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  *      LTTNG_KERNEL_SESSION_TRACK_PID
 427  *              Add PID to session tracker
 428  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 429  *              Remove PID from session tracker
 430  *
 431  * The returned channel will be deleted when its file descriptor is closed.
 432  */
 433 static
 434 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 435 {
 436         struct lttng_session *session = file->private_data;
 437
 438         switch (cmd) {
 439         case LTTNG_KERNEL_OLD_CHANNEL:
 440         {
 441                 struct lttng_kernel_channel chan_param;
 442                 struct lttng_kernel_old_channel old_chan_param;
 443
 444                 if (copy_from_user(&old_chan_param,
 445                                 (struct lttng_kernel_old_channel __user *) arg,
 446                                 sizeof(struct lttng_kernel_old_channel)))
 447                         return -EFAULT;
 448                 chan_param.overwrite = old_chan_param.overwrite;
 449                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 450                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 451                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 452                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 453                 chan_param.output = old_chan_param.output;
 454
 455                 return lttng_abi_create_channel(file, &chan_param,
 456                                 PER_CPU_CHANNEL);
 457         }
 458         case LTTNG_KERNEL_CHANNEL:
 459         {
 460                 struct lttng_kernel_channel chan_param;
 461
 462                 if (copy_from_user(&chan_param,
 463                                 (struct lttng_kernel_channel __user *) arg,
 464                                 sizeof(struct lttng_kernel_channel)))
 465                         return -EFAULT;
 466                 return lttng_abi_create_channel(file, &chan_param,
 467                                 PER_CPU_CHANNEL);
 468         }
 469         case LTTNG_KERNEL_OLD_SESSION_START:
 470         case LTTNG_KERNEL_OLD_ENABLE:
 471         case LTTNG_KERNEL_SESSION_START:
 472         case LTTNG_KERNEL_ENABLE:
 473                 return lttng_session_enable(session);
 474         case LTTNG_KERNEL_OLD_SESSION_STOP:
 475         case LTTNG_KERNEL_OLD_DISABLE:
 476         case LTTNG_KERNEL_SESSION_STOP:
 477         case LTTNG_KERNEL_DISABLE:
 478                 return lttng_session_disable(session);
 479         case LTTNG_KERNEL_OLD_METADATA:
 480         {
 481                 struct lttng_kernel_channel chan_param;
 482                 struct lttng_kernel_old_channel old_chan_param;
 483
 484                 if (copy_from_user(&old_chan_param,
 485                                 (struct lttng_kernel_old_channel __user *) arg,
 486                                 sizeof(struct lttng_kernel_old_channel)))
 487                         return -EFAULT;
 488                 chan_param.overwrite = old_chan_param.overwrite;
 489                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 490                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 491                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 492                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 493                 chan_param.output = old_chan_param.output;
 494
 495                 return lttng_abi_create_channel(file, &chan_param,
 496                                 METADATA_CHANNEL);
 497         }
 498         case LTTNG_KERNEL_METADATA:
 499         {
 500                 struct lttng_kernel_channel chan_param;
 501
 502                 if (copy_from_user(&chan_param,
 503                                         (struct lttng_kernel_channel __user *) arg,
 504                                         sizeof(struct lttng_kernel_channel)))
 505                         return -EFAULT;
 506                 return lttng_abi_create_channel(file, &chan_param,
 507                                 METADATA_CHANNEL);
 508         }
 509         case LTTNG_KERNEL_SESSION_TRACK_PID:
 510                 return lttng_session_track_pid(session, (int) arg);
 511         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 512                 return lttng_session_untrack_pid(session, (int) arg);
 513         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 514                 return lttng_session_list_tracker_pids(session);
 515         default:
 516                 return -ENOIOCTLCMD;
 517         }
 518 }
 519
 520 /*
 521  * Called when the last file reference is dropped.
 522  *
 523  * Big fat note: channels and events are invariant for the whole session after
 524  * their creation. So this session destruction also destroys all channel and
 525  * event structures specific to this session (they are not destroyed when their
 526  * individual file is released).
 527  */
 528 static
 529 int lttng_session_release(struct inode *inode, struct file *file)
 530 {
 531         struct lttng_session *session = file->private_data;
 532
 533         if (session)
 534                 lttng_session_destroy(session);
 535         return 0;
 536 }
 537
 538 static const struct file_operations lttng_session_fops = {
 539         .owner = THIS_MODULE,
 540         .release = lttng_session_release,
 541         .unlocked_ioctl = lttng_session_ioctl,
 542 #ifdef CONFIG_COMPAT
 543         .compat_ioctl = lttng_session_ioctl,
 544 #endif
 545 };
 546
 547 /**
 548  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 549  *      @filp: the file
 550  *      @wait: poll table
 551  *
 552  *      Handles the poll operations for the metadata channels.
