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         default:
 514                 return -ENOIOCTLCMD;
 515         }
 516 }
 517
 518 /*
 519  * Called when the last file reference is dropped.
 520  *
 521  * Big fat note: channels and events are invariant for the whole session after
 522  * their creation. So this session destruction also destroys all channel and
 523  * event structures specific to this session (they are not destroyed when their
 524  * individual file is released).
 525  */
 526 static
 527 int lttng_session_release(struct inode *inode, struct file *file)
 528 {
 529         struct lttng_session *session = file->private_data;
 530
 531         if (session)
 532                 lttng_session_destroy(session);
 533         return 0;
 534 }
 535
 536 static const struct file_operations lttng_session_fops = {
 537         .owner = THIS_MODULE,
 538         .release = lttng_session_release,
 539         .unlocked_ioctl = lttng_session_ioctl,
 540 #ifdef CONFIG_COMPAT
 541         .compat_ioctl = lttng_session_ioctl,
 542 #endif
 543 };
 544
 545 /**
 546  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 547  *      @filp: the file
 548  *      @wait: poll table
 549  *
 550  *      Handles the poll operations for the metadata channels.
 551  */
 552 static
 553 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 554                 poll_table *wait)
 555 {
 556         struct lttng_metadata_stream *stream = filp->private_data;
 557         struct lib_ring_buffer *buf = stream->priv;
 558         int finalized;
 559         unsigned int mask = 0;
 560
 561         if (filp->f_mode & FMODE_READ) {
 562                 poll_wait_set_exclusive(wait);
 563                 poll_wait(filp, &stream->read_wait, wait);
 564
 565                 finalized = stream->finalized;
 566
 567                 /*
 568                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 569                  * ordering finalized load before offsets loads.
 570                  */
 571                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 572
 573                 if (finalized)
 574                         mask |= POLLHUP;
 575
 576                 if (stream->metadata_cache->metadata_written >
 577                                 stream->metadata_out)
 578                         mask |= POLLIN;
 579         }
 580
 581         return mask;
 582 }
 583
 584 static
 585 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 586                 unsigned int cmd, unsigned long arg)
 587 {
 588         struct lttng_metadata_stream *stream = filp->private_data;
 589
 590         stream->metadata_out = stream->metadata_in;
 591 }
 592
 593 static
 594 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 595                 unsigned int cmd, unsigned long arg)
 596 {
 597         int ret;
 598         struct lttng_metadata_stream *stream = filp->private_data;
 599         struct lib_ring_buffer *buf = stream->priv;
 600
 601         switch (cmd) {
 602         case RING_BUFFER_GET_NEXT_SUBBUF:
 603         {
 604                 struct lttng_metadata_stream *stream = filp->private_data;
 605                 struct lib_ring_buffer *buf = stream->priv;
 606                 struct channel *chan = buf->backend.chan;
 607
 608                 ret = lttng_metadata_output_channel(stream, chan);
 609                 if (ret > 0) {
 610                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 611                         ret = 0;
 612                 } else if (ret < 0)
 613                         goto err;
 614                 break;
 615         }
 616         case RING_BUFFER_GET_SUBBUF:
 617         {
 618                 /*
 619                  * Random access is not allowed for metadata channel.
 620                  */
 621                 return -ENOSYS;
 622         }
 623         case RING_BUFFER_FLUSH:
 624         {
 625                 struct lttng_metadata_stream *stream = filp->private_data;
 626                 struct lib_ring_buffer *buf = stream->priv;
 627                 struct channel *chan = buf->backend.chan;
 628
 629                 /*
 630                  * Before doing the actual ring buffer flush, write up to one
 631                  * packet of metadata in the ring buffer.
