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-string-utils.h>
  55 #include <lttng-abi.h>
  56 #include <lttng-abi-old.h>
  57 #include <lttng-events.h>
  58 #include <lttng-tracer.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,
 433                 1, INT_MAX) == INT_MAX) {
 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
 494         switch (cmd) {
 495         case LTTNG_KERNEL_OLD_CHANNEL:
 496         {
 497                 struct lttng_kernel_channel chan_param;
 498                 struct lttng_kernel_old_channel old_chan_param;
 499
 500                 if (copy_from_user(&old_chan_param,
 501                                 (struct lttng_kernel_old_channel __user *) arg,
 502                                 sizeof(struct lttng_kernel_old_channel)))
 503                         return -EFAULT;
 504                 chan_param.overwrite = old_chan_param.overwrite;
 505                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 506                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 507                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 508                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 509                 chan_param.output = old_chan_param.output;
 510
 511                 return lttng_abi_create_channel(file, &chan_param,
 512                                 PER_CPU_CHANNEL);
 513         }
 514         case LTTNG_KERNEL_CHANNEL:
 515         {
 516                 struct lttng_kernel_channel chan_param;
 517
 518                 if (copy_from_user(&chan_param,
 519                                 (struct lttng_kernel_channel __user *) arg,
 520                                 sizeof(struct lttng_kernel_channel)))
 521                         return -EFAULT;
 522                 return lttng_abi_create_channel(file, &chan_param,
 523                                 PER_CPU_CHANNEL);
 524         }
 525         case LTTNG_KERNEL_OLD_SESSION_START:
 526         case LTTNG_KERNEL_OLD_ENABLE:
 527         case LTTNG_KERNEL_SESSION_START:
 528         case LTTNG_KERNEL_ENABLE:
 529                 return lttng_session_enable(session);
 530         case LTTNG_KERNEL_OLD_SESSION_STOP:
 531         case LTTNG_KERNEL_OLD_DISABLE:
 532         case LTTNG_KERNEL_SESSION_STOP:
 533         case LTTNG_KERNEL_DISABLE:
 534                 return lttng_session_disable(session);
 535         case LTTNG_KERNEL_OLD_METADATA:
 536         {
 537                 struct lttng_kernel_channel chan_param;
 538                 struct lttng_kernel_old_channel old_chan_param;
 539
 540                 if (copy_from_user(&old_chan_param,
 541                                 (struct lttng_kernel_old_channel __user *) arg,
 542                                 sizeof(struct lttng_kernel_old_channel)))
 543                         return -EFAULT;
 544                 chan_param.overwrite = old_chan_param.overwrite;
 545                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 546                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 547                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 548                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 549                 chan_param.output = old_chan_param.output;
 550
 551                 return lttng_abi_create_channel(file, &chan_param,
 552                                 METADATA_CHANNEL);
 553         }
 554         case LTTNG_KERNEL_METADATA:
 555         {
 556                 struct lttng_kernel_channel chan_param;
 557
 558                 if (copy_from_user(&chan_param,
 559                                         (struct lttng_kernel_channel __user *) arg,
 560                                         sizeof(struct lttng_kernel_channel)))
 561                         return -EFAULT;
 562                 return lttng_abi_create_channel(file, &chan_param,
 563                                 METADATA_CHANNEL);
 564         }
 565         case LTTNG_KERNEL_SESSION_TRACK_PID:
 566                 return lttng_session_track_pid(session, (int) arg);
 567         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 568                 return lttng_session_untrack_pid(session, (int) arg);
 569         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 570                 return lttng_session_list_tracker_pids(session);
 571         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 572                 return lttng_session_metadata_regenerate(session);
 573         case LTTNG_KERNEL_SESSION_STATEDUMP:
 574                 return lttng_session_statedump(session);
 575         default:
 576                 return -ENOIOCTLCMD;
 577         }
 578 }
 579
 580 /*
 581  * Called when the last file reference is dropped.
 582  *
 583  * Big fat note: channels and events are invariant for the whole session after
 584  * their creation. So this session destruction also destroys all channel and
 585  * event structures specific to this session (they are not destroyed when their
 586  * individual file is released).
 587  */
 588 static
 589 int lttng_session_release(struct inode *inode, struct file *file)
 590 {
 591         struct lttng_session *session = file->private_data;
 592
 593         if (session)
 594                 lttng_session_destroy(session);
 595         return 0;
 596 }
 597
 598 static const struct file_operations lttng_session_fops = {
 599         .owner = THIS_MODULE,
 600         .release = lttng_session_release,
 601         .unlocked_ioctl = lttng_session_ioctl,
 602 #ifdef CONFIG_COMPAT
 603         .compat_ioctl = lttng_session_ioctl,
 604 #endif
 605 };
 606
 607 /**
 608  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 609  *      @filp: the file
 610  *      @wait: poll table
 611  *
 612  *      Handles the poll operations for the metadata channels.
 613  */
 614 static
 615 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 616                 poll_table *wait)
 617 {
 618         struct lttng_metadata_stream *stream = filp->private_data;
 619         struct lib_ring_buffer *buf = stream->priv;
 620         int finalized;
 621         unsigned int mask = 0;
 622
 623         if (filp->f_mode & FMODE_READ) {
 624                 poll_wait_set_exclusive(wait);
 625                 poll_wait(filp, &stream->read_wait, wait);
 626
 627                 finalized = stream->finalized;
 628
 629                 /*
 630                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 631                  * ordering finalized load before offsets loads.
