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-abi.h>
  55 #include <lttng-abi-old.h>
  56 #include <lttng-events.h>
  57 #include <lttng-tracer.h>
  58 #include <lib/ringbuffer/frontend_types.h>
  59
  60 /*
  61  * This is LTTng's own personal way to create a system call as an external
  62  * module. We use ioctl() on /proc/lttng.
  63  */
  64
  65 static struct proc_dir_entry *lttng_proc_dentry;
  66 static const struct file_operations lttng_fops;
  67 static const struct file_operations lttng_session_fops;
  68 static const struct file_operations lttng_channel_fops;
  69 static const struct file_operations lttng_metadata_fops;
  70 static const struct file_operations lttng_event_fops;
  71 static struct file_operations lttng_stream_ring_buffer_file_operations;
  72
  73 static int put_u64(uint64_t val, unsigned long arg);
  74
  75 /*
  76  * Teardown management: opened file descriptors keep a refcount on the module,
  77  * so it can only exit when all file descriptors are closed.
  78  */
  79
  80 static
  81 int lttng_abi_create_session(void)
  82 {
  83         struct lttng_session *session;
  84         struct file *session_file;
  85         int session_fd, ret;
  86
  87         session = lttng_session_create();
  88         if (!session)
  89                 return -ENOMEM;
  90         session_fd = lttng_get_unused_fd();
  91         if (session_fd < 0) {
  92                 ret = session_fd;
  93                 goto fd_error;
  94         }
  95         session_file = anon_inode_getfile("[lttng_session]",
  96                                           &lttng_session_fops,
  97                                           session, O_RDWR);
  98         if (IS_ERR(session_file)) {
  99                 ret = PTR_ERR(session_file);
 100                 goto file_error;
 101         }
 102         session->file = session_file;
 103         fd_install(session_fd, session_file);
 104         return session_fd;
 105
 106 file_error:
 107         put_unused_fd(session_fd);
 108 fd_error:
 109         lttng_session_destroy(session);
 110         return ret;
 111 }
 112
 113 static
 114 int lttng_abi_tracepoint_list(void)
 115 {
 116         struct file *tracepoint_list_file;
 117         int file_fd, ret;
 118
 119         file_fd = lttng_get_unused_fd();
 120         if (file_fd < 0) {
 121                 ret = file_fd;
 122                 goto fd_error;
 123         }
 124
 125         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 126                                           &lttng_tracepoint_list_fops,
 127                                           NULL, O_RDWR);
 128         if (IS_ERR(tracepoint_list_file)) {
 129                 ret = PTR_ERR(tracepoint_list_file);
 130                 goto file_error;
 131         }
 132         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 133         if (ret < 0)
 134                 goto open_error;
 135         fd_install(file_fd, tracepoint_list_file);
 136         return file_fd;
 137
 138 open_error:
 139         fput(tracepoint_list_file);
 140 file_error:
 141         put_unused_fd(file_fd);
 142 fd_error:
 143         return ret;
 144 }
 145
 146 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 147 static inline
 148 int lttng_abi_syscall_list(void)
 149 {
 150         return -ENOSYS;
 151 }
 152 #else
 153 static
 154 int lttng_abi_syscall_list(void)
 155 {
 156         struct file *syscall_list_file;
 157         int file_fd, ret;
 158
 159         file_fd = lttng_get_unused_fd();
 160         if (file_fd < 0) {
 161                 ret = file_fd;
 162                 goto fd_error;
 163         }
 164
 165         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 166                                           &lttng_syscall_list_fops,
 167                                           NULL, O_RDWR);
 168         if (IS_ERR(syscall_list_file)) {
 169                 ret = PTR_ERR(syscall_list_file);
 170                 goto file_error;
 171         }
 172         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 173         if (ret < 0)
 174                 goto open_error;
 175         fd_install(file_fd, syscall_list_file);
 176         return file_fd;
 177
 178 open_error:
 179         fput(syscall_list_file);
 180 file_error:
 181         put_unused_fd(file_fd);
 182 fd_error:
 183         return ret;
 184 }
 185 #endif
 186
 187 static
 188 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 189 {
 190         v->major = LTTNG_MODULES_MAJOR_VERSION;
 191         v->minor = LTTNG_MODULES_MINOR_VERSION;
 192         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 193 }
 194
 195 static
 196 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 197 {
 198         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 199         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 200 }
 201
 202 static
 203 long lttng_abi_add_context(struct file *file,
 204         struct lttng_kernel_context *context_param,
 205         struct lttng_ctx **ctx, struct lttng_session *session)
 206 {
 207
 208         if (session->been_active)
 209                 return -EPERM;
 210
 211         switch (context_param->ctx) {
 212         case LTTNG_KERNEL_CONTEXT_PID:
 213                 return lttng_add_pid_to_ctx(ctx);
 214         case LTTNG_KERNEL_CONTEXT_PRIO:
 215                 return lttng_add_prio_to_ctx(ctx);
 216         case LTTNG_KERNEL_CONTEXT_NICE:
 217                 return lttng_add_nice_to_ctx(ctx);
 218         case LTTNG_KERNEL_CONTEXT_VPID:
 219                 return lttng_add_vpid_to_ctx(ctx);
 220         case LTTNG_KERNEL_CONTEXT_TID:
 221                 return lttng_add_tid_to_ctx(ctx);
 222         case LTTNG_KERNEL_CONTEXT_VTID:
 223                 return lttng_add_vtid_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_PPID:
 225                 return lttng_add_ppid_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_VPPID:
 227                 return lttng_add_vppid_to_ctx(ctx);
 228         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 229                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 230                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 231                                 context_param->u.perf_counter.config,
 232                                 context_param->u.perf_counter.name,
 233                                 ctx);
 234         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 235                 return lttng_add_procname_to_ctx(ctx);
 236         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 237                 return lttng_add_hostname_to_ctx(ctx);
 238         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 239                 return lttng_add_cpu_id_to_ctx(ctx);
 240         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 241                 return lttng_add_interruptible_to_ctx(ctx);
 242         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 243                 return lttng_add_need_reschedule_to_ctx(ctx);
 244         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 245                 return lttng_add_preemptible_to_ctx(ctx);
 246         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 247                 return lttng_add_migratable_to_ctx(ctx);
 248         default:
 249                 return -EINVAL;
 250         }
 251 }
 252
 253 /**
 254  *      lttng_ioctl - lttng syscall through ioctl
 255  *
 256  *      @file: the file
 257  *      @cmd: the command
 258  *      @arg: command arg
 259  *
 260  *      This ioctl implements lttng commands:
 261  *      LTTNG_KERNEL_SESSION
 262  *              Returns a LTTng trace session file descriptor
 263  *      LTTNG_KERNEL_TRACER_VERSION
 264  *              Returns the LTTng kernel tracer version
 265  *      LTTNG_KERNEL_TRACEPOINT_LIST
 266  *              Returns a file descriptor listing available tracepoints
 267  *      LTTNG_KERNEL_WAIT_QUIESCENT
 268  *              Returns after all previously running probes have completed
 269  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 270  *              Returns the LTTng kernel tracer ABI version
 271  *
 272  * The returned session will be deleted when its file descriptor is closed.
