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 "wrapper/file.h"
  53 #include "lttng-abi.h"
  54 #include "lttng-abi-old.h"
  55 #include "lttng-events.h"
  56 #include "lttng-tracer.h"
  57 #include "lib/ringbuffer/frontend_types.h"
  58
  59 /*
  60  * This is LTTng's own personal way to create a system call as an external
  61  * module. We use ioctl() on /proc/lttng.
  62  */
  63
  64 static struct proc_dir_entry *lttng_proc_dentry;
  65 static const struct file_operations lttng_fops;
  66 static const struct file_operations lttng_session_fops;
  67 static const struct file_operations lttng_channel_fops;
  68 static const struct file_operations lttng_metadata_fops;
  69 static const struct file_operations lttng_event_fops;
  70 static struct file_operations lttng_stream_ring_buffer_file_operations;
  71
  72 /*
  73  * Teardown management: opened file descriptors keep a refcount on the module,
  74  * so it can only exit when all file descriptors are closed.
  75  */
  76
  77 static
  78 int lttng_abi_create_session(void)
  79 {
  80         struct lttng_session *session;
  81         struct file *session_file;
  82         int session_fd, ret;
  83
  84         session = lttng_session_create();
  85         if (!session)
  86                 return -ENOMEM;
  87         session_fd = lttng_get_unused_fd();
  88         if (session_fd < 0) {
  89                 ret = session_fd;
  90                 goto fd_error;
  91         }
  92         session_file = anon_inode_getfile("[lttng_session]",
  93                                           &lttng_session_fops,
  94                                           session, O_RDWR);
  95         if (IS_ERR(session_file)) {
  96                 ret = PTR_ERR(session_file);
  97                 goto file_error;
  98         }
  99         session->file = session_file;
 100         fd_install(session_fd, session_file);
 101         return session_fd;
 102
 103 file_error:
 104         put_unused_fd(session_fd);
 105 fd_error:
 106         lttng_session_destroy(session);
 107         return ret;
 108 }
 109
 110 static
 111 int lttng_abi_tracepoint_list(void)
 112 {
 113         struct file *tracepoint_list_file;
 114         int file_fd, ret;
 115
 116         file_fd = lttng_get_unused_fd();
 117         if (file_fd < 0) {
 118                 ret = file_fd;
 119                 goto fd_error;
 120         }
 121
 122         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 123                                           &lttng_tracepoint_list_fops,
 124                                           NULL, O_RDWR);
 125         if (IS_ERR(tracepoint_list_file)) {
 126                 ret = PTR_ERR(tracepoint_list_file);
 127                 goto file_error;
 128         }
 129         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 130         if (ret < 0)
 131                 goto open_error;
 132         fd_install(file_fd, tracepoint_list_file);
 133         if (file_fd < 0) {
 134                 ret = file_fd;
 135                 goto fd_error;
 136         }
 137         return file_fd;
 138
 139 open_error:
 140         fput(tracepoint_list_file);
 141 file_error:
 142         put_unused_fd(file_fd);
 143 fd_error:
 144         return ret;
 145 }
 146
 147 static
 148 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 149 {
 150         v->major = LTTNG_MODULES_MAJOR_VERSION;
 151         v->minor = LTTNG_MODULES_MINOR_VERSION;
 152         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 153 }
 154
 155 static
 156 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 157 {
 158         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 159         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 160 }
 161
 162 static
 163 long lttng_abi_add_context(struct file *file,
 164         struct lttng_kernel_context *context_param,
 165         struct lttng_ctx **ctx, struct lttng_session *session)
 166 {
 167
 168         if (session->been_active)
 169                 return -EPERM;
 170
 171         switch (context_param->ctx) {
 172         case LTTNG_KERNEL_CONTEXT_PID:
 173                 return lttng_add_pid_to_ctx(ctx);
 174         case LTTNG_KERNEL_CONTEXT_PRIO:
 175                 return lttng_add_prio_to_ctx(ctx);
 176         case LTTNG_KERNEL_CONTEXT_NICE:
 177                 return lttng_add_nice_to_ctx(ctx);
 178         case LTTNG_KERNEL_CONTEXT_VPID:
 179                 return lttng_add_vpid_to_ctx(ctx);
 180         case LTTNG_KERNEL_CONTEXT_TID:
 181                 return lttng_add_tid_to_ctx(ctx);
 182         case LTTNG_KERNEL_CONTEXT_VTID:
 183                 return lttng_add_vtid_to_ctx(ctx);
 184         case LTTNG_KERNEL_CONTEXT_PPID:
 185                 return lttng_add_ppid_to_ctx(ctx);
 186         case LTTNG_KERNEL_CONTEXT_VPPID:
 187                 return lttng_add_vppid_to_ctx(ctx);
 188         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 189                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 190                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 191                                 context_param->u.perf_counter.config,
 192                                 context_param->u.perf_counter.name,
 193                                 ctx);
 194         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 195                 return lttng_add_procname_to_ctx(ctx);
 196         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 197                 return lttng_add_hostname_to_ctx(ctx);
 198         default:
 199                 return -EINVAL;
 200         }
 201 }
 202
 203 /**
 204  *      lttng_ioctl - lttng syscall through ioctl
 205  *
 206  *      @file: the file
 207  *      @cmd: the command
 208  *      @arg: command arg
 209  *
 210  *      This ioctl implements lttng commands:
 211  *      LTTNG_KERNEL_SESSION
 212  *              Returns a LTTng trace session file descriptor
 213  *      LTTNG_KERNEL_TRACER_VERSION
 214  *              Returns the LTTng kernel tracer version
 215  *      LTTNG_KERNEL_TRACEPOINT_LIST
 216  *              Returns a file descriptor listing available tracepoints
 217  *      LTTNG_KERNEL_WAIT_QUIESCENT
 218  *              Returns after all previously running probes have completed
 219  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 220  *              Returns the LTTng kernel tracer ABI version
 221  *
 222  * The returned session will be deleted when its file descriptor is closed.