 632                  */
 633                 ret = lttng_metadata_output_channel(stream, chan);
 634                 if (ret < 0)
 635                         goto err;
 636                 break;
 637         }
 638         default:
 639                 break;
 640         }
 641         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 642
 643         /* Performing lib ring buffer ioctl after our own. */
 644         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 645         if (ret < 0)
 646                 goto err;
 647
 648         switch (cmd) {
 649         case RING_BUFFER_PUT_NEXT_SUBBUF:
 650         {
 651                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 652                                 cmd, arg);
 653                 break;
 654         }
 655         default:
 656                 break;
 657         }
 658 err:
 659         return ret;
 660 }
 661
 662 #ifdef CONFIG_COMPAT
 663 static
 664 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 665                 unsigned int cmd, unsigned long arg)
 666 {
 667         int ret;
 668         struct lttng_metadata_stream *stream = filp->private_data;
 669         struct lib_ring_buffer *buf = stream->priv;
 670
 671         switch (cmd) {
 672         case RING_BUFFER_GET_NEXT_SUBBUF:
 673         {
 674                 struct lttng_metadata_stream *stream = filp->private_data;
 675                 struct lib_ring_buffer *buf = stream->priv;
 676                 struct channel *chan = buf->backend.chan;
 677
 678                 ret = lttng_metadata_output_channel(stream, chan);
 679                 if (ret > 0) {
 680                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 681                         ret = 0;
 682                 } else if (ret < 0)
 683                         goto err;
 684                 break;
 685         }
 686         case RING_BUFFER_GET_SUBBUF:
 687         {
 688                 /*
 689                  * Random access is not allowed for metadata channel.
 690                  */
 691                 return -ENOSYS;
 692         }
 693         default:
 694                 break;
 695         }
 696         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 697
 698         /* Performing lib ring buffer ioctl after our own. */
 699         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 700         if (ret < 0)
 701                 goto err;
 702
 703         switch (cmd) {
 704         case RING_BUFFER_PUT_NEXT_SUBBUF:
 705         {
 706                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 707                                 cmd, arg);
 708                 break;
 709         }
 710         default:
 711                 break;
 712         }
 713 err:
 714         return ret;
 715 }
 716 #endif
 717
 718 /*
 719  * This is not used by anonymous file descriptors. This code is left
 720  * there if we ever want to implement an inode with open() operation.
 721  */
 722 static
 723 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 724 {
 725         struct lttng_metadata_stream *stream = inode->i_private;
 726         struct lib_ring_buffer *buf = stream->priv;
 727
 728         file->private_data = buf;
 729         /*
 730          * Since life-time of metadata cache differs from that of
 731          * session, we need to keep our own reference on the transport.
 732          */
 733         if (!try_module_get(stream->transport->owner)) {
 734                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 735                 return -EBUSY;
 736         }
 737         return lib_ring_buffer_open(inode, file, buf);
 738 }
 739
 740 static
 741 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 742 {
 743         struct lttng_metadata_stream *stream = file->private_data;
 744         struct lib_ring_buffer *buf = stream->priv;
 745
 746         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 747         module_put(stream->transport->owner);
 748         return lib_ring_buffer_release(inode, file, buf);
 749 }
 750
 751 static
 752 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 753                 struct pipe_inode_info *pipe, size_t len,
 754                 unsigned int flags)
 755 {
 756         struct lttng_metadata_stream *stream = in->private_data;
 757         struct lib_ring_buffer *buf = stream->priv;
 758
 759         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 760                         flags, buf);
 761 }
 762
 763 static
 764 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 765                 struct vm_area_struct *vma)
 766 {
 767         struct lttng_metadata_stream *stream = filp->private_data;
 768         struct lib_ring_buffer *buf = stream->priv;
 769
 770         return lib_ring_buffer_mmap(filp, vma, buf);
 771 }
 772
 773 static
 774 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 775         .owner = THIS_MODULE,
 776         .open = lttng_metadata_ring_buffer_open,
 777         .release = lttng_metadata_ring_buffer_release,
 778         .poll = lttng_metadata_ring_buffer_poll,
 779         .splice_read = lttng_metadata_ring_buffer_splice_read,
 780         .mmap = lttng_metadata_ring_buffer_mmap,
 781         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 782         .llseek = vfs_lib_ring_buffer_no_llseek,
 783 #ifdef CONFIG_COMPAT
 784         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 785 #endif
 786 };
 787
 788 static
 789 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 790                 const struct file_operations *fops)
 791 {
 792         int stream_fd, ret;
 793         struct file *stream_file;
 794
 795         stream_fd = lttng_get_unused_fd();
 796         if (stream_fd < 0) {
 797                 ret = stream_fd;
 798                 goto fd_error;
 799         }
 800         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 801                         stream_priv, O_RDWR);
 802         if (IS_ERR(stream_file)) {
 803                 ret = PTR_ERR(stream_file);
 804                 goto file_error;
 805         }
 806         /*
 807          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 808          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 809          * file descriptor, so we set FMODE_PREAD here.
 810          */
 811         stream_file->f_mode |= FMODE_PREAD;
 812         fd_install(stream_fd, stream_file);
 813         /*
 814          * The stream holds a reference to the channel within the generic ring
 815          * buffer library, so no need to hold a refcount on the channel and
 816          * session files here.
