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 <wrapper/kref.h>
  54 #include <lttng-abi.h>
  55 #include <lttng-abi-old.h>
  56 #include <lttng-events.h>
  57 #include <lttng-tracer.h>
  58 #include <lib/ringbuffer/frontend_types.h>
  59
  60 /*
  61  * This is LTTng's own personal way to create a system call as an external
  62  * module. We use ioctl() on /proc/lttng.
  63  */
  64
  65 static struct proc_dir_entry *lttng_proc_dentry;
  66 static const struct file_operations lttng_fops;
  67 static const struct file_operations lttng_session_fops;
  68 static const struct file_operations lttng_channel_fops;
  69 static const struct file_operations lttng_metadata_fops;
  70 static const struct file_operations lttng_event_fops;
  71 static struct file_operations lttng_stream_ring_buffer_file_operations;
  72
  73 static int put_u64(uint64_t val, unsigned long arg);
  74
  75 /*
  76  * Teardown management: opened file descriptors keep a refcount on the module,
  77  * so it can only exit when all file descriptors are closed.
  78  */
  79
  80 static
  81 int lttng_abi_create_session(void)
  82 {
  83         struct lttng_session *session;
  84         struct file *session_file;
  85         int session_fd, ret;
  86
  87         session = lttng_session_create();
  88         if (!session)
  89                 return -ENOMEM;
  90         session_fd = lttng_get_unused_fd();
  91         if (session_fd < 0) {
  92                 ret = session_fd;
  93                 goto fd_error;
  94         }
  95         session_file = anon_inode_getfile("[lttng_session]",
  96                                           &lttng_session_fops,
  97                                           session, O_RDWR);
  98         if (IS_ERR(session_file)) {
  99                 ret = PTR_ERR(session_file);
 100                 goto file_error;
 101         }
 102         session->file = session_file;
 103         fd_install(session_fd, session_file);
 104         return session_fd;
 105
 106 file_error:
 107         put_unused_fd(session_fd);
 108 fd_error:
 109         lttng_session_destroy(session);
 110         return ret;
 111 }
 112
 113 static
 114 int lttng_abi_tracepoint_list(void)
 115 {
 116         struct file *tracepoint_list_file;
 117         int file_fd, ret;
 118
 119         file_fd = lttng_get_unused_fd();
 120         if (file_fd < 0) {
 121                 ret = file_fd;
 122                 goto fd_error;
 123         }
 124
 125         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 126                                           &lttng_tracepoint_list_fops,
 127                                           NULL, O_RDWR);
 128         if (IS_ERR(tracepoint_list_file)) {
 129                 ret = PTR_ERR(tracepoint_list_file);
 130                 goto file_error;
 131         }
 132         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 133         if (ret < 0)
 134                 goto open_error;
 135         fd_install(file_fd, tracepoint_list_file);
 136         return file_fd;
 137
 138 open_error:
 139         fput(tracepoint_list_file);
 140 file_error:
 141         put_unused_fd(file_fd);
 142 fd_error:
 143         return ret;
 144 }
 145
 146 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 147 static inline
 148 int lttng_abi_syscall_list(void)
 149 {
 150         return -ENOSYS;
 151 }
 152 #else
 153 static
 154 int lttng_abi_syscall_list(void)
 155 {
 156         struct file *syscall_list_file;
 157         int file_fd, ret;
 158
 159         file_fd = lttng_get_unused_fd();
 160         if (file_fd < 0) {
 161                 ret = file_fd;
 162                 goto fd_error;
 163         }
 164
 165         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 166                                           &lttng_syscall_list_fops,
 167                                           NULL, O_RDWR);
 168         if (IS_ERR(syscall_list_file)) {
 169                 ret = PTR_ERR(syscall_list_file);
 170                 goto file_error;
 171         }
 172         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 173         if (ret < 0)
 174                 goto open_error;
 175         fd_install(file_fd, syscall_list_file);
 176         return file_fd;
 177
 178 open_error:
 179         fput(syscall_list_file);
 180 file_error:
 181         put_unused_fd(file_fd);
 182 fd_error:
 183         return ret;
 184 }
 185 #endif
 186
 187 static
 188 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 189 {
 190         v->major = LTTNG_MODULES_MAJOR_VERSION;
 191         v->minor = LTTNG_MODULES_MINOR_VERSION;
 192         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 193 }
 194
 195 static
 196 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 197 {
 198         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 199         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 200 }
 201
 202 static
 203 long lttng_abi_add_context(struct file *file,
 204         struct lttng_kernel_context *context_param,
 205         struct lttng_ctx **ctx, struct lttng_session *session)
 206 {
 207
 208         if (session->been_active)
 209                 return -EPERM;
 210
 211         switch (context_param->ctx) {
 212         case LTTNG_KERNEL_CONTEXT_PID:
 213                 return lttng_add_pid_to_ctx(ctx);
 214         case LTTNG_KERNEL_CONTEXT_PRIO:
 215                 return lttng_add_prio_to_ctx(ctx);
 216         case LTTNG_KERNEL_CONTEXT_NICE:
 217                 return lttng_add_nice_to_ctx(ctx);
 218         case LTTNG_KERNEL_CONTEXT_VPID:
 219                 return lttng_add_vpid_to_ctx(ctx);
 220         case LTTNG_KERNEL_CONTEXT_TID:
 221                 return lttng_add_tid_to_ctx(ctx);
 222         case LTTNG_KERNEL_CONTEXT_VTID:
 223                 return lttng_add_vtid_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_PPID:
 225                 return lttng_add_ppid_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_VPPID:
 227                 return lttng_add_vppid_to_ctx(ctx);
 228         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 229                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 230                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 231                                 context_param->u.perf_counter.config,
 232                                 context_param->u.perf_counter.name,
 233                                 ctx);
 234         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 235                 return lttng_add_procname_to_ctx(ctx);
 236         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 237                 return lttng_add_hostname_to_ctx(ctx);
 238         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 239                 return lttng_add_cpu_id_to_ctx(ctx);
 240         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 241                 return lttng_add_interruptible_to_ctx(ctx);
 242         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 243                 return lttng_add_need_reschedule_to_ctx(ctx);
 244         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 245                 return lttng_add_preemptible_to_ctx(ctx);
 246         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 247                 return lttng_add_migratable_to_ctx(ctx);
 248         default:
 249                 return -EINVAL;
 250         }
 251 }
 252
 253 /**
 254  *      lttng_ioctl - lttng syscall through ioctl
 255  *
 256  *      @file: the file
 257  *      @cmd: the command
 258  *      @arg: command arg
 259  *
 260  *      This ioctl implements lttng commands:
 261  *      LTTNG_KERNEL_SESSION
 262  *              Returns a LTTng trace session file descriptor
 263  *      LTTNG_KERNEL_TRACER_VERSION
 264  *              Returns the LTTng kernel tracer version
 265  *      LTTNG_KERNEL_TRACEPOINT_LIST
 266  *              Returns a file descriptor listing available tracepoints
 267  *      LTTNG_KERNEL_WAIT_QUIESCENT
 268  *              Returns after all previously running probes have completed
 269  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 270  *              Returns the LTTng kernel tracer ABI version
 271  *
 272  * The returned session will be deleted when its file descriptor is closed.
