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 /*
 658  * Reset the counter of how much metadata has been consumed to 0. That way,
 659  * the consumer receives the content of the metadata cache unchanged. This is
 660  * different from the metadata_regenerate where the offset from epoch is
 661  * resampled, here we want the exact same content as the last time the metadata
 662  * was generated. This command is only possible if all the metadata written
 663  * in the cache has been output to the metadata stream to avoid corrupting the
 664  * metadata file.
 665  *
 666  * Return 0 on success, a negative value on error.
 667  */
 668 static
 669 int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
 670 {
 671         int ret;
 672         struct lttng_metadata_cache *cache = stream->metadata_cache;
 673
 674         mutex_lock(&cache->lock);
 675         if (stream->metadata_out != cache->metadata_written) {
 676                 ret = -EBUSY;
 677                 goto end;
 678         }
 679         stream->metadata_out = 0;
 680         stream->metadata_in = 0;
 681         wake_up_interruptible(&stream->read_wait);
 682         ret = 0;
 683
 684 end:
 685         mutex_unlock(&cache->lock);
 686         return ret;
 687 }
 688
 689 static
 690 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 691                 unsigned int cmd, unsigned long arg)
 692 {
 693         int ret;
 694         struct lttng_metadata_stream *stream = filp->private_data;
 695         struct lib_ring_buffer *buf = stream->priv;
 696
 697         switch (cmd) {
 698         case RING_BUFFER_GET_NEXT_SUBBUF:
 699         {
 700                 struct lttng_metadata_stream *stream = filp->private_data;
 701                 struct lib_ring_buffer *buf = stream->priv;
 702                 struct channel *chan = buf->backend.chan;
 703
 704                 ret = lttng_metadata_output_channel(stream, chan);
 705                 if (ret > 0) {
 706                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 707                         ret = 0;
 708                 } else if (ret < 0)
 709                         goto err;
 710                 break;
 711         }
 712         case RING_BUFFER_GET_SUBBUF:
 713         {
 714                 /*
 715                  * Random access is not allowed for metadata channel.
 716                  */
 717                 return -ENOSYS;
 718         }
 719         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 720         case RING_BUFFER_FLUSH:
 721         {
 722                 struct lttng_metadata_stream *stream = filp->private_data;
 723                 struct lib_ring_buffer *buf = stream->priv;
 724                 struct channel *chan = buf->backend.chan;
 725
 726                 /*
 727                  * Before doing the actual ring buffer flush, write up to one
 728                  * packet of metadata in the ring buffer.
 729                  */
 730                 ret = lttng_metadata_output_channel(stream, chan);
 731                 if (ret < 0)
 732                         goto err;
 733                 break;
 734         }
 735         case RING_BUFFER_GET_METADATA_VERSION:
 736         {
 737                 struct lttng_metadata_stream *stream = filp->private_data;
 738
 739                 return put_u64(stream->version, arg);
 740         }
 741         case RING_BUFFER_METADATA_CACHE_DUMP:
 742         {
 743                 struct lttng_metadata_stream *stream = filp->private_data;
 744
 745                 return lttng_metadata_cache_dump(stream);
 746         }
 747         default:
 748                 break;
 749         }
 750         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 751
 752         /* Performing lib ring buffer ioctl after our own. */
 753         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 754         if (ret < 0)
 755                 goto err;
 756
 757         switch (cmd) {
 758         case RING_BUFFER_PUT_NEXT_SUBBUF:
 759         {
 760                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 761                                 cmd, arg);
 762                 break;
 763         }
 764         default:
 765                 break;
 766         }
 767 err:
 768         return ret;
 769 }
 770
 771 #ifdef CONFIG_COMPAT
 772 static
 773 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 774                 unsigned int cmd, unsigned long arg)
 775 {
 776         int ret;
 777         struct lttng_metadata_stream *stream = filp->private_data;
 778         struct lib_ring_buffer *buf = stream->priv;
 779
 780         switch (cmd) {
 781         case RING_BUFFER_GET_NEXT_SUBBUF:
 782         {
 783                 struct lttng_metadata_stream *stream = filp->private_data;
 784                 struct lib_ring_buffer *buf = stream->priv;
 785                 struct channel *chan = buf->backend.chan;
 786
 787                 ret = lttng_metadata_output_channel(stream, chan);
 788                 if (ret > 0) {
 789                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 790                         ret = 0;
 791                 } else if (ret < 0)
 792                         goto err;
 793                 break;
 794         }
 795         case RING_BUFFER_GET_SUBBUF:
 796         {
 797                 /*
 798                  * Random access is not allowed for metadata channel.
