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_all() */
  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 static const struct file_operations lttng_fops;
  55 static const struct file_operations lttng_session_fops;
  56 static const struct file_operations lttng_channel_fops;
  57 static const struct file_operations lttng_metadata_fops;
  58 static const struct file_operations lttng_event_fops;
  59 static struct file_operations lttng_stream_ring_buffer_file_operations;
  60
  61 static int put_u64(uint64_t val, unsigned long arg);
  62
  63 /*
  64  * Teardown management: opened file descriptors keep a refcount on the module,
  65  * so it can only exit when all file descriptors are closed.
  66  */
  67
  68 static
  69 int lttng_abi_create_session(void)
  70 {
  71         struct lttng_session *session;
  72         struct file *session_file;
  73         int session_fd, ret;
  74
  75         session = lttng_session_create();
  76         if (!session)
  77                 return -ENOMEM;
  78         session_fd = lttng_get_unused_fd();
  79         if (session_fd < 0) {
  80                 ret = session_fd;
  81                 goto fd_error;
  82         }
  83         session_file = anon_inode_getfile("[lttng_session]",
  84                                           &lttng_session_fops,
  85                                           session, O_RDWR);
  86         if (IS_ERR(session_file)) {
  87                 ret = PTR_ERR(session_file);
  88                 goto file_error;
  89         }
  90         session->file = session_file;
  91         fd_install(session_fd, session_file);
  92         return session_fd;
  93
  94 file_error:
  95         put_unused_fd(session_fd);
  96 fd_error:
  97         lttng_session_destroy(session);
  98         return ret;
  99 }
 100
 101 static
 102 int lttng_abi_tracepoint_list(void)
 103 {
 104         struct file *tracepoint_list_file;
 105         int file_fd, ret;
 106
 107         file_fd = lttng_get_unused_fd();
 108         if (file_fd < 0) {
 109                 ret = file_fd;
 110                 goto fd_error;
 111         }
 112
 113         tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
 114                                           &lttng_tracepoint_list_fops,
 115                                           NULL, O_RDWR);
 116         if (IS_ERR(tracepoint_list_file)) {
 117                 ret = PTR_ERR(tracepoint_list_file);
 118                 goto file_error;
 119         }
 120         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 121         if (ret < 0)
 122                 goto open_error;
 123         fd_install(file_fd, tracepoint_list_file);
 124         return file_fd;
 125
 126 open_error:
 127         fput(tracepoint_list_file);
 128 file_error:
 129         put_unused_fd(file_fd);
 130 fd_error:
 131         return ret;
 132 }
 133
 134 #ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 135 static inline
 136 int lttng_abi_syscall_list(void)
 137 {
 138         return -ENOSYS;
 139 }
 140 #else
 141 static
 142 int lttng_abi_syscall_list(void)
 143 {
 144         struct file *syscall_list_file;
 145         int file_fd, ret;
 146
 147         file_fd = lttng_get_unused_fd();
 148         if (file_fd < 0) {
 149                 ret = file_fd;
 150                 goto fd_error;
 151         }
 152
 153         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
 154                                           &lttng_syscall_list_fops,
 155                                           NULL, O_RDWR);
 156         if (IS_ERR(syscall_list_file)) {
 157                 ret = PTR_ERR(syscall_list_file);
 158                 goto file_error;
 159         }
 160         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
 161         if (ret < 0)
 162                 goto open_error;
 163         fd_install(file_fd, syscall_list_file);
 164         return file_fd;
 165
 166 open_error:
 167         fput(syscall_list_file);
 168 file_error:
 169         put_unused_fd(file_fd);
 170 fd_error:
 171         return ret;
 172 }
 173 #endif
 174
 175 static
 176 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 177 {
 178         v->major = LTTNG_MODULES_MAJOR_VERSION;
 179         v->minor = LTTNG_MODULES_MINOR_VERSION;
 180         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 181 }
 182
 183 static
 184 void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
 185 {
 186         v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
 187         v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
 188 }
 189
 190 static
 191 long lttng_abi_add_context(struct file *file,
 192         struct lttng_kernel_context *context_param,
 193         struct lttng_ctx **ctx, struct lttng_session *session)
 194 {
 195
 196         if (session->been_active)
 197                 return -EPERM;
 198
 199         switch (context_param->ctx) {
 200         case LTTNG_KERNEL_CONTEXT_PID:
 201                 return lttng_add_pid_to_ctx(ctx);
 202         case LTTNG_KERNEL_CONTEXT_PRIO:
 203                 return lttng_add_prio_to_ctx(ctx);
 204         case LTTNG_KERNEL_CONTEXT_NICE:
 205                 return lttng_add_nice_to_ctx(ctx);
 206         case LTTNG_KERNEL_CONTEXT_VPID:
 207                 return lttng_add_vpid_to_ctx(ctx);
 208         case LTTNG_KERNEL_CONTEXT_TID:
 209                 return lttng_add_tid_to_ctx(ctx);
 210         case LTTNG_KERNEL_CONTEXT_VTID:
 211                 return lttng_add_vtid_to_ctx(ctx);
 212         case LTTNG_KERNEL_CONTEXT_PPID:
 213                 return lttng_add_ppid_to_ctx(ctx);
 214         case LTTNG_KERNEL_CONTEXT_VPPID:
 215                 return lttng_add_vppid_to_ctx(ctx);
 216         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 217                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 218                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 219                                 context_param->u.perf_counter.config,
 220                                 context_param->u.perf_counter.name,
 221                                 ctx);
 222         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 223                 return lttng_add_procname_to_ctx(ctx);
 224         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 225                 return lttng_add_hostname_to_ctx(ctx);
 226         case LTTNG_KERNEL_CONTEXT_CPU_ID:
 227                 return lttng_add_cpu_id_to_ctx(ctx);
 228         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 229                 return lttng_add_interruptible_to_ctx(ctx);
 230         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 231                 return lttng_add_need_reschedule_to_ctx(ctx);
 232         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 233                 return lttng_add_preemptible_to_ctx(ctx);
 234         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 235                 return lttng_add_migratable_to_ctx(ctx);
 236         case LTTNG_KERNEL_CONTEXT_CALLSTACK_KERNEL:
 237         case LTTNG_KERNEL_CONTEXT_CALLSTACK_USER:
 238                 return lttng_add_callstack_to_ctx(ctx, context_param->ctx);
 239         default:
 240                 return -EINVAL;
 241         }
 242 }
 243
 244 /**
 245  *      lttng_ioctl - lttng syscall through ioctl
 246  *
 247  *      @file: the file
 248  *      @cmd: the command
 249  *      @arg: command arg
 250  *
 251  *      This ioctl implements lttng commands:
 252  *      LTTNG_KERNEL_SESSION
 253  *              Returns a LTTng trace session file descriptor
 254  *      LTTNG_KERNEL_TRACER_VERSION
 255  *              Returns the LTTng kernel tracer version
 256  *      LTTNG_KERNEL_TRACEPOINT_LIST
 257  *              Returns a file descriptor listing available tracepoints
 258  *      LTTNG_KERNEL_WAIT_QUIESCENT
 259  *              Returns after all previously running probes have completed
 260  *      LTTNG_KERNEL_TRACER_ABI_VERSION
 261  *              Returns the LTTng kernel tracer ABI version
 262  *
 263  * The returned session will be deleted when its file descriptor is closed.
