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                 mutex_lock(&stream->metadata_cache->lock);
 626                 if (stream->metadata_cache->metadata_written >
 627                                 stream->metadata_out)
 628                         mask |= POLLIN;
 629                 mutex_unlock(&stream->metadata_cache->lock);
 630         }
 631
 632         return mask;
 633 }
 634
 635 static
 636 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 637                 unsigned int cmd, unsigned long arg)
 638 {
 639         struct lttng_metadata_stream *stream = filp->private_data;
 640
 641         stream->metadata_out = stream->metadata_in;
 642 }
 643
 644 static
 645 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 646                 unsigned int cmd, unsigned long arg)
 647 {
 648         int ret;
 649         struct lttng_metadata_stream *stream = filp->private_data;
 650         struct lib_ring_buffer *buf = stream->priv;
 651
 652         switch (cmd) {
 653         case RING_BUFFER_GET_NEXT_SUBBUF:
 654         {
 655                 struct lttng_metadata_stream *stream = filp->private_data;
 656                 struct lib_ring_buffer *buf = stream->priv;
 657                 struct channel *chan = buf->backend.chan;
 658
 659                 ret = lttng_metadata_output_channel(stream, chan);
 660                 if (ret > 0) {
 661                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 662                         ret = 0;
 663                 } else if (ret < 0)
 664                         goto err;
 665                 break;
 666         }
 667         case RING_BUFFER_GET_SUBBUF:
 668         {
 669                 /*
 670                  * Random access is not allowed for metadata channel.
 671                  */
 672                 return -ENOSYS;
 673         }
 674         case RING_BUFFER_FLUSH:
 675         {
 676                 struct lttng_metadata_stream *stream = filp->private_data;
 677                 struct lib_ring_buffer *buf = stream->priv;
 678                 struct channel *chan = buf->backend.chan;
 679
 680                 /*
 681                  * Before doing the actual ring buffer flush, write up to one
 682                  * packet of metadata in the ring buffer.
 683                  */
 684                 ret = lttng_metadata_output_channel(stream, chan);
 685                 if (ret < 0)
 686                         goto err;
 687                 break;
 688         }
 689         default:
 690                 break;
 691         }
 692         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 693
 694         /* Performing lib ring buffer ioctl after our own. */
 695         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 696         if (ret < 0)
 697                 goto err;
 698
 699         switch (cmd) {
 700         case RING_BUFFER_PUT_NEXT_SUBBUF:
 701         {
 702                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 703                                 cmd, arg);
 704                 break;
 705         }
 706         default:
 707                 break;
 708         }
 709 err:
 710         return ret;
 711 }
 712
 713 #ifdef CONFIG_COMPAT
 714 static
 715 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 716                 unsigned int cmd, unsigned long arg)
 717 {
 718         int ret;
 719         struct lttng_metadata_stream *stream = filp->private_data;
 720         struct lib_ring_buffer *buf = stream->priv;
 721
 722         switch (cmd) {
 723         case RING_BUFFER_GET_NEXT_SUBBUF:
 724         {
 725                 struct lttng_metadata_stream *stream = filp->private_data;
 726                 struct lib_ring_buffer *buf = stream->priv;
 727                 struct channel *chan = buf->backend.chan;
 728
 729                 ret = lttng_metadata_output_channel(stream, chan);
 730                 if (ret > 0) {
 731                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 732                         ret = 0;
 733                 } else if (ret < 0)
 734                         goto err;
 735                 break;
 736         }
 737         case RING_BUFFER_GET_SUBBUF:
 738         {
 739                 /*
 740                  * Random access is not allowed for metadata channel.
 741                  */
 742                 return -ENOSYS;
 743         }
 744         default:
 745                 break;
 746         }
 747         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 748
 749         /* Performing lib ring buffer ioctl after our own. */
 750         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 751         if (ret < 0)
 752                 goto err;
 753
 754         switch (cmd) {
 755         case RING_BUFFER_PUT_NEXT_SUBBUF:
 756         {
 757                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 758                                 cmd, arg);
 759                 break;
 760         }
 761         default:
 762                 break;
 763         }
 764 err:
 765         return ret;
 766 }
 767 #endif
 768
 769 /*
 770  * This is not used by anonymous file descriptors. This code is left
 771  * there if we ever want to implement an inode with open() operation.
