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                 mutex_lock(&stream->metadata_cache->lock);
 569                 if (stream->metadata_cache->metadata_written >
 570                                 stream->metadata_out)
 571                         mask |= POLLIN;
 572                 mutex_unlock(&stream->metadata_cache->lock);
 573         }
 574
 575         return mask;
 576 }
 577
 578 static
 579 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 580                 unsigned int cmd, unsigned long arg)
 581 {
 582         struct lttng_metadata_stream *stream = filp->private_data;
 583
 584         stream->metadata_out = stream->metadata_in;
 585 }
 586
 587 static
 588 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 589                 unsigned int cmd, unsigned long arg)
 590 {
 591         int ret;
 592         struct lttng_metadata_stream *stream = filp->private_data;
 593         struct lib_ring_buffer *buf = stream->priv;
 594
 595         switch (cmd) {
 596         case RING_BUFFER_GET_NEXT_SUBBUF:
 597         {
 598                 struct lttng_metadata_stream *stream = filp->private_data;
 599                 struct lib_ring_buffer *buf = stream->priv;
 600                 struct channel *chan = buf->backend.chan;
 601
 602                 ret = lttng_metadata_output_channel(stream, chan);
 603                 if (ret > 0) {
 604                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 605                         ret = 0;
 606                 } else if (ret < 0)
 607                         goto err;
 608                 break;
 609         }
 610         case RING_BUFFER_GET_SUBBUF:
 611         {
 612                 /*
 613                  * Random access is not allowed for metadata channel.
 614                  */
 615                 return -ENOSYS;
 616         }
 617         case RING_BUFFER_FLUSH:
 618         {
 619                 struct lttng_metadata_stream *stream = filp->private_data;
 620                 struct lib_ring_buffer *buf = stream->priv;
 621                 struct channel *chan = buf->backend.chan;
 622
 623                 /*
 624                  * Before doing the actual ring buffer flush, write up to one
 625                  * packet of metadata in the ring buffer.
 626                  */
 627                 ret = lttng_metadata_output_channel(stream, chan);
 628                 if (ret < 0)
 629                         goto err;
 630                 break;
 631         }
 632         default:
 633                 break;
 634         }
 635         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 636
 637         /* Performing lib ring buffer ioctl after our own. */
 638         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 639         if (ret < 0)
 640                 goto err;
 641
 642         switch (cmd) {
 643         case RING_BUFFER_PUT_NEXT_SUBBUF:
 644         {
 645                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 646                                 cmd, arg);
 647                 break;
 648         }
 649         default:
 650                 break;
 651         }
 652 err:
 653         return ret;
 654 }
 655
 656 #ifdef CONFIG_COMPAT
 657 static
 658 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 659                 unsigned int cmd, unsigned long arg)
 660 {
 661         int ret;
 662         struct lttng_metadata_stream *stream = filp->private_data;
 663         struct lib_ring_buffer *buf = stream->priv;
 664
 665         switch (cmd) {
 666         case RING_BUFFER_GET_NEXT_SUBBUF:
 667         {
 668                 struct lttng_metadata_stream *stream = filp->private_data;
 669                 struct lib_ring_buffer *buf = stream->priv;
 670                 struct channel *chan = buf->backend.chan;
 671
 672                 ret = lttng_metadata_output_channel(stream, chan);
 673                 if (ret > 0) {
 674                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 675                         ret = 0;
 676                 } else if (ret < 0)
 677                         goto err;
 678                 break;
 679         }
 680         case RING_BUFFER_GET_SUBBUF:
 681         {
 682                 /*
 683                  * Random access is not allowed for metadata channel.
 684                  */
 685                 return -ENOSYS;
 686         }
 687         default:
 688                 break;
 689         }
 690         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 691
 692         /* Performing lib ring buffer ioctl after our own. */
 693         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 694         if (ret < 0)
 695                 goto err;
 696
 697         switch (cmd) {
 698         case RING_BUFFER_PUT_NEXT_SUBBUF:
 699         {
 700                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 701                                 cmd, arg);
 702                 break;
 703         }
 704         default:
 705                 break;
 706         }
 707 err:
 708         return ret;
 709 }
 710 #endif
 711
 712 /*
 713  * This is not used by anonymous file descriptors. This code is left
 714  * there if we ever want to implement an inode with open() operation.