 799                  */
 800                 return -ENOSYS;
 801         }
 802         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 803         case RING_BUFFER_FLUSH:
 804         {
 805                 struct lttng_metadata_stream *stream = filp->private_data;
 806                 struct lib_ring_buffer *buf = stream->priv;
 807                 struct channel *chan = buf->backend.chan;
 808
 809                 /*
 810                  * Before doing the actual ring buffer flush, write up to one
 811                  * packet of metadata in the ring buffer.
 812                  */
 813                 ret = lttng_metadata_output_channel(stream, chan);
 814                 if (ret < 0)
 815                         goto err;
 816                 break;
 817         }
 818         case RING_BUFFER_GET_METADATA_VERSION:
 819         {
 820                 struct lttng_metadata_stream *stream = filp->private_data;
 821
 822                 return put_u64(stream->version, arg);
 823         }
 824         case RING_BUFFER_METADATA_CACHE_DUMP:
 825         {
 826                 struct lttng_metadata_stream *stream = filp->private_data;
 827
 828                 return lttng_metadata_cache_dump(stream);
 829         }
 830         default:
 831                 break;
 832         }
 833         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 834
 835         /* Performing lib ring buffer ioctl after our own. */
 836         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 837         if (ret < 0)
 838                 goto err;
 839
 840         switch (cmd) {
 841         case RING_BUFFER_PUT_NEXT_SUBBUF:
 842         {
 843                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 844                                 cmd, arg);
 845                 break;
 846         }
 847         default:
 848                 break;
 849         }
 850 err:
 851         return ret;
 852 }
 853 #endif
 854
 855 /*
 856  * This is not used by anonymous file descriptors. This code is left
 857  * there if we ever want to implement an inode with open() operation.
 858  */
 859 static
 860 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 861 {
 862         struct lttng_metadata_stream *stream = inode->i_private;
 863         struct lib_ring_buffer *buf = stream->priv;
 864
 865         file->private_data = buf;
 866         /*
 867          * Since life-time of metadata cache differs from that of
 868          * session, we need to keep our own reference on the transport.
 869          */
 870         if (!try_module_get(stream->transport->owner)) {
 871                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 872                 return -EBUSY;
 873         }
 874         return lib_ring_buffer_open(inode, file, buf);
 875 }
 876
 877 static
 878 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 879 {
 880         struct lttng_metadata_stream *stream = file->private_data;
 881         struct lib_ring_buffer *buf = stream->priv;
 882
 883         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 884         module_put(stream->transport->owner);
 885         return lib_ring_buffer_release(inode, file, buf);
 886 }
 887
 888 static
 889 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 890                 struct pipe_inode_info *pipe, size_t len,
 891                 unsigned int flags)
 892 {
 893         struct lttng_metadata_stream *stream = in->private_data;
 894         struct lib_ring_buffer *buf = stream->priv;
 895
 896         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 897                         flags, buf);
 898 }
 899
 900 static
 901 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 902                 struct vm_area_struct *vma)
 903 {
 904         struct lttng_metadata_stream *stream = filp->private_data;
 905         struct lib_ring_buffer *buf = stream->priv;
 906
 907         return lib_ring_buffer_mmap(filp, vma, buf);
 908 }
 909
 910 static
 911 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 912         .owner = THIS_MODULE,
 913         .open = lttng_metadata_ring_buffer_open,
 914         .release = lttng_metadata_ring_buffer_release,
 915         .poll = lttng_metadata_ring_buffer_poll,
 916         .splice_read = lttng_metadata_ring_buffer_splice_read,
 917         .mmap = lttng_metadata_ring_buffer_mmap,
 918         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 919         .llseek = vfs_lib_ring_buffer_no_llseek,
 920 #ifdef CONFIG_COMPAT
 921         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 922 #endif
 923 };
 924
 925 static
 926 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 927                 const struct file_operations *fops)
 928 {
 929         int stream_fd, ret;
 930         struct file *stream_file;
 931
 932         stream_fd = lttng_get_unused_fd();
 933         if (stream_fd < 0) {
 934                 ret = stream_fd;
 935                 goto fd_error;
 936         }
 937         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 938                         stream_priv, O_RDWR);
 939         if (IS_ERR(stream_file)) {
 940                 ret = PTR_ERR(stream_file);
 941                 goto file_error;
 942         }
 943         /*
 944          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 945          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 946          * file descriptor, so we set FMODE_PREAD here.
 947          */
 948         stream_file->f_mode |= FMODE_PREAD;
 949         fd_install(stream_fd, stream_file);
 950         /*
 951          * The stream holds a reference to the channel within the generic ring
 952          * buffer library, so no need to hold a refcount on the channel and
 953          * session files here.
