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                 goto kref_error;
1003         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1004                         &lttng_metadata_ring_buffer_file_operations);
1005         if (ret < 0)
1006                 goto fd_error;
1007
1008         list_add(&metadata_stream->list,
1009                 &session->metadata_cache->metadata_stream);
1010         return ret;
1011
1012 fd_error:
1013         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1014 kref_error:
1015         module_put(metadata_stream->transport->owner);
1016 notransport:
1017         kfree(metadata_stream);
1018 nomem:
1019         channel->ops->buffer_read_close(buf);
1020         return ret;
1021 }
1022
1023 static
1024 int lttng_abi_create_event(struct file *channel_file,
1025                            struct lttng_kernel_event *event_param)
1026 {
1027         struct lttng_channel *channel = channel_file->private_data;
1028         int event_fd, ret;
1029         struct file *event_file;
1030         void *priv;
1031
1032         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1033         switch (event_param->instrumentation) {
1034         case LTTNG_KERNEL_KRETPROBE:
1035                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1036                 break;
1037         case LTTNG_KERNEL_KPROBE:
1038                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1039                 break;
1040         case LTTNG_KERNEL_FUNCTION:
1041                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1042                 break;
1043         default:
1044                 break;
1045         }
1046         event_fd = lttng_get_unused_fd();
1047         if (event_fd < 0) {
1048                 ret = event_fd;
1049                 goto fd_error;
1050         }
1051         event_file = anon_inode_getfile("[lttng_event]",
1052                                         &lttng_event_fops,
1053                                         NULL, O_RDWR);
1054         if (IS_ERR(event_file)) {
1055                 ret = PTR_ERR(event_file);
1056                 goto file_error;
1057         }
1058         /* The event holds a reference on the channel */
1059         if (atomic_long_add_unless(&channel_file->f_count,
1060                 1, INT_MAX) == INT_MAX) {
1061                 ret = -EOVERFLOW;
1062                 goto refcount_error;
1063         }
1064         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1065                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1066                 struct lttng_enabler *enabler;
1067
1068                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1069                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1070                                 event_param, channel);
1071                 } else {
1072                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1073                                 event_param, channel);
1074                 }
1075                 priv = enabler;
1076         } else {
1077                 struct lttng_event *event;
1078
1079                 /*
1080                  * We tolerate no failure path after event creation. It
1081                  * will stay invariant for the rest of the session.
1082                  */
1083                 event = lttng_event_create(channel, event_param,
1084                                 NULL, NULL,
1085                                 event_param->instrumentation);
1086                 WARN_ON_ONCE(!event);
1087                 if (IS_ERR(event)) {
1088                         ret = PTR_ERR(event);
1089                         goto event_error;
1090                 }
1091                 priv = event;
1092         }
1093         event_file->private_data = priv;
1094         fd_install(event_fd, event_file);
1095         return event_fd;
1096
1097 event_error:
1098         atomic_long_dec(&channel_file->f_count);
1099 refcount_error:
1100         fput(event_file);
1101 file_error:
1102         put_unused_fd(event_fd);
1103 fd_error:
1104         return ret;
1105 }
1106
1107 /**
1108  *      lttng_channel_ioctl - lttng syscall through ioctl
1109  *
1110  *      @file: the file
1111  *      @cmd: the command
1112  *      @arg: command arg
1113  *
1114  *      This ioctl implements lttng commands:
1115  *      LTTNG_KERNEL_STREAM
1116  *              Returns an event stream file descriptor or failure.
1117  *              (typically, one event stream records events from one CPU)
1118  *      LTTNG_KERNEL_EVENT
1119  *              Returns an event file descriptor or failure.
1120  *      LTTNG_KERNEL_CONTEXT
1121  *              Prepend a context field to each event in the channel
1122  *      LTTNG_KERNEL_ENABLE
1123  *              Enable recording for events in this channel (weak enable)
1124  *      LTTNG_KERNEL_DISABLE
1125  *              Disable recording for events in this channel (strong disable)
1126  *
1127  * Channel and event file descriptors also hold a reference on the session.