 264  */
 265 static
 266 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 267 {
 268         switch (cmd) {
 269         case LTTNG_KERNEL_OLD_SESSION:
 270         case LTTNG_KERNEL_SESSION:
 271                 return lttng_abi_create_session();
 272         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 273         {
 274                 struct lttng_kernel_tracer_version v;
 275                 struct lttng_kernel_old_tracer_version oldv;
 276                 struct lttng_kernel_old_tracer_version *uversion =
 277                         (struct lttng_kernel_old_tracer_version __user *) arg;
 278
 279                 lttng_abi_tracer_version(&v);
 280                 oldv.major = v.major;
 281                 oldv.minor = v.minor;
 282                 oldv.patchlevel = v.patchlevel;
 283
 284                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 285                         return -EFAULT;
 286                 return 0;
 287         }
 288         case LTTNG_KERNEL_TRACER_VERSION:
 289         {
 290                 struct lttng_kernel_tracer_version version;
 291                 struct lttng_kernel_tracer_version *uversion =
 292                         (struct lttng_kernel_tracer_version __user *) arg;
 293
 294                 lttng_abi_tracer_version(&version);
 295
 296                 if (copy_to_user(uversion, &version, sizeof(version)))
 297                         return -EFAULT;
 298                 return 0;
 299         }
 300         case LTTNG_KERNEL_TRACER_ABI_VERSION:
 301         {
 302                 struct lttng_kernel_tracer_abi_version version;
 303                 struct lttng_kernel_tracer_abi_version *uversion =
 304                         (struct lttng_kernel_tracer_abi_version __user *) arg;
 305
 306                 lttng_abi_tracer_abi_version(&version);
 307
 308                 if (copy_to_user(uversion, &version, sizeof(version)))
 309                         return -EFAULT;
 310                 return 0;
 311         }
 312         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 313         case LTTNG_KERNEL_TRACEPOINT_LIST:
 314                 return lttng_abi_tracepoint_list();
 315         case LTTNG_KERNEL_SYSCALL_LIST:
 316                 return lttng_abi_syscall_list();
 317         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 318         case LTTNG_KERNEL_WAIT_QUIESCENT:
 319                 synchronize_trace();
 320                 return 0;
 321         case LTTNG_KERNEL_OLD_CALIBRATE:
 322         {
 323                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 324                         (struct lttng_kernel_old_calibrate __user *) arg;
 325                 struct lttng_kernel_old_calibrate old_calibrate;
 326                 struct lttng_kernel_calibrate calibrate;
 327                 int ret;
 328
 329                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 330                         return -EFAULT;
 331                 calibrate.type = old_calibrate.type;
 332                 ret = lttng_calibrate(&calibrate);
 333                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 334                         return -EFAULT;
 335                 return ret;
 336         }
 337         case LTTNG_KERNEL_CALIBRATE:
 338         {
 339                 struct lttng_kernel_calibrate __user *ucalibrate =
 340                         (struct lttng_kernel_calibrate __user *) arg;
 341                 struct lttng_kernel_calibrate calibrate;
 342                 int ret;
 343
 344                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 345                         return -EFAULT;
 346                 ret = lttng_calibrate(&calibrate);
 347                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 348                         return -EFAULT;
 349                 return ret;
 350         }
 351         default:
 352                 return -ENOIOCTLCMD;
 353         }
 354 }
 355
 356 static const struct file_operations lttng_fops = {
 357         .owner = THIS_MODULE,
 358         .unlocked_ioctl = lttng_ioctl,
 359 #ifdef CONFIG_COMPAT
 360         .compat_ioctl = lttng_ioctl,
 361 #endif
 362 };
 363
 364 static
 365 int lttng_abi_create_channel(struct file *session_file,
 366                              struct lttng_kernel_channel *chan_param,
 367                              enum channel_type channel_type)
 368 {
 369         struct lttng_session *session = session_file->private_data;
 370         const struct file_operations *fops = NULL;
 371         const char *transport_name;
 372         struct lttng_channel *chan;
 373         struct file *chan_file;
 374         int chan_fd;
 375         int ret = 0;
 376
 377         chan_fd = lttng_get_unused_fd();
 378         if (chan_fd < 0) {
 379                 ret = chan_fd;
 380                 goto fd_error;
 381         }
 382         switch (channel_type) {
 383         case PER_CPU_CHANNEL:
 384                 fops = &lttng_channel_fops;
 385                 break;
 386         case METADATA_CHANNEL:
 387                 fops = &lttng_metadata_fops;
 388                 break;
 389         }
 390
 391         chan_file = anon_inode_getfile("[lttng_channel]",
 392                                        fops,
 393                                        NULL, O_RDWR);
 394         if (IS_ERR(chan_file)) {
 395                 ret = PTR_ERR(chan_file);
 396                 goto file_error;
 397         }
 398         switch (channel_type) {
 399         case PER_CPU_CHANNEL:
 400                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 401                         transport_name = chan_param->overwrite ?
 402                                 "relay-overwrite" : "relay-discard";
 403                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 404                         transport_name = chan_param->overwrite ?
 405                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 406                 } else {
 407                         return -EINVAL;
 408                 }
 409                 break;
 410         case METADATA_CHANNEL:
 411                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 412                         transport_name = "relay-metadata";
 413                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 414                         transport_name = "relay-metadata-mmap";
 415                 else
 416                         return -EINVAL;
 417                 break;
 418         default:
 419                 transport_name = "<unknown>";
 420                 break;
 421         }
 422         if (!atomic_long_add_unless(&session_file->f_count, 1, LONG_MAX)) {
 423                 ret = -EOVERFLOW;
 424                 goto refcount_error;
 425         }
 426         /*
 427          * We tolerate no failure path after channel creation. It will stay
 428          * invariant for the rest of the session.
 429          */
 430         chan = lttng_channel_create(session, transport_name, NULL,
 431                                   chan_param->subbuf_size,
 432                                   chan_param->num_subbuf,
 433                                   chan_param->switch_timer_interval,
 434                                   chan_param->read_timer_interval,
 435                                   channel_type);
 436         if (!chan) {
 437                 ret = -EINVAL;
 438                 goto chan_error;
 439         }
 440         chan->file = chan_file;
 441         chan_file->private_data = chan;
 442         fd_install(chan_fd, chan_file);
 443
 444         return chan_fd;
 445
 446 chan_error:
 447         atomic_long_dec(&session_file->f_count);
 448 refcount_error:
 449         fput(chan_file);
 450 file_error:
 451         put_unused_fd(chan_fd);
 452 fd_error:
 453         return ret;
 454 }
 455
 456 static
 457 int lttng_abi_session_set_name(struct lttng_session *session,
 458                 struct lttng_kernel_session_name *name)
 459 {
 460         size_t len;
 461
 462         len = strnlen(name->name, LTTNG_KERNEL_SESSION_NAME_LEN);
 463
 464         if (len == LTTNG_KERNEL_SESSION_NAME_LEN) {
 465                 /* Name is too long/malformed */
 466                 return -EINVAL;
 467         }
 468
 469         strcpy(session->name, name->name);
 470         return 0;
 471 }
 472
 473 /**
 474  *      lttng_session_ioctl - lttng session fd ioctl
 475  *
 476  *      @file: the file
 477  *      @cmd: the command
 478  *      @arg: command arg
 479  *
 480  *      This ioctl implements lttng commands:
 481  *      LTTNG_KERNEL_CHANNEL
 482  *              Returns a LTTng channel file descriptor
 483  *      LTTNG_KERNEL_ENABLE
 484  *              Enables tracing for a session (weak enable)
 485  *      LTTNG_KERNEL_DISABLE
 486  *              Disables tracing for a session (strong disable)
 487  *      LTTNG_KERNEL_METADATA
 488  *              Returns a LTTng metadata file descriptor
 489  *      LTTNG_KERNEL_SESSION_TRACK_PID
 490  *              Add PID to session tracker
 491  *      LTTNG_KERNEL_SESSION_UNTRACK_PID
 492  *              Remove PID from session tracker
 493  *
 494  * The returned channel will be deleted when its file descriptor is closed.
