src/lttng-abi.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-abi.c
   4  *
   5  * LTTng ABI
   6  *
   7  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Mimic system calls for:
  10  * - session creation, returns a file descriptor or failure.
  11  *   - channel creation, returns a file descriptor or failure.
  12  *     - Operates on a session file descriptor
  13  *     - Takes all channel options as parameters.
  14  *   - stream get, returns a file descriptor or failure.
  15  *     - Operates on a channel file descriptor.
  16  *   - stream notifier get, returns a file descriptor or failure.
  17  *     - Operates on a channel file descriptor.
  18  *   - event creation, returns a file descriptor or failure.
  19  *     - Operates on a channel file descriptor
  20  *     - Takes an event name as parameter
  21  *     - Takes an instrumentation source as parameter
  22  *       - e.g. tracepoints, dynamic_probes...
  23  *     - Takes instrumentation source specific arguments.
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/anon_inodes.h>
  29 #include <linux/file.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/slab.h>
  32 #include <linux/err.h>
  33 #include <wrapper/vmalloc.h>    /* for wrapper_vmalloc_sync_mappings() */
  34 #include <ringbuffer/vfs.h>
  35 #include <ringbuffer/backend.h>
  36 #include <ringbuffer/frontend.h>
  37 #include <wrapper/poll.h>
  38 #include <wrapper/file.h>
  39 #include <wrapper/kref.h>
  40 #include <lttng/string-utils.h>
  41 #include <lttng/abi.h>
  42 #include <lttng/abi-old.h>
  43 #include <lttng/events.h>
  44 #include <lttng/tracer.h>
  45 #include <lttng/tp-mempool.h>
  46 #include <ringbuffer/frontend_types.h>
  47
  48 /*
  49  * This is LTTng's own personal way to create a system call as an external
  50  * module. We use ioctl() on /proc/lttng.
  51  */
  52
  53 static struct proc_dir_entry *lttng_proc_dentry;
  54
  55 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0))
  56 static const struct proc_ops lttng_proc_ops;
  57 #else
  58 static const struct file_operations lttng_proc_ops;
  59 #endif
  60
  61 static const struct file_operations lttng_session_fops;
  62 static const struct file_operations lttng_channel_fops;
  63 static const struct file_operations lttng_metadata_fops;
  64 static const struct file_operations lttng_event_fops;
  65 static struct file_operations lttng_stream_ring_buffer_file_operations;
  66
  67 static int put_u64(uint64_t val, unsigned long arg);
  68 static int put_u32(uint32_t val, unsigned long arg);
  69
  70 /*
  71  * Teardown management: opened file descriptors keep a refcount on the module,
  72  * so it can only exit when all file descriptors are closed.
  73  */
  74
  75 static
  76 int lttng_abi_create_session(void)
  77 {
  78         struct lttng_session *session;
  79         struct file *session_file;
  80         int session_fd, ret;
  81
  82         session = lttng_session_create();
  83         if (!session)
  84                 return -ENOMEM;
  85         session_fd = lttng_get_unused_fd();
  86         if (session_fd < 0) {
  87                 ret = session_fd;
  88                 goto fd_error;
  89         }
  90         session_file = anon_inode_getfile("[lttng_session]",
  91                                           &lttng_session_fops,
  92                                           session, O_RDWR);
  93         if (IS_ERR(session_file)) {
  94                 ret = PTR_ERR(session_file);
  95                 goto file_error;
  96         }
  97         session->file = session_file;
  98         fd_install(session_fd, session_file);
  99         return session_fd;
 100
 101 file_error:
 102         put_unused_fd(session_fd);
 103 fd_error:
 104         lttng_session_destroy(session);
 105         return ret;
 106 }
 107
 108 static
 109 int lttng_abi_tracepoint_list(void)
 110 {
 111         struct file *tracepoint_list_file;
 112         int file_fd, ret;
 113
 114         file_fd = lttng_get_unused_fd();
 115         if (file_fd < 0) {
 116                 ret = file_fd;
 117                 goto fd_error;
 118         }
 119
 120         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 121                                           &lttng_tracepoint_list_fops,
 122                                           NULL, O_RDWR);
 123         if (IS_ERR(tracepoint_list_file)) {
 124                 ret = PTR_ERR(tracepoint_list_file);
 125                 goto file_error;
 126         }
 127         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 128         if (ret < 0)
 129                 goto open_error;
 130         fd_install(file_fd, tracepoint_list_file);
 131         return file_fd;
 132
 133 open_error:
 134         fput(tracepoint_list_file);
 135 file_error:
 136         put_unused_fd(file_fd);
 137 fd_error:
 138         return ret;
 139 }
 140
 141 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 142 static inline
 143 int lttng_abi_syscall_list(void)
 144 {
 145         return -ENOSYS;
 146 }
 147 #else
 148 static
 149 int lttng_abi_syscall_list(void)
 150 {
 151         struct file *syscall_list_file;
 152         int file_fd, ret;
 153
 154         file_fd = lttng_get_unused_fd();
 155         if (file_fd < 0) {
 156                 ret = file_fd;
 157                 goto fd_error;
 158         }
 159
 160         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 161                                           &lttng_syscall_list_fops,
 162                                           NULL, O_RDWR);
 163         if (IS_ERR(syscall_list_file)) {
 164                 ret = PTR_ERR(syscall_list_file);
 165                 goto file_error;
 166         }
 167         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 168         if (ret < 0)
 169                 goto open_error;
 170         fd_install(file_fd, syscall_list_file);
 171         return file_fd;
 172
 173 open_error:
 174         fput(syscall_list_file);
 175 file_error:
 176         put_unused_fd(file_fd);
 177 fd_error:
 178         return ret;
 179 }
 180 #endif
 181
 182 static
 183 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 184 {
 185         v->major = LTTNG_MODULES_MAJOR_VERSION;
 186         v->minor = LTTNG_MODULES_MINOR_VERSION;
 187         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 188 }
 189
 190 static
 191 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 192 {
 193         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 194         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 195 }
 196
 197 static
 198 long lttng_abi_add_context(struct file *file,
 199         struct lttng_kernel_context *context_param,
 200         struct lttng_ctx **ctx, struct lttng_session *session)
 201 {
 202
 203         if (session->been_active)
 204                 return -EPERM;
 205
 206         switch (context_param->ctx) {
 207         case LTTNG_KERNEL_CONTEXT_PID:
 208                 return lttng_add_pid_to_ctx(ctx);
 209         case LTTNG_KERNEL_CONTEXT_PRIO:
 210                 return lttng_add_prio_to_ctx(ctx);
 211         case LTTNG_KERNEL_CONTEXT_NICE:
 212                 return lttng_add_nice_to_ctx(ctx);
 213         case LTTNG_KERNEL_CONTEXT_VPID:
 214                 return lttng_add_vpid_to_ctx(ctx);
 215         case LTTNG_KERNEL_CONTEXT_TID:
 216                 return lttng_add_tid_to_ctx(ctx);
 217         case LTTNG_KERNEL_CONTEXT_VTID:
 218                 return lttng_add_vtid_to_ctx(ctx);
 219         case LTTNG_KERNEL_CONTEXT_PPID:
 220                 return lttng_add_ppid_to_ctx(ctx);
 221         case LTTNG_KERNEL_CONTEXT_VPPID:
 222                 return lttng_add_vppid_to_ctx(ctx);
 223         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 224                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 225                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 226                                 context_param->u.perf_counter.config,
 227                                 context_param->u.perf_counter.name,
 228                                 ctx);
 229         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 230                 return lttng_add_procname_to_ctx(ctx);
 231         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 232                 return lttng_add_hostname_to_ctx(ctx);
 233         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 234                 return lttng_add_cpu_id_to_ctx(ctx);
 235         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 236                 return lttng_add_interruptible_to_ctx(ctx);
 237         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 238                 return lttng_add_need_reschedule_to_ctx(ctx);
 239         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 240                 return lttng_add_preemptible_to_ctx(ctx);
 241         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 242                 return lttng_add_migratable_to_ctx(ctx);
 243         case LTTNG_KERNEL_CONTEXT_CALLSTACK_KERNEL:
 244         case LTTNG_KERNEL_CONTEXT_CALLSTACK_USER:
 245                 return lttng_add_callstack_to_ctx(ctx, context_param->ctx);
 246         case LTTNG_KERNEL_CONTEXT_CGROUP_NS:
