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         case LTTNG_KERNEL_CONTEXT_CALLSTACK_KERNEL:
 251         case LTTNG_KERNEL_CONTEXT_CALLSTACK_USER:
 252                 return lttng_add_callstack_to_ctx(ctx, context_param->ctx);
 253         default:
 254                 return -EINVAL;
 255         }
 256 }
 257
 258 /**
 259  *      lttng_ioctl - lttng syscall through ioctl
 260  *
 261  *      @file: the file
 262  *      @cmd: the command
 263  *      @arg: command arg
 264  *
 265  *      This ioctl implements lttng commands:
 266  *      LTTNG_KERNEL_SESSION
 267  *              Returns a LTTng trace session file descriptor
 268  *      LTTNG_KERNEL_TRACER_VERSION
 269  *              Returns the LTTng kernel tracer version
 270  *      LTTNG_KERNEL_TRACEPOINT_LIST
 271  *              Returns a file descriptor listing available tracepoints
 272  *      LTTNG_KERNEL_WAIT_QUIESCENT
 273  *              Returns after all previously running probes have completed
 274  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 275  *              Returns the LTTng kernel tracer ABI version
 276  *
 277  * The returned session will be deleted when its file descriptor is closed.
 278  */
 279 static
 280 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 281 {
 282         switch (cmd) {
 283         case LTTNG_KERNEL_OLD_SESSION:
 284         case LTTNG_KERNEL_SESSION:
 285                 return lttng_abi_create_session();
 286         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 287         {
 288                 struct lttng_kernel_tracer_version v;
 289                 struct lttng_kernel_old_tracer_version oldv;
 290                 struct lttng_kernel_old_tracer_version *uversion =
 291                         (struct lttng_kernel_old_tracer_version __user *) arg;
 292
 293                 lttng_abi_tracer_version(&v);
 294                 oldv.major = v.major;
 295                 oldv.minor = v.minor;
 296                 oldv.patchlevel = v.patchlevel;
 297
 298                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 299                         return -EFAULT;
 300                 return 0;
 301         }
 302         case LTTNG_KERNEL_TRACER_VERSION:
 303         {
 304                 struct lttng_kernel_tracer_version version;
 305                 struct lttng_kernel_tracer_version *uversion =
 306                         (struct lttng_kernel_tracer_version __user *) arg;
 307
 308                 lttng_abi_tracer_version(&version);
 309
 310                 if (copy_to_user(uversion, &version, sizeof(version)))
 311                         return -EFAULT;
 312                 return 0;
 313         }
 314         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 315         {
 316                 struct lttng_kernel_tracer_abi_version version;
 317                 struct lttng_kernel_tracer_abi_version *uversion =
 318                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 319
 320                 lttng_abi_tracer_abi_version(&version);
 321
 322                 if (copy_to_user(uversion, &version, sizeof(version)))
 323                         return -EFAULT;
 324                 return 0;
 325         }
 326         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 327         case LTTNG_KERNEL_TRACEPOINT_LIST:
 328                 return lttng_abi_tracepoint_list();
 329         case LTTNG_KERNEL_SYSCALL_LIST:
 330                 return lttng_abi_syscall_list();
 331         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 332         case LTTNG_KERNEL_WAIT_QUIESCENT:
 333                 synchronize_trace();
 334                 return 0;
 335         case LTTNG_KERNEL_OLD_CALIBRATE:
 336         {
 337                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 338                         (struct lttng_kernel_old_calibrate __user *) arg;
 339                 struct lttng_kernel_old_calibrate old_calibrate;
 340                 struct lttng_kernel_calibrate calibrate;
 341                 int ret;
 342
 343                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 344                         return -EFAULT;
 345                 calibrate.type = old_calibrate.type;
 346                 ret = lttng_calibrate(&calibrate);
 347                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 348                         return -EFAULT;
 349                 return ret;
 350         }
 351         case LTTNG_KERNEL_CALIBRATE:
 352         {
 353                 struct lttng_kernel_calibrate __user *ucalibrate =
 354                         (struct lttng_kernel_calibrate __user *) arg;
 355                 struct lttng_kernel_calibrate calibrate;
 356                 int ret;
 357
 358                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 359                         return -EFAULT;
 360                 ret = lttng_calibrate(&calibrate);
 361                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 362                         return -EFAULT;
 363                 return ret;
 364         }
 365         default:
 366                 return -ENOIOCTLCMD;
 367         }
 368 }
 369
 370 static const struct file_operations lttng_fops = {
 371         .owner = THIS_MODULE,
 372         .unlocked_ioctl = lttng_ioctl,
 373 #ifdef CONFIG_COMPAT
 374         .compat_ioctl = lttng_ioctl,
 375 #endif
 376 };
 377
 378 static
 379 int lttng_abi_create_channel(struct file *session_file,
 380                              struct lttng_kernel_channel *chan_param,
 381                              enum channel_type channel_type)
 382 {
 383         struct lttng_session *session = session_file->private_data;
 384         const struct file_operations *fops = NULL;
 385         const char *transport_name;
 386         struct lttng_channel *chan;
 387         struct file *chan_file;
 388         int chan_fd;
 389         int ret = 0;
 390
 391         chan_fd = lttng_get_unused_fd();
 392         if (chan_fd < 0) {
 393                 ret = chan_fd;
 394                 goto fd_error;
 395         }
 396         switch (channel_type) {
 397         case PER_CPU_CHANNEL:
 398                 fops = &lttng_channel_fops;
 399                 break;
 400         case METADATA_CHANNEL:
 401                 fops = &lttng_metadata_fops;
 402                 break;
 403         }
 404
 405         chan_file = anon_inode_getfile("[lttng_channel]",
 406                                        fops,
 407                                        NULL, O_RDWR);
 408         if (IS_ERR(chan_file)) {
 409                 ret = PTR_ERR(chan_file);
 410                 goto file_error;
 411         }
 412         switch (channel_type) {
 413         case PER_CPU_CHANNEL:
 414                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 415                         transport_name = chan_param->overwrite ?
 416                                 "relay-overwrite" : "relay-discard";
 417                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 418                         transport_name = chan_param->overwrite ?