 273  */
 274 static
 275 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 276 {
 277         switch (cmd) {
 278         case LTTNG_KERNEL_OLD_SESSION:
 279         case LTTNG_KERNEL_SESSION:
 280                 return lttng_abi_create_session();
 281         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 282         {
 283                 struct lttng_kernel_tracer_version v;
 284                 struct lttng_kernel_old_tracer_version oldv;
 285                 struct lttng_kernel_old_tracer_version *uversion =
 286                         (struct lttng_kernel_old_tracer_version __user *) arg;
 287
 288                 lttng_abi_tracer_version(&v);
 289                 oldv.major = v.major;
 290                 oldv.minor = v.minor;
 291                 oldv.patchlevel = v.patchlevel;
 292
 293                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 294                         return -EFAULT;
 295                 return 0;
 296         }
 297         case LTTNG_KERNEL_TRACER_VERSION:
 298         {
 299                 struct lttng_kernel_tracer_version version;
 300                 struct lttng_kernel_tracer_version *uversion =
 301                         (struct lttng_kernel_tracer_version __user *) arg;
 302
 303                 lttng_abi_tracer_version(&version);
 304
 305                 if (copy_to_user(uversion, &version, sizeof(version)))
 306                         return -EFAULT;
 307                 return 0;
 308         }
 309         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 310         {
 311                 struct lttng_kernel_tracer_abi_version version;
 312                 struct lttng_kernel_tracer_abi_version *uversion =
 313                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 314
 315                 lttng_abi_tracer_abi_version(&version);
 316
 317                 if (copy_to_user(uversion, &version, sizeof(version)))
 318                         return -EFAULT;
 319                 return 0;
 320         }
 321         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 322         case LTTNG_KERNEL_TRACEPOINT_LIST:
 323                 return lttng_abi_tracepoint_list();
 324         case LTTNG_KERNEL_SYSCALL_LIST:
 325                 return lttng_abi_syscall_list();
 326         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 327         case LTTNG_KERNEL_WAIT_QUIESCENT:
 328                 synchronize_trace();
 329                 return 0;
 330         case LTTNG_KERNEL_OLD_CALIBRATE:
 331         {
 332                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 333                         (struct lttng_kernel_old_calibrate __user *) arg;
 334                 struct lttng_kernel_old_calibrate old_calibrate;
 335                 struct lttng_kernel_calibrate calibrate;
 336                 int ret;
 337
 338                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 339                         return -EFAULT;
 340                 calibrate.type = old_calibrate.type;
 341                 ret = lttng_calibrate(&calibrate);
 342                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 343                         return -EFAULT;
 344                 return ret;
 345         }
 346         case LTTNG_KERNEL_CALIBRATE:
 347         {
 348                 struct lttng_kernel_calibrate __user *ucalibrate =
 349                         (struct lttng_kernel_calibrate __user *) arg;
 350                 struct lttng_kernel_calibrate calibrate;
 351                 int ret;
 352
 353                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 354                         return -EFAULT;
 355                 ret = lttng_calibrate(&calibrate);
 356                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 357                         return -EFAULT;
 358                 return ret;
 359         }
 360         default:
 361                 return -ENOIOCTLCMD;
 362         }
 363 }
 364
 365 static const struct file_operations lttng_fops = {
 366         .owner = THIS_MODULE,
 367         .unlocked_ioctl = lttng_ioctl,
 368 #ifdef CONFIG_COMPAT
 369         .compat_ioctl = lttng_ioctl,
 370 #endif
 371 };
 372
 373 static
 374 int lttng_abi_create_channel(struct file *session_file,
 375                              struct lttng_kernel_channel *chan_param,
 376                              enum channel_type channel_type)
 377 {
 378         struct lttng_session *session = session_file->private_data;
 379         const struct file_operations *fops = NULL;
 380         const char *transport_name;
 381         struct lttng_channel *chan;
 382         struct file *chan_file;
 383         int chan_fd;
 384         int ret = 0;
 385
 386         chan_fd = lttng_get_unused_fd();
 387         if (chan_fd < 0) {
 388                 ret = chan_fd;
 389                 goto fd_error;
 390         }
 391         switch (channel_type) {
 392         case PER_CPU_CHANNEL:
 393                 fops = &lttng_channel_fops;
 394                 break;
 395         case METADATA_CHANNEL:
 396                 fops = &lttng_metadata_fops;
 397                 break;
 398         }
 399
 400         chan_file = anon_inode_getfile("[lttng_channel]",
 401                                        fops,
 402                                        NULL, O_RDWR);
 403         if (IS_ERR(chan_file)) {
 404                 ret = PTR_ERR(chan_file);
 405                 goto file_error;
 406         }
 407         switch (channel_type) {
 408         case PER_CPU_CHANNEL:
 409                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 410                         transport_name = chan_param->overwrite ?
 411                                 "relay-overwrite" : "relay-discard";
 412                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 413                         transport_name = chan_param->overwrite ?
 414                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 415                 } else {
 416                         return -EINVAL;
 417                 }
 418                 break;
 419         case METADATA_CHANNEL:
 420                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 421                         transport_name = "relay-metadata";
 422                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 423                         transport_name = "relay-metadata-mmap";
 424                 else
 425                         return -EINVAL;
 426                 break;
 427         default:
 428                 transport_name = "<unknown>";
 429                 break;
 430         }
 431         if (atomic_long_add_unless(&session_file->f_count,
 432                 1, INT_MAX) == INT_MAX) {
 433                 goto refcount_error;
 434         }
 435         /*
 436          * We tolerate no failure path after channel creation. It will stay
 437          * invariant for the rest of the session.
 438          */
 439         chan = lttng_channel_create(session, transport_name, NULL,
 440                                   chan_param->subbuf_size,
 441                                   chan_param->num_subbuf,
 442                                   chan_param->switch_timer_interval,
 443                                   chan_param->read_timer_interval,
 444                                   channel_type);
 445         if (!chan) {
 446                 ret = -EINVAL;
 447                 goto chan_error;
 448         }
 449         chan->file = chan_file;
 450         chan_file->private_data = chan;
 451         fd_install(chan_fd, chan_file);
 452
 453         return chan_fd;
 454
 455 chan_error:
 456         atomic_long_dec(&session_file->f_count);
 457 refcount_error:
 458         fput(chan_file);
 459 file_error:
 460         put_unused_fd(chan_fd);
 461 fd_error:
 462         return ret;
 463 }
 464
 465 /**
 466  *      lttng_session_ioctl - lttng session fd ioctl
 467  *
 468  *      @file: the file
 469  *      @cmd: the command
 470  *      @arg: command arg
 471  *
 472  *      This ioctl implements lttng commands:
 473  *      LTTNG_KERNEL_CHANNEL
 474  *              Returns a LTTng channel file descriptor
 475  *      LTTNG_KERNEL_ENABLE
 476  *              Enables tracing for a session (weak enable)
 477  *      LTTNG_KERNEL_DISABLE
 478  *              Disables tracing for a session (strong disable)
 479  *      LTTNG_KERNEL_METADATA
 480  *              Returns a LTTng metadata file descriptor
 481  *      LTTNG_KERNEL_SESSION_TRACK_PID
 482  *              Add PID to session tracker
 483  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 484  *              Remove PID from session tracker
 485  *
 486  * The returned channel will be deleted when its file descriptor is closed.
