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-string-utils.h>
  55 #include <lttng-abi.h>
  56 #include <lttng-abi-old.h>
  57 #include <lttng-events.h>
  58 #include <lttng-tracer.h>
  59 #include <lttng-tp-mempool.h>
  60 #include <lib/ringbuffer/frontend_types.h>
  61
  62 /*
  63  * This is LTTng's own personal way to create a system call as an external
  64  * module. We use ioctl() on /proc/lttng.
  65  */
  66
  67 static struct proc_dir_entry *lttng_proc_dentry;
  68
  69 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0))
  70 static const struct proc_ops lttng_proc_ops;
  71 #else
  72 static const struct file_operations lttng_proc_ops;
  73 #endif
  74
  75 static const struct file_operations lttng_session_fops;
  76 static const struct file_operations lttng_channel_fops;
  77 static const struct file_operations lttng_metadata_fops;
  78 static const struct file_operations lttng_event_fops;
  79 static struct file_operations lttng_stream_ring_buffer_file_operations;
  80
  81 static int put_u64(uint64_t val, unsigned long arg);
  82
  83 /*
  84  * Teardown management: opened file descriptors keep a refcount on the module,
  85  * so it can only exit when all file descriptors are closed.
  86  */
  87
  88 static
  89 int lttng_abi_create_session(void)
  90 {
  91         struct lttng_session *session;
  92         struct file *session_file;
  93         int session_fd, ret;
  94
  95         session = lttng_session_create();
  96         if (!session)
  97                 return -ENOMEM;
  98         session_fd = lttng_get_unused_fd();
  99         if (session_fd < 0) {
 100                 ret = session_fd;
 101                 goto fd_error;
 102         }
 103         session_file = anon_inode_getfile("[lttng_session]",
 104                                           &lttng_session_fops,
 105                                           session, O_RDWR);
 106         if (IS_ERR(session_file)) {
 107                 ret = PTR_ERR(session_file);
 108                 goto file_error;
 109         }
 110         session->file = session_file;
 111         fd_install(session_fd, session_file);
 112         return session_fd;
 113
 114 file_error:
 115         put_unused_fd(session_fd);
 116 fd_error:
 117         lttng_session_destroy(session);
 118         return ret;
 119 }
 120
 121 static
 122 int lttng_abi_tracepoint_list(void)
 123 {
 124         struct file *tracepoint_list_file;
 125         int file_fd, ret;
 126
 127         file_fd = lttng_get_unused_fd();
 128         if (file_fd < 0) {
 129                 ret = file_fd;
 130                 goto fd_error;
 131         }
 132
 133         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 134                                           &lttng_tracepoint_list_fops,
 135                                           NULL, O_RDWR);
 136         if (IS_ERR(tracepoint_list_file)) {
 137                 ret = PTR_ERR(tracepoint_list_file);
 138                 goto file_error;
 139         }
 140         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 141         if (ret < 0)
 142                 goto open_error;
 143         fd_install(file_fd, tracepoint_list_file);
 144         return file_fd;
 145
 146 open_error:
 147         fput(tracepoint_list_file);
 148 file_error:
 149         put_unused_fd(file_fd);
 150 fd_error:
 151         return ret;
 152 }
 153
 154 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 155 static inline
 156 int lttng_abi_syscall_list(void)
 157 {
 158         return -ENOSYS;
 159 }
 160 #else
 161 static
 162 int lttng_abi_syscall_list(void)
 163 {
 164         struct file *syscall_list_file;
 165         int file_fd, ret;
 166
 167         file_fd = lttng_get_unused_fd();
 168         if (file_fd < 0) {
 169                 ret = file_fd;
 170                 goto fd_error;
 171         }
 172
 173         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 174                                           &lttng_syscall_list_fops,
 175                                           NULL, O_RDWR);
 176         if (IS_ERR(syscall_list_file)) {
 177                 ret = PTR_ERR(syscall_list_file);
 178                 goto file_error;
 179         }
 180         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 181         if (ret < 0)
 182                 goto open_error;
 183         fd_install(file_fd, syscall_list_file);
 184         return file_fd;
 185
 186 open_error:
 187         fput(syscall_list_file);
 188 file_error:
 189         put_unused_fd(file_fd);
 190 fd_error:
 191         return ret;
 192 }
 193 #endif
 194
 195 static
 196 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 197 {
 198         v->major = LTTNG_MODULES_MAJOR_VERSION;
 199         v->minor = LTTNG_MODULES_MINOR_VERSION;
 200         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 201 }
 202
 203 static
 204 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 205 {
 206         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 207         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 208 }
 209
 210 static
 211 long lttng_abi_add_context(struct file *file,
 212         struct lttng_kernel_context *context_param,
 213         struct lttng_ctx **ctx, struct lttng_session *session)
 214 {
 215
 216         if (session->been_active)
 217                 return -EPERM;
 218
 219         switch (context_param->ctx) {
 220         case LTTNG_KERNEL_CONTEXT_PID:
 221                 return lttng_add_pid_to_ctx(ctx);
 222         case LTTNG_KERNEL_CONTEXT_PRIO:
 223                 return lttng_add_prio_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_NICE:
 225                 return lttng_add_nice_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_VPID:
 227                 return lttng_add_vpid_to_ctx(ctx);
 228         case LTTNG_KERNEL_CONTEXT_TID:
 229                 return lttng_add_tid_to_ctx(ctx);
 230         case LTTNG_KERNEL_CONTEXT_VTID:
 231                 return lttng_add_vtid_to_ctx(ctx);
 232         case LTTNG_KERNEL_CONTEXT_PPID:
 233                 return lttng_add_ppid_to_ctx(ctx);
 234         case LTTNG_KERNEL_CONTEXT_VPPID:
 235                 return lttng_add_vppid_to_ctx(ctx);
 236         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 237                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 238                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 239                                 context_param->u.perf_counter.config,
 240                                 context_param->u.perf_counter.name,
 241                                 ctx);
 242         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 243                 return lttng_add_procname_to_ctx(ctx);
 244         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 245                 return lttng_add_hostname_to_ctx(ctx);
 246         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 247                 return lttng_add_cpu_id_to_ctx(ctx);
 248         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 249                 return lttng_add_interruptible_to_ctx(ctx);
 250         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 251                 return lttng_add_need_reschedule_to_ctx(ctx);
 252         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 253                 return lttng_add_preemptible_to_ctx(ctx);
 254         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 255                 return lttng_add_migratable_to_ctx(ctx);
 256         default:
 257                 return -EINVAL;
 258         }
 259 }
 260
 261 /**
 262  *      lttng_ioctl - lttng syscall through ioctl
 263  *
 264  *      @file: the file
 265  *      @cmd: the command
 266  *      @arg: command arg
 267  *
 268  *      This ioctl implements lttng commands:
 269  *      LTTNG_KERNEL_SESSION
 270  *              Returns a LTTng trace session file descriptor
 271  *      LTTNG_KERNEL_TRACER_VERSION
 272  *              Returns the LTTng kernel tracer version
 273  *      LTTNG_KERNEL_TRACEPOINT_LIST
 274  *              Returns a file descriptor listing available tracepoints
 275  *      LTTNG_KERNEL_WAIT_QUIESCENT
 276  *              Returns after all previously running probes have completed
 277  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 278  *              Returns the LTTng kernel tracer ABI version
 279  *
 280  * The returned session will be deleted when its file descriptor is closed.
