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