 419                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 420                 } else {
 421                         return -EINVAL;
 422                 }
 423                 break;
 424         case METADATA_CHANNEL:
 425                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 426                         transport_name = "relay-metadata";
 427                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 428                         transport_name = "relay-metadata-mmap";
 429                 else
 430                         return -EINVAL;
 431                 break;
 432         default:
 433                 transport_name = "<unknown>";
 434                 break;
 435         }
 436         if (atomic_long_add_unless(&session_file->f_count,
 437                 1, INT_MAX) == INT_MAX) {
 438                 goto refcount_error;
 439         }
 440         /*
 441          * We tolerate no failure path after channel creation. It will stay
 442          * invariant for the rest of the session.
 443          */
 444         chan = lttng_channel_create(session, transport_name, NULL,
 445                                   chan_param->subbuf_size,
 446                                   chan_param->num_subbuf,
 447                                   chan_param->switch_timer_interval,
 448                                   chan_param->read_timer_interval,
 449                                   channel_type);
 450         if (!chan) {
 451                 ret = -EINVAL;
 452                 goto chan_error;
 453         }
 454         chan->file = chan_file;
 455         chan_file->private_data = chan;
 456         fd_install(chan_fd, chan_file);
 457
 458         return chan_fd;
 459
 460 chan_error:
 461         atomic_long_dec(&session_file->f_count);
 462 refcount_error:
 463         fput(chan_file);
 464 file_error:
 465         put_unused_fd(chan_fd);
 466 fd_error:
 467         return ret;
 468 }
 469
 470 /**
 471  *      lttng_session_ioctl - lttng session fd ioctl
 472  *
 473  *      @file: the file
 474  *      @cmd: the command
 475  *      @arg: command arg
 476  *
 477  *      This ioctl implements lttng commands:
 478  *      LTTNG_KERNEL_CHANNEL
 479  *              Returns a LTTng channel file descriptor
 480  *      LTTNG_KERNEL_ENABLE
 481  *              Enables tracing for a session (weak enable)
 482  *      LTTNG_KERNEL_DISABLE
 483  *              Disables tracing for a session (strong disable)
 484  *      LTTNG_KERNEL_METADATA
 485  *              Returns a LTTng metadata file descriptor
 486  *      LTTNG_KERNEL_SESSION_TRACK_PID
 487  *              Add PID to session tracker
 488  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 489  *              Remove PID from session tracker
 490  *
 491  * The returned channel will be deleted when its file descriptor is closed.
 492  */
 493 static
 494 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 495 {
 496         struct lttng_session *session = file->private_data;
 497
 498         switch (cmd) {
 499         case LTTNG_KERNEL_OLD_CHANNEL:
 500         {
 501                 struct lttng_kernel_channel chan_param;
 502                 struct lttng_kernel_old_channel old_chan_param;
 503
 504                 if (copy_from_user(&old_chan_param,
 505                                 (struct lttng_kernel_old_channel __user *) arg,
 506                                 sizeof(struct lttng_kernel_old_channel)))
 507                         return -EFAULT;
 508                 chan_param.overwrite = old_chan_param.overwrite;
 509                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 510                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 511                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 512                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 513                 chan_param.output = old_chan_param.output;
 514
 515                 return lttng_abi_create_channel(file, &chan_param,
 516                                 PER_CPU_CHANNEL);
 517         }
 518         case LTTNG_KERNEL_CHANNEL:
 519         {
 520                 struct lttng_kernel_channel chan_param;
 521
 522                 if (copy_from_user(&chan_param,
 523                                 (struct lttng_kernel_channel __user *) arg,
 524                                 sizeof(struct lttng_kernel_channel)))
 525                         return -EFAULT;
 526                 return lttng_abi_create_channel(file, &chan_param,
 527                                 PER_CPU_CHANNEL);
 528         }
 529         case LTTNG_KERNEL_OLD_SESSION_START:
 530         case LTTNG_KERNEL_OLD_ENABLE:
 531         case LTTNG_KERNEL_SESSION_START:
 532         case LTTNG_KERNEL_ENABLE:
 533                 return lttng_session_enable(session);
 534         case LTTNG_KERNEL_OLD_SESSION_STOP:
 535         case LTTNG_KERNEL_OLD_DISABLE:
 536         case LTTNG_KERNEL_SESSION_STOP:
 537         case LTTNG_KERNEL_DISABLE:
 538                 return lttng_session_disable(session);
 539         case LTTNG_KERNEL_OLD_METADATA:
 540         {
 541                 struct lttng_kernel_channel chan_param;
 542                 struct lttng_kernel_old_channel old_chan_param;
 543
 544                 if (copy_from_user(&old_chan_param,
 545                                 (struct lttng_kernel_old_channel __user *) arg,
 546                                 sizeof(struct lttng_kernel_old_channel)))
 547                         return -EFAULT;
 548                 chan_param.overwrite = old_chan_param.overwrite;
 549                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 550                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 551                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 552                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 553                 chan_param.output = old_chan_param.output;
 554
 555                 return lttng_abi_create_channel(file, &chan_param,
 556                                 METADATA_CHANNEL);
 557         }
 558         case LTTNG_KERNEL_METADATA:
 559         {
 560                 struct lttng_kernel_channel chan_param;
 561
 562                 if (copy_from_user(&chan_param,
 563                                         (struct lttng_kernel_channel __user *) arg,
 564                                         sizeof(struct lttng_kernel_channel)))
 565                         return -EFAULT;
 566                 return lttng_abi_create_channel(file, &chan_param,
 567                                 METADATA_CHANNEL);
 568         }
 569         case LTTNG_KERNEL_SESSION_TRACK_PID:
 570                 return lttng_session_track_pid(session, (int) arg);
 571         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 572                 return lttng_session_untrack_pid(session, (int) arg);
 573         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 574                 return lttng_session_list_tracker_pids(session);
 575         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 576                 return lttng_session_metadata_regenerate(session);
 577         case LTTNG_KERNEL_SESSION_STATEDUMP:
 578                 return lttng_session_statedump(session);
 579         default:
 580                 return -ENOIOCTLCMD;
 581         }
 582 }
 583
 584 /*
 585  * Called when the last file reference is dropped.
 586  *
 587  * Big fat note: channels and events are invariant for the whole session after
 588  * their creation. So this session destruction also destroys all channel and
 589  * event structures specific to this session (they are not destroyed when their
 590  * individual file is released).
