lttng-abi.c

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   2  *
   3  * lttng-abi.c
   4  *
   5  * LTTng ABI
   6  *
   7  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Mimic system calls for:
  10  * - session creation, returns a file descriptor or failure.
  11  *   - channel creation, returns a file descriptor or failure.
  12  *     - Operates on a session file descriptor
  13  *     - Takes all channel options as parameters.
  14  *   - stream get, returns a file descriptor or failure.
  15  *     - Operates on a channel file descriptor.
  16  *   - stream notifier get, returns a file descriptor or failure.
  17  *     - Operates on a channel file descriptor.
  18  *   - event creation, returns a file descriptor or failure.
  19  *     - Operates on a channel file descriptor
  20  *     - Takes an event name as parameter
  21  *     - Takes an instrumentation source as parameter
  22  *       - e.g. tracepoints, dynamic_probes...
  23  *     - Takes instrumentation source specific arguments.
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/anon_inodes.h>
  29 #include <linux/file.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/slab.h>
  32 #include <linux/err.h>
  33 #include <wrapper/vmalloc.h>    /* for wrapper_vmalloc_sync_mappings() */
  34 #include <wrapper/ringbuffer/vfs.h>
  35 #include <wrapper/ringbuffer/backend.h>
  36 #include <wrapper/ringbuffer/frontend.h>
  37 #include <wrapper/poll.h>
  38 #include <wrapper/file.h>
  39 #include <wrapper/kref.h>
  40 #include <lttng-string-utils.h>
  41 #include <lttng-abi.h>
  42 #include <lttng-abi-old.h>
  43 #include <lttng-events.h>
  44 #include <lttng-tracer.h>
  45 #include <lttng-tp-mempool.h>
  46 #include <lib/ringbuffer/frontend_types.h>
  47
  48 /*
  49  * This is LTTng's own personal way to create a system call as an external
  50  * module. We use ioctl() on /proc/lttng.
  51  */
  52
  53 static struct proc_dir_entry *lttng_proc_dentry;
  54
  55 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0))
  56 static const struct proc_ops lttng_proc_ops;
  57 #else
  58 static const struct file_operations lttng_proc_ops;
  59 #endif
  60
  61 static const struct file_operations lttng_session_fops;
  62 static const struct file_operations lttng_channel_fops;
  63 static const struct file_operations lttng_metadata_fops;
  64 static const struct file_operations lttng_event_fops;
  65 static struct file_operations lttng_stream_ring_buffer_file_operations;
  66
  67 static int put_u64(uint64_t val, unsigned long arg);
  68 static int put_u32(uint32_t val, unsigned long arg);
  69
  70 /*
  71  * Teardown management: opened file descriptors keep a refcount on the module,
  72  * so it can only exit when all file descriptors are closed.
  73  */
  74
  75 static
  76 int lttng_abi_create_session(void)
  77 {
  78         struct lttng_session *session;
  79         struct file *session_file;
  80         int session_fd, ret;
  81
  82         session = lttng_session_create();
  83         if (!session)
  84                 return -ENOMEM;
  85         session_fd = lttng_get_unused_fd();
  86         if (session_fd < 0) {
  87                 ret = session_fd;
  88                 goto fd_error;
  89         }
  90         session_file = anon_inode_getfile("[lttng_session]",
  91                                           &lttng_session_fops,
  92                                           session, O_RDWR);
  93         if (IS_ERR(session_file)) {
  94                 ret = PTR_ERR(session_file);
  95                 goto file_error;
  96         }
  97         session->file = session_file;
  98         fd_install(session_fd, session_file);
  99         return session_fd;
 100
 101 file_error:
 102         put_unused_fd(session_fd);
 103 fd_error:
 104         lttng_session_destroy(session);
 105         return ret;
 106 }
 107
 108 static
 109 int lttng_abi_tracepoint_list(void)
 110 {
 111         struct file *tracepoint_list_file;
 112         int file_fd, ret;
 113
 114         file_fd = lttng_get_unused_fd();
 115         if (file_fd < 0) {
 116                 ret = file_fd;
 117                 goto fd_error;
 118         }
 119
 120         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 121                                           &lttng_tracepoint_list_fops,
 122                                           NULL, O_RDWR);
 123         if (IS_ERR(tracepoint_list_file)) {
 124                 ret = PTR_ERR(tracepoint_list_file);
 125                 goto file_error;
 126         }
 127         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 128         if (ret < 0)
 129                 goto open_error;
 130         fd_install(file_fd, tracepoint_list_file);
 131         return file_fd;
 132
 133 open_error:
 134         fput(tracepoint_list_file);
 135 file_error:
 136         put_unused_fd(file_fd);
 137 fd_error:
 138         return ret;
 139 }
 140
 141 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 142 static inline
 143 int lttng_abi_syscall_list(void)
 144 {
 145         return -ENOSYS;
 146 }
 147 #else
 148 static
 149 int lttng_abi_syscall_list(void)
 150 {
 151         struct file *syscall_list_file;
 152         int file_fd, ret;
 153
 154         file_fd = lttng_get_unused_fd();
 155         if (file_fd < 0) {
 156                 ret = file_fd;
 157                 goto fd_error;
 158         }
 159
 160         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 161                                           &lttng_syscall_list_fops,
 162                                           NULL, O_RDWR);
 163         if (IS_ERR(syscall_list_file)) {
 164                 ret = PTR_ERR(syscall_list_file);
 165                 goto file_error;
 166         }
 167         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 168         if (ret < 0)
 169                 goto open_error;
 170         fd_install(file_fd, syscall_list_file);
 171         return file_fd;
 172
 173 open_error:
 174         fput(syscall_list_file);
 175 file_error:
 176         put_unused_fd(file_fd);
 177 fd_error:
 178         return ret;
 179 }
 180 #endif
 181
 182 static
 183 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 184 {
 185         v->major = LTTNG_MODULES_MAJOR_VERSION;
 186         v->minor = LTTNG_MODULES_MINOR_VERSION;
 187         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 188 }
 189
 190 static
 191 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 192 {
 193         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 194         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 195 }
 196
 197 static
 198 long lttng_abi_add_context(struct file *file,
 199         struct lttng_kernel_context *context_param,
 200         struct lttng_ctx **ctx, struct lttng_session *session)
 201 {
 202
 203         if (session->been_active)
 204                 return -EPERM;
 205
 206         switch (context_param->ctx) {
 207         case LTTNG_KERNEL_CONTEXT_PID:
 208                 return lttng_add_pid_to_ctx(ctx);
 209         case LTTNG_KERNEL_CONTEXT_PRIO:
 210                 return lttng_add_prio_to_ctx(ctx);
 211         case LTTNG_KERNEL_CONTEXT_NICE:
 212                 return lttng_add_nice_to_ctx(ctx);
 213         case LTTNG_KERNEL_CONTEXT_VPID:
 214                 return lttng_add_vpid_to_ctx(ctx);
 215         case LTTNG_KERNEL_CONTEXT_TID:
 216                 return lttng_add_tid_to_ctx(ctx);
 217         case LTTNG_KERNEL_CONTEXT_VTID:
 218                 return lttng_add_vtid_to_ctx(ctx);
 219         case LTTNG_KERNEL_CONTEXT_PPID:
 220                 return lttng_add_ppid_to_ctx(ctx);
 221         case LTTNG_KERNEL_CONTEXT_VPPID:
 222                 return lttng_add_vppid_to_ctx(ctx);
 223         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 224                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 225                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 226                                 context_param->u.perf_counter.config,
 227                                 context_param->u.perf_counter.name,
 228                                 ctx);
 229         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 230                 return lttng_add_procname_to_ctx(ctx);
 231         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 232                 return lttng_add_hostname_to_ctx(ctx);
 233         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 234                 return lttng_add_cpu_id_to_ctx(ctx);
 235         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 236                 return lttng_add_interruptible_to_ctx(ctx);
 237         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 238                 return lttng_add_need_reschedule_to_ctx(ctx);
 239         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 240                 return lttng_add_preemptible_to_ctx(ctx);
 241         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 242                 return lttng_add_migratable_to_ctx(ctx);
 243         case LTTNG_KERNEL_CONTEXT_CALLSTACK_KERNEL:
 244         case LTTNG_KERNEL_CONTEXT_CALLSTACK_USER:
 245                 return lttng_add_callstack_to_ctx(ctx, context_param->ctx);
 246         default:
 247                 return -EINVAL;
 248         }
 249 }
 250
 251 /**
 252  *      lttng_ioctl - lttng syscall through ioctl
 253  *
 254  *      @file: the file
 255  *      @cmd: the command
 256  *      @arg: command arg
 257  *
 258  *      This ioctl implements lttng commands:
 259  *      LTTNG_KERNEL_SESSION
 260  *              Returns a LTTng trace session file descriptor
 261  *      LTTNG_KERNEL_TRACER_VERSION
 262  *              Returns the LTTng kernel tracer version
 263  *      LTTNG_KERNEL_TRACEPOINT_LIST
 264  *              Returns a file descriptor listing available tracepoints
 265  *      LTTNG_KERNEL_WAIT_QUIESCENT
 266  *              Returns after all previously running probes have completed
 267  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 268  *              Returns the LTTng kernel tracer ABI version
 269  *
 270  * The returned session will be deleted when its file descriptor is closed.