 954          */
 955         return stream_fd;
 956
 957 file_error:
 958         put_unused_fd(stream_fd);
 959 fd_error:
 960         return ret;
 961 }
 962
 963 static
 964 int lttng_abi_open_stream(struct file *channel_file)
 965 {
 966         struct lttng_channel *channel = channel_file->private_data;
 967         struct lib_ring_buffer *buf;
 968         int ret;
 969         void *stream_priv;
 970
 971         buf = channel->ops->buffer_read_open(channel->chan);
 972         if (!buf)
 973                 return -ENOENT;
 974
 975         stream_priv = buf;
 976         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 977                         &lttng_stream_ring_buffer_file_operations);
 978         if (ret < 0)
 979                 goto fd_error;
 980
 981         return ret;
 982
 983 fd_error:
 984         channel->ops->buffer_read_close(buf);
 985         return ret;
 986 }
 987
 988 static
 989 int lttng_abi_open_metadata_stream(struct file *channel_file)
 990 {
 991         struct lttng_channel *channel = channel_file->private_data;
 992         struct lttng_session *session = channel->session;
 993         struct lib_ring_buffer *buf;
 994         int ret;
 995         struct lttng_metadata_stream *metadata_stream;
 996         void *stream_priv;
 997
 998         buf = channel->ops->buffer_read_open(channel->chan);
 999         if (!buf)
1000                 return -ENOENT;
1001
1002         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
1003                         GFP_KERNEL);
1004         if (!metadata_stream) {
1005                 ret = -ENOMEM;
1006                 goto nomem;
1007         }
1008         metadata_stream->metadata_cache = session->metadata_cache;
1009         init_waitqueue_head(&metadata_stream->read_wait);
1010         metadata_stream->priv = buf;
1011         stream_priv = metadata_stream;
1012         metadata_stream->transport = channel->transport;
1013
1014         /*
1015          * Since life-time of metadata cache differs from that of
1016          * session, we need to keep our own reference on the transport.
1017          */
1018         if (!try_module_get(metadata_stream->transport->owner)) {
1019                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
1020                 ret = -EINVAL;
1021                 goto notransport;
1022         }
1023
1024         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1025                 ret = -EOVERFLOW;
1026                 goto kref_error;
1027         }
1028
1029         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1030                         &lttng_metadata_ring_buffer_file_operations);
1031         if (ret < 0)
1032                 goto fd_error;
1033
1034         list_add(&metadata_stream->list,
1035                 &session->metadata_cache->metadata_stream);
1036         return ret;
1037
1038 fd_error:
1039         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1040 kref_error:
1041         module_put(metadata_stream->transport->owner);
1042 notransport:
1043         kfree(metadata_stream);
1044 nomem:
1045         channel->ops->buffer_read_close(buf);
1046         return ret;
1047 }
1048
1049 static
1050 int lttng_abi_create_event(struct file *channel_file,
1051                            struct lttng_kernel_event *event_param)
1052 {
1053         struct lttng_channel *channel = channel_file->private_data;
1054         int event_fd, ret;
1055         struct file *event_file;
1056         void *priv;
1057
1058         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1059         switch (event_param->instrumentation) {
1060         case LTTNG_KERNEL_KRETPROBE:
1061                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1062                 break;
1063         case LTTNG_KERNEL_KPROBE:
1064                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1065                 break;
1066         case LTTNG_KERNEL_FUNCTION:
1067                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1068                 break;
1069         default:
1070                 break;
1071         }
1072         event_fd = lttng_get_unused_fd();
1073         if (event_fd < 0) {
1074                 ret = event_fd;
1075                 goto fd_error;
1076         }
1077         event_file = anon_inode_getfile("[lttng_event]",
1078                                         &lttng_event_fops,
1079                                         NULL, O_RDWR);
1080         if (IS_ERR(event_file)) {
1081                 ret = PTR_ERR(event_file);
1082                 goto file_error;
1083         }
1084         /* The event holds a reference on the channel */
1085         if (atomic_long_add_unless(&channel_file->f_count,
1086                 1, INT_MAX) == INT_MAX) {
1087                 ret = -EOVERFLOW;
1088                 goto refcount_error;
1089         }
1090         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1091                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1092                 struct lttng_enabler *enabler;
1093
1094                 if (strutils_is_star_glob_pattern(event_param->name)) {
1095                         /*
1096                          * If the event name is a star globbing pattern,
1097                          * we create the special star globbing enabler.