 591  */
 592 static
 593 int lttng_session_release(struct inode *inode, struct file *file)
 594 {
 595         struct lttng_session *session = file->private_data;
 596
 597         if (session)
 598                 lttng_session_destroy(session);
 599         return 0;
 600 }
 601
 602 static const struct file_operations lttng_session_fops = {
 603         .owner = THIS_MODULE,
 604         .release = lttng_session_release,
 605         .unlocked_ioctl = lttng_session_ioctl,
 606 #ifdef CONFIG_COMPAT
 607         .compat_ioctl = lttng_session_ioctl,
 608 #endif
 609 };
 610
 611 /**
 612  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 613  *      @filp: the file
 614  *      @wait: poll table
 615  *
 616  *      Handles the poll operations for the metadata channels.
 617  */
 618 static
 619 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 620                 poll_table *wait)
 621 {
 622         struct lttng_metadata_stream *stream = filp->private_data;
 623         struct lib_ring_buffer *buf = stream->priv;
 624         int finalized;
 625         unsigned int mask = 0;
 626
 627         if (filp->f_mode & FMODE_READ) {
 628                 poll_wait_set_exclusive(wait);
 629                 poll_wait(filp, &stream->read_wait, wait);
 630
 631                 finalized = stream->finalized;
 632
 633                 /*
 634                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 635                  * ordering finalized load before offsets loads.
 636                  */
 637                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 638
 639                 if (finalized)
 640                         mask |= POLLHUP;
 641
 642                 mutex_lock(&stream->metadata_cache->lock);
 643                 if (stream->metadata_cache->metadata_written >
 644                                 stream->metadata_out)
 645                         mask |= POLLIN;
 646                 mutex_unlock(&stream->metadata_cache->lock);
 647         }
 648
 649         return mask;
 650 }
 651
 652 static
 653 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 654                 unsigned int cmd, unsigned long arg)
 655 {
 656         struct lttng_metadata_stream *stream = filp->private_data;
 657
 658         stream->metadata_out = stream->metadata_in;
 659 }
 660
 661 /*
 662  * Reset the counter of how much metadata has been consumed to 0. That way,
 663  * the consumer receives the content of the metadata cache unchanged. This is
 664  * different from the metadata_regenerate where the offset from epoch is
 665  * resampled, here we want the exact same content as the last time the metadata
 666  * was generated. This command is only possible if all the metadata written
 667  * in the cache has been output to the metadata stream to avoid corrupting the
 668  * metadata file.
 669  *
 670  * Return 0 on success, a negative value on error.
 671  */
 672 static
 673 int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
 674 {
 675         int ret;
 676         struct lttng_metadata_cache *cache = stream->metadata_cache;
 677
 678         mutex_lock(&cache->lock);
 679         if (stream->metadata_out != cache->metadata_written) {
 680                 ret = -EBUSY;
 681                 goto end;
 682         }
 683         stream->metadata_out = 0;
 684         stream->metadata_in = 0;
 685         wake_up_interruptible(&stream->read_wait);
 686         ret = 0;
 687
 688 end:
 689         mutex_unlock(&cache->lock);
 690         return ret;
 691 }
 692
 693 static
 694 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 695                 unsigned int cmd, unsigned long arg)
 696 {
 697         int ret;
 698         struct lttng_metadata_stream *stream = filp->private_data;
 699         struct lib_ring_buffer *buf = stream->priv;
 700
 701         switch (cmd) {
 702         case RING_BUFFER_GET_NEXT_SUBBUF:
 703         {
 704                 struct lttng_metadata_stream *stream = filp->private_data;
 705                 struct lib_ring_buffer *buf = stream->priv;
 706                 struct channel *chan = buf->backend.chan;
 707
 708                 ret = lttng_metadata_output_channel(stream, chan);
 709                 if (ret > 0) {
 710                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 711                         ret = 0;
 712                 } else if (ret < 0)
 713                         goto err;
 714                 break;
 715         }
 716         case RING_BUFFER_GET_SUBBUF:
 717         {
 718                 /*
 719                  * Random access is not allowed for metadata channel.
 720                  */
 721                 return -ENOSYS;
 722         }
 723         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 724         case RING_BUFFER_FLUSH:
 725         {
 726                 struct lttng_metadata_stream *stream = filp->private_data;
 727                 struct lib_ring_buffer *buf = stream->priv;
 728                 struct channel *chan = buf->backend.chan;
 729
 730                 /*
 731                  * Before doing the actual ring buffer flush, write up to one
 732                  * packet of metadata in the ring buffer.
 733                  */
 734                 ret = lttng_metadata_output_channel(stream, chan);
 735                 if (ret < 0)
 736                         goto err;
 737                 break;
 738         }
 739         case RING_BUFFER_GET_METADATA_VERSION:
 740         {
 741                 struct lttng_metadata_stream *stream = filp->private_data;
 742
 743                 return put_u64(stream->version, arg);
 744         }
 745         case RING_BUFFER_METADATA_CACHE_DUMP:
 746         {
 747                 struct lttng_metadata_stream *stream = filp->private_data;
 748
 749                 return lttng_metadata_cache_dump(stream);
 750         }
 751         default:
 752                 break;
 753         }
 754         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 755
 756         /* Performing lib ring buffer ioctl after our own. */
 757         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 758         if (ret < 0)
 759                 goto err;
 760
 761         switch (cmd) {
 762         case RING_BUFFER_PUT_NEXT_SUBBUF:
 763         {
 764                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 765                                 cmd, arg);
 766                 break;
 767         }
 768         default:
 769                 break;
 770         }
 771 err:
 772         return ret;
 773 }
 774
 775 #ifdef CONFIG_COMPAT
 776 static
 777 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 778                 unsigned int cmd, unsigned long arg)
 779 {
 780         int ret;
 781         struct lttng_metadata_stream *stream = filp->private_data;
 782         struct lib_ring_buffer *buf = stream->priv;
 783
 784         switch (cmd) {
 785         case RING_BUFFER_GET_NEXT_SUBBUF:
 786         {
 787                 struct lttng_metadata_stream *stream = filp->private_data;
 788                 struct lib_ring_buffer *buf = stream->priv;
 789                 struct channel *chan = buf->backend.chan;
 790
 791                 ret = lttng_metadata_output_channel(stream, chan);
 792                 if (ret > 0) {
 793                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 794                         ret = 0;
 795                 } else if (ret < 0)
 796                         goto err;
 797                 break;
 798         }
 799         case RING_BUFFER_GET_SUBBUF:
 800         {
 801                 /*
 802                  * Random access is not allowed for metadata channel.
