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_EMPTY:   /* Fall-through. */
 687         case RING_BUFFER_FLUSH:
 688         {
 689                 struct lttng_metadata_stream *stream = filp->private_data;
 690                 struct lib_ring_buffer *buf = stream->priv;
 691                 struct channel *chan = buf->backend.chan;
 692
 693                 /*
 694                  * Before doing the actual ring buffer flush, write up to one
 695                  * packet of metadata in the ring buffer.
 696                  */
 697                 ret = lttng_metadata_output_channel(stream, chan);
 698                 if (ret < 0)
 699                         goto err;
 700                 break;
 701         }
 702         case RING_BUFFER_GET_METADATA_VERSION:
 703         {
 704                 struct lttng_metadata_stream *stream = filp->private_data;
 705
 706                 return put_u64(stream->version, arg);
 707         }
 708         default:
 709                 break;
 710         }
 711         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 712
 713         /* Performing lib ring buffer ioctl after our own. */
 714         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 715         if (ret < 0)
 716                 goto err;
 717
 718         switch (cmd) {
 719         case RING_BUFFER_PUT_NEXT_SUBBUF:
 720         {
 721                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 722                                 cmd, arg);
 723                 break;
 724         }
 725         default:
 726                 break;
 727         }
 728 err:
 729         return ret;
 730 }
 731
 732 #ifdef CONFIG_COMPAT
 733 static
 734 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 735                 unsigned int cmd, unsigned long arg)
 736 {
 737         int ret;
 738         struct lttng_metadata_stream *stream = filp->private_data;
 739         struct lib_ring_buffer *buf = stream->priv;
 740
 741         switch (cmd) {
 742         case RING_BUFFER_GET_NEXT_SUBBUF:
 743         {
 744                 struct lttng_metadata_stream *stream = filp->private_data;
 745                 struct lib_ring_buffer *buf = stream->priv;
 746                 struct channel *chan = buf->backend.chan;
 747
 748                 ret = lttng_metadata_output_channel(stream, chan);
 749                 if (ret > 0) {
 750                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 751                         ret = 0;
 752                 } else if (ret < 0)
 753                         goto err;
 754                 break;
 755         }
 756         case RING_BUFFER_GET_SUBBUF:
 757         {
 758                 /*
 759                  * Random access is not allowed for metadata channel.
 760                  */
 761                 return -ENOSYS;
 762         }
 763         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 764         case RING_BUFFER_FLUSH:
 765         {
 766                 struct lttng_metadata_stream *stream = filp->private_data;
 767                 struct lib_ring_buffer *buf = stream->priv;
 768                 struct channel *chan = buf->backend.chan;
 769
 770                 /*
 771                  * Before doing the actual ring buffer flush, write up to one
 772                  * packet of metadata in the ring buffer.
 773                  */
 774                 ret = lttng_metadata_output_channel(stream, chan);
 775                 if (ret < 0)
 776                         goto err;
 777                 break;
 778         }
 779         case RING_BUFFER_GET_METADATA_VERSION:
 780         {
 781                 struct lttng_metadata_stream *stream = filp->private_data;
 782
 783                 return put_u64(stream->version, arg);
 784         }
 785         default:
 786                 break;
 787         }
 788         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 789
 790         /* Performing lib ring buffer ioctl after our own. */
 791         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 792         if (ret < 0)
 793                 goto err;
 794
 795         switch (cmd) {
 796         case RING_BUFFER_PUT_NEXT_SUBBUF:
 797         {
 798                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 799                                 cmd, arg);
 800                 break;
 801         }
 802         default:
 803                 break;
 804         }
 805 err:
 806         return ret;
 807 }
 808 #endif
 809
 810 /*
 811  * This is not used by anonymous file descriptors. This code is left
 812  * there if we ever want to implement an inode with open() operation.
 813  */
 814 static
 815 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 816 {
 817         struct lttng_metadata_stream *stream = inode->i_private;
 818         struct lib_ring_buffer *buf = stream->priv;
 819
 820         file->private_data = buf;
 821         /*
 822          * Since life-time of metadata cache differs from that of
 823          * session, we need to keep our own reference on the transport.
