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