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_EMPTY:   /* Fall-through. */
 688         case RING_BUFFER_FLUSH:
 689         {
 690                 struct lttng_metadata_stream *stream = filp->private_data;
 691                 struct lib_ring_buffer *buf = stream->priv;
 692                 struct channel *chan = buf->backend.chan;
 693
 694                 /*
 695                  * Before doing the actual ring buffer flush, write up to one
 696                  * packet of metadata in the ring buffer.
 697                  */
 698                 ret = lttng_metadata_output_channel(stream, chan);
 699                 if (ret < 0)
 700                         goto err;
 701                 break;
 702         }
 703         case RING_BUFFER_GET_METADATA_VERSION:
 704         {
 705                 struct lttng_metadata_stream *stream = filp->private_data;
 706
 707                 return put_u64(stream->version, arg);
 708         }
 709         default:
 710                 break;
 711         }
 712         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 713
 714         /* Performing lib ring buffer ioctl after our own. */
 715         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 716         if (ret < 0)
 717                 goto err;
 718
 719         switch (cmd) {
 720         case RING_BUFFER_PUT_NEXT_SUBBUF:
 721         {
 722                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 723                                 cmd, arg);
 724                 break;
 725         }
 726         default:
 727                 break;
 728         }
 729 err:
 730         return ret;
 731 }
 732
 733 #ifdef CONFIG_COMPAT
 734 static
 735 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 736                 unsigned int cmd, unsigned long arg)
 737 {
 738         int ret;
 739         struct lttng_metadata_stream *stream = filp->private_data;
 740         struct lib_ring_buffer *buf = stream->priv;
 741
 742         switch (cmd) {
 743         case RING_BUFFER_GET_NEXT_SUBBUF:
 744         {
 745                 struct lttng_metadata_stream *stream = filp->private_data;
 746                 struct lib_ring_buffer *buf = stream->priv;
 747                 struct channel *chan = buf->backend.chan;
 748
 749                 ret = lttng_metadata_output_channel(stream, chan);
 750                 if (ret > 0) {
 751                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 752                         ret = 0;
 753                 } else if (ret < 0)
 754                         goto err;
 755                 break;
 756         }
 757         case RING_BUFFER_GET_SUBBUF:
 758         {
 759                 /*
 760                  * Random access is not allowed for metadata channel.
 761                  */
 762                 return -ENOSYS;
 763         }
 764         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 765         case RING_BUFFER_FLUSH:
 766         {
 767                 struct lttng_metadata_stream *stream = filp->private_data;
 768                 struct lib_ring_buffer *buf = stream->priv;
 769                 struct channel *chan = buf->backend.chan;
 770
 771                 /*
 772                  * Before doing the actual ring buffer flush, write up to one
 773                  * packet of metadata in the ring buffer.
 774                  */
 775                 ret = lttng_metadata_output_channel(stream, chan);
 776                 if (ret < 0)
 777                         goto err;
 778                 break;
 779         }
 780         case RING_BUFFER_GET_METADATA_VERSION:
 781         {
 782                 struct lttng_metadata_stream *stream = filp->private_data;
 783
 784                 return put_u64(stream->version, arg);
 785         }
 786         default:
 787                 break;
 788         }
 789         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 790
 791         /* Performing lib ring buffer ioctl after our own. */
 792         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 793         if (ret < 0)
 794                 goto err;
 795
 796         switch (cmd) {
 797         case RING_BUFFER_PUT_NEXT_SUBBUF:
 798         {
 799                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 800                                 cmd, arg);
 801                 break;
 802         }
 803         default:
 804                 break;
 805         }
 806 err:
 807         return ret;
 808 }
 809 #endif
 810
 811 /*
 812  * This is not used by anonymous file descriptors. This code is left
 813  * there if we ever want to implement an inode with open() operation.
 814  */
 815 static
 816 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 817 {
 818         struct lttng_metadata_stream *stream = inode->i_private;
 819         struct lib_ring_buffer *buf = stream->priv;
 820
 821         file->private_data = buf;
 822         /*
 823          * Since life-time of metadata cache differs from that of
 824          * session, we need to keep our own reference on the transport.