 273  */
 274 static
 275 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 276 {
 277         switch (cmd) {
 278         case LTTNG_KERNEL_OLD_SESSION:
 279         case LTTNG_KERNEL_SESSION:
 280                 return lttng_abi_create_session();
 281         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 282         {
 283                 struct lttng_kernel_tracer_version v;
 284                 struct lttng_kernel_old_tracer_version oldv;
 285                 struct lttng_kernel_old_tracer_version *uversion =
 286                         (struct lttng_kernel_old_tracer_version __user *) arg;
 287
 288                 lttng_abi_tracer_version(&v);
 289                 oldv.major = v.major;
 290                 oldv.minor = v.minor;
 291                 oldv.patchlevel = v.patchlevel;
 292
 293                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 294                         return -EFAULT;
 295                 return 0;
 296         }
 297         case LTTNG_KERNEL_TRACER_VERSION:
 298         {
 299                 struct lttng_kernel_tracer_version version;
 300                 struct lttng_kernel_tracer_version *uversion =
 301                         (struct lttng_kernel_tracer_version __user *) arg;
 302
 303                 lttng_abi_tracer_version(&version);
 304
 305                 if (copy_to_user(uversion, &version, sizeof(version)))
 306                         return -EFAULT;
 307                 return 0;
 308         }
 309         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 310         {
 311                 struct lttng_kernel_tracer_abi_version version;
 312                 struct lttng_kernel_tracer_abi_version *uversion =
 313                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 314
 315                 lttng_abi_tracer_abi_version(&version);
 316
 317                 if (copy_to_user(uversion, &version, sizeof(version)))
 318                         return -EFAULT;
 319                 return 0;
 320         }
 321         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 322         case LTTNG_KERNEL_TRACEPOINT_LIST:
 323                 return lttng_abi_tracepoint_list();
 324         case LTTNG_KERNEL_SYSCALL_LIST:
 325                 return lttng_abi_syscall_list();
 326         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 327         case LTTNG_KERNEL_WAIT_QUIESCENT:
 328                 synchronize_trace();
 329                 return 0;
 330         case LTTNG_KERNEL_OLD_CALIBRATE:
 331         {
 332                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 333                         (struct lttng_kernel_old_calibrate __user *) arg;
 334                 struct lttng_kernel_old_calibrate old_calibrate;
 335                 struct lttng_kernel_calibrate calibrate;
 336                 int ret;
 337
 338                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 339                         return -EFAULT;
 340                 calibrate.type = old_calibrate.type;
 341                 ret = lttng_calibrate(&calibrate);
 342                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 343                         return -EFAULT;
 344                 return ret;
 345         }
 346         case LTTNG_KERNEL_CALIBRATE:
 347         {
 348                 struct lttng_kernel_calibrate __user *ucalibrate =
 349                         (struct lttng_kernel_calibrate __user *) arg;
 350                 struct lttng_kernel_calibrate calibrate;
 351                 int ret;
 352
 353                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 354                         return -EFAULT;
 355                 ret = lttng_calibrate(&calibrate);
 356                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 357                         return -EFAULT;
 358                 return ret;
 359         }
 360         default:
 361                 return -ENOIOCTLCMD;
 362         }
 363 }
 364
 365 static const struct file_operations lttng_fops = {
 366         .owner = THIS_MODULE,
 367         .unlocked_ioctl = lttng_ioctl,
 368 #ifdef CONFIG_COMPAT
 369         .compat_ioctl = lttng_ioctl,
 370 #endif
 371 };
 372
 373 static
 374 int lttng_abi_create_channel(struct file *session_file,
 375                              struct lttng_kernel_channel *chan_param,
 376                              enum channel_type channel_type)
 377 {
 378         struct lttng_session *session = session_file->private_data;
 379         const struct file_operations *fops = NULL;
 380         const char *transport_name;
 381         struct lttng_channel *chan;
 382         struct file *chan_file;
 383         int chan_fd;
 384         int ret = 0;
 385
 386         chan_fd = lttng_get_unused_fd();
 387         if (chan_fd < 0) {
 388                 ret = chan_fd;
 389                 goto fd_error;
 390         }
 391         switch (channel_type) {
 392         case PER_CPU_CHANNEL:
 393                 fops = &lttng_channel_fops;
 394                 break;
 395         case METADATA_CHANNEL:
 396                 fops = &lttng_metadata_fops;
 397                 break;
 398         }
 399
 400         chan_file = anon_inode_getfile("[lttng_channel]",
 401                                        fops,
 402                                        NULL, O_RDWR);
 403         if (IS_ERR(chan_file)) {
 404                 ret = PTR_ERR(chan_file);
 405                 goto file_error;
 406         }
 407         switch (channel_type) {
 408         case PER_CPU_CHANNEL:
 409                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 410                         transport_name = chan_param->overwrite ?
 411                                 "relay-overwrite" : "relay-discard";
 412                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 413                         transport_name = chan_param->overwrite ?
 414                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 415                 } else {
 416                         return -EINVAL;
 417                 }
 418                 break;
 419         case METADATA_CHANNEL:
 420                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 421                         transport_name = "relay-metadata";
 422                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 423                         transport_name = "relay-metadata-mmap";
 424                 else
 425                         return -EINVAL;
 426                 break;
 427         default:
 428                 transport_name = "<unknown>";
 429                 break;
 430         }
 431         if (atomic_long_add_unless(&session_file->f_count,
 432                 1, INT_MAX) == INT_MAX) {
 433                 goto refcount_error;
 434         }
 435         /*
 436          * We tolerate no failure path after channel creation. It will stay
 437          * invariant for the rest of the session.
 438          */
 439         chan = lttng_channel_create(session, transport_name, NULL,
 440                                   chan_param->subbuf_size,
 441                                   chan_param->num_subbuf,
 442                                   chan_param->switch_timer_interval,
 443                                   chan_param->read_timer_interval,
 444                                   channel_type);
 445         if (!chan) {
 446                 ret = -EINVAL;
 447                 goto chan_error;
 448         }
 449         chan->file = chan_file;
 450         chan_file->private_data = chan;
 451         fd_install(chan_fd, chan_file);
 452
 453         return chan_fd;
 454
 455 chan_error:
 456         atomic_long_dec(&session_file->f_count);
 457 refcount_error:
 458         fput(chan_file);
 459 file_error:
 460         put_unused_fd(chan_fd);
 461 fd_error:
 462         return ret;
 463 }
 464
 465 /**
 466  *      lttng_session_ioctl - lttng session fd ioctl
 467  *
 468  *      @file: the file
 469  *      @cmd: the command
 470  *      @arg: command arg
 471  *
 472  *      This ioctl implements lttng commands:
 473  *      LTTNG_KERNEL_CHANNEL
 474  *              Returns a LTTng channel file descriptor
 475  *      LTTNG_KERNEL_ENABLE
 476  *              Enables tracing for a session (weak enable)
 477  *      LTTNG_KERNEL_DISABLE
 478  *              Disables tracing for a session (strong disable)
 479  *      LTTNG_KERNEL_METADATA
 480  *              Returns a LTTng metadata file descriptor
 481  *      LTTNG_KERNEL_SESSION_TRACK_PID
 482  *              Add PID to session tracker
 483  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 484  *              Remove PID from session tracker
 485  *
 486  * The returned channel will be deleted when its file descriptor is closed.
