng_kernel_calibrate calibrate;
 316                 int ret;
 317
 318                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 319                         return -EFAULT;
 320                 ret = lttng_calibrate(&calibrate);
 321                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 322                         return -EFAULT;
 323                 return ret;
 324         }
 325         default:
 326                 return -ENOIOCTLCMD;
 327         }
 328 }
 329
 330 static const struct file_operations lttng_fops = {
 331         .owner = THIS_MODULE,
 332         .unlocked_ioctl = lttng_ioctl,
 333 #ifdef CONFIG_COMPAT
 334         .compat_ioctl = lttng_ioctl,
 335 #endif
 336 };
 337
 338 static
 339 int lttng_abi_create_channel(struct file *session_file,
 340                              struct lttng_kernel_channel *chan_param,
 341                              enum channel_type channel_type)
 342 {
 343         struct lttng_session *session = session_file->private_data;
 344         const struct file_operations *fops = NULL;
 345         const char *transport_name;
 346         struct lttng_channel *chan;
 347         struct file *chan_file;
 348         int chan_fd;
 349         int ret = 0;
 350
 351         chan_fd = get_unused_fd();
 352         if (chan_fd < 0) {
 353                 ret = chan_fd;
 354                 goto fd_error;
 355         }
 356         switch (channel_type) {
 357         case PER_CPU_CHANNEL:
 358                 fops = &lttng_channel_fops;
 359                 break;
 360         case METADATA_CHANNEL:
 361                 fops = &lttng_metadata_fops;
 362                 break;
 363         }
 364
 365         chan_file = anon_inode_getfile("[lttng_channel]",
 366                                        fops,
 367                                        NULL, O_RDWR);
 368         if (IS_ERR(chan_file)) {
 369                 ret = PTR_ERR(chan_file);
 370                 goto file_error;
 371         }
 372         switch (channel_type) {
 373         case PER_CPU_CHANNEL:
 374                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 375                         transport_name = chan_param->overwrite ?
 376                                 "relay-overwrite" : "relay-discard";
 377                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 378                         transport_name = chan_param->overwrite ?
 379                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 380                 } else {
 381                         return -EINVAL;
 382                 }
 383                 break;
 384         case METADATA_CHANNEL:
 385                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 386                         transport_name = "relay-metadata";
 387                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 388                         transport_name = "relay-metadata-mmap";
 389                 else
 390                         return -EINVAL;
 391                 break;
 392         default:
 393                 transport_name = "<unknown>";
 394                 break;
 395         }
 396         /*
 397          * We tolerate no failure path after channel creation. It will stay
 398          * invariant for the rest of the session.
 399          */
 400         chan = lttng_channel_create(session, transport_name, NULL,
 401                                   chan_param->subbuf_size,
 402                                   chan_param->num_subbuf,
 403                                   chan_param->switch_timer_interval,
 404                                   chan_param->read_timer_interval,
 405                                   channel_type);
 406         if (!chan) {
 407                 ret = -EINVAL;
 408                 goto chan_error;
 409         }
 410         chan->file = chan_file;
 411         chan_file->private_data = chan;
 412         fd_install(chan_fd, chan_file);
 413         atomic_long_inc(&session_file->f_count);
 414
 415         return chan_fd;
 416
 417 chan_error:
 418         fput(chan_file);
 419 file_error:
 420         put_unused_fd(chan_fd);
 421 fd_error:
 422         return ret;
 423 }
 424
 425 /**
 426  *      lttng_session_ioctl - lttng session fd ioctl
 427  *
 428  *      @file: the file
 429  *      @cmd: the command
 430  *      @arg: command arg
 431  *
 432  *      This ioctl implements lttng commands:
 433  *      LTTNG_KERNEL_CHANNEL
 434  *              Returns a LTTng channel file descriptor
 435  *      LTTNG_KERNEL_ENABLE
 436  *              Enables tracing for a session (weak enable)
 437  *      LTTNG_KERNEL_DISABLE
 438  *              Disables tracing for a session (strong disable)
 439  *      LTTNG_KERNEL_METADATA
 440  *              Returns a LTTng metadata file descriptor
 441  *
 442  * The returned channel will be deleted when its file descriptor is closed.
