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         struct lttng_kernel_channel chan_param;
 495         struct lttng_kernel_old_channel old_chan_param;
 496
 497         switch (cmd) {
 498         case LTTNG_KERNEL_OLD_CHANNEL:
 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                 if (copy_from_user(&chan_param,
 517                                 (struct lttng_kernel_channel __user *) arg,
 518                                 sizeof(struct lttng_kernel_channel)))
 519                         return -EFAULT;
 520                 return lttng_abi_create_channel(file, &chan_param,
 521                                 PER_CPU_CHANNEL);
 522         }
 523         case LTTNG_KERNEL_OLD_SESSION_START:
 524         case LTTNG_KERNEL_OLD_ENABLE:
 525         case LTTNG_KERNEL_SESSION_START:
 526         case LTTNG_KERNEL_ENABLE:
 527                 return lttng_session_enable(session);
 528         case LTTNG_KERNEL_OLD_SESSION_STOP:
 529         case LTTNG_KERNEL_OLD_DISABLE:
 530         case LTTNG_KERNEL_SESSION_STOP:
 531         case LTTNG_KERNEL_DISABLE:
 532                 return lttng_session_disable(session);
 533         case LTTNG_KERNEL_OLD_METADATA:
 534         {
 535                 if (copy_from_user(&old_chan_param,
 536                                 (struct lttng_kernel_old_channel __user *) arg,
 537                                 sizeof(struct lttng_kernel_old_channel)))
 538                         return -EFAULT;
 539                 chan_param.overwrite = old_chan_param.overwrite;
 540                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 541                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 542                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 543                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 544                 chan_param.output = old_chan_param.output;
 545
 546                 return lttng_abi_create_channel(file, &chan_param,
 547                                 METADATA_CHANNEL);
 548         }
 549         case LTTNG_KERNEL_METADATA:
 550         {
 551                 if (copy_from_user(&chan_param,
 552                                         (struct lttng_kernel_channel __user *) arg,
 553                                         sizeof(struct lttng_kernel_channel)))
 554                         return -EFAULT;
 555                 return lttng_abi_create_channel(file, &chan_param,
 556                                 METADATA_CHANNEL);
 557         }
 558         case LTTNG_KERNEL_SESSION_TRACK_PID:
 559                 return lttng_session_track_pid(session, (int) arg);
 560         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 561                 return lttng_session_untrack_pid(session, (int) arg);
 562         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 563                 return lttng_session_list_tracker_pids(session);
 564         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 565                 return lttng_session_metadata_regenerate(session);
 566         case LTTNG_KERNEL_SESSION_STATEDUMP:
 567                 return lttng_session_statedump(session);
 568         default:
 569                 return -ENOIOCTLCMD;
 570         }
 571 }
 572
 573 /*
 574  * Called when the last file reference is dropped.
 575  *
 576  * Big fat note: channels and events are invariant for the whole session after
 577  * their creation. So this session destruction also destroys all channel and
 578  * event structures specific to this session (they are not destroyed when their
 579  * individual file is released).
 580  */
 581 static
 582 int lttng_session_release(struct inode *inode, struct file *file)
 583 {
 584         struct lttng_session *session = file->private_data;
 585
 586         if (session)
 587                 lttng_session_destroy(session);
 588         return 0;
 589 }
 590
 591 static const struct file_operations lttng_session_fops = {
 592         .owner = THIS_MODULE,
 593         .release = lttng_session_release,
 594         .unlocked_ioctl = lttng_session_ioctl,
 595 #ifdef CONFIG_COMPAT
 596         .compat_ioctl = lttng_session_ioctl,
 597 #endif
 598 };
 599
 600 /**
 601  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 602  *      @filp: the file
 603  *      @wait: poll table
 604  *
 605  *      Handles the poll operations for the metadata channels.
 606  */
 607 static
 608 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 609                 poll_table *wait)
 610 {
 611         struct lttng_metadata_stream *stream = filp->private_data;
 612         struct lib_ring_buffer *buf = stream->priv;
 613         int finalized;
 614         unsigned int mask = 0;
 615
 616         if (filp->f_mode & FMODE_READ) {
 617                 poll_wait_set_exclusive(wait);
 618                 poll_wait(filp, &stream->read_wait, wait);
 619
 620                 finalized = stream->finalized;
 621
 622                 /*
 623                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 624                  * ordering finalized load before offsets loads.