 487  */
 488 static
 489 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 490 {
 491         struct lttng_session *session = file->private_data;
 492
 493         switch (cmd) {
 494         case LTTNG_KERNEL_OLD_CHANNEL:
 495         {
 496                 struct lttng_kernel_channel chan_param;
 497                 struct lttng_kernel_old_channel old_chan_param;
 498
 499                 if (copy_from_user(&old_chan_param,
 500                                 (struct lttng_kernel_old_channel __user *) arg,
 501                                 sizeof(struct lttng_kernel_old_channel)))
 502                         return -EFAULT;
 503                 chan_param.overwrite = old_chan_param.overwrite;
 504                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 505                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 506                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 507                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 508                 chan_param.output = old_chan_param.output;
 509
 510                 return lttng_abi_create_channel(file, &chan_param,
 511                                 PER_CPU_CHANNEL);
 512         }
 513         case LTTNG_KERNEL_CHANNEL:
 514         {
 515                 struct lttng_kernel_channel chan_param;
 516
 517                 if (copy_from_user(&chan_param,
 518                                 (struct lttng_kernel_channel __user *) arg,
 519                                 sizeof(struct lttng_kernel_channel)))
 520                         return -EFAULT;
 521                 return lttng_abi_create_channel(file, &chan_param,
 522                                 PER_CPU_CHANNEL);
 523         }
 524         case LTTNG_KERNEL_OLD_SESSION_START:
 525         case LTTNG_KERNEL_OLD_ENABLE:
 526         case LTTNG_KERNEL_SESSION_START:
 527         case LTTNG_KERNEL_ENABLE:
 528                 return lttng_session_enable(session);
 529         case LTTNG_KERNEL_OLD_SESSION_STOP:
 530         case LTTNG_KERNEL_OLD_DISABLE:
 531         case LTTNG_KERNEL_SESSION_STOP:
 532         case LTTNG_KERNEL_DISABLE:
 533                 return lttng_session_disable(session);
 534         case LTTNG_KERNEL_OLD_METADATA:
 535         {
 536                 struct lttng_kernel_channel chan_param;
 537                 struct lttng_kernel_old_channel old_chan_param;
 538
 539                 if (copy_from_user(&old_chan_param,
 540                                 (struct lttng_kernel_old_channel __user *) arg,
 541                                 sizeof(struct lttng_kernel_old_channel)))
 542                         return -EFAULT;
 543                 chan_param.overwrite = old_chan_param.overwrite;
 544                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 545                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 546                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 547                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 548                 chan_param.output = old_chan_param.output;
 549
 550                 return lttng_abi_create_channel(file, &chan_param,
 551                                 METADATA_CHANNEL);
 552         }
 553         case LTTNG_KERNEL_METADATA:
 554         {
 555                 struct lttng_kernel_channel chan_param;
 556
 557                 if (copy_from_user(&chan_param,
 558                                         (struct lttng_kernel_channel __user *) arg,
 559                                         sizeof(struct lttng_kernel_channel)))
 560                         return -EFAULT;
 561                 return lttng_abi_create_channel(file, &chan_param,
 562                                 METADATA_CHANNEL);
 563         }
 564         case LTTNG_KERNEL_SESSION_TRACK_PID:
 565                 return lttng_session_track_pid(session, (int) arg);
 566         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 567                 return lttng_session_untrack_pid(session, (int) arg);
 568         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 569                 return lttng_session_list_tracker_pids(session);
 570         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 571                 return lttng_session_metadata_regenerate(session);
 572         default:
 573                 return -ENOIOCTLCMD;
 574         }
 575 }
 576
 577 /*
 578  * Called when the last file reference is dropped.
 579  *
 580  * Big fat note: channels and events are invariant for the whole session after
 581  * their creation. So this session destruction also destroys all channel and
 582  * event structures specific to this session (they are not destroyed when their
 583  * individual file is released).
 584  */
 585 static
 586 int lttng_session_release(struct inode *inode, struct file *file)
 587 {
 588         struct lttng_session *session = file->private_data;
 589
 590         if (session)
 591                 lttng_session_destroy(session);
 592         return 0;
 593 }
 594
 595 static const struct file_operations lttng_session_fops = {
 596         .owner = THIS_MODULE,
 597         .release = lttng_session_release,
 598         .unlocked_ioctl = lttng_session_ioctl,
 599 #ifdef CONFIG_COMPAT
 600         .compat_ioctl = lttng_session_ioctl,
 601 #endif
 602 };
 603
 604 /**
 605  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 606  *      @filp: the file
 607  *      @wait: poll table
 608  *
 609  *      Handles the poll operations for the metadata channels.
 610  */
 611 static
 612 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 613                 poll_table *wait)
 614 {
 615         struct lttng_metadata_stream *stream = filp->private_data;
 616         struct lib_ring_buffer *buf = stream->priv;
 617         int finalized;
 618         unsigned int mask = 0;
 619
 620         if (filp->f_mode & FMODE_READ) {
 621                 poll_wait_set_exclusive(wait);
 622                 poll_wait(filp, &stream->read_wait, wait);
 623
 624                 finalized = stream->finalized;
 625
 626                 /*
 627                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 628                  * ordering finalized load before offsets loads.
 629                  */
 630                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 631
 632                 if (finalized)
 633                         mask |= POLLHUP;
 634
 635                 mutex_lock(&stream->metadata_cache->lock);
 636                 if (stream->metadata_cache->metadata_written >
 637                                 stream->metadata_out)
 638                         mask |= POLLIN;
 639                 mutex_unlock(&stream->metadata_cache->lock);
 640         }
 641
 642         return mask;
 643 }
 644
 645 static
 646 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 647                 unsigned int cmd, unsigned long arg)
 648 {
 649         struct lttng_metadata_stream *stream = filp->private_data;
 650
 651         stream->metadata_out = stream->metadata_in;
 652 }
 653
 654 static
 655 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 656                 unsigned int cmd, unsigned long arg)
 657 {
 658         int ret;
 659         struct lttng_metadata_stream *stream = filp->private_data;
 660         struct lib_ring_buffer *buf = stream->priv;
 661
 662         switch (cmd) {
 663         case RING_BUFFER_GET_NEXT_SUBBUF:
 664         {
 665                 struct lttng_metadata_stream *stream = filp->private_data;
 666                 struct lib_ring_buffer *buf = stream->priv;
 667                 struct channel *chan = buf->backend.chan;
 668
 669                 ret = lttng_metadata_output_channel(stream, chan);
 670                 if (ret > 0) {
 671                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 672                         ret = 0;
 673                 } else if (ret < 0)
 674                         goto err;
 675                 break;
 676         }
 677         case RING_BUFFER_GET_SUBBUF:
 678         {
 679                 /*
 680                  * Random access is not allowed for metadata channel.