 247                 return lttng_add_cgroup_ns_to_ctx(ctx);
 248         case LTTNG_KERNEL_CONTEXT_IPC_NS:
 249                 return lttng_add_ipc_ns_to_ctx(ctx);
 250         case LTTNG_KERNEL_CONTEXT_MNT_NS:
 251                 return lttng_add_mnt_ns_to_ctx(ctx);
 252         case LTTNG_KERNEL_CONTEXT_NET_NS:
 253                 return lttng_add_net_ns_to_ctx(ctx);
 254         case LTTNG_KERNEL_CONTEXT_PID_NS:
 255                 return lttng_add_pid_ns_to_ctx(ctx);
 256         case LTTNG_KERNEL_CONTEXT_USER_NS:
 257                 return lttng_add_user_ns_to_ctx(ctx);
 258         case LTTNG_KERNEL_CONTEXT_UTS_NS:
 259                 return lttng_add_uts_ns_to_ctx(ctx);
 260         case LTTNG_KERNEL_CONTEXT_UID:
 261                 return lttng_add_uid_to_ctx(ctx);
 262         case LTTNG_KERNEL_CONTEXT_EUID:
 263                 return lttng_add_euid_to_ctx(ctx);
 264         case LTTNG_KERNEL_CONTEXT_SUID:
 265                 return lttng_add_suid_to_ctx(ctx);
 266         case LTTNG_KERNEL_CONTEXT_GID:
 267                 return lttng_add_gid_to_ctx(ctx);
 268         case LTTNG_KERNEL_CONTEXT_EGID:
 269                 return lttng_add_egid_to_ctx(ctx);
 270         case LTTNG_KERNEL_CONTEXT_SGID:
 271                 return lttng_add_sgid_to_ctx(ctx);
 272         case LTTNG_KERNEL_CONTEXT_VUID:
 273                 return lttng_add_vuid_to_ctx(ctx);
 274         case LTTNG_KERNEL_CONTEXT_VEUID:
 275                 return lttng_add_veuid_to_ctx(ctx);
 276         case LTTNG_KERNEL_CONTEXT_VSUID:
 277                 return lttng_add_vsuid_to_ctx(ctx);
 278         case LTTNG_KERNEL_CONTEXT_VGID:
 279                 return lttng_add_vgid_to_ctx(ctx);
 280         case LTTNG_KERNEL_CONTEXT_VEGID:
 281                 return lttng_add_vegid_to_ctx(ctx);
 282         case LTTNG_KERNEL_CONTEXT_VSGID:
 283                 return lttng_add_vsgid_to_ctx(ctx);
 284         case LTTNG_KERNEL_CONTEXT_TIME_NS:
 285                 return lttng_add_time_ns_to_ctx(ctx);
 286         default:
 287                 return -EINVAL;
 288         }
 289 }
 290
 291 /**
 292  *      lttng_ioctl - lttng syscall through ioctl
 293  *
 294  *      @file: the file
 295  *      @cmd: the command
 296  *      @arg: command arg
 297  *
 298  *      This ioctl implements lttng commands:
 299  *      LTTNG_KERNEL_SESSION
 300  *              Returns a LTTng trace session file descriptor
 301  *      LTTNG_KERNEL_TRACER_VERSION
 302  *              Returns the LTTng kernel tracer version
 303  *      LTTNG_KERNEL_TRACEPOINT_LIST
 304  *              Returns a file descriptor listing available tracepoints
 305  *      LTTNG_KERNEL_WAIT_QUIESCENT
 306  *              Returns after all previously running probes have completed
 307  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 308  *              Returns the LTTng kernel tracer ABI version
 309  *
 310  * The returned session will be deleted when its file descriptor is closed.
 311  */
 312 static
 313 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 314 {
 315         switch (cmd) {
 316         case LTTNG_KERNEL_OLD_SESSION:
 317         case LTTNG_KERNEL_SESSION:
 318                 return lttng_abi_create_session();
 319         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 320         {
 321                 struct lttng_kernel_tracer_version v;
 322                 struct lttng_kernel_old_tracer_version oldv;
 323                 struct lttng_kernel_old_tracer_version *uversion =
 324                         (struct lttng_kernel_old_tracer_version __user *) arg;
 325
 326                 lttng_abi_tracer_version(&v);
 327                 oldv.major = v.major;
 328                 oldv.minor = v.minor;
 329                 oldv.patchlevel = v.patchlevel;
 330
 331                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 332                         return -EFAULT;
 333                 return 0;
 334         }
 335         case LTTNG_KERNEL_TRACER_VERSION:
 336         {
 337                 struct lttng_kernel_tracer_version version;
 338                 struct lttng_kernel_tracer_version *uversion =
 339                         (struct lttng_kernel_tracer_version __user *) arg;
 340
 341                 lttng_abi_tracer_version(&version);
 342
 343                 if (copy_to_user(uversion, &version, sizeof(version)))
 344                         return -EFAULT;
 345                 return 0;
 346         }
 347         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 348         {
 349                 struct lttng_kernel_tracer_abi_version version;
 350                 struct lttng_kernel_tracer_abi_version *uversion =
 351                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 352
 353                 lttng_abi_tracer_abi_version(&version);
 354
 355                 if (copy_to_user(uversion, &version, sizeof(version)))
 356                         return -EFAULT;
 357                 return 0;
 358         }
 359         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 360         case LTTNG_KERNEL_TRACEPOINT_LIST:
 361                 return lttng_abi_tracepoint_list();
 362         case LTTNG_KERNEL_SYSCALL_LIST:
 363                 return lttng_abi_syscall_list();
 364         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 365         case LTTNG_KERNEL_WAIT_QUIESCENT:
 366                 synchronize_trace();
 367                 return 0;
 368         case LTTNG_KERNEL_OLD_CALIBRATE:
 369         {
 370                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 371                         (struct lttng_kernel_old_calibrate __user *) arg;
 372                 struct lttng_kernel_old_calibrate old_calibrate;
 373                 struct lttng_kernel_calibrate calibrate;
 374                 int ret;
 375
 376                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 377                         return -EFAULT;
 378                 calibrate.type = old_calibrate.type;
 379                 ret = lttng_calibrate(&calibrate);
 380                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 381                         return -EFAULT;
 382                 return ret;
 383         }
 384         case LTTNG_KERNEL_CALIBRATE:
 385         {
 386                 struct lttng_kernel_calibrate __user *ucalibrate =
 387                         (struct lttng_kernel_calibrate __user *) arg;
 388                 struct lttng_kernel_calibrate calibrate;
 389                 int ret;
 390
 391                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 392                         return -EFAULT;
 393                 ret = lttng_calibrate(&calibrate);
 394                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 395                         return -EFAULT;
 396                 return ret;
 397         }
 398         default:
 399                 return -ENOIOCTLCMD;
 400         }
 401 }
 402
 403 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0))
 404 static const struct proc_ops lttng_proc_ops = {
 405         .proc_ioctl = lttng_ioctl,
 406 #ifdef CONFIG_COMPAT
 407         .proc_compat_ioctl = lttng_ioctl,
 408 #endif /* CONFIG_COMPAT */
 409 };
 410 #else
 411 static const struct file_operations lttng_proc_ops = {
 412         .owner = THIS_MODULE,
 413         .unlocked_ioctl = lttng_ioctl,
 414 #ifdef CONFIG_COMPAT
 415         .compat_ioctl = lttng_ioctl,
 416 #endif /* CONFIG_COMPAT */
 417 };
 418 #endif
 419
 420 static
 421 int lttng_abi_create_channel(struct file *session_file,
 422                              struct lttng_kernel_channel *chan_param,
 423                              enum channel_type channel_type)
 424 {
 425         struct lttng_session *session = session_file->private_data;
 426         const struct file_operations *fops = NULL;
 427         const char *transport_name;
 428         struct lttng_channel *chan;
 429         struct file *chan_file;
 430         int chan_fd;
 431         int ret = 0;
 432
 433         chan_fd = lttng_get_unused_fd();
 434         if (chan_fd < 0) {
 435                 ret = chan_fd;
 436                 goto fd_error;
 437         }
 438         switch (channel_type) {
 439         case PER_CPU_CHANNEL:
 440                 fops = &lttng_channel_fops;
 441                 break;
 442         case METADATA_CHANNEL:
 443                 fops = &lttng_metadata_fops;
 444                 break;
 445         }
 446
 447         chan_file = anon_inode_getfile("[lttng_channel]",
 448                                        fops,
 449                                        NULL, O_RDWR);
 450         if (IS_ERR(chan_file)) {
 451                 ret = PTR_ERR(chan_file);
 452                 goto file_error;
 453         }
 454         switch (channel_type) {
 455         case PER_CPU_CHANNEL:
 456                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 457                         transport_name = chan_param->overwrite ?
 458                                 "relay-overwrite" : "relay-discard";
 459                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 460                         transport_name = chan_param->overwrite ?