 803                  */
 804                 return -ENOSYS;
 805         }
 806         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 807         case RING_BUFFER_FLUSH:
 808         {
 809                 struct lttng_metadata_stream *stream = filp->private_data;
 810                 struct lib_ring_buffer *buf = stream->priv;
 811                 struct channel *chan = buf->backend.chan;
 812
 813                 /*
 814                  * Before doing the actual ring buffer flush, write up to one
 815                  * packet of metadata in the ring buffer.
 816                  */
 817                 ret = lttng_metadata_output_channel(stream, chan);
 818                 if (ret < 0)
 819                         goto err;
 820                 break;
 821         }
 822         case RING_BUFFER_GET_METADATA_VERSION:
 823         {
 824                 struct lttng_metadata_stream *stream = filp->private_data;
 825
 826                 return put_u64(stream->version, arg);
 827         }
 828         case RING_BUFFER_METADATA_CACHE_DUMP:
 829         {
 830                 struct lttng_metadata_stream *stream = filp->private_data;
 831
 832                 return lttng_metadata_cache_dump(stream);
 833         }
 834         default:
 835                 break;
 836         }
 837         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 838
 839         /* Performing lib ring buffer ioctl after our own. */
 840         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 841         if (ret < 0)
 842                 goto err;
 843
 844         switch (cmd) {
 845         case RING_BUFFER_PUT_NEXT_SUBBUF:
 846         {
 847                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 848                                 cmd, arg);
 849                 break;
 850         }
 851         default:
 852                 break;
 853         }
 854 err:
 855         return ret;
 856 }
 857 #endif
 858
 859 /*
 860  * This is not used by anonymous file descriptors. This code is left
 861  * there if we ever want to implement an inode with open() operation.
 862  */
 863 static
 864 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 865 {
 866         struct lttng_metadata_stream *stream = inode->i_private;
 867         struct lib_ring_buffer *buf = stream->priv;
 868
 869         file->private_data = buf;
 870         /*
 871          * Since life-time of metadata cache differs from that of
 872          * session, we need to keep our own reference on the transport.
 873          */
 874         if (!try_module_get(stream->transport->owner)) {
 875                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 876                 return -EBUSY;
 877         }
 878         return lib_ring_buffer_open(inode, file, buf);
 879 }
 880
 881 static
 882 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 883 {
 884         struct lttng_metadata_stream *stream = file->private_data;
 885         struct lib_ring_buffer *buf = stream->priv;
 886
 887         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 888         module_put(stream->transport->owner);
 889         return lib_ring_buffer_release(inode, file, buf);
 890 }
 891
 892 static
 893 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 894                 struct pipe_inode_info *pipe, size_t len,
 895                 unsigned int flags)
 896 {
 897         struct lttng_metadata_stream *stream = in->private_data;
 898         struct lib_ring_buffer *buf = stream->priv;
 899
 900         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 901                         flags, buf);
 902 }
 903
 904 static
 905 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 906                 struct vm_area_struct *vma)
 907 {
 908         struct lttng_metadata_stream *stream = filp->private_data;
 909         struct lib_ring_buffer *buf = stream->priv;
 910
 911         return lib_ring_buffer_mmap(filp, vma, buf);
 912 }
 913
 914 static
 915 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 916         .owner = THIS_MODULE,
 917         .open = lttng_metadata_ring_buffer_open,
 918         .release = lttng_metadata_ring_buffer_release,
 919         .poll = lttng_metadata_ring_buffer_poll,
 920         .splice_read = lttng_metadata_ring_buffer_splice_read,
 921         .mmap = lttng_metadata_ring_buffer_mmap,
 922         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 923         .llseek = vfs_lib_ring_buffer_no_llseek,
 924 #ifdef CONFIG_COMPAT
 925         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 926 #endif
 927 };
 928
 929 static
 930 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 931                 const struct file_operations *fops)
 932 {
 933         int stream_fd, ret;
 934         struct file *stream_file;
 935
 936         stream_fd = lttng_get_unused_fd();
 937         if (stream_fd < 0) {
 938                 ret = stream_fd;
 939                 goto fd_error;
 940         }
 941         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 942                         stream_priv, O_RDWR);
 943         if (IS_ERR(stream_file)) {
 944                 ret = PTR_ERR(stream_file);
 945                 goto file_error;
 946         }
 947         /*
 948          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 949          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 950          * file descriptor, so we set FMODE_PREAD here.
 951          */
 952         stream_file->f_mode |= FMODE_PREAD;
 953         fd_install(stream_fd, stream_file);
 954         /*
 955          * The stream holds a reference to the channel within the generic ring
 956          * buffer library, so no need to hold a refcount on the channel and
 957          * session files here.
 958          */
 959         return stream_fd;
 960
 961 file_error:
 962         put_unused_fd(stream_fd);
 963 fd_error:
 964         return ret;
 965 }
 966
 967 static
 968 int lttng_abi_open_stream(struct file *channel_file)
 969 {
 970         struct lttng_channel *channel = channel_file->private_data;
 971         struct lib_ring_buffer *buf;
 972         int ret;
 973         void *stream_priv;
 974
 975         buf = channel->ops->buffer_read_open(channel->chan);
 976         if (!buf)
 977                 return -ENOENT;
 978
 979         stream_priv = buf;
 980         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 981                         &lttng_stream_ring_buffer_file_operations);
 982         if (ret < 0)
 983                 goto fd_error;
 984
 985         return ret;
 986
 987 fd_error:
 988         channel->ops->buffer_read_close(buf);
 989         return ret;
 990 }
 991
 992 static
 993 int lttng_abi_open_metadata_stream(struct file *channel_file)
 994 {
 995         struct lttng_channel *channel = channel_file->private_data;
 996         struct lttng_session *session = channel->session;
 997         struct lib_ring_buffer *buf;
 998         int ret;
 999         struct lttng_metadata_stream *metadata_stream;
1000         void *stream_priv;
1001
1002         buf = channel->ops->buffer_read_open(channel->chan);
1003         if (!buf)
1004                 return -ENOENT;
1005
1006         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
1007                         GFP_KERNEL);
1008         if (!metadata_stream) {
1009                 ret = -ENOMEM;
1010                 goto nomem;
1011         }
1012         metadata_stream->metadata_cache = session->metadata_cache;
1013         init_waitqueue_head(&metadata_stream->read_wait);
1014         metadata_stream->priv = buf;
1015         stream_priv = metadata_stream;
1016         metadata_stream->transport = channel->transport;
1017
1018         /*
1019          * Since life-time of metadata cache differs from that of
1020          * session, we need to keep our own reference on the transport.
