lttng-abi.c

   1 /*
   2  * lttng-abi.c
   3  *
   4  * LTTng ABI
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  *
  23  * Mimic system calls for:
  24  * - session creation, returns a file descriptor or failure.
  25  *   - channel creation, returns a file descriptor or failure.
  26  *     - Operates on a session file descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns a file descriptor or failure.
  29  *     - Operates on a channel file descriptor.
  30  *   - stream notifier get, returns a file descriptor or failure.
  31  *     - Operates on a channel file descriptor.
  32  *   - event creation, returns a file descriptor or failure.
  33  *     - Operates on a channel file descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/anon_inodes.h>
  43 #include <linux/file.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/slab.h>
  46 #include <linux/err.h>
  47 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  48 #include "wrapper/ringbuffer/vfs.h"
  49 #include "wrapper/ringbuffer/backend.h"
  50 #include "wrapper/ringbuffer/frontend.h"
  51 #include "wrapper/poll.h"
  52 #include "wrapper/file.h"
  53 #include "wrapper/kref.h"
  54 #include "lttng-abi.h"
  55 #include "lttng-abi-old.h"
  56 #include "lttng-events.h"
  57 #include "lttng-tracer.h"
  58 #include "lib/ringbuffer/frontend_types.h"
  59
  60 /*
  61  * This is LTTng's own personal way to create a system call as an external
  62  * module. We use ioctl() on /proc/lttng.
  63  */
  64
  65 static struct proc_dir_entry *lttng_proc_dentry;
  66 static const struct file_operations lttng_fops;
  67 static const struct file_operations lttng_session_fops;
  68 static const struct file_operations lttng_channel_fops;
  69 static const struct file_operations lttng_metadata_fops;
  70 static const struct file_operations lttng_event_fops;
  71 static struct file_operations lttng_stream_ring_buffer_file_operations;
  72
  73 /*
  74  * Teardown management: opened file descriptors keep a refcount on the module,
  75  * so it can only exit when all file descriptors are closed.
  76  */
  77
  78 static
  79 int lttng_abi_create_session(void)
  80 {
  81         struct lttng_session *session;
  82         struct file *session_file;
  83         int session_fd, ret;
  84
  85         session = lttng_session_create();
  86         if (!session)
  87                 return -ENOMEM;
  88         session_fd = lttng_get_unused_fd();
  89         if (session_fd < 0) {
  90                 ret = session_fd;
  91                 goto fd_error;
  92         }
  93         session_file = anon_inode_getfile("[lttng_session]",
  94                                           &lttng_session_fops,
  95                                           session, O_RDWR);
  96         if (IS_ERR(session_file)) {
  97                 ret = PTR_ERR(session_file);
  98                 goto file_error;
  99         }
 100         session->file = session_file;
 101         fd_install(session_fd, session_file);
 102         return session_fd;
 103
 104 file_error:
 105         put_unused_fd(session_fd);
 106 fd_error:
 107         lttng_session_destroy(session);
 108         return ret;
 109 }
 110
 111 static
 112 int lttng_abi_tracepoint_list(void)
 113 {
 114         struct file *tracepoint_list_file;
 115         int file_fd, ret;
 116
 117         file_fd = lttng_get_unused_fd();
 118         if (file_fd < 0) {
 119                 ret = file_fd;
 120                 goto fd_error;
 121         }
 122
 123         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 124                                           &lttng_tracepoint_list_fops,
 125                                           NULL, O_RDWR);
 126         if (IS_ERR(tracepoint_list_file)) {
 127                 ret = PTR_ERR(tracepoint_list_file);
 128                 goto file_error;
 129         }
 130         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 131         if (ret < 0)
 132                 goto open_error;
 133         fd_install(file_fd, tracepoint_list_file);
 134         return file_fd;
 135
 136 open_error:
 137         fput(tracepoint_list_file);
 138 file_error:
 139         put_unused_fd(file_fd);
 140 fd_error:
 141         return ret;
 142 }
 143
 144 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 145 static inline
 146 int lttng_abi_syscall_list(void)
 147 {
 148         return -ENOSYS;
 149 }
 150 #else
 151 static
 152 int lttng_abi_syscall_list(void)
 153 {
 154         struct file *syscall_list_file;
 155         int file_fd, ret;
 156
 157         file_fd = lttng_get_unused_fd();
 158         if (file_fd < 0) {
 159                 ret = file_fd;
 160                 goto fd_error;
 161         }
 162
 163         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 164                                           &lttng_syscall_list_fops,
 165                                           NULL, O_RDWR);
 166         if (IS_ERR(syscall_list_file)) {
 167                 ret = PTR_ERR(syscall_list_file);
 168                 goto file_error;
 169         }
 170         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 171         if (ret < 0)
 172                 goto open_error;
 173         fd_install(file_fd, syscall_list_file);
 174         return file_fd;
 175
 176 open_error:
 177         fput(syscall_list_file);
 178 file_error:
 179         put_unused_fd(file_fd);
 180 fd_error:
 181         return ret;
 182 }
 183 #endif
 184
 185 static
 186 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 187 {
 188         v->major = LTTNG_MODULES_MAJOR_VERSION;
 189         v->minor = LTTNG_MODULES_MINOR_VERSION;
 190         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 191 }
 192
 193 static
 194 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 195 {
 196         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 197         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 198 }
 199
 200 static
 201 long lttng_abi_add_context(struct file *file,
 202         struct lttng_kernel_context *context_param,
 203         struct lttng_ctx **ctx, struct lttng_session *session)
 204 {
 205
 206         if (session->been_active)
 207                 return -EPERM;
 208
 209         switch (context_param->ctx) {
 210         case LTTNG_KERNEL_CONTEXT_PID:
 211                 return lttng_add_pid_to_ctx(ctx);
 212         case LTTNG_KERNEL_CONTEXT_PRIO:
 213                 return lttng_add_prio_to_ctx(ctx);
 214         case LTTNG_KERNEL_CONTEXT_NICE:
 215                 return lttng_add_nice_to_ctx(ctx);
 216         case LTTNG_KERNEL_CONTEXT_VPID:
 217                 return lttng_add_vpid_to_ctx(ctx);
 218         case LTTNG_KERNEL_CONTEXT_TID:
 219                 return lttng_add_tid_to_ctx(ctx);
 220         case LTTNG_KERNEL_CONTEXT_VTID:
 221                 return lttng_add_vtid_to_ctx(ctx);
 222         case LTTNG_KERNEL_CONTEXT_PPID:
 223                 return lttng_add_ppid_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_VPPID:
 225                 return lttng_add_vppid_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 227                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 228                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 229                                 context_param->u.perf_counter.config,
 230                                 context_param->u.perf_counter.name,
 231                                 ctx);
 232         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 233                 return lttng_add_procname_to_ctx(ctx);
 234         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 235                 return lttng_add_hostname_to_ctx(ctx);
 236         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 237                 return lttng_add_cpu_id_to_ctx(ctx);
 238         default:
 239                 return -EINVAL;
 240         }
 241 }
 242
 243 /**
 244  *      lttng_ioctl - lttng syscall through ioctl
 245  *
 246  *      @file: the file
 247  *      @cmd: the command
 248  *      @arg: command arg
 249  *
 250  *      This ioctl implements lttng commands:
 251  *      LTTNG_KERNEL_SESSION
 252  *              Returns a LTTng trace session file descriptor
 253  *      LTTNG_KERNEL_TRACER_VERSION
 254  *              Returns the LTTng kernel tracer version
 255  *      LTTNG_KERNEL_TRACEPOINT_LIST
 256  *              Returns a file descriptor listing available tracepoints
 257  *      LTTNG_KERNEL_WAIT_QUIESCENT
 258  *              Returns after all previously running probes have completed
 259  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 260  *              Returns the LTTng kernel tracer ABI version
 261  *
 262  * The returned session will be deleted when its file descriptor is closed.