 824          */
 825         if (!try_module_get(stream->transport->owner)) {
 826                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 827                 return -EBUSY;
 828         }
 829         return lib_ring_buffer_open(inode, file, buf);
 830 }
 831
 832 static
 833 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 834 {
 835         struct lttng_metadata_stream *stream = file->private_data;
 836         struct lib_ring_buffer *buf = stream->priv;
 837
 838         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 839         module_put(stream->transport->owner);
 840         return lib_ring_buffer_release(inode, file, buf);
 841 }
 842
 843 static
 844 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 845                 struct pipe_inode_info *pipe, size_t len,
 846                 unsigned int flags)
 847 {
 848         struct lttng_metadata_stream *stream = in->private_data;
 849         struct lib_ring_buffer *buf = stream->priv;
 850
 851         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 852                         flags, buf);
 853 }
 854
 855 static
 856 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 857                 struct vm_area_struct *vma)
 858 {
 859         struct lttng_metadata_stream *stream = filp->private_data;
 860         struct lib_ring_buffer *buf = stream->priv;
 861
 862         return lib_ring_buffer_mmap(filp, vma, buf);
 863 }
 864
 865 static
 866 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 867         .owner = THIS_MODULE,
 868         .open = lttng_metadata_ring_buffer_open,
 869         .release = lttng_metadata_ring_buffer_release,
 870         .poll = lttng_metadata_ring_buffer_poll,
 871         .splice_read = lttng_metadata_ring_buffer_splice_read,
 872         .mmap = lttng_metadata_ring_buffer_mmap,
 873         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 874         .llseek = vfs_lib_ring_buffer_no_llseek,
 875 #ifdef CONFIG_COMPAT
 876         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 877 #endif
 878 };
 879
 880 static
 881 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 882                 const struct file_operations *fops)
 883 {
 884         int stream_fd, ret;
 885         struct file *stream_file;
 886
 887         stream_fd = lttng_get_unused_fd();
 888         if (stream_fd < 0) {
 889                 ret = stream_fd;
 890                 goto fd_error;
 891         }
 892         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 893                         stream_priv, O_RDWR);
 894         if (IS_ERR(stream_file)) {
 895                 ret = PTR_ERR(stream_file);
 896                 goto file_error;
 897         }
 898         /*
 899          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 900          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 901          * file descriptor, so we set FMODE_PREAD here.
 902          */
 903         stream_file->f_mode |= FMODE_PREAD;
 904         fd_install(stream_fd, stream_file);
 905         /*
 906          * The stream holds a reference to the channel within the generic ring
 907          * buffer library, so no need to hold a refcount on the channel and
 908          * session files here.
 909          */
 910         return stream_fd;
 911
 912 file_error:
 913         put_unused_fd(stream_fd);
 914 fd_error:
 915         return ret;
 916 }
 917
 918 static
 919 int lttng_abi_open_stream(struct file *channel_file)
 920 {
 921         struct lttng_channel *channel = channel_file->private_data;
 922         struct lib_ring_buffer *buf;
 923         int ret;
 924         void *stream_priv;
 925
 926         buf = channel->ops->buffer_read_open(channel->chan);
 927         if (!buf)
 928                 return -ENOENT;
 929
 930         stream_priv = buf;
 931         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 932                         &lttng_stream_ring_buffer_file_operations);
 933         if (ret < 0)
 934                 goto fd_error;
 935
 936         return ret;
 937
 938 fd_error:
 939         channel->ops->buffer_read_close(buf);
 940         return ret;
 941 }
 942
 943 static
 944 int lttng_abi_open_metadata_stream(struct file *channel_file)
 945 {
 946         struct lttng_channel *channel = channel_file->private_data;
 947         struct lttng_session *session = channel->session;
 948         struct lib_ring_buffer *buf;
 949         int ret;
 950         struct lttng_metadata_stream *metadata_stream;
 951         void *stream_priv;
 952
 953         buf = channel->ops->buffer_read_open(channel->chan);
 954         if (!buf)
 955                 return -ENOENT;
 956
 957         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 958                         GFP_KERNEL);
 959         if (!metadata_stream) {
 960                 ret = -ENOMEM;
 961                 goto nomem;
 962         }
 963         metadata_stream->metadata_cache = session->metadata_cache;
 964         init_waitqueue_head(&metadata_stream->read_wait);
 965         metadata_stream->priv = buf;
 966         stream_priv = metadata_stream;
 967         metadata_stream->transport = channel->transport;
 968
 969         /*
 970          * Since life-time of metadata cache differs from that of
 971          * session, we need to keep our own reference on the transport.
