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 "wrapper/kref.h"
  54 #include "lttng-abi.h"
  55 #include "lttng-abi-old.h"
  56 #include "lttng-events.h"
  57 #include "lttng-tracer.h"
  58 #include "lib/ringbuffer/frontend_types.h"
  59
  60 /*
  61  * This is LTTng's own personal way to create a system call as an external
  62  * module. We use ioctl() on /proc/lttng.
  63  */
  64
  65 static struct proc_dir_entry *lttng_proc_dentry;
  66 static const struct file_operations lttng_fops;
  67 static const struct file_operations lttng_session_fops;
  68 static const struct file_operations lttng_channel_fops;
  69 static const struct file_operations lttng_metadata_fops;
  70 static const struct file_operations lttng_event_fops;
  71 static struct file_operations lttng_stream_ring_buffer_file_operations;
  72
  73 static int put_u64(uint64_t val, unsigned long arg);
  74
  75 /*
  76  * Teardown management: opened file descriptors keep a refcount on the module,
  77  * so it can only exit when all file descriptors are closed.
  78  */
  79
  80 static
  81 int lttng_abi_create_session(void)
  82 {
  83         struct lttng_session *session;
  84         struct file *session_file;
  85         int session_fd, ret;
  86
  87         session = lttng_session_create();
  88         if (!session)
  89                 return -ENOMEM;
  90         session_fd = lttng_get_unused_fd();
  91         if (session_fd < 0) {
  92                 ret = session_fd;
  93                 goto fd_error;
  94         }
  95         session_file = anon_inode_getfile("[lttng_session]",
  96                                           &lttng_session_fops,
  97                                           session, O_RDWR);
  98         if (IS_ERR(session_file)) {
  99                 ret = PTR_ERR(session_file);
 100                 goto file_error;
 101         }
 102         session->file = session_file;
 103         fd_install(session_fd, session_file);
 104         return session_fd;
 105
 106 file_error:
 107         put_unused_fd(session_fd);
 108 fd_error:
 109         lttng_session_destroy(session);
 110         return ret;
 111 }
 112
 113 static
 114 int lttng_abi_tracepoint_list(void)
 115 {
 116         struct file *tracepoint_list_file;
 117         int file_fd, ret;
 118
 119         file_fd = lttng_get_unused_fd();
 120         if (file_fd < 0) {
 121                 ret = file_fd;
 122                 goto fd_error;
 123         }
 124
 125         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 126                                           &lttng_tracepoint_list_fops,
 127                                           NULL, O_RDWR);
 128         if (IS_ERR(tracepoint_list_file)) {
 129                 ret = PTR_ERR(tracepoint_list_file);
 130                 goto file_error;
 131         }
 132         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 133         if (ret < 0)
 134                 goto open_error;
 135         fd_install(file_fd, tracepoint_list_file);
 136         return file_fd;
 137
 138 open_error:
 139         fput(tracepoint_list_file);
 140 file_error:
 141         put_unused_fd(file_fd);
 142 fd_error:
 143         return ret;
 144 }
 145
 146 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 147 static inline
 148 int lttng_abi_syscall_list(void)
 149 {
 150         return -ENOSYS;
 151 }
 152 #else
 153 static
 154 int lttng_abi_syscall_list(void)
 155 {
 156         struct file *syscall_list_file;
 157         int file_fd, ret;
 158
 159         file_fd = lttng_get_unused_fd();
 160         if (file_fd < 0) {
 161                 ret = file_fd;
 162                 goto fd_error;
 163         }
 164
 165         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 166                                           &lttng_syscall_list_fops,
 167                                           NULL, O_RDWR);
 168         if (IS_ERR(syscall_list_file)) {
 169                 ret = PTR_ERR(syscall_list_file);
 170                 goto file_error;
 171         }
 172         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 173         if (ret < 0)
 174                 goto open_error;
 175         fd_install(file_fd, syscall_list_file);
 176         return file_fd;
 177
 178 open_error:
 179         fput(syscall_list_file);
 180 file_error:
 181         put_unused_fd(file_fd);
 182 fd_error:
 183         return ret;
 184 }
 185 #endif
 186
 187 static
 188 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 189 {
 190         v->major = LTTNG_MODULES_MAJOR_VERSION;
 191         v->minor = LTTNG_MODULES_MINOR_VERSION;
 192         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 193 }
 194
 195 static
 196 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 197 {
 198         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 199         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 200 }
 201
 202 static
 203 long lttng_abi_add_context(struct file *file,
 204         struct lttng_kernel_context *context_param,
 205         struct lttng_ctx **ctx, struct lttng_session *session)
 206 {
 207
 208         if (session->been_active)
 209                 return -EPERM;
 210
 211         switch (context_param->ctx) {
 212         case LTTNG_KERNEL_CONTEXT_PID:
 213                 return lttng_add_pid_to_ctx(ctx);
 214         case LTTNG_KERNEL_CONTEXT_PRIO:
 215                 return lttng_add_prio_to_ctx(ctx);
 216         case LTTNG_KERNEL_CONTEXT_NICE:
 217                 return lttng_add_nice_to_ctx(ctx);
 218         case LTTNG_KERNEL_CONTEXT_VPID:
 219                 return lttng_add_vpid_to_ctx(ctx);
 220         case LTTNG_KERNEL_CONTEXT_TID:
 221                 return lttng_add_tid_to_ctx(ctx);
 222         case LTTNG_KERNEL_CONTEXT_VTID:
 223                 return lttng_add_vtid_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_PPID:
 225                 return lttng_add_ppid_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_VPPID:
 227                 return lttng_add_vppid_to_ctx(ctx);
 228         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 229                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 230                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 231                                 context_param->u.perf_counter.config,
 232                                 context_param->u.perf_counter.name,
 233                                 ctx);
 234         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 235                 return lttng_add_procname_to_ctx(ctx);
 236         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 237                 return lttng_add_hostname_to_ctx(ctx);
 238         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 239                 return lttng_add_cpu_id_to_ctx(ctx);
 240         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 241                 return lttng_add_interruptible_to_ctx(ctx);
 242         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 243                 return lttng_add_need_reschedule_to_ctx(ctx);
 244         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 245                 return lttng_add_preemptible_to_ctx(ctx);
 246         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 247                 return lttng_add_migratable_to_ctx(ctx);
 248         default:
 249                 return -EINVAL;
 250         }
 251 }
 252
 253 /**
 254  *      lttng_ioctl - lttng syscall through ioctl
 255  *
 256  *      @file: the file
 257  *      @cmd: the command
 258  *      @arg: command arg
 259  *
 260  *      This ioctl implements lttng commands:
 261  *      LTTNG_KERNEL_SESSION
 262  *              Returns a LTTng trace session file descriptor
 263  *      LTTNG_KERNEL_TRACER_VERSION
 264  *              Returns the LTTng kernel tracer version
 265  *      LTTNG_KERNEL_TRACEPOINT_LIST
 266  *              Returns a file descriptor listing available tracepoints
 267  *      LTTNG_KERNEL_WAIT_QUIESCENT
 268  *              Returns after all previously running probes have completed
 269  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 270  *              Returns the LTTng kernel tracer ABI version
 271  *
 272  * The returned session will be deleted when its file descriptor is closed.