1098                          */
1099                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1100                                 event_param, channel);
1101                 } else {
1102                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1103                                 event_param, channel);
1104                 }
1105                 priv = enabler;
1106         } else {
1107                 struct lttng_event *event;
1108
1109                 /*
1110                  * We tolerate no failure path after event creation. It
1111                  * will stay invariant for the rest of the session.
1112                  */
1113                 event = lttng_event_create(channel, event_param,
1114                                 NULL, NULL,
1115                                 event_param->instrumentation);
1116                 WARN_ON_ONCE(!event);
1117                 if (IS_ERR(event)) {
1118                         ret = PTR_ERR(event);
1119                         goto event_error;
1120                 }
1121                 priv = event;
1122         }
1123         event_file->private_data = priv;
1124         fd_install(event_fd, event_file);
1125         return event_fd;
1126
1127 event_error:
1128         atomic_long_dec(&channel_file->f_count);
1129 refcount_error:
1130         fput(event_file);
1131 file_error:
1132         put_unused_fd(event_fd);
1133 fd_error:
1134         return ret;
1135 }
1136
1137 /**
1138  *      lttng_channel_ioctl - lttng syscall through ioctl
1139  *
1140  *      @file: the file
1141  *      @cmd: the command
1142  *      @arg: command arg
1143  *
1144  *      This ioctl implements lttng commands:
1145  *      LTTNG_KERNEL_STREAM
1146  *              Returns an event stream file descriptor or failure.
1147  *              (typically, one event stream records events from one CPU)
1148  *      LTTNG_KERNEL_EVENT
1149  *              Returns an event file descriptor or failure.
1150  *      LTTNG_KERNEL_CONTEXT
1151  *              Prepend a context field to each event in the channel
1152  *      LTTNG_KERNEL_ENABLE
1153  *              Enable recording for events in this channel (weak enable)
1154  *      LTTNG_KERNEL_DISABLE
1155  *              Disable recording for events in this channel (strong disable)
1156  *
1157  * Channel and event file descriptors also hold a reference on the session.
1158  */
1159 static
1160 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1161 {
1162         struct lttng_channel *channel = file->private_data;
1163
1164         switch (cmd) {
1165         case LTTNG_KERNEL_OLD_STREAM:
1166         case LTTNG_KERNEL_STREAM:
1167                 return lttng_abi_open_stream(file);
1168         case LTTNG_KERNEL_OLD_EVENT:
1169         {
1170                 struct lttng_kernel_event *uevent_param;
1171                 struct lttng_kernel_old_event *old_uevent_param;
1172                 int ret;
1173
1174                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1175                                 GFP_KERNEL);
1176                 if (!uevent_param) {
1177                         ret = -ENOMEM;
1178                         goto old_event_end;
1179                 }
1180                 old_uevent_param = kmalloc(
1181                                 sizeof(struct lttng_kernel_old_event),
1182                                 GFP_KERNEL);
1183                 if (!old_uevent_param) {
1184                         ret = -ENOMEM;
1185                         goto old_event_error_free_param;
1186                 }
1187                 if (copy_from_user(old_uevent_param,
1188                                 (struct lttng_kernel_old_event __user *) arg,
1189                                 sizeof(struct lttng_kernel_old_event))) {
1190                         ret = -EFAULT;
1191                         goto old_event_error_free_old_param;
1192                 }
1193
1194                 memcpy(uevent_param->name, old_uevent_param->name,
1195                                 sizeof(uevent_param->name));
1196                 uevent_param->instrumentation =
1197                         old_uevent_param->instrumentation;
1198
1199                 switch (old_uevent_param->instrumentation) {
1200                 case LTTNG_KERNEL_KPROBE:
1201                         uevent_param->u.kprobe.addr =
1202                                 old_uevent_param->u.kprobe.addr;
1203                         uevent_param->u.kprobe.offset =
1204                                 old_uevent_param->u.kprobe.offset;
1205                         memcpy(uevent_param->u.kprobe.symbol_name,
1206                                 old_uevent_param->u.kprobe.symbol_name,
1207                                 sizeof(uevent_param->u.kprobe.symbol_name));
1208                         break;
1209                 case LTTNG_KERNEL_KRETPROBE:
1210                         uevent_param->u.kretprobe.addr =
1211                                 old_uevent_param->u.kretprobe.addr;
1212                         uevent_param->u.kretprobe.offset =
1213                                 old_uevent_param->u.kretprobe.offset;
1214                         memcpy(uevent_param->u.kretprobe.symbol_name,
1215                                 old_uevent_param->u.kretprobe.symbol_name,