 972          */
 973         if (!try_module_get(metadata_stream->transport->owner)) {
 974                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 975                 ret = -EINVAL;
 976                 goto notransport;
 977         }
 978
 979         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
 980                 ret = -EOVERFLOW;
 981                 goto kref_error;
 982         }
 983
 984         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 985                         &lttng_metadata_ring_buffer_file_operations);
 986         if (ret < 0)
 987                 goto fd_error;
 988
 989         list_add(&metadata_stream->list,
 990                 &session->metadata_cache->metadata_stream);
 991         return ret;
 992
 993 fd_error:
 994         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 995 kref_error:
 996         module_put(metadata_stream->transport->owner);
 997 notransport:
 998         kfree(metadata_stream);
 999 nomem:
1000         channel->ops->buffer_read_close(buf);
1001         return ret;
1002 }
1003
1004 static
1005 int lttng_abi_create_event(struct file *channel_file,
1006                            struct lttng_kernel_event *event_param)
1007 {
1008         struct lttng_channel *channel = channel_file->private_data;
1009         int event_fd, ret;
1010         struct file *event_file;
1011         void *priv;
1012
1013         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1014         switch (event_param->instrumentation) {
1015         case LTTNG_KERNEL_KRETPROBE:
1016                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1017                 break;
1018         case LTTNG_KERNEL_KPROBE:
1019                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1020                 break;
1021         case LTTNG_KERNEL_FUNCTION:
1022                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1023                 break;
1024         default:
1025                 break;
1026         }
1027         event_fd = lttng_get_unused_fd();
1028         if (event_fd < 0) {
1029                 ret = event_fd;
1030                 goto fd_error;
1031         }
1032         event_file = anon_inode_getfile("[lttng_event]",
1033                                         &lttng_event_fops,
1034                                         NULL, O_RDWR);
1035         if (IS_ERR(event_file)) {
1036                 ret = PTR_ERR(event_file);
1037                 goto file_error;
1038         }
1039         /* The event holds a reference on the channel */
1040         if (atomic_long_add_unless(&channel_file->f_count,
1041                 1, INT_MAX) == INT_MAX) {
1042                 ret = -EOVERFLOW;
1043                 goto refcount_error;
1044         }
1045         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1046                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1047                 struct lttng_enabler *enabler;
1048
1049                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1050                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1051                                 event_param, channel);
1052                 } else {
1053                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1054                                 event_param, channel);
1055                 }
1056                 priv = enabler;
1057         } else {
1058                 struct lttng_event *event;
1059
1060                 /*
1061                  * We tolerate no failure path after event creation. It
1062                  * will stay invariant for the rest of the session.
1063                  */
1064                 event = lttng_event_create(channel, event_param,
1065                                 NULL, NULL,
1066                                 event_param->instrumentation);
1067                 WARN_ON_ONCE(!event);
1068                 if (IS_ERR(event)) {
1069                         ret = PTR_ERR(event);
1070                         goto event_error;
1071                 }
1072                 priv = event;
1073         }
1074         event_file->private_data = priv;
1075         fd_install(event_fd, event_file);
1076         return event_fd;
1077
1078 event_error:
1079         atomic_long_dec(&channel_file->f_count);
1080 refcount_error:
1081         fput(event_file);
1082 file_error:
1083         put_unused_fd(event_fd);
1084 fd_error:
1085         return ret;
1086 }
1087
1088 /**
1089  *      lttng_channel_ioctl - lttng syscall through ioctl
1090  *
1091  *      @file: the file
1092  *      @cmd: the command
1093  *      @arg: command arg
1094  *
1095  *      This ioctl implements lttng commands:
1096  *      LTTNG_KERNEL_STREAM
1097  *              Returns an event stream file descriptor or failure.
1098  *              (typically, one event stream records events from one CPU)
1099  *      LTTNG_KERNEL_EVENT
1100  *              Returns an event file descriptor or failure.
1101  *      LTTNG_KERNEL_CONTEXT
1102  *              Prepend a context field to each event in the channel
1103  *      LTTNG_KERNEL_ENABLE
1104  *              Enable recording for events in this channel (weak enable)
1105  *      LTTNG_KERNEL_DISABLE
1106  *              Disable recording for events in this channel (strong disable)
1107  *
1108  * Channel and event file descriptors also hold a reference on the session.