1021          */
1022         if (!try_module_get(metadata_stream->transport->owner)) {
1023                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
1024                 ret = -EINVAL;
1025                 goto notransport;
1026         }
1027
1028         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1029                 ret = -EOVERFLOW;
1030                 goto kref_error;
1031         }
1032
1033         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1034                         &lttng_metadata_ring_buffer_file_operations);
1035         if (ret < 0)
1036                 goto fd_error;
1037
1038         list_add(&metadata_stream->list,
1039                 &session->metadata_cache->metadata_stream);
1040         return ret;
1041
1042 fd_error:
1043         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1044 kref_error:
1045         module_put(metadata_stream->transport->owner);
1046 notransport:
1047         kfree(metadata_stream);
1048 nomem:
1049         channel->ops->buffer_read_close(buf);
1050         return ret;
1051 }
1052
1053 static
1054 int lttng_abi_create_event(struct file *channel_file,
1055                            struct lttng_kernel_event *event_param)
1056 {
1057         struct lttng_channel *channel = channel_file->private_data;
1058         int event_fd, ret;
1059         struct file *event_file;
1060         void *priv;
1061
1062         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1063         switch (event_param->instrumentation) {
1064         case LTTNG_KERNEL_KRETPROBE:
1065                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1066                 break;
1067         case LTTNG_KERNEL_KPROBE:
1068                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1069                 break;
1070         case LTTNG_KERNEL_FUNCTION:
1071                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1072                 break;
1073         default:
1074                 break;
1075         }
1076         event_fd = lttng_get_unused_fd();
1077         if (event_fd < 0) {
1078                 ret = event_fd;
1079                 goto fd_error;
1080         }
1081         event_file = anon_inode_getfile("[lttng_event]",
1082                                         &lttng_event_fops,
1083                                         NULL, O_RDWR);
1084         if (IS_ERR(event_file)) {
1085                 ret = PTR_ERR(event_file);
1086                 goto file_error;
1087         }
1088         /* The event holds a reference on the channel */
1089         if (atomic_long_add_unless(&channel_file->f_count,
1090                 1, INT_MAX) == INT_MAX) {
1091                 ret = -EOVERFLOW;
1092                 goto refcount_error;
1093         }
1094         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1095                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1096                 struct lttng_enabler *enabler;
1097
1098                 if (strutils_is_star_glob_pattern(event_param->name)) {
1099                         /*
1100                          * If the event name is a star globbing pattern,
1101                          * we create the special star globbing enabler.
1102                          */
1103                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1104                                 event_param, channel);
1105                 } else {
1106                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1107                                 event_param, channel);
1108                 }
1109                 priv = enabler;
1110         } else {
1111                 struct lttng_event *event;
1112
1113                 /*
1114                  * We tolerate no failure path after event creation. It
1115                  * will stay invariant for the rest of the session.
1116                  */
1117                 event = lttng_event_create(channel, event_param,
1118                                 NULL, NULL,
1119                                 event_param->instrumentation);
1120                 WARN_ON_ONCE(!event);
1121                 if (IS_ERR(event)) {
1122                         ret = PTR_ERR(event);
1123                         goto event_error;
1124                 }
1125                 priv = event;
1126         }
1127         event_file->private_data = priv;
1128         fd_install(event_fd, event_file);
1129         return event_fd;
1130
1131 event_error:
1132         atomic_long_dec(&channel_file->f_count);
1133 refcount_error:
1134         fput(event_file);
1135 file_error:
1136         put_unused_fd(event_fd);
1137 fd_error:
1138         return ret;
1139 }
1140
1141 /**
1142  *      lttng_channel_ioctl - lttng syscall through ioctl
1143  *
1144  *      @file: the file
1145  *      @cmd: the command
1146  *      @arg: command arg
1147  *
1148  *      This ioctl implements lttng commands:
1149  *      LTTNG_KERNEL_STREAM
1150  *              Returns an event stream file descriptor or failure.
1151  *              (typically, one event stream records events from one CPU)
1152  *      LTTNG_KERNEL_EVENT
1153  *              Returns an event file descriptor or failure.
1154  *      LTTNG_KERNEL_CONTEXT
1155  *              Prepend a context field to each event in the channel
1156  *      LTTNG_KERNEL_ENABLE
1157  *              Enable recording for events in this channel (weak enable)
1158  *      LTTNG_KERNEL_DISABLE
1159  *              Disable recording for events in this channel (strong disable)
1160  *
1161  * Channel and event file descriptors also hold a reference on the session.
1162  */
1163 static
1164 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1165 {
1166         struct lttng_channel *channel = file->private_data;
1167
1168         switch (cmd) {
1169         case LTTNG_KERNEL_OLD_STREAM:
1170         case LTTNG_KERNEL_STREAM:
1171                 return lttng_abi_open_stream(file);
1172         case LTTNG_KERNEL_OLD_EVENT:
1173         {
1174                 struct lttng_kernel_event *uevent_param;
1175                 struct lttng_kernel_old_event *old_uevent_param;
1176                 int ret;
1177
1178                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1179                                 GFP_KERNEL);
1180                 if (!uevent_param) {
1181                         ret = -ENOMEM;
1182                         goto old_event_end;
1183                 }
1184                 old_uevent_param = kmalloc(
1185                                 sizeof(struct lttng_kernel_old_event),
1186                                 GFP_KERNEL);
1187                 if (!old_uevent_param) {
1188                         ret = -ENOMEM;
1189                         goto old_event_error_free_param;
1190                 }
1191                 if (copy_from_user(old_uevent_param,
1192                                 (struct lttng_kernel_old_event __user *) arg,