 772  */
 773 static
 774 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 775 {
 776         struct lttng_metadata_stream *stream = inode->i_private;
 777         struct lib_ring_buffer *buf = stream->priv;
 778
 779         file->private_data = buf;
 780         /*
 781          * Since life-time of metadata cache differs from that of
 782          * session, we need to keep our own reference on the transport.
 783          */
 784         if (!try_module_get(stream->transport->owner)) {
 785                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 786                 return -EBUSY;
 787         }
 788         return lib_ring_buffer_open(inode, file, buf);
 789 }
 790
 791 static
 792 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 793 {
 794         struct lttng_metadata_stream *stream = file->private_data;
 795         struct lib_ring_buffer *buf = stream->priv;
 796
 797         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 798         module_put(stream->transport->owner);
 799         return lib_ring_buffer_release(inode, file, buf);
 800 }
 801
 802 static
 803 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 804                 struct pipe_inode_info *pipe, size_t len,
 805                 unsigned int flags)
 806 {
 807         struct lttng_metadata_stream *stream = in->private_data;
 808         struct lib_ring_buffer *buf = stream->priv;
 809
 810         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 811                         flags, buf);
 812 }
 813
 814 static
 815 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 816                 struct vm_area_struct *vma)
 817 {
 818         struct lttng_metadata_stream *stream = filp->private_data;
 819         struct lib_ring_buffer *buf = stream->priv;
 820
 821         return lib_ring_buffer_mmap(filp, vma, buf);
 822 }
 823
 824 static
 825 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 826         .owner = THIS_MODULE,
 827         .open = lttng_metadata_ring_buffer_open,
 828         .release = lttng_metadata_ring_buffer_release,
 829         .poll = lttng_metadata_ring_buffer_poll,
 830         .splice_read = lttng_metadata_ring_buffer_splice_read,
 831         .mmap = lttng_metadata_ring_buffer_mmap,
 832         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 833         .llseek = vfs_lib_ring_buffer_no_llseek,
 834 #ifdef CONFIG_COMPAT
 835         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 836 #endif
 837 };
 838
 839 static
 840 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 841                 const struct file_operations *fops)
 842 {
 843         int stream_fd, ret;
 844         struct file *stream_file;
 845
 846         stream_fd = lttng_get_unused_fd();
 847         if (stream_fd < 0) {
 848                 ret = stream_fd;
 849                 goto fd_error;
 850         }
 851         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 852                         stream_priv, O_RDWR);
 853         if (IS_ERR(stream_file)) {
 854                 ret = PTR_ERR(stream_file);
 855                 goto file_error;
 856         }
 857         /*
 858          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 859          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 860          * file descriptor, so we set FMODE_PREAD here.
 861          */
 862         stream_file->f_mode |= FMODE_PREAD;
 863         fd_install(stream_fd, stream_file);
 864         /*
 865          * The stream holds a reference to the channel within the generic ring
 866          * buffer library, so no need to hold a refcount on the channel and
 867          * session files here.
 868          */
 869         return stream_fd;
 870
 871 file_error:
 872         put_unused_fd(stream_fd);
 873 fd_error:
 874         return ret;
 875 }
 876
 877 static
 878 int lttng_abi_open_stream(struct file *channel_file)
 879 {
 880         struct lttng_channel *channel = channel_file->private_data;
 881         struct lib_ring_buffer *buf;
 882         int ret;
 883         void *stream_priv;
 884
 885         buf = channel->ops->buffer_read_open(channel->chan);
 886         if (!buf)
 887                 return -ENOENT;
 888
 889         stream_priv = buf;
 890         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 891                         &lttng_stream_ring_buffer_file_operations);
 892         if (ret < 0)
 893                 goto fd_error;
 894
 895         return ret;
 896
 897 fd_error:
 898         channel->ops->buffer_read_close(buf);
 899         return ret;
 900 }
 901
 902 static
 903 int lttng_abi_open_metadata_stream(struct file *channel_file)
 904 {
 905         struct lttng_channel *channel = channel_file->private_data;
 906         struct lttng_session *session = channel->session;
 907         struct lib_ring_buffer *buf;
 908         int ret;
 909         struct lttng_metadata_stream *metadata_stream;
 910         void *stream_priv;
 911
 912         buf = channel->ops->buffer_read_open(channel->chan);
 913         if (!buf)
 914                 return -ENOENT;
 915
 916         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 917                         GFP_KERNEL);
 918         if (!metadata_stream) {
 919                 ret = -ENOMEM;
 920                 goto nomem;
 921         }
 922         metadata_stream->metadata_cache = session->metadata_cache;
 923         init_waitqueue_head(&metadata_stream->read_wait);
 924         metadata_stream->priv = buf;
 925         stream_priv = metadata_stream;
 926         metadata_stream->transport = channel->transport;
 927
 928         /*
 929          * Since life-time of metadata cache differs from that of
 930          * session, we need to keep our own reference on the transport.