 487  */
 488 static
 489 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 490 {
 491         struct lttng_session *session = file->private_data;
 492
 493         switch (cmd) {
 494         case LTTNG_KERNEL_OLD_CHANNEL:
 495         {
 496                 struct lttng_kernel_channel chan_param;
 497                 struct lttng_kernel_old_channel old_chan_param;
 498
 499                 if (copy_from_user(&old_chan_param,
 500                                 (struct lttng_kernel_old_channel __user *) arg,
 501                                 sizeof(struct lttng_kernel_old_channel)))
 502                         return -EFAULT;
 503                 chan_param.overwrite = old_chan_param.overwrite;
 504                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 505                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 506                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 507                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 508                 chan_param.output = old_chan_param.output;
 509
 510                 return lttng_abi_create_channel(file, &chan_param,
 511                                 PER_CPU_CHANNEL);
 512         }
 513         case LTTNG_KERNEL_CHANNEL:
 514         {
 515                 struct lttng_kernel_channel chan_param;
 516
 517                 if (copy_from_user(&chan_param,
 518                                 (struct lttng_kernel_channel __user *) arg,
 519                                 sizeof(struct lttng_kernel_channel)))
 520                         return -EFAULT;
 521                 return lttng_abi_create_channel(file, &chan_param,
 522                                 PER_CPU_CHANNEL);
 523         }
 524         case LTTNG_KERNEL_OLD_SESSION_START:
 525         case LTTNG_KERNEL_OLD_ENABLE:
 526         case LTTNG_KERNEL_SESSION_START:
 527         case LTTNG_KERNEL_ENABLE:
 528                 return lttng_session_enable(session);
 529         case LTTNG_KERNEL_OLD_SESSION_STOP:
 530         case LTTNG_KERNEL_OLD_DISABLE:
 531         case LTTNG_KERNEL_SESSION_STOP:
 532         case LTTNG_KERNEL_DISABLE:
 533                 return lttng_session_disable(session);
 534         case LTTNG_KERNEL_OLD_METADATA:
 535         {
 536                 struct lttng_kernel_channel chan_param;
 537                 struct lttng_kernel_old_channel old_chan_param;
 538
 539                 if (copy_from_user(&old_chan_param,
 540                                 (struct lttng_kernel_old_channel __user *) arg,
 541                                 sizeof(struct lttng_kernel_old_channel)))
 542                         return -EFAULT;
 543                 chan_param.overwrite = old_chan_param.overwrite;
 544                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 545                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 546                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 547                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 548                 chan_param.output = old_chan_param.output;
 549
 550                 return lttng_abi_create_channel(file, &chan_param,
 551                                 METADATA_CHANNEL);
 552         }
 553         case LTTNG_KERNEL_METADATA:
 554         {
 555                 struct lttng_kernel_channel chan_param;
 556
 557                 if (copy_from_user(&chan_param,
 558                                         (struct lttng_kernel_channel __user *) arg,
 559                                         sizeof(struct lttng_kernel_channel)))
 560                         return -EFAULT;
 561                 return lttng_abi_create_channel(file, &chan_param,
 562                                 METADATA_CHANNEL);
 563         }
 564         case LTTNG_KERNEL_SESSION_TRACK_PID:
 565                 return lttng_session_track_pid(session, (int) arg);
 566         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 567                 return lttng_session_untrack_pid(session, (int) arg);
 568         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 569                 return lttng_session_list_tracker_pids(session);
 570         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 571                 return lttng_session_metadata_regenerate(session);
 572         case LTTNG_KERNEL_SESSION_STATEDUMP:
 573                 return lttng_session_statedump(session);
 574         default:
 575                 return -ENOIOCTLCMD;
 576         }
 577 }
 578
 579 /*
 580  * Called when the last file reference is dropped.
 581  *
 582  * Big fat note: channels and events are invariant for the whole session after
 583  * their creation. So this session destruction also destroys all channel and
 584  * event structures specific to this session (they are not destroyed when their
 585  * individual file is released).
 586  */
 587 static
 588 int lttng_session_release(struct inode *inode, struct file *file)
 589 {
 590         struct lttng_session *session = file->private_data;
 591
 592         if (session)
 593                 lttng_session_destroy(session);
 594         return 0;
 595 }
 596
 597 static const struct file_operations lttng_session_fops = {
 598         .owner = THIS_MODULE,
 599         .release = lttng_session_release,
 600         .unlocked_ioctl = lttng_session_ioctl,
 601 #ifdef CONFIG_COMPAT
 602         .compat_ioctl = lttng_session_ioctl,
 603 #endif
 604 };
 605
 606 /**
 607  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 608  *      @filp: the file
 609  *      @wait: poll table
 610  *
 611  *      Handles the poll operations for the metadata channels.
 612  */
 613 static
 614 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 615                 poll_table *wait)
 616 {
 617         struct lttng_metadata_stream *stream = filp->private_data;
 618         struct lib_ring_buffer *buf = stream->priv;
 619         int finalized;
 620         unsigned int mask = 0;
 621
 622         if (filp->f_mode & FMODE_READ) {
 623                 poll_wait_set_exclusive(wait);
 624                 poll_wait(filp, &stream->read_wait, wait);
 625
 626                 finalized = stream->finalized;
 627
 628                 /*
 629                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 630                  * ordering finalized load before offsets loads.
 631                  */
 632                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 633
 634                 if (finalized)
 635                         mask |= POLLHUP;
 636
 637                 mutex_lock(&stream->metadata_cache->lock);
 638                 if (stream->metadata_cache->metadata_written >
 639                                 stream->metadata_out)
 640                         mask |= POLLIN;
 641                 mutex_unlock(&stream->metadata_cache->lock);
 642         }
 643
 644         return mask;
 645 }
 646
 647 static
 648 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 649                 unsigned int cmd, unsigned long arg)
 650 {
 651         struct lttng_metadata_stream *stream = filp->private_data;
 652
 653         stream->metadata_out = stream->metadata_in;
 654 }
 655
 656 static
 657 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 658                 unsigned int cmd, unsigned long arg)
 659 {
 660         int ret;
 661         struct lttng_metadata_stream *stream = filp->private_data;
 662         struct lib_ring_buffer *buf = stream->priv;
 663
 664         switch (cmd) {
 665         case RING_BUFFER_GET_NEXT_SUBBUF:
 666         {
 667                 struct lttng_metadata_stream *stream = filp->private_data;
 668                 struct lib_ring_buffer *buf = stream->priv;
 669                 struct channel *chan = buf->backend.chan;
 670
 671                 ret = lttng_metadata_output_channel(stream, chan);
 672                 if (ret > 0) {
 673                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 674                         ret = 0;
 675                 } else if (ret < 0)
 676                         goto err;
 677                 break;
 678         }
 679         case RING_BUFFER_GET_SUBBUF:
 680         {
 681                 /*
 682                  * Random access is not allowed for metadata channel.