1109  */
1110 static
1111 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1112 {
1113         struct lttng_channel *channel = file->private_data;
1114
1115         switch (cmd) {
1116         case LTTNG_KERNEL_OLD_STREAM:
1117         case LTTNG_KERNEL_STREAM:
1118                 return lttng_abi_open_stream(file);
1119         case LTTNG_KERNEL_OLD_EVENT:
1120         {
1121                 struct lttng_kernel_event *uevent_param;
1122                 struct lttng_kernel_old_event *old_uevent_param;
1123                 int ret;
1124
1125                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1126                                 GFP_KERNEL);
1127                 if (!uevent_param) {
1128                         ret = -ENOMEM;
1129                         goto old_event_end;
1130                 }
1131                 old_uevent_param = kmalloc(
1132                                 sizeof(struct lttng_kernel_old_event),
1133                                 GFP_KERNEL);
1134                 if (!old_uevent_param) {
1135                         ret = -ENOMEM;
1136                         goto old_event_error_free_param;
1137                 }
1138                 if (copy_from_user(old_uevent_param,
1139                                 (struct lttng_kernel_old_event __user *) arg,
1140                                 sizeof(struct lttng_kernel_old_event))) {
1141                         ret = -EFAULT;
1142                         goto old_event_error_free_old_param;
1143                 }
1144
1145                 memcpy(uevent_param->name, old_uevent_param->name,
1146                                 sizeof(uevent_param->name));
1147                 uevent_param->instrumentation =
1148                         old_uevent_param->instrumentation;
1149
1150                 switch (old_uevent_param->instrumentation) {
1151                 case LTTNG_KERNEL_KPROBE:
1152                         uevent_param->u.kprobe.addr =
1153                                 old_uevent_param->u.kprobe.addr;
1154                         uevent_param->u.kprobe.offset =
1155                                 old_uevent_param->u.kprobe.offset;
1156                         memcpy(uevent_param->u.kprobe.symbol_name,
1157                                 old_uevent_param->u.kprobe.symbol_name,
1158                                 sizeof(uevent_param->u.kprobe.symbol_name));
1159                         break;
1160                 case LTTNG_KERNEL_KRETPROBE:
1161                         uevent_param->u.kretprobe.addr =
1162                                 old_uevent_param->u.kretprobe.addr;
1163                         uevent_param->u.kretprobe.offset =
1164                                 old_uevent_param->u.kretprobe.offset;
1165                         memcpy(uevent_param->u.kretprobe.symbol_name,
1166                                 old_uevent_param->u.kretprobe.symbol_name,
1167                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1168                         break;
1169                 case LTTNG_KERNEL_FUNCTION:
1170                         memcpy(uevent_param->u.ftrace.symbol_name,
1171                                         old_uevent_param->u.ftrace.symbol_name,
1172                                         sizeof(uevent_param->u.ftrace.symbol_name));
1173                         break;
1174                 default:
1175                         break;
1176                 }
1177                 ret = lttng_abi_create_event(file, uevent_param);
1178
1179 old_event_error_free_old_param:
1180                 kfree(old_uevent_param);
1181 old_event_error_free_param:
1182                 kfree(uevent_param);
1183 old_event_end:
1184                 return ret;
1185         }
1186         case LTTNG_KERNEL_EVENT:
1187         {
1188                 struct lttng_kernel_event uevent_param;
1189
1190                 if (copy_from_user(&uevent_param,
1191                                 (struct lttng_kernel_event __user *) arg,
1192                                 sizeof(uevent_param)))
1193                         return -EFAULT;