 223  */
 224 static
 225 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 226 {
 227         switch (cmd) {
 228         case LTTNG_KERNEL_OLD_SESSION:
 229         case LTTNG_KERNEL_SESSION:
 230                 return lttng_abi_create_session();
 231         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 232         {
 233                 struct lttng_kernel_tracer_version v;
 234                 struct lttng_kernel_old_tracer_version oldv;
 235                 struct lttng_kernel_old_tracer_version *uversion =
 236                         (struct lttng_kernel_old_tracer_version __user *) arg;
 237
 238                 lttng_abi_tracer_version(&v);
 239                 oldv.major = v.major;
 240                 oldv.minor = v.minor;
 241                 oldv.patchlevel = v.patchlevel;
 242
 243                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 244                         return -EFAULT;
 245                 return 0;
 246         }
 247         case LTTNG_KERNEL_TRACER_VERSION:
 248         {
 249                 struct lttng_kernel_tracer_version version;
 250                 struct lttng_kernel_tracer_version *uversion =
 251                         (struct lttng_kernel_tracer_version __user *) arg;
 252
 253                 lttng_abi_tracer_version(&version);
 254
 255                 if (copy_to_user(uversion, &version, sizeof(version)))
 256                         return -EFAULT;
 257                 return 0;
 258         }
 259         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 260         {
 261                 struct lttng_kernel_tracer_abi_version version;
 262                 struct lttng_kernel_tracer_abi_version *uversion =
 263                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 264
 265                 lttng_abi_tracer_abi_version(&version);
 266
 267                 if (copy_to_user(uversion, &version, sizeof(version)))
 268                         return -EFAULT;
 269                 return 0;
 270         }
 271         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 272         case LTTNG_KERNEL_TRACEPOINT_LIST:
 273                 return lttng_abi_tracepoint_list();
 274         case LTTNG_KERNEL_SYSCALL_LIST:
 275                 return lttng_abi_syscall_list();
 276         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 277         case LTTNG_KERNEL_WAIT_QUIESCENT:
 278                 synchronize_trace();
 279                 return 0;
 280         case LTTNG_KERNEL_OLD_CALIBRATE:
 281         {
 282                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 283                         (struct lttng_kernel_old_calibrate __user *) arg;
 284                 struct lttng_kernel_old_calibrate old_calibrate;
 285                 struct lttng_kernel_calibrate calibrate;
 286                 int ret;
 287
 288                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 289                         return -EFAULT;
 290                 calibrate.type = old_calibrate.type;
 291                 ret = lttng_calibrate(&calibrate);
 292                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 293                         return -EFAULT;
 294                 return ret;
 295         }
 296         case LTTNG_KERNEL_CALIBRATE:
 297         {
 298                 struct lttng_kernel_calibrate __user *ucalibrate =
 299                         (struct lttng_kernel_calibrate __user *) arg;
 300                 struct lttng_kernel_calibrate calibrate;
 301                 int ret;
 302
 303                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 304                         return -EFAULT;
 305                 ret = lttng_calibrate(&calibrate);
 306                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 307                         return -EFAULT;
 308                 return ret;
 309         }
 310         default:
 311                 return -ENOIOCTLCMD;
 312         }
 313 }
 314
 315 static const struct file_operations lttng_fops = {
 316         .owner = THIS_MODULE,
 317         .unlocked_ioctl = lttng_ioctl,
 318 #ifdef CONFIG_COMPAT
 319         .compat_ioctl = lttng_ioctl,
 320 #endif
 321 };
 322
 323 static
 324 int lttng_abi_create_channel(struct file *session_file,
 325                              struct lttng_kernel_channel *chan_param,
 326                              enum channel_type channel_type)
 327 {
 328         struct lttng_session *session = session_file->private_data;
 329         const struct file_operations *fops = NULL;
 330         const char *transport_name;
 331         struct lttng_channel *chan;
 332         struct file *chan_file;
 333         int chan_fd;
 334         int ret = 0;
 335
 336         chan_fd = lttng_get_unused_fd();
 337         if (chan_fd < 0) {
 338                 ret = chan_fd;
 339                 goto fd_error;
 340         }
 341         switch (channel_type) {
 342         case PER_CPU_CHANNEL:
 343                 fops = &lttng_channel_fops;
 344                 break;
 345         case METADATA_CHANNEL:
 346                 fops = &lttng_metadata_fops;
 347                 break;
 348         }
 349
 350         chan_file = anon_inode_getfile("[lttng_channel]",
 351                                        fops,
 352                                        NULL, O_RDWR);
 353         if (IS_ERR(chan_file)) {
 354                 ret = PTR_ERR(chan_file);
 355                 goto file_error;
 356         }
 357         switch (channel_type) {
 358         case PER_CPU_CHANNEL:
 359                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 360                         transport_name = chan_param->overwrite ?
 361                                 "relay-overwrite" : "relay-discard";
 362                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 363                         transport_name = chan_param->overwrite ?
 364                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 365                 } else {
 366                         return -EINVAL;
 367                 }
 368                 break;
 369         case METADATA_CHANNEL:
 370                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 371                         transport_name = "relay-metadata";
 372                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 373                         transport_name = "relay-metadata-mmap";
 374                 else
 375                         return -EINVAL;
 376                 break;
 377         default:
 378                 transport_name = "<unknown>";
 379                 break;
 380         }
 381         /*
 382          * We tolerate no failure path after channel creation. It will stay
 383          * invariant for the rest of the session.
 384          */
 385         chan = lttng_channel_create(session, transport_name, NULL,
 386                                   chan_param->subbuf_size,
 387                                   chan_param->num_subbuf,
 388                                   chan_param->switch_timer_interval,
 389                                   chan_param->read_timer_interval,
 390                                   channel_type);
 391         if (!chan) {
 392                 ret = -EINVAL;
 393                 goto chan_error;
 394         }
 395         chan->file = chan_file;
 396         chan_file->private_data = chan;
 397         fd_install(chan_fd, chan_file);
 398         atomic_long_inc(&session_file->f_count);
 399
 400         return chan_fd;
 401
 402 chan_error:
 403         fput(chan_file);
 404 file_error:
 405         put_unused_fd(chan_fd);
 406 fd_error:
 407         return ret;
 408 }
 409
 410 /**
 411  *      lttng_session_ioctl - lttng session fd ioctl
 412  *
 413  *      @file: the file
 414  *      @cmd: the command
 415  *      @arg: command arg
 416  *
 417  *      This ioctl implements lttng commands:
 418  *      LTTNG_KERNEL_CHANNEL
 419  *              Returns a LTTng channel file descriptor
 420  *      LTTNG_KERNEL_ENABLE
 421  *              Enables tracing for a session (weak enable)
 422  *      LTTNG_KERNEL_DISABLE
 423  *              Disables tracing for a session (strong disable)
 424  *      LTTNG_KERNEL_METADATA
 425  *              Returns a LTTng metadata file descriptor
 426  *
 427  * The returned channel will be deleted when its file descriptor is closed.
