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 <lttng-tp-mempool.h>
  60 #include <lib/ringbuffer/frontend_types.h>
  61
  62 /*
  63  * This is LTTng's own personal way to create a system call as an external
  64  * module. We use ioctl() on /proc/lttng.
  65  */
  66
  67 static struct proc_dir_entry *lttng_proc_dentry;
  68 static const struct file_operations lttng_fops;
  69 static const struct file_operations lttng_session_fops;
  70 static const struct file_operations lttng_channel_fops;
  71 static const struct file_operations lttng_metadata_fops;
  72 static const struct file_operations lttng_event_fops;
  73 static struct file_operations lttng_stream_ring_buffer_file_operations;
  74
  75 static int put_u64(uint64_t val, unsigned long arg);
  76
  77 /*
  78  * Teardown management: opened file descriptors keep a refcount on the module,
  79  * so it can only exit when all file descriptors are closed.
  80  */
  81
  82 static
  83 int lttng_abi_create_session(void)
  84 {
  85         struct lttng_session *session;
  86         struct file *session_file;
  87         int session_fd, ret;
  88
  89         session = lttng_session_create();
  90         if (!session)
  91                 return -ENOMEM;
  92         session_fd = lttng_get_unused_fd();
  93         if (session_fd < 0) {
  94                 ret = session_fd;
  95                 goto fd_error;
  96         }
  97         session_file = anon_inode_getfile("[lttng_session]",
  98                                           &lttng_session_fops,
  99                                           session, O_RDWR);
 100         if (IS_ERR(session_file)) {
 101                 ret = PTR_ERR(session_file);
 102                 goto file_error;
 103         }
 104         session->file = session_file;
 105         fd_install(session_fd, session_file);
 106         return session_fd;
 107
 108 file_error:
 109         put_unused_fd(session_fd);
 110 fd_error:
 111         lttng_session_destroy(session);
 112         return ret;
 113 }
 114
 115 static
 116 int lttng_abi_tracepoint_list(void)
 117 {
 118         struct file *tracepoint_list_file;
 119         int file_fd, ret;
 120
 121         file_fd = lttng_get_unused_fd();
 122         if (file_fd < 0) {
 123                 ret = file_fd;
 124                 goto fd_error;
 125         }
 126
 127         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 128                                           &lttng_tracepoint_list_fops,
 129                                           NULL, O_RDWR);
 130         if (IS_ERR(tracepoint_list_file)) {
 131                 ret = PTR_ERR(tracepoint_list_file);
 132                 goto file_error;
 133         }
 134         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 135         if (ret < 0)
 136                 goto open_error;
 137         fd_install(file_fd, tracepoint_list_file);
 138         return file_fd;
 139
 140 open_error:
 141         fput(tracepoint_list_file);
 142 file_error:
 143         put_unused_fd(file_fd);
 144 fd_error:
 145         return ret;
 146 }
 147
 148 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 149 static inline
 150 int lttng_abi_syscall_list(void)
 151 {
 152         return -ENOSYS;
 153 }
 154 #else
 155 static
 156 int lttng_abi_syscall_list(void)
 157 {
 158         struct file *syscall_list_file;
 159         int file_fd, ret;
 160
 161         file_fd = lttng_get_unused_fd();
 162         if (file_fd < 0) {
 163                 ret = file_fd;
 164                 goto fd_error;
 165         }
 166
 167         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 168                                           &lttng_syscall_list_fops,
 169                                           NULL, O_RDWR);
 170         if (IS_ERR(syscall_list_file)) {
 171                 ret = PTR_ERR(syscall_list_file);
 172                 goto file_error;
 173         }
 174         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 175         if (ret < 0)
 176                 goto open_error;
 177         fd_install(file_fd, syscall_list_file);
