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,
 434                 1, INT_MAX) == INT_MAX) {
 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 /*
 659  * Reset the counter of how much metadata has been consumed to 0. That way,
 660  * the consumer receives the content of the metadata cache unchanged. This is
 661  * different from the metadata_regenerate where the offset from epoch is
 662  * resampled, here we want the exact same content as the last time the metadata
 663  * was generated. This command is only possible if all the metadata written
 664  * in the cache has been output to the metadata stream to avoid corrupting the
 665  * metadata file.
 666  *
 667  * Return 0 on success, a negative value on error.
 668  */
 669 static
 670 int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
 671 {
 672         int ret;
 673         struct lttng_metadata_cache *cache = stream->metadata_cache;
 674
 675         mutex_lock(&cache->lock);
 676         if (stream->metadata_out != cache->metadata_written) {
 677                 ret = -EBUSY;
 678                 goto end;
 679         }
 680         stream->metadata_out = 0;
 681         stream->metadata_in = 0;
 682         wake_up_interruptible(&stream->read_wait);
 683         ret = 0;
 684
 685 end:
 686         mutex_unlock(&cache->lock);
 687         return ret;
 688 }
 689
 690 static
 691 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 692                 unsigned int cmd, unsigned long arg)
 693 {
 694         int ret;
 695         struct lttng_metadata_stream *stream = filp->private_data;
 696         struct lib_ring_buffer *buf = stream->priv;
 697
 698         switch (cmd) {
 699         case RING_BUFFER_GET_NEXT_SUBBUF:
 700         {
 701                 struct lttng_metadata_stream *stream = filp->private_data;
 702                 struct lib_ring_buffer *buf = stream->priv;
 703                 struct channel *chan = buf->backend.chan;
 704
 705                 ret = lttng_metadata_output_channel(stream, chan);
 706                 if (ret > 0) {
 707                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 708                         ret = 0;
 709                 } else if (ret < 0)
 710                         goto err;
 711                 break;
 712         }
 713         case RING_BUFFER_GET_SUBBUF:
 714         {
 715                 /*
 716                  * Random access is not allowed for metadata channel.
 717                  */
 718                 return -ENOSYS;
 719         }
 720         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 721         case RING_BUFFER_FLUSH:
 722         {
 723                 struct lttng_metadata_stream *stream = filp->private_data;
 724                 struct lib_ring_buffer *buf = stream->priv;
 725                 struct channel *chan = buf->backend.chan;
 726
 727                 /*
 728                  * Before doing the actual ring buffer flush, write up to one
 729                  * packet of metadata in the ring buffer.
 730                  */
 731                 ret = lttng_metadata_output_channel(stream, chan);
 732                 if (ret < 0)
 733                         goto err;
 734                 break;
 735         }
 736         case RING_BUFFER_GET_METADATA_VERSION:
 737         {
 738                 struct lttng_metadata_stream *stream = filp->private_data;
 739
 740                 return put_u64(stream->version, arg);
 741         }
 742         case RING_BUFFER_METADATA_CACHE_DUMP:
 743         {
 744                 struct lttng_metadata_stream *stream = filp->private_data;
 745
 746                 return lttng_metadata_cache_dump(stream);
 747         }
 748         default:
 749                 break;
 750         }
 751         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 752
 753         /* Performing lib ring buffer ioctl after our own. */
 754         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 755         if (ret < 0)
 756                 goto err;
 757
 758         switch (cmd) {
 759         case RING_BUFFER_PUT_NEXT_SUBBUF:
 760         {
 761                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 762                                 cmd, arg);
 763                 break;
 764         }
 765         default:
 766                 break;
 767         }
 768 err:
 769         return ret;
 770 }
 771
 772 #ifdef CONFIG_COMPAT
 773 static
 774 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 775                 unsigned int cmd, unsigned long arg)
 776 {
 777         int ret;
 778         struct lttng_metadata_stream *stream = filp->private_data;
 779         struct lib_ring_buffer *buf = stream->priv;
 780
 781         switch (cmd) {
 782         case RING_BUFFER_GET_NEXT_SUBBUF:
 783         {
 784                 struct lttng_metadata_stream *stream = filp->private_data;
 785                 struct lib_ring_buffer *buf = stream->priv;
 786                 struct channel *chan = buf->backend.chan;
 787
 788                 ret = lttng_metadata_output_channel(stream, chan);
 789                 if (ret > 0) {
 790                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 791                         ret = 0;
 792                 } else if (ret < 0)
 793                         goto err;
 794                 break;
 795         }
 796         case RING_BUFFER_GET_SUBBUF:
 797         {
 798                 /*
 799                  * Random access is not allowed for metadata channel.
