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