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         default:
 573                 return -ENOIOCTLCMD;
 574         }
 575 }
 576
 577 /*
 578  * Called when the last file reference is dropped.
 579  *
 580  * Big fat note: channels and events are invariant for the whole session after
 581  * their creation. So this session destruction also destroys all channel and
 582  * event structures specific to this session (they are not destroyed when their
 583  * individual file is released).
 584  */
 585 static
 586 int lttng_session_release(struct inode *inode, struct file *file)
 587 {
 588         struct lttng_session *session = file->private_data;
 589
 590         if (session)
 591                 lttng_session_destroy(session);
 592         return 0;
 593 }
 594
 595 static const struct file_operations lttng_session_fops = {
 596         .owner = THIS_MODULE,
 597         .release = lttng_session_release,
 598         .unlocked_ioctl = lttng_session_ioctl,
 599 #ifdef CONFIG_COMPAT
 600         .compat_ioctl = lttng_session_ioctl,
 601 #endif
 602 };
 603
 604 /**
 605  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 606  *      @filp: the file
 607  *      @wait: poll table
 608  *
 609  *      Handles the poll operations for the metadata channels.
 610  */
 611 static
 612 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 613                 poll_table *wait)
 614 {
 615         struct lttng_metadata_stream *stream = filp->private_data;
 616         struct lib_ring_buffer *buf = stream->priv;
 617         int finalized;
 618         unsigned int mask = 0;
 619
 620         if (filp->f_mode & FMODE_READ) {
 621                 poll_wait_set_exclusive(wait);
 622                 poll_wait(filp, &stream->read_wait, wait);
 623
 624                 finalized = stream->finalized;
 625
 626                 /*
 627                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 628                  * ordering finalized load before offsets loads.
 629                  */
 630                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 631
 632                 if (finalized)
 633                         mask |= POLLHUP;
 634
 635                 mutex_lock(&stream->metadata_cache->lock);
 636                 if (stream->metadata_cache->metadata_written >
 637                                 stream->metadata_out)
 638                         mask |= POLLIN;
 639                 mutex_unlock(&stream->metadata_cache->lock);
 640         }
 641
 642         return mask;
 643 }
 644
 645 static
 646 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 647                 unsigned int cmd, unsigned long arg)
 648 {
 649         struct lttng_metadata_stream *stream = filp->private_data;
 650
 651         stream->metadata_out = stream->metadata_in;
 652 }
 653
 654 static
 655 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 656                 unsigned int cmd, unsigned long arg)
 657 {
 658         int ret;
 659         struct lttng_metadata_stream *stream = filp->private_data;
 660         struct lib_ring_buffer *buf = stream->priv;
 661
 662         switch (cmd) {
 663         case RING_BUFFER_GET_NEXT_SUBBUF:
 664         {
 665                 struct lttng_metadata_stream *stream = filp->private_data;
 666                 struct lib_ring_buffer *buf = stream->priv;
 667                 struct channel *chan = buf->backend.chan;
 668
 669                 ret = lttng_metadata_output_channel(stream, chan);
 670                 if (ret > 0) {
 671                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 672                         ret = 0;
 673                 } else if (ret < 0)
 674                         goto err;
 675                 break;
 676         }
 677         case RING_BUFFER_GET_SUBBUF:
 678         {
 679                 /*
 680                  * Random access is not allowed for metadata channel.
 681                  */
 682                 return -ENOSYS;
 683         }
 684         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 685         case RING_BUFFER_FLUSH:
 686         {
 687                 struct lttng_metadata_stream *stream = filp->private_data;
 688                 struct lib_ring_buffer *buf = stream->priv;
 689                 struct channel *chan = buf->backend.chan;
 690
 691                 /*
 692                  * Before doing the actual ring buffer flush, write up to one
 693                  * packet of metadata in the ring buffer.