 553  */
 554 static
 555 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 556                 poll_table *wait)
 557 {
 558         struct lttng_metadata_stream *stream = filp->private_data;
 559         struct lib_ring_buffer *buf = stream->priv;
 560         int finalized;
 561         unsigned int mask = 0;
 562
 563         if (filp->f_mode & FMODE_READ) {
 564                 poll_wait_set_exclusive(wait);
 565                 poll_wait(filp, &stream->read_wait, wait);
 566
 567                 finalized = stream->finalized;
 568
 569                 /*
 570                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 571                  * ordering finalized load before offsets loads.
 572                  */
 573                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 574
 575                 if (finalized)
 576                         mask |= POLLHUP;
 577
 578                 if (stream->metadata_cache->metadata_written >
 579                                 stream->metadata_out)
 580                         mask |= POLLIN;
 581         }
 582
 583         return mask;
 584 }
 585
 586 static
 587 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 588                 unsigned int cmd, unsigned long arg)
 589 {
 590         struct lttng_metadata_stream *stream = filp->private_data;
 591
 592         stream->metadata_out = stream->metadata_in;
 593 }
 594
 595 static
 596 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 597                 unsigned int cmd, unsigned long arg)
 598 {
 599         int ret;
 600         struct lttng_metadata_stream *stream = filp->private_data;
 601         struct lib_ring_buffer *buf = stream->priv;
 602
 603         switch (cmd) {
 604         case RING_BUFFER_GET_NEXT_SUBBUF:
 605         {
 606                 struct lttng_metadata_stream *stream = filp->private_data;
 607                 struct lib_ring_buffer *buf = stream->priv;
 608                 struct channel *chan = buf->backend.chan;
 609
 610                 ret = lttng_metadata_output_channel(stream, chan);
 611                 if (ret > 0) {
 612                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 613                         ret = 0;
 614                 } else if (ret < 0)
 615                         goto err;
 616                 break;
 617         }
 618         case RING_BUFFER_GET_SUBBUF:
 619         {
 620                 /*
 621                  * Random access is not allowed for metadata channel.
 622                  */
 623                 return -ENOSYS;
 624         }
 625         case RING_BUFFER_FLUSH:
 626         {
 627                 struct lttng_metadata_stream *stream = filp->private_data;
 628                 struct lib_ring_buffer *buf = stream->priv;
 629                 struct channel *chan = buf->backend.chan;
 630
 631                 /*
 632                  * Before doing the actual ring buffer flush, write up to one
 633                  * packet of metadata in the ring buffer.
 634                  */
 635                 ret = lttng_metadata_output_channel(stream, chan);
 636                 if (ret < 0)
 637                         goto err;
 638                 break;
 639         }
 640         default:
 641                 break;
 642         }
 643         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 644
 645         /* Performing lib ring buffer ioctl after our own. */
 646         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 647         if (ret < 0)
 648                 goto err;
 649
 650         switch (cmd) {
 651         case RING_BUFFER_PUT_NEXT_SUBBUF:
 652         {
 653                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 654                                 cmd, arg);
 655                 break;
 656         }
 657         default:
 658                 break;
 659         }
 660 err:
 661         return ret;
 662 }
 663
 664 #ifdef CONFIG_COMPAT
 665 static
 666 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 667                 unsigned int cmd, unsigned long arg)
 668 {
 669         int ret;
 670         struct lttng_metadata_stream *stream = filp->private_data;
 671         struct lib_ring_buffer *buf = stream->priv;
 672
 673         switch (cmd) {
 674         case RING_BUFFER_GET_NEXT_SUBBUF:
 675         {
 676                 struct lttng_metadata_stream *stream = filp->private_data;
 677                 struct lib_ring_buffer *buf = stream->priv;
 678                 struct channel *chan = buf->backend.chan;
 679
 680                 ret = lttng_metadata_output_channel(stream, chan);
 681                 if (ret > 0) {
 682                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 683                         ret = 0;
 684                 } else if (ret < 0)
 685                         goto err;
 686                 break;
 687         }
 688         case RING_BUFFER_GET_SUBBUF:
 689         {
 690                 /*
 691                  * Random access is not allowed for metadata channel.
 692                  */
 693                 return -ENOSYS;
 694         }
 695         default:
 696                 break;
 697         }
 698         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 699
 700         /* Performing lib ring buffer ioctl after our own. */
 701         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 702         if (ret < 0)
 703                 goto err;
 704
 705         switch (cmd) {
 706         case RING_BUFFER_PUT_NEXT_SUBBUF:
 707         {
 708                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 709                                 cmd, arg);
 710                 break;
 711         }
 712         default:
 713                 break;
 714         }
 715 err:
 716         return ret;
 717 }
 718 #endif
 719
 720 /*
 721  * This is not used by anonymous file descriptors. This code is left
 722  * there if we ever want to implement an inode with open() operation.