 625                  */
 626                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 627
 628                 if (finalized)
 629                         mask |= POLLHUP;
 630
 631                 mutex_lock(&stream->metadata_cache->lock);
 632                 if (stream->metadata_cache->metadata_written >
 633                                 stream->metadata_out)
 634                         mask |= POLLIN;
 635                 mutex_unlock(&stream->metadata_cache->lock);
 636         }
 637
 638         return mask;
 639 }
 640
 641 static
 642 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 643                 unsigned int cmd, unsigned long arg)
 644 {
 645         struct lttng_metadata_stream *stream = filp->private_data;
 646
 647         stream->metadata_out = stream->metadata_in;
 648 }
 649
 650 static
 651 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 652                 unsigned int cmd, unsigned long arg)
 653 {
 654         int ret;
 655         struct lttng_metadata_stream *stream = filp->private_data;
 656         struct lib_ring_buffer *buf = stream->priv;
 657
 658         switch (cmd) {
 659         case RING_BUFFER_GET_NEXT_SUBBUF:
 660         {
 661                 struct lttng_metadata_stream *stream = filp->private_data;
 662                 struct lib_ring_buffer *buf = stream->priv;
 663                 struct channel *chan = buf->backend.chan;
 664
 665                 ret = lttng_metadata_output_channel(stream, chan);
 666                 if (ret > 0) {
 667                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 668                         ret = 0;
 669                 } else if (ret < 0)
 670                         goto err;
 671                 break;
 672         }
 673         case RING_BUFFER_GET_SUBBUF:
 674         {
 675                 /*
 676                  * Random access is not allowed for metadata channel.
 677                  */
 678                 return -ENOSYS;
 679         }
 680         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 681         case RING_BUFFER_FLUSH:
 682         {
 683                 struct lttng_metadata_stream *stream = filp->private_data;
 684                 struct lib_ring_buffer *buf = stream->priv;
 685                 struct channel *chan = buf->backend.chan;
 686
 687                 /*
 688                  * Before doing the actual ring buffer flush, write up to one
 689                  * packet of metadata in the ring buffer.
 690                  */
 691                 ret = lttng_metadata_output_channel(stream, chan);
 692                 if (ret < 0)
 693                         goto err;
 694                 break;
 695         }
 696         case RING_BUFFER_GET_METADATA_VERSION:
 697         {
 698                 struct lttng_metadata_stream *stream = filp->private_data;
 699
 700                 return put_u64(stream->version, arg);
 701         }
 702         default:
 703                 break;
 704         }
 705         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 706
 707         /* Performing lib ring buffer ioctl after our own. */
 708         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 709         if (ret < 0)
 710                 goto err;
 711
 712         switch (cmd) {
 713         case RING_BUFFER_PUT_NEXT_SUBBUF:
 714         {
 715                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 716                                 cmd, arg);
 717                 break;
 718         }
 719         default:
 720                 break;
 721         }
 722 err:
 723         return ret;
 724 }
 725
 726 #ifdef CONFIG_COMPAT
 727 static
 728 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 729                 unsigned int cmd, unsigned long arg)
 730 {
 731         int ret;
 732         struct lttng_metadata_stream *stream = filp->private_data;
 733         struct lib_ring_buffer *buf = stream->priv;
 734
 735         switch (cmd) {
 736         case RING_BUFFER_GET_NEXT_SUBBUF:
 737         {
 738                 struct lttng_metadata_stream *stream = filp->private_data;
 739                 struct lib_ring_buffer *buf = stream->priv;
 740                 struct channel *chan = buf->backend.chan;
 741
 742                 ret = lttng_metadata_output_channel(stream, chan);
 743                 if (ret > 0) {
 744                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 745                         ret = 0;
 746                 } else if (ret < 0)
 747                         goto err;
 748                 break;
 749         }
 750         case RING_BUFFER_GET_SUBBUF:
 751         {
 752                 /*
 753                  * Random access is not allowed for metadata channel.
 754                  */
 755                 return -ENOSYS;
 756         }
 757         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 758         case RING_BUFFER_FLUSH:
 759         {
 760                 struct lttng_metadata_stream *stream = filp->private_data;
 761                 struct lib_ring_buffer *buf = stream->priv;
 762                 struct channel *chan = buf->backend.chan;
 763
 764                 /*
 765                  * Before doing the actual ring buffer flush, write up to one
 766                  * packet of metadata in the ring buffer.
 767                  */
 768                 ret = lttng_metadata_output_channel(stream, chan);
 769                 if (ret < 0)
 770                         goto err;
 771                 break;
 772         }
 773         case RING_BUFFER_GET_METADATA_VERSION:
 774         {
 775                 struct lttng_metadata_stream *stream = filp->private_data;
 776
 777                 return put_u64(stream->version, arg);
 778         }
 779         default:
 780                 break;
 781         }
 782         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 783
 784         /* Performing lib ring buffer ioctl after our own. */
 785         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 786         if (ret < 0)
 787                 goto err;
 788
 789         switch (cmd) {
 790         case RING_BUFFER_PUT_NEXT_SUBBUF:
 791         {
 792                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 793                                 cmd, arg);
 794                 break;
 795         }
 796         default:
 797                 break;
 798         }
 799 err:
 800         return ret;
 801 }
 802 #endif
 803
 804 /*
 805  * This is not used by anonymous file descriptors. This code is left
 806  * there if we ever want to implement an inode with open() operation.
 807  */
 808 static
 809 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 810 {
 811         struct lttng_metadata_stream *stream = inode->i_private;
 812         struct lib_ring_buffer *buf = stream->priv;
 813
 814         file->private_data = buf;
 815         /*
 816          * Since life-time of metadata cache differs from that of
 817          * session, we need to keep our own reference on the transport.