 281  */
 282 static
 283 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 284 {
 285         switch (cmd) {
 286         case LTTNG_KERNEL_OLD_SESSION:
 287         case LTTNG_KERNEL_SESSION:
 288                 return lttng_abi_create_session();
 289         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 290         {
 291                 struct lttng_kernel_tracer_version v;
 292                 struct lttng_kernel_old_tracer_version oldv;
 293                 struct lttng_kernel_old_tracer_version *uversion =
 294                         (struct lttng_kernel_old_tracer_version __user *) arg;
 295
 296                 lttng_abi_tracer_version(&v);
 297                 oldv.major = v.major;
 298                 oldv.minor = v.minor;
 299                 oldv.patchlevel = v.patchlevel;
 300
 301                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 302                         return -EFAULT;
 303                 return 0;
 304         }
 305         case LTTNG_KERNEL_TRACER_VERSION:
 306         {
 307                 struct lttng_kernel_tracer_version version;
 308                 struct lttng_kernel_tracer_version *uversion =
 309                         (struct lttng_kernel_tracer_version __user *) arg;
 310
 311                 lttng_abi_tracer_version(&version);
 312
 313                 if (copy_to_user(uversion, &version, sizeof(version)))
 314                         return -EFAULT;
 315                 return 0;
 316         }
 317         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 318         {
 319                 struct lttng_kernel_tracer_abi_version version;
 320                 struct lttng_kernel_tracer_abi_version *uversion =
 321                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 322
 323                 lttng_abi_tracer_abi_version(&version);
 324
 325                 if (copy_to_user(uversion, &version, sizeof(version)))
 326                         return -EFAULT;
 327                 return 0;
 328         }
 329         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 330         case LTTNG_KERNEL_TRACEPOINT_LIST:
 331                 return lttng_abi_tracepoint_list();
 332         case LTTNG_KERNEL_SYSCALL_LIST:
 333                 return lttng_abi_syscall_list();
 334         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 335         case LTTNG_KERNEL_WAIT_QUIESCENT:
 336                 synchronize_trace();
 337                 return 0;
 338         case LTTNG_KERNEL_OLD_CALIBRATE:
 339         {
 340                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 341                         (struct lttng_kernel_old_calibrate __user *) arg;
 342                 struct lttng_kernel_old_calibrate old_calibrate;
 343                 struct lttng_kernel_calibrate calibrate;
 344                 int ret;
 345
 346                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 347                         return -EFAULT;
 348                 calibrate.type = old_calibrate.type;
 349                 ret = lttng_calibrate(&calibrate);
 350                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 351                         return -EFAULT;
 352                 return ret;
 353         }
 354         case LTTNG_KERNEL_CALIBRATE:
 355         {
 356                 struct lttng_kernel_calibrate __user *ucalibrate =
 357                         (struct lttng_kernel_calibrate __user *) arg;
 358                 struct lttng_kernel_calibrate calibrate;
 359                 int ret;
 360
 361                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 362                         return -EFAULT;
 363                 ret = lttng_calibrate(&calibrate);
 364                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 365                         return -EFAULT;
 366                 return ret;
 367         }
 368         default:
 369                 return -ENOIOCTLCMD;
 370         }
 371 }
 372
 373 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0))
 374 static const struct proc_ops lttng_proc_ops = {
 375         .proc_ioctl = lttng_ioctl,
 376 #ifdef CONFIG_COMPAT
 377         .proc_compat_ioctl = lttng_ioctl,
 378 #endif /* CONFIG_COMPAT */
 379 };
 380 #else
 381 static const struct file_operations lttng_proc_ops = {
 382         .owner = THIS_MODULE,
 383         .unlocked_ioctl = lttng_ioctl,
 384 #ifdef CONFIG_COMPAT
 385         .compat_ioctl = lttng_ioctl,
 386 #endif /* CONFIG_COMPAT */
 387 };
 388 #endif
 389
 390 static
 391 int lttng_abi_create_channel(struct file *session_file,
 392                              struct lttng_kernel_channel *chan_param,
 393                              enum channel_type channel_type)
 394 {
 395         struct lttng_session *session = session_file->private_data;
 396         const struct file_operations *fops = NULL;
 397         const char *transport_name;
 398         struct lttng_channel *chan;
 399         struct file *chan_file;
 400         int chan_fd;
 401         int ret = 0;
 402
 403         chan_fd = lttng_get_unused_fd();
 404         if (chan_fd < 0) {
 405                 ret = chan_fd;
 406                 goto fd_error;
 407         }
 408         switch (channel_type) {
 409         case PER_CPU_CHANNEL:
 410                 fops = &lttng_channel_fops;
 411                 break;
 412         case METADATA_CHANNEL:
 413                 fops = &lttng_metadata_fops;
 414                 break;
 415         }
 416
 417         chan_file = anon_inode_getfile("[lttng_channel]",
 418                                        fops,
 419                                        NULL, O_RDWR);
 420         if (IS_ERR(chan_file)) {
 421                 ret = PTR_ERR(chan_file);
 422                 goto file_error;
 423         }
 424         switch (channel_type) {
 425         case PER_CPU_CHANNEL:
 426                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 427                         transport_name = chan_param->overwrite ?
 428                                 "relay-overwrite" : "relay-discard";
 429                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 430                         transport_name = chan_param->overwrite ?
 431                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 432                 } else {
 433                         return -EINVAL;
 434                 }
 435                 break;
 436         case METADATA_CHANNEL:
 437                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 438                         transport_name = "relay-metadata";
 439                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 440                         transport_name = "relay-metadata-mmap";
 441                 else
 442                         return -EINVAL;
 443                 break;
 444         default:
 445                 transport_name = "<unknown>";
 446                 break;
 447         }
 448         if (!atomic_long_add_unless(&session_file->f_count, 1, LONG_MAX)) {
 449                 ret = -EOVERFLOW;
 450                 goto refcount_error;
 451         }
 452         /*
 453          * We tolerate no failure path after channel creation. It will stay
 454          * invariant for the rest of the session.
