lttng-abi.c

   1 /*
   2  * lttng-abi.c
   3  *
   4  * LTTng ABI
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  *
  23  * Mimic system calls for:
  24  * - session creation, returns a file descriptor or failure.
  25  *   - channel creation, returns a file descriptor or failure.
  26  *     - Operates on a session file descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns a file descriptor or failure.
  29  *     - Operates on a channel file descriptor.
  30  *   - stream notifier get, returns a file descriptor or failure.
  31  *     - Operates on a channel file descriptor.
  32  *   - event creation, returns a file descriptor or failure.
  33  *     - Operates on a channel file descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/anon_inodes.h>
  43 #include <linux/file.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/slab.h>
  46 #include <linux/err.h>
  47 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  48 #include "wrapper/ringbuffer/vfs.h"
  49 #include "wrapper/ringbuffer/backend.h"
  50 #include "wrapper/ringbuffer/frontend.h"
  51 #include "wrapper/poll.h"
  52 #include "lttng-abi.h"
  53 #include "lttng-abi-old.h"
  54 #include "lttng-events.h"
  55 #include "lttng-tracer.h"
  56 #include "lib/ringbuffer/frontend_types.h"
  57
  58 /*
  59  * This is LTTng's own personal way to create a system call as an external
  60  * module. We use ioctl() on /proc/lttng.
  61  */
  62
  63 static struct proc_dir_entry *lttng_proc_dentry;
  64 static const struct file_operations lttng_fops;
  65 static const struct file_operations lttng_session_fops;
  66 static const struct file_operations lttng_channel_fops;
  67 static const struct file_operations lttng_metadata_fops;
  68 static const struct file_operations lttng_event_fops;
  69 static struct file_operations lttng_stream_ring_buffer_file_operations;
  70
  71 /*
  72  * Teardown management: opened file descriptors keep a refcount on the module,
  73  * so it can only exit when all file descriptors are closed.
  74  */
  75
  76 static
  77 int lttng_abi_create_session(void)
  78 {
  79         struct lttng_session *session;
  80         struct file *session_file;
  81         int session_fd, ret;
  82
  83         session = lttng_session_create();
  84         if (!session)
  85                 return -ENOMEM;
  86         session_fd = get_unused_fd();
  87         if (session_fd < 0) {
  88                 ret = session_fd;
  89                 goto fd_error;
  90         }
  91         session_file = anon_inode_getfile("[lttng_session]",
  92                                           &lttng_session_fops,
  93                                           session, O_RDWR);
  94         if (IS_ERR(session_file)) {
  95                 ret = PTR_ERR(session_file);
  96                 goto file_error;
  97         }
  98         session->file = session_file;
  99         fd_install(session_fd, session_file);
 100         return session_fd;
 101
 102 file_error:
 103         put_unused_fd(session_fd);
 104 fd_error:
 105         lttng_session_destroy(session);
 106         return ret;
 107 }
 108
 109 static
 110 int lttng_abi_tracepoint_list(void)
 111 {
 112         struct file *tracepoint_list_file;
 113         int file_fd, ret;
 114
 115         file_fd = get_unused_fd();
 116         if (file_fd < 0) {
 117                 ret = file_fd;
 118                 goto fd_error;
 119         }
 120
 121         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 122                                           &lttng_tracepoint_list_fops,
 123                                           NULL, O_RDWR);
 124         if (IS_ERR(tracepoint_list_file)) {
 125                 ret = PTR_ERR(tracepoint_list_file);
 126                 goto file_error;
 127         }
 128         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 129         if (ret < 0)
 130                 goto open_error;
 131         fd_install(file_fd, tracepoint_list_file);
 132         if (file_fd < 0) {
 133                 ret = file_fd;
 134                 goto fd_error;
 135         }
 136         return file_fd;
 137
 138 open_error:
 139         fput(tracepoint_list_file);
 140 file_error:
 141         put_unused_fd(file_fd);
 142 fd_error:
 143         return ret;
 144 }
 145
 146 static
 147 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 148 {
 149         v->major = LTTNG_MODULES_MAJOR_VERSION;
 150         v->minor = LTTNG_MODULES_MINOR_VERSION;
 151         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 152 }
 153
 154 static
 155 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 156 {
 157         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 158         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 159 }
 160
 161 static
 162 long lttng_abi_add_context(struct file *file,
 163         struct lttng_kernel_context *context_param,
 164         struct lttng_ctx **ctx, struct lttng_session *session)
 165 {
 166
 167         if (session->been_active)
 168                 return -EPERM;
 169
 170         switch (context_param->ctx) {
 171         case LTTNG_KERNEL_CONTEXT_PID:
 172                 return lttng_add_pid_to_ctx(ctx);
 173         case LTTNG_KERNEL_CONTEXT_PRIO:
 174                 return lttng_add_prio_to_ctx(ctx);
 175         case LTTNG_KERNEL_CONTEXT_NICE:
 176                 return lttng_add_nice_to_ctx(ctx);
 177         case LTTNG_KERNEL_CONTEXT_VPID:
 178                 return lttng_add_vpid_to_ctx(ctx);
 179         case LTTNG_KERNEL_CONTEXT_TID:
 180                 return lttng_add_tid_to_ctx(ctx);
 181         case LTTNG_KERNEL_CONTEXT_VTID:
 182                 return lttng_add_vtid_to_ctx(ctx);
 183         case LTTNG_KERNEL_CONTEXT_PPID:
 184                 return lttng_add_ppid_to_ctx(ctx);
 185         case LTTNG_KERNEL_CONTEXT_VPPID:
 186                 return lttng_add_vppid_to_ctx(ctx);
 187         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 188                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 189                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 190                                 context_param->u.perf_counter.config,
 191                                 context_param->u.perf_counter.name,
 192                                 ctx);
 193         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 194                 return lttng_add_procname_to_ctx(ctx);
 195         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 196                 return lttng_add_hostname_to_ctx(ctx);
 197         default:
 198                 return -EINVAL;
 199         }
 200 }
 201
 202 /**
 203  *      lttng_ioctl - lttng syscall through ioctl
 204  *
 205  *      @file: the file
 206  *      @cmd: the command
 207  *      @arg: command arg
 208  *
 209  *      This ioctl implements lttng commands:
 210  *      LTTNG_KERNEL_SESSION
 211  *              Returns a LTTng trace session file descriptor
 212  *      LTTNG_KERNEL_TRACER_VERSION
 213  *              Returns the LTTng kernel tracer version
 214  *      LTTNG_KERNEL_TRACEPOINT_LIST
 215  *              Returns a file descriptor listing available tracepoints
 216  *      LTTNG_KERNEL_WAIT_QUIESCENT
 217  *              Returns after all previously running probes have completed
 218  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 219  *              Returns the LTTng kernel tracer ABI version
 220  *
 221  * The returned session will be deleted when its file descriptor is closed.