 818          */
 819         if (!try_module_get(stream->transport->owner)) {
 820                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 821                 return -EBUSY;
 822         }
 823         return lib_ring_buffer_open(inode, file, buf);
 824 }
 825
 826 static
 827 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 828 {
 829         struct lttng_metadata_stream *stream = file->private_data;
 830         struct lib_ring_buffer *buf = stream->priv;
 831
 832         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 833         module_put(stream->transport->owner);
 834         return lib_ring_buffer_release(inode, file, buf);
 835 }
 836
 837 static
 838 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 839                 struct pipe_inode_info *pipe, size_t len,
 840                 unsigned int flags)
 841 {
 842         struct lttng_metadata_stream *stream = in->private_data;
 843         struct lib_ring_buffer *buf = stream->priv;
 844
 845         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 846                         flags, buf);
 847 }
 848
 849 static
 850 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 851                 struct vm_area_struct *vma)
 852 {
 853         struct lttng_metadata_stream *stream = filp->private_data;
 854         struct lib_ring_buffer *buf = stream->priv;
 855
 856         return lib_ring_buffer_mmap(filp, vma, buf);
 857 }
 858
 859 static
 860 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 861         .owner = THIS_MODULE,
 862         .open = lttng_metadata_ring_buffer_open,
 863         .release = lttng_metadata_ring_buffer_release,
 864         .poll = lttng_metadata_ring_buffer_poll,
 865         .splice_read = lttng_metadata_ring_buffer_splice_read,
 866         .mmap = lttng_metadata_ring_buffer_mmap,
 867         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 868         .llseek = vfs_lib_ring_buffer_no_llseek,
 869 #ifdef CONFIG_COMPAT
 870         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 871 #endif
 872 };
 873
 874 static
 875 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 876                 const struct file_operations *fops)
 877 {
 878         int stream_fd, ret;
 879         struct file *stream_file;
 880
 881         stream_fd = lttng_get_unused_fd();
 882         if (stream_fd < 0) {
 883                 ret = stream_fd;
 884                 goto fd_error;
 885         }
 886         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 887                         stream_priv, O_RDWR);
 888         if (IS_ERR(stream_file)) {
 889                 ret = PTR_ERR(stream_file);
 890                 goto file_error;
 891         }
 892         /*
 893          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 894          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 895          * file descriptor, so we set FMODE_PREAD here.
 896          */
 897         stream_file->f_mode |= FMODE_PREAD;
 898         fd_install(stream_fd, stream_file);
 899         /*
 900          * The stream holds a reference to the channel within the generic ring
 901          * buffer library, so no need to hold a refcount on the channel and
 902          * session files here.
 903          */
 904         return stream_fd;
 905
 906 file_error:
 907         put_unused_fd(stream_fd);
 908 fd_error:
 909         return ret;
 910 }
 911
 912 static
 913 int lttng_abi_open_stream(struct file *channel_file)
 914 {
 915         struct lttng_channel *channel = channel_file->private_data;
 916         struct lib_ring_buffer *buf;
 917         int ret;
 918         void *stream_priv;
 919
 920         buf = channel->ops->buffer_read_open(channel->chan);
 921         if (!buf)
 922                 return -ENOENT;
 923
 924         stream_priv = buf;
 925         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 926                         &lttng_stream_ring_buffer_file_operations);
 927         if (ret < 0)
 928                 goto fd_error;
 929
 930         return ret;
 931
 932 fd_error:
 933         channel->ops->buffer_read_close(buf);
 934         return ret;
 935 }
 936
 937 static
 938 int lttng_abi_open_metadata_stream(struct file *channel_file)
 939 {
 940         struct lttng_channel *channel = channel_file->private_data;
 941         struct lttng_session *session = channel->session;
 942         struct lib_ring_buffer *buf;
 943         int ret;
 944         struct lttng_metadata_stream *metadata_stream;
 945         void *stream_priv;
 946
 947         buf = channel->ops->buffer_read_open(channel->chan);
 948         if (!buf)
 949                 return -ENOENT;
 950
 951         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 952                         GFP_KERNEL);
 953         if (!metadata_stream) {
 954                 ret = -ENOMEM;
 955                 goto nomem;
 956         }
 957         metadata_stream->metadata_cache = session->metadata_cache;
 958         init_waitqueue_head(&metadata_stream->read_wait);
 959         metadata_stream->priv = buf;
 960         stream_priv = metadata_stream;
 961         metadata_stream->transport = channel->transport;
 962
 963         /*
 964          * Since life-time of metadata cache differs from that of
 965          * session, we need to keep our own reference on the transport.