 715  */
 716 static
 717 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 718 {
 719         struct lttng_metadata_stream *stream = inode->i_private;
 720         struct lib_ring_buffer *buf = stream->priv;
 721
 722         file->private_data = buf;
 723         /*
 724          * Since life-time of metadata cache differs from that of
 725          * session, we need to keep our own reference on the transport.
 726          */
 727         if (!try_module_get(stream->transport->owner)) {
 728                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 729                 return -EBUSY;
 730         }
 731         return lib_ring_buffer_open(inode, file, buf);
 732 }
 733
 734 static
 735 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 736 {
 737         struct lttng_metadata_stream *stream = file->private_data;
 738         struct lib_ring_buffer *buf = stream->priv;
 739
 740         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 741         module_put(stream->transport->owner);
 742         return lib_ring_buffer_release(inode, file, buf);
 743 }
 744
 745 static
 746 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 747                 struct pipe_inode_info *pipe, size_t len,
 748                 unsigned int flags)
 749 {
 750         struct lttng_metadata_stream *stream = in->private_data;
 751         struct lib_ring_buffer *buf = stream->priv;
 752
 753         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 754                         flags, buf);
 755 }
 756
 757 static
 758 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 759                 struct vm_area_struct *vma)
 760 {
 761         struct lttng_metadata_stream *stream = filp->private_data;
 762         struct lib_ring_buffer *buf = stream->priv;
 763
 764         return lib_ring_buffer_mmap(filp, vma, buf);
 765 }
 766
 767 static
 768 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 769         .owner = THIS_MODULE,
 770         .open = lttng_metadata_ring_buffer_open,
 771         .release = lttng_metadata_ring_buffer_release,
 772         .poll = lttng_metadata_ring_buffer_poll,
 773         .splice_read = lttng_metadata_ring_buffer_splice_read,
 774         .mmap = lttng_metadata_ring_buffer_mmap,
 775         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 776         .llseek = vfs_lib_ring_buffer_no_llseek,
 777 #ifdef CONFIG_COMPAT
 778         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 779 #endif
 780 };
 781
 782 static
 783 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 784                 const struct file_operations *fops)
 785 {
 786         int stream_fd, ret;
 787         struct file *stream_file;
 788
 789         stream_fd = lttng_get_unused_fd();
 790         if (stream_fd < 0) {
 791                 ret = stream_fd;
 792                 goto fd_error;
 793         }
 794         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 795                         stream_priv, O_RDWR);
 796         if (IS_ERR(stream_file)) {
 797                 ret = PTR_ERR(stream_file);
 798                 goto file_error;
 799         }
 800         /*
 801          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 802          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 803          * file descriptor, so we set FMODE_PREAD here.
 804          */
 805         stream_file->f_mode |= FMODE_PREAD;
 806         fd_install(stream_fd, stream_file);
 807         /*
 808          * The stream holds a reference to the channel within the generic ring
 809          * buffer library, so no need to hold a refcount on the channel and
 810          * session files here.
 811          */
 812         return stream_fd;
 813
 814 file_error:
 815         put_unused_fd(stream_fd);
 816 fd_error:
 817         return ret;
 818 }
 819
 820 static
 821 int lttng_abi_open_stream(struct file *channel_file)
 822 {
 823         struct lttng_channel *channel = channel_file->private_data;
 824         struct lib_ring_buffer *buf;
 825         int ret;
 826         void *stream_priv;
 827
 828         buf = channel->ops->buffer_read_open(channel->chan);
 829         if (!buf)
 830                 return -ENOENT;
 831
 832         stream_priv = buf;
 833         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 834                         &lttng_stream_ring_buffer_file_operations);
 835         if (ret < 0)
 836                 goto fd_error;
 837
 838         return ret;
 839
 840 fd_error:
 841         channel->ops->buffer_read_close(buf);
 842         return ret;
 843 }
 844
 845 static
 846 int lttng_abi_open_metadata_stream(struct file *channel_file)
 847 {
 848         struct lttng_channel *channel = channel_file->private_data;
 849         struct lttng_session *session = channel->session;
 850         struct lib_ring_buffer *buf;
 851         int ret;
 852         struct lttng_metadata_stream *metadata_stream;
 853         void *stream_priv;
 854
 855         buf = channel->ops->buffer_read_open(channel->chan);
 856         if (!buf)
 857                 return -ENOENT;
 858
 859         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 860                         GFP_KERNEL);
 861         if (!metadata_stream) {
 862                 ret = -ENOMEM;
 863                 goto nomem;
 864         }
 865         metadata_stream->metadata_cache = session->metadata_cache;
 866         init_waitqueue_head(&metadata_stream->read_wait);
 867         metadata_stream->priv = buf;
 868         stream_priv = metadata_stream;
 869         metadata_stream->transport = channel->transport;
 870
 871         /*
 872          * Since life-time of metadata cache differs from that of
 873          * session, we need to keep our own reference on the transport.
