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         case RING_BUFFER_SNAPSHOT:
 633         {
 634                 /*
 635                  * Force the buffer to quiescent so the ring buffer
 636                  * don't attempt to perform a SWITCH_FLUSH, which would
 637                  * desynchronize the client accounting of the amount of
 638                  * data available in the buffer from the ring buffer
 639                  * view.
 640                  */
 641                 buf->quiescent = true;
 642                 break;
 643         }
 644         default:
 645                 break;
 646         }
 647         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 648
 649         /* Performing lib ring buffer ioctl after our own. */
 650         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 651         if (ret < 0)
 652                 goto err;
 653
 654         switch (cmd) {
 655         case RING_BUFFER_PUT_NEXT_SUBBUF:
 656         {
 657                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 658                                 cmd, arg);
 659                 break;
 660         }
 661         default:
 662                 break;
 663         }
 664 err:
 665         return ret;
 666 }
 667
 668 #ifdef CONFIG_COMPAT
 669 static
 670 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 671                 unsigned int cmd, unsigned long arg)
 672 {
 673         int ret;
 674         struct lttng_metadata_stream *stream = filp->private_data;
 675         struct lib_ring_buffer *buf = stream->priv;
 676
 677         switch (cmd) {
 678         case RING_BUFFER_GET_NEXT_SUBBUF:
 679         {
 680                 struct lttng_metadata_stream *stream = filp->private_data;
 681                 struct lib_ring_buffer *buf = stream->priv;
 682                 struct channel *chan = buf->backend.chan;
 683
 684                 ret = lttng_metadata_output_channel(stream, chan);
 685                 if (ret > 0) {
 686                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 687                         ret = 0;
 688                 } else if (ret < 0)
 689                         goto err;
 690                 break;
 691         }
 692         case RING_BUFFER_GET_SUBBUF:
 693         {
 694                 /*
 695                  * Random access is not allowed for metadata channel.
 696                  */
 697                 return -ENOSYS;
 698         }
 699         case RING_BUFFER_FLUSH:
 700         {
 701                 struct lttng_metadata_stream *stream = filp->private_data;
 702                 struct lib_ring_buffer *buf = stream->priv;
 703                 struct channel *chan = buf->backend.chan;
 704
 705                 /*
 706                  * Before doing the actual ring buffer flush, write up to one
 707                  * packet of metadata in the ring buffer.
 708                  */
 709                 ret = lttng_metadata_output_channel(stream, chan);
 710                 if (ret < 0)
 711                         goto err;
 712                 break;
 713         }
 714         case RING_BUFFER_SNAPSHOT:
 715         {
 716                 /*
 717                  * Force the buffer to quiescent so the ring buffer
 718                  * don't attempt to perform a SWITCH_FLUSH, which would
 719                  * desynchronize the client accounting of the amount of
 720                  * data available in the buffer from the ring buffer
 721                  * view.
 722                  */
 723                 buf->quiescent = true;
 724                 break;
 725         }
 726         default:
 727                 break;
 728         }
 729         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 730
 731         /* Performing lib ring buffer ioctl after our own. */
 732         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 733         if (ret < 0)
 734                 goto err;
 735
 736         switch (cmd) {
 737         case RING_BUFFER_PUT_NEXT_SUBBUF:
 738         {
 739                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 740                                 cmd, arg);
 741                 break;
 742         }
 743         default:
 744                 break;
 745         }
 746 err:
 747         return ret;
 748 }
 749 #endif
 750
 751 /*
 752  * This is not used by anonymous file descriptors. This code is left
 753  * there if we ever want to implement an inode with open() operation.
 754  */
 755 static
 756 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 757 {
 758         struct lttng_metadata_stream *stream = inode->i_private;
 759         struct lib_ring_buffer *buf = stream->priv;
 760
 761         file->private_data = buf;
 762         /*
 763          * Since life-time of metadata cache differs from that of
 764          * session, we need to keep our own reference on the transport.
