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