 455          */
 456         chan = lttng_channel_create(session, transport_name, NULL,
 457                                   chan_param->subbuf_size,
 458                                   chan_param->num_subbuf,
 459                                   chan_param->switch_timer_interval,
 460                                   chan_param->read_timer_interval,
 461                                   channel_type);
 462         if (!chan) {
 463                 ret = -EINVAL;
 464                 goto chan_error;
 465         }
 466         chan->file = chan_file;
 467         chan_file->private_data = chan;
 468         fd_install(chan_fd, chan_file);
 469
 470         return chan_fd;
 471
 472 chan_error:
 473         atomic_long_dec(&session_file->f_count);
 474 refcount_error:
 475         fput(chan_file);
 476 file_error:
 477         put_unused_fd(chan_fd);
 478 fd_error:
 479         return ret;
 480 }
 481
 482 /**
 483  *      lttng_session_ioctl - lttng session fd ioctl
 484  *
 485  *      @file: the file
 486  *      @cmd: the command
 487  *      @arg: command arg
 488  *
 489  *      This ioctl implements lttng commands:
 490  *      LTTNG_KERNEL_CHANNEL
 491  *              Returns a LTTng channel file descriptor
 492  *      LTTNG_KERNEL_ENABLE
 493  *              Enables tracing for a session (weak enable)
 494  *      LTTNG_KERNEL_DISABLE
 495  *              Disables tracing for a session (strong disable)
 496  *      LTTNG_KERNEL_METADATA
 497  *              Returns a LTTng metadata file descriptor
 498  *      LTTNG_KERNEL_SESSION_TRACK_PID
 499  *              Add PID to session tracker
 500  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 501  *              Remove PID from session tracker
 502  *
 503  * The returned channel will be deleted when its file descriptor is closed.
 504  */
 505 static
 506 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 507 {
 508         struct lttng_session *session = file->private_data;
 509         struct lttng_kernel_channel chan_param;
 510         struct lttng_kernel_old_channel old_chan_param;
 511
 512         switch (cmd) {
 513         case LTTNG_KERNEL_OLD_CHANNEL:
 514         {
 515                 if (copy_from_user(&old_chan_param,
 516                                 (struct lttng_kernel_old_channel __user *) arg,
 517                                 sizeof(struct lttng_kernel_old_channel)))
 518                         return -EFAULT;
 519                 chan_param.overwrite = old_chan_param.overwrite;
 520                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 521                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 522                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 523                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 524                 chan_param.output = old_chan_param.output;
 525
 526                 return lttng_abi_create_channel(file, &chan_param,
 527                                 PER_CPU_CHANNEL);
 528         }
 529         case LTTNG_KERNEL_CHANNEL:
 530         {
 531                 if (copy_from_user(&chan_param,
 532                                 (struct lttng_kernel_channel __user *) arg,
 533                                 sizeof(struct lttng_kernel_channel)))
 534                         return -EFAULT;
 535                 return lttng_abi_create_channel(file, &chan_param,
 536                                 PER_CPU_CHANNEL);
 537         }
 538         case LTTNG_KERNEL_OLD_SESSION_START:
 539         case LTTNG_KERNEL_OLD_ENABLE:
 540         case LTTNG_KERNEL_SESSION_START:
 541         case LTTNG_KERNEL_ENABLE:
 542                 return lttng_session_enable(session);
 543         case LTTNG_KERNEL_OLD_SESSION_STOP:
 544         case LTTNG_KERNEL_OLD_DISABLE:
 545         case LTTNG_KERNEL_SESSION_STOP:
 546         case LTTNG_KERNEL_DISABLE:
 547                 return lttng_session_disable(session);
 548         case LTTNG_KERNEL_OLD_METADATA:
 549         {
 550                 if (copy_from_user(&old_chan_param,
 551                                 (struct lttng_kernel_old_channel __user *) arg,
 552                                 sizeof(struct lttng_kernel_old_channel)))
 553                         return -EFAULT;
 554                 chan_param.overwrite = old_chan_param.overwrite;
 555                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 556                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 557                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 558                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 559                 chan_param.output = old_chan_param.output;
 560
 561                 return lttng_abi_create_channel(file, &chan_param,
 562                                 METADATA_CHANNEL);
 563         }
 564         case LTTNG_KERNEL_METADATA:
 565         {
 566                 if (copy_from_user(&chan_param,
 567                                         (struct lttng_kernel_channel __user *) arg,
 568                                         sizeof(struct lttng_kernel_channel)))
 569                         return -EFAULT;
 570                 return lttng_abi_create_channel(file, &chan_param,
 571                                 METADATA_CHANNEL);
 572         }
 573         case LTTNG_KERNEL_SESSION_TRACK_PID:
 574                 return lttng_session_track_pid(session, (int) arg);
 575         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 576                 return lttng_session_untrack_pid(session, (int) arg);
 577         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 578                 return lttng_session_list_tracker_pids(session);
 579         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 580                 return lttng_session_metadata_regenerate(session);
 581         case LTTNG_KERNEL_SESSION_STATEDUMP:
 582                 return lttng_session_statedump(session);
 583         default:
 584                 return -ENOIOCTLCMD;
 585         }
 586 }
 587
 588 /*
 589  * Called when the last file reference is dropped.
 590  *
 591  * Big fat note: channels and events are invariant for the whole session after
 592  * their creation. So this session destruction also destroys all channel and
 593  * event structures specific to this session (they are not destroyed when their
 594  * individual file is released).
 595  */
 596 static
 597 int lttng_session_release(struct inode *inode, struct file *file)
 598 {
 599         struct lttng_session *session = file->private_data;
 600
 601         if (session)
 602                 lttng_session_destroy(session);
 603         return 0;
 604 }
 605
 606 static const struct file_operations lttng_session_fops = {
 607         .owner = THIS_MODULE,
 608         .release = lttng_session_release,
 609         .unlocked_ioctl = lttng_session_ioctl,
 610 #ifdef CONFIG_COMPAT
 611         .compat_ioctl = lttng_session_ioctl,
 612 #endif
 613 };
 614
 615 /**
 616  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 617  *      @filp: the file
 618  *      @wait: poll table
 619  *
 620  *      Handles the poll operations for the metadata channels.
 621  */
 622 static
 623 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 624                 poll_table *wait)
 625 {
 626         struct lttng_metadata_stream *stream = filp->private_data;
 627         struct lib_ring_buffer *buf = stream->priv;
 628         int finalized;
 629         unsigned int mask = 0;
 630
 631         if (filp->f_mode & FMODE_READ) {
 632                 poll_wait_set_exclusive(wait);
 633                 poll_wait(filp, &stream->read_wait, wait);
 634
 635                 finalized = stream->finalized;
 636
 637                 /*
 638                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 639                  * ordering finalized load before offsets loads.
 640                  */
 641                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 642
 643                 if (finalized)
 644                         mask |= POLLHUP;
 645
 646                 mutex_lock(&stream->metadata_cache->lock);
 647                 if (stream->metadata_cache->metadata_written >
 648                                 stream->metadata_out)
 649                         mask |= POLLIN;
 650                 mutex_unlock(&stream->metadata_cache->lock);
 651         }
 652
 653         return mask;
 654 }
 655
 656 static
 657 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 658                 unsigned int cmd, unsigned long arg)
 659 {
 660         struct lttng_metadata_stream *stream = filp->private_data;
 661
 662         stream->metadata_out = stream->metadata_in;
 663 }
 664
 665 static
 666 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 667                 unsigned int cmd, unsigned long arg)
 668 {
 669         int ret;
 670         struct lttng_metadata_stream *stream = filp->private_data;
 671         struct lib_ring_buffer *buf = stream->priv;
 672
 673         switch (cmd) {
 674         case RING_BUFFER_GET_NEXT_SUBBUF:
 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                 ret = lttng_metadata_output_channel(stream, chan);
 681                 if (ret > 0) {
 682                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 683                         ret = 0;
 684                 } else if (ret < 0)
 685                         goto err;
 686                 break;
 687         }
 688         case RING_BUFFER_GET_SUBBUF:
 689         {
 690                 /*
 691                  * Random access is not allowed for metadata channel.