 966          */
 967         if (!try_module_get(metadata_stream->transport->owner)) {
 968                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 969                 ret = -EINVAL;
 970                 goto notransport;
 971         }
 972
 973         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
 974                 ret = -EOVERFLOW;
 975                 goto kref_error;
 976         }
 977
 978         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 979                         &lttng_metadata_ring_buffer_file_operations);
 980         if (ret < 0)
 981                 goto fd_error;
 982
 983         list_add(&metadata_stream->list,
 984                 &session->metadata_cache->metadata_stream);
 985         return ret;
 986
 987 fd_error:
 988         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 989 kref_error:
 990         module_put(metadata_stream->transport->owner);
 991 notransport:
 992         kfree(metadata_stream);
 993 nomem:
 994         channel->ops->buffer_read_close(buf);
 995         return ret;
 996 }
 997
 998 static
 999 int lttng_abi_create_event(struct file *channel_file,
1000                            struct lttng_kernel_event *event_param)
1001 {
1002         struct lttng_channel *channel = channel_file->private_data;
1003         int event_fd, ret;
1004         struct file *event_file;
1005         void *priv;
1006
1007         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1008         switch (event_param->instrumentation) {
1009         case LTTNG_KERNEL_KRETPROBE:
1010                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1011                 break;
1012         case LTTNG_KERNEL_KPROBE:
1013                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1014                 break;
1015         case LTTNG_KERNEL_FUNCTION:
1016                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1017                 break;
1018         default:
1019                 break;
1020         }
1021         event_fd = lttng_get_unused_fd();
1022         if (event_fd < 0) {
1023                 ret = event_fd;
1024                 goto fd_error;
1025         }
1026         event_file = anon_inode_getfile("[lttng_event]",
1027                                         &lttng_event_fops,
1028                                         NULL, O_RDWR);
1029         if (IS_ERR(event_file)) {
1030                 ret = PTR_ERR(event_file);
1031                 goto file_error;
1032         }
1033         /* The event holds a reference on the channel */
1034         if (!atomic_long_add_unless(&channel_file->f_count, 1, LONG_MAX)) {
1035                 ret = -EOVERFLOW;
1036                 goto refcount_error;
1037         }
1038         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1039                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1040                 struct lttng_enabler *enabler;
1041
1042                 if (strutils_is_star_glob_pattern(event_param->name)) {
1043                         /*
1044                          * If the event name is a star globbing pattern,
1045                          * we create the special star globbing enabler.
1046                          */
1047                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1048                                 event_param, channel);
1049                 } else {
1050                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1051                                 event_param, channel);
1052                 }
1053                 priv = enabler;
1054         } else {
1055                 struct lttng_event *event;
1056
1057                 /*
1058                  * We tolerate no failure path after event creation. It
1059                  * will stay invariant for the rest of the session.
1060                  */
1061                 event = lttng_event_create(channel, event_param,
1062                                 NULL, NULL,
1063                                 event_param->instrumentation);
1064                 WARN_ON_ONCE(!event);
1065                 if (IS_ERR(event)) {
1066                         ret = PTR_ERR(event);
1067                         goto event_error;
1068                 }
1069                 priv = event;
1070         }
1071         event_file->private_data = priv;
1072         fd_install(event_fd, event_file);
1073         return event_fd;
1074
1075 event_error:
1076         atomic_long_dec(&channel_file->f_count);
1077 refcount_error:
1078         fput(event_file);
1079 file_error:
1080         put_unused_fd(event_fd);
1081 fd_error:
1082         return ret;
1083 }
1084
1085 /**
1086  *      lttng_channel_ioctl - lttng syscall through ioctl
1087  *
1088  *      @file: the file
1089  *      @cmd: the command
1090  *      @arg: command arg
1091  *
1092  *      This ioctl implements lttng commands:
1093  *      LTTNG_KERNEL_STREAM
1094  *              Returns an event stream file descriptor or failure.
1095  *              (typically, one event stream records events from one CPU)
1096  *      LTTNG_KERNEL_EVENT
1097  *              Returns an event file descriptor or failure.
1098  *      LTTNG_KERNEL_CONTEXT
1099  *              Prepend a context field to each event in the channel
1100  *      LTTNG_KERNEL_ENABLE
1101  *              Enable recording for events in this channel (weak enable)
1102  *      LTTNG_KERNEL_DISABLE
1103  *              Disable recording for events in this channel (strong disable)
1104  *
1105  * Channel and event file descriptors also hold a reference on the session.