 800                  */
 801                 return -ENOSYS;
 802         }
 803         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 804         case RING_BUFFER_FLUSH:
 805         {
 806                 struct lttng_metadata_stream *stream = filp->private_data;
 807                 struct lib_ring_buffer *buf = stream->priv;
 808                 struct channel *chan = buf->backend.chan;
 809
 810                 /*
 811                  * Before doing the actual ring buffer flush, write up to one
 812                  * packet of metadata in the ring buffer.
 813                  */
 814                 ret = lttng_metadata_output_channel(stream, chan);
 815                 if (ret < 0)
 816                         goto err;
 817                 break;
 818         }
 819         case RING_BUFFER_GET_METADATA_VERSION:
 820         {
 821                 struct lttng_metadata_stream *stream = filp->private_data;
 822
 823                 return put_u64(stream->version, arg);
 824         }
 825         case RING_BUFFER_METADATA_CACHE_DUMP:
 826         {
 827                 struct lttng_metadata_stream *stream = filp->private_data;
 828
 829                 return lttng_metadata_cache_dump(stream);
 830         }
 831         default:
 832                 break;
 833         }
 834         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 835
 836         /* Performing lib ring buffer ioctl after our own. */
 837         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 838         if (ret < 0)
 839                 goto err;
 840
 841         switch (cmd) {
 842         case RING_BUFFER_PUT_NEXT_SUBBUF:
 843         {
 844                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 845                                 cmd, arg);
 846                 break;
 847         }
 848         default:
 849                 break;
 850         }
 851 err:
 852         return ret;
 853 }
 854 #endif
 855
 856 /*
 857  * This is not used by anonymous file descriptors. This code is left
 858  * there if we ever want to implement an inode with open() operation.
 859  */
 860 static
 861 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 862 {
 863         struct lttng_metadata_stream *stream = inode->i_private;
 864         struct lib_ring_buffer *buf = stream->priv;
 865
 866         file->private_data = buf;
 867         /*
 868          * Since life-time of metadata cache differs from that of
 869          * session, we need to keep our own reference on the transport.
 870          */
 871         if (!try_module_get(stream->transport->owner)) {
 872                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 873                 return -EBUSY;
 874         }
 875         return lib_ring_buffer_open(inode, file, buf);
 876 }
 877
 878 static
 879 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 880 {
 881         struct lttng_metadata_stream *stream = file->private_data;
 882         struct lib_ring_buffer *buf = stream->priv;
 883
 884         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 885         module_put(stream->transport->owner);
 886         return lib_ring_buffer_release(inode, file, buf);
 887 }
 888
 889 static
 890 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 891                 struct pipe_inode_info *pipe, size_t len,
 892                 unsigned int flags)
 893 {
 894         struct lttng_metadata_stream *stream = in->private_data;
 895         struct lib_ring_buffer *buf = stream->priv;
 896
 897         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 898                         flags, buf);
 899 }
 900
 901 static
 902 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 903                 struct vm_area_struct *vma)
 904 {
 905         struct lttng_metadata_stream *stream = filp->private_data;
 906         struct lib_ring_buffer *buf = stream->priv;
 907
 908         return lib_ring_buffer_mmap(filp, vma, buf);
 909 }
 910
 911 static
 912 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 913         .owner = THIS_MODULE,
 914         .open = lttng_metadata_ring_buffer_open,
 915         .release = lttng_metadata_ring_buffer_release,
 916         .poll = lttng_metadata_ring_buffer_poll,
 917         .splice_read = lttng_metadata_ring_buffer_splice_read,
 918         .mmap = lttng_metadata_ring_buffer_mmap,
 919         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 920         .llseek = vfs_lib_ring_buffer_no_llseek,
 921 #ifdef CONFIG_COMPAT
 922         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 923 #endif
 924 };
 925
 926 static
 927 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 928                 const struct file_operations *fops)
 929 {
 930         int stream_fd, ret;
 931         struct file *stream_file;
 932
 933         stream_fd = lttng_get_unused_fd();
 934         if (stream_fd < 0) {
 935                 ret = stream_fd;
 936                 goto fd_error;
 937         }
 938         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 939                         stream_priv, O_RDWR);
 940         if (IS_ERR(stream_file)) {
 941                 ret = PTR_ERR(stream_file);
 942                 goto file_error;
 943         }
 944         /*
 945          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 946          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 947          * file descriptor, so we set FMODE_PREAD here.
 948          */
 949         stream_file->f_mode |= FMODE_PREAD;
 950         fd_install(stream_fd, stream_file);
 951         /*
 952          * The stream holds a reference to the channel within the generic ring
 953          * buffer library, so no need to hold a refcount on the channel and
 954          * session files here.