 692                  */
 693                 return -ENOSYS;
 694         }
 695         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 696         case RING_BUFFER_FLUSH:
 697         {
 698                 struct lttng_metadata_stream *stream = filp->private_data;
 699                 struct lib_ring_buffer *buf = stream->priv;
 700                 struct channel *chan = buf->backend.chan;
 701
 702                 /*
 703                  * Before doing the actual ring buffer flush, write up to one
 704                  * packet of metadata in the ring buffer.
 705                  */
 706                 ret = lttng_metadata_output_channel(stream, chan);
 707                 if (ret < 0)
 708                         goto err;
 709                 break;
 710         }
 711         case RING_BUFFER_GET_METADATA_VERSION:
 712         {
 713                 struct lttng_metadata_stream *stream = filp->private_data;
 714
 715                 return put_u64(stream->version, arg);
 716         }
 717         default:
 718                 break;
 719         }
 720         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 721
 722         /* Performing lib ring buffer ioctl after our own. */
 723         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 724         if (ret < 0)
 725                 goto err;
 726
 727         switch (cmd) {
 728         case RING_BUFFER_PUT_NEXT_SUBBUF:
 729         {
 730                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 731                                 cmd, arg);
 732                 break;
 733         }
 734         default:
 735                 break;
 736         }
 737 err:
 738         return ret;
 739 }
 740
 741 #ifdef CONFIG_COMPAT
 742 static
 743 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 744                 unsigned int cmd, unsigned long arg)
 745 {
 746         int ret;
 747         struct lttng_metadata_stream *stream = filp->private_data;
 748         struct lib_ring_buffer *buf = stream->priv;
 749
 750         switch (cmd) {
 751         case RING_BUFFER_GET_NEXT_SUBBUF:
 752         {
 753                 struct lttng_metadata_stream *stream = filp->private_data;
 754                 struct lib_ring_buffer *buf = stream->priv;
 755                 struct channel *chan = buf->backend.chan;
 756
 757                 ret = lttng_metadata_output_channel(stream, chan);
 758                 if (ret > 0) {
 759                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 760                         ret = 0;
 761                 } else if (ret < 0)
 762                         goto err;
 763                 break;
 764         }
 765         case RING_BUFFER_GET_SUBBUF:
 766         {
 767                 /*
 768                  * Random access is not allowed for metadata channel.
 769                  */
 770                 return -ENOSYS;
 771         }
 772         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 773         case RING_BUFFER_FLUSH:
 774         {
 775                 struct lttng_metadata_stream *stream = filp->private_data;
 776                 struct lib_ring_buffer *buf = stream->priv;
 777                 struct channel *chan = buf->backend.chan;
 778
 779                 /*
 780                  * Before doing the actual ring buffer flush, write up to one
 781                  * packet of metadata in the ring buffer.
 782                  */
 783                 ret = lttng_metadata_output_channel(stream, chan);
 784                 if (ret < 0)
 785                         goto err;
 786                 break;
 787         }
 788         case RING_BUFFER_GET_METADATA_VERSION:
 789         {
 790                 struct lttng_metadata_stream *stream = filp->private_data;
 791
 792                 return put_u64(stream->version, arg);
 793         }
 794         default:
 795                 break;
 796         }
 797         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 798
 799         /* Performing lib ring buffer ioctl after our own. */
 800         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 801         if (ret < 0)
 802                 goto err;
 803
 804         switch (cmd) {
 805         case RING_BUFFER_PUT_NEXT_SUBBUF:
 806         {
 807                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 808                                 cmd, arg);
 809                 break;
 810         }
 811         default:
 812                 break;
 813         }
 814 err:
 815         return ret;
 816 }
 817 #endif
 818
 819 /*
 820  * This is not used by anonymous file descriptors. This code is left
 821  * there if we ever want to implement an inode with open() operation.
 822  */
 823 static
 824 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 825 {
 826         struct lttng_metadata_stream *stream = inode->i_private;
 827         struct lib_ring_buffer *buf = stream->priv;
 828
 829         file->private_data = buf;
 830         /*
 831          * Since life-time of metadata cache differs from that of
 832          * session, we need to keep our own reference on the transport.
 833          */
 834         if (!try_module_get(stream->transport->owner)) {
 835                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 836                 return -EBUSY;
 837         }
 838         return lib_ring_buffer_open(inode, file, buf);
 839 }
 840
 841 static
 842 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 843 {
 844         struct lttng_metadata_stream *stream = file->private_data;
 845         struct lib_ring_buffer *buf = stream->priv;
 846
 847         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 848         module_put(stream->transport->owner);
 849         return lib_ring_buffer_release(inode, file, buf);
 850 }
 851
 852 static
 853 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 854                 struct pipe_inode_info *pipe, size_t len,
 855                 unsigned int flags)
 856 {
 857         struct lttng_metadata_stream *stream = in->private_data;
 858         struct lib_ring_buffer *buf = stream->priv;
 859
 860         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 861                         flags, buf);
 862 }
 863
 864 static
 865 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 866                 struct vm_area_struct *vma)
 867 {
 868         struct lttng_metadata_stream *stream = filp->private_data;
 869         struct lib_ring_buffer *buf = stream->priv;
 870
 871         return lib_ring_buffer_mmap(filp, vma, buf);
 872 }
 873
 874 static
 875 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 876         .owner = THIS_MODULE,
 877         .open = lttng_metadata_ring_buffer_open,
 878         .release = lttng_metadata_ring_buffer_release,
 879         .poll = lttng_metadata_ring_buffer_poll,
 880         .splice_read = lttng_metadata_ring_buffer_splice_read,
 881         .mmap = lttng_metadata_ring_buffer_mmap,
 882         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 883         .llseek = vfs_lib_ring_buffer_no_llseek,
 884 #ifdef CONFIG_COMPAT
 885         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 886 #endif
 887 };
 888
 889 static
 890 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 891                 const struct file_operations *fops)
 892 {
 893         int stream_fd, ret;
 894         struct file *stream_file;
 895
 896         stream_fd = lttng_get_unused_fd();
 897         if (stream_fd < 0) {
 898                 ret = stream_fd;
 899                 goto fd_error;
 900         }
 901         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 902                         stream_priv, O_RDWR);
 903         if (IS_ERR(stream_file)) {
 904                 ret = PTR_ERR(stream_file);
 905                 goto file_error;
 906         }
 907         /*
 908          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 909          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 910          * file descriptor, so we set FMODE_PREAD here.