 931          */
 932         if (!try_module_get(metadata_stream->transport->owner)) {
 933                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 934                 ret = -EINVAL;
 935                 goto notransport;
 936         }
 937
 938         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 939                         &lttng_metadata_ring_buffer_file_operations);
 940         if (ret < 0)
 941                 goto fd_error;
 942
 943         kref_get(&session->metadata_cache->refcount);
 944         list_add(&metadata_stream->list,
 945                 &session->metadata_cache->metadata_stream);
 946         return ret;
 947
 948 fd_error:
 949         module_put(metadata_stream->transport->owner);
 950 notransport:
 951         kfree(metadata_stream);
 952 nomem:
 953         channel->ops->buffer_read_close(buf);
 954         return ret;
 955 }
 956
 957 static
 958 int lttng_abi_create_event(struct file *channel_file,
 959                            struct lttng_kernel_event *event_param)
 960 {
 961         struct lttng_channel *channel = channel_file->private_data;
 962         int event_fd, ret;
 963         struct file *event_file;
 964         void *priv;
 965
 966         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 967         switch (event_param->instrumentation) {
 968         case LTTNG_KERNEL_KRETPROBE:
 969                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 970                 break;
 971         case LTTNG_KERNEL_KPROBE:
 972                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 973                 break;
 974         case LTTNG_KERNEL_FUNCTION:
 975                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 976                 break;
 977         default:
 978                 break;
 979         }
 980         event_fd = lttng_get_unused_fd();
 981         if (event_fd < 0) {
 982                 ret = event_fd;
 983                 goto fd_error;
 984         }
 985         event_file = anon_inode_getfile("[lttng_event]",
 986                                         &lttng_event_fops,
 987                                         NULL, O_RDWR);
 988         if (IS_ERR(event_file)) {
 989                 ret = PTR_ERR(event_file);
 990                 goto file_error;
 991         }
 992         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
 993                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
 994                 struct lttng_enabler *enabler;
 995
 996                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
 997                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
 998                                 event_param, channel);
 999                 } else {
1000                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1001                                 event_param, channel);
1002                 }
1003                 priv = enabler;
1004         } else {
1005                 struct lttng_event *event;
1006
1007                 /*
1008                  * We tolerate no failure path after event creation. It
1009                  * will stay invariant for the rest of the session.
1010                  */
1011                 event = lttng_event_create(channel, event_param,
1012                                 NULL, NULL,
1013                                 event_param->instrumentation);
1014                 WARN_ON_ONCE(!event);
1015                 if (IS_ERR(event)) {
1016                         ret = PTR_ERR(event);
1017                         goto event_error;
1018                 }
1019                 priv = event;
1020         }
1021         event_file->private_data = priv;
1022         fd_install(event_fd, event_file);
1023         /* The event holds a reference on the channel */
1024         atomic_long_inc(&channel_file->f_count);
1025         return event_fd;
1026
1027 event_error:
1028         fput(event_file);
1029 file_error:
1030         put_unused_fd(event_fd);
1031 fd_error:
1032         return ret;
1033 }
1034
1035 /**
1036  *      lttng_channel_ioctl - lttng syscall through ioctl
1037  *
1038  *      @file: the file
1039  *      @cmd: the command
1040  *      @arg: command arg
1041  *
1042  *      This ioctl implements lttng commands:
1043  *      LTTNG_KERNEL_STREAM
1044  *              Returns an event stream file descriptor or failure.