 683                  */
 684                 return -ENOSYS;
 685         }
 686         case RING_BUFFER_FLUSH:
 687         {
 688                 struct lttng_metadata_stream *stream = filp->private_data;
 689                 struct lib_ring_buffer *buf = stream->priv;
 690                 struct channel *chan = buf->backend.chan;
 691
 692                 /*
 693                  * Before doing the actual ring buffer flush, write up to one
 694                  * packet of metadata in the ring buffer.
 695                  */
 696                 ret = lttng_metadata_output_channel(stream, chan);
 697                 if (ret < 0)
 698                         goto err;
 699                 break;
 700         }
 701         case RING_BUFFER_GET_METADATA_VERSION:
 702         {
 703                 struct lttng_metadata_stream *stream = filp->private_data;
 704
 705                 return put_u64(stream->version, arg);
 706         }
 707         case RING_BUFFER_SNAPSHOT:
 708         {
 709                 /*
 710                  * Force the buffer to quiescent so the ring buffer
 711                  * don't attempt to perform a SWITCH_FLUSH, which would
 712                  * desynchronize the client accounting of the amount of
 713                  * data available in the buffer from the ring buffer
 714                  * view.
 715                  */
 716                 buf->quiescent = true;
 717                 break;
 718         }
 719         default:
 720                 break;
 721         }
 722         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 723
 724         /* Performing lib ring buffer ioctl after our own. */
 725         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 726         if (ret < 0)
 727                 goto err;
 728
 729         switch (cmd) {
 730         case RING_BUFFER_PUT_NEXT_SUBBUF:
 731         {
 732                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 733                                 cmd, arg);
 734                 break;
 735         }
 736         default:
 737                 break;
 738         }
 739 err:
 740         return ret;
 741 }
 742
 743 #ifdef CONFIG_COMPAT
 744 static
 745 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 746                 unsigned int cmd, unsigned long arg)
 747 {
 748         int ret;
 749         struct lttng_metadata_stream *stream = filp->private_data;
 750         struct lib_ring_buffer *buf = stream->priv;
 751
 752         switch (cmd) {
 753         case RING_BUFFER_GET_NEXT_SUBBUF:
 754         {
 755                 struct lttng_metadata_stream *stream = filp->private_data;
 756                 struct lib_ring_buffer *buf = stream->priv;
 757                 struct channel *chan = buf->backend.chan;
 758
 759                 ret = lttng_metadata_output_channel(stream, chan);
 760                 if (ret > 0) {
 761                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 762                         ret = 0;
 763                 } else if (ret < 0)
 764                         goto err;
 765                 break;
 766         }
 767         case RING_BUFFER_GET_SUBBUF:
 768         {
 769                 /*
 770                  * Random access is not allowed for metadata channel.
 771                  */
 772                 return -ENOSYS;
 773         }
 774         case RING_BUFFER_FLUSH:
 775         {
 776                 struct lttng_metadata_stream *stream = filp->private_data;
 777                 struct lib_ring_buffer *buf = stream->priv;
 778                 struct channel *chan = buf->backend.chan;
 779
 780                 /*
 781                  * Before doing the actual ring buffer flush, write up to one
 782                  * packet of metadata in the ring buffer.
 783                  */
 784                 ret = lttng_metadata_output_channel(stream, chan);
 785                 if (ret < 0)
 786                         goto err;
 787                 break;
 788         }
 789         case RING_BUFFER_GET_METADATA_VERSION:
 790         {
 791                 struct lttng_metadata_stream *stream = filp->private_data;
 792
 793                 return put_u64(stream->version, arg);
 794         }
 795         case RING_BUFFER_SNAPSHOT:
 796         {
 797                 /*
 798                  * Force the buffer to quiescent so the ring buffer
 799                  * don't attempt to perform a SWITCH_FLUSH, which would
 800                  * desynchronize the client accounting of the amount of
 801                  * data available in the buffer from the ring buffer
 802                  * view.
 803                  */
 804                 buf->quiescent = true;
 805                 break;
 806         }
 807         default:
 808                 break;
 809         }
 810         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 811
 812         /* Performing lib ring buffer ioctl after our own. */
 813         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 814         if (ret < 0)
 815                 goto err;
 816
 817         switch (cmd) {
 818         case RING_BUFFER_PUT_NEXT_SUBBUF:
 819         {
 820                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 821                                 cmd, arg);
 822                 break;
 823         }
 824         default:
 825                 break;
 826         }
 827 err:
 828         return ret;
 829 }
 830 #endif
 831
 832 /*
 833  * This is not used by anonymous file descriptors. This code is left
 834  * there if we ever want to implement an inode with open() operation.
 835  */
 836 static
 837 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 838 {
 839         struct lttng_metadata_stream *stream = inode->i_private;
 840         struct lib_ring_buffer *buf = stream->priv;
 841
 842         file->private_data = buf;
 843         /*
 844          * Since life-time of metadata cache differs from that of
 845          * session, we need to keep our own reference on the transport.
 846          */
 847         if (!try_module_get(stream->transport->owner)) {
 848                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 849                 return -EBUSY;
 850         }
 851         return lib_ring_buffer_open(inode, file, buf);
 852 }
 853
 854 static
 855 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 856 {
 857         struct lttng_metadata_stream *stream = file->private_data;
 858         struct lib_ring_buffer *buf = stream->priv;
 859
 860         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 861         module_put(stream->transport->owner);
 862         return lib_ring_buffer_release(inode, file, buf);
 863 }
 864
 865 static
 866 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 867                 struct pipe_inode_info *pipe, size_t len,
 868                 unsigned int flags)
 869 {
 870         struct lttng_metadata_stream *stream = in->private_data;
 871         struct lib_ring_buffer *buf = stream->priv;
 872
 873         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 874                         flags, buf);
 875 }
 876
 877 static
 878 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 879                 struct vm_area_struct *vma)
 880 {
 881         struct lttng_metadata_stream *stream = filp->private_data;
 882         struct lib_ring_buffer *buf = stream->priv;
 883
 884         return lib_ring_buffer_mmap(filp, vma, buf);
 885 }
 886
 887 static
 888 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 889         .owner = THIS_MODULE,
 890         .open = lttng_metadata_ring_buffer_open,
 891         .release = lttng_metadata_ring_buffer_release,
 892         .poll = lttng_metadata_ring_buffer_poll,
 893         .splice_read = lttng_metadata_ring_buffer_splice_read,
 894         .mmap = lttng_metadata_ring_buffer_mmap,
 895         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 896         .llseek = vfs_lib_ring_buffer_no_llseek,
 897 #ifdef CONFIG_COMPAT
 898         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 899 #endif
 900 };
 901
 902 static
 903 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 904                 const struct file_operations *fops)
 905 {
 906         int stream_fd, ret;
 907         struct file *stream_file;
 908
 909         stream_fd = lttng_get_unused_fd();
 910         if (stream_fd < 0) {
 911                 ret = stream_fd;
 912                 goto fd_error;
 913         }
 914         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 915                         stream_priv, O_RDWR);
 916         if (IS_ERR(stream_file)) {
 917                 ret = PTR_ERR(stream_file);
 918                 goto file_error;
 919         }
 920         /*
 921          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 922          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 923          * file descriptor, so we set FMODE_PREAD here.