 178         return file_fd;
 179
 180 open_error:
 181         fput(syscall_list_file);
 182 file_error:
 183         put_unused_fd(file_fd);
 184 fd_error:
 185         return ret;
 186 }
 187 #endif
 188
 189 static
 190 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 191 {
 192         v->major = LTTNG_MODULES_MAJOR_VERSION;
 193         v->minor = LTTNG_MODULES_MINOR_VERSION;
 194         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 195 }
 196
 197 static
 198 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 199 {
 200         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 201         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 202 }
 203
 204 static
 205 long lttng_abi_add_context(struct file *file,
 206         struct lttng_kernel_context *context_param,
 207         struct lttng_ctx **ctx, struct lttng_session *session)
 208 {
 209
 210         if (session->been_active)
 211                 return -EPERM;
 212
 213         switch (context_param->ctx) {
 214         case LTTNG_KERNEL_CONTEXT_PID:
 215                 return lttng_add_pid_to_ctx(ctx);
 216         case LTTNG_KERNEL_CONTEXT_PRIO:
 217                 return lttng_add_prio_to_ctx(ctx);
 218         case LTTNG_KERNEL_CONTEXT_NICE:
 219                 return lttng_add_nice_to_ctx(ctx);
 220         case LTTNG_KERNEL_CONTEXT_VPID:
 221                 return lttng_add_vpid_to_ctx(ctx);
 222         case LTTNG_KERNEL_CONTEXT_TID:
 223                 return lttng_add_tid_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_VTID:
 225                 return lttng_add_vtid_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_PPID:
 227                 return lttng_add_ppid_to_ctx(ctx);
 228         case LTTNG_KERNEL_CONTEXT_VPPID:
 229                 return lttng_add_vppid_to_ctx(ctx);
 230         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 231                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 232                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 233                                 context_param->u.perf_counter.config,
 234                                 context_param->u.perf_counter.name,
 235                                 ctx);
 236         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 237                 return lttng_add_procname_to_ctx(ctx);
 238         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 239                 return lttng_add_hostname_to_ctx(ctx);
 240         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 241                 return lttng_add_cpu_id_to_ctx(ctx);
 242         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 243                 return lttng_add_interruptible_to_ctx(ctx);
 244         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 245                 return lttng_add_need_reschedule_to_ctx(ctx);
 246         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 247                 return lttng_add_preemptible_to_ctx(ctx);
 248         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 249                 return lttng_add_migratable_to_ctx(ctx);
 250         default:
 251                 return -EINVAL;
 252         }
 253 }
 254
 255 /**
 256  *      lttng_ioctl - lttng syscall through ioctl
 257  *
 258  *      @file: the file
 259  *      @cmd: the command
 260  *      @arg: command arg
 261  *
 262  *      This ioctl implements lttng commands:
 263  *      LTTNG_KERNEL_SESSION
 264  *              Returns a LTTng trace session file descriptor
 265  *      LTTNG_KERNEL_TRACER_VERSION
 266  *              Returns the LTTng kernel tracer version
 267  *      LTTNG_KERNEL_TRACEPOINT_LIST
 268  *              Returns a file descriptor listing available tracepoints
 269  *      LTTNG_KERNEL_WAIT_QUIESCENT
 270  *              Returns after all previously running probes have completed
 271  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 272  *              Returns the LTTng kernel tracer ABI version
 273  *
 274  * The returned session will be deleted when its file descriptor is closed.
