src/lttng-syscalls.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-syscalls.c
   4  *
   5  * LTTng syscall probes.
   6  *
   7  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/compat.h>
  13 #include <linux/err.h>
  14 #include <linux/bitmap.h>
  15 #include <linux/in.h>
  16 #include <linux/in6.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/stringify.h>
  19 #include <linux/file.h>
  20 #include <linux/anon_inodes.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/mman.h>
  23 #include <asm/ptrace.h>
  24 #include <asm/syscall.h>
  25
  26 #include <lttng/bitfield.h>
  27 #include <wrapper/tracepoint.h>
  28 #include <wrapper/file.h>
  29 #include <wrapper/rcu.h>
  30 #include <wrapper/syscall.h>
  31 #include <lttng/events.h>
  32 #include <lttng/events-internal.h>
  33 #include <lttng/utils.h>
  34
  35 #include "lttng-syscalls.h"
  36
  37 #ifndef CONFIG_COMPAT
  38 # ifndef is_compat_task
  39 #  define is_compat_task()      (0)
  40 # endif
  41 #endif
  42
  43 /* in_compat_syscall appears in kernel 4.6. */
  44 #ifndef in_compat_syscall
  45  #define in_compat_syscall()    is_compat_task()
  46 #endif
  47
  48 enum sc_type {
  49         SC_TYPE_ENTRY,
  50         SC_TYPE_EXIT,
  51         SC_TYPE_COMPAT_ENTRY,
  52         SC_TYPE_COMPAT_EXIT,
  53 };
  54
  55 #define SYSCALL_ENTRY_TOK               syscall_entry_
  56 #define COMPAT_SYSCALL_ENTRY_TOK        compat_syscall_entry_
  57 #define SYSCALL_EXIT_TOK                syscall_exit_
  58 #define COMPAT_SYSCALL_EXIT_TOK         compat_syscall_exit_
  59
  60 #define SYSCALL_ENTRY_STR               __stringify(SYSCALL_ENTRY_TOK)
  61 #define COMPAT_SYSCALL_ENTRY_STR        __stringify(COMPAT_SYSCALL_ENTRY_TOK)
  62 #define SYSCALL_EXIT_STR                __stringify(SYSCALL_EXIT_TOK)
  63 #define COMPAT_SYSCALL_EXIT_STR         __stringify(COMPAT_SYSCALL_EXIT_TOK)
  64
  65 void syscall_entry_event_probe(void *__data, struct pt_regs *regs, long id);
  66 void syscall_exit_event_probe(void *__data, struct pt_regs *regs, long ret);
  67
  68 /*
  69  * Forward declarations for old kernels.
  70  */
  71 struct mmsghdr;
  72 struct rlimit64;
  73 struct oldold_utsname;
  74 struct old_utsname;
  75 struct sel_arg_struct;
  76 struct mmap_arg_struct;
  77 struct file_handle;
  78 struct user_msghdr;
  79
  80 /*
  81  * Forward declaration for kernels >= 5.6
  82  */
  83 struct timex;
  84 struct timeval;
  85 struct itimerval;
  86 struct itimerspec;
  87
  88 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0))
  89 typedef __kernel_old_time_t time_t;
  90 #endif
  91
  92 #ifdef IA32_NR_syscalls
  93 #define NR_compat_syscalls IA32_NR_syscalls
  94 #else
  95 #define NR_compat_syscalls NR_syscalls
  96 #endif
  97
  98 /*
  99  * Create LTTng tracepoint probes.
 100  */
 101 #define LTTNG_PACKAGE_BUILD
 102 #define CREATE_TRACE_POINTS
 103 #define TP_MODULE_NOINIT
 104 #define TRACE_INCLUDE_PATH instrumentation/syscalls/headers
 105
 106 #define PARAMS(args...) args
 107
 108 /* Handle unknown syscalls */
 109 #undef TRACE_SYSTEM
 110 #define TRACE_SYSTEM syscalls_unknown
 111 #include <instrumentation/syscalls/headers/syscalls_unknown.h>
 112 #undef TRACE_SYSTEM
 113
 114 #undef TP_PROBE_CB
 115
 116 extern const struct trace_syscall_table sc_table;
 117 extern const struct trace_syscall_table compat_sc_table;
 118
 119 /* Event syscall exit table */
 120 extern const struct trace_syscall_table sc_exit_table;
 121 extern const struct trace_syscall_table compat_sc_exit_table;
 122
 123
 124 #undef SC_EXIT
 125
 126 #undef CREATE_SYSCALL_TABLE
 127
 128 struct lttng_syscall_filter {
 129         DECLARE_BITMAP(sc_entry, NR_syscalls);
 130         DECLARE_BITMAP(sc_exit, NR_syscalls);
 131         DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
 132         DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
 133 };
 134
 135 static void syscall_entry_event_unknown(struct hlist_head *unknown_action_list_head,
 136         struct pt_regs *regs, long id)
 137 {
 138         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 139         struct lttng_kernel_event_common_private *event_priv;
 140
 141         lttng_syscall_get_arguments(current, regs, args);
 142         lttng_hlist_for_each_entry_rcu(event_priv, unknown_action_list_head, u.syscall.node) {
 143                 if (unlikely(in_compat_syscall()))
 144                         __event_probe__compat_syscall_entry_unknown(event_priv->pub, id, args);
 145                 else
 146                         __event_probe__syscall_entry_unknown(event_priv->pub, id, args);
 147         }
 148 }
 149
 150 static __always_inline
 151 void syscall_entry_event_call_func(struct hlist_head *action_list,
 152                 void *func, unsigned int nrargs,
 153                 struct pt_regs *regs)
 154 {
 155         struct lttng_kernel_event_common_private *event_priv;
 156
 157         switch (nrargs) {
 158         case 0:
 159         {
 160                 void (*fptr)(void *__data) = func;
 161
 162                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 163                         fptr(event_priv->pub);
 164                 break;
 165         }
 166         case 1:
 167         {
 168                 void (*fptr)(void *__data, unsigned long arg0) = func;
 169                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 170
 171                 lttng_syscall_get_arguments(current, regs, args);
 172                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 173                         fptr(event_priv->pub, args[0]);
 174                 break;
 175         }
 176         case 2:
 177         {
 178                 void (*fptr)(void *__data,
 179                         unsigned long arg0,
 180                         unsigned long arg1) = func;
 181                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 182
 183                 lttng_syscall_get_arguments(current, regs, args);
 184                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 185                         fptr(event_priv->pub, args[0], args[1]);
 186                 break;
 187         }
 188         case 3:
 189         {
 190                 void (*fptr)(void *__data,
 191                         unsigned long arg0,
 192                         unsigned long arg1,
 193                         unsigned long arg2) = func;
 194                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 195
 196                 lttng_syscall_get_arguments(current, regs, args);
 197                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 198                         fptr(event_priv->pub, args[0], args[1], args[2]);
 199                 break;
 200         }
 201         case 4:
 202         {
 203                 void (*fptr)(void *__data,
 204                         unsigned long arg0,
 205                         unsigned long arg1,
 206                         unsigned long arg2,
 207                         unsigned long arg3) = func;
 208                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 209
 210                 lttng_syscall_get_arguments(current, regs, args);
 211                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 212                         fptr(event_priv->pub, args[0], args[1], args[2], args[3]);
 213                 break;
 214         }
 215         case 5:
 216         {
 217                 void (*fptr)(void *__data,
 218                         unsigned long arg0,
 219                         unsigned long arg1,
 220                         unsigned long arg2,
 221                         unsigned long arg3,
 222                         unsigned long arg4) = func;
 223                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 224
 225                 lttng_syscall_get_arguments(current, regs, args);
 226                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 227                         fptr(event_priv->pub, args[0], args[1], args[2], args[3], args[4]);
 228                 break;
 229         }
 230         case 6:
 231         {
 232                 void (*fptr)(void *__data,
 233                         unsigned long arg0,
 234                         unsigned long arg1,
 235                         unsigned long arg2,
 236                         unsigned long arg3,
 237                         unsigned long arg4,
 238                         unsigned long arg5) = func;
 239                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 240
 241                 lttng_syscall_get_arguments(current, regs, args);
 242                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 243                         fptr(event_priv->pub, args[0], args[1], args[2],
 244                              args[3], args[4], args[5]);
 245                 break;
 246         }
 247         default:
 248                 break;
 249         }
 250 }
 251
 252 void syscall_entry_event_probe(void *__data, struct pt_regs *regs, long id)
 253 {
 254         struct lttng_kernel_syscall_table *syscall_table = __data;
 255         struct hlist_head *action_list, *unknown_action_list;
 256         const struct trace_syscall_entry *table, *entry;
 257         size_t table_len;
 258
 259         if (unlikely(in_compat_syscall())) {
 260                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 261
 262                 if (id < 0 || id >= NR_compat_syscalls
 263                         || (!READ_ONCE(syscall_table->syscall_all_entry) && !test_bit(id, filter->sc_compat_entry))) {
 264                         /* System call filtered out. */
 265                         return;
 266                 }
 267                 table = compat_sc_table.table;
 268                 table_len = compat_sc_table.len;
 269                 unknown_action_list = &syscall_table->compat_unknown_syscall_dispatch;
 270         } else {
 271                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 272
 273                 if (id < 0 || id >= NR_syscalls
 274                         || (!READ_ONCE(syscall_table->syscall_all_entry) && !test_bit(id, filter->sc_entry))) {
 275                         /* System call filtered out. */
 276                         return;
 277                 }
 278                 table = sc_table.table;
 279                 table_len = sc_table.len;
 280                 unknown_action_list = &syscall_table->unknown_syscall_dispatch;
 281         }
 282         if (unlikely(id < 0 || id >= table_len)) {
 283                 syscall_entry_event_unknown(unknown_action_list, regs, id);