 273  */
 274 static
 275 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 276 {
 277         switch (cmd) {
 278         case LTTNG_KERNEL_OLD_SESSION:
 279         case LTTNG_KERNEL_SESSION:
 280                 return lttng_abi_create_session();
 281         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 282         {
 283                 struct lttng_kernel_tracer_version v;
 284                 struct lttng_kernel_old_tracer_version oldv;
 285                 struct lttng_kernel_old_tracer_version *uversion =
 286                         (struct lttng_kernel_old_tracer_version __user *) arg;
 287
 288                 lttng_abi_tracer_version(&v);
 289                 oldv.major = v.major;
 290                 oldv.minor = v.minor;
 291                 oldv.patchlevel = v.patchlevel;
 292
 293                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 294                         return -EFAULT;
 295                 return 0;
 296         }
 297         case LTTNG_KERNEL_TRACER_VERSION:
 298         {
 299                 struct lttng_kernel_tracer_version version;
 300                 struct lttng_kernel_tracer_version *uversion =
 301                         (struct lttng_kernel_tracer_version __user *) arg;
 302
 303                 lttng_abi_tracer_version(&version);
 304
 305                 if (copy_to_user(uversion, &version, sizeof(version)))
 306                         return -EFAULT;
 307                 return 0;
 308         }
 309         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 310         {
 311                 struct lttng_kernel_tracer_abi_version version;
 312                 struct lttng_kernel_tracer_abi_version *uversion =
 313                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 314
 315                 lttng_abi_tracer_abi_version(&version);
 316
 317                 if (copy_to_user(uversion, &version, sizeof(version)))
 318                         return -EFAULT;
 319                 return 0;
 320         }
 321         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 322         case LTTNG_KERNEL_TRACEPOINT_LIST:
 323                 return lttng_abi_tracepoint_list();
 324         case LTTNG_KERNEL_SYSCALL_LIST:
 325                 return lttng_abi_syscall_list();
 326         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 327         case LTTNG_KERNEL_WAIT_QUIESCENT:
 328                 synchronize_trace();
 329                 return 0;
 330         case LTTNG_KERNEL_OLD_CALIBRATE:
 331         {
 332                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 333                         (struct lttng_kernel_old_calibrate __user *) arg;
 334                 struct lttng_kernel_old_calibrate old_calibrate;
 335                 struct lttng_kernel_calibrate calibrate;
 336                 int ret;
 337
 338                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 339                         return -EFAULT;
 340                 calibrate.type = old_calibrate.type;
 341                 ret = lttng_calibrate(&calibrate);
 342                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 343                         return -EFAULT;
 344                 return ret;
 345         }
 346         case LTTNG_KERNEL_CALIBRATE:
 347         {
 348                 struct lttng_kernel_calibrate __user *ucalibrate =
 349                         (struct lttng_kernel_calibrate __user *) arg;
 350                 struct lttng_kernel_calibrate calibrate;
 351                 int ret;
 352
 353                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 354                         return -EFAULT;
 355                 ret = lttng_calibrate(&calibrate);
 356                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 357                         return -EFAULT;
 358                 return ret;
 359         }
 360         default:
 361                 return -ENOIOCTLCMD;
 362         }
 363 }
 364
 365 static const struct file_operations lttng_fops = {
 366         .owner = THIS_MODULE,
 367         .unlocked_ioctl = lttng_ioctl,
 368 #ifdef CONFIG_COMPAT
 369         .compat_ioctl = lttng_ioctl,
 370 #endif
 371 };
 372
 373 static
 374 int lttng_abi_create_channel(struct file *session_file,
 375                              struct lttng_kernel_channel *chan_param,
 376                              enum channel_type channel_type)
 377 {
 378         struct lttng_session *session = session_file->private_data;
 379         const struct file_operations *fops = NULL;
 380         const char *transport_name;
 381         struct lttng_channel *chan;
 382         struct file *chan_file;
 383         int chan_fd;
 384         int ret = 0;
 385
 386         chan_fd = lttng_get_unused_fd();
 387         if (chan_fd < 0) {
 388                 ret = chan_fd;
 389                 goto fd_error;
 390         }
 391         switch (channel_type) {
 392         case PER_CPU_CHANNEL:
 393                 fops = &lttng_channel_fops;
 394                 break;
 395         case METADATA_CHANNEL:
 396                 fops = &lttng_metadata_fops;
 397                 break;
 398         }
 399
 400         chan_file = anon_inode_getfile("[lttng_channel]",
 401                                        fops,
 402                                        NULL, O_RDWR);
 403         if (IS_ERR(chan_file)) {
 404                 ret = PTR_ERR(chan_file);
 405                 goto file_error;
 406         }
 407         switch (channel_type) {
 408         case PER_CPU_CHANNEL:
 409                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 410                         transport_name = chan_param->overwrite ?
 411                                 "relay-overwrite" : "relay-discard";
 412                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 413                         transport_name = chan_param->overwrite ?
 414                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 415                 } else {
 416                         return -EINVAL;
 417                 }
 418                 break;
 419         case METADATA_CHANNEL:
 420                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 421                         transport_name = "relay-metadata";
 422                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 423                         transport_name = "relay-metadata-mmap";
 424                 else
 425                         return -EINVAL;
 426                 break;
 427         default:
 428                 transport_name = "<unknown>";
 429                 break;
 430         }
 431         if (atomic_long_add_unless(&session_file->f_count,
 432                 1, INT_MAX) == INT_MAX) {
 433                 goto refcount_error;
 434         }
 435         /*
 436          * We tolerate no failure path after channel creation. It will stay
 437          * invariant for the rest of the session.