1194                 return lttng_abi_create_event(file, &uevent_param);
1195         }
1196         case LTTNG_KERNEL_OLD_CONTEXT:
1197         {
1198                 struct lttng_kernel_context *ucontext_param;
1199                 struct lttng_kernel_old_context *old_ucontext_param;
1200                 int ret;
1201
1202                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1203                                 GFP_KERNEL);
1204                 if (!ucontext_param) {
1205                         ret = -ENOMEM;
1206                         goto old_ctx_end;
1207                 }
1208                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1209                                 GFP_KERNEL);
1210                 if (!old_ucontext_param) {
1211                         ret = -ENOMEM;
1212                         goto old_ctx_error_free_param;
1213                 }
1214
1215                 if (copy_from_user(old_ucontext_param,
1216                                 (struct lttng_kernel_old_context __user *) arg,
1217                                 sizeof(struct lttng_kernel_old_context))) {
1218                         ret = -EFAULT;
1219                         goto old_ctx_error_free_old_param;
1220                 }
1221                 ucontext_param->ctx = old_ucontext_param->ctx;
1222                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1223                                 sizeof(ucontext_param->padding));
1224                 /* only type that uses the union */
1225                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1226                         ucontext_param->u.perf_counter.type =
1227                                 old_ucontext_param->u.perf_counter.type;
1228                         ucontext_param->u.perf_counter.config =
1229                                 old_ucontext_param->u.perf_counter.config;
1230                         memcpy(ucontext_param->u.perf_counter.name,
1231                                 old_ucontext_param->u.perf_counter.name,
1232                                 sizeof(ucontext_param->u.perf_counter.name));
1233                 }
1234
1235                 ret = lttng_abi_add_context(file,
1236                                 ucontext_param,
1237                                 &channel->ctx, channel->session);
1238
1239 old_ctx_error_free_old_param:
1240                 kfree(old_ucontext_param);
1241 old_ctx_error_free_param:
1242                 kfree(ucontext_param);
1243 old_ctx_end:
1244                 return ret;
1245         }
1246         case LTTNG_KERNEL_CONTEXT:
1247         {
1248                 struct lttng_kernel_context ucontext_param;
1249
1250                 if (copy_from_user(&ucontext_param,
1251                                 (struct lttng_kernel_context __user *) arg,
1252                                 sizeof(ucontext_param)))
1253                         return -EFAULT;
1254                 return lttng_abi_add_context(file,
1255                                 &ucontext_param,
1256                                 &channel->ctx, channel->session);
1257         }
1258         case LTTNG_KERNEL_OLD_ENABLE:
1259         case LTTNG_KERNEL_ENABLE:
1260                 return lttng_channel_enable(channel);
1261         case LTTNG_KERNEL_OLD_DISABLE:
1262         case LTTNG_KERNEL_DISABLE:
1263                 return lttng_channel_disable(channel);
1264         case LTTNG_KERNEL_SYSCALL_MASK:
1265                 return lttng_channel_syscall_mask(channel,
1266                         (struct lttng_kernel_syscall_mask __user *) arg);
1267         default:
1268                 return -ENOIOCTLCMD;
1269         }
1270
1271 }
1272
1273 /**
1274  *      lttng_metadata_ioctl - lttng syscall through ioctl
1275  *
1276  *      @file: the file
1277  *      @cmd: the command
1278  *      @arg: command arg
1279  *
1280  *      This ioctl implements lttng commands:
1281  *      LTTNG_KERNEL_STREAM
1282  *              Returns an event stream file descriptor or failure.
1283  *
1284  * Channel and event file descriptors also hold a reference on the session.