 271  */
 272 static
 273 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 274 {
 275         switch (cmd) {
 276         case LTTNG_KERNEL_OLD_SESSION:
 277         case LTTNG_KERNEL_SESSION:
 278                 return lttng_abi_create_session();
 279         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 280         {
 281                 struct lttng_kernel_tracer_version v;
 282                 struct lttng_kernel_old_tracer_version oldv;
 283                 struct lttng_kernel_old_tracer_version *uversion =
 284                         (struct lttng_kernel_old_tracer_version __user *) arg;
 285
 286                 lttng_abi_tracer_version(&v);
 287                 oldv.major = v.major;
 288                 oldv.minor = v.minor;
 289                 oldv.patchlevel = v.patchlevel;
 290
 291                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 292                         return -EFAULT;
 293                 return 0;
 294         }
 295         case LTTNG_KERNEL_TRACER_VERSION:
 296         {
 297                 struct lttng_kernel_tracer_version version;
 298                 struct lttng_kernel_tracer_version *uversion =
 299                         (struct lttng_kernel_tracer_version __user *) arg;
 300
 301                 lttng_abi_tracer_version(&version);
 302
 303                 if (copy_to_user(uversion, &version, sizeof(version)))
 304                         return -EFAULT;
 305                 return 0;
 306         }
 307         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 308         {
 309                 struct lttng_kernel_tracer_abi_version version;
 310                 struct lttng_kernel_tracer_abi_version *uversion =
 311                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 312
 313                 lttng_abi_tracer_abi_version(&version);
 314
 315                 if (copy_to_user(uversion, &version, sizeof(version)))
 316                         return -EFAULT;
 317                 return 0;
 318         }
 319         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 320         case LTTNG_KERNEL_TRACEPOINT_LIST:
 321                 return lttng_abi_tracepoint_list();
 322         case LTTNG_KERNEL_SYSCALL_LIST:
 323                 return lttng_abi_syscall_list();
 324         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 325         case LTTNG_KERNEL_WAIT_QUIESCENT:
 326                 synchronize_trace();
 327                 return 0;
 328         case LTTNG_KERNEL_OLD_CALIBRATE:
 329         {
 330                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 331                         (struct lttng_kernel_old_calibrate __user *) arg;
 332                 struct lttng_kernel_old_calibrate old_calibrate;
 333                 struct lttng_kernel_calibrate calibrate;
 334                 int ret;
 335
 336                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 337                         return -EFAULT;
 338                 calibrate.type = old_calibrate.type;
 339                 ret = lttng_calibrate(&calibrate);
 340                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 341                         return -EFAULT;
 342                 return ret;
 343         }
 344         case LTTNG_KERNEL_CALIBRATE:
 345         {
 346                 struct lttng_kernel_calibrate __user *ucalibrate =
 347                         (struct lttng_kernel_calibrate __user *) arg;
 348                 struct lttng_kernel_calibrate calibrate;
 349                 int ret;
 350
 351                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 352                         return -EFAULT;
 353                 ret = lttng_calibrate(&calibrate);
 354                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 355                         return -EFAULT;
 356                 return ret;
 357         }
 358         default:
 359                 return -ENOIOCTLCMD;
 360         }
 361 }
 362
 363 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0))
 364 static const struct proc_ops lttng_proc_ops = {
 365         .proc_ioctl = lttng_ioctl,
 366 #ifdef CONFIG_COMPAT
 367         .proc_compat_ioctl = lttng_ioctl,
 368 #endif /* CONFIG_COMPAT */
 369 };
 370 #else
 371 static const struct file_operations lttng_proc_ops = {
 372         .owner = THIS_MODULE,
 373         .unlocked_ioctl = lttng_ioctl,
 374 #ifdef CONFIG_COMPAT
 375         .compat_ioctl = lttng_ioctl,
 376 #endif /* CONFIG_COMPAT */
 377 };
 378 #endif
 379
 380 static
 381 int lttng_abi_create_channel(struct file *session_file,
 382                              struct lttng_kernel_channel *chan_param,
 383                              enum channel_type channel_type)
 384 {
 385         struct lttng_session *session = session_file->private_data;
 386         const struct file_operations *fops = NULL;
 387         const char *transport_name;
 388         struct lttng_channel *chan;
 389         struct file *chan_file;
 390         int chan_fd;
 391         int ret = 0;
 392
 393         chan_fd = lttng_get_unused_fd();
 394         if (chan_fd < 0) {
 395                 ret = chan_fd;
 396                 goto fd_error;
 397         }
 398         switch (channel_type) {
 399         case PER_CPU_CHANNEL:
 400                 fops = &lttng_channel_fops;
 401                 break;
 402         case METADATA_CHANNEL:
 403                 fops = &lttng_metadata_fops;
 404                 break;
 405         }
 406
 407         chan_file = anon_inode_getfile("[lttng_channel]",
 408                                        fops,
 409                                        NULL, O_RDWR);
 410         if (IS_ERR(chan_file)) {
 411                 ret = PTR_ERR(chan_file);
 412                 goto file_error;
 413         }
 414         switch (channel_type) {
 415         case PER_CPU_CHANNEL:
 416                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 417                         transport_name = chan_param->overwrite ?
 418                                 "relay-overwrite" : "relay-discard";
 419                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 420                         transport_name = chan_param->overwrite ?
 421                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 422                 } else {
 423                         return -EINVAL;
 424                 }
 425                 break;
 426         case METADATA_CHANNEL:
 427                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 428                         transport_name = "relay-metadata";
 429                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 430                         transport_name = "relay-metadata-mmap";
 431                 else
 432                         return -EINVAL;
 433                 break;
 434         default:
 435                 transport_name = "<unknown>";
 436                 break;
 437         }
 438         if (!atomic_long_add_unless(&session_file->f_count, 1, LONG_MAX)) {
 439                 ret = -EOVERFLOW;
 440                 goto refcount_error;
 441         }
 442         /*
 443          * We tolerate no failure path after channel creation. It will stay
 444          * invariant for the rest of the session.