 428  */
 429 static
 430 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 431 {
 432         struct lttng_session *session = file->private_data;
 433
 434         switch (cmd) {
 435         case LTTNG_KERNEL_OLD_CHANNEL:
 436         {
 437                 struct lttng_kernel_channel chan_param;
 438                 struct lttng_kernel_old_channel old_chan_param;
 439
 440                 if (copy_from_user(&old_chan_param,
 441                                 (struct lttng_kernel_old_channel __user *) arg,
 442                                 sizeof(struct lttng_kernel_old_channel)))
 443                         return -EFAULT;
 444                 chan_param.overwrite = old_chan_param.overwrite;
 445                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 446                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 447                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 448                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 449                 chan_param.output = old_chan_param.output;
 450
 451                 return lttng_abi_create_channel(file, &chan_param,
 452                                 PER_CPU_CHANNEL);
 453         }
 454         case LTTNG_KERNEL_CHANNEL:
 455         {
 456                 struct lttng_kernel_channel chan_param;
 457
 458                 if (copy_from_user(&chan_param,
 459                                 (struct lttng_kernel_channel __user *) arg,
 460                                 sizeof(struct lttng_kernel_channel)))
 461                         return -EFAULT;
 462                 return lttng_abi_create_channel(file, &chan_param,
 463                                 PER_CPU_CHANNEL);
 464         }
 465         case LTTNG_KERNEL_OLD_SESSION_START:
 466         case LTTNG_KERNEL_OLD_ENABLE:
 467         case LTTNG_KERNEL_SESSION_START:
 468         case LTTNG_KERNEL_ENABLE:
 469                 return lttng_session_enable(session);
 470         case LTTNG_KERNEL_OLD_SESSION_STOP:
 471         case LTTNG_KERNEL_OLD_DISABLE:
 472         case LTTNG_KERNEL_SESSION_STOP:
 473         case LTTNG_KERNEL_DISABLE:
 474                 return lttng_session_disable(session);
 475         case LTTNG_KERNEL_OLD_METADATA:
 476         {
 477                 struct lttng_kernel_channel chan_param;
 478                 struct lttng_kernel_old_channel old_chan_param;
 479
 480                 if (copy_from_user(&old_chan_param,
 481                                 (struct lttng_kernel_old_channel __user *) arg,
 482                                 sizeof(struct lttng_kernel_old_channel)))
 483                         return -EFAULT;
 484                 chan_param.overwrite = old_chan_param.overwrite;
 485                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 486                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 487                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 488                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 489                 chan_param.output = old_chan_param.output;
 490
 491                 return lttng_abi_create_channel(file, &chan_param,
 492                                 METADATA_CHANNEL);
 493         }
 494         case LTTNG_KERNEL_METADATA:
 495         {
 496                 struct lttng_kernel_channel chan_param;
 497
 498                 if (copy_from_user(&chan_param,
 499                                         (struct lttng_kernel_channel __user *) arg,
 500                                         sizeof(struct lttng_kernel_channel)))
 501                         return -EFAULT;
 502                 return lttng_abi_create_channel(file, &chan_param,
 503                                 METADATA_CHANNEL);
 504         }
 505         default:
 506                 return -ENOIOCTLCMD;
 507         }
 508 }
 509
 510 /*
 511  * Called when the last file reference is dropped.
 512  *
 513  * Big fat note: channels and events are invariant for the whole session after
 514  * their creation. So this session destruction also destroys all channel and
 515  * event structures specific to this session (they are not destroyed when their
 516  * individual file is released).
 517  */
 518 static
 519 int lttng_session_release(struct inode *inode, struct file *file)
 520 {
 521         struct lttng_session *session = file->private_data;
 522
 523         if (session)
 524                 lttng_session_destroy(session);
 525         return 0;
 526 }
 527
 528 static const struct file_operations lttng_session_fops = {
 529         .owner = THIS_MODULE,
 530         .release = lttng_session_release,
 531         .unlocked_ioctl = lttng_session_ioctl,
 532 #ifdef CONFIG_COMPAT
 533         .compat_ioctl = lttng_session_ioctl,
 534 #endif
 535 };
 536
 537 /**
 538  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 539  *      @filp: the file
 540  *      @wait: poll table
 541  *
 542  *      Handles the poll operations for the metadata channels.
 543  */
 544 static
 545 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 546                 poll_table *wait)
 547 {
 548         struct lttng_metadata_stream *stream = filp->private_data;
 549         struct lib_ring_buffer *buf = stream->priv;
 550         int finalized;
 551         unsigned int mask = 0;
 552
 553         if (filp->f_mode & FMODE_READ) {
 554                 poll_wait_set_exclusive(wait);
 555                 poll_wait(filp, &stream->read_wait, wait);
 556
 557                 finalized = stream->finalized;
 558
 559                 /*
 560                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 561                  * ordering finalized load before offsets loads.
 562                  */
 563                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 564
 565                 if (finalized)
 566                         mask |= POLLHUP;
 567
 568                 if (stream->metadata_cache->metadata_written >
 569                                 stream->metadata_out)
 570                         mask |= POLLIN;
 571         }
 572
 573         return mask;
 574 }
 575
 576 static
 577 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 578                 unsigned int cmd, unsigned long arg)
 579 {
 580         struct lttng_metadata_stream *stream = filp->private_data;
 581
 582         stream->metadata_out = stream->metadata_in;
 583 }
 584
 585 static
 586 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 587                 unsigned int cmd, unsigned long arg)
 588 {
 589         int ret;
 590         struct lttng_metadata_stream *stream = filp->private_data;
 591         struct lib_ring_buffer *buf = stream->priv;
 592
 593         switch (cmd) {
 594         case RING_BUFFER_GET_NEXT_SUBBUF:
 595         {
 596                 struct lttng_metadata_stream *stream = filp->private_data;
 597                 struct lib_ring_buffer *buf = stream->priv;
 598                 struct channel *chan = buf->backend.chan;
 599
 600                 ret = lttng_metadata_output_channel(stream, chan);
 601                 if (ret > 0) {
 602                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 603                         ret = 0;
 604                 } else if (ret < 0)
 605                         goto err;
 606                 break;
 607         }
 608         case RING_BUFFER_GET_SUBBUF:
 609         {
 610                 /*
 611                  * Random access is not allowed for metadata channel.
