lttng-abi.c

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