 817          */
 818         return stream_fd;
 819
 820 file_error:
 821         put_unused_fd(stream_fd);
 822 fd_error:
 823         return ret;
 824 }
 825
 826 static
 827 int lttng_abi_open_stream(struct file *channel_file)
 828 {
 829         struct lttng_channel *channel = channel_file->private_data;
 830         struct lib_ring_buffer *buf;
 831         int ret;
 832         void *stream_priv;
 833
 834         buf = channel->ops->buffer_read_open(channel->chan);
 835         if (!buf)
 836                 return -ENOENT;
 837
 838         stream_priv = buf;
 839         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 840                         &lttng_stream_ring_buffer_file_operations);
 841         if (ret < 0)
 842                 goto fd_error;
 843
 844         return ret;
 845
 846 fd_error:
 847         channel->ops->buffer_read_close(buf);
 848         return ret;
 849 }
 850
 851 static
 852 int lttng_abi_open_metadata_stream(struct file *channel_file)
 853 {
 854         struct lttng_channel *channel = channel_file->private_data;
 855         struct lttng_session *session = channel->session;
 856         struct lib_ring_buffer *buf;
 857         int ret;
 858         struct lttng_metadata_stream *metadata_stream;
 859         void *stream_priv;
 860
 861         buf = channel->ops->buffer_read_open(channel->chan);
 862         if (!buf)
 863                 return -ENOENT;
 864
 865         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 866                         GFP_KERNEL);
 867         if (!metadata_stream) {
 868                 ret = -ENOMEM;
 869                 goto nomem;
 870         }
 871         metadata_stream->metadata_cache = session->metadata_cache;
 872         init_waitqueue_head(&metadata_stream->read_wait);
 873         metadata_stream->priv = buf;
 874         stream_priv = metadata_stream;
 875         metadata_stream->transport = channel->transport;
 876         mutex_init(&metadata_stream->lock);
 877
 878         /*
 879          * Since life-time of metadata cache differs from that of
 880          * session, we need to keep our own reference on the transport.
 881          */
 882         if (!try_module_get(metadata_stream->transport->owner)) {
 883                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 884                 ret = -EINVAL;
 885                 goto notransport;
 886         }
 887
 888         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 889                         &lttng_metadata_ring_buffer_file_operations);
 890         if (ret < 0)
 891                 goto fd_error;
 892
 893         kref_get(&session->metadata_cache->refcount);
 894         list_add(&metadata_stream->list,
 895                 &session->metadata_cache->metadata_stream);
 896         return ret;
 897
 898 fd_error:
 899         module_put(metadata_stream->transport->owner);
 900 notransport:
 901         kfree(metadata_stream);
 902 nomem:
 903         channel->ops->buffer_read_close(buf);
 904         return ret;
 905 }
 906
 907 static
 908 int lttng_abi_create_event(struct file *channel_file,
 909                            struct lttng_kernel_event *event_param)
 910 {
 911         struct lttng_channel *channel = channel_file->private_data;
 912         struct lttng_event *event;
 913         int event_fd, ret;
 914         struct file *event_file;
 915
 916         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 917         switch (event_param->instrumentation) {
 918         case LTTNG_KERNEL_KRETPROBE:
 919                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 920                 break;
 921         case LTTNG_KERNEL_KPROBE:
 922                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 923                 break;
 924         case LTTNG_KERNEL_FUNCTION:
 925                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 926                 break;
 927         default:
 928                 break;
 929         }
 930         switch (event_param->instrumentation) {
 931         default:
 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                 /*
 945                  * We tolerate no failure path after event creation. It
 946                  * will stay invariant for the rest of the session.
 947                  */
 948                 event = lttng_event_create(channel, event_param, NULL, NULL);
 949                 WARN_ON_ONCE(!event);
 950                 if (IS_ERR(event)) {
 951                         ret = PTR_ERR(event);
 952                         goto event_error;
 953                 }
 954                 event_file->private_data = event;
 955                 fd_install(event_fd, event_file);
 956                 /* The event holds a reference on the channel */
 957                 atomic_long_inc(&channel_file->f_count);
 958                 break;
 959         case LTTNG_KERNEL_SYSCALL:
 960                 ret = lttng_syscalls_register(channel, NULL);
 961                 if (ret)
 962                         goto fd_error;
 963                 event_fd = 0;
 964                 if (event_param->u.syscall.enable) {
 965                         ret = lttng_syscall_filter_enable(channel,
 966                                 event_param->name[0] == '\0' ?