 874          */
 875         if (!try_module_get(metadata_stream->transport->owner)) {
 876                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 877                 ret = -EINVAL;
 878                 goto notransport;
 879         }
 880
 881         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 882                         &lttng_metadata_ring_buffer_file_operations);
 883         if (ret < 0)
 884                 goto fd_error;
 885
 886         kref_get(&session->metadata_cache->refcount);
 887         list_add(&metadata_stream->list,
 888                 &session->metadata_cache->metadata_stream);
 889         return ret;
 890
 891 fd_error:
 892         module_put(metadata_stream->transport->owner);
 893 notransport:
 894         kfree(metadata_stream);
 895 nomem:
 896         channel->ops->buffer_read_close(buf);
 897         return ret;
 898 }
 899
 900 static
 901 int lttng_abi_create_event(struct file *channel_file,
 902                            struct lttng_kernel_event *event_param)
 903 {
 904         struct lttng_channel *channel = channel_file->private_data;
 905         struct lttng_event *event;
 906         int event_fd, ret;
 907         struct file *event_file;
 908
 909         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 910         switch (event_param->instrumentation) {
 911         case LTTNG_KERNEL_KRETPROBE:
 912                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 913                 break;
 914         case LTTNG_KERNEL_KPROBE:
 915                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 916                 break;
 917         case LTTNG_KERNEL_FUNCTION:
 918                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 919                 break;
 920         default:
 921                 break;
 922         }
 923         switch (event_param->instrumentation) {
 924         default:
 925                 event_fd = lttng_get_unused_fd();
 926                 if (event_fd < 0) {
 927                         ret = event_fd;
 928                         goto fd_error;
 929                 }
 930                 event_file = anon_inode_getfile("[lttng_event]",
 931                                                 &lttng_event_fops,
 932                                                 NULL, O_RDWR);
 933                 if (IS_ERR(event_file)) {
 934                         ret = PTR_ERR(event_file);
 935                         goto file_error;
 936                 }
 937                 /*
 938                  * We tolerate no failure path after event creation. It
 939                  * will stay invariant for the rest of the session.
 940                  */
 941                 event = lttng_event_create(channel, event_param, NULL, NULL);
 942                 WARN_ON_ONCE(!event);
 943                 if (IS_ERR(event)) {
 944                         ret = PTR_ERR(event);
 945                         goto event_error;
 946                 }
 947                 event_file->private_data = event;
 948                 fd_install(event_fd, event_file);
 949                 /* The event holds a reference on the channel */
 950                 atomic_long_inc(&channel_file->f_count);
 951                 break;
 952         case LTTNG_KERNEL_SYSCALL:
 953                 ret = lttng_syscalls_register(channel, NULL);
 954                 if (ret)
 955                         goto fd_error;
 956                 event_fd = 0;
 957                 if (event_param->u.syscall.enable) {
 958                         ret = lttng_syscall_filter_enable(channel,
 959                                 event_param->name[0] == '\0' ?
 960                                         NULL : event_param->name);
 961                         if (ret)
 962                                 goto fd_error;
 963
 964                 } else {
 965                         ret = lttng_syscall_filter_disable(channel,
 966                                 event_param->name[0] == '\0' ?