 955          */
 956         return stream_fd;
 957
 958 file_error:
 959         put_unused_fd(stream_fd);
 960 fd_error:
 961         return ret;
 962 }
 963
 964 static
 965 int lttng_abi_open_stream(struct file *channel_file)
 966 {
 967         struct lttng_channel *channel = channel_file->private_data;
 968         struct lib_ring_buffer *buf;
 969         int ret;
 970         void *stream_priv;
 971
 972         buf = channel->ops->buffer_read_open(channel->chan);
 973         if (!buf)
 974                 return -ENOENT;
 975
 976         stream_priv = buf;
 977         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 978                         &lttng_stream_ring_buffer_file_operations);
 979         if (ret < 0)
 980                 goto fd_error;
 981
 982         return ret;
 983
 984 fd_error:
 985         channel->ops->buffer_read_close(buf);
 986         return ret;
 987 }
 988
 989 static
 990 int lttng_abi_open_metadata_stream(struct file *channel_file)
 991 {
 992         struct lttng_channel *channel = channel_file->private_data;
 993         struct lttng_session *session = channel->session;
 994         struct lib_ring_buffer *buf;
 995         int ret;
 996         struct lttng_metadata_stream *metadata_stream;
 997         void *stream_priv;
 998
 999         buf = channel->ops->buffer_read_open(channel->chan);
1000         if (!buf)
1001                 return -ENOENT;
1002
1003         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
1004                         GFP_KERNEL);
1005         if (!metadata_stream) {
1006                 ret = -ENOMEM;
1007                 goto nomem;
1008         }
1009         metadata_stream->metadata_cache = session->metadata_cache;
1010         init_waitqueue_head(&metadata_stream->read_wait);
1011         metadata_stream->priv = buf;
1012         stream_priv = metadata_stream;
1013         metadata_stream->transport = channel->transport;
1014
1015         /*
1016          * Since life-time of metadata cache differs from that of
1017          * session, we need to keep our own reference on the transport.
1018          */
1019         if (!try_module_get(metadata_stream->transport->owner)) {
1020                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
1021                 ret = -EINVAL;
1022                 goto notransport;
1023         }
1024
1025         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1026                 ret = -EOVERFLOW;
1027                 goto kref_error;
1028         }
1029
1030         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1031                         &lttng_metadata_ring_buffer_file_operations);
1032         if (ret < 0)
1033                 goto fd_error;
1034
1035         list_add(&metadata_stream->list,
1036                 &session->metadata_cache->metadata_stream);
1037         return ret;
1038
1039 fd_error:
1040         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1041 kref_error:
1042         module_put(metadata_stream->transport->owner);
1043 notransport:
1044         kfree(metadata_stream);
1045 nomem:
1046         channel->ops->buffer_read_close(buf);
1047         return ret;
1048 }
1049
1050 static
1051 int lttng_abi_create_event(struct file *channel_file,
1052                            struct lttng_kernel_event *event_param)
1053 {
1054         struct lttng_channel *channel = channel_file->private_data;
1055         int event_fd, ret;
1056         struct file *event_file;
1057         void *priv;
1058
1059         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1060         switch (event_param->instrumentation) {
1061         case LTTNG_KERNEL_KRETPROBE:
1062                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1063                 break;
1064         case LTTNG_KERNEL_KPROBE:
1065                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1066                 break;
1067         case LTTNG_KERNEL_FUNCTION:
1068                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1069                 break;
1070         default:
1071                 break;
1072         }
1073         event_fd = lttng_get_unused_fd();
1074         if (event_fd < 0) {
1075                 ret = event_fd;
1076                 goto fd_error;
1077         }
1078         event_file = anon_inode_getfile("[lttng_event]",
1079                                         &lttng_event_fops,
1080                                         NULL, O_RDWR);
1081         if (IS_ERR(event_file)) {
1082                 ret = PTR_ERR(event_file);
1083                 goto file_error;
1084         }
1085         /* The event holds a reference on the channel */
1086         if (atomic_long_add_unless(&channel_file->f_count,
1087                 1, INT_MAX) == INT_MAX) {
1088                 ret = -EOVERFLOW;
1089                 goto refcount_error;
1090         }
1091         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1092                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1093                 struct lttng_enabler *enabler;
1094
1095                 if (strutils_is_star_glob_pattern(event_param->name)) {
1096                         /*
1097                          * If the event name is a star globbing pattern,
1098                          * we create the special star globbing enabler.