 924          */
 925         stream_file->f_mode |= FMODE_PREAD;
 926         fd_install(stream_fd, stream_file);
 927         /*
 928          * The stream holds a reference to the channel within the generic ring
 929          * buffer library, so no need to hold a refcount on the channel and
 930          * session files here.
 931          */
 932         return stream_fd;
 933
 934 file_error:
 935         put_unused_fd(stream_fd);
 936 fd_error:
 937         return ret;
 938 }
 939
 940 static
 941 int lttng_abi_open_stream(struct file *channel_file)
 942 {
 943         struct lttng_channel *channel = channel_file->private_data;
 944         struct lib_ring_buffer *buf;
 945         int ret;
 946         void *stream_priv;
 947
 948         buf = channel->ops->buffer_read_open(channel->chan);
 949         if (!buf)
 950                 return -ENOENT;
 951
 952         stream_priv = buf;
 953         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 954                         &lttng_stream_ring_buffer_file_operations);
 955         if (ret < 0)
 956                 goto fd_error;
 957
 958         return ret;
 959
 960 fd_error:
 961         channel->ops->buffer_read_close(buf);
 962         return ret;
 963 }
 964
 965 static
 966 int lttng_abi_open_metadata_stream(struct file *channel_file)
 967 {
 968         struct lttng_channel *channel = channel_file->private_data;
 969         struct lttng_session *session = channel->session;
 970         struct lib_ring_buffer *buf;
 971         int ret;
 972         struct lttng_metadata_stream *metadata_stream;
 973         void *stream_priv;
 974
 975         buf = channel->ops->buffer_read_open(channel->chan);
 976         if (!buf)
 977                 return -ENOENT;
 978
 979         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 980                         GFP_KERNEL);
 981         if (!metadata_stream) {
 982                 ret = -ENOMEM;
 983                 goto nomem;
 984         }
 985         metadata_stream->metadata_cache = session->metadata_cache;
 986         init_waitqueue_head(&metadata_stream->read_wait);
 987         metadata_stream->priv = buf;
 988         stream_priv = metadata_stream;
 989         metadata_stream->transport = channel->transport;
 990
 991         /*
 992          * Since life-time of metadata cache differs from that of
 993          * session, we need to keep our own reference on the transport.
 994          */
 995         if (!try_module_get(metadata_stream->transport->owner)) {
 996                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 997                 ret = -EINVAL;
 998                 goto notransport;
 999         }
1000
1001         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1002                 ret = -EOVERFLOW;
1003                 goto kref_error;
1004         }
1005
1006         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1007                         &lttng_metadata_ring_buffer_file_operations);
1008         if (ret < 0)
1009                 goto fd_error;
1010
1011         list_add(&metadata_stream->list,
1012                 &session->metadata_cache->metadata_stream);
1013         return ret;
1014
1015 fd_error:
1016         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1017 kref_error:
1018         module_put(metadata_stream->transport->owner);
1019 notransport:
1020         kfree(metadata_stream);
1021 nomem:
1022         channel->ops->buffer_read_close(buf);
1023         return ret;
1024 }
1025
1026 static
1027 int lttng_abi_create_event(struct file *channel_file,
1028                            struct lttng_kernel_event *event_param)
1029 {
1030         struct lttng_channel *channel = channel_file->private_data;
1031         int event_fd, ret;
1032         struct file *event_file;
1033         void *priv;
1034
1035         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1036         switch (event_param->instrumentation) {
1037         case LTTNG_KERNEL_KRETPROBE:
1038                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1039                 break;
1040         case LTTNG_KERNEL_KPROBE:
1041                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1042                 break;
1043         case LTTNG_KERNEL_FUNCTION:
1044                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1045                 break;
1046         default:
1047                 break;
1048         }
1049         event_fd = lttng_get_unused_fd();
1050         if (event_fd < 0) {
1051                 ret = event_fd;
1052                 goto fd_error;
1053         }
1054         event_file = anon_inode_getfile("[lttng_event]",
1055                                         &lttng_event_fops,
1056                                         NULL, O_RDWR);
1057         if (IS_ERR(event_file)) {
1058                 ret = PTR_ERR(event_file);
1059                 goto file_error;
1060         }
1061         /* The event holds a reference on the channel */
1062         if (atomic_long_add_unless(&channel_file->f_count,
1063                 1, INT_MAX) == INT_MAX) {
1064                 ret = -EOVERFLOW;
1065                 goto refcount_error;
1066         }
1067         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1068                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1069                 struct lttng_enabler *enabler;
1070
1071                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1072                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1073                                 event_param, channel);
1074                 } else {
1075                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1076                                 event_param, channel);
1077                 }
1078                 priv = enabler;
1079         } else {
1080                 struct lttng_event *event;
1081
1082                 /*
1083                  * We tolerate no failure path after event creation. It
1084                  * will stay invariant for the rest of the session.
1085                  */
1086                 event = lttng_event_create(channel, event_param,
1087                                 NULL, NULL,
1088                                 event_param->instrumentation);
1089                 WARN_ON_ONCE(!event);
1090                 if (IS_ERR(event)) {
1091                         ret = PTR_ERR(event);
1092                         goto event_error;
1093                 }
1094                 priv = event;
1095         }
1096         event_file->private_data = priv;
1097         fd_install(event_fd, event_file);
1098         return event_fd;
1099
1100 event_error:
1101         atomic_long_dec(&channel_file->f_count);
1102 refcount_error:
1103         fput(event_file);
1104 file_error:
1105         put_unused_fd(event_fd);
1106 fd_error:
1107         return ret;
1108 }
1109
1110 /**
1111  *      lttng_channel_ioctl - lttng syscall through ioctl
1112  *
1113  *      @file: the file
1114  *      @cmd: the command
1115  *      @arg: command arg
1116  *
1117  *      This ioctl implements lttng commands:
1118  *      LTTNG_KERNEL_STREAM
1119  *              Returns an event stream file descriptor or failure.
1120  *              (typically, one event stream records events from one CPU)
1121  *      LTTNG_KERNEL_EVENT
1122  *              Returns an event file descriptor or failure.
1123  *      LTTNG_KERNEL_CONTEXT
1124  *              Prepend a context field to each event in the channel
1125  *      LTTNG_KERNEL_ENABLE
1126  *              Enable recording for events in this channel (weak enable)
1127  *      LTTNG_KERNEL_DISABLE
1128  *              Disable recording for events in this channel (strong disable)
1129  *
1130  * Channel and event file descriptors also hold a reference on the session.
