lttng-abi.c

   1 /*
   2  * lttng-abi.c
   3  *
   4  * LTTng ABI
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  *
  23  * Mimic system calls for:
  24  * - session creation, returns a file descriptor or failure.
  25  *   - channel creation, returns a file descriptor or failure.
  26  *     - Operates on a session file descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns a file descriptor or failure.
  29  *     - Operates on a channel file descriptor.
  30  *   - stream notifier get, returns a file descriptor or failure.
  31  *     - Operates on a channel file descriptor.
  32  *   - event creation, returns a file descriptor or failure.
  33  *     - Operates on a channel file descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/anon_inodes.h>
  43 #include <linux/file.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/slab.h>
  46 #include <linux/err.h>
  47 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  48 #include "wrapper/ringbuffer/vfs.h"
  49 #include "wrapper/ringbuffer/backend.h"
  50 #include "wrapper/ringbuffer/frontend.h"
  51 #include "wrapper/poll.h"
  52 #include "wrapper/file.h"
  53 #include "lttng-abi.h"
  54 #include "lttng-abi-old.h"
  55 #include "lttng-events.h"
  56 #include "lttng-tracer.h"
  57 #include "lib/ringbuffer/frontend_types.h"
  58
  59 /*
  60  * This is LTTng's own personal way to create a system call as an external
  61  * module. We use ioctl() on /proc/lttng.
  62  */
  63
  64 static struct proc_dir_entry *lttng_proc_dentry;
  65 static const struct file_operations lttng_fops;
  66 static const struct file_operations lttng_session_fops;
  67 static const struct file_operations lttng_channel_fops;
  68 static const struct file_operations lttng_metadata_fops;
  69 static const struct file_operations lttng_event_fops;
  70 static struct file_operations lttng_stream_ring_buffer_file_operations;
  71
  72 /*
  73  * Teardown management: opened file descriptors keep a refcount on the module,
  74  * so it can only exit when all file descriptors are closed.
  75  */
  76
  77 static
  78 int lttng_abi_create_session(void)
  79 {
  80         struct lttng_session *session;
  81         struct file *session_file;
  82         int session_fd, ret;
  83
  84         session = lttng_session_create();
  85         if (!session)
  86                 return -ENOMEM;
  87         session_fd = lttng_get_unused_fd();
  88         if (session_fd < 0) {
  89                 ret = session_fd;
  90                 goto fd_error;
  91         }
  92         session_file = anon_inode_getfile("[lttng_session]",
  93                                           &lttng_session_fops,
  94                                           session, O_RDWR);
  95         if (IS_ERR(session_file)) {
  96                 ret = PTR_ERR(session_file);
  97                 goto file_error;
  98         }
  99         session->file = session_file;
 100         fd_install(session_fd, session_file);
 101         return session_fd;
 102
 103 file_error:
 104         put_unused_fd(session_fd);
 105 fd_error:
 106         lttng_session_destroy(session);
 107         return ret;
 108 }
 109
 110 static
 111 int lttng_abi_tracepoint_list(void)
 112 {
 113         struct file *tracepoint_list_file;
 114         int file_fd, ret;
 115
 116         file_fd = lttng_get_unused_fd();
 117         if (file_fd < 0) {
 118                 ret = file_fd;
 119                 goto fd_error;
 120         }
 121
 122         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 123                                           &lttng_tracepoint_list_fops,
 124                                           NULL, O_RDWR);
 125         if (IS_ERR(tracepoint_list_file)) {
 126                 ret = PTR_ERR(tracepoint_list_file);
 127                 goto file_error;
 128         }
 129         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 130         if (ret < 0)
 131                 goto open_error;
 132         fd_install(file_fd, tracepoint_list_file);
 133         if (file_fd < 0) {
 134                 ret = file_fd;
 135                 goto fd_error;
 136         }
 137         return file_fd;
 138
 139 open_error:
 140         fput(tracepoint_list_file);
 141 file_error:
 142         put_unused_fd(file_fd);
 143 fd_error:
 144         return ret;
 145 }
 146
 147 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 148 static inline
 149 int lttng_abi_syscall_list(void)
 150 {
 151         return -ENOSYS;
 152 }
 153 #else
 154 static
 155 int lttng_abi_syscall_list(void)
 156 {
 157         struct file *syscall_list_file;
 158         int file_fd, ret;
 159
 160         file_fd = lttng_get_unused_fd();
 161         if (file_fd < 0) {
 162                 ret = file_fd;
 163                 goto fd_error;
 164         }
 165
 166         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 167                                           &lttng_syscall_list_fops,
 168                                           NULL, O_RDWR);
 169         if (IS_ERR(syscall_list_file)) {
 170                 ret = PTR_ERR(syscall_list_file);
 171                 goto file_error;
 172         }
 173         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 174         if (ret < 0)
 175                 goto open_error;
 176         fd_install(file_fd, syscall_list_file);
 177         if (file_fd < 0) {
 178                 ret = file_fd;
 179                 goto fd_error;
 180         }
 181         return file_fd;
 182
 183 open_error:
 184         fput(syscall_list_file);
 185 file_error:
 186         put_unused_fd(file_fd);
 187 fd_error:
 188         return ret;
 189 }
 190 #endif
 191
 192 static
 193 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 194 {
 195         v->major = LTTNG_MODULES_MAJOR_VERSION;
 196         v->minor = LTTNG_MODULES_MINOR_VERSION;
 197         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 198 }
 199
 200 static
 201 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 202 {
 203         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 204         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 205 }
 206
 207 static
 208 long lttng_abi_add_context(struct file *file,
 209         struct lttng_kernel_context *context_param,
 210         struct lttng_ctx **ctx, struct lttng_session *session)
 211 {
 212
 213         if (session->been_active)
 214                 return -EPERM;
 215
 216         switch (context_param->ctx) {
 217         case LTTNG_KERNEL_CONTEXT_PID:
 218                 return lttng_add_pid_to_ctx(ctx);
 219         case LTTNG_KERNEL_CONTEXT_PRIO:
 220                 return lttng_add_prio_to_ctx(ctx);
 221         case LTTNG_KERNEL_CONTEXT_NICE:
 222                 return lttng_add_nice_to_ctx(ctx);
 223         case LTTNG_KERNEL_CONTEXT_VPID:
 224                 return lttng_add_vpid_to_ctx(ctx);
 225         case LTTNG_KERNEL_CONTEXT_TID:
 226                 return lttng_add_tid_to_ctx(ctx);
 227         case LTTNG_KERNEL_CONTEXT_VTID:
 228                 return lttng_add_vtid_to_ctx(ctx);
 229         case LTTNG_KERNEL_CONTEXT_PPID:
 230                 return lttng_add_ppid_to_ctx(ctx);
 231         case LTTNG_KERNEL_CONTEXT_VPPID:
 232                 return lttng_add_vppid_to_ctx(ctx);
 233         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 234                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 235                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 236                                 context_param->u.perf_counter.config,
 237                                 context_param->u.perf_counter.name,
 238                                 ctx);
 239         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 240                 return lttng_add_procname_to_ctx(ctx);
 241         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 242                 return lttng_add_hostname_to_ctx(ctx);
 243         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 244                 return lttng_add_cpu_id_to_ctx(ctx);
 245         default:
 246                 return -EINVAL;
 247         }
 248 }
 249
 250 /**
 251  *      lttng_ioctl - lttng syscall through ioctl
 252  *
 253  *      @file: the file
 254  *      @cmd: the command
 255  *      @arg: command arg
 256  *
 257  *      This ioctl implements lttng commands:
 258  *      LTTNG_KERNEL_SESSION
 259  *              Returns a LTTng trace session file descriptor
 260  *      LTTNG_KERNEL_TRACER_VERSION
 261  *              Returns the LTTng kernel tracer version
 262  *      LTTNG_KERNEL_TRACEPOINT_LIST
 263  *              Returns a file descriptor listing available tracepoints
 264  *      LTTNG_KERNEL_WAIT_QUIESCENT
 265  *              Returns after all previously running probes have completed
 266  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 267  *              Returns the LTTng kernel tracer ABI version
 268  *
 269  * The returned session will be deleted when its file descriptor is closed.