1285  */
1286 static
1287 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1288 {
1289         switch (cmd) {
1290         case LTTNG_KERNEL_OLD_STREAM:
1291         case LTTNG_KERNEL_STREAM:
1292                 return lttng_abi_open_metadata_stream(file);
1293         default:
1294                 return -ENOIOCTLCMD;
1295         }
1296 }
1297
1298 /**
1299  *      lttng_channel_poll - lttng stream addition/removal monitoring
1300  *
1301  *      @file: the file
1302  *      @wait: poll table
1303  */
1304 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1305 {
1306         struct lttng_channel *channel = file->private_data;
1307         unsigned int mask = 0;
1308
1309         if (file->f_mode & FMODE_READ) {
1310                 poll_wait_set_exclusive(wait);
1311                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1312                           wait);
1313
1314                 if (channel->ops->is_disabled(channel->chan))
1315                         return POLLERR;
1316                 if (channel->ops->is_finalized(channel->chan))
1317                         return POLLHUP;
1318                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1319                         return POLLIN | POLLRDNORM;
1320                 return 0;
1321         }
1322         return mask;
1323
1324 }
1325
1326 static
1327 int lttng_channel_release(struct inode *inode, struct file *file)
1328 {
1329         struct lttng_channel *channel = file->private_data;
1330
1331         if (channel)
1332                 fput(channel->session->file);
1333         return 0;
1334 }
1335
1336 static
1337 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1338 {
1339         struct lttng_channel *channel = file->private_data;
1340
1341         if (channel) {
1342                 fput(channel->session->file);
1343                 lttng_metadata_channel_destroy(channel);
1344         }
1345
1346         return 0;
1347 }
1348
1349 static const struct file_operations lttng_channel_fops = {
1350         .owner = THIS_MODULE,
1351         .release = lttng_channel_release,
1352         .poll = lttng_channel_poll,
1353         .unlocked_ioctl = lttng_channel_ioctl,
1354 #ifdef CONFIG_COMPAT
1355         .compat_ioctl = lttng_channel_ioctl,
1356 #endif
1357 };
1358
1359 static const struct file_operations lttng_metadata_fops = {
1360         .owner = THIS_MODULE,
1361         .release = lttng_metadata_channel_release,
1362         .unlocked_ioctl = lttng_metadata_ioctl,
1363 #ifdef CONFIG_COMPAT
1364         .compat_ioctl = lttng_metadata_ioctl,
1365 #endif
1366 };
1367
1368 /**
1369  *      lttng_event_ioctl - lttng syscall through ioctl
1370  *
1371  *      @file: the file
1372  *      @cmd: the command
1373  *      @arg: command arg
1374  *
1375  *      This ioctl implements lttng commands:
1376  *      LTTNG_KERNEL_CONTEXT
1377  *              Prepend a context field to each record of this event
1378  *      LTTNG_KERNEL_ENABLE
1379  *              Enable recording for this event (weak enable)
1380  *      LTTNG_KERNEL_DISABLE
1381  *              Disable recording for this event (strong disable)
1382  */
1383 static
1384 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1385 {
1386         struct lttng_event *event;
1387         struct lttng_enabler *enabler;
1388         enum lttng_event_type *evtype = file->private_data;
1389
1390         switch (cmd) {
1391         case LTTNG_KERNEL_OLD_CONTEXT:
1392         {
1393                 /* Not implemented */
1394                 return -ENOSYS;
1395         }
1396         case LTTNG_KERNEL_CONTEXT:
1397         {
1398                 /* Not implemented */
1399                 return -ENOSYS;
1400         }
1401         case LTTNG_KERNEL_OLD_ENABLE:
1402         case LTTNG_KERNEL_ENABLE:
1403                 switch (*evtype) {
1404                 case LTTNG_TYPE_EVENT:
1405                         event = file->private_data;
1406                         return lttng_event_enable(event);
1407                 case LTTNG_TYPE_ENABLER:
1408                         enabler = file->private_data;
1409                         return lttng_enabler_enable(enabler);
1410                 default:
1411                         WARN_ON_ONCE(1);
1412                         return -ENOSYS;
1413                 }
1414         case LTTNG_KERNEL_OLD_DISABLE:
1415         case LTTNG_KERNEL_DISABLE:
1416                 switch (*evtype) {
1417                 case LTTNG_TYPE_EVENT:
1418                         event = file->private_data;
1419                         return lttng_event_disable(event);
1420                 case LTTNG_TYPE_ENABLER:
1421                         enabler = file->private_data;
1422                         return lttng_enabler_disable(enabler);
1423                 default:
1424                         WARN_ON_ONCE(1);
1425                         return -ENOSYS;
1426                 }
1427         case LTTNG_KERNEL_FILTER:
1428                 switch (*evtype) {
1429                 case LTTNG_TYPE_EVENT:
1430                         return -EINVAL;
1431                 case LTTNG_TYPE_ENABLER:
1432                 {
1433                         enabler = file->private_data;
1434                         return lttng_enabler_attach_bytecode(enabler,
1435                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1436                 }
1437
1438                 }
