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 static
 528 void lttng_syscall_event_enabler_create_event(struct lttng_event_enabler_common *syscall_event_enabler,
 529                 const struct lttng_kernel_event_desc *desc, struct hlist_head *dispatch_table,
 530                 enum sc_type type, unsigned int syscall_nr)
 531 {
 532         struct lttng_kernel_event_common *event;
 533
 534         switch (syscall_event_enabler->enabler_type) {
 535         case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
 536         {
 537                 struct lttng_event_recorder_enabler *syscall_event_recorder_enabler =
 538                         container_of(syscall_event_enabler, struct lttng_event_recorder_enabler, parent);
 539                 struct lttng_event_recorder_enabler *event_recorder_enabler;
 540                 struct lttng_kernel_abi_event ev;
 541
 542                 /* We need to create an event for this syscall/enabler. */
 543                 memset(&ev, 0, sizeof(ev));
 544                 switch (type) {
 545                 case SC_TYPE_ENTRY:
 546                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 547                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 548                         break;
 549                 case SC_TYPE_EXIT:
 550                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 551                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 552                         break;
 553                 case SC_TYPE_COMPAT_ENTRY:
 554                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 555                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 556                         break;
 557                 case SC_TYPE_COMPAT_EXIT:
 558                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 559                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 560                         break;
 561                 }
 562                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1);
 563                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 564                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 565                 event_recorder_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev,
 566                                 syscall_event_recorder_enabler->chan);
 567                 WARN_ON_ONCE(!event_recorder_enabler);
 568                 if (!event_recorder_enabler)
 569                         return;
 570                 event = _lttng_kernel_event_create(&event_recorder_enabler->parent, desc);
 571                 WARN_ON_ONCE(IS_ERR(event));
 572                 lttng_event_enabler_destroy(&event_recorder_enabler->parent);
 573                 if (IS_ERR(event)) {
 574                         printk(KERN_INFO "Unable to create event recorder %s\n", desc->event_name);
 575                         return;
 576                 }
 577                 event->priv->u.syscall.syscall_id = syscall_nr;
 578                 if (dispatch_table)
 579                         hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_table);
 580                 break;
 581         }
 582         case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
 583         {
 584                 struct lttng_event_notifier_enabler *syscall_event_notifier_enabler =
 585                         container_of(syscall_event_enabler, struct lttng_event_notifier_enabler, parent);
 586                 struct lttng_event_notifier_enabler *event_notifier_enabler;
 587                 struct lttng_kernel_abi_event_notifier event_notifier_param;
 588                 uint64_t user_token = syscall_event_enabler->user_token;
 589                 uint64_t error_counter_index = syscall_event_notifier_enabler->error_counter_index;
 590
 591                 memset(&event_notifier_param, 0, sizeof(event_notifier_param));
 592                 switch (type) {
 593                 case SC_TYPE_ENTRY:
 594                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 595                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 596                         break;
 597                 case SC_TYPE_EXIT:
 598                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 599                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 600                         break;
 601                 case SC_TYPE_COMPAT_ENTRY:
 602                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 603                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 604                         break;
 605                 case SC_TYPE_COMPAT_EXIT:
 606                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 607                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 608                         break;
 609                 }
 610                 strncat(event_notifier_param.event.name, desc->event_name,
 611                         LTTNG_KERNEL_ABI_SYM_NAME_LEN - strlen(event_notifier_param.event.name) - 1);
 612                 event_notifier_param.event.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 613                 event_notifier_param.event.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 614                 event_notifier_param.event.token = user_token;
 615                 event_notifier_param.error_counter_index = error_counter_index;
 616
 617                 event_notifier_enabler = lttng_event_notifier_enabler_create(LTTNG_ENABLER_FORMAT_NAME,
 618                                 &event_notifier_param, syscall_event_notifier_enabler->group);