 222  */
 223 static
 224 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 225 {
 226         switch (cmd) {
 227         case LTTNG_KERNEL_OLD_SESSION:
 228         case LTTNG_KERNEL_SESSION:
 229                 return lttng_abi_create_session();
 230         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 231         {
 232                 struct lttng_kernel_tracer_version v;
 233                 struct lttng_kernel_old_tracer_version oldv;
 234                 struct lttng_kernel_old_tracer_version *uversion =
 235                         (struct lttng_kernel_old_tracer_version __user *) arg;
 236
 237                 lttng_abi_tracer_version(&v);
 238                 oldv.major = v.major;
 239                 oldv.minor = v.minor;
 240                 oldv.patchlevel = v.patchlevel;
 241
 242                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 243                         return -EFAULT;
 244                 return 0;
 245         }
 246         case LTTNG_KERNEL_TRACER_VERSION:
 247         {
 248                 struct lttng_kernel_tracer_version version;
 249                 struct lttng_kernel_tracer_version *uversion =
 250                         (struct lttng_kernel_tracer_version __user *) arg;
 251
 252                 lttng_abi_tracer_version(&version);
 253
 254                 if (copy_to_user(uversion, &version, sizeof(version)))
 255                         return -EFAULT;
 256                 return 0;
 257         }
 258         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 259         {
 260                 struct lttng_kernel_tracer_abi_version version;
 261                 struct lttng_kernel_tracer_abi_version *uversion =
 262                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 263
 264                 lttng_abi_tracer_abi_version(&version);
 265
 266                 if (copy_to_user(uversion, &version, sizeof(version)))
 267                         return -EFAULT;
 268                 return 0;
 269         }
 270         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 271         case LTTNG_KERNEL_TRACEPOINT_LIST:
 272                 return lttng_abi_tracepoint_list();
 273         case LTTNG_KERNEL_SYSCALL_LIST:
 274                 return lttng_abi_syscall_list();
 275         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 276         case LTTNG_KERNEL_WAIT_QUIESCENT:
 277                 synchronize_trace();
 278                 return 0;
 279         case LTTNG_KERNEL_OLD_CALIBRATE:
 280         {
 281                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 282                         (struct lttng_kernel_old_calibrate __user *) arg;
 283                 struct lttng_kernel_old_calibrate old_calibrate;
 284                 struct lttng_kernel_calibrate calibrate;
 285                 int ret;
 286
 287                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 288                         return -EFAULT;
 289                 calibrate.type = old_calibrate.type;
 290                 ret = lttng_calibrate(&calibrate);
 291                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 292                         return -EFAULT;
 293                 return ret;
 294         }
 295         case LTTNG_KERNEL_CALIBRATE:
 296         {
 297                 struct lttng_kernel_calibrate __user *ucalibrate =
 298                         (struct lttng_kernel_calibrate __user *) arg;
 299                 struct lttng_kernel_calibrate calibrate;
 300                 int ret;
 301
 302                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 303                         return -EFAULT;
 304                 ret = lttng_calibrate(&calibrate);
 305                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 306                         return -EFAULT;
 307                 return ret;
 308         }
 309         default:
 310                 return -ENOIOCTLCMD;
 311         }
 312 }
 313
 314 static const struct file_operations lttng_fops = {
 315         .owner = THIS_MODULE,
 316         .unlocked_ioctl = lttng_ioctl,
 317 #ifdef CONFIG_COMPAT
 318         .compat_ioctl = lttng_ioctl,
 319 #endif
 320 };
 321
 322 static
 323 int lttng_abi_create_channel(struct file *session_file,
 324                              struct lttng_kernel_channel *chan_param,
 325                              enum channel_type channel_type)
 326 {
 327         struct lttng_session *session = session_file->private_data;
 328         const struct file_operations *fops = NULL;
 329         const char *transport_name;
 330         struct lttng_channel *chan;
 331         struct file *chan_file;
 332         int chan_fd;
 333         int ret = 0;
 334
 335         chan_fd = get_unused_fd();
 336         if (chan_fd < 0) {
 337                 ret = chan_fd;
 338                 goto fd_error;
 339         }
 340         switch (channel_type) {
 341         case PER_CPU_CHANNEL:
 342                 fops = &lttng_channel_fops;
 343                 break;
 344         case METADATA_CHANNEL:
 345                 fops = &lttng_metadata_fops;
 346                 break;
 347         }
 348
 349         chan_file = anon_inode_getfile("[lttng_channel]",
 350                                        fops,
 351                                        NULL, O_RDWR);
 352         if (IS_ERR(chan_file)) {
 353                 ret = PTR_ERR(chan_file);
 354                 goto file_error;
 355         }
 356         switch (channel_type) {
 357         case PER_CPU_CHANNEL:
 358                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 359                         transport_name = chan_param->overwrite ?
 360                                 "relay-overwrite" : "relay-discard";
 361                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 362                         transport_name = chan_param->overwrite ?
 363                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 364                 } else {
 365                         return -EINVAL;
 366                 }
 367                 break;
 368         case METADATA_CHANNEL:
 369                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 370                         transport_name = "relay-metadata";
 371                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 372                         transport_name = "relay-metadata-mmap";
 373                 else
 374                         return -EINVAL;
 375                 break;
 376         default:
 377                 transport_name = "<unknown>";
 378                 break;
 379         }
 380         /*
 381          * We tolerate no failure path after channel creation. It will stay
 382          * invariant for the rest of the session.
 383          */
 384         chan = lttng_channel_create(session, transport_name, NULL,
 385                                   chan_param->subbuf_size,
 386                                   chan_param->num_subbuf,
 387                                   chan_param->switch_timer_interval,
 388                                   chan_param->read_timer_interval,
 389                                   channel_type);
 390         if (!chan) {
 391                 ret = -EINVAL;
 392                 goto chan_error;
 393         }
 394         chan->file = chan_file;
 395         chan_file->private_data = chan;
 396         fd_install(chan_fd, chan_file);
 397         atomic_long_inc(&session_file->f_count);
 398
 399         return chan_fd;
 400
 401 chan_error:
 402         fput(chan_file);
 403 file_error:
 404         put_unused_fd(chan_fd);
 405 fd_error:
 406         return ret;
 407 }
 408
 409 /**
 410  *      lttng_session_ioctl - lttng session fd ioctl
 411  *
 412  *      @file: the file
 413  *      @cmd: the command
 414  *      @arg: command arg
 415  *
 416  *      This ioctl implements lttng commands:
 417  *      LTTNG_KERNEL_CHANNEL
 418  *              Returns a LTTng channel file descriptor
 419  *      LTTNG_KERNEL_ENABLE
 420  *              Enables tracing for a session (weak enable)
 421  *      LTTNG_KERNEL_DISABLE
 422  *              Disables tracing for a session (strong disable)
 423  *      LTTNG_KERNEL_METADATA
 424  *              Returns a LTTng metadata file descriptor
 425  *
 426  * The returned channel will be deleted when its file descriptor is closed.