 438          */
 439         chan = lttng_channel_create(session, transport_name, NULL,
 440                                   chan_param->subbuf_size,
 441                                   chan_param->num_subbuf,
 442                                   chan_param->switch_timer_interval,
 443                                   chan_param->read_timer_interval,
 444                                   channel_type);
 445         if (!chan) {
 446                 ret = -EINVAL;
 447                 goto chan_error;
 448         }
 449         chan->file = chan_file;
 450         chan_file->private_data = chan;
 451         fd_install(chan_fd, chan_file);
 452
 453         return chan_fd;
 454
 455 chan_error:
 456         atomic_long_dec(&session_file->f_count);
 457 refcount_error:
 458         fput(chan_file);
 459 file_error:
 460         put_unused_fd(chan_fd);
 461 fd_error:
 462         return ret;
 463 }
 464
 465 /**
 466  *      lttng_session_ioctl - lttng session fd ioctl
 467  *
 468  *      @file: the file
 469  *      @cmd: the command
 470  *      @arg: command arg
 471  *
 472  *      This ioctl implements lttng commands:
 473  *      LTTNG_KERNEL_CHANNEL
 474  *              Returns a LTTng channel file descriptor
 475  *      LTTNG_KERNEL_ENABLE
 476  *              Enables tracing for a session (weak enable)
 477  *      LTTNG_KERNEL_DISABLE
 478  *              Disables tracing for a session (strong disable)
 479  *      LTTNG_KERNEL_METADATA
 480  *              Returns a LTTng metadata file descriptor
 481  *      LTTNG_KERNEL_SESSION_TRACK_PID
 482  *              Add PID to session tracker
 483  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 484  *              Remove PID from session tracker
 485  *
 486  * The returned channel will be deleted when its file descriptor is closed.
 487  */
 488 static
 489 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 490 {
 491         struct lttng_session *session = file->private_data;
 492
 493         switch (cmd) {
 494         case LTTNG_KERNEL_OLD_CHANNEL:
 495         {
 496                 struct lttng_kernel_channel chan_param;
 497                 struct lttng_kernel_old_channel old_chan_param;
 498
 499                 if (copy_from_user(&old_chan_param,
 500                                 (struct lttng_kernel_old_channel __user *) arg,
 501                                 sizeof(struct lttng_kernel_old_channel)))
 502                         return -EFAULT;
 503                 chan_param.overwrite = old_chan_param.overwrite;
 504                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 505                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 506                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 507                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 508                 chan_param.output = old_chan_param.output;
 509
 510                 return lttng_abi_create_channel(file, &chan_param,
 511                                 PER_CPU_CHANNEL);
 512         }
 513         case LTTNG_KERNEL_CHANNEL:
 514         {
 515                 struct lttng_kernel_channel chan_param;
 516
 517                 if (copy_from_user(&chan_param,
 518                                 (struct lttng_kernel_channel __user *) arg,
 519                                 sizeof(struct lttng_kernel_channel)))
 520                         return -EFAULT;
 521                 return lttng_abi_create_channel(file, &chan_param,
 522                                 PER_CPU_CHANNEL);
 523         }
 524         case LTTNG_KERNEL_OLD_SESSION_START:
 525         case LTTNG_KERNEL_OLD_ENABLE:
 526         case LTTNG_KERNEL_SESSION_START:
 527         case LTTNG_KERNEL_ENABLE:
 528                 return lttng_session_enable(session);
 529         case LTTNG_KERNEL_OLD_SESSION_STOP:
 530         case LTTNG_KERNEL_OLD_DISABLE:
 531         case LTTNG_KERNEL_SESSION_STOP:
 532         case LTTNG_KERNEL_DISABLE:
 533                 return lttng_session_disable(session);
 534         case LTTNG_KERNEL_OLD_METADATA:
 535         {
 536                 struct lttng_kernel_channel chan_param;
 537                 struct lttng_kernel_old_channel old_chan_param;
 538
 539                 if (copy_from_user(&old_chan_param,
 540                                 (struct lttng_kernel_old_channel __user *) arg,
 541                                 sizeof(struct lttng_kernel_old_channel)))
 542                         return -EFAULT;
 543                 chan_param.overwrite = old_chan_param.overwrite;
 544                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 545                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 546                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 547                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 548                 chan_param.output = old_chan_param.output;
 549
 550                 return lttng_abi_create_channel(file, &chan_param,
 551                                 METADATA_CHANNEL);
 552         }
 553         case LTTNG_KERNEL_METADATA:
 554         {
 555                 struct lttng_kernel_channel chan_param;
 556
 557                 if (copy_from_user(&chan_param,
 558                                         (struct lttng_kernel_channel __user *) arg,
 559                                         sizeof(struct lttng_kernel_channel)))
 560                         return -EFAULT;
 561                 return lttng_abi_create_channel(file, &chan_param,
 562                                 METADATA_CHANNEL);
 563         }
 564         case LTTNG_KERNEL_SESSION_TRACK_PID:
 565                 return lttng_session_track_pid(session, (int) arg);
 566         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 567                 return lttng_session_untrack_pid(session, (int) arg);
 568         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 569                 return lttng_session_list_tracker_pids(session);
 570         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 571                 return lttng_session_metadata_regenerate(session);
 572         default:
 573                 return -ENOIOCTLCMD;
 574         }
 575 }
 576
 577 /*
 578  * Called when the last file reference is dropped.
 579  *
 580  * Big fat note: channels and events are invariant for the whole session after
 581  * their creation. So this session destruction also destroys all channel and
 582  * event structures specific to this session (they are not destroyed when their
 583  * individual file is released).
 584  */
 585 static
 586 int lttng_session_release(struct inode *inode, struct file *file)
 587 {
 588         struct lttng_session *session = file->private_data;
 589
 590         if (session)
 591                 lttng_session_destroy(session);
 592         return 0;
 593 }
 594
 595 static const struct file_operations lttng_session_fops = {
 596         .owner = THIS_MODULE,
 597         .release = lttng_session_release,
 598         .unlocked_ioctl = lttng_session_ioctl,
 599 #ifdef CONFIG_COMPAT
 600         .compat_ioctl = lttng_session_ioctl,
 601 #endif
 602 };
 603
 604 /**
 605  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 606  *      @filp: the file
 607  *      @wait: poll table
 608  *
 609  *      Handles the poll operations for the metadata channels.
 610  */
 611 static
 612 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 613                 poll_table *wait)
 614 {
 615         struct lttng_metadata_stream *stream = filp->private_data;
 616         struct lib_ring_buffer *buf = stream->priv;
 617         int finalized;
 618         unsigned int mask = 0;
 619
 620         if (filp->f_mode & FMODE_READ) {
 621                 poll_wait_set_exclusive(wait);
 622                 poll_wait(filp, &stream->read_wait, wait);
 623
 624                 finalized = stream->finalized;
 625
 626                 /*
 627                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 628                  * ordering finalized load before offsets loads.