 263  */
 264 static
 265 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 266 {
 267         switch (cmd) {
 268         case LTTNG_KERNEL_OLD_SESSION:
 269         case LTTNG_KERNEL_SESSION:
 270                 return lttng_abi_create_session();
 271         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 272         {
 273                 struct lttng_kernel_tracer_version v;
 274                 struct lttng_kernel_old_tracer_version oldv;
 275                 struct lttng_kernel_old_tracer_version *uversion =
 276                         (struct lttng_kernel_old_tracer_version __user *) arg;
 277
 278                 lttng_abi_tracer_version(&v);
 279                 oldv.major = v.major;
 280                 oldv.minor = v.minor;
 281                 oldv.patchlevel = v.patchlevel;
 282
 283                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 284                         return -EFAULT;
 285                 return 0;
 286         }
 287         case LTTNG_KERNEL_TRACER_VERSION:
 288         {
 289                 struct lttng_kernel_tracer_version version;
 290                 struct lttng_kernel_tracer_version *uversion =
 291                         (struct lttng_kernel_tracer_version __user *) arg;
 292
 293                 lttng_abi_tracer_version(&version);
 294
 295                 if (copy_to_user(uversion, &version, sizeof(version)))
 296                         return -EFAULT;
 297                 return 0;
 298         }
 299         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 300         {
 301                 struct lttng_kernel_tracer_abi_version version;
 302                 struct lttng_kernel_tracer_abi_version *uversion =
 303                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 304
 305                 lttng_abi_tracer_abi_version(&version);
 306
 307                 if (copy_to_user(uversion, &version, sizeof(version)))
 308                         return -EFAULT;
 309                 return 0;
 310         }
 311         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 312         case LTTNG_KERNEL_TRACEPOINT_LIST:
 313                 return lttng_abi_tracepoint_list();
 314         case LTTNG_KERNEL_SYSCALL_LIST:
 315                 return lttng_abi_syscall_list();
 316         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 317         case LTTNG_KERNEL_WAIT_QUIESCENT:
 318                 synchronize_trace();
 319                 return 0;
 320         case LTTNG_KERNEL_OLD_CALIBRATE:
 321         {
 322                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 323                         (struct lttng_kernel_old_calibrate __user *) arg;
 324                 struct lttng_kernel_old_calibrate old_calibrate;
 325                 struct lttng_kernel_calibrate calibrate;
 326                 int ret;
 327
 328                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 329                         return -EFAULT;
 330                 calibrate.type = old_calibrate.type;
 331                 ret = lttng_calibrate(&calibrate);
 332                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 333                         return -EFAULT;
 334                 return ret;
 335         }
 336         case LTTNG_KERNEL_CALIBRATE:
 337         {
 338                 struct lttng_kernel_calibrate __user *ucalibrate =
 339                         (struct lttng_kernel_calibrate __user *) arg;
 340                 struct lttng_kernel_calibrate calibrate;
 341                 int ret;
 342
 343                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 344                         return -EFAULT;
 345                 ret = lttng_calibrate(&calibrate);
 346                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 347                         return -EFAULT;
 348                 return ret;
 349         }
 350         default:
 351                 return -ENOIOCTLCMD;
 352         }
 353 }
 354
 355 static const struct file_operations lttng_fops = {
 356         .owner = THIS_MODULE,
 357         .unlocked_ioctl = lttng_ioctl,
 358 #ifdef CONFIG_COMPAT
 359         .compat_ioctl = lttng_ioctl,
 360 #endif
 361 };
 362
 363 static
 364 int lttng_abi_create_channel(struct file *session_file,
 365                              struct lttng_kernel_channel *chan_param,
 366                              enum channel_type channel_type)
 367 {
 368         struct lttng_session *session = session_file->private_data;
 369         const struct file_operations *fops = NULL;
 370         const char *transport_name;
 371         struct lttng_channel *chan;
 372         struct file *chan_file;
 373         int chan_fd;
 374         int ret = 0;
 375
 376         chan_fd = lttng_get_unused_fd();
 377         if (chan_fd < 0) {
 378                 ret = chan_fd;
 379                 goto fd_error;
 380         }
 381         switch (channel_type) {
 382         case PER_CPU_CHANNEL:
 383                 fops = &lttng_channel_fops;
 384                 break;
 385         case METADATA_CHANNEL:
 386                 fops = &lttng_metadata_fops;
 387                 break;
 388         }
 389
 390         chan_file = anon_inode_getfile("[lttng_channel]",
 391                                        fops,
 392                                        NULL, O_RDWR);
 393         if (IS_ERR(chan_file)) {
 394                 ret = PTR_ERR(chan_file);
 395                 goto file_error;
 396         }
 397         switch (channel_type) {
 398         case PER_CPU_CHANNEL:
 399                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 400                         transport_name = chan_param->overwrite ?
 401                                 "relay-overwrite" : "relay-discard";
 402                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 403                         transport_name = chan_param->overwrite ?
 404                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 405                 } else {
 406                         return -EINVAL;
 407                 }
 408                 break;
 409         case METADATA_CHANNEL:
 410                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 411                         transport_name = "relay-metadata";
 412                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 413                         transport_name = "relay-metadata-mmap";
 414                 else
 415                         return -EINVAL;
 416                 break;
 417         default:
 418                 transport_name = "<unknown>";
 419                 break;
 420         }
 421         if (atomic_long_add_unless(&session_file->f_count,
 422                 1, INT_MAX) == INT_MAX) {
 423                 goto refcount_error;
 424         }
 425         /*
 426          * We tolerate no failure path after channel creation. It will stay
 427          * invariant for the rest of the session.