 270  */
 271 static
 272 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 273 {
 274         switch (cmd) {
 275         case LTTNG_KERNEL_OLD_SESSION:
 276         case LTTNG_KERNEL_SESSION:
 277                 return lttng_abi_create_session();
 278         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 279         {
 280                 struct lttng_kernel_tracer_version v;
 281                 struct lttng_kernel_old_tracer_version oldv;
 282                 struct lttng_kernel_old_tracer_version *uversion =
 283                         (struct lttng_kernel_old_tracer_version __user *) arg;
 284
 285                 lttng_abi_tracer_version(&v);
 286                 oldv.major = v.major;
 287                 oldv.minor = v.minor;
 288                 oldv.patchlevel = v.patchlevel;
 289
 290                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 291                         return -EFAULT;
 292                 return 0;
 293         }
 294         case LTTNG_KERNEL_TRACER_VERSION:
 295         {
 296                 struct lttng_kernel_tracer_version version;
 297                 struct lttng_kernel_tracer_version *uversion =
 298                         (struct lttng_kernel_tracer_version __user *) arg;
 299
 300                 lttng_abi_tracer_version(&version);
 301
 302                 if (copy_to_user(uversion, &version, sizeof(version)))
 303                         return -EFAULT;
 304                 return 0;
 305         }
 306         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 307         {
 308                 struct lttng_kernel_tracer_abi_version version;
 309                 struct lttng_kernel_tracer_abi_version *uversion =
 310                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 311
 312                 lttng_abi_tracer_abi_version(&version);
 313
 314                 if (copy_to_user(uversion, &version, sizeof(version)))
 315                         return -EFAULT;
 316                 return 0;
 317         }
 318         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 319         case LTTNG_KERNEL_TRACEPOINT_LIST:
 320                 return lttng_abi_tracepoint_list();
 321         case LTTNG_KERNEL_SYSCALL_LIST:
 322                 return lttng_abi_syscall_list();
 323         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 324         case LTTNG_KERNEL_WAIT_QUIESCENT:
 325                 synchronize_trace();
 326                 return 0;
 327         case LTTNG_KERNEL_OLD_CALIBRATE:
 328         {
 329                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 330                         (struct lttng_kernel_old_calibrate __user *) arg;
 331                 struct lttng_kernel_old_calibrate old_calibrate;
 332                 struct lttng_kernel_calibrate calibrate;
 333                 int ret;
 334
 335                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 336                         return -EFAULT;
 337                 calibrate.type = old_calibrate.type;
 338                 ret = lttng_calibrate(&calibrate);
 339                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 340                         return -EFAULT;
 341                 return ret;
 342         }
 343         case LTTNG_KERNEL_CALIBRATE:
 344         {
 345                 struct lttng_kernel_calibrate __user *ucalibrate =
 346                         (struct lttng_kernel_calibrate __user *) arg;
 347                 struct lttng_kernel_calibrate calibrate;
 348                 int ret;
 349
 350                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 351                         return -EFAULT;
 352                 ret = lttng_calibrate(&calibrate);
 353                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 354                         return -EFAULT;
 355                 return ret;
 356         }
 357         default:
 358                 return -ENOIOCTLCMD;
 359         }
 360 }
 361
 362 static const struct file_operations lttng_fops = {
 363         .owner = THIS_MODULE,
 364         .unlocked_ioctl = lttng_ioctl,
 365 #ifdef CONFIG_COMPAT
 366         .compat_ioctl = lttng_ioctl,
 367 #endif
 368 };
 369
 370 static
 371 int lttng_abi_create_channel(struct file *session_file,
 372                              struct lttng_kernel_channel *chan_param,
 373                              enum channel_type channel_type)
 374 {
 375         struct lttng_session *session = session_file->private_data;
 376         const struct file_operations *fops = NULL;
 377         const char *transport_name;
 378         struct lttng_channel *chan;
 379         struct file *chan_file;
 380         int chan_fd;
 381         int ret = 0;
 382
 383         chan_fd = lttng_get_unused_fd();
 384         if (chan_fd < 0) {
 385                 ret = chan_fd;
 386                 goto fd_error;
 387         }
 388         switch (channel_type) {
 389         case PER_CPU_CHANNEL:
 390                 fops = &lttng_channel_fops;
 391                 break;
 392         case METADATA_CHANNEL:
 393                 fops = &lttng_metadata_fops;
 394                 break;
 395         }
 396
 397         chan_file = anon_inode_getfile("[lttng_channel]",
 398                                        fops,
 399                                        NULL, O_RDWR);
 400         if (IS_ERR(chan_file)) {
 401                 ret = PTR_ERR(chan_file);
 402                 goto file_error;
 403         }
 404         switch (channel_type) {
 405         case PER_CPU_CHANNEL:
 406                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 407                         transport_name = chan_param->overwrite ?
 408                                 "relay-overwrite" : "relay-discard";
 409                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 410                         transport_name = chan_param->overwrite ?
 411                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 412                 } else {
 413                         return -EINVAL;
 414                 }
 415                 break;
 416         case METADATA_CHANNEL:
 417                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 418                         transport_name = "relay-metadata";
 419                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 420                         transport_name = "relay-metadata-mmap";
 421                 else
 422                         return -EINVAL;
 423                 break;
 424         default:
 425                 transport_name = "<unknown>";
 426                 break;
 427         }
 428         /*
 429          * We tolerate no failure path after channel creation. It will stay
 430          * invariant for the rest of the session.