 284                 return;
 285         }
 286
 287         entry = &table[id];
 288         if (!entry->event_func) {
 289                 syscall_entry_event_unknown(unknown_action_list, regs, id);
 290                 return;
 291         }
 292
 293         if (unlikely(in_compat_syscall())) {
 294                 action_list = &syscall_table->compat_syscall_dispatch[id];
 295         } else {
 296                 action_list = &syscall_table->syscall_dispatch[id];
 297         }
 298         if (unlikely(hlist_empty(action_list)))
 299                 return;
 300
 301         syscall_entry_event_call_func(action_list, entry->event_func, entry->nrargs, regs);
 302 }
 303
 304 static void syscall_exit_event_unknown(struct hlist_head *unknown_action_list_head,
 305         struct pt_regs *regs, long id, long ret)
 306 {
 307         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 308         struct lttng_kernel_event_common_private *event_priv;
 309
 310         lttng_syscall_get_arguments(current, regs, args);
 311         lttng_hlist_for_each_entry_rcu(event_priv, unknown_action_list_head, u.syscall.node) {
 312                 if (unlikely(in_compat_syscall()))
 313                         __event_probe__compat_syscall_exit_unknown(event_priv->pub, id, ret,
 314                                 args);
 315                 else
 316                         __event_probe__syscall_exit_unknown(event_priv->pub, id, ret, args);
 317         }
 318 }
 319
 320 static __always_inline
 321 void syscall_exit_event_call_func(struct hlist_head *action_list,
 322                 void *func, unsigned int nrargs,
 323                 struct pt_regs *regs, long ret)
 324 {
 325         struct lttng_kernel_event_common_private *event_priv;
 326
 327         switch (nrargs) {
 328         case 0:
 329         {
 330                 void (*fptr)(void *__data, long ret) = func;
 331
 332                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 333                         fptr(event_priv->pub, ret);
 334                 break;
 335         }
 336         case 1:
 337         {
 338                 void (*fptr)(void *__data,
 339                         long ret,
 340                         unsigned long arg0) = func;
 341                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 342
 343                 lttng_syscall_get_arguments(current, regs, args);
 344                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 345                         fptr(event_priv->pub, ret, args[0]);
 346                 break;
 347         }
 348         case 2:
 349         {
 350                 void (*fptr)(void *__data,
 351                         long ret,
 352                         unsigned long arg0,
 353                         unsigned long arg1) = func;
 354                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 355
 356                 lttng_syscall_get_arguments(current, regs, args);
 357                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 358                         fptr(event_priv->pub, ret, args[0], args[1]);
 359                 break;
 360         }
 361         case 3:
 362         {
 363                 void (*fptr)(void *__data,
 364                         long ret,
 365                         unsigned long arg0,
 366                         unsigned long arg1,
 367                         unsigned long arg2) = func;
 368                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 369
 370                 lttng_syscall_get_arguments(current, regs, args);
 371                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 372                         fptr(event_priv->pub, ret, args[0], args[1], args[2]);
 373                 break;
 374         }
 375         case 4:
 376         {
 377                 void (*fptr)(void *__data,
 378                         long ret,
 379                         unsigned long arg0,
 380                         unsigned long arg1,
 381                         unsigned long arg2,
 382                         unsigned long arg3) = func;
 383                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 384
 385                 lttng_syscall_get_arguments(current, regs, args);
 386                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 387                         fptr(event_priv->pub, ret, args[0], args[1], args[2], args[3]);
 388                 break;
 389         }
 390         case 5:
 391         {
 392                 void (*fptr)(void *__data,
 393                         long ret,
 394                         unsigned long arg0,
 395                         unsigned long arg1,
 396                         unsigned long arg2,
 397                         unsigned long arg3,
 398                         unsigned long arg4) = func;
 399                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 400
 401                 lttng_syscall_get_arguments(current, regs, args);
 402                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 403                         fptr(event_priv->pub, ret, args[0], args[1], args[2], args[3], args[4]);
 404                 break;
 405         }
 406         case 6:
 407         {
 408                 void (*fptr)(void *__data,
 409                         long ret,
 410                         unsigned long arg0,
 411                         unsigned long arg1,
 412                         unsigned long arg2,
 413                         unsigned long arg3,
 414                         unsigned long arg4,
 415                         unsigned long arg5) = func;
 416                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 417
 418                 lttng_syscall_get_arguments(current, regs, args);
 419                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 420                         fptr(event_priv->pub, ret, args[0], args[1], args[2],
 421                              args[3], args[4], args[5]);
 422                 break;
 423         }
 424         default:
 425                 break;
 426         }
 427 }
 428
 429 void syscall_exit_event_probe(void *__data, struct pt_regs *regs, long ret)
 430 {
 431         struct lttng_kernel_syscall_table *syscall_table = __data;
 432         struct hlist_head *action_list, *unknown_action_list;
 433         const struct trace_syscall_entry *table, *entry;
 434         size_t table_len;
 435         long id;
 436
 437         id = syscall_get_nr(current, regs);
 438
 439         if (unlikely(in_compat_syscall())) {
 440                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 441
 442                 if (id < 0 || id >= NR_compat_syscalls
 443                         || (!READ_ONCE(syscall_table->syscall_all_exit) && !test_bit(id, filter->sc_compat_exit))) {
 444                         /* System call filtered out. */
 445                         return;
 446                 }
 447                 table = compat_sc_exit_table.table;
 448                 table_len = compat_sc_exit_table.len;
 449                 unknown_action_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
 450         } else {
 451                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 452
 453                 if (id < 0 || id >= NR_syscalls
 454                         || (!READ_ONCE(syscall_table->syscall_all_exit) && !test_bit(id, filter->sc_exit))) {
 455                         /* System call filtered out. */
 456                         return;
 457                 }
 458                 table = sc_exit_table.table;
 459                 table_len = sc_exit_table.len;
 460                 unknown_action_list = &syscall_table->unknown_syscall_exit_dispatch;
 461         }
 462         if (unlikely(id < 0 || id >= table_len)) {
 463                 syscall_exit_event_unknown(unknown_action_list, regs, id, ret);
 464                 return;
 465         }
 466
 467         entry = &table[id];
 468         if (!entry->event_func) {
 469                 syscall_exit_event_unknown(unknown_action_list, regs, id, ret);
 470                 return;
 471         }
 472
 473         if (unlikely(in_compat_syscall())) {
 474                 action_list = &syscall_table->compat_syscall_exit_dispatch[id];
 475         } else {
 476                 action_list = &syscall_table->syscall_exit_dispatch[id];
 477         }
 478         if (unlikely(hlist_empty(action_list)))
 479                 return;
 480
 481         syscall_exit_event_call_func(action_list, entry->event_func, entry->nrargs,
 482                                regs, ret);
 483 }
 484
 485 static
 486 struct lttng_kernel_syscall_table *get_syscall_table_from_enabler(struct lttng_event_enabler_common *event_enabler)
 487 {
 488         switch (event_enabler->enabler_type) {
 489         case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
 490         {
 491                 struct lttng_event_recorder_enabler *event_recorder_enabler =
 492                         container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
 493                 return &event_recorder_enabler->chan->priv->parent.syscall_table;
 494         }
 495         case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
 496         {
 497                 struct lttng_event_notifier_enabler *event_notifier_enabler =
 498                         container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
 499                 return &event_notifier_enabler->group->syscall_table;
 500         }
 501         default:
 502                 return NULL;
 503         }
 504 }
 505
 506 static
 507 struct lttng_kernel_syscall_table *get_syscall_table_from_event(struct lttng_kernel_event_common *event)
 508 {
 509         switch (event->type) {
 510         case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
 511         {
 512                 struct lttng_kernel_event_recorder *event_recorder =
 513                         container_of(event, struct lttng_kernel_event_recorder, parent);
 514                 return &event_recorder->chan->priv->parent.syscall_table;
 515         }
 516         case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
 517         {
 518                 struct lttng_kernel_event_notifier *event_notifier =
 519                         container_of(event, struct lttng_kernel_event_notifier, parent);
 520                 return &event_notifier->priv->group->syscall_table;
 521         }
 522         default:
 523                 return NULL;
 524         }
 525 }
 526
 527 /*
 528  * noinline to diminish caller stack size.