1193                                 sizeof(struct lttng_kernel_old_event))) {
1194                         ret = -EFAULT;
1195                         goto old_event_error_free_old_param;
1196                 }
1197
1198                 memcpy(uevent_param->name, old_uevent_param->name,
1199                                 sizeof(uevent_param->name));
1200                 uevent_param->instrumentation =
1201                         old_uevent_param->instrumentation;
1202
1203                 switch (old_uevent_param->instrumentation) {
1204                 case LTTNG_KERNEL_KPROBE:
1205                         uevent_param->u.kprobe.addr =
1206                                 old_uevent_param->u.kprobe.addr;
1207                         uevent_param->u.kprobe.offset =
1208                                 old_uevent_param->u.kprobe.offset;
1209                         memcpy(uevent_param->u.kprobe.symbol_name,
1210                                 old_uevent_param->u.kprobe.symbol_name,
1211                                 sizeof(uevent_param->u.kprobe.symbol_name));
1212                         break;
1213                 case LTTNG_KERNEL_KRETPROBE:
1214                         uevent_param->u.kretprobe.addr =
1215                                 old_uevent_param->u.kretprobe.addr;
1216                         uevent_param->u.kretprobe.offset =
1217                                 old_uevent_param->u.kretprobe.offset;
1218                         memcpy(uevent_param->u.kretprobe.symbol_name,
1219                                 old_uevent_param->u.kretprobe.symbol_name,
1220                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1221                         break;
1222                 case LTTNG_KERNEL_FUNCTION:
1223                         memcpy(uevent_param->u.ftrace.symbol_name,
1224                                         old_uevent_param->u.ftrace.symbol_name,
1225                                         sizeof(uevent_param->u.ftrace.symbol_name));
1226                         break;
1227                 default:
1228                         break;
1229                 }
1230                 ret = lttng_abi_create_event(file, uevent_param);
1231
1232 old_event_error_free_old_param:
1233                 kfree(old_uevent_param);
1234 old_event_error_free_param:
1235                 kfree(uevent_param);
1236 old_event_end:
1237                 return ret;
1238         }
1239         case LTTNG_KERNEL_EVENT:
1240         {
1241                 struct lttng_kernel_event uevent_param;
1242
1243                 if (copy_from_user(&uevent_param,
1244                                 (struct lttng_kernel_event __user *) arg,
1245                                 sizeof(uevent_param)))
1246                         return -EFAULT;
1247                 return lttng_abi_create_event(file, &uevent_param);
1248         }
1249         case LTTNG_KERNEL_OLD_CONTEXT:
1250         {
1251                 struct lttng_kernel_context *ucontext_param;
1252                 struct lttng_kernel_old_context *old_ucontext_param;
1253                 int ret;
1254
1255                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1256                                 GFP_KERNEL);
1257                 if (!ucontext_param) {
1258                         ret = -ENOMEM;
1259                         goto old_ctx_end;
1260                 }
1261                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1262                                 GFP_KERNEL);
1263                 if (!old_ucontext_param) {
1264                         ret = -ENOMEM;
1265                         goto old_ctx_error_free_param;
1266                 }
1267
1268                 if (copy_from_user(old_ucontext_param,
1269                                 (struct lttng_kernel_old_context __user *) arg,
1270                                 sizeof(struct lttng_kernel_old_context))) {
1271                         ret = -EFAULT;
1272                         goto old_ctx_error_free_old_param;
1273                 }
1274                 ucontext_param->ctx = old_ucontext_param->ctx;
1275                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1276                                 sizeof(ucontext_param->padding));
1277                 /* only type that uses the union */
1278                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1279                         ucontext_param->u.perf_counter.type =
1280                                 old_ucontext_param->u.perf_counter.type;
1281                         ucontext_param->u.perf_counter.config =
1282                                 old_ucontext_param->u.perf_counter.config;
1283                         memcpy(ucontext_param->u.perf_counter.name,
1284                                 old_ucontext_param->u.perf_counter.name,
1285                                 sizeof(ucontext_param->u.perf_counter.name));
1286                 }
1287
1288                 ret = lttng_abi_add_context(file,
1289                                 ucontext_param,
1290                                 &channel->ctx, channel->session);
1291
1292 old_ctx_error_free_old_param:
1293                 kfree(old_ucontext_param);
1294 old_ctx_error_free_param:
1295                 kfree(ucontext_param);
1296 old_ctx_end:
1297                 return ret;
1298         }
1299         case LTTNG_KERNEL_CONTEXT:
1300         {
1301                 struct lttng_kernel_context ucontext_param;
1302
1303                 if (copy_from_user(&ucontext_param,
1304                                 (struct lttng_kernel_context __user *) arg,
1305                                 sizeof(ucontext_param)))
1306                         return -EFAULT;
1307                 return lttng_abi_add_context(file,
1308                                 &ucontext_param,
1309                                 &channel->ctx, channel->session);
1310         }
1311         case LTTNG_KERNEL_OLD_ENABLE:
1312         case LTTNG_KERNEL_ENABLE:
1313                 return lttng_channel_enable(channel);
1314         case LTTNG_KERNEL_OLD_DISABLE:
1315         case LTTNG_KERNEL_DISABLE:
1316                 return lttng_channel_disable(channel);
1317         case LTTNG_KERNEL_SYSCALL_MASK:
1318                 return lttng_channel_syscall_mask(channel,
1319                         (struct lttng_kernel_syscall_mask __user *) arg);
1320         default:
1321                 return -ENOIOCTLCMD;
1322         }
1323
1324 }
1325
1326 /**
1327  *      lttng_metadata_ioctl - lttng syscall through ioctl
1328  *
1329  *      @file: the file
1330  *      @cmd: the command
1331  *      @arg: command arg
1332  *
1333  *      This ioctl implements lttng commands:
1334  *      LTTNG_KERNEL_STREAM
1335  *              Returns an event stream file descriptor or failure.
1336  *
1337  * Channel and event file descriptors also hold a reference on the session.