 911          */
 912         stream_file->f_mode |= FMODE_PREAD;
 913         fd_install(stream_fd, stream_file);
 914         /*
 915          * The stream holds a reference to the channel within the generic ring
 916          * buffer library, so no need to hold a refcount on the channel and
 917          * session files here.
 918          */
 919         return stream_fd;
 920
 921 file_error:
 922         put_unused_fd(stream_fd);
 923 fd_error:
 924         return ret;
 925 }
 926
 927 static
 928 int lttng_abi_open_stream(struct file *channel_file)
 929 {
 930         struct lttng_channel *channel = channel_file->private_data;
 931         struct lib_ring_buffer *buf;
 932         int ret;
 933         void *stream_priv;
 934
 935         buf = channel->ops->buffer_read_open(channel->chan);
 936         if (!buf)
 937                 return -ENOENT;
 938
 939         stream_priv = buf;
 940         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 941                         &lttng_stream_ring_buffer_file_operations);
 942         if (ret < 0)
 943                 goto fd_error;
 944
 945         return ret;
 946
 947 fd_error:
 948         channel->ops->buffer_read_close(buf);
 949         return ret;
 950 }
 951
 952 static
 953 int lttng_abi_open_metadata_stream(struct file *channel_file)
 954 {
 955         struct lttng_channel *channel = channel_file->private_data;
 956         struct lttng_session *session = channel->session;
 957         struct lib_ring_buffer *buf;
 958         int ret;
 959         struct lttng_metadata_stream *metadata_stream;
 960         void *stream_priv;
 961
 962         buf = channel->ops->buffer_read_open(channel->chan);
 963         if (!buf)
 964                 return -ENOENT;
 965
 966         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 967                         GFP_KERNEL);
 968         if (!metadata_stream) {
 969                 ret = -ENOMEM;
 970                 goto nomem;
 971         }
 972         metadata_stream->metadata_cache = session->metadata_cache;
 973         init_waitqueue_head(&metadata_stream->read_wait);
 974         metadata_stream->priv = buf;
 975         stream_priv = metadata_stream;
 976         metadata_stream->transport = channel->transport;
 977
 978         /*
 979          * Since life-time of metadata cache differs from that of
 980          * session, we need to keep our own reference on the transport.
 981          */
 982         if (!try_module_get(metadata_stream->transport->owner)) {
 983                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 984                 ret = -EINVAL;
 985                 goto notransport;
 986         }
 987
 988         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
 989                 ret = -EOVERFLOW;
 990                 goto kref_error;
 991         }
 992
 993         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 994                         &lttng_metadata_ring_buffer_file_operations);
 995         if (ret < 0)
 996                 goto fd_error;
 997
 998         list_add(&metadata_stream->list,
 999                 &session->metadata_cache->metadata_stream);
1000         return ret;
1001
1002 fd_error:
1003         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1004 kref_error:
1005         module_put(metadata_stream->transport->owner);
1006 notransport:
1007         kfree(metadata_stream);
1008 nomem:
1009         channel->ops->buffer_read_close(buf);
1010         return ret;
1011 }
1012
1013 static
1014 int lttng_abi_create_event(struct file *channel_file,
1015                            struct lttng_kernel_event *event_param)
1016 {
1017         struct lttng_channel *channel = channel_file->private_data;
1018         int event_fd, ret;
1019         struct file *event_file;
1020         void *priv;
1021
1022         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1023         switch (event_param->instrumentation) {
1024         case LTTNG_KERNEL_KRETPROBE:
1025                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1026                 break;
1027         case LTTNG_KERNEL_KPROBE:
1028                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1029                 break;
1030         case LTTNG_KERNEL_FUNCTION:
1031                 WARN_ON_ONCE(1);
1032                 /* Not implemented. */
1033                 break;
1034         default:
1035                 break;
1036         }
1037         event_fd = lttng_get_unused_fd();
1038         if (event_fd < 0) {
1039                 ret = event_fd;
1040                 goto fd_error;
1041         }
1042         event_file = anon_inode_getfile("[lttng_event]",
1043                                         &lttng_event_fops,
1044                                         NULL, O_RDWR);
1045         if (IS_ERR(event_file)) {
1046                 ret = PTR_ERR(event_file);
1047                 goto file_error;
1048         }
1049         /* The event holds a reference on the channel */
1050         if (!atomic_long_add_unless(&channel_file->f_count, 1, LONG_MAX)) {
1051                 ret = -EOVERFLOW;
1052                 goto refcount_error;
1053         }
1054         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1055                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1056                 struct lttng_enabler *enabler;
1057
1058                 if (strutils_is_star_glob_pattern(event_param->name)) {
1059                         /*
1060                          * If the event name is a star globbing pattern,
1061                          * we create the special star globbing enabler.
1062                          */
1063                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1064                                 event_param, channel);
1065                 } else {
1066                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1067                                 event_param, channel);
1068                 }
1069                 priv = enabler;
1070         } else {
1071                 struct lttng_event *event;
1072
1073                 /*
1074                  * We tolerate no failure path after event creation. It
1075                  * will stay invariant for the rest of the session.
1076                  */
1077                 event = lttng_event_create(channel, event_param,
1078                                 NULL, NULL,
1079                                 event_param->instrumentation);
1080                 WARN_ON_ONCE(!event);
1081                 if (IS_ERR(event)) {
1082                         ret = PTR_ERR(event);
1083                         goto event_error;
1084                 }
1085                 priv = event;
1086         }
1087         event_file->private_data = priv;
1088         fd_install(event_fd, event_file);
1089         return event_fd;
1090
1091 event_error:
1092         atomic_long_dec(&channel_file->f_count);
1093 refcount_error:
1094         fput(event_file);
1095 file_error:
1096         put_unused_fd(event_fd);
1097 fd_error:
1098         return ret;
1099 }
1100
1101 /**
1102  *      lttng_channel_ioctl - lttng syscall through ioctl
1103  *
1104  *      @file: the file
1105  *      @cmd: the command
1106  *      @arg: command arg
1107  *
1108  *      This ioctl implements lttng commands:
1109  *      LTTNG_KERNEL_STREAM
1110  *              Returns an event stream file descriptor or failure.
1111  *              (typically, one event stream records events from one CPU)
1112  *      LTTNG_KERNEL_EVENT
1113  *              Returns an event file descriptor or failure.
1114  *      LTTNG_KERNEL_CONTEXT
1115  *              Prepend a context field to each event in the channel
1116  *      LTTNG_KERNEL_ENABLE
1117  *              Enable recording for events in this channel (weak enable)
1118  *      LTTNG_KERNEL_DISABLE
1119  *              Disable recording for events in this channel (strong disable)
1120  *
1121  * Channel and event file descriptors also hold a reference on the session.