 443  */
 444 static
 445 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 446 {
 447         struct lttng_session *session = file->private_data;
 448
 449         switch (cmd) {
 450         case LTTNG_KERNEL_OLD_CHANNEL:
 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                                 PER_CPU_CHANNEL);
 468         }
 469         case LTTNG_KERNEL_CHANNEL:
 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                                 PER_CPU_CHANNEL);
 479         }
 480         case LTTNG_KERNEL_OLD_SESSION_START:
 481         case LTTNG_KERNEL_OLD_ENABLE:
 482         case LTTNG_KERNEL_SESSION_START:
 483         case LTTNG_KERNEL_ENABLE:
 484                 return lttng_session_enable(session);
 485         case LTTNG_KERNEL_OLD_SESSION_STOP:
 486         case LTTNG_KERNEL_OLD_DISABLE:
 487         case LTTNG_KERNEL_SESSION_STOP:
 488         case LTTNG_KERNEL_DISABLE:
 489                 return lttng_session_disable(session);
 490         case LTTNG_KERNEL_OLD_METADATA:
 491         {
 492                 struct lttng_kernel_channel chan_param;
 493                 struct lttng_kernel_old_channel old_chan_param;
 494
 495                 if (copy_from_user(&old_chan_param,
 496                                 (struct lttng_kernel_old_channel __user *) arg,
 497                                 sizeof(struct lttng_kernel_old_channel)))
 498                         return -EFAULT;
 499                 chan_param.overwrite = old_chan_param.overwrite;
 500                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 501                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 502                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 503                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 504                 chan_param.output = old_chan_param.output;
 505
 506                 return lttng_abi_create_channel(file, &chan_param,
 507                                 METADATA_CHANNEL);
 508         }
 509         case LTTNG_KERNEL_METADATA:
 510         {
 511                 struct lttng_kernel_channel chan_param;
 512
 513                 if (copy_from_user(&chan_param,
 514                                         (struct lttng_kernel_channel __user *) arg,
 515                                         sizeof(struct lttng_kernel_channel)))
 516                         return -EFAULT;
 517                 return lttng_abi_create_channel(file, &chan_param,
 518                                 METADATA_CHANNEL);
 519         }
 520         default:
 521                 return -ENOIOCTLCMD;
 522         }
 523 }
 524
 525 /*
 526  * Called when the last file reference is dropped.
 527  *
 528  * Big fat note: channels and events are invariant for the whole session after
 529  * their creation. So this session destruction also destroys all channel and
 530  * event structures specific to this session (they are not destroyed when their
 531  * individual file is released).
 532  */
 533 static
 534 int lttng_session_release(struct inode *inode, struct file *file)
 535 {
 536         struct lttng_session *session = file->private_data;
 537
 538         if (session)
 539                 lttng_session_destroy(session);
 540         return 0;
 541 }
 542
 543 static const struct file_operations lttng_session_fops = {
 544         .owner = THIS_MODULE,
 545         .release = lttng_session_release,
 546         .unlocked_ioctl = lttng_session_ioctl,
 547 #ifdef CONFIG_COMPAT
 548         .compat_ioctl = lttng_session_ioctl,
 549 #endif
 550 };
 551
 552 /**
 553  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 554  *      @filp: the file
 555  *      @wait: poll table
 556  *
 557  *      Handles the poll operations for the metadata channels.
 558  */
 559 static
 560 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 561                 poll_table *wait)
 562 {
 563         struct lttng_metadata_stream *stream = filp->private_data;
 564         struct lib_ring_buffer *buf = stream->priv;
 565         int finalized;
 566         unsigned int mask = 0;
 567
 568         if (filp->f_mode & FMODE_READ) {
 569                 poll_wait_set_exclusive(wait);
 570                 poll_wait(filp, &stream->read_wait, wait);
 571
 572                 finalized = stream->finalized;
 573
 574                 /*
 575                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 576                  * ordering finalized load before offsets loads.
 577                  */
 578                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 579
 580                 if (finalized)
 581                         mask |= POLLHUP;
 582
 583                 if (stream->metadata_cache->metadata_written >
 584                                 stream->metadata_out)
 585                         mask |= POLLIN;
 586         }
 587
 588         return mask;
 589 }
 590
 591 static
 592 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 593                 unsigned int cmd, unsigned long arg)
 594 {
 595         struct lttng_metadata_stream *stream = filp->private_data;
 596
 597         stream->metadata_out = stream->metadata_in;
 598 }
 599
 600 static
 601 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 602                 unsigned int cmd, unsigned long arg)
 603 {
 604         int ret;
 605         struct lttng_metadata_stream *stream = filp->private_data;
 606         struct lib_ring_buffer *buf = stream->priv;
 607
 608         switch (cmd) {
 609         case RING_BUFFER_GET_NEXT_SUBBUF:
 610         {
 611                 struct lttng_metadata_stream *stream = filp->private_data;
 612                 struct lib_ring_buffer *buf = stream->priv;
 613                 struct channel *chan = buf->backend.chan;
 614
 615                 ret = lttng_metadata_output_channel(stream, chan);
 616                 if (ret > 0) {
 617                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 618                         ret = 0;
 619                 } else if (ret < 0)
 620                         goto err;
 621                 break;
 622         }
 623         case RING_BUFFER_GET_SUBBUF:
 624         {
 625                 /*
 626                  * Random access is not allowed for metadata channel.
 627                  */
 628                 return -ENOSYS;
 629         }
 630         case RING_BUFFER_FLUSH:
 631         {
 632                 struct lttng_metadata_stream *stream = filp->private_data;
 633                 struct lib_ring_buffer *buf = stream->priv;
 634                 struct channel *chan = buf->backend.chan;
 635
 636                 /*
 637                  * Before doing the actual ring buffer flush, write up to one
 638                  * packet of metadata in the ring buffer.