 825          */
 826         if (!try_module_get(stream->transport->owner)) {
 827                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 828                 return -EBUSY;
 829         }
 830         return lib_ring_buffer_open(inode, file, buf);
 831 }
 832
 833 static
 834 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 835 {
 836         struct lttng_metadata_stream *stream = file->private_data;
 837         struct lib_ring_buffer *buf = stream->priv;
 838
 839         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 840         module_put(stream->transport->owner);
 841         return lib_ring_buffer_release(inode, file, buf);
 842 }
 843
 844 static
 845 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 846                 struct pipe_inode_info *pipe, size_t len,
 847                 unsigned int flags)
 848 {
 849         struct lttng_metadata_stream *stream = in->private_data;
 850         struct lib_ring_buffer *buf = stream->priv;
 851
 852         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 853                         flags, buf);
 854 }
 855
 856 static
 857 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 858                 struct vm_area_struct *vma)
 859 {
 860         struct lttng_metadata_stream *stream = filp->private_data;
 861         struct lib_ring_buffer *buf = stream->priv;
 862
 863         return lib_ring_buffer_mmap(filp, vma, buf);
 864 }
 865
 866 static
 867 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 868         .owner = THIS_MODULE,
 869         .open = lttng_metadata_ring_buffer_open,
 870         .release = lttng_metadata_ring_buffer_release,
 871         .poll = lttng_metadata_ring_buffer_poll,
 872         .splice_read = lttng_metadata_ring_buffer_splice_read,
 873         .mmap = lttng_metadata_ring_buffer_mmap,
 874         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 875         .llseek = vfs_lib_ring_buffer_no_llseek,
 876 #ifdef CONFIG_COMPAT
 877         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 878 #endif
 879 };
 880
 881 static
 882 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 883                 const struct file_operations *fops)
 884 {
 885         int stream_fd, ret;
 886         struct file *stream_file;
 887
 888         stream_fd = lttng_get_unused_fd();
 889         if (stream_fd < 0) {
 890                 ret = stream_fd;
 891                 goto fd_error;
 892         }
 893         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 894                         stream_priv, O_RDWR);
 895         if (IS_ERR(stream_file)) {
 896                 ret = PTR_ERR(stream_file);
 897                 goto file_error;
 898         }
 899         /*
 900          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 901          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 902          * file descriptor, so we set FMODE_PREAD here.
 903          */
 904         stream_file->f_mode |= FMODE_PREAD;
 905         fd_install(stream_fd, stream_file);
 906         /*
 907          * The stream holds a reference to the channel within the generic ring
 908          * buffer library, so no need to hold a refcount on the channel and
 909          * session files here.
 910          */
 911         return stream_fd;
 912
 913 file_error:
 914         put_unused_fd(stream_fd);
 915 fd_error:
 916         return ret;
 917 }
 918
 919 static
 920 int lttng_abi_open_stream(struct file *channel_file)
 921 {
 922         struct lttng_channel *channel = channel_file->private_data;
 923         struct lib_ring_buffer *buf;
 924         int ret;
 925         void *stream_priv;
 926
 927         buf = channel->ops->buffer_read_open(channel->chan);
 928         if (!buf)
 929                 return -ENOENT;
 930
 931         stream_priv = buf;
 932         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 933                         &lttng_stream_ring_buffer_file_operations);
 934         if (ret < 0)
 935                 goto fd_error;
 936
 937         return ret;
 938
 939 fd_error:
 940         channel->ops->buffer_read_close(buf);
 941         return ret;
 942 }
 943
 944 static
 945 int lttng_abi_open_metadata_stream(struct file *channel_file)
 946 {
 947         struct lttng_channel *channel = channel_file->private_data;
 948         struct lttng_session *session = channel->session;
 949         struct lib_ring_buffer *buf;
 950         int ret;
 951         struct lttng_metadata_stream *metadata_stream;
 952         void *stream_priv;
 953
 954         buf = channel->ops->buffer_read_open(channel->chan);
 955         if (!buf)
 956                 return -ENOENT;
 957
 958         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 959                         GFP_KERNEL);
 960         if (!metadata_stream) {
 961                 ret = -ENOMEM;
 962                 goto nomem;
 963         }
 964         metadata_stream->metadata_cache = session->metadata_cache;
 965         init_waitqueue_head(&metadata_stream->read_wait);
 966         metadata_stream->priv = buf;
 967         stream_priv = metadata_stream;
 968         metadata_stream->transport = channel->transport;
 969
 970         /*
 971          * Since life-time of metadata cache differs from that of
 972          * session, we need to keep our own reference on the transport.