 428          */
 429         chan = lttng_channel_create(session, transport_name, NULL,
 430                                   chan_param->subbuf_size,
 431                                   chan_param->num_subbuf,
 432                                   chan_param->switch_timer_interval,
 433                                   chan_param->read_timer_interval,
 434                                   channel_type);
 435         if (!chan) {
 436                 ret = -EINVAL;
 437                 goto chan_error;
 438         }
 439         chan->file = chan_file;
 440         chan_file->private_data = chan;
 441         fd_install(chan_fd, chan_file);
 442
 443         return chan_fd;
 444
 445 chan_error:
 446         atomic_long_dec(&session_file->f_count);
 447 refcount_error:
 448         fput(chan_file);
 449 file_error:
 450         put_unused_fd(chan_fd);
 451 fd_error:
 452         return ret;
 453 }
 454
 455 /**
 456  *      lttng_session_ioctl - lttng session fd ioctl
 457  *
 458  *      @file: the file
 459  *      @cmd: the command
 460  *      @arg: command arg
 461  *
 462  *      This ioctl implements lttng commands:
 463  *      LTTNG_KERNEL_CHANNEL
 464  *              Returns a LTTng channel file descriptor
 465  *      LTTNG_KERNEL_ENABLE
 466  *              Enables tracing for a session (weak enable)
 467  *      LTTNG_KERNEL_DISABLE
 468  *              Disables tracing for a session (strong disable)
 469  *      LTTNG_KERNEL_METADATA
 470  *              Returns a LTTng metadata file descriptor
 471  *      LTTNG_KERNEL_SESSION_TRACK_PID
 472  *              Add PID to session tracker
 473  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 474  *              Remove PID from session tracker
 475  *
 476  * The returned channel will be deleted when its file descriptor is closed.
 477  */
 478 static
 479 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 480 {
 481         struct lttng_session *session = file->private_data;
 482
 483         switch (cmd) {
 484         case LTTNG_KERNEL_OLD_CHANNEL:
 485         {
 486                 struct lttng_kernel_channel chan_param;
 487                 struct lttng_kernel_old_channel old_chan_param;
 488
 489                 if (copy_from_user(&old_chan_param,
 490                                 (struct lttng_kernel_old_channel __user *) arg,
 491                                 sizeof(struct lttng_kernel_old_channel)))
 492                         return -EFAULT;
 493                 chan_param.overwrite = old_chan_param.overwrite;
 494                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 495                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 496                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 497                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 498                 chan_param.output = old_chan_param.output;
 499
 500                 return lttng_abi_create_channel(file, &chan_param,
 501                                 PER_CPU_CHANNEL);
 502         }
 503         case LTTNG_KERNEL_CHANNEL:
 504         {
 505                 struct lttng_kernel_channel chan_param;
 506
 507                 if (copy_from_user(&chan_param,
 508                                 (struct lttng_kernel_channel __user *) arg,
 509                                 sizeof(struct lttng_kernel_channel)))
 510                         return -EFAULT;
 511                 return lttng_abi_create_channel(file, &chan_param,
 512                                 PER_CPU_CHANNEL);
 513         }
 514         case LTTNG_KERNEL_OLD_SESSION_START:
 515         case LTTNG_KERNEL_OLD_ENABLE:
 516         case LTTNG_KERNEL_SESSION_START:
 517         case LTTNG_KERNEL_ENABLE:
 518                 return lttng_session_enable(session);
 519         case LTTNG_KERNEL_OLD_SESSION_STOP:
 520         case LTTNG_KERNEL_OLD_DISABLE:
 521         case LTTNG_KERNEL_SESSION_STOP:
 522         case LTTNG_KERNEL_DISABLE:
 523                 return lttng_session_disable(session);
 524         case LTTNG_KERNEL_OLD_METADATA:
 525         {
 526                 struct lttng_kernel_channel chan_param;
 527                 struct lttng_kernel_old_channel old_chan_param;
 528
 529                 if (copy_from_user(&old_chan_param,
 530                                 (struct lttng_kernel_old_channel __user *) arg,
 531                                 sizeof(struct lttng_kernel_old_channel)))
 532                         return -EFAULT;
 533                 chan_param.overwrite = old_chan_param.overwrite;
 534                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 535                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 536                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 537                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 538                 chan_param.output = old_chan_param.output;
 539
 540                 return lttng_abi_create_channel(file, &chan_param,
 541                                 METADATA_CHANNEL);
 542         }
 543         case LTTNG_KERNEL_METADATA:
 544         {
 545                 struct lttng_kernel_channel chan_param;
 546
 547                 if (copy_from_user(&chan_param,
 548                                         (struct lttng_kernel_channel __user *) arg,
 549                                         sizeof(struct lttng_kernel_channel)))
 550                         return -EFAULT;
 551                 return lttng_abi_create_channel(file, &chan_param,
 552                                 METADATA_CHANNEL);
 553         }
 554         case LTTNG_KERNEL_SESSION_TRACK_PID:
 555                 return lttng_session_track_pid(session, (int) arg);
 556         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 557                 return lttng_session_untrack_pid(session, (int) arg);
 558         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 559                 return lttng_session_list_tracker_pids(session);
 560         default:
 561                 return -ENOIOCTLCMD;
 562         }
 563 }
 564
 565 /*
 566  * Called when the last file reference is dropped.
 567  *
 568  * Big fat note: channels and events are invariant for the whole session after
 569  * their creation. So this session destruction also destroys all channel and
 570  * event structures specific to this session (they are not destroyed when their
 571  * individual file is released).
 572  */
 573 static
 574 int lttng_session_release(struct inode *inode, struct file *file)
 575 {
 576         struct lttng_session *session = file->private_data;
 577
 578         if (session)
 579                 lttng_session_destroy(session);
 580         return 0;
 581 }
 582
 583 static const struct file_operations lttng_session_fops = {
 584         .owner = THIS_MODULE,
 585         .release = lttng_session_release,
 586         .unlocked_ioctl = lttng_session_ioctl,
 587 #ifdef CONFIG_COMPAT
 588         .compat_ioctl = lttng_session_ioctl,
 589 #endif
 590 };
 591
 592 /**
 593  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 594  *      @filp: the file
 595  *      @wait: poll table
 596  *
 597  *      Handles the poll operations for the metadata channels.
 598  */
 599 static
 600 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 601                 poll_table *wait)
 602 {
 603         struct lttng_metadata_stream *stream = filp->private_data;
 604         struct lib_ring_buffer *buf = stream->priv;
 605         int finalized;
 606         unsigned int mask = 0;
 607
 608         if (filp->f_mode & FMODE_READ) {
 609                 poll_wait_set_exclusive(wait);
 610                 poll_wait(filp, &stream->read_wait, wait);
 611
 612                 finalized = stream->finalized;
 613
 614                 /*
 615                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 616                  * ordering finalized load before offsets loads.