 967                                         NULL : event_param->name);
 968                         if (ret)
 969                                 goto fd_error;
 970
 971                 } else {
 972                         ret = lttng_syscall_filter_disable(channel,
 973                                 event_param->name[0] == '\0' ?
 974                                         NULL : event_param->name);
 975                         if (ret)
 976                                 goto fd_error;
 977                 }
 978                 break;
 979         }
 980         return event_fd;
 981
 982 event_error:
 983         fput(event_file);
 984 file_error:
 985         put_unused_fd(event_fd);
 986 fd_error:
 987         return ret;
 988 }
 989
 990 /**
 991  *      lttng_channel_ioctl - lttng syscall through ioctl
 992  *
 993  *      @file: the file
 994  *      @cmd: the command
 995  *      @arg: command arg
 996  *
 997  *      This ioctl implements lttng commands:
 998  *      LTTNG_KERNEL_STREAM
 999  *              Returns an event stream file descriptor or failure.
1000  *              (typically, one event stream records events from one CPU)
1001  *      LTTNG_KERNEL_EVENT
1002  *              Returns an event file descriptor or failure.
1003  *      LTTNG_KERNEL_CONTEXT
1004  *              Prepend a context field to each event in the channel
1005  *      LTTNG_KERNEL_ENABLE
1006  *              Enable recording for events in this channel (weak enable)
1007  *      LTTNG_KERNEL_DISABLE
1008  *              Disable recording for events in this channel (strong disable)
1009  *
1010  * Channel and event file descriptors also hold a reference on the session.
1011  */
1012 static
1013 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1014 {
1015         struct lttng_channel *channel = file->private_data;
1016
1017         switch (cmd) {
1018         case LTTNG_KERNEL_OLD_STREAM:
1019         case LTTNG_KERNEL_STREAM:
1020                 return lttng_abi_open_stream(file);
1021         case LTTNG_KERNEL_OLD_EVENT:
1022         {
1023                 struct lttng_kernel_event *uevent_param;
1024                 struct lttng_kernel_old_event *old_uevent_param;
1025                 int ret;
1026
1027                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1028                                 GFP_KERNEL);
1029                 if (!uevent_param) {
1030                         ret = -ENOMEM;
1031                         goto old_event_end;
1032                 }
1033                 old_uevent_param = kmalloc(
1034                                 sizeof(struct lttng_kernel_old_event),
1035                                 GFP_KERNEL);
1036                 if (!old_uevent_param) {
1037                         ret = -ENOMEM;
1038                         goto old_event_error_free_param;
1039                 }
1040                 if (copy_from_user(old_uevent_param,
1041                                 (struct lttng_kernel_old_event __user *) arg,
1042                                 sizeof(struct lttng_kernel_old_event))) {
1043                         ret = -EFAULT;
1044                         goto old_event_error_free_old_param;
1045                 }
1046
1047                 memcpy(uevent_param->name, old_uevent_param->name,
1048                                 sizeof(uevent_param->name));
1049                 uevent_param->instrumentation =
1050                         old_uevent_param->instrumentation;
1051
1052                 switch (old_uevent_param->instrumentation) {
1053                 case LTTNG_KERNEL_KPROBE:
1054                         uevent_param->u.kprobe.addr =
1055                                 old_uevent_param->u.kprobe.addr;
1056                         uevent_param->u.kprobe.offset =
1057                                 old_uevent_param->u.kprobe.offset;
1058                         memcpy(uevent_param->u.kprobe.symbol_name,
1059                                 old_uevent_param->u.kprobe.symbol_name,
1060                                 sizeof(uevent_param->u.kprobe.symbol_name));
1061                         break;
1062                 case LTTNG_KERNEL_KRETPROBE:
1063                         uevent_param->u.kretprobe.addr =
1064                                 old_uevent_param->u.kretprobe.addr;
1065                         uevent_param->u.kretprobe.offset =
1066                                 old_uevent_param->u.kretprobe.offset;
1067                         memcpy(uevent_param->u.kretprobe.symbol_name,
1068                                 old_uevent_param->u.kretprobe.symbol_name,
1069                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1070                         break;
1071                 case LTTNG_KERNEL_FUNCTION:
1072                         memcpy(uevent_param->u.ftrace.symbol_name,
1073                                         old_uevent_param->u.ftrace.symbol_name,