 967                                         NULL : event_param->name);
 968                         if (ret)
 969                                 goto fd_error;
 970                 }
 971                 break;
 972         }
 973         return event_fd;
 974
 975 event_error:
 976         fput(event_file);
 977 file_error:
 978         put_unused_fd(event_fd);
 979 fd_error:
 980         return ret;
 981 }
 982
 983 /**
 984  *      lttng_channel_ioctl - lttng syscall through ioctl
 985  *
 986  *      @file: the file
 987  *      @cmd: the command
 988  *      @arg: command arg
 989  *
 990  *      This ioctl implements lttng commands:
 991  *      LTTNG_KERNEL_STREAM
 992  *              Returns an event stream file descriptor or failure.
 993  *              (typically, one event stream records events from one CPU)
 994  *      LTTNG_KERNEL_EVENT
 995  *              Returns an event file descriptor or failure.
 996  *      LTTNG_KERNEL_CONTEXT
 997  *              Prepend a context field to each event in the channel
 998  *      LTTNG_KERNEL_ENABLE
 999  *              Enable recording for events in this channel (weak enable)
1000  *      LTTNG_KERNEL_DISABLE
1001  *              Disable recording for events in this channel (strong disable)
1002  *
1003  * Channel and event file descriptors also hold a reference on the session.
1004  */
1005 static
1006 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1007 {
1008         struct lttng_channel *channel = file->private_data;
1009
1010         switch (cmd) {
1011         case LTTNG_KERNEL_OLD_STREAM:
1012         case LTTNG_KERNEL_STREAM:
1013                 return lttng_abi_open_stream(file);
1014         case LTTNG_KERNEL_OLD_EVENT:
1015         {
1016                 struct lttng_kernel_event *uevent_param;
1017                 struct lttng_kernel_old_event *old_uevent_param;
1018                 int ret;
1019
1020                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1021                                 GFP_KERNEL);
1022                 if (!uevent_param) {
1023                         ret = -ENOMEM;
1024                         goto old_event_end;
1025                 }
1026                 old_uevent_param = kmalloc(
1027                                 sizeof(struct lttng_kernel_old_event),
1028                                 GFP_KERNEL);
1029                 if (!old_uevent_param) {
1030                         ret = -ENOMEM;
1031                         goto old_event_error_free_param;
1032                 }
1033                 if (copy_from_user(old_uevent_param,
1034                                 (struct lttng_kernel_old_event __user *) arg,
1035                                 sizeof(struct lttng_kernel_old_event))) {
1036                         ret = -EFAULT;
1037                         goto old_event_error_free_old_param;
1038                 }
1039
1040                 memcpy(uevent_param->name, old_uevent_param->name,
1041                                 sizeof(uevent_param->name));
1042                 uevent_param->instrumentation =
1043                         old_uevent_param->instrumentation;
1044
1045                 switch (old_uevent_param->instrumentation) {
1046                 case LTTNG_KERNEL_KPROBE:
1047                         uevent_param->u.kprobe.addr =
1048                                 old_uevent_param->u.kprobe.addr;
1049                         uevent_param->u.kprobe.offset =
1050                                 old_uevent_param->u.kprobe.offset;
1051                         memcpy(uevent_param->u.kprobe.symbol_name,
1052                                 old_uevent_param->u.kprobe.symbol_name,
1053                                 sizeof(uevent_param->u.kprobe.symbol_name));
1054                         break;
1055                 case LTTNG_KERNEL_KRETPROBE:
1056                         uevent_param->u.kretprobe.addr =
1057                                 old_uevent_param->u.kretprobe.addr;
1058                         uevent_param->u.kretprobe.offset =
1059                                 old_uevent_param->u.kretprobe.offset;
1060                         memcpy(uevent_param->u.kretprobe.symbol_name,
1061                                 old_uevent_param->u.kretprobe.symbol_name,
1062                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1063                         break;
1064                 case LTTNG_KERNEL_FUNCTION:
1065                         memcpy(uevent_param->u.ftrace.symbol_name,
1066                                         old_uevent_param->u.ftrace.symbol_name,
1067                                         sizeof(uevent_param->u.ftrace.symbol_name));
1068                         break;
1069                 default:
1070                         break;
1071                 }