 973          */
 974         if (!try_module_get(metadata_stream->transport->owner)) {
 975                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 976                 ret = -EINVAL;
 977                 goto notransport;
 978         }
 979
 980         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
 981                 ret = -EOVERFLOW;
 982                 goto kref_error;
 983         }
 984
 985         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 986                         &lttng_metadata_ring_buffer_file_operations);
 987         if (ret < 0)
 988                 goto fd_error;
 989
 990         list_add(&metadata_stream->list,
 991                 &session->metadata_cache->metadata_stream);
 992         return ret;
 993
 994 fd_error:
 995         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 996 kref_error:
 997         module_put(metadata_stream->transport->owner);
 998 notransport:
 999         kfree(metadata_stream);
1000 nomem:
1001         channel->ops->buffer_read_close(buf);
1002         return ret;
1003 }
1004
1005 static
1006 int lttng_abi_create_event(struct file *channel_file,
1007                            struct lttng_kernel_event *event_param)
1008 {
1009         struct lttng_channel *channel = channel_file->private_data;
1010         int event_fd, ret;
1011         struct file *event_file;
1012         void *priv;
1013
1014         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1015         switch (event_param->instrumentation) {
1016         case LTTNG_KERNEL_KRETPROBE:
1017                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1018                 break;
1019         case LTTNG_KERNEL_KPROBE:
1020                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1021                 break;
1022         case LTTNG_KERNEL_FUNCTION:
1023                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1024                 break;
1025         default:
1026                 break;
1027         }
1028         event_fd = lttng_get_unused_fd();
1029         if (event_fd < 0) {
1030                 ret = event_fd;
1031                 goto fd_error;
1032         }
1033         event_file = anon_inode_getfile("[lttng_event]",
1034                                         &lttng_event_fops,
1035                                         NULL, O_RDWR);
1036         if (IS_ERR(event_file)) {
1037                 ret = PTR_ERR(event_file);
1038                 goto file_error;
1039         }
1040         /* The event holds a reference on the channel */
1041         if (atomic_long_add_unless(&channel_file->f_count,
1042                 1, INT_MAX) == INT_MAX) {
1043                 ret = -EOVERFLOW;
1044                 goto refcount_error;
1045         }
1046         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1047                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1048                 struct lttng_enabler *enabler;
1049
1050                 if (strutils_is_star_glob_pattern(event_param->name)) {
1051                         /*
1052                          * If the event name is a star globbing pattern,
1053                          * we create the special star globbing enabler.
1054                          */
1055                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1056                                 event_param, channel);
1057                 } else {
1058                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1059                                 event_param, channel);
1060                 }
1061                 priv = enabler;
1062         } else {
1063                 struct lttng_event *event;
1064
1065                 /*
1066                  * We tolerate no failure path after event creation. It
1067                  * will stay invariant for the rest of the session.
1068                  */
1069                 event = lttng_event_create(channel, event_param,
1070                                 NULL, NULL,
1071                                 event_param->instrumentation);
1072                 WARN_ON_ONCE(!event);
1073                 if (IS_ERR(event)) {
1074                         ret = PTR_ERR(event);
1075                         goto event_error;
1076                 }
1077                 priv = event;
1078         }
1079         event_file->private_data = priv;
1080         fd_install(event_fd, event_file);
1081         return event_fd;
1082
1083 event_error:
1084         atomic_long_dec(&channel_file->f_count);
1085 refcount_error:
1086         fput(event_file);
1087 file_error:
1088         put_unused_fd(event_fd);
1089 fd_error:
1090         return ret;
1091 }
1092
1093 /**
1094  *      lttng_channel_ioctl - lttng syscall through ioctl
1095  *
1096  *      @file: the file
1097  *      @cmd: the command
1098  *      @arg: command arg
1099  *
1100  *      This ioctl implements lttng commands:
1101  *      LTTNG_KERNEL_STREAM
1102  *              Returns an event stream file descriptor or failure.
1103  *              (typically, one event stream records events from one CPU)
1104  *      LTTNG_KERNEL_EVENT
1105  *              Returns an event file descriptor or failure.