 765          */
 766         if (!try_module_get(stream->transport->owner)) {
 767                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 768                 return -EBUSY;
 769         }
 770         return lib_ring_buffer_open(inode, file, buf);
 771 }
 772
 773 static
 774 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 775 {
 776         struct lttng_metadata_stream *stream = file->private_data;
 777         struct lib_ring_buffer *buf = stream->priv;
 778
 779         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 780         module_put(stream->transport->owner);
 781         return lib_ring_buffer_release(inode, file, buf);
 782 }
 783
 784 static
 785 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 786                 struct pipe_inode_info *pipe, size_t len,
 787                 unsigned int flags)
 788 {
 789         struct lttng_metadata_stream *stream = in->private_data;
 790         struct lib_ring_buffer *buf = stream->priv;
 791
 792         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 793                         flags, buf);
 794 }
 795
 796 static
 797 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 798                 struct vm_area_struct *vma)
 799 {
 800         struct lttng_metadata_stream *stream = filp->private_data;
 801         struct lib_ring_buffer *buf = stream->priv;
 802
 803         return lib_ring_buffer_mmap(filp, vma, buf);
 804 }
 805
 806 static
 807 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 808         .owner = THIS_MODULE,
 809         .open = lttng_metadata_ring_buffer_open,
 810         .release = lttng_metadata_ring_buffer_release,
 811         .poll = lttng_metadata_ring_buffer_poll,
 812         .splice_read = lttng_metadata_ring_buffer_splice_read,
 813         .mmap = lttng_metadata_ring_buffer_mmap,
 814         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 815         .llseek = vfs_lib_ring_buffer_no_llseek,
 816 #ifdef CONFIG_COMPAT
 817         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 818 #endif
 819 };
 820
 821 static
 822 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 823                 const struct file_operations *fops)
 824 {
 825         int stream_fd, ret;
 826         struct file *stream_file;
 827
 828         stream_fd = lttng_get_unused_fd();
 829         if (stream_fd < 0) {
 830                 ret = stream_fd;
 831                 goto fd_error;
 832         }
 833         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 834                         stream_priv, O_RDWR);
 835         if (IS_ERR(stream_file)) {
 836                 ret = PTR_ERR(stream_file);
 837                 goto file_error;
 838         }
 839         /*
 840          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 841          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 842          * file descriptor, so we set FMODE_PREAD here.
 843          */
 844         stream_file->f_mode |= FMODE_PREAD;
 845         fd_install(stream_fd, stream_file);
 846         /*
 847          * The stream holds a reference to the channel within the generic ring
 848          * buffer library, so no need to hold a refcount on the channel and
 849          * session files here.
 850          */
 851         return stream_fd;
 852
 853 file_error:
 854         put_unused_fd(stream_fd);
 855 fd_error:
 856         return ret;
 857 }
 858
 859 static
 860 int lttng_abi_open_stream(struct file *channel_file)
 861 {
 862         struct lttng_channel *channel = channel_file->private_data;
 863         struct lib_ring_buffer *buf;
 864         int ret;
 865         void *stream_priv;
 866
 867         buf = channel->ops->buffer_read_open(channel->chan);
 868         if (!buf)
 869                 return -ENOENT;
 870
 871         stream_priv = buf;
 872         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 873                         &lttng_stream_ring_buffer_file_operations);
 874         if (ret < 0)
 875                 goto fd_error;
 876
 877         return ret;
 878
 879 fd_error:
 880         channel->ops->buffer_read_close(buf);
 881         return ret;
 882 }
 883
 884 static
 885 int lttng_abi_open_metadata_stream(struct file *channel_file)
 886 {
 887         struct lttng_channel *channel = channel_file->private_data;
 888         struct lttng_session *session = channel->session;
 889         struct lib_ring_buffer *buf;
 890         int ret;
 891         struct lttng_metadata_stream *metadata_stream;
 892         void *stream_priv;
 893
 894         buf = channel->ops->buffer_read_open(channel->chan);
 895         if (!buf)
 896                 return -ENOENT;
 897
 898         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 899                         GFP_KERNEL);
 900         if (!metadata_stream) {
 901                 ret = -ENOMEM;
 902                 goto nomem;
 903         }
 904         metadata_stream->metadata_cache = session->metadata_cache;
 905         init_waitqueue_head(&metadata_stream->read_wait);
 906         metadata_stream->priv = buf;
 907         stream_priv = metadata_stream;
 908         metadata_stream->transport = channel->transport;
 909
 910         /*
 911          * Since life-time of metadata cache differs from that of
 912          * session, we need to keep our own reference on the transport.