1074                                         sizeof(uevent_param->u.ftrace.symbol_name));
1075                         break;
1076                 default:
1077                         break;
1078                 }
1079                 ret = lttng_abi_create_event(file, uevent_param);
1080
1081 old_event_error_free_old_param:
1082                 kfree(old_uevent_param);
1083 old_event_error_free_param:
1084                 kfree(uevent_param);
1085 old_event_end:
1086                 return ret;
1087         }
1088         case LTTNG_KERNEL_EVENT:
1089         {
1090                 struct lttng_kernel_event uevent_param;
1091
1092                 if (copy_from_user(&uevent_param,
1093                                 (struct lttng_kernel_event __user *) arg,
1094                                 sizeof(uevent_param)))
1095                         return -EFAULT;
1096                 return lttng_abi_create_event(file, &uevent_param);
1097         }
1098         case LTTNG_KERNEL_OLD_CONTEXT:
1099         {
1100                 struct lttng_kernel_context *ucontext_param;
1101                 struct lttng_kernel_old_context *old_ucontext_param;
1102                 int ret;
1103
1104                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1105                                 GFP_KERNEL);
1106                 if (!ucontext_param) {
1107                         ret = -ENOMEM;
1108                         goto old_ctx_end;
1109                 }
1110                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1111                                 GFP_KERNEL);
1112                 if (!old_ucontext_param) {
1113                         ret = -ENOMEM;
1114                         goto old_ctx_error_free_param;
1115                 }
1116
1117                 if (copy_from_user(old_ucontext_param,
1118                                 (struct lttng_kernel_old_context __user *) arg,
1119                                 sizeof(struct lttng_kernel_old_context))) {
1120                         ret = -EFAULT;
1121                         goto old_ctx_error_free_old_param;
1122                 }
1123                 ucontext_param->ctx = old_ucontext_param->ctx;
1124                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1125                                 sizeof(ucontext_param->padding));
1126                 /* only type that uses the union */
1127                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1128                         ucontext_param->u.perf_counter.type =
1129                                 old_ucontext_param->u.perf_counter.type;
1130                         ucontext_param->u.perf_counter.config =
1131                                 old_ucontext_param->u.perf_counter.config;
1132                         memcpy(ucontext_param->u.perf_counter.name,
1133                                 old_ucontext_param->u.perf_counter.name,
1134                                 sizeof(ucontext_param->u.perf_counter.name));
1135                 }
1136
1137                 ret = lttng_abi_add_context(file,
1138                                 ucontext_param,
1139                                 &channel->ctx, channel->session);
1140
1141 old_ctx_error_free_old_param:
1142                 kfree(old_ucontext_param);
1143 old_ctx_error_free_param:
1144                 kfree(ucontext_param);
1145 old_ctx_end:
1146                 return ret;
1147         }
1148         case LTTNG_KERNEL_CONTEXT:
1149         {
1150                 struct lttng_kernel_context ucontext_param;
1151
1152                 if (copy_from_user(&ucontext_param,
1153                                 (struct lttng_kernel_context __user *) arg,
1154                                 sizeof(ucontext_param)))
1155                         return -EFAULT;
1156                 return lttng_abi_add_context(file,
1157                                 &ucontext_param,
1158                                 &channel->ctx, channel->session);
1159         }
1160         case LTTNG_KERNEL_OLD_ENABLE:
1161         case LTTNG_KERNEL_ENABLE:
1162                 return lttng_channel_enable(channel);
1163         case LTTNG_KERNEL_OLD_DISABLE:
1164         case LTTNG_KERNEL_DISABLE:
1165                 return lttng_channel_disable(channel);
1166         case LTTNG_KERNEL_SYSCALL_MASK:
1167                 return lttng_channel_syscall_mask(channel,
1168                         (struct lttng_kernel_syscall_mask __user *) arg);
1169         default:
1170                 return -ENOIOCTLCMD;
1171         }
1172
1173 }
1174
1175 /**
1176  *      lttng_metadata_ioctl - lttng syscall through ioctl
1177  *
1178  *      @file: the file
1179  *      @cmd: the command
1180  *      @arg: command arg
1181  *
1182  *      This ioctl implements lttng commands:
1183  *      LTTNG_KERNEL_STREAM
1184  *              Returns an event stream file descriptor or failure.
1185  *
1186  * Channel and event file descriptors also hold a reference on the session.