1045  *              (typically, one event stream records events from one CPU)
1046  *      LTTNG_KERNEL_EVENT
1047  *              Returns an event file descriptor or failure.
1048  *      LTTNG_KERNEL_CONTEXT
1049  *              Prepend a context field to each event in the channel
1050  *      LTTNG_KERNEL_ENABLE
1051  *              Enable recording for events in this channel (weak enable)
1052  *      LTTNG_KERNEL_DISABLE
1053  *              Disable recording for events in this channel (strong disable)
1054  *
1055  * Channel and event file descriptors also hold a reference on the session.
1056  */
1057 static
1058 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1059 {
1060         struct lttng_channel *channel = file->private_data;
1061
1062         switch (cmd) {
1063         case LTTNG_KERNEL_OLD_STREAM:
1064         case LTTNG_KERNEL_STREAM:
1065                 return lttng_abi_open_stream(file);
1066         case LTTNG_KERNEL_OLD_EVENT:
1067         {
1068                 struct lttng_kernel_event *uevent_param;
1069                 struct lttng_kernel_old_event *old_uevent_param;
1070                 int ret;
1071
1072                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1073                                 GFP_KERNEL);
1074                 if (!uevent_param) {
1075                         ret = -ENOMEM;
1076                         goto old_event_end;
1077                 }
1078                 old_uevent_param = kmalloc(
1079                                 sizeof(struct lttng_kernel_old_event),
1080                                 GFP_KERNEL);
1081                 if (!old_uevent_param) {
1082                         ret = -ENOMEM;
1083                         goto old_event_error_free_param;
1084                 }
1085                 if (copy_from_user(old_uevent_param,
1086                                 (struct lttng_kernel_old_event __user *) arg,
1087                                 sizeof(struct lttng_kernel_old_event))) {
1088                         ret = -EFAULT;
1089                         goto old_event_error_free_old_param;
1090                 }
1091
1092                 memcpy(uevent_param->name, old_uevent_param->name,
1093                                 sizeof(uevent_param->name));
1094                 uevent_param->instrumentation =
1095                         old_uevent_param->instrumentation;
1096
1097                 switch (old_uevent_param->instrumentation) {
1098                 case LTTNG_KERNEL_KPROBE:
1099                         uevent_param->u.kprobe.addr =
1100                                 old_uevent_param->u.kprobe.addr;
1101                         uevent_param->u.kprobe.offset =
1102                                 old_uevent_param->u.kprobe.offset;
1103                         memcpy(uevent_param->u.kprobe.symbol_name,
1104                                 old_uevent_param->u.kprobe.symbol_name,
1105                                 sizeof(uevent_param->u.kprobe.symbol_name));
1106                         break;
1107                 case LTTNG_KERNEL_KRETPROBE:
1108                         uevent_param->u.kretprobe.addr =
1109                                 old_uevent_param->u.kretprobe.addr;
1110                         uevent_param->u.kretprobe.offset =
1111                                 old_uevent_param->u.kretprobe.offset;
1112                         memcpy(uevent_param->u.kretprobe.symbol_name,
1113                                 old_uevent_param->u.kretprobe.symbol_name,
1114                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1115                         break;
1116                 case LTTNG_KERNEL_FUNCTION:
1117                         memcpy(uevent_param->u.ftrace.symbol_name,
1118                                         old_uevent_param->u.ftrace.symbol_name,
1119                                         sizeof(uevent_param->u.ftrace.symbol_name));
1120                         break;
1121                 default:
1122                         break;
1123                 }
1124                 ret = lttng_abi_create_event(file, uevent_param);
1125
1126 old_event_error_free_old_param:
1127                 kfree(old_uevent_param);
1128 old_event_error_free_param:
1129                 kfree(uevent_param);
1130 old_event_end:
1131                 return ret;
1132         }
1133         case LTTNG_KERNEL_EVENT:
1134         {