 461                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 462                 } else {
 463                         return -EINVAL;
 464                 }
 465                 break;
 466         case METADATA_CHANNEL:
 467                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 468                         transport_name = "relay-metadata";
 469                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 470                         transport_name = "relay-metadata-mmap";
 471                 else
 472                         return -EINVAL;
 473                 break;
 474         default:
 475                 transport_name = "<unknown>";
 476                 break;
 477         }
 478         if (!atomic_long_add_unless(&session_file->f_count, 1, LONG_MAX)) {
 479                 ret = -EOVERFLOW;
 480                 goto refcount_error;
 481         }
 482         /*
 483          * We tolerate no failure path after channel creation. It will stay
 484          * invariant for the rest of the session.
 485          */
 486         chan = lttng_channel_create(session, transport_name, NULL,
 487                                   chan_param->subbuf_size,
 488                                   chan_param->num_subbuf,
 489                                   chan_param->switch_timer_interval,
 490                                   chan_param->read_timer_interval,
 491                                   channel_type);
 492         if (!chan) {
 493                 ret = -EINVAL;
 494                 goto chan_error;
 495         }
 496         chan->file = chan_file;
 497         chan_file->private_data = chan;
 498         fd_install(chan_fd, chan_file);
 499
 500         return chan_fd;
 501
 502 chan_error:
 503         atomic_long_dec(&session_file->f_count);
 504 refcount_error:
 505         fput(chan_file);
 506 file_error:
 507         put_unused_fd(chan_fd);
 508 fd_error:
 509         return ret;
 510 }
 511
 512 static
 513 int lttng_abi_session_set_name(struct lttng_session *session,
 514                 struct lttng_kernel_session_name *name)
 515 {
 516         size_t len;
 517
 518         len = strnlen(name->name, LTTNG_KERNEL_SESSION_NAME_LEN);
 519
 520         if (len == LTTNG_KERNEL_SESSION_NAME_LEN) {
 521                 /* Name is too long/malformed */
 522                 return -EINVAL;
 523         }
 524
 525         strcpy(session->name, name->name);
 526         return 0;
 527 }
 528
 529 static
 530 int lttng_abi_session_set_creation_time(struct lttng_session *session,
 531                 struct lttng_kernel_session_creation_time *time)
 532 {
 533         size_t len;
 534
 535         len = strnlen(time->iso8601, LTTNG_KERNEL_SESSION_CREATION_TIME_ISO8601_LEN);
 536
 537         if (len == LTTNG_KERNEL_SESSION_CREATION_TIME_ISO8601_LEN) {
 538                 /* Time is too long/malformed */
 539                 return -EINVAL;
 540         }
 541
 542         strcpy(session->creation_time, time->iso8601);
 543         return 0;
 544 }
 545
 546 static
 547 enum tracker_type get_tracker_type(struct lttng_kernel_tracker_args *tracker)
 548 {
 549         switch (tracker->type) {
 550         case LTTNG_KERNEL_TRACKER_PID:
 551                 return TRACKER_PID;
 552         case LTTNG_KERNEL_TRACKER_VPID:
 553                 return TRACKER_VPID;
 554         case LTTNG_KERNEL_TRACKER_UID:
 555                 return TRACKER_UID;
 556         case LTTNG_KERNEL_TRACKER_VUID:
 557                 return TRACKER_VUID;
 558         case LTTNG_KERNEL_TRACKER_GID:
 559                 return TRACKER_GID;
 560         case LTTNG_KERNEL_TRACKER_VGID:
 561                 return TRACKER_VGID;
 562         default:
 563                 return TRACKER_UNKNOWN;
 564         }
 565 }
 566
 567 /**
 568  *      lttng_session_ioctl - lttng session fd ioctl
 569  *
 570  *      @file: the file
 571  *      @cmd: the command
 572  *      @arg: command arg
 573  *
 574  *      This ioctl implements lttng commands:
 575  *      LTTNG_KERNEL_CHANNEL
 576  *              Returns a LTTng channel file descriptor
 577  *      LTTNG_KERNEL_ENABLE
 578  *              Enables tracing for a session (weak enable)
 579  *      LTTNG_KERNEL_DISABLE
 580  *              Disables tracing for a session (strong disable)
 581  *      LTTNG_KERNEL_METADATA
 582  *              Returns a LTTng metadata file descriptor
 583  *      LTTNG_KERNEL_SESSION_TRACK_PID
 584  *              Add PID to session PID tracker
 585  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 586  *              Remove PID from session PID tracker
 587  *      LTTNG_KERNEL_SESSION_TRACK_ID
 588  *              Add ID to tracker
 589  *      LTTNG_KERNEL_SESSION_UNTRACK_ID
 590  *              Remove ID from tracker
 591  *
 592  * The returned channel will be deleted when its file descriptor is closed.
 593  */
 594 static
 595 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 596 {
 597         struct lttng_session *session = file->private_data;
 598         struct lttng_kernel_channel chan_param;
 599         struct lttng_kernel_old_channel old_chan_param;
 600
 601         switch (cmd) {
 602         case LTTNG_KERNEL_OLD_CHANNEL:
 603         {
 604                 if (copy_from_user(&old_chan_param,
 605                                 (struct lttng_kernel_old_channel __user *) arg,
 606                                 sizeof(struct lttng_kernel_old_channel)))
 607                         return -EFAULT;
 608                 chan_param.overwrite = old_chan_param.overwrite;
 609                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 610                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 611                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 612                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 613                 chan_param.output = old_chan_param.output;
 614
 615                 return lttng_abi_create_channel(file, &chan_param,
 616                                 PER_CPU_CHANNEL);
 617         }
 618         case LTTNG_KERNEL_CHANNEL:
 619         {
 620                 if (copy_from_user(&chan_param,
 621                                 (struct lttng_kernel_channel __user *) arg,
 622                                 sizeof(struct lttng_kernel_channel)))
 623                         return -EFAULT;
 624                 return lttng_abi_create_channel(file, &chan_param,
 625                                 PER_CPU_CHANNEL);
 626         }
 627         case LTTNG_KERNEL_OLD_SESSION_START:
 628         case LTTNG_KERNEL_OLD_ENABLE:
 629         case LTTNG_KERNEL_SESSION_START:
 630         case LTTNG_KERNEL_ENABLE:
 631                 return lttng_session_enable(session);
 632         case LTTNG_KERNEL_OLD_SESSION_STOP:
 633         case LTTNG_KERNEL_OLD_DISABLE:
 634         case LTTNG_KERNEL_SESSION_STOP:
 635         case LTTNG_KERNEL_DISABLE:
 636                 return lttng_session_disable(session);
 637         case LTTNG_KERNEL_OLD_METADATA:
 638         {
 639                 if (copy_from_user(&old_chan_param,
 640                                 (struct lttng_kernel_old_channel __user *) arg,
 641                                 sizeof(struct lttng_kernel_old_channel)))
 642                         return -EFAULT;
 643                 chan_param.overwrite = old_chan_param.overwrite;
 644                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 645                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 646                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 647                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 648                 chan_param.output = old_chan_param.output;
 649
 650                 return lttng_abi_create_channel(file, &chan_param,
 651                                 METADATA_CHANNEL);
 652         }
 653         case LTTNG_KERNEL_METADATA:
 654         {
 655                 if (copy_from_user(&chan_param,
 656                                         (struct lttng_kernel_channel __user *) arg,
 657                                         sizeof(struct lttng_kernel_channel)))
 658                         return -EFAULT;
 659                 return lttng_abi_create_channel(file, &chan_param,
 660                                 METADATA_CHANNEL);
 661         }
 662         case LTTNG_KERNEL_SESSION_TRACK_PID:
 663                 return lttng_session_track_id(session, TRACKER_PID, (int) arg);
 664         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 665                 return lttng_session_untrack_id(session, TRACKER_PID, (int) arg);
 666         case LTTNG_KERNEL_SESSION_TRACK_ID:
 667         {
 668                 struct lttng_kernel_tracker_args tracker;
 669                 enum tracker_type tracker_type;
 670
 671                 if (copy_from_user(&tracker,
 672                                 (struct lttng_kernel_tracker_args __user *) arg,
 673                                 sizeof(struct lttng_kernel_tracker_args)))
 674                         return -EFAULT;
 675                 tracker_type = get_tracker_type(&tracker);
 676                 if (tracker_type == TRACKER_UNKNOWN)
 677                         return -EINVAL;
 678                 return lttng_session_track_id(session, tracker_type, tracker.id);
 679         }
 680         case LTTNG_KERNEL_SESSION_UNTRACK_ID:
 681         {
 682                 struct lttng_kernel_tracker_args tracker;
 683                 enum tracker_type tracker_type;
 684
 685                 if (copy_from_user(&tracker,
 686                                 (struct lttng_kernel_tracker_args __user *) arg,
 687                                 sizeof(struct lttng_kernel_tracker_args)))
 688                         return -EFAULT;
 689                 tracker_type = get_tracker_type(&tracker);
 690                 if (tracker_type == TRACKER_UNKNOWN)
 691                         return -EINVAL;
 692                 return lttng_session_untrack_id(session, tracker_type,
 693                                 tracker.id);
 694         }
 695         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 696                 return lttng_session_list_tracker_ids(session, TRACKER_PID);
 697         case LTTNG_KERNEL_SESSION_LIST_TRACKER_IDS:
 698         {
 699                 struct lttng_kernel_tracker_args tracker;
 700                 enum tracker_type tracker_type;
 701
 702                 if (copy_from_user(&tracker,
 703                                 (struct lttng_kernel_tracker_args __user *) arg,
 704                                 sizeof(struct lttng_kernel_tracker_args)))
 705                         return -EFAULT;
 706                 tracker_type = get_tracker_type(&tracker);
 707                 if (tracker_type == TRACKER_UNKNOWN)
 708                         return -EINVAL;
 709                 return lttng_session_list_tracker_ids(session, tracker_type);
 710         }
 711         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 712                 return lttng_session_metadata_regenerate(session);
 713         case LTTNG_KERNEL_SESSION_STATEDUMP:
 714                 return lttng_session_statedump(session);
 715         case LTTNG_KERNEL_SESSION_SET_NAME:
 716         {
 717                 struct lttng_kernel_session_name name;
 718
 719                 if (copy_from_user(&name,
 720                                 (struct lttng_kernel_session_name __user *) arg,
 721                                 sizeof(struct lttng_kernel_session_name)))
 722                         return -EFAULT;
 723                 return lttng_abi_session_set_name(session, &name);
 724         }
 725         case LTTNG_KERNEL_SESSION_SET_CREATION_TIME:
 726         {
 727                 struct lttng_kernel_session_creation_time time;
 728
 729                 if (copy_from_user(&time,
 730                                 (struct lttng_kernel_session_creation_time __user *) arg,
 731                                 sizeof(struct lttng_kernel_session_creation_time)))
 732                         return -EFAULT;
 733                 return lttng_abi_session_set_creation_time(session, &time);
 734         }
 735         default:
 736                 return -ENOIOCTLCMD;
 737         }
 738 }
 739
 740 /*
 741  * Called when the last file reference is dropped.