 529  * Should be called with sessions lock held.
 530  */
 531 static
 532 int lttng_create_syscall_event_if_missing(const struct trace_syscall_entry *table, size_t table_len,
 533         struct hlist_head *chan_table, struct lttng_event_recorder_enabler *syscall_event_enabler,
 534         enum sc_type type)
 535 {
 536         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(&syscall_event_enabler->parent);
 537         struct lttng_kernel_channel_buffer *chan = syscall_event_enabler->chan;
 538         struct lttng_kernel_session *session = chan->parent.session;
 539         unsigned int i;
 540
 541         /* Allocate events for each syscall matching enabler, insert into table */
 542         for (i = 0; i < table_len; i++) {
 543                 const struct lttng_kernel_event_desc *desc = table[i].desc;
 544                 struct lttng_event_recorder_enabler *event_enabler;
 545                 struct lttng_kernel_abi_event ev;
 546                 struct lttng_kernel_event_recorder_private *event_recorder_priv;
 547                 struct lttng_kernel_event_recorder *event_recorder;
 548                 struct hlist_head *head;
 549                 bool found = false;
 550
 551                 if (!desc) {
 552                         /* Unknown syscall */
 553                         continue;
 554                 }
 555                 if (lttng_desc_match_enabler(desc,
 556                                 lttng_event_recorder_enabler_as_enabler(syscall_event_enabler)) <= 0)
 557                         continue;
 558                 /*
 559                  * Check if already created.
 560                  */
 561                 head = utils_borrow_hash_table_bucket(
 562                         session->priv->events_ht.table, LTTNG_EVENT_HT_SIZE,
 563                         desc->event_name);
 564                 lttng_hlist_for_each_entry(event_recorder_priv, head, hlist) {
 565                         if (event_recorder_priv->parent.desc == desc
 566                                 && get_syscall_table_from_event(event_recorder_priv->parent.pub) == syscall_table)
 567                                 found = true;
 568                 }
 569                 if (found)
 570                         continue;
 571
 572                 /* We need to create an event for this syscall/enabler. */
 573                 memset(&ev, 0, sizeof(ev));
 574                 switch (type) {
 575                 case SC_TYPE_ENTRY:
 576                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 577                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 578                         break;
 579                 case SC_TYPE_EXIT:
 580                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 581                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 582                         break;
 583                 case SC_TYPE_COMPAT_ENTRY:
 584                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 585                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 586                         break;
 587                 case SC_TYPE_COMPAT_EXIT:
 588                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 589                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 590                         break;
 591                 }
 592                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1);
 593                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 594                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 595                 event_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev, chan);
 596                 if (!event_enabler) {
 597                         return -ENOMEM;
 598                 }
 599                 event_recorder = _lttng_kernel_event_recorder_create(event_enabler, desc);
 600                 WARN_ON_ONCE(!event_recorder);
 601                 lttng_event_enabler_destroy(event_enabler);
 602                 if (IS_ERR(event_recorder)) {
 603                         /*
 604                          * If something goes wrong in event registration
 605                          * after the first one, we have no choice but to
 606                          * leave the previous events in there, until
 607                          * deleted by session teardown.
 608                          */
 609                         return PTR_ERR(event_recorder);
 610                 }
 611                 hlist_add_head(&event_recorder->priv->parent.u.syscall.node, &chan_table[i]);
 612         }
 613         return 0;
 614 }
 615
 616 /*
 617  * Should be called with sessions lock held.
 618  */
 619 int lttng_syscalls_register_event(struct lttng_event_recorder_enabler *syscall_event_enabler)
 620 {
 621         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(&syscall_event_enabler->parent);
 622         struct lttng_kernel_abi_event ev;
 623         int ret;
 624
 625         wrapper_vmalloc_sync_mappings();
 626
 627         if (!syscall_table->syscall_dispatch) {
 628                 /* create syscall table mapping syscall to events */
 629                 syscall_table->syscall_dispatch = kzalloc(sizeof(struct hlist_head) * sc_table.len, GFP_KERNEL);
 630                 if (!syscall_table->syscall_dispatch)
 631                         return -ENOMEM;
 632         }
 633         if (!syscall_table->syscall_exit_dispatch) {
 634                 /* create syscall table mapping syscall to events */
 635                 syscall_table->syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * sc_exit_table.len, GFP_KERNEL);
 636                 if (!syscall_table->syscall_exit_dispatch)
 637                         return -ENOMEM;
 638         }
 639
 640
 641 #ifdef CONFIG_COMPAT
 642         if (!syscall_table->compat_syscall_dispatch) {
 643                 /* create syscall table mapping compat syscall to events */
 644                 syscall_table->compat_syscall_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_table.len, GFP_KERNEL);
 645                 if (!syscall_table->compat_syscall_dispatch)
 646                         return -ENOMEM;
 647         }
 648
 649         if (!syscall_table->compat_syscall_exit_dispatch) {
 650                 /* create syscall table mapping compat syscall to events */
 651                 syscall_table->compat_syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_exit_table.len, GFP_KERNEL);
 652                 if (!syscall_table->compat_syscall_exit_dispatch)
 653                         return -ENOMEM;
 654         }
 655 #endif
 656         if (hlist_empty(&syscall_table->unknown_syscall_dispatch)) {
 657                 const struct lttng_kernel_event_desc *desc =
 658                         &__event_desc___syscall_entry_unknown;
 659                 struct lttng_kernel_event_recorder *event_recorder;
 660                 struct lttng_event_recorder_enabler *event_enabler;
 661
 662                 memset(&ev, 0, sizeof(ev));
 663                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN);
 664                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 665                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 666                 ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 667                 ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 668                 event_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev, syscall_event_enabler->chan);
 669                 if (!event_enabler) {
 670                         return -ENOMEM;
 671                 }