 495  */
 496 static
 497 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 498 {
 499         struct lttng_session *session = file->private_data;
 500
 501         switch (cmd) {
 502         case LTTNG_KERNEL_OLD_CHANNEL:
 503         {
 504                 struct lttng_kernel_channel chan_param;
 505                 struct lttng_kernel_old_channel old_chan_param;
 506
 507                 if (copy_from_user(&old_chan_param,
 508                                 (struct lttng_kernel_old_channel __user *) arg,
 509                                 sizeof(struct lttng_kernel_old_channel)))
 510                         return -EFAULT;
 511                 chan_param.overwrite = old_chan_param.overwrite;
 512                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 513                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 514                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 515                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 516                 chan_param.output = old_chan_param.output;
 517
 518                 return lttng_abi_create_channel(file, &chan_param,
 519                                 PER_CPU_CHANNEL);
 520         }
 521         case LTTNG_KERNEL_CHANNEL:
 522         {
 523                 struct lttng_kernel_channel chan_param;
 524
 525                 if (copy_from_user(&chan_param,
 526                                 (struct lttng_kernel_channel __user *) arg,
 527                                 sizeof(struct lttng_kernel_channel)))
 528                         return -EFAULT;
 529                 return lttng_abi_create_channel(file, &chan_param,
 530                                 PER_CPU_CHANNEL);
 531         }
 532         case LTTNG_KERNEL_OLD_SESSION_START:
 533         case LTTNG_KERNEL_OLD_ENABLE:
 534         case LTTNG_KERNEL_SESSION_START:
 535         case LTTNG_KERNEL_ENABLE:
 536                 return lttng_session_enable(session);
 537         case LTTNG_KERNEL_OLD_SESSION_STOP:
 538         case LTTNG_KERNEL_OLD_DISABLE:
 539         case LTTNG_KERNEL_SESSION_STOP:
 540         case LTTNG_KERNEL_DISABLE:
 541                 return lttng_session_disable(session);
 542         case LTTNG_KERNEL_OLD_METADATA:
 543         {
 544                 struct lttng_kernel_channel chan_param;
 545                 struct lttng_kernel_old_channel old_chan_param;
 546
 547                 if (copy_from_user(&old_chan_param,
 548                                 (struct lttng_kernel_old_channel __user *) arg,
 549                                 sizeof(struct lttng_kernel_old_channel)))
 550                         return -EFAULT;
 551                 chan_param.overwrite = old_chan_param.overwrite;
 552                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 553                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 554                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 555                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 556                 chan_param.output = old_chan_param.output;
 557
 558                 return lttng_abi_create_channel(file, &chan_param,
 559                                 METADATA_CHANNEL);
 560         }
 561         case LTTNG_KERNEL_METADATA:
 562         {
 563                 struct lttng_kernel_channel chan_param;
 564
 565                 if (copy_from_user(&chan_param,
 566                                         (struct lttng_kernel_channel __user *) arg,
 567                                         sizeof(struct lttng_kernel_channel)))
 568                         return -EFAULT;
 569                 return lttng_abi_create_channel(file, &chan_param,
 570                                 METADATA_CHANNEL);
 571         }
 572         case LTTNG_KERNEL_SESSION_TRACK_PID:
 573                 return lttng_session_track_pid(session, (int) arg);
 574         case LTTNG_KERNEL_SESSION_UNTRACK_PID:
 575                 return lttng_session_untrack_pid(session, (int) arg);
 576         case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
 577                 return lttng_session_list_tracker_pids(session);
 578         case LTTNG_KERNEL_SESSION_METADATA_REGEN:
 579                 return lttng_session_metadata_regenerate(session);
 580         case LTTNG_KERNEL_SESSION_STATEDUMP:
 581                 return lttng_session_statedump(session);
 582         case LTTNG_KERNEL_SESSION_SET_NAME:
 583         {
 584                 struct lttng_kernel_session_name name;
 585
 586                 if (copy_from_user(&name,
 587                                 (struct lttng_kernel_session_name __user *) arg,
 588                                 sizeof(struct lttng_kernel_session_name)))
 589                         return -EFAULT;
 590                 return lttng_abi_session_set_name(session, &name);
 591         }
 592         default:
 593                 return -ENOIOCTLCMD;
 594         }
 595 }
 596
 597 /*
 598  * Called when the last file reference is dropped.
 599  *
 600  * Big fat note: channels and events are invariant for the whole session after
 601  * their creation. So this session destruction also destroys all channel and
 602  * event structures specific to this session (they are not destroyed when their
 603  * individual file is released).
 604  */
 605 static
 606 int lttng_session_release(struct inode *inode, struct file *file)
 607 {
 608         struct lttng_session *session = file->private_data;
 609
 610         if (session)
 611                 lttng_session_destroy(session);
 612         return 0;
 613 }
 614
 615 static const struct file_operations lttng_session_fops = {
 616         .owner = THIS_MODULE,
 617         .release = lttng_session_release,
 618         .unlocked_ioctl = lttng_session_ioctl,
 619 #ifdef CONFIG_COMPAT
 620         .compat_ioctl = lttng_session_ioctl,
 621 #endif
 622 };
 623
 624 /**
 625  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 626  *      @filp: the file
 627  *      @wait: poll table
 628  *
 629  *      Handles the poll operations for the metadata channels.
 630  */
 631 static
 632 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 633                 poll_table *wait)
 634 {
 635         struct lttng_metadata_stream *stream = filp->private_data;
 636         struct lib_ring_buffer *buf = stream->priv;
 637         int finalized;
 638         unsigned int mask = 0;
 639
 640         if (filp->f_mode & FMODE_READ) {
 641                 poll_wait_set_exclusive(wait);
 642                 poll_wait(filp, &stream->read_wait, wait);
 643
 644                 finalized = stream->finalized;
 645
 646                 /*
 647                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 648                  * ordering finalized load before offsets loads.
 649                  */
 650                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 651
 652                 if (finalized)
 653                         mask |= POLLHUP;
 654
 655                 mutex_lock(&stream->metadata_cache->lock);
 656                 if (stream->metadata_cache->metadata_written >
 657                                 stream->metadata_out)
 658                         mask |= POLLIN;
 659                 mutex_unlock(&stream->metadata_cache->lock);
 660         }
 661
 662         return mask;
 663 }
 664
 665 static
 666 void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
 667                 unsigned int cmd, unsigned long arg)
 668 {
 669         struct lttng_metadata_stream *stream = filp->private_data;
 670
 671         stream->metadata_out = stream->metadata_in;
 672 }
 673
 674 /*
 675  * Reset the counter of how much metadata has been consumed to 0. That way,
 676  * the consumer receives the content of the metadata cache unchanged. This is
 677  * different from the metadata_regenerate where the offset from epoch is
 678  * resampled, here we want the exact same content as the last time the metadata
 679  * was generated. This command is only possible if all the metadata written
 680  * in the cache has been output to the metadata stream to avoid corrupting the
 681  * metadata file.
 682  *
 683  * Return 0 on success, a negative value on error.