 742  *
 743  * Big fat note: channels and events are invariant for the whole session after
 744  * their creation. So this session destruction also destroys all channel and
 745  * event structures specific to this session (they are not destroyed when their
 746  * individual file is released).
 747  */
 748 static
 749 int lttng_session_release(struct inode *inode, struct file *file)
 750 {
 751         struct lttng_session *session = file->private_data;
 752
 753         if (session)
 754                 lttng_session_destroy(session);
 755         return 0;
 756 }
 757
 758 static const struct file_operations lttng_session_fops = {
 759         .owner = THIS_MODULE,
 760         .release = lttng_session_release,
 761         .unlocked_ioctl = lttng_session_ioctl,
 762 #ifdef CONFIG_COMPAT
 763         .compat_ioctl = lttng_session_ioctl,
 764 #endif
 765 };
 766
 767 /**
 768  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 769  *      @filp: the file
 770  *      @wait: poll table
 771  *
 772  *      Handles the poll operations for the metadata channels.
 773  */
 774 static
 775 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 776                 poll_table *wait)
 777 {
 778         struct lttng_metadata_stream *stream = filp->private_data;
 779         struct lib_ring_buffer *buf = stream->priv;
 780         int finalized;
 781         unsigned int mask = 0;
 782
 783         if (filp->f_mode & FMODE_READ) {
 784                 poll_wait_set_exclusive(wait);
 785                 poll_wait(filp, &stream->read_wait, wait);
 786
 787                 finalized = stream->finalized;
 788
 789                 /*
 790                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 791                  * ordering finalized load before offsets loads.
 792                  */
 793                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 794
 795                 if (finalized)
 796                         mask |= POLLHUP;
 797
 798                 mutex_lock(&stream->metadata_cache->lock);
 799                 if (stream->metadata_cache->metadata_written >
 800                                 stream->metadata_out)
 801                         mask |= POLLIN;
 802                 mutex_unlock(&stream->metadata_cache->lock);
 803         }
 804
 805         return mask;
 806 }
 807
 808 static
 809 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 810                 unsigned int cmd, unsigned long arg)
 811 {
 812         struct lttng_metadata_stream *stream = filp->private_data;
 813
 814         stream->metadata_out = stream->metadata_in;
 815 }
 816
 817 /*
 818  * Reset the counter of how much metadata has been consumed to 0. That way,
 819  * the consumer receives the content of the metadata cache unchanged. This is
 820  * different from the metadata_regenerate where the offset from epoch is
 821  * resampled, here we want the exact same content as the last time the metadata
 822  * was generated. This command is only possible if all the metadata written
 823  * in the cache has been output to the metadata stream to avoid corrupting the
 824  * metadata file.
 825  *
 826  * Return 0 on success, a negative value on error.
 827  */
 828 static
 829 int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
 830 {
 831         int ret;
 832         struct lttng_metadata_cache *cache = stream->metadata_cache;
 833
 834         mutex_lock(&cache->lock);
 835         if (stream->metadata_out != cache->metadata_written) {
 836                 ret = -EBUSY;
 837                 goto end;
 838         }
 839         stream->metadata_out = 0;
 840         stream->metadata_in = 0;
 841         wake_up_interruptible(&stream->read_wait);
 842         ret = 0;
 843
 844 end:
 845         mutex_unlock(&cache->lock);
 846         return ret;
 847 }
 848
 849 static
 850 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 851                 unsigned int cmd, unsigned long arg)
 852 {
 853         int ret;
 854         struct lttng_metadata_stream *stream = filp->private_data;
 855         struct lib_ring_buffer *buf = stream->priv;
 856         unsigned int rb_cmd;
 857         bool coherent;
 858
 859         if (cmd == RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK)
 860                 rb_cmd = RING_BUFFER_GET_NEXT_SUBBUF;
 861         else
 862                 rb_cmd = cmd;
 863
 864         switch (cmd) {
 865         case RING_BUFFER_GET_NEXT_SUBBUF:
 866         {
 867                 struct lttng_metadata_stream *stream = filp->private_data;
 868                 struct lib_ring_buffer *buf = stream->priv;
 869                 struct channel *chan = buf->backend.chan;
 870
 871                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 872                 if (ret > 0) {
 873                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 874                         ret = 0;
 875                 } else if (ret < 0)
 876                         goto err;
 877                 break;
 878         }
 879         case RING_BUFFER_GET_SUBBUF:
 880         {
 881                 /*
 882                  * Random access is not allowed for metadata channel.
 883                  */
 884                 return -ENOSYS;
 885         }
 886         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 887         case RING_BUFFER_FLUSH:
 888         {
 889                 struct lttng_metadata_stream *stream = filp->private_data;
 890                 struct lib_ring_buffer *buf = stream->priv;
 891                 struct channel *chan = buf->backend.chan;
 892
 893                 /*
 894                  * Before doing the actual ring buffer flush, write up to one
 895                  * packet of metadata in the ring buffer.
 896                  */
 897                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 898                 if (ret < 0)
 899                         goto err;
 900                 break;
 901         }
 902         case RING_BUFFER_GET_METADATA_VERSION:
 903         {
 904                 struct lttng_metadata_stream *stream = filp->private_data;
 905
 906                 return put_u64(stream->version, arg);
 907         }
 908         case RING_BUFFER_METADATA_CACHE_DUMP:
 909         {
 910                 struct lttng_metadata_stream *stream = filp->private_data;
 911
 912                 return lttng_metadata_cache_dump(stream);
 913         }
 914         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
 915         {
 916                 struct lttng_metadata_stream *stream = filp->private_data;
 917                 struct lib_ring_buffer *buf = stream->priv;
 918                 struct channel *chan = buf->backend.chan;
 919
 920                 ret = lttng_metadata_output_channel(stream, chan, &coherent);
 921                 if (ret > 0) {
 922                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 923                         ret = 0;
 924                 } else if (ret < 0) {
 925                         goto err;
 926                 }
 927                 break;
 928         }
 929         default:
 930                 break;
 931         }
 932         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 933
 934         /* Performing lib ring buffer ioctl after our own. */
 935         ret = lib_ring_buffer_ioctl(filp, rb_cmd, arg, buf);
 936         if (ret < 0)
 937                 goto err;
 938
 939         switch (cmd) {
 940         case RING_BUFFER_PUT_NEXT_SUBBUF:
 941         {
 942                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 943                                 cmd, arg);
 944                 break;
 945         }
 946         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
 947         {
 948                 return put_u32(coherent, arg);
 949         }
 950         default:
 951                 break;
 952         }
 953 err:
 954         return ret;
 955 }
 956
 957 #ifdef CONFIG_COMPAT
 958 static
 959 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 960                 unsigned int cmd, unsigned long arg)
 961 {
 962         int ret;
 963         struct lttng_metadata_stream *stream = filp->private_data;
 964         struct lib_ring_buffer *buf = stream->priv;
 965         unsigned int rb_cmd;
 966         bool coherent;
 967
 968         if (cmd == RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK)
 969                 rb_cmd = RING_BUFFER_GET_NEXT_SUBBUF;
 970         else
 971                 rb_cmd = cmd;
 972
 973         switch (cmd) {
 974         case RING_BUFFER_GET_NEXT_SUBBUF:
 975         {
 976                 struct lttng_metadata_stream *stream = filp->private_data;
 977                 struct lib_ring_buffer *buf = stream->priv;
 978                 struct channel *chan = buf->backend.chan;
 979
 980                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 981                 if (ret > 0) {
 982                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 983                         ret = 0;
 984                 } else if (ret < 0)
 985                         goto err;
 986                 break;
 987         }
 988         case RING_BUFFER_GET_SUBBUF:
 989         {
 990                 /*
 991                  * Random access is not allowed for metadata channel.