 431          */
 432         chan = lttng_channel_create(session, transport_name, NULL,
 433                                   chan_param->subbuf_size,
 434                                   chan_param->num_subbuf,
 435                                   chan_param->switch_timer_interval,
 436                                   chan_param->read_timer_interval,
 437                                   channel_type);
 438         if (!chan) {
 439                 ret = -EINVAL;
 440                 goto chan_error;
 441         }
 442         chan->file = chan_file;
 443         chan_file->private_data = chan;
 444         fd_install(chan_fd, chan_file);
 445         atomic_long_inc(&session_file->f_count);
 446
 447         return chan_fd;
 448
 449 chan_error:
 450         fput(chan_file);
 451 file_error:
 452         put_unused_fd(chan_fd);
 453 fd_error:
 454         return ret;
 455 }
 456
 457 /**
 458  *      lttng_session_ioctl - lttng session fd ioctl
 459  *
 460  *      @file: the file
 461  *      @cmd: the command
 462  *      @arg: command arg
 463  *
 464  *      This ioctl implements lttng commands:
 465  *      LTTNG_KERNEL_CHANNEL
 466  *              Returns a LTTng channel file descriptor
 467  *      LTTNG_KERNEL_ENABLE
 468  *              Enables tracing for a session (weak enable)
 469  *      LTTNG_KERNEL_DISABLE
 470  *              Disables tracing for a session (strong disable)
 471  *      LTTNG_KERNEL_METADATA
 472  *              Returns a LTTng metadata file descriptor
 473  *      LTTNG_KERNEL_SESSION_TRACK_PID
 474  *              Add PID to session tracker
 475  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 476  *              Remove PID from session tracker
 477  *
 478  * The returned channel will be deleted when its file descriptor is closed.
 479  */
 480 static
 481 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 482 {
 483         struct lttng_session *session = file->private_data;
 484
 485         switch (cmd) {
 486         case LTTNG_KERNEL_OLD_CHANNEL:
 487         {
 488                 struct lttng_kernel_channel chan_param;
 489                 struct lttng_kernel_old_channel old_chan_param;
 490
 491                 if (copy_from_user(&old_chan_param,
 492                                 (struct lttng_kernel_old_channel __user *) arg,
 493                                 sizeof(struct lttng_kernel_old_channel)))
 494                         return -EFAULT;
 495                 chan_param.overwrite = old_chan_param.overwrite;
 496                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 497                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 498                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 499                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 500                 chan_param.output = old_chan_param.output;
 501
 502                 return lttng_abi_create_channel(file, &chan_param,
 503                                 PER_CPU_CHANNEL);
 504         }
 505         case LTTNG_KERNEL_CHANNEL:
 506         {
 507                 struct lttng_kernel_channel chan_param;
 508
 509                 if (copy_from_user(&chan_param,
 510                                 (struct lttng_kernel_channel __user *) arg,
 511                                 sizeof(struct lttng_kernel_channel)))
 512                         return -EFAULT;
 513                 return lttng_abi_create_channel(file, &chan_param,
 514                                 PER_CPU_CHANNEL);
 515         }
 516         case LTTNG_KERNEL_OLD_SESSION_START:
 517         case LTTNG_KERNEL_OLD_ENABLE:
 518         case LTTNG_KERNEL_SESSION_START:
 519         case LTTNG_KERNEL_ENABLE:
 520                 return lttng_session_enable(session);
 521         case LTTNG_KERNEL_OLD_SESSION_STOP:
 522         case LTTNG_KERNEL_OLD_DISABLE:
 523         case LTTNG_KERNEL_SESSION_STOP:
 524         case LTTNG_KERNEL_DISABLE:
 525                 return lttng_session_disable(session);
 526         case LTTNG_KERNEL_OLD_METADATA:
 527         {
 528                 struct lttng_kernel_channel chan_param;
 529                 struct lttng_kernel_old_channel old_chan_param;
 530
 531                 if (copy_from_user(&old_chan_param,
 532                                 (struct lttng_kernel_old_channel __user *) arg,
 533                                 sizeof(struct lttng_kernel_old_channel)))
 534                         return -EFAULT;
 535                 chan_param.overwrite = old_chan_param.overwrite;
 536                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 537                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 538                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 539                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 540                 chan_param.output = old_chan_param.output;
 541
 542                 return lttng_abi_create_channel(file, &chan_param,
 543                                 METADATA_CHANNEL);
 544         }
 545         case LTTNG_KERNEL_METADATA:
 546         {
 547                 struct lttng_kernel_channel chan_param;
 548
 549                 if (copy_from_user(&chan_param,
 550                                         (struct lttng_kernel_channel __user *) arg,
 551                                         sizeof(struct lttng_kernel_channel)))
 552                         return -EFAULT;
 553                 return lttng_abi_create_channel(file, &chan_param,
 554                                 METADATA_CHANNEL);
 555         }
 556         case LTTNG_KERNEL_SESSION_TRACK_PID:
 557                 return lttng_session_track_pid(session, (int) arg);
 558         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 559                 return lttng_session_untrack_pid(session, (int) arg);
 560         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 561                 return lttng_session_list_tracker_pids(session);
 562         default:
 563                 return -ENOIOCTLCMD;
 564         }
 565 }
 566
 567 /*
 568  * Called when the last file reference is dropped.
 569  *
 570  * Big fat note: channels and events are invariant for the whole session after
 571  * their creation. So this session destruction also destroys all channel and
 572  * event structures specific to this session (they are not destroyed when their
 573  * individual file is released).
 574  */
 575 static
 576 int lttng_session_release(struct inode *inode, struct file *file)
 577 {
 578         struct lttng_session *session = file->private_data;
 579
 580         if (session)
 581                 lttng_session_destroy(session);
 582         return 0;
 583 }
 584
 585 static const struct file_operations lttng_session_fops = {
 586         .owner = THIS_MODULE,
 587         .release = lttng_session_release,
 588         .unlocked_ioctl = lttng_session_ioctl,
 589 #ifdef CONFIG_COMPAT
 590         .compat_ioctl = lttng_session_ioctl,
 591 #endif
 592 };
 593
 594 /**
 595  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 596  *      @filp: the file
 597  *      @wait: poll table
 598  *
 599  *      Handles the poll operations for the metadata channels.