 681                  */
 682                 return -ENOSYS;
 683         }
 684         case RING_BUFFER_FLUSH:
 685         {
 686                 struct lttng_metadata_stream *stream = filp->private_data;
 687                 struct lib_ring_buffer *buf = stream->priv;
 688                 struct channel *chan = buf->backend.chan;
 689
 690                 /*
 691                  * Before doing the actual ring buffer flush, write up to one
 692                  * packet of metadata in the ring buffer.
 693                  */
 694                 ret = lttng_metadata_output_channel(stream, chan);
 695                 if (ret < 0)
 696                         goto err;
 697                 break;
 698         }
 699         case RING_BUFFER_GET_METADATA_VERSION:
 700         {
 701                 struct lttng_metadata_stream *stream = filp->private_data;
 702
 703                 return put_u64(stream->version, arg);
 704         }
 705         case RING_BUFFER_SNAPSHOT:
 706         {
 707                 /*
 708                  * Force the buffer to quiescent so the ring buffer
 709                  * don't attempt to perform a SWITCH_FLUSH, which would
 710                  * desynchronize the client accounting of the amount of
 711                  * data available in the buffer from the ring buffer
 712                  * view.
 713                  */
 714                 buf->quiescent = true;
 715                 break;
 716         }
 717         default:
 718                 break;
 719         }
 720         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 721
 722         /* Performing lib ring buffer ioctl after our own. */
 723         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 724         if (ret < 0)
 725                 goto err;
 726
 727         switch (cmd) {
 728         case RING_BUFFER_PUT_NEXT_SUBBUF:
 729         {
 730                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 731                                 cmd, arg);
 732                 break;
 733         }
 734         default:
 735                 break;
 736         }
 737 err:
 738         return ret;
 739 }
 740
 741 #ifdef CONFIG_COMPAT
 742 static
 743 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 744                 unsigned int cmd, unsigned long arg)
 745 {
 746         int ret;
 747         struct lttng_metadata_stream *stream = filp->private_data;
 748         struct lib_ring_buffer *buf = stream->priv;
 749
 750         switch (cmd) {
 751         case RING_BUFFER_GET_NEXT_SUBBUF:
 752         {
 753                 struct lttng_metadata_stream *stream = filp->private_data;
 754                 struct lib_ring_buffer *buf = stream->priv;
 755                 struct channel *chan = buf->backend.chan;
 756
 757                 ret = lttng_metadata_output_channel(stream, chan);
 758                 if (ret > 0) {
 759                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 760                         ret = 0;
 761                 } else if (ret < 0)
 762                         goto err;
 763                 break;
 764         }
 765         case RING_BUFFER_GET_SUBBUF:
 766         {
 767                 /*
 768                  * Random access is not allowed for metadata channel.
 769                  */
 770                 return -ENOSYS;
 771         }
 772         case RING_BUFFER_FLUSH:
 773         {
 774                 struct lttng_metadata_stream *stream = filp->private_data;
 775                 struct lib_ring_buffer *buf = stream->priv;
 776                 struct channel *chan = buf->backend.chan;
 777
 778                 /*
 779                  * Before doing the actual ring buffer flush, write up to one
 780                  * packet of metadata in the ring buffer.
 781                  */
 782                 ret = lttng_metadata_output_channel(stream, chan);
 783                 if (ret < 0)
 784                         goto err;
 785                 break;
 786         }
 787         case RING_BUFFER_GET_METADATA_VERSION:
 788         {
 789                 struct lttng_metadata_stream *stream = filp->private_data;
 790
 791                 return put_u64(stream->version, arg);
 792         }
 793         case RING_BUFFER_SNAPSHOT:
 794         {
 795                 /*
 796                  * Force the buffer to quiescent so the ring buffer
 797                  * don't attempt to perform a SWITCH_FLUSH, which would
 798                  * desynchronize the client accounting of the amount of
 799                  * data available in the buffer from the ring buffer
 800                  * view.
 801                  */
 802                 buf->quiescent = true;
 803                 break;
 804         }
 805         default:
 806                 break;
 807         }
 808         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 809
 810         /* Performing lib ring buffer ioctl after our own. */
 811         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 812         if (ret < 0)
 813                 goto err;
 814
 815         switch (cmd) {
 816         case RING_BUFFER_PUT_NEXT_SUBBUF:
 817         {
 818                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 819                                 cmd, arg);
 820                 break;
 821         }
 822         default:
 823                 break;
 824         }
 825 err:
 826         return ret;
 827 }
 828 #endif
 829
 830 /*
 831  * This is not used by anonymous file descriptors. This code is left
 832  * there if we ever want to implement an inode with open() operation.
 833  */
 834 static
 835 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 836 {
 837         struct lttng_metadata_stream *stream = inode->i_private;
 838         struct lib_ring_buffer *buf = stream->priv;
 839
 840         file->private_data = buf;
 841         /*
 842          * Since life-time of metadata cache differs from that of
 843          * session, we need to keep our own reference on the transport.
 844          */
 845         if (!try_module_get(stream->transport->owner)) {
 846                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 847                 return -EBUSY;
 848         }
 849         return lib_ring_buffer_open(inode, file, buf);
 850 }
 851
 852 static
 853 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 854 {
 855         struct lttng_metadata_stream *stream = file->private_data;
 856         struct lib_ring_buffer *buf = stream->priv;
 857
 858         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 859         module_put(stream->transport->owner);
 860         return lib_ring_buffer_release(inode, file, buf);
 861 }
 862
 863 static
 864 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 865                 struct pipe_inode_info *pipe, size_t len,
 866                 unsigned int flags)
 867 {
 868         struct lttng_metadata_stream *stream = in->private_data;
 869         struct lib_ring_buffer *buf = stream->priv;
 870
 871         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 872                         flags, buf);
 873 }
 874
 875 static
 876 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 877                 struct vm_area_struct *vma)
 878 {
 879         struct lttng_metadata_stream *stream = filp->private_data;
 880         struct lib_ring_buffer *buf = stream->priv;
 881
 882         return lib_ring_buffer_mmap(filp, vma, buf);
 883 }
 884
 885 static
 886 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 887         .owner = THIS_MODULE,
 888         .open = lttng_metadata_ring_buffer_open,
 889         .release = lttng_metadata_ring_buffer_release,
 890         .poll = lttng_metadata_ring_buffer_poll,
 891         .splice_read = lttng_metadata_ring_buffer_splice_read,
 892         .mmap = lttng_metadata_ring_buffer_mmap,
 893         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 894         .llseek = vfs_lib_ring_buffer_no_llseek,
 895 #ifdef CONFIG_COMPAT
 896         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 897 #endif
 898 };
 899
 900 static
 901 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 902                 const struct file_operations *fops)
 903 {
 904         int stream_fd, ret;
 905         struct file *stream_file;
 906
 907         stream_fd = lttng_get_unused_fd();
 908         if (stream_fd < 0) {
 909                 ret = stream_fd;
 910                 goto fd_error;
 911         }
 912         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 913                         stream_priv, O_RDWR);
 914         if (IS_ERR(stream_file)) {
 915                 ret = PTR_ERR(stream_file);
 916                 goto file_error;
 917         }
 918         /*
 919          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 920          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 921          * file descriptor, so we set FMODE_PREAD here.