1135                 struct lttng_kernel_event uevent_param;
1136
1137                 if (copy_from_user(&uevent_param,
1138                                 (struct lttng_kernel_event __user *) arg,
1139                                 sizeof(uevent_param)))
1140                         return -EFAULT;
1141                 return lttng_abi_create_event(file, &uevent_param);
1142         }
1143         case LTTNG_KERNEL_OLD_CONTEXT:
1144         {
1145                 struct lttng_kernel_context *ucontext_param;
1146                 struct lttng_kernel_old_context *old_ucontext_param;
1147                 int ret;
1148
1149                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1150                                 GFP_KERNEL);
1151                 if (!ucontext_param) {
1152                         ret = -ENOMEM;
1153                         goto old_ctx_end;
1154                 }
1155                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1156                                 GFP_KERNEL);
1157                 if (!old_ucontext_param) {
1158                         ret = -ENOMEM;
1159                         goto old_ctx_error_free_param;
1160                 }
1161
1162                 if (copy_from_user(old_ucontext_param,
1163                                 (struct lttng_kernel_old_context __user *) arg,
1164                                 sizeof(struct lttng_kernel_old_context))) {
1165                         ret = -EFAULT;
1166                         goto old_ctx_error_free_old_param;
1167                 }
1168                 ucontext_param->ctx = old_ucontext_param->ctx;
1169                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1170                                 sizeof(ucontext_param->padding));
1171                 /* only type that uses the union */
1172                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1173                         ucontext_param->u.perf_counter.type =
1174                                 old_ucontext_param->u.perf_counter.type;
1175                         ucontext_param->u.perf_counter.config =
1176                                 old_ucontext_param->u.perf_counter.config;
1177                         memcpy(ucontext_param->u.perf_counter.name,
1178                                 old_ucontext_param->u.perf_counter.name,
1179                                 sizeof(ucontext_param->u.perf_counter.name));
1180                 }
1181
1182                 ret = lttng_abi_add_context(file,
1183                                 ucontext_param,
1184                                 &channel->ctx, channel->session);
1185
1186 old_ctx_error_free_old_param:
1187                 kfree(old_ucontext_param);
1188 old_ctx_error_free_param:
1189                 kfree(ucontext_param);
1190 old_ctx_end:
1191                 return ret;
1192         }
1193         case LTTNG_KERNEL_CONTEXT:
1194         {
1195                 struct lttng_kernel_context ucontext_param;
1196
1197                 if (copy_from_user(&ucontext_param,
1198                                 (struct lttng_kernel_context __user *) arg,
1199                                 sizeof(ucontext_param)))
1200                         return -EFAULT;
1201                 return lttng_abi_add_context(file,
1202                                 &ucontext_param,
1203                                 &channel->ctx, channel->session);
1204         }
1205         case LTTNG_KERNEL_OLD_ENABLE:
1206         case LTTNG_KERNEL_ENABLE:
1207                 return lttng_channel_enable(channel);
1208         case LTTNG_KERNEL_OLD_DISABLE:
1209         case LTTNG_KERNEL_DISABLE:
1210                 return lttng_channel_disable(channel);
1211         case LTTNG_KERNEL_SYSCALL_MASK:
1212                 return lttng_channel_syscall_mask(channel,
1213                         (struct lttng_kernel_syscall_mask __user *) arg);
1214         default:
1215                 return -ENOIOCTLCMD;
1216         }
1217
1218 }
1219
1220 /**
1221  *      lttng_metadata_ioctl - lttng syscall through ioctl
1222  *
1223  *      @file: the file
1224  *      @cmd: the command
1225  *      @arg: command arg
1226  *
1227  *      This ioctl implements lttng commands:
1228  *      LTTNG_KERNEL_STREAM
1229  *              Returns an event stream file descriptor or failure.
1230  *
1231  * Channel and event file descriptors also hold a reference on the session.