 723  */
 724 static
 725 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 726 {
 727         struct lttng_metadata_stream *stream = inode->i_private;
 728         struct lib_ring_buffer *buf = stream->priv;
 729
 730         file->private_data = buf;
 731         /*
 732          * Since life-time of metadata cache differs from that of
 733          * session, we need to keep our own reference on the transport.
 734          */
 735         if (!try_module_get(stream->transport->owner)) {
 736                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 737                 return -EBUSY;
 738         }
 739         return lib_ring_buffer_open(inode, file, buf);
 740 }
 741
 742 static
 743 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 744 {
 745         struct lttng_metadata_stream *stream = file->private_data;
 746         struct lib_ring_buffer *buf = stream->priv;
 747
 748         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 749         module_put(stream->transport->owner);
 750         return lib_ring_buffer_release(inode, file, buf);
 751 }
 752
 753 static
 754 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 755                 struct pipe_inode_info *pipe, size_t len,
 756                 unsigned int flags)
 757 {
 758         struct lttng_metadata_stream *stream = in->private_data;
 759         struct lib_ring_buffer *buf = stream->priv;
 760
 761         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 762                         flags, buf);
 763 }
 764
 765 static
 766 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 767                 struct vm_area_struct *vma)
 768 {
 769         struct lttng_metadata_stream *stream = filp->private_data;
 770         struct lib_ring_buffer *buf = stream->priv;
 771
 772         return lib_ring_buffer_mmap(filp, vma, buf);
 773 }
 774
 775 static
 776 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 777         .owner = THIS_MODULE,
 778         .open = lttng_metadata_ring_buffer_open,
 779         .release = lttng_metadata_ring_buffer_release,
 780         .poll = lttng_metadata_ring_buffer_poll,
 781         .splice_read = lttng_metadata_ring_buffer_splice_read,
 782         .mmap = lttng_metadata_ring_buffer_mmap,
 783         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 784         .llseek = vfs_lib_ring_buffer_no_llseek,
 785 #ifdef CONFIG_COMPAT
 786         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 787 #endif
 788 };
 789
 790 static
 791 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 792                 const struct file_operations *fops)
 793 {
 794         int stream_fd, ret;
 795         struct file *stream_file;
 796
 797         stream_fd = lttng_get_unused_fd();
 798         if (stream_fd < 0) {
 799                 ret = stream_fd;
 800                 goto fd_error;
 801         }
 802         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 803                         stream_priv, O_RDWR);
 804         if (IS_ERR(stream_file)) {
 805                 ret = PTR_ERR(stream_file);
 806                 goto file_error;
 807         }
 808         /*
 809          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 810          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 811          * file descriptor, so we set FMODE_PREAD here.
 812          */
 813         stream_file->f_mode |= FMODE_PREAD;
 814         fd_install(stream_fd, stream_file);
 815         /*
 816          * The stream holds a reference to the channel within the generic ring
 817          * buffer library, so no need to hold a refcount on the channel and
 818          * session files here.
 819          */
 820         return stream_fd;
 821
 822 file_error:
 823         put_unused_fd(stream_fd);
 824 fd_error:
 825         return ret;
 826 }
 827
 828 static
 829 int lttng_abi_open_stream(struct file *channel_file)
 830 {
 831         struct lttng_channel *channel = channel_file->private_data;
 832         struct lib_ring_buffer *buf;
 833         int ret;
 834         void *stream_priv;
 835
 836         buf = channel->ops->buffer_read_open(channel->chan);
 837         if (!buf)
 838                 return -ENOENT;
 839
 840         stream_priv = buf;
 841         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 842                         &lttng_stream_ring_buffer_file_operations);
 843         if (ret < 0)
 844                 goto fd_error;
 845
 846         return ret;
 847
 848 fd_error:
 849         channel->ops->buffer_read_close(buf);
 850         return ret;
 851 }
 852
 853 static
 854 int lttng_abi_open_metadata_stream(struct file *channel_file)
 855 {
 856         struct lttng_channel *channel = channel_file->private_data;
 857         struct lttng_session *session = channel->session;
 858         struct lib_ring_buffer *buf;
 859         int ret;
 860         struct lttng_metadata_stream *metadata_stream;
 861         void *stream_priv;
 862
 863         buf = channel->ops->buffer_read_open(channel->chan);
 864         if (!buf)
 865                 return -ENOENT;
 866
 867         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 868                         GFP_KERNEL);
 869         if (!metadata_stream) {
 870                 ret = -ENOMEM;
 871                 goto nomem;
 872         }
 873         metadata_stream->metadata_cache = session->metadata_cache;
 874         init_waitqueue_head(&metadata_stream->read_wait);
 875         metadata_stream->priv = buf;
 876         stream_priv = metadata_stream;
 877         metadata_stream->transport = channel->transport;
 878         mutex_init(&metadata_stream->lock);
 879
 880         /*
 881          * Since life-time of metadata cache differs from that of
 882          * session, we need to keep our own reference on the transport.