 629                  */
 630                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 631
 632                 if (finalized)
 633                         mask |= POLLHUP;
 634
 635                 mutex_lock(&stream->metadata_cache->lock);
 636                 if (stream->metadata_cache->metadata_written >
 637                                 stream->metadata_out)
 638                         mask |= POLLIN;
 639                 mutex_unlock(&stream->metadata_cache->lock);
 640         }
 641
 642         return mask;
 643 }
 644
 645 static
 646 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 647                 unsigned int cmd, unsigned long arg)
 648 {
 649         struct lttng_metadata_stream *stream = filp->private_data;
 650
 651         stream->metadata_out = stream->metadata_in;
 652 }
 653
 654 static
 655 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 656                 unsigned int cmd, unsigned long arg)
 657 {
 658         int ret;
 659         struct lttng_metadata_stream *stream = filp->private_data;
 660         struct lib_ring_buffer *buf = stream->priv;
 661
 662         switch (cmd) {
 663         case RING_BUFFER_GET_NEXT_SUBBUF:
 664         {
 665                 struct lttng_metadata_stream *stream = filp->private_data;
 666                 struct lib_ring_buffer *buf = stream->priv;
 667                 struct channel *chan = buf->backend.chan;
 668
 669                 ret = lttng_metadata_output_channel(stream, chan);
 670                 if (ret > 0) {
 671                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 672                         ret = 0;
 673                 } else if (ret < 0)
 674                         goto err;
 675                 break;
 676         }
 677         case RING_BUFFER_GET_SUBBUF:
 678         {
 679                 /*
 680                  * Random access is not allowed for metadata channel.
 681                  */
 682                 return -ENOSYS;
 683         }
 684         case RING_BUFFER_FLUSH:
 685         {
 686                 struct lttng_metadata_stream *stream = filp->private_data;
 687                 struct lib_ring_buffer *buf = stream->priv;
 688                 struct channel *chan = buf->backend.chan;
 689
 690                 /*
 691                  * Before doing the actual ring buffer flush, write up to one
 692                  * packet of metadata in the ring buffer.
 693                  */
 694                 ret = lttng_metadata_output_channel(stream, chan);
 695                 if (ret < 0)
 696                         goto err;
 697                 break;
 698         }
 699         case RING_BUFFER_GET_METADATA_VERSION:
 700         {
 701                 struct lttng_metadata_stream *stream = filp->private_data;
 702
 703                 return put_u64(stream->version, arg);
 704         }
 705         default:
 706                 break;
 707         }
 708         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 709
 710         /* Performing lib ring buffer ioctl after our own. */
 711         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 712         if (ret < 0)
 713                 goto err;
 714
 715         switch (cmd) {
 716         case RING_BUFFER_PUT_NEXT_SUBBUF:
 717         {
 718                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 719                                 cmd, arg);
 720                 break;
 721         }
 722         default:
 723                 break;
 724         }
 725 err:
 726         return ret;
 727 }
 728
 729 #ifdef CONFIG_COMPAT
 730 static
 731 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 732                 unsigned int cmd, unsigned long arg)
 733 {
 734         int ret;
 735         struct lttng_metadata_stream *stream = filp->private_data;
 736         struct lib_ring_buffer *buf = stream->priv;
 737
 738         switch (cmd) {
 739         case RING_BUFFER_GET_NEXT_SUBBUF:
 740         {
 741                 struct lttng_metadata_stream *stream = filp->private_data;
 742                 struct lib_ring_buffer *buf = stream->priv;
 743                 struct channel *chan = buf->backend.chan;
 744
 745                 ret = lttng_metadata_output_channel(stream, chan);
 746                 if (ret > 0) {
 747                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 748                         ret = 0;
 749                 } else if (ret < 0)
 750                         goto err;
 751                 break;
 752         }
 753         case RING_BUFFER_GET_SUBBUF:
 754         {
 755                 /*
 756                  * Random access is not allowed for metadata channel.
 757                  */
 758                 return -ENOSYS;
 759         }
 760         default:
 761                 break;
 762         }
 763         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 764
 765         /* Performing lib ring buffer ioctl after our own. */
 766         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 767         if (ret < 0)
 768                 goto err;
 769
 770         switch (cmd) {
 771         case RING_BUFFER_PUT_NEXT_SUBBUF:
 772         {
 773                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 774                                 cmd, arg);
 775                 break;
 776         }
 777         case RING_BUFFER_GET_METADATA_VERSION:
 778         {
 779                 struct lttng_metadata_stream *stream = filp->private_data;
 780
 781                 return put_u64(stream->version, arg);
 782         }
 783         default:
 784                 break;
 785         }
 786 err:
 787         return ret;
 788 }
 789 #endif
 790
 791 /*
 792  * This is not used by anonymous file descriptors. This code is left
 793  * there if we ever want to implement an inode with open() operation.
 794  */
 795 static
 796 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 797 {
 798         struct lttng_metadata_stream *stream = inode->i_private;
 799         struct lib_ring_buffer *buf = stream->priv;
 800
 801         file->private_data = buf;
 802         /*
 803          * Since life-time of metadata cache differs from that of
 804          * session, we need to keep our own reference on the transport.
 805          */
 806         if (!try_module_get(stream->transport->owner)) {
 807                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 808                 return -EBUSY;
 809         }
 810         return lib_ring_buffer_open(inode, file, buf);
 811 }
 812
 813 static
 814 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 815 {
 816         struct lttng_metadata_stream *stream = file->private_data;
 817         struct lib_ring_buffer *buf = stream->priv;
 818
 819         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 820         module_put(stream->transport->owner);
 821         return lib_ring_buffer_release(inode, file, buf);
 822 }
 823
 824 static
 825 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 826                 struct pipe_inode_info *pipe, size_t len,
 827                 unsigned int flags)
 828 {
 829         struct lttng_metadata_stream *stream = in->private_data;
 830         struct lib_ring_buffer *buf = stream->priv;
 831
 832         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 833                         flags, buf);
 834 }
 835
 836 static
 837 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 838                 struct vm_area_struct *vma)
 839 {
 840         struct lttng_metadata_stream *stream = filp->private_data;
 841         struct lib_ring_buffer *buf = stream->priv;
 842
 843         return lib_ring_buffer_mmap(filp, vma, buf);
 844 }
 845
 846 static
 847 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 848         .owner = THIS_MODULE,
 849         .open = lttng_metadata_ring_buffer_open,
 850         .release = lttng_metadata_ring_buffer_release,
 851         .poll = lttng_metadata_ring_buffer_poll,
 852         .splice_read = lttng_metadata_ring_buffer_splice_read,
 853         .mmap = lttng_metadata_ring_buffer_mmap,
 854         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 855         .llseek = vfs_lib_ring_buffer_no_llseek,
 856 #ifdef CONFIG_COMPAT
 857         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 858 #endif
 859 };
 860
 861 static
 862 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 863                 const struct file_operations *fops)
 864 {
 865         int stream_fd, ret;
 866         struct file *stream_file;
 867
 868         stream_fd = lttng_get_unused_fd();
 869         if (stream_fd < 0) {
 870                 ret = stream_fd;
 871                 goto fd_error;
 872         }
 873         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 874                         stream_priv, O_RDWR);
 875         if (IS_ERR(stream_file)) {
 876                 ret = PTR_ERR(stream_file);
 877                 goto file_error;
 878         }
 879         /*
 880          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 881          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 882          * file descriptor, so we set FMODE_PREAD here.
 883          */
 884         stream_file->f_mode |= FMODE_PREAD;
 885         fd_install(stream_fd, stream_file);
 886         /*
 887          * The stream holds a reference to the channel within the generic ring
 888          * buffer library, so no need to hold a refcount on the channel and
 889          * session files here.