 913          */
 914         if (!try_module_get(metadata_stream->transport->owner)) {
 915                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 916                 ret = -EINVAL;
 917                 goto notransport;
 918         }
 919
 920         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 921                         &lttng_metadata_ring_buffer_file_operations);
 922         if (ret < 0)
 923                 goto fd_error;
 924
 925         kref_get(&session->metadata_cache->refcount);
 926         list_add(&metadata_stream->list,
 927                 &session->metadata_cache->metadata_stream);
 928         return ret;
 929
 930 fd_error:
 931         module_put(metadata_stream->transport->owner);
 932 notransport:
 933         kfree(metadata_stream);
 934 nomem:
 935         channel->ops->buffer_read_close(buf);
 936         return ret;
 937 }
 938
 939 static
 940 int lttng_abi_create_event(struct file *channel_file,
 941                            struct lttng_kernel_event *event_param)
 942 {
 943         struct lttng_channel *channel = channel_file->private_data;
 944         struct lttng_event *event;
 945         int event_fd, ret;
 946         struct file *event_file;
 947
 948         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 949         switch (event_param->instrumentation) {
 950         case LTTNG_KERNEL_KRETPROBE:
 951                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 952                 break;
 953         case LTTNG_KERNEL_KPROBE:
 954                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 955                 break;
 956         case LTTNG_KERNEL_FUNCTION:
 957                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 958                 break;
 959         default:
 960                 break;
 961         }
 962         switch (event_param->instrumentation) {
 963         default:
 964                 event_fd = lttng_get_unused_fd();
 965                 if (event_fd < 0) {
 966                         ret = event_fd;
 967                         goto fd_error;
 968                 }
 969                 event_file = anon_inode_getfile("[lttng_event]",
 970                                                 &lttng_event_fops,
 971                                                 NULL, O_RDWR);
 972                 if (IS_ERR(event_file)) {
 973                         ret = PTR_ERR(event_file);
 974                         goto file_error;
 975                 }
 976                 /*
 977                  * We tolerate no failure path after event creation. It
 978                  * will stay invariant for the rest of the session.
 979                  */
 980                 event = lttng_event_create(channel, event_param, NULL, NULL);
 981                 WARN_ON_ONCE(!event);
 982                 if (IS_ERR(event)) {
 983                         ret = PTR_ERR(event);
 984                         goto event_error;
 985                 }
 986                 event_file->private_data = event;
 987                 fd_install(event_fd, event_file);
 988                 /* The event holds a reference on the channel */
 989                 atomic_long_inc(&channel_file->f_count);
 990                 break;
 991         case LTTNG_KERNEL_SYSCALL:
 992                 ret = lttng_syscalls_register(channel, NULL);
 993                 if (ret)
 994                         goto fd_error;
 995                 event_fd = 0;
 996                 if (event_param->u.syscall.enable) {
 997                         ret = lttng_syscall_filter_enable(channel,
 998                                 event_param->name[0] == '\0' ?
 999                                         NULL : event_param->name);
1000                         if (ret)
1001                                 goto fd_error;
1002
1003                 } else {
1004                         ret = lttng_syscall_filter_disable(channel,
1005                                 event_param->name[0] == '\0' ?
1006                                         NULL : event_param->name);
1007                         if (ret)
1008                                 goto fd_error;
1009                 }
1010                 break;
1011         }
1012         return event_fd;
1013
1014 event_error:
1015         fput(event_file);
1016 file_error:
1017         put_unused_fd(event_fd);
1018 fd_error:
1019         return ret;
1020 }
1021
1022 /**
1023  *      lttng_channel_ioctl - lttng syscall through ioctl
1024  *
1025  *      @file: the file
1026  *      @cmd: the command
1027  *      @arg: command arg
1028  *
1029  *      This ioctl implements lttng commands:
1030  *      LTTNG_KERNEL_STREAM
1031  *              Returns an event stream file descriptor or failure.
1032  *              (typically, one event stream records events from one CPU)
1033  *      LTTNG_KERNEL_EVENT
1034  *              Returns an event file descriptor or failure.