 600  */
 601 static
 602 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 603                 poll_table *wait)
 604 {
 605         struct lttng_metadata_stream *stream = filp->private_data;
 606         struct lib_ring_buffer *buf = stream->priv;
 607         int finalized;
 608         unsigned int mask = 0;
 609
 610         if (filp->f_mode & FMODE_READ) {
 611                 poll_wait_set_exclusive(wait);
 612                 poll_wait(filp, &stream->read_wait, wait);
 613
 614                 finalized = stream->finalized;
 615
 616                 /*
 617                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 618                  * ordering finalized load before offsets loads.
 619                  */
 620                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 621
 622                 if (finalized)
 623                         mask |= POLLHUP;
 624
 625                 if (stream->metadata_cache->metadata_written >
 626                                 stream->metadata_out)
 627                         mask |= POLLIN;
 628         }
 629
 630         return mask;
 631 }
 632
 633 static
 634 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 635                 unsigned int cmd, unsigned long arg)
 636 {
 637         struct lttng_metadata_stream *stream = filp->private_data;
 638
 639         stream->metadata_out = stream->metadata_in;
 640 }
 641
 642 static
 643 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 644                 unsigned int cmd, unsigned long arg)
 645 {
 646         int ret;
 647         struct lttng_metadata_stream *stream = filp->private_data;
 648         struct lib_ring_buffer *buf = stream->priv;
 649
 650         switch (cmd) {
 651         case RING_BUFFER_GET_NEXT_SUBBUF:
 652         {
 653                 struct lttng_metadata_stream *stream = filp->private_data;
 654                 struct lib_ring_buffer *buf = stream->priv;
 655                 struct channel *chan = buf->backend.chan;
 656
 657                 ret = lttng_metadata_output_channel(stream, chan);
 658                 if (ret > 0) {
 659                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 660                         ret = 0;
 661                 } else if (ret < 0)
 662                         goto err;
 663                 break;
 664         }
 665         case RING_BUFFER_GET_SUBBUF:
 666         {
 667                 /*
 668                  * Random access is not allowed for metadata channel.
 669                  */
 670                 return -ENOSYS;
 671         }
 672         case RING_BUFFER_FLUSH:
 673         {
 674                 struct lttng_metadata_stream *stream = filp->private_data;
 675                 struct lib_ring_buffer *buf = stream->priv;
 676                 struct channel *chan = buf->backend.chan;
 677
 678                 /*
 679                  * Before doing the actual ring buffer flush, write up to one
 680                  * packet of metadata in the ring buffer.
 681                  */
 682                 ret = lttng_metadata_output_channel(stream, chan);
 683                 if (ret < 0)
 684                         goto err;
 685                 break;
 686         }
 687         default:
 688                 break;
 689         }
 690         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 691
 692         /* Performing lib ring buffer ioctl after our own. */
 693         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 694         if (ret < 0)
 695                 goto err;
 696
 697         switch (cmd) {
 698         case RING_BUFFER_PUT_NEXT_SUBBUF:
 699         {
 700                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 701                                 cmd, arg);
 702                 break;
 703         }
 704         default:
 705                 break;
 706         }
 707 err:
 708         return ret;
 709 }
 710
 711 #ifdef CONFIG_COMPAT
 712 static
 713 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 714                 unsigned int cmd, unsigned long arg)
 715 {
 716         int ret;
 717         struct lttng_metadata_stream *stream = filp->private_data;
 718         struct lib_ring_buffer *buf = stream->priv;
 719
 720         switch (cmd) {
 721         case RING_BUFFER_GET_NEXT_SUBBUF:
 722         {
 723                 struct lttng_metadata_stream *stream = filp->private_data;
 724                 struct lib_ring_buffer *buf = stream->priv;
 725                 struct channel *chan = buf->backend.chan;
 726
 727                 ret = lttng_metadata_output_channel(stream, chan);
 728                 if (ret > 0) {
 729                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 730                         ret = 0;
 731                 } else if (ret < 0)
 732                         goto err;
 733                 break;
 734         }
 735         case RING_BUFFER_GET_SUBBUF:
 736         {
 737                 /*
 738                  * Random access is not allowed for metadata channel.
 739                  */
 740                 return -ENOSYS;
 741         }
 742         default:
 743                 break;
 744         }
 745         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 746
 747         /* Performing lib ring buffer ioctl after our own. */
 748         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 749         if (ret < 0)
 750                 goto err;
 751
 752         switch (cmd) {
 753         case RING_BUFFER_PUT_NEXT_SUBBUF:
 754         {
 755                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 756                                 cmd, arg);
 757                 break;
 758         }
 759         default:
 760                 break;
 761         }
 762 err:
 763         return ret;
 764 }
 765 #endif
 766
 767 /*
 768  * This is not used by anonymous file descriptors. This code is left
 769  * there if we ever want to implement an inode with open() operation.
 770  */
 771 static
 772 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 773 {
 774         struct lttng_metadata_stream *stream = inode->i_private;
 775         struct lib_ring_buffer *buf = stream->priv;
 776
 777         file->private_data = buf;
 778         /*
 779          * Since life-time of metadata cache differs from that of
 780          * session, we need to keep our own reference on the transport.
 781          */
 782         if (!try_module_get(stream->transport->owner)) {
 783                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 784                 return -EBUSY;
 785         }
 786         return lib_ring_buffer_open(inode, file, buf);
 787 }
 788
 789 static
 790 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 791 {
 792         struct lttng_metadata_stream *stream = file->private_data;
 793         struct lib_ring_buffer *buf = stream->priv;
 794
 795         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 796         module_put(stream->transport->owner);
 797         return lib_ring_buffer_release(inode, file, buf);
 798 }
 799
 800 static
 801 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 802                 struct pipe_inode_info *pipe, size_t len,
 803                 unsigned int flags)
 804 {
 805         struct lttng_metadata_stream *stream = in->private_data;
 806         struct lib_ring_buffer *buf = stream->priv;
 807
 808         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 809                         flags, buf);
 810 }
 811
 812 static
 813 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 814                 struct vm_area_struct *vma)
 815 {
 816         struct lttng_metadata_stream *stream = filp->private_data;
 817         struct lib_ring_buffer *buf = stream->priv;
 818
 819         return lib_ring_buffer_mmap(filp, vma, buf);
 820 }
 821
 822 static
 823 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 824         .owner = THIS_MODULE,
 825         .open = lttng_metadata_ring_buffer_open,
 826         .release = lttng_metadata_ring_buffer_release,
 827         .poll = lttng_metadata_ring_buffer_poll,
 828         .splice_read = lttng_metadata_ring_buffer_splice_read,
 829         .mmap = lttng_metadata_ring_buffer_mmap,
 830         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 831         .llseek = vfs_lib_ring_buffer_no_llseek,
 832 #ifdef CONFIG_COMPAT
 833         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 834 #endif
 835 };
 836
 837 static
 838 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 839                 const struct file_operations *fops)
 840 {
 841         int stream_fd, ret;
 842         struct file *stream_file;
 843
 844         stream_fd = lttng_get_unused_fd();
 845         if (stream_fd < 0) {
 846                 ret = stream_fd;
 847                 goto fd_error;
 848         }
 849         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 850                         stream_priv, O_RDWR);
 851         if (IS_ERR(stream_file)) {
 852                 ret = PTR_ERR(stream_file);
 853                 goto file_error;
 854         }
 855         /*
 856          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 857          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 858          * file descriptor, so we set FMODE_PREAD here.