 890          */
 891         return stream_fd;
 892
 893 file_error:
 894         put_unused_fd(stream_fd);
 895 fd_error:
 896         return ret;
 897 }
 898
 899 static
 900 int lttng_abi_open_stream(struct file *channel_file)
 901 {
 902         struct lttng_channel *channel = channel_file->private_data;
 903         struct lib_ring_buffer *buf;
 904         int ret;
 905         void *stream_priv;
 906
 907         buf = channel->ops->buffer_read_open(channel->chan);
 908         if (!buf)
 909                 return -ENOENT;
 910
 911         stream_priv = buf;
 912         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 913                         &lttng_stream_ring_buffer_file_operations);
 914         if (ret < 0)
 915                 goto fd_error;
 916
 917         return ret;
 918
 919 fd_error:
 920         channel->ops->buffer_read_close(buf);
 921         return ret;
 922 }
 923
 924 static
 925 int lttng_abi_open_metadata_stream(struct file *channel_file)
 926 {
 927         struct lttng_channel *channel = channel_file->private_data;
 928         struct lttng_session *session = channel->session;
 929         struct lib_ring_buffer *buf;
 930         int ret;
 931         struct lttng_metadata_stream *metadata_stream;
 932         void *stream_priv;
 933
 934         buf = channel->ops->buffer_read_open(channel->chan);
 935         if (!buf)
 936                 return -ENOENT;
 937
 938         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 939                         GFP_KERNEL);
 940         if (!metadata_stream) {
 941                 ret = -ENOMEM;
 942                 goto nomem;
 943         }
 944         metadata_stream->metadata_cache = session->metadata_cache;
 945         init_waitqueue_head(&metadata_stream->read_wait);
 946         metadata_stream->priv = buf;
 947         stream_priv = metadata_stream;
 948         metadata_stream->transport = channel->transport;
 949
 950         /*
 951          * Since life-time of metadata cache differs from that of
 952          * session, we need to keep our own reference on the transport.
 953          */
 954         if (!try_module_get(metadata_stream->transport->owner)) {
 955                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 956                 ret = -EINVAL;
 957                 goto notransport;
 958         }
 959
 960         if (!lttng_kref_get(&session->metadata_cache->refcount))
 961                 goto kref_error;
 962         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 963                         &lttng_metadata_ring_buffer_file_operations);
 964         if (ret < 0)
 965                 goto fd_error;
 966
 967         list_add(&metadata_stream->list,
 968                 &session->metadata_cache->metadata_stream);
 969         return ret;
 970
 971 fd_error:
 972         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
 973 kref_error:
 974         module_put(metadata_stream->transport->owner);
 975 notransport:
 976         kfree(metadata_stream);
 977 nomem:
 978         channel->ops->buffer_read_close(buf);
 979         return ret;
 980 }
 981
 982 static
 983 int lttng_abi_create_event(struct file *channel_file,
 984                            struct lttng_kernel_event *event_param)
 985 {
 986         struct lttng_channel *channel = channel_file->private_data;
 987         int event_fd, ret;
 988         struct file *event_file;
 989         void *priv;
 990
 991         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 992         switch (event_param->instrumentation) {
 993         case LTTNG_KERNEL_KRETPROBE:
 994                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 995                 break;
 996         case LTTNG_KERNEL_KPROBE:
 997                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 998                 break;
 999         case LTTNG_KERNEL_FUNCTION:
1000                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1001                 break;
1002         default:
1003                 break;
1004         }
1005         event_fd = lttng_get_unused_fd();
1006         if (event_fd < 0) {
1007                 ret = event_fd;
1008                 goto fd_error;
1009         }
1010         event_file = anon_inode_getfile("[lttng_event]",
1011                                         &lttng_event_fops,
1012                                         NULL, O_RDWR);
1013         if (IS_ERR(event_file)) {
1014                 ret = PTR_ERR(event_file);
1015                 goto file_error;
1016         }
1017         /* The event holds a reference on the channel */
1018         if (atomic_long_add_unless(&channel_file->f_count,
1019                 1, INT_MAX) == INT_MAX) {
1020                 goto refcount_error;
1021         }
1022         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1023                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1024                 struct lttng_enabler *enabler;
1025
1026                 if (event_param->name[strlen(event_param->name) - 1] == '*') {
1027                         enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
1028                                 event_param, channel);
1029                 } else {
1030                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1031                                 event_param, channel);
1032                 }
1033                 priv = enabler;
1034         } else {
1035                 struct lttng_event *event;
1036
1037                 /*
1038                  * We tolerate no failure path after event creation. It
1039                  * will stay invariant for the rest of the session.
1040                  */
1041                 event = lttng_event_create(channel, event_param,
1042                                 NULL, NULL,
1043                                 event_param->instrumentation);
1044                 WARN_ON_ONCE(!event);
1045                 if (IS_ERR(event)) {
1046                         ret = PTR_ERR(event);
1047                         goto event_error;
1048                 }
1049                 priv = event;
1050         }
1051         event_file->private_data = priv;
1052         fd_install(event_fd, event_file);
1053         return event_fd;
1054
1055 event_error:
1056         atomic_long_dec(&channel_file->f_count);
1057 refcount_error:
1058         fput(event_file);
1059 file_error:
1060         put_unused_fd(event_fd);
1061 fd_error:
1062         return ret;
1063 }
1064
1065 /**
1066  *      lttng_channel_ioctl - lttng syscall through ioctl
1067  *
1068  *      @file: the file
1069  *      @cmd: the command
1070  *      @arg: command arg
1071  *
1072  *      This ioctl implements lttng commands:
1073  *      LTTNG_KERNEL_STREAM
1074  *              Returns an event stream file descriptor or failure.
1075  *              (typically, one event stream records events from one CPU)
1076  *      LTTNG_KERNEL_EVENT
1077  *              Returns an event file descriptor or failure.
1078  *      LTTNG_KERNEL_CONTEXT
1079  *              Prepend a context field to each event in the channel
1080  *      LTTNG_KERNEL_ENABLE
1081  *              Enable recording for events in this channel (weak enable)
1082  *      LTTNG_KERNEL_DISABLE
1083  *              Disable recording for events in this channel (strong disable)
1084  *
1085  * Channel and event file descriptors also hold a reference on the session.