1035  *      LTTNG_KERNEL_CONTEXT
1036  *              Prepend a context field to each event in the channel
1037  *      LTTNG_KERNEL_ENABLE
1038  *              Enable recording for events in this channel (weak enable)
1039  *      LTTNG_KERNEL_DISABLE
1040  *              Disable recording for events in this channel (strong disable)
1041  *
1042  * Channel and event file descriptors also hold a reference on the session.
1043  */
1044 static
1045 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1046 {
1047         struct lttng_channel *channel = file->private_data;
1048
1049         switch (cmd) {
1050         case LTTNG_KERNEL_OLD_STREAM:
1051         case LTTNG_KERNEL_STREAM:
1052                 return lttng_abi_open_stream(file);
1053         case LTTNG_KERNEL_OLD_EVENT:
1054         {
1055                 struct lttng_kernel_event *uevent_param;
1056                 struct lttng_kernel_old_event *old_uevent_param;
1057                 int ret;
1058
1059                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1060                                 GFP_KERNEL);
1061                 if (!uevent_param) {
1062                         ret = -ENOMEM;
1063                         goto old_event_end;
1064                 }
1065                 old_uevent_param = kmalloc(
1066                                 sizeof(struct lttng_kernel_old_event),
1067                                 GFP_KERNEL);
1068                 if (!old_uevent_param) {
1069                         ret = -ENOMEM;
1070                         goto old_event_error_free_param;
1071                 }
1072                 if (copy_from_user(old_uevent_param,
1073                                 (struct lttng_kernel_old_event __user *) arg,
1074                                 sizeof(struct lttng_kernel_old_event))) {
1075                         ret = -EFAULT;
1076                         goto old_event_error_free_old_param;
1077                 }
1078
1079                 memcpy(uevent_param->name, old_uevent_param->name,
1080                                 sizeof(uevent_param->name));
1081                 uevent_param->instrumentation =
1082                         old_uevent_param->instrumentation;
1083
1084                 switch (old_uevent_param->instrumentation) {
1085                 case LTTNG_KERNEL_KPROBE:
1086                         uevent_param->u.kprobe.addr =
1087                                 old_uevent_param->u.kprobe.addr;
1088                         uevent_param->u.kprobe.offset =
1089                                 old_uevent_param->u.kprobe.offset;
1090                         memcpy(uevent_param->u.kprobe.symbol_name,
1091                                 old_uevent_param->u.kprobe.symbol_name,
1092                                 sizeof(uevent_param->u.kprobe.symbol_name));
1093                         break;
1094                 case LTTNG_KERNEL_KRETPROBE:
1095                         uevent_param->u.kretprobe.addr =
1096                                 old_uevent_param->u.kretprobe.addr;
1097                         uevent_param->u.kretprobe.offset =
1098                                 old_uevent_param->u.kretprobe.offset;
1099                         memcpy(uevent_param->u.kretprobe.symbol_name,
1100                                 old_uevent_param->u.kretprobe.symbol_name,
1101                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1102                         break;
1103                 case LTTNG_KERNEL_FUNCTION:
1104                         memcpy(uevent_param->u.ftrace.symbol_name,
1105                                         old_uevent_param->u.ftrace.symbol_name,
1106                                         sizeof(uevent_param->u.ftrace.symbol_name));
1107                         break;
1108                 default:
1109                         break;
1110                 }
1111                 ret = lttng_abi_create_event(file, uevent_param);
1112
1113 old_event_error_free_old_param:
1114                 kfree(old_uevent_param);
1115 old_event_error_free_param:
1116                 kfree(uevent_param);
1117 old_event_end:
1118                 return ret;
1119         }
1120         case LTTNG_KERNEL_EVENT:
1121         {
1122                 struct lttng_kernel_event uevent_param;
1123
1124                 if (copy_from_user(&uevent_param,