1072                 ret = lttng_abi_create_event(file, uevent_param);
1073
1074 old_event_error_free_old_param:
1075                 kfree(old_uevent_param);
1076 old_event_error_free_param:
1077                 kfree(uevent_param);
1078 old_event_end:
1079                 return ret;
1080         }
1081         case LTTNG_KERNEL_EVENT:
1082         {
1083                 struct lttng_kernel_event uevent_param;
1084
1085                 if (copy_from_user(&uevent_param,
1086                                 (struct lttng_kernel_event __user *) arg,
1087                                 sizeof(uevent_param)))
1088                         return -EFAULT;
1089                 return lttng_abi_create_event(file, &uevent_param);
1090         }
1091         case LTTNG_KERNEL_OLD_CONTEXT:
1092         {
1093                 struct lttng_kernel_context *ucontext_param;
1094                 struct lttng_kernel_old_context *old_ucontext_param;
1095                 int ret;
1096
1097                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1098                                 GFP_KERNEL);
1099                 if (!ucontext_param) {
1100                         ret = -ENOMEM;
1101                         goto old_ctx_end;
1102                 }
1103                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1104                                 GFP_KERNEL);
1105                 if (!old_ucontext_param) {
1106                         ret = -ENOMEM;
1107                         goto old_ctx_error_free_param;
1108                 }
1109
1110                 if (copy_from_user(old_ucontext_param,
1111                                 (struct lttng_kernel_old_context __user *) arg,
1112                                 sizeof(struct lttng_kernel_old_context))) {
1113                         ret = -EFAULT;
1114                         goto old_ctx_error_free_old_param;
1115                 }
1116                 ucontext_param->ctx = old_ucontext_param->ctx;
1117                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1118                                 sizeof(ucontext_param->padding));
1119                 /* only type that uses the union */
1120                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1121                         ucontext_param->u.perf_counter.type =
1122                                 old_ucontext_param->u.perf_counter.type;
1123                         ucontext_param->u.perf_counter.config =
1124                                 old_ucontext_param->u.perf_counter.config;
1125                         memcpy(ucontext_param->u.perf_counter.name,
1126                                 old_ucontext_param->u.perf_counter.name,
1127                                 sizeof(ucontext_param->u.perf_counter.name));
1128                 }
1129
1130                 ret = lttng_abi_add_context(file,
1131                                 ucontext_param,
1132                                 &channel->ctx, channel->session);
1133
1134 old_ctx_error_free_old_param:
1135                 kfree(old_ucontext_param);
1136 old_ctx_error_free_param:
1137                 kfree(ucontext_param);
1138 old_ctx_end:
1139                 return ret;
1140         }
1141         case LTTNG_KERNEL_CONTEXT:
1142         {
1143                 struct lttng_kernel_context ucontext_param;
1144
1145                 if (copy_from_user(&ucontext_param,
1146                                 (struct lttng_kernel_context __user *) arg,
1147                                 sizeof(ucontext_param)))
1148                         return -EFAULT;
1149                 return lttng_abi_add_context(file,
1150                                 &ucontext_param,
1151                                 &channel->ctx, channel->session);
1152         }
1153         case LTTNG_KERNEL_OLD_ENABLE:
1154         case LTTNG_KERNEL_ENABLE:
1155                 return lttng_channel_enable(channel);
1156         case LTTNG_KERNEL_OLD_DISABLE:
1157         case LTTNG_KERNEL_DISABLE:
1158                 return lttng_channel_disable(channel);
1159         case LTTNG_KERNEL_SYSCALL_MASK:
1160                 return lttng_channel_syscall_mask(channel,
1161                         (struct lttng_kernel_syscall_mask __user *) arg);
1162         default:
1163                 return -ENOIOCTLCMD;
1164         }
1165
1166 }
1167
1168 /**
1169  *      lttng_metadata_ioctl - lttng syscall through ioctl
1170  *
1171  *      @file: the file
1172  *      @cmd: the command
1173  *      @arg: command arg
1174  *
1175  *      This ioctl implements lttng commands:
1176  *      LTTNG_KERNEL_STREAM
1177  *              Returns an event stream file descriptor or failure.
1178  *
1179  * Channel and event file descriptors also hold a reference on the session.