 632                  */
 633                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 634
 635                 if (finalized)
 636                         mask |= POLLHUP;
 637
 638                 mutex_lock(&stream->metadata_cache->lock);
 639                 if (stream->metadata_cache->metadata_written >
 640                                 stream->metadata_out)
 641                         mask |= POLLIN;
 642                 mutex_unlock(&stream->metadata_cache->lock);
 643         }
 644
 645         return mask;
 646 }
 647
 648 static
 649 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 650                 unsigned int cmd, unsigned long arg)
 651 {
 652         struct lttng_metadata_stream *stream = filp->private_data;
 653
 654         stream->metadata_out = stream->metadata_in;
 655 }
 656
 657 static
 658 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 659                 unsigned int cmd, unsigned long arg)
 660 {
 661         int ret;
 662         struct lttng_metadata_stream *stream = filp->private_data;
 663         struct lib_ring_buffer *buf = stream->priv;
 664
 665         switch (cmd) {
 666         case RING_BUFFER_GET_NEXT_SUBBUF:
 667         {
 668                 struct lttng_metadata_stream *stream = filp->private_data;
 669                 struct lib_ring_buffer *buf = stream->priv;
 670                 struct channel *chan = buf->backend.chan;
 671
 672                 ret = lttng_metadata_output_channel(stream, chan);
 673                 if (ret > 0) {
 674                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 675                         ret = 0;
 676                 } else if (ret < 0)
 677                         goto err;
 678                 break;
 679         }
 680         case RING_BUFFER_GET_SUBBUF:
 681         {
 682                 /*
 683                  * Random access is not allowed for metadata channel.
 684                  */
 685                 return -ENOSYS;
 686         }
 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         case RING_BUFFER_SNAPSHOT:
 709         {
 710                 /*
 711                  * Force the buffer to quiescent so the ring buffer
 712                  * don't attempt to perform a SWITCH_FLUSH, which would
 713                  * desynchronize the client accounting of the amount of
 714                  * data available in the buffer from the ring buffer
 715                  * view.
 716                  */
 717                 buf->quiescent = true;
 718                 break;
 719         }
 720         default:
 721                 break;
 722         }
 723         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 724
 725         /* Performing lib ring buffer ioctl after our own. */
 726         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 727         if (ret < 0)
 728                 goto err;
 729
 730         switch (cmd) {
 731         case RING_BUFFER_PUT_NEXT_SUBBUF:
 732         {
 733                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 734                                 cmd, arg);
 735                 break;
 736         }
 737         default:
 738                 break;
 739         }
 740 err:
 741         return ret;
 742 }
 743
 744 #ifdef CONFIG_COMPAT
 745 static
 746 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 747                 unsigned int cmd, unsigned long arg)
 748 {
 749         int ret;
 750         struct lttng_metadata_stream *stream = filp->private_data;
 751         struct lib_ring_buffer *buf = stream->priv;
 752
 753         switch (cmd) {
 754         case RING_BUFFER_GET_NEXT_SUBBUF:
 755         {
 756                 struct lttng_metadata_stream *stream = filp->private_data;
 757                 struct lib_ring_buffer *buf = stream->priv;
 758                 struct channel *chan = buf->backend.chan;
 759
 760                 ret = lttng_metadata_output_channel(stream, chan);
 761                 if (ret > 0) {
 762                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 763                         ret = 0;
 764                 } else if (ret < 0)
 765                         goto err;
 766                 break;
 767         }
 768         case RING_BUFFER_GET_SUBBUF:
 769         {
 770                 /*
 771                  * Random access is not allowed for metadata channel.
 772                  */
 773                 return -ENOSYS;
 774         }
 775         case RING_BUFFER_FLUSH:
 776         {
 777                 struct lttng_metadata_stream *stream = filp->private_data;
 778                 struct lib_ring_buffer *buf = stream->priv;
 779                 struct channel *chan = buf->backend.chan;
 780
 781                 /*
 782                  * Before doing the actual ring buffer flush, write up to one
 783                  * packet of metadata in the ring buffer.
 784                  */
 785                 ret = lttng_metadata_output_channel(stream, chan);
 786                 if (ret < 0)
 787                         goto err;
 788                 break;
 789         }
 790         case RING_BUFFER_GET_METADATA_VERSION:
 791         {
 792                 struct lttng_metadata_stream *stream = filp->private_data;
 793
 794                 return put_u64(stream->version, arg);
 795         }
 796         case RING_BUFFER_SNAPSHOT:
 797         {
 798                 /*
 799                  * Force the buffer to quiescent so the ring buffer
 800                  * don't attempt to perform a SWITCH_FLUSH, which would
 801                  * desynchronize the client accounting of the amount of
 802                  * data available in the buffer from the ring buffer
 803                  * view.