1099                          */
1100                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1101                                 event_param, channel);
1102                 } else {
1103                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1104                                 event_param, channel);
1105                 }
1106                 priv = enabler;
1107         } else {
1108                 struct lttng_event *event;
1109
1110                 /*
1111                  * We tolerate no failure path after event creation. It
1112                  * will stay invariant for the rest of the session.
1113                  */
1114                 event = lttng_event_create(channel, event_param,
1115                                 NULL, NULL,
1116                                 event_param->instrumentation);
1117                 WARN_ON_ONCE(!event);
1118                 if (IS_ERR(event)) {
1119                         ret = PTR_ERR(event);
1120                         goto event_error;
1121                 }
1122                 priv = event;
1123         }
1124         event_file->private_data = priv;
1125         fd_install(event_fd, event_file);
1126         return event_fd;
1127
1128 event_error:
1129         atomic_long_dec(&channel_file->f_count);
1130 refcount_error:
1131         fput(event_file);
1132 file_error:
1133         put_unused_fd(event_fd);
1134 fd_error:
1135         return ret;
1136 }
1137
1138 /**
1139  *      lttng_channel_ioctl - lttng syscall through ioctl
1140  *
1141  *      @file: the file
1142  *      @cmd: the command
1143  *      @arg: command arg
1144  *
1145  *      This ioctl implements lttng commands:
1146  *      LTTNG_KERNEL_STREAM
1147  *              Returns an event stream file descriptor or failure.
1148  *              (typically, one event stream records events from one CPU)
1149  *      LTTNG_KERNEL_EVENT
1150  *              Returns an event file descriptor or failure.
1151  *      LTTNG_KERNEL_CONTEXT
1152  *              Prepend a context field to each event in the channel
1153  *      LTTNG_KERNEL_ENABLE
1154  *              Enable recording for events in this channel (weak enable)
1155  *      LTTNG_KERNEL_DISABLE
1156  *              Disable recording for events in this channel (strong disable)
1157  *
1158  * Channel and event file descriptors also hold a reference on the session.
1159  */
1160 static
1161 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1162 {
1163         struct lttng_channel *channel = file->private_data;
1164
1165         switch (cmd) {
1166         case LTTNG_KERNEL_OLD_STREAM:
1167         case LTTNG_KERNEL_STREAM:
1168                 return lttng_abi_open_stream(file);
1169         case LTTNG_KERNEL_OLD_EVENT:
1170         {
1171                 struct lttng_kernel_event *uevent_param;
1172                 struct lttng_kernel_old_event *old_uevent_param;
1173                 int ret;
1174
1175                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1176                                 GFP_KERNEL);
1177                 if (!uevent_param) {
1178                         ret = -ENOMEM;
1179                         goto old_event_end;
1180                 }
1181                 old_uevent_param = kmalloc(
1182                                 sizeof(struct lttng_kernel_old_event),
1183                                 GFP_KERNEL);
1184                 if (!old_uevent_param) {
1185                         ret = -ENOMEM;
1186                         goto old_event_error_free_param;
1187                 }
1188                 if (copy_from_user(old_uevent_param,
1189                                 (struct lttng_kernel_old_event __user *) arg,
1190                                 sizeof(struct lttng_kernel_old_event))) {
1191                         ret = -EFAULT;
1192                         goto old_event_error_free_old_param;
1193                 }
1194
1195                 memcpy(uevent_param->name, old_uevent_param->name,
1196                                 sizeof(uevent_param->name));
1197                 uevent_param->instrumentation =
1198                         old_uevent_param->instrumentation;
1199
1200                 switch (old_uevent_param->instrumentation) {
1201                 case LTTNG_KERNEL_KPROBE:
1202                         uevent_param->u.kprobe.addr =
1203                                 old_uevent_param->u.kprobe.addr;
1204                         uevent_param->u.kprobe.offset =
1205                                 old_uevent_param->u.kprobe.offset;
1206                         memcpy(uevent_param->u.kprobe.symbol_name,
1207                                 old_uevent_param->u.kprobe.symbol_name,
1208                                 sizeof(uevent_param->u.kprobe.symbol_name));
1209                         break;
1210                 case LTTNG_KERNEL_KRETPROBE:
1211                         uevent_param->u.kretprobe.addr =
1212                                 old_uevent_param->u.kretprobe.addr;
1213                         uevent_param->u.kretprobe.offset =
1214                                 old_uevent_param->u.kretprobe.offset;
1215                         memcpy(uevent_param->u.kretprobe.symbol_name,
1216                                 old_uevent_param->u.kretprobe.symbol_name,