1232  */
1233 static
1234 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1235 {
1236         switch (cmd) {
1237         case LTTNG_KERNEL_OLD_STREAM:
1238         case LTTNG_KERNEL_STREAM:
1239                 return lttng_abi_open_metadata_stream(file);
1240         default:
1241                 return -ENOIOCTLCMD;
1242         }
1243 }
1244
1245 /**
1246  *      lttng_channel_poll - lttng stream addition/removal monitoring
1247  *
1248  *      @file: the file
1249  *      @wait: poll table
1250  */
1251 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1252 {
1253         struct lttng_channel *channel = file->private_data;
1254         unsigned int mask = 0;
1255
1256         if (file->f_mode & FMODE_READ) {
1257                 poll_wait_set_exclusive(wait);
1258                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1259                           wait);
1260
1261                 if (channel->ops->is_disabled(channel->chan))
1262                         return POLLERR;
1263                 if (channel->ops->is_finalized(channel->chan))
1264                         return POLLHUP;
1265                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1266                         return POLLIN | POLLRDNORM;
1267                 return 0;
1268         }
1269         return mask;
1270
1271 }
1272
1273 static
1274 int lttng_channel_release(struct inode *inode, struct file *file)
1275 {
1276         struct lttng_channel *channel = file->private_data;
1277
1278         if (channel)
1279                 fput(channel->session->file);
1280         return 0;
1281 }
1282
1283 static
1284 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1285 {
1286         struct lttng_channel *channel = file->private_data;
1287
1288         if (channel) {
1289                 lttng_metadata_channel_destroy(channel);
1290                 fput(channel->session->file);
1291         }
1292
1293         return 0;
1294 }
1295
1296 static const struct file_operations lttng_channel_fops = {
1297         .owner = THIS_MODULE,
1298         .release = lttng_channel_release,
1299         .poll = lttng_channel_poll,
1300         .unlocked_ioctl = lttng_channel_ioctl,
1301 #ifdef CONFIG_COMPAT
1302         .compat_ioctl = lttng_channel_ioctl,
1303 #endif
1304 };
1305
1306 static const struct file_operations lttng_metadata_fops = {
1307         .owner = THIS_MODULE,
1308         .release = lttng_metadata_channel_release,
1309         .unlocked_ioctl = lttng_metadata_ioctl,
1310 #ifdef CONFIG_COMPAT
1311         .compat_ioctl = lttng_metadata_ioctl,
1312 #endif
1313 };
1314
1315 /**
1316  *      lttng_event_ioctl - lttng syscall through ioctl
1317  *
1318  *      @file: the file
1319  *      @cmd: the command
1320  *      @arg: command arg
1321  *
1322  *      This ioctl implements lttng commands:
1323  *      LTTNG_KERNEL_CONTEXT
1324  *              Prepend a context field to each record of this event
1325  *      LTTNG_KERNEL_ENABLE
1326  *              Enable recording for this event (weak enable)
1327  *      LTTNG_KERNEL_DISABLE
1328  *              Disable recording for this event (strong disable)
1329  */
1330 static
1331 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1332 {
1333         struct lttng_event *event;
1334         struct lttng_enabler *enabler;
1335         enum lttng_event_type *evtype = file->private_data;
1336
1337         switch (cmd) {
1338         case LTTNG_KERNEL_OLD_CONTEXT:
1339         {
1340                 /* Not implemented */
1341                 return -ENOSYS;
1342         }
1343         case LTTNG_KERNEL_CONTEXT:
1344         {
1345                 /* Not implemented */
1346                 return -ENOSYS;
1347         }
1348         case LTTNG_KERNEL_OLD_ENABLE:
1349         case LTTNG_KERNEL_ENABLE:
1350                 switch (*evtype) {
1351                 case LTTNG_TYPE_EVENT:
1352                         event = file->private_data;
1353                         return lttng_event_enable(event);
1354                 case LTTNG_TYPE_ENABLER:
1355                         enabler = file->private_data;
1356                         return lttng_enabler_enable(enabler);
1357                 default:
1358                         WARN_ON_ONCE(1);
1359                         return -ENOSYS;
1360                 }
1361         case LTTNG_KERNEL_OLD_DISABLE:
1362         case LTTNG_KERNEL_DISABLE:
1363                 switch (*evtype) {
1364                 case LTTNG_TYPE_EVENT:
1365                         event = file->private_data;
1366                         return lttng_event_disable(event);
1367                 case LTTNG_TYPE_ENABLER:
1368                         enabler = file->private_data;
1369                         return lttng_enabler_disable(enabler);
1370                 default:
1371                         WARN_ON_ONCE(1);
1372                         return -ENOSYS;
1373                 }
1374         case LTTNG_KERNEL_FILTER:
1375                 switch (*evtype) {
1376                 case LTTNG_TYPE_EVENT:
1377                         return -EINVAL;
1378                 case LTTNG_TYPE_ENABLER:
1379                 {