1216                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1217                         break;
1218                 case LTTNG_KERNEL_FUNCTION:
1219                         memcpy(uevent_param->u.ftrace.symbol_name,
1220                                         old_uevent_param->u.ftrace.symbol_name,
1221                                         sizeof(uevent_param->u.ftrace.symbol_name));
1222                         break;
1223                 default:
1224                         break;
1225                 }
1226                 ret = lttng_abi_create_event(file, uevent_param);
1227
1228 old_event_error_free_old_param:
1229                 kfree(old_uevent_param);
1230 old_event_error_free_param:
1231                 kfree(uevent_param);
1232 old_event_end:
1233                 return ret;
1234         }
1235         case LTTNG_KERNEL_EVENT:
1236         {
1237                 struct lttng_kernel_event uevent_param;
1238
1239                 if (copy_from_user(&uevent_param,
1240                                 (struct lttng_kernel_event __user *) arg,
1241                                 sizeof(uevent_param)))
1242                         return -EFAULT;
1243                 return lttng_abi_create_event(file, &uevent_param);
1244         }
1245         case LTTNG_KERNEL_OLD_CONTEXT:
1246         {
1247                 struct lttng_kernel_context *ucontext_param;
1248                 struct lttng_kernel_old_context *old_ucontext_param;
1249                 int ret;
1250
1251                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1252                                 GFP_KERNEL);
1253                 if (!ucontext_param) {
1254                         ret = -ENOMEM;
1255                         goto old_ctx_end;
1256                 }
1257                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1258                                 GFP_KERNEL);
1259                 if (!old_ucontext_param) {
1260                         ret = -ENOMEM;
1261                         goto old_ctx_error_free_param;
1262                 }
1263
1264                 if (copy_from_user(old_ucontext_param,
1265                                 (struct lttng_kernel_old_context __user *) arg,
1266                                 sizeof(struct lttng_kernel_old_context))) {
1267                         ret = -EFAULT;
1268                         goto old_ctx_error_free_old_param;
1269                 }
1270                 ucontext_param->ctx = old_ucontext_param->ctx;
1271                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1272                                 sizeof(ucontext_param->padding));
1273                 /* only type that uses the union */
1274                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1275                         ucontext_param->u.perf_counter.type =
1276                                 old_ucontext_param->u.perf_counter.type;
1277                         ucontext_param->u.perf_counter.config =
1278                                 old_ucontext_param->u.perf_counter.config;
1279                         memcpy(ucontext_param->u.perf_counter.name,
1280                                 old_ucontext_param->u.perf_counter.name,
1281                                 sizeof(ucontext_param->u.perf_counter.name));
1282                 }
1283
1284                 ret = lttng_abi_add_context(file,
1285                                 ucontext_param,
1286                                 &channel->ctx, channel->session);
1287
1288 old_ctx_error_free_old_param:
1289                 kfree(old_ucontext_param);
1290 old_ctx_error_free_param:
1291                 kfree(ucontext_param);
1292 old_ctx_end:
1293                 return ret;
1294         }
1295         case LTTNG_KERNEL_CONTEXT:
1296         {
1297                 struct lttng_kernel_context ucontext_param;
1298
1299                 if (copy_from_user(&ucontext_param,
1300                                 (struct lttng_kernel_context __user *) arg,
1301                                 sizeof(ucontext_param)))
1302                         return -EFAULT;
1303                 return lttng_abi_add_context(file,
1304                                 &ucontext_param,
1305                                 &channel->ctx, channel->session);
1306         }
1307         case LTTNG_KERNEL_OLD_ENABLE:
1308         case LTTNG_KERNEL_ENABLE:
1309                 return lttng_channel_enable(channel);
1310         case LTTNG_KERNEL_OLD_DISABLE:
1311         case LTTNG_KERNEL_DISABLE:
1312                 return lttng_channel_disable(channel);
1313         case LTTNG_KERNEL_SYSCALL_MASK:
1314                 return lttng_channel_syscall_mask(channel,
1315                         (struct lttng_kernel_syscall_mask __user *) arg);
1316         default:
1317                 return -ENOIOCTLCMD;
1318         }
1319
1320 }
1321
1322 /**
1323  *      lttng_metadata_ioctl - lttng syscall through ioctl
1324  *
1325  *      @file: the file
1326  *      @cmd: the command
1327  *      @arg: command arg
1328  *
1329  *      This ioctl implements lttng commands:
1330  *      LTTNG_KERNEL_STREAM
1331  *              Returns an event stream file descriptor or failure.
1332  *
1333  * Channel and event file descriptors also hold a reference on the session.