1338  */
1339 static
1340 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1341 {
1342         switch (cmd) {
1343         case LTTNG_KERNEL_OLD_STREAM:
1344         case LTTNG_KERNEL_STREAM:
1345                 return lttng_abi_open_metadata_stream(file);
1346         default:
1347                 return -ENOIOCTLCMD;
1348         }
1349 }
1350
1351 /**
1352  *      lttng_channel_poll - lttng stream addition/removal monitoring
1353  *
1354  *      @file: the file
1355  *      @wait: poll table
1356  */
1357 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1358 {
1359         struct lttng_channel *channel = file->private_data;
1360         unsigned int mask = 0;
1361
1362         if (file->f_mode & FMODE_READ) {
1363                 poll_wait_set_exclusive(wait);
1364                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1365                           wait);
1366
1367                 if (channel->ops->is_disabled(channel->chan))
1368                         return POLLERR;
1369                 if (channel->ops->is_finalized(channel->chan))
1370                         return POLLHUP;
1371                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1372                         return POLLIN | POLLRDNORM;
1373                 return 0;
1374         }
1375         return mask;
1376
1377 }
1378
1379 static
1380 int lttng_channel_release(struct inode *inode, struct file *file)
1381 {
1382         struct lttng_channel *channel = file->private_data;
1383
1384         if (channel)
1385                 fput(channel->session->file);
1386         return 0;
1387 }
1388
1389 static
1390 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1391 {
1392         struct lttng_channel *channel = file->private_data;
1393
1394         if (channel) {
1395                 fput(channel->session->file);
1396                 lttng_metadata_channel_destroy(channel);
1397         }
1398
1399         return 0;
1400 }
1401
1402 static const struct file_operations lttng_channel_fops = {
1403         .owner = THIS_MODULE,
1404         .release = lttng_channel_release,
1405         .poll = lttng_channel_poll,
1406         .unlocked_ioctl = lttng_channel_ioctl,
1407 #ifdef CONFIG_COMPAT
1408         .compat_ioctl = lttng_channel_ioctl,
1409 #endif
1410 };
1411
1412 static const struct file_operations lttng_metadata_fops = {
1413         .owner = THIS_MODULE,
1414         .release = lttng_metadata_channel_release,
1415         .unlocked_ioctl = lttng_metadata_ioctl,
1416 #ifdef CONFIG_COMPAT
1417         .compat_ioctl = lttng_metadata_ioctl,
1418 #endif
1419 };
1420
1421 /**
1422  *      lttng_event_ioctl - lttng syscall through ioctl
1423  *
1424  *      @file: the file
1425  *      @cmd: the command
1426  *      @arg: command arg
1427  *
1428  *      This ioctl implements lttng commands:
1429  *      LTTNG_KERNEL_CONTEXT
1430  *              Prepend a context field to each record of this event
1431  *      LTTNG_KERNEL_ENABLE
1432  *              Enable recording for this event (weak enable)
1433  *      LTTNG_KERNEL_DISABLE
1434  *              Disable recording for this event (strong disable)
1435  */
1436 static
1437 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1438 {
1439         struct lttng_event *event;
1440         struct lttng_enabler *enabler;
1441         enum lttng_event_type *evtype = file->private_data;
1442
1443         switch (cmd) {
1444         case LTTNG_KERNEL_OLD_CONTEXT:
1445         {
1446                 /* Not implemented */
1447                 return -ENOSYS;
1448         }
1449         case LTTNG_KERNEL_CONTEXT:
1450         {
1451                 /* Not implemented */
1452                 return -ENOSYS;
1453         }
1454         case LTTNG_KERNEL_OLD_ENABLE:
1455         case LTTNG_KERNEL_ENABLE:
1456                 switch (*evtype) {
1457                 case LTTNG_TYPE_EVENT:
1458                         event = file->private_data;
1459                         return lttng_event_enable(event);
1460                 case LTTNG_TYPE_ENABLER:
1461                         enabler = file->private_data;
1462                         return lttng_enabler_enable(enabler);
1463                 default:
1464                         WARN_ON_ONCE(1);
1465                         return -ENOSYS;
1466                 }
1467         case LTTNG_KERNEL_OLD_DISABLE:
1468         case LTTNG_KERNEL_DISABLE:
1469                 switch (*evtype) {
1470                 case LTTNG_TYPE_EVENT:
1471                         event = file->private_data;
1472                         return lttng_event_disable(event);
1473                 case LTTNG_TYPE_ENABLER:
1474                         enabler = file->private_data;
1475                         return lttng_enabler_disable(enabler);
1476                 default:
1477                         WARN_ON_ONCE(1);
1478                         return -ENOSYS;
1479                 }
1480         case LTTNG_KERNEL_FILTER:
1481                 switch (*evtype) {
1482                 case LTTNG_TYPE_EVENT:
1483                         return -EINVAL;
1484                 case LTTNG_TYPE_ENABLER:
1485                 {
1486                         enabler = file->private_data;
1487                         return lttng_enabler_attach_bytecode(enabler,
1488                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1489                 }
1490
1491                 }
1492         default:
1493                 return -ENOIOCTLCMD;
1494         }
1495 }
1496
1497 static
1498 int lttng_event_release(struct inode *inode, struct file *file)
1499 {
1500         struct lttng_event *event;
1501         struct lttng_enabler *enabler;
1502         enum lttng_event_type *evtype = file->private_data;
1503
1504         if (!evtype)
1505                 return 0;
1506
1507         switch (*evtype) {
1508         case LTTNG_TYPE_EVENT:
1509                 event = file->private_data;
1510                 if (event)
1511                         fput(event->chan->file);
1512                 break;
1513         case LTTNG_TYPE_ENABLER:
1514                 enabler = file->private_data;
1515                 if (enabler)
1516                         fput(enabler->chan->file);
1517                 break;
1518         default:
1519                 WARN_ON_ONCE(1);
1520                 break;
1521         }
1522
1523         return 0;
1524 }
1525
1526 /* TODO: filter control ioctl */
1527 static const struct file_operations lttng_event_fops = {
1528         .owner = THIS_MODULE,
1529         .release = lttng_event_release,
1530         .unlocked_ioctl = lttng_event_ioctl,
1531 #ifdef CONFIG_COMPAT
1532         .compat_ioctl = lttng_event_ioctl,
1533 #endif
1534 };
1535
1536 static int put_u64(uint64_t val, unsigned long arg)
1537 {
1538         return put_user(val, (uint64_t __user *) arg);
1539 }
1540
1541 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1542                 unsigned int cmd, unsigned long arg)
1543 {
1544         struct lib_ring_buffer *buf = filp->private_data;
1545         struct channel *chan = buf->backend.chan;
1546         const struct lib_ring_buffer_config *config = &chan->backend.config;
1547         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1548         int ret;
1549
1550         if (atomic_read(&chan->record_disabled))
1551                 return -EIO;
1552
1553         switch (cmd) {
1554         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1555         {
1556                 uint64_t ts;
1557
1558                 ret = ops->timestamp_begin(config, buf, &ts);
1559                 if (ret < 0)
1560                         goto error;
1561                 return put_u64(ts, arg);
1562         }
1563         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1564         {
1565                 uint64_t ts;
1566
1567                 ret = ops->timestamp_end(config, buf, &ts);
1568                 if (ret < 0)
1569                         goto error;
1570                 return put_u64(ts, arg);
1571         }
1572         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1573         {
1574                 uint64_t ed;
1575
1576                 ret = ops->events_discarded(config, buf, &ed);