 672                 event_recorder = _lttng_kernel_event_recorder_create(event_enabler, desc);
 673                 lttng_event_enabler_destroy(event_enabler);
 674                 WARN_ON_ONCE(!event_recorder);
 675                 if (IS_ERR(event_recorder)) {
 676                         return PTR_ERR(event_recorder);
 677                 }
 678                 hlist_add_head(&event_recorder->priv->parent.u.syscall.node, &syscall_table->unknown_syscall_dispatch);
 679         }
 680
 681         if (hlist_empty(&syscall_table->compat_unknown_syscall_dispatch)) {
 682                 const struct lttng_kernel_event_desc *desc =
 683                         &__event_desc___compat_syscall_entry_unknown;
 684                 struct lttng_kernel_event_recorder *event_recorder;
 685                 struct lttng_event_recorder_enabler *event_enabler;
 686
 687                 memset(&ev, 0, sizeof(ev));
 688                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN);
 689                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 690                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 691                 ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 692                 ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 693                 event_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev, syscall_event_enabler->chan);
 694                 if (!event_enabler) {
 695                         return -ENOMEM;
 696                 }
 697                 event_recorder = _lttng_kernel_event_recorder_create(event_enabler, desc);
 698                 WARN_ON_ONCE(!event_recorder);
 699                 lttng_event_enabler_destroy(event_enabler);
 700                 if (IS_ERR(event_recorder)) {
 701                         return PTR_ERR(event_recorder);
 702                 }
 703                 hlist_add_head(&event_recorder->priv->parent.u.syscall.node, &syscall_table->compat_unknown_syscall_dispatch);
 704         }
 705
 706         if (hlist_empty(&syscall_table->compat_unknown_syscall_exit_dispatch)) {
 707                 const struct lttng_kernel_event_desc *desc =
 708                         &__event_desc___compat_syscall_exit_unknown;
 709                 struct lttng_kernel_event_recorder *event_recorder;
 710                 struct lttng_event_recorder_enabler *event_enabler;
 711
 712                 memset(&ev, 0, sizeof(ev));
 713                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN);
 714                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 715                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 716                 ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 717                 ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 718                 event_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev, syscall_event_enabler->chan);
 719                 if (!event_enabler) {
 720                         return -ENOMEM;
 721                 }
 722                 event_recorder = _lttng_kernel_event_recorder_create(event_enabler, desc);
 723                 WARN_ON_ONCE(!event_recorder);
 724                 lttng_event_enabler_destroy(event_enabler);
 725                 if (IS_ERR(event_recorder)) {
 726                         return PTR_ERR(event_recorder);
 727                 }
 728                 hlist_add_head(&event_recorder->priv->parent.u.syscall.node, &syscall_table->compat_unknown_syscall_exit_dispatch);
 729         }
 730
 731         if (hlist_empty(&syscall_table->unknown_syscall_exit_dispatch)) {
 732                 const struct lttng_kernel_event_desc *desc =
 733                         &__event_desc___syscall_exit_unknown;
 734                 struct lttng_kernel_event_recorder *event_recorder;
 735                 struct lttng_event_recorder_enabler *event_enabler;
 736
 737                 memset(&ev, 0, sizeof(ev));
 738                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN);
 739                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 740                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 741                 ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 742                 ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 743                 event_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev, syscall_event_enabler->chan);
 744                 if (!event_enabler) {
 745                         return -ENOMEM;
 746                 }
 747                 event_recorder = _lttng_kernel_event_recorder_create(event_enabler, desc);
 748                 WARN_ON_ONCE(!event_recorder);
 749                 lttng_event_enabler_destroy(event_enabler);
 750                 if (IS_ERR(event_recorder)) {
 751                         return PTR_ERR(event_recorder);
 752                 }
 753                 hlist_add_head(&event_recorder->priv->parent.u.syscall.node, &syscall_table->unknown_syscall_exit_dispatch);
 754         }
 755
 756         ret = lttng_create_syscall_event_if_missing(sc_table.table, sc_table.len,
 757                         syscall_table->syscall_dispatch, syscall_event_enabler, SC_TYPE_ENTRY);
 758         if (ret)
 759                 return ret;
 760         ret = lttng_create_syscall_event_if_missing(sc_exit_table.table, sc_exit_table.len,
 761                         syscall_table->syscall_exit_dispatch, syscall_event_enabler, SC_TYPE_EXIT);
 762         if (ret)
 763                 return ret;
 764
 765 #ifdef CONFIG_COMPAT
 766         ret = lttng_create_syscall_event_if_missing(compat_sc_table.table, compat_sc_table.len,
 767                         syscall_table->compat_syscall_dispatch, syscall_event_enabler, SC_TYPE_COMPAT_ENTRY);
 768         if (ret)
 769                 return ret;
 770         ret = lttng_create_syscall_event_if_missing(compat_sc_exit_table.table, compat_sc_exit_table.len,
 771                         syscall_table->compat_syscall_exit_dispatch, syscall_event_enabler, SC_TYPE_COMPAT_EXIT);
 772         if (ret)
 773                 return ret;
 774 #endif
 775
 776         if (!syscall_table->sc_filter) {
 777                 syscall_table->sc_filter = kzalloc(sizeof(struct lttng_syscall_filter),
 778                                 GFP_KERNEL);
 779                 if (!syscall_table->sc_filter)
 780                         return -ENOMEM;
 781         }
 782
 783         if (!syscall_table->sys_enter_registered) {
 784                 ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
 785                                 (void *) syscall_entry_event_probe, syscall_table);
 786                 if (ret)
 787                         return ret;
 788                 syscall_table->sys_enter_registered = 1;
 789         }
 790         /*
 791          * We change the name of sys_exit tracepoint due to namespace
 792          * conflict with sys_exit syscall entry.
 793          */
 794         if (!syscall_table->sys_exit_registered) {
 795                 ret = lttng_wrapper_tracepoint_probe_register("sys_exit",
 796                                 (void *) syscall_exit_event_probe, syscall_table);
 797                 if (ret) {
 798                         WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 799                                 (void *) syscall_entry_event_probe, syscall_table));
 800                         return ret;
 801                 }
 802                 syscall_table->sys_exit_registered = 1;
 803         }
 804         return ret;
 805 }
 806
 807 /*
 808  * Should be called with sessions lock held.