 427  */
 428 static
 429 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 430 {
 431         struct lttng_session *session = file->private_data;
 432
 433         switch (cmd) {
 434         case LTTNG_KERNEL_OLD_CHANNEL:
 435         {
 436                 struct lttng_kernel_channel chan_param;
 437                 struct lttng_kernel_old_channel old_chan_param;
 438
 439                 if (copy_from_user(&old_chan_param,
 440                                 (struct lttng_kernel_old_channel __user *) arg,
 441                                 sizeof(struct lttng_kernel_old_channel)))
 442                         return -EFAULT;
 443                 chan_param.overwrite = old_chan_param.overwrite;
 444                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 445                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 446                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 447                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 448                 chan_param.output = old_chan_param.output;
 449
 450                 return lttng_abi_create_channel(file, &chan_param,
 451                                 PER_CPU_CHANNEL);
 452         }
 453         case LTTNG_KERNEL_CHANNEL:
 454         {
 455                 struct lttng_kernel_channel chan_param;
 456
 457                 if (copy_from_user(&chan_param,
 458                                 (struct lttng_kernel_channel __user *) arg,
 459                                 sizeof(struct lttng_kernel_channel)))
 460                         return -EFAULT;
 461                 return lttng_abi_create_channel(file, &chan_param,
 462                                 PER_CPU_CHANNEL);
 463         }
 464         case LTTNG_KERNEL_OLD_SESSION_START:
 465         case LTTNG_KERNEL_OLD_ENABLE:
 466         case LTTNG_KERNEL_SESSION_START:
 467         case LTTNG_KERNEL_ENABLE:
 468                 return lttng_session_enable(session);
 469         case LTTNG_KERNEL_OLD_SESSION_STOP:
 470         case LTTNG_KERNEL_OLD_DISABLE:
 471         case LTTNG_KERNEL_SESSION_STOP:
 472         case LTTNG_KERNEL_DISABLE:
 473                 return lttng_session_disable(session);
 474         case LTTNG_KERNEL_OLD_METADATA:
 475         {
 476                 struct lttng_kernel_channel chan_param;
 477                 struct lttng_kernel_old_channel old_chan_param;
 478
 479                 if (copy_from_user(&old_chan_param,
 480                                 (struct lttng_kernel_old_channel __user *) arg,
 481                                 sizeof(struct lttng_kernel_old_channel)))
 482                         return -EFAULT;
 483                 chan_param.overwrite = old_chan_param.overwrite;
 484                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 485                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 486                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 487                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 488                 chan_param.output = old_chan_param.output;
 489
 490                 return lttng_abi_create_channel(file, &chan_param,
 491                                 METADATA_CHANNEL);
 492         }
 493         case LTTNG_KERNEL_METADATA:
 494         {
 495                 struct lttng_kernel_channel chan_param;
 496
 497                 if (copy_from_user(&chan_param,
 498                                         (struct lttng_kernel_channel __user *) arg,
 499                                         sizeof(struct lttng_kernel_channel)))
 500                         return -EFAULT;
 501                 return lttng_abi_create_channel(file, &chan_param,
 502                                 METADATA_CHANNEL);
 503         }
 504         default:
 505                 return -ENOIOCTLCMD;
 506         }
 507 }
 508
 509 /*
 510  * Called when the last file reference is dropped.
 511  *
 512  * Big fat note: channels and events are invariant for the whole session after
 513  * their creation. So this session destruction also destroys all channel and
 514  * event structures specific to this session (they are not destroyed when their
 515  * individual file is released).
 516  */
 517 static
 518 int lttng_session_release(struct inode *inode, struct file *file)
 519 {
 520         struct lttng_session *session = file->private_data;
 521
 522         if (session)
 523                 lttng_session_destroy(session);
 524         return 0;
 525 }
 526
 527 static const struct file_operations lttng_session_fops = {
 528         .owner = THIS_MODULE,
 529         .release = lttng_session_release,
 530         .unlocked_ioctl = lttng_session_ioctl,
 531 #ifdef CONFIG_COMPAT
 532         .compat_ioctl = lttng_session_ioctl,
 533 #endif
 534 };
 535
 536 /**
 537  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 538  *      @filp: the file
 539  *      @wait: poll table
 540  *
 541  *      Handles the poll operations for the metadata channels.
 542  */
 543 static
 544 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 545                 poll_table *wait)
 546 {
 547         struct lttng_metadata_stream *stream = filp->private_data;
 548         struct lib_ring_buffer *buf = stream->priv;
 549         int finalized;
 550         unsigned int mask = 0;
 551
 552         if (filp->f_mode & FMODE_READ) {
 553                 poll_wait_set_exclusive(wait);
 554                 poll_wait(filp, &stream->read_wait, wait);
 555
 556                 finalized = stream->finalized;
 557
 558                 /*
 559                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 560                  * ordering finalized load before offsets loads.
 561                  */
 562                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 563
 564                 if (finalized)
 565                         mask |= POLLHUP;
 566
 567                 if (stream->metadata_cache->metadata_written >
 568                                 stream->metadata_out)
 569                         mask |= POLLIN;
 570         }
 571
 572         return mask;
 573 }
 574
 575 static
 576 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 577                 unsigned int cmd, unsigned long arg)
 578 {
 579         struct lttng_metadata_stream *stream = filp->private_data;
 580
 581         stream->metadata_out = stream->metadata_in;
 582 }
 583
 584 static
 585 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 586                 unsigned int cmd, unsigned long arg)
 587 {
 588         int ret;
 589         struct lttng_metadata_stream *stream = filp->private_data;
 590         struct lib_ring_buffer *buf = stream->priv;
 591
 592         switch (cmd) {
 593         case RING_BUFFER_GET_NEXT_SUBBUF:
 594         {
 595                 struct lttng_metadata_stream *stream = filp->private_data;
 596                 struct lib_ring_buffer *buf = stream->priv;
 597                 struct channel *chan = buf->backend.chan;
 598
 599                 ret = lttng_metadata_output_channel(stream, chan);
 600                 if (ret > 0) {
 601                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 602                         ret = 0;
 603                 } else if (ret < 0)
 604                         goto err;
 605                 break;
 606         }
 607         case RING_BUFFER_GET_SUBBUF:
 608         {
 609                 /*
 610                  * Random access is not allowed for metadata channel.