 619                 WARN_ON_ONCE(!event_notifier_enabler);
 620                 event = _lttng_kernel_event_create(&event_notifier_enabler->parent, desc);
 621                 WARN_ON_ONCE(IS_ERR(event));
 622                 lttng_event_enabler_destroy(&event_notifier_enabler->parent);
 623                 if (IS_ERR(event)) {
 624                         printk(KERN_INFO "Unable to create event notifier %s\n", desc->event_name);
 625                         return;
 626                 }
 627                 event->priv->u.syscall.syscall_id = syscall_nr;
 628                 if (dispatch_table)
 629                         hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_table);
 630                 break;
 631         }
 632         default:
 633                 break;
 634         }
 635 }
 636
 637 static
 638 void lttng_syscall_event_enabler_create_matching_syscall_table_events(struct lttng_event_enabler_common *syscall_event_enabler_common,
 639                 const struct trace_syscall_entry *table, size_t table_len, enum sc_type type)
 640 {
 641         struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(syscall_event_enabler_common);
 642         const struct lttng_kernel_event_desc *desc;
 643         unsigned int i;
 644
 645         if (!IS_ENABLED(CONFIG_COMPAT) && (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT))
 646                 return;
 647
 648         /* iterate over all syscall and create event that match */
 649         for (i = 0; i < table_len; i++) {
 650                 struct lttng_kernel_event_common_private *event_priv;
 651                 struct hlist_head *head;
 652                 int found = 0;
 653
 654                 desc = table[i].desc;
 655                 if (!desc) {
 656                         /* Unknown syscall */
 657                         continue;
 658                 }
 659
 660                 if (!lttng_desc_match_enabler(desc, syscall_event_enabler_common))
 661                         continue;
 662
 663                 /*
 664                  * Check if already created.
 665                  */
 666                 head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 667                 lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
 668                         if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub))
 669                                 found = 1;
 670                 }
 671                 if (found)
 672                         continue;
 673
 674                 lttng_syscall_event_enabler_create_event(syscall_event_enabler_common, desc, NULL, type, i);
 675         }
 676 }
 677
 678 static
 679 bool lttng_syscall_event_enabler_is_wildcard_all(struct lttng_event_enabler_common *event_enabler)
 680 {
 681         if (event_enabler->event_param.instrumentation != LTTNG_KERNEL_ABI_SYSCALL)
 682                 return false;
 683         if (event_enabler->event_param.u.syscall.abi != LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL)
 684                 return false;
 685         if (event_enabler->event_param.u.syscall.match != LTTNG_KERNEL_ABI_SYSCALL_MATCH_NAME)
 686                 return false;
 687         if (strcmp(event_enabler->event_param.name, "*"))
 688                 return false;
 689         return true;
 690 }
 691
 692 static
 693 void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabler, enum sc_type type)
 694 {
 695         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(event_enabler);
 696         struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(event_enabler);
 697         struct lttng_kernel_event_common_private *event_priv;
 698         const struct lttng_kernel_event_desc *desc;
 699         struct hlist_head *unknown_dispatch_list;
 700         bool found = false;
 701         struct hlist_head *head;
 702
 703         if (!IS_ENABLED(CONFIG_COMPAT) && (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT))
 704                 return;
 705
 706         /*
 707          * Considering that currently system calls can only be enabled on a per
 708          * name basis (or wildcard based on a name), unknown syscall events are
 709          * only used when matching *all* system calls, because this is the only
 710          * case which can be associated with an unknown system call.
 711          *
 712          * When enabling system call on a per system call number basis will be
 713          * supported, this will need to be revisited.
 714          */
 715         if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
 716                 return;
 717
 718         switch (type) {
 719         case SC_TYPE_ENTRY:
 720                 desc = &__event_desc___syscall_entry_unknown;
 721                 unknown_dispatch_list = &syscall_table->unknown_syscall_dispatch;
 722                 break;
 723         case SC_TYPE_EXIT:
 724                 desc = &__event_desc___syscall_exit_unknown;
 725                 unknown_dispatch_list = &syscall_table->unknown_syscall_exit_dispatch;
 726                 break;
 727         case SC_TYPE_COMPAT_ENTRY:
 728                 desc = &__event_desc___compat_syscall_entry_unknown;
 729                 unknown_dispatch_list = &syscall_table->compat_unknown_syscall_dispatch;
 730                 break;
 731         case SC_TYPE_COMPAT_EXIT:
 732                 desc = &__event_desc___compat_syscall_exit_unknown;
 733                 unknown_dispatch_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
 734                 break;
 735         default:
 736                 WARN_ON_ONCE(1);
 737         }
 738
 739         /*
 740          * Check if already created.