1187  */
1188 static
1189 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1190 {
1191         switch (cmd) {
1192         case LTTNG_KERNEL_OLD_STREAM:
1193         case LTTNG_KERNEL_STREAM:
1194                 return lttng_abi_open_metadata_stream(file);
1195         default:
1196                 return -ENOIOCTLCMD;
1197         }
1198 }
1199
1200 /**
1201  *      lttng_channel_poll - lttng stream addition/removal monitoring
1202  *
1203  *      @file: the file
1204  *      @wait: poll table
1205  */
1206 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1207 {
1208         struct lttng_channel *channel = file->private_data;
1209         unsigned int mask = 0;
1210
1211         if (file->f_mode & FMODE_READ) {
1212                 poll_wait_set_exclusive(wait);
1213                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1214                           wait);
1215
1216                 if (channel->ops->is_disabled(channel->chan))
1217                         return POLLERR;
1218                 if (channel->ops->is_finalized(channel->chan))
1219                         return POLLHUP;
1220                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1221                         return POLLIN | POLLRDNORM;
1222                 return 0;
1223         }
1224         return mask;
1225
1226 }
1227
1228 static
1229 int lttng_channel_release(struct inode *inode, struct file *file)
1230 {
1231         struct lttng_channel *channel = file->private_data;
1232
1233         if (channel)
1234                 fput(channel->session->file);
1235         return 0;
1236 }
1237
1238 static
1239 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1240 {
1241         struct lttng_channel *channel = file->private_data;
1242
1243         if (channel) {
1244                 lttng_metadata_channel_destroy(channel);
1245                 fput(channel->session->file);
1246         }
1247
1248         return 0;
1249 }
1250
1251 static const struct file_operations lttng_channel_fops = {
1252         .owner = THIS_MODULE,
1253         .release = lttng_channel_release,
1254         .poll = lttng_channel_poll,
1255         .unlocked_ioctl = lttng_channel_ioctl,
1256 #ifdef CONFIG_COMPAT
1257         .compat_ioctl = lttng_channel_ioctl,
1258 #endif
1259 };
1260
1261 static const struct file_operations lttng_metadata_fops = {
1262         .owner = THIS_MODULE,
1263         .release = lttng_metadata_channel_release,
1264         .unlocked_ioctl = lttng_metadata_ioctl,
1265 #ifdef CONFIG_COMPAT
1266         .compat_ioctl = lttng_metadata_ioctl,
1267 #endif
1268 };
1269
1270 /**
1271  *      lttng_event_ioctl - lttng syscall through ioctl
1272  *
1273  *      @file: the file
1274  *      @cmd: the command
1275  *      @arg: command arg
1276  *
1277  *      This ioctl implements lttng commands:
1278  *      LTTNG_KERNEL_CONTEXT
1279  *              Prepend a context field to each record of this event
1280  *      LTTNG_KERNEL_ENABLE
1281  *              Enable recording for this event (weak enable)
1282  *      LTTNG_KERNEL_DISABLE
1283  *              Disable recording for this event (strong disable)
1284  */
1285 static
1286 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1287 {
1288         struct lttng_event *event = file->private_data;
1289
1290         switch (cmd) {
1291         case LTTNG_KERNEL_OLD_CONTEXT:
1292         {
1293                 struct lttng_kernel_context *ucontext_param;
1294                 struct lttng_kernel_old_context *old_ucontext_param;
1295                 int ret;
1296
1297                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1298                                 GFP_KERNEL);
1299                 if (!ucontext_param) {
1300                         ret = -ENOMEM;
1301                         goto old_ctx_end;
1302                 }
1303                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1304                                 GFP_KERNEL);
1305                 if (!old_ucontext_param) {
1306                         ret = -ENOMEM;
1307                         goto old_ctx_error_free_param;
1308                 }
1309
1310                 if (copy_from_user(old_ucontext_param,
1311                                         (struct lttng_kernel_old_context __user *) arg,
1312                                         sizeof(struct lttng_kernel_old_context))) {
1313                         ret = -EFAULT;
1314                         goto old_ctx_error_free_old_param;
1315                 }
1316                 ucontext_param->ctx = old_ucontext_param->ctx;
1317                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1318                                 sizeof(ucontext_param->padding));
1319                 /* only type that uses the union */
1320                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1321                         ucontext_param->u.perf_counter.type =
1322                                 old_ucontext_param->u.perf_counter.type;
1323                         ucontext_param->u.perf_counter.config =
1324                                 old_ucontext_param->u.perf_counter.config;