 445          */
 446         chan = lttng_channel_create(session, transport_name, NULL,
 447                                   chan_param->subbuf_size,
 448                                   chan_param->num_subbuf,
 449                                   chan_param->switch_timer_interval,
 450                                   chan_param->read_timer_interval,
 451                                   channel_type);
 452         if (!chan) {
 453                 ret = -EINVAL;
 454                 goto chan_error;
 455         }
 456         chan->file = chan_file;
 457         chan_file->private_data = chan;
 458         fd_install(chan_fd, chan_file);
 459
 460         return chan_fd;
 461
 462 chan_error:
 463         atomic_long_dec(&session_file->f_count);
 464 refcount_error:
 465         fput(chan_file);
 466 file_error:
 467         put_unused_fd(chan_fd);
 468 fd_error:
 469         return ret;
 470 }
 471
 472 static
 473 int lttng_abi_session_set_name(struct lttng_session *session,
 474                 struct lttng_kernel_session_name *name)
 475 {
 476         size_t len;
 477
 478         len = strnlen(name->name, LTTNG_KERNEL_SESSION_NAME_LEN);
 479
 480         if (len == LTTNG_KERNEL_SESSION_NAME_LEN) {
 481                 /* Name is too long/malformed */
 482                 return -EINVAL;
 483         }
 484
 485         strcpy(session->name, name->name);
 486         return 0;
 487 }
 488
 489 static
 490 int lttng_abi_session_set_creation_time(struct lttng_session *session,
 491                 struct lttng_kernel_session_creation_time *time)
 492 {
 493         size_t len;
 494
 495         len = strnlen(time->iso8601, LTTNG_KERNEL_SESSION_CREATION_TIME_ISO8601_LEN);
 496
 497         if (len == LTTNG_KERNEL_SESSION_CREATION_TIME_ISO8601_LEN) {
 498                 /* Time is too long/malformed */
 499                 return -EINVAL;
 500         }
 501
 502         strcpy(session->creation_time, time->iso8601);
 503         return 0;
 504 }
 505
 506 /**
 507  *      lttng_session_ioctl - lttng session fd ioctl
 508  *
 509  *      @file: the file
 510  *      @cmd: the command
 511  *      @arg: command arg
 512  *
 513  *      This ioctl implements lttng commands:
 514  *      LTTNG_KERNEL_CHANNEL
 515  *              Returns a LTTng channel file descriptor
 516  *      LTTNG_KERNEL_ENABLE
 517  *              Enables tracing for a session (weak enable)
 518  *      LTTNG_KERNEL_DISABLE
 519  *              Disables tracing for a session (strong disable)
 520  *      LTTNG_KERNEL_METADATA
 521  *              Returns a LTTng metadata file descriptor
 522  *      LTTNG_KERNEL_SESSION_TRACK_PID
 523  *              Add PID to session tracker
 524  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 525  *              Remove PID from session tracker
 526  *
 527  * The returned channel will be deleted when its file descriptor is closed.
 528  */
 529 static
 530 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 531 {
 532         struct lttng_session *session = file->private_data;
 533         struct lttng_kernel_channel chan_param;
 534         struct lttng_kernel_old_channel old_chan_param;
 535
 536         switch (cmd) {
 537         case LTTNG_KERNEL_OLD_CHANNEL:
 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                                 PER_CPU_CHANNEL);
 552         }
 553         case LTTNG_KERNEL_CHANNEL:
 554         {
 555                 if (copy_from_user(&chan_param,
 556                                 (struct lttng_kernel_channel __user *) arg,
 557                                 sizeof(struct lttng_kernel_channel)))
 558                         return -EFAULT;
 559                 return lttng_abi_create_channel(file, &chan_param,
 560                                 PER_CPU_CHANNEL);
 561         }
 562         case LTTNG_KERNEL_OLD_SESSION_START:
 563         case LTTNG_KERNEL_OLD_ENABLE:
 564         case LTTNG_KERNEL_SESSION_START:
 565         case LTTNG_KERNEL_ENABLE:
 566                 return lttng_session_enable(session);
 567         case LTTNG_KERNEL_OLD_SESSION_STOP:
 568         case LTTNG_KERNEL_OLD_DISABLE:
 569         case LTTNG_KERNEL_SESSION_STOP:
 570         case LTTNG_KERNEL_DISABLE:
 571                 return lttng_session_disable(session);
 572         case LTTNG_KERNEL_OLD_METADATA:
 573         {
 574                 if (copy_from_user(&old_chan_param,
 575                                 (struct lttng_kernel_old_channel __user *) arg,
 576                                 sizeof(struct lttng_kernel_old_channel)))
 577                         return -EFAULT;
 578                 chan_param.overwrite = old_chan_param.overwrite;
 579                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 580                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 581                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 582                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 583                 chan_param.output = old_chan_param.output;
 584
 585                 return lttng_abi_create_channel(file, &chan_param,
 586                                 METADATA_CHANNEL);
 587         }
 588         case LTTNG_KERNEL_METADATA:
 589         {
 590                 if (copy_from_user(&chan_param,
 591                                         (struct lttng_kernel_channel __user *) arg,
 592                                         sizeof(struct lttng_kernel_channel)))
 593                         return -EFAULT;
 594                 return lttng_abi_create_channel(file, &chan_param,
 595                                 METADATA_CHANNEL);
 596         }
 597         case LTTNG_KERNEL_SESSION_TRACK_PID:
 598                 return lttng_session_track_pid(session, (int) arg);
 599         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 600                 return lttng_session_untrack_pid(session, (int) arg);
 601         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 602                 return lttng_session_list_tracker_pids(session);
 603         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 604                 return lttng_session_metadata_regenerate(session);
 605         case LTTNG_KERNEL_SESSION_STATEDUMP:
 606                 return lttng_session_statedump(session);
 607         case LTTNG_KERNEL_SESSION_SET_NAME:
 608         {
 609                 struct lttng_kernel_session_name name;
 610
 611                 if (copy_from_user(&name,
 612                                 (struct lttng_kernel_session_name __user *) arg,
 613                                 sizeof(struct lttng_kernel_session_name)))
 614                         return -EFAULT;
 615                 return lttng_abi_session_set_name(session, &name);
 616         }
 617         case LTTNG_KERNEL_SESSION_SET_CREATION_TIME:
 618         {
 619                 struct lttng_kernel_session_creation_time time;
 620
 621                 if (copy_from_user(&time,
 622                                 (struct lttng_kernel_session_creation_time __user *) arg,
 623                                 sizeof(struct lttng_kernel_session_creation_time)))
 624                         return -EFAULT;
 625                 return lttng_abi_session_set_creation_time(session, &time);
 626         }
 627         default:
 628                 return -ENOIOCTLCMD;
 629         }
 630 }
 631
 632 /*
 633  * Called when the last file reference is dropped.
 634  *
 635  * Big fat note: channels and events are invariant for the whole session after
 636  * their creation. So this session destruction also destroys all channel and
 637  * event structures specific to this session (they are not destroyed when their
 638  * individual file is released).
 639  */
 640 static
 641 int lttng_session_release(struct inode *inode, struct file *file)
 642 {
 643         struct lttng_session *session = file->private_data;
 644
 645         if (session)
 646                 lttng_session_destroy(session);
 647         return 0;
 648 }
 649
 650 static const struct file_operations lttng_session_fops = {
 651         .owner = THIS_MODULE,
 652         .release = lttng_session_release,
 653         .unlocked_ioctl = lttng_session_ioctl,
 654 #ifdef CONFIG_COMPAT
 655         .compat_ioctl = lttng_session_ioctl,
 656 #endif
 657 };
 658
 659 /**
 660  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 661  *      @filp: the file
 662  *      @wait: poll table
 663  *
 664  *      Handles the poll operations for the metadata channels.
 665  */
 666 static
 667 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 668                 poll_table *wait)
 669 {
 670         struct lttng_metadata_stream *stream = filp->private_data;
 671         struct lib_ring_buffer *buf = stream->priv;
 672         int finalized;
 673         unsigned int mask = 0;
 674
 675         if (filp->f_mode & FMODE_READ) {
 676                 poll_wait_set_exclusive(wait);
 677                 poll_wait(filp, &stream->read_wait, wait);
 678
 679                 finalized = stream->finalized;
 680
 681                 /*
 682                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 683                  * ordering finalized load before offsets loads.