 809  */
 810 int lttng_syscalls_register_event_notifier(
 811                 struct lttng_event_notifier_enabler *event_notifier_enabler)
 812 {
 813         struct lttng_event_notifier_group *group = event_notifier_enabler->group;
 814         struct lttng_kernel_syscall_table *syscall_table = &group->syscall_table;
 815         unsigned int i;
 816         int ret = 0;
 817
 818         wrapper_vmalloc_sync_mappings();
 819
 820         if (!syscall_table->syscall_dispatch) {
 821                 syscall_table->syscall_dispatch = kzalloc(sizeof(struct hlist_head) * sc_table.len, GFP_KERNEL);
 822                 if (!syscall_table->syscall_dispatch)
 823                         return -ENOMEM;
 824
 825                 /* Initialize all list_head */
 826                 for (i = 0; i < sc_table.len; i++)
 827                         INIT_HLIST_HEAD(&syscall_table->syscall_dispatch[i]);
 828
 829                 /* Init the unknown syscall notifier list. */
 830                 INIT_HLIST_HEAD(&syscall_table->unknown_syscall_dispatch);
 831         }
 832
 833         if (!syscall_table->syscall_exit_dispatch) {
 834                 syscall_table->syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * sc_table.len, GFP_KERNEL);
 835                 if (!syscall_table->syscall_exit_dispatch)
 836                         return -ENOMEM;
 837
 838                 /* Initialize all list_head */
 839                 for (i = 0; i < sc_table.len; i++)
 840                         INIT_HLIST_HEAD(&syscall_table->syscall_exit_dispatch[i]);
 841
 842                 /* Init the unknown exit syscall notifier list. */
 843                 INIT_HLIST_HEAD(&syscall_table->unknown_syscall_exit_dispatch);
 844         }
 845
 846 #ifdef CONFIG_COMPAT
 847         if (!syscall_table->compat_syscall_dispatch) {
 848                 syscall_table->compat_syscall_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_table.len, GFP_KERNEL);
 849                 if (!syscall_table->compat_syscall_dispatch)
 850                         return -ENOMEM;
 851
 852                 /* Initialize all list_head */
 853                 for (i = 0; i < compat_sc_table.len; i++)
 854                         INIT_HLIST_HEAD(&syscall_table->compat_syscall_dispatch[i]);
 855
 856                 /* Init the unknown syscall notifier list. */
 857                 INIT_HLIST_HEAD(&syscall_table->compat_unknown_syscall_dispatch);
 858         }
 859
 860         if (!syscall_table->compat_syscall_exit_dispatch) {
 861                 syscall_table->compat_syscall_exit_dispatch =
 862                                 kzalloc(sizeof(struct hlist_head) * compat_sc_exit_table.len,
 863                                         GFP_KERNEL);
 864                 if (!syscall_table->compat_syscall_exit_dispatch)
 865                         return -ENOMEM;
 866
 867                 /* Initialize all list_head */
 868                 for (i = 0; i < compat_sc_exit_table.len; i++)
 869                         INIT_HLIST_HEAD(&syscall_table->compat_syscall_exit_dispatch[i]);
 870
 871                 /* Init the unknown exit syscall notifier list. */
 872                 INIT_HLIST_HEAD(&syscall_table->compat_unknown_syscall_exit_dispatch);
 873         }
 874 #endif
 875
 876         if (!syscall_table->sc_filter) {
 877                 syscall_table->sc_filter = kzalloc(sizeof(struct lttng_syscall_filter),
 878                                 GFP_KERNEL);
 879                 if (!syscall_table->sc_filter)
 880                         return -ENOMEM;
 881         }
 882
 883         if (!syscall_table->sys_enter_registered) {
 884                 ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
 885                                 (void *) syscall_entry_event_probe, syscall_table);
 886                 if (ret)
 887                         return ret;
 888                 syscall_table->sys_enter_registered = 1;
 889         }
 890
 891         if (!syscall_table->sys_exit_registered) {
 892                 ret = lttng_wrapper_tracepoint_probe_register("sys_exit",
 893                                 (void *) syscall_exit_event_probe, syscall_table);
 894                 if (ret) {
 895                         WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 896                                 (void *) syscall_entry_event_probe, syscall_table));
 897                         return ret;
 898                 }
 899                 syscall_table->sys_exit_registered = 1;
 900         }
 901
 902         return ret;
 903 }
 904
 905 static
 906 int create_unknown_event_notifier(
 907                 struct lttng_event_notifier_enabler *event_notifier_enabler,
 908                 enum sc_type type)
 909 {
 910         struct lttng_kernel_event_notifier_private *event_notifier_priv;
 911         struct lttng_kernel_event_notifier *event_notifier;
 912         const struct lttng_kernel_event_desc *desc;
 913         struct lttng_event_notifier_group *group = event_notifier_enabler->group;
 914         struct lttng_kernel_syscall_table *syscall_table = &group->syscall_table;
 915         struct lttng_kernel_abi_event_notifier event_notifier_param;
 916         uint64_t user_token = event_notifier_enabler->parent.user_token;
 917         uint64_t error_counter_index = event_notifier_enabler->error_counter_index;
 918         struct lttng_event_enabler_common *base_enabler = lttng_event_notifier_enabler_as_enabler(
 919                 event_notifier_enabler);
 920         struct hlist_head *unknown_dispatch_list;
 921         int ret = 0;
 922         bool found = false;
 923         enum lttng_kernel_abi_syscall_abi abi;
 924         enum lttng_kernel_abi_syscall_entryexit entryexit;
 925         struct hlist_head *head;
 926
 927         switch (type) {
 928         case SC_TYPE_ENTRY:
 929                 desc = &__event_desc___syscall_entry_unknown;
 930                 unknown_dispatch_list = &syscall_table->unknown_syscall_dispatch;
 931                 entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 932                 abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 933                 break;
 934         case SC_TYPE_EXIT:
 935                 desc = &__event_desc___syscall_exit_unknown;
 936                 unknown_dispatch_list = &syscall_table->unknown_syscall_exit_dispatch;
 937                 entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 938                 abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 939                 break;
 940         case SC_TYPE_COMPAT_ENTRY:
 941                 desc = &__event_desc___compat_syscall_entry_unknown;
 942                 unknown_dispatch_list = &syscall_table->compat_unknown_syscall_dispatch;
 943                 entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 944                 abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 945                 break;
 946         case SC_TYPE_COMPAT_EXIT:
 947                 desc = &__event_desc___compat_syscall_exit_unknown;
 948                 unknown_dispatch_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
 949                 entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 950                 abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 951                 break;
 952         default:
 953                 BUG_ON(1);
 954         }
 955
 956         /*
 957          * Check if already created.
 958          */
 959         head = utils_borrow_hash_table_bucket(group->event_notifiers_ht.table,
 960                 LTTNG_EVENT_NOTIFIER_HT_SIZE, desc->event_name);
 961         lttng_hlist_for_each_entry(event_notifier_priv, head, hlist) {
 962                 if (event_notifier_priv->parent.desc == desc &&
 963                                 event_notifier_priv->parent.user_token == base_enabler->user_token)
 964                         found = true;
 965         }
 966         if (found)
 967                 goto end;
 968
 969         memset(&event_notifier_param, 0, sizeof(event_notifier_param));
 970         strncat(event_notifier_param.event.name, desc->event_name,
 971                 LTTNG_KERNEL_ABI_SYM_NAME_LEN - strlen(event_notifier_param.event.name) - 1);
 972
 973         event_notifier_param.event.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 974
 975         event_notifier_param.event.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 976         event_notifier_param.event.u.syscall.abi = abi;
 977         event_notifier_param.event.u.syscall.entryexit = entryexit;
 978
 979         event_notifier = _lttng_event_notifier_create(desc, user_token,
 980                 error_counter_index, group, &event_notifier_param,
 981                 event_notifier_param.event.instrumentation);
 982         if (IS_ERR(event_notifier)) {
 983                 printk(KERN_INFO "Unable to create unknown notifier %s\n",
 984                         desc->event_name);
 985                 ret = -ENOMEM;
 986                 goto end;
 987         }
 988
 989         hlist_add_head_rcu(&event_notifier->priv->parent.u.syscall.node, unknown_dispatch_list);
 990
 991 end:
 992         return ret;
 993 }
 994
 995 static int create_matching_event_notifiers(
 996                 struct lttng_event_notifier_enabler *event_notifier_enabler,
 997                 const struct trace_syscall_entry *table,
 998                 size_t table_len, enum sc_type type)
 999 {
1000         struct lttng_event_notifier_group *group = event_notifier_enabler->group;
1001         const struct lttng_kernel_event_desc *desc;
1002         uint64_t user_token = event_notifier_enabler->parent.user_token;
1003         uint64_t error_counter_index = event_notifier_enabler->error_counter_index;
1004         unsigned int i;
1005         int ret = 0;
1006
1007         /* iterate over all syscall and create event_notifier that match */
1008         for (i = 0; i < table_len; i++) {
1009                 struct lttng_kernel_event_notifier_private *event_notifier_priv;
1010                 struct lttng_kernel_event_notifier *event_notifier;
1011                 struct lttng_kernel_abi_event_notifier event_notifier_param;
1012                 struct hlist_head *head;
1013                 int found = 0;
1014
1015                 desc = table[i].desc;
1016                 if (!desc) {
1017                         /* Unknown syscall */
1018                         continue;
1019                 }
1020
1021                 if (!lttng_desc_match_enabler(desc,
1022                                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1023                         continue;
1024
1025                 /*
1026                  * Check if already created.