 612                  */
 613                 return -ENOSYS;
 614         }
 615         case RING_BUFFER_FLUSH:
 616         {
 617                 struct lttng_metadata_stream *stream = filp->private_data;
 618                 struct lib_ring_buffer *buf = stream->priv;
 619                 struct channel *chan = buf->backend.chan;
 620
 621                 /*
 622                  * Before doing the actual ring buffer flush, write up to one
 623                  * packet of metadata in the ring buffer.
 624                  */
 625                 ret = lttng_metadata_output_channel(stream, chan);
 626                 if (ret < 0)
 627                         goto err;
 628                 break;
 629         }
 630         default:
 631                 break;
 632         }
 633         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 634
 635         /* Performing lib ring buffer ioctl after our own. */
 636         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 637         if (ret < 0)
 638                 goto err;
 639
 640         switch (cmd) {
 641         case RING_BUFFER_PUT_NEXT_SUBBUF:
 642         {
 643                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 644                                 cmd, arg);
 645                 break;
 646         }
 647         default:
 648                 break;
 649         }
 650 err:
 651         return ret;
 652 }
 653
 654 #ifdef CONFIG_COMPAT
 655 static
 656 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 657                 unsigned int cmd, unsigned long arg)
 658 {
 659         int ret;
 660         struct lttng_metadata_stream *stream = filp->private_data;
 661         struct lib_ring_buffer *buf = stream->priv;
 662
 663         switch (cmd) {
 664         case RING_BUFFER_GET_NEXT_SUBBUF:
 665         {
 666                 struct lttng_metadata_stream *stream = filp->private_data;
 667                 struct lib_ring_buffer *buf = stream->priv;
 668                 struct channel *chan = buf->backend.chan;
 669
 670                 ret = lttng_metadata_output_channel(stream, chan);
 671                 if (ret > 0) {
 672                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 673                         ret = 0;
 674                 } else if (ret < 0)
 675                         goto err;
 676                 break;
 677         }
 678         case RING_BUFFER_GET_SUBBUF:
 679         {
 680                 /*
 681                  * Random access is not allowed for metadata channel.
 682                  */
 683                 return -ENOSYS;
 684         }
 685         default:
 686                 break;
 687         }
 688         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 689
 690         /* Performing lib ring buffer ioctl after our own. */
 691         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 692         if (ret < 0)
 693                 goto err;
 694
 695         switch (cmd) {
 696         case RING_BUFFER_PUT_NEXT_SUBBUF:
 697         {
 698                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 699                                 cmd, arg);
 700                 break;
 701         }
 702         default:
 703                 break;
 704         }
 705 err:
 706         return ret;
 707 }
 708 #endif
 709
 710 /*
 711  * This is not used by anonymous file descriptors. This code is left
 712  * there if we ever want to implement an inode with open() operation.
 713  */
 714 static
 715 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 716 {
 717         struct lttng_metadata_stream *stream = inode->i_private;
 718         struct lib_ring_buffer *buf = stream->priv;
 719
 720         file->private_data = buf;
 721         /*
 722          * Since life-time of metadata cache differs from that of
 723          * session, we need to keep our own reference on the transport.
 724          */
 725         if (!try_module_get(stream->transport->owner)) {
 726                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 727                 return -EBUSY;
 728         }
 729         return lib_ring_buffer_open(inode, file, buf);
 730 }
 731
 732 static
 733 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 734 {
 735         struct lttng_metadata_stream *stream = file->private_data;
 736         struct lib_ring_buffer *buf = stream->priv;
 737
 738         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 739         module_put(stream->transport->owner);
 740         return lib_ring_buffer_release(inode, file, buf);
 741 }
 742
 743 static
 744 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 745                 struct pipe_inode_info *pipe, size_t len,
 746                 unsigned int flags)
 747 {
 748         struct lttng_metadata_stream *stream = in->private_data;
 749         struct lib_ring_buffer *buf = stream->priv;
 750
 751         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 752                         flags, buf);
 753 }
 754
 755 static
 756 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 757                 struct vm_area_struct *vma)
 758 {
 759         struct lttng_metadata_stream *stream = filp->private_data;
 760         struct lib_ring_buffer *buf = stream->priv;
 761
 762         return lib_ring_buffer_mmap(filp, vma, buf);
 763 }
 764
 765 static
 766 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 767         .owner = THIS_MODULE,
 768         .open = lttng_metadata_ring_buffer_open,
 769         .release = lttng_metadata_ring_buffer_release,
 770         .poll = lttng_metadata_ring_buffer_poll,
 771         .splice_read = lttng_metadata_ring_buffer_splice_read,
 772         .mmap = lttng_metadata_ring_buffer_mmap,
 773         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 774         .llseek = vfs_lib_ring_buffer_no_llseek,
 775 #ifdef CONFIG_COMPAT
 776         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 777 #endif
 778 };
 779
 780 static
 781 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 782                 const struct file_operations *fops)
 783 {
 784         int stream_fd, ret;
 785         struct file *stream_file;
 786
 787         stream_fd = lttng_get_unused_fd();
 788         if (stream_fd < 0) {
 789                 ret = stream_fd;
 790                 goto fd_error;
 791         }
 792         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 793                         stream_priv, O_RDWR);
 794         if (IS_ERR(stream_file)) {
 795                 ret = PTR_ERR(stream_file);
 796                 goto file_error;
 797         }
 798         /*
 799          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 800          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 801          * file descriptor, so we set FMODE_PREAD here.
 802          */
 803         stream_file->f_mode |= FMODE_PREAD;
 804         fd_install(stream_fd, stream_file);
 805         /*
 806          * The stream holds a reference to the channel within the generic ring
 807          * buffer library, so no need to hold a refcount on the channel and
 808          * session files here.