 859          */
 860         stream_file->f_mode |= FMODE_PREAD;
 861         fd_install(stream_fd, stream_file);
 862         /*
 863          * The stream holds a reference to the channel within the generic ring
 864          * buffer library, so no need to hold a refcount on the channel and
 865          * session files here.
 866          */
 867         return stream_fd;
 868
 869 file_error:
 870         put_unused_fd(stream_fd);
 871 fd_error:
 872         return ret;
 873 }
 874
 875 static
 876 int lttng_abi_open_stream(struct file *channel_file)
 877 {
 878         struct lttng_channel *channel = channel_file->private_data;
 879         struct lib_ring_buffer *buf;
 880         int ret;
 881         void *stream_priv;
 882
 883         buf = channel->ops->buffer_read_open(channel->chan);
 884         if (!buf)
 885                 return -ENOENT;
 886
 887         stream_priv = buf;
 888         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 889                         &lttng_stream_ring_buffer_file_operations);
 890         if (ret < 0)
 891                 goto fd_error;
 892
 893         return ret;
 894
 895 fd_error:
 896         channel->ops->buffer_read_close(buf);
 897         return ret;
 898 }
 899
 900 static
 901 int lttng_abi_open_metadata_stream(struct file *channel_file)
 902 {
 903         struct lttng_channel *channel = channel_file->private_data;
 904         struct lttng_session *session = channel->session;
 905         struct lib_ring_buffer *buf;
 906         int ret;
 907         struct lttng_metadata_stream *metadata_stream;
 908         void *stream_priv;
 909
 910         buf = channel->ops->buffer_read_open(channel->chan);
 911         if (!buf)
 912                 return -ENOENT;
 913
 914         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 915                         GFP_KERNEL);
 916         if (!metadata_stream) {
 917                 ret = -ENOMEM;
 918                 goto nomem;
 919         }
 920         metadata_stream->metadata_cache = session->metadata_cache;
 921         init_waitqueue_head(&metadata_stream->read_wait);
 922         metadata_stream->priv = buf;
 923         stream_priv = metadata_stream;
 924         metadata_stream->transport = channel->transport;
 925         mutex_init(&metadata_stream->lock);
 926
 927         /*
 928          * Since life-time of metadata cache differs from that of
 929          * session, we need to keep our own reference on the transport.
 930          */
 931         if (!try_module_get(metadata_stream->transport->owner)) {
 932                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 933                 ret = -EINVAL;
 934                 goto notransport;
 935         }
 936
 937         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 938                         &lttng_metadata_ring_buffer_file_operations);
 939         if (ret < 0)
 940                 goto fd_error;
 941
 942         kref_get(&session->metadata_cache->refcount);
 943         list_add(&metadata_stream->list,
 944                 &session->metadata_cache->metadata_stream);
 945         return ret;
 946
 947 fd_error:
 948         module_put(metadata_stream->transport->owner);
 949 notransport:
 950         kfree(metadata_stream);
 951 nomem:
 952         channel->ops->buffer_read_close(buf);
 953         return ret;
 954 }
 955
 956 static
 957 int lttng_abi_create_event(struct file *channel_file,
 958                            struct lttng_kernel_event *event_param)
 959 {
 960         struct lttng_channel *channel = channel_file->private_data;
 961         int event_fd, ret;
 962         struct file *event_file;
 963         void *priv;
 964
 965         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 966         switch (event_param->instrumentation) {
 967         case LTTNG_KERNEL_KRETPROBE:
 968                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 969                 break;
 970         case LTTNG_KERNEL_KPROBE:
 971                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 972                 break;
 973         case LTTNG_KERNEL_FUNCTION:
 974                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 975                 break;
 976         default:
 977                 break;
 978         }
 979         event_fd = lttng_get_unused_fd();
 980         if (event_fd < 0) {
 981                 ret = event_fd;
 982                 goto fd_error;
 983         }
 984         event_file = anon_inode_getfile("[lttng_event]",
 985                                         &lttng_event_fops,
 986                                         NULL, O_RDWR);
 987         if (IS_ERR(event_file)) {
 988                 ret = PTR_ERR(event_file);
 989                 goto file_error;
 990         }
 991         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
 992                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
 993                 struct lttng_enabler *enabler;
 994
 995                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
 996                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
 997                                 event_param, channel);
 998                 } else {
 999                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1000                                 event_param, channel);
1001                 }
1002                 priv = enabler;
1003         } else {
1004                 struct lttng_event *event;
1005
1006                 /*
1007                  * We tolerate no failure path after event creation. It
1008                  * will stay invariant for the rest of the session.
1009                  */
1010                 event = lttng_event_create(channel, event_param,
1011                                 NULL, NULL,
1012                                 event_param->instrumentation);
1013                 WARN_ON_ONCE(!event);
1014                 if (IS_ERR(event)) {
1015                         ret = PTR_ERR(event);
1016                         goto event_error;
1017                 }
1018                 priv = event;
1019         }
1020         event_file->private_data = priv;
1021         fd_install(event_fd, event_file);
1022         /* The event holds a reference on the channel */
1023         atomic_long_inc(&channel_file->f_count);
1024         return event_fd;
1025
1026 event_error:
1027         fput(event_file);
1028 file_error:
1029         put_unused_fd(event_fd);
1030 fd_error:
1031         return ret;
1032 }
1033
1034 /**
1035  *      lttng_channel_ioctl - lttng syscall through ioctl
1036  *
1037  *      @file: the file
1038  *      @cmd: the command
1039  *      @arg: command arg
1040  *
1041  *      This ioctl implements lttng commands:
1042  *      LTTNG_KERNEL_STREAM
1043  *              Returns an event stream file descriptor or failure.
1044  *              (typically, one event stream records events from one CPU)
1045  *      LTTNG_KERNEL_EVENT
1046  *              Returns an event file descriptor or failure.
1047  *      LTTNG_KERNEL_CONTEXT
1048  *              Prepend a context field to each event in the channel
1049  *      LTTNG_KERNEL_ENABLE
1050  *              Enable recording for events in this channel (weak enable)
1051  *      LTTNG_KERNEL_DISABLE
1052  *              Disable recording for events in this channel (strong disable)
1053  *
1054  * Channel and event file descriptors also hold a reference on the session.