1027                  */
1028                 head = utils_borrow_hash_table_bucket(group->event_notifiers_ht.table,
1029                         LTTNG_EVENT_NOTIFIER_HT_SIZE, desc->event_name);
1030                 lttng_hlist_for_each_entry(event_notifier_priv, head, hlist) {
1031                         if (event_notifier_priv->parent.desc == desc
1032                                 && event_notifier_priv->parent.user_token == event_notifier_enabler->parent.user_token)
1033                                 found = 1;
1034                 }
1035                 if (found)
1036                         continue;
1037
1038                 memset(&event_notifier_param, 0, sizeof(event_notifier_param));
1039                 switch (type) {
1040                 case SC_TYPE_ENTRY:
1041                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
1042                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
1043                         break;
1044                 case SC_TYPE_EXIT:
1045                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
1046                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
1047                         break;
1048                 case SC_TYPE_COMPAT_ENTRY:
1049                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
1050                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
1051                         break;
1052                 case SC_TYPE_COMPAT_EXIT:
1053                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
1054                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
1055                         break;
1056                 }
1057                 strncat(event_notifier_param.event.name, desc->event_name,
1058                         LTTNG_KERNEL_ABI_SYM_NAME_LEN - strlen(event_notifier_param.event.name) - 1);
1059                 event_notifier_param.event.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
1060                 event_notifier_param.event.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
1061
1062                 event_notifier = _lttng_event_notifier_create(desc, user_token,
1063                         error_counter_index, group, &event_notifier_param,
1064                         event_notifier_param.event.instrumentation);
1065                 if (IS_ERR(event_notifier)) {
1066                         printk(KERN_INFO "Unable to create event_notifier %s\n",
1067                                 desc->event_name);
1068                         ret = -ENOMEM;
1069                         goto end;
1070                 }
1071
1072                 event_notifier->priv->parent.u.syscall.syscall_id = i;
1073         }
1074
1075 end:
1076         return ret;
1077
1078 }
1079
1080 int lttng_syscalls_create_matching_event_notifiers(
1081                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1082 {
1083         int ret;
1084         struct lttng_event_enabler_common *base_enabler =
1085                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler);
1086         enum lttng_kernel_abi_syscall_entryexit entryexit =
1087                         base_enabler->event_param.u.syscall.entryexit;
1088
1089         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
1090                 ret = create_matching_event_notifiers(event_notifier_enabler,
1091                         sc_table.table, sc_table.len, SC_TYPE_ENTRY);
1092                 if (ret)
1093                         goto end;
1094
1095                 ret = create_matching_event_notifiers(event_notifier_enabler,
1096                         compat_sc_table.table, compat_sc_table.len,
1097                         SC_TYPE_COMPAT_ENTRY);
1098                 if (ret)
1099                         goto end;
1100
1101                 ret = create_unknown_event_notifier(event_notifier_enabler,
1102                                 SC_TYPE_ENTRY);
1103                 if (ret)
1104                         goto end;
1105
1106                 ret = create_unknown_event_notifier(event_notifier_enabler,
1107                                 SC_TYPE_COMPAT_ENTRY);
1108                 if (ret)
1109                         goto end;
1110         }
1111
1112         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
1113                 ret = create_matching_event_notifiers(event_notifier_enabler,
1114                         sc_exit_table.table, sc_exit_table.len,
1115                         SC_TYPE_EXIT);
1116                 if (ret)
1117                         goto end;
1118
1119                 ret = create_unknown_event_notifier(event_notifier_enabler,
1120                                 SC_TYPE_EXIT);
1121                 if (ret)
1122                         goto end;
1123
1124                 ret = create_matching_event_notifiers(event_notifier_enabler,
1125                         compat_sc_exit_table.table, compat_sc_exit_table.len,
1126                         SC_TYPE_COMPAT_EXIT);
1127                 if (ret)
1128                         goto end;
1129
1130                 ret = create_unknown_event_notifier(event_notifier_enabler,
1131                                 SC_TYPE_COMPAT_EXIT);
1132                 if (ret)
1133                         goto end;
1134         }
1135
1136 end:
1137         return ret;
1138 }
1139
1140 /*
1141  * Unregister the syscall event_notifier probes from the callsites.
1142  */
1143 int lttng_syscalls_unregister_event_notifier_group(
1144                 struct lttng_event_notifier_group *event_notifier_group)
1145 {
1146         struct lttng_kernel_syscall_table *syscall_table = &event_notifier_group->syscall_table;
1147         int ret;
1148
1149         /*
1150          * Only register the event_notifier probe on the `sys_enter` callsite for now.
1151          * At the moment, we don't think it's desirable to have one fired
1152          * event_notifier for the entry and one for the exit of a syscall.
1153          */
1154         if (syscall_table->sys_enter_registered) {
1155                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
1156                                 (void *) syscall_entry_event_probe, syscall_table);
1157                 if (ret)
1158                         return ret;
1159                 syscall_table->sys_enter_registered = 0;
1160         }
1161         if (syscall_table->sys_exit_registered) {
1162                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
1163                                 (void *) syscall_exit_event_probe, syscall_table);
1164                 if (ret)
1165                         return ret;
1166                 syscall_table->sys_enter_registered = 0;
1167         }
1168
1169         kfree(syscall_table->syscall_dispatch);
1170         kfree(syscall_table->syscall_exit_dispatch);
1171 #ifdef CONFIG_COMPAT
1172         kfree(syscall_table->compat_syscall_dispatch);
1173         kfree(syscall_table->compat_syscall_exit_dispatch);
1174 #endif
1175         return 0;
1176 }
1177
1178 int lttng_syscalls_unregister_channel(struct lttng_kernel_channel_buffer *chan)
1179 {
1180         struct lttng_kernel_syscall_table *syscall_table = &chan->priv->parent.syscall_table;
1181         int ret;
1182
1183         if (!syscall_table->syscall_dispatch)
1184                 return 0;
1185         if (syscall_table->sys_enter_registered) {
1186                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
1187                                 (void *) syscall_entry_event_probe, syscall_table);
1188                 if (ret)
1189                         return ret;
1190                 syscall_table->sys_enter_registered = 0;
1191         }
1192         if (syscall_table->sys_exit_registered) {
1193                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
1194                                 (void *) syscall_exit_event_probe, syscall_table);
1195                 if (ret)
1196                         return ret;
1197                 syscall_table->sys_exit_registered = 0;
1198         }
1199         return 0;
1200 }
1201
1202 int lttng_syscalls_destroy_event(struct lttng_kernel_channel_buffer *chan)
1203 {
1204         struct lttng_kernel_syscall_table *syscall_table = &chan->priv->parent.syscall_table;
1205
1206         kfree(syscall_table->syscall_dispatch);
1207         kfree(syscall_table->syscall_exit_dispatch);
1208 #ifdef CONFIG_COMPAT
1209         kfree(syscall_table->compat_syscall_dispatch);
1210         kfree(syscall_table->compat_syscall_exit_dispatch);
1211 #endif
1212         kfree(syscall_table->sc_filter);
1213         return 0;
1214 }
1215
1216 static
1217 int get_syscall_nr(const char *syscall_name)
1218 {
1219         int syscall_nr = -1;
1220         int i;
1221
1222         for (i = 0; i < sc_table.len; i++) {
1223                 const struct trace_syscall_entry *entry;
1224                 const char *it_name;
1225
1226                 entry = &sc_table.table[i];
1227                 if (!entry->desc)
1228                         continue;
1229                 it_name = entry->desc->event_name;
1230                 it_name += strlen(SYSCALL_ENTRY_STR);
1231                 if (!strcmp(syscall_name, it_name)) {
1232                         syscall_nr = i;
1233                         break;
1234                 }
1235         }
1236         return syscall_nr;
1237 }
1238
1239 static