 617                  */
 618                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 619
 620                 if (finalized)
 621                         mask |= POLLHUP;
 622
 623                 mutex_lock(&stream->metadata_cache->lock);
 624                 if (stream->metadata_cache->metadata_written >
 625                                 stream->metadata_out)
 626                         mask |= POLLIN;
 627                 mutex_unlock(&stream->metadata_cache->lock);
 628         }
 629
 630         return mask;
 631 }
 632
 633 static
 634 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 635                 unsigned int cmd, unsigned long arg)
 636 {
 637         struct lttng_metadata_stream *stream = filp->private_data;
 638
 639         stream->metadata_out = stream->metadata_in;
 640 }
 641
 642 static
 643 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 644                 unsigned int cmd, unsigned long arg)
 645 {
 646         int ret;
 647         struct lttng_metadata_stream *stream = filp->private_data;
 648         struct lib_ring_buffer *buf = stream->priv;
 649
 650         switch (cmd) {
 651         case RING_BUFFER_GET_NEXT_SUBBUF:
 652         {
 653                 struct lttng_metadata_stream *stream = filp->private_data;
 654                 struct lib_ring_buffer *buf = stream->priv;
 655                 struct channel *chan = buf->backend.chan;
 656
 657                 ret = lttng_metadata_output_channel(stream, chan);
 658                 if (ret > 0) {
 659                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 660                         ret = 0;
 661                 } else if (ret < 0)
 662                         goto err;
 663                 break;
 664         }
 665         case RING_BUFFER_GET_SUBBUF:
 666         {
 667                 /*
 668                  * Random access is not allowed for metadata channel.
 669                  */
 670                 return -ENOSYS;
 671         }
 672         case RING_BUFFER_FLUSH:
 673         {
 674                 struct lttng_metadata_stream *stream = filp->private_data;
 675                 struct lib_ring_buffer *buf = stream->priv;
 676                 struct channel *chan = buf->backend.chan;
 677
 678                 /*
 679                  * Before doing the actual ring buffer flush, write up to one
 680                  * packet of metadata in the ring buffer.
 681                  */
 682                 ret = lttng_metadata_output_channel(stream, chan);
 683                 if (ret < 0)
 684                         goto err;
 685                 break;
 686         }
 687         default:
 688                 break;
 689         }
 690         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 691
 692         /* Performing lib ring buffer ioctl after our own. */
 693         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 694         if (ret < 0)
 695                 goto err;
 696
 697         switch (cmd) {
 698         case RING_BUFFER_PUT_NEXT_SUBBUF:
 699         {
 700                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 701                                 cmd, arg);
 702                 break;
 703         }
 704         default:
 705                 break;
 706         }
 707 err:
 708         return ret;
 709 }
 710
 711 #ifdef CONFIG_COMPAT
 712 static
 713 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 714                 unsigned int cmd, unsigned long arg)
 715 {
 716         int ret;
 717         struct lttng_metadata_stream *stream = filp->private_data;
 718         struct lib_ring_buffer *buf = stream->priv;
 719
 720         switch (cmd) {
 721         case RING_BUFFER_GET_NEXT_SUBBUF:
 722         {
 723                 struct lttng_metadata_stream *stream = filp->private_data;
 724                 struct lib_ring_buffer *buf = stream->priv;
 725                 struct channel *chan = buf->backend.chan;
 726
 727                 ret = lttng_metadata_output_channel(stream, chan);
 728                 if (ret > 0) {
 729                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 730                         ret = 0;
 731                 } else if (ret < 0)
 732                         goto err;
 733                 break;
 734         }
 735         case RING_BUFFER_GET_SUBBUF:
 736         {
 737                 /*
 738                  * Random access is not allowed for metadata channel.
 739                  */
 740                 return -ENOSYS;
 741         }
 742         default:
 743                 break;
 744         }
 745         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 746
 747         /* Performing lib ring buffer ioctl after our own. */
 748         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 749         if (ret < 0)
 750                 goto err;
 751
 752         switch (cmd) {
 753         case RING_BUFFER_PUT_NEXT_SUBBUF:
 754         {
 755                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 756                                 cmd, arg);
 757                 break;
 758         }
 759         default:
 760                 break;
 761         }
 762 err:
 763         return ret;
 764 }
 765 #endif
 766
 767 /*
 768  * This is not used by anonymous file descriptors. This code is left
 769  * there if we ever want to implement an inode with open() operation.
 770  */
 771 static
 772 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 773 {
 774         struct lttng_metadata_stream *stream = inode->i_private;
 775         struct lib_ring_buffer *buf = stream->priv;
 776
 777         file->private_data = buf;
 778         /*
 779          * Since life-time of metadata cache differs from that of
 780          * session, we need to keep our own reference on the transport.
 781          */
 782         if (!try_module_get(stream->transport->owner)) {
 783                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 784                 return -EBUSY;
 785         }
 786         return lib_ring_buffer_open(inode, file, buf);
 787 }
 788
 789 static
 790 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 791 {
 792         struct lttng_metadata_stream *stream = file->private_data;
 793         struct lib_ring_buffer *buf = stream->priv;
 794
 795         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 796         module_put(stream->transport->owner);
 797         return lib_ring_buffer_release(inode, file, buf);
 798 }
 799
 800 static
 801 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 802                 struct pipe_inode_info *pipe, size_t len,
 803                 unsigned int flags)
 804 {
 805         struct lttng_metadata_stream *stream = in->private_data;
 806         struct lib_ring_buffer *buf = stream->priv;
 807
 808         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 809                         flags, buf);
 810 }
 811
 812 static
 813 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 814                 struct vm_area_struct *vma)
 815 {
 816         struct lttng_metadata_stream *stream = filp->private_data;
 817         struct lib_ring_buffer *buf = stream->priv;
 818
 819         return lib_ring_buffer_mmap(filp, vma, buf);
 820 }
 821
 822 static
 823 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 824         .owner = THIS_MODULE,
 825         .open = lttng_metadata_ring_buffer_open,
 826         .release = lttng_metadata_ring_buffer_release,
 827         .poll = lttng_metadata_ring_buffer_poll,
 828         .splice_read = lttng_metadata_ring_buffer_splice_read,
 829         .mmap = lttng_metadata_ring_buffer_mmap,
 830         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 831         .llseek = vfs_lib_ring_buffer_no_llseek,
 832 #ifdef CONFIG_COMPAT
 833         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 834 #endif
 835 };
 836
 837 static
 838 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 839                 const struct file_operations *fops)
 840 {
 841         int stream_fd, ret;
 842         struct file *stream_file;
 843
 844         stream_fd = lttng_get_unused_fd();
 845         if (stream_fd < 0) {
 846                 ret = stream_fd;
 847                 goto fd_error;
 848         }
 849         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 850                         stream_priv, O_RDWR);
 851         if (IS_ERR(stream_file)) {
 852                 ret = PTR_ERR(stream_file);
 853                 goto file_error;
 854         }
 855         /*
 856          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 857          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 858          * file descriptor, so we set FMODE_PREAD here.