1380                         enabler = file->private_data;
1381                         return lttng_enabler_attach_bytecode(enabler,
1382                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1383                 }
1384
1385                 }
1386         default:
1387                 return -ENOIOCTLCMD;
1388         }
1389 }
1390
1391 static
1392 int lttng_event_release(struct inode *inode, struct file *file)
1393 {
1394         struct lttng_event *event;
1395         struct lttng_enabler *enabler;
1396         enum lttng_event_type *evtype = file->private_data;
1397
1398         if (!evtype)
1399                 return 0;
1400
1401         switch (*evtype) {
1402         case LTTNG_TYPE_EVENT:
1403                 event = file->private_data;
1404                 if (event)
1405                         fput(event->chan->file);
1406                 break;
1407         case LTTNG_TYPE_ENABLER:
1408                 enabler = file->private_data;
1409                 if (enabler)
1410                         fput(enabler->chan->file);
1411                 break;
1412         default:
1413                 WARN_ON_ONCE(1);
1414                 break;
1415         }
1416
1417         return 0;
1418 }
1419
1420 /* TODO: filter control ioctl */
1421 static const struct file_operations lttng_event_fops = {
1422         .owner = THIS_MODULE,
1423         .release = lttng_event_release,
1424         .unlocked_ioctl = lttng_event_ioctl,
1425 #ifdef CONFIG_COMPAT
1426         .compat_ioctl = lttng_event_ioctl,
1427 #endif
1428 };
1429
1430 static int put_u64(uint64_t val, unsigned long arg)
1431 {
1432         return put_user(val, (uint64_t __user *) arg);
1433 }
1434
1435 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1436                 unsigned int cmd, unsigned long arg)
1437 {
1438         struct lib_ring_buffer *buf = filp->private_data;
1439         struct channel *chan = buf->backend.chan;
1440         const struct lib_ring_buffer_config *config = &chan->backend.config;
1441         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1442         int ret;
1443
1444         if (atomic_read(&chan->record_disabled))
1445                 return -EIO;
1446
1447         switch (cmd) {
1448         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1449         {
1450                 uint64_t ts;
1451
1452                 ret = ops->timestamp_begin(config, buf, &ts);
1453                 if (ret < 0)
1454                         goto error;
1455                 return put_u64(ts, arg);
1456         }
1457         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1458         {
1459                 uint64_t ts;
1460
1461                 ret = ops->timestamp_end(config, buf, &ts);
1462                 if (ret < 0)
1463                         goto error;
1464                 return put_u64(ts, arg);
1465         }
1466         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1467         {
1468                 uint64_t ed;
1469
1470                 ret = ops->events_discarded(config, buf, &ed);
1471                 if (ret < 0)
1472                         goto error;
1473                 return put_u64(ed, arg);
1474         }
1475         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1476         {
1477                 uint64_t cs;
1478
1479                 ret = ops->content_size(config, buf, &cs);
1480                 if (ret < 0)
1481                         goto error;
1482                 return put_u64(cs, arg);
1483         }
1484         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1485         {
1486                 uint64_t ps;
1487
1488                 ret = ops->packet_size(config, buf, &ps);
1489                 if (ret < 0)
1490                         goto error;
1491                 return put_u64(ps, arg);
1492         }
1493         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1494         {
1495                 uint64_t si;
1496
1497                 ret = ops->stream_id(config, buf, &si);
1498                 if (ret < 0)
1499                         goto error;
1500                 return put_u64(si, arg);
1501         }
1502         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1503         {
1504                 uint64_t ts;
1505
1506                 ret = ops->current_timestamp(config, buf, &ts);
1507                 if (ret < 0)
1508                         goto error;
1509                 return put_u64(ts, arg);
1510         }
1511         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1512         {
1513                 uint64_t seq;
1514
1515                 ret = ops->sequence_number(config, buf, &seq);
1516                 if (ret < 0)
1517                         goto error;
1518                 return put_u64(seq, arg);
1519         }
1520         default:
1521                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1522                                 cmd, arg);
1523         }
1524
1525 error:
1526         return -ENOSYS;
1527 }
1528
1529 #ifdef CONFIG_COMPAT
1530 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1531                 unsigned int cmd, unsigned long arg)
1532 {