1128  */
1129 static
1130 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1131 {
1132         struct lttng_channel *channel = file->private_data;
1133
1134         switch (cmd) {
1135         case LTTNG_KERNEL_OLD_STREAM:
1136         case LTTNG_KERNEL_STREAM:
1137                 return lttng_abi_open_stream(file);
1138         case LTTNG_KERNEL_OLD_EVENT:
1139         {
1140                 struct lttng_kernel_event *uevent_param;
1141                 struct lttng_kernel_old_event *old_uevent_param;
1142                 int ret;
1143
1144                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1145                                 GFP_KERNEL);
1146                 if (!uevent_param) {
1147                         ret = -ENOMEM;
1148                         goto old_event_end;
1149                 }
1150                 old_uevent_param = kmalloc(
1151                                 sizeof(struct lttng_kernel_old_event),
1152                                 GFP_KERNEL);
1153                 if (!old_uevent_param) {
1154                         ret = -ENOMEM;
1155                         goto old_event_error_free_param;
1156                 }
1157                 if (copy_from_user(old_uevent_param,
1158                                 (struct lttng_kernel_old_event __user *) arg,
1159                                 sizeof(struct lttng_kernel_old_event))) {
1160                         ret = -EFAULT;
1161                         goto old_event_error_free_old_param;
1162                 }
1163
1164                 memcpy(uevent_param->name, old_uevent_param->name,
1165                                 sizeof(uevent_param->name));
1166                 uevent_param->instrumentation =
1167                         old_uevent_param->instrumentation;
1168
1169                 switch (old_uevent_param->instrumentation) {
1170                 case LTTNG_KERNEL_KPROBE:
1171                         uevent_param->u.kprobe.addr =
1172                                 old_uevent_param->u.kprobe.addr;
1173                         uevent_param->u.kprobe.offset =
1174                                 old_uevent_param->u.kprobe.offset;
1175                         memcpy(uevent_param->u.kprobe.symbol_name,
1176                                 old_uevent_param->u.kprobe.symbol_name,
1177                                 sizeof(uevent_param->u.kprobe.symbol_name));
1178                         break;
1179                 case LTTNG_KERNEL_KRETPROBE:
1180                         uevent_param->u.kretprobe.addr =
1181                                 old_uevent_param->u.kretprobe.addr;
1182                         uevent_param->u.kretprobe.offset =
1183                                 old_uevent_param->u.kretprobe.offset;
1184                         memcpy(uevent_param->u.kretprobe.symbol_name,
1185                                 old_uevent_param->u.kretprobe.symbol_name,
1186                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1187                         break;
1188                 case LTTNG_KERNEL_FUNCTION:
1189                         memcpy(uevent_param->u.ftrace.symbol_name,
1190                                         old_uevent_param->u.ftrace.symbol_name,
1191                                         sizeof(uevent_param->u.ftrace.symbol_name));
1192                         break;
1193                 default:
1194                         break;
1195                 }
1196                 ret = lttng_abi_create_event(file, uevent_param);
1197
1198 old_event_error_free_old_param:
1199                 kfree(old_uevent_param);
1200 old_event_error_free_param:
1201                 kfree(uevent_param);
1202 old_event_end:
1203                 return ret;
1204         }
1205         case LTTNG_KERNEL_EVENT:
1206         {
1207                 struct lttng_kernel_event uevent_param;
1208
1209                 if (copy_from_user(&uevent_param,
1210                                 (struct lttng_kernel_event __user *) arg,
1211                                 sizeof(uevent_param)))
1212                         return -EFAULT;
1213                 return lttng_abi_create_event(file, &uevent_param);
1214         }
1215         case LTTNG_KERNEL_OLD_CONTEXT:
1216         {
1217                 struct lttng_kernel_context *ucontext_param;
1218                 struct lttng_kernel_old_context *old_ucontext_param;
1219                 int ret;
1220
1221                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1222                                 GFP_KERNEL);
1223                 if (!ucontext_param) {
1224                         ret = -ENOMEM;
1225                         goto old_ctx_end;
1226                 }
1227                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1228                                 GFP_KERNEL);
1229                 if (!old_ucontext_param) {