1334  */
1335 static
1336 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1337 {
1338         switch (cmd) {
1339         case LTTNG_KERNEL_OLD_STREAM:
1340         case LTTNG_KERNEL_STREAM:
1341                 return lttng_abi_open_metadata_stream(file);
1342         default:
1343                 return -ENOIOCTLCMD;
1344         }
1345 }
1346
1347 /**
1348  *      lttng_channel_poll - lttng stream addition/removal monitoring
1349  *
1350  *      @file: the file
1351  *      @wait: poll table
1352  */
1353 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1354 {
1355         struct lttng_channel *channel = file->private_data;
1356         unsigned int mask = 0;
1357
1358         if (file->f_mode & FMODE_READ) {
1359                 poll_wait_set_exclusive(wait);
1360                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1361                           wait);
1362
1363                 if (channel->ops->is_disabled(channel->chan))
1364                         return POLLERR;
1365                 if (channel->ops->is_finalized(channel->chan))
1366                         return POLLHUP;
1367                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1368                         return POLLIN | POLLRDNORM;
1369                 return 0;
1370         }
1371         return mask;
1372
1373 }
1374
1375 static
1376 int lttng_channel_release(struct inode *inode, struct file *file)
1377 {
1378         struct lttng_channel *channel = file->private_data;
1379
1380         if (channel)
1381                 fput(channel->session->file);
1382         return 0;
1383 }
1384
1385 static
1386 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1387 {
1388         struct lttng_channel *channel = file->private_data;
1389
1390         if (channel) {
1391                 fput(channel->session->file);
1392                 lttng_metadata_channel_destroy(channel);
1393         }
1394
1395         return 0;
1396 }
1397
1398 static const struct file_operations lttng_channel_fops = {
1399         .owner = THIS_MODULE,
1400         .release = lttng_channel_release,
1401         .poll = lttng_channel_poll,
1402         .unlocked_ioctl = lttng_channel_ioctl,
1403 #ifdef CONFIG_COMPAT
1404         .compat_ioctl = lttng_channel_ioctl,
1405 #endif
1406 };
1407
1408 static const struct file_operations lttng_metadata_fops = {
1409         .owner = THIS_MODULE,
1410         .release = lttng_metadata_channel_release,
1411         .unlocked_ioctl = lttng_metadata_ioctl,
1412 #ifdef CONFIG_COMPAT
1413         .compat_ioctl = lttng_metadata_ioctl,
1414 #endif
1415 };
1416
1417 /**
1418  *      lttng_event_ioctl - lttng syscall through ioctl
1419  *
1420  *      @file: the file
1421  *      @cmd: the command
1422  *      @arg: command arg
1423  *
1424  *      This ioctl implements lttng commands:
1425  *      LTTNG_KERNEL_CONTEXT
1426  *              Prepend a context field to each record of this event
1427  *      LTTNG_KERNEL_ENABLE
1428  *              Enable recording for this event (weak enable)
1429  *      LTTNG_KERNEL_DISABLE
1430  *              Disable recording for this event (strong disable)
1431  */
1432 static
1433 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1434 {
1435         struct lttng_event *event;
1436         struct lttng_enabler *enabler;
1437         enum lttng_event_type *evtype = file->private_data;
1438
1439         switch (cmd) {
1440         case LTTNG_KERNEL_OLD_CONTEXT:
1441         {
1442                 /* Not implemented */
1443                 return -ENOSYS;
1444         }
1445         case LTTNG_KERNEL_CONTEXT:
1446         {
1447                 /* Not implemented */
1448                 return -ENOSYS;
1449         }
1450         case LTTNG_KERNEL_OLD_ENABLE:
1451         case LTTNG_KERNEL_ENABLE:
1452                 switch (*evtype) {
1453                 case LTTNG_TYPE_EVENT:
1454                         event = file->private_data;
1455                         return lttng_event_enable(event);
1456                 case LTTNG_TYPE_ENABLER:
1457                         enabler = file->private_data;
1458                         return lttng_enabler_enable(enabler);
1459                 default:
1460                         WARN_ON_ONCE(1);
1461                         return -ENOSYS;
1462                 }
1463         case LTTNG_KERNEL_OLD_DISABLE:
1464         case LTTNG_KERNEL_DISABLE:
1465                 switch (*evtype) {
1466                 case LTTNG_TYPE_EVENT:
1467                         event = file->private_data;
1468                         return lttng_event_disable(event);
1469                 case LTTNG_TYPE_ENABLER:
1470                         enabler = file->private_data;
1471                         return lttng_enabler_disable(enabler);
1472                 default:
1473                         WARN_ON_ONCE(1);
1474                         return -ENOSYS;
1475                 }
1476         case LTTNG_KERNEL_FILTER:
1477                 switch (*evtype) {
1478                 case LTTNG_TYPE_EVENT:
1479                         return -EINVAL;
1480                 case LTTNG_TYPE_ENABLER:
1481                 {
1482                         enabler = file->private_data;
1483                         return lttng_enabler_attach_bytecode(enabler,
1484                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1485                 }
1486
1487                 }