1106  *      LTTNG_KERNEL_CONTEXT
1107  *              Prepend a context field to each event in the channel
1108  *      LTTNG_KERNEL_ENABLE
1109  *              Enable recording for events in this channel (weak enable)
1110  *      LTTNG_KERNEL_DISABLE
1111  *              Disable recording for events in this channel (strong disable)
1112  *
1113  * Channel and event file descriptors also hold a reference on the session.
1114  */
1115 static
1116 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1117 {
1118         struct lttng_channel *channel = file->private_data;
1119
1120         switch (cmd) {
1121         case LTTNG_KERNEL_OLD_STREAM:
1122         case LTTNG_KERNEL_STREAM:
1123                 return lttng_abi_open_stream(file);
1124         case LTTNG_KERNEL_OLD_EVENT:
1125         {
1126                 struct lttng_kernel_event *uevent_param;
1127                 struct lttng_kernel_old_event *old_uevent_param;
1128                 int ret;
1129
1130                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1131                                 GFP_KERNEL);
1132                 if (!uevent_param) {
1133                         ret = -ENOMEM;
1134                         goto old_event_end;
1135                 }
1136                 old_uevent_param = kmalloc(
1137                                 sizeof(struct lttng_kernel_old_event),
1138                                 GFP_KERNEL);
1139                 if (!old_uevent_param) {
1140                         ret = -ENOMEM;
1141                         goto old_event_error_free_param;
1142                 }
1143                 if (copy_from_user(old_uevent_param,
1144                                 (struct lttng_kernel_old_event __user *) arg,
1145                                 sizeof(struct lttng_kernel_old_event))) {
1146                         ret = -EFAULT;
1147                         goto old_event_error_free_old_param;
1148                 }
1149
1150                 memcpy(uevent_param->name, old_uevent_param->name,
1151                                 sizeof(uevent_param->name));
1152                 uevent_param->instrumentation =
1153                         old_uevent_param->instrumentation;
1154
1155                 switch (old_uevent_param->instrumentation) {
1156                 case LTTNG_KERNEL_KPROBE:
1157                         uevent_param->u.kprobe.addr =
1158                                 old_uevent_param->u.kprobe.addr;
1159                         uevent_param->u.kprobe.offset =
1160                                 old_uevent_param->u.kprobe.offset;
1161                         memcpy(uevent_param->u.kprobe.symbol_name,
1162                                 old_uevent_param->u.kprobe.symbol_name,
1163                                 sizeof(uevent_param->u.kprobe.symbol_name));
1164                         break;
1165                 case LTTNG_KERNEL_KRETPROBE:
1166                         uevent_param->u.kretprobe.addr =
1167                                 old_uevent_param->u.kretprobe.addr;
1168                         uevent_param->u.kretprobe.offset =
1169                                 old_uevent_param->u.kretprobe.offset;
1170                         memcpy(uevent_param->u.kretprobe.symbol_name,
1171                                 old_uevent_param->u.kretprobe.symbol_name,
1172                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1173                         break;
1174                 case LTTNG_KERNEL_FUNCTION:
1175                         memcpy(uevent_param->u.ftrace.symbol_name,
1176                                         old_uevent_param->u.ftrace.symbol_name,
1177                                         sizeof(uevent_param->u.ftrace.symbol_name));
1178                         break;
1179                 default:
1180                         break;
1181                 }
1182                 ret = lttng_abi_create_event(file, uevent_param);
1183
1184 old_event_error_free_old_param:
1185                 kfree(old_uevent_param);
1186 old_event_error_free_param:
1187                 kfree(uevent_param);
1188 old_event_end:
1189                 return ret;
1190         }
1191         case LTTNG_KERNEL_EVENT:
1192         {
1193                 struct lttng_kernel_event uevent_param;
1194
1195                 if (copy_from_user(&uevent_param,