1240 int get_compat_syscall_nr(const char *syscall_name)
1241 {
1242         int syscall_nr = -1;
1243         int i;
1244
1245         for (i = 0; i < compat_sc_table.len; i++) {
1246                 const struct trace_syscall_entry *entry;
1247                 const char *it_name;
1248
1249                 entry = &compat_sc_table.table[i];
1250                 if (!entry->desc)
1251                         continue;
1252                 it_name = entry->desc->event_name;
1253                 it_name += strlen(COMPAT_SYSCALL_ENTRY_STR);
1254                 if (!strcmp(syscall_name, it_name)) {
1255                         syscall_nr = i;
1256                         break;
1257                 }
1258         }
1259         return syscall_nr;
1260 }
1261
1262 static
1263 uint32_t get_sc_tables_len(void)
1264 {
1265         return sc_table.len + compat_sc_table.len;
1266 }
1267
1268 static
1269 const char *get_syscall_name(const char *desc_name,
1270                 enum lttng_syscall_abi abi,
1271                 enum lttng_syscall_entryexit entryexit)
1272 {
1273         size_t prefix_len = 0;
1274
1275
1276         switch (entryexit) {
1277         case LTTNG_SYSCALL_ENTRY:
1278                 switch (abi) {
1279                 case LTTNG_SYSCALL_ABI_NATIVE:
1280                         prefix_len = strlen(SYSCALL_ENTRY_STR);
1281                         break;
1282                 case LTTNG_SYSCALL_ABI_COMPAT:
1283                         prefix_len = strlen(COMPAT_SYSCALL_ENTRY_STR);
1284                         break;
1285                 }
1286                 break;
1287         case LTTNG_SYSCALL_EXIT:
1288                 switch (abi) {
1289                 case LTTNG_SYSCALL_ABI_NATIVE:
1290                         prefix_len = strlen(SYSCALL_EXIT_STR);
1291                         break;
1292                 case LTTNG_SYSCALL_ABI_COMPAT:
1293                         prefix_len = strlen(COMPAT_SYSCALL_EXIT_STR);
1294                         break;
1295                 }
1296                 break;
1297         }
1298         WARN_ON_ONCE(prefix_len == 0);
1299         return desc_name + prefix_len;
1300 }
1301
1302 static
1303 int lttng_syscall_filter_enable(
1304                 struct lttng_syscall_filter *filter,
1305                 const char *desc_name, enum lttng_syscall_abi abi,
1306                 enum lttng_syscall_entryexit entryexit)
1307 {
1308         const char *syscall_name;
1309         unsigned long *bitmap;
1310         int syscall_nr;
1311
1312         syscall_name = get_syscall_name(desc_name, abi, entryexit);
1313
1314         switch (abi) {
1315         case LTTNG_SYSCALL_ABI_NATIVE:
1316                 syscall_nr = get_syscall_nr(syscall_name);
1317                 break;
1318         case LTTNG_SYSCALL_ABI_COMPAT:
1319                 syscall_nr = get_compat_syscall_nr(syscall_name);
1320                 break;
1321         default:
1322                 return -EINVAL;
1323         }
1324         if (syscall_nr < 0)
1325                 return -ENOENT;
1326
1327         switch (entryexit) {
1328         case LTTNG_SYSCALL_ENTRY:
1329                 switch (abi) {
1330                 case LTTNG_SYSCALL_ABI_NATIVE:
1331                         bitmap = filter->sc_entry;
1332                         break;
1333                 case LTTNG_SYSCALL_ABI_COMPAT:
1334                         bitmap = filter->sc_compat_entry;
1335                         break;
1336                 default:
1337                         return -EINVAL;
1338                 }
1339                 break;
1340         case LTTNG_SYSCALL_EXIT:
1341                 switch (abi) {
1342                 case LTTNG_SYSCALL_ABI_NATIVE:
1343                         bitmap = filter->sc_exit;
1344                         break;
1345                 case LTTNG_SYSCALL_ABI_COMPAT:
1346                         bitmap = filter->sc_compat_exit;
1347                         break;
1348                 default:
1349                         return -EINVAL;
1350                 }
1351                 break;
1352         default:
1353                 return -EINVAL;
1354         }
1355         if (test_bit(syscall_nr, bitmap))
1356                 return -EEXIST;
1357         bitmap_set(bitmap, syscall_nr, 1);
1358         return 0;
1359 }
1360
1361 int lttng_syscall_filter_enable_event_notifier(
1362                 struct lttng_kernel_event_notifier *event_notifier)
1363 {
1364         struct lttng_event_notifier_group *group = event_notifier->priv->group;
1365         struct lttng_kernel_syscall_table *syscall_table = &group->syscall_table;
1366         unsigned int syscall_id = event_notifier->priv->parent.u.syscall.syscall_id;
1367         struct hlist_head *dispatch_list;
1368         int ret = 0;
1369
1370         WARN_ON_ONCE(event_notifier->priv->parent.instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
1371
1372         ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
1373                 event_notifier->priv->parent.desc->event_name,
1374                 event_notifier->priv->parent.u.syscall.abi,
1375                 event_notifier->priv->parent.u.syscall.entryexit);
1376         if (ret) {
1377                 goto end;
1378         }
1379
1380         switch (event_notifier->priv->parent.u.syscall.entryexit) {
1381         case LTTNG_SYSCALL_ENTRY:
1382                 switch (event_notifier->priv->parent.u.syscall.abi) {
1383                 case LTTNG_SYSCALL_ABI_NATIVE:
1384                         dispatch_list = &syscall_table->syscall_dispatch[syscall_id];
1385                         break;
1386                 case LTTNG_SYSCALL_ABI_COMPAT:
1387                         dispatch_list = &syscall_table->compat_syscall_dispatch[syscall_id];
1388                         break;
1389                 default:
1390                         ret = -EINVAL;
1391                         goto end;
1392                 }
1393                 break;
1394         case LTTNG_SYSCALL_EXIT:
1395                 switch (event_notifier->priv->parent.u.syscall.abi) {
1396                 case LTTNG_SYSCALL_ABI_NATIVE:
1397                         dispatch_list = &syscall_table->syscall_exit_dispatch[syscall_id];
1398                         break;
1399                 case LTTNG_SYSCALL_ABI_COMPAT:
1400                         dispatch_list = &syscall_table->compat_syscall_exit_dispatch[syscall_id];
1401                         break;
1402                 default:
1403                         ret = -EINVAL;
1404                         goto end;
1405                 }
1406                 break;
1407         default:
1408                 ret = -EINVAL;
1409                 goto end;
1410         }
1411
1412         hlist_add_head_rcu(&event_notifier->priv->parent.u.syscall.node, dispatch_list);
1413
1414 end:
1415         return ret ;
1416 }
1417
1418 int lttng_syscall_filter_enable_event(
1419                 struct lttng_kernel_channel_buffer *channel,
1420                 struct lttng_kernel_event_recorder *event_recorder)
1421 {
1422         struct lttng_kernel_syscall_table *syscall_table = &channel->priv->parent.syscall_table;
1423
1424         WARN_ON_ONCE(event_recorder->priv->parent.instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
1425
1426         return lttng_syscall_filter_enable(syscall_table->sc_filter,
1427                 event_recorder->priv->parent.desc->event_name,
1428                 event_recorder->priv->parent.u.syscall.abi,
1429                 event_recorder->priv->parent.u.syscall.entryexit);
1430 }
1431
1432 static
1433 int lttng_syscall_filter_disable(
1434                 struct lttng_syscall_filter *filter,
1435                 const char *desc_name, enum lttng_syscall_abi abi,
1436                 enum lttng_syscall_entryexit entryexit)
1437 {
1438         const char *syscall_name;
1439         unsigned long *bitmap;
1440         int syscall_nr;
1441
1442         syscall_name = get_syscall_name(desc_name, abi, entryexit);
1443
1444         switch (abi) {
1445         case LTTNG_SYSCALL_ABI_NATIVE:
1446                 syscall_nr = get_syscall_nr(syscall_name);
1447                 break;
1448         case LTTNG_SYSCALL_ABI_COMPAT:
1449                 syscall_nr = get_compat_syscall_nr(syscall_name);
1450                 break;
1451         default:
1452                 return -EINVAL;
1453         }
1454         if (syscall_nr < 0)
1455                 return -ENOENT;
1456
1457         switch (entryexit) {
1458         case LTTNG_SYSCALL_ENTRY:
1459                 switch (abi) {
1460                 case LTTNG_SYSCALL_ABI_NATIVE:
1461                         bitmap = filter->sc_entry;
1462                         break;
1463                 case LTTNG_SYSCALL_ABI_COMPAT:
1464                         bitmap = filter->sc_compat_entry;
1465                         break;
1466                 default:
1467                         return -EINVAL;
1468                 }
1469                 break;
1470         case LTTNG_SYSCALL_EXIT:
1471                 switch (abi) {
1472                 case LTTNG_SYSCALL_ABI_NATIVE:
1473                         bitmap = filter->sc_exit;
1474                         break;
1475                 case LTTNG_SYSCALL_ABI_COMPAT:
1476                         bitmap = filter->sc_compat_exit;
1477                         break;
1478                 default:
1479                         return -EINVAL;
1480                 }
1481                 break;
1482         default:
1483                 return -EINVAL;
1484         }
1485         if (!test_bit(syscall_nr, bitmap))
1486                 return -EEXIST;
1487         bitmap_clear(bitmap, syscall_nr, 1);
1488
1489         return 0;
1490 }
1491
1492 int lttng_syscall_filter_disable_event_notifier(
1493                 struct lttng_kernel_event_notifier *event_notifier)
1494 {
1495         struct lttng_event_notifier_group *group = event_notifier->priv->group;
1496         struct lttng_kernel_syscall_table *syscall_table = &group->syscall_table;
1497         int ret;
1498
1499         WARN_ON_ONCE(event_notifier->priv->parent.instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
1500
1501         ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
1502                 event_notifier->priv->parent.desc->event_name,
1503                 event_notifier->priv->parent.u.syscall.abi,
1504                 event_notifier->priv->parent.u.syscall.entryexit);
1505         WARN_ON_ONCE(ret != 0);
1506
1507         hlist_del_rcu(&event_notifier->priv->parent.u.syscall.node);
1508         return 0;
1509 }
1510
1511 int lttng_syscall_filter_disable_event(
1512                 struct lttng_kernel_channel_buffer *channel,
1513                 struct lttng_kernel_event_recorder *event_recorder)
1514 {
1515         struct lttng_kernel_syscall_table *syscall_table = &channel->priv->parent.syscall_table;
1516
1517         return lttng_syscall_filter_disable(syscall_table->sc_filter,
1518                 event_recorder->priv->parent.desc->event_name,
1519                 event_recorder->priv->parent.u.syscall.abi,
1520                 event_recorder->priv->parent.u.syscall.entryexit);
1521 }
1522
1523 static
1524 const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
1525 {
1526         const struct trace_syscall_entry *entry;
1527         int iter = 0;
1528
1529         for (entry = sc_table.table;
1530                         entry < sc_table.table + sc_table.len;
1531                          entry++) {
1532                 if (iter++ >= *pos)
1533                         return entry;
1534         }
1535         for (entry = compat_sc_table.table;
1536                         entry < compat_sc_table.table + compat_sc_table.len;
1537                          entry++) {
1538                 if (iter++ >= *pos)
1539                         return entry;
1540         }
1541         /* End of list */
1542         return NULL;
1543 }
1544
1545 static
1546 void *syscall_list_start(struct seq_file *m, loff_t *pos)
1547 {
1548         return (void *) syscall_list_get_entry(pos);
1549 }
1550
1551 static
1552 void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
1553 {
1554         (*ppos)++;
1555         return (void *) syscall_list_get_entry(ppos);
1556 }
1557
1558 static
1559 void syscall_list_stop(struct seq_file *m, void *p)
1560 {
1561 }
1562
1563 static
1564 int get_sc_table(const struct trace_syscall_entry *entry,
1565                 const struct trace_syscall_entry **table,
1566                 unsigned int *bitness)
1567 {
1568         if (entry >= sc_table.table && entry < sc_table.table + sc_table.len) {
1569                 if (bitness)
1570                         *bitness = BITS_PER_LONG;
1571                 if (table)
1572                         *table = sc_table.table;
1573                 return 0;
1574         }
1575         if (!(entry >= compat_sc_table.table
1576                         && entry < compat_sc_table.table + compat_sc_table.len)) {
1577                 return -EINVAL;
1578         }
1579         if (bitness)
1580                 *bitness = 32;
1581         if (table)
1582                 *table = compat_sc_table.table;
1583         return 0;
1584 }
1585
1586 static
1587 int syscall_list_show(struct seq_file *m, void *p)
1588 {
1589         const struct trace_syscall_entry *table, *entry = p;
1590         unsigned int bitness;
1591         unsigned long index;
1592         int ret;
1593         const char *name;
1594
1595         ret = get_sc_table(entry, &table, &bitness);
1596         if (ret)
1597                 return ret;
1598         if (!entry->desc)
1599                 return 0;
1600         if (table == sc_table.table) {
1601                 index = entry - table;
1602                 name = &entry->desc->event_name[strlen(SYSCALL_ENTRY_STR)];
1603         } else {
1604                 index = (entry - table) + sc_table.len;
1605                 name = &entry->desc->event_name[strlen(COMPAT_SYSCALL_ENTRY_STR)];
1606         }
1607         seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
1608                 index, name, bitness);
1609         return 0;
1610 }
1611
1612 static
1613 const struct seq_operations lttng_syscall_list_seq_ops = {
1614         .start = syscall_list_start,
1615         .next = syscall_list_next,
1616         .stop = syscall_list_stop,
1617         .show = syscall_list_show,
1618 };
1619
1620 static
1621 int lttng_syscall_list_open(struct inode *inode, struct file *file)
1622 {
1623         return seq_open(file, &lttng_syscall_list_seq_ops);
1624 }
1625
1626 const struct file_operations lttng_syscall_list_fops = {
1627         .owner = THIS_MODULE,
1628         .open = lttng_syscall_list_open,
1629         .read = seq_read,
1630         .llseek = seq_lseek,
1631         .release = seq_release,
1632 };
1633
1634 /*
1635  * A syscall is enabled if it is traced for either entry or exit.
1636  */
1637 long lttng_channel_syscall_mask(struct lttng_kernel_channel_buffer *channel,
1638                 struct lttng_kernel_abi_syscall_mask __user *usyscall_mask)
1639 {
1640         struct lttng_kernel_syscall_table *syscall_table = &channel->priv->parent.syscall_table;
1641         uint32_t len, sc_tables_len, bitmask_len;
1642         int ret = 0, bit;
1643         char *tmp_mask;
1644         struct lttng_syscall_filter *filter;
1645
1646         ret = get_user(len, &usyscall_mask->len);
1647         if (ret)
1648                 return ret;
1649         sc_tables_len = get_sc_tables_len();
1650         bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
1651         if (len < sc_tables_len) {
1652                 return put_user(sc_tables_len, &usyscall_mask->len);
1653         }
1654         /* Array is large enough, we can copy array to user-space. */
1655         tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
1656         if (!tmp_mask)
1657                 return -ENOMEM;
1658         filter = syscall_table->sc_filter;
1659
1660         for (bit = 0; bit < sc_table.len; bit++) {
1661                 char state;
1662
1663                 if (syscall_table->syscall_dispatch) {
1664                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1665                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1666                                 state = test_bit(bit, filter->sc_entry)
1667                                         || test_bit(bit, filter->sc_exit);
1668                         else
1669                                 state = 1;
1670                 } else {
1671                         state = 0;
1672                 }
1673                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1674         }
1675         for (; bit < sc_tables_len; bit++) {
1676                 char state;
1677
1678                 if (syscall_table->compat_syscall_dispatch) {
1679                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1680                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1681                                 state = test_bit(bit - sc_table.len,
1682                                                 filter->sc_compat_entry)
1683                                         || test_bit(bit - sc_table.len,
1684                                                 filter->sc_compat_exit);
1685                         else
1686                                 state = 1;
1687                 } else {
1688                         state = 0;
1689                 }
1690                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1691         }
1692         if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
1693                 ret = -EFAULT;
1694         kfree(tmp_mask);
1695         return ret;
1696 }
1697
1698 int lttng_abi_syscall_list(void)
1699 {
1700         struct file *syscall_list_file;
1701         int file_fd, ret;
1702
1703         file_fd = lttng_get_unused_fd();
1704         if (file_fd < 0) {
1705                 ret = file_fd;
1706                 goto fd_error;
1707         }
1708
1709         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
1710                                           &lttng_syscall_list_fops,
1711                                           NULL, O_RDWR);
1712         if (IS_ERR(syscall_list_file)) {
1713                 ret = PTR_ERR(syscall_list_file);
1714                 goto file_error;
1715         }
1716         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
1717         if (ret < 0)
1718                 goto open_error;
1719         fd_install(file_fd, syscall_list_file);
1720         return file_fd;
1721
1722 open_error:
1723         fput(syscall_list_file);
1724 file_error:
1725         put_unused_fd(file_fd);
1726 fd_error:
1727         return ret;
1728 }