1106  */
1107 static
1108 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1109 {
1110         struct lttng_channel *channel = file->private_data;
1111
1112         switch (cmd) {
1113         case LTTNG_KERNEL_OLD_STREAM:
1114         case LTTNG_KERNEL_STREAM:
1115                 return lttng_abi_open_stream(file);
1116         case LTTNG_KERNEL_OLD_EVENT:
1117         {
1118                 struct lttng_kernel_event *uevent_param;
1119                 struct lttng_kernel_old_event *old_uevent_param;
1120                 int ret;
1121
1122                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1123                                 GFP_KERNEL);
1124                 if (!uevent_param) {
1125                         ret = -ENOMEM;
1126                         goto old_event_end;
1127                 }
1128                 old_uevent_param = kmalloc(
1129                                 sizeof(struct lttng_kernel_old_event),
1130                                 GFP_KERNEL);
1131                 if (!old_uevent_param) {
1132                         ret = -ENOMEM;
1133                         goto old_event_error_free_param;
1134                 }
1135                 if (copy_from_user(old_uevent_param,
1136                                 (struct lttng_kernel_old_event __user *) arg,
1137                                 sizeof(struct lttng_kernel_old_event))) {
1138                         ret = -EFAULT;
1139                         goto old_event_error_free_old_param;
1140                 }
1141
1142                 memcpy(uevent_param->name, old_uevent_param->name,
1143                                 sizeof(uevent_param->name));
1144                 uevent_param->instrumentation =
1145                         old_uevent_param->instrumentation;
1146
1147                 switch (old_uevent_param->instrumentation) {
1148                 case LTTNG_KERNEL_KPROBE:
1149                         uevent_param->u.kprobe.addr =
1150                                 old_uevent_param->u.kprobe.addr;
1151                         uevent_param->u.kprobe.offset =
1152                                 old_uevent_param->u.kprobe.offset;
1153                         memcpy(uevent_param->u.kprobe.symbol_name,
1154                                 old_uevent_param->u.kprobe.symbol_name,
1155                                 sizeof(uevent_param->u.kprobe.symbol_name));
1156                         break;
1157                 case LTTNG_KERNEL_KRETPROBE:
1158                         uevent_param->u.kretprobe.addr =
1159                                 old_uevent_param->u.kretprobe.addr;
1160                         uevent_param->u.kretprobe.offset =
1161                                 old_uevent_param->u.kretprobe.offset;
1162                         memcpy(uevent_param->u.kretprobe.symbol_name,
1163                                 old_uevent_param->u.kretprobe.symbol_name,
1164                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1165                         break;
1166                 case LTTNG_KERNEL_FUNCTION:
1167                         memcpy(uevent_param->u.ftrace.symbol_name,
1168                                         old_uevent_param->u.ftrace.symbol_name,
1169                                         sizeof(uevent_param->u.ftrace.symbol_name));
1170                         break;
1171                 default:
1172                         break;
1173                 }
1174                 ret = lttng_abi_create_event(file, uevent_param);
1175
1176 old_event_error_free_old_param:
1177                 kfree(old_uevent_param);
1178 old_event_error_free_param:
1179                 kfree(uevent_param);
1180 old_event_end:
1181                 return ret;
1182         }
1183         case LTTNG_KERNEL_EVENT:
1184         {
1185                 struct lttng_kernel_event uevent_param;
1186
1187                 if (copy_from_user(&uevent_param,
1188                                 (struct lttng_kernel_event __user *) arg,
1189                                 sizeof(uevent_param)))
1190                         return -EFAULT;
1191                 return lttng_abi_create_event(file, &uevent_param);
1192         }
1193         case LTTNG_KERNEL_OLD_CONTEXT:
1194         {
1195                 struct lttng_kernel_context *ucontext_param;
1196                 struct lttng_kernel_old_context *old_ucontext_param;
1197                 int ret;
1198
1199                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1200                                 GFP_KERNEL);
1201                 if (!ucontext_param) {
1202                         ret = -ENOMEM;
1203                         goto old_ctx_end;
1204                 }
1205                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1206                                 GFP_KERNEL);
1207                 if (!old_ucontext_param) {
1208                         ret = -ENOMEM;
1209                         goto old_ctx_error_free_param;
1210                 }
1211
1212                 if (copy_from_user(old_ucontext_param,
1213                                 (struct lttng_kernel_old_context __user *) arg,
1214                                 sizeof(struct lttng_kernel_old_context))) {
1215                         ret = -EFAULT;
1216                         goto old_ctx_error_free_old_param;
1217                 }
1218                 ucontext_param->ctx = old_ucontext_param->ctx;
1219                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1220                                 sizeof(ucontext_param->padding));
1221                 /* only type that uses the union */
1222                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1223                         ucontext_param->u.perf_counter.type =
1224                                 old_ucontext_param->u.perf_counter.type;
1225                         ucontext_param->u.perf_counter.config =
1226                                 old_ucontext_param->u.perf_counter.config;
1227                         memcpy(ucontext_param->u.perf_counter.name,
1228                                 old_ucontext_param->u.perf_counter.name,
1229                                 sizeof(ucontext_param->u.perf_counter.name));
1230                 }
1231
1232                 ret = lttng_abi_add_context(file,
1233                                 ucontext_param,
1234                                 &channel->ctx, channel->session);
1235
1236 old_ctx_error_free_old_param:
1237                 kfree(old_ucontext_param);
1238 old_ctx_error_free_param:
1239                 kfree(ucontext_param);
1240 old_ctx_end:
1241                 return ret;
1242         }
1243         case LTTNG_KERNEL_CONTEXT:
1244         {
1245                 struct lttng_kernel_context ucontext_param;
1246
1247                 if (copy_from_user(&ucontext_param,
1248                                 (struct lttng_kernel_context __user *) arg,
1249                                 sizeof(ucontext_param)))
1250                         return -EFAULT;
1251                 return lttng_abi_add_context(file,
1252                                 &ucontext_param,
1253                                 &channel->ctx, channel->session);
1254         }
1255         case LTTNG_KERNEL_OLD_ENABLE:
1256         case LTTNG_KERNEL_ENABLE:
1257                 return lttng_channel_enable(channel);
1258         case LTTNG_KERNEL_OLD_DISABLE:
1259         case LTTNG_KERNEL_DISABLE:
1260                 return lttng_channel_disable(channel);
1261         case LTTNG_KERNEL_SYSCALL_MASK:
1262                 return lttng_channel_syscall_mask(channel,
1263                         (struct lttng_kernel_syscall_mask __user *) arg);
1264         default:
1265                 return -ENOIOCTLCMD;
1266         }
1267
1268 }
1269
1270 /**
1271  *      lttng_metadata_ioctl - lttng syscall through ioctl
1272  *
1273  *      @file: the file
1274  *      @cmd: the command
1275  *      @arg: command arg
1276  *
1277  *      This ioctl implements lttng commands:
1278  *      LTTNG_KERNEL_STREAM
1279  *              Returns an event stream file descriptor or failure.