1196                                 (struct lttng_kernel_event __user *) arg,
1197                                 sizeof(uevent_param)))
1198                         return -EFAULT;
1199                 return lttng_abi_create_event(file, &uevent_param);
1200         }
1201         case LTTNG_KERNEL_OLD_CONTEXT:
1202         {
1203                 struct lttng_kernel_context *ucontext_param;
1204                 struct lttng_kernel_old_context *old_ucontext_param;
1205                 int ret;
1206
1207                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1208                                 GFP_KERNEL);
1209                 if (!ucontext_param) {
1210                         ret = -ENOMEM;
1211                         goto old_ctx_end;
1212                 }
1213                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1214                                 GFP_KERNEL);
1215                 if (!old_ucontext_param) {
1216                         ret = -ENOMEM;
1217                         goto old_ctx_error_free_param;
1218                 }
1219
1220                 if (copy_from_user(old_ucontext_param,
1221                                 (struct lttng_kernel_old_context __user *) arg,
1222                                 sizeof(struct lttng_kernel_old_context))) {
1223                         ret = -EFAULT;
1224                         goto old_ctx_error_free_old_param;
1225                 }
1226                 ucontext_param->ctx = old_ucontext_param->ctx;
1227                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1228                                 sizeof(ucontext_param->padding));
1229                 /* only type that uses the union */
1230                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1231                         ucontext_param->u.perf_counter.type =
1232                                 old_ucontext_param->u.perf_counter.type;
1233                         ucontext_param->u.perf_counter.config =
1234                                 old_ucontext_param->u.perf_counter.config;
1235                         memcpy(ucontext_param->u.perf_counter.name,
1236                                 old_ucontext_param->u.perf_counter.name,
1237                                 sizeof(ucontext_param->u.perf_counter.name));
1238                 }
1239
1240                 ret = lttng_abi_add_context(file,
1241                                 ucontext_param,
1242                                 &channel->ctx, channel->session);
1243
1244 old_ctx_error_free_old_param:
1245                 kfree(old_ucontext_param);
1246 old_ctx_error_free_param:
1247                 kfree(ucontext_param);
1248 old_ctx_end:
1249                 return ret;
1250         }
1251         case LTTNG_KERNEL_CONTEXT:
1252         {
1253                 struct lttng_kernel_context ucontext_param;
1254
1255                 if (copy_from_user(&ucontext_param,
1256                                 (struct lttng_kernel_context __user *) arg,
1257                                 sizeof(ucontext_param)))
1258                         return -EFAULT;
1259                 return lttng_abi_add_context(file,
1260                                 &ucontext_param,
1261                                 &channel->ctx, channel->session);
1262         }
1263         case LTTNG_KERNEL_OLD_ENABLE:
1264         case LTTNG_KERNEL_ENABLE:
1265                 return lttng_channel_enable(channel);
1266         case LTTNG_KERNEL_OLD_DISABLE:
1267         case LTTNG_KERNEL_DISABLE:
1268                 return lttng_channel_disable(channel);
1269         case LTTNG_KERNEL_SYSCALL_MASK:
1270                 return lttng_channel_syscall_mask(channel,
1271                         (struct lttng_kernel_syscall_mask __user *) arg);
1272         default:
1273                 return -ENOIOCTLCMD;
1274         }
1275
1276 }
1277
1278 /**
1279  *      lttng_metadata_ioctl - lttng syscall through ioctl
1280  *
1281  *      @file: the file
1282  *      @cmd: the command
1283  *      @arg: command arg
1284  *
1285  *      This ioctl implements lttng commands:
1286  *      LTTNG_KERNEL_STREAM
1287  *              Returns an event stream file descriptor or failure.
1288  *
1289  * Channel and event file descriptors also hold a reference on the session.