1131  */
1132 static
1133 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1134 {
1135         struct lttng_channel *channel = file->private_data;
1136
1137         switch (cmd) {
1138         case LTTNG_KERNEL_OLD_STREAM:
1139         case LTTNG_KERNEL_STREAM:
1140                 return lttng_abi_open_stream(file);
1141         case LTTNG_KERNEL_OLD_EVENT:
1142         {
1143                 struct lttng_kernel_event *uevent_param;
1144                 struct lttng_kernel_old_event *old_uevent_param;
1145                 int ret;
1146
1147                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1148                                 GFP_KERNEL);
1149                 if (!uevent_param) {
1150                         ret = -ENOMEM;
1151                         goto old_event_end;
1152                 }
1153                 old_uevent_param = kmalloc(
1154                                 sizeof(struct lttng_kernel_old_event),
1155                                 GFP_KERNEL);
1156                 if (!old_uevent_param) {
1157                         ret = -ENOMEM;
1158                         goto old_event_error_free_param;
1159                 }
1160                 if (copy_from_user(old_uevent_param,
1161                                 (struct lttng_kernel_old_event __user *) arg,
1162                                 sizeof(struct lttng_kernel_old_event))) {
1163                         ret = -EFAULT;
1164                         goto old_event_error_free_old_param;
1165                 }
1166
1167                 memcpy(uevent_param->name, old_uevent_param->name,
1168                                 sizeof(uevent_param->name));
1169                 uevent_param->instrumentation =
1170                         old_uevent_param->instrumentation;
1171
1172                 switch (old_uevent_param->instrumentation) {
1173                 case LTTNG_KERNEL_KPROBE:
1174                         uevent_param->u.kprobe.addr =
1175                                 old_uevent_param->u.kprobe.addr;
1176                         uevent_param->u.kprobe.offset =
1177                                 old_uevent_param->u.kprobe.offset;
1178                         memcpy(uevent_param->u.kprobe.symbol_name,
1179                                 old_uevent_param->u.kprobe.symbol_name,
1180                                 sizeof(uevent_param->u.kprobe.symbol_name));
1181                         break;
1182                 case LTTNG_KERNEL_KRETPROBE:
1183                         uevent_param->u.kretprobe.addr =
1184                                 old_uevent_param->u.kretprobe.addr;
1185                         uevent_param->u.kretprobe.offset =
1186                                 old_uevent_param->u.kretprobe.offset;
1187                         memcpy(uevent_param->u.kretprobe.symbol_name,
1188                                 old_uevent_param->u.kretprobe.symbol_name,
1189                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1190                         break;
1191                 case LTTNG_KERNEL_FUNCTION:
1192                         memcpy(uevent_param->u.ftrace.symbol_name,
1193                                         old_uevent_param->u.ftrace.symbol_name,
1194                                         sizeof(uevent_param->u.ftrace.symbol_name));
1195                         break;
1196                 default:
1197                         break;
1198                 }
1199                 ret = lttng_abi_create_event(file, uevent_param);
1200
1201 old_event_error_free_old_param:
1202                 kfree(old_uevent_param);
1203 old_event_error_free_param:
1204                 kfree(uevent_param);
1205 old_event_end:
1206                 return ret;
1207         }
1208         case LTTNG_KERNEL_EVENT:
1209         {
1210                 struct lttng_kernel_event uevent_param;
1211
1212                 if (copy_from_user(&uevent_param,
1213                                 (struct lttng_kernel_event __user *) arg,
1214                                 sizeof(uevent_param)))
1215                         return -EFAULT;
1216                 return lttng_abi_create_event(file, &uevent_param);
1217         }
1218         case LTTNG_KERNEL_OLD_CONTEXT:
1219         {
1220                 struct lttng_kernel_context *ucontext_param;
1221                 struct lttng_kernel_old_context *old_ucontext_param;
1222                 int ret;
1223
1224                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1225                                 GFP_KERNEL);
1226                 if (!ucontext_param) {
1227                         ret = -ENOMEM;
1228                         goto old_ctx_end;
1229                 }
1230                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1231                                 GFP_KERNEL);
1232                 if (!old_ucontext_param) {
1233                         ret = -ENOMEM;
1234                         goto old_ctx_error_free_param;
1235                 }
1236
1237                 if (copy_from_user(old_ucontext_param,
1238                                 (struct lttng_kernel_old_context __user *) arg,
1239                                 sizeof(struct lttng_kernel_old_context))) {
1240                         ret = -EFAULT;
1241                         goto old_ctx_error_free_old_param;
1242                 }
1243                 ucontext_param->ctx = old_ucontext_param->ctx;
1244                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1245                                 sizeof(ucontext_param->padding));
1246                 /* only type that uses the union */
1247                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1248                         ucontext_param->u.perf_counter.type =
1249                                 old_ucontext_param->u.perf_counter.type;
1250                         ucontext_param->u.perf_counter.config =
1251                                 old_ucontext_param->u.perf_counter.config;
1252                         memcpy(ucontext_param->u.perf_counter.name,
1253                                 old_ucontext_param->u.perf_counter.name,
1254                                 sizeof(ucontext_param->u.perf_counter.name));
1255                 }
1256
1257                 ret = lttng_abi_add_context(file,
1258                                 ucontext_param,
1259                                 &channel->ctx, channel->session);
1260
1261 old_ctx_error_free_old_param:
1262                 kfree(old_ucontext_param);
1263 old_ctx_error_free_param:
1264                 kfree(ucontext_param);
1265 old_ctx_end:
1266                 return ret;
1267         }
1268         case LTTNG_KERNEL_CONTEXT:
1269         {
1270                 struct lttng_kernel_context ucontext_param;
1271
1272                 if (copy_from_user(&ucontext_param,
1273                                 (struct lttng_kernel_context __user *) arg,
1274                                 sizeof(ucontext_param)))
1275                         return -EFAULT;
1276                 return lttng_abi_add_context(file,
1277                                 &ucontext_param,
1278                                 &channel->ctx, channel->session);
1279         }
1280         case LTTNG_KERNEL_OLD_ENABLE:
1281         case LTTNG_KERNEL_ENABLE:
1282                 return lttng_channel_enable(channel);
1283         case LTTNG_KERNEL_OLD_DISABLE:
1284         case LTTNG_KERNEL_DISABLE:
1285                 return lttng_channel_disable(channel);
1286         case LTTNG_KERNEL_SYSCALL_MASK:
1287                 return lttng_channel_syscall_mask(channel,
1288                         (struct lttng_kernel_syscall_mask __user *) arg);
1289         default:
1290                 return -ENOIOCTLCMD;
1291         }
1292
1293 }
1294
1295 /**
1296  *      lttng_metadata_ioctl - lttng syscall through ioctl
1297  *
1298  *      @file: the file
1299  *      @cmd: the command
1300  *      @arg: command arg
1301  *
1302  *      This ioctl implements lttng commands:
1303  *      LTTNG_KERNEL_STREAM
1304  *              Returns an event stream file descriptor or failure.