1217                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1218                         break;
1219                 case LTTNG_KERNEL_FUNCTION:
1220                         memcpy(uevent_param->u.ftrace.symbol_name,
1221                                         old_uevent_param->u.ftrace.symbol_name,
1222                                         sizeof(uevent_param->u.ftrace.symbol_name));
1223                         break;
1224                 default:
1225                         break;
1226                 }
1227                 ret = lttng_abi_create_event(file, uevent_param);
1228
1229 old_event_error_free_old_param:
1230                 kfree(old_uevent_param);
1231 old_event_error_free_param:
1232                 kfree(uevent_param);
1233 old_event_end:
1234                 return ret;
1235         }
1236         case LTTNG_KERNEL_EVENT:
1237         {
1238                 struct lttng_kernel_event uevent_param;
1239
1240                 if (copy_from_user(&uevent_param,
1241                                 (struct lttng_kernel_event __user *) arg,
1242                                 sizeof(uevent_param)))
1243                         return -EFAULT;
1244                 return lttng_abi_create_event(file, &uevent_param);
1245         }
1246         case LTTNG_KERNEL_OLD_CONTEXT:
1247         {
1248                 struct lttng_kernel_context *ucontext_param;
1249                 struct lttng_kernel_old_context *old_ucontext_param;
1250                 int ret;
1251
1252                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1253                                 GFP_KERNEL);
1254                 if (!ucontext_param) {
1255                         ret = -ENOMEM;
1256                         goto old_ctx_end;
1257                 }
1258                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1259                                 GFP_KERNEL);
1260                 if (!old_ucontext_param) {
1261                         ret = -ENOMEM;
1262                         goto old_ctx_error_free_param;
1263                 }
1264
1265                 if (copy_from_user(old_ucontext_param,
1266                                 (struct lttng_kernel_old_context __user *) arg,
1267                                 sizeof(struct lttng_kernel_old_context))) {
1268                         ret = -EFAULT;
1269                         goto old_ctx_error_free_old_param;
1270                 }
1271                 ucontext_param->ctx = old_ucontext_param->ctx;
1272                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1273                                 sizeof(ucontext_param->padding));
1274                 /* only type that uses the union */
1275                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1276                         ucontext_param->u.perf_counter.type =
1277                                 old_ucontext_param->u.perf_counter.type;
1278                         ucontext_param->u.perf_counter.config =
1279                                 old_ucontext_param->u.perf_counter.config;
1280                         memcpy(ucontext_param->u.perf_counter.name,
1281                                 old_ucontext_param->u.perf_counter.name,
1282                                 sizeof(ucontext_param->u.perf_counter.name));
1283                 }
1284
1285                 ret = lttng_abi_add_context(file,
1286                                 ucontext_param,
1287                                 &channel->ctx, channel->session);
1288
1289 old_ctx_error_free_old_param:
1290                 kfree(old_ucontext_param);
1291 old_ctx_error_free_param:
1292                 kfree(ucontext_param);
1293 old_ctx_end:
1294                 return ret;
1295         }
1296         case LTTNG_KERNEL_CONTEXT:
1297         {
1298                 struct lttng_kernel_context ucontext_param;
1299
1300                 if (copy_from_user(&ucontext_param,
1301                                 (struct lttng_kernel_context __user *) arg,
1302                                 sizeof(ucontext_param)))
1303                         return -EFAULT;
1304                 return lttng_abi_add_context(file,
1305                                 &ucontext_param,
1306                                 &channel->ctx, channel->session);
1307         }
1308         case LTTNG_KERNEL_OLD_ENABLE:
1309         case LTTNG_KERNEL_ENABLE:
1310                 return lttng_channel_enable(channel);
1311         case LTTNG_KERNEL_OLD_DISABLE:
1312         case LTTNG_KERNEL_DISABLE:
1313                 return lttng_channel_disable(channel);
1314         case LTTNG_KERNEL_SYSCALL_MASK:
1315                 return lttng_channel_syscall_mask(channel,
1316                         (struct lttng_kernel_syscall_mask __user *) arg);
1317         default:
1318                 return -ENOIOCTLCMD;
1319         }
1320
1321 }
1322
1323 /**
1324  *      lttng_metadata_ioctl - lttng syscall through ioctl
1325  *
1326  *      @file: the file
1327  *      @cmd: the command
1328  *      @arg: command arg
1329  *
1330  *      This ioctl implements lttng commands:
1331  *      LTTNG_KERNEL_STREAM
1332  *              Returns an event stream file descriptor or failure.
1333  *
1334  * Channel and event file descriptors also hold a reference on the session.