1439         default:
1440                 return -ENOIOCTLCMD;
1441         }
1442 }
1443
1444 static
1445 int lttng_event_release(struct inode *inode, struct file *file)
1446 {
1447         struct lttng_event *event;
1448         struct lttng_enabler *enabler;
1449         enum lttng_event_type *evtype = file->private_data;
1450
1451         if (!evtype)
1452                 return 0;
1453
1454         switch (*evtype) {
1455         case LTTNG_TYPE_EVENT:
1456                 event = file->private_data;
1457                 if (event)
1458                         fput(event->chan->file);
1459                 break;
1460         case LTTNG_TYPE_ENABLER:
1461                 enabler = file->private_data;
1462                 if (enabler)
1463                         fput(enabler->chan->file);
1464                 break;
1465         default:
1466                 WARN_ON_ONCE(1);
1467                 break;
1468         }
1469
1470         return 0;
1471 }
1472
1473 /* TODO: filter control ioctl */
1474 static const struct file_operations lttng_event_fops = {
1475         .owner = THIS_MODULE,
1476         .release = lttng_event_release,
1477         .unlocked_ioctl = lttng_event_ioctl,
1478 #ifdef CONFIG_COMPAT
1479         .compat_ioctl = lttng_event_ioctl,
1480 #endif
1481 };
1482
1483 static int put_u64(uint64_t val, unsigned long arg)
1484 {
1485         return put_user(val, (uint64_t __user *) arg);
1486 }
1487
1488 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1489                 unsigned int cmd, unsigned long arg)
1490 {
1491         struct lib_ring_buffer *buf = filp->private_data;
1492         struct channel *chan = buf->backend.chan;
1493         const struct lib_ring_buffer_config *config = &chan->backend.config;
1494         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1495         int ret;
1496
1497         if (atomic_read(&chan->record_disabled))
1498                 return -EIO;
1499
1500         switch (cmd) {
1501         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1502         {
1503                 uint64_t ts;
1504
1505                 ret = ops->timestamp_begin(config, buf, &ts);
1506                 if (ret < 0)
1507                         goto error;
1508                 return put_u64(ts, arg);
1509         }
1510         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1511         {
1512                 uint64_t ts;
1513
1514                 ret = ops->timestamp_end(config, buf, &ts);
1515                 if (ret < 0)
1516                         goto error;
1517                 return put_u64(ts, arg);
1518         }
1519         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1520         {
1521                 uint64_t ed;
1522
1523                 ret = ops->events_discarded(config, buf, &ed);
1524                 if (ret < 0)
1525                         goto error;
1526                 return put_u64(ed, arg);
1527         }
1528         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1529         {
1530                 uint64_t cs;
1531
1532                 ret = ops->content_size(config, buf, &cs);
1533                 if (ret < 0)
1534                         goto error;
1535                 return put_u64(cs, arg);
1536         }
1537         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1538         {
1539                 uint64_t ps;
1540
1541                 ret = ops->packet_size(config, buf, &ps);
1542                 if (ret < 0)
1543                         goto error;
1544                 return put_u64(ps, arg);
1545         }
1546         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1547         {
1548                 uint64_t si;
1549
1550                 ret = ops->stream_id(config, buf, &si);
1551                 if (ret < 0)
1552                         goto error;
1553                 return put_u64(si, arg);
1554         }
1555         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1556         {
1557                 uint64_t ts;
1558
1559                 ret = ops->current_timestamp(config, buf, &ts);
1560                 if (ret < 0)
1561                         goto error;
1562                 return put_u64(ts, arg);
1563         }
1564         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1565         {
1566                 uint64_t seq;
1567
1568                 ret = ops->sequence_number(config, buf, &seq);
1569                 if (ret < 0)
1570                         goto error;
1571                 return put_u64(seq, arg);
1572         }
1573         case LTTNG_RING_BUFFER_INSTANCE_ID:
1574         {
1575                 uint64_t id;
1576
1577                 ret = ops->instance_id(config, buf, &id);
1578                 if (ret < 0)
1579                         goto error;
1580                 return put_u64(id, arg);
1581         }
1582         default:
1583                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1584                                 cmd, arg);
1585         }
1586
1587 error:
1588         return -ENOSYS;
1589 }
1590
1591 #ifdef CONFIG_COMPAT
1592 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1593                 unsigned int cmd, unsigned long arg)
1594 {
1595         struct lib_ring_buffer *buf = filp->private_data;
1596         struct channel *chan = buf->backend.chan;
1597         const struct lib_ring_buffer_config *config = &chan->backend.config;