 611                  */
 612                 return -ENOSYS;
 613         }
 614         case RING_BUFFER_FLUSH:
 615         {
 616                 struct lttng_metadata_stream *stream = filp->private_data;
 617                 struct lib_ring_buffer *buf = stream->priv;
 618                 struct channel *chan = buf->backend.chan;
 619
 620                 /*
 621                  * Before doing the actual ring buffer flush, write up to one
 622                  * packet of metadata in the ring buffer.
 623                  */
 624                 ret = lttng_metadata_output_channel(stream, chan);
 625                 if (ret < 0)
 626                         goto err;
 627                 break;
 628         }
 629         default:
 630                 break;
 631         }
 632         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 633
 634         /* Performing lib ring buffer ioctl after our own. */
 635         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 636         if (ret < 0)
 637                 goto err;
 638
 639         switch (cmd) {
 640         case RING_BUFFER_PUT_NEXT_SUBBUF:
 641         {
 642                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 643                                 cmd, arg);
 644                 break;
 645         }
 646         default:
 647                 break;
 648         }
 649 err:
 650         return ret;
 651 }
 652
 653 #ifdef CONFIG_COMPAT
 654 static
 655 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 656                 unsigned int cmd, unsigned long arg)
 657 {
 658         int ret;
 659         struct lttng_metadata_stream *stream = filp->private_data;
 660         struct lib_ring_buffer *buf = stream->priv;
 661
 662         switch (cmd) {
 663         case RING_BUFFER_GET_NEXT_SUBBUF:
 664         {
 665                 struct lttng_metadata_stream *stream = filp->private_data;
 666                 struct lib_ring_buffer *buf = stream->priv;
 667                 struct channel *chan = buf->backend.chan;
 668
 669                 ret = lttng_metadata_output_channel(stream, chan);
 670                 if (ret > 0) {
 671                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 672                         ret = 0;
 673                 } else if (ret < 0)
 674                         goto err;
 675                 break;
 676         }
 677         case RING_BUFFER_GET_SUBBUF:
 678         {
 679                 /*
 680                  * Random access is not allowed for metadata channel.
 681                  */
 682                 return -ENOSYS;
 683         }
 684         default:
 685                 break;
 686         }
 687         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 688
 689         /* Performing lib ring buffer ioctl after our own. */
 690         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 691         if (ret < 0)
 692                 goto err;
 693
 694         switch (cmd) {
 695         case RING_BUFFER_PUT_NEXT_SUBBUF:
 696         {
 697                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 698                                 cmd, arg);
 699                 break;
 700         }
 701         default:
 702                 break;
 703         }
 704 err:
 705         return ret;
 706 }
 707 #endif
 708
 709 /*
 710  * This is not used by anonymous file descriptors. This code is left
 711  * there if we ever want to implement an inode with open() operation.
 712  */
 713 static
 714 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 715 {
 716         struct lttng_metadata_stream *stream = inode->i_private;
 717         struct lib_ring_buffer *buf = stream->priv;
 718
 719         file->private_data = buf;
 720         /*
 721          * Since life-time of metadata cache differs from that of
 722          * session, we need to keep our own reference on the transport.
 723          */
 724         if (!try_module_get(stream->transport->owner)) {
 725                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 726                 return -EBUSY;
 727         }
 728         return lib_ring_buffer_open(inode, file, buf);
 729 }
 730
 731 static
 732 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 733 {
 734         struct lttng_metadata_stream *stream = file->private_data;
 735         struct lib_ring_buffer *buf = stream->priv;
 736
 737         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 738         module_put(stream->transport->owner);
 739         return lib_ring_buffer_release(inode, file, buf);
 740 }
 741
 742 static
 743 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 744                 struct pipe_inode_info *pipe, size_t len,
 745                 unsigned int flags)
 746 {
 747         struct lttng_metadata_stream *stream = in->private_data;
 748         struct lib_ring_buffer *buf = stream->priv;
 749
 750         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 751                         flags, buf);
 752 }
 753
 754 static
 755 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 756                 struct vm_area_struct *vma)
 757 {
 758         struct lttng_metadata_stream *stream = filp->private_data;
 759         struct lib_ring_buffer *buf = stream->priv;
 760
 761         return lib_ring_buffer_mmap(filp, vma, buf);
 762 }
 763
 764 static
 765 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 766         .owner = THIS_MODULE,
 767         .open = lttng_metadata_ring_buffer_open,
 768         .release = lttng_metadata_ring_buffer_release,
 769         .poll = lttng_metadata_ring_buffer_poll,
 770         .splice_read = lttng_metadata_ring_buffer_splice_read,
 771         .mmap = lttng_metadata_ring_buffer_mmap,
 772         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 773         .llseek = vfs_lib_ring_buffer_no_llseek,
 774 #ifdef CONFIG_COMPAT
 775         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 776 #endif
 777 };
 778
 779 static
 780 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 781                 const struct file_operations *fops)
 782 {
 783         int stream_fd, ret;
 784         struct file *stream_file;
 785
 786         stream_fd = get_unused_fd();
 787         if (stream_fd < 0) {
 788                 ret = stream_fd;
 789                 goto fd_error;
 790         }
 791         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 792                         stream_priv, O_RDWR);
 793         if (IS_ERR(stream_file)) {
 794                 ret = PTR_ERR(stream_file);
 795                 goto file_error;
 796         }
 797         /*
 798          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 799          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 800          * file descriptor, so we set FMODE_PREAD here.
 801          */
 802         stream_file->f_mode |= FMODE_PREAD;
 803         fd_install(stream_fd, stream_file);
 804         /*
 805          * The stream holds a reference to the channel within the generic ring
 806          * buffer library, so no need to hold a refcount on the channel and
 807          * session files here.