 639                  */
 640                 ret = lttng_metadata_output_channel(stream, chan);
 641                 if (ret < 0)
 642                         goto err;
 643                 break;
 644         }
 645         default:
 646                 break;
 647         }
 648         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 649
 650         /* Performing lib ring buffer ioctl after our own. */
 651         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 652         if (ret < 0)
 653                 goto err;
 654
 655         switch (cmd) {
 656         case RING_BUFFER_PUT_NEXT_SUBBUF:
 657         {
 658                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 659                                 cmd, arg);
 660                 break;
 661         }
 662         default:
 663                 break;
 664         }
 665 err:
 666         return ret;
 667 }
 668
 669 #ifdef CONFIG_COMPAT
 670 static
 671 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 672                 unsigned int cmd, unsigned long arg)
 673 {
 674         int ret;
 675         struct lttng_metadata_stream *stream = filp->private_data;
 676         struct lib_ring_buffer *buf = stream->priv;
 677
 678         switch (cmd) {
 679         case RING_BUFFER_GET_NEXT_SUBBUF:
 680         {
 681                 struct lttng_metadata_stream *stream = filp->private_data;
 682                 struct lib_ring_buffer *buf = stream->priv;
 683                 struct channel *chan = buf->backend.chan;
 684
 685                 ret = lttng_metadata_output_channel(stream, chan);
 686                 if (ret > 0) {
 687                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 688                         ret = 0;
 689                 } else if (ret < 0)
 690                         goto err;
 691                 break;
 692         }
 693         case RING_BUFFER_GET_SUBBUF:
 694         {
 695                 /*
 696                  * Random access is not allowed for metadata channel.
 697                  */
 698                 return -ENOSYS;
 699         }
 700         default:
 701                 break;
 702         }
 703         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 704
 705         /* Performing lib ring buffer ioctl after our own. */
 706         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 707         if (ret < 0)
 708                 goto err;
 709
 710         switch (cmd) {
 711         case RING_BUFFER_PUT_NEXT_SUBBUF:
 712         {
 713                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 714                                 cmd, arg);
 715                 break;
 716         }
 717         default:
 718                 break;
 719         }
 720 err:
 721         return ret;
 722 }
 723 #endif
 724
 725 /*
 726  * This is not used by anonymous file descriptors. This code is left
 727  * there if we ever want to implement an inode with open() operation.
 728  */
 729 static
 730 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 731 {
 732         struct lttng_metadata_stream *stream = inode->i_private;
 733         struct lib_ring_buffer *buf = stream->priv;
 734
 735         file->private_data = buf;
 736         /*
 737          * Since life-time of metadata cache differs from that of
 738          * session, we need to keep our own reference on the transport.
 739          */
 740         if (!try_module_get(stream->transport->owner)) {
 741                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 742                 return -EBUSY;
 743         }
 744         return lib_ring_buffer_open(inode, file, buf);
 745 }
 746
 747 static
 748 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 749 {
 750         struct lttng_metadata_stream *stream = file->private_data;
 751         struct lib_ring_buffer *buf = stream->priv;
 752
 753         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 754         module_put(stream->transport->owner);
 755         return lib_ring_buffer_release(inode, file, buf);
 756 }
 757
 758 static
 759 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 760                 struct pipe_inode_info *pipe, size_t len,
 761                 unsigned int flags)
 762 {
 763         struct lttng_metadata_stream *stream = in->private_data;
 764         struct lib_ring_buffer *buf = stream->priv;
 765
 766         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 767                         flags, buf);
 768 }
 769
 770 static
 771 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 772                 struct vm_area_struct *vma)
 773 {
 774         struct lttng_metadata_stream *stream = filp->private_data;
 775         struct lib_ring_buffer *buf = stream->priv;
 776
 777         return lib_ring_buffer_mmap(filp, vma, buf);
 778 }
 779
 780 static
 781 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 782         .owner = THIS_MODULE,
 783         .open = lttng_metadata_ring_buffer_open,
 784         .release = lttng_metadata_ring_buffer_release,
 785         .poll = lttng_metadata_ring_buffer_poll,
 786         .splice_read = lttng_metadata_ring_buffer_splice_read,
 787         .mmap = lttng_metadata_ring_buffer_mmap,
 788         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 789         .llseek = vfs_lib_ring_buffer_no_llseek,
 790 #ifdef CONFIG_COMPAT
 791         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 792 #endif
 793 };
 794
 795 static
 796 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 797                 const struct file_operations *fops)
 798 {
 799         int stream_fd, ret;
 800         struct file *stream_file;
 801
 802         stream_fd = get_unused_fd();
 803         if (stream_fd < 0) {
 804                 ret = stream_fd;
 805                 goto fd_error;
 806         }
 807         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 808                         stream_priv, O_RDWR);
 809         if (IS_ERR(stream_file)) {
 810                 ret = PTR_ERR(stream_file);
 811                 goto file_error;
 812         }
 813         /*
 814          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 815          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 816          * file descriptor, so we set FMODE_PREAD here.
 817          */
 818         stream_file->f_mode |= FMODE_PREAD;
 819         fd_install(stream_fd, stream_file);
 820         /*
 821          * The stream holds a reference to the channel within the generic ring
 822          * buffer library, so no need to hold a refcount on the channel and
 823          * session files here.