 992                  */
 993                 return -ENOSYS;
 994         }
 995         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 996         case RING_BUFFER_FLUSH:
 997         {
 998                 struct lttng_metadata_stream *stream = filp->private_data;
 999                 struct lib_ring_buffer *buf = stream->priv;
1000                 struct channel *chan = buf->backend.chan;
1001
1002                 /*
1003                  * Before doing the actual ring buffer flush, write up to one
1004                  * packet of metadata in the ring buffer.
1005                  */
1006                 ret = lttng_metadata_output_channel(stream, chan, NULL);
1007                 if (ret < 0)
1008                         goto err;
1009                 break;
1010         }
1011         case RING_BUFFER_GET_METADATA_VERSION:
1012         {
1013                 struct lttng_metadata_stream *stream = filp->private_data;
1014
1015                 return put_u64(stream->version, arg);
1016         }
1017         case RING_BUFFER_METADATA_CACHE_DUMP:
1018         {
1019                 struct lttng_metadata_stream *stream = filp->private_data;
1020
1021                 return lttng_metadata_cache_dump(stream);
1022         }
1023         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
1024         {
1025                 struct lttng_metadata_stream *stream = filp->private_data;
1026                 struct lib_ring_buffer *buf = stream->priv;
1027                 struct channel *chan = buf->backend.chan;
1028
1029                 ret = lttng_metadata_output_channel(stream, chan, &coherent);
1030                 if (ret > 0) {
1031                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
1032                         ret = 0;
1033                 } else if (ret < 0) {
1034                         goto err;
1035                 }
1036                 break;
1037         }
1038         default:
1039                 break;
1040         }
1041         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
1042
1043         /* Performing lib ring buffer ioctl after our own. */
1044         ret = lib_ring_buffer_compat_ioctl(filp, rb_cmd, arg, buf);
1045         if (ret < 0)
1046                 goto err;
1047
1048         switch (cmd) {
1049         case RING_BUFFER_PUT_NEXT_SUBBUF:
1050         {
1051                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
1052                                 cmd, arg);
1053                 break;
1054         }
1055         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
1056         {
1057                 return put_u32(coherent, arg);
1058         }
1059         default:
1060                 break;
1061         }
1062 err:
1063         return ret;
1064 }
1065 #endif
1066
1067 /*
1068  * This is not used by anonymous file descriptors. This code is left
1069  * there if we ever want to implement an inode with open() operation.
1070  */
1071 static
1072 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
1073 {
1074         struct lttng_metadata_stream *stream = inode->i_private;
1075         struct lib_ring_buffer *buf = stream->priv;
1076
1077         file->private_data = buf;
1078         /*
1079          * Since life-time of metadata cache differs from that of
1080          * session, we need to keep our own reference on the transport.
1081          */
1082         if (!try_module_get(stream->transport->owner)) {
1083                 printk(KERN_WARNING "LTTng: Can't lock transport module.\n");
1084                 return -EBUSY;
1085         }
1086         return lib_ring_buffer_open(inode, file, buf);
1087 }
1088
1089 static
1090 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
1091 {
1092         struct lttng_metadata_stream *stream = file->private_data;
1093         struct lib_ring_buffer *buf = stream->priv;
1094
1095         mutex_lock(&stream->metadata_cache->lock);
1096         list_del(&stream->list);
1097         mutex_unlock(&stream->metadata_cache->lock);
1098         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
1099         module_put(stream->transport->owner);
1100         kfree(stream);
1101         return lib_ring_buffer_release(inode, file, buf);
1102 }
1103
1104 static
1105 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
1106                 struct pipe_inode_info *pipe, size_t len,
1107                 unsigned int flags)
1108 {
1109         struct lttng_metadata_stream *stream = in->private_data;
1110         struct lib_ring_buffer *buf = stream->priv;
1111
1112         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
1113                         flags, buf);
1114 }
1115
1116 static
1117 int lttng_metadata_ring_buffer_mmap(struct file *filp,
1118                 struct vm_area_struct *vma)
1119 {
1120         struct lttng_metadata_stream *stream = filp->private_data;
1121         struct lib_ring_buffer *buf = stream->priv;
1122
1123         return lib_ring_buffer_mmap(filp, vma, buf);
1124 }
1125
1126 static
1127 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
1128         .owner = THIS_MODULE,
1129         .open = lttng_metadata_ring_buffer_open,
1130         .release = lttng_metadata_ring_buffer_release,
1131         .poll = lttng_metadata_ring_buffer_poll,
1132         .splice_read = lttng_metadata_ring_buffer_splice_read,
1133         .mmap = lttng_metadata_ring_buffer_mmap,
1134         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
1135         .llseek = vfs_lib_ring_buffer_no_llseek,
1136 #ifdef CONFIG_COMPAT
1137         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
1138 #endif
1139 };
1140
1141 static
1142 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
1143                 const struct file_operations *fops)
1144 {
1145         int stream_fd, ret;
1146         struct file *stream_file;
1147
1148         stream_fd = lttng_get_unused_fd();
1149         if (stream_fd < 0) {
1150                 ret = stream_fd;
1151                 goto fd_error;
1152         }
1153         stream_file = anon_inode_getfile("[lttng_stream]", fops,
1154                         stream_priv, O_RDWR);
1155         if (IS_ERR(stream_file)) {
1156                 ret = PTR_ERR(stream_file);
1157                 goto file_error;
1158         }
1159         /*
1160          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
1161          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
1162          * file descriptor, so we set FMODE_PREAD here.
1163          */
1164         stream_file->f_mode |= FMODE_PREAD;
1165         fd_install(stream_fd, stream_file);
1166         /*
1167          * The stream holds a reference to the channel within the generic ring
1168          * buffer library, so no need to hold a refcount on the channel and
1169          * session files here.
1170          */
1171         return stream_fd;
1172
1173 file_error:
1174         put_unused_fd(stream_fd);
1175 fd_error:
1176         return ret;
1177 }
1178
1179 static
1180 int lttng_abi_open_stream(struct file *channel_file)
1181 {
1182         struct lttng_channel *channel = channel_file->private_data;
1183         struct lib_ring_buffer *buf;
1184         int ret;
1185         void *stream_priv;
1186
1187         buf = channel->ops->buffer_read_open(channel->chan);
1188         if (!buf)
1189                 return -ENOENT;
1190
1191         stream_priv = buf;
1192         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1193                         &lttng_stream_ring_buffer_file_operations);
1194         if (ret < 0)
1195                 goto fd_error;
1196
1197         return ret;
1198
1199 fd_error:
1200         channel->ops->buffer_read_close(buf);
1201         return ret;
1202 }
1203
1204 static
1205 int lttng_abi_open_metadata_stream(struct file *channel_file)
1206 {
1207         struct lttng_channel *channel = channel_file->private_data;
1208         struct lttng_session *session = channel->session;
1209         struct lib_ring_buffer *buf;
1210         int ret;
1211         struct lttng_metadata_stream *metadata_stream;
1212         void *stream_priv;
1213
1214         buf = channel->ops->buffer_read_open(channel->chan);
1215         if (!buf)
1216                 return -ENOENT;
1217
1218         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
1219                         GFP_KERNEL);
1220         if (!metadata_stream) {
1221                 ret = -ENOMEM;
1222                 goto nomem;
1223         }
1224         metadata_stream->metadata_cache = session->metadata_cache;
1225         init_waitqueue_head(&metadata_stream->read_wait);
1226         metadata_stream->priv = buf;
1227         stream_priv = metadata_stream;
1228         metadata_stream->transport = channel->transport;
1229         /* Initial state is an empty metadata, considered as incoherent. */
1230         metadata_stream->coherent = false;
1231
1232         /*
1233          * Since life-time of metadata cache differs from that of
1234          * session, we need to keep our own reference on the transport.