1305  *
1306  * Channel and event file descriptors also hold a reference on the session.
1307  */
1308 static
1309 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1310 {
1311         switch (cmd) {
1312         case LTTNG_KERNEL_OLD_STREAM:
1313         case LTTNG_KERNEL_STREAM:
1314                 return lttng_abi_open_metadata_stream(file);
1315         default:
1316                 return -ENOIOCTLCMD;
1317         }
1318 }
1319
1320 /**
1321  *      lttng_channel_poll - lttng stream addition/removal monitoring
1322  *
1323  *      @file: the file
1324  *      @wait: poll table
1325  */
1326 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1327 {
1328         struct lttng_channel *channel = file->private_data;
1329         unsigned int mask = 0;
1330
1331         if (file->f_mode & FMODE_READ) {
1332                 poll_wait_set_exclusive(wait);
1333                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1334                           wait);
1335
1336                 if (channel->ops->is_disabled(channel->chan))
1337                         return POLLERR;
1338                 if (channel->ops->is_finalized(channel->chan))
1339                         return POLLHUP;
1340                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1341                         return POLLIN | POLLRDNORM;
1342                 return 0;
1343         }
1344         return mask;
1345
1346 }
1347
1348 static
1349 int lttng_channel_release(struct inode *inode, struct file *file)
1350 {
1351         struct lttng_channel *channel = file->private_data;
1352
1353         if (channel)
1354                 fput(channel->session->file);
1355         return 0;
1356 }
1357
1358 static
1359 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1360 {
1361         struct lttng_channel *channel = file->private_data;
1362
1363         if (channel) {
1364                 fput(channel->session->file);
1365                 lttng_metadata_channel_destroy(channel);
1366         }
1367
1368         return 0;
1369 }
1370
1371 static const struct file_operations lttng_channel_fops = {
1372         .owner = THIS_MODULE,
1373         .release = lttng_channel_release,
1374         .poll = lttng_channel_poll,
1375         .unlocked_ioctl = lttng_channel_ioctl,
1376 #ifdef CONFIG_COMPAT
1377         .compat_ioctl = lttng_channel_ioctl,
1378 #endif
1379 };
1380
1381 static const struct file_operations lttng_metadata_fops = {
1382         .owner = THIS_MODULE,
1383         .release = lttng_metadata_channel_release,
1384         .unlocked_ioctl = lttng_metadata_ioctl,
1385 #ifdef CONFIG_COMPAT
1386         .compat_ioctl = lttng_metadata_ioctl,
1387 #endif
1388 };
1389
1390 /**
1391  *      lttng_event_ioctl - lttng syscall through ioctl
1392  *
1393  *      @file: the file
1394  *      @cmd: the command
1395  *      @arg: command arg
1396  *
1397  *      This ioctl implements lttng commands:
1398  *      LTTNG_KERNEL_CONTEXT
1399  *              Prepend a context field to each record of this event
1400  *      LTTNG_KERNEL_ENABLE
1401  *              Enable recording for this event (weak enable)
1402  *      LTTNG_KERNEL_DISABLE
1403  *              Disable recording for this event (strong disable)
1404  */
1405 static
1406 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1407 {
1408         struct lttng_event *event;
1409         struct lttng_enabler *enabler;
1410         enum lttng_event_type *evtype = file->private_data;
1411
1412         switch (cmd) {
1413         case LTTNG_KERNEL_OLD_CONTEXT:
1414         {
1415                 /* Not implemented */
1416                 return -ENOSYS;
1417         }
1418         case LTTNG_KERNEL_CONTEXT:
1419         {
1420                 /* Not implemented */
1421                 return -ENOSYS;
1422         }
1423         case LTTNG_KERNEL_OLD_ENABLE:
1424         case LTTNG_KERNEL_ENABLE:
1425                 switch (*evtype) {
1426                 case LTTNG_TYPE_EVENT:
1427                         event = file->private_data;
1428                         return lttng_event_enable(event);
1429                 case LTTNG_TYPE_ENABLER:
1430                         enabler = file->private_data;
1431                         return lttng_enabler_enable(enabler);
1432                 default:
1433                         WARN_ON_ONCE(1);
1434                         return -ENOSYS;
1435                 }
1436         case LTTNG_KERNEL_OLD_DISABLE:
1437         case LTTNG_KERNEL_DISABLE:
1438                 switch (*evtype) {
1439                 case LTTNG_TYPE_EVENT:
1440                         event = file->private_data;
1441                         return lttng_event_disable(event);
1442                 case LTTNG_TYPE_ENABLER:
1443                         enabler = file->private_data;
1444                         return lttng_enabler_disable(enabler);
1445                 default:
1446                         WARN_ON_ONCE(1);
1447                         return -ENOSYS;
1448                 }
1449         case LTTNG_KERNEL_FILTER:
1450                 switch (*evtype) {
1451                 case LTTNG_TYPE_EVENT:
1452                         return -EINVAL;
1453                 case LTTNG_TYPE_ENABLER:
1454                 {
1455                         enabler = file->private_data;
1456                         return lttng_enabler_attach_bytecode(enabler,
1457                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1458                 }
1459
1460                 }
1461         default:
1462                 return -ENOIOCTLCMD;
1463         }
1464 }
1465
1466 static
1467 int lttng_event_release(struct inode *inode, struct file *file)
1468 {
1469         struct lttng_event *event;
1470         struct lttng_enabler *enabler;
1471         enum lttng_event_type *evtype = file->private_data;
1472
1473         if (!evtype)
1474                 return 0;
1475
1476         switch (*evtype) {
1477         case LTTNG_TYPE_EVENT:
1478                 event = file->private_data;
1479                 if (event)
1480                         fput(event->chan->file);
1481                 break;
1482         case LTTNG_TYPE_ENABLER:
1483                 enabler = file->private_data;
1484                 if (enabler)
1485                         fput(enabler->chan->file);
1486                 break;
1487         default:
1488                 WARN_ON_ONCE(1);
1489                 break;
1490         }
1491
1492         return 0;
1493 }
1494
1495 /* TODO: filter control ioctl */
1496 static const struct file_operations lttng_event_fops = {
1497         .owner = THIS_MODULE,
1498         .release = lttng_event_release,
1499         .unlocked_ioctl = lttng_event_ioctl,
1500 #ifdef CONFIG_COMPAT
1501         .compat_ioctl = lttng_event_ioctl,
1502 #endif
1503 };
1504
1505 static int put_u64(uint64_t val, unsigned long arg)
1506 {
1507         return put_user(val, (uint64_t __user *) arg);
1508 }
1509
1510 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1511                 unsigned int cmd, unsigned long arg)
1512 {
1513         struct lib_ring_buffer *buf = filp->private_data;
1514         struct channel *chan = buf->backend.chan;
1515         const struct lib_ring_buffer_config *config = &chan->backend.config;
1516         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1517         int ret;
1518
1519         if (atomic_read(&chan->record_disabled))
1520                 return -EIO;
1521
1522         switch (cmd) {
1523         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1524         {
1525                 uint64_t ts;
1526
1527                 ret = ops->timestamp_begin(config, buf, &ts);
1528                 if (ret < 0)
1529                         goto error;
1530                 return put_u64(ts, arg);
1531         }
1532         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1533         {
1534                 uint64_t ts;
1535
1536                 ret = ops->timestamp_end(config, buf, &ts);
1537                 if (ret < 0)
1538                         goto error;
1539                 return put_u64(ts, arg);
1540         }