 808          */
 809         return stream_fd;
 810
 811 file_error:
 812         put_unused_fd(stream_fd);
 813 fd_error:
 814         return ret;
 815 }
 816
 817 static
 818 int lttng_abi_open_stream(struct file *channel_file)
 819 {
 820         struct lttng_channel *channel = channel_file->private_data;
 821         struct lib_ring_buffer *buf;
 822         int ret;
 823         void *stream_priv;
 824
 825         buf = channel->ops->buffer_read_open(channel->chan);
 826         if (!buf)
 827                 return -ENOENT;
 828
 829         stream_priv = buf;
 830         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 831                         &lttng_stream_ring_buffer_file_operations);
 832         if (ret < 0)
 833                 goto fd_error;
 834
 835         return ret;
 836
 837 fd_error:
 838         channel->ops->buffer_read_close(buf);
 839         return ret;
 840 }
 841
 842 static
 843 int lttng_abi_open_metadata_stream(struct file *channel_file)
 844 {
 845         struct lttng_channel *channel = channel_file->private_data;
 846         struct lttng_session *session = channel->session;
 847         struct lib_ring_buffer *buf;
 848         int ret;
 849         struct lttng_metadata_stream *metadata_stream;
 850         void *stream_priv;
 851
 852         buf = channel->ops->buffer_read_open(channel->chan);
 853         if (!buf)
 854                 return -ENOENT;
 855
 856         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 857                         GFP_KERNEL);
 858         if (!metadata_stream) {
 859                 ret = -ENOMEM;
 860                 goto nomem;
 861         }
 862         metadata_stream->metadata_cache = session->metadata_cache;
 863         init_waitqueue_head(&metadata_stream->read_wait);
 864         metadata_stream->priv = buf;
 865         stream_priv = metadata_stream;
 866         metadata_stream->transport = channel->transport;
 867         mutex_init(&metadata_stream->lock);
 868
 869         /*
 870          * Since life-time of metadata cache differs from that of
 871          * session, we need to keep our own reference on the transport.
 872          */
 873         if (!try_module_get(metadata_stream->transport->owner)) {
 874                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 875                 ret = -EINVAL;
 876                 goto notransport;
 877         }
 878
 879         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 880                         &lttng_metadata_ring_buffer_file_operations);
 881         if (ret < 0)
 882                 goto fd_error;
 883
 884         kref_get(&session->metadata_cache->refcount);
 885         list_add(&metadata_stream->list,
 886                 &session->metadata_cache->metadata_stream);
 887         return ret;
 888
 889 fd_error:
 890         module_put(metadata_stream->transport->owner);
 891 notransport:
 892         kfree(metadata_stream);
 893 nomem:
 894         channel->ops->buffer_read_close(buf);
 895         return ret;
 896 }
 897
 898 static
 899 int lttng_abi_create_event(struct file *channel_file,
 900                            struct lttng_kernel_event *event_param)
 901 {
 902         struct lttng_channel *channel = channel_file->private_data;
 903         struct lttng_event *event;
 904         int event_fd, ret;
 905         struct file *event_file;
 906
 907         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 908         switch (event_param->instrumentation) {
 909         case LTTNG_KERNEL_KRETPROBE:
 910                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 911                 break;
 912         case LTTNG_KERNEL_KPROBE:
 913                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 914                 break;
 915         case LTTNG_KERNEL_FUNCTION:
 916                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 917                 break;
 918         default:
 919                 break;
 920         }
 921         switch (event_param->instrumentation) {
 922         default:
 923                 event_fd = get_unused_fd();
 924                 if (event_fd < 0) {
 925                         ret = event_fd;
 926                         goto fd_error;
 927                 }
 928                 event_file = anon_inode_getfile("[lttng_event]",
 929                                                 &lttng_event_fops,
 930                                                 NULL, O_RDWR);
 931                 if (IS_ERR(event_file)) {
 932                         ret = PTR_ERR(event_file);
 933                         goto file_error;
 934                 }
 935                 /*
 936                  * We tolerate no failure path after event creation. It
 937                  * will stay invariant for the rest of the session.
 938                  */
 939                 event = lttng_event_create(channel, event_param, NULL, NULL);
 940                 WARN_ON_ONCE(!event);
 941                 if (IS_ERR(event)) {
 942                         ret = PTR_ERR(event);
 943                         goto event_error;
 944                 }
 945                 event_file->private_data = event;
 946                 fd_install(event_fd, event_file);
 947                 /* The event holds a reference on the channel */
 948                 atomic_long_inc(&channel_file->f_count);
 949                 break;
 950         case LTTNG_KERNEL_SYSCALL:
 951                 ret = lttng_syscalls_register(channel, NULL);
 952                 if (ret)
 953                         goto fd_error;
 954                 event_fd = 0;
 955                 if (event_param->u.syscall.enable) {
 956                         ret = lttng_syscall_filter_enable(channel,
 957                                 event_param->name[0] == '\0' ?
 958                                         NULL : event_param->name);
 959                         if (ret)
 960                                 goto fd_error;
 961
 962                 } else {
 963                         ret = lttng_syscall_filter_disable(channel,
 964                                 event_param->name[0] == '\0' ?
 965                                         NULL : event_param->name);
 966                         if (ret)
 967                                 goto fd_error;
 968                 }
 969                 break;
 970         }
 971         return event_fd;
 972
 973 event_error:
 974         fput(event_file);
 975 file_error:
 976         put_unused_fd(event_fd);
 977 fd_error:
 978         return ret;
 979 }
 980
 981 /**
 982  *      lttng_channel_ioctl - lttng syscall through ioctl
 983  *
 984  *      @file: the file
 985  *      @cmd: the command
 986  *      @arg: command arg
 987  *
 988  *      This ioctl implements lttng commands:
 989  *      LTTNG_KERNEL_STREAM
 990  *              Returns an event stream file descriptor or failure.
 991  *              (typically, one event stream records events from one CPU)
 992  *      LTTNG_KERNEL_EVENT
 993  *              Returns an event file descriptor or failure.
 994  *      LTTNG_KERNEL_CONTEXT
 995  *              Prepend a context field to each event in the channel
 996  *      LTTNG_KERNEL_ENABLE
 997  *              Enable recording for events in this channel (weak enable)
 998  *      LTTNG_KERNEL_DISABLE
 999  *              Disable recording for events in this channel (strong disable)
1000  *
1001  * Channel and event file descriptors also hold a reference on the session.