 804                  */
 805                 buf->quiescent = true;
 806                 break;
 807         }
 808         default:
 809                 break;
 810         }
 811         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 812
 813         /* Performing lib ring buffer ioctl after our own. */
 814         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 815         if (ret < 0)
 816                 goto err;
 817
 818         switch (cmd) {
 819         case RING_BUFFER_PUT_NEXT_SUBBUF:
 820         {
 821                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 822                                 cmd, arg);
 823                 break;
 824         }
 825         default:
 826                 break;
 827         }
 828 err:
 829         return ret;
 830 }
 831 #endif
 832
 833 /*
 834  * This is not used by anonymous file descriptors. This code is left
 835  * there if we ever want to implement an inode with open() operation.
 836  */
 837 static
 838 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 839 {
 840         struct lttng_metadata_stream *stream = inode->i_private;
 841         struct lib_ring_buffer *buf = stream->priv;
 842
 843         file->private_data = buf;
 844         /*
 845          * Since life-time of metadata cache differs from that of
 846          * session, we need to keep our own reference on the transport.
 847          */
 848         if (!try_module_get(stream->transport->owner)) {
 849                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 850                 return -EBUSY;
 851         }
 852         return lib_ring_buffer_open(inode, file, buf);
 853 }
 854
 855 static
 856 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 857 {
 858         struct lttng_metadata_stream *stream = file->private_data;
 859         struct lib_ring_buffer *buf = stream->priv;
 860
 861         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 862         module_put(stream->transport->owner);
 863         return lib_ring_buffer_release(inode, file, buf);
 864 }
 865
 866 static
 867 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 868                 struct pipe_inode_info *pipe, size_t len,
 869                 unsigned int flags)
 870 {
 871         struct lttng_metadata_stream *stream = in->private_data;
 872         struct lib_ring_buffer *buf = stream->priv;
 873
 874         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 875                         flags, buf);
 876 }
 877
 878 static
 879 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 880                 struct vm_area_struct *vma)
 881 {
 882         struct lttng_metadata_stream *stream = filp->private_data;
 883         struct lib_ring_buffer *buf = stream->priv;
 884
 885         return lib_ring_buffer_mmap(filp, vma, buf);
 886 }
 887
 888 static
 889 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 890         .owner = THIS_MODULE,
 891         .open = lttng_metadata_ring_buffer_open,
 892         .release = lttng_metadata_ring_buffer_release,
 893         .poll = lttng_metadata_ring_buffer_poll,
 894         .splice_read = lttng_metadata_ring_buffer_splice_read,
 895         .mmap = lttng_metadata_ring_buffer_mmap,
 896         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 897         .llseek = vfs_lib_ring_buffer_no_llseek,
 898 #ifdef CONFIG_COMPAT
 899         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 900 #endif
 901 };
 902
 903 static
 904 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 905                 const struct file_operations *fops)
 906 {
 907         int stream_fd, ret;
 908         struct file *stream_file;
 909
 910         stream_fd = lttng_get_unused_fd();
 911         if (stream_fd < 0) {
 912                 ret = stream_fd;
 913                 goto fd_error;
 914         }
 915         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 916                         stream_priv, O_RDWR);
 917         if (IS_ERR(stream_file)) {
 918                 ret = PTR_ERR(stream_file);
 919                 goto file_error;
 920         }
 921         /*
 922          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 923          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 924          * file descriptor, so we set FMODE_PREAD here.
 925          */
 926         stream_file->f_mode |= FMODE_PREAD;
 927         fd_install(stream_fd, stream_file);
 928         /*
 929          * The stream holds a reference to the channel within the generic ring
 930          * buffer library, so no need to hold a refcount on the channel and
 931          * session files here.
 932          */
 933         return stream_fd;
 934
 935 file_error:
 936         put_unused_fd(stream_fd);
 937 fd_error:
 938         return ret;
 939 }
 940
 941 static
 942 int lttng_abi_open_stream(struct file *channel_file)
 943 {
 944         struct lttng_channel *channel = channel_file->private_data;
 945         struct lib_ring_buffer *buf;
 946         int ret;
 947         void *stream_priv;
 948
 949         buf = channel->ops->buffer_read_open(channel->chan);
 950         if (!buf)
 951                 return -ENOENT;
 952
 953         stream_priv = buf;
 954         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 955                         &lttng_stream_ring_buffer_file_operations);
 956         if (ret < 0)
 957                 goto fd_error;
 958
 959         return ret;
 960
 961 fd_error:
 962         channel->ops->buffer_read_close(buf);
 963         return ret;
 964 }
 965
 966 static
 967 int lttng_abi_open_metadata_stream(struct file *channel_file)
 968 {
 969         struct lttng_channel *channel = channel_file->private_data;
 970         struct lttng_session *session = channel->session;
 971         struct lib_ring_buffer *buf;
 972         int ret;
 973         struct lttng_metadata_stream *metadata_stream;
 974         void *stream_priv;
 975
 976         buf = channel->ops->buffer_read_open(channel->chan);
 977         if (!buf)
 978                 return -ENOENT;
 979
 980         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 981                         GFP_KERNEL);
 982         if (!metadata_stream) {
 983                 ret = -ENOMEM;
 984                 goto nomem;
 985         }
 986         metadata_stream->metadata_cache = session->metadata_cache;
 987         init_waitqueue_head(&metadata_stream->read_wait);
 988         metadata_stream->priv = buf;
 989         stream_priv = metadata_stream;
 990         metadata_stream->transport = channel->transport;
 991
 992         /*
 993          * Since life-time of metadata cache differs from that of
 994          * session, we need to keep our own reference on the transport.