1230                         ret = -ENOMEM;
1231                         goto old_ctx_error_free_param;
1232                 }
1233
1234                 if (copy_from_user(old_ucontext_param,
1235                                 (struct lttng_kernel_old_context __user *) arg,
1236                                 sizeof(struct lttng_kernel_old_context))) {
1237                         ret = -EFAULT;
1238                         goto old_ctx_error_free_old_param;
1239                 }
1240                 ucontext_param->ctx = old_ucontext_param->ctx;
1241                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1242                                 sizeof(ucontext_param->padding));
1243                 /* only type that uses the union */
1244                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1245                         ucontext_param->u.perf_counter.type =
1246                                 old_ucontext_param->u.perf_counter.type;
1247                         ucontext_param->u.perf_counter.config =
1248                                 old_ucontext_param->u.perf_counter.config;
1249                         memcpy(ucontext_param->u.perf_counter.name,
1250                                 old_ucontext_param->u.perf_counter.name,
1251                                 sizeof(ucontext_param->u.perf_counter.name));
1252                 }
1253
1254                 ret = lttng_abi_add_context(file,
1255                                 ucontext_param,
1256                                 &channel->ctx, channel->session);
1257
1258 old_ctx_error_free_old_param:
1259                 kfree(old_ucontext_param);
1260 old_ctx_error_free_param:
1261                 kfree(ucontext_param);
1262 old_ctx_end:
1263                 return ret;
1264         }
1265         case LTTNG_KERNEL_CONTEXT:
1266         {
1267                 struct lttng_kernel_context ucontext_param;
1268
1269                 if (copy_from_user(&ucontext_param,
1270                                 (struct lttng_kernel_context __user *) arg,
1271                                 sizeof(ucontext_param)))
1272                         return -EFAULT;
1273                 return lttng_abi_add_context(file,
1274                                 &ucontext_param,
1275                                 &channel->ctx, channel->session);
1276         }
1277         case LTTNG_KERNEL_OLD_ENABLE:
1278         case LTTNG_KERNEL_ENABLE:
1279                 return lttng_channel_enable(channel);
1280         case LTTNG_KERNEL_OLD_DISABLE:
1281         case LTTNG_KERNEL_DISABLE:
1282                 return lttng_channel_disable(channel);
1283         case LTTNG_KERNEL_SYSCALL_MASK:
1284                 return lttng_channel_syscall_mask(channel,
1285                         (struct lttng_kernel_syscall_mask __user *) arg);
1286         default:
1287                 return -ENOIOCTLCMD;
1288         }
1289
1290 }
1291
1292 /**
1293  *      lttng_metadata_ioctl - lttng syscall through ioctl
1294  *
1295  *      @file: the file
1296  *      @cmd: the command
1297  *      @arg: command arg
1298  *
1299  *      This ioctl implements lttng commands:
1300  *      LTTNG_KERNEL_STREAM
1301  *              Returns an event stream file descriptor or failure.
1302  *
1303  * Channel and event file descriptors also hold a reference on the session.
1304  */
1305 static
1306 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1307 {
1308         switch (cmd) {
1309         case LTTNG_KERNEL_OLD_STREAM:
1310         case LTTNG_KERNEL_STREAM:
1311                 return lttng_abi_open_metadata_stream(file);
1312         default:
1313                 return -ENOIOCTLCMD;
1314         }
1315 }
1316
1317 /**
1318  *      lttng_channel_poll - lttng stream addition/removal monitoring
1319  *
1320  *      @file: the file
1321  *      @wait: poll table
1322  */
1323 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1324 {
1325         struct lttng_channel *channel = file->private_data;
1326         unsigned int mask = 0;
1327
1328         if (file->f_mode & FMODE_READ) {
1329                 poll_wait_set_exclusive(wait);
1330                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1331                           wait);
1332
1333                 if (channel->ops->is_disabled(channel->chan))
1334                         return POLLERR;
1335                 if (channel->ops->is_finalized(channel->chan))
1336                         return POLLHUP;
1337                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1338                         return POLLIN | POLLRDNORM;
1339                 return 0;
1340         }
1341         return mask;
1342
1343 }
1344
1345 static
1346 int lttng_channel_release(struct inode *inode, struct file *file)
1347 {
1348         struct lttng_channel *channel = file->private_data;
1349
1350         if (channel)
1351                 fput(channel->session->file);