1002  */
1003 static
1004 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1005 {
1006         struct lttng_channel *channel = file->private_data;
1007
1008         switch (cmd) {
1009         case LTTNG_KERNEL_OLD_STREAM:
1010         case LTTNG_KERNEL_STREAM:
1011                 return lttng_abi_open_stream(file);
1012         case LTTNG_KERNEL_OLD_EVENT:
1013         {
1014                 struct lttng_kernel_event *uevent_param;
1015                 struct lttng_kernel_old_event *old_uevent_param;
1016                 int ret;
1017
1018                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1019                                 GFP_KERNEL);
1020                 if (!uevent_param) {
1021                         ret = -ENOMEM;
1022                         goto old_event_end;
1023                 }
1024                 old_uevent_param = kmalloc(
1025                                 sizeof(struct lttng_kernel_old_event),
1026                                 GFP_KERNEL);
1027                 if (!old_uevent_param) {
1028                         ret = -ENOMEM;
1029                         goto old_event_error_free_param;
1030                 }
1031                 if (copy_from_user(old_uevent_param,
1032                                 (struct lttng_kernel_old_event __user *) arg,
1033                                 sizeof(struct lttng_kernel_old_event))) {
1034                         ret = -EFAULT;
1035                         goto old_event_error_free_old_param;
1036                 }
1037
1038                 memcpy(uevent_param->name, old_uevent_param->name,
1039                                 sizeof(uevent_param->name));
1040                 uevent_param->instrumentation =
1041                         old_uevent_param->instrumentation;
1042
1043                 switch (old_uevent_param->instrumentation) {
1044                 case LTTNG_KERNEL_KPROBE:
1045                         uevent_param->u.kprobe.addr =
1046                                 old_uevent_param->u.kprobe.addr;
1047                         uevent_param->u.kprobe.offset =
1048                                 old_uevent_param->u.kprobe.offset;
1049                         memcpy(uevent_param->u.kprobe.symbol_name,
1050                                 old_uevent_param->u.kprobe.symbol_name,
1051                                 sizeof(uevent_param->u.kprobe.symbol_name));
1052                         break;
1053                 case LTTNG_KERNEL_KRETPROBE:
1054                         uevent_param->u.kretprobe.addr =
1055                                 old_uevent_param->u.kretprobe.addr;
1056                         uevent_param->u.kretprobe.offset =
1057                                 old_uevent_param->u.kretprobe.offset;
1058                         memcpy(uevent_param->u.kretprobe.symbol_name,
1059                                 old_uevent_param->u.kretprobe.symbol_name,
1060                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1061                         break;
1062                 case LTTNG_KERNEL_FUNCTION:
1063                         memcpy(uevent_param->u.ftrace.symbol_name,
1064                                         old_uevent_param->u.ftrace.symbol_name,
1065                                         sizeof(uevent_param->u.ftrace.symbol_name));
1066                         break;
1067                 default:
1068                         break;
1069                 }
1070                 ret = lttng_abi_create_event(file, uevent_param);
1071
1072 old_event_error_free_old_param:
1073                 kfree(old_uevent_param);
1074 old_event_error_free_param:
1075                 kfree(uevent_param);
1076 old_event_end:
1077                 return ret;
1078         }
1079         case LTTNG_KERNEL_EVENT:
1080         {
1081                 struct lttng_kernel_event uevent_param;
1082
1083                 if (copy_from_user(&uevent_param,
1084                                 (struct lttng_kernel_event __user *) arg,
1085                                 sizeof(uevent_param)))
1086                         return -EFAULT;
1087                 return lttng_abi_create_event(file, &uevent_param);
1088         }
1089         case LTTNG_KERNEL_OLD_CONTEXT:
1090         {
1091                 struct lttng_kernel_context *ucontext_param;
1092                 struct lttng_kernel_old_context *old_ucontext_param;
1093                 int ret;
1094
1095                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1096                                 GFP_KERNEL);
1097                 if (!ucontext_param) {
1098                         ret = -ENOMEM;
1099                         goto old_ctx_end;
1100                 }
1101                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1102                                 GFP_KERNEL);
1103                 if (!old_ucontext_param) {
1104                         ret = -ENOMEM;
1105                         goto old_ctx_error_free_param;
1106                 }
1107
1108                 if (copy_from_user(old_ucontext_param,
1109                                 (struct lttng_kernel_old_context __user *) arg,
1110                                 sizeof(struct lttng_kernel_old_context))) {
1111                         ret = -EFAULT;
1112                         goto old_ctx_error_free_old_param;
1113                 }
1114                 ucontext_param->ctx = old_ucontext_param->ctx;
1115                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1116                                 sizeof(ucontext_param->padding));
1117                 /* only type that uses the union */
1118                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1119                         ucontext_param->u.perf_counter.type =
1120                                 old_ucontext_param->u.perf_counter.type;
1121                         ucontext_param->u.perf_counter.config =
1122                                 old_ucontext_param->u.perf_counter.config;
1123                         memcpy(ucontext_param->u.perf_counter.name,
1124                                 old_ucontext_param->u.perf_counter.name,
1125                                 sizeof(ucontext_param->u.perf_counter.name));
1126                 }
1127
1128                 ret = lttng_abi_add_context(file,
1129                                 ucontext_param,
1130                                 &channel->ctx, channel->session);
1131
1132 old_ctx_error_free_old_param:
1133                 kfree(old_ucontext_param);
1134 old_ctx_error_free_param:
1135                 kfree(ucontext_param);
1136 old_ctx_end:
1137                 return ret;
1138         }
1139         case LTTNG_KERNEL_CONTEXT:
1140         {
1141                 struct lttng_kernel_context ucontext_param;
1142
1143                 if (copy_from_user(&ucontext_param,
1144                                 (struct lttng_kernel_context __user *) arg,
1145                                 sizeof(ucontext_param)))
1146                         return -EFAULT;
1147                 return lttng_abi_add_context(file,
1148                                 &ucontext_param,
1149                                 &channel->ctx, channel->session);
1150         }
1151         case LTTNG_KERNEL_OLD_ENABLE:
1152         case LTTNG_KERNEL_ENABLE:
1153                 return lttng_channel_enable(channel);
1154         case LTTNG_KERNEL_OLD_DISABLE:
1155         case LTTNG_KERNEL_DISABLE:
1156                 return lttng_channel_disable(channel);
1157         case LTTNG_KERNEL_SYSCALL_MASK:
1158                 return lttng_channel_syscall_mask(channel,
1159                         (struct lttng_kernel_syscall_mask __user *) arg);
1160         default:
1161                 return -ENOIOCTLCMD;
1162         }
1163
1164 }
1165
1166 /**
1167  *      lttng_metadata_ioctl - lttng syscall through ioctl
1168  *
1169  *      @file: the file
1170  *      @cmd: the command
1171  *      @arg: command arg
1172  *
1173  *      This ioctl implements lttng commands:
1174  *      LTTNG_KERNEL_STREAM
1175  *              Returns an event stream file descriptor or failure.
1176  *
1177  * Channel and event file descriptors also hold a reference on the session.