 824          */
 825         return stream_fd;
 826
 827 file_error:
 828         put_unused_fd(stream_fd);
 829 fd_error:
 830         return ret;
 831 }
 832
 833 static
 834 int lttng_abi_open_stream(struct file *channel_file)
 835 {
 836         struct lttng_channel *channel = channel_file->private_data;
 837         struct lib_ring_buffer *buf;
 838         int ret;
 839         void *stream_priv;
 840
 841         buf = channel->ops->buffer_read_open(channel->chan);
 842         if (!buf)
 843                 return -ENOENT;
 844
 845         stream_priv = buf;
 846         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 847                         &lttng_stream_ring_buffer_file_operations);
 848         if (ret < 0)
 849                 goto fd_error;
 850
 851         return ret;
 852
 853 fd_error:
 854         channel->ops->buffer_read_close(buf);
 855         return ret;
 856 }
 857
 858 static
 859 int lttng_abi_open_metadata_stream(struct file *channel_file)
 860 {
 861         struct lttng_channel *channel = channel_file->private_data;
 862         struct lttng_session *session = channel->session;
 863         struct lib_ring_buffer *buf;
 864         int ret;
 865         struct lttng_metadata_stream *metadata_stream;
 866         void *stream_priv;
 867
 868         buf = channel->ops->buffer_read_open(channel->chan);
 869         if (!buf)
 870                 return -ENOENT;
 871
 872         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 873                         GFP_KERNEL);
 874         if (!metadata_stream) {
 875                 ret = -ENOMEM;
 876                 goto nomem;
 877         }
 878         metadata_stream->metadata_cache = session->metadata_cache;
 879         init_waitqueue_head(&metadata_stream->read_wait);
 880         metadata_stream->priv = buf;
 881         stream_priv = metadata_stream;
 882         metadata_stream->transport = channel->transport;
 883         mutex_init(&metadata_stream->lock);
 884
 885         /*
 886          * Since life-time of metadata cache differs from that of
 887          * session, we need to keep our own reference on the transport.
 888          */
 889         if (!try_module_get(metadata_stream->transport->owner)) {
 890                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 891                 ret = -EINVAL;
 892                 goto notransport;
 893         }
 894
 895         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 896                         &lttng_metadata_ring_buffer_file_operations);
 897         if (ret < 0)
 898                 goto fd_error;
 899
 900         kref_get(&session->metadata_cache->refcount);
 901         list_add(&metadata_stream->list,
 902                 &session->metadata_cache->metadata_stream);
 903         return ret;
 904
 905 fd_error:
 906         module_put(metadata_stream->transport->owner);
 907 notransport:
 908         kfree(metadata_stream);
 909 nomem:
 910         channel->ops->buffer_read_close(buf);
 911         return ret;
 912 }
 913
 914 static
 915 int lttng_abi_create_event(struct file *channel_file,
 916                            struct lttng_kernel_event *event_param)
 917 {
 918         struct lttng_channel *channel = channel_file->private_data;
 919         struct lttng_event *event;
 920         int event_fd, ret;
 921         struct file *event_file;
 922
 923         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 924         switch (event_param->instrumentation) {
 925         case LTTNG_KERNEL_KRETPROBE:
 926                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 927                 break;
 928         case LTTNG_KERNEL_KPROBE:
 929                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 930                 break;
 931         case LTTNG_KERNEL_FUNCTION:
 932                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 933                 break;
 934         default:
 935                 break;
 936         }
 937         switch (event_param->instrumentation) {
 938         default:
 939                 event_fd = get_unused_fd();
 940                 if (event_fd < 0) {
 941                         ret = event_fd;
 942                         goto fd_error;
 943                 }
 944                 event_file = anon_inode_getfile("[lttng_event]",
 945                                                 &lttng_event_fops,
 946                                                 NULL, O_RDWR);
 947                 if (IS_ERR(event_file)) {
 948                         ret = PTR_ERR(event_file);
 949                         goto file_error;
 950                 }
 951                 /*
 952                  * We tolerate no failure path after event creation. It
 953                  * will stay invariant for the rest of the session.
 954                  */
 955                 event = lttng_event_create(channel, event_param, NULL, NULL);
 956                 WARN_ON_ONCE(!event);
 957                 if (IS_ERR(event)) {
 958                         ret = PTR_ERR(event);
 959                         goto event_error;
 960                 }
 961                 event_file->private_data = event;
 962                 fd_install(event_fd, event_file);
 963                 /* The event holds a reference on the channel */
 964                 atomic_long_inc(&channel_file->f_count);
 965                 break;
 966         case LTTNG_KERNEL_SYSCALL:
 967                 ret = lttng_syscalls_register(channel, NULL);
 968                 if (ret)
 969                         goto fd_error;
 970                 event_fd = 0;
 971                 if (event_param->u.syscall.disable) {
 972                         ret = lttng_syscall_filter_disable(channel,
 973                                 event_param->name[0] == '\0' ?
 974                                         NULL : event_param->name);
 975                         if (ret)
 976                                 goto fd_error;
 977                 } else {
 978                         ret = lttng_syscall_filter_enable(channel,
 979                                 event_param->name[0] == '\0' ?
 980                                         NULL : event_param->name);
 981                         if (ret)
 982                                 goto fd_error;
 983                 }
 984                 break;
 985         }
 986         return event_fd;
 987
 988 event_error:
 989         fput(event_file);
 990 file_error:
 991         put_unused_fd(event_fd);
 992 fd_error:
 993         return ret;
 994 }
 995
 996 /**
 997  *      lttng_channel_ioctl - lttng syscall through ioctl
 998  *
 999  *      @file: the file
1000  *      @cmd: the command
1001  *      @arg: command arg
1002  *
1003  *      This ioctl implements lttng commands:
1004  *      LTTNG_KERNEL_STREAM
1005  *              Returns an event stream file descriptor or failure.