 922          */
 923         stream_file->f_mode |= FMODE_PREAD;
 924         fd_install(stream_fd, stream_file);
 925         /*
 926          * The stream holds a reference to the channel within the generic ring
 927          * buffer library, so no need to hold a refcount on the channel and
 928          * session files here.
 929          */
 930         return stream_fd;
 931
 932 file_error:
 933         put_unused_fd(stream_fd);
 934 fd_error:
 935         return ret;
 936 }
 937
 938 static
 939 int lttng_abi_open_stream(struct file *channel_file)
 940 {
 941         struct lttng_channel *channel = channel_file->private_data;
 942         struct lib_ring_buffer *buf;
 943         int ret;
 944         void *stream_priv;
 945
 946         buf = channel->ops->buffer_read_open(channel->chan);
 947         if (!buf)
 948                 return -ENOENT;
 949
 950         stream_priv = buf;
 951         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 952                         &lttng_stream_ring_buffer_file_operations);
 953         if (ret < 0)
 954                 goto fd_error;
 955
 956         return ret;
 957
 958 fd_error:
 959         channel->ops->buffer_read_close(buf);
 960         return ret;
 961 }
 962
 963 static
 964 int lttng_abi_open_metadata_stream(struct file *channel_file)
 965 {
 966         struct lttng_channel *channel = channel_file->private_data;
 967         struct lttng_session *session = channel->session;
 968         struct lib_ring_buffer *buf;
 969         int ret;
 970         struct lttng_metadata_stream *metadata_stream;
 971         void *stream_priv;
 972
 973         buf = channel->ops->buffer_read_open(channel->chan);
 974         if (!buf)
 975                 return -ENOENT;
 976
 977         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 978                         GFP_KERNEL);
 979         if (!metadata_stream) {
 980                 ret = -ENOMEM;
 981                 goto nomem;
 982         }
 983         metadata_stream->metadata_cache = session->metadata_cache;
 984         init_waitqueue_head(&metadata_stream->read_wait);
 985         metadata_stream->priv = buf;
 986         stream_priv = metadata_stream;
 987         metadata_stream->transport = channel->transport;
 988
 989         /*
 990          * Since life-time of metadata cache differs from that of
 991          * session, we need to keep our own reference on the transport.
 992          */
 993         if (!try_module_get(metadata_stream->transport->owner)) {
 994                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 995                 ret = -EINVAL;
 996                 goto notransport;
 997         }
 998
 999         if (!lttng_kref_get(&session->metadata_cache->refcount))
1000                 goto kref_error;
1001         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1002                         &lttng_metadata_ring_buffer_file_operations);
1003         if (ret < 0)
1004                 goto fd_error;
1005
1006         list_add(&metadata_stream->list,
1007                 &session->metadata_cache->metadata_stream);
1008         return ret;
1009
1010 fd_error:
1011         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1012 kref_error:
1013         module_put(metadata_stream->transport->owner);
1014 notransport:
1015         kfree(metadata_stream);
1016 nomem:
1017         channel->ops->buffer_read_close(buf);
1018         return ret;
1019 }
1020
1021 static
1022 int lttng_abi_create_event(struct file *channel_file,
1023                            struct lttng_kernel_event *event_param)
1024 {
1025         struct lttng_channel *channel = channel_file->private_data;
1026         int event_fd, ret;
1027         struct file *event_file;
1028         void *priv;
1029
1030         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1031         switch (event_param->instrumentation) {
1032         case LTTNG_KERNEL_KRETPROBE:
1033                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1034                 break;
1035         case LTTNG_KERNEL_KPROBE:
1036                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1037                 break;
1038         case LTTNG_KERNEL_FUNCTION:
1039                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1040                 break;
1041         default:
1042                 break;
1043         }
1044         event_fd = lttng_get_unused_fd();
1045         if (event_fd < 0) {
1046                 ret = event_fd;
1047                 goto fd_error;
1048         }
1049         event_file = anon_inode_getfile("[lttng_event]",
1050                                         &lttng_event_fops,
1051                                         NULL, O_RDWR);
1052         if (IS_ERR(event_file)) {
1053                 ret = PTR_ERR(event_file);
1054                 goto file_error;
1055         }
1056         /* The event holds a reference on the channel */
1057         if (atomic_long_add_unless(&channel_file->f_count,
1058                 1, INT_MAX) == INT_MAX) {
1059                 ret = -EOVERFLOW;
1060                 goto refcount_error;
1061         }
1062         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1063                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1064                 struct lttng_enabler *enabler;
1065
1066                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1067                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1068                                 event_param, channel);
1069                 } else {
1070                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1071                                 event_param, channel);
1072                 }
1073                 priv = enabler;
1074         } else {
1075                 struct lttng_event *event;
1076
1077                 /*
1078                  * We tolerate no failure path after event creation. It
1079                  * will stay invariant for the rest of the session.
1080                  */
1081                 event = lttng_event_create(channel, event_param,
1082                                 NULL, NULL,
1083                                 event_param->instrumentation);
1084                 WARN_ON_ONCE(!event);
1085                 if (IS_ERR(event)) {
1086                         ret = PTR_ERR(event);
1087                         goto event_error;
1088                 }
1089                 priv = event;
1090         }
1091         event_file->private_data = priv;
1092         fd_install(event_fd, event_file);
1093         return event_fd;
1094
1095 event_error:
1096         atomic_long_dec(&channel_file->f_count);
1097 refcount_error:
1098         fput(event_file);
1099 file_error:
1100         put_unused_fd(event_fd);
1101 fd_error:
1102         return ret;
1103 }
1104
1105 /**
1106  *      lttng_channel_ioctl - lttng syscall through ioctl
1107  *
1108  *      @file: the file
1109  *      @cmd: the command
1110  *      @arg: command arg
1111  *
1112  *      This ioctl implements lttng commands:
1113  *      LTTNG_KERNEL_STREAM
1114  *              Returns an event stream file descriptor or failure.
1115  *              (typically, one event stream records events from one CPU)
1116  *      LTTNG_KERNEL_EVENT
1117  *              Returns an event file descriptor or failure.
1118  *      LTTNG_KERNEL_CONTEXT
1119  *              Prepend a context field to each event in the channel
1120  *      LTTNG_KERNEL_ENABLE
1121  *              Enable recording for events in this channel (weak enable)
1122  *      LTTNG_KERNEL_DISABLE
1123  *              Disable recording for events in this channel (strong disable)
1124  *
1125  * Channel and event file descriptors also hold a reference on the session.