 684                  */
 685                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 686
 687                 if (finalized)
 688                         mask |= POLLHUP;
 689
 690                 mutex_lock(&stream->metadata_cache->lock);
 691                 if (stream->metadata_cache->metadata_written >
 692                                 stream->metadata_out)
 693                         mask |= POLLIN;
 694                 mutex_unlock(&stream->metadata_cache->lock);
 695         }
 696
 697         return mask;
 698 }
 699
 700 static
 701 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 702                 unsigned int cmd, unsigned long arg)
 703 {
 704         struct lttng_metadata_stream *stream = filp->private_data;
 705
 706         stream->metadata_out = stream->metadata_in;
 707 }
 708
 709 /*
 710  * Reset the counter of how much metadata has been consumed to 0. That way,
 711  * the consumer receives the content of the metadata cache unchanged. This is
 712  * different from the metadata_regenerate where the offset from epoch is
 713  * resampled, here we want the exact same content as the last time the metadata
 714  * was generated. This command is only possible if all the metadata written
 715  * in the cache has been output to the metadata stream to avoid corrupting the
 716  * metadata file.
 717  *
 718  * Return 0 on success, a negative value on error.
 719  */
 720 static
 721 int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
 722 {
 723         int ret;
 724         struct lttng_metadata_cache *cache = stream->metadata_cache;
 725
 726         mutex_lock(&cache->lock);
 727         if (stream->metadata_out != cache->metadata_written) {
 728                 ret = -EBUSY;
 729                 goto end;
 730         }
 731         stream->metadata_out = 0;
 732         stream->metadata_in = 0;
 733         wake_up_interruptible(&stream->read_wait);
 734         ret = 0;
 735
 736 end:
 737         mutex_unlock(&cache->lock);
 738         return ret;
 739 }
 740
 741 static
 742 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 743                 unsigned int cmd, unsigned long arg)
 744 {
 745         int ret;
 746         struct lttng_metadata_stream *stream = filp->private_data;
 747         struct lib_ring_buffer *buf = stream->priv;
 748         unsigned int rb_cmd;
 749         bool coherent;
 750
 751         if (cmd == RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK)
 752                 rb_cmd = RING_BUFFER_GET_NEXT_SUBBUF;
 753         else
 754                 rb_cmd = cmd;
 755
 756         switch (cmd) {
 757         case RING_BUFFER_GET_NEXT_SUBBUF:
 758         {
 759                 struct lttng_metadata_stream *stream = filp->private_data;
 760                 struct lib_ring_buffer *buf = stream->priv;
 761                 struct channel *chan = buf->backend.chan;
 762
 763                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 764                 if (ret > 0) {
 765                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 766                         ret = 0;
 767                 } else if (ret < 0)
 768                         goto err;
 769                 break;
 770         }
 771         case RING_BUFFER_GET_SUBBUF:
 772         {
 773                 /*
 774                  * Random access is not allowed for metadata channel.
 775                  */
 776                 return -ENOSYS;
 777         }
 778         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 779         case RING_BUFFER_FLUSH:
 780         {
 781                 struct lttng_metadata_stream *stream = filp->private_data;
 782                 struct lib_ring_buffer *buf = stream->priv;
 783                 struct channel *chan = buf->backend.chan;
 784
 785                 /*
 786                  * Before doing the actual ring buffer flush, write up to one
 787                  * packet of metadata in the ring buffer.
 788                  */
 789                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 790                 if (ret < 0)
 791                         goto err;
 792                 break;
 793         }
 794         case RING_BUFFER_GET_METADATA_VERSION:
 795         {
 796                 struct lttng_metadata_stream *stream = filp->private_data;
 797
 798                 return put_u64(stream->version, arg);
 799         }
 800         case RING_BUFFER_METADATA_CACHE_DUMP:
 801         {
 802                 struct lttng_metadata_stream *stream = filp->private_data;
 803
 804                 return lttng_metadata_cache_dump(stream);
 805         }
 806         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
 807         {
 808                 struct lttng_metadata_stream *stream = filp->private_data;
 809                 struct lib_ring_buffer *buf = stream->priv;
 810                 struct channel *chan = buf->backend.chan;
 811
 812                 ret = lttng_metadata_output_channel(stream, chan, &coherent);
 813                 if (ret > 0) {
 814                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 815                         ret = 0;
 816                 } else if (ret < 0) {
 817                         goto err;
 818                 }
 819                 break;
 820         }
 821         default:
 822                 break;
 823         }
 824         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 825
 826         /* Performing lib ring buffer ioctl after our own. */
 827         ret = lib_ring_buffer_ioctl(filp, rb_cmd, arg, buf);
 828         if (ret < 0)
 829                 goto err;
 830
 831         switch (cmd) {
 832         case RING_BUFFER_PUT_NEXT_SUBBUF:
 833         {
 834                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 835                                 cmd, arg);
 836                 break;
 837         }
 838         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
 839         {
 840                 return put_u32(coherent, arg);
 841         }
 842         default:
 843                 break;
 844         }
 845 err:
 846         return ret;
 847 }
 848
 849 #ifdef CONFIG_COMPAT
 850 static
 851 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 852                 unsigned int cmd, unsigned long arg)
 853 {
 854         int ret;
 855         struct lttng_metadata_stream *stream = filp->private_data;
 856         struct lib_ring_buffer *buf = stream->priv;
 857         unsigned int rb_cmd;
 858         bool coherent;
 859
 860         if (cmd == RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK)
 861                 rb_cmd = RING_BUFFER_GET_NEXT_SUBBUF;
 862         else
 863                 rb_cmd = cmd;
 864
 865         switch (cmd) {
 866         case RING_BUFFER_GET_NEXT_SUBBUF:
 867         {
 868                 struct lttng_metadata_stream *stream = filp->private_data;
 869                 struct lib_ring_buffer *buf = stream->priv;
 870                 struct channel *chan = buf->backend.chan;
 871
 872                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 873                 if (ret > 0) {
 874                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 875                         ret = 0;
 876                 } else if (ret < 0)
 877                         goto err;
 878                 break;
 879         }
 880         case RING_BUFFER_GET_SUBBUF:
 881         {
 882                 /*
 883                  * Random access is not allowed for metadata channel.
 884                  */
 885                 return -ENOSYS;
 886         }
 887         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 888         case RING_BUFFER_FLUSH:
 889         {
 890                 struct lttng_metadata_stream *stream = filp->private_data;
 891                 struct lib_ring_buffer *buf = stream->priv;
 892                 struct channel *chan = buf->backend.chan;
 893
 894                 /*
 895                  * Before doing the actual ring buffer flush, write up to one
 896                  * packet of metadata in the ring buffer.
 897                  */
 898                 ret = lttng_metadata_output_channel(stream, chan, NULL);
 899                 if (ret < 0)
 900                         goto err;
 901                 break;
 902         }
 903         case RING_BUFFER_GET_METADATA_VERSION:
 904         {
 905                 struct lttng_metadata_stream *stream = filp->private_data;
 906
 907                 return put_u64(stream->version, arg);
 908         }
 909         case RING_BUFFER_METADATA_CACHE_DUMP:
 910         {
 911                 struct lttng_metadata_stream *stream = filp->private_data;
 912
 913                 return lttng_metadata_cache_dump(stream);
 914         }
 915         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
 916         {
 917                 struct lttng_metadata_stream *stream = filp->private_data;
 918                 struct lib_ring_buffer *buf = stream->priv;
 919                 struct channel *chan = buf->backend.chan;
 920
 921                 ret = lttng_metadata_output_channel(stream, chan, &coherent);
 922                 if (ret > 0) {
 923                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 924                         ret = 0;
 925                 } else if (ret < 0) {
 926                         goto err;
 927                 }
 928                 break;
 929         }
 930         default:
 931                 break;
 932         }
 933         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 934
 935         /* Performing lib ring buffer ioctl after our own. */
 936         ret = lib_ring_buffer_compat_ioctl(filp, rb_cmd, arg, buf);
 937         if (ret < 0)
 938                 goto err;
 939
 940         switch (cmd) {
 941         case RING_BUFFER_PUT_NEXT_SUBBUF:
 942         {
 943                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 944                                 cmd, arg);
 945                 break;
 946         }
 947         case RING_BUFFER_GET_NEXT_SUBBUF_METADATA_CHECK:
 948         {
 949                 return put_u32(coherent, arg);
 950         }
 951         default:
 952                 break;
 953         }
 954 err:
 955         return ret;
 956 }
 957 #endif
 958
 959 /*
 960  * This is not used by anonymous file descriptors. This code is left
 961  * there if we ever want to implement an inode with open() operation.