 883          */
 884         if (!try_module_get(metadata_stream->transport->owner)) {
 885                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 886                 ret = -EINVAL;
 887                 goto notransport;
 888         }
 889
 890         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 891                         &lttng_metadata_ring_buffer_file_operations);
 892         if (ret < 0)
 893                 goto fd_error;
 894
 895         kref_get(&session->metadata_cache->refcount);
 896         list_add(&metadata_stream->list,
 897                 &session->metadata_cache->metadata_stream);
 898         return ret;
 899
 900 fd_error:
 901         module_put(metadata_stream->transport->owner);
 902 notransport:
 903         kfree(metadata_stream);
 904 nomem:
 905         channel->ops->buffer_read_close(buf);
 906         return ret;
 907 }
 908
 909 static
 910 int lttng_abi_create_event(struct file *channel_file,
 911                            struct lttng_kernel_event *event_param)
 912 {
 913         struct lttng_channel *channel = channel_file->private_data;
 914         int event_fd, ret;
 915         struct file *event_file;
 916         void *priv;
 917
 918         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 919         switch (event_param->instrumentation) {
 920         case LTTNG_KERNEL_KRETPROBE:
 921                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 922                 break;
 923         case LTTNG_KERNEL_KPROBE:
 924                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 925                 break;
 926         case LTTNG_KERNEL_FUNCTION:
 927                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 928                 break;
 929         default:
 930                 break;
 931         }
 932         event_fd = lttng_get_unused_fd();
 933         if (event_fd < 0) {
 934                 ret = event_fd;
 935                 goto fd_error;
 936         }
 937         event_file = anon_inode_getfile("[lttng_event]",
 938                                         &lttng_event_fops,
 939                                         NULL, O_RDWR);
 940         if (IS_ERR(event_file)) {
 941                 ret = PTR_ERR(event_file);
 942                 goto file_error;
 943         }
 944         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
 945                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
 946                 struct lttng_enabler *enabler;
 947
 948                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
 949                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
 950                                 event_param, channel);
 951                 } else {
 952                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
 953                                 event_param, channel);
 954                 }
 955                 priv = enabler;
 956         } else {
 957                 struct lttng_event *event;
 958
 959                 /*
 960                  * We tolerate no failure path after event creation. It
 961                  * will stay invariant for the rest of the session.
 962                  */
 963                 event = lttng_event_create(channel, event_param,
 964                                 NULL, NULL,
 965                                 event_param->instrumentation);
 966                 WARN_ON_ONCE(!event);
 967                 if (IS_ERR(event)) {
 968                         ret = PTR_ERR(event);
 969                         goto event_error;
 970                 }
 971                 priv = event;
 972         }
 973         event_file->private_data = priv;
 974         fd_install(event_fd, event_file);
 975         /* The event holds a reference on the channel */
 976         atomic_long_inc(&channel_file->f_count);
 977         return event_fd;
 978
 979 event_error:
 980         fput(event_file);
 981 file_error:
 982         put_unused_fd(event_fd);
 983 fd_error:
 984         return ret;
 985 }
 986
 987 /**
 988  *      lttng_channel_ioctl - lttng syscall through ioctl
 989  *
 990  *      @file: the file
 991  *      @cmd: the command
 992  *      @arg: command arg
 993  *
 994  *      This ioctl implements lttng commands:
 995  *      LTTNG_KERNEL_STREAM
 996  *              Returns an event stream file descriptor or failure.
 997  *              (typically, one event stream records events from one CPU)
 998  *      LTTNG_KERNEL_EVENT
 999  *              Returns an event file descriptor or failure.
1000  *      LTTNG_KERNEL_CONTEXT
1001  *              Prepend a context field to each event in the channel
1002  *      LTTNG_KERNEL_ENABLE
1003  *              Enable recording for events in this channel (weak enable)
1004  *      LTTNG_KERNEL_DISABLE
1005  *              Disable recording for events in this channel (strong disable)
1006  *
1007  * Channel and event file descriptors also hold a reference on the session.