1180  */
1181 static
1182 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1183 {
1184         switch (cmd) {
1185         case LTTNG_KERNEL_OLD_STREAM:
1186         case LTTNG_KERNEL_STREAM:
1187                 return lttng_abi_open_metadata_stream(file);
1188         default:
1189                 return -ENOIOCTLCMD;
1190         }
1191 }
1192
1193 /**
1194  *      lttng_channel_poll - lttng stream addition/removal monitoring
1195  *
1196  *      @file: the file
1197  *      @wait: poll table
1198  */
1199 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1200 {
1201         struct lttng_channel *channel = file->private_data;
1202         unsigned int mask = 0;
1203
1204         if (file->f_mode & FMODE_READ) {
1205                 poll_wait_set_exclusive(wait);
1206                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1207                           wait);
1208
1209                 if (channel->ops->is_disabled(channel->chan))
1210                         return POLLERR;
1211                 if (channel->ops->is_finalized(channel->chan))
1212                         return POLLHUP;
1213                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1214                         return POLLIN | POLLRDNORM;
1215                 return 0;
1216         }
1217         return mask;
1218
1219 }
1220
1221 static
1222 int lttng_channel_release(struct inode *inode, struct file *file)
1223 {
1224         struct lttng_channel *channel = file->private_data;
1225
1226         if (channel)
1227                 fput(channel->session->file);
1228         return 0;
1229 }
1230
1231 static
1232 int lttng_metadata_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                 lttng_metadata_channel_destroy(channel);
1239         }
1240
1241         return 0;
1242 }
1243
1244 static const struct file_operations lttng_channel_fops = {
1245         .owner = THIS_MODULE,
1246         .release = lttng_channel_release,
1247         .poll = lttng_channel_poll,
1248         .unlocked_ioctl = lttng_channel_ioctl,
1249 #ifdef CONFIG_COMPAT
1250         .compat_ioctl = lttng_channel_ioctl,
1251 #endif
1252 };
1253
1254 static const struct file_operations lttng_metadata_fops = {
1255         .owner = THIS_MODULE,
1256         .release = lttng_metadata_channel_release,
1257         .unlocked_ioctl = lttng_metadata_ioctl,
1258 #ifdef CONFIG_COMPAT
1259         .compat_ioctl = lttng_metadata_ioctl,
1260 #endif
1261 };
1262
1263 /**
1264  *      lttng_event_ioctl - lttng syscall through ioctl
1265  *
1266  *      @file: the file
1267  *      @cmd: the command
1268  *      @arg: command arg
1269  *
1270  *      This ioctl implements lttng commands:
1271  *      LTTNG_KERNEL_CONTEXT
1272  *              Prepend a context field to each record of this event
1273  *      LTTNG_KERNEL_ENABLE
1274  *              Enable recording for this event (weak enable)
1275  *      LTTNG_KERNEL_DISABLE
1276  *              Disable recording for this event (strong disable)
1277  */
1278 static
1279 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1280 {
1281         struct lttng_event *event = file->private_data;
1282
1283         switch (cmd) {
1284         case LTTNG_KERNEL_OLD_CONTEXT:
1285         {
1286                 struct lttng_kernel_context *ucontext_param;
1287                 struct lttng_kernel_old_context *old_ucontext_param;
1288                 int ret;
1289
1290                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1291                                 GFP_KERNEL);
1292                 if (!ucontext_param) {
1293                         ret = -ENOMEM;
1294                         goto old_ctx_end;
1295                 }
1296                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1297                                 GFP_KERNEL);
1298                 if (!old_ucontext_param) {
1299                         ret = -ENOMEM;
1300                         goto old_ctx_error_free_param;
1301                 }
1302
1303                 if (copy_from_user(old_ucontext_param,
1304                                         (struct lttng_kernel_old_context __user *) arg,
1305                                         sizeof(struct lttng_kernel_old_context))) {
1306                         ret = -EFAULT;
1307                         goto old_ctx_error_free_old_param;
1308                 }
1309                 ucontext_param->ctx = old_ucontext_param->ctx;
1310                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1311                                 sizeof(ucontext_param->padding));
1312                 /* only type that uses the union */
1313                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1314                         ucontext_param->u.perf_counter.type =
1315                                 old_ucontext_param->u.perf_counter.type;
1316                         ucontext_param->u.perf_counter.config =
1317                                 old_ucontext_param->u.perf_counter.config;
1318                         memcpy(ucontext_param->u.perf_counter.name,