 275  */
 276 static
 277 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 278 {
 279         switch (cmd) {
 280         case LTTNG_KERNEL_OLD_SESSION:
 281         case LTTNG_KERNEL_SESSION:
 282                 return lttng_abi_create_session();
 283         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 284         {
 285                 struct lttng_kernel_tracer_version v;
 286                 struct lttng_kernel_old_tracer_version oldv;
 287                 struct lttng_kernel_old_tracer_version *uversion =
 288                         (struct lttng_kernel_old_tracer_version __user *) arg;
 289
 290                 lttng_abi_tracer_version(&v);
 291                 oldv.major = v.major;
 292                 oldv.minor = v.minor;
 293                 oldv.patchlevel = v.patchlevel;
 294
 295                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 296                         return -EFAULT;
 297                 return 0;
 298         }
 299         case LTTNG_KERNEL_TRACER_VERSION:
 300         {
 301                 struct lttng_kernel_tracer_version version;
 302                 struct lttng_kernel_tracer_version *uversion =
 303                         (struct lttng_kernel_tracer_version __user *) arg;
 304
 305                 lttng_abi_tracer_version(&version);
 306
 307                 if (copy_to_user(uversion, &version, sizeof(version)))
 308                         return -EFAULT;
 309                 return 0;
 310         }
 311         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 312         {
 313                 struct lttng_kernel_tracer_abi_version version;
 314                 struct lttng_kernel_tracer_abi_version *uversion =
 315                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 316
 317                 lttng_abi_tracer_abi_version(&version);
 318
 319                 if (copy_to_user(uversion, &version, sizeof(version)))
 320                         return -EFAULT;
 321                 return 0;
 322         }
 323         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 324         case LTTNG_KERNEL_TRACEPOINT_LIST:
 325                 return lttng_abi_tracepoint_list();
 326         case LTTNG_KERNEL_SYSCALL_LIST:
 327                 return lttng_abi_syscall_list();
 328         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 329         case LTTNG_KERNEL_WAIT_QUIESCENT:
 330                 synchronize_trace();
 331                 return 0;
 332         case LTTNG_KERNEL_OLD_CALIBRATE:
 333         {
 334                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 335                         (struct lttng_kernel_old_calibrate __user *) arg;
 336                 struct lttng_kernel_old_calibrate old_calibrate;
 337                 struct lttng_kernel_calibrate calibrate;
 338                 int ret;
 339
 340                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 341                         return -EFAULT;
 342                 calibrate.type = old_calibrate.type;
 343                 ret = lttng_calibrate(&calibrate);
 344                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 345                         return -EFAULT;
 346                 return ret;
 347         }
 348         case LTTNG_KERNEL_CALIBRATE:
 349         {
 350                 struct lttng_kernel_calibrate __user *ucalibrate =
 351                         (struct lttng_kernel_calibrate __user *) arg;
 352                 struct lttng_kernel_calibrate calibrate;
 353                 int ret;
 354
 355                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 356                         return -EFAULT;
 357                 ret = lttng_calibrate(&calibrate);
 358                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 359                         return -EFAULT;
 360                 return ret;
 361         }
 362         default:
 363                 return -ENOIOCTLCMD;
 364         }
 365 }
 366
 367 static const struct file_operations lttng_fops = {
 368         .owner = THIS_MODULE,
 369         .unlocked_ioctl = lttng_ioctl,
 370 #ifdef CONFIG_COMPAT
 371         .compat_ioctl = lttng_ioctl,
 372 #endif
 373 };
 374
 375 static
 376 int lttng_abi_create_channel(struct file *session_file,
 377                              struct lttng_kernel_channel *chan_param,
 378                              enum channel_type channel_type)
 379 {
 380         struct lttng_session *session = session_file->private_data;
 381         const struct file_operations *fops = NULL;
 382         const char *transport_name;
 383         struct lttng_channel *chan;
 384         struct file *chan_file;
 385         int chan_fd;
 386         int ret = 0;
 387
 388         chan_fd = lttng_get_unused_fd();
 389         if (chan_fd < 0) {
 390                 ret = chan_fd;
 391                 goto fd_error;
 392         }
 393         switch (channel_type) {
 394         case PER_CPU_CHANNEL:
 395                 fops = &lttng_channel_fops;
 396                 break;
 397         case METADATA_CHANNEL:
 398                 fops = &lttng_metadata_fops;
 399                 break;
 400         }
 401
 402         chan_file = anon_inode_getfile("[lttng_channel]",
 403                                        fops,
 404                                        NULL, O_RDWR);
 405         if (IS_ERR(chan_file)) {
 406                 ret = PTR_ERR(chan_file);
 407                 goto file_error;
 408         }
 409         switch (channel_type) {
 410         case PER_CPU_CHANNEL:
 411                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 412                         transport_name = chan_param->overwrite ?
 413                                 "relay-overwrite" : "relay-discard";
 414                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 415                         transport_name = chan_param->overwrite ?
 416                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 417                 } else {
 418                         return -EINVAL;
 419                 }
 420                 break;
 421         case METADATA_CHANNEL:
 422                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 423                         transport_name = "relay-metadata";
 424                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 425                         transport_name = "relay-metadata-mmap";
 426                 else
 427                         return -EINVAL;
 428                 break;
 429         default:
 430                 transport_name = "<unknown>";
 431                 break;
 432         }
 433         if (!atomic_long_add_unless(&session_file->f_count, 1, LONG_MAX)) {
 434                 ret = -EOVERFLOW;
 435                 goto refcount_error;
 436         }
 437         /*
 438          * We tolerate no failure path after channel creation. It will stay
 439          * invariant for the rest of the session.