 694                  */
 695                 ret = lttng_metadata_output_channel(stream, chan);
 696                 if (ret < 0)
 697                         goto err;
 698                 break;
 699         }
 700         case RING_BUFFER_GET_METADATA_VERSION:
 701         {
 702                 struct lttng_metadata_stream *stream = filp->private_data;
 703
 704                 return put_u64(stream->version, arg);
 705         }
 706         default:
 707                 break;
 708         }
 709         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 710
 711         /* Performing lib ring buffer ioctl after our own. */
 712         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 713         if (ret < 0)
 714                 goto err;
 715
 716         switch (cmd) {
 717         case RING_BUFFER_PUT_NEXT_SUBBUF:
 718         {
 719                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 720                                 cmd, arg);
 721                 break;
 722         }
 723         default:
 724                 break;
 725         }
 726 err:
 727         return ret;
 728 }
 729
 730 #ifdef CONFIG_COMPAT
 731 static
 732 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 733                 unsigned int cmd, unsigned long arg)
 734 {
 735         int ret;
 736         struct lttng_metadata_stream *stream = filp->private_data;
 737         struct lib_ring_buffer *buf = stream->priv;
 738
 739         switch (cmd) {
 740         case RING_BUFFER_GET_NEXT_SUBBUF:
 741         {
 742                 struct lttng_metadata_stream *stream = filp->private_data;
 743                 struct lib_ring_buffer *buf = stream->priv;
 744                 struct channel *chan = buf->backend.chan;
 745
 746                 ret = lttng_metadata_output_channel(stream, chan);
 747                 if (ret > 0) {
 748                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 749                         ret = 0;
 750                 } else if (ret < 0)
 751                         goto err;
 752                 break;
 753         }
 754         case RING_BUFFER_GET_SUBBUF:
 755         {
 756                 /*
 757                  * Random access is not allowed for metadata channel.
 758                  */
 759                 return -ENOSYS;
 760         }
 761         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 762         case RING_BUFFER_FLUSH:
 763         {
 764                 struct lttng_metadata_stream *stream = filp->private_data;
 765                 struct lib_ring_buffer *buf = stream->priv;
 766                 struct channel *chan = buf->backend.chan;
 767
 768                 /*
 769                  * Before doing the actual ring buffer flush, write up to one
 770                  * packet of metadata in the ring buffer.
 771                  */
 772                 ret = lttng_metadata_output_channel(stream, chan);
 773                 if (ret < 0)
 774                         goto err;
 775                 break;
 776         }
 777         case RING_BUFFER_GET_METADATA_VERSION:
 778         {
 779                 struct lttng_metadata_stream *stream = filp->private_data;
 780
 781                 return put_u64(stream->version, arg);
 782         }
 783         default:
 784                 break;
 785         }
 786         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 787
 788         /* Performing lib ring buffer ioctl after our own. */
 789         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 790         if (ret < 0)
 791                 goto err;
 792
 793         switch (cmd) {
 794         case RING_BUFFER_PUT_NEXT_SUBBUF:
 795         {
 796                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 797                                 cmd, arg);
 798                 break;
 799         }
 800         default:
 801                 break;
 802         }
 803 err:
 804         return ret;
 805 }
 806 #endif
 807
 808 /*
 809  * This is not used by anonymous file descriptors. This code is left
 810  * there if we ever want to implement an inode with open() operation.
 811  */
 812 static
 813 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 814 {
 815         struct lttng_metadata_stream *stream = inode->i_private;
 816         struct lib_ring_buffer *buf = stream->priv;
 817
 818         file->private_data = buf;
 819         /*
 820          * Since life-time of metadata cache differs from that of
 821          * session, we need to keep our own reference on the transport.
 822          */
 823         if (!try_module_get(stream->transport->owner)) {
 824                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 825                 return -EBUSY;
 826         }
 827         return lib_ring_buffer_open(inode, file, buf);
 828 }
 829
 830 static
 831 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 832 {
 833         struct lttng_metadata_stream *stream = file->private_data;
 834         struct lib_ring_buffer *buf = stream->priv;
 835
 836         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 837         module_put(stream->transport->owner);
 838         return lib_ring_buffer_release(inode, file, buf);
 839 }
 840
 841 static
 842 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 843                 struct pipe_inode_info *pipe, size_t len,
 844                 unsigned int flags)
 845 {
 846         struct lttng_metadata_stream *stream = in->private_data;
 847         struct lib_ring_buffer *buf = stream->priv;
 848
 849         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 850                         flags, buf);
 851 }
 852
 853 static
 854 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 855                 struct vm_area_struct *vma)
 856 {
 857         struct lttng_metadata_stream *stream = filp->private_data;
 858         struct lib_ring_buffer *buf = stream->priv;
 859
 860         return lib_ring_buffer_mmap(filp, vma, buf);
 861 }
 862
 863 static
 864 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 865         .owner = THIS_MODULE,
 866         .open = lttng_metadata_ring_buffer_open,
 867         .release = lttng_metadata_ring_buffer_release,
 868         .poll = lttng_metadata_ring_buffer_poll,
 869         .splice_read = lttng_metadata_ring_buffer_splice_read,
 870         .mmap = lttng_metadata_ring_buffer_mmap,
 871         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 872         .llseek = vfs_lib_ring_buffer_no_llseek,
 873 #ifdef CONFIG_COMPAT
 874         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 875 #endif
 876 };
 877
 878 static
 879 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 880                 const struct file_operations *fops)
 881 {
 882         int stream_fd, ret;
 883         struct file *stream_file;
 884
 885         stream_fd = lttng_get_unused_fd();
 886         if (stream_fd < 0) {
 887                 ret = stream_fd;
 888                 goto fd_error;
 889         }
 890         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 891                         stream_priv, O_RDWR);
 892         if (IS_ERR(stream_file)) {
 893                 ret = PTR_ERR(stream_file);
 894                 goto file_error;
 895         }
 896         /*
 897          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 898          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 899          * file descriptor, so we set FMODE_PREAD here.