1352         return 0;
1353 }
1354
1355 static
1356 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1357 {
1358         struct lttng_channel *channel = file->private_data;
1359
1360         if (channel) {
1361                 fput(channel->session->file);
1362                 lttng_metadata_channel_destroy(channel);
1363         }
1364
1365         return 0;
1366 }
1367
1368 static const struct file_operations lttng_channel_fops = {
1369         .owner = THIS_MODULE,
1370         .release = lttng_channel_release,
1371         .poll = lttng_channel_poll,
1372         .unlocked_ioctl = lttng_channel_ioctl,
1373 #ifdef CONFIG_COMPAT
1374         .compat_ioctl = lttng_channel_ioctl,
1375 #endif
1376 };
1377
1378 static const struct file_operations lttng_metadata_fops = {
1379         .owner = THIS_MODULE,
1380         .release = lttng_metadata_channel_release,
1381         .unlocked_ioctl = lttng_metadata_ioctl,
1382 #ifdef CONFIG_COMPAT
1383         .compat_ioctl = lttng_metadata_ioctl,
1384 #endif
1385 };
1386
1387 /**
1388  *      lttng_event_ioctl - lttng syscall through ioctl
1389  *
1390  *      @file: the file
1391  *      @cmd: the command
1392  *      @arg: command arg
1393  *
1394  *      This ioctl implements lttng commands:
1395  *      LTTNG_KERNEL_CONTEXT
1396  *              Prepend a context field to each record of this event
1397  *      LTTNG_KERNEL_ENABLE
1398  *              Enable recording for this event (weak enable)
1399  *      LTTNG_KERNEL_DISABLE
1400  *              Disable recording for this event (strong disable)
1401  */
1402 static
1403 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1404 {
1405         struct lttng_event *event;
1406         struct lttng_enabler *enabler;
1407         enum lttng_event_type *evtype = file->private_data;
1408
1409         switch (cmd) {
1410         case LTTNG_KERNEL_OLD_CONTEXT:
1411         {
1412                 /* Not implemented */
1413                 return -ENOSYS;
1414         }
1415         case LTTNG_KERNEL_CONTEXT:
1416         {
1417                 /* Not implemented */
1418                 return -ENOSYS;
1419         }
1420         case LTTNG_KERNEL_OLD_ENABLE:
1421         case LTTNG_KERNEL_ENABLE:
1422                 switch (*evtype) {
1423                 case LTTNG_TYPE_EVENT:
1424                         event = file->private_data;
1425                         return lttng_event_enable(event);
1426                 case LTTNG_TYPE_ENABLER:
1427                         enabler = file->private_data;
1428                         return lttng_enabler_enable(enabler);
1429                 default:
1430                         WARN_ON_ONCE(1);
1431                         return -ENOSYS;
1432                 }
1433         case LTTNG_KERNEL_OLD_DISABLE:
1434         case LTTNG_KERNEL_DISABLE:
1435                 switch (*evtype) {
1436                 case LTTNG_TYPE_EVENT:
1437                         event = file->private_data;
1438                         return lttng_event_disable(event);
1439                 case LTTNG_TYPE_ENABLER:
1440                         enabler = file->private_data;
1441                         return lttng_enabler_disable(enabler);
1442                 default:
1443                         WARN_ON_ONCE(1);
1444                         return -ENOSYS;
1445                 }
1446         case LTTNG_KERNEL_FILTER:
1447                 switch (*evtype) {
1448                 case LTTNG_TYPE_EVENT:
1449                         return -EINVAL;
1450                 case LTTNG_TYPE_ENABLER:
1451                 {
1452                         enabler = file->private_data;
1453                         return lttng_enabler_attach_bytecode(enabler,
1454                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1455                 }
1456
1457                 }
1458         default:
1459                 return -ENOIOCTLCMD;
1460         }
1461 }
1462
1463 static
1464 int lttng_event_release(struct inode *inode, struct file *file)
1465 {
1466         struct lttng_event *event;
1467         struct lttng_enabler *enabler;
1468         enum lttng_event_type *evtype = file->private_data;
1469
1470         if (!evtype)
1471                 return 0;
1472
1473         switch (*evtype) {
1474         case LTTNG_TYPE_EVENT:
1475                 event = file->private_data;
1476                 if (event)
1477                         fput(event->chan->file);
1478                 break;
1479         case LTTNG_TYPE_ENABLER:
1480                 enabler = file->private_data;
1481                 if (enabler)
1482                         fput(enabler->chan->file);
1483                 break;
1484         default:
1485                 WARN_ON_ONCE(1);
1486                 break;
1487         }
1488
1489         return 0;
1490 }
1491
1492 /* TODO: filter control ioctl */