1055  */
1056 static
1057 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1058 {
1059         struct lttng_channel *channel = file->private_data;
1060
1061         switch (cmd) {
1062         case LTTNG_KERNEL_OLD_STREAM:
1063         case LTTNG_KERNEL_STREAM:
1064                 return lttng_abi_open_stream(file);
1065         case LTTNG_KERNEL_OLD_EVENT:
1066         {
1067                 struct lttng_kernel_event *uevent_param;
1068                 struct lttng_kernel_old_event *old_uevent_param;
1069                 int ret;
1070
1071                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1072                                 GFP_KERNEL);
1073                 if (!uevent_param) {
1074                         ret = -ENOMEM;
1075                         goto old_event_end;
1076                 }
1077                 old_uevent_param = kmalloc(
1078                                 sizeof(struct lttng_kernel_old_event),
1079                                 GFP_KERNEL);
1080                 if (!old_uevent_param) {
1081                         ret = -ENOMEM;
1082                         goto old_event_error_free_param;
1083                 }
1084                 if (copy_from_user(old_uevent_param,
1085                                 (struct lttng_kernel_old_event __user *) arg,
1086                                 sizeof(struct lttng_kernel_old_event))) {
1087                         ret = -EFAULT;
1088                         goto old_event_error_free_old_param;
1089                 }
1090
1091                 memcpy(uevent_param->name, old_uevent_param->name,
1092                                 sizeof(uevent_param->name));
1093                 uevent_param->instrumentation =
1094                         old_uevent_param->instrumentation;
1095
1096                 switch (old_uevent_param->instrumentation) {
1097                 case LTTNG_KERNEL_KPROBE:
1098                         uevent_param->u.kprobe.addr =
1099                                 old_uevent_param->u.kprobe.addr;
1100                         uevent_param->u.kprobe.offset =
1101                                 old_uevent_param->u.kprobe.offset;
1102                         memcpy(uevent_param->u.kprobe.symbol_name,
1103                                 old_uevent_param->u.kprobe.symbol_name,
1104                                 sizeof(uevent_param->u.kprobe.symbol_name));
1105                         break;
1106                 case LTTNG_KERNEL_KRETPROBE:
1107                         uevent_param->u.kretprobe.addr =
1108                                 old_uevent_param->u.kretprobe.addr;
1109                         uevent_param->u.kretprobe.offset =
1110                                 old_uevent_param->u.kretprobe.offset;
1111                         memcpy(uevent_param->u.kretprobe.symbol_name,
1112                                 old_uevent_param->u.kretprobe.symbol_name,
1113                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1114                         break;
1115                 case LTTNG_KERNEL_FUNCTION:
1116                         memcpy(uevent_param->u.ftrace.symbol_name,
1117                                         old_uevent_param->u.ftrace.symbol_name,
1118                                         sizeof(uevent_param->u.ftrace.symbol_name));
1119                         break;
1120                 default:
1121                         break;
1122                 }
1123                 ret = lttng_abi_create_event(file, uevent_param);
1124
1125 old_event_error_free_old_param:
1126                 kfree(old_uevent_param);
1127 old_event_error_free_param:
1128                 kfree(uevent_param);
1129 old_event_end:
1130                 return ret;
1131         }
1132         case LTTNG_KERNEL_EVENT:
1133         {
1134                 struct lttng_kernel_event uevent_param;
1135
1136                 if (copy_from_user(&uevent_param,
1137                                 (struct lttng_kernel_event __user *) arg,
1138                                 sizeof(uevent_param)))
1139                         return -EFAULT;
1140                 return lttng_abi_create_event(file, &uevent_param);
1141         }
1142         case LTTNG_KERNEL_OLD_CONTEXT:
1143         {
1144                 struct lttng_kernel_context *ucontext_param;
1145                 struct lttng_kernel_old_context *old_ucontext_param;
1146                 int ret;
1147
1148                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1149                                 GFP_KERNEL);
1150                 if (!ucontext_param) {
1151                         ret = -ENOMEM;
1152                         goto old_ctx_end;
1153                 }
1154                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1155                                 GFP_KERNEL);
1156                 if (!old_ucontext_param) {
1157                         ret = -ENOMEM;
1158                         goto old_ctx_error_free_param;
1159                 }
1160
1161                 if (copy_from_user(old_ucontext_param,
1162                                 (struct lttng_kernel_old_context __user *) arg,
1163                                 sizeof(struct lttng_kernel_old_context))) {
1164                         ret = -EFAULT;
1165                         goto old_ctx_error_free_old_param;
1166                 }
1167                 ucontext_param->ctx = old_ucontext_param->ctx;
1168                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1169                                 sizeof(ucontext_param->padding));
1170                 /* only type that uses the union */
1171                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1172                         ucontext_param->u.perf_counter.type =
1173                                 old_ucontext_param->u.perf_counter.type;
1174                         ucontext_param->u.perf_counter.config =
1175                                 old_ucontext_param->u.perf_counter.config;
1176                         memcpy(ucontext_param->u.perf_counter.name,
1177                                 old_ucontext_param->u.perf_counter.name,
1178                                 sizeof(ucontext_param->u.perf_counter.name));
1179                 }
1180
1181                 ret = lttng_abi_add_context(file,
1182                                 ucontext_param,
1183                                 &channel->ctx, channel->session);
1184
1185 old_ctx_error_free_old_param:
1186                 kfree(old_ucontext_param);
1187 old_ctx_error_free_param:
1188                 kfree(ucontext_param);
1189 old_ctx_end:
1190                 return ret;
1191         }
1192         case LTTNG_KERNEL_CONTEXT:
1193         {
1194                 struct lttng_kernel_context ucontext_param;
1195
1196                 if (copy_from_user(&ucontext_param,
1197                                 (struct lttng_kernel_context __user *) arg,
1198                                 sizeof(ucontext_param)))
1199                         return -EFAULT;
1200                 return lttng_abi_add_context(file,
1201                                 &ucontext_param,
1202                                 &channel->ctx, channel->session);
1203         }
1204         case LTTNG_KERNEL_OLD_ENABLE:
1205         case LTTNG_KERNEL_ENABLE:
1206                 return lttng_channel_enable(channel);
1207         case LTTNG_KERNEL_OLD_DISABLE:
1208         case LTTNG_KERNEL_DISABLE:
1209                 return lttng_channel_disable(channel);
1210         case LTTNG_KERNEL_SYSCALL_MASK:
1211                 return lttng_channel_syscall_mask(channel,
1212                         (struct lttng_kernel_syscall_mask __user *) arg);
1213         default:
1214                 return -ENOIOCTLCMD;
1215         }
1216
1217 }
1218
1219 /**
1220  *      lttng_metadata_ioctl - lttng syscall through ioctl
1221  *
1222  *      @file: the file
1223  *      @cmd: the command
1224  *      @arg: command arg
1225  *
1226  *      This ioctl implements lttng commands:
1227  *      LTTNG_KERNEL_STREAM
1228  *              Returns an event stream file descriptor or failure.