 809          */
 810         return stream_fd;
 811
 812 file_error:
 813         put_unused_fd(stream_fd);
 814 fd_error:
 815         return ret;
 816 }
 817
 818 static
 819 int lttng_abi_open_stream(struct file *channel_file)
 820 {
 821         struct lttng_channel *channel = channel_file->private_data;
 822         struct lib_ring_buffer *buf;
 823         int ret;
 824         void *stream_priv;
 825
 826         buf = channel->ops->buffer_read_open(channel->chan);
 827         if (!buf)
 828                 return -ENOENT;
 829
 830         stream_priv = buf;
 831         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 832                         &lttng_stream_ring_buffer_file_operations);
 833         if (ret < 0)
 834                 goto fd_error;
 835
 836         return ret;
 837
 838 fd_error:
 839         channel->ops->buffer_read_close(buf);
 840         return ret;
 841 }
 842
 843 static
 844 int lttng_abi_open_metadata_stream(struct file *channel_file)
 845 {
 846         struct lttng_channel *channel = channel_file->private_data;
 847         struct lttng_session *session = channel->session;
 848         struct lib_ring_buffer *buf;
 849         int ret;
 850         struct lttng_metadata_stream *metadata_stream;
 851         void *stream_priv;
 852
 853         buf = channel->ops->buffer_read_open(channel->chan);
 854         if (!buf)
 855                 return -ENOENT;
 856
 857         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 858                         GFP_KERNEL);
 859         if (!metadata_stream) {
 860                 ret = -ENOMEM;
 861                 goto nomem;
 862         }
 863         metadata_stream->metadata_cache = session->metadata_cache;
 864         init_waitqueue_head(&metadata_stream->read_wait);
 865         metadata_stream->priv = buf;
 866         stream_priv = metadata_stream;
 867         metadata_stream->transport = channel->transport;
 868         mutex_init(&metadata_stream->lock);
 869
 870         /*
 871          * Since life-time of metadata cache differs from that of
 872          * session, we need to keep our own reference on the transport.
 873          */
 874         if (!try_module_get(metadata_stream->transport->owner)) {
 875                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 876                 ret = -EINVAL;
 877                 goto notransport;
 878         }
 879
 880         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 881                         &lttng_metadata_ring_buffer_file_operations);
 882         if (ret < 0)
 883                 goto fd_error;
 884
 885         kref_get(&session->metadata_cache->refcount);
 886         list_add(&metadata_stream->list,
 887                 &session->metadata_cache->metadata_stream);
 888         return ret;
 889
 890 fd_error:
 891         module_put(metadata_stream->transport->owner);
 892 notransport:
 893         kfree(metadata_stream);
 894 nomem:
 895         channel->ops->buffer_read_close(buf);
 896         return ret;
 897 }
 898
 899 static
 900 int lttng_abi_create_event(struct file *channel_file,
 901                            struct lttng_kernel_event *event_param)
 902 {
 903         struct lttng_channel *channel = channel_file->private_data;
 904         struct lttng_event *event;
 905         int event_fd, ret;
 906         struct file *event_file;
 907
 908         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 909         switch (event_param->instrumentation) {
 910         case LTTNG_KERNEL_KRETPROBE:
 911                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 912                 break;
 913         case LTTNG_KERNEL_KPROBE:
 914                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 915                 break;
 916         case LTTNG_KERNEL_FUNCTION:
 917                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 918                 break;
 919         default:
 920                 break;
 921         }
 922         switch (event_param->instrumentation) {
 923         default:
 924                 event_fd = lttng_get_unused_fd();
 925                 if (event_fd < 0) {
 926                         ret = event_fd;
 927                         goto fd_error;
 928                 }
 929                 event_file = anon_inode_getfile("[lttng_event]",
 930                                                 &lttng_event_fops,
 931                                                 NULL, O_RDWR);
 932                 if (IS_ERR(event_file)) {
 933                         ret = PTR_ERR(event_file);
 934                         goto file_error;
 935                 }
 936                 /*
 937                  * We tolerate no failure path after event creation. It
 938                  * will stay invariant for the rest of the session.
 939                  */
 940                 event = lttng_event_create(channel, event_param, NULL, NULL);
 941                 WARN_ON_ONCE(!event);
 942                 if (IS_ERR(event)) {
 943                         ret = PTR_ERR(event);
 944                         goto event_error;
 945                 }
 946                 event_file->private_data = event;
 947                 fd_install(event_fd, event_file);
 948                 /* The event holds a reference on the channel */
 949                 atomic_long_inc(&channel_file->f_count);
 950                 break;
 951         case LTTNG_KERNEL_SYSCALL:
 952                 ret = lttng_syscalls_register(channel, NULL);
 953                 if (ret)
 954                         goto fd_error;
 955                 event_fd = 0;
 956                 if (event_param->u.syscall.enable) {
 957                         ret = lttng_syscall_filter_enable(channel,
 958                                 event_param->name[0] == '\0' ?
 959                                         NULL : event_param->name);
 960                         if (ret)
 961                                 goto fd_error;
 962
 963                 } else {
 964                         ret = lttng_syscall_filter_disable(channel,
 965                                 event_param->name[0] == '\0' ?
 966                                         NULL : event_param->name);
 967                         if (ret)
 968                                 goto fd_error;
 969                 }
 970                 break;
 971         }
 972         return event_fd;
 973
 974 event_error:
 975         fput(event_file);
 976 file_error:
 977         put_unused_fd(event_fd);
 978 fd_error:
 979         return ret;
 980 }
 981
 982 /**
 983  *      lttng_channel_ioctl - lttng syscall through ioctl
 984  *
 985  *      @file: the file
 986  *      @cmd: the command
 987  *      @arg: command arg
 988  *
 989  *      This ioctl implements lttng commands:
 990  *      LTTNG_KERNEL_STREAM
 991  *              Returns an event stream file descriptor or failure.
 992  *              (typically, one event stream records events from one CPU)
 993  *      LTTNG_KERNEL_EVENT
 994  *              Returns an event file descriptor or failure.
 995  *      LTTNG_KERNEL_CONTEXT
 996  *              Prepend a context field to each event in the channel
 997  *      LTTNG_KERNEL_ENABLE
 998  *              Enable recording for events in this channel (weak enable)
 999  *      LTTNG_KERNEL_DISABLE
1000  *              Disable recording for events in this channel (strong disable)
1001  *
1002  * Channel and event file descriptors also hold a reference on the session.