1178  */
1179 static
1180 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1181 {
1182         switch (cmd) {
1183         case LTTNG_KERNEL_OLD_STREAM:
1184         case LTTNG_KERNEL_STREAM:
1185                 return lttng_abi_open_metadata_stream(file);
1186         default:
1187                 return -ENOIOCTLCMD;
1188         }
1189 }
1190
1191 /**
1192  *      lttng_channel_poll - lttng stream addition/removal monitoring
1193  *
1194  *      @file: the file
1195  *      @wait: poll table
1196  */
1197 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1198 {
1199         struct lttng_channel *channel = file->private_data;
1200         unsigned int mask = 0;
1201
1202         if (file->f_mode & FMODE_READ) {
1203                 poll_wait_set_exclusive(wait);
1204                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1205                           wait);
1206
1207                 if (channel->ops->is_disabled(channel->chan))
1208                         return POLLERR;
1209                 if (channel->ops->is_finalized(channel->chan))
1210                         return POLLHUP;
1211                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1212                         return POLLIN | POLLRDNORM;
1213                 return 0;
1214         }
1215         return mask;
1216
1217 }
1218
1219 static
1220 int lttng_channel_release(struct inode *inode, struct file *file)
1221 {
1222         struct lttng_channel *channel = file->private_data;
1223
1224         if (channel)
1225                 fput(channel->session->file);
1226         return 0;
1227 }
1228
1229 static
1230 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1231 {
1232         struct lttng_channel *channel = file->private_data;
1233
1234         if (channel) {
1235                 lttng_metadata_channel_destroy(channel);
1236                 fput(channel->session->file);
1237         }
1238
1239         return 0;
1240 }
1241
1242 static const struct file_operations lttng_channel_fops = {
1243         .owner = THIS_MODULE,
1244         .release = lttng_channel_release,
1245         .poll = lttng_channel_poll,
1246         .unlocked_ioctl = lttng_channel_ioctl,
1247 #ifdef CONFIG_COMPAT
1248         .compat_ioctl = lttng_channel_ioctl,
1249 #endif
1250 };
1251
1252 static const struct file_operations lttng_metadata_fops = {
1253         .owner = THIS_MODULE,
1254         .release = lttng_metadata_channel_release,
1255         .unlocked_ioctl = lttng_metadata_ioctl,
1256 #ifdef CONFIG_COMPAT
1257         .compat_ioctl = lttng_metadata_ioctl,
1258 #endif
1259 };
1260
1261 /**
1262  *      lttng_event_ioctl - lttng syscall through ioctl
1263  *
1264  *      @file: the file
1265  *      @cmd: the command
1266  *      @arg: command arg
1267  *
1268  *      This ioctl implements lttng commands:
1269  *      LTTNG_KERNEL_CONTEXT
1270  *              Prepend a context field to each record of this event
1271  *      LTTNG_KERNEL_ENABLE
1272  *              Enable recording for this event (weak enable)
1273  *      LTTNG_KERNEL_DISABLE
1274  *              Disable recording for this event (strong disable)
1275  */
1276 static
1277 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1278 {
1279         struct lttng_event *event = file->private_data;
1280
1281         switch (cmd) {
1282         case LTTNG_KERNEL_OLD_CONTEXT:
1283         {
1284                 struct lttng_kernel_context *ucontext_param;
1285                 struct lttng_kernel_old_context *old_ucontext_param;
1286                 int ret;
1287
1288                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1289                                 GFP_KERNEL);
1290                 if (!ucontext_param) {
1291                         ret = -ENOMEM;
1292                         goto old_ctx_end;
1293                 }
1294                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1295                                 GFP_KERNEL);
1296                 if (!old_ucontext_param) {
1297                         ret = -ENOMEM;
1298                         goto old_ctx_error_free_param;
1299                 }
1300
1301                 if (copy_from_user(old_ucontext_param,
1302                                         (struct lttng_kernel_old_context __user *) arg,
1303                                         sizeof(struct lttng_kernel_old_context))) {
1304                         ret = -EFAULT;
1305                         goto old_ctx_error_free_old_param;
1306                 }
1307                 ucontext_param->ctx = old_ucontext_param->ctx;
1308                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1309                                 sizeof(ucontext_param->padding));
1310                 /* only type that uses the union */
1311                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1312                         ucontext_param->u.perf_counter.type =
1313                                 old_ucontext_param->u.perf_counter.type;
1314                         ucontext_param->u.perf_counter.config =
1315                                 old_ucontext_param->u.perf_counter.config;
1316                         memcpy(ucontext_param->u.perf_counter.name,
1317                                         old_ucontext_param->u.perf_counter.name,
1318                                         sizeof(ucontext_param->u.perf_counter.name));
1319                 }
1320
1321                 ret = lttng_abi_add_context(file,
1322                                 ucontext_param,
1323                                 &event->ctx, event->chan->session);
1324
1325 old_ctx_error_free_old_param:
1326                 kfree(old_ucontext_param);
1327 old_ctx_error_free_param:
1328                 kfree(ucontext_param);
1329 old_ctx_end:
1330                 return ret;
1331         }
1332         case LTTNG_KERNEL_CONTEXT:
1333         {
1334                 struct lttng_kernel_context ucontext_param;
1335
1336                 if (copy_from_user(&ucontext_param,
1337                                         (struct lttng_kernel_context __user *) arg,
1338                                         sizeof(ucontext_param)))
1339                         return -EFAULT;
1340                 return lttng_abi_add_context(file,
1341                                 &ucontext_param,
1342                                 &event->ctx, event->chan->session);
1343         }
1344         case LTTNG_KERNEL_OLD_ENABLE:
1345         case LTTNG_KERNEL_ENABLE:
1346                 return lttng_event_enable(event);
1347         case LTTNG_KERNEL_OLD_DISABLE:
1348         case LTTNG_KERNEL_DISABLE:
1349                 return lttng_event_disable(event);
1350         default:
1351                 return -ENOIOCTLCMD;
1352         }
1353 }
1354
1355 static
1356 int lttng_event_release(struct inode *inode, struct file *file)
1357 {
1358         struct lttng_event *event = file->private_data;
1359
1360         if (event)
1361                 fput(event->chan->file);
1362         return 0;
1363 }
1364
1365 /* TODO: filter control ioctl */
1366 static const struct file_operations lttng_event_fops = {
1367         .owner = THIS_MODULE,
1368         .release = lttng_event_release,
1369         .unlocked_ioctl = lttng_event_ioctl,
1370 #ifdef CONFIG_COMPAT
1371         .compat_ioctl = lttng_event_ioctl,
1372 #endif
1373 };
1374
1375 static int put_u64(uint64_t val, unsigned long arg)
1376 {
1377         return put_user(val, (uint64_t __user *) arg);
1378 }
1379
1380 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1381                 unsigned int cmd, unsigned long arg)
1382 {
1383         struct lib_ring_buffer *buf = filp->private_data;
1384         struct channel *chan = buf->backend.chan;