 995          */
 996         if (!try_module_get(metadata_stream->transport->owner)) {
 997                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 998                 ret = -EINVAL;
 999                 goto notransport;
1000         }
1001
1002         if (!lttng_kref_get(&session->metadata_cache->refcount))
1003                 goto kref_error;
1004         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1005                         &lttng_metadata_ring_buffer_file_operations);
1006         if (ret < 0)
1007                 goto fd_error;
1008
1009         list_add(&metadata_stream->list,
1010                 &session->metadata_cache->metadata_stream);
1011         return ret;
1012
1013 fd_error:
1014         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1015 kref_error:
1016         module_put(metadata_stream->transport->owner);
1017 notransport:
1018         kfree(metadata_stream);
1019 nomem:
1020         channel->ops->buffer_read_close(buf);
1021         return ret;
1022 }
1023
1024 static
1025 int lttng_abi_create_event(struct file *channel_file,
1026                            struct lttng_kernel_event *event_param)
1027 {
1028         struct lttng_channel *channel = channel_file->private_data;
1029         int event_fd, ret;
1030         struct file *event_file;
1031         void *priv;
1032
1033         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1034         switch (event_param->instrumentation) {
1035         case LTTNG_KERNEL_KRETPROBE:
1036                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1037                 break;
1038         case LTTNG_KERNEL_KPROBE:
1039                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1040                 break;
1041         case LTTNG_KERNEL_FUNCTION:
1042                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1043                 break;
1044         default:
1045                 break;
1046         }
1047         event_fd = lttng_get_unused_fd();
1048         if (event_fd < 0) {
1049                 ret = event_fd;
1050                 goto fd_error;
1051         }
1052         event_file = anon_inode_getfile("[lttng_event]",
1053                                         &lttng_event_fops,
1054                                         NULL, O_RDWR);
1055         if (IS_ERR(event_file)) {
1056                 ret = PTR_ERR(event_file);
1057                 goto file_error;
1058         }
1059         /* The event holds a reference on the channel */
1060         if (atomic_long_add_unless(&channel_file->f_count,
1061                 1, INT_MAX) == INT_MAX) {
1062                 ret = -EOVERFLOW;
1063                 goto refcount_error;
1064         }
1065         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1066                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1067                 struct lttng_enabler *enabler;
1068
1069                 if (strutils_is_star_glob_pattern(event_param->name)) {
1070                         /*
1071                          * If the event name is a star globbing pattern,
1072                          * we create the special star globbing enabler.
1073                          */
1074                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1075                                 event_param, channel);
1076                 } else {
1077                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1078                                 event_param, channel);
1079                 }
1080                 priv = enabler;
1081         } else {
1082                 struct lttng_event *event;
1083
1084                 /*
1085                  * We tolerate no failure path after event creation. It
1086                  * will stay invariant for the rest of the session.
1087                  */
1088                 event = lttng_event_create(channel, event_param,
1089                                 NULL, NULL,
1090                                 event_param->instrumentation);
1091                 WARN_ON_ONCE(!event);
1092                 if (IS_ERR(event)) {
1093                         ret = PTR_ERR(event);
1094                         goto event_error;
1095                 }
1096                 priv = event;
1097         }
1098         event_file->private_data = priv;
1099         fd_install(event_fd, event_file);
1100         return event_fd;
1101
1102 event_error:
1103         atomic_long_dec(&channel_file->f_count);
1104 refcount_error:
1105         fput(event_file);
1106 file_error:
1107         put_unused_fd(event_fd);
1108 fd_error:
1109         return ret;
1110 }
1111
1112 /**
1113  *      lttng_channel_ioctl - lttng syscall through ioctl
1114  *
1115  *      @file: the file
1116  *      @cmd: the command
1117  *      @arg: command arg
1118  *
1119  *      This ioctl implements lttng commands:
1120  *      LTTNG_KERNEL_STREAM
1121  *              Returns an event stream file descriptor or failure.
1122  *              (typically, one event stream records events from one CPU)
1123  *      LTTNG_KERNEL_EVENT
1124  *              Returns an event file descriptor or failure.
1125  *      LTTNG_KERNEL_CONTEXT
1126  *              Prepend a context field to each event in the channel
1127  *      LTTNG_KERNEL_ENABLE
1128  *              Enable recording for events in this channel (weak enable)
1129  *      LTTNG_KERNEL_DISABLE
1130  *              Disable recording for events in this channel (strong disable)
1131  *
1132  * Channel and event file descriptors also hold a reference on the session.