1280  *
1281  * Channel and event file descriptors also hold a reference on the session.
1282  */
1283 static
1284 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1285 {
1286         switch (cmd) {
1287         case LTTNG_KERNEL_OLD_STREAM:
1288         case LTTNG_KERNEL_STREAM:
1289                 return lttng_abi_open_metadata_stream(file);
1290         default:
1291                 return -ENOIOCTLCMD;
1292         }
1293 }
1294
1295 /**
1296  *      lttng_channel_poll - lttng stream addition/removal monitoring
1297  *
1298  *      @file: the file
1299  *      @wait: poll table
1300  */
1301 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1302 {
1303         struct lttng_channel *channel = file->private_data;
1304         unsigned int mask = 0;
1305
1306         if (file->f_mode & FMODE_READ) {
1307                 poll_wait_set_exclusive(wait);
1308                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1309                           wait);
1310
1311                 if (channel->ops->is_disabled(channel->chan))
1312                         return POLLERR;
1313                 if (channel->ops->is_finalized(channel->chan))
1314                         return POLLHUP;
1315                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1316                         return POLLIN | POLLRDNORM;
1317                 return 0;
1318         }
1319         return mask;
1320
1321 }
1322
1323 static
1324 int lttng_channel_release(struct inode *inode, struct file *file)
1325 {
1326         struct lttng_channel *channel = file->private_data;
1327
1328         if (channel)
1329                 fput(channel->session->file);
1330         return 0;
1331 }
1332
1333 static
1334 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1335 {
1336         struct lttng_channel *channel = file->private_data;
1337
1338         if (channel) {
1339                 fput(channel->session->file);
1340                 lttng_metadata_channel_destroy(channel);
1341         }
1342
1343         return 0;
1344 }
1345
1346 static const struct file_operations lttng_channel_fops = {
1347         .owner = THIS_MODULE,
1348         .release = lttng_channel_release,
1349         .poll = lttng_channel_poll,
1350         .unlocked_ioctl = lttng_channel_ioctl,
1351 #ifdef CONFIG_COMPAT
1352         .compat_ioctl = lttng_channel_ioctl,
1353 #endif
1354 };
1355
1356 static const struct file_operations lttng_metadata_fops = {
1357         .owner = THIS_MODULE,
1358         .release = lttng_metadata_channel_release,
1359         .unlocked_ioctl = lttng_metadata_ioctl,
1360 #ifdef CONFIG_COMPAT
1361         .compat_ioctl = lttng_metadata_ioctl,
1362 #endif
1363 };
1364
1365 /**
1366  *      lttng_event_ioctl - lttng syscall through ioctl
1367  *
1368  *      @file: the file
1369  *      @cmd: the command
1370  *      @arg: command arg
1371  *
1372  *      This ioctl implements lttng commands:
1373  *      LTTNG_KERNEL_CONTEXT
1374  *              Prepend a context field to each record of this event
1375  *      LTTNG_KERNEL_ENABLE
1376  *              Enable recording for this event (weak enable)
1377  *      LTTNG_KERNEL_DISABLE
1378  *              Disable recording for this event (strong disable)
1379  */
1380 static
1381 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1382 {
1383         struct lttng_event *event;
1384         struct lttng_enabler *enabler;
1385         enum lttng_event_type *evtype = file->private_data;
1386
1387         switch (cmd) {
1388         case LTTNG_KERNEL_OLD_CONTEXT:
1389         {
1390                 /* Not implemented */
1391                 return -ENOSYS;
1392         }
1393         case LTTNG_KERNEL_CONTEXT:
1394         {
1395                 /* Not implemented */
1396                 return -ENOSYS;
1397         }
1398         case LTTNG_KERNEL_OLD_ENABLE:
1399         case LTTNG_KERNEL_ENABLE:
1400                 switch (*evtype) {
1401                 case LTTNG_TYPE_EVENT:
1402                         event = file->private_data;
1403                         return lttng_event_enable(event);
1404                 case LTTNG_TYPE_ENABLER:
1405                         enabler = file->private_data;
1406                         return lttng_enabler_enable(enabler);
1407                 default:
1408                         WARN_ON_ONCE(1);
1409                         return -ENOSYS;
1410                 }
1411         case LTTNG_KERNEL_OLD_DISABLE:
1412         case LTTNG_KERNEL_DISABLE:
1413                 switch (*evtype) {
1414                 case LTTNG_TYPE_EVENT:
1415                         event = file->private_data;
1416                         return lttng_event_disable(event);
1417                 case LTTNG_TYPE_ENABLER:
1418                         enabler = file->private_data;
1419                         return lttng_enabler_disable(enabler);
1420                 default:
1421                         WARN_ON_ONCE(1);
1422                         return -ENOSYS;
1423                 }
1424         case LTTNG_KERNEL_FILTER:
1425                 switch (*evtype) {
1426                 case LTTNG_TYPE_EVENT:
1427                         return -EINVAL;
1428                 case LTTNG_TYPE_ENABLER:
1429                 {
1430                         enabler = file->private_data;
1431                         return lttng_enabler_attach_bytecode(enabler,
1432                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1433                 }
1434
1435                 }