 440          */
 441         chan = lttng_channel_create(session, transport_name, NULL,
 442                                   chan_param->subbuf_size,
 443                                   chan_param->num_subbuf,
 444                                   chan_param->switch_timer_interval,
 445                                   chan_param->read_timer_interval,
 446                                   channel_type);
 447         if (!chan) {
 448                 ret = -EINVAL;
 449                 goto chan_error;
 450         }
 451         chan->file = chan_file;
 452         chan_file->private_data = chan;
 453         fd_install(chan_fd, chan_file);
 454
 455         return chan_fd;
 456
 457 chan_error:
 458         atomic_long_dec(&session_file->f_count);
 459 refcount_error:
 460         fput(chan_file);
 461 file_error:
 462         put_unused_fd(chan_fd);
 463 fd_error:
 464         return ret;
 465 }
 466
 467 /**
 468  *      lttng_session_ioctl - lttng session fd ioctl
 469  *
 470  *      @file: the file
 471  *      @cmd: the command
 472  *      @arg: command arg
 473  *
 474  *      This ioctl implements lttng commands:
 475  *      LTTNG_KERNEL_CHANNEL
 476  *              Returns a LTTng channel file descriptor
 477  *      LTTNG_KERNEL_ENABLE
 478  *              Enables tracing for a session (weak enable)
 479  *      LTTNG_KERNEL_DISABLE
 480  *              Disables tracing for a session (strong disable)
 481  *      LTTNG_KERNEL_METADATA
 482  *              Returns a LTTng metadata file descriptor
 483  *      LTTNG_KERNEL_SESSION_TRACK_PID
 484  *              Add PID to session tracker
 485  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 486  *              Remove PID from session tracker
 487  *
 488  * The returned channel will be deleted when its file descriptor is closed.
 489  */
 490 static
 491 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 492 {
 493         struct lttng_session *session = file->private_data;
 494
 495         switch (cmd) {
 496         case LTTNG_KERNEL_OLD_CHANNEL:
 497         {
 498                 struct lttng_kernel_channel chan_param;
 499                 struct lttng_kernel_old_channel old_chan_param;
 500
 501                 if (copy_from_user(&old_chan_param,
 502                                 (struct lttng_kernel_old_channel __user *) arg,
 503                                 sizeof(struct lttng_kernel_old_channel)))
 504                         return -EFAULT;
 505                 chan_param.overwrite = old_chan_param.overwrite;
 506                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 507                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 508                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 509                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 510                 chan_param.output = old_chan_param.output;
 511
 512                 return lttng_abi_create_channel(file, &chan_param,
 513                                 PER_CPU_CHANNEL);
 514         }
 515         case LTTNG_KERNEL_CHANNEL:
 516         {
 517                 struct lttng_kernel_channel chan_param;
 518
 519                 if (copy_from_user(&chan_param,
 520                                 (struct lttng_kernel_channel __user *) arg,
 521                                 sizeof(struct lttng_kernel_channel)))
 522                         return -EFAULT;
 523                 return lttng_abi_create_channel(file, &chan_param,
 524                                 PER_CPU_CHANNEL);
 525         }
 526         case LTTNG_KERNEL_OLD_SESSION_START:
 527         case LTTNG_KERNEL_OLD_ENABLE:
 528         case LTTNG_KERNEL_SESSION_START:
 529         case LTTNG_KERNEL_ENABLE:
 530                 return lttng_session_enable(session);
 531         case LTTNG_KERNEL_OLD_SESSION_STOP:
 532         case LTTNG_KERNEL_OLD_DISABLE:
 533         case LTTNG_KERNEL_SESSION_STOP:
 534         case LTTNG_KERNEL_DISABLE:
 535                 return lttng_session_disable(session);
 536         case LTTNG_KERNEL_OLD_METADATA:
 537         {
 538                 struct lttng_kernel_channel chan_param;
 539                 struct lttng_kernel_old_channel old_chan_param;
 540
 541                 if (copy_from_user(&old_chan_param,
 542                                 (struct lttng_kernel_old_channel __user *) arg,
 543                                 sizeof(struct lttng_kernel_old_channel)))
 544                         return -EFAULT;
 545                 chan_param.overwrite = old_chan_param.overwrite;
 546                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 547                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 548                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 549                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 550                 chan_param.output = old_chan_param.output;
 551
 552                 return lttng_abi_create_channel(file, &chan_param,
 553                                 METADATA_CHANNEL);