1319                                         old_ucontext_param->u.perf_counter.name,
1320                                         sizeof(ucontext_param->u.perf_counter.name));
1321                 }
1322
1323                 ret = lttng_abi_add_context(file,
1324                                 ucontext_param,
1325                                 &event->ctx, event->chan->session);
1326
1327 old_ctx_error_free_old_param:
1328                 kfree(old_ucontext_param);
1329 old_ctx_error_free_param:
1330                 kfree(ucontext_param);
1331 old_ctx_end:
1332                 return ret;
1333         }
1334         case LTTNG_KERNEL_CONTEXT:
1335         {
1336                 struct lttng_kernel_context ucontext_param;
1337
1338                 if (copy_from_user(&ucontext_param,
1339                                         (struct lttng_kernel_context __user *) arg,
1340                                         sizeof(ucontext_param)))
1341                         return -EFAULT;
1342                 return lttng_abi_add_context(file,
1343                                 &ucontext_param,
1344                                 &event->ctx, event->chan->session);
1345         }
1346         case LTTNG_KERNEL_OLD_ENABLE:
1347         case LTTNG_KERNEL_ENABLE:
1348                 return lttng_event_enable(event);
1349         case LTTNG_KERNEL_OLD_DISABLE:
1350         case LTTNG_KERNEL_DISABLE:
1351                 return lttng_event_disable(event);
1352         default:
1353                 return -ENOIOCTLCMD;
1354         }
1355 }
1356
1357 static
1358 int lttng_event_release(struct inode *inode, struct file *file)
1359 {
1360         struct lttng_event *event = file->private_data;
1361
1362         if (event)
1363                 fput(event->chan->file);
1364         return 0;
1365 }
1366
1367 /* TODO: filter control ioctl */
1368 static const struct file_operations lttng_event_fops = {
1369         .owner = THIS_MODULE,
1370         .release = lttng_event_release,
1371         .unlocked_ioctl = lttng_event_ioctl,
1372 #ifdef CONFIG_COMPAT
1373         .compat_ioctl = lttng_event_ioctl,
1374 #endif
1375 };
1376
1377 static int put_u64(uint64_t val, unsigned long arg)
1378 {
1379         return put_user(val, (uint64_t __user *) arg);
1380 }
1381
1382 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1383                 unsigned int cmd, unsigned long arg)
1384 {
1385         struct lib_ring_buffer *buf = filp->private_data;
1386         struct channel *chan = buf->backend.chan;
1387         const struct lib_ring_buffer_config *config = &chan->backend.config;
1388         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1389         int ret;
1390
1391         if (atomic_read(&chan->record_disabled))
1392                 return -EIO;
1393
1394         switch (cmd) {
1395         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1396         {
1397                 uint64_t ts;
1398
1399                 ret = ops->timestamp_begin(config, buf, &ts);
1400                 if (ret < 0)
1401                         goto error;
1402                 return put_u64(ts, arg);
1403         }
1404         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1405         {
1406                 uint64_t ts;
1407
1408                 ret = ops->timestamp_end(config, buf, &ts);
1409                 if (ret < 0)
1410                         goto error;
1411                 return put_u64(ts, arg);
1412         }
1413         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1414         {
1415                 uint64_t ed;
1416
1417                 ret = ops->events_discarded(config, buf, &ed);
1418                 if (ret < 0)
1419                         goto error;
1420                 return put_u64(ed, arg);
1421         }
1422         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1423         {
1424                 uint64_t cs;
1425
1426                 ret = ops->content_size(config, buf, &cs);
1427                 if (ret < 0)
1428                         goto error;
1429                 return put_u64(cs, arg);
1430         }
1431         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1432         {
1433                 uint64_t ps;
1434
1435                 ret = ops->packet_size(config, buf, &ps);
1436                 if (ret < 0)
1437                         goto error;
1438                 return put_u64(ps, arg);
1439         }
1440         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1441         {
1442                 uint64_t si;
1443
1444                 ret = ops->stream_id(config, buf, &si);
1445                 if (ret < 0)
1446                         goto error;
1447                 return put_u64(si, arg);
1448         }
1449         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1450         {
1451                 uint64_t ts;
1452
1453                 ret = ops->current_timestamp(config, buf, &ts);
1454                 if (ret < 0)
1455                         goto error;
1456                 return put_u64(ts, arg);
1457         }
1458         default:
1459                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1460                                 cmd, arg);