1133  */
1134 static
1135 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1136 {
1137         struct lttng_channel *channel = file->private_data;
1138
1139         switch (cmd) {
1140         case LTTNG_KERNEL_OLD_STREAM:
1141         case LTTNG_KERNEL_STREAM:
1142                 return lttng_abi_open_stream(file);
1143         case LTTNG_KERNEL_OLD_EVENT:
1144         {
1145                 struct lttng_kernel_event *uevent_param;
1146                 struct lttng_kernel_old_event *old_uevent_param;
1147                 int ret;
1148
1149                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1150                                 GFP_KERNEL);
1151                 if (!uevent_param) {
1152                         ret = -ENOMEM;
1153                         goto old_event_end;
1154                 }
1155                 old_uevent_param = kmalloc(
1156                                 sizeof(struct lttng_kernel_old_event),
1157                                 GFP_KERNEL);
1158                 if (!old_uevent_param) {
1159                         ret = -ENOMEM;
1160                         goto old_event_error_free_param;
1161                 }
1162                 if (copy_from_user(old_uevent_param,
1163                                 (struct lttng_kernel_old_event __user *) arg,
1164                                 sizeof(struct lttng_kernel_old_event))) {
1165                         ret = -EFAULT;
1166                         goto old_event_error_free_old_param;
1167                 }
1168
1169                 memcpy(uevent_param->name, old_uevent_param->name,
1170                                 sizeof(uevent_param->name));
1171                 uevent_param->instrumentation =
1172                         old_uevent_param->instrumentation;
1173
1174                 switch (old_uevent_param->instrumentation) {
1175                 case LTTNG_KERNEL_KPROBE:
1176                         uevent_param->u.kprobe.addr =
1177                                 old_uevent_param->u.kprobe.addr;
1178                         uevent_param->u.kprobe.offset =
1179                                 old_uevent_param->u.kprobe.offset;
1180                         memcpy(uevent_param->u.kprobe.symbol_name,
1181                                 old_uevent_param->u.kprobe.symbol_name,
1182                                 sizeof(uevent_param->u.kprobe.symbol_name));
1183                         break;
1184                 case LTTNG_KERNEL_KRETPROBE:
1185                         uevent_param->u.kretprobe.addr =
1186                                 old_uevent_param->u.kretprobe.addr;
1187                         uevent_param->u.kretprobe.offset =
1188                                 old_uevent_param->u.kretprobe.offset;
1189                         memcpy(uevent_param->u.kretprobe.symbol_name,
1190                                 old_uevent_param->u.kretprobe.symbol_name,
1191                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1192                         break;
1193                 case LTTNG_KERNEL_FUNCTION:
1194                         memcpy(uevent_param->u.ftrace.symbol_name,
1195                                         old_uevent_param->u.ftrace.symbol_name,
1196                                         sizeof(uevent_param->u.ftrace.symbol_name));
1197                         break;
1198                 default:
1199                         break;
1200                 }
1201                 ret = lttng_abi_create_event(file, uevent_param);
1202
1203 old_event_error_free_old_param:
1204                 kfree(old_uevent_param);
1205 old_event_error_free_param:
1206                 kfree(uevent_param);
1207 old_event_end:
1208                 return ret;
1209         }
1210         case LTTNG_KERNEL_EVENT:
1211         {
1212                 struct lttng_kernel_event uevent_param;
1213
1214                 if (copy_from_user(&uevent_param,
1215                                 (struct lttng_kernel_event __user *) arg,
1216                                 sizeof(uevent_param)))
1217                         return -EFAULT;
1218                 return lttng_abi_create_event(file, &uevent_param);
1219         }
1220         case LTTNG_KERNEL_OLD_CONTEXT:
1221         {
1222                 struct lttng_kernel_context *ucontext_param;
1223                 struct lttng_kernel_old_context *old_ucontext_param;
1224                 int ret;
1225
1226                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1227                                 GFP_KERNEL);
1228                 if (!ucontext_param) {
1229                         ret = -ENOMEM;
1230                         goto old_ctx_end;
1231                 }
1232                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1233                                 GFP_KERNEL);
1234                 if (!old_ucontext_param) {
1235                         ret = -ENOMEM;
1236                         goto old_ctx_error_free_param;
1237                 }
1238
1239                 if (copy_from_user(old_ucontext_param,
1240                                 (struct lttng_kernel_old_context __user *) arg,
1241                                 sizeof(struct lttng_kernel_old_context))) {
1242                         ret = -EFAULT;
1243                         goto old_ctx_error_free_old_param;
1244                 }
1245                 ucontext_param->ctx = old_ucontext_param->ctx;
1246                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1247                                 sizeof(ucontext_param->padding));
1248                 /* only type that uses the union */
1249                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1250                         ucontext_param->u.perf_counter.type =
1251                                 old_ucontext_param->u.perf_counter.type;
1252                         ucontext_param->u.perf_counter.config =
1253                                 old_ucontext_param->u.perf_counter.config;
1254                         memcpy(ucontext_param->u.perf_counter.name,
1255                                 old_ucontext_param->u.perf_counter.name,
1256                                 sizeof(ucontext_param->u.perf_counter.name));
1257                 }
1258
1259                 ret = lttng_abi_add_context(file,
1260                                 ucontext_param,
1261                                 &channel->ctx, channel->session);
1262
1263 old_ctx_error_free_old_param:
1264                 kfree(old_ucontext_param);
1265 old_ctx_error_free_param:
1266                 kfree(ucontext_param);
1267 old_ctx_end:
1268                 return ret;
1269         }
1270         case LTTNG_KERNEL_CONTEXT:
1271         {
1272                 struct lttng_kernel_context ucontext_param;
1273
1274                 if (copy_from_user(&ucontext_param,
1275                                 (struct lttng_kernel_context __user *) arg,
1276                                 sizeof(ucontext_param)))
1277                         return -EFAULT;
1278                 return lttng_abi_add_context(file,
1279                                 &ucontext_param,
1280                                 &channel->ctx, channel->session);
1281         }
1282         case LTTNG_KERNEL_OLD_ENABLE:
1283         case LTTNG_KERNEL_ENABLE:
1284                 return lttng_channel_enable(channel);
1285         case LTTNG_KERNEL_OLD_DISABLE:
1286         case LTTNG_KERNEL_DISABLE:
1287                 return lttng_channel_disable(channel);
1288         case LTTNG_KERNEL_SYSCALL_MASK:
1289                 return lttng_channel_syscall_mask(channel,
1290                         (struct lttng_kernel_syscall_mask __user *) arg);
1291         default:
1292                 return -ENOIOCTLCMD;
1293         }
1294
1295 }
1296
1297 /**
1298  *      lttng_metadata_ioctl - lttng syscall through ioctl
1299  *
1300  *      @file: the file
1301  *      @cmd: the command
1302  *      @arg: command arg
1303  *
1304  *      This ioctl implements lttng commands:
1305  *      LTTNG_KERNEL_STREAM
1306  *              Returns an event stream file descriptor or failure.