1335  */
1336 static
1337 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1338 {
1339         switch (cmd) {
1340         case LTTNG_KERNEL_OLD_STREAM:
1341         case LTTNG_KERNEL_STREAM:
1342                 return lttng_abi_open_metadata_stream(file);
1343         default:
1344                 return -ENOIOCTLCMD;
1345         }
1346 }
1347
1348 /**
1349  *      lttng_channel_poll - lttng stream addition/removal monitoring
1350  *
1351  *      @file: the file
1352  *      @wait: poll table
1353  */
1354 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1355 {
1356         struct lttng_channel *channel = file->private_data;
1357         unsigned int mask = 0;
1358
1359         if (file->f_mode & FMODE_READ) {
1360                 poll_wait_set_exclusive(wait);
1361                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1362                           wait);
1363
1364                 if (channel->ops->is_disabled(channel->chan))
1365                         return POLLERR;
1366                 if (channel->ops->is_finalized(channel->chan))
1367                         return POLLHUP;
1368                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1369                         return POLLIN | POLLRDNORM;
1370                 return 0;
1371         }
1372         return mask;
1373
1374 }
1375
1376 static
1377 int lttng_channel_release(struct inode *inode, struct file *file)
1378 {
1379         struct lttng_channel *channel = file->private_data;
1380
1381         if (channel)
1382                 fput(channel->session->file);
1383         return 0;
1384 }
1385
1386 static
1387 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1388 {
1389         struct lttng_channel *channel = file->private_data;
1390
1391         if (channel) {
1392                 fput(channel->session->file);
1393                 lttng_metadata_channel_destroy(channel);
1394         }
1395
1396         return 0;
1397 }
1398
1399 static const struct file_operations lttng_channel_fops = {
1400         .owner = THIS_MODULE,
1401         .release = lttng_channel_release,
1402         .poll = lttng_channel_poll,
1403         .unlocked_ioctl = lttng_channel_ioctl,
1404 #ifdef CONFIG_COMPAT
1405         .compat_ioctl = lttng_channel_ioctl,
1406 #endif
1407 };
1408
1409 static const struct file_operations lttng_metadata_fops = {
1410         .owner = THIS_MODULE,
1411         .release = lttng_metadata_channel_release,
1412         .unlocked_ioctl = lttng_metadata_ioctl,
1413 #ifdef CONFIG_COMPAT
1414         .compat_ioctl = lttng_metadata_ioctl,
1415 #endif
1416 };
1417
1418 /**
1419  *      lttng_event_ioctl - lttng syscall through ioctl
1420  *
1421  *      @file: the file
1422  *      @cmd: the command
1423  *      @arg: command arg
1424  *
1425  *      This ioctl implements lttng commands:
1426  *      LTTNG_KERNEL_CONTEXT
1427  *              Prepend a context field to each record of this event
1428  *      LTTNG_KERNEL_ENABLE
1429  *              Enable recording for this event (weak enable)
1430  *      LTTNG_KERNEL_DISABLE
1431  *              Disable recording for this event (strong disable)
1432  */
1433 static
1434 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1435 {
1436         struct lttng_event *event;
1437         struct lttng_enabler *enabler;
1438         enum lttng_event_type *evtype = file->private_data;
1439
1440         switch (cmd) {
1441         case LTTNG_KERNEL_OLD_CONTEXT:
1442         {
1443                 /* Not implemented */
1444                 return -ENOSYS;
1445         }
1446         case LTTNG_KERNEL_CONTEXT:
1447         {
1448                 /* Not implemented */
1449                 return -ENOSYS;
1450         }
1451         case LTTNG_KERNEL_OLD_ENABLE:
1452         case LTTNG_KERNEL_ENABLE:
1453                 switch (*evtype) {
1454                 case LTTNG_TYPE_EVENT:
1455                         event = file->private_data;
1456                         return lttng_event_enable(event);
1457                 case LTTNG_TYPE_ENABLER:
1458                         enabler = file->private_data;
1459                         return lttng_enabler_enable(enabler);
1460                 default:
1461                         WARN_ON_ONCE(1);
1462                         return -ENOSYS;
1463                 }
1464         case LTTNG_KERNEL_OLD_DISABLE:
1465         case LTTNG_KERNEL_DISABLE:
1466                 switch (*evtype) {
1467                 case LTTNG_TYPE_EVENT:
1468                         event = file->private_data;
1469                         return lttng_event_disable(event);
1470                 case LTTNG_TYPE_ENABLER:
1471                         enabler = file->private_data;
1472                         return lttng_enabler_disable(enabler);
1473                 default:
1474                         WARN_ON_ONCE(1);
1475                         return -ENOSYS;
1476                 }
1477         case LTTNG_KERNEL_FILTER:
1478                 switch (*evtype) {
1479                 case LTTNG_TYPE_EVENT:
1480                         return -EINVAL;
1481                 case LTTNG_TYPE_ENABLER:
1482                 {
1483                         enabler = file->private_data;
1484                         return lttng_enabler_attach_bytecode(enabler,
1485                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1486                 }
1487
1488                 }
1489         default:
1490                 return -ENOIOCTLCMD;