1385         const struct lib_ring_buffer_config *config = &chan->backend.config;
1386         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1387         int ret;
1388
1389         if (atomic_read(&chan->record_disabled))
1390                 return -EIO;
1391
1392         switch (cmd) {
1393         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1394         {
1395                 uint64_t ts;
1396
1397                 ret = ops->timestamp_begin(config, buf, &ts);
1398                 if (ret < 0)
1399                         goto error;
1400                 return put_u64(ts, arg);
1401         }
1402         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1403         {
1404                 uint64_t ts;
1405
1406                 ret = ops->timestamp_end(config, buf, &ts);
1407                 if (ret < 0)
1408                         goto error;
1409                 return put_u64(ts, arg);
1410         }
1411         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1412         {
1413                 uint64_t ed;
1414
1415                 ret = ops->events_discarded(config, buf, &ed);
1416                 if (ret < 0)
1417                         goto error;
1418                 return put_u64(ed, arg);
1419         }
1420         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1421         {
1422                 uint64_t cs;
1423
1424                 ret = ops->content_size(config, buf, &cs);
1425                 if (ret < 0)
1426                         goto error;
1427                 return put_u64(cs, arg);
1428         }
1429         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1430         {
1431                 uint64_t ps;
1432
1433                 ret = ops->packet_size(config, buf, &ps);
1434                 if (ret < 0)
1435                         goto error;
1436                 return put_u64(ps, arg);
1437         }
1438         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1439         {
1440                 uint64_t si;
1441
1442                 ret = ops->stream_id(config, buf, &si);
1443                 if (ret < 0)
1444                         goto error;
1445                 return put_u64(si, arg);
1446         }
1447         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1448         {
1449                 uint64_t ts;
1450
1451                 ret = ops->current_timestamp(config, buf, &ts);
1452                 if (ret < 0)
1453                         goto error;
1454                 return put_u64(ts, arg);
1455         }
1456         default:
1457                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1458                                 cmd, arg);
1459         }
1460
1461 error:
1462         return -ENOSYS;
1463 }
1464
1465 #ifdef CONFIG_COMPAT
1466 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1467                 unsigned int cmd, unsigned long arg)
1468 {
1469         struct lib_ring_buffer *buf = filp->private_data;
1470         struct channel *chan = buf->backend.chan;
1471         const struct lib_ring_buffer_config *config = &chan->backend.config;
1472         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1473         int ret;
1474
1475         if (atomic_read(&chan->record_disabled))
1476                 return -EIO;
1477
1478         switch (cmd) {
1479         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1480         {
1481                 uint64_t ts;
1482
1483                 ret = ops->timestamp_begin(config, buf, &ts);
1484                 if (ret < 0)
1485                         goto error;
1486                 return put_u64(ts, arg);
1487         }
1488         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1489         {
1490                 uint64_t ts;
1491
1492                 ret = ops->timestamp_end(config, buf, &ts);
1493                 if (ret < 0)
1494                         goto error;
1495                 return put_u64(ts, arg);
1496         }
1497         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1498         {
1499                 uint64_t ed;
1500
1501                 ret = ops->events_discarded(config, buf, &ed);
1502                 if (ret < 0)
1503                         goto error;
1504                 return put_u64(ed, arg);
1505         }
1506         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1507         {
1508                 uint64_t cs;
1509
1510                 ret = ops->content_size(config, buf, &cs);
1511                 if (ret < 0)
1512                         goto error;
1513                 return put_u64(cs, arg);
1514         }
1515         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1516         {
1517                 uint64_t ps;
1518
1519                 ret = ops->packet_size(config, buf, &ps);
1520                 if (ret < 0)
1521                         goto error;
1522                 return put_u64(ps, arg);
1523         }
1524         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1525         {
1526                 uint64_t si;
1527
1528                 ret = ops->stream_id(config, buf, &si);
1529                 if (ret < 0)
1530                         goto error;
1531                 return put_u64(si, arg);
1532         }
1533         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1534         {
1535                 uint64_t ts;
1536
1537                 ret = ops->current_timestamp(config, buf, &ts);
1538                 if (ret < 0)
1539                         goto error;
1540                 return put_u64(ts, arg);
1541         }
1542         default:
1543                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1544                                 cmd, arg);
1545         }
1546
1547 error:
1548         return -ENOSYS;
1549 }
1550 #endif /* CONFIG_COMPAT */
1551
1552 static void lttng_stream_override_ring_buffer_fops(void)
1553 {
1554         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1555         lttng_stream_ring_buffer_file_operations.open =
1556                 lib_ring_buffer_file_operations.open;
1557         lttng_stream_ring_buffer_file_operations.release =
1558                 lib_ring_buffer_file_operations.release;
1559         lttng_stream_ring_buffer_file_operations.poll =
1560                 lib_ring_buffer_file_operations.poll;
1561         lttng_stream_ring_buffer_file_operations.splice_read =
1562                 lib_ring_buffer_file_operations.splice_read;
1563         lttng_stream_ring_buffer_file_operations.mmap =
1564                 lib_ring_buffer_file_operations.mmap;
1565         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1566                 lttng_stream_ring_buffer_ioctl;
1567         lttng_stream_ring_buffer_file_operations.llseek =
1568                 lib_ring_buffer_file_operations.llseek;
1569 #ifdef CONFIG_COMPAT
1570         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1571                 lttng_stream_ring_buffer_compat_ioctl;
1572 #endif
1573 }
1574
1575 int __init lttng_abi_init(void)
1576 {
1577         int ret = 0;
1578
1579         wrapper_vmalloc_sync_all();
1580         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1581                                         &lttng_fops, NULL);
1582
1583         if (!lttng_proc_dentry) {
1584                 printk(KERN_ERR "Error creating LTTng control file\n");
1585                 ret = -ENOMEM;
1586                 goto error;
1587         }
1588         lttng_stream_override_ring_buffer_fops();
1589
1590 error:
1591         return ret;
1592 }
1593
1594 /* No __exit annotation because used by init error path too. */
1595 void lttng_abi_exit(void)
1596 {
1597         if (lttng_proc_dentry)
1598                 remove_proc_entry("lttng", NULL);
1599 }