1008  */
1009 static
1010 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1011 {
1012         struct lttng_channel *channel = file->private_data;
1013
1014         switch (cmd) {
1015         case LTTNG_KERNEL_OLD_STREAM:
1016         case LTTNG_KERNEL_STREAM:
1017                 return lttng_abi_open_stream(file);
1018         case LTTNG_KERNEL_OLD_EVENT:
1019         {
1020                 struct lttng_kernel_event *uevent_param;
1021                 struct lttng_kernel_old_event *old_uevent_param;
1022                 int ret;
1023
1024                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1025                                 GFP_KERNEL);
1026                 if (!uevent_param) {
1027                         ret = -ENOMEM;
1028                         goto old_event_end;
1029                 }
1030                 old_uevent_param = kmalloc(
1031                                 sizeof(struct lttng_kernel_old_event),
1032                                 GFP_KERNEL);
1033                 if (!old_uevent_param) {
1034                         ret = -ENOMEM;
1035                         goto old_event_error_free_param;
1036                 }
1037                 if (copy_from_user(old_uevent_param,
1038                                 (struct lttng_kernel_old_event __user *) arg,
1039                                 sizeof(struct lttng_kernel_old_event))) {
1040                         ret = -EFAULT;
1041                         goto old_event_error_free_old_param;
1042                 }
1043
1044                 memcpy(uevent_param->name, old_uevent_param->name,
1045                                 sizeof(uevent_param->name));
1046                 uevent_param->instrumentation =
1047                         old_uevent_param->instrumentation;
1048
1049                 switch (old_uevent_param->instrumentation) {
1050                 case LTTNG_KERNEL_KPROBE:
1051                         uevent_param->u.kprobe.addr =
1052                                 old_uevent_param->u.kprobe.addr;
1053                         uevent_param->u.kprobe.offset =
1054                                 old_uevent_param->u.kprobe.offset;
1055                         memcpy(uevent_param->u.kprobe.symbol_name,
1056                                 old_uevent_param->u.kprobe.symbol_name,
1057                                 sizeof(uevent_param->u.kprobe.symbol_name));
1058                         break;
1059                 case LTTNG_KERNEL_KRETPROBE:
1060                         uevent_param->u.kretprobe.addr =
1061                                 old_uevent_param->u.kretprobe.addr;
1062                         uevent_param->u.kretprobe.offset =
1063                                 old_uevent_param->u.kretprobe.offset;
1064                         memcpy(uevent_param->u.kretprobe.symbol_name,
1065                                 old_uevent_param->u.kretprobe.symbol_name,
1066                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1067                         break;
1068                 case LTTNG_KERNEL_FUNCTION:
1069                         memcpy(uevent_param->u.ftrace.symbol_name,
1070                                         old_uevent_param->u.ftrace.symbol_name,
1071                                         sizeof(uevent_param->u.ftrace.symbol_name));
1072                         break;
1073                 default:
1074                         break;
1075                 }
1076                 ret = lttng_abi_create_event(file, uevent_param);
1077
1078 old_event_error_free_old_param:
1079                 kfree(old_uevent_param);
1080 old_event_error_free_param:
1081                 kfree(uevent_param);
1082 old_event_end:
1083                 return ret;
1084         }
1085         case LTTNG_KERNEL_EVENT:
1086         {
1087                 struct lttng_kernel_event uevent_param;
1088
1089                 if (copy_from_user(&uevent_param,
1090                                 (struct lttng_kernel_event __user *) arg,
1091                                 sizeof(uevent_param)))
1092                         return -EFAULT;
1093                 return lttng_abi_create_event(file, &uevent_param);
1094         }
1095         case LTTNG_KERNEL_OLD_CONTEXT:
1096         {
1097                 struct lttng_kernel_context *ucontext_param;
1098                 struct lttng_kernel_old_context *old_ucontext_param;
1099                 int ret;
1100
1101                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1102                                 GFP_KERNEL);
1103                 if (!ucontext_param) {
1104                         ret = -ENOMEM;
1105                         goto old_ctx_end;
1106                 }
1107                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1108                                 GFP_KERNEL);
1109                 if (!old_ucontext_param) {
1110                         ret = -ENOMEM;
1111                         goto old_ctx_error_free_param;
1112                 }
1113
1114                 if (copy_from_user(old_ucontext_param,
1115                                 (struct lttng_kernel_old_context __user *) arg,
1116                                 sizeof(struct lttng_kernel_old_context))) {
1117                         ret = -EFAULT;
1118                         goto old_ctx_error_free_old_param;
1119                 }
1120                 ucontext_param->ctx = old_ucontext_param->ctx;
1121                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1122                                 sizeof(ucontext_param->padding));
1123                 /* only type that uses the union */