 554         }
 555         case LTTNG_KERNEL_METADATA:
 556         {
 557                 struct lttng_kernel_channel chan_param;
 558
 559                 if (copy_from_user(&chan_param,
 560                                         (struct lttng_kernel_channel __user *) arg,
 561                                         sizeof(struct lttng_kernel_channel)))
 562                         return -EFAULT;
 563                 return lttng_abi_create_channel(file, &chan_param,
 564                                 METADATA_CHANNEL);
 565         }
 566         case LTTNG_KERNEL_SESSION_TRACK_PID:
 567                 return lttng_session_track_pid(session, (int) arg);
 568         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 569                 return lttng_session_untrack_pid(session, (int) arg);
 570         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 571                 return lttng_session_list_tracker_pids(session);
 572         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 573                 return lttng_session_metadata_regenerate(session);
 574         case LTTNG_KERNEL_SESSION_STATEDUMP:
 575                 return lttng_session_statedump(session);
 576         default:
 577                 return -ENOIOCTLCMD;
 578         }
 579 }
 580
 581 /*
 582  * Called when the last file reference is dropped.
 583  *
 584  * Big fat note: channels and events are invariant for the whole session after
 585  * their creation. So this session destruction also destroys all channel and
 586  * event structures specific to this session (they are not destroyed when their
 587  * individual file is released).
 588  */
 589 static
 590 int lttng_session_release(struct inode *inode, struct file *file)
 591 {
 592         struct lttng_session *session = file->private_data;
 593
 594         if (session)
 595                 lttng_session_destroy(session);
 596         return 0;
 597 }
 598
 599 static const struct file_operations lttng_session_fops = {
 600         .owner = THIS_MODULE,
 601         .release = lttng_session_release,
 602         .unlocked_ioctl = lttng_session_ioctl,
 603 #ifdef CONFIG_COMPAT
 604         .compat_ioctl = lttng_session_ioctl,
 605 #endif
 606 };
 607
 608 /**
 609  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 610  *      @filp: the file
 611  *      @wait: poll table
 612  *
 613  *      Handles the poll operations for the metadata channels.
 614  */
 615 static
 616 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 617                 poll_table *wait)
 618 {
 619         struct lttng_metadata_stream *stream = filp->private_data;
 620         struct lib_ring_buffer *buf = stream->priv;
 621         int finalized;
 622         unsigned int mask = 0;
 623
 624         if (filp->f_mode & FMODE_READ) {
 625                 poll_wait_set_exclusive(wait);
 626                 poll_wait(filp, &stream->read_wait, wait);
 627
 628                 finalized = stream->finalized;
 629
 630                 /*
 631                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 632                  * ordering finalized load before offsets loads.
 633                  */
 634                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 635
 636                 if (finalized)
 637                         mask |= POLLHUP;
 638
 639                 mutex_lock(&stream->metadata_cache->lock);
 640                 if (stream->metadata_cache->metadata_written >
 641                                 stream->metadata_out)
 642                         mask |= POLLIN;
 643                 mutex_unlock(&stream->metadata_cache->lock);
 644         }
 645
 646         return mask;
 647 }
 648
 649 static
 650 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 651                 unsigned int cmd, unsigned long arg)
 652 {
 653         struct lttng_metadata_stream *stream = filp->private_data;
 654
 655         stream->metadata_out = stream->metadata_in;
 656 }
 657
 658 static
 659 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 660                 unsigned int cmd, unsigned long arg)
 661 {
 662         int ret;
 663         struct lttng_metadata_stream *stream = filp->private_data;
 664         struct lib_ring_buffer *buf = stream->priv;
 665
 666         switch (cmd) {
 667         case RING_BUFFER_GET_NEXT_SUBBUF:
 668         {
 669                 struct lttng_metadata_stream *stream = filp->private_data;
 670                 struct lib_ring_buffer *buf = stream->priv;
 671                 struct channel *chan = buf->backend.chan;
 672
 673                 ret = lttng_metadata_output_channel(stream, chan);
 674                 if (ret > 0) {
 675                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 676                         ret = 0;
 677                 } else if (ret < 0)
 678                         goto err;
 679                 break;
 680         }
 681         case RING_BUFFER_GET_SUBBUF:
 682         {
 683                 /*
 684                  * Random access is not allowed for metadata channel.