1307  *
1308  * Channel and event file descriptors also hold a reference on the session.
1309  */
1310 static
1311 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1312 {
1313         switch (cmd) {
1314         case LTTNG_KERNEL_OLD_STREAM:
1315         case LTTNG_KERNEL_STREAM:
1316                 return lttng_abi_open_metadata_stream(file);
1317         default:
1318                 return -ENOIOCTLCMD;
1319         }
1320 }
1321
1322 /**
1323  *      lttng_channel_poll - lttng stream addition/removal monitoring
1324  *
1325  *      @file: the file
1326  *      @wait: poll table
1327  */
1328 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1329 {
1330         struct lttng_channel *channel = file->private_data;
1331         unsigned int mask = 0;
1332
1333         if (file->f_mode & FMODE_READ) {
1334                 poll_wait_set_exclusive(wait);
1335                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1336                           wait);
1337
1338                 if (channel->ops->is_disabled(channel->chan))
1339                         return POLLERR;
1340                 if (channel->ops->is_finalized(channel->chan))
1341                         return POLLHUP;
1342                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1343                         return POLLIN | POLLRDNORM;
1344                 return 0;
1345         }
1346         return mask;
1347
1348 }
1349
1350 static
1351 int lttng_channel_release(struct inode *inode, struct file *file)
1352 {
1353         struct lttng_channel *channel = file->private_data;
1354
1355         if (channel)
1356                 fput(channel->session->file);
1357         return 0;
1358 }
1359
1360 static
1361 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1362 {
1363         struct lttng_channel *channel = file->private_data;
1364
1365         if (channel) {
1366                 fput(channel->session->file);
1367                 lttng_metadata_channel_destroy(channel);
1368         }
1369
1370         return 0;
1371 }
1372
1373 static const struct file_operations lttng_channel_fops = {
1374         .owner = THIS_MODULE,
1375         .release = lttng_channel_release,
1376         .poll = lttng_channel_poll,
1377         .unlocked_ioctl = lttng_channel_ioctl,
1378 #ifdef CONFIG_COMPAT
1379         .compat_ioctl = lttng_channel_ioctl,
1380 #endif
1381 };
1382
1383 static const struct file_operations lttng_metadata_fops = {
1384         .owner = THIS_MODULE,
1385         .release = lttng_metadata_channel_release,
1386         .unlocked_ioctl = lttng_metadata_ioctl,
1387 #ifdef CONFIG_COMPAT
1388         .compat_ioctl = lttng_metadata_ioctl,
1389 #endif
1390 };
1391
1392 /**
1393  *      lttng_event_ioctl - lttng syscall through ioctl
1394  *
1395  *      @file: the file
1396  *      @cmd: the command
1397  *      @arg: command arg
1398  *
1399  *      This ioctl implements lttng commands:
1400  *      LTTNG_KERNEL_CONTEXT
1401  *              Prepend a context field to each record of this event
1402  *      LTTNG_KERNEL_ENABLE
1403  *              Enable recording for this event (weak enable)
1404  *      LTTNG_KERNEL_DISABLE
1405  *              Disable recording for this event (strong disable)
1406  */
1407 static
1408 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1409 {
1410         struct lttng_event *event;
1411         struct lttng_enabler *enabler;
1412         enum lttng_event_type *evtype = file->private_data;
1413
1414         switch (cmd) {
1415         case LTTNG_KERNEL_OLD_CONTEXT:
1416         {
1417                 /* Not implemented */
1418                 return -ENOSYS;
1419         }
1420         case LTTNG_KERNEL_CONTEXT:
1421         {
1422                 /* Not implemented */
1423                 return -ENOSYS;
1424         }
1425         case LTTNG_KERNEL_OLD_ENABLE:
1426         case LTTNG_KERNEL_ENABLE:
1427                 switch (*evtype) {
1428                 case LTTNG_TYPE_EVENT:
1429                         event = file->private_data;
1430                         return lttng_event_enable(event);
1431                 case LTTNG_TYPE_ENABLER:
1432                         enabler = file->private_data;
1433                         return lttng_enabler_enable(enabler);
1434                 default:
1435                         WARN_ON_ONCE(1);
1436                         return -ENOSYS;
1437                 }
1438         case LTTNG_KERNEL_OLD_DISABLE:
1439         case LTTNG_KERNEL_DISABLE:
1440                 switch (*evtype) {
1441                 case LTTNG_TYPE_EVENT:
1442                         event = file->private_data;
1443                         return lttng_event_disable(event);
1444                 case LTTNG_TYPE_ENABLER:
1445                         enabler = file->private_data;
1446                         return lttng_enabler_disable(enabler);
1447                 default:
1448                         WARN_ON_ONCE(1);
1449                         return -ENOSYS;
1450                 }
1451         case LTTNG_KERNEL_FILTER:
1452                 switch (*evtype) {
1453                 case LTTNG_TYPE_EVENT:
1454                         return -EINVAL;
1455                 case LTTNG_TYPE_ENABLER:
1456                 {
1457                         enabler = file->private_data;
1458                         return lttng_enabler_attach_bytecode(enabler,
1459                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1460                 }