1461         }
1462
1463 error:
1464         return -ENOSYS;
1465 }
1466
1467 #ifdef CONFIG_COMPAT
1468 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1469                 unsigned int cmd, unsigned long arg)
1470 {
1471         struct lib_ring_buffer *buf = filp->private_data;
1472         struct channel *chan = buf->backend.chan;
1473         const struct lib_ring_buffer_config *config = &chan->backend.config;
1474         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1475         int ret;
1476
1477         if (atomic_read(&chan->record_disabled))
1478                 return -EIO;
1479
1480         switch (cmd) {
1481         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1482         {
1483                 uint64_t ts;
1484
1485                 ret = ops->timestamp_begin(config, buf, &ts);
1486                 if (ret < 0)
1487                         goto error;
1488                 return put_u64(ts, arg);
1489         }
1490         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1491         {
1492                 uint64_t ts;
1493
1494                 ret = ops->timestamp_end(config, buf, &ts);
1495                 if (ret < 0)
1496                         goto error;
1497                 return put_u64(ts, arg);
1498         }
1499         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1500         {
1501                 uint64_t ed;
1502
1503                 ret = ops->events_discarded(config, buf, &ed);
1504                 if (ret < 0)
1505                         goto error;
1506                 return put_u64(ed, arg);
1507         }
1508         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1509         {
1510                 uint64_t cs;
1511
1512                 ret = ops->content_size(config, buf, &cs);
1513                 if (ret < 0)
1514                         goto error;
1515                 return put_u64(cs, arg);
1516         }
1517         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1518         {
1519                 uint64_t ps;
1520
1521                 ret = ops->packet_size(config, buf, &ps);
1522                 if (ret < 0)
1523                         goto error;
1524                 return put_u64(ps, arg);
1525         }
1526         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1527         {
1528                 uint64_t si;
1529
1530                 ret = ops->stream_id(config, buf, &si);
1531                 if (ret < 0)
1532                         goto error;
1533                 return put_u64(si, arg);
1534         }
1535         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1536         {
1537                 uint64_t ts;
1538
1539                 ret = ops->current_timestamp(config, buf, &ts);
1540                 if (ret < 0)
1541                         goto error;
1542                 return put_u64(ts, arg);
1543         }
1544         default:
1545                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1546                                 cmd, arg);
1547         }
1548
1549 error:
1550         return -ENOSYS;
1551 }
1552 #endif /* CONFIG_COMPAT */
1553
1554 static void lttng_stream_override_ring_buffer_fops(void)
1555 {
1556         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1557         lttng_stream_ring_buffer_file_operations.open =
1558                 lib_ring_buffer_file_operations.open;
1559         lttng_stream_ring_buffer_file_operations.release =
1560                 lib_ring_buffer_file_operations.release;
1561         lttng_stream_ring_buffer_file_operations.poll =
1562                 lib_ring_buffer_file_operations.poll;
1563         lttng_stream_ring_buffer_file_operations.splice_read =
1564                 lib_ring_buffer_file_operations.splice_read;
1565         lttng_stream_ring_buffer_file_operations.mmap =
1566                 lib_ring_buffer_file_operations.mmap;
1567         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1568                 lttng_stream_ring_buffer_ioctl;
1569         lttng_stream_ring_buffer_file_operations.llseek =
1570                 lib_ring_buffer_file_operations.llseek;
1571 #ifdef CONFIG_COMPAT
1572         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1573                 lttng_stream_ring_buffer_compat_ioctl;
1574 #endif
1575 }
1576
1577 int __init lttng_abi_init(void)
1578 {
1579         int ret = 0;
1580
1581         wrapper_vmalloc_sync_all();
1582         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1583                                         &lttng_fops, NULL);
1584
1585         if (!lttng_proc_dentry) {
1586                 printk(KERN_ERR "Error creating LTTng control file\n");
1587                 ret = -ENOMEM;
1588                 goto error;
1589         }
1590         lttng_stream_override_ring_buffer_fops();
1591
1592 error:
1593         return ret;
1594 }
1595
1596 /* No __exit annotation because used by init error path too. */
1597 void lttng_abi_exit(void)
1598 {
1599         if (lttng_proc_dentry)
1600                 remove_proc_entry("lttng", NULL);
1601 }