1229  *
1230  * Channel and event file descriptors also hold a reference on the session.
1231  */
1232 static
1233 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1234 {
1235         switch (cmd) {
1236         case LTTNG_KERNEL_OLD_STREAM:
1237         case LTTNG_KERNEL_STREAM:
1238                 return lttng_abi_open_metadata_stream(file);
1239         default:
1240                 return -ENOIOCTLCMD;
1241         }
1242 }
1243
1244 /**
1245  *      lttng_channel_poll - lttng stream addition/removal monitoring
1246  *
1247  *      @file: the file
1248  *      @wait: poll table
1249  */
1250 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1251 {
1252         struct lttng_channel *channel = file->private_data;
1253         unsigned int mask = 0;
1254
1255         if (file->f_mode & FMODE_READ) {
1256                 poll_wait_set_exclusive(wait);
1257                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1258                           wait);
1259
1260                 if (channel->ops->is_disabled(channel->chan))
1261                         return POLLERR;
1262                 if (channel->ops->is_finalized(channel->chan))
1263                         return POLLHUP;
1264                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1265                         return POLLIN | POLLRDNORM;
1266                 return 0;
1267         }
1268         return mask;
1269
1270 }
1271
1272 static
1273 int lttng_channel_release(struct inode *inode, struct file *file)
1274 {
1275         struct lttng_channel *channel = file->private_data;
1276
1277         if (channel)
1278                 fput(channel->session->file);
1279         return 0;
1280 }
1281
1282 static
1283 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1284 {
1285         struct lttng_channel *channel = file->private_data;
1286
1287         if (channel) {
1288                 lttng_metadata_channel_destroy(channel);
1289                 fput(channel->session->file);
1290         }
1291
1292         return 0;
1293 }
1294
1295 static const struct file_operations lttng_channel_fops = {
1296         .owner = THIS_MODULE,
1297         .release = lttng_channel_release,
1298         .poll = lttng_channel_poll,
1299         .unlocked_ioctl = lttng_channel_ioctl,
1300 #ifdef CONFIG_COMPAT
1301         .compat_ioctl = lttng_channel_ioctl,
1302 #endif
1303 };
1304
1305 static const struct file_operations lttng_metadata_fops = {
1306         .owner = THIS_MODULE,
1307         .release = lttng_metadata_channel_release,
1308         .unlocked_ioctl = lttng_metadata_ioctl,
1309 #ifdef CONFIG_COMPAT
1310         .compat_ioctl = lttng_metadata_ioctl,
1311 #endif
1312 };
1313
1314 /**
1315  *      lttng_event_ioctl - lttng syscall through ioctl
1316  *
1317  *      @file: the file
1318  *      @cmd: the command
1319  *      @arg: command arg
1320  *
1321  *      This ioctl implements lttng commands:
1322  *      LTTNG_KERNEL_CONTEXT
1323  *              Prepend a context field to each record of this event
1324  *      LTTNG_KERNEL_ENABLE
1325  *              Enable recording for this event (weak enable)
1326  *      LTTNG_KERNEL_DISABLE
1327  *              Disable recording for this event (strong disable)
1328  */
1329 static
1330 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1331 {
1332         struct lttng_event *event;
1333         struct lttng_enabler *enabler;
1334         enum lttng_event_type *evtype = file->private_data;
1335
1336         switch (cmd) {
1337         case LTTNG_KERNEL_OLD_CONTEXT:
1338         {
1339                 /* Not implemented */
1340                 return -ENOSYS;
1341         }
1342         case LTTNG_KERNEL_CONTEXT:
1343         {
1344                 /* Not implemented */
1345                 return -ENOSYS;
1346         }
1347         case LTTNG_KERNEL_OLD_ENABLE:
1348         case LTTNG_KERNEL_ENABLE:
1349                 switch (*evtype) {
1350                 case LTTNG_TYPE_EVENT:
1351                         event = file->private_data;
1352                         return lttng_event_enable(event);
1353                 case LTTNG_TYPE_ENABLER:
1354                         enabler = file->private_data;
1355                         return lttng_enabler_enable(enabler);
1356                 default:
1357                         WARN_ON_ONCE(1);
1358                         return -ENOSYS;
1359                 }
1360         case LTTNG_KERNEL_OLD_DISABLE:
1361         case LTTNG_KERNEL_DISABLE:
1362                 switch (*evtype) {
1363                 case LTTNG_TYPE_EVENT:
1364                         event = file->private_data;
1365                         return lttng_event_disable(event);
1366                 case LTTNG_TYPE_ENABLER:
1367                         enabler = file->private_data;
1368                         return lttng_enabler_disable(enabler);
1369                 default:
1370                         WARN_ON_ONCE(1);
1371                         return -ENOSYS;
1372                 }
1373         case LTTNG_KERNEL_FILTER:
1374                 switch (*evtype) {
1375                 case LTTNG_TYPE_EVENT:
1376                         return -EINVAL;
1377                 case LTTNG_TYPE_ENABLER:
1378                 {
1379                         enabler = file->private_data;
1380                         return lttng_enabler_attach_bytecode(enabler,
1381                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1382                 }
1383
1384                 }
1385         default:
1386                 return -ENOIOCTLCMD;
1387         }
1388 }
1389
1390 static
1391 int lttng_event_release(struct inode *inode, struct file *file)
1392 {
1393         struct lttng_event *event;
1394         struct lttng_enabler *enabler;
1395         enum lttng_event_type *evtype = file->private_data;
1396
1397         if (!evtype)
1398                 return 0;
1399
1400         switch (*evtype) {
1401         case LTTNG_TYPE_EVENT:
1402                 event = file->private_data;
1403                 if (event)
1404                         fput(event->chan->file);
1405                 break;
1406         case LTTNG_TYPE_ENABLER:
1407                 enabler = file->private_data;
1408                 if (enabler)
1409                         fput(enabler->chan->file);
1410                 break;
1411         default:
1412                 WARN_ON_ONCE(1);
1413                 break;
1414         }
1415
1416         return 0;
1417 }
1418
1419 /* TODO: filter control ioctl */
1420 static const struct file_operations lttng_event_fops = {
1421         .owner = THIS_MODULE,
1422         .release = lttng_event_release,
1423         .unlocked_ioctl = lttng_event_ioctl,
1424 #ifdef CONFIG_COMPAT
1425         .compat_ioctl = lttng_event_ioctl,
1426 #endif
1427 };
1428
1429 static int put_u64(uint64_t val, unsigned long arg)
1430 {
1431         return put_user(val, (uint64_t __user *) arg);
1432 }
1433
1434 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1435                 unsigned int cmd, unsigned long arg)
1436 {
1437         struct lib_ring_buffer *buf = filp->private_data;
1438         struct channel *chan = buf->backend.chan;
1439         const struct lib_ring_buffer_config *config = &chan->backend.config;
1440         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1441         int ret;
1442
1443         if (atomic_read(&chan->record_disabled))
1444                 return -EIO;
1445