1461
1462                 }
1463         default:
1464                 return -ENOIOCTLCMD;
1465         }
1466 }
1467
1468 static
1469 int lttng_event_release(struct inode *inode, struct file *file)
1470 {
1471         struct lttng_event *event;
1472         struct lttng_enabler *enabler;
1473         enum lttng_event_type *evtype = file->private_data;
1474
1475         if (!evtype)
1476                 return 0;
1477
1478         switch (*evtype) {
1479         case LTTNG_TYPE_EVENT:
1480                 event = file->private_data;
1481                 if (event)
1482                         fput(event->chan->file);
1483                 break;
1484         case LTTNG_TYPE_ENABLER:
1485                 enabler = file->private_data;
1486                 if (enabler)
1487                         fput(enabler->chan->file);
1488                 break;
1489         default:
1490                 WARN_ON_ONCE(1);
1491                 break;
1492         }
1493
1494         return 0;
1495 }
1496
1497 /* TODO: filter control ioctl */
1498 static const struct file_operations lttng_event_fops = {
1499         .owner = THIS_MODULE,
1500         .release = lttng_event_release,
1501         .unlocked_ioctl = lttng_event_ioctl,
1502 #ifdef CONFIG_COMPAT
1503         .compat_ioctl = lttng_event_ioctl,
1504 #endif
1505 };
1506
1507 static int put_u64(uint64_t val, unsigned long arg)
1508 {
1509         return put_user(val, (uint64_t __user *) arg);
1510 }
1511
1512 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1513                 unsigned int cmd, unsigned long arg)
1514 {
1515         struct lib_ring_buffer *buf = filp->private_data;
1516         struct channel *chan = buf->backend.chan;
1517         const struct lib_ring_buffer_config *config = &chan->backend.config;
1518         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1519         int ret;
1520
1521         if (atomic_read(&chan->record_disabled))
1522                 return -EIO;
1523
1524         switch (cmd) {
1525         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1526         {
1527                 uint64_t ts;
1528
1529                 ret = ops->timestamp_begin(config, buf, &ts);
1530                 if (ret < 0)
1531                         goto error;
1532                 return put_u64(ts, arg);
1533         }
1534         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1535         {
1536                 uint64_t ts;
1537
1538                 ret = ops->timestamp_end(config, buf, &ts);
1539                 if (ret < 0)
1540                         goto error;
1541                 return put_u64(ts, arg);
1542         }
1543         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1544         {
1545                 uint64_t ed;
1546
1547                 ret = ops->events_discarded(config, buf, &ed);
1548                 if (ret < 0)
1549                         goto error;
1550                 return put_u64(ed, arg);
1551         }
1552         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1553         {
1554                 uint64_t cs;
1555
1556                 ret = ops->content_size(config, buf, &cs);
1557                 if (ret < 0)
1558                         goto error;
1559                 return put_u64(cs, arg);
1560         }
1561         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1562         {
1563                 uint64_t ps;
1564
1565                 ret = ops->packet_size(config, buf, &ps);
1566                 if (ret < 0)
1567                         goto error;
1568                 return put_u64(ps, arg);
1569         }
1570         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1571         {
1572                 uint64_t si;
1573
1574                 ret = ops->stream_id(config, buf, &si);
1575                 if (ret < 0)
1576                         goto error;
1577                 return put_u64(si, arg);
1578         }
1579         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1580         {
1581                 uint64_t ts;
1582
1583                 ret = ops->current_timestamp(config, buf, &ts);
1584                 if (ret < 0)
1585                         goto error;
1586                 return put_u64(ts, arg);
1587         }
1588         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1589         {
1590                 uint64_t seq;
1591
1592                 ret = ops->sequence_number(config, buf, &seq);
1593                 if (ret < 0)
1594                         goto error;
1595                 return put_u64(seq, arg);
1596         }
1597         case LTTNG_RING_BUFFER_INSTANCE_ID:
1598         {
1599                 uint64_t id;
1600
1601                 ret = ops->instance_id(config, buf, &id);
1602                 if (ret < 0)
1603                         goto error;
1604                 return put_u64(id, arg);
1605         }
1606         default:
1607                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1608                                 cmd, arg);
1609         }
1610
1611 error:
1612         return -ENOSYS;
1613 }
1614
1615 #ifdef CONFIG_COMPAT
1616 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1617                 unsigned int cmd, unsigned long arg)
1618 {
1619         struct lib_ring_buffer *buf = filp->private_data;
1620         struct channel *chan = buf->backend.chan;
1621         const struct lib_ring_buffer_config *config = &chan->backend.config;