1235          */
1236         if (!try_module_get(metadata_stream->transport->owner)) {
1237                 printk(KERN_WARNING "LTTng: Can't lock transport module.\n");
1238                 ret = -EINVAL;
1239                 goto notransport;
1240         }
1241
1242         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1243                 ret = -EOVERFLOW;
1244                 goto kref_error;
1245         }
1246
1247         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1248                         &lttng_metadata_ring_buffer_file_operations);
1249         if (ret < 0)
1250                 goto fd_error;
1251
1252         mutex_lock(&session->metadata_cache->lock);
1253         list_add(&metadata_stream->list,
1254                 &session->metadata_cache->metadata_stream);
1255         mutex_unlock(&session->metadata_cache->lock);
1256         return ret;
1257
1258 fd_error:
1259         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1260 kref_error:
1261         module_put(metadata_stream->transport->owner);
1262 notransport:
1263         kfree(metadata_stream);
1264 nomem:
1265         channel->ops->buffer_read_close(buf);
1266         return ret;
1267 }
1268
1269 static
1270 int lttng_abi_create_event(struct file *channel_file,
1271                            struct lttng_kernel_event *event_param)
1272 {
1273         struct lttng_channel *channel = channel_file->private_data;
1274         int event_fd, ret;
1275         struct file *event_file;
1276         void *priv;
1277
1278         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1279         switch (event_param->instrumentation) {
1280         case LTTNG_KERNEL_KRETPROBE:
1281                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1282                 break;
1283         case LTTNG_KERNEL_KPROBE:
1284                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1285                 break;
1286         case LTTNG_KERNEL_FUNCTION:
1287                 WARN_ON_ONCE(1);
1288                 /* Not implemented. */
1289                 break;
1290         default:
1291                 break;
1292         }
1293         event_fd = lttng_get_unused_fd();
1294         if (event_fd < 0) {
1295                 ret = event_fd;
1296                 goto fd_error;
1297         }
1298         event_file = anon_inode_getfile("[lttng_event]",
1299                                         &lttng_event_fops,
1300                                         NULL, O_RDWR);
1301         if (IS_ERR(event_file)) {
1302                 ret = PTR_ERR(event_file);
1303                 goto file_error;
1304         }
1305         /* The event holds a reference on the channel */
1306         if (!atomic_long_add_unless(&channel_file->f_count, 1, LONG_MAX)) {
1307                 ret = -EOVERFLOW;
1308                 goto refcount_error;
1309         }
1310         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1311                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1312                 struct lttng_enabler *enabler;
1313
1314                 if (strutils_is_star_glob_pattern(event_param->name)) {
1315                         /*
1316                          * If the event name is a star globbing pattern,
1317                          * we create the special star globbing enabler.
1318                          */
1319                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1320                                 event_param, channel);
1321                 } else {
1322                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1323                                 event_param, channel);
1324                 }
1325                 priv = enabler;
1326         } else {
1327                 struct lttng_event *event;
1328
1329                 /*
1330                  * We tolerate no failure path after event creation. It
1331                  * will stay invariant for the rest of the session.
1332                  */
1333                 event = lttng_event_create(channel, event_param,
1334                                 NULL, NULL,
1335                                 event_param->instrumentation);
1336                 WARN_ON_ONCE(!event);
1337                 if (IS_ERR(event)) {
1338                         ret = PTR_ERR(event);
1339                         goto event_error;
1340                 }
1341                 priv = event;
1342         }
1343         event_file->private_data = priv;
1344         fd_install(event_fd, event_file);
1345         return event_fd;
1346
1347 event_error:
1348         atomic_long_dec(&channel_file->f_count);
1349 refcount_error:
1350         fput(event_file);
1351 file_error:
1352         put_unused_fd(event_fd);
1353 fd_error:
1354         return ret;
1355 }
1356
1357 /**
1358  *      lttng_channel_ioctl - lttng syscall through ioctl
1359  *
1360  *      @file: the file
1361  *      @cmd: the command
1362  *      @arg: command arg
1363  *
1364  *      This ioctl implements lttng commands:
1365  *      LTTNG_KERNEL_STREAM
1366  *              Returns an event stream file descriptor or failure.
1367  *              (typically, one event stream records events from one CPU)
1368  *      LTTNG_KERNEL_EVENT
1369  *              Returns an event file descriptor or failure.
1370  *      LTTNG_KERNEL_CONTEXT
1371  *              Prepend a context field to each event in the channel
1372  *      LTTNG_KERNEL_ENABLE
1373  *              Enable recording for events in this channel (weak enable)
1374  *      LTTNG_KERNEL_DISABLE
1375  *              Disable recording for events in this channel (strong disable)
1376  *
1377  * Channel and event file descriptors also hold a reference on the session.
1378  */
1379 static
1380 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1381 {
1382         struct lttng_channel *channel = file->private_data;
1383
1384         switch (cmd) {
1385         case LTTNG_KERNEL_OLD_STREAM:
1386         case LTTNG_KERNEL_STREAM:
1387                 return lttng_abi_open_stream(file);
1388         case LTTNG_KERNEL_OLD_EVENT:
1389         {
1390                 struct lttng_kernel_event *uevent_param;
1391                 struct lttng_kernel_old_event *old_uevent_param;
1392                 int ret;
1393
1394                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1395                                 GFP_KERNEL);
1396                 if (!uevent_param) {
1397                         ret = -ENOMEM;
1398                         goto old_event_end;
1399                 }
1400                 old_uevent_param = kmalloc(
1401                                 sizeof(struct lttng_kernel_old_event),
1402                                 GFP_KERNEL);
1403                 if (!old_uevent_param) {
1404                         ret = -ENOMEM;
1405                         goto old_event_error_free_param;
1406                 }
1407                 if (copy_from_user(old_uevent_param,
1408                                 (struct lttng_kernel_old_event __user *) arg,
1409                                 sizeof(struct lttng_kernel_old_event))) {
1410                         ret = -EFAULT;
1411                         goto old_event_error_free_old_param;
1412                 }
1413
1414                 memcpy(uevent_param->name, old_uevent_param->name,
1415                                 sizeof(uevent_param->name));
1416                 uevent_param->instrumentation =
1417                         old_uevent_param->instrumentation;
1418
1419                 switch (old_uevent_param->instrumentation) {
1420                 case LTTNG_KERNEL_KPROBE:
1421                         uevent_param->u.kprobe.addr =
1422                                 old_uevent_param->u.kprobe.addr;
1423                         uevent_param->u.kprobe.offset =
1424                                 old_uevent_param->u.kprobe.offset;
1425                         memcpy(uevent_param->u.kprobe.symbol_name,
1426                                 old_uevent_param->u.kprobe.symbol_name,
1427                                 sizeof(uevent_param->u.kprobe.symbol_name));
1428                         break;
1429                 case LTTNG_KERNEL_KRETPROBE:
1430                         uevent_param->u.kretprobe.addr =
1431                                 old_uevent_param->u.kretprobe.addr;
1432                         uevent_param->u.kretprobe.offset =
1433                                 old_uevent_param->u.kretprobe.offset;
1434                         memcpy(uevent_param->u.kretprobe.symbol_name,
1435                                 old_uevent_param->u.kretprobe.symbol_name,
1436                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1437                         break;
1438                 case LTTNG_KERNEL_FUNCTION:
1439                         WARN_ON_ONCE(1);
1440                         /* Not implemented. */
1441                         break;
1442                 default:
1443                         break;
1444                 }
1445                 ret = lttng_abi_create_event(file, uevent_param);
1446
1447 old_event_error_free_old_param:
1448                 kfree(old_uevent_param);
1449 old_event_error_free_param:
1450                 kfree(uevent_param);
1451 old_event_end:
1452                 return ret;
1453         }
1454         case LTTNG_KERNEL_EVENT:
1455         {
1456                 struct lttng_kernel_event uevent_param;
1457
1458                 if (copy_from_user(&uevent_param,
1459                                 (struct lttng_kernel_event __user *) arg,
1460                                 sizeof(uevent_param)))
1461                         return -EFAULT;
1462                 return lttng_abi_create_event(file, &uevent_param);
1463         }
1464         case LTTNG_KERNEL_OLD_CONTEXT:
1465         {
1466                 struct lttng_kernel_context *ucontext_param;
1467                 struct lttng_kernel_old_context *old_ucontext_param;
1468                 int ret;
1469
1470                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1471                                 GFP_KERNEL);
1472                 if (!ucontext_param) {
1473                         ret = -ENOMEM;
1474                         goto old_ctx_end;
1475                 }
1476                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1477                                 GFP_KERNEL);
1478                 if (!old_ucontext_param) {
1479                         ret = -ENOMEM;
1480                         goto old_ctx_error_free_param;
1481                 }
1482
1483                 if (copy_from_user(old_ucontext_param,
1484                                 (struct lttng_kernel_old_context __user *) arg,
1485                                 sizeof(struct lttng_kernel_old_context))) {
1486                         ret = -EFAULT;
1487                         goto old_ctx_error_free_old_param;
1488                 }
1489                 ucontext_param->ctx = old_ucontext_param->ctx;
1490                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1491                                 sizeof(ucontext_param->padding));
1492                 /* only type that uses the union */
1493                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1494                         ucontext_param->u.perf_counter.type =
1495                                 old_ucontext_param->u.perf_counter.type;
1496                         ucontext_param->u.perf_counter.config =
1497                                 old_ucontext_param->u.perf_counter.config;
1498                         memcpy(ucontext_param->u.perf_counter.name,
1499                                 old_ucontext_param->u.perf_counter.name,
1500                                 sizeof(ucontext_param->u.perf_counter.name));
1501                 }
1502
1503                 ret = lttng_abi_add_context(file,
1504                                 ucontext_param,
1505                                 &channel->ctx, channel->session);
1506
1507 old_ctx_error_free_old_param:
1508                 kfree(old_ucontext_param);
1509 old_ctx_error_free_param:
1510                 kfree(ucontext_param);
1511 old_ctx_end:
1512                 return ret;
1513         }
1514         case LTTNG_KERNEL_CONTEXT:
1515         {
1516                 struct lttng_kernel_context ucontext_param;
1517
1518                 if (copy_from_user(&ucontext_param,
1519                                 (struct lttng_kernel_context __user *) arg,
1520                                 sizeof(ucontext_param)))
1521                         return -EFAULT;
1522                 return lttng_abi_add_context(file,
1523                                 &ucontext_param,
1524                                 &channel->ctx, channel->session);
1525         }
1526         case LTTNG_KERNEL_OLD_ENABLE:
1527         case LTTNG_KERNEL_ENABLE:
1528                 return lttng_channel_enable(channel);
1529         case LTTNG_KERNEL_OLD_DISABLE:
1530         case LTTNG_KERNEL_DISABLE:
1531                 return lttng_channel_disable(channel);
1532         case LTTNG_KERNEL_SYSCALL_MASK:
1533                 return lttng_channel_syscall_mask(channel,
1534                         (struct lttng_kernel_syscall_mask __user *) arg);
1535         default:
1536                 return -ENOIOCTLCMD;
1537         }
1538 }
1539
1540 /**
1541  *      lttng_metadata_ioctl - lttng syscall through ioctl
1542  *
1543  *      @file: the file
1544  *      @cmd: the command
1545  *      @arg: command arg
1546  *
1547  *      This ioctl implements lttng commands:
1548  *      LTTNG_KERNEL_STREAM
1549  *              Returns an event stream file descriptor or failure.