 900          */
 901         stream_file->f_mode |= FMODE_PREAD;
 902         fd_install(stream_fd, stream_file);
 903         /*
 904          * The stream holds a reference to the channel within the generic ring
 905          * buffer library, so no need to hold a refcount on the channel and
 906          * session files here.
 907          */
 908         return stream_fd;
 909
 910 file_error:
 911         put_unused_fd(stream_fd);
 912 fd_error:
 913         return ret;
 914 }
 915
 916 static
 917 int lttng_abi_open_stream(struct file *channel_file)
 918 {
 919         struct lttng_channel *channel = channel_file->private_data;
 920         struct lib_ring_buffer *buf;
 921         int ret;
 922         void *stream_priv;
 923
 924         buf = channel->ops->buffer_read_open(channel->chan);
 925         if (!buf)
 926                 return -ENOENT;
 927
 928         stream_priv = buf;
 929         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 930                         &lttng_stream_ring_buffer_file_operations);
 931         if (ret < 0)
 932                 goto fd_error;
 933
 934         return ret;
 935
 936 fd_error:
 937         channel->ops->buffer_read_close(buf);
 938         return ret;
 939 }
 940
 941 static
 942 int lttng_abi_open_metadata_stream(struct file *channel_file)
 943 {
 944         struct lttng_channel *channel = channel_file->private_data;
 945         struct lttng_session *session = channel->session;
 946         struct lib_ring_buffer *buf;
 947         int ret;
 948         struct lttng_metadata_stream *metadata_stream;
 949         void *stream_priv;
 950
 951         buf = channel->ops->buffer_read_open(channel->chan);
 952         if (!buf)
 953                 return -ENOENT;
 954
 955         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 956                         GFP_KERNEL);
 957         if (!metadata_stream) {
 958                 ret = -ENOMEM;
 959                 goto nomem;
 960         }
 961         metadata_stream->metadata_cache = session->metadata_cache;
 962         init_waitqueue_head(&metadata_stream->read_wait);
 963         metadata_stream->priv = buf;
 964         stream_priv = metadata_stream;
 965         metadata_stream->transport = channel->transport;
 966
 967         /*
 968          * Since life-time of metadata cache differs from that of
 969          * session, we need to keep our own reference on the transport.
 970          */
 971         if (!try_module_get(metadata_stream->transport->owner)) {
 972                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 973                 ret = -EINVAL;
 974                 goto notransport;
 975         }
 976
 977         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
 978                 ret = -EOVERFLOW;
 979                 goto kref_error;
 980         }
 981
 982         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 983                         &lttng_metadata_ring_buffer_file_operations);
 984         if (ret < 0)
 985                 goto fd_error;
 986
 987         list_add(&metadata_stream->list,
 988                 &session->metadata_cache->metadata_stream);
 989         return ret;
 990
 991 fd_error:
 992         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 993 kref_error:
 994         module_put(metadata_stream->transport->owner);
 995 notransport:
 996         kfree(metadata_stream);
 997 nomem:
 998         channel->ops->buffer_read_close(buf);
 999         return ret;
1000 }
1001
1002 static
1003 int lttng_abi_create_event(struct file *channel_file,
1004                            struct lttng_kernel_event *event_param)
1005 {
1006         struct lttng_channel *channel = channel_file->private_data;
1007         int event_fd, ret;
1008         struct file *event_file;
1009         void *priv;
1010
1011         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1012         switch (event_param->instrumentation) {
1013         case LTTNG_KERNEL_KRETPROBE:
1014                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1015                 break;
1016         case LTTNG_KERNEL_KPROBE:
1017                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1018                 break;
1019         case LTTNG_KERNEL_FUNCTION:
1020                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1021                 break;
1022         default:
1023                 break;
1024         }
1025         event_fd = lttng_get_unused_fd();
1026         if (event_fd < 0) {
1027                 ret = event_fd;
1028                 goto fd_error;
1029         }
1030         event_file = anon_inode_getfile("[lttng_event]",
1031                                         &lttng_event_fops,
1032                                         NULL, O_RDWR);
1033         if (IS_ERR(event_file)) {
1034                 ret = PTR_ERR(event_file);
1035                 goto file_error;
1036         }
1037         /* The event holds a reference on the channel */
1038         if (atomic_long_add_unless(&channel_file->f_count,
1039                 1, INT_MAX) == INT_MAX) {
1040                 ret = -EOVERFLOW;
1041                 goto refcount_error;
1042         }
1043         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1044                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1045                 struct lttng_enabler *enabler;
1046
1047                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1048                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1049                                 event_param, channel);
1050                 } else {
1051                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1052                                 event_param, channel);
1053                 }
1054                 priv = enabler;
1055         } else {
1056                 struct lttng_event *event;
1057
1058                 /*
1059                  * We tolerate no failure path after event creation. It
1060                  * will stay invariant for the rest of the session.