1325                         memcpy(ucontext_param->u.perf_counter.name,
1326                                         old_ucontext_param->u.perf_counter.name,
1327                                         sizeof(ucontext_param->u.perf_counter.name));
1328                 }
1329
1330                 ret = lttng_abi_add_context(file,
1331                                 ucontext_param,
1332                                 &event->ctx, event->chan->session);
1333
1334 old_ctx_error_free_old_param:
1335                 kfree(old_ucontext_param);
1336 old_ctx_error_free_param:
1337                 kfree(ucontext_param);
1338 old_ctx_end:
1339                 return ret;
1340         }
1341         case LTTNG_KERNEL_CONTEXT:
1342         {
1343                 struct lttng_kernel_context ucontext_param;
1344
1345                 if (copy_from_user(&ucontext_param,
1346                                         (struct lttng_kernel_context __user *) arg,
1347                                         sizeof(ucontext_param)))
1348                         return -EFAULT;
1349                 return lttng_abi_add_context(file,
1350                                 &ucontext_param,
1351                                 &event->ctx, event->chan->session);
1352         }
1353         case LTTNG_KERNEL_OLD_ENABLE:
1354         case LTTNG_KERNEL_ENABLE:
1355                 return lttng_event_enable(event);
1356         case LTTNG_KERNEL_OLD_DISABLE:
1357         case LTTNG_KERNEL_DISABLE:
1358                 return lttng_event_disable(event);
1359         default:
1360                 return -ENOIOCTLCMD;
1361         }
1362 }
1363
1364 static
1365 int lttng_event_release(struct inode *inode, struct file *file)
1366 {
1367         struct lttng_event *event = file->private_data;
1368
1369         if (event)
1370                 fput(event->chan->file);
1371         return 0;
1372 }
1373
1374 /* TODO: filter control ioctl */
1375 static const struct file_operations lttng_event_fops = {
1376         .owner = THIS_MODULE,
1377         .release = lttng_event_release,
1378         .unlocked_ioctl = lttng_event_ioctl,
1379 #ifdef CONFIG_COMPAT
1380         .compat_ioctl = lttng_event_ioctl,
1381 #endif
1382 };
1383
1384 static int put_u64(uint64_t val, unsigned long arg)
1385 {
1386         return put_user(val, (uint64_t __user *) arg);
1387 }
1388
1389 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1390                 unsigned int cmd, unsigned long arg)
1391 {
1392         struct lib_ring_buffer *buf = filp->private_data;
1393         struct channel *chan = buf->backend.chan;
1394         const struct lib_ring_buffer_config *config = &chan->backend.config;
1395         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1396         int ret;
1397
1398         if (atomic_read(&chan->record_disabled))
1399                 return -EIO;
1400
1401         switch (cmd) {
1402         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1403         {
1404                 uint64_t ts;
1405
1406                 ret = ops->timestamp_begin(config, buf, &ts);
1407                 if (ret < 0)
1408                         goto error;
1409                 return put_u64(ts, arg);
1410         }
1411         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1412         {
1413                 uint64_t ts;
1414
1415                 ret = ops->timestamp_end(config, buf, &ts);
1416                 if (ret < 0)
1417                         goto error;
1418                 return put_u64(ts, arg);
1419         }
1420         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1421         {
1422                 uint64_t ed;
1423
1424                 ret = ops->events_discarded(config, buf, &ed);
1425                 if (ret < 0)
1426                         goto error;
1427                 return put_u64(ed, arg);
1428         }
1429         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1430         {
1431                 uint64_t cs;
1432
1433                 ret = ops->content_size(config, buf, &cs);
1434                 if (ret < 0)
1435                         goto error;
1436                 return put_u64(cs, arg);
1437         }
1438         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1439         {
1440                 uint64_t ps;
1441
1442                 ret = ops->packet_size(config, buf, &ps);
1443                 if (ret < 0)
1444                         goto error;
1445                 return put_u64(ps, arg);
1446         }
1447         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1448         {
1449                 uint64_t si;
1450
1451                 ret = ops->stream_id(config, buf, &si);
1452                 if (ret < 0)
1453                         goto error;
1454                 return put_u64(si, arg);
1455         }
1456         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1457         {
1458                 uint64_t ts;
1459
1460                 ret = ops->current_timestamp(config, buf, &ts);
1461                 if (ret < 0)
1462                         goto error;
1463                 return put_u64(ts, arg);
1464         }
1465         default:
1466                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1467                                 cmd, arg);
1468         }
1469
1470 error:
1471         return -ENOSYS;
1472 }
1473
1474 #ifdef CONFIG_COMPAT
1475 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1476                 unsigned int cmd, unsigned long arg)
1477 {
1478         struct lib_ring_buffer *buf = filp->private_data;
1479         struct channel *chan = buf->backend.chan;
1480         const struct lib_ring_buffer_config *config = &chan->backend.config;
1481         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1482         int ret;
1483
1484         if (atomic_read(&chan->record_disabled))
1485                 return -EIO;
1486
1487         switch (cmd) {
1488         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1489         {
1490                 uint64_t ts;
1491
1492                 ret = ops->timestamp_begin(config, buf, &ts);
1493                 if (ret < 0)
1494                         goto error;
1495                 return put_u64(ts, arg);
1496         }
1497         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1498         {
1499                 uint64_t ts;
1500
1501                 ret = ops->timestamp_end(config, buf, &ts);
1502                 if (ret < 0)
1503                         goto error;
1504                 return put_u64(ts, arg);
1505         }
1506         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1507         {
1508                 uint64_t ed;
1509
1510                 ret = ops->events_discarded(config, buf, &ed);
1511                 if (ret < 0)
1512                         goto error;
1513                 return put_u64(ed, arg);
1514         }
1515         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1516         {
1517                 uint64_t cs;
1518
1519                 ret = ops->content_size(config, buf, &cs);
1520                 if (ret < 0)
1521                         goto error;
1522                 return put_u64(cs, arg);
1523         }
1524         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1525         {
1526                 uint64_t ps;
1527
1528                 ret = ops->packet_size(config, buf, &ps);
1529                 if (ret < 0)
1530                         goto error;
1531                 return put_u64(ps, arg);
1532         }
1533         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1534         {
1535                 uint64_t si;
1536
1537                 ret = ops->stream_id(config, buf, &si);
1538                 if (ret < 0)
1539                         goto error;
1540                 return put_u64(si, arg);
1541         }
1542         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1543         {
1544                 uint64_t ts;
1545
1546                 ret = ops->current_timestamp(config, buf, &ts);
1547                 if (ret < 0)
1548                         goto error;
1549                 return put_u64(ts, arg);
1550         }
1551         default:
1552                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1553                                 cmd, arg);
1554         }
1555
1556 error:
1557         return -ENOSYS;
1558 }
1559 #endif /* CONFIG_COMPAT */
1560
1561 static void lttng_stream_override_ring_buffer_fops(void)
1562 {
1563         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1564         lttng_stream_ring_buffer_file_operations.open =
1565                 lib_ring_buffer_file_operations.open;
1566         lttng_stream_ring_buffer_file_operations.release =
1567                 lib_ring_buffer_file_operations.release;
1568         lttng_stream_ring_buffer_file_operations.poll =
1569                 lib_ring_buffer_file_operations.poll;
1570         lttng_stream_ring_buffer_file_operations.splice_read =
1571                 lib_ring_buffer_file_operations.splice_read;
1572         lttng_stream_ring_buffer_file_operations.mmap =
1573                 lib_ring_buffer_file_operations.mmap;
1574         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1575                 lttng_stream_ring_buffer_ioctl;
1576         lttng_stream_ring_buffer_file_operations.llseek =
1577                 lib_ring_buffer_file_operations.llseek;
1578 #ifdef CONFIG_COMPAT
1579         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1580                 lttng_stream_ring_buffer_compat_ioctl;
1581 #endif
1582 }
1583
1584 int __init lttng_abi_init(void)
1585 {
1586         int ret = 0;
1587
1588         wrapper_vmalloc_sync_all();
1589         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1590                                         &lttng_fops, NULL);
1591
1592         if (!lttng_proc_dentry) {
1593                 printk(KERN_ERR "Error creating LTTng control file\n");
1594                 ret = -ENOMEM;
1595                 goto error;
1596         }
1597         lttng_stream_override_ring_buffer_fops();
1598
1599 error:
1600         return ret;
1601 }
1602
1603 /* No __exit annotation because used by init error path too. */
1604 void lttng_abi_exit(void)
1605 {
1606         if (lttng_proc_dentry)
1607                 remove_proc_entry("lttng", NULL);
1608 }