1006  *              (typically, one event stream records events from one CPU)
1007  *      LTTNG_KERNEL_EVENT
1008  *              Returns an event file descriptor or failure.
1009  *      LTTNG_KERNEL_CONTEXT
1010  *              Prepend a context field to each event in the channel
1011  *      LTTNG_KERNEL_ENABLE
1012  *              Enable recording for events in this channel (weak enable)
1013  *      LTTNG_KERNEL_DISABLE
1014  *              Disable recording for events in this channel (strong disable)
1015  *
1016  * Channel and event file descriptors also hold a reference on the session.
1017  */
1018 static
1019 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1020 {
1021         struct lttng_channel *channel = file->private_data;
1022
1023         switch (cmd) {
1024         case LTTNG_KERNEL_OLD_STREAM:
1025         case LTTNG_KERNEL_STREAM:
1026                 return lttng_abi_open_stream(file);
1027         case LTTNG_KERNEL_OLD_EVENT:
1028         {
1029                 struct lttng_kernel_event *uevent_param;
1030                 struct lttng_kernel_old_event *old_uevent_param;
1031                 int ret;
1032
1033                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1034                                 GFP_KERNEL);
1035                 if (!uevent_param) {
1036                         ret = -ENOMEM;
1037                         goto old_event_end;
1038                 }
1039                 old_uevent_param = kmalloc(
1040                                 sizeof(struct lttng_kernel_old_event),
1041                                 GFP_KERNEL);
1042                 if (!old_uevent_param) {
1043                         ret = -ENOMEM;
1044                         goto old_event_error_free_param;
1045                 }
1046                 if (copy_from_user(old_uevent_param,
1047                                 (struct lttng_kernel_old_event __user *) arg,
1048                                 sizeof(struct lttng_kernel_old_event))) {
1049                         ret = -EFAULT;
1050                         goto old_event_error_free_old_param;
1051                 }
1052
1053                 memcpy(uevent_param->name, old_uevent_param->name,
1054                                 sizeof(uevent_param->name));
1055                 uevent_param->instrumentation =
1056                         old_uevent_param->instrumentation;
1057
1058                 switch (old_uevent_param->instrumentation) {
1059                 case LTTNG_KERNEL_KPROBE:
1060                         uevent_param->u.kprobe.addr =
1061                                 old_uevent_param->u.kprobe.addr;
1062                         uevent_param->u.kprobe.offset =
1063                                 old_uevent_param->u.kprobe.offset;
1064                         memcpy(uevent_param->u.kprobe.symbol_name,
1065                                 old_uevent_param->u.kprobe.symbol_name,
1066                                 sizeof(uevent_param->u.kprobe.symbol_name));
1067                         break;
1068                 case LTTNG_KERNEL_KRETPROBE:
1069                         uevent_param->u.kretprobe.addr =
1070                                 old_uevent_param->u.kretprobe.addr;
1071                         uevent_param->u.kretprobe.offset =
1072                                 old_uevent_param->u.kretprobe.offset;
1073                         memcpy(uevent_param->u.kretprobe.symbol_name,
1074                                 old_uevent_param->u.kretprobe.symbol_name,
1075                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1076                         break;
1077                 case LTTNG_KERNEL_FUNCTION:
1078                         memcpy(uevent_param->u.ftrace.symbol_name,
1079                                         old_uevent_param->u.ftrace.symbol_name,
1080                                         sizeof(uevent_param->u.ftrace.symbol_name));
1081                         break;
1082                 default:
1083                         break;
1084                 }
1085                 ret = lttng_abi_create_event(file, uevent_param);
1086
1087 old_event_error_free_old_param:
1088                 kfree(old_uevent_param);
1089 old_event_error_free_param:
1090                 kfree(uevent_param);
1091 old_event_end:
1092                 return ret;
1093         }
1094         case LTTNG_KERNEL_EVENT:
1095         {
1096                 struct lttng_kernel_event uevent_param;
1097
1098                 if (copy_from_user(&uevent_param,
1099                                 (struct lttng_kernel_event __user *) arg,
1100                                 sizeof(uevent_param)))
1101                         return -EFAULT;
1102                 return lttng_abi_create_event(file, &uevent_param);
1103         }
1104         case LTTNG_KERNEL_OLD_CONTEXT:
1105         {
1106                 struct lttng_kernel_context *ucontext_param;
1107                 struct lttng_kernel_old_context *old_ucontext_param;
1108                 int ret;
1109
1110                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1111                                 GFP_KERNEL);
1112                 if (!ucontext_param) {
1113                         ret = -ENOMEM;
1114                         goto old_ctx_end;
1115                 }
1116                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1117                                 GFP_KERNEL);
1118                 if (!old_ucontext_param) {
1119                         ret = -ENOMEM;
1120                         goto old_ctx_error_free_param;
1121                 }
1122
1123                 if (copy_from_user(old_ucontext_param,
1124                                 (struct lttng_kernel_old_context __user *) arg,
1125                                 sizeof(struct lttng_kernel_old_context))) {
1126                         ret = -EFAULT;
1127                         goto old_ctx_error_free_old_param;
1128                 }
1129                 ucontext_param->ctx = old_ucontext_param->ctx;