1290  */
1291 static
1292 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1293 {
1294         switch (cmd) {
1295         case LTTNG_KERNEL_OLD_STREAM:
1296         case LTTNG_KERNEL_STREAM:
1297                 return lttng_abi_open_metadata_stream(file);
1298         default:
1299                 return -ENOIOCTLCMD;
1300         }
1301 }
1302
1303 /**
1304  *      lttng_channel_poll - lttng stream addition/removal monitoring
1305  *
1306  *      @file: the file
1307  *      @wait: poll table
1308  */
1309 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1310 {
1311         struct lttng_channel *channel = file->private_data;
1312         unsigned int mask = 0;
1313
1314         if (file->f_mode & FMODE_READ) {
1315                 poll_wait_set_exclusive(wait);
1316                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1317                           wait);
1318
1319                 if (channel->ops->is_disabled(channel->chan))
1320                         return POLLERR;
1321                 if (channel->ops->is_finalized(channel->chan))
1322                         return POLLHUP;
1323                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1324                         return POLLIN | POLLRDNORM;
1325                 return 0;
1326         }
1327         return mask;
1328
1329 }
1330
1331 static
1332 int lttng_channel_release(struct inode *inode, struct file *file)
1333 {
1334         struct lttng_channel *channel = file->private_data;
1335
1336         if (channel)
1337                 fput(channel->session->file);
1338         return 0;
1339 }
1340
1341 static
1342 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1343 {
1344         struct lttng_channel *channel = file->private_data;
1345
1346         if (channel) {
1347                 fput(channel->session->file);
1348                 lttng_metadata_channel_destroy(channel);
1349         }
1350
1351         return 0;
1352 }
1353
1354 static const struct file_operations lttng_channel_fops = {
1355         .owner = THIS_MODULE,
1356         .release = lttng_channel_release,
1357         .poll = lttng_channel_poll,
1358         .unlocked_ioctl = lttng_channel_ioctl,
1359 #ifdef CONFIG_COMPAT
1360         .compat_ioctl = lttng_channel_ioctl,
1361 #endif
1362 };
1363
1364 static const struct file_operations lttng_metadata_fops = {
1365         .owner = THIS_MODULE,
1366         .release = lttng_metadata_channel_release,
1367         .unlocked_ioctl = lttng_metadata_ioctl,
1368 #ifdef CONFIG_COMPAT
1369         .compat_ioctl = lttng_metadata_ioctl,
1370 #endif
1371 };
1372
1373 /**
1374  *      lttng_event_ioctl - lttng syscall through ioctl
1375  *
1376  *      @file: the file
1377  *      @cmd: the command
1378  *      @arg: command arg
1379  *
1380  *      This ioctl implements lttng commands:
1381  *      LTTNG_KERNEL_CONTEXT
1382  *              Prepend a context field to each record of this event
1383  *      LTTNG_KERNEL_ENABLE
1384  *              Enable recording for this event (weak enable)
1385  *      LTTNG_KERNEL_DISABLE
1386  *              Disable recording for this event (strong disable)
1387  */
1388 static
1389 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1390 {
1391         struct lttng_event *event;
1392         struct lttng_enabler *enabler;
1393         enum lttng_event_type *evtype = file->private_data;
1394
1395         switch (cmd) {
1396         case LTTNG_KERNEL_OLD_CONTEXT:
1397         {
1398                 /* Not implemented */
1399                 return -ENOSYS;
1400         }
1401         case LTTNG_KERNEL_CONTEXT:
1402         {
1403                 /* Not implemented */
1404                 return -ENOSYS;
1405         }
1406         case LTTNG_KERNEL_OLD_ENABLE:
1407         case LTTNG_KERNEL_ENABLE:
1408                 switch (*evtype) {
1409                 case LTTNG_TYPE_EVENT:
1410                         event = file->private_data;
1411                         return lttng_event_enable(event);
1412                 case LTTNG_TYPE_ENABLER:
1413                         enabler = file->private_data;
1414                         return lttng_enabler_enable(enabler);
1415                 default:
1416                         WARN_ON_ONCE(1);
1417                         return -ENOSYS;
1418                 }
1419         case LTTNG_KERNEL_OLD_DISABLE:
1420         case LTTNG_KERNEL_DISABLE:
1421                 switch (*evtype) {
1422                 case LTTNG_TYPE_EVENT:
1423                         event = file->private_data;
1424                         return lttng_event_disable(event);
1425                 case LTTNG_TYPE_ENABLER:
1426                         enabler = file->private_data;
1427                         return lttng_enabler_disable(enabler);
1428                 default:
1429                         WARN_ON_ONCE(1);
1430                         return -ENOSYS;
1431                 }
1432         case LTTNG_KERNEL_FILTER:
1433                 switch (*evtype) {
1434                 case LTTNG_TYPE_EVENT:
1435                         return -EINVAL;
1436                 case LTTNG_TYPE_ENABLER:
1437                 {
1438                         enabler = file->private_data;
1439                         return lttng_enabler_attach_bytecode(enabler,
1440                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1441                 }
1442
1443                 }