1493 static const struct file_operations lttng_event_fops = {
1494         .owner = THIS_MODULE,
1495         .release = lttng_event_release,
1496         .unlocked_ioctl = lttng_event_ioctl,
1497 #ifdef CONFIG_COMPAT
1498         .compat_ioctl = lttng_event_ioctl,
1499 #endif
1500 };
1501
1502 static int put_u64(uint64_t val, unsigned long arg)
1503 {
1504         return put_user(val, (uint64_t __user *) arg);
1505 }
1506
1507 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1508                 unsigned int cmd, unsigned long arg)
1509 {
1510         struct lib_ring_buffer *buf = filp->private_data;
1511         struct channel *chan = buf->backend.chan;
1512         const struct lib_ring_buffer_config *config = &chan->backend.config;
1513         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1514         int ret;
1515
1516         if (atomic_read(&chan->record_disabled))
1517                 return -EIO;
1518
1519         switch (cmd) {
1520         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1521         {
1522                 uint64_t ts;
1523
1524                 ret = ops->timestamp_begin(config, buf, &ts);
1525                 if (ret < 0)
1526                         goto error;
1527                 return put_u64(ts, arg);
1528         }
1529         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1530         {
1531                 uint64_t ts;
1532
1533                 ret = ops->timestamp_end(config, buf, &ts);
1534                 if (ret < 0)
1535                         goto error;
1536                 return put_u64(ts, arg);
1537         }
1538         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1539         {
1540                 uint64_t ed;
1541
1542                 ret = ops->events_discarded(config, buf, &ed);
1543                 if (ret < 0)
1544                         goto error;
1545                 return put_u64(ed, arg);
1546         }
1547         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1548         {
1549                 uint64_t cs;
1550
1551                 ret = ops->content_size(config, buf, &cs);
1552                 if (ret < 0)
1553                         goto error;
1554                 return put_u64(cs, arg);
1555         }
1556         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1557         {
1558                 uint64_t ps;
1559
1560                 ret = ops->packet_size(config, buf, &ps);
1561                 if (ret < 0)
1562                         goto error;
1563                 return put_u64(ps, arg);
1564         }
1565         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1566         {
1567                 uint64_t si;
1568
1569                 ret = ops->stream_id(config, buf, &si);
1570                 if (ret < 0)
1571                         goto error;
1572                 return put_u64(si, arg);
1573         }
1574         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1575         {
1576                 uint64_t ts;
1577
1578                 ret = ops->current_timestamp(config, buf, &ts);
1579                 if (ret < 0)
1580                         goto error;
1581                 return put_u64(ts, arg);
1582         }
1583         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1584         {
1585                 uint64_t seq;
1586
1587                 ret = ops->sequence_number(config, buf, &seq);
1588                 if (ret < 0)
1589                         goto error;
1590                 return put_u64(seq, arg);
1591         }
1592         case LTTNG_RING_BUFFER_INSTANCE_ID:
1593         {
1594                 uint64_t id;
1595
1596                 ret = ops->instance_id(config, buf, &id);
1597                 if (ret < 0)
1598                         goto error;
1599                 return put_u64(id, arg);
1600         }
1601         default:
1602                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1603                                 cmd, arg);
1604         }
1605
1606 error:
1607         return -ENOSYS;
1608 }
1609
1610 #ifdef CONFIG_COMPAT
1611 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1612                 unsigned int cmd, unsigned long arg)
1613 {
1614         struct lib_ring_buffer *buf = filp->private_data;
1615         struct channel *chan = buf->backend.chan;
1616         const struct lib_ring_buffer_config *config = &chan->backend.config;
1617         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1618         int ret;
1619
1620         if (atomic_read(&chan->record_disabled))
1621                 return -EIO;
1622
1623         switch (cmd) {
1624         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1625         {
1626                 uint64_t ts;
1627
1628                 ret = ops->timestamp_begin(config, buf, &ts);
1629                 if (ret < 0)
1630                         goto error;
1631                 return put_u64(ts, arg);