 684  */
 685 static
 686 int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
 687 {
 688         int ret;
 689         struct lttng_metadata_cache *cache = stream->metadata_cache;
 690
 691         mutex_lock(&cache->lock);
 692         if (stream->metadata_out != cache->metadata_written) {
 693                 ret = -EBUSY;
 694                 goto end;
 695         }
 696         stream->metadata_out = 0;
 697         stream->metadata_in = 0;
 698         wake_up_interruptible(&stream->read_wait);
 699         ret = 0;
 700
 701 end:
 702         mutex_unlock(&cache->lock);
 703         return ret;
 704 }
 705
 706 static
 707 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 708                 unsigned int cmd, unsigned long arg)
 709 {
 710         int ret;
 711         struct lttng_metadata_stream *stream = filp->private_data;
 712         struct lib_ring_buffer *buf = stream->priv;
 713
 714         switch (cmd) {
 715         case RING_BUFFER_GET_NEXT_SUBBUF:
 716         {
 717                 struct lttng_metadata_stream *stream = filp->private_data;
 718                 struct lib_ring_buffer *buf = stream->priv;
 719                 struct channel *chan = buf->backend.chan;
 720
 721                 ret = lttng_metadata_output_channel(stream, chan);
 722                 if (ret > 0) {
 723                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 724                         ret = 0;
 725                 } else if (ret < 0)
 726                         goto err;
 727                 break;
 728         }
 729         case RING_BUFFER_GET_SUBBUF:
 730         {
 731                 /*
 732                  * Random access is not allowed for metadata channel.
 733                  */
 734                 return -ENOSYS;
 735         }
 736         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 737         case RING_BUFFER_FLUSH:
 738         {
 739                 struct lttng_metadata_stream *stream = filp->private_data;
 740                 struct lib_ring_buffer *buf = stream->priv;
 741                 struct channel *chan = buf->backend.chan;
 742
 743                 /*
 744                  * Before doing the actual ring buffer flush, write up to one
 745                  * packet of metadata in the ring buffer.
 746                  */
 747                 ret = lttng_metadata_output_channel(stream, chan);
 748                 if (ret < 0)
 749                         goto err;
 750                 break;
 751         }
 752         case RING_BUFFER_GET_METADATA_VERSION:
 753         {
 754                 struct lttng_metadata_stream *stream = filp->private_data;
 755
 756                 return put_u64(stream->version, arg);
 757         }
 758         case RING_BUFFER_METADATA_CACHE_DUMP:
 759         {
 760                 struct lttng_metadata_stream *stream = filp->private_data;
 761
 762                 return lttng_metadata_cache_dump(stream);
 763         }
 764         default:
 765                 break;
 766         }
 767         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 768
 769         /* Performing lib ring buffer ioctl after our own. */
 770         ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 771         if (ret < 0)
 772                 goto err;
 773
 774         switch (cmd) {
 775         case RING_BUFFER_PUT_NEXT_SUBBUF:
 776         {
 777                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 778                                 cmd, arg);
 779                 break;
 780         }
 781         default:
 782                 break;
 783         }
 784 err:
 785         return ret;
 786 }
 787
 788 #ifdef CONFIG_COMPAT
 789 static
 790 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 791                 unsigned int cmd, unsigned long arg)
 792 {
 793         int ret;
 794         struct lttng_metadata_stream *stream = filp->private_data;
 795         struct lib_ring_buffer *buf = stream->priv;
 796
 797         switch (cmd) {
 798         case RING_BUFFER_GET_NEXT_SUBBUF:
 799         {
 800                 struct lttng_metadata_stream *stream = filp->private_data;
 801                 struct lib_ring_buffer *buf = stream->priv;
 802                 struct channel *chan = buf->backend.chan;
 803
 804                 ret = lttng_metadata_output_channel(stream, chan);
 805                 if (ret > 0) {
 806                         lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 807                         ret = 0;
 808                 } else if (ret < 0)
 809                         goto err;
 810                 break;
 811         }
 812         case RING_BUFFER_GET_SUBBUF:
 813         {
 814                 /*
 815                  * Random access is not allowed for metadata channel.
 816                  */
 817                 return -ENOSYS;
 818         }
 819         case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
 820         case RING_BUFFER_FLUSH:
 821         {
 822                 struct lttng_metadata_stream *stream = filp->private_data;
 823                 struct lib_ring_buffer *buf = stream->priv;
 824                 struct channel *chan = buf->backend.chan;
 825
 826                 /*
 827                  * Before doing the actual ring buffer flush, write up to one
 828                  * packet of metadata in the ring buffer.
 829                  */
 830                 ret = lttng_metadata_output_channel(stream, chan);
 831                 if (ret < 0)
 832                         goto err;
 833                 break;
 834         }
 835         case RING_BUFFER_GET_METADATA_VERSION:
 836         {
 837                 struct lttng_metadata_stream *stream = filp->private_data;
 838
 839                 return put_u64(stream->version, arg);
 840         }
 841         case RING_BUFFER_METADATA_CACHE_DUMP:
 842         {
 843                 struct lttng_metadata_stream *stream = filp->private_data;
 844
 845                 return lttng_metadata_cache_dump(stream);
 846         }
 847         default:
 848                 break;
 849         }
 850         /* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
 851
 852         /* Performing lib ring buffer ioctl after our own. */
 853         ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 854         if (ret < 0)
 855                 goto err;
 856
 857         switch (cmd) {
 858         case RING_BUFFER_PUT_NEXT_SUBBUF:
 859         {
 860                 lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
 861                                 cmd, arg);
 862                 break;
 863         }
 864         default:
 865                 break;
 866         }
 867 err:
 868         return ret;
 869 }
 870 #endif
 871
 872 /*
 873  * This is not used by anonymous file descriptors. This code is left
 874  * there if we ever want to implement an inode with open() operation.
 875  */
 876 static
 877 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 878 {
 879         struct lttng_metadata_stream *stream = inode->i_private;
 880         struct lib_ring_buffer *buf = stream->priv;
 881
 882         file->private_data = buf;
 883         /*
 884          * Since life-time of metadata cache differs from that of
 885          * session, we need to keep our own reference on the transport.
 886          */
 887         if (!try_module_get(stream->transport->owner)) {
 888                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 889                 return -EBUSY;
 890         }
 891         return lib_ring_buffer_open(inode, file, buf);
 892 }
 893
 894 static
 895 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 896 {
 897         struct lttng_metadata_stream *stream = file->private_data;
 898         struct lib_ring_buffer *buf = stream->priv;
 899
 900         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 901         module_put(stream->transport->owner);
 902         return lib_ring_buffer_release(inode, file, buf);
 903 }
 904
 905 static
 906 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 907                 struct pipe_inode_info *pipe, size_t len,
 908                 unsigned int flags)
 909 {
 910         struct lttng_metadata_stream *stream = in->private_data;
 911         struct lib_ring_buffer *buf = stream->priv;
 912
 913         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 914                         flags, buf);
 915 }
 916
 917 static
 918 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 919                 struct vm_area_struct *vma)
 920 {
 921         struct lttng_metadata_stream *stream = filp->private_data;
 922         struct lib_ring_buffer *buf = stream->priv;
 923
 924         return lib_ring_buffer_mmap(filp, vma, buf);
 925 }
 926
 927 static
 928 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 929         .owner = THIS_MODULE,
 930         .open = lttng_metadata_ring_buffer_open,
 931         .release = lttng_metadata_ring_buffer_release,
 932         .poll = lttng_metadata_ring_buffer_poll,
 933         .splice_read = lttng_metadata_ring_buffer_splice_read,
 934         .mmap = lttng_metadata_ring_buffer_mmap,
 935         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 936         .llseek = vfs_lib_ring_buffer_no_llseek,
 937 #ifdef CONFIG_COMPAT
 938         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 939 #endif
 940 };
 941
 942 static
 943 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 944                 const struct file_operations *fops)
 945 {
 946         int stream_fd, ret;
 947         struct file *stream_file;
 948
 949         stream_fd = lttng_get_unused_fd();
 950         if (stream_fd < 0) {
 951                 ret = stream_fd;
 952                 goto fd_error;
 953         }
 954         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 955                         stream_priv, O_RDWR);
 956         if (IS_ERR(stream_file)) {
 957                 ret = PTR_ERR(stream_file);
 958                 goto file_error;
 959         }
 960         /*
 961          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 962          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 963          * file descriptor, so we set FMODE_PREAD here.