1550  *
1551  * Channel and event file descriptors also hold a reference on the session.
1552  */
1553 static
1554 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1555 {
1556         switch (cmd) {
1557         case LTTNG_KERNEL_OLD_STREAM:
1558         case LTTNG_KERNEL_STREAM:
1559                 return lttng_abi_open_metadata_stream(file);
1560         default:
1561                 return -ENOIOCTLCMD;
1562         }
1563 }
1564
1565 /**
1566  *      lttng_channel_poll - lttng stream addition/removal monitoring
1567  *
1568  *      @file: the file
1569  *      @wait: poll table
1570  */
1571 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1572 {
1573         struct lttng_channel *channel = file->private_data;
1574         unsigned int mask = 0;
1575
1576         if (file->f_mode & FMODE_READ) {
1577                 poll_wait_set_exclusive(wait);
1578                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1579                           wait);
1580
1581                 if (channel->ops->is_disabled(channel->chan))
1582                         return POLLERR;
1583                 if (channel->ops->is_finalized(channel->chan))
1584                         return POLLHUP;
1585                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1586                         return POLLIN | POLLRDNORM;
1587                 return 0;
1588         }
1589         return mask;
1590
1591 }
1592
1593 static
1594 int lttng_channel_release(struct inode *inode, struct file *file)
1595 {
1596         struct lttng_channel *channel = file->private_data;
1597
1598         if (channel)
1599                 fput(channel->session->file);
1600         return 0;
1601 }
1602
1603 static
1604 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1605 {
1606         struct lttng_channel *channel = file->private_data;
1607
1608         if (channel) {
1609                 fput(channel->session->file);
1610                 lttng_metadata_channel_destroy(channel);
1611         }
1612
1613         return 0;
1614 }
1615
1616 static const struct file_operations lttng_channel_fops = {
1617         .owner = THIS_MODULE,
1618         .release = lttng_channel_release,
1619         .poll = lttng_channel_poll,
1620         .unlocked_ioctl = lttng_channel_ioctl,
1621 #ifdef CONFIG_COMPAT
1622         .compat_ioctl = lttng_channel_ioctl,
1623 #endif
1624 };
1625
1626 static const struct file_operations lttng_metadata_fops = {
1627         .owner = THIS_MODULE,
1628         .release = lttng_metadata_channel_release,
1629         .unlocked_ioctl = lttng_metadata_ioctl,
1630 #ifdef CONFIG_COMPAT
1631         .compat_ioctl = lttng_metadata_ioctl,
1632 #endif
1633 };
1634
1635 /**
1636  *      lttng_event_ioctl - lttng syscall through ioctl
1637  *
1638  *      @file: the file
1639  *      @cmd: the command
1640  *      @arg: command arg
1641  *
1642  *      This ioctl implements lttng commands:
1643  *      LTTNG_KERNEL_CONTEXT
1644  *              Prepend a context field to each record of this event
1645  *      LTTNG_KERNEL_ENABLE
1646  *              Enable recording for this event (weak enable)
1647  *      LTTNG_KERNEL_DISABLE
1648  *              Disable recording for this event (strong disable)
1649  */
1650 static
1651 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1652 {
1653         struct lttng_event *event;
1654         struct lttng_enabler *enabler;
1655         enum lttng_event_type *evtype = file->private_data;
1656
1657         switch (cmd) {
1658         case LTTNG_KERNEL_OLD_CONTEXT:
1659         {
1660                 /* Not implemented */
1661                 return -ENOSYS;
1662         }
1663         case LTTNG_KERNEL_CONTEXT:
1664         {
1665                 /* Not implemented */
1666                 return -ENOSYS;
1667         }
1668         case LTTNG_KERNEL_OLD_ENABLE:
1669         case LTTNG_KERNEL_ENABLE:
1670                 switch (*evtype) {
1671                 case LTTNG_TYPE_EVENT:
1672                         event = file->private_data;
1673                         return lttng_event_enable(event);
1674                 case LTTNG_TYPE_ENABLER:
1675                         enabler = file->private_data;
1676                         return lttng_enabler_enable(enabler);
1677                 default:
1678                         WARN_ON_ONCE(1);
1679                         return -ENOSYS;
1680                 }
1681         case LTTNG_KERNEL_OLD_DISABLE:
1682         case LTTNG_KERNEL_DISABLE:
1683                 switch (*evtype) {
1684                 case LTTNG_TYPE_EVENT:
1685                         event = file->private_data;
1686                         return lttng_event_disable(event);
1687                 case LTTNG_TYPE_ENABLER:
1688                         enabler = file->private_data;
1689                         return lttng_enabler_disable(enabler);
1690                 default:
1691                         WARN_ON_ONCE(1);
1692                         return -ENOSYS;
1693                 }
1694         case LTTNG_KERNEL_FILTER:
1695                 switch (*evtype) {
1696                 case LTTNG_TYPE_EVENT:
1697                         return -EINVAL;
1698                 case LTTNG_TYPE_ENABLER:
1699                 {
1700                         enabler = file->private_data;
1701                         return lttng_enabler_attach_bytecode(enabler,
1702                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1703                 }
1704                 default:
1705                         WARN_ON_ONCE(1);
1706                         return -ENOSYS;
1707                 }
1708         case LTTNG_KERNEL_ADD_CALLSITE:
1709                 switch (*evtype) {
1710                 case LTTNG_TYPE_EVENT:
1711                         event = file->private_data;
1712                         return lttng_event_add_callsite(event,
1713                                 (struct lttng_kernel_event_callsite __user *) arg);
1714                 case LTTNG_TYPE_ENABLER:
1715                         return -EINVAL;
1716                 default:
1717                         WARN_ON_ONCE(1);
1718                         return -ENOSYS;
1719                 }
1720         default:
1721                 return -ENOIOCTLCMD;
1722         }
1723 }
1724
1725 static
1726 int lttng_event_release(struct inode *inode, struct file *file)
1727 {
1728         struct lttng_event *event;
1729         struct lttng_enabler *enabler;
1730         enum lttng_event_type *evtype = file->private_data;
1731
1732         if (!evtype)
1733                 return 0;
1734
1735         switch (*evtype) {
1736         case LTTNG_TYPE_EVENT:
1737                 event = file->private_data;
1738                 if (event)
1739                         fput(event->chan->file);
1740                 break;
1741         case LTTNG_TYPE_ENABLER:
1742                 enabler = file->private_data;
1743                 if (enabler)
1744                         fput(enabler->chan->file);
1745                 break;
1746         default:
1747                 WARN_ON_ONCE(1);
1748                 break;
1749         }
1750
1751         return 0;
1752 }
1753
1754 /* TODO: filter control ioctl */
1755 static const struct file_operations lttng_event_fops = {
1756         .owner = THIS_MODULE,
1757         .release = lttng_event_release,
1758         .unlocked_ioctl = lttng_event_ioctl,
1759 #ifdef CONFIG_COMPAT
1760         .compat_ioctl = lttng_event_ioctl,
1761 #endif
1762 };
1763
1764 static int put_u64(uint64_t val, unsigned long arg)
1765 {
1766         return put_user(val, (uint64_t __user *) arg);
1767 }
1768
1769 static int put_u32(uint32_t val, unsigned long arg)
1770 {
1771         return put_user(val, (uint32_t __user *) arg);
1772 }
1773
1774 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1775                 unsigned int cmd, unsigned long arg)
1776 {
1777         struct lib_ring_buffer *buf = filp->private_data;
1778         struct channel *chan = buf->backend.chan;
1779         const struct lib_ring_buffer_config *config = &chan->backend.config;
1780         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1781         int ret;
1782
1783         if (atomic_read(&chan->record_disabled))
1784                 return -EIO;
1785
1786         switch (cmd) {
1787         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1788         {
1789                 uint64_t ts;
1790
1791                 ret = ops->timestamp_begin(config, buf, &ts);
1792                 if (ret < 0)
1793                         goto error;
1794                 return put_u64(ts, arg);
1795         }
1796         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1797         {