1632         }
1633         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1634         {
1635                 uint64_t ts;
1636
1637                 ret = ops->timestamp_end(config, buf, &ts);
1638                 if (ret < 0)
1639                         goto error;
1640                 return put_u64(ts, arg);
1641         }
1642         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1643         {
1644                 uint64_t ed;
1645
1646                 ret = ops->events_discarded(config, buf, &ed);
1647                 if (ret < 0)
1648                         goto error;
1649                 return put_u64(ed, arg);
1650         }
1651         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1652         {
1653                 uint64_t cs;
1654
1655                 ret = ops->content_size(config, buf, &cs);
1656                 if (ret < 0)
1657                         goto error;
1658                 return put_u64(cs, arg);
1659         }
1660         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1661         {
1662                 uint64_t ps;
1663
1664                 ret = ops->packet_size(config, buf, &ps);
1665                 if (ret < 0)
1666                         goto error;
1667                 return put_u64(ps, arg);
1668         }
1669         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1670         {
1671                 uint64_t si;
1672
1673                 ret = ops->stream_id(config, buf, &si);
1674                 if (ret < 0)
1675                         goto error;
1676                 return put_u64(si, arg);
1677         }
1678         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1679         {
1680                 uint64_t ts;
1681
1682                 ret = ops->current_timestamp(config, buf, &ts);
1683                 if (ret < 0)
1684                         goto error;
1685                 return put_u64(ts, arg);
1686         }
1687         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1688         {
1689                 uint64_t seq;
1690
1691                 ret = ops->sequence_number(config, buf, &seq);
1692                 if (ret < 0)
1693                         goto error;
1694                 return put_u64(seq, arg);
1695         }
1696         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1697         {
1698                 uint64_t id;
1699
1700                 ret = ops->instance_id(config, buf, &id);
1701                 if (ret < 0)
1702                         goto error;
1703                 return put_u64(id, arg);
1704         }
1705         default:
1706                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1707                                 cmd, arg);
1708         }
1709
1710 error:
1711         return -ENOSYS;
1712 }
1713 #endif /* CONFIG_COMPAT */
1714
1715 static void lttng_stream_override_ring_buffer_fops(void)
1716 {
1717         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1718         lttng_stream_ring_buffer_file_operations.open =
1719                 lib_ring_buffer_file_operations.open;
1720         lttng_stream_ring_buffer_file_operations.release =
1721                 lib_ring_buffer_file_operations.release;
1722         lttng_stream_ring_buffer_file_operations.poll =
1723                 lib_ring_buffer_file_operations.poll;
1724         lttng_stream_ring_buffer_file_operations.splice_read =
1725                 lib_ring_buffer_file_operations.splice_read;
1726         lttng_stream_ring_buffer_file_operations.mmap =
1727                 lib_ring_buffer_file_operations.mmap;
1728         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1729                 lttng_stream_ring_buffer_ioctl;
1730         lttng_stream_ring_buffer_file_operations.llseek =
1731                 lib_ring_buffer_file_operations.llseek;
1732 #ifdef CONFIG_COMPAT
1733         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1734                 lttng_stream_ring_buffer_compat_ioctl;
1735 #endif
1736 }
1737
1738 int __init lttng_abi_init(void)
1739 {
1740         int ret = 0;
1741
1742         wrapper_vmalloc_sync_all();
1743         lttng_clock_ref();
1744         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1745                                         &lttng_fops, NULL);
1746
1747         if (!lttng_proc_dentry) {
1748                 printk(KERN_ERR "Error creating LTTng control file\n");
1749                 ret = -ENOMEM;
1750                 goto error;
1751         }
1752         lttng_stream_override_ring_buffer_fops();
1753         return 0;
1754
1755 error:
1756         lttng_clock_unref();
1757         return ret;
1758 }
1759
1760 /* No __exit annotation because used by init error path too. */
1761 void lttng_abi_exit(void)
1762 {
1763         lttng_clock_unref();
1764         if (lttng_proc_dentry)
1765                 remove_proc_entry("lttng", NULL);
1766 }