1436         default:
1437                 return -ENOIOCTLCMD;
1438         }
1439 }
1440
1441 static
1442 int lttng_event_release(struct inode *inode, struct file *file)
1443 {
1444         struct lttng_event *event;
1445         struct lttng_enabler *enabler;
1446         enum lttng_event_type *evtype = file->private_data;
1447
1448         if (!evtype)
1449                 return 0;
1450
1451         switch (*evtype) {
1452         case LTTNG_TYPE_EVENT:
1453                 event = file->private_data;
1454                 if (event)
1455                         fput(event->chan->file);
1456                 break;
1457         case LTTNG_TYPE_ENABLER:
1458                 enabler = file->private_data;
1459                 if (enabler)
1460                         fput(enabler->chan->file);
1461                 break;
1462         default:
1463                 WARN_ON_ONCE(1);
1464                 break;
1465         }
1466
1467         return 0;
1468 }
1469
1470 /* TODO: filter control ioctl */
1471 static const struct file_operations lttng_event_fops = {
1472         .owner = THIS_MODULE,
1473         .release = lttng_event_release,
1474         .unlocked_ioctl = lttng_event_ioctl,
1475 #ifdef CONFIG_COMPAT
1476         .compat_ioctl = lttng_event_ioctl,
1477 #endif
1478 };
1479
1480 static int put_u64(uint64_t val, unsigned long arg)
1481 {
1482         return put_user(val, (uint64_t __user *) arg);
1483 }
1484
1485 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1486                 unsigned int cmd, unsigned long arg)
1487 {
1488         struct lib_ring_buffer *buf = filp->private_data;
1489         struct channel *chan = buf->backend.chan;
1490         const struct lib_ring_buffer_config *config = &chan->backend.config;
1491         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1492         int ret;
1493
1494         if (atomic_read(&chan->record_disabled))
1495                 return -EIO;
1496
1497         switch (cmd) {
1498         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1499         {
1500                 uint64_t ts;
1501
1502                 ret = ops->timestamp_begin(config, buf, &ts);
1503                 if (ret < 0)
1504                         goto error;
1505                 return put_u64(ts, arg);
1506         }
1507         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1508         {
1509                 uint64_t ts;
1510
1511                 ret = ops->timestamp_end(config, buf, &ts);
1512                 if (ret < 0)
1513                         goto error;
1514                 return put_u64(ts, arg);
1515         }
1516         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1517         {
1518                 uint64_t ed;
1519
1520                 ret = ops->events_discarded(config, buf, &ed);
1521                 if (ret < 0)
1522                         goto error;
1523                 return put_u64(ed, arg);
1524         }
1525         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1526         {
1527                 uint64_t cs;
1528
1529                 ret = ops->content_size(config, buf, &cs);
1530                 if (ret < 0)
1531                         goto error;
1532                 return put_u64(cs, arg);
1533         }
1534         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1535         {
1536                 uint64_t ps;
1537
1538                 ret = ops->packet_size(config, buf, &ps);
1539                 if (ret < 0)
1540                         goto error;
1541                 return put_u64(ps, arg);
1542         }
1543         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1544         {
1545                 uint64_t si;
1546
1547                 ret = ops->stream_id(config, buf, &si);
1548                 if (ret < 0)
1549                         goto error;
1550                 return put_u64(si, arg);
1551         }
1552         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1553         {
1554                 uint64_t ts;
1555
1556                 ret = ops->current_timestamp(config, buf, &ts);
1557                 if (ret < 0)
1558                         goto error;
1559                 return put_u64(ts, arg);
1560         }
1561         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1562         {
1563                 uint64_t seq;
1564
1565                 ret = ops->sequence_number(config, buf, &seq);
1566                 if (ret < 0)
1567                         goto error;
1568                 return put_u64(seq, arg);
1569         }
1570         case LTTNG_RING_BUFFER_INSTANCE_ID:
1571         {
1572                 uint64_t id;
1573
1574                 ret = ops->instance_id(config, buf, &id);
1575                 if (ret < 0)
1576                         goto error;
1577                 return put_u64(id, arg);
1578         }
1579         default:
1580                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1581                                 cmd, arg);
1582         }
1583
1584 error:
1585         return -ENOSYS;
1586 }
1587
1588 #ifdef CONFIG_COMPAT
1589 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1590                 unsigned int cmd, unsigned long arg)
1591 {
1592         struct lib_ring_buffer *buf = filp->private_data;
1593         struct channel *chan = buf->backend.chan;
1594         const struct lib_ring_buffer_config *config = &chan->backend.config;
1595         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1596         int ret;
1597