 685                  */
 686                 return -ENOSYS;
 687         }
 688         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 689         case RING_BUFFER_FLUSH:
 690         {
 691                 struct lttng_metadata_stream *stream = filp->private_data;
 692                 struct lib_ring_buffer *buf = stream->priv;
 693                 struct channel *chan = buf->backend.chan;
 694
 695                 /*
 696                  * Before doing the actual ring buffer flush, write up to one
 697                  * packet of metadata in the ring buffer.
 698                  */
 699                 ret = lttng_metadata_output_channel(stream, chan);
 700                 if (ret < 0)
 701                         goto err;
 702                 break;
 703         }
 704         case RING_BUFFER_GET_METADATA_VERSION:
 705         {
 706                 struct lttng_metadata_stream *stream = filp->private_data;
 707
 708                 return put_u64(stream->version, arg);
 709         }
 710         default:
 711                 break;
 712         }
 713         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 714
 715         /* Performing lib ring buffer ioctl after our own. */
 716         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 717         if (ret < 0)
 718                 goto err;
 719
 720         switch (cmd) {
 721         case RING_BUFFER_PUT_NEXT_SUBBUF:
 722         {
 723                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 724                                 cmd, arg);
 725                 break;
 726         }
 727         default:
 728                 break;
 729         }
 730 err:
 731         return ret;
 732 }
 733
 734 #ifdef CONFIG_COMPAT
 735 static
 736 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 737                 unsigned int cmd, unsigned long arg)
 738 {
 739         int ret;
 740         struct lttng_metadata_stream *stream = filp->private_data;
 741         struct lib_ring_buffer *buf = stream->priv;
 742
 743         switch (cmd) {
 744         case RING_BUFFER_GET_NEXT_SUBBUF:
 745         {
 746                 struct lttng_metadata_stream *stream = filp->private_data;
 747                 struct lib_ring_buffer *buf = stream->priv;
 748                 struct channel *chan = buf->backend.chan;
 749
 750                 ret = lttng_metadata_output_channel(stream, chan);
 751                 if (ret > 0) {
 752                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 753                         ret = 0;
 754                 } else if (ret < 0)
 755                         goto err;
 756                 break;
 757         }
 758         case RING_BUFFER_GET_SUBBUF:
 759         {
 760                 /*
 761                  * Random access is not allowed for metadata channel.
 762                  */
 763                 return -ENOSYS;
 764         }
 765         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 766         case RING_BUFFER_FLUSH:
 767         {
 768                 struct lttng_metadata_stream *stream = filp->private_data;
 769                 struct lib_ring_buffer *buf = stream->priv;
 770                 struct channel *chan = buf->backend.chan;
 771
 772                 /*
 773                  * Before doing the actual ring buffer flush, write up to one
 774                  * packet of metadata in the ring buffer.
 775                  */
 776                 ret = lttng_metadata_output_channel(stream, chan);
 777                 if (ret < 0)
 778                         goto err;
 779                 break;
 780         }
 781         case RING_BUFFER_GET_METADATA_VERSION:
 782         {
 783                 struct lttng_metadata_stream *stream = filp->private_data;
 784
 785                 return put_u64(stream->version, arg);
 786         }
 787         default:
 788                 break;
 789         }
 790         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 791
 792         /* Performing lib ring buffer ioctl after our own. */
 793         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 794         if (ret < 0)
 795                 goto err;
 796
 797         switch (cmd) {
 798         case RING_BUFFER_PUT_NEXT_SUBBUF:
 799         {
 800                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 801                                 cmd, arg);
 802                 break;
 803         }
 804         default:
 805                 break;
 806         }
 807 err:
 808         return ret;
 809 }
 810 #endif
 811
 812 /*
 813  * This is not used by anonymous file descriptors. This code is left
 814  * there if we ever want to implement an inode with open() operation.