1126  */
1127 static
1128 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1129 {
1130         struct lttng_channel *channel = file->private_data;
1131
1132         switch (cmd) {
1133         case LTTNG_KERNEL_OLD_STREAM:
1134         case LTTNG_KERNEL_STREAM:
1135                 return lttng_abi_open_stream(file);
1136         case LTTNG_KERNEL_OLD_EVENT:
1137         {
1138                 struct lttng_kernel_event *uevent_param;
1139                 struct lttng_kernel_old_event *old_uevent_param;
1140                 int ret;
1141
1142                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1143                                 GFP_KERNEL);
1144                 if (!uevent_param) {
1145                         ret = -ENOMEM;
1146                         goto old_event_end;
1147                 }
1148                 old_uevent_param = kmalloc(
1149                                 sizeof(struct lttng_kernel_old_event),
1150                                 GFP_KERNEL);
1151                 if (!old_uevent_param) {
1152                         ret = -ENOMEM;
1153                         goto old_event_error_free_param;
1154                 }
1155                 if (copy_from_user(old_uevent_param,
1156                                 (struct lttng_kernel_old_event __user *) arg,
1157                                 sizeof(struct lttng_kernel_old_event))) {
1158                         ret = -EFAULT;
1159                         goto old_event_error_free_old_param;
1160                 }
1161
1162                 memcpy(uevent_param->name, old_uevent_param->name,
1163                                 sizeof(uevent_param->name));
1164                 uevent_param->instrumentation =
1165                         old_uevent_param->instrumentation;
1166
1167                 switch (old_uevent_param->instrumentation) {
1168                 case LTTNG_KERNEL_KPROBE:
1169                         uevent_param->u.kprobe.addr =
1170                                 old_uevent_param->u.kprobe.addr;
1171                         uevent_param->u.kprobe.offset =
1172                                 old_uevent_param->u.kprobe.offset;
1173                         memcpy(uevent_param->u.kprobe.symbol_name,
1174                                 old_uevent_param->u.kprobe.symbol_name,
1175                                 sizeof(uevent_param->u.kprobe.symbol_name));
1176                         break;
1177                 case LTTNG_KERNEL_KRETPROBE:
1178                         uevent_param->u.kretprobe.addr =
1179                                 old_uevent_param->u.kretprobe.addr;
1180                         uevent_param->u.kretprobe.offset =
1181                                 old_uevent_param->u.kretprobe.offset;
1182                         memcpy(uevent_param->u.kretprobe.symbol_name,
1183                                 old_uevent_param->u.kretprobe.symbol_name,
1184                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1185                         break;
1186                 case LTTNG_KERNEL_FUNCTION:
1187                         memcpy(uevent_param->u.ftrace.symbol_name,
1188                                         old_uevent_param->u.ftrace.symbol_name,
1189                                         sizeof(uevent_param->u.ftrace.symbol_name));
1190                         break;
1191                 default:
1192                         break;
1193                 }
1194                 ret = lttng_abi_create_event(file, uevent_param);
1195
1196 old_event_error_free_old_param:
1197                 kfree(old_uevent_param);
1198 old_event_error_free_param:
1199                 kfree(uevent_param);
1200 old_event_end:
1201                 return ret;
1202         }
1203         case LTTNG_KERNEL_EVENT:
1204         {
1205                 struct lttng_kernel_event uevent_param;
1206
1207                 if (copy_from_user(&uevent_param,
1208                                 (struct lttng_kernel_event __user *) arg,
1209                                 sizeof(uevent_param)))
1210                         return -EFAULT;
1211                 return lttng_abi_create_event(file, &uevent_param);
1212         }
1213         case LTTNG_KERNEL_OLD_CONTEXT:
1214         {
1215                 struct lttng_kernel_context *ucontext_param;
1216                 struct lttng_kernel_old_context *old_ucontext_param;
1217                 int ret;
1218
1219                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1220                                 GFP_KERNEL);
1221                 if (!ucontext_param) {
1222                         ret = -ENOMEM;
1223                         goto old_ctx_end;
1224                 }
1225                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1226                                 GFP_KERNEL);
1227                 if (!old_ucontext_param) {
1228                         ret = -ENOMEM;
1229                         goto old_ctx_error_free_param;
1230                 }
1231
1232                 if (copy_from_user(old_ucontext_param,
1233                                 (struct lttng_kernel_old_context __user *) arg,
1234                                 sizeof(struct lttng_kernel_old_context))) {
1235                         ret = -EFAULT;
1236                         goto old_ctx_error_free_old_param;
1237                 }
1238                 ucontext_param->ctx = old_ucontext_param->ctx;
1239                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1240                                 sizeof(ucontext_param->padding));
1241                 /* only type that uses the union */
1242                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1243                         ucontext_param->u.perf_counter.type =
1244                                 old_ucontext_param->u.perf_counter.type;
1245                         ucontext_param->u.perf_counter.config =
1246                                 old_ucontext_param->u.perf_counter.config;
1247                         memcpy(ucontext_param->u.perf_counter.name,
1248                                 old_ucontext_param->u.perf_counter.name,
1249                                 sizeof(ucontext_param->u.perf_counter.name));
1250                 }
1251
1252                 ret = lttng_abi_add_context(file,
1253                                 ucontext_param,
1254                                 &channel->ctx, channel->session);
1255
1256 old_ctx_error_free_old_param:
1257                 kfree(old_ucontext_param);
1258 old_ctx_error_free_param:
1259                 kfree(ucontext_param);
1260 old_ctx_end:
1261                 return ret;
1262         }
1263         case LTTNG_KERNEL_CONTEXT:
1264         {
1265                 struct lttng_kernel_context ucontext_param;
1266
1267                 if (copy_from_user(&ucontext_param,
1268                                 (struct lttng_kernel_context __user *) arg,
1269                                 sizeof(ucontext_param)))
1270                         return -EFAULT;
1271                 return lttng_abi_add_context(file,
1272                                 &ucontext_param,
1273                                 &channel->ctx, channel->session);
1274         }
1275         case LTTNG_KERNEL_OLD_ENABLE:
1276         case LTTNG_KERNEL_ENABLE:
1277                 return lttng_channel_enable(channel);
1278         case LTTNG_KERNEL_OLD_DISABLE:
1279         case LTTNG_KERNEL_DISABLE:
1280                 return lttng_channel_disable(channel);
1281         case LTTNG_KERNEL_SYSCALL_MASK:
1282                 return lttng_channel_syscall_mask(channel,
1283                         (struct lttng_kernel_syscall_mask __user *) arg);
1284         default:
1285                 return -ENOIOCTLCMD;
1286         }
1287
1288 }
1289
1290 /**
1291  *      lttng_metadata_ioctl - lttng syscall through ioctl
1292  *
1293  *      @file: the file
1294  *      @cmd: the command
1295  *      @arg: command arg
1296  *
1297  *      This ioctl implements lttng commands:
1298  *      LTTNG_KERNEL_STREAM
1299  *              Returns an event stream file descriptor or failure.