1491         }
1492 }
1493
1494 static
1495 int lttng_event_release(struct inode *inode, struct file *file)
1496 {
1497         struct lttng_event *event;
1498         struct lttng_enabler *enabler;
1499         enum lttng_event_type *evtype = file->private_data;
1500
1501         if (!evtype)
1502                 return 0;
1503
1504         switch (*evtype) {
1505         case LTTNG_TYPE_EVENT:
1506                 event = file->private_data;
1507                 if (event)
1508                         fput(event->chan->file);
1509                 break;
1510         case LTTNG_TYPE_ENABLER:
1511                 enabler = file->private_data;
1512                 if (enabler)
1513                         fput(enabler->chan->file);
1514                 break;
1515         default:
1516                 WARN_ON_ONCE(1);
1517                 break;
1518         }
1519
1520         return 0;
1521 }
1522
1523 /* TODO: filter control ioctl */
1524 static const struct file_operations lttng_event_fops = {
1525         .owner = THIS_MODULE,
1526         .release = lttng_event_release,
1527         .unlocked_ioctl = lttng_event_ioctl,
1528 #ifdef CONFIG_COMPAT
1529         .compat_ioctl = lttng_event_ioctl,
1530 #endif
1531 };
1532
1533 static int put_u64(uint64_t val, unsigned long arg)
1534 {
1535         return put_user(val, (uint64_t __user *) arg);
1536 }
1537
1538 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1539                 unsigned int cmd, unsigned long arg)
1540 {
1541         struct lib_ring_buffer *buf = filp->private_data;
1542         struct channel *chan = buf->backend.chan;
1543         const struct lib_ring_buffer_config *config = &chan->backend.config;
1544         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1545         int ret;
1546
1547         if (atomic_read(&chan->record_disabled))
1548                 return -EIO;
1549
1550         switch (cmd) {
1551         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1552         {
1553                 uint64_t ts;
1554
1555                 ret = ops->timestamp_begin(config, buf, &ts);
1556                 if (ret < 0)
1557                         goto error;
1558                 return put_u64(ts, arg);
1559         }
1560         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1561         {
1562                 uint64_t ts;
1563
1564                 ret = ops->timestamp_end(config, buf, &ts);
1565                 if (ret < 0)
1566                         goto error;
1567                 return put_u64(ts, arg);
1568         }
1569         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1570         {
1571                 uint64_t ed;
1572
1573                 ret = ops->events_discarded(config, buf, &ed);
1574                 if (ret < 0)
1575                         goto error;
1576                 return put_u64(ed, arg);
1577         }
1578         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1579         {
1580                 uint64_t cs;
1581
1582                 ret = ops->content_size(config, buf, &cs);
1583                 if (ret < 0)
1584                         goto error;
1585                 return put_u64(cs, arg);
1586         }
1587         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1588         {
1589                 uint64_t ps;
1590
1591                 ret = ops->packet_size(config, buf, &ps);
1592                 if (ret < 0)
1593                         goto error;
1594                 return put_u64(ps, arg);
1595         }
1596         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1597         {
1598                 uint64_t si;
1599
1600                 ret = ops->stream_id(config, buf, &si);
1601                 if (ret < 0)
1602                         goto error;
1603                 return put_u64(si, arg);
1604         }
1605         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1606         {
1607                 uint64_t ts;
1608
1609                 ret = ops->current_timestamp(config, buf, &ts);
1610                 if (ret < 0)
1611                         goto error;
1612                 return put_u64(ts, arg);
1613         }
1614         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1615         {
1616                 uint64_t seq;
1617
1618                 ret = ops->sequence_number(config, buf, &seq);
1619                 if (ret < 0)
1620                         goto error;
1621                 return put_u64(seq, arg);
1622         }
1623         case LTTNG_RING_BUFFER_INSTANCE_ID:
1624         {
1625                 uint64_t id;
1626
1627                 ret = ops->instance_id(config, buf, &id);
1628                 if (ret < 0)
1629                         goto error;
1630                 return put_u64(id, arg);
1631         }
1632         default:
1633                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1634                                 cmd, arg);
1635         }
1636
1637 error:
1638         return -ENOSYS;
1639 }
1640
1641 #ifdef CONFIG_COMPAT
1642 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1643                 unsigned int cmd, unsigned long arg)
1644 {
1645         struct lib_ring_buffer *buf = filp->private_data;
1646         struct channel *chan = buf->backend.chan;
1647         const struct lib_ring_buffer_config *config = &chan->backend.config;
1648         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1649         int ret;
1650
1651         if (atomic_read(&chan->record_disabled))