 859          */
 860         stream_file->f_mode |= FMODE_PREAD;
 861         fd_install(stream_fd, stream_file);
 862         /*
 863          * The stream holds a reference to the channel within the generic ring
 864          * buffer library, so no need to hold a refcount on the channel and
 865          * session files here.
 866          */
 867         return stream_fd;
 868
 869 file_error:
 870         put_unused_fd(stream_fd);
 871 fd_error:
 872         return ret;
 873 }
 874
 875 static
 876 int lttng_abi_open_stream(struct file *channel_file)
 877 {
 878         struct lttng_channel *channel = channel_file->private_data;
 879         struct lib_ring_buffer *buf;
 880         int ret;
 881         void *stream_priv;
 882
 883         buf = channel->ops->buffer_read_open(channel->chan);
 884         if (!buf)
 885                 return -ENOENT;
 886
 887         stream_priv = buf;
 888         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 889                         &lttng_stream_ring_buffer_file_operations);
 890         if (ret < 0)
 891                 goto fd_error;
 892
 893         return ret;
 894
 895 fd_error:
 896         channel->ops->buffer_read_close(buf);
 897         return ret;
 898 }
 899
 900 static
 901 int lttng_abi_open_metadata_stream(struct file *channel_file)
 902 {
 903         struct lttng_channel *channel = channel_file->private_data;
 904         struct lttng_session *session = channel->session;
 905         struct lib_ring_buffer *buf;
 906         int ret;
 907         struct lttng_metadata_stream *metadata_stream;
 908         void *stream_priv;
 909
 910         buf = channel->ops->buffer_read_open(channel->chan);
 911         if (!buf)
 912                 return -ENOENT;
 913
 914         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 915                         GFP_KERNEL);
 916         if (!metadata_stream) {
 917                 ret = -ENOMEM;
 918                 goto nomem;
 919         }
 920         metadata_stream->metadata_cache = session->metadata_cache;
 921         init_waitqueue_head(&metadata_stream->read_wait);
 922         metadata_stream->priv = buf;
 923         stream_priv = metadata_stream;
 924         metadata_stream->transport = channel->transport;
 925
 926         /*
 927          * Since life-time of metadata cache differs from that of
 928          * session, we need to keep our own reference on the transport.
 929          */
 930         if (!try_module_get(metadata_stream->transport->owner)) {
 931                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 932                 ret = -EINVAL;
 933                 goto notransport;
 934         }
 935
 936         if (!lttng_kref_get(&session->metadata_cache->refcount))
 937                 goto kref_error;
 938         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 939                         &lttng_metadata_ring_buffer_file_operations);
 940         if (ret < 0)
 941                 goto fd_error;
 942
 943         list_add(&metadata_stream->list,
 944                 &session->metadata_cache->metadata_stream);
 945         return ret;
 946
 947 fd_error:
 948         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 949 kref_error:
 950         module_put(metadata_stream->transport->owner);
 951 notransport:
 952         kfree(metadata_stream);
 953 nomem:
 954         channel->ops->buffer_read_close(buf);
 955         return ret;
 956 }
 957
 958 static
 959 int lttng_abi_create_event(struct file *channel_file,
 960                            struct lttng_kernel_event *event_param)
 961 {
 962         struct lttng_channel *channel = channel_file->private_data;
 963         int event_fd, ret;
 964         struct file *event_file;
 965         void *priv;
 966
 967         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 968         switch (event_param->instrumentation) {
 969         case LTTNG_KERNEL_KRETPROBE:
 970                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 971                 break;
 972         case LTTNG_KERNEL_KPROBE:
 973                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 974                 break;
 975         case LTTNG_KERNEL_FUNCTION:
 976                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 977                 break;
 978         default:
 979                 break;
 980         }
 981         event_fd = lttng_get_unused_fd();
 982         if (event_fd < 0) {
 983                 ret = event_fd;
 984                 goto fd_error;
 985         }
 986         event_file = anon_inode_getfile("[lttng_event]",
 987                                         &lttng_event_fops,
 988                                         NULL, O_RDWR);
 989         if (IS_ERR(event_file)) {
 990                 ret = PTR_ERR(event_file);
 991                 goto file_error;
 992         }
 993         /* The event holds a reference on the channel */
 994         if (atomic_long_add_unless(&channel_file->f_count,
 995                 1, INT_MAX) == INT_MAX) {
 996                 ret = -EOVERFLOW;
 997                 goto refcount_error;
 998         }
 999         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1000                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1001                 struct lttng_enabler *enabler;
1002
1003                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1004                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1005                                 event_param, channel);
1006                 } else {
1007                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1008                                 event_param, channel);
1009                 }
1010                 priv = enabler;
1011         } else {
1012                 struct lttng_event *event;
1013
1014                 /*
1015                  * We tolerate no failure path after event creation. It
1016                  * will stay invariant for the rest of the session.
1017                  */
1018                 event = lttng_event_create(channel, event_param,
1019                                 NULL, NULL,
1020                                 event_param->instrumentation);
1021                 WARN_ON_ONCE(!event);
1022                 if (IS_ERR(event)) {
1023                         ret = PTR_ERR(event);
1024                         goto event_error;
1025                 }
1026                 priv = event;
1027         }
1028         event_file->private_data = priv;
1029         fd_install(event_fd, event_file);
1030         return event_fd;
1031
1032 event_error:
1033         atomic_long_dec(&channel_file->f_count);
1034 refcount_error:
1035         fput(event_file);
1036 file_error:
1037         put_unused_fd(event_fd);
1038 fd_error:
1039         return ret;
1040 }
1041
1042 /**
1043  *      lttng_channel_ioctl - lttng syscall through ioctl
1044  *
1045  *      @file: the file
1046  *      @cmd: the command
1047  *      @arg: command arg
1048  *
1049  *      This ioctl implements lttng commands:
1050  *      LTTNG_KERNEL_STREAM
1051  *              Returns an event stream file descriptor or failure.
1052  *              (typically, one event stream records events from one CPU)
1053  *      LTTNG_KERNEL_EVENT
1054  *              Returns an event file descriptor or failure.