1300  *
1301  * Channel and event file descriptors also hold a reference on the session.
1302  */
1303 static
1304 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1305 {
1306         switch (cmd) {
1307         case LTTNG_KERNEL_OLD_STREAM:
1308         case LTTNG_KERNEL_STREAM:
1309                 return lttng_abi_open_metadata_stream(file);
1310         default:
1311                 return -ENOIOCTLCMD;
1312         }
1313 }
1314
1315 /**
1316  *      lttng_channel_poll - lttng stream addition/removal monitoring
1317  *
1318  *      @file: the file
1319  *      @wait: poll table
1320  */
1321 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1322 {
1323         struct lttng_channel *channel = file->private_data;
1324         unsigned int mask = 0;
1325
1326         if (file->f_mode & FMODE_READ) {
1327                 poll_wait_set_exclusive(wait);
1328                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1329                           wait);
1330
1331                 if (channel->ops->is_disabled(channel->chan))
1332                         return POLLERR;
1333                 if (channel->ops->is_finalized(channel->chan))
1334                         return POLLHUP;
1335                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1336                         return POLLIN | POLLRDNORM;
1337                 return 0;
1338         }
1339         return mask;
1340
1341 }
1342
1343 static
1344 int lttng_channel_release(struct inode *inode, struct file *file)
1345 {
1346         struct lttng_channel *channel = file->private_data;
1347
1348         if (channel)
1349                 fput(channel->session->file);
1350         return 0;
1351 }
1352
1353 static
1354 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1355 {
1356         struct lttng_channel *channel = file->private_data;
1357
1358         if (channel) {
1359                 fput(channel->session->file);
1360                 lttng_metadata_channel_destroy(channel);
1361         }
1362
1363         return 0;
1364 }
1365
1366 static const struct file_operations lttng_channel_fops = {
1367         .owner = THIS_MODULE,
1368         .release = lttng_channel_release,
1369         .poll = lttng_channel_poll,
1370         .unlocked_ioctl = lttng_channel_ioctl,
1371 #ifdef CONFIG_COMPAT
1372         .compat_ioctl = lttng_channel_ioctl,
1373 #endif
1374 };
1375
1376 static const struct file_operations lttng_metadata_fops = {
1377         .owner = THIS_MODULE,
1378         .release = lttng_metadata_channel_release,
1379         .unlocked_ioctl = lttng_metadata_ioctl,
1380 #ifdef CONFIG_COMPAT
1381         .compat_ioctl = lttng_metadata_ioctl,
1382 #endif
1383 };
1384
1385 /**
1386  *      lttng_event_ioctl - lttng syscall through ioctl
1387  *
1388  *      @file: the file
1389  *      @cmd: the command
1390  *      @arg: command arg
1391  *
1392  *      This ioctl implements lttng commands:
1393  *      LTTNG_KERNEL_CONTEXT
1394  *              Prepend a context field to each record of this event
1395  *      LTTNG_KERNEL_ENABLE
1396  *              Enable recording for this event (weak enable)
1397  *      LTTNG_KERNEL_DISABLE
1398  *              Disable recording for this event (strong disable)
1399  */
1400 static
1401 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1402 {
1403         struct lttng_event *event;
1404         struct lttng_enabler *enabler;
1405         enum lttng_event_type *evtype = file->private_data;
1406
1407         switch (cmd) {
1408         case LTTNG_KERNEL_OLD_CONTEXT:
1409         {
1410                 /* Not implemented */
1411                 return -ENOSYS;
1412         }
1413         case LTTNG_KERNEL_CONTEXT:
1414         {
1415                 /* Not implemented */
1416                 return -ENOSYS;
1417         }
1418         case LTTNG_KERNEL_OLD_ENABLE:
1419         case LTTNG_KERNEL_ENABLE:
1420                 switch (*evtype) {
1421                 case LTTNG_TYPE_EVENT:
1422                         event = file->private_data;
1423                         return lttng_event_enable(event);
1424                 case LTTNG_TYPE_ENABLER:
1425                         enabler = file->private_data;
1426                         return lttng_enabler_enable(enabler);
1427                 default:
1428                         WARN_ON_ONCE(1);
1429                         return -ENOSYS;
1430                 }
1431         case LTTNG_KERNEL_OLD_DISABLE:
1432         case LTTNG_KERNEL_DISABLE:
1433                 switch (*evtype) {
1434                 case LTTNG_TYPE_EVENT:
1435                         event = file->private_data;
1436                         return lttng_event_disable(event);
1437                 case LTTNG_TYPE_ENABLER:
1438                         enabler = file->private_data;
1439                         return lttng_enabler_disable(enabler);
1440                 default:
1441                         WARN_ON_ONCE(1);
1442                         return -ENOSYS;
1443                 }
1444         case LTTNG_KERNEL_FILTER:
1445                 switch (*evtype) {
1446                 case LTTNG_TYPE_EVENT:
1447                         return -EINVAL;
1448                 case LTTNG_TYPE_ENABLER:
1449                 {
1450                         enabler = file->private_data;
1451                         return lttng_enabler_attach_bytecode(enabler,
1452                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1453                 }
1454
1455                 }
1456         default:
1457                 return -ENOIOCTLCMD;
1458         }
1459 }
1460
1461 static
1462 int lttng_event_release(struct inode *inode, struct file *file)
1463 {
1464         struct lttng_event *event;
1465         struct lttng_enabler *enabler;
1466         enum lttng_event_type *evtype = file->private_data;
1467
1468         if (!evtype)
1469                 return 0;
1470
1471         switch (*evtype) {
1472         case LTTNG_TYPE_EVENT:
1473                 event = file->private_data;
1474                 if (event)
1475                         fput(event->chan->file);
1476                 break;
1477         case LTTNG_TYPE_ENABLER:
1478                 enabler = file->private_data;
1479                 if (enabler)
1480                         fput(enabler->chan->file);
1481                 break;
1482         default:
1483                 WARN_ON_ONCE(1);
1484                 break;
1485         }
1486
1487         return 0;
1488 }
1489
1490 /* TODO: filter control ioctl */
1491 static const struct file_operations lttng_event_fops = {
1492         .owner = THIS_MODULE,
1493         .release = lttng_event_release,
1494         .unlocked_ioctl = lttng_event_ioctl,
1495 #ifdef CONFIG_COMPAT
1496         .compat_ioctl = lttng_event_ioctl,
1497 #endif
1498 };
1499
1500 static int put_u64(uint64_t val, unsigned long arg)
1501 {
1502         return put_user(val, (uint64_t __user *) arg);
1503 }
1504
1505 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1506                 unsigned int cmd, unsigned long arg)
1507 {
1508         struct lib_ring_buffer *buf = filp->private_data;
1509         struct channel *chan = buf->backend.chan;
1510         const struct lib_ring_buffer_config *config = &chan->backend.config;
1511         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1512         int ret;
1513
1514         if (atomic_read(&chan->record_disabled))
1515                 return -EIO;
1516
1517         switch (cmd) {
1518         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1519         {
1520                 uint64_t ts;
1521
1522                 ret = ops->timestamp_begin(config, buf, &ts);
1523                 if (ret < 0)
1524                         goto error;
1525                 return put_u64(ts, arg);
1526         }
1527         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1528         {
1529                 uint64_t ts;
1530
1531                 ret = ops->timestamp_end(config, buf, &ts);
1532                 if (ret < 0)
1533                         goto error;
1534                 return put_u64(ts, arg);
1535         }