 815  */
 816 static
 817 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 818 {
 819         struct lttng_metadata_stream *stream = inode->i_private;
 820         struct lib_ring_buffer *buf = stream->priv;
 821
 822         file->private_data = buf;
 823         /*
 824          * Since life-time of metadata cache differs from that of
 825          * session, we need to keep our own reference on the transport.
 826          */
 827         if (!try_module_get(stream->transport->owner)) {
 828                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 829                 return -EBUSY;
 830         }
 831         return lib_ring_buffer_open(inode, file, buf);
 832 }
 833
 834 static
 835 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 836 {
 837         struct lttng_metadata_stream *stream = file->private_data;
 838         struct lib_ring_buffer *buf = stream->priv;
 839
 840         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 841         module_put(stream->transport->owner);
 842         return lib_ring_buffer_release(inode, file, buf);
 843 }
 844
 845 static
 846 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 847                 struct pipe_inode_info *pipe, size_t len,
 848                 unsigned int flags)
 849 {
 850         struct lttng_metadata_stream *stream = in->private_data;
 851         struct lib_ring_buffer *buf = stream->priv;
 852
 853         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 854                         flags, buf);
 855 }
 856
 857 static
 858 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 859                 struct vm_area_struct *vma)
 860 {
 861         struct lttng_metadata_stream *stream = filp->private_data;
 862         struct lib_ring_buffer *buf = stream->priv;
 863
 864         return lib_ring_buffer_mmap(filp, vma, buf);
 865 }
 866
 867 static
 868 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 869         .owner = THIS_MODULE,
 870         .open = lttng_metadata_ring_buffer_open,
 871         .release = lttng_metadata_ring_buffer_release,
 872         .poll = lttng_metadata_ring_buffer_poll,
 873         .splice_read = lttng_metadata_ring_buffer_splice_read,
 874         .mmap = lttng_metadata_ring_buffer_mmap,
 875         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 876         .llseek = vfs_lib_ring_buffer_no_llseek,
 877 #ifdef CONFIG_COMPAT
 878         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 879 #endif
 880 };
 881
 882 static
 883 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 884                 const struct file_operations *fops)
 885 {
 886         int stream_fd, ret;
 887         struct file *stream_file;
 888
 889         stream_fd = lttng_get_unused_fd();
 890         if (stream_fd < 0) {
 891                 ret = stream_fd;
 892                 goto fd_error;
 893         }
 894         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 895                         stream_priv, O_RDWR);
 896         if (IS_ERR(stream_file)) {
 897                 ret = PTR_ERR(stream_file);
 898                 goto file_error;
 899         }
 900         /*
 901          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 902          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 903          * file descriptor, so we set FMODE_PREAD here.
 904          */
 905         stream_file->f_mode |= FMODE_PREAD;
 906         fd_install(stream_fd, stream_file);
 907         /*
 908          * The stream holds a reference to the channel within the generic ring
 909          * buffer library, so no need to hold a refcount on the channel and
 910          * session files here.