1122  */
1123 static
1124 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1125 {
1126         struct lttng_channel *channel = file->private_data;
1127
1128         switch (cmd) {
1129         case LTTNG_KERNEL_OLD_STREAM:
1130         case LTTNG_KERNEL_STREAM:
1131                 return lttng_abi_open_stream(file);
1132         case LTTNG_KERNEL_OLD_EVENT:
1133         {
1134                 struct lttng_kernel_event *uevent_param;
1135                 struct lttng_kernel_old_event *old_uevent_param;
1136                 int ret;
1137
1138                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1139                                 GFP_KERNEL);
1140                 if (!uevent_param) {
1141                         ret = -ENOMEM;
1142                         goto old_event_end;
1143                 }
1144                 old_uevent_param = kmalloc(
1145                                 sizeof(struct lttng_kernel_old_event),
1146                                 GFP_KERNEL);
1147                 if (!old_uevent_param) {
1148                         ret = -ENOMEM;
1149                         goto old_event_error_free_param;
1150                 }
1151                 if (copy_from_user(old_uevent_param,
1152                                 (struct lttng_kernel_old_event __user *) arg,
1153                                 sizeof(struct lttng_kernel_old_event))) {
1154                         ret = -EFAULT;
1155                         goto old_event_error_free_old_param;
1156                 }
1157
1158                 memcpy(uevent_param->name, old_uevent_param->name,
1159                                 sizeof(uevent_param->name));
1160                 uevent_param->instrumentation =
1161                         old_uevent_param->instrumentation;
1162
1163                 switch (old_uevent_param->instrumentation) {
1164                 case LTTNG_KERNEL_KPROBE:
1165                         uevent_param->u.kprobe.addr =
1166                                 old_uevent_param->u.kprobe.addr;
1167                         uevent_param->u.kprobe.offset =
1168                                 old_uevent_param->u.kprobe.offset;
1169                         memcpy(uevent_param->u.kprobe.symbol_name,
1170                                 old_uevent_param->u.kprobe.symbol_name,
1171                                 sizeof(uevent_param->u.kprobe.symbol_name));
1172                         break;
1173                 case LTTNG_KERNEL_KRETPROBE:
1174                         uevent_param->u.kretprobe.addr =
1175                                 old_uevent_param->u.kretprobe.addr;
1176                         uevent_param->u.kretprobe.offset =
1177                                 old_uevent_param->u.kretprobe.offset;
1178                         memcpy(uevent_param->u.kretprobe.symbol_name,
1179                                 old_uevent_param->u.kretprobe.symbol_name,
1180                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1181                         break;
1182                 case LTTNG_KERNEL_FUNCTION:
1183                         WARN_ON_ONCE(1);
1184                         /* Not implemented. */
1185                         break;
1186                 default:
1187                         break;
1188                 }
1189                 ret = lttng_abi_create_event(file, uevent_param);
1190
1191 old_event_error_free_old_param:
1192                 kfree(old_uevent_param);
1193 old_event_error_free_param:
1194                 kfree(uevent_param);
1195 old_event_end:
1196                 return ret;
1197         }
1198         case LTTNG_KERNEL_EVENT:
1199         {
1200                 struct lttng_kernel_event uevent_param;
1201
1202                 if (copy_from_user(&uevent_param,
1203                                 (struct lttng_kernel_event __user *) arg,
1204                                 sizeof(uevent_param)))
1205                         return -EFAULT;
1206                 return lttng_abi_create_event(file, &uevent_param);
1207         }
1208         case LTTNG_KERNEL_OLD_CONTEXT:
1209         {
1210                 struct lttng_kernel_context *ucontext_param;
1211                 struct lttng_kernel_old_context *old_ucontext_param;
1212                 int ret;
1213
1214                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1215                                 GFP_KERNEL);
1216                 if (!ucontext_param) {
1217                         ret = -ENOMEM;
1218                         goto old_ctx_end;
1219                 }
1220                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1221                                 GFP_KERNEL);
1222                 if (!old_ucontext_param) {
1223                         ret = -ENOMEM;
1224                         goto old_ctx_error_free_param;
1225                 }
1226
1227                 if (copy_from_user(old_ucontext_param,
1228                                 (struct lttng_kernel_old_context __user *) arg,
1229                                 sizeof(struct lttng_kernel_old_context))) {
1230                         ret = -EFAULT;
1231                         goto old_ctx_error_free_old_param;
1232                 }
1233                 ucontext_param->ctx = old_ucontext_param->ctx;
1234                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1235                                 sizeof(ucontext_param->padding));
1236                 /* only type that uses the union */
1237                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1238                         ucontext_param->u.perf_counter.type =
1239                                 old_ucontext_param->u.perf_counter.type;
1240                         ucontext_param->u.perf_counter.config =
1241                                 old_ucontext_param->u.perf_counter.config;
1242                         memcpy(ucontext_param->u.perf_counter.name,
1243                                 old_ucontext_param->u.perf_counter.name,
1244                                 sizeof(ucontext_param->u.perf_counter.name));
1245                 }
1246
1247                 ret = lttng_abi_add_context(file,
1248                                 ucontext_param,
1249                                 &channel->ctx, channel->session);
1250
1251 old_ctx_error_free_old_param:
1252                 kfree(old_ucontext_param);
1253 old_ctx_error_free_param:
1254                 kfree(ucontext_param);
1255 old_ctx_end:
1256                 return ret;
1257         }
1258         case LTTNG_KERNEL_CONTEXT:
1259         {
1260                 struct lttng_kernel_context ucontext_param;
1261
1262                 if (copy_from_user(&ucontext_param,
1263                                 (struct lttng_kernel_context __user *) arg,
1264                                 sizeof(ucontext_param)))
1265                         return -EFAULT;
1266                 return lttng_abi_add_context(file,
1267                                 &ucontext_param,
1268                                 &channel->ctx, channel->session);
1269         }
1270         case LTTNG_KERNEL_OLD_ENABLE:
1271         case LTTNG_KERNEL_ENABLE:
1272                 return lttng_channel_enable(channel);
1273         case LTTNG_KERNEL_OLD_DISABLE:
1274         case LTTNG_KERNEL_DISABLE:
1275                 return lttng_channel_disable(channel);
1276         case LTTNG_KERNEL_SYSCALL_MASK:
1277                 return lttng_channel_syscall_mask(channel,
1278                         (struct lttng_kernel_syscall_mask __user *) arg);
1279         default:
1280                 return -ENOIOCTLCMD;
1281         }
1282
1283 }
1284
1285 /**
1286  *      lttng_metadata_ioctl - lttng syscall through ioctl
1287  *
1288  *      @file: the file
1289  *      @cmd: the command
1290  *      @arg: command arg
1291  *
1292  *      This ioctl implements lttng commands:
1293  *      LTTNG_KERNEL_STREAM
1294  *              Returns an event stream file descriptor or failure.
1295  *
1296  * Channel and event file descriptors also hold a reference on the session.