1061                  */
1062                 event = lttng_event_create(channel, event_param,
1063                                 NULL, NULL,
1064                                 event_param->instrumentation);
1065                 WARN_ON_ONCE(!event);
1066                 if (IS_ERR(event)) {
1067                         ret = PTR_ERR(event);
1068                         goto event_error;
1069                 }
1070                 priv = event;
1071         }
1072         event_file->private_data = priv;
1073         fd_install(event_fd, event_file);
1074         return event_fd;
1075
1076 event_error:
1077         atomic_long_dec(&channel_file->f_count);
1078 refcount_error:
1079         fput(event_file);
1080 file_error:
1081         put_unused_fd(event_fd);
1082 fd_error:
1083         return ret;
1084 }
1085
1086 /**
1087  *      lttng_channel_ioctl - lttng syscall through ioctl
1088  *
1089  *      @file: the file
1090  *      @cmd: the command
1091  *      @arg: command arg
1092  *
1093  *      This ioctl implements lttng commands:
1094  *      LTTNG_KERNEL_STREAM
1095  *              Returns an event stream file descriptor or failure.
1096  *              (typically, one event stream records events from one CPU)
1097  *      LTTNG_KERNEL_EVENT
1098  *              Returns an event file descriptor or failure.
1099  *      LTTNG_KERNEL_CONTEXT
1100  *              Prepend a context field to each event in the channel
1101  *      LTTNG_KERNEL_ENABLE
1102  *              Enable recording for events in this channel (weak enable)
1103  *      LTTNG_KERNEL_DISABLE
1104  *              Disable recording for events in this channel (strong disable)
1105  *
1106  * Channel and event file descriptors also hold a reference on the session.
1107  */
1108 static
1109 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1110 {
1111         struct lttng_channel *channel = file->private_data;
1112
1113         switch (cmd) {
1114         case LTTNG_KERNEL_OLD_STREAM:
1115         case LTTNG_KERNEL_STREAM:
1116                 return lttng_abi_open_stream(file);
1117         case LTTNG_KERNEL_OLD_EVENT:
1118         {
1119                 struct lttng_kernel_event *uevent_param;
1120                 struct lttng_kernel_old_event *old_uevent_param;
1121                 int ret;
1122
1123                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1124                                 GFP_KERNEL);
1125                 if (!uevent_param) {
1126                         ret = -ENOMEM;
1127                         goto old_event_end;
1128                 }
1129                 old_uevent_param = kmalloc(
1130                                 sizeof(struct lttng_kernel_old_event),
1131                                 GFP_KERNEL);
1132                 if (!old_uevent_param) {
1133                         ret = -ENOMEM;
1134                         goto old_event_error_free_param;
1135                 }
1136                 if (copy_from_user(old_uevent_param,
1137                                 (struct lttng_kernel_old_event __user *) arg,
1138                                 sizeof(struct lttng_kernel_old_event))) {
1139                         ret = -EFAULT;
1140                         goto old_event_error_free_old_param;
1141                 }
1142
1143                 memcpy(uevent_param->name, old_uevent_param->name,
1144                                 sizeof(uevent_param->name));
1145                 uevent_param->instrumentation =
1146                         old_uevent_param->instrumentation;
1147
1148                 switch (old_uevent_param->instrumentation) {
1149                 case LTTNG_KERNEL_KPROBE:
1150                         uevent_param->u.kprobe.addr =
1151                                 old_uevent_param->u.kprobe.addr;
1152                         uevent_param->u.kprobe.offset =
1153                                 old_uevent_param->u.kprobe.offset;
1154                         memcpy(uevent_param->u.kprobe.symbol_name,
1155                                 old_uevent_param->u.kprobe.symbol_name,
1156                                 sizeof(uevent_param->u.kprobe.symbol_name));
1157                         break;
1158                 case LTTNG_KERNEL_KRETPROBE:
1159                         uevent_param->u.kretprobe.addr =
1160                                 old_uevent_param->u.kretprobe.addr;
1161                         uevent_param->u.kretprobe.offset =
1162                                 old_uevent_param->u.kretprobe.offset;
1163                         memcpy(uevent_param->u.kretprobe.symbol_name,
1164                                 old_uevent_param->u.kretprobe.symbol_name,
1165                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1166                         break;
1167                 case LTTNG_KERNEL_FUNCTION:
1168                         memcpy(uevent_param->u.ftrace.symbol_name,
1169                                         old_uevent_param->u.ftrace.symbol_name,