1541         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1542         {
1543                 uint64_t ed;
1544
1545                 ret = ops->events_discarded(config, buf, &ed);
1546                 if (ret < 0)
1547                         goto error;
1548                 return put_u64(ed, arg);
1549         }
1550         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1551         {
1552                 uint64_t cs;
1553
1554                 ret = ops->content_size(config, buf, &cs);
1555                 if (ret < 0)
1556                         goto error;
1557                 return put_u64(cs, arg);
1558         }
1559         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1560         {
1561                 uint64_t ps;
1562
1563                 ret = ops->packet_size(config, buf, &ps);
1564                 if (ret < 0)
1565                         goto error;
1566                 return put_u64(ps, arg);
1567         }
1568         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1569         {
1570                 uint64_t si;
1571
1572                 ret = ops->stream_id(config, buf, &si);
1573                 if (ret < 0)
1574                         goto error;
1575                 return put_u64(si, arg);
1576         }
1577         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1578         {
1579                 uint64_t ts;
1580
1581                 ret = ops->current_timestamp(config, buf, &ts);
1582                 if (ret < 0)
1583                         goto error;
1584                 return put_u64(ts, arg);
1585         }
1586         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1587         {
1588                 uint64_t seq;
1589
1590                 ret = ops->sequence_number(config, buf, &seq);
1591                 if (ret < 0)
1592                         goto error;
1593                 return put_u64(seq, arg);
1594         }
1595         case LTTNG_RING_BUFFER_INSTANCE_ID:
1596         {
1597                 uint64_t id;
1598
1599                 ret = ops->instance_id(config, buf, &id);
1600                 if (ret < 0)
1601                         goto error;
1602                 return put_u64(id, arg);
1603         }
1604         default:
1605                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1606                                 cmd, arg);
1607         }
1608
1609 error:
1610         return -ENOSYS;
1611 }
1612
1613 #ifdef CONFIG_COMPAT
1614 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1615                 unsigned int cmd, unsigned long arg)
1616 {
1617         struct lib_ring_buffer *buf = filp->private_data;
1618         struct channel *chan = buf->backend.chan;
1619         const struct lib_ring_buffer_config *config = &chan->backend.config;
1620         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1621         int ret;
1622
1623         if (atomic_read(&chan->record_disabled))
1624                 return -EIO;
1625
1626         switch (cmd) {
1627         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1628         {
1629                 uint64_t ts;
1630
1631                 ret = ops->timestamp_begin(config, buf, &ts);
1632                 if (ret < 0)
1633                         goto error;
1634                 return put_u64(ts, arg);
1635         }
1636         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1637         {
1638                 uint64_t ts;
1639
1640                 ret = ops->timestamp_end(config, buf, &ts);
1641                 if (ret < 0)
1642                         goto error;
1643                 return put_u64(ts, arg);
1644         }
1645         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1646         {
1647                 uint64_t ed;
1648
1649                 ret = ops->events_discarded(config, buf, &ed);
1650                 if (ret < 0)
1651                         goto error;
1652                 return put_u64(ed, arg);
1653         }
1654         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1655         {
1656                 uint64_t cs;
1657
1658                 ret = ops->content_size(config, buf, &cs);
1659                 if (ret < 0)
1660                         goto error;
1661                 return put_u64(cs, arg);
1662         }
1663         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1664         {
1665                 uint64_t ps;
1666
1667                 ret = ops->packet_size(config, buf, &ps);
1668                 if (ret < 0)
1669                         goto error;
1670                 return put_u64(ps, arg);
1671         }
1672         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1673         {
1674                 uint64_t si;
1675
1676                 ret = ops->stream_id(config, buf, &si);
1677                 if (ret < 0)
1678                         goto error;
1679                 return put_u64(si, arg);
1680         }
1681         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1682         {
1683                 uint64_t ts;
1684
1685                 ret = ops->current_timestamp(config, buf, &ts);
1686                 if (ret < 0)
1687                         goto error;
1688                 return put_u64(ts, arg);
1689         }
1690         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1691         {
1692                 uint64_t seq;
1693
1694                 ret = ops->sequence_number(config, buf, &seq);
1695                 if (ret < 0)
1696                         goto error;
1697                 return put_u64(seq, arg);
1698         }
1699         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1700         {
1701                 uint64_t id;
1702
1703                 ret = ops->instance_id(config, buf, &id);
1704                 if (ret < 0)
1705                         goto error;
1706                 return put_u64(id, arg);
1707         }
1708         default:
1709                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1710                                 cmd, arg);
1711         }
1712
1713 error:
1714         return -ENOSYS;
1715 }
1716 #endif /* CONFIG_COMPAT */
1717
1718 static void lttng_stream_override_ring_buffer_fops(void)
1719 {
1720         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1721         lttng_stream_ring_buffer_file_operations.open =
1722                 lib_ring_buffer_file_operations.open;
1723         lttng_stream_ring_buffer_file_operations.release =
1724                 lib_ring_buffer_file_operations.release;
1725         lttng_stream_ring_buffer_file_operations.poll =
1726                 lib_ring_buffer_file_operations.poll;
1727         lttng_stream_ring_buffer_file_operations.splice_read =
1728                 lib_ring_buffer_file_operations.splice_read;
1729         lttng_stream_ring_buffer_file_operations.mmap =
1730                 lib_ring_buffer_file_operations.mmap;
1731         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1732                 lttng_stream_ring_buffer_ioctl;
1733         lttng_stream_ring_buffer_file_operations.llseek =
1734                 lib_ring_buffer_file_operations.llseek;
1735 #ifdef CONFIG_COMPAT
1736         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1737                 lttng_stream_ring_buffer_compat_ioctl;
1738 #endif
1739 }
1740
1741 int __init lttng_abi_init(void)
1742 {
1743         int ret = 0;
1744
1745         wrapper_vmalloc_sync_all();
1746         lttng_clock_ref();
1747         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1748                                         &lttng_fops, NULL);
1749
1750         if (!lttng_proc_dentry) {
1751                 printk(KERN_ERR "Error creating LTTng control file\n");
1752                 ret = -ENOMEM;
1753                 goto error;
1754         }
1755         lttng_stream_override_ring_buffer_fops();
1756         return 0;
1757
1758 error:
1759         lttng_clock_unref();
1760         return ret;
1761 }
1762
1763 /* No __exit annotation because used by init error path too. */
1764 void lttng_abi_exit(void)
1765 {
1766         lttng_clock_unref();
1767         if (lttng_proc_dentry)
1768                 remove_proc_entry("lttng", NULL);
1769 }