1598         if (atomic_read(&chan->record_disabled))
1599                 return -EIO;
1600
1601         switch (cmd) {
1602         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1603         {
1604                 uint64_t ts;
1605
1606                 ret = ops->timestamp_begin(config, buf, &ts);
1607                 if (ret < 0)
1608                         goto error;
1609                 return put_u64(ts, arg);
1610         }
1611         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1612         {
1613                 uint64_t ts;
1614
1615                 ret = ops->timestamp_end(config, buf, &ts);
1616                 if (ret < 0)
1617                         goto error;
1618                 return put_u64(ts, arg);
1619         }
1620         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1621         {
1622                 uint64_t ed;
1623
1624                 ret = ops->events_discarded(config, buf, &ed);
1625                 if (ret < 0)
1626                         goto error;
1627                 return put_u64(ed, arg);
1628         }
1629         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1630         {
1631                 uint64_t cs;
1632
1633                 ret = ops->content_size(config, buf, &cs);
1634                 if (ret < 0)
1635                         goto error;
1636                 return put_u64(cs, arg);
1637         }
1638         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1639         {
1640                 uint64_t ps;
1641
1642                 ret = ops->packet_size(config, buf, &ps);
1643                 if (ret < 0)
1644                         goto error;
1645                 return put_u64(ps, arg);
1646         }
1647         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1648         {
1649                 uint64_t si;
1650
1651                 ret = ops->stream_id(config, buf, &si);
1652                 if (ret < 0)
1653                         goto error;
1654                 return put_u64(si, arg);
1655         }
1656         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1657         {
1658                 uint64_t ts;
1659
1660                 ret = ops->current_timestamp(config, buf, &ts);
1661                 if (ret < 0)
1662                         goto error;
1663                 return put_u64(ts, arg);
1664         }
1665         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1666         {
1667                 uint64_t seq;
1668
1669                 ret = ops->sequence_number(config, buf, &seq);
1670                 if (ret < 0)
1671                         goto error;
1672                 return put_u64(seq, arg);
1673         }
1674         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1675         {
1676                 uint64_t id;
1677
1678                 ret = ops->instance_id(config, buf, &id);
1679                 if (ret < 0)
1680                         goto error;
1681                 return put_u64(id, arg);
1682         }
1683         default:
1684                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1685                                 cmd, arg);
1686         }
1687
1688 error:
1689         return -ENOSYS;
1690 }
1691 #endif /* CONFIG_COMPAT */
1692
1693 static void lttng_stream_override_ring_buffer_fops(void)
1694 {
1695         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1696         lttng_stream_ring_buffer_file_operations.open =
1697                 lib_ring_buffer_file_operations.open;
1698         lttng_stream_ring_buffer_file_operations.release =
1699                 lib_ring_buffer_file_operations.release;
1700         lttng_stream_ring_buffer_file_operations.poll =
1701                 lib_ring_buffer_file_operations.poll;
1702         lttng_stream_ring_buffer_file_operations.splice_read =
1703                 lib_ring_buffer_file_operations.splice_read;
1704         lttng_stream_ring_buffer_file_operations.mmap =
1705                 lib_ring_buffer_file_operations.mmap;
1706         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1707                 lttng_stream_ring_buffer_ioctl;
1708         lttng_stream_ring_buffer_file_operations.llseek =
1709                 lib_ring_buffer_file_operations.llseek;
1710 #ifdef CONFIG_COMPAT
1711         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1712                 lttng_stream_ring_buffer_compat_ioctl;
1713 #endif
1714 }
1715
1716 int __init lttng_abi_init(void)
1717 {
1718         int ret = 0;
1719
1720         wrapper_vmalloc_sync_all();
1721         lttng_clock_ref();
1722
1723         ret = lttng_tp_mempool_init();
1724         if (ret) {
1725                 goto error;
1726         }
1727
1728         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1729                                         &lttng_fops, NULL);
1730
1731         if (!lttng_proc_dentry) {
1732                 printk(KERN_ERR "Error creating LTTng control file\n");
1733                 ret = -ENOMEM;
1734                 goto error;
1735         }
1736         lttng_stream_override_ring_buffer_fops();
1737         return 0;
1738
1739 error:
1740         lttng_tp_mempool_destroy();
1741         lttng_clock_unref();
1742         return ret;
1743 }
1744
1745 /* No __exit annotation because used by init error path too. */
1746 void lttng_abi_exit(void)
1747 {
1748         lttng_tp_mempool_destroy();
1749         lttng_clock_unref();
1750         if (lttng_proc_dentry)
1751                 remove_proc_entry("lttng", NULL);
1752 }