1170                                         sizeof(uevent_param->u.ftrace.symbol_name));
1171                         break;
1172                 default:
1173                         break;
1174                 }
1175                 ret = lttng_abi_create_event(file, uevent_param);
1176
1177 old_event_error_free_old_param:
1178                 kfree(old_uevent_param);
1179 old_event_error_free_param:
1180                 kfree(uevent_param);
1181 old_event_end:
1182                 return ret;
1183         }
1184         case LTTNG_KERNEL_EVENT:
1185         {
1186                 struct lttng_kernel_event uevent_param;
1187
1188                 if (copy_from_user(&uevent_param,
1189                                 (struct lttng_kernel_event __user *) arg,
1190                                 sizeof(uevent_param)))
1191                         return -EFAULT;
1192                 return lttng_abi_create_event(file, &uevent_param);
1193         }
1194         case LTTNG_KERNEL_OLD_CONTEXT:
1195         {
1196                 struct lttng_kernel_context *ucontext_param;
1197                 struct lttng_kernel_old_context *old_ucontext_param;
1198                 int ret;
1199
1200                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1201                                 GFP_KERNEL);
1202                 if (!ucontext_param) {
1203                         ret = -ENOMEM;
1204                         goto old_ctx_end;
1205                 }
1206                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1207                                 GFP_KERNEL);
1208                 if (!old_ucontext_param) {
1209                         ret = -ENOMEM;
1210                         goto old_ctx_error_free_param;
1211                 }
1212
1213                 if (copy_from_user(old_ucontext_param,
1214                                 (struct lttng_kernel_old_context __user *) arg,
1215                                 sizeof(struct lttng_kernel_old_context))) {
1216                         ret = -EFAULT;
1217                         goto old_ctx_error_free_old_param;
1218                 }
1219                 ucontext_param->ctx = old_ucontext_param->ctx;
1220                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1221                                 sizeof(ucontext_param->padding));
1222                 /* only type that uses the union */
1223                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1224                         ucontext_param->u.perf_counter.type =
1225                                 old_ucontext_param->u.perf_counter.type;
1226                         ucontext_param->u.perf_counter.config =
1227                                 old_ucontext_param->u.perf_counter.config;
1228                         memcpy(ucontext_param->u.perf_counter.name,
1229                                 old_ucontext_param->u.perf_counter.name,
1230                                 sizeof(ucontext_param->u.perf_counter.name));
1231                 }
1232
1233                 ret = lttng_abi_add_context(file,
1234                                 ucontext_param,
1235                                 &channel->ctx, channel->session);
1236
1237 old_ctx_error_free_old_param:
1238                 kfree(old_ucontext_param);
1239 old_ctx_error_free_param:
1240                 kfree(ucontext_param);
1241 old_ctx_end:
1242                 return ret;
1243         }
1244         case LTTNG_KERNEL_CONTEXT:
1245         {
1246                 struct lttng_kernel_context ucontext_param;
1247
1248                 if (copy_from_user(&ucontext_param,
1249                                 (struct lttng_kernel_context __user *) arg,
1250                                 sizeof(ucontext_param)))
1251                         return -EFAULT;
1252                 return lttng_abi_add_context(file,
1253                                 &ucontext_param,
1254                                 &channel->ctx, channel->session);
1255         }
1256         case LTTNG_KERNEL_OLD_ENABLE:
1257         case LTTNG_KERNEL_ENABLE:
1258                 return lttng_channel_enable(channel);
1259         case LTTNG_KERNEL_OLD_DISABLE:
1260         case LTTNG_KERNEL_DISABLE:
1261                 return lttng_channel_disable(channel);
1262         case LTTNG_KERNEL_SYSCALL_MASK:
1263                 return lttng_channel_syscall_mask(channel,
1264                         (struct lttng_kernel_syscall_mask __user *) arg);
1265         default:
1266                 return -ENOIOCTLCMD;
1267         }
1268
1269 }
1270
1271 /**
1272  *      lttng_metadata_ioctl - lttng syscall through ioctl
1273  *
1274  *      @file: the file
1275  *      @cmd: the command
1276  *      @arg: command arg
1277  *
1278  *      This ioctl implements lttng commands:
1279  *      LTTNG_KERNEL_STREAM
1280  *              Returns an event stream file descriptor or failure.
1281  *
1282  * Channel and event file descriptors also hold a reference on the session.