1003  */
1004 static
1005 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1006 {
1007         struct lttng_channel *channel = file->private_data;
1008
1009         switch (cmd) {
1010         case LTTNG_KERNEL_OLD_STREAM:
1011         case LTTNG_KERNEL_STREAM:
1012                 return lttng_abi_open_stream(file);
1013         case LTTNG_KERNEL_OLD_EVENT:
1014         {
1015                 struct lttng_kernel_event *uevent_param;
1016                 struct lttng_kernel_old_event *old_uevent_param;
1017                 int ret;
1018
1019                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1020                                 GFP_KERNEL);
1021                 if (!uevent_param) {
1022                         ret = -ENOMEM;
1023                         goto old_event_end;
1024                 }
1025                 old_uevent_param = kmalloc(
1026                                 sizeof(struct lttng_kernel_old_event),
1027                                 GFP_KERNEL);
1028                 if (!old_uevent_param) {
1029                         ret = -ENOMEM;
1030                         goto old_event_error_free_param;
1031                 }
1032                 if (copy_from_user(old_uevent_param,
1033                                 (struct lttng_kernel_old_event __user *) arg,
1034                                 sizeof(struct lttng_kernel_old_event))) {
1035                         ret = -EFAULT;
1036                         goto old_event_error_free_old_param;
1037                 }
1038
1039                 memcpy(uevent_param->name, old_uevent_param->name,
1040                                 sizeof(uevent_param->name));
1041                 uevent_param->instrumentation =
1042                         old_uevent_param->instrumentation;
1043
1044                 switch (old_uevent_param->instrumentation) {
1045                 case LTTNG_KERNEL_KPROBE:
1046                         uevent_param->u.kprobe.addr =
1047                                 old_uevent_param->u.kprobe.addr;
1048                         uevent_param->u.kprobe.offset =
1049                                 old_uevent_param->u.kprobe.offset;
1050                         memcpy(uevent_param->u.kprobe.symbol_name,
1051                                 old_uevent_param->u.kprobe.symbol_name,
1052                                 sizeof(uevent_param->u.kprobe.symbol_name));
1053                         break;
1054                 case LTTNG_KERNEL_KRETPROBE:
1055                         uevent_param->u.kretprobe.addr =
1056                                 old_uevent_param->u.kretprobe.addr;
1057                         uevent_param->u.kretprobe.offset =
1058                                 old_uevent_param->u.kretprobe.offset;
1059                         memcpy(uevent_param->u.kretprobe.symbol_name,
1060                                 old_uevent_param->u.kretprobe.symbol_name,
1061                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1062                         break;
1063                 case LTTNG_KERNEL_FUNCTION:
1064                         memcpy(uevent_param->u.ftrace.symbol_name,
1065                                         old_uevent_param->u.ftrace.symbol_name,
1066                                         sizeof(uevent_param->u.ftrace.symbol_name));
1067                         break;
1068                 default:
1069                         break;
1070                 }
1071                 ret = lttng_abi_create_event(file, uevent_param);
1072
1073 old_event_error_free_old_param:
1074                 kfree(old_uevent_param);
1075 old_event_error_free_param:
1076                 kfree(uevent_param);
1077 old_event_end:
1078                 return ret;
1079         }
1080         case LTTNG_KERNEL_EVENT:
1081         {
1082                 struct lttng_kernel_event uevent_param;
1083
1084                 if (copy_from_user(&uevent_param,
1085                                 (struct lttng_kernel_event __user *) arg,
1086                                 sizeof(uevent_param)))
1087                         return -EFAULT;
1088                 return lttng_abi_create_event(file, &uevent_param);
1089         }
1090         case LTTNG_KERNEL_OLD_CONTEXT:
1091         {
1092                 struct lttng_kernel_context *ucontext_param;
1093                 struct lttng_kernel_old_context *old_ucontext_param;
1094                 int ret;
1095
1096                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1097                                 GFP_KERNEL);
1098                 if (!ucontext_param) {
1099                         ret = -ENOMEM;
1100                         goto old_ctx_end;
1101                 }
1102                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1103                                 GFP_KERNEL);
1104                 if (!old_ucontext_param) {
1105                         ret = -ENOMEM;
1106                         goto old_ctx_error_free_param;
1107                 }
1108
1109                 if (copy_from_user(old_ucontext_param,
1110                                 (struct lttng_kernel_old_context __user *) arg,
1111                                 sizeof(struct lttng_kernel_old_context))) {
1112                         ret = -EFAULT;
1113                         goto old_ctx_error_free_old_param;
1114                 }
1115                 ucontext_param->ctx = old_ucontext_param->ctx;
1116                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1117                                 sizeof(ucontext_param->padding));
1118                 /* only type that uses the union */
1119                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1120                         ucontext_param->u.perf_counter.type =
1121                                 old_ucontext_param->u.perf_counter.type;
1122                         ucontext_param->u.perf_counter.config =
1123                                 old_ucontext_param->u.perf_counter.config;
1124                         memcpy(ucontext_param->u.perf_counter.name,
1125                                 old_ucontext_param->u.perf_counter.name,
1126                                 sizeof(ucontext_param->u.perf_counter.name));
1127                 }
1128
1129                 ret = lttng_abi_add_context(file,
1130                                 ucontext_param,
1131                                 &channel->ctx, channel->session);
1132
1133 old_ctx_error_free_old_param:
1134                 kfree(old_ucontext_param);
1135 old_ctx_error_free_param:
1136                 kfree(ucontext_param);
1137 old_ctx_end:
1138                 return ret;
1139         }
1140         case LTTNG_KERNEL_CONTEXT:
1141         {
1142                 struct lttng_kernel_context ucontext_param;
1143
1144                 if (copy_from_user(&ucontext_param,
1145                                 (struct lttng_kernel_context __user *) arg,
1146                                 sizeof(ucontext_param)))
1147                         return -EFAULT;
1148                 return lttng_abi_add_context(file,
1149                                 &ucontext_param,
1150                                 &channel->ctx, channel->session);
1151         }
1152         case LTTNG_KERNEL_OLD_ENABLE:
1153         case LTTNG_KERNEL_ENABLE:
1154                 return lttng_channel_enable(channel);
1155         case LTTNG_KERNEL_OLD_DISABLE:
1156         case LTTNG_KERNEL_DISABLE:
1157                 return lttng_channel_disable(channel);
1158         case LTTNG_KERNEL_SYSCALL_MASK:
1159                 return lttng_channel_syscall_mask(channel,
1160                         (struct lttng_kernel_syscall_mask __user *) arg);
1161         default:
1162                 return -ENOIOCTLCMD;
1163         }
1164
1165 }
1166
1167 /**
1168  *      lttng_metadata_ioctl - lttng syscall through ioctl
1169  *
1170  *      @file: the file
1171  *      @cmd: the command
1172  *      @arg: command arg
1173  *
1174  *      This ioctl implements lttng commands:
1175  *      LTTNG_KERNEL_STREAM
1176  *              Returns an event stream file descriptor or failure.
1177  *
1178  * Channel and event file descriptors also hold a reference on the session.