 741          */
 742         head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 743         lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
 744                 if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub))
 745                         found = true;
 746         }
 747         if (!found)
 748                 lttng_syscall_event_enabler_create_event(event_enabler, desc, unknown_dispatch_list, type, -1U);
 749 }
 750
 751 static
 752 void lttng_syscall_event_enabler_create_matching_events(struct lttng_event_enabler_common *event_enabler)
 753 {
 754         enum lttng_kernel_abi_syscall_entryexit entryexit = event_enabler->event_param.u.syscall.entryexit;
 755
 756         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
 757                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 758                         sc_table.table, sc_table.len, SC_TYPE_ENTRY);
 759                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 760                         compat_sc_table.table, compat_sc_table.len, SC_TYPE_COMPAT_ENTRY);
 761                 create_unknown_syscall_event(event_enabler, SC_TYPE_ENTRY);
 762                 create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_ENTRY);
 763         }
 764
 765         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
 766                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 767                         sc_exit_table.table, sc_exit_table.len, SC_TYPE_EXIT);
 768                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 769                         compat_sc_exit_table.table, compat_sc_exit_table.len, SC_TYPE_COMPAT_EXIT);
 770                 create_unknown_syscall_event(event_enabler, SC_TYPE_EXIT);
 771                 create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_EXIT);
 772         }
 773 }
 774
 775 /*
 776  * Should be called with sessions lock held.
 777  */
 778 int lttng_event_enabler_create_syscall_events_if_missing(struct lttng_event_enabler_common *syscall_event_enabler)
 779 {
 780         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(syscall_event_enabler);
 781         int ret;
 782
 783         if (!syscall_table->syscall_dispatch) {
 784                 /* create syscall table mapping syscall to events */
 785                 syscall_table->syscall_dispatch = kzalloc(sizeof(struct hlist_head) * sc_table.len, GFP_KERNEL);
 786                 if (!syscall_table->syscall_dispatch)
 787                         return -ENOMEM;
 788         }
 789         if (!syscall_table->syscall_exit_dispatch) {
 790                 /* create syscall table mapping syscall to events */
 791                 syscall_table->syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * sc_exit_table.len, GFP_KERNEL);
 792                 if (!syscall_table->syscall_exit_dispatch)
 793                         return -ENOMEM;
 794         }
 795
 796 #ifdef CONFIG_COMPAT
 797         if (!syscall_table->compat_syscall_dispatch) {
 798                 /* create syscall table mapping compat syscall to events */
 799                 syscall_table->compat_syscall_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_table.len, GFP_KERNEL);
 800                 if (!syscall_table->compat_syscall_dispatch)
 801                         return -ENOMEM;
 802         }
 803
 804         if (!syscall_table->compat_syscall_exit_dispatch) {
 805                 /* create syscall table mapping compat syscall to events */
 806                 syscall_table->compat_syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_exit_table.len, GFP_KERNEL);
 807                 if (!syscall_table->compat_syscall_exit_dispatch)
 808                         return -ENOMEM;
 809         }
 810 #endif
 811         if (!syscall_table->sc_filter) {
 812                 syscall_table->sc_filter = kzalloc(sizeof(struct lttng_syscall_filter),
 813                                 GFP_KERNEL);
 814                 if (!syscall_table->sc_filter)
 815                         return -ENOMEM;
 816         }
 817
 818         if (!syscall_table->sys_enter_registered) {
 819                 ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
 820                                 (void *) syscall_entry_event_probe, syscall_table);
 821                 if (ret)
 822                         return ret;
 823                 syscall_table->sys_enter_registered = 1;
 824         }
 825         if (!syscall_table->sys_exit_registered) {
 826                 ret = lttng_wrapper_tracepoint_probe_register("sys_exit",
 827                                 (void *) syscall_exit_event_probe, syscall_table);