1283  */
1284 static
1285 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1286 {
1287         switch (cmd) {
1288         case LTTNG_KERNEL_OLD_STREAM:
1289         case LTTNG_KERNEL_STREAM:
1290                 return lttng_abi_open_metadata_stream(file);
1291         default:
1292                 return -ENOIOCTLCMD;
1293         }
1294 }
1295
1296 /**
1297  *      lttng_channel_poll - lttng stream addition/removal monitoring
1298  *
1299  *      @file: the file
1300  *      @wait: poll table
1301  */
1302 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1303 {
1304         struct lttng_channel *channel = file->private_data;
1305         unsigned int mask = 0;
1306
1307         if (file->f_mode & FMODE_READ) {
1308                 poll_wait_set_exclusive(wait);
1309                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1310                           wait);
1311
1312                 if (channel->ops->is_disabled(channel->chan))
1313                         return POLLERR;
1314                 if (channel->ops->is_finalized(channel->chan))
1315                         return POLLHUP;
1316                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1317                         return POLLIN | POLLRDNORM;
1318                 return 0;
1319         }
1320         return mask;
1321
1322 }
1323
1324 static
1325 int lttng_channel_release(struct inode *inode, struct file *file)
1326 {
1327         struct lttng_channel *channel = file->private_data;
1328
1329         if (channel)
1330                 fput(channel->session->file);
1331         return 0;
1332 }
1333
1334 static
1335 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1336 {
1337         struct lttng_channel *channel = file->private_data;
1338
1339         if (channel) {
1340                 fput(channel->session->file);
1341                 lttng_metadata_channel_destroy(channel);
1342         }
1343
1344         return 0;
1345 }
1346
1347 static const struct file_operations lttng_channel_fops = {
1348         .owner = THIS_MODULE,
1349         .release = lttng_channel_release,
1350         .poll = lttng_channel_poll,
1351         .unlocked_ioctl = lttng_channel_ioctl,
1352 #ifdef CONFIG_COMPAT
1353         .compat_ioctl = lttng_channel_ioctl,
1354 #endif
1355 };
1356
1357 static const struct file_operations lttng_metadata_fops = {
1358         .owner = THIS_MODULE,
1359         .release = lttng_metadata_channel_release,
1360         .unlocked_ioctl = lttng_metadata_ioctl,
1361 #ifdef CONFIG_COMPAT
1362         .compat_ioctl = lttng_metadata_ioctl,
1363 #endif
1364 };
1365
1366 /**
1367  *      lttng_event_ioctl - lttng syscall through ioctl
1368  *
1369  *      @file: the file
1370  *      @cmd: the command
1371  *      @arg: command arg
1372  *
1373  *      This ioctl implements lttng commands:
1374  *      LTTNG_KERNEL_CONTEXT
1375  *              Prepend a context field to each record of this event
1376  *      LTTNG_KERNEL_ENABLE
1377  *              Enable recording for this event (weak enable)
1378  *      LTTNG_KERNEL_DISABLE
1379  *              Disable recording for this event (strong disable)
1380  */
1381 static
1382 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1383 {
1384         struct lttng_event *event;
1385         struct lttng_enabler *enabler;
1386         enum lttng_event_type *evtype = file->private_data;
1387
1388         switch (cmd) {
1389         case LTTNG_KERNEL_OLD_CONTEXT:
1390         {
1391                 /* Not implemented */
1392                 return -ENOSYS;
1393         }
1394         case LTTNG_KERNEL_CONTEXT:
1395         {
1396                 /* Not implemented */
1397                 return -ENOSYS;
1398         }
1399         case LTTNG_KERNEL_OLD_ENABLE:
1400         case LTTNG_KERNEL_ENABLE:
1401                 switch (*evtype) {
1402                 case LTTNG_TYPE_EVENT:
1403                         event = file->private_data;
1404                         return lttng_event_enable(event);
1405                 case LTTNG_TYPE_ENABLER:
1406                         enabler = file->private_data;
1407                         return lttng_enabler_enable(enabler);
1408                 default:
1409                         WARN_ON_ONCE(1);
1410                         return -ENOSYS;
1411                 }
1412         case LTTNG_KERNEL_OLD_DISABLE:
1413         case LTTNG_KERNEL_DISABLE:
1414                 switch (*evtype) {
1415                 case LTTNG_TYPE_EVENT:
1416                         event = file->private_data;
1417                         return lttng_event_disable(event);
1418                 case LTTNG_TYPE_ENABLER:
1419                         enabler = file->private_data;
1420                         return lttng_enabler_disable(enabler);
1421                 default:
1422                         WARN_ON_ONCE(1);
1423                         return -ENOSYS;
1424                 }
1425         case LTTNG_KERNEL_FILTER:
1426                 switch (*evtype) {
1427                 case LTTNG_TYPE_EVENT:
1428                         return -EINVAL;
1429                 case LTTNG_TYPE_ENABLER:
1430                 {
1431                         enabler = file->private_data;
1432                         return lttng_enabler_attach_bytecode(enabler,
1433                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1434                 }
1435
1436                 }