1179  */
1180 static
1181 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1182 {
1183         switch (cmd) {
1184         case LTTNG_KERNEL_OLD_STREAM:
1185         case LTTNG_KERNEL_STREAM:
1186                 return lttng_abi_open_metadata_stream(file);
1187         default:
1188                 return -ENOIOCTLCMD;
1189         }
1190 }
1191
1192 /**
1193  *      lttng_channel_poll - lttng stream addition/removal monitoring
1194  *
1195  *      @file: the file
1196  *      @wait: poll table
1197  */
1198 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1199 {
1200         struct lttng_channel *channel = file->private_data;
1201         unsigned int mask = 0;
1202
1203         if (file->f_mode & FMODE_READ) {
1204                 poll_wait_set_exclusive(wait);
1205                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1206                           wait);
1207
1208                 if (channel->ops->is_disabled(channel->chan))
1209                         return POLLERR;
1210                 if (channel->ops->is_finalized(channel->chan))
1211                         return POLLHUP;
1212                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1213                         return POLLIN | POLLRDNORM;
1214                 return 0;
1215         }
1216         return mask;
1217
1218 }
1219
1220 static
1221 int lttng_channel_release(struct inode *inode, struct file *file)
1222 {
1223         struct lttng_channel *channel = file->private_data;
1224
1225         if (channel)
1226                 fput(channel->session->file);
1227         return 0;
1228 }
1229
1230 static
1231 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1232 {
1233         struct lttng_channel *channel = file->private_data;
1234
1235         if (channel) {
1236                 lttng_metadata_channel_destroy(channel);
1237                 fput(channel->session->file);
1238         }
1239
1240         return 0;
1241 }
1242
1243 static const struct file_operations lttng_channel_fops = {
1244         .owner = THIS_MODULE,
1245         .release = lttng_channel_release,
1246         .poll = lttng_channel_poll,
1247         .unlocked_ioctl = lttng_channel_ioctl,
1248 #ifdef CONFIG_COMPAT
1249         .compat_ioctl = lttng_channel_ioctl,
1250 #endif
1251 };
1252
1253 static const struct file_operations lttng_metadata_fops = {
1254         .owner = THIS_MODULE,
1255         .release = lttng_metadata_channel_release,
1256         .unlocked_ioctl = lttng_metadata_ioctl,
1257 #ifdef CONFIG_COMPAT
1258         .compat_ioctl = lttng_metadata_ioctl,
1259 #endif
1260 };
1261
1262 /**
1263  *      lttng_event_ioctl - lttng syscall through ioctl
1264  *
1265  *      @file: the file
1266  *      @cmd: the command
1267  *      @arg: command arg
1268  *
1269  *      This ioctl implements lttng commands:
1270  *      LTTNG_KERNEL_CONTEXT
1271  *              Prepend a context field to each record of this event
1272  *      LTTNG_KERNEL_ENABLE
1273  *              Enable recording for this event (weak enable)
1274  *      LTTNG_KERNEL_DISABLE
1275  *              Disable recording for this event (strong disable)
1276  */
1277 static
1278 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1279 {
1280         struct lttng_event *event = file->private_data;
1281
1282         switch (cmd) {
1283         case LTTNG_KERNEL_OLD_CONTEXT:
1284         {
1285                 struct lttng_kernel_context *ucontext_param;
1286                 struct lttng_kernel_old_context *old_ucontext_param;
1287                 int ret;
1288
1289                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1290                                 GFP_KERNEL);
1291                 if (!ucontext_param) {
1292                         ret = -ENOMEM;
1293                         goto old_ctx_end;
1294                 }
1295                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1296                                 GFP_KERNEL);
1297                 if (!old_ucontext_param) {
1298                         ret = -ENOMEM;
1299                         goto old_ctx_error_free_param;
1300                 }
1301
1302                 if (copy_from_user(old_ucontext_param,
1303                                         (struct lttng_kernel_old_context __user *) arg,
1304                                         sizeof(struct lttng_kernel_old_context))) {
1305                         ret = -EFAULT;
1306                         goto old_ctx_error_free_old_param;
1307                 }
1308                 ucontext_param->ctx = old_ucontext_param->ctx;
1309                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1310                                 sizeof(ucontext_param->padding));
1311                 /* only type that uses the union */
1312                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1313                         ucontext_param->u.perf_counter.type =
1314                                 old_ucontext_param->u.perf_counter.type;
1315                         ucontext_param->u.perf_counter.config =
1316                                 old_ucontext_param->u.perf_counter.config;
1317                         memcpy(ucontext_param->u.perf_counter.name,
1318                                         old_ucontext_param->u.perf_counter.name,
1319                                         sizeof(ucontext_param->u.perf_counter.name));
1320                 }
1321
1322                 ret = lttng_abi_add_context(file,
1323                                 ucontext_param,
1324                                 &event->ctx, event->chan->session);
1325
1326 old_ctx_error_free_old_param:
1327                 kfree(old_ucontext_param);
1328 old_ctx_error_free_param:
1329                 kfree(ucontext_param);
1330 old_ctx_end:
1331                 return ret;
1332         }
1333         case LTTNG_KERNEL_CONTEXT:
1334         {
1335                 struct lttng_kernel_context ucontext_param;
1336
1337                 if (copy_from_user(&ucontext_param,
1338                                         (struct lttng_kernel_context __user *) arg,
1339                                         sizeof(ucontext_param)))
1340                         return -EFAULT;
1341                 return lttng_abi_add_context(file,
1342                                 &ucontext_param,
1343                                 &event->ctx, event->chan->session);
1344         }
1345         case LTTNG_KERNEL_OLD_ENABLE:
1346         case LTTNG_KERNEL_ENABLE:
1347                 return lttng_event_enable(event);
1348         case LTTNG_KERNEL_OLD_DISABLE:
1349         case LTTNG_KERNEL_DISABLE:
1350                 return lttng_event_disable(event);
1351         default:
1352                 return -ENOIOCTLCMD;
1353         }
1354 }
1355
1356 static
1357 int lttng_event_release(struct inode *inode, struct file *file)
1358 {
1359         struct lttng_event *event = file->private_data;
1360
1361         if (event)
1362                 fput(event->chan->file);
1363         return 0;
1364 }
1365
1366 /* TODO: filter control ioctl */
1367 static const struct file_operations lttng_event_fops = {
1368         .owner = THIS_MODULE,
1369         .release = lttng_event_release,
1370         .unlocked_ioctl = lttng_event_ioctl,
1371 #ifdef CONFIG_COMPAT
1372         .compat_ioctl = lttng_event_ioctl,
1373 #endif
1374 };
1375
1376 static int put_u64(uint64_t val, unsigned long arg)
1377 {
1378         return put_user(val, (uint64_t __user *) arg);
1379 }
1380
1381 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1382                 unsigned int cmd, unsigned long arg)
1383 {
1384         struct lib_ring_buffer *buf = filp->private_data;
1385         struct channel *chan = buf->backend.chan;