 962  */
 963 static
 964 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 965 {
 966         struct lttng_metadata_stream *stream = inode->i_private;
 967         struct lib_ring_buffer *buf = stream->priv;
 968
 969         file->private_data = buf;
 970         /*
 971          * Since life-time of metadata cache differs from that of
 972          * session, we need to keep our own reference on the transport.
 973          */
 974         if (!try_module_get(stream->transport->owner)) {
 975                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 976                 return -EBUSY;
 977         }
 978         return lib_ring_buffer_open(inode, file, buf);
 979 }
 980
 981 static
 982 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 983 {
 984         struct lttng_metadata_stream *stream = file->private_data;
 985         struct lib_ring_buffer *buf = stream->priv;
 986
 987         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 988         module_put(stream->transport->owner);
 989         return lib_ring_buffer_release(inode, file, buf);
 990 }
 991
 992 static
 993 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 994                 struct pipe_inode_info *pipe, size_t len,
 995                 unsigned int flags)
 996 {
 997         struct lttng_metadata_stream *stream = in->private_data;
 998         struct lib_ring_buffer *buf = stream->priv;
 999
1000         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
1001                         flags, buf);
1002 }
1003
1004 static
1005 int lttng_metadata_ring_buffer_mmap(struct file *filp,
1006                 struct vm_area_struct *vma)
1007 {
1008         struct lttng_metadata_stream *stream = filp->private_data;
1009         struct lib_ring_buffer *buf = stream->priv;
1010
1011         return lib_ring_buffer_mmap(filp, vma, buf);
1012 }
1013
1014 static
1015 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
1016         .owner = THIS_MODULE,
1017         .open = lttng_metadata_ring_buffer_open,
1018         .release = lttng_metadata_ring_buffer_release,
1019         .poll = lttng_metadata_ring_buffer_poll,
1020         .splice_read = lttng_metadata_ring_buffer_splice_read,
1021         .mmap = lttng_metadata_ring_buffer_mmap,
1022         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
1023         .llseek = vfs_lib_ring_buffer_no_llseek,
1024 #ifdef CONFIG_COMPAT
1025         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
1026 #endif
1027 };
1028
1029 static
1030 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
1031                 const struct file_operations *fops)
1032 {
1033         int stream_fd, ret;
1034         struct file *stream_file;
1035
1036         stream_fd = lttng_get_unused_fd();
1037         if (stream_fd < 0) {
1038                 ret = stream_fd;
1039                 goto fd_error;
1040         }
1041         stream_file = anon_inode_getfile("[lttng_stream]", fops,
1042                         stream_priv, O_RDWR);
1043         if (IS_ERR(stream_file)) {
1044                 ret = PTR_ERR(stream_file);
1045                 goto file_error;
1046         }
1047         /*
1048          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
1049          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
1050          * file descriptor, so we set FMODE_PREAD here.
1051          */
1052         stream_file->f_mode |= FMODE_PREAD;
1053         fd_install(stream_fd, stream_file);
1054         /*
1055          * The stream holds a reference to the channel within the generic ring
1056          * buffer library, so no need to hold a refcount on the channel and
1057          * session files here.
1058          */
1059         return stream_fd;
1060
1061 file_error:
1062         put_unused_fd(stream_fd);
1063 fd_error:
1064         return ret;
1065 }
1066
1067 static
1068 int lttng_abi_open_stream(struct file *channel_file)
1069 {
1070         struct lttng_channel *channel = channel_file->private_data;
1071         struct lib_ring_buffer *buf;
1072         int ret;
1073         void *stream_priv;
1074
1075         buf = channel->ops->buffer_read_open(channel->chan);
1076         if (!buf)
1077                 return -ENOENT;
1078
1079         stream_priv = buf;
1080         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1081                         &lttng_stream_ring_buffer_file_operations);
1082         if (ret < 0)
1083                 goto fd_error;
1084
1085         return ret;
1086
1087 fd_error:
1088         channel->ops->buffer_read_close(buf);
1089         return ret;
1090 }
1091
1092 static
1093 int lttng_abi_open_metadata_stream(struct file *channel_file)
1094 {
1095         struct lttng_channel *channel = channel_file->private_data;
1096         struct lttng_session *session = channel->session;
1097         struct lib_ring_buffer *buf;
1098         int ret;
1099         struct lttng_metadata_stream *metadata_stream;
1100         void *stream_priv;
1101
1102         buf = channel->ops->buffer_read_open(channel->chan);
1103         if (!buf)
1104                 return -ENOENT;
1105
1106         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
1107                         GFP_KERNEL);
1108         if (!metadata_stream) {
1109                 ret = -ENOMEM;
1110                 goto nomem;
1111         }
1112         metadata_stream->metadata_cache = session->metadata_cache;
1113         init_waitqueue_head(&metadata_stream->read_wait);
1114         metadata_stream->priv = buf;
1115         stream_priv = metadata_stream;
1116         metadata_stream->transport = channel->transport;
1117         /* Initial state is an empty metadata, considered as incoherent. */
1118         metadata_stream->coherent = false;
1119
1120         /*
1121          * Since life-time of metadata cache differs from that of
1122          * session, we need to keep our own reference on the transport.
1123          */
1124         if (!try_module_get(metadata_stream->transport->owner)) {
1125                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
1126                 ret = -EINVAL;
1127                 goto notransport;
1128         }
1129
1130         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1131                 ret = -EOVERFLOW;
1132                 goto kref_error;
1133         }
1134
1135         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1136                         &lttng_metadata_ring_buffer_file_operations);
1137         if (ret < 0)
1138                 goto fd_error;
1139
1140         list_add(&metadata_stream->list,
1141                 &session->metadata_cache->metadata_stream);
1142         return ret;
1143
1144 fd_error:
1145         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1146 kref_error:
1147         module_put(metadata_stream->transport->owner);
1148 notransport:
1149         kfree(metadata_stream);
1150 nomem:
1151         channel->ops->buffer_read_close(buf);
1152         return ret;
1153 }
1154
1155 static
1156 int lttng_abi_create_event(struct file *channel_file,
1157                            struct lttng_kernel_event *event_param)
1158 {
1159         struct lttng_channel *channel = channel_file->private_data;
1160         int event_fd, ret;
1161         struct file *event_file;
1162         void *priv;
1163
1164         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1165         switch (event_param->instrumentation) {
1166         case LTTNG_KERNEL_KRETPROBE:
1167                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1168                 break;
1169         case LTTNG_KERNEL_KPROBE:
1170                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1171                 break;
1172         case LTTNG_KERNEL_FUNCTION:
1173                 WARN_ON_ONCE(1);
1174                 /* Not implemented. */
1175                 break;
1176         default:
1177                 break;
1178         }
1179         event_fd = lttng_get_unused_fd();
1180         if (event_fd < 0) {
1181                 ret = event_fd;
1182                 goto fd_error;
1183         }
1184         event_file = anon_inode_getfile("[lttng_event]",
1185                                         &lttng_event_fops,
1186                                         NULL, O_RDWR);
1187         if (IS_ERR(event_file)) {
1188                 ret = PTR_ERR(event_file);
1189                 goto file_error;
1190         }
1191         /* The event holds a reference on the channel */
1192         if (!atomic_long_add_unless(&channel_file->f_count, 1, LONG_MAX)) {
1193                 ret = -EOVERFLOW;
1194                 goto refcount_error;
1195         }
1196         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1197                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1198                 struct lttng_enabler *enabler;
1199
1200                 if (strutils_is_star_glob_pattern(event_param->name)) {
1201                         /*
1202                          * If the event name is a star globbing pattern,
1203                          * we create the special star globbing enabler.