1297  */
1298 static
1299 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1300 {
1301         switch (cmd) {
1302         case LTTNG_KERNEL_OLD_STREAM:
1303         case LTTNG_KERNEL_STREAM:
1304                 return lttng_abi_open_metadata_stream(file);
1305         default:
1306                 return -ENOIOCTLCMD;
1307         }
1308 }
1309
1310 /**
1311  *      lttng_channel_poll - lttng stream addition/removal monitoring
1312  *
1313  *      @file: the file
1314  *      @wait: poll table
1315  */
1316 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1317 {
1318         struct lttng_channel *channel = file->private_data;
1319         unsigned int mask = 0;
1320
1321         if (file->f_mode & FMODE_READ) {
1322                 poll_wait_set_exclusive(wait);
1323                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1324                           wait);
1325
1326                 if (channel->ops->is_disabled(channel->chan))
1327                         return POLLERR;
1328                 if (channel->ops->is_finalized(channel->chan))
1329                         return POLLHUP;
1330                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1331                         return POLLIN | POLLRDNORM;
1332                 return 0;
1333         }
1334         return mask;
1335
1336 }
1337
1338 static
1339 int lttng_channel_release(struct inode *inode, struct file *file)
1340 {
1341         struct lttng_channel *channel = file->private_data;
1342
1343         if (channel)
1344                 fput(channel->session->file);
1345         return 0;
1346 }
1347
1348 static
1349 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1350 {
1351         struct lttng_channel *channel = file->private_data;
1352
1353         if (channel) {
1354                 fput(channel->session->file);
1355                 lttng_metadata_channel_destroy(channel);
1356         }
1357
1358         return 0;
1359 }
1360
1361 static const struct file_operations lttng_channel_fops = {
1362         .owner = THIS_MODULE,
1363         .release = lttng_channel_release,
1364         .poll = lttng_channel_poll,
1365         .unlocked_ioctl = lttng_channel_ioctl,
1366 #ifdef CONFIG_COMPAT
1367         .compat_ioctl = lttng_channel_ioctl,
1368 #endif
1369 };
1370
1371 static const struct file_operations lttng_metadata_fops = {
1372         .owner = THIS_MODULE,
1373         .release = lttng_metadata_channel_release,
1374         .unlocked_ioctl = lttng_metadata_ioctl,
1375 #ifdef CONFIG_COMPAT
1376         .compat_ioctl = lttng_metadata_ioctl,
1377 #endif
1378 };
1379
1380 /**
1381  *      lttng_event_ioctl - lttng syscall through ioctl
1382  *
1383  *      @file: the file
1384  *      @cmd: the command
1385  *      @arg: command arg
1386  *
1387  *      This ioctl implements lttng commands:
1388  *      LTTNG_KERNEL_CONTEXT
1389  *              Prepend a context field to each record of this event
1390  *      LTTNG_KERNEL_ENABLE
1391  *              Enable recording for this event (weak enable)
1392  *      LTTNG_KERNEL_DISABLE
1393  *              Disable recording for this event (strong disable)
1394  */
1395 static
1396 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1397 {
1398         struct lttng_event *event;
1399         struct lttng_enabler *enabler;
1400         enum lttng_event_type *evtype = file->private_data;
1401
1402         switch (cmd) {
1403         case LTTNG_KERNEL_OLD_CONTEXT:
1404         {
1405                 /* Not implemented */
1406                 return -ENOSYS;
1407         }
1408         case LTTNG_KERNEL_CONTEXT:
1409         {
1410                 /* Not implemented */
1411                 return -ENOSYS;
1412         }
1413         case LTTNG_KERNEL_OLD_ENABLE:
1414         case LTTNG_KERNEL_ENABLE:
1415                 switch (*evtype) {
1416                 case LTTNG_TYPE_EVENT:
1417                         event = file->private_data;
1418                         return lttng_event_enable(event);
1419                 case LTTNG_TYPE_ENABLER:
1420                         enabler = file->private_data;
1421                         return lttng_enabler_enable(enabler);
1422                 default:
1423                         WARN_ON_ONCE(1);
1424                         return -ENOSYS;
1425                 }
1426         case LTTNG_KERNEL_OLD_DISABLE:
1427         case LTTNG_KERNEL_DISABLE:
1428                 switch (*evtype) {
1429                 case LTTNG_TYPE_EVENT:
1430                         event = file->private_data;
1431                         return lttng_event_disable(event);
1432                 case LTTNG_TYPE_ENABLER:
1433                         enabler = file->private_data;
1434                         return lttng_enabler_disable(enabler);
1435                 default:
1436                         WARN_ON_ONCE(1);
1437                         return -ENOSYS;
1438                 }
1439         case LTTNG_KERNEL_FILTER:
1440                 switch (*evtype) {
1441                 case LTTNG_TYPE_EVENT:
1442                         return -EINVAL;
1443                 case LTTNG_TYPE_ENABLER:
1444                 {
1445                         enabler = file->private_data;
1446                         return lttng_enabler_attach_bytecode(enabler,
1447                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1448                 }
1449
1450                 }
1451         default:
1452                 return -ENOIOCTLCMD;
1453         }
1454 }
1455
1456 static
1457 int lttng_event_release(struct inode *inode, struct file *file)
1458 {
1459         struct lttng_event *event;
1460         struct lttng_enabler *enabler;
1461         enum lttng_event_type *evtype = file->private_data;
1462
1463         if (!evtype)
1464                 return 0;
1465
1466         switch (*evtype) {
1467         case LTTNG_TYPE_EVENT:
1468                 event = file->private_data;
1469                 if (event)
1470                         fput(event->chan->file);
1471                 break;
1472         case LTTNG_TYPE_ENABLER:
1473                 enabler = file->private_data;
1474                 if (enabler)
1475                         fput(enabler->chan->file);
1476                 break;
1477         default:
1478                 WARN_ON_ONCE(1);
1479                 break;
1480         }
1481
1482         return 0;
1483 }
1484
1485 /* TODO: filter control ioctl */
1486 static const struct file_operations lttng_event_fops = {
1487         .owner = THIS_MODULE,
1488         .release = lttng_event_release,
1489         .unlocked_ioctl = lttng_event_ioctl,
1490 #ifdef CONFIG_COMPAT
1491         .compat_ioctl = lttng_event_ioctl,
1492 #endif
1493 };
1494
1495 static int put_u64(uint64_t val, unsigned long arg)
1496 {
1497         return put_user(val, (uint64_t __user *) arg);
1498 }
1499
1500 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1501                 unsigned int cmd, unsigned long arg)
1502 {
1503         struct lib_ring_buffer *buf = filp->private_data;
1504         struct channel *chan = buf->backend.chan;
1505         const struct lib_ring_buffer_config *config = &chan->backend.config;
1506         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1507         int ret;
1508
1509         if (atomic_read(&chan->record_disabled))
1510                 return -EIO;
1511
1512         switch (cmd) {
1513         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1514         {
1515                 uint64_t ts;
1516
1517                 ret = ops->timestamp_begin(config, buf, &ts);
1518                 if (ret < 0)
1519                         goto error;
1520                 return put_u64(ts, arg);
1521         }
1522         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1523         {
1524                 uint64_t ts;
1525
1526                 ret = ops->timestamp_end(config, buf, &ts);
1527                 if (ret < 0)
1528                         goto error;
1529                 return put_u64(ts, arg);
1530         }
1531         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1532         {
1533                 uint64_t ed;
1534
1535                 ret = ops->events_discarded(config, buf, &ed);