1386         const struct lib_ring_buffer_config *config = &chan->backend.config;
1387         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1388         int ret;
1389
1390         if (atomic_read(&chan->record_disabled))
1391                 return -EIO;
1392
1393         switch (cmd) {
1394         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1395         {
1396                 uint64_t ts;
1397
1398                 ret = ops->timestamp_begin(config, buf, &ts);
1399                 if (ret < 0)
1400                         goto error;
1401                 return put_u64(ts, arg);
1402         }
1403         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1404         {
1405                 uint64_t ts;
1406
1407                 ret = ops->timestamp_end(config, buf, &ts);
1408                 if (ret < 0)
1409                         goto error;
1410                 return put_u64(ts, arg);
1411         }
1412         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1413         {
1414                 uint64_t ed;
1415
1416                 ret = ops->events_discarded(config, buf, &ed);
1417                 if (ret < 0)
1418                         goto error;
1419                 return put_u64(ed, arg);
1420         }
1421         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1422         {
1423                 uint64_t cs;
1424
1425                 ret = ops->content_size(config, buf, &cs);
1426                 if (ret < 0)
1427                         goto error;
1428                 return put_u64(cs, arg);
1429         }
1430         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1431         {
1432                 uint64_t ps;
1433
1434                 ret = ops->packet_size(config, buf, &ps);
1435                 if (ret < 0)
1436                         goto error;
1437                 return put_u64(ps, arg);
1438         }
1439         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1440         {
1441                 uint64_t si;
1442
1443                 ret = ops->stream_id(config, buf, &si);
1444                 if (ret < 0)
1445                         goto error;
1446                 return put_u64(si, arg);
1447         }
1448         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1449         {
1450                 uint64_t ts;
1451
1452                 ret = ops->current_timestamp(config, buf, &ts);
1453                 if (ret < 0)
1454                         goto error;
1455                 return put_u64(ts, arg);
1456         }
1457         default:
1458                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1459                                 cmd, arg);
1460         }
1461
1462 error:
1463         return -ENOSYS;
1464 }
1465
1466 #ifdef CONFIG_COMPAT
1467 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1468                 unsigned int cmd, unsigned long arg)
1469 {
1470         struct lib_ring_buffer *buf = filp->private_data;
1471         struct channel *chan = buf->backend.chan;
1472         const struct lib_ring_buffer_config *config = &chan->backend.config;
1473         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1474         int ret;
1475
1476         if (atomic_read(&chan->record_disabled))
1477                 return -EIO;
1478
1479         switch (cmd) {
1480         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1481         {
1482                 uint64_t ts;
1483
1484                 ret = ops->timestamp_begin(config, buf, &ts);
1485                 if (ret < 0)
1486                         goto error;
1487                 return put_u64(ts, arg);
1488         }
1489         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1490         {
1491                 uint64_t ts;
1492
1493                 ret = ops->timestamp_end(config, buf, &ts);
1494                 if (ret < 0)
1495                         goto error;
1496                 return put_u64(ts, arg);
1497         }
1498         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1499         {
1500                 uint64_t ed;
1501
1502                 ret = ops->events_discarded(config, buf, &ed);
1503                 if (ret < 0)
1504                         goto error;
1505                 return put_u64(ed, arg);
1506         }
1507         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1508         {
1509                 uint64_t cs;
1510
1511                 ret = ops->content_size(config, buf, &cs);
1512                 if (ret < 0)
1513                         goto error;
1514                 return put_u64(cs, arg);
1515         }
1516         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1517         {
1518                 uint64_t ps;
1519
1520                 ret = ops->packet_size(config, buf, &ps);
1521                 if (ret < 0)
1522                         goto error;
1523                 return put_u64(ps, arg);
1524         }
1525         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1526         {
1527                 uint64_t si;
1528
1529                 ret = ops->stream_id(config, buf, &si);
1530                 if (ret < 0)
1531                         goto error;
1532                 return put_u64(si, arg);
1533         }
1534         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1535         {
1536                 uint64_t ts;
1537
1538                 ret = ops->current_timestamp(config, buf, &ts);
1539                 if (ret < 0)
1540                         goto error;
1541                 return put_u64(ts, arg);
1542         }
1543         default:
1544                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1545                                 cmd, arg);
1546         }
1547
1548 error:
1549         return -ENOSYS;
1550 }
1551 #endif /* CONFIG_COMPAT */
1552
1553 static void lttng_stream_override_ring_buffer_fops(void)
1554 {
1555         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1556         lttng_stream_ring_buffer_file_operations.open =
1557                 lib_ring_buffer_file_operations.open;
1558         lttng_stream_ring_buffer_file_operations.release =
1559                 lib_ring_buffer_file_operations.release;
1560         lttng_stream_ring_buffer_file_operations.poll =
1561                 lib_ring_buffer_file_operations.poll;
1562         lttng_stream_ring_buffer_file_operations.splice_read =
1563                 lib_ring_buffer_file_operations.splice_read;
1564         lttng_stream_ring_buffer_file_operations.mmap =
1565                 lib_ring_buffer_file_operations.mmap;
1566         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1567                 lttng_stream_ring_buffer_ioctl;
1568         lttng_stream_ring_buffer_file_operations.llseek =
1569                 lib_ring_buffer_file_operations.llseek;
1570 #ifdef CONFIG_COMPAT
1571         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1572                 lttng_stream_ring_buffer_compat_ioctl;
1573 #endif
1574 }
1575
1576 int __init lttng_abi_init(void)
1577 {
1578         int ret = 0;
1579
1580         wrapper_vmalloc_sync_all();
1581         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1582                                         &lttng_fops, NULL);
1583
1584         if (!lttng_proc_dentry) {
1585                 printk(KERN_ERR "Error creating LTTng control file\n");
1586                 ret = -ENOMEM;
1587                 goto error;
1588         }
1589         lttng_stream_override_ring_buffer_fops();
1590
1591 error:
1592         return ret;
1593 }
1594
1595 /* No __exit annotation because used by init error path too. */
1596 void lttng_abi_exit(void)
1597 {
1598         if (lttng_proc_dentry)
1599                 remove_proc_entry("lttng", NULL);
1600 }