 828                 if (ret) {
 829                         WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 830                                 (void *) syscall_entry_event_probe, syscall_table));
 831                         return ret;
 832                 }
 833                 syscall_table->sys_exit_registered = 1;
 834         }
 835
 836         lttng_syscall_event_enabler_create_matching_events(syscall_event_enabler);
 837
 838         return ret;
 839 }
 840
 841 int lttng_syscalls_unregister_syscall_table(struct lttng_kernel_syscall_table *syscall_table)
 842 {
 843         int ret;
 844
 845         if (!syscall_table->syscall_dispatch)
 846                 return 0;
 847         if (syscall_table->sys_enter_registered) {
 848                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 849                                 (void *) syscall_entry_event_probe, syscall_table);
 850                 if (ret)
 851                         return ret;
 852                 syscall_table->sys_enter_registered = 0;
 853         }
 854         if (syscall_table->sys_exit_registered) {
 855                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
 856                                 (void *) syscall_exit_event_probe, syscall_table);
 857                 if (ret)
 858                         return ret;
 859                 syscall_table->sys_exit_registered = 0;
 860         }
 861         return 0;
 862 }
 863
 864 int lttng_syscalls_destroy_syscall_table(struct lttng_kernel_syscall_table *syscall_table)
 865 {
 866         kfree(syscall_table->syscall_dispatch);
 867         kfree(syscall_table->syscall_exit_dispatch);
 868 #ifdef CONFIG_COMPAT
 869         kfree(syscall_table->compat_syscall_dispatch);
 870         kfree(syscall_table->compat_syscall_exit_dispatch);
 871 #endif
 872         kfree(syscall_table->sc_filter);
 873         return 0;
 874 }
 875
 876 static
 877 int get_syscall_nr(const char *syscall_name)
 878 {
 879         int syscall_nr = -1;
 880         int i;
 881
 882         for (i = 0; i < sc_table.len; i++) {
 883                 const struct trace_syscall_entry *entry;
 884                 const char *it_name;
 885
 886                 entry = &sc_table.table[i];
 887                 if (!entry->desc)
 888                         continue;
 889                 it_name = entry->desc->event_name;
 890                 it_name += strlen(SYSCALL_ENTRY_STR);
 891                 if (!strcmp(syscall_name, it_name)) {
 892                         syscall_nr = i;
 893                         break;
 894                 }
 895         }
 896         return syscall_nr;
 897 }
 898
 899 static
 900 int get_compat_syscall_nr(const char *syscall_name)
 901 {
 902         int syscall_nr = -1;
 903         int i;
 904
 905         for (i = 0; i < compat_sc_table.len; i++) {
 906                 const struct trace_syscall_entry *entry;
 907                 const char *it_name;
 908
 909                 entry = &compat_sc_table.table[i];
 910                 if (!entry->desc)
 911                         continue;
 912                 it_name = entry->desc->event_name;
 913                 it_name += strlen(COMPAT_SYSCALL_ENTRY_STR);
 914                 if (!strcmp(syscall_name, it_name)) {
 915                         syscall_nr = i;
 916                         break;
 917                 }
 918         }
 919         return syscall_nr;
 920 }
 921
 922 static
 923 uint32_t get_sc_tables_len(void)
 924 {
 925         return sc_table.len + compat_sc_table.len;
 926 }
 927
 928 static
 929 const char *get_syscall_name(const char *desc_name,
 930                 enum lttng_syscall_abi abi,
 931                 enum lttng_syscall_entryexit entryexit)
 932 {
 933         size_t prefix_len = 0;
 934
 935
 936         switch (entryexit) {
 937         case LTTNG_SYSCALL_ENTRY:
 938                 switch (abi) {
 939                 case LTTNG_SYSCALL_ABI_NATIVE:
 940                         prefix_len = strlen(SYSCALL_ENTRY_STR);
 941                         break;
 942                 case LTTNG_SYSCALL_ABI_COMPAT:
 943                         prefix_len = strlen(COMPAT_SYSCALL_ENTRY_STR);
 944                         break;
 945                 }
 946                 break;
 947         case LTTNG_SYSCALL_EXIT:
 948                 switch (abi) {
 949                 case LTTNG_SYSCALL_ABI_NATIVE:
 950                         prefix_len = strlen(SYSCALL_EXIT_STR);
 951                         break;
 952                 case LTTNG_SYSCALL_ABI_COMPAT:
 953                         prefix_len = strlen(COMPAT_SYSCALL_EXIT_STR);