1204                          */
1205                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1206                                 event_param, channel);
1207                 } else {
1208                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1209                                 event_param, channel);
1210                 }
1211                 priv = enabler;
1212         } else {
1213                 struct lttng_event *event;
1214
1215                 /*
1216                  * We tolerate no failure path after event creation. It
1217                  * will stay invariant for the rest of the session.
1218                  */
1219                 event = lttng_event_create(channel, event_param,
1220                                 NULL, NULL,
1221                                 event_param->instrumentation);
1222                 WARN_ON_ONCE(!event);
1223                 if (IS_ERR(event)) {
1224                         ret = PTR_ERR(event);
1225                         goto event_error;
1226                 }
1227                 priv = event;
1228         }
1229         event_file->private_data = priv;
1230         fd_install(event_fd, event_file);
1231         return event_fd;
1232
1233 event_error:
1234         atomic_long_dec(&channel_file->f_count);
1235 refcount_error:
1236         fput(event_file);
1237 file_error:
1238         put_unused_fd(event_fd);
1239 fd_error:
1240         return ret;
1241 }
1242
1243 /**
1244  *      lttng_channel_ioctl - lttng syscall through ioctl
1245  *
1246  *      @file: the file
1247  *      @cmd: the command
1248  *      @arg: command arg
1249  *
1250  *      This ioctl implements lttng commands:
1251  *      LTTNG_KERNEL_STREAM
1252  *              Returns an event stream file descriptor or failure.
1253  *              (typically, one event stream records events from one CPU)
1254  *      LTTNG_KERNEL_EVENT
1255  *              Returns an event file descriptor or failure.
1256  *      LTTNG_KERNEL_CONTEXT
1257  *              Prepend a context field to each event in the channel
1258  *      LTTNG_KERNEL_ENABLE
1259  *              Enable recording for events in this channel (weak enable)
1260  *      LTTNG_KERNEL_DISABLE
1261  *              Disable recording for events in this channel (strong disable)
1262  *
1263  * Channel and event file descriptors also hold a reference on the session.
1264  */
1265 static
1266 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1267 {
1268         struct lttng_channel *channel = file->private_data;
1269
1270         switch (cmd) {
1271         case LTTNG_KERNEL_OLD_STREAM:
1272         case LTTNG_KERNEL_STREAM:
1273                 return lttng_abi_open_stream(file);
1274         case LTTNG_KERNEL_OLD_EVENT:
1275         {
1276                 struct lttng_kernel_event *uevent_param;
1277                 struct lttng_kernel_old_event *old_uevent_param;
1278                 int ret;
1279
1280                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1281                                 GFP_KERNEL);
1282                 if (!uevent_param) {
1283                         ret = -ENOMEM;
1284                         goto old_event_end;
1285                 }
1286                 old_uevent_param = kmalloc(
1287                                 sizeof(struct lttng_kernel_old_event),
1288                                 GFP_KERNEL);
1289                 if (!old_uevent_param) {
1290                         ret = -ENOMEM;
1291                         goto old_event_error_free_param;
1292                 }
1293                 if (copy_from_user(old_uevent_param,
1294                                 (struct lttng_kernel_old_event __user *) arg,
1295                                 sizeof(struct lttng_kernel_old_event))) {
1296                         ret = -EFAULT;
1297                         goto old_event_error_free_old_param;
1298                 }
1299
1300                 memcpy(uevent_param->name, old_uevent_param->name,
1301                                 sizeof(uevent_param->name));
1302                 uevent_param->instrumentation =
1303                         old_uevent_param->instrumentation;
1304
1305                 switch (old_uevent_param->instrumentation) {
1306                 case LTTNG_KERNEL_KPROBE:
1307                         uevent_param->u.kprobe.addr =
1308                                 old_uevent_param->u.kprobe.addr;
1309                         uevent_param->u.kprobe.offset =
1310                                 old_uevent_param->u.kprobe.offset;
1311                         memcpy(uevent_param->u.kprobe.symbol_name,
1312                                 old_uevent_param->u.kprobe.symbol_name,
1313                                 sizeof(uevent_param->u.kprobe.symbol_name));
1314                         break;
1315                 case LTTNG_KERNEL_KRETPROBE:
1316                         uevent_param->u.kretprobe.addr =
1317                                 old_uevent_param->u.kretprobe.addr;
1318                         uevent_param->u.kretprobe.offset =
1319                                 old_uevent_param->u.kretprobe.offset;
1320                         memcpy(uevent_param->u.kretprobe.symbol_name,
1321                                 old_uevent_param->u.kretprobe.symbol_name,
1322                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1323                         break;
1324                 case LTTNG_KERNEL_FUNCTION:
1325                         WARN_ON_ONCE(1);
1326                         /* Not implemented. */
1327                         break;
1328                 default:
1329                         break;
1330                 }
1331                 ret = lttng_abi_create_event(file, uevent_param);
1332
1333 old_event_error_free_old_param:
1334                 kfree(old_uevent_param);
1335 old_event_error_free_param:
1336                 kfree(uevent_param);
1337 old_event_end:
1338                 return ret;
1339         }
1340         case LTTNG_KERNEL_EVENT:
1341         {
1342                 struct lttng_kernel_event uevent_param;
1343
1344                 if (copy_from_user(&uevent_param,
1345                                 (struct lttng_kernel_event __user *) arg,
1346                                 sizeof(uevent_param)))
1347                         return -EFAULT;
1348                 return lttng_abi_create_event(file, &uevent_param);
1349         }
1350         case LTTNG_KERNEL_OLD_CONTEXT:
1351         {
1352                 struct lttng_kernel_context *ucontext_param;
1353                 struct lttng_kernel_old_context *old_ucontext_param;
1354                 int ret;
1355
1356                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1357                                 GFP_KERNEL);
1358                 if (!ucontext_param) {
1359                         ret = -ENOMEM;
1360                         goto old_ctx_end;
1361                 }
1362                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1363                                 GFP_KERNEL);
1364                 if (!old_ucontext_param) {
1365                         ret = -ENOMEM;
1366                         goto old_ctx_error_free_param;
1367                 }
1368
1369                 if (copy_from_user(old_ucontext_param,
1370                                 (struct lttng_kernel_old_context __user *) arg,
1371                                 sizeof(struct lttng_kernel_old_context))) {
1372                         ret = -EFAULT;
1373                         goto old_ctx_error_free_old_param;
1374                 }
1375                 ucontext_param->ctx = old_ucontext_param->ctx;
1376                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1377                                 sizeof(ucontext_param->padding));
1378                 /* only type that uses the union */
1379                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1380                         ucontext_param->u.perf_counter.type =
1381                                 old_ucontext_param->u.perf_counter.type;
1382                         ucontext_param->u.perf_counter.config =
1383                                 old_ucontext_param->u.perf_counter.config;
1384                         memcpy(ucontext_param->u.perf_counter.name,
1385                                 old_ucontext_param->u.perf_counter.name,
1386                                 sizeof(ucontext_param->u.perf_counter.name));
1387                 }
1388
1389                 ret = lttng_abi_add_context(file,
1390                                 ucontext_param,
1391                                 &channel->ctx, channel->session);
1392
1393 old_ctx_error_free_old_param:
1394                 kfree(old_ucontext_param);
1395 old_ctx_error_free_param:
1396                 kfree(ucontext_param);
1397 old_ctx_end:
1398                 return ret;
1399         }
1400         case LTTNG_KERNEL_CONTEXT:
1401         {
1402                 struct lttng_kernel_context ucontext_param;
1403
1404                 if (copy_from_user(&ucontext_param,
1405                                 (struct lttng_kernel_context __user *) arg,
1406                                 sizeof(ucontext_param)))
1407                         return -EFAULT;
1408                 return lttng_abi_add_context(file,
1409                                 &ucontext_param,
1410                                 &channel->ctx, channel->session);
1411         }
1412         case LTTNG_KERNEL_OLD_ENABLE:
1413         case LTTNG_KERNEL_ENABLE:
1414                 return lttng_channel_enable(channel);
1415         case LTTNG_KERNEL_OLD_DISABLE:
1416         case LTTNG_KERNEL_DISABLE:
1417                 return lttng_channel_disable(channel);
1418         case LTTNG_KERNEL_SYSCALL_MASK:
1419                 return lttng_channel_syscall_mask(channel,
1420                         (struct lttng_kernel_syscall_mask __user *) arg);
1421         default:
1422                 return -ENOIOCTLCMD;
1423         }
1424 }
1425
1426 /**
1427  *      lttng_metadata_ioctl - lttng syscall through ioctl
1428  *
1429  *      @file: the file
1430  *      @cmd: the command
1431  *      @arg: command arg
1432  *
1433  *      This ioctl implements lttng commands:
1434  *      LTTNG_KERNEL_STREAM
1435  *              Returns an event stream file descriptor or failure.