 911          */
 912         return stream_fd;
 913
 914 file_error:
 915         put_unused_fd(stream_fd);
 916 fd_error:
 917         return ret;
 918 }
 919
 920 static
 921 int lttng_abi_open_stream(struct file *channel_file)
 922 {
 923         struct lttng_channel *channel = channel_file->private_data;
 924         struct lib_ring_buffer *buf;
 925         int ret;
 926         void *stream_priv;
 927
 928         buf = channel->ops->buffer_read_open(channel->chan);
 929         if (!buf)
 930                 return -ENOENT;
 931
 932         stream_priv = buf;
 933         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 934                         &lttng_stream_ring_buffer_file_operations);
 935         if (ret < 0)
 936                 goto fd_error;
 937
 938         return ret;
 939
 940 fd_error:
 941         channel->ops->buffer_read_close(buf);
 942         return ret;
 943 }
 944
 945 static
 946 int lttng_abi_open_metadata_stream(struct file *channel_file)
 947 {
 948         struct lttng_channel *channel = channel_file->private_data;
 949         struct lttng_session *session = channel->session;
 950         struct lib_ring_buffer *buf;
 951         int ret;
 952         struct lttng_metadata_stream *metadata_stream;
 953         void *stream_priv;
 954
 955         buf = channel->ops->buffer_read_open(channel->chan);
 956         if (!buf)
 957                 return -ENOENT;
 958
 959         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 960                         GFP_KERNEL);
 961         if (!metadata_stream) {
 962                 ret = -ENOMEM;
 963                 goto nomem;
 964         }
 965         metadata_stream->metadata_cache = session->metadata_cache;
 966         init_waitqueue_head(&metadata_stream->read_wait);
 967         metadata_stream->priv = buf;
 968         stream_priv = metadata_stream;
 969         metadata_stream->transport = channel->transport;
 970
 971         /*
 972          * Since life-time of metadata cache differs from that of
 973          * session, we need to keep our own reference on the transport.
 974          */
 975         if (!try_module_get(metadata_stream->transport->owner)) {
 976                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 977                 ret = -EINVAL;
 978                 goto notransport;
 979         }
 980
 981         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
 982                 ret = -EOVERFLOW;
 983                 goto kref_error;
 984         }
 985
 986         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 987                         &lttng_metadata_ring_buffer_file_operations);
 988         if (ret < 0)
 989                 goto fd_error;
 990
 991         list_add(&metadata_stream->list,
 992                 &session->metadata_cache->metadata_stream);
 993         return ret;
 994
 995 fd_error:
 996         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 997 kref_error:
 998         module_put(metadata_stream->transport->owner);
 999 notransport:
1000         kfree(metadata_stream);
1001 nomem:
1002         channel->ops->buffer_read_close(buf);
1003         return ret;
1004 }
1005
1006 static
1007 int lttng_abi_create_event(struct file *channel_file,
1008                            struct lttng_kernel_event *event_param)
1009 {
1010         struct lttng_channel *channel = channel_file->private_data;
1011         int event_fd, ret;
1012         struct file *event_file;
1013         void *priv;
1014
1015         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1016         switch (event_param->instrumentation) {
1017         case LTTNG_KERNEL_KRETPROBE:
1018                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1019                 break;
1020         case LTTNG_KERNEL_KPROBE:
1021                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1022                 break;
1023         case LTTNG_KERNEL_FUNCTION:
1024                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1025                 break;
1026         default:
1027                 break;
1028         }
1029         event_fd = lttng_get_unused_fd();
1030         if (event_fd < 0) {
1031                 ret = event_fd;
1032                 goto fd_error;
1033         }
1034         event_file = anon_inode_getfile("[lttng_event]",
1035                                         &lttng_event_fops,
1036                                         NULL, O_RDWR);
1037         if (IS_ERR(event_file)) {
1038                 ret = PTR_ERR(event_file);
1039                 goto file_error;
1040         }
1041         /* The event holds a reference on the channel */
1042         if (!atomic_long_add_unless(&channel_file->f_count, 1, LONG_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
1731         ret = lttng_tp_mempool_init();
1732         if (ret) {
1733                 goto error;
1734         }
1735
1736         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1737                                         &lttng_fops, NULL);
1738
1739         if (!lttng_proc_dentry) {
1740                 printk(KERN_ERR "Error creating LTTng control file\n");
1741                 ret = -ENOMEM;
1742                 goto error;
1743         }
1744         lttng_stream_override_ring_buffer_fops();
1745         return 0;
1746
1747 error:
1748         lttng_tp_mempool_destroy();
1749         lttng_clock_unref();
1750         return ret;
1751 }
1752
1753 /* No __exit annotation because used by init error path too. */
1754 void lttng_abi_exit(void)
1755 {
1756         lttng_tp_mempool_destroy();
1757         lttng_clock_unref();
1758         if (lttng_proc_dentry)
1759                 remove_proc_entry("lttng", NULL);
1760 }