1577                 if (ret < 0)
1578                         goto error;
1579                 return put_u64(ed, arg);
1580         }
1581         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1582         {
1583                 uint64_t cs;
1584
1585                 ret = ops->content_size(config, buf, &cs);
1586                 if (ret < 0)
1587                         goto error;
1588                 return put_u64(cs, arg);
1589         }
1590         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1591         {
1592                 uint64_t ps;
1593
1594                 ret = ops->packet_size(config, buf, &ps);
1595                 if (ret < 0)
1596                         goto error;
1597                 return put_u64(ps, arg);
1598         }
1599         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1600         {
1601                 uint64_t si;
1602
1603                 ret = ops->stream_id(config, buf, &si);
1604                 if (ret < 0)
1605                         goto error;
1606                 return put_u64(si, arg);
1607         }
1608         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1609         {
1610                 uint64_t ts;
1611
1612                 ret = ops->current_timestamp(config, buf, &ts);
1613                 if (ret < 0)
1614                         goto error;
1615                 return put_u64(ts, arg);
1616         }
1617         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1618         {
1619                 uint64_t seq;
1620
1621                 ret = ops->sequence_number(config, buf, &seq);
1622                 if (ret < 0)
1623                         goto error;
1624                 return put_u64(seq, arg);
1625         }
1626         case LTTNG_RING_BUFFER_INSTANCE_ID:
1627         {
1628                 uint64_t id;
1629
1630                 ret = ops->instance_id(config, buf, &id);
1631                 if (ret < 0)
1632                         goto error;
1633                 return put_u64(id, arg);
1634         }
1635         default:
1636                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1637                                 cmd, arg);
1638         }
1639
1640 error:
1641         return -ENOSYS;
1642 }
1643
1644 #ifdef CONFIG_COMPAT
1645 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1646                 unsigned int cmd, unsigned long arg)
1647 {
1648         struct lib_ring_buffer *buf = filp->private_data;
1649         struct channel *chan = buf->backend.chan;
1650         const struct lib_ring_buffer_config *config = &chan->backend.config;
1651         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1652         int ret;
1653
1654         if (atomic_read(&chan->record_disabled))
1655                 return -EIO;
1656
1657         switch (cmd) {
1658         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1659         {
1660                 uint64_t ts;
1661
1662                 ret = ops->timestamp_begin(config, buf, &ts);
1663                 if (ret < 0)
1664                         goto error;
1665                 return put_u64(ts, arg);
1666         }
1667         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1668         {
1669                 uint64_t ts;
1670
1671                 ret = ops->timestamp_end(config, buf, &ts);
1672                 if (ret < 0)
1673                         goto error;
1674                 return put_u64(ts, arg);
1675         }
1676         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1677         {
1678                 uint64_t ed;
1679
1680                 ret = ops->events_discarded(config, buf, &ed);
1681                 if (ret < 0)
1682                         goto error;
1683                 return put_u64(ed, arg);
1684         }
1685         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1686         {
1687                 uint64_t cs;
1688
1689                 ret = ops->content_size(config, buf, &cs);
1690                 if (ret < 0)
1691                         goto error;
1692                 return put_u64(cs, arg);
1693         }
1694         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1695         {
1696                 uint64_t ps;
1697
1698                 ret = ops->packet_size(config, buf, &ps);
1699                 if (ret < 0)
1700                         goto error;
1701                 return put_u64(ps, arg);
1702         }
1703         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1704         {
1705                 uint64_t si;
1706
1707                 ret = ops->stream_id(config, buf, &si);
1708                 if (ret < 0)
1709                         goto error;
1710                 return put_u64(si, arg);
1711         }
1712         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1713         {
1714                 uint64_t ts;
1715
1716                 ret = ops->current_timestamp(config, buf, &ts);
1717                 if (ret < 0)
1718                         goto error;
1719                 return put_u64(ts, arg);
1720         }
1721         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1722         {
1723                 uint64_t seq;
1724
1725                 ret = ops->sequence_number(config, buf, &seq);
1726                 if (ret < 0)
1727                         goto error;
1728                 return put_u64(seq, arg);
1729         }
1730         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1731         {
1732                 uint64_t id;
1733
1734                 ret = ops->instance_id(config, buf, &id);
1735                 if (ret < 0)
1736                         goto error;
1737                 return put_u64(id, arg);
1738         }
1739         default:
1740                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1741                                 cmd, arg);
1742         }
1743
1744 error:
1745         return -ENOSYS;
1746 }
1747 #endif /* CONFIG_COMPAT */
1748
1749 static void lttng_stream_override_ring_buffer_fops(void)
1750 {
1751         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1752         lttng_stream_ring_buffer_file_operations.open =
1753                 lib_ring_buffer_file_operations.open;
1754         lttng_stream_ring_buffer_file_operations.release =
1755                 lib_ring_buffer_file_operations.release;
1756         lttng_stream_ring_buffer_file_operations.poll =
1757                 lib_ring_buffer_file_operations.poll;
1758         lttng_stream_ring_buffer_file_operations.splice_read =
1759                 lib_ring_buffer_file_operations.splice_read;
1760         lttng_stream_ring_buffer_file_operations.mmap =
1761                 lib_ring_buffer_file_operations.mmap;
1762         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1763                 lttng_stream_ring_buffer_ioctl;
1764         lttng_stream_ring_buffer_file_operations.llseek =
1765                 lib_ring_buffer_file_operations.llseek;
1766 #ifdef CONFIG_COMPAT
1767         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1768                 lttng_stream_ring_buffer_compat_ioctl;
1769 #endif
1770 }
1771
1772 int __init lttng_abi_init(void)
1773 {
1774         int ret = 0;
1775
1776         wrapper_vmalloc_sync_all();
1777         lttng_clock_ref();
1778
1779         ret = lttng_tp_mempool_init();
1780         if (ret) {
1781                 goto error;
1782         }
1783
1784         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1785                                         &lttng_fops, NULL);
1786
1787         if (!lttng_proc_dentry) {
1788                 printk(KERN_ERR "Error creating LTTng control file\n");
1789                 ret = -ENOMEM;
1790                 goto error;
1791         }
1792         lttng_stream_override_ring_buffer_fops();
1793         return 0;
1794
1795 error:
1796         lttng_tp_mempool_destroy();
1797         lttng_clock_unref();
1798         return ret;
1799 }
1800
1801 /* No __exit annotation because used by init error path too. */
1802 void lttng_abi_exit(void)
1803 {
1804         lttng_tp_mempool_destroy();
1805         lttng_clock_unref();
1806         if (lttng_proc_dentry)
1807                 remove_proc_entry("lttng", NULL);
1808 }