 954                         break;
 955                 }
 956                 break;
 957         }
 958         WARN_ON_ONCE(prefix_len == 0);
 959         return desc_name + prefix_len;
 960 }
 961
 962 static
 963 int lttng_syscall_filter_enable(
 964                 struct lttng_syscall_filter *filter,
 965                 const char *desc_name, enum lttng_syscall_abi abi,
 966                 enum lttng_syscall_entryexit entryexit)
 967 {
 968         const char *syscall_name;
 969         unsigned long *bitmap;
 970         int syscall_nr;
 971
 972         syscall_name = get_syscall_name(desc_name, abi, entryexit);
 973
 974         switch (abi) {
 975         case LTTNG_SYSCALL_ABI_NATIVE:
 976                 syscall_nr = get_syscall_nr(syscall_name);
 977                 break;
 978         case LTTNG_SYSCALL_ABI_COMPAT:
 979                 syscall_nr = get_compat_syscall_nr(syscall_name);
 980                 break;
 981         default:
 982                 return -EINVAL;
 983         }
 984         if (syscall_nr < 0)
 985                 return -ENOENT;
 986
 987         switch (entryexit) {
 988         case LTTNG_SYSCALL_ENTRY:
 989                 switch (abi) {
 990                 case LTTNG_SYSCALL_ABI_NATIVE:
 991                         bitmap = filter->sc_entry;
 992                         break;
 993                 case LTTNG_SYSCALL_ABI_COMPAT:
 994                         bitmap = filter->sc_compat_entry;
 995                         break;
 996                 default:
 997                         return -EINVAL;
 998                 }
 999                 break;
1000         case LTTNG_SYSCALL_EXIT:
1001                 switch (abi) {
1002                 case LTTNG_SYSCALL_ABI_NATIVE:
1003                         bitmap = filter->sc_exit;
1004                         break;
1005                 case LTTNG_SYSCALL_ABI_COMPAT:
1006                         bitmap = filter->sc_compat_exit;
1007                         break;
1008                 default:
1009                         return -EINVAL;
1010                 }
1011                 break;
1012         default:
1013                 return -EINVAL;
1014         }
1015         if (test_bit(syscall_nr, bitmap))
1016                 return -EEXIST;
1017         bitmap_set(bitmap, syscall_nr, 1);
1018         return 0;
1019 }
1020
1021 int lttng_syscall_filter_enable_event(struct lttng_kernel_event_common *event)
1022 {
1023         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
1024         unsigned int syscall_id = event->priv->u.syscall.syscall_id;
1025         struct hlist_head *dispatch_list;
1026         int ret;
1027
1028         WARN_ON_ONCE(event->priv->instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
1029
1030         ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
1031                 event->priv->desc->event_name, event->priv->u.syscall.abi,
1032                 event->priv->u.syscall.entryexit);
1033         if (ret)
1034                 return ret;
1035
1036         switch (event->priv->u.syscall.entryexit) {
1037         case LTTNG_SYSCALL_ENTRY:
1038                 switch (event->priv->u.syscall.abi) {
1039                 case LTTNG_SYSCALL_ABI_NATIVE:
1040                         dispatch_list = &syscall_table->syscall_dispatch[syscall_id];
1041                         break;
1042                 case LTTNG_SYSCALL_ABI_COMPAT:
1043                         dispatch_list = &syscall_table->compat_syscall_dispatch[syscall_id];
1044                         break;
1045                 default:
1046                         ret = -EINVAL;
1047                         goto end;
1048                 }
1049                 break;
1050         case LTTNG_SYSCALL_EXIT:
1051                 switch (event->priv->u.syscall.abi) {
1052                 case LTTNG_SYSCALL_ABI_NATIVE:
1053                         dispatch_list = &syscall_table->syscall_exit_dispatch[syscall_id];
1054                         break;
1055                 case LTTNG_SYSCALL_ABI_COMPAT:
1056                         dispatch_list = &syscall_table->compat_syscall_exit_dispatch[syscall_id];
1057                         break;
1058                 default:
1059                         ret = -EINVAL;
1060                         goto end;
1061                 }
1062                 break;
1063         default:
1064                 ret = -EINVAL;
1065                 goto end;
1066         }
1067
1068         hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_list);
1069 end:
1070         return ret;
1071 }
1072
1073 static
1074 int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