1125                                 (struct lttng_kernel_event __user *) arg,
1126                                 sizeof(uevent_param)))
1127                         return -EFAULT;
1128                 return lttng_abi_create_event(file, &uevent_param);
1129         }
1130         case LTTNG_KERNEL_OLD_CONTEXT:
1131         {
1132                 struct lttng_kernel_context *ucontext_param;
1133                 struct lttng_kernel_old_context *old_ucontext_param;
1134                 int ret;
1135
1136                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1137                                 GFP_KERNEL);
1138                 if (!ucontext_param) {
1139                         ret = -ENOMEM;
1140                         goto old_ctx_end;
1141                 }
1142                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1143                                 GFP_KERNEL);
1144                 if (!old_ucontext_param) {
1145                         ret = -ENOMEM;
1146                         goto old_ctx_error_free_param;
1147                 }
1148
1149                 if (copy_from_user(old_ucontext_param,
1150                                 (struct lttng_kernel_old_context __user *) arg,
1151                                 sizeof(struct lttng_kernel_old_context))) {
1152                         ret = -EFAULT;
1153                         goto old_ctx_error_free_old_param;
1154                 }
1155                 ucontext_param->ctx = old_ucontext_param->ctx;
1156                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1157                                 sizeof(ucontext_param->padding));
1158                 /* only type that uses the union */
1159                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1160                         ucontext_param->u.perf_counter.type =
1161                                 old_ucontext_param->u.perf_counter.type;
1162                         ucontext_param->u.perf_counter.config =
1163                                 old_ucontext_param->u.perf_counter.config;
1164                         memcpy(ucontext_param->u.perf_counter.name,
1165                                 old_ucontext_param->u.perf_counter.name,
1166                                 sizeof(ucontext_param->u.perf_counter.name));
1167                 }
1168
1169                 ret = lttng_abi_add_context(file,
1170                                 ucontext_param,
1171                                 &channel->ctx, channel->session);
1172
1173 old_ctx_error_free_old_param:
1174                 kfree(old_ucontext_param);
1175 old_ctx_error_free_param:
1176                 kfree(ucontext_param);
1177 old_ctx_end:
1178                 return ret;
1179         }
1180         case LTTNG_KERNEL_CONTEXT:
1181         {
1182                 struct lttng_kernel_context ucontext_param;
1183
1184                 if (copy_from_user(&ucontext_param,
1185                                 (struct lttng_kernel_context __user *) arg,
1186                                 sizeof(ucontext_param)))
1187                         return -EFAULT;
1188                 return lttng_abi_add_context(file,
1189                                 &ucontext_param,
1190                                 &channel->ctx, channel->session);
1191         }
1192         case LTTNG_KERNEL_OLD_ENABLE:
1193         case LTTNG_KERNEL_ENABLE:
1194                 return lttng_channel_enable(channel);
1195         case LTTNG_KERNEL_OLD_DISABLE:
1196         case LTTNG_KERNEL_DISABLE:
1197                 return lttng_channel_disable(channel);
1198         case LTTNG_KERNEL_SYSCALL_MASK:
1199                 return lttng_channel_syscall_mask(channel,
1200                         (struct lttng_kernel_syscall_mask __user *) arg);
1201         default:
1202                 return -ENOIOCTLCMD;
1203         }
1204
1205 }
1206
1207 /**
1208  *      lttng_metadata_ioctl - lttng syscall through ioctl
1209  *
1210  *      @file: the file
1211  *      @cmd: the command
1212  *      @arg: command arg
1213  *
1214  *      This ioctl implements lttng commands:
1215  *      LTTNG_KERNEL_STREAM
1216  *              Returns an event stream file descriptor or failure.
1217  *
1218  * Channel and event file descriptors also hold a reference on the session.