1086  */
1087 static
1088 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1089 {
1090         struct lttng_channel *channel = file->private_data;
1091
1092         switch (cmd) {
1093         case LTTNG_KERNEL_OLD_STREAM:
1094         case LTTNG_KERNEL_STREAM:
1095                 return lttng_abi_open_stream(file);
1096         case LTTNG_KERNEL_OLD_EVENT:
1097         {
1098                 struct lttng_kernel_event *uevent_param;
1099                 struct lttng_kernel_old_event *old_uevent_param;
1100                 int ret;
1101
1102                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1103                                 GFP_KERNEL);
1104                 if (!uevent_param) {
1105                         ret = -ENOMEM;
1106                         goto old_event_end;
1107                 }
1108                 old_uevent_param = kmalloc(
1109                                 sizeof(struct lttng_kernel_old_event),
1110                                 GFP_KERNEL);
1111                 if (!old_uevent_param) {
1112                         ret = -ENOMEM;
1113                         goto old_event_error_free_param;
1114                 }
1115                 if (copy_from_user(old_uevent_param,
1116                                 (struct lttng_kernel_old_event __user *) arg,
1117                                 sizeof(struct lttng_kernel_old_event))) {
1118                         ret = -EFAULT;
1119                         goto old_event_error_free_old_param;
1120                 }
1121
1122                 memcpy(uevent_param->name, old_uevent_param->name,
1123                                 sizeof(uevent_param->name));
1124                 uevent_param->instrumentation =
1125                         old_uevent_param->instrumentation;
1126
1127                 switch (old_uevent_param->instrumentation) {
1128                 case LTTNG_KERNEL_KPROBE:
1129                         uevent_param->u.kprobe.addr =
1130                                 old_uevent_param->u.kprobe.addr;
1131                         uevent_param->u.kprobe.offset =
1132                                 old_uevent_param->u.kprobe.offset;
1133                         memcpy(uevent_param->u.kprobe.symbol_name,
1134                                 old_uevent_param->u.kprobe.symbol_name,
1135                                 sizeof(uevent_param->u.kprobe.symbol_name));
1136                         break;
1137                 case LTTNG_KERNEL_KRETPROBE:
1138                         uevent_param->u.kretprobe.addr =
1139                                 old_uevent_param->u.kretprobe.addr;
1140                         uevent_param->u.kretprobe.offset =
1141                                 old_uevent_param->u.kretprobe.offset;
1142                         memcpy(uevent_param->u.kretprobe.symbol_name,
1143                                 old_uevent_param->u.kretprobe.symbol_name,
1144                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1145                         break;
1146                 case LTTNG_KERNEL_FUNCTION:
1147                         memcpy(uevent_param->u.ftrace.symbol_name,
1148                                         old_uevent_param->u.ftrace.symbol_name,
1149                                         sizeof(uevent_param->u.ftrace.symbol_name));
1150                         break;
1151                 default:
1152                         break;
1153                 }
1154                 ret = lttng_abi_create_event(file, uevent_param);
1155
1156 old_event_error_free_old_param:
1157                 kfree(old_uevent_param);
1158 old_event_error_free_param:
1159                 kfree(uevent_param);
1160 old_event_end:
1161                 return ret;
1162         }
1163         case LTTNG_KERNEL_EVENT:
1164         {
1165                 struct lttng_kernel_event uevent_param;
1166
1167                 if (copy_from_user(&uevent_param,
1168                                 (struct lttng_kernel_event __user *) arg,
1169                                 sizeof(uevent_param)))
1170                         return -EFAULT;
1171                 return lttng_abi_create_event(file, &uevent_param);
1172         }
1173         case LTTNG_KERNEL_OLD_CONTEXT:
1174         {
1175                 struct lttng_kernel_context *ucontext_param;
1176                 struct lttng_kernel_old_context *old_ucontext_param;
1177                 int ret;
1178
1179                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1180                                 GFP_KERNEL);
1181                 if (!ucontext_param) {
1182                         ret = -ENOMEM;
1183                         goto old_ctx_end;
1184                 }
1185                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1186                                 GFP_KERNEL);
1187                 if (!old_ucontext_param) {
1188                         ret = -ENOMEM;
1189                         goto old_ctx_error_free_param;
1190                 }
1191
1192                 if (copy_from_user(old_ucontext_param,
1193                                 (struct lttng_kernel_old_context __user *) arg,
1194                                 sizeof(struct lttng_kernel_old_context))) {
1195                         ret = -EFAULT;
1196                         goto old_ctx_error_free_old_param;
1197                 }
1198                 ucontext_param->ctx = old_ucontext_param->ctx;
1199                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1200                                 sizeof(ucontext_param->padding));
1201                 /* only type that uses the union */
1202                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1203                         ucontext_param->u.perf_counter.type =
1204                                 old_ucontext_param->u.perf_counter.type;
1205                         ucontext_param->u.perf_counter.config =
1206                                 old_ucontext_param->u.perf_counter.config;
1207                         memcpy(ucontext_param->u.perf_counter.name,
1208                                 old_ucontext_param->u.perf_counter.name,
1209                                 sizeof(ucontext_param->u.perf_counter.name));
1210                 }
1211
1212                 ret = lttng_abi_add_context(file,
1213                                 ucontext_param,
1214                                 &channel->ctx, channel->session);
1215
1216 old_ctx_error_free_old_param:
1217                 kfree(old_ucontext_param);
1218 old_ctx_error_free_param:
1219                 kfree(ucontext_param);
1220 old_ctx_end:
1221                 return ret;
1222         }
1223         case LTTNG_KERNEL_CONTEXT:
1224         {
1225                 struct lttng_kernel_context ucontext_param;
1226
1227                 if (copy_from_user(&ucontext_param,
1228                                 (struct lttng_kernel_context __user *) arg,
1229                                 sizeof(ucontext_param)))
1230                         return -EFAULT;
1231                 return lttng_abi_add_context(file,
1232                                 &ucontext_param,
1233                                 &channel->ctx, channel->session);
1234         }
1235         case LTTNG_KERNEL_OLD_ENABLE:
1236         case LTTNG_KERNEL_ENABLE:
1237                 return lttng_channel_enable(channel);
1238         case LTTNG_KERNEL_OLD_DISABLE:
1239         case LTTNG_KERNEL_DISABLE:
1240                 return lttng_channel_disable(channel);
1241         case LTTNG_KERNEL_SYSCALL_MASK:
1242                 return lttng_channel_syscall_mask(channel,
1243                         (struct lttng_kernel_syscall_mask __user *) arg);
1244         default:
1245                 return -ENOIOCTLCMD;
1246         }
1247
1248 }
1249
1250 /**
1251  *      lttng_metadata_ioctl - lttng syscall through ioctl
1252  *
1253  *      @file: the file
1254  *      @cmd: the command
1255  *      @arg: command arg
1256  *
1257  *      This ioctl implements lttng commands:
1258  *      LTTNG_KERNEL_STREAM
1259  *              Returns an event stream file descriptor or failure.
1260  *
1261  * Channel and event file descriptors also hold a reference on the session.