1124                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1125                         ucontext_param->u.perf_counter.type =
1126                                 old_ucontext_param->u.perf_counter.type;
1127                         ucontext_param->u.perf_counter.config =
1128                                 old_ucontext_param->u.perf_counter.config;
1129                         memcpy(ucontext_param->u.perf_counter.name,
1130                                 old_ucontext_param->u.perf_counter.name,
1131                                 sizeof(ucontext_param->u.perf_counter.name));
1132                 }
1133
1134                 ret = lttng_abi_add_context(file,
1135                                 ucontext_param,
1136                                 &channel->ctx, channel->session);
1137
1138 old_ctx_error_free_old_param:
1139                 kfree(old_ucontext_param);
1140 old_ctx_error_free_param:
1141                 kfree(ucontext_param);
1142 old_ctx_end:
1143                 return ret;
1144         }
1145         case LTTNG_KERNEL_CONTEXT:
1146         {
1147                 struct lttng_kernel_context ucontext_param;
1148
1149                 if (copy_from_user(&ucontext_param,
1150                                 (struct lttng_kernel_context __user *) arg,
1151                                 sizeof(ucontext_param)))
1152                         return -EFAULT;
1153                 return lttng_abi_add_context(file,
1154                                 &ucontext_param,
1155                                 &channel->ctx, channel->session);
1156         }
1157         case LTTNG_KERNEL_OLD_ENABLE:
1158         case LTTNG_KERNEL_ENABLE:
1159                 return lttng_channel_enable(channel);
1160         case LTTNG_KERNEL_OLD_DISABLE:
1161         case LTTNG_KERNEL_DISABLE:
1162                 return lttng_channel_disable(channel);
1163         case LTTNG_KERNEL_SYSCALL_MASK:
1164                 return lttng_channel_syscall_mask(channel,
1165                         (struct lttng_kernel_syscall_mask __user *) arg);
1166         default:
1167                 return -ENOIOCTLCMD;
1168         }
1169
1170 }
1171
1172 /**
1173  *      lttng_metadata_ioctl - lttng syscall through ioctl
1174  *
1175  *      @file: the file
1176  *      @cmd: the command
1177  *      @arg: command arg
1178  *
1179  *      This ioctl implements lttng commands:
1180  *      LTTNG_KERNEL_STREAM
1181  *              Returns an event stream file descriptor or failure.
1182  *
1183  * Channel and event file descriptors also hold a reference on the session.
1184  */
1185 static
1186 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1187 {
1188         switch (cmd) {
1189         case LTTNG_KERNEL_OLD_STREAM:
1190         case LTTNG_KERNEL_STREAM:
1191                 return lttng_abi_open_metadata_stream(file);
1192         default:
1193                 return -ENOIOCTLCMD;
1194         }
1195 }
1196
1197 /**
1198  *      lttng_channel_poll - lttng stream addition/removal monitoring
1199  *
1200  *      @file: the file
1201  *      @wait: poll table
1202  */
1203 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1204 {
1205         struct lttng_channel *channel = file->private_data;
1206         unsigned int mask = 0;
1207
1208         if (file->f_mode & FMODE_READ) {
1209                 poll_wait_set_exclusive(wait);
1210                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1211                           wait);
1212
1213                 if (channel->ops->is_disabled(channel->chan))
1214                         return POLLERR;
1215                 if (channel->ops->is_finalized(channel->chan))
1216                         return POLLHUP;
1217                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1218                         return POLLIN | POLLRDNORM;
1219                 return 0;
1220         }
1221         return mask;
1222
1223 }
1224
1225 static
1226 int lttng_channel_release(struct inode *inode, struct file *file)
1227 {
1228         struct lttng_channel *channel = file->private_data;
1229
1230         if (channel)
1231                 fput(channel->session->file);
1232         return 0;
1233 }
1234
1235 static
1236 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1237 {
1238         struct lttng_channel *channel = file->private_data;
1239
1240         if (channel) {
1241                 lttng_metadata_channel_destroy(channel);
1242                 fput(channel->session->file);
1243         }
1244
1245         return 0;
1246 }
1247
1248 static const struct file_operations lttng_channel_fops = {
1249         .owner = THIS_MODULE,
1250         .release = lttng_channel_release,
1251         .poll = lttng_channel_poll,
1252         .unlocked_ioctl = lttng_channel_ioctl,
1253 #ifdef CONFIG_COMPAT
1254         .compat_ioctl = lttng_channel_ioctl,
1255 #endif
1256 };
1257
1258 static const struct file_operations lttng_metadata_fops = {
1259         .owner = THIS_MODULE,
1260         .release = lttng_metadata_channel_release,
1261         .unlocked_ioctl = lttng_metadata_ioctl,
1262 #ifdef CONFIG_COMPAT
1263         .compat_ioctl = lttng_metadata_ioctl,
1264 #endif
1265 };
1266
1267 /**
1268  *      lttng_event_ioctl - lttng syscall through ioctl
1269  *
1270  *      @file: the file
1271  *      @cmd: the command
1272  *      @arg: command arg
1273  *
1274  *      This ioctl implements lttng commands:
1275  *      LTTNG_KERNEL_CONTEXT
1276  *              Prepend a context field to each record of this event
1277  *      LTTNG_KERNEL_ENABLE
1278  *              Enable recording for this event (weak enable)
1279  *      LTTNG_KERNEL_DISABLE