1219  */
1220 static
1221 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1222 {
1223         switch (cmd) {
1224         case LTTNG_KERNEL_OLD_STREAM:
1225         case LTTNG_KERNEL_STREAM:
1226                 return lttng_abi_open_metadata_stream(file);
1227         default:
1228                 return -ENOIOCTLCMD;
1229         }
1230 }
1231
1232 /**
1233  *      lttng_channel_poll - lttng stream addition/removal monitoring
1234  *
1235  *      @file: the file
1236  *      @wait: poll table
1237  */
1238 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1239 {
1240         struct lttng_channel *channel = file->private_data;
1241         unsigned int mask = 0;
1242
1243         if (file->f_mode & FMODE_READ) {
1244                 poll_wait_set_exclusive(wait);
1245                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1246                           wait);
1247
1248                 if (channel->ops->is_disabled(channel->chan))
1249                         return POLLERR;
1250                 if (channel->ops->is_finalized(channel->chan))
1251                         return POLLHUP;
1252                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1253                         return POLLIN | POLLRDNORM;
1254                 return 0;
1255         }
1256         return mask;
1257
1258 }
1259
1260 static
1261 int lttng_channel_release(struct inode *inode, struct file *file)
1262 {
1263         struct lttng_channel *channel = file->private_data;
1264
1265         if (channel)
1266                 fput(channel->session->file);
1267         return 0;
1268 }
1269
1270 static
1271 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1272 {
1273         struct lttng_channel *channel = file->private_data;
1274
1275         if (channel) {
1276                 fput(channel->session->file);
1277                 lttng_metadata_channel_destroy(channel);
1278         }
1279
1280         return 0;
1281 }
1282
1283 static const struct file_operations lttng_channel_fops = {
1284         .owner = THIS_MODULE,
1285         .release = lttng_channel_release,
1286         .poll = lttng_channel_poll,
1287         .unlocked_ioctl = lttng_channel_ioctl,
1288 #ifdef CONFIG_COMPAT
1289         .compat_ioctl = lttng_channel_ioctl,
1290 #endif
1291 };
1292
1293 static const struct file_operations lttng_metadata_fops = {
1294         .owner = THIS_MODULE,
1295         .release = lttng_metadata_channel_release,
1296         .unlocked_ioctl = lttng_metadata_ioctl,
1297 #ifdef CONFIG_COMPAT
1298         .compat_ioctl = lttng_metadata_ioctl,
1299 #endif
1300 };
1301
1302 /**
1303  *      lttng_event_ioctl - lttng syscall through ioctl
1304  *
1305  *      @file: the file
1306  *      @cmd: the command
1307  *      @arg: command arg
1308  *
1309  *      This ioctl implements lttng commands:
1310  *      LTTNG_KERNEL_CONTEXT
1311  *              Prepend a context field to each record of this event
1312  *      LTTNG_KERNEL_ENABLE
1313  *              Enable recording for this event (weak enable)
1314  *      LTTNG_KERNEL_DISABLE
1315  *              Disable recording for this event (strong disable)
1316  */
1317 static
1318 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1319 {
1320         struct lttng_event *event = file->private_data;
1321
1322         switch (cmd) {
1323         case LTTNG_KERNEL_OLD_CONTEXT:
1324         {
1325                 struct lttng_kernel_context *ucontext_param;
1326                 struct lttng_kernel_old_context *old_ucontext_param;
1327                 int ret;
1328
1329                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1330                                 GFP_KERNEL);
1331                 if (!ucontext_param) {
1332                         ret = -ENOMEM;
1333                         goto old_ctx_end;
1334                 }
1335                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1336                                 GFP_KERNEL);
1337                 if (!old_ucontext_param) {
1338                         ret = -ENOMEM;
1339                         goto old_ctx_error_free_param;
1340                 }
1341
1342                 if (copy_from_user(old_ucontext_param,
1343                                         (struct lttng_kernel_old_context __user *) arg,
1344                                         sizeof(struct lttng_kernel_old_context))) {
1345                         ret = -EFAULT;
1346                         goto old_ctx_error_free_old_param;
1347                 }
1348                 ucontext_param->ctx = old_ucontext_param->ctx;
1349                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1350                                 sizeof(ucontext_param->padding));
1351                 /* only type that uses the union */
1352                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1353                         ucontext_param->u.perf_counter.type =
1354                                 old_ucontext_param->u.perf_counter.type;
1355                         ucontext_param->u.perf_counter.config =
1356                                 old_ucontext_param->u.perf_counter.config;