1055  *      LTTNG_KERNEL_CONTEXT
1056  *              Prepend a context field to each event in the channel
1057  *      LTTNG_KERNEL_ENABLE
1058  *              Enable recording for events in this channel (weak enable)
1059  *      LTTNG_KERNEL_DISABLE
1060  *              Disable recording for events in this channel (strong disable)
1061  *
1062  * Channel and event file descriptors also hold a reference on the session.
1063  */
1064 static
1065 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1066 {
1067         struct lttng_channel *channel = file->private_data;
1068
1069         switch (cmd) {
1070         case LTTNG_KERNEL_OLD_STREAM:
1071         case LTTNG_KERNEL_STREAM:
1072                 return lttng_abi_open_stream(file);
1073         case LTTNG_KERNEL_OLD_EVENT:
1074         {
1075                 struct lttng_kernel_event *uevent_param;
1076                 struct lttng_kernel_old_event *old_uevent_param;
1077                 int ret;
1078
1079                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1080                                 GFP_KERNEL);
1081                 if (!uevent_param) {
1082                         ret = -ENOMEM;
1083                         goto old_event_end;
1084                 }
1085                 old_uevent_param = kmalloc(
1086                                 sizeof(struct lttng_kernel_old_event),
1087                                 GFP_KERNEL);
1088                 if (!old_uevent_param) {
1089                         ret = -ENOMEM;
1090                         goto old_event_error_free_param;
1091                 }
1092                 if (copy_from_user(old_uevent_param,
1093                                 (struct lttng_kernel_old_event __user *) arg,
1094                                 sizeof(struct lttng_kernel_old_event))) {
1095                         ret = -EFAULT;
1096                         goto old_event_error_free_old_param;
1097                 }
1098
1099                 memcpy(uevent_param->name, old_uevent_param->name,
1100                                 sizeof(uevent_param->name));
1101                 uevent_param->instrumentation =
1102                         old_uevent_param->instrumentation;
1103
1104                 switch (old_uevent_param->instrumentation) {
1105                 case LTTNG_KERNEL_KPROBE:
1106                         uevent_param->u.kprobe.addr =
1107                                 old_uevent_param->u.kprobe.addr;
1108                         uevent_param->u.kprobe.offset =
1109                                 old_uevent_param->u.kprobe.offset;
1110                         memcpy(uevent_param->u.kprobe.symbol_name,
1111                                 old_uevent_param->u.kprobe.symbol_name,
1112                                 sizeof(uevent_param->u.kprobe.symbol_name));
1113                         break;
1114                 case LTTNG_KERNEL_KRETPROBE:
1115                         uevent_param->u.kretprobe.addr =
1116                                 old_uevent_param->u.kretprobe.addr;
1117                         uevent_param->u.kretprobe.offset =
1118                                 old_uevent_param->u.kretprobe.offset;
1119                         memcpy(uevent_param->u.kretprobe.symbol_name,
1120                                 old_uevent_param->u.kretprobe.symbol_name,
1121                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1122                         break;
1123                 case LTTNG_KERNEL_FUNCTION:
1124                         memcpy(uevent_param->u.ftrace.symbol_name,
1125                                         old_uevent_param->u.ftrace.symbol_name,
1126                                         sizeof(uevent_param->u.ftrace.symbol_name));
1127                         break;
1128                 default:
1129                         break;
1130                 }
1131                 ret = lttng_abi_create_event(file, uevent_param);
1132
1133 old_event_error_free_old_param:
1134                 kfree(old_uevent_param);
1135 old_event_error_free_param:
1136                 kfree(uevent_param);
1137 old_event_end:
1138                 return ret;
1139         }
1140         case LTTNG_KERNEL_EVENT:
1141         {
1142                 struct lttng_kernel_event uevent_param;
1143
1144                 if (copy_from_user(&uevent_param,
1145                                 (struct lttng_kernel_event __user *) arg,
1146                                 sizeof(uevent_param)))
1147                         return -EFAULT;
1148                 return lttng_abi_create_event(file, &uevent_param);
1149         }
1150         case LTTNG_KERNEL_OLD_CONTEXT:
1151         {
1152                 struct lttng_kernel_context *ucontext_param;
1153                 struct lttng_kernel_old_context *old_ucontext_param;
1154                 int ret;
1155
1156                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1157                                 GFP_KERNEL);
1158                 if (!ucontext_param) {
1159                         ret = -ENOMEM;
1160                         goto old_ctx_end;
1161                 }
1162                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1163                                 GFP_KERNEL);
1164                 if (!old_ucontext_param) {
1165                         ret = -ENOMEM;
1166                         goto old_ctx_error_free_param;
1167                 }
1168
1169                 if (copy_from_user(old_ucontext_param,
1170                                 (struct lttng_kernel_old_context __user *) arg,
1171                                 sizeof(struct lttng_kernel_old_context))) {
1172                         ret = -EFAULT;
1173                         goto old_ctx_error_free_old_param;
1174                 }
1175                 ucontext_param->ctx = old_ucontext_param->ctx;
1176                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1177                                 sizeof(ucontext_param->padding));
1178                 /* only type that uses the union */
1179                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1180                         ucontext_param->u.perf_counter.type =
1181                                 old_ucontext_param->u.perf_counter.type;
1182                         ucontext_param->u.perf_counter.config =
1183                                 old_ucontext_param->u.perf_counter.config;
1184                         memcpy(ucontext_param->u.perf_counter.name,
1185                                 old_ucontext_param->u.perf_counter.name,
1186                                 sizeof(ucontext_param->u.perf_counter.name));
1187                 }
1188
1189                 ret = lttng_abi_add_context(file,
1190                                 ucontext_param,
1191                                 &channel->ctx, channel->session);
1192
1193 old_ctx_error_free_old_param:
1194                 kfree(old_ucontext_param);
1195 old_ctx_error_free_param:
1196                 kfree(ucontext_param);
1197 old_ctx_end:
1198                 return ret;
1199         }
1200         case LTTNG_KERNEL_CONTEXT:
1201         {
1202                 struct lttng_kernel_context ucontext_param;
1203
1204                 if (copy_from_user(&ucontext_param,
1205                                 (struct lttng_kernel_context __user *) arg,
1206                                 sizeof(ucontext_param)))
1207                         return -EFAULT;
1208                 return lttng_abi_add_context(file,
1209                                 &ucontext_param,
1210                                 &channel->ctx, channel->session);
1211         }
1212         case LTTNG_KERNEL_OLD_ENABLE:
1213         case LTTNG_KERNEL_ENABLE:
1214                 return lttng_channel_enable(channel);
1215         case LTTNG_KERNEL_OLD_DISABLE:
1216         case LTTNG_KERNEL_DISABLE:
1217                 return lttng_channel_disable(channel);
1218         case LTTNG_KERNEL_SYSCALL_MASK:
1219                 return lttng_channel_syscall_mask(channel,
1220                         (struct lttng_kernel_syscall_mask __user *) arg);
1221         default:
1222                 return -ENOIOCTLCMD;
1223         }
1224
1225 }
1226
1227 /**
1228  *      lttng_metadata_ioctl - lttng syscall through ioctl
1229  *
1230  *      @file: the file
1231  *      @cmd: the command
1232  *      @arg: command arg
1233  *
1234  *      This ioctl implements lttng commands:
1235  *      LTTNG_KERNEL_STREAM
1236  *              Returns an event stream file descriptor or failure.