1446         switch (cmd) {
1447         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1448         {
1449                 uint64_t ts;
1450
1451                 ret = ops->timestamp_begin(config, buf, &ts);
1452                 if (ret < 0)
1453                         goto error;
1454                 return put_u64(ts, arg);
1455         }
1456         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1457         {
1458                 uint64_t ts;
1459
1460                 ret = ops->timestamp_end(config, buf, &ts);
1461                 if (ret < 0)
1462                         goto error;
1463                 return put_u64(ts, arg);
1464         }
1465         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1466         {
1467                 uint64_t ed;
1468
1469                 ret = ops->events_discarded(config, buf, &ed);
1470                 if (ret < 0)
1471                         goto error;
1472                 return put_u64(ed, arg);
1473         }
1474         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1475         {
1476                 uint64_t cs;
1477
1478                 ret = ops->content_size(config, buf, &cs);
1479                 if (ret < 0)
1480                         goto error;
1481                 return put_u64(cs, arg);
1482         }
1483         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1484         {
1485                 uint64_t ps;
1486
1487                 ret = ops->packet_size(config, buf, &ps);
1488                 if (ret < 0)
1489                         goto error;
1490                 return put_u64(ps, arg);
1491         }
1492         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1493         {
1494                 uint64_t si;
1495
1496                 ret = ops->stream_id(config, buf, &si);
1497                 if (ret < 0)
1498                         goto error;
1499                 return put_u64(si, arg);
1500         }
1501         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1502         {
1503                 uint64_t ts;
1504
1505                 ret = ops->current_timestamp(config, buf, &ts);
1506                 if (ret < 0)
1507                         goto error;
1508                 return put_u64(ts, arg);
1509         }
1510         default:
1511                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1512                                 cmd, arg);
1513         }
1514
1515 error:
1516         return -ENOSYS;
1517 }
1518
1519 #ifdef CONFIG_COMPAT
1520 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1521                 unsigned int cmd, unsigned long arg)
1522 {
1523         struct lib_ring_buffer *buf = filp->private_data;
1524         struct channel *chan = buf->backend.chan;
1525         const struct lib_ring_buffer_config *config = &chan->backend.config;
1526         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1527         int ret;
1528
1529         if (atomic_read(&chan->record_disabled))
1530                 return -EIO;
1531
1532         switch (cmd) {
1533         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1534         {
1535                 uint64_t ts;
1536
1537                 ret = ops->timestamp_begin(config, buf, &ts);
1538                 if (ret < 0)
1539                         goto error;
1540                 return put_u64(ts, arg);
1541         }
1542         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1543         {
1544                 uint64_t ts;
1545
1546                 ret = ops->timestamp_end(config, buf, &ts);
1547                 if (ret < 0)
1548                         goto error;
1549                 return put_u64(ts, arg);
1550         }
1551         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1552         {
1553                 uint64_t ed;
1554
1555                 ret = ops->events_discarded(config, buf, &ed);
1556                 if (ret < 0)
1557                         goto error;
1558                 return put_u64(ed, arg);
1559         }
1560         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1561         {
1562                 uint64_t cs;
1563
1564                 ret = ops->content_size(config, buf, &cs);
1565                 if (ret < 0)
1566                         goto error;
1567                 return put_u64(cs, arg);
1568         }
1569         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1570         {
1571                 uint64_t ps;
1572
1573                 ret = ops->packet_size(config, buf, &ps);
1574                 if (ret < 0)
1575                         goto error;
1576                 return put_u64(ps, arg);
1577         }
1578         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1579         {
1580                 uint64_t si;
1581
1582                 ret = ops->stream_id(config, buf, &si);
1583                 if (ret < 0)
1584                         goto error;
1585                 return put_u64(si, arg);
1586         }
1587         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1588         {
1589                 uint64_t ts;
1590
1591                 ret = ops->current_timestamp(config, buf, &ts);
1592                 if (ret < 0)
1593                         goto error;
1594                 return put_u64(ts, arg);
1595         }
1596         default:
1597                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1598                                 cmd, arg);
1599         }
1600
1601 error:
1602         return -ENOSYS;
1603 }
1604 #endif /* CONFIG_COMPAT */
1605
1606 static void lttng_stream_override_ring_buffer_fops(void)
1607 {
1608         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1609         lttng_stream_ring_buffer_file_operations.open =
1610                 lib_ring_buffer_file_operations.open;
1611         lttng_stream_ring_buffer_file_operations.release =
1612                 lib_ring_buffer_file_operations.release;
1613         lttng_stream_ring_buffer_file_operations.poll =
1614                 lib_ring_buffer_file_operations.poll;
1615         lttng_stream_ring_buffer_file_operations.splice_read =
1616                 lib_ring_buffer_file_operations.splice_read;
1617         lttng_stream_ring_buffer_file_operations.mmap =
1618                 lib_ring_buffer_file_operations.mmap;
1619         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1620                 lttng_stream_ring_buffer_ioctl;
1621         lttng_stream_ring_buffer_file_operations.llseek =
1622                 lib_ring_buffer_file_operations.llseek;
1623 #ifdef CONFIG_COMPAT
1624         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1625                 lttng_stream_ring_buffer_compat_ioctl;
1626 #endif
1627 }
1628
1629 int __init lttng_abi_init(void)
1630 {
1631         int ret = 0;
1632
1633         wrapper_vmalloc_sync_all();
1634         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1635                                         &lttng_fops, NULL);
1636
1637         if (!lttng_proc_dentry) {
1638                 printk(KERN_ERR "Error creating LTTng control file\n");
1639                 ret = -ENOMEM;
1640                 goto error;
1641         }
1642         lttng_stream_override_ring_buffer_fops();
1643
1644 error:
1645         return ret;
1646 }
1647
1648 /* No __exit annotation because used by init error path too. */
1649 void lttng_abi_exit(void)
1650 {
1651         if (lttng_proc_dentry)
1652                 remove_proc_entry("lttng", NULL);
1653 }