1652                 return -EIO;
1653
1654         switch (cmd) {
1655         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1656         {
1657                 uint64_t ts;
1658
1659                 ret = ops->timestamp_begin(config, buf, &ts);
1660                 if (ret < 0)
1661                         goto error;
1662                 return put_u64(ts, arg);
1663         }
1664         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1665         {
1666                 uint64_t ts;
1667
1668                 ret = ops->timestamp_end(config, buf, &ts);
1669                 if (ret < 0)
1670                         goto error;
1671                 return put_u64(ts, arg);
1672         }
1673         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1674         {
1675                 uint64_t ed;
1676
1677                 ret = ops->events_discarded(config, buf, &ed);
1678                 if (ret < 0)
1679                         goto error;
1680                 return put_u64(ed, arg);
1681         }
1682         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1683         {
1684                 uint64_t cs;
1685
1686                 ret = ops->content_size(config, buf, &cs);
1687                 if (ret < 0)
1688                         goto error;
1689                 return put_u64(cs, arg);
1690         }
1691         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1692         {
1693                 uint64_t ps;
1694
1695                 ret = ops->packet_size(config, buf, &ps);
1696                 if (ret < 0)
1697                         goto error;
1698                 return put_u64(ps, arg);
1699         }
1700         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1701         {
1702                 uint64_t si;
1703
1704                 ret = ops->stream_id(config, buf, &si);
1705                 if (ret < 0)
1706                         goto error;
1707                 return put_u64(si, arg);
1708         }
1709         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1710         {
1711                 uint64_t ts;
1712
1713                 ret = ops->current_timestamp(config, buf, &ts);
1714                 if (ret < 0)
1715                         goto error;
1716                 return put_u64(ts, arg);
1717         }
1718         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1719         {
1720                 uint64_t seq;
1721
1722                 ret = ops->sequence_number(config, buf, &seq);
1723                 if (ret < 0)
1724                         goto error;
1725                 return put_u64(seq, arg);
1726         }
1727         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1728         {
1729                 uint64_t id;
1730
1731                 ret = ops->instance_id(config, buf, &id);
1732                 if (ret < 0)
1733                         goto error;
1734                 return put_u64(id, arg);
1735         }
1736         default:
1737                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1738                                 cmd, arg);
1739         }
1740
1741 error:
1742         return -ENOSYS;
1743 }
1744 #endif /* CONFIG_COMPAT */
1745
1746 static void lttng_stream_override_ring_buffer_fops(void)
1747 {
1748         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1749         lttng_stream_ring_buffer_file_operations.open =
1750                 lib_ring_buffer_file_operations.open;
1751         lttng_stream_ring_buffer_file_operations.release =
1752                 lib_ring_buffer_file_operations.release;
1753         lttng_stream_ring_buffer_file_operations.poll =
1754                 lib_ring_buffer_file_operations.poll;
1755         lttng_stream_ring_buffer_file_operations.splice_read =
1756                 lib_ring_buffer_file_operations.splice_read;
1757         lttng_stream_ring_buffer_file_operations.mmap =
1758                 lib_ring_buffer_file_operations.mmap;
1759         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1760                 lttng_stream_ring_buffer_ioctl;
1761         lttng_stream_ring_buffer_file_operations.llseek =
1762                 lib_ring_buffer_file_operations.llseek;
1763 #ifdef CONFIG_COMPAT
1764         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1765                 lttng_stream_ring_buffer_compat_ioctl;
1766 #endif
1767 }
1768
1769 int __init lttng_abi_init(void)
1770 {
1771         int ret = 0;
1772
1773         wrapper_vmalloc_sync_all();
1774         lttng_clock_ref();
1775
1776         ret = lttng_tp_mempool_init();
1777         if (ret) {
1778                 goto error;
1779         }
1780
1781         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1782                                         &lttng_fops, NULL);
1783
1784         if (!lttng_proc_dentry) {
1785                 printk(KERN_ERR "Error creating LTTng control file\n");
1786                 ret = -ENOMEM;
1787                 goto error;
1788         }
1789         lttng_stream_override_ring_buffer_fops();
1790         return 0;
1791
1792 error:
1793         lttng_tp_mempool_destroy();
1794         lttng_clock_unref();
1795         return ret;
1796 }
1797
1798 /* No __exit annotation because used by init error path too. */
1799 void lttng_abi_exit(void)
1800 {
1801         lttng_tp_mempool_destroy();
1802         lttng_clock_unref();
1803         if (lttng_proc_dentry)
1804                 remove_proc_entry("lttng", NULL);
1805 }