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