1488         default:
1489                 return -ENOIOCTLCMD;
1490         }
1491 }
1492
1493 static
1494 int lttng_event_release(struct inode *inode, struct file *file)
1495 {
1496         struct lttng_event *event;
1497         struct lttng_enabler *enabler;
1498         enum lttng_event_type *evtype = file->private_data;
1499
1500         if (!evtype)
1501                 return 0;
1502
1503         switch (*evtype) {
1504         case LTTNG_TYPE_EVENT:
1505                 event = file->private_data;
1506                 if (event)
1507                         fput(event->chan->file);
1508                 break;
1509         case LTTNG_TYPE_ENABLER:
1510                 enabler = file->private_data;
1511                 if (enabler)
1512                         fput(enabler->chan->file);
1513                 break;
1514         default:
1515                 WARN_ON_ONCE(1);
1516                 break;
1517         }
1518
1519         return 0;
1520 }
1521
1522 /* TODO: filter control ioctl */
1523 static const struct file_operations lttng_event_fops = {
1524         .owner = THIS_MODULE,
1525         .release = lttng_event_release,
1526         .unlocked_ioctl = lttng_event_ioctl,
1527 #ifdef CONFIG_COMPAT
1528         .compat_ioctl = lttng_event_ioctl,
1529 #endif
1530 };
1531
1532 static int put_u64(uint64_t val, unsigned long arg)
1533 {
1534         return put_user(val, (uint64_t __user *) arg);
1535 }
1536
1537 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1538                 unsigned int cmd, unsigned long arg)
1539 {
1540         struct lib_ring_buffer *buf = filp->private_data;
1541         struct channel *chan = buf->backend.chan;
1542         const struct lib_ring_buffer_config *config = &chan->backend.config;
1543         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1544         int ret;
1545
1546         if (atomic_read(&chan->record_disabled))
1547                 return -EIO;
1548
1549         switch (cmd) {
1550         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1551         {
1552                 uint64_t ts;
1553
1554                 ret = ops->timestamp_begin(config, buf, &ts);
1555                 if (ret < 0)
1556                         goto error;
1557                 return put_u64(ts, arg);
1558         }
1559         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1560         {
1561                 uint64_t ts;
1562
1563                 ret = ops->timestamp_end(config, buf, &ts);
1564                 if (ret < 0)
1565                         goto error;
1566                 return put_u64(ts, arg);
1567         }
1568         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1569         {
1570                 uint64_t ed;
1571
1572                 ret = ops->events_discarded(config, buf, &ed);
1573                 if (ret < 0)
1574                         goto error;
1575                 return put_u64(ed, arg);
1576         }
1577         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1578         {
1579                 uint64_t cs;
1580
1581                 ret = ops->content_size(config, buf, &cs);
1582                 if (ret < 0)
1583                         goto error;
1584                 return put_u64(cs, arg);
1585         }
1586         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1587         {
1588                 uint64_t ps;
1589
1590                 ret = ops->packet_size(config, buf, &ps);
1591                 if (ret < 0)
1592                         goto error;
1593                 return put_u64(ps, arg);
1594         }
1595         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1596         {
1597                 uint64_t si;
1598
1599                 ret = ops->stream_id(config, buf, &si);
1600                 if (ret < 0)
1601                         goto error;
1602                 return put_u64(si, arg);
1603         }
1604         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1605         {
1606                 uint64_t ts;
1607
1608                 ret = ops->current_timestamp(config, buf, &ts);
1609                 if (ret < 0)
1610                         goto error;
1611                 return put_u64(ts, arg);
1612         }
1613         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1614         {
1615                 uint64_t seq;
1616
1617                 ret = ops->sequence_number(config, buf, &seq);
1618                 if (ret < 0)
1619                         goto error;
1620                 return put_u64(seq, arg);
1621         }
1622         case LTTNG_RING_BUFFER_INSTANCE_ID:
1623         {
1624                 uint64_t id;
1625
1626                 ret = ops->instance_id(config, buf, &id);
1627                 if (ret < 0)
1628                         goto error;
1629                 return put_u64(id, arg);
1630         }
1631         default:
1632                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1633                                 cmd, arg);
1634         }
1635
1636 error:
1637         return -ENOSYS;
1638 }
1639
1640 #ifdef CONFIG_COMPAT
1641 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1642                 unsigned int cmd, unsigned long arg)
1643 {
1644         struct lib_ring_buffer *buf = filp->private_data;
1645         struct channel *chan = buf->backend.chan;
1646         const struct lib_ring_buffer_config *config = &chan->backend.config;