1798                 uint64_t ts;
1799
1800                 ret = ops->timestamp_end(config, buf, &ts);
1801                 if (ret < 0)
1802                         goto error;
1803                 return put_u64(ts, arg);
1804         }
1805         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1806         {
1807                 uint64_t ed;
1808
1809                 ret = ops->events_discarded(config, buf, &ed);
1810                 if (ret < 0)
1811                         goto error;
1812                 return put_u64(ed, arg);
1813         }
1814         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1815         {
1816                 uint64_t cs;
1817
1818                 ret = ops->content_size(config, buf, &cs);
1819                 if (ret < 0)
1820                         goto error;
1821                 return put_u64(cs, arg);
1822         }
1823         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1824         {
1825                 uint64_t ps;
1826
1827                 ret = ops->packet_size(config, buf, &ps);
1828                 if (ret < 0)
1829                         goto error;
1830                 return put_u64(ps, arg);
1831         }
1832         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1833         {
1834                 uint64_t si;
1835
1836                 ret = ops->stream_id(config, buf, &si);
1837                 if (ret < 0)
1838                         goto error;
1839                 return put_u64(si, arg);
1840         }
1841         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1842         {
1843                 uint64_t ts;
1844
1845                 ret = ops->current_timestamp(config, buf, &ts);
1846                 if (ret < 0)
1847                         goto error;
1848                 return put_u64(ts, arg);
1849         }
1850         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1851         {
1852                 uint64_t seq;
1853
1854                 ret = ops->sequence_number(config, buf, &seq);
1855                 if (ret < 0)
1856                         goto error;
1857                 return put_u64(seq, arg);
1858         }
1859         case LTTNG_RING_BUFFER_INSTANCE_ID:
1860         {
1861                 uint64_t id;
1862
1863                 ret = ops->instance_id(config, buf, &id);
1864                 if (ret < 0)
1865                         goto error;
1866                 return put_u64(id, arg);
1867         }
1868         default:
1869                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1870                                 cmd, arg);
1871         }
1872
1873 error:
1874         return -ENOSYS;
1875 }
1876
1877 #ifdef CONFIG_COMPAT
1878 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1879                 unsigned int cmd, unsigned long arg)
1880 {
1881         struct lib_ring_buffer *buf = filp->private_data;
1882         struct channel *chan = buf->backend.chan;
1883         const struct lib_ring_buffer_config *config = &chan->backend.config;
1884         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1885         int ret;
1886
1887         if (atomic_read(&chan->record_disabled))
1888                 return -EIO;
1889
1890         switch (cmd) {
1891         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1892         {
1893                 uint64_t ts;
1894
1895                 ret = ops->timestamp_begin(config, buf, &ts);
1896                 if (ret < 0)
1897                         goto error;
1898                 return put_u64(ts, arg);
1899         }
1900         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1901         {
1902                 uint64_t ts;
1903
1904                 ret = ops->timestamp_end(config, buf, &ts);
1905                 if (ret < 0)
1906                         goto error;
1907                 return put_u64(ts, arg);
1908         }
1909         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1910         {
1911                 uint64_t ed;
1912
1913                 ret = ops->events_discarded(config, buf, &ed);
1914                 if (ret < 0)
1915                         goto error;
1916                 return put_u64(ed, arg);
1917         }
1918         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1919         {
1920                 uint64_t cs;
1921
1922                 ret = ops->content_size(config, buf, &cs);
1923                 if (ret < 0)
1924                         goto error;
1925                 return put_u64(cs, arg);
1926         }
1927         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1928         {
1929                 uint64_t ps;
1930
1931                 ret = ops->packet_size(config, buf, &ps);
1932                 if (ret < 0)
1933                         goto error;
1934                 return put_u64(ps, arg);
1935         }
1936         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1937         {
1938                 uint64_t si;
1939
1940                 ret = ops->stream_id(config, buf, &si);
1941                 if (ret < 0)
1942                         goto error;
1943                 return put_u64(si, arg);
1944         }
1945         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1946         {
1947                 uint64_t ts;
1948
1949                 ret = ops->current_timestamp(config, buf, &ts);
1950                 if (ret < 0)
1951                         goto error;
1952                 return put_u64(ts, arg);
1953         }
1954         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1955         {
1956                 uint64_t seq;
1957
1958                 ret = ops->sequence_number(config, buf, &seq);
1959                 if (ret < 0)
1960                         goto error;
1961                 return put_u64(seq, arg);
1962         }
1963         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1964         {
1965                 uint64_t id;
1966
1967                 ret = ops->instance_id(config, buf, &id);
1968                 if (ret < 0)
1969                         goto error;
1970                 return put_u64(id, arg);
1971         }
1972         default:
1973                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1974                                 cmd, arg);
1975         }
1976
1977 error:
1978         return -ENOSYS;
1979 }
1980 #endif /* CONFIG_COMPAT */
1981
1982 static void lttng_stream_override_ring_buffer_fops(void)
1983 {
1984         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1985         lttng_stream_ring_buffer_file_operations.open =
1986                 lib_ring_buffer_file_operations.open;
1987         lttng_stream_ring_buffer_file_operations.release =
1988                 lib_ring_buffer_file_operations.release;
1989         lttng_stream_ring_buffer_file_operations.poll =
1990                 lib_ring_buffer_file_operations.poll;
1991         lttng_stream_ring_buffer_file_operations.splice_read =
1992                 lib_ring_buffer_file_operations.splice_read;
1993         lttng_stream_ring_buffer_file_operations.mmap =
1994                 lib_ring_buffer_file_operations.mmap;
1995         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1996                 lttng_stream_ring_buffer_ioctl;
1997         lttng_stream_ring_buffer_file_operations.llseek =
1998                 lib_ring_buffer_file_operations.llseek;
1999 #ifdef CONFIG_COMPAT
2000         lttng_stream_ring_buffer_file_operations.compat_ioctl =
2001                 lttng_stream_ring_buffer_compat_ioctl;
2002 #endif
2003 }
2004
2005 int __init lttng_abi_init(void)
2006 {
2007         int ret = 0;
2008
2009         wrapper_vmalloc_sync_mappings();
2010         lttng_clock_ref();
2011
2012         ret = lttng_tp_mempool_init();
2013         if (ret) {
2014                 goto error;
2015         }
2016
2017         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
2018                                         &lttng_proc_ops, NULL);
2019
2020         if (!lttng_proc_dentry) {
2021                 printk(KERN_ERR "LTTng: Error creating control file\n");
2022                 ret = -ENOMEM;
2023                 goto error;
2024         }
2025         lttng_stream_override_ring_buffer_fops();
2026         return 0;
2027
2028 error:
2029         lttng_tp_mempool_destroy();
2030         lttng_clock_unref();
2031         return ret;
2032 }
2033
2034 /* No __exit annotation because used by init error path too. */
2035 void lttng_abi_exit(void)
2036 {
2037         lttng_tp_mempool_destroy();
2038         lttng_clock_unref();
2039         if (lttng_proc_dentry)
2040                 remove_proc_entry("lttng", NULL);
2041 }