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