1280  *              Disable recording for this event (strong disable)
1281  */
1282 static
1283 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1284 {
1285         struct lttng_event *event;
1286         struct lttng_enabler *enabler;
1287         enum lttng_event_type *evtype = file->private_data;
1288
1289         switch (cmd) {
1290         case LTTNG_KERNEL_OLD_CONTEXT:
1291         {
1292                 /* Not implemented */
1293                 return -ENOSYS;
1294         }
1295         case LTTNG_KERNEL_CONTEXT:
1296         {
1297                 /* Not implemented */
1298                 return -ENOSYS;
1299         }
1300         case LTTNG_KERNEL_OLD_ENABLE:
1301         case LTTNG_KERNEL_ENABLE:
1302                 switch (*evtype) {
1303                 case LTTNG_TYPE_EVENT:
1304                         event = file->private_data;
1305                         return lttng_event_enable(event);
1306                 case LTTNG_TYPE_ENABLER:
1307                         enabler = file->private_data;
1308                         return lttng_enabler_enable(enabler);
1309                 default:
1310                         WARN_ON_ONCE(1);
1311                         return -ENOSYS;
1312                 }
1313         case LTTNG_KERNEL_OLD_DISABLE:
1314         case LTTNG_KERNEL_DISABLE:
1315                 switch (*evtype) {
1316                 case LTTNG_TYPE_EVENT:
1317                         event = file->private_data;
1318                         return lttng_event_disable(event);
1319                 case LTTNG_TYPE_ENABLER:
1320                         enabler = file->private_data;
1321                         return lttng_enabler_disable(enabler);
1322                 default:
1323                         WARN_ON_ONCE(1);
1324                         return -ENOSYS;
1325                 }
1326         default:
1327                 return -ENOIOCTLCMD;
1328         }
1329 }
1330
1331 static
1332 int lttng_event_release(struct inode *inode, struct file *file)
1333 {
1334         struct lttng_event *event;
1335         struct lttng_enabler *enabler;
1336         enum lttng_event_type *evtype = file->private_data;
1337
1338         if (!evtype)
1339                 return 0;
1340
1341         switch (*evtype) {
1342         case LTTNG_TYPE_EVENT:
1343                 event = file->private_data;
1344                 if (event)
1345                         fput(event->chan->file);
1346                 break;
1347         case LTTNG_TYPE_ENABLER:
1348                 enabler = file->private_data;
1349                 if (enabler)
1350                         fput(enabler->chan->file);
1351                 break;
1352         default:
1353                 WARN_ON_ONCE(1);
1354                 break;
1355         }
1356
1357         return 0;
1358 }
1359
1360 /* TODO: filter control ioctl */
1361 static const struct file_operations lttng_event_fops = {
1362         .owner = THIS_MODULE,
1363         .release = lttng_event_release,
1364         .unlocked_ioctl = lttng_event_ioctl,
1365 #ifdef CONFIG_COMPAT
1366         .compat_ioctl = lttng_event_ioctl,
1367 #endif
1368 };
1369
1370 static int put_u64(uint64_t val, unsigned long arg)
1371 {
1372         return put_user(val, (uint64_t __user *) arg);
1373 }
1374
1375 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1376                 unsigned int cmd, unsigned long arg)
1377 {
1378         struct lib_ring_buffer *buf = filp->private_data;
1379         struct channel *chan = buf->backend.chan;
1380         const struct lib_ring_buffer_config *config = &chan->backend.config;
1381         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1382         int ret;
1383
1384         if (atomic_read(&chan->record_disabled))
1385                 return -EIO;
1386
1387         switch (cmd) {
1388         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1389         {
1390                 uint64_t ts;
1391
1392                 ret = ops->timestamp_begin(config, buf, &ts);
1393                 if (ret < 0)
1394                         goto error;
1395                 return put_u64(ts, arg);
1396         }
1397         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1398         {
1399                 uint64_t ts;
1400
1401                 ret = ops->timestamp_end(config, buf, &ts);
1402                 if (ret < 0)
1403                         goto error;
1404                 return put_u64(ts, arg);
1405         }
1406         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1407         {
1408                 uint64_t ed;
1409
1410                 ret = ops->events_discarded(config, buf, &ed);
1411                 if (ret < 0)
1412                         goto error;
1413                 return put_u64(ed, arg);
1414         }
1415         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1416         {
1417                 uint64_t cs;
1418
1419                 ret = ops->content_size(config, buf, &cs);
1420                 if (ret < 0)
1421                         goto error;
1422                 return put_u64(cs, arg);
1423         }
1424         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1425         {
1426                 uint64_t ps;
1427
1428                 ret = ops->packet_size(config, buf, &ps);
1429                 if (ret < 0)
1430                         goto error;
1431                 return put_u64(ps, arg);
1432         }
1433         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1434         {
1435                 uint64_t si;
1436
1437                 ret = ops->stream_id(config, buf, &si);
1438                 if (ret < 0)