1130                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1131                                 sizeof(ucontext_param->padding));
1132                 /* only type that uses the union */
1133                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1134                         ucontext_param->u.perf_counter.type =
1135                                 old_ucontext_param->u.perf_counter.type;
1136                         ucontext_param->u.perf_counter.config =
1137                                 old_ucontext_param->u.perf_counter.config;
1138                         memcpy(ucontext_param->u.perf_counter.name,
1139                                 old_ucontext_param->u.perf_counter.name,
1140                                 sizeof(ucontext_param->u.perf_counter.name));
1141                 }
1142
1143                 ret = lttng_abi_add_context(file,
1144                                 ucontext_param,
1145                                 &channel->ctx, channel->session);
1146
1147 old_ctx_error_free_old_param:
1148                 kfree(old_ucontext_param);
1149 old_ctx_error_free_param:
1150                 kfree(ucontext_param);
1151 old_ctx_end:
1152                 return ret;
1153         }
1154         case LTTNG_KERNEL_CONTEXT:
1155         {
1156                 struct lttng_kernel_context ucontext_param;
1157
1158                 if (copy_from_user(&ucontext_param,
1159                                 (struct lttng_kernel_context __user *) arg,
1160                                 sizeof(ucontext_param)))
1161                         return -EFAULT;
1162                 return lttng_abi_add_context(file,
1163                                 &ucontext_param,
1164                                 &channel->ctx, channel->session);
1165         }
1166         case LTTNG_KERNEL_OLD_ENABLE:
1167         case LTTNG_KERNEL_ENABLE:
1168                 return lttng_channel_enable(channel);
1169         case LTTNG_KERNEL_OLD_DISABLE:
1170         case LTTNG_KERNEL_DISABLE:
1171                 return lttng_channel_disable(channel);
1172         default:
1173                 return -ENOIOCTLCMD;
1174         }
1175
1176 }
1177
1178 /**
1179  *      lttng_metadata_ioctl - lttng syscall through ioctl
1180  *
1181  *      @file: the file
1182  *      @cmd: the command
1183  *      @arg: command arg
1184  *
1185  *      This ioctl implements lttng commands:
1186  *      LTTNG_KERNEL_STREAM
1187  *              Returns an event stream file descriptor or failure.
1188  *
1189  * Channel and event file descriptors also hold a reference on the session.
1190  */
1191 static
1192 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1193 {
1194         switch (cmd) {
1195         case LTTNG_KERNEL_OLD_STREAM:
1196         case LTTNG_KERNEL_STREAM:
1197                 return lttng_abi_open_metadata_stream(file);
1198         default:
1199                 return -ENOIOCTLCMD;
1200         }
1201 }
1202
1203 /**
1204  *      lttng_channel_poll - lttng stream addition/removal monitoring
1205  *
1206  *      @file: the file
1207  *      @wait: poll table
1208  */
1209 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1210 {
1211         struct lttng_channel *channel = file->private_data;
1212         unsigned int mask = 0;
1213
1214         if (file->f_mode & FMODE_READ) {
1215                 poll_wait_set_exclusive(wait);
1216                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1217                           wait);
1218
1219                 if (channel->ops->is_disabled(channel->chan))
1220                         return POLLERR;
1221                 if (channel->ops->is_finalized(channel->chan))
1222                         return POLLHUP;
1223                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1224                         return POLLIN | POLLRDNORM;
1225                 return 0;
1226         }
1227         return mask;
1228
1229 }
1230
1231 static
1232 int lttng_channel_release(struct inode *inode, struct file *file)
1233 {
1234         struct lttng_channel *channel = file->private_data;
1235
1236         if (channel)
1237                 fput(channel->session->file);
1238         return 0;
1239 }
1240
1241 static
1242 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1243 {
1244         struct lttng_channel *channel = file->private_data;
1245
1246         if (channel) {
1247                 lttng_metadata_channel_destroy(channel);
1248                 fput(channel->session->file);
1249         }
1250
1251         return 0;
1252 }
1253
1254 static const struct file_operations lttng_channel_fops = {
1255         .owner = THIS_MODULE,
1256         .release = lttng_channel_release,
1257         .poll = lttng_channel_poll,
1258         .unlocked_ioctl = lttng_channel_ioctl,
1259 #ifdef CONFIG_COMPAT
1260         .compat_ioctl = lttng_channel_ioctl,
1261 #endif
1262 };
1263
1264 static const struct file_operations lttng_metadata_fops = {
1265         .owner = THIS_MODULE,
1266         .release = lttng_metadata_channel_release,
1267         .unlocked_ioctl = lttng_metadata_ioctl,
1268 #ifdef CONFIG_COMPAT
1269         .compat_ioctl = lttng_metadata_ioctl,
1270 #endif
1271 };
1272
1273 /**
1274  *      lttng_event_ioctl - lttng syscall through ioctl
1275  *
1276  *      @file: the file
1277  *      @cmd: the command
1278  *      @arg: command arg
1279  *
1280  *      This ioctl implements lttng commands:
1281  *      LTTNG_KERNEL_CONTEXT
1282  *              Prepend a context field to each record of this event
1283  *      LTTNG_KERNEL_ENABLE
1284  *              Enable recording for this event (weak enable)
1285  *      LTTNG_KERNEL_DISABLE
1286  *              Disable recording for this event (strong disable)
1287  */
1288 static
1289 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1290 {
1291         struct lttng_event *event = file->private_data;
1292
1293         switch (cmd) {
1294         case LTTNG_KERNEL_OLD_CONTEXT:
1295         {
1296                 struct lttng_kernel_context *ucontext_param;