1444         default:
1445                 return -ENOIOCTLCMD;
1446         }
1447 }
1448
1449 static
1450 int lttng_event_release(struct inode *inode, struct file *file)
1451 {
1452         struct lttng_event *event;
1453         struct lttng_enabler *enabler;
1454         enum lttng_event_type *evtype = file->private_data;
1455
1456         if (!evtype)
1457                 return 0;
1458
1459         switch (*evtype) {
1460         case LTTNG_TYPE_EVENT:
1461                 event = file->private_data;
1462                 if (event)
1463                         fput(event->chan->file);
1464                 break;
1465         case LTTNG_TYPE_ENABLER:
1466                 enabler = file->private_data;
1467                 if (enabler)
1468                         fput(enabler->chan->file);
1469                 break;
1470         default:
1471                 WARN_ON_ONCE(1);
1472                 break;
1473         }
1474
1475         return 0;
1476 }
1477
1478 /* TODO: filter control ioctl */
1479 static const struct file_operations lttng_event_fops = {
1480         .owner = THIS_MODULE,
1481         .release = lttng_event_release,
1482         .unlocked_ioctl = lttng_event_ioctl,
1483 #ifdef CONFIG_COMPAT
1484         .compat_ioctl = lttng_event_ioctl,
1485 #endif
1486 };
1487
1488 static int put_u64(uint64_t val, unsigned long arg)
1489 {
1490         return put_user(val, (uint64_t __user *) arg);
1491 }
1492
1493 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1494                 unsigned int cmd, unsigned long arg)
1495 {
1496         struct lib_ring_buffer *buf = filp->private_data;
1497         struct channel *chan = buf->backend.chan;
1498         const struct lib_ring_buffer_config *config = &chan->backend.config;
1499         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1500         int ret;
1501
1502         if (atomic_read(&chan->record_disabled))
1503                 return -EIO;
1504
1505         switch (cmd) {
1506         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1507         {
1508                 uint64_t ts;
1509
1510                 ret = ops->timestamp_begin(config, buf, &ts);
1511                 if (ret < 0)
1512                         goto error;
1513                 return put_u64(ts, arg);
1514         }
1515         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1516         {
1517                 uint64_t ts;
1518
1519                 ret = ops->timestamp_end(config, buf, &ts);
1520                 if (ret < 0)
1521                         goto error;
1522                 return put_u64(ts, arg);
1523         }
1524         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1525         {
1526                 uint64_t ed;
1527
1528                 ret = ops->events_discarded(config, buf, &ed);
1529                 if (ret < 0)
1530                         goto error;
1531                 return put_u64(ed, arg);
1532         }
1533         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1534         {
1535                 uint64_t cs;
1536
1537                 ret = ops->content_size(config, buf, &cs);
1538                 if (ret < 0)
1539                         goto error;
1540                 return put_u64(cs, arg);
1541         }
1542         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1543         {
1544                 uint64_t ps;
1545
1546                 ret = ops->packet_size(config, buf, &ps);
1547                 if (ret < 0)
1548                         goto error;
1549                 return put_u64(ps, arg);
1550         }
1551         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1552         {
1553                 uint64_t si;
1554
1555                 ret = ops->stream_id(config, buf, &si);
1556                 if (ret < 0)
1557                         goto error;
1558                 return put_u64(si, arg);
1559         }
1560         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1561         {
1562                 uint64_t ts;
1563
1564                 ret = ops->current_timestamp(config, buf, &ts);
1565                 if (ret < 0)
1566                         goto error;
1567                 return put_u64(ts, arg);
1568         }
1569         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1570         {
1571                 uint64_t seq;
1572
1573                 ret = ops->sequence_number(config, buf, &seq);
1574                 if (ret < 0)
1575                         goto error;
1576                 return put_u64(seq, arg);
1577         }
1578         case LTTNG_RING_BUFFER_INSTANCE_ID:
1579         {
1580                 uint64_t id;
1581
1582                 ret = ops->instance_id(config, buf, &id);
1583                 if (ret < 0)
1584                         goto error;
1585                 return put_u64(id, arg);
1586         }
1587         default:
1588                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1589                                 cmd, arg);
1590         }
1591
1592 error:
1593         return -ENOSYS;
1594 }
1595
1596 #ifdef CONFIG_COMPAT
1597 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1598                 unsigned int cmd, unsigned long arg)
1599 {
1600         struct lib_ring_buffer *buf = filp->private_data;
1601         struct channel *chan = buf->backend.chan;
1602         const struct lib_ring_buffer_config *config = &chan->backend.config;