1262  */
1263 static
1264 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1265 {
1266         switch (cmd) {
1267         case LTTNG_KERNEL_OLD_STREAM:
1268         case LTTNG_KERNEL_STREAM:
1269                 return lttng_abi_open_metadata_stream(file);
1270         default:
1271                 return -ENOIOCTLCMD;
1272         }
1273 }
1274
1275 /**
1276  *      lttng_channel_poll - lttng stream addition/removal monitoring
1277  *
1278  *      @file: the file
1279  *      @wait: poll table
1280  */
1281 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1282 {
1283         struct lttng_channel *channel = file->private_data;
1284         unsigned int mask = 0;
1285
1286         if (file->f_mode & FMODE_READ) {
1287                 poll_wait_set_exclusive(wait);
1288                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1289                           wait);
1290
1291                 if (channel->ops->is_disabled(channel->chan))
1292                         return POLLERR;
1293                 if (channel->ops->is_finalized(channel->chan))
1294                         return POLLHUP;
1295                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1296                         return POLLIN | POLLRDNORM;
1297                 return 0;
1298         }
1299         return mask;
1300
1301 }
1302
1303 static
1304 int lttng_channel_release(struct inode *inode, struct file *file)
1305 {
1306         struct lttng_channel *channel = file->private_data;
1307
1308         if (channel)
1309                 fput(channel->session->file);
1310         return 0;
1311 }
1312
1313 static
1314 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1315 {
1316         struct lttng_channel *channel = file->private_data;
1317
1318         if (channel) {
1319                 fput(channel->session->file);
1320                 lttng_metadata_channel_destroy(channel);
1321         }
1322
1323         return 0;
1324 }
1325
1326 static const struct file_operations lttng_channel_fops = {
1327         .owner = THIS_MODULE,
1328         .release = lttng_channel_release,
1329         .poll = lttng_channel_poll,
1330         .unlocked_ioctl = lttng_channel_ioctl,
1331 #ifdef CONFIG_COMPAT
1332         .compat_ioctl = lttng_channel_ioctl,
1333 #endif
1334 };
1335
1336 static const struct file_operations lttng_metadata_fops = {
1337         .owner = THIS_MODULE,
1338         .release = lttng_metadata_channel_release,
1339         .unlocked_ioctl = lttng_metadata_ioctl,
1340 #ifdef CONFIG_COMPAT
1341         .compat_ioctl = lttng_metadata_ioctl,
1342 #endif
1343 };
1344
1345 /**
1346  *      lttng_event_ioctl - lttng syscall through ioctl
1347  *
1348  *      @file: the file
1349  *      @cmd: the command
1350  *      @arg: command arg
1351  *
1352  *      This ioctl implements lttng commands:
1353  *      LTTNG_KERNEL_CONTEXT
1354  *              Prepend a context field to each record of this event
1355  *      LTTNG_KERNEL_ENABLE
1356  *              Enable recording for this event (weak enable)
1357  *      LTTNG_KERNEL_DISABLE
1358  *              Disable recording for this event (strong disable)
1359  */
1360 static
1361 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1362 {
1363         struct lttng_event *event;
1364         struct lttng_enabler *enabler;
1365         enum lttng_event_type *evtype = file->private_data;
1366
1367         switch (cmd) {
1368         case LTTNG_KERNEL_OLD_CONTEXT:
1369         {
1370                 /* Not implemented */
1371                 return -ENOSYS;
1372         }
1373         case LTTNG_KERNEL_CONTEXT:
1374         {
1375                 /* Not implemented */
1376                 return -ENOSYS;
1377         }
1378         case LTTNG_KERNEL_OLD_ENABLE:
1379         case LTTNG_KERNEL_ENABLE:
1380                 switch (*evtype) {
1381                 case LTTNG_TYPE_EVENT:
1382                         event = file->private_data;
1383                         return lttng_event_enable(event);
1384                 case LTTNG_TYPE_ENABLER:
1385                         enabler = file->private_data;
1386                         return lttng_enabler_enable(enabler);
1387                 default:
1388                         WARN_ON_ONCE(1);
1389                         return -ENOSYS;
1390                 }
1391         case LTTNG_KERNEL_OLD_DISABLE:
1392         case LTTNG_KERNEL_DISABLE:
1393                 switch (*evtype) {
1394                 case LTTNG_TYPE_EVENT:
1395                         event = file->private_data;
1396                         return lttng_event_disable(event);
1397                 case LTTNG_TYPE_ENABLER:
1398                         enabler = file->private_data;
1399                         return lttng_enabler_disable(enabler);
1400                 default:
1401                         WARN_ON_ONCE(1);
1402                         return -ENOSYS;
1403                 }
1404         case LTTNG_KERNEL_FILTER:
1405                 switch (*evtype) {
1406                 case LTTNG_TYPE_EVENT:
1407                         return -EINVAL;
1408                 case LTTNG_TYPE_ENABLER:
1409                 {
1410                         enabler = file->private_data;
1411                         return lttng_enabler_attach_bytecode(enabler,
1412                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1413                 }
1414
1415                 }
1416         default:
1417                 return -ENOIOCTLCMD;
1418         }
1419 }
1420
1421 static
1422 int lttng_event_release(struct inode *inode, struct file *file)
1423 {
1424         struct lttng_event *event;
1425         struct lttng_enabler *enabler;
1426         enum lttng_event_type *evtype = file->private_data;
1427
1428         if (!evtype)
1429                 return 0;
1430
1431         switch (*evtype) {
1432         case LTTNG_TYPE_EVENT:
1433                 event = file->private_data;
1434                 if (event)
1435                         fput(event->chan->file);
1436                 break;
1437         case LTTNG_TYPE_ENABLER:
1438                 enabler = file->private_data;
1439                 if (enabler)
1440                         fput(enabler->chan->file);
1441                 break;
1442         default:
1443                 WARN_ON_ONCE(1);
1444                 break;
1445         }
1446
1447         return 0;
1448 }
1449
1450 /* TODO: filter control ioctl */
1451 static const struct file_operations lttng_event_fops = {
1452         .owner = THIS_MODULE,
1453         .release = lttng_event_release,
1454         .unlocked_ioctl = lttng_event_ioctl,
1455 #ifdef CONFIG_COMPAT
1456         .compat_ioctl = lttng_event_ioctl,
1457 #endif
1458 };
1459
1460 static int put_u64(uint64_t val, unsigned long arg)
1461 {
1462         return put_user(val, (uint64_t __user *) arg);
1463 }
1464
1465 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1466                 unsigned int cmd, unsigned long arg)
1467 {
1468         struct lib_ring_buffer *buf = filp->private_data;
1469         struct channel *chan = buf->backend.chan;
1470         const struct lib_ring_buffer_config *config = &chan->backend.config;
1471         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1472         int ret;
1473
1474         if (atomic_read(&chan->record_disabled))
1475                 return -EIO;
1476
1477         switch (cmd) {
1478         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1479         {
1480                 uint64_t ts;
1481
1482                 ret = ops->timestamp_begin(config, buf, &ts);
1483                 if (ret < 0)
1484                         goto error;
1485                 return put_u64(ts, arg);
1486         }
1487         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1488         {
1489                 uint64_t ts;
1490
1491                 ret = ops->timestamp_end(config, buf, &ts);
1492                 if (ret < 0)
1493                         goto error;
1494                 return put_u64(ts, arg);
1495         }
1496         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1497         {