 964          */
 965         stream_file->f_mode |= FMODE_PREAD;
 966         fd_install(stream_fd, stream_file);
 967         /*
 968          * The stream holds a reference to the channel within the generic ring
 969          * buffer library, so no need to hold a refcount on the channel and
 970          * session files here.
 971          */
 972         return stream_fd;
 973
 974 file_error:
 975         put_unused_fd(stream_fd);
 976 fd_error:
 977         return ret;
 978 }
 979
 980 static
 981 int lttng_abi_open_stream(struct file *channel_file)
 982 {
 983         struct lttng_channel *channel = channel_file->private_data;
 984         struct lib_ring_buffer *buf;
 985         int ret;
 986         void *stream_priv;
 987
 988         buf = channel->ops->buffer_read_open(channel->chan);
 989         if (!buf)
 990                 return -ENOENT;
 991
 992         stream_priv = buf;
 993         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 994                         &lttng_stream_ring_buffer_file_operations);
 995         if (ret < 0)
 996                 goto fd_error;
 997
 998         return ret;
 999
1000 fd_error:
1001         channel->ops->buffer_read_close(buf);
1002         return ret;
1003 }
1004
1005 static
1006 int lttng_abi_open_metadata_stream(struct file *channel_file)
1007 {
1008         struct lttng_channel *channel = channel_file->private_data;
1009         struct lttng_session *session = channel->session;
1010         struct lib_ring_buffer *buf;
1011         int ret;
1012         struct lttng_metadata_stream *metadata_stream;
1013         void *stream_priv;
1014
1015         buf = channel->ops->buffer_read_open(channel->chan);
1016         if (!buf)
1017                 return -ENOENT;
1018
1019         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
1020                         GFP_KERNEL);
1021         if (!metadata_stream) {
1022                 ret = -ENOMEM;
1023                 goto nomem;
1024         }
1025         metadata_stream->metadata_cache = session->metadata_cache;
1026         init_waitqueue_head(&metadata_stream->read_wait);
1027         metadata_stream->priv = buf;
1028         stream_priv = metadata_stream;
1029         metadata_stream->transport = channel->transport;
1030
1031         /*
1032          * Since life-time of metadata cache differs from that of
1033          * session, we need to keep our own reference on the transport.
1034          */
1035         if (!try_module_get(metadata_stream->transport->owner)) {
1036                 printk(KERN_WARNING "LTT : Can't lock transport module.\n");
1037                 ret = -EINVAL;
1038                 goto notransport;
1039         }
1040
1041         if (!lttng_kref_get(&session->metadata_cache->refcount)) {
1042                 ret = -EOVERFLOW;
1043                 goto kref_error;
1044         }
1045
1046         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
1047                         &lttng_metadata_ring_buffer_file_operations);
1048         if (ret < 0)
1049                 goto fd_error;
1050
1051         list_add(&metadata_stream->list,
1052                 &session->metadata_cache->metadata_stream);
1053         return ret;
1054
1055 fd_error:
1056         kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
1057 kref_error:
1058         module_put(metadata_stream->transport->owner);
1059 notransport:
1060         kfree(metadata_stream);
1061 nomem:
1062         channel->ops->buffer_read_close(buf);
1063         return ret;
1064 }
1065
1066 static
1067 int lttng_abi_create_event(struct file *channel_file,
1068                            struct lttng_kernel_event *event_param)
1069 {
1070         struct lttng_channel *channel = channel_file->private_data;
1071         int event_fd, ret;
1072         struct file *event_file;
1073         void *priv;
1074
1075         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1076         switch (event_param->instrumentation) {
1077         case LTTNG_KERNEL_KRETPROBE:
1078                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1079                 break;
1080         case LTTNG_KERNEL_KPROBE:
1081                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1082                 break;
1083         case LTTNG_KERNEL_FUNCTION:
1084                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
1085                 break;
1086         default:
1087                 break;
1088         }
1089         event_fd = lttng_get_unused_fd();
1090         if (event_fd < 0) {
1091                 ret = event_fd;
1092                 goto fd_error;
1093         }
1094         event_file = anon_inode_getfile("[lttng_event]",
1095                                         &lttng_event_fops,
1096                                         NULL, O_RDWR);
1097         if (IS_ERR(event_file)) {
1098                 ret = PTR_ERR(event_file);
1099                 goto file_error;
1100         }
1101         /* The event holds a reference on the channel */
1102         if (!atomic_long_add_unless(&channel_file->f_count, 1, LONG_MAX)) {
1103                 ret = -EOVERFLOW;
1104                 goto refcount_error;
1105         }
1106         if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
1107                         || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
1108                 struct lttng_enabler *enabler;
1109
1110                 if (strutils_is_star_glob_pattern(event_param->name)) {
1111                         /*
1112                          * If the event name is a star globbing pattern,
1113                          * we create the special star globbing enabler.
1114                          */
1115                         enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
1116                                 event_param, channel);
1117                 } else {
1118                         enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
1119                                 event_param, channel);
1120                 }
1121                 priv = enabler;
1122         } else {
1123                 struct lttng_event *event;
1124
1125                 /*
1126                  * We tolerate no failure path after event creation. It
1127                  * will stay invariant for the rest of the session.
1128                  */
1129                 event = lttng_event_create(channel, event_param,
1130                                 NULL, NULL,
1131                                 event_param->instrumentation);
1132                 WARN_ON_ONCE(!event);
1133                 if (IS_ERR(event)) {
1134                         ret = PTR_ERR(event);
1135                         goto event_error;
1136                 }
1137                 priv = event;
1138         }
1139         event_file->private_data = priv;
1140         fd_install(event_fd, event_file);
1141         return event_fd;
1142
1143 event_error:
1144         atomic_long_dec(&channel_file->f_count);
1145 refcount_error:
1146         fput(event_file);
1147 file_error:
1148         put_unused_fd(event_fd);
1149 fd_error:
1150         return ret;
1151 }
1152
1153 /**
1154  *      lttng_channel_ioctl - lttng syscall through ioctl
1155  *
1156  *      @file: the file
1157  *      @cmd: the command
1158  *      @arg: command arg
1159  *
1160  *      This ioctl implements lttng commands:
1161  *      LTTNG_KERNEL_STREAM
1162  *              Returns an event stream file descriptor or failure.
1163  *              (typically, one event stream records events from one CPU)
1164  *      LTTNG_KERNEL_EVENT
1165  *              Returns an event file descriptor or failure.
1166  *      LTTNG_KERNEL_CONTEXT
1167  *              Prepend a context field to each event in the channel
1168  *      LTTNG_KERNEL_ENABLE
1169  *              Enable recording for events in this channel (weak enable)
1170  *      LTTNG_KERNEL_DISABLE
1171  *              Disable recording for events in this channel (strong disable)
1172  *
1173  * Channel and event file descriptors also hold a reference on the session.