1439                         goto error;
1440                 return put_u64(si, arg);
1441         }
1442         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1443         {
1444                 uint64_t ts;
1445
1446                 ret = ops->current_timestamp(config, buf, &ts);
1447                 if (ret < 0)
1448                         goto error;
1449                 return put_u64(ts, arg);
1450         }
1451         default:
1452                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1453                                 cmd, arg);
1454         }
1455
1456 error:
1457         return -ENOSYS;
1458 }
1459
1460 #ifdef CONFIG_COMPAT
1461 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1462                 unsigned int cmd, unsigned long arg)
1463 {
1464         struct lib_ring_buffer *buf = filp->private_data;
1465         struct channel *chan = buf->backend.chan;
1466         const struct lib_ring_buffer_config *config = &chan->backend.config;
1467         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1468         int ret;
1469
1470         if (atomic_read(&chan->record_disabled))
1471                 return -EIO;
1472
1473         switch (cmd) {
1474         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1475         {
1476                 uint64_t ts;
1477
1478                 ret = ops->timestamp_begin(config, buf, &ts);
1479                 if (ret < 0)
1480                         goto error;
1481                 return put_u64(ts, arg);
1482         }
1483         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1484         {
1485                 uint64_t ts;
1486
1487                 ret = ops->timestamp_end(config, buf, &ts);
1488                 if (ret < 0)
1489                         goto error;
1490                 return put_u64(ts, arg);
1491         }
1492         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1493         {
1494                 uint64_t ed;
1495
1496                 ret = ops->events_discarded(config, buf, &ed);
1497                 if (ret < 0)
1498                         goto error;
1499                 return put_u64(ed, arg);
1500         }
1501         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1502         {
1503                 uint64_t cs;
1504
1505                 ret = ops->content_size(config, buf, &cs);
1506                 if (ret < 0)
1507                         goto error;
1508                 return put_u64(cs, arg);
1509         }
1510         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1511         {
1512                 uint64_t ps;
1513
1514                 ret = ops->packet_size(config, buf, &ps);
1515                 if (ret < 0)
1516                         goto error;
1517                 return put_u64(ps, arg);
1518         }
1519         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1520         {
1521                 uint64_t si;
1522
1523                 ret = ops->stream_id(config, buf, &si);
1524                 if (ret < 0)
1525                         goto error;
1526                 return put_u64(si, arg);
1527         }
1528         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1529         {
1530                 uint64_t ts;
1531
1532                 ret = ops->current_timestamp(config, buf, &ts);
1533                 if (ret < 0)
1534                         goto error;
1535                 return put_u64(ts, arg);
1536         }
1537         default:
1538                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1539                                 cmd, arg);
1540         }
1541
1542 error:
1543         return -ENOSYS;
1544 }
1545 #endif /* CONFIG_COMPAT */
1546
1547 static void lttng_stream_override_ring_buffer_fops(void)
1548 {
1549         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1550         lttng_stream_ring_buffer_file_operations.open =
1551                 lib_ring_buffer_file_operations.open;
1552         lttng_stream_ring_buffer_file_operations.release =
1553                 lib_ring_buffer_file_operations.release;
1554         lttng_stream_ring_buffer_file_operations.poll =
1555                 lib_ring_buffer_file_operations.poll;
1556         lttng_stream_ring_buffer_file_operations.splice_read =
1557                 lib_ring_buffer_file_operations.splice_read;
1558         lttng_stream_ring_buffer_file_operations.mmap =
1559                 lib_ring_buffer_file_operations.mmap;
1560         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1561                 lttng_stream_ring_buffer_ioctl;
1562         lttng_stream_ring_buffer_file_operations.llseek =
1563                 lib_ring_buffer_file_operations.llseek;
1564 #ifdef CONFIG_COMPAT
1565         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1566                 lttng_stream_ring_buffer_compat_ioctl;
1567 #endif
1568 }
1569
1570 int __init lttng_abi_init(void)
1571 {
1572         int ret = 0;
1573
1574         wrapper_vmalloc_sync_all();
1575         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1576                                         &lttng_fops, NULL);
1577
1578         if (!lttng_proc_dentry) {
1579                 printk(KERN_ERR "Error creating LTTng control file\n");
1580                 ret = -ENOMEM;
1581                 goto error;
1582         }
1583         lttng_stream_override_ring_buffer_fops();
1584
1585 error:
1586         return ret;
1587 }
1588
1589 /* No __exit annotation because used by init error path too. */
1590 void lttng_abi_exit(void)
1591 {
1592         if (lttng_proc_dentry)
1593                 remove_proc_entry("lttng", NULL);
1594 }