1498                 uint64_t ed;
1499
1500                 ret = ops->events_discarded(config, buf, &ed);
1501                 if (ret < 0)
1502                         goto error;
1503                 return put_u64(ed, arg);
1504         }
1505         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1506         {
1507                 uint64_t cs;
1508
1509                 ret = ops->content_size(config, buf, &cs);
1510                 if (ret < 0)
1511                         goto error;
1512                 return put_u64(cs, arg);
1513         }
1514         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1515         {
1516                 uint64_t ps;
1517
1518                 ret = ops->packet_size(config, buf, &ps);
1519                 if (ret < 0)
1520                         goto error;
1521                 return put_u64(ps, arg);
1522         }
1523         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1524         {
1525                 uint64_t si;
1526
1527                 ret = ops->stream_id(config, buf, &si);
1528                 if (ret < 0)
1529                         goto error;
1530                 return put_u64(si, arg);
1531         }
1532         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1533         {
1534                 uint64_t ts;
1535
1536                 ret = ops->current_timestamp(config, buf, &ts);
1537                 if (ret < 0)
1538                         goto error;
1539                 return put_u64(ts, arg);
1540         }
1541         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1542         {
1543                 uint64_t seq;
1544
1545                 ret = ops->sequence_number(config, buf, &seq);
1546                 if (ret < 0)
1547                         goto error;
1548                 return put_u64(seq, arg);
1549         }
1550         case LTTNG_RING_BUFFER_INSTANCE_ID:
1551         {
1552                 uint64_t id;
1553
1554                 ret = ops->instance_id(config, buf, &id);
1555                 if (ret < 0)
1556                         goto error;
1557                 return put_u64(id, arg);
1558         }
1559         default:
1560                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1561                                 cmd, arg);
1562         }
1563
1564 error:
1565         return -ENOSYS;
1566 }
1567
1568 #ifdef CONFIG_COMPAT
1569 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1570                 unsigned int cmd, unsigned long arg)
1571 {
1572         struct lib_ring_buffer *buf = filp->private_data;
1573         struct channel *chan = buf->backend.chan;
1574         const struct lib_ring_buffer_config *config = &chan->backend.config;
1575         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1576         int ret;
1577
1578         if (atomic_read(&chan->record_disabled))
1579                 return -EIO;
1580
1581         switch (cmd) {
1582         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1583         {
1584                 uint64_t ts;
1585
1586                 ret = ops->timestamp_begin(config, buf, &ts);
1587                 if (ret < 0)
1588                         goto error;
1589                 return put_u64(ts, arg);
1590         }
1591         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1592         {
1593                 uint64_t ts;
1594
1595                 ret = ops->timestamp_end(config, buf, &ts);
1596                 if (ret < 0)
1597                         goto error;
1598                 return put_u64(ts, arg);
1599         }
1600         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1601         {
1602                 uint64_t ed;
1603
1604                 ret = ops->events_discarded(config, buf, &ed);
1605                 if (ret < 0)
1606                         goto error;
1607                 return put_u64(ed, arg);
1608         }
1609         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1610         {
1611                 uint64_t cs;
1612
1613                 ret = ops->content_size(config, buf, &cs);
1614                 if (ret < 0)
1615                         goto error;
1616                 return put_u64(cs, arg);
1617         }
1618         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1619         {
1620                 uint64_t ps;
1621
1622                 ret = ops->packet_size(config, buf, &ps);
1623                 if (ret < 0)
1624                         goto error;
1625                 return put_u64(ps, arg);
1626         }
1627         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1628         {
1629                 uint64_t si;
1630
1631                 ret = ops->stream_id(config, buf, &si);
1632                 if (ret < 0)
1633                         goto error;
1634                 return put_u64(si, arg);
1635         }
1636         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1637         {
1638                 uint64_t ts;
1639
1640                 ret = ops->current_timestamp(config, buf, &ts);
1641                 if (ret < 0)
1642                         goto error;
1643                 return put_u64(ts, arg);
1644         }
1645         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1646         {
1647                 uint64_t seq;
1648
1649                 ret = ops->sequence_number(config, buf, &seq);
1650                 if (ret < 0)
1651                         goto error;
1652                 return put_u64(seq, arg);
1653         }
1654         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1655         {
1656                 uint64_t id;
1657
1658                 ret = ops->instance_id(config, buf, &id);
1659                 if (ret < 0)
1660                         goto error;
1661                 return put_u64(id, arg);
1662         }
1663         default:
1664                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1665                                 cmd, arg);
1666         }
1667
1668 error:
1669         return -ENOSYS;
1670 }
1671 #endif /* CONFIG_COMPAT */
1672
1673 static void lttng_stream_override_ring_buffer_fops(void)
1674 {
1675         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1676         lttng_stream_ring_buffer_file_operations.open =
1677                 lib_ring_buffer_file_operations.open;
1678         lttng_stream_ring_buffer_file_operations.release =
1679                 lib_ring_buffer_file_operations.release;
1680         lttng_stream_ring_buffer_file_operations.poll =
1681                 lib_ring_buffer_file_operations.poll;
1682         lttng_stream_ring_buffer_file_operations.splice_read =
1683                 lib_ring_buffer_file_operations.splice_read;
1684         lttng_stream_ring_buffer_file_operations.mmap =
1685                 lib_ring_buffer_file_operations.mmap;
1686         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1687                 lttng_stream_ring_buffer_ioctl;
1688         lttng_stream_ring_buffer_file_operations.llseek =
1689                 lib_ring_buffer_file_operations.llseek;
1690 #ifdef CONFIG_COMPAT
1691         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1692                 lttng_stream_ring_buffer_compat_ioctl;
1693 #endif
1694 }
1695
1696 int __init lttng_abi_init(void)
1697 {
1698         int ret = 0;
1699
1700         wrapper_vmalloc_sync_all();
1701         lttng_clock_ref();
1702         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1703                                         &lttng_fops, NULL);
1704
1705         if (!lttng_proc_dentry) {
1706                 printk(KERN_ERR "Error creating LTTng control file\n");
1707                 ret = -ENOMEM;
1708                 goto error;
1709         }
1710         lttng_stream_override_ring_buffer_fops();
1711         return 0;
1712
1713 error:
1714         lttng_clock_unref();
1715         return ret;
1716 }
1717
1718 /* No __exit annotation because used by init error path too. */
1719 void lttng_abi_exit(void)
1720 {
1721         lttng_clock_unref();
1722         if (lttng_proc_dentry)
1723                 remove_proc_entry("lttng", NULL);
1724 }