1174  */
1175 static
1176 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1177 {
1178         struct lttng_channel *channel = file->private_data;
1179
1180         switch (cmd) {
1181         case LTTNG_KERNEL_OLD_STREAM:
1182         case LTTNG_KERNEL_STREAM:
1183                 return lttng_abi_open_stream(file);
1184         case LTTNG_KERNEL_OLD_EVENT:
1185         {
1186                 struct lttng_kernel_event *uevent_param;
1187                 struct lttng_kernel_old_event *old_uevent_param;
1188                 int ret;
1189
1190                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
1191                                 GFP_KERNEL);
1192                 if (!uevent_param) {
1193                         ret = -ENOMEM;
1194                         goto old_event_end;
1195                 }
1196                 old_uevent_param = kmalloc(
1197                                 sizeof(struct lttng_kernel_old_event),
1198                                 GFP_KERNEL);
1199                 if (!old_uevent_param) {
1200                         ret = -ENOMEM;
1201                         goto old_event_error_free_param;
1202                 }
1203                 if (copy_from_user(old_uevent_param,
1204                                 (struct lttng_kernel_old_event __user *) arg,
1205                                 sizeof(struct lttng_kernel_old_event))) {
1206                         ret = -EFAULT;
1207                         goto old_event_error_free_old_param;
1208                 }
1209
1210                 memcpy(uevent_param->name, old_uevent_param->name,
1211                                 sizeof(uevent_param->name));
1212                 uevent_param->instrumentation =
1213                         old_uevent_param->instrumentation;
1214
1215                 switch (old_uevent_param->instrumentation) {
1216                 case LTTNG_KERNEL_KPROBE:
1217                         uevent_param->u.kprobe.addr =
1218                                 old_uevent_param->u.kprobe.addr;
1219                         uevent_param->u.kprobe.offset =
1220                                 old_uevent_param->u.kprobe.offset;
1221                         memcpy(uevent_param->u.kprobe.symbol_name,
1222                                 old_uevent_param->u.kprobe.symbol_name,
1223                                 sizeof(uevent_param->u.kprobe.symbol_name));
1224                         break;
1225                 case LTTNG_KERNEL_KRETPROBE:
1226                         uevent_param->u.kretprobe.addr =
1227                                 old_uevent_param->u.kretprobe.addr;
1228                         uevent_param->u.kretprobe.offset =
1229                                 old_uevent_param->u.kretprobe.offset;
1230                         memcpy(uevent_param->u.kretprobe.symbol_name,
1231                                 old_uevent_param->u.kretprobe.symbol_name,
1232                                 sizeof(uevent_param->u.kretprobe.symbol_name));
1233                         break;
1234                 case LTTNG_KERNEL_FUNCTION:
1235                         memcpy(uevent_param->u.ftrace.symbol_name,
1236                                         old_uevent_param->u.ftrace.symbol_name,
1237                                         sizeof(uevent_param->u.ftrace.symbol_name));
1238                         break;
1239                 default:
1240                         break;
1241                 }
1242                 ret = lttng_abi_create_event(file, uevent_param);
1243
1244 old_event_error_free_old_param:
1245                 kfree(old_uevent_param);
1246 old_event_error_free_param:
1247                 kfree(uevent_param);
1248 old_event_end:
1249                 return ret;
1250         }
1251         case LTTNG_KERNEL_EVENT:
1252         {
1253                 struct lttng_kernel_event uevent_param;
1254
1255                 if (copy_from_user(&uevent_param,
1256                                 (struct lttng_kernel_event __user *) arg,
1257                                 sizeof(uevent_param)))
1258                         return -EFAULT;
1259                 return lttng_abi_create_event(file, &uevent_param);
1260         }
1261         case LTTNG_KERNEL_OLD_CONTEXT:
1262         {
1263                 struct lttng_kernel_context *ucontext_param;
1264                 struct lttng_kernel_old_context *old_ucontext_param;
1265                 int ret;
1266
1267                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1268                                 GFP_KERNEL);
1269                 if (!ucontext_param) {
1270                         ret = -ENOMEM;
1271                         goto old_ctx_end;
1272                 }
1273                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1274                                 GFP_KERNEL);
1275                 if (!old_ucontext_param) {
1276                         ret = -ENOMEM;
1277                         goto old_ctx_error_free_param;
1278                 }
1279
1280                 if (copy_from_user(old_ucontext_param,
1281                                 (struct lttng_kernel_old_context __user *) arg,
1282                                 sizeof(struct lttng_kernel_old_context))) {
1283                         ret = -EFAULT;
1284                         goto old_ctx_error_free_old_param;
1285                 }
1286                 ucontext_param->ctx = old_ucontext_param->ctx;
1287                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1288                                 sizeof(ucontext_param->padding));
1289                 /* only type that uses the union */
1290                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1291                         ucontext_param->u.perf_counter.type =
1292                                 old_ucontext_param->u.perf_counter.type;
1293                         ucontext_param->u.perf_counter.config =
1294                                 old_ucontext_param->u.perf_counter.config;
1295                         memcpy(ucontext_param->u.perf_counter.name,
1296                                 old_ucontext_param->u.perf_counter.name,
1297                                 sizeof(ucontext_param->u.perf_counter.name));
1298                 }
1299
1300                 ret = lttng_abi_add_context(file,
1301                                 ucontext_param,
1302                                 &channel->ctx, channel->session);
1303
1304 old_ctx_error_free_old_param:
1305                 kfree(old_ucontext_param);
1306 old_ctx_error_free_param:
1307                 kfree(ucontext_param);
1308 old_ctx_end:
1309                 return ret;
1310         }
1311         case LTTNG_KERNEL_CONTEXT:
1312         {
1313                 struct lttng_kernel_context ucontext_param;
1314
1315                 if (copy_from_user(&ucontext_param,
1316                                 (struct lttng_kernel_context __user *) arg,
1317                                 sizeof(ucontext_param)))
1318                         return -EFAULT;
1319                 return lttng_abi_add_context(file,
1320                                 &ucontext_param,
1321                                 &channel->ctx, channel->session);
1322         }
1323         case LTTNG_KERNEL_OLD_ENABLE:
1324         case LTTNG_KERNEL_ENABLE:
1325                 return lttng_channel_enable(channel);
1326         case LTTNG_KERNEL_OLD_DISABLE:
1327         case LTTNG_KERNEL_DISABLE:
1328                 return lttng_channel_disable(channel);
1329         case LTTNG_KERNEL_SYSCALL_MASK:
1330                 return lttng_channel_syscall_mask(channel,
1331                         (struct lttng_kernel_syscall_mask __user *) arg);
1332         default:
1333                 return -ENOIOCTLCMD;
1334         }
1335 }
1336
1337 /**
1338  *      lttng_metadata_ioctl - lttng syscall through ioctl
1339  *
1340  *      @file: the file
1341  *      @cmd: the command
1342  *      @arg: command arg
1343  *
1344  *      This ioctl implements lttng commands:
1345  *      LTTNG_KERNEL_STREAM
1346  *              Returns an event stream file descriptor or failure.
1347  *
1348  * Channel and event file descriptors also hold a reference on the session.