1436  *
1437  * Channel and event file descriptors also hold a reference on the session.
1438  */
1439 static
1440 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1441 {
1442         switch (cmd) {
1443         case LTTNG_KERNEL_OLD_STREAM:
1444         case LTTNG_KERNEL_STREAM:
1445                 return lttng_abi_open_metadata_stream(file);
1446         default:
1447                 return -ENOIOCTLCMD;
1448         }
1449 }
1450
1451 /**
1452  *      lttng_channel_poll - lttng stream addition/removal monitoring
1453  *
1454  *      @file: the file
1455  *      @wait: poll table
1456  */
1457 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1458 {
1459         struct lttng_channel *channel = file->private_data;
1460         unsigned int mask = 0;
1461
1462         if (file->f_mode & FMODE_READ) {
1463                 poll_wait_set_exclusive(wait);
1464                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1465                           wait);
1466
1467                 if (channel->ops->is_disabled(channel->chan))
1468                         return POLLERR;
1469                 if (channel->ops->is_finalized(channel->chan))
1470                         return POLLHUP;
1471                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1472                         return POLLIN | POLLRDNORM;
1473                 return 0;
1474         }
1475         return mask;
1476
1477 }
1478
1479 static
1480 int lttng_channel_release(struct inode *inode, struct file *file)
1481 {
1482         struct lttng_channel *channel = file->private_data;
1483
1484         if (channel)
1485                 fput(channel->session->file);
1486         return 0;
1487 }
1488
1489 static
1490 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1491 {
1492         struct lttng_channel *channel = file->private_data;
1493
1494         if (channel) {
1495                 fput(channel->session->file);
1496                 lttng_metadata_channel_destroy(channel);
1497         }
1498
1499         return 0;
1500 }
1501
1502 static const struct file_operations lttng_channel_fops = {
1503         .owner = THIS_MODULE,
1504         .release = lttng_channel_release,
1505         .poll = lttng_channel_poll,
1506         .unlocked_ioctl = lttng_channel_ioctl,
1507 #ifdef CONFIG_COMPAT
1508         .compat_ioctl = lttng_channel_ioctl,
1509 #endif
1510 };
1511
1512 static const struct file_operations lttng_metadata_fops = {
1513         .owner = THIS_MODULE,
1514         .release = lttng_metadata_channel_release,
1515         .unlocked_ioctl = lttng_metadata_ioctl,
1516 #ifdef CONFIG_COMPAT
1517         .compat_ioctl = lttng_metadata_ioctl,
1518 #endif
1519 };
1520
1521 /**
1522  *      lttng_event_ioctl - lttng syscall through ioctl
1523  *
1524  *      @file: the file
1525  *      @cmd: the command
1526  *      @arg: command arg
1527  *
1528  *      This ioctl implements lttng commands:
1529  *      LTTNG_KERNEL_CONTEXT
1530  *              Prepend a context field to each record of this event
1531  *      LTTNG_KERNEL_ENABLE
1532  *              Enable recording for this event (weak enable)
1533  *      LTTNG_KERNEL_DISABLE
1534  *              Disable recording for this event (strong disable)
1535  */
1536 static
1537 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1538 {
1539         struct lttng_event *event;
1540         struct lttng_enabler *enabler;
1541         enum lttng_event_type *evtype = file->private_data;
1542
1543         switch (cmd) {
1544         case LTTNG_KERNEL_OLD_CONTEXT:
1545         {
1546                 /* Not implemented */
1547                 return -ENOSYS;
1548         }
1549         case LTTNG_KERNEL_CONTEXT:
1550         {
1551                 /* Not implemented */
1552                 return -ENOSYS;
1553         }
1554         case LTTNG_KERNEL_OLD_ENABLE:
1555         case LTTNG_KERNEL_ENABLE:
1556                 switch (*evtype) {
1557                 case LTTNG_TYPE_EVENT:
1558                         event = file->private_data;
1559                         return lttng_event_enable(event);
1560                 case LTTNG_TYPE_ENABLER:
1561                         enabler = file->private_data;
1562                         return lttng_enabler_enable(enabler);
1563                 default:
1564                         WARN_ON_ONCE(1);
1565                         return -ENOSYS;
1566                 }
1567         case LTTNG_KERNEL_OLD_DISABLE:
1568         case LTTNG_KERNEL_DISABLE:
1569                 switch (*evtype) {
1570                 case LTTNG_TYPE_EVENT:
1571                         event = file->private_data;
1572                         return lttng_event_disable(event);
1573                 case LTTNG_TYPE_ENABLER:
1574                         enabler = file->private_data;
1575                         return lttng_enabler_disable(enabler);
1576                 default:
1577                         WARN_ON_ONCE(1);
1578                         return -ENOSYS;
1579                 }
1580         case LTTNG_KERNEL_FILTER:
1581                 switch (*evtype) {
1582                 case LTTNG_TYPE_EVENT:
1583                         return -EINVAL;
1584                 case LTTNG_TYPE_ENABLER:
1585                 {
1586                         enabler = file->private_data;
1587                         return lttng_enabler_attach_bytecode(enabler,
1588                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1589                 }
1590                 default:
1591                         WARN_ON_ONCE(1);
1592                         return -ENOSYS;
1593                 }
1594         case LTTNG_KERNEL_ADD_CALLSITE:
1595                 switch (*evtype) {
1596                 case LTTNG_TYPE_EVENT:
1597                         event = file->private_data;
1598                         return lttng_event_add_callsite(event,
1599                                 (struct lttng_kernel_event_callsite __user *) arg);
1600                 case LTTNG_TYPE_ENABLER:
1601                         return -EINVAL;
1602                 default:
1603                         WARN_ON_ONCE(1);
1604                         return -ENOSYS;
1605                 }
1606         default:
1607                 return -ENOIOCTLCMD;
1608         }
1609 }
1610
1611 static
1612 int lttng_event_release(struct inode *inode, struct file *file)
1613 {
1614         struct lttng_event *event;
1615         struct lttng_enabler *enabler;
1616         enum lttng_event_type *evtype = file->private_data;
1617
1618         if (!evtype)
1619                 return 0;
1620
1621         switch (*evtype) {
1622         case LTTNG_TYPE_EVENT:
1623                 event = file->private_data;
1624                 if (event)
1625                         fput(event->chan->file);
1626                 break;
1627         case LTTNG_TYPE_ENABLER:
1628                 enabler = file->private_data;
1629                 if (enabler)
1630                         fput(enabler->chan->file);
1631                 break;
1632         default:
1633                 WARN_ON_ONCE(1);
1634                 break;
1635         }
1636
1637         return 0;
1638 }
1639
1640 /* TODO: filter control ioctl */
1641 static const struct file_operations lttng_event_fops = {
1642         .owner = THIS_MODULE,
1643         .release = lttng_event_release,
1644         .unlocked_ioctl = lttng_event_ioctl,
1645 #ifdef CONFIG_COMPAT
1646         .compat_ioctl = lttng_event_ioctl,
1647 #endif
1648 };
1649
1650 static int put_u64(uint64_t val, unsigned long arg)
1651 {
1652         return put_user(val, (uint64_t __user *) arg);
1653 }
1654
1655 static int put_u32(uint32_t val, unsigned long arg)
1656 {
1657         return put_user(val, (uint32_t __user *) arg);
1658 }
1659
1660 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1661                 unsigned int cmd, unsigned long arg)
1662 {
1663         struct lib_ring_buffer *buf = filp->private_data;
1664         struct channel *chan = buf->backend.chan;
1665         const struct lib_ring_buffer_config *config = &chan->backend.config;
1666         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1667         int ret;
1668
1669         if (atomic_read(&chan->record_disabled))
1670                 return -EIO;
1671
1672         switch (cmd) {
1673         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1674         {
1675                 uint64_t ts;
1676
1677                 ret = ops->timestamp_begin(config, buf, &ts);
1678                 if (ret < 0)
1679                         goto error;
1680                 return put_u64(ts, arg);
1681         }
1682         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1683         {