1603         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1604         int ret;
1605
1606         if (atomic_read(&chan->record_disabled))
1607                 return -EIO;
1608
1609         switch (cmd) {
1610         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1611         {
1612                 uint64_t ts;
1613
1614                 ret = ops->timestamp_begin(config, buf, &ts);
1615                 if (ret < 0)
1616                         goto error;
1617                 return put_u64(ts, arg);
1618         }
1619         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1620         {
1621                 uint64_t ts;
1622
1623                 ret = ops->timestamp_end(config, buf, &ts);
1624                 if (ret < 0)
1625                         goto error;
1626                 return put_u64(ts, arg);
1627         }
1628         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1629         {
1630                 uint64_t ed;
1631
1632                 ret = ops->events_discarded(config, buf, &ed);
1633                 if (ret < 0)
1634                         goto error;
1635                 return put_u64(ed, arg);
1636         }
1637         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1638         {
1639                 uint64_t cs;
1640
1641                 ret = ops->content_size(config, buf, &cs);
1642                 if (ret < 0)
1643                         goto error;
1644                 return put_u64(cs, arg);
1645         }
1646         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1647         {
1648                 uint64_t ps;
1649
1650                 ret = ops->packet_size(config, buf, &ps);
1651                 if (ret < 0)
1652                         goto error;
1653                 return put_u64(ps, arg);
1654         }
1655         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1656         {
1657                 uint64_t si;
1658
1659                 ret = ops->stream_id(config, buf, &si);
1660                 if (ret < 0)
1661                         goto error;
1662                 return put_u64(si, arg);
1663         }
1664         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1665         {
1666                 uint64_t ts;
1667
1668                 ret = ops->current_timestamp(config, buf, &ts);
1669                 if (ret < 0)
1670                         goto error;
1671                 return put_u64(ts, arg);
1672         }
1673         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1674         {
1675                 uint64_t seq;
1676
1677                 ret = ops->sequence_number(config, buf, &seq);
1678                 if (ret < 0)
1679                         goto error;
1680                 return put_u64(seq, arg);
1681         }
1682         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1683         {
1684                 uint64_t id;
1685
1686                 ret = ops->instance_id(config, buf, &id);
1687                 if (ret < 0)
1688                         goto error;
1689                 return put_u64(id, arg);
1690         }
1691         default:
1692                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1693                                 cmd, arg);
1694         }
1695
1696 error:
1697         return -ENOSYS;
1698 }
1699 #endif /* CONFIG_COMPAT */
1700
1701 static void lttng_stream_override_ring_buffer_fops(void)
1702 {
1703         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1704         lttng_stream_ring_buffer_file_operations.open =
1705                 lib_ring_buffer_file_operations.open;
1706         lttng_stream_ring_buffer_file_operations.release =
1707                 lib_ring_buffer_file_operations.release;
1708         lttng_stream_ring_buffer_file_operations.poll =
1709                 lib_ring_buffer_file_operations.poll;
1710         lttng_stream_ring_buffer_file_operations.splice_read =
1711                 lib_ring_buffer_file_operations.splice_read;
1712         lttng_stream_ring_buffer_file_operations.mmap =
1713                 lib_ring_buffer_file_operations.mmap;
1714         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1715                 lttng_stream_ring_buffer_ioctl;
1716         lttng_stream_ring_buffer_file_operations.llseek =
1717                 lib_ring_buffer_file_operations.llseek;
1718 #ifdef CONFIG_COMPAT
1719         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1720                 lttng_stream_ring_buffer_compat_ioctl;
1721 #endif
1722 }
1723
1724 int __init lttng_abi_init(void)
1725 {
1726         int ret = 0;
1727
1728         wrapper_vmalloc_sync_all();
1729         lttng_clock_ref();
1730         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1731                                         &lttng_fops, NULL);
1732
1733         if (!lttng_proc_dentry) {
1734                 printk(KERN_ERR "Error creating LTTng control file\n");
1735                 ret = -ENOMEM;
1736                 goto error;
1737         }
1738         lttng_stream_override_ring_buffer_fops();
1739         return 0;
1740
1741 error:
1742         lttng_clock_unref();
1743         return ret;
1744 }
1745
1746 /* No __exit annotation because used by init error path too. */
1747 void lttng_abi_exit(void)
1748 {
1749         lttng_clock_unref();
1750         if (lttng_proc_dentry)
1751                 remove_proc_entry("lttng", NULL);
1752 }