1349  */
1350 static
1351 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1352 {
1353         switch (cmd) {
1354         case LTTNG_KERNEL_OLD_STREAM:
1355         case LTTNG_KERNEL_STREAM:
1356                 return lttng_abi_open_metadata_stream(file);
1357         default:
1358                 return -ENOIOCTLCMD;
1359         }
1360 }
1361
1362 /**
1363  *      lttng_channel_poll - lttng stream addition/removal monitoring
1364  *
1365  *      @file: the file
1366  *      @wait: poll table
1367  */
1368 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1369 {
1370         struct lttng_channel *channel = file->private_data;
1371         unsigned int mask = 0;
1372
1373         if (file->f_mode & FMODE_READ) {
1374                 poll_wait_set_exclusive(wait);
1375                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1376                           wait);
1377
1378                 if (channel->ops->is_disabled(channel->chan))
1379                         return POLLERR;
1380                 if (channel->ops->is_finalized(channel->chan))
1381                         return POLLHUP;
1382                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1383                         return POLLIN | POLLRDNORM;
1384                 return 0;
1385         }
1386         return mask;
1387
1388 }
1389
1390 static
1391 int lttng_channel_release(struct inode *inode, struct file *file)
1392 {
1393         struct lttng_channel *channel = file->private_data;
1394
1395         if (channel)
1396                 fput(channel->session->file);
1397         return 0;
1398 }
1399
1400 static
1401 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1402 {
1403         struct lttng_channel *channel = file->private_data;
1404
1405         if (channel) {
1406                 fput(channel->session->file);
1407                 lttng_metadata_channel_destroy(channel);
1408         }
1409
1410         return 0;
1411 }
1412
1413 static const struct file_operations lttng_channel_fops = {
1414         .owner = THIS_MODULE,
1415         .release = lttng_channel_release,
1416         .poll = lttng_channel_poll,
1417         .unlocked_ioctl = lttng_channel_ioctl,
1418 #ifdef CONFIG_COMPAT
1419         .compat_ioctl = lttng_channel_ioctl,
1420 #endif
1421 };
1422
1423 static const struct file_operations lttng_metadata_fops = {
1424         .owner = THIS_MODULE,
1425         .release = lttng_metadata_channel_release,
1426         .unlocked_ioctl = lttng_metadata_ioctl,
1427 #ifdef CONFIG_COMPAT
1428         .compat_ioctl = lttng_metadata_ioctl,
1429 #endif
1430 };
1431
1432 /**
1433  *      lttng_event_ioctl - lttng syscall through ioctl
1434  *
1435  *      @file: the file
1436  *      @cmd: the command
1437  *      @arg: command arg
1438  *
1439  *      This ioctl implements lttng commands:
1440  *      LTTNG_KERNEL_CONTEXT
1441  *              Prepend a context field to each record of this event
1442  *      LTTNG_KERNEL_ENABLE
1443  *              Enable recording for this event (weak enable)
1444  *      LTTNG_KERNEL_DISABLE
1445  *              Disable recording for this event (strong disable)
1446  */
1447 static
1448 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1449 {
1450         struct lttng_event *event;
1451         struct lttng_enabler *enabler;
1452         enum lttng_event_type *evtype = file->private_data;
1453
1454         switch (cmd) {
1455         case LTTNG_KERNEL_OLD_CONTEXT:
1456         {
1457                 /* Not implemented */
1458                 return -ENOSYS;
1459         }
1460         case LTTNG_KERNEL_CONTEXT:
1461         {
1462                 /* Not implemented */
1463                 return -ENOSYS;
1464         }
1465         case LTTNG_KERNEL_OLD_ENABLE:
1466         case LTTNG_KERNEL_ENABLE:
1467                 switch (*evtype) {
1468                 case LTTNG_TYPE_EVENT:
1469                         event = file->private_data;
1470                         return lttng_event_enable(event);
1471                 case LTTNG_TYPE_ENABLER:
1472                         enabler = file->private_data;
1473                         return lttng_enabler_enable(enabler);
1474                 default:
1475                         WARN_ON_ONCE(1);
1476                         return -ENOSYS;
1477                 }
1478         case LTTNG_KERNEL_OLD_DISABLE:
1479         case LTTNG_KERNEL_DISABLE:
1480                 switch (*evtype) {
1481                 case LTTNG_TYPE_EVENT:
1482                         event = file->private_data;
1483                         return lttng_event_disable(event);
1484                 case LTTNG_TYPE_ENABLER:
1485                         enabler = file->private_data;
1486                         return lttng_enabler_disable(enabler);
1487                 default:
1488                         WARN_ON_ONCE(1);
1489                         return -ENOSYS;
1490                 }
1491         case LTTNG_KERNEL_FILTER:
1492                 switch (*evtype) {
1493                 case LTTNG_TYPE_EVENT:
1494                         return -EINVAL;
1495                 case LTTNG_TYPE_ENABLER:
1496                 {
1497                         enabler = file->private_data;
1498                         return lttng_enabler_attach_bytecode(enabler,
1499                                 (struct lttng_kernel_filter_bytecode __user *) arg);
1500                 }
1501                 default:
1502                         WARN_ON_ONCE(1);
1503                         return -ENOSYS;
1504                 }
1505         case LTTNG_KERNEL_ADD_CALLSITE:
1506                 switch (*evtype) {
1507                 case LTTNG_TYPE_EVENT:
1508                         event = file->private_data;
1509                         return lttng_event_add_callsite(event,
1510                                 (struct lttng_kernel_event_callsite __user *) arg);
1511                 case LTTNG_TYPE_ENABLER:
1512                         return -EINVAL;
1513                 }
1514         default:
1515                 return -ENOIOCTLCMD;
1516         }
1517 }
1518
1519 static
1520 int lttng_event_release(struct inode *inode, struct file *file)
1521 {
1522         struct lttng_event *event;
1523         struct lttng_enabler *enabler;
1524         enum lttng_event_type *evtype = file->private_data;
1525
1526         if (!evtype)
1527                 return 0;
1528
1529         switch (*evtype) {
1530         case LTTNG_TYPE_EVENT:
1531                 event = file->private_data;
1532                 if (event)
1533                         fput(event->chan->file);
1534                 break;
1535         case LTTNG_TYPE_ENABLER:
1536                 enabler = file->private_data;
1537                 if (enabler)
1538                         fput(enabler->chan->file);
1539                 break;
1540         default:
1541                 WARN_ON_ONCE(1);
1542                 break;
1543         }
1544
1545         return 0;
1546 }
1547
1548 /* TODO: filter control ioctl */
1549 static const struct file_operations lttng_event_fops = {
1550         .owner = THIS_MODULE,
1551         .release = lttng_event_release,
1552         .unlocked_ioctl = lttng_event_ioctl,
1553 #ifdef CONFIG_COMPAT
1554         .compat_ioctl = lttng_event_ioctl,
1555 #endif
1556 };
1557
1558 static int put_u64(uint64_t val, unsigned long arg)
1559 {
1560         return put_user(val, (uint64_t __user *) arg);
1561 }
1562
1563 static long lttng_stream_ring_buffer_ioctl(struct file *filp,
1564                 unsigned int cmd, unsigned long arg)
1565 {
1566         struct lib_ring_buffer *buf = filp->private_data;
1567         struct channel *chan = buf->backend.chan;
1568         const struct lib_ring_buffer_config *config = &chan->backend.config;
1569         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1570         int ret;
1571
1572         if (atomic_read(&chan->record_disabled))
1573                 return -EIO;
1574
1575         switch (cmd) {
1576         case LTTNG_RING_BUFFER_GET_TIMESTAMP_BEGIN:
1577         {
1578                 uint64_t ts;
1579
1580                 ret = ops->timestamp_begin(config, buf, &ts);
1581                 if (ret < 0)
1582                         goto error;
1583                 return put_u64(ts, arg);
1584         }
1585         case LTTNG_RING_BUFFER_GET_TIMESTAMP_END:
1586         {
1587                 uint64_t ts;
1588
1589                 ret = ops->timestamp_end(config, buf, &ts);