1357                         memcpy(ucontext_param->u.perf_counter.name,
1358                                         old_ucontext_param->u.perf_counter.name,
1359                                         sizeof(ucontext_param->u.perf_counter.name));
1360                 }
1361
1362                 ret = lttng_abi_add_context(file,
1363                                 ucontext_param,
1364                                 &event->ctx, event->chan->session);
1365
1366 old_ctx_error_free_old_param:
1367                 kfree(old_ucontext_param);
1368 old_ctx_error_free_param:
1369                 kfree(ucontext_param);
1370 old_ctx_end:
1371                 return ret;
1372         }
1373         case LTTNG_KERNEL_CONTEXT:
1374         {
1375                 struct lttng_kernel_context ucontext_param;
1376
1377                 if (copy_from_user(&ucontext_param,
1378                                         (struct lttng_kernel_context __user *) arg,
1379                                         sizeof(ucontext_param)))
1380                         return -EFAULT;
1381                 return lttng_abi_add_context(file,
1382                                 &ucontext_param,
1383                                 &event->ctx, event->chan->session);
1384         }
1385         case LTTNG_KERNEL_OLD_ENABLE:
1386         case LTTNG_KERNEL_ENABLE:
1387                 return lttng_event_enable(event);
1388         case LTTNG_KERNEL_OLD_DISABLE:
1389         case LTTNG_KERNEL_DISABLE:
1390                 return lttng_event_disable(event);
1391         default:
1392                 return -ENOIOCTLCMD;
1393         }
1394 }
1395
1396 static
1397 int lttng_event_release(struct inode *inode, struct file *file)
1398 {
1399         struct lttng_event *event = file->private_data;
1400
1401         if (event)
1402                 fput(event->chan->file);
1403         return 0;
1404 }
1405
1406 /* TODO: filter control ioctl */
1407 static const struct file_operations lttng_event_fops = {
1408         .owner = THIS_MODULE,
1409         .release = lttng_event_release,
1410         .unlocked_ioctl = lttng_event_ioctl,
1411 #ifdef CONFIG_COMPAT
1412         .compat_ioctl = lttng_event_ioctl,
1413 #endif
1414 };
1415
1416 static int put_u64(uint64_t val, unsigned long arg)
1417 {
1418         return put_user(val, (uint64_t __user *) arg);
1419 }
1420
1421 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1422                 unsigned int cmd, unsigned long arg)
1423 {
1424         struct lib_ring_buffer *buf = filp->private_data;
1425         struct channel *chan = buf->backend.chan;
1426         const struct lib_ring_buffer_config *config = &chan->backend.config;
1427         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1428         int ret;
1429
1430         if (atomic_read(&chan->record_disabled))
1431                 return -EIO;
1432
1433         switch (cmd) {
1434         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1435         {
1436                 uint64_t ts;
1437
1438                 ret = ops->timestamp_begin(config, buf, &ts);
1439                 if (ret < 0)
1440                         goto error;
1441                 return put_u64(ts, arg);
1442         }
1443         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1444         {
1445                 uint64_t ts;
1446
1447                 ret = ops->timestamp_end(config, buf, &ts);
1448                 if (ret < 0)
1449                         goto error;
1450                 return put_u64(ts, arg);
1451         }
1452         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1453         {
1454                 uint64_t ed;
1455
1456                 ret = ops->events_discarded(config, buf, &ed);
1457                 if (ret < 0)
1458                         goto error;
1459                 return put_u64(ed, arg);
1460         }
1461         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1462         {
1463                 uint64_t cs;
1464
1465                 ret = ops->content_size(config, buf, &cs);
1466                 if (ret < 0)
1467                         goto error;
1468                 return put_u64(cs, arg);
1469         }
1470         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1471         {
1472                 uint64_t ps;
1473
1474                 ret = ops->packet_size(config, buf, &ps);
1475                 if (ret < 0)
1476                         goto error;
1477                 return put_u64(ps, arg);
1478         }
1479         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1480         {
1481                 uint64_t si;
1482
1483                 ret = ops->stream_id(config, buf, &si);
1484                 if (ret < 0)
1485                         goto error;
1486                 return put_u64(si, arg);
1487         }
1488         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1489         {
1490                 uint64_t ts;
1491
1492                 ret = ops->current_timestamp(config, buf, &ts);
1493                 if (ret < 0)
1494                         goto error;
1495                 return put_u64(ts, arg);
1496         }
1497         default:
1498                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1499                                 cmd, arg);
1500         }
1501
1502 error:
1503         return -ENOSYS;
1504 }
1505
1506 #ifdef CONFIG_COMPAT
1507 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1508                 unsigned int cmd, unsigned long arg)
1509 {
1510         struct lib_ring_buffer *buf = filp->private_data;
1511         struct channel *chan = buf->backend.chan;
1512         const struct lib_ring_buffer_config *config = &chan->backend.config;
1513         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1514         int ret;
1515
1516         if (atomic_read(&chan->record_disabled))
1517                 return -EIO;
1518
1519         switch (cmd) {
1520         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1521         {
1522                 uint64_t ts;
1523
1524                 ret = ops->timestamp_begin(config, buf, &ts);
1525                 if (ret < 0)
1526                         goto error;
1527                 return put_u64(ts, arg);
1528         }
1529         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1530         {
1531                 uint64_t ts;
1532
1533                 ret = ops->timestamp_end(config, buf, &ts);
1534                 if (ret < 0)
1535                         goto error;
1536                 return put_u64(ts, arg);
1537         }
1538         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1539         {
1540                 uint64_t ed;
1541
1542                 ret = ops->events_discarded(config, buf, &ed);
1543                 if (ret < 0)
1544                         goto error;
1545                 return put_u64(ed, arg);
1546         }
1547         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1548         {
1549                 uint64_t cs;
1550
1551                 ret = ops->content_size(config, buf, &cs);
1552                 if (ret < 0)
1553                         goto error;
1554                 return put_u64(cs, arg);
1555         }
1556         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1557         {
1558                 uint64_t ps;
1559
1560                 ret = ops->packet_size(config, buf, &ps);
1561                 if (ret < 0)
1562                         goto error;
1563                 return put_u64(ps, arg);
1564         }
1565         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1566         {
1567                 uint64_t si;
1568
1569                 ret = ops->stream_id(config, buf, &si);
1570                 if (ret < 0)
1571                         goto error;
1572                 return put_u64(si, arg);
1573         }
1574         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1575         {
1576                 uint64_t ts;
1577
1578                 ret = ops->current_timestamp(config, buf, &ts);
1579                 if (ret < 0)
1580                         goto error;
1581                 return put_u64(ts, arg);
1582         }
1583         default:
1584                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1585                                 cmd, arg);
1586         }
1587
1588 error:
1589         return -ENOSYS;
1590 }
1591 #endif /* CONFIG_COMPAT */
1592
1593 static void lttng_stream_override_ring_buffer_fops(void)
1594 {
1595         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1596         lttng_stream_ring_buffer_file_operations.open =
1597                 lib_ring_buffer_file_operations.open;
1598         lttng_stream_ring_buffer_file_operations.release =
1599                 lib_ring_buffer_file_operations.release;
1600         lttng_stream_ring_buffer_file_operations.poll =
1601                 lib_ring_buffer_file_operations.poll;
1602         lttng_stream_ring_buffer_file_operations.splice_read =
1603                 lib_ring_buffer_file_operations.splice_read;
1604         lttng_stream_ring_buffer_file_operations.mmap =
1605                 lib_ring_buffer_file_operations.mmap;
1606         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1607                 lttng_stream_ring_buffer_ioctl;
1608         lttng_stream_ring_buffer_file_operations.llseek =
1609                 lib_ring_buffer_file_operations.llseek;
1610 #ifdef CONFIG_COMPAT
1611         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1612                 lttng_stream_ring_buffer_compat_ioctl;
1613 #endif
1614 }
1615
1616 int __init lttng_abi_init(void)
1617 {
1618         int ret = 0;
1619
1620         wrapper_vmalloc_sync_all();
1621         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1622                                         &lttng_fops, NULL);
1623
1624         if (!lttng_proc_dentry) {
1625                 printk(KERN_ERR "Error creating LTTng control file\n");
1626                 ret = -ENOMEM;
1627                 goto error;
1628         }
1629         lttng_stream_override_ring_buffer_fops();
1630
1631 error:
1632         return ret;
1633 }
1634
1635 /* No __exit annotation because used by init error path too. */
1636 void lttng_abi_exit(void)
1637 {
1638         if (lttng_proc_dentry)
1639                 remove_proc_entry("lttng", NULL);
1640 }