1533         struct lib_ring_buffer *buf = filp->private_data;
1534         struct channel *chan = buf->backend.chan;
1535         const struct lib_ring_buffer_config *config = &chan->backend.config;
1536         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1537         int ret;
1538
1539         if (atomic_read(&chan->record_disabled))
1540                 return -EIO;
1541
1542         switch (cmd) {
1543         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1544         {
1545                 uint64_t ts;
1546
1547                 ret = ops->timestamp_begin(config, buf, &ts);
1548                 if (ret < 0)
1549                         goto error;
1550                 return put_u64(ts, arg);
1551         }
1552         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1553         {
1554                 uint64_t ts;
1555
1556                 ret = ops->timestamp_end(config, buf, &ts);
1557                 if (ret < 0)
1558                         goto error;
1559                 return put_u64(ts, arg);
1560         }
1561         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1562         {
1563                 uint64_t ed;
1564
1565                 ret = ops->events_discarded(config, buf, &ed);
1566                 if (ret < 0)
1567                         goto error;
1568                 return put_u64(ed, arg);
1569         }
1570         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1571         {
1572                 uint64_t cs;
1573
1574                 ret = ops->content_size(config, buf, &cs);
1575                 if (ret < 0)
1576                         goto error;
1577                 return put_u64(cs, arg);
1578         }
1579         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1580         {
1581                 uint64_t ps;
1582
1583                 ret = ops->packet_size(config, buf, &ps);
1584                 if (ret < 0)
1585                         goto error;
1586                 return put_u64(ps, arg);
1587         }
1588         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1589         {
1590                 uint64_t si;
1591
1592                 ret = ops->stream_id(config, buf, &si);
1593                 if (ret < 0)
1594                         goto error;
1595                 return put_u64(si, arg);
1596         }
1597         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1598         {
1599                 uint64_t ts;
1600
1601                 ret = ops->current_timestamp(config, buf, &ts);
1602                 if (ret < 0)
1603                         goto error;
1604                 return put_u64(ts, arg);
1605         }
1606         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1607         {
1608                 uint64_t seq;
1609
1610                 ret = ops->sequence_number(config, buf, &seq);
1611                 if (ret < 0)
1612                         goto error;
1613                 return put_u64(seq, arg);
1614         }
1615         default:
1616                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1617                                 cmd, arg);
1618         }
1619
1620 error:
1621         return -ENOSYS;
1622 }
1623 #endif /* CONFIG_COMPAT */
1624
1625 static void lttng_stream_override_ring_buffer_fops(void)
1626 {
1627         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1628         lttng_stream_ring_buffer_file_operations.open =
1629                 lib_ring_buffer_file_operations.open;
1630         lttng_stream_ring_buffer_file_operations.release =
1631                 lib_ring_buffer_file_operations.release;
1632         lttng_stream_ring_buffer_file_operations.poll =
1633                 lib_ring_buffer_file_operations.poll;
1634         lttng_stream_ring_buffer_file_operations.splice_read =
1635                 lib_ring_buffer_file_operations.splice_read;
1636         lttng_stream_ring_buffer_file_operations.mmap =
1637                 lib_ring_buffer_file_operations.mmap;
1638         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1639                 lttng_stream_ring_buffer_ioctl;
1640         lttng_stream_ring_buffer_file_operations.llseek =
1641                 lib_ring_buffer_file_operations.llseek;
1642 #ifdef CONFIG_COMPAT
1643         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1644                 lttng_stream_ring_buffer_compat_ioctl;
1645 #endif
1646 }
1647
1648 int __init lttng_abi_init(void)
1649 {
1650         int ret = 0;
1651
1652         wrapper_vmalloc_sync_all();
1653         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1654                                         &lttng_fops, NULL);
1655
1656         if (!lttng_proc_dentry) {
1657                 printk(KERN_ERR "Error creating LTTng control file\n");
1658                 ret = -ENOMEM;
1659                 goto error;
1660         }
1661         lttng_stream_override_ring_buffer_fops();
1662
1663 error:
1664         return ret;
1665 }
1666
1667 /* No __exit annotation because used by init error path too. */
1668 void lttng_abi_exit(void)
1669 {
1670         if (lttng_proc_dentry)
1671                 remove_proc_entry("lttng", NULL);
1672 }