1237  *
1238  * Channel and event file descriptors also hold a reference on the session.
1239  */
1240 static
1241 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1242 {
1243         switch (cmd) {
1244         case LTTNG_KERNEL_OLD_STREAM:
1245         case LTTNG_KERNEL_STREAM:
1246                 return lttng_abi_open_metadata_stream(file);
1247         default:
1248                 return -ENOIOCTLCMD;
1249         }
1250 }
1251
1252 /**
1253  *      lttng_channel_poll - lttng stream addition/removal monitoring
1254  *
1255  *      @file: the file
1256  *      @wait: poll table
1257  */
1258 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1259 {
1260         struct lttng_channel *channel = file->private_data;
1261         unsigned int mask = 0;
1262
1263         if (file->f_mode & FMODE_READ) {
1264                 poll_wait_set_exclusive(wait);
1265                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1266                           wait);
1267
1268                 if (channel->ops->is_disabled(channel->chan))
1269                         return POLLERR;
1270                 if (channel->ops->is_finalized(channel->chan))
1271                         return POLLHUP;
1272                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1273                         return POLLIN | POLLRDNORM;
1274                 return 0;
1275         }
1276         return mask;
1277
1278 }
1279
1280 static
1281 int lttng_channel_release(struct inode *inode, struct file *file)
1282 {
1283         struct lttng_channel *channel = file->private_data;
1284
1285         if (channel)
1286                 fput(channel->session->file);
1287         return 0;
1288 }
1289
1290 static
1291 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1292 {
1293         struct lttng_channel *channel = file->private_data;
1294
1295         if (channel) {
1296                 fput(channel->session->file);
1297                 lttng_metadata_channel_destroy(channel);
1298         }
1299
1300         return 0;
1301 }
1302
1303 static const struct file_operations lttng_channel_fops = {
1304         .owner = THIS_MODULE,
1305         .release = lttng_channel_release,
1306         .poll = lttng_channel_poll,
1307         .unlocked_ioctl = lttng_channel_ioctl,
1308 #ifdef CONFIG_COMPAT
1309         .compat_ioctl = lttng_channel_ioctl,
1310 #endif
1311 };
1312
1313 static const struct file_operations lttng_metadata_fops = {
1314         .owner = THIS_MODULE,
1315         .release = lttng_metadata_channel_release,
1316         .unlocked_ioctl = lttng_metadata_ioctl,
1317 #ifdef CONFIG_COMPAT
1318         .compat_ioctl = lttng_metadata_ioctl,
1319 #endif
1320 };
1321
1322 /**
1323  *      lttng_event_ioctl - lttng syscall through ioctl
1324  *
1325  *      @file: the file
1326  *      @cmd: the command
1327  *      @arg: command arg
1328  *
1329  *      This ioctl implements lttng commands:
1330  *      LTTNG_KERNEL_CONTEXT
1331  *              Prepend a context field to each record of this event
1332  *      LTTNG_KERNEL_ENABLE
1333  *              Enable recording for this event (weak enable)
1334  *      LTTNG_KERNEL_DISABLE
1335  *              Disable recording for this event (strong disable)
1336  */
1337 static
1338 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1339 {
1340         struct lttng_event *event;
1341         struct lttng_enabler *enabler;
1342         enum lttng_event_type *evtype = file->private_data;
1343
1344         switch (cmd) {
1345         case LTTNG_KERNEL_OLD_CONTEXT:
1346         {
1347                 /* Not implemented */
1348                 return -ENOSYS;
1349         }
1350         case LTTNG_KERNEL_CONTEXT:
1351         {
1352                 /* Not implemented */
1353                 return -ENOSYS;
1354         }
1355         case LTTNG_KERNEL_OLD_ENABLE:
1356         case LTTNG_KERNEL_ENABLE:
1357                 switch (*evtype) {
1358                 case LTTNG_TYPE_EVENT:
1359                         event = file->private_data;
1360                         return lttng_event_enable(event);
1361                 case LTTNG_TYPE_ENABLER:
1362                         enabler = file->private_data;
1363                         return lttng_enabler_enable(enabler);
1364                 default:
1365                         WARN_ON_ONCE(1);
1366                         return -ENOSYS;
1367                 }
1368         case LTTNG_KERNEL_OLD_DISABLE:
1369         case LTTNG_KERNEL_DISABLE:
1370                 switch (*evtype) {
1371                 case LTTNG_TYPE_EVENT:
1372                         event = file->private_data;
1373                         return lttng_event_disable(event);
1374                 case LTTNG_TYPE_ENABLER:
1375                         enabler = file->private_data;
1376                         return lttng_enabler_disable(enabler);
1377                 default:
1378                         WARN_ON_ONCE(1);
1379                         return -ENOSYS;
1380                 }
1381         case LTTNG_KERNEL_FILTER:
1382                 switch (*evtype) {
1383                 case LTTNG_TYPE_EVENT:
1384                         return -EINVAL;
1385                 case LTTNG_TYPE_ENABLER:
1386                 {
1387                         enabler = file->private_data;
1388                         return lttng_enabler_attach_bytecode(enabler,
1389                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1390                 }
1391
1392                 }
1393         default:
1394                 return -ENOIOCTLCMD;
1395         }
1396 }
1397
1398 static
1399 int lttng_event_release(struct inode *inode, struct file *file)
1400 {
1401         struct lttng_event *event;
1402         struct lttng_enabler *enabler;
1403         enum lttng_event_type *evtype = file->private_data;
1404
1405         if (!evtype)
1406                 return 0;
1407
1408         switch (*evtype) {
1409         case LTTNG_TYPE_EVENT:
1410                 event = file->private_data;
1411                 if (event)
1412                         fput(event->chan->file);
1413                 break;
1414         case LTTNG_TYPE_ENABLER:
1415                 enabler = file->private_data;
1416                 if (enabler)
1417                         fput(enabler->chan->file);
1418                 break;
1419         default:
1420                 WARN_ON_ONCE(1);
1421                 break;
1422         }
1423
1424         return 0;
1425 }
1426
1427 /* TODO: filter control ioctl */
1428 static const struct file_operations lttng_event_fops = {
1429         .owner = THIS_MODULE,
1430         .release = lttng_event_release,
1431         .unlocked_ioctl = lttng_event_ioctl,
1432 #ifdef CONFIG_COMPAT
1433         .compat_ioctl = lttng_event_ioctl,
1434 #endif
1435 };
1436
1437 static int put_u64(uint64_t val, unsigned long arg)
1438 {
1439         return put_user(val, (uint64_t __user *) arg);
1440 }
1441
1442 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1443                 unsigned int cmd, unsigned long arg)
1444 {
1445         struct lib_ring_buffer *buf = filp->private_data;
1446         struct channel *chan = buf->backend.chan;
1447         const struct lib_ring_buffer_config *config = &chan->backend.config;
1448         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1449         int ret;
1450
1451         if (atomic_read(&chan->record_disabled))
1452                 return -EIO;
1453
