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