1536                 if (ret < 0)
1537                         goto error;
1538                 return put_u64(ed, arg);
1539         }
1540         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1541         {
1542                 uint64_t cs;
1543
1544                 ret = ops->content_size(config, buf, &cs);
1545                 if (ret < 0)
1546                         goto error;
1547                 return put_u64(cs, arg);
1548         }
1549         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1550         {
1551                 uint64_t ps;
1552
1553                 ret = ops->packet_size(config, buf, &ps);
1554                 if (ret < 0)
1555                         goto error;
1556                 return put_u64(ps, arg);
1557         }
1558         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1559         {
1560                 uint64_t si;
1561
1562                 ret = ops->stream_id(config, buf, &si);
1563                 if (ret < 0)
1564                         goto error;
1565                 return put_u64(si, arg);
1566         }
1567         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1568         {
1569                 uint64_t ts;
1570
1571                 ret = ops->current_timestamp(config, buf, &ts);
1572                 if (ret < 0)
1573                         goto error;
1574                 return put_u64(ts, arg);
1575         }
1576         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1577         {
1578                 uint64_t seq;
1579
1580                 ret = ops->sequence_number(config, buf, &seq);
1581                 if (ret < 0)
1582                         goto error;
1583                 return put_u64(seq, arg);
1584         }
1585         case LTTNG_RING_BUFFER_INSTANCE_ID:
1586         {
1587                 uint64_t id;
1588
1589                 ret = ops->instance_id(config, buf, &id);
1590                 if (ret < 0)
1591                         goto error;
1592                 return put_u64(id, arg);
1593         }
1594         default:
1595                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1596                                 cmd, arg);
1597         }
1598
1599 error:
1600         return -ENOSYS;
1601 }
1602
1603 #ifdef CONFIG_COMPAT
1604 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1605                 unsigned int cmd, unsigned long arg)
1606 {
1607         struct lib_ring_buffer *buf = filp->private_data;
1608         struct channel *chan = buf->backend.chan;
1609         const struct lib_ring_buffer_config *config = &chan->backend.config;
1610         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1611         int ret;
1612
1613         if (atomic_read(&chan->record_disabled))
1614                 return -EIO;
1615
1616         switch (cmd) {
1617         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1618         {
1619                 uint64_t ts;
1620
1621                 ret = ops->timestamp_begin(config, buf, &ts);
1622                 if (ret < 0)
1623                         goto error;
1624                 return put_u64(ts, arg);
1625         }
1626         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1627         {
1628                 uint64_t ts;
1629
1630                 ret = ops->timestamp_end(config, buf, &ts);
1631                 if (ret < 0)
1632                         goto error;
1633                 return put_u64(ts, arg);
1634         }
1635         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1636         {
1637                 uint64_t ed;
1638
1639                 ret = ops->events_discarded(config, buf, &ed);
1640                 if (ret < 0)
1641                         goto error;
1642                 return put_u64(ed, arg);
1643         }
1644         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1645         {
1646                 uint64_t cs;
1647
1648                 ret = ops->content_size(config, buf, &cs);
1649                 if (ret < 0)
1650                         goto error;
1651                 return put_u64(cs, arg);
1652         }
1653         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1654         {
1655                 uint64_t ps;
1656
1657                 ret = ops->packet_size(config, buf, &ps);
1658                 if (ret < 0)
1659                         goto error;
1660                 return put_u64(ps, arg);
1661         }
1662         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1663         {
1664                 uint64_t si;
1665
1666                 ret = ops->stream_id(config, buf, &si);
1667                 if (ret < 0)
1668                         goto error;
1669                 return put_u64(si, arg);
1670         }
1671         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1672         {
1673                 uint64_t ts;
1674
1675                 ret = ops->current_timestamp(config, buf, &ts);
1676                 if (ret < 0)
1677                         goto error;
1678                 return put_u64(ts, arg);
1679         }
1680         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1681         {
1682                 uint64_t seq;
1683
1684                 ret = ops->sequence_number(config, buf, &seq);
1685                 if (ret < 0)
1686                         goto error;
1687                 return put_u64(seq, arg);
1688         }
1689         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1690         {
1691                 uint64_t id;
1692
1693                 ret = ops->instance_id(config, buf, &id);
1694                 if (ret < 0)
1695                         goto error;
1696                 return put_u64(id, arg);
1697         }
1698         default:
1699                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1700                                 cmd, arg);
1701         }
1702
1703 error:
1704         return -ENOSYS;
1705 }
1706 #endif /* CONFIG_COMPAT */
1707
1708 static void lttng_stream_override_ring_buffer_fops(void)
1709 {
1710         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1711         lttng_stream_ring_buffer_file_operations.open =
1712                 lib_ring_buffer_file_operations.open;
1713         lttng_stream_ring_buffer_file_operations.release =
1714                 lib_ring_buffer_file_operations.release;
1715         lttng_stream_ring_buffer_file_operations.poll =
1716                 lib_ring_buffer_file_operations.poll;
1717         lttng_stream_ring_buffer_file_operations.splice_read =
1718                 lib_ring_buffer_file_operations.splice_read;
1719         lttng_stream_ring_buffer_file_operations.mmap =
1720                 lib_ring_buffer_file_operations.mmap;
1721         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1722                 lttng_stream_ring_buffer_ioctl;
1723         lttng_stream_ring_buffer_file_operations.llseek =
1724                 lib_ring_buffer_file_operations.llseek;
1725 #ifdef CONFIG_COMPAT
1726         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1727                 lttng_stream_ring_buffer_compat_ioctl;
1728 #endif
1729 }
1730
1731 int __init lttng_abi_init(void)
1732 {
1733         int ret = 0;
1734
1735         wrapper_vmalloc_sync_all();
1736         lttng_clock_ref();
1737
1738         ret = lttng_tp_mempool_init();
1739         if (ret) {
1740                 goto error;
1741         }
1742
1743         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1744                                         &lttng_proc_ops, NULL);
1745
1746         if (!lttng_proc_dentry) {
1747                 printk(KERN_ERR "Error creating LTTng control file\n");
1748                 ret = -ENOMEM;
1749                 goto error;
1750         }
1751         lttng_stream_override_ring_buffer_fops();
1752         return 0;
1753
1754 error:
1755         lttng_tp_mempool_destroy();
1756         lttng_clock_unref();
1757         return ret;
1758 }
1759
1760 /* No __exit annotation because used by init error path too. */
1761 void lttng_abi_exit(void)
1762 {
1763         lttng_tp_mempool_destroy();
1764         lttng_clock_unref();
1765         if (lttng_proc_dentry)
1766                 remove_proc_entry("lttng", NULL);
1767 }