1297                 struct lttng_kernel_old_context *old_ucontext_param;
1298                 int ret;
1299
1300                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1301                                 GFP_KERNEL);
1302                 if (!ucontext_param) {
1303                         ret = -ENOMEM;
1304                         goto old_ctx_end;
1305                 }
1306                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1307                                 GFP_KERNEL);
1308                 if (!old_ucontext_param) {
1309                         ret = -ENOMEM;
1310                         goto old_ctx_error_free_param;
1311                 }
1312
1313                 if (copy_from_user(old_ucontext_param,
1314                                         (struct lttng_kernel_old_context __user *) arg,
1315                                         sizeof(struct lttng_kernel_old_context))) {
1316                         ret = -EFAULT;
1317                         goto old_ctx_error_free_old_param;
1318                 }
1319                 ucontext_param->ctx = old_ucontext_param->ctx;
1320                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1321                                 sizeof(ucontext_param->padding));
1322                 /* only type that uses the union */
1323                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1324                         ucontext_param->u.perf_counter.type =
1325                                 old_ucontext_param->u.perf_counter.type;
1326                         ucontext_param->u.perf_counter.config =
1327                                 old_ucontext_param->u.perf_counter.config;
1328                         memcpy(ucontext_param->u.perf_counter.name,
1329                                         old_ucontext_param->u.perf_counter.name,
1330                                         sizeof(ucontext_param->u.perf_counter.name));
1331                 }
1332
1333                 ret = lttng_abi_add_context(file,
1334                                 ucontext_param,
1335                                 &event->ctx, event->chan->session);
1336
1337 old_ctx_error_free_old_param:
1338                 kfree(old_ucontext_param);
1339 old_ctx_error_free_param:
1340                 kfree(ucontext_param);
1341 old_ctx_end:
1342                 return ret;
1343         }
1344         case LTTNG_KERNEL_CONTEXT:
1345         {
1346                 struct lttng_kernel_context ucontext_param;
1347
1348                 if (copy_from_user(&ucontext_param,
1349                                         (struct lttng_kernel_context __user *) arg,
1350                                         sizeof(ucontext_param)))
1351                         return -EFAULT;
1352                 return lttng_abi_add_context(file,
1353                                 &ucontext_param,
1354                                 &event->ctx, event->chan->session);
1355         }
1356         case LTTNG_KERNEL_OLD_ENABLE:
1357         case LTTNG_KERNEL_ENABLE:
1358                 return lttng_event_enable(event);
1359         case LTTNG_KERNEL_OLD_DISABLE:
1360         case LTTNG_KERNEL_DISABLE:
1361                 return lttng_event_disable(event);
1362         default:
1363                 return -ENOIOCTLCMD;
1364         }
1365 }
1366
1367 static
1368 int lttng_event_release(struct inode *inode, struct file *file)
1369 {
1370         struct lttng_event *event = file->private_data;
1371
1372         if (event)
1373                 fput(event->chan->file);
1374         return 0;
1375 }
1376
1377 /* TODO: filter control ioctl */
1378 static const struct file_operations lttng_event_fops = {
1379         .owner = THIS_MODULE,
1380         .release = lttng_event_release,
1381         .unlocked_ioctl = lttng_event_ioctl,
1382 #ifdef CONFIG_COMPAT
1383         .compat_ioctl = lttng_event_ioctl,
1384 #endif
1385 };
1386
1387 static int put_u64(uint64_t val, unsigned long arg)
1388 {
1389         return put_user(val, (uint64_t __user *) arg);
1390 }
1391
1392 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1393                 unsigned int cmd, unsigned long arg)
1394 {
1395         struct lib_ring_buffer *buf = filp->private_data;
1396         struct channel *chan = buf->backend.chan;
1397         const struct lib_ring_buffer_config *config = &chan->backend.config;
1398         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1399         int ret;
1400
1401         if (atomic_read(&chan->record_disabled))
1402                 return -EIO;
1403
1404         switch (cmd) {
1405         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1406         {
1407                 uint64_t ts;
1408
1409                 ret = ops->timestamp_begin(config, buf, &ts);
1410                 if (ret < 0)
1411                         goto error;
1412                 return put_u64(ts, arg);
1413         }
1414         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1415         {
1416                 uint64_t ts;
1417
1418                 ret = ops->timestamp_end(config, buf, &ts);
1419                 if (ret < 0)
1420                         goto error;
1421                 return put_u64(ts, arg);
1422         }
1423         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1424         {
1425                 uint64_t ed;
1426
1427                 ret = ops->events_discarded(config, buf, &ed);
1428                 if (ret < 0)
1429                         goto error;
1430                 return put_u64(ed, arg);
1431         }
1432         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1433         {
1434                 uint64_t cs;
1435
1436                 ret = ops->content_size(config, buf, &cs);
1437                 if (ret < 0)
1438                         goto error;
1439                 return put_u64(cs, arg);
1440         }
1441         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1442         {
1443                 uint64_t ps;
1444