1454         switch (cmd) {
1455         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1456         {
1457                 uint64_t ts;
1458
1459                 ret = ops->timestamp_begin(config, buf, &ts);
1460                 if (ret < 0)
1461                         goto error;
1462                 return put_u64(ts, arg);
1463         }
1464         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1465         {
1466                 uint64_t ts;
1467
1468                 ret = ops->timestamp_end(config, buf, &ts);
1469                 if (ret < 0)
1470                         goto error;
1471                 return put_u64(ts, arg);
1472         }
1473         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1474         {
1475                 uint64_t ed;
1476
1477                 ret = ops->events_discarded(config, buf, &ed);
1478                 if (ret < 0)
1479                         goto error;
1480                 return put_u64(ed, arg);
1481         }
1482         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1483         {
1484                 uint64_t cs;
1485
1486                 ret = ops->content_size(config, buf, &cs);
1487                 if (ret < 0)
1488                         goto error;
1489                 return put_u64(cs, arg);
1490         }
1491         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1492         {
1493                 uint64_t ps;
1494
1495                 ret = ops->packet_size(config, buf, &ps);
1496                 if (ret < 0)
1497                         goto error;
1498                 return put_u64(ps, arg);
1499         }
1500         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1501         {
1502                 uint64_t si;
1503
1504                 ret = ops->stream_id(config, buf, &si);
1505                 if (ret < 0)
1506                         goto error;
1507                 return put_u64(si, arg);
1508         }
1509         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1510         {
1511                 uint64_t ts;
1512
1513                 ret = ops->current_timestamp(config, buf, &ts);
1514                 if (ret < 0)
1515                         goto error;
1516                 return put_u64(ts, arg);
1517         }
1518         default:
1519                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1520                                 cmd, arg);
1521         }
1522
1523 error:
1524         return -ENOSYS;
1525 }
1526
1527 #ifdef CONFIG_COMPAT
1528 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1529                 unsigned int cmd, unsigned long arg)
1530 {
1531         struct lib_ring_buffer *buf = filp->private_data;
1532         struct channel *chan = buf->backend.chan;
1533         const struct lib_ring_buffer_config *config = &chan->backend.config;
1534         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1535         int ret;
1536
1537         if (atomic_read(&chan->record_disabled))
1538                 return -EIO;
1539
1540         switch (cmd) {
1541         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1542         {
1543                 uint64_t ts;
1544
1545                 ret = ops->timestamp_begin(config, buf, &ts);
1546                 if (ret < 0)
1547                         goto error;
1548                 return put_u64(ts, arg);
1549         }
1550         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1551         {
1552                 uint64_t ts;
1553
1554                 ret = ops->timestamp_end(config, buf, &ts);
1555                 if (ret < 0)
1556                         goto error;
1557                 return put_u64(ts, arg);
1558         }
1559         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1560         {
1561                 uint64_t ed;
1562
1563                 ret = ops->events_discarded(config, buf, &ed);
1564                 if (ret < 0)
1565                         goto error;
1566                 return put_u64(ed, arg);
1567         }
1568         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1569         {
1570                 uint64_t cs;
1571
1572                 ret = ops->content_size(config, buf, &cs);
1573                 if (ret < 0)
1574                         goto error;
1575                 return put_u64(cs, arg);
1576         }
1577         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1578         {
1579                 uint64_t ps;
1580
1581                 ret = ops->packet_size(config, buf, &ps);
1582                 if (ret < 0)
1583                         goto error;
1584                 return put_u64(ps, arg);
1585         }
1586         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1587         {
1588                 uint64_t si;
1589
1590                 ret = ops->stream_id(config, buf, &si);
1591                 if (ret < 0)
1592                         goto error;
1593                 return put_u64(si, arg);
1594         }
1595         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1596         {
1597                 uint64_t ts;
1598
1599                 ret = ops->current_timestamp(config, buf, &ts);
1600                 if (ret < 0)
1601                         goto error;
1602                 return put_u64(ts, arg);
1603         }
1604         default:
1605                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1606                                 cmd, arg);
1607         }
1608
1609 error:
1610         return -ENOSYS;
1611 }
1612 #endif /* CONFIG_COMPAT */
1613
1614 static void lttng_stream_override_ring_buffer_fops(void)
1615 {
1616         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1617         lttng_stream_ring_buffer_file_operations.open =
1618                 lib_ring_buffer_file_operations.open;
1619         lttng_stream_ring_buffer_file_operations.release =
1620                 lib_ring_buffer_file_operations.release;
1621         lttng_stream_ring_buffer_file_operations.poll =
1622                 lib_ring_buffer_file_operations.poll;
1623         lttng_stream_ring_buffer_file_operations.splice_read =
1624                 lib_ring_buffer_file_operations.splice_read;
1625         lttng_stream_ring_buffer_file_operations.mmap =
1626                 lib_ring_buffer_file_operations.mmap;
1627         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1628                 lttng_stream_ring_buffer_ioctl;
1629         lttng_stream_ring_buffer_file_operations.llseek =
1630                 lib_ring_buffer_file_operations.llseek;
1631 #ifdef CONFIG_COMPAT
1632         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1633                 lttng_stream_ring_buffer_compat_ioctl;
1634 #endif
1635 }
1636
1637 int __init lttng_abi_init(void)
1638 {
1639         int ret = 0;
1640
1641         wrapper_vmalloc_sync_all();
1642         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1643                                         &lttng_fops, NULL);
1644
1645         if (!lttng_proc_dentry) {
1646                 printk(KERN_ERR "Error creating LTTng control file\n");
1647                 ret = -ENOMEM;
1648                 goto error;
1649         }
1650         lttng_stream_override_ring_buffer_fops();
1651
1652 error:
1653         return ret;
1654 }
1655
1656 /* No __exit annotation because used by init error path too. */
1657 void lttng_abi_exit(void)
1658 {
1659         if (lttng_proc_dentry)
1660                 remove_proc_entry("lttng", NULL);
1661 }