1437         default:
1438                 return -ENOIOCTLCMD;
1439         }
1440 }
1441
1442 static
1443 int lttng_event_release(struct inode *inode, struct file *file)
1444 {
1445         struct lttng_event *event;
1446         struct lttng_enabler *enabler;
1447         enum lttng_event_type *evtype = file->private_data;
1448
1449         if (!evtype)
1450                 return 0;
1451
1452         switch (*evtype) {
1453         case LTTNG_TYPE_EVENT:
1454                 event = file->private_data;
1455                 if (event)
1456                         fput(event->chan->file);
1457                 break;
1458         case LTTNG_TYPE_ENABLER:
1459                 enabler = file->private_data;
1460                 if (enabler)
1461                         fput(enabler->chan->file);
1462                 break;
1463         default:
1464                 WARN_ON_ONCE(1);
1465                 break;
1466         }
1467
1468         return 0;
1469 }
1470
1471 /* TODO: filter control ioctl */
1472 static const struct file_operations lttng_event_fops = {
1473         .owner = THIS_MODULE,
1474         .release = lttng_event_release,
1475         .unlocked_ioctl = lttng_event_ioctl,
1476 #ifdef CONFIG_COMPAT
1477         .compat_ioctl = lttng_event_ioctl,
1478 #endif
1479 };
1480
1481 static int put_u64(uint64_t val, unsigned long arg)
1482 {
1483         return put_user(val, (uint64_t __user *) arg);
1484 }
1485
1486 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1487                 unsigned int cmd, unsigned long arg)
1488 {
1489         struct lib_ring_buffer *buf = filp->private_data;
1490         struct channel *chan = buf->backend.chan;
1491         const struct lib_ring_buffer_config *config = &chan->backend.config;
1492         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1493         int ret;
1494
1495         if (atomic_read(&chan->record_disabled))
1496                 return -EIO;
1497
1498         switch (cmd) {
1499         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1500         {
1501                 uint64_t ts;
1502
1503                 ret = ops->timestamp_begin(config, buf, &ts);
1504                 if (ret < 0)
1505                         goto error;
1506                 return put_u64(ts, arg);
1507         }
1508         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1509         {
1510                 uint64_t ts;
1511
1512                 ret = ops->timestamp_end(config, buf, &ts);
1513                 if (ret < 0)
1514                         goto error;
1515                 return put_u64(ts, arg);
1516         }
1517         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1518         {
1519                 uint64_t ed;
1520
1521                 ret = ops->events_discarded(config, buf, &ed);
1522                 if (ret < 0)
1523                         goto error;
1524                 return put_u64(ed, arg);
1525         }
1526         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1527         {
1528                 uint64_t cs;
1529
1530                 ret = ops->content_size(config, buf, &cs);
1531                 if (ret < 0)
1532                         goto error;
1533                 return put_u64(cs, arg);
1534         }
1535         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1536         {
1537                 uint64_t ps;
1538
1539                 ret = ops->packet_size(config, buf, &ps);
1540                 if (ret < 0)
1541                         goto error;
1542                 return put_u64(ps, arg);
1543         }
1544         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1545         {
1546                 uint64_t si;
1547
1548                 ret = ops->stream_id(config, buf, &si);
1549                 if (ret < 0)
1550                         goto error;
1551                 return put_u64(si, arg);
1552         }
1553         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1554         {
1555                 uint64_t ts;
1556
1557                 ret = ops->current_timestamp(config, buf, &ts);
1558                 if (ret < 0)
1559                         goto error;
1560                 return put_u64(ts, arg);
1561         }
1562         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1563         {
1564                 uint64_t seq;
1565
1566                 ret = ops->sequence_number(config, buf, &seq);
1567                 if (ret < 0)
1568                         goto error;
1569                 return put_u64(seq, arg);
1570         }
1571         case LTTNG_RING_BUFFER_INSTANCE_ID:
1572         {
1573                 uint64_t id;
1574
1575                 ret = ops->instance_id(config, buf, &id);
1576                 if (ret < 0)
1577                         goto error;
1578                 return put_u64(id, arg);
1579         }
1580         default:
1581                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1582                                 cmd, arg);
1583         }
1584
1585 error:
1586         return -ENOSYS;
1587 }
1588
1589 #ifdef CONFIG_COMPAT
1590 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1591                 unsigned int cmd, unsigned long arg)
1592 {
1593         struct lib_ring_buffer *buf = filp->private_data;
1594         struct channel *chan = buf->backend.chan;
1595         const struct lib_ring_buffer_config *config = &chan->backend.config;