1445                 ret = ops->packet_size(config, buf, &ps);
1446                 if (ret < 0)
1447                         goto error;
1448                 return put_u64(ps, arg);
1449         }
1450         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1451         {
1452                 uint64_t si;
1453
1454                 ret = ops->stream_id(config, buf, &si);
1455                 if (ret < 0)
1456                         goto error;
1457                 return put_u64(si, arg);
1458         }
1459         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1460         {
1461                 uint64_t ts;
1462
1463                 ret = ops->current_timestamp(config, buf, &ts);
1464                 if (ret < 0)
1465                         goto error;
1466                 return put_u64(ts, arg);
1467         }
1468         default:
1469                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1470                                 cmd, arg);
1471         }
1472
1473 error:
1474         return -ENOSYS;
1475 }
1476
1477 #ifdef CONFIG_COMPAT
1478 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1479                 unsigned int cmd, unsigned long arg)
1480 {
1481         struct lib_ring_buffer *buf = filp->private_data;
1482         struct channel *chan = buf->backend.chan;
1483         const struct lib_ring_buffer_config *config = &chan->backend.config;
1484         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1485         int ret;
1486
1487         if (atomic_read(&chan->record_disabled))
1488                 return -EIO;
1489
1490         switch (cmd) {
1491         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1492         {
1493                 uint64_t ts;
1494
1495                 ret = ops->timestamp_begin(config, buf, &ts);
1496                 if (ret < 0)
1497                         goto error;
1498                 return put_u64(ts, arg);
1499         }
1500         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1501         {
1502                 uint64_t ts;
1503
1504                 ret = ops->timestamp_end(config, buf, &ts);
1505                 if (ret < 0)
1506                         goto error;
1507                 return put_u64(ts, arg);
1508         }
1509         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1510         {
1511                 uint64_t ed;
1512
1513                 ret = ops->events_discarded(config, buf, &ed);
1514                 if (ret < 0)
1515                         goto error;
1516                 return put_u64(ed, arg);
1517         }
1518         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1519         {
1520                 uint64_t cs;
1521
1522                 ret = ops->content_size(config, buf, &cs);
1523                 if (ret < 0)
1524                         goto error;
1525                 return put_u64(cs, arg);
1526         }
1527         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1528         {
1529                 uint64_t ps;
1530
1531                 ret = ops->packet_size(config, buf, &ps);
1532                 if (ret < 0)
1533                         goto error;
1534                 return put_u64(ps, arg);
1535         }
1536         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1537         {
1538                 uint64_t si;
1539
1540                 ret = ops->stream_id(config, buf, &si);
1541                 if (ret < 0)
1542                         goto error;
1543                 return put_u64(si, arg);
1544         }
1545         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1546         {
1547                 uint64_t ts;
1548
1549                 ret = ops->current_timestamp(config, buf, &ts);
1550                 if (ret < 0)
1551                         goto error;
1552                 return put_u64(ts, arg);
1553         }
1554         default:
1555                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1556                                 cmd, arg);
1557         }
1558
1559 error:
1560         return -ENOSYS;
1561 }
1562 #endif /* CONFIG_COMPAT */
1563
1564 static void lttng_stream_override_ring_buffer_fops(void)
1565 {
1566         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1567         lttng_stream_ring_buffer_file_operations.open =
1568                 lib_ring_buffer_file_operations.open;
1569         lttng_stream_ring_buffer_file_operations.release =
1570                 lib_ring_buffer_file_operations.release;
1571         lttng_stream_ring_buffer_file_operations.poll =
1572                 lib_ring_buffer_file_operations.poll;
1573         lttng_stream_ring_buffer_file_operations.splice_read =
1574                 lib_ring_buffer_file_operations.splice_read;
1575         lttng_stream_ring_buffer_file_operations.mmap =
1576                 lib_ring_buffer_file_operations.mmap;
1577         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1578                 lttng_stream_ring_buffer_ioctl;
1579         lttng_stream_ring_buffer_file_operations.llseek =
1580                 lib_ring_buffer_file_operations.llseek;
1581 #ifdef CONFIG_COMPAT
1582         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1583                 lttng_stream_ring_buffer_compat_ioctl;
1584 #endif
1585 }
1586
1587 int __init lttng_abi_init(void)
1588 {
1589         int ret = 0;
1590
1591         wrapper_vmalloc_sync_all();
1592         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1593                                         &lttng_fops, NULL);
1594
1595         if (!lttng_proc_dentry) {
1596                 printk(KERN_ERR "Error creating LTTng control file\n");
1597                 ret = -ENOMEM;
1598                 goto error;
1599         }
1600         lttng_stream_override_ring_buffer_fops();
1601
1602 error:
1603         return ret;
1604 }
1605
1606 /* No __exit annotation because used by init error path too. */
1607 void lttng_abi_exit(void)
1608 {
1609         if (lttng_proc_dentry)
1610                 remove_proc_entry("lttng", NULL);
1611 }