1590                 if (ret < 0)
1591                         goto error;
1592                 return put_u64(ts, arg);
1593         }
1594         case LTTNG_RING_BUFFER_GET_EVENTS_DISCARDED:
1595         {
1596                 uint64_t ed;
1597
1598                 ret = ops->events_discarded(config, buf, &ed);
1599                 if (ret < 0)
1600                         goto error;
1601                 return put_u64(ed, arg);
1602         }
1603         case LTTNG_RING_BUFFER_GET_CONTENT_SIZE:
1604         {
1605                 uint64_t cs;
1606
1607                 ret = ops->content_size(config, buf, &cs);
1608                 if (ret < 0)
1609                         goto error;
1610                 return put_u64(cs, arg);
1611         }
1612         case LTTNG_RING_BUFFER_GET_PACKET_SIZE:
1613         {
1614                 uint64_t ps;
1615
1616                 ret = ops->packet_size(config, buf, &ps);
1617                 if (ret < 0)
1618                         goto error;
1619                 return put_u64(ps, arg);
1620         }
1621         case LTTNG_RING_BUFFER_GET_STREAM_ID:
1622         {
1623                 uint64_t si;
1624
1625                 ret = ops->stream_id(config, buf, &si);
1626                 if (ret < 0)
1627                         goto error;
1628                 return put_u64(si, arg);
1629         }
1630         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1631         {
1632                 uint64_t ts;
1633
1634                 ret = ops->current_timestamp(config, buf, &ts);
1635                 if (ret < 0)
1636                         goto error;
1637                 return put_u64(ts, arg);
1638         }
1639         case LTTNG_RING_BUFFER_GET_SEQ_NUM:
1640         {
1641                 uint64_t seq;
1642
1643                 ret = ops->sequence_number(config, buf, &seq);
1644                 if (ret < 0)
1645                         goto error;
1646                 return put_u64(seq, arg);
1647         }
1648         case LTTNG_RING_BUFFER_INSTANCE_ID:
1649         {
1650                 uint64_t id;
1651
1652                 ret = ops->instance_id(config, buf, &id);
1653                 if (ret < 0)
1654                         goto error;
1655                 return put_u64(id, arg);
1656         }
1657         default:
1658                 return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
1659                                 cmd, arg);
1660         }
1661
1662 error:
1663         return -ENOSYS;
1664 }
1665
1666 #ifdef CONFIG_COMPAT
1667 static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
1668                 unsigned int cmd, unsigned long arg)
1669 {
1670         struct lib_ring_buffer *buf = filp->private_data;
1671         struct channel *chan = buf->backend.chan;
1672         const struct lib_ring_buffer_config *config = &chan->backend.config;
1673         const struct lttng_channel_ops *ops = chan->backend.priv_ops;
1674         int ret;
1675
1676         if (atomic_read(&chan->record_disabled))
1677                 return -EIO;
1678
1679         switch (cmd) {
1680         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_BEGIN:
1681         {
1682                 uint64_t ts;
1683
1684                 ret = ops->timestamp_begin(config, buf, &ts);
1685                 if (ret < 0)
1686                         goto error;
1687                 return put_u64(ts, arg);
1688         }
1689         case LTTNG_RING_BUFFER_COMPAT_GET_TIMESTAMP_END:
1690         {
1691                 uint64_t ts;
1692
1693                 ret = ops->timestamp_end(config, buf, &ts);
1694                 if (ret < 0)
1695                         goto error;
1696                 return put_u64(ts, arg);
1697         }
1698         case LTTNG_RING_BUFFER_COMPAT_GET_EVENTS_DISCARDED:
1699         {
1700                 uint64_t ed;
1701
1702                 ret = ops->events_discarded(config, buf, &ed);
1703                 if (ret < 0)
1704                         goto error;
1705                 return put_u64(ed, arg);
1706         }
1707         case LTTNG_RING_BUFFER_COMPAT_GET_CONTENT_SIZE:
1708         {
1709                 uint64_t cs;
1710
1711                 ret = ops->content_size(config, buf, &cs);
1712                 if (ret < 0)
1713                         goto error;
1714                 return put_u64(cs, arg);
1715         }
1716         case LTTNG_RING_BUFFER_COMPAT_GET_PACKET_SIZE:
1717         {
1718                 uint64_t ps;
1719
1720                 ret = ops->packet_size(config, buf, &ps);
1721                 if (ret < 0)
1722                         goto error;
1723                 return put_u64(ps, arg);
1724         }
1725         case LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID:
1726         {
1727                 uint64_t si;
1728
1729                 ret = ops->stream_id(config, buf, &si);
1730                 if (ret < 0)
1731                         goto error;
1732                 return put_u64(si, arg);
1733         }
1734         case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
1735         {
1736                 uint64_t ts;
1737
1738                 ret = ops->current_timestamp(config, buf, &ts);
1739                 if (ret < 0)
1740                         goto error;
1741                 return put_u64(ts, arg);
1742         }
1743         case LTTNG_RING_BUFFER_COMPAT_GET_SEQ_NUM:
1744         {
1745                 uint64_t seq;
1746
1747                 ret = ops->sequence_number(config, buf, &seq);
1748                 if (ret < 0)
1749                         goto error;
1750                 return put_u64(seq, arg);
1751         }
1752         case LTTNG_RING_BUFFER_COMPAT_INSTANCE_ID:
1753         {
1754                 uint64_t id;
1755
1756                 ret = ops->instance_id(config, buf, &id);
1757                 if (ret < 0)
1758                         goto error;
1759                 return put_u64(id, arg);
1760         }
1761         default:
1762                 return lib_ring_buffer_file_operations.compat_ioctl(filp,
1763                                 cmd, arg);
1764         }
1765
1766 error:
1767         return -ENOSYS;
1768 }
1769 #endif /* CONFIG_COMPAT */
1770
1771 static void lttng_stream_override_ring_buffer_fops(void)
1772 {
1773         lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
1774         lttng_stream_ring_buffer_file_operations.open =
1775                 lib_ring_buffer_file_operations.open;
1776         lttng_stream_ring_buffer_file_operations.release =
1777                 lib_ring_buffer_file_operations.release;
1778         lttng_stream_ring_buffer_file_operations.poll =
1779                 lib_ring_buffer_file_operations.poll;
1780         lttng_stream_ring_buffer_file_operations.splice_read =
1781                 lib_ring_buffer_file_operations.splice_read;
1782         lttng_stream_ring_buffer_file_operations.mmap =
1783                 lib_ring_buffer_file_operations.mmap;
1784         lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
1785                 lttng_stream_ring_buffer_ioctl;
1786         lttng_stream_ring_buffer_file_operations.llseek =
1787                 lib_ring_buffer_file_operations.llseek;
1788 #ifdef CONFIG_COMPAT
1789         lttng_stream_ring_buffer_file_operations.compat_ioctl =
1790                 lttng_stream_ring_buffer_compat_ioctl;
1791 #endif
1792 }
1793
1794 int __init lttng_abi_init(void)
1795 {
1796         int ret = 0;
1797
1798         wrapper_vmalloc_sync_all();
1799         lttng_clock_ref();
1800
1801         ret = lttng_tp_mempool_init();
1802         if (ret) {
1803                 goto error;
1804         }
1805
1806         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1807                                         &lttng_fops, NULL);
1808
1809         if (!lttng_proc_dentry) {
1810                 printk(KERN_ERR "Error creating LTTng control file\n");
1811                 ret = -ENOMEM;
1812                 goto error;
1813         }
1814         lttng_stream_override_ring_buffer_fops();
1815         return 0;
1816
1817 error:
1818         lttng_tp_mempool_destroy();
1819         lttng_clock_unref();
1820         return ret;
1821 }
1822
1823 /* No __exit annotation because used by init error path too. */
1824 void lttng_abi_exit(void)
1825 {
1826         lttng_tp_mempool_destroy();
1827         lttng_clock_unref();
1828         if (lttng_proc_dentry)
1829                 remove_proc_entry("lttng", NULL);
1830 }