1598         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1599         int ret;
1600
1601         if (atomic_read(&chan->record_disabled))
1602                 return -EIO;
1603
1604         switch (cmd) {
1605         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1606         {
1607                 uint64_t ts;
1608
1609                 ret = ops->timestamp_begin(config, buf, &ts);
1610                 if (ret < 0)
1611                         goto error;
1612                 return put_u64(ts, arg);
1613         }
1614         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1615         {
1616                 uint64_t ts;
1617
1618                 ret = ops->timestamp_end(config, buf, &ts);
1619                 if (ret < 0)
1620                         goto error;
1621                 return put_u64(ts, arg);
1622         }
1623         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1624         {
1625                 uint64_t ed;
1626
1627                 ret = ops->events_discarded(config, buf, &ed);
1628                 if (ret < 0)
1629                         goto error;
1630                 return put_u64(ed, arg);
1631         }
1632         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1633         {
1634                 uint64_t cs;
1635
1636                 ret = ops->content_size(config, buf, &cs);
1637                 if (ret < 0)
1638                         goto error;
1639                 return put_u64(cs, arg);
1640         }
1641         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1642         {
1643                 uint64_t ps;
1644
1645                 ret = ops->packet_size(config, buf, &ps);
1646                 if (ret < 0)
1647                         goto error;
1648                 return put_u64(ps, arg);
1649         }
1650         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1651         {
1652                 uint64_t si;
1653
1654                 ret = ops->stream_id(config, buf, &si);
1655                 if (ret < 0)
1656                         goto error;
1657                 return put_u64(si, arg);
1658         }
1659         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1660         {
1661                 uint64_t ts;
1662
1663                 ret = ops->current_timestamp(config, buf, &ts);
1664                 if (ret < 0)
1665                         goto error;
1666                 return put_u64(ts, arg);
1667         }
1668         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1669         {
1670                 uint64_t seq;
1671
1672                 ret = ops->sequence_number(config, buf, &seq);
1673                 if (ret < 0)
1674                         goto error;
1675                 return put_u64(seq, arg);
1676         }
1677         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1678         {
1679                 uint64_t id;
1680
1681                 ret = ops->instance_id(config, buf, &id);
1682                 if (ret < 0)
1683                         goto error;
1684                 return put_u64(id, arg);
1685         }
1686         default:
1687                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1688                                 cmd, arg);
1689         }
1690
1691 error:
1692         return -ENOSYS;
1693 }
1694 #endif /* CONFIG_COMPAT */
1695
1696 static void lttng_stream_override_ring_buffer_fops(void)
1697 {
1698         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1699         lttng_stream_ring_buffer_file_operations.open =
1700                 lib_ring_buffer_file_operations.open;
1701         lttng_stream_ring_buffer_file_operations.release =
1702                 lib_ring_buffer_file_operations.release;
1703         lttng_stream_ring_buffer_file_operations.poll =
1704                 lib_ring_buffer_file_operations.poll;
1705         lttng_stream_ring_buffer_file_operations.splice_read =
1706                 lib_ring_buffer_file_operations.splice_read;
1707         lttng_stream_ring_buffer_file_operations.mmap =
1708                 lib_ring_buffer_file_operations.mmap;
1709         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1710                 lttng_stream_ring_buffer_ioctl;
1711         lttng_stream_ring_buffer_file_operations.llseek =
1712                 lib_ring_buffer_file_operations.llseek;
1713 #ifdef CONFIG_COMPAT
1714         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1715                 lttng_stream_ring_buffer_compat_ioctl;
1716 #endif
1717 }
1718
1719 int __init lttng_abi_init(void)
1720 {
1721         int ret = 0;
1722
1723         wrapper_vmalloc_sync_all();
1724         lttng_clock_ref();
1725         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1726                                         &lttng_fops, NULL);
1727
1728         if (!lttng_proc_dentry) {
1729                 printk(KERN_ERR "Error creating LTTng control file\n");
1730                 ret = -ENOMEM;
1731                 goto error;
1732         }
1733         lttng_stream_override_ring_buffer_fops();
1734         return 0;
1735
1736 error:
1737         lttng_clock_unref();
1738         return ret;
1739 }
1740
1741 /* No __exit annotation because used by init error path too. */
1742 void lttng_abi_exit(void)
1743 {
1744         lttng_clock_unref();
1745         if (lttng_proc_dentry)
1746                 remove_proc_entry("lttng", NULL);
1747 }