1684                 uint64_t ts;
1685
1686                 ret = ops->timestamp_end(config, buf, &ts);
1687                 if (ret < 0)
1688                         goto error;
1689                 return put_u64(ts, arg);
1690         }
1691         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1692         {
1693                 uint64_t ed;
1694
1695                 ret = ops->events_discarded(config, buf, &ed);
1696                 if (ret < 0)
1697                         goto error;
1698                 return put_u64(ed, arg);
1699         }
1700         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1701         {
1702                 uint64_t cs;
1703
1704                 ret = ops->content_size(config, buf, &cs);
1705                 if (ret < 0)
1706                         goto error;
1707                 return put_u64(cs, arg);
1708         }
1709         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1710         {
1711                 uint64_t ps;
1712
1713                 ret = ops->packet_size(config, buf, &ps);
1714                 if (ret < 0)
1715                         goto error;
1716                 return put_u64(ps, arg);
1717         }
1718         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1719         {
1720                 uint64_t si;
1721
1722                 ret = ops->stream_id(config, buf, &si);
1723                 if (ret < 0)
1724                         goto error;
1725                 return put_u64(si, arg);
1726         }
1727         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1728         {
1729                 uint64_t ts;
1730
1731                 ret = ops->current_timestamp(config, buf, &ts);
1732                 if (ret < 0)
1733                         goto error;
1734                 return put_u64(ts, arg);
1735         }
1736         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1737         {
1738                 uint64_t seq;
1739
1740                 ret = ops->sequence_number(config, buf, &seq);
1741                 if (ret < 0)
1742                         goto error;
1743                 return put_u64(seq, arg);
1744         }
1745         case LTTNG_RING_BUFFER_INSTANCE_ID:
1746         {
1747                 uint64_t id;
1748
1749                 ret = ops->instance_id(config, buf, &id);
1750                 if (ret < 0)
1751                         goto error;
1752                 return put_u64(id, arg);
1753         }
1754         default:
1755                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1756                                 cmd, arg);
1757         }
1758
1759 error:
1760         return -ENOSYS;
1761 }
1762
1763 #ifdef CONFIG_COMPAT
1764 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1765                 unsigned int cmd, unsigned long arg)
1766 {
1767         struct lib_ring_buffer *buf = filp->private_data;
1768         struct channel *chan = buf->backend.chan;
1769         const struct lib_ring_buffer_config *config = &chan->backend.config;
1770         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1771         int ret;
1772
1773         if (atomic_read(&chan->record_disabled))
1774                 return -EIO;
1775
1776         switch (cmd) {
1777         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1778         {
1779                 uint64_t ts;
1780
1781                 ret = ops->timestamp_begin(config, buf, &ts);
1782                 if (ret < 0)
1783                         goto error;
1784                 return put_u64(ts, arg);
1785         }
1786         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1787         {
1788                 uint64_t ts;
1789
1790                 ret = ops->timestamp_end(config, buf, &ts);
1791                 if (ret < 0)
1792                         goto error;
1793                 return put_u64(ts, arg);
1794         }
1795         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1796         {
1797                 uint64_t ed;
1798
1799                 ret = ops->events_discarded(config, buf, &ed);
1800                 if (ret < 0)
1801                         goto error;
1802                 return put_u64(ed, arg);
1803         }
1804         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1805         {
1806                 uint64_t cs;
1807
1808                 ret = ops->content_size(config, buf, &cs);
1809                 if (ret < 0)
1810                         goto error;
1811                 return put_u64(cs, arg);
1812         }
1813         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1814         {
1815                 uint64_t ps;
1816
1817                 ret = ops->packet_size(config, buf, &ps);
1818                 if (ret < 0)
1819                         goto error;
1820                 return put_u64(ps, arg);
1821         }
1822         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1823         {
1824                 uint64_t si;
1825
1826                 ret = ops->stream_id(config, buf, &si);
1827                 if (ret < 0)
1828                         goto error;
1829                 return put_u64(si, arg);
1830         }
1831         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1832         {
1833                 uint64_t ts;
1834
1835                 ret = ops->current_timestamp(config, buf, &ts);
1836                 if (ret < 0)
1837                         goto error;
1838                 return put_u64(ts, arg);
1839         }
1840         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1841         {
1842                 uint64_t seq;
1843
1844                 ret = ops->sequence_number(config, buf, &seq);
1845                 if (ret < 0)
1846                         goto error;
1847                 return put_u64(seq, arg);
1848         }
1849         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1850         {
1851                 uint64_t id;
1852
1853                 ret = ops->instance_id(config, buf, &id);
1854                 if (ret < 0)
1855                         goto error;
1856                 return put_u64(id, arg);
1857         }
1858         default:
1859                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1860                                 cmd, arg);
1861         }
1862
1863 error:
1864         return -ENOSYS;
1865 }
1866 #endif /* CONFIG_COMPAT */
1867
1868 static void lttng_stream_override_ring_buffer_fops(void)
1869 {
1870         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1871         lttng_stream_ring_buffer_file_operations.open =
1872                 lib_ring_buffer_file_operations.open;
1873         lttng_stream_ring_buffer_file_operations.release =
1874                 lib_ring_buffer_file_operations.release;
1875         lttng_stream_ring_buffer_file_operations.poll =
1876                 lib_ring_buffer_file_operations.poll;
1877         lttng_stream_ring_buffer_file_operations.splice_read =
1878                 lib_ring_buffer_file_operations.splice_read;
1879         lttng_stream_ring_buffer_file_operations.mmap =
1880                 lib_ring_buffer_file_operations.mmap;
1881         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1882                 lttng_stream_ring_buffer_ioctl;
1883         lttng_stream_ring_buffer_file_operations.llseek =
1884                 lib_ring_buffer_file_operations.llseek;
1885 #ifdef CONFIG_COMPAT
1886         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1887                 lttng_stream_ring_buffer_compat_ioctl;
1888 #endif
1889 }
1890
1891 int __init lttng_abi_init(void)
1892 {
1893         int ret = 0;
1894
1895         wrapper_vmalloc_sync_mappings();
1896         lttng_clock_ref();
1897
1898         ret = lttng_tp_mempool_init();
1899         if (ret) {
1900                 goto error;
1901         }
1902
1903         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1904                                         &lttng_proc_ops, NULL);
1905
1906         if (!lttng_proc_dentry) {
1907                 printk(KERN_ERR "Error creating LTTng control file\n");
1908                 ret = -ENOMEM;
1909                 goto error;
1910         }
1911         lttng_stream_override_ring_buffer_fops();
1912         return 0;
1913
1914 error:
1915         lttng_tp_mempool_destroy();
1916         lttng_clock_unref();
1917         return ret;
1918 }
1919
1920 /* No __exit annotation because used by init error path too. */
1921 void lttng_abi_exit(void)
1922 {
1923         lttng_tp_mempool_destroy();
1924         lttng_clock_unref();
1925         if (lttng_proc_dentry)
1926                 remove_proc_entry("lttng", NULL);
1927 }