1536         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1537         {
1538                 uint64_t ed;
1539
1540                 ret = ops->events_discarded(config, buf, &ed);
1541                 if (ret < 0)
1542                         goto error;
1543                 return put_u64(ed, arg);
1544         }
1545         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1546         {
1547                 uint64_t cs;
1548
1549                 ret = ops->content_size(config, buf, &cs);
1550                 if (ret < 0)
1551                         goto error;
1552                 return put_u64(cs, arg);
1553         }
1554         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1555         {
1556                 uint64_t ps;
1557
1558                 ret = ops->packet_size(config, buf, &ps);
1559                 if (ret < 0)
1560                         goto error;
1561                 return put_u64(ps, arg);
1562         }
1563         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1564         {
1565                 uint64_t si;
1566
1567                 ret = ops->stream_id(config, buf, &si);
1568                 if (ret < 0)
1569                         goto error;
1570                 return put_u64(si, arg);
1571         }
1572         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1573         {
1574                 uint64_t ts;
1575
1576                 ret = ops->current_timestamp(config, buf, &ts);
1577                 if (ret < 0)
1578                         goto error;
1579                 return put_u64(ts, arg);
1580         }
1581         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1582         {
1583                 uint64_t seq;
1584
1585                 ret = ops->sequence_number(config, buf, &seq);
1586                 if (ret < 0)
1587                         goto error;
1588                 return put_u64(seq, arg);
1589         }
1590         case LTTNG_RING_BUFFER_INSTANCE_ID:
1591         {
1592                 uint64_t id;
1593
1594                 ret = ops->instance_id(config, buf, &id);
1595                 if (ret < 0)
1596                         goto error;
1597                 return put_u64(id, arg);
1598         }
1599         default:
1600                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1601                                 cmd, arg);
1602         }
1603
1604 error:
1605         return -ENOSYS;
1606 }
1607
1608 #ifdef CONFIG_COMPAT
1609 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1610                 unsigned int cmd, unsigned long arg)
1611 {
1612         struct lib_ring_buffer *buf = filp->private_data;
1613         struct channel *chan = buf->backend.chan;
1614         const struct lib_ring_buffer_config *config = &chan->backend.config;
1615         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1616         int ret;
1617
1618         if (atomic_read(&chan->record_disabled))
1619                 return -EIO;
1620
1621         switch (cmd) {
1622         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1623         {
1624                 uint64_t ts;
1625
1626                 ret = ops->timestamp_begin(config, buf, &ts);
1627                 if (ret < 0)
1628                         goto error;
1629                 return put_u64(ts, arg);
1630         }
1631         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1632         {
1633                 uint64_t ts;
1634
1635                 ret = ops->timestamp_end(config, buf, &ts);
1636                 if (ret < 0)
1637                         goto error;
1638                 return put_u64(ts, arg);
1639         }
1640         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1641         {
1642                 uint64_t ed;
1643
1644                 ret = ops->events_discarded(config, buf, &ed);
1645                 if (ret < 0)
1646                         goto error;
1647                 return put_u64(ed, arg);
1648         }
1649         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1650         {
1651                 uint64_t cs;
1652
1653                 ret = ops->content_size(config, buf, &cs);
1654                 if (ret < 0)
1655                         goto error;
1656                 return put_u64(cs, arg);
1657         }
1658         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1659         {
1660                 uint64_t ps;
1661
1662                 ret = ops->packet_size(config, buf, &ps);
1663                 if (ret < 0)
1664                         goto error;
1665                 return put_u64(ps, arg);
1666         }
1667         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1668         {
1669                 uint64_t si;
1670
1671                 ret = ops->stream_id(config, buf, &si);
1672                 if (ret < 0)
1673                         goto error;
1674                 return put_u64(si, arg);
1675         }
1676         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1677         {
1678                 uint64_t ts;
1679
1680                 ret = ops->current_timestamp(config, buf, &ts);
1681                 if (ret < 0)
1682                         goto error;
1683                 return put_u64(ts, arg);
1684         }
1685         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1686         {
1687                 uint64_t seq;
1688
1689                 ret = ops->sequence_number(config, buf, &seq);
1690                 if (ret < 0)
1691                         goto error;
1692                 return put_u64(seq, arg);
1693         }
1694         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1695         {
1696                 uint64_t id;
1697
1698                 ret = ops->instance_id(config, buf, &id);
1699                 if (ret < 0)
1700                         goto error;
1701                 return put_u64(id, arg);
1702         }
1703         default:
1704                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1705                                 cmd, arg);
1706         }
1707
1708 error:
1709         return -ENOSYS;
1710 }
1711 #endif /* CONFIG_COMPAT */
1712
1713 static void lttng_stream_override_ring_buffer_fops(void)
1714 {
1715         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1716         lttng_stream_ring_buffer_file_operations.open =
1717                 lib_ring_buffer_file_operations.open;
1718         lttng_stream_ring_buffer_file_operations.release =
1719                 lib_ring_buffer_file_operations.release;
1720         lttng_stream_ring_buffer_file_operations.poll =
1721                 lib_ring_buffer_file_operations.poll;
1722         lttng_stream_ring_buffer_file_operations.splice_read =
1723                 lib_ring_buffer_file_operations.splice_read;
1724         lttng_stream_ring_buffer_file_operations.mmap =
1725                 lib_ring_buffer_file_operations.mmap;
1726         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1727                 lttng_stream_ring_buffer_ioctl;
1728         lttng_stream_ring_buffer_file_operations.llseek =
1729                 lib_ring_buffer_file_operations.llseek;
1730 #ifdef CONFIG_COMPAT
1731         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1732                 lttng_stream_ring_buffer_compat_ioctl;
1733 #endif
1734 }
1735
1736 int __init lttng_abi_init(void)
1737 {
1738         int ret = 0;
1739
1740         wrapper_vmalloc_sync_all();
1741         lttng_clock_ref();
1742         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1743                                         &lttng_fops, NULL);
1744
1745         if (!lttng_proc_dentry) {
1746                 printk(KERN_ERR "Error creating LTTng control file\n");
1747                 ret = -ENOMEM;
1748                 goto error;
1749         }
1750         lttng_stream_override_ring_buffer_fops();
1751         return 0;
1752
1753 error:
1754         lttng_clock_unref();
1755         return ret;
1756 }
1757
1758 /* No __exit annotation because used by init error path too. */
1759 void lttng_abi_exit(void)
1760 {
1761         lttng_clock_unref();
1762         if (lttng_proc_dentry)
1763                 remove_proc_entry("lttng", NULL);
1764 }