1622         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1623         int ret;
1624
1625         if (atomic_read(&chan->record_disabled))
1626                 return -EIO;
1627
1628         switch (cmd) {
1629         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1630         {
1631                 uint64_t ts;
1632
1633                 ret = ops->timestamp_begin(config, buf, &ts);
1634                 if (ret < 0)
1635                         goto error;
1636                 return put_u64(ts, arg);
1637         }
1638         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1639         {
1640                 uint64_t ts;
1641
1642                 ret = ops->timestamp_end(config, buf, &ts);
1643                 if (ret < 0)
1644                         goto error;
1645                 return put_u64(ts, arg);
1646         }
1647         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1648         {
1649                 uint64_t ed;
1650
1651                 ret = ops->events_discarded(config, buf, &ed);
1652                 if (ret < 0)
1653                         goto error;
1654                 return put_u64(ed, arg);
1655         }
1656         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1657         {
1658                 uint64_t cs;
1659
1660                 ret = ops->content_size(config, buf, &cs);
1661                 if (ret < 0)
1662                         goto error;
1663                 return put_u64(cs, arg);
1664         }
1665         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1666         {
1667                 uint64_t ps;
1668
1669                 ret = ops->packet_size(config, buf, &ps);
1670                 if (ret < 0)
1671                         goto error;
1672                 return put_u64(ps, arg);
1673         }
1674         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1675         {
1676                 uint64_t si;
1677
1678                 ret = ops->stream_id(config, buf, &si);
1679                 if (ret < 0)
1680                         goto error;
1681                 return put_u64(si, arg);
1682         }
1683         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1684         {
1685                 uint64_t ts;
1686
1687                 ret = ops->current_timestamp(config, buf, &ts);
1688                 if (ret < 0)
1689                         goto error;
1690                 return put_u64(ts, arg);
1691         }
1692         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1693         {
1694                 uint64_t seq;
1695
1696                 ret = ops->sequence_number(config, buf, &seq);
1697                 if (ret < 0)
1698                         goto error;
1699                 return put_u64(seq, arg);
1700         }
1701         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1702         {
1703                 uint64_t id;
1704
1705                 ret = ops->instance_id(config, buf, &id);
1706                 if (ret < 0)
1707                         goto error;
1708                 return put_u64(id, arg);
1709         }
1710         default:
1711                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1712                                 cmd, arg);
1713         }
1714
1715 error:
1716         return -ENOSYS;
1717 }
1718 #endif /* CONFIG_COMPAT */
1719
1720 static void lttng_stream_override_ring_buffer_fops(void)
1721 {
1722         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1723         lttng_stream_ring_buffer_file_operations.open =
1724                 lib_ring_buffer_file_operations.open;
1725         lttng_stream_ring_buffer_file_operations.release =
1726                 lib_ring_buffer_file_operations.release;
1727         lttng_stream_ring_buffer_file_operations.poll =
1728                 lib_ring_buffer_file_operations.poll;
1729         lttng_stream_ring_buffer_file_operations.splice_read =
1730                 lib_ring_buffer_file_operations.splice_read;
1731         lttng_stream_ring_buffer_file_operations.mmap =
1732                 lib_ring_buffer_file_operations.mmap;
1733         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1734                 lttng_stream_ring_buffer_ioctl;
1735         lttng_stream_ring_buffer_file_operations.llseek =
1736                 lib_ring_buffer_file_operations.llseek;
1737 #ifdef CONFIG_COMPAT
1738         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1739                 lttng_stream_ring_buffer_compat_ioctl;
1740 #endif
1741 }
1742
1743 int __init lttng_abi_init(void)
1744 {
1745         int ret = 0;
1746
1747         wrapper_vmalloc_sync_all();
1748         lttng_clock_ref();
1749         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1750                                         &lttng_fops, NULL);
1751
1752         if (!lttng_proc_dentry) {
1753                 printk(KERN_ERR "Error creating LTTng control file\n");
1754                 ret = -ENOMEM;
1755                 goto error;
1756         }
1757         lttng_stream_override_ring_buffer_fops();
1758         return 0;
1759
1760 error:
1761         lttng_clock_unref();
1762         return ret;
1763 }
1764
1765 /* No __exit annotation because used by init error path too. */
1766 void lttng_abi_exit(void)
1767 {
1768         lttng_clock_unref();
1769         if (lttng_proc_dentry)
1770                 remove_proc_entry("lttng", NULL);
1771 }