1647         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1648         int ret;
1649
1650         if (atomic_read(&chan->record_disabled))
1651                 return -EIO;
1652
1653         switch (cmd) {
1654         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1655         {
1656                 uint64_t ts;
1657
1658                 ret = ops->timestamp_begin(config, buf, &ts);
1659                 if (ret < 0)
1660                         goto error;
1661                 return put_u64(ts, arg);
1662         }
1663         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1664         {
1665                 uint64_t ts;
1666
1667                 ret = ops->timestamp_end(config, buf, &ts);
1668                 if (ret < 0)
1669                         goto error;
1670                 return put_u64(ts, arg);
1671         }
1672         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1673         {
1674                 uint64_t ed;
1675
1676                 ret = ops->events_discarded(config, buf, &ed);
1677                 if (ret < 0)
1678                         goto error;
1679                 return put_u64(ed, arg);
1680         }
1681         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1682         {
1683                 uint64_t cs;
1684
1685                 ret = ops->content_size(config, buf, &cs);
1686                 if (ret < 0)
1687                         goto error;
1688                 return put_u64(cs, arg);
1689         }
1690         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1691         {
1692                 uint64_t ps;
1693
1694                 ret = ops->packet_size(config, buf, &ps);
1695                 if (ret < 0)
1696                         goto error;
1697                 return put_u64(ps, arg);
1698         }
1699         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1700         {
1701                 uint64_t si;
1702
1703                 ret = ops->stream_id(config, buf, &si);
1704                 if (ret < 0)
1705                         goto error;
1706                 return put_u64(si, arg);
1707         }
1708         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1709         {
1710                 uint64_t ts;
1711
1712                 ret = ops->current_timestamp(config, buf, &ts);
1713                 if (ret < 0)
1714                         goto error;
1715                 return put_u64(ts, arg);
1716         }
1717         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1718         {
1719                 uint64_t seq;
1720
1721                 ret = ops->sequence_number(config, buf, &seq);
1722                 if (ret < 0)
1723                         goto error;
1724                 return put_u64(seq, arg);
1725         }
1726         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1727         {
1728                 uint64_t id;
1729
1730                 ret = ops->instance_id(config, buf, &id);
1731                 if (ret < 0)
1732                         goto error;
1733                 return put_u64(id, arg);
1734         }
1735         default:
1736                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1737                                 cmd, arg);
1738         }
1739
1740 error:
1741         return -ENOSYS;
1742 }
1743 #endif /* CONFIG_COMPAT */
1744
1745 static void lttng_stream_override_ring_buffer_fops(void)
1746 {
1747         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1748         lttng_stream_ring_buffer_file_operations.open =
1749                 lib_ring_buffer_file_operations.open;
1750         lttng_stream_ring_buffer_file_operations.release =
1751                 lib_ring_buffer_file_operations.release;
1752         lttng_stream_ring_buffer_file_operations.poll =
1753                 lib_ring_buffer_file_operations.poll;
1754         lttng_stream_ring_buffer_file_operations.splice_read =
1755                 lib_ring_buffer_file_operations.splice_read;
1756         lttng_stream_ring_buffer_file_operations.mmap =
1757                 lib_ring_buffer_file_operations.mmap;
1758         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1759                 lttng_stream_ring_buffer_ioctl;
1760         lttng_stream_ring_buffer_file_operations.llseek =
1761                 lib_ring_buffer_file_operations.llseek;
1762 #ifdef CONFIG_COMPAT
1763         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1764                 lttng_stream_ring_buffer_compat_ioctl;
1765 #endif
1766 }
1767
1768 int __init lttng_abi_init(void)
1769 {
1770         int ret = 0;
1771
1772         wrapper_vmalloc_sync_all();
1773         lttng_clock_ref();
1774         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1775                                         &lttng_fops, NULL);
1776
1777         if (!lttng_proc_dentry) {
1778                 printk(KERN_ERR "Error creating LTTng control file\n");
1779                 ret = -ENOMEM;
1780                 goto error;
1781         }
1782         lttng_stream_override_ring_buffer_fops();
1783         return 0;
1784
1785 error:
1786         lttng_clock_unref();
1787         return ret;
1788 }
1789
1790 /* No __exit annotation because used by init error path too. */
1791 void lttng_abi_exit(void)
1792 {
1793         lttng_clock_unref();
1794         if (lttng_proc_dentry)
1795                 remove_proc_entry("lttng", NULL);
1796 }