1596         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1597         int ret;
1598
1599         if (atomic_read(&chan->record_disabled))
1600                 return -EIO;
1601
1602         switch (cmd) {
1603         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1604         {
1605                 uint64_t ts;
1606
1607                 ret = ops->timestamp_begin(config, buf, &ts);
1608                 if (ret < 0)
1609                         goto error;
1610                 return put_u64(ts, arg);
1611         }
1612         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1613         {
1614                 uint64_t ts;
1615
1616                 ret = ops->timestamp_end(config, buf, &ts);
1617                 if (ret < 0)
1618                         goto error;
1619                 return put_u64(ts, arg);
1620         }
1621         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1622         {
1623                 uint64_t ed;
1624
1625                 ret = ops->events_discarded(config, buf, &ed);
1626                 if (ret < 0)
1627                         goto error;
1628                 return put_u64(ed, arg);
1629         }
1630         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1631         {
1632                 uint64_t cs;
1633
1634                 ret = ops->content_size(config, buf, &cs);
1635                 if (ret < 0)
1636                         goto error;
1637                 return put_u64(cs, arg);
1638         }
1639         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1640         {
1641                 uint64_t ps;
1642
1643                 ret = ops->packet_size(config, buf, &ps);
1644                 if (ret < 0)
1645                         goto error;
1646                 return put_u64(ps, arg);
1647         }
1648         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1649         {
1650                 uint64_t si;
1651
1652                 ret = ops->stream_id(config, buf, &si);
1653                 if (ret < 0)
1654                         goto error;
1655                 return put_u64(si, arg);
1656         }
1657         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1658         {
1659                 uint64_t ts;
1660
1661                 ret = ops->current_timestamp(config, buf, &ts);
1662                 if (ret < 0)
1663                         goto error;
1664                 return put_u64(ts, arg);
1665         }
1666         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1667         {
1668                 uint64_t seq;
1669
1670                 ret = ops->sequence_number(config, buf, &seq);
1671                 if (ret < 0)
1672                         goto error;
1673                 return put_u64(seq, arg);
1674         }
1675         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1676         {
1677                 uint64_t id;
1678
1679                 ret = ops->instance_id(config, buf, &id);
1680                 if (ret < 0)
1681                         goto error;
1682                 return put_u64(id, arg);
1683         }
1684         default:
1685                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1686                                 cmd, arg);
1687         }
1688
1689 error:
1690         return -ENOSYS;
1691 }
1692 #endif /* CONFIG_COMPAT */
1693
1694 static void lttng_stream_override_ring_buffer_fops(void)
1695 {
1696         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1697         lttng_stream_ring_buffer_file_operations.open =
1698                 lib_ring_buffer_file_operations.open;
1699         lttng_stream_ring_buffer_file_operations.release =
1700                 lib_ring_buffer_file_operations.release;
1701         lttng_stream_ring_buffer_file_operations.poll =
1702                 lib_ring_buffer_file_operations.poll;
1703         lttng_stream_ring_buffer_file_operations.splice_read =
1704                 lib_ring_buffer_file_operations.splice_read;
1705         lttng_stream_ring_buffer_file_operations.mmap =
1706                 lib_ring_buffer_file_operations.mmap;
1707         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1708                 lttng_stream_ring_buffer_ioctl;
1709         lttng_stream_ring_buffer_file_operations.llseek =
1710                 lib_ring_buffer_file_operations.llseek;
1711 #ifdef CONFIG_COMPAT
1712         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1713                 lttng_stream_ring_buffer_compat_ioctl;
1714 #endif
1715 }
1716
1717 int __init lttng_abi_init(void)
1718 {
1719         int ret = 0;
1720
1721         wrapper_vmalloc_sync_all();
1722         lttng_clock_ref();
1723         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1724                                         &lttng_fops, NULL);
1725
1726         if (!lttng_proc_dentry) {
1727                 printk(KERN_ERR "Error creating LTTng control file\n");
1728                 ret = -ENOMEM;
1729                 goto error;
1730         }
1731         lttng_stream_override_ring_buffer_fops();
1732         return 0;
1733
1734 error:
1735         lttng_clock_unref();
1736         return ret;
1737 }
1738
1739 /* No __exit annotation because used by init error path too. */
1740 void lttng_abi_exit(void)
1741 {
1742         lttng_clock_unref();
1743         if (lttng_proc_dentry)
1744                 remove_proc_entry("lttng", NULL);
1745 }