1075                 const char *desc_name, enum lttng_syscall_abi abi,
1076                 enum lttng_syscall_entryexit entryexit)
1077 {
1078         const char *syscall_name;
1079         unsigned long *bitmap;
1080         int syscall_nr;
1081
1082         syscall_name = get_syscall_name(desc_name, abi, entryexit);
1083
1084         switch (abi) {
1085         case LTTNG_SYSCALL_ABI_NATIVE:
1086                 syscall_nr = get_syscall_nr(syscall_name);
1087                 break;
1088         case LTTNG_SYSCALL_ABI_COMPAT:
1089                 syscall_nr = get_compat_syscall_nr(syscall_name);
1090                 break;
1091         default:
1092                 return -EINVAL;
1093         }
1094         if (syscall_nr < 0)
1095                 return -ENOENT;
1096
1097         switch (entryexit) {
1098         case LTTNG_SYSCALL_ENTRY:
1099                 switch (abi) {
1100                 case LTTNG_SYSCALL_ABI_NATIVE:
1101                         bitmap = filter->sc_entry;
1102                         break;
1103                 case LTTNG_SYSCALL_ABI_COMPAT:
1104                         bitmap = filter->sc_compat_entry;
1105                         break;
1106                 default:
1107                         return -EINVAL;
1108                 }
1109                 break;
1110         case LTTNG_SYSCALL_EXIT:
1111                 switch (abi) {
1112                 case LTTNG_SYSCALL_ABI_NATIVE:
1113                         bitmap = filter->sc_exit;
1114                         break;
1115                 case LTTNG_SYSCALL_ABI_COMPAT:
1116                         bitmap = filter->sc_compat_exit;
1117                         break;
1118                 default:
1119                         return -EINVAL;
1120                 }
1121                 break;
1122         default:
1123                 return -EINVAL;
1124         }
1125         if (!test_bit(syscall_nr, bitmap))
1126                 return -EEXIST;
1127         bitmap_clear(bitmap, syscall_nr, 1);
1128
1129         return 0;
1130 }
1131
1132 int lttng_syscall_filter_disable_event(struct lttng_kernel_event_common *event)
1133 {
1134         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
1135         int ret;
1136
1137         ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
1138                 event->priv->desc->event_name, event->priv->u.syscall.abi,
1139                 event->priv->u.syscall.entryexit);
1140         if (ret)
1141                 return ret;
1142         hlist_del_rcu(&event->priv->u.syscall.node);
1143         return 0;
1144 }
1145
1146 void lttng_syscall_table_set_wildcard_all(struct lttng_event_enabler_common *event_enabler)
1147 {
1148         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(event_enabler);
1149         enum lttng_kernel_abi_syscall_entryexit entryexit;
1150         int enabled = event_enabler->enabled;
1151
1152         if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
1153                 return;
1154         entryexit = event_enabler->event_param.u.syscall.entryexit;
1155         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
1156                 WRITE_ONCE(syscall_table->syscall_all_entry, enabled);
1157
1158         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
1159                 WRITE_ONCE(syscall_table->syscall_all_exit, enabled);
1160 }
1161
1162 static
1163 const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
1164 {
1165         const struct trace_syscall_entry *entry;
1166         int iter = 0;
1167
1168         for (entry = sc_table.table;
1169                         entry < sc_table.table + sc_table.len;
1170                          entry++) {
1171                 if (iter++ >= *pos)
1172                         return entry;
1173         }
1174         for (entry = compat_sc_table.table;
1175                         entry < compat_sc_table.table + compat_sc_table.len;
1176                          entry++) {
1177                 if (iter++ >= *pos)
1178                         return entry;
1179         }
1180         /* End of list */
1181         return NULL;
1182 }
1183
1184 static
1185 void *syscall_list_start(struct seq_file *m, loff_t *pos)
1186 {
1187         return (void *) syscall_list_get_entry(pos);
1188 }
1189
1190 static
1191 void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
1192 {
1193         (*ppos)++;
1194         return (void *) syscall_list_get_entry(ppos);
1195 }
1196
1197 static
1198 void syscall_list_stop(struct seq_file *m, void *p)
1199 {
1200 }
1201
1202 static
1203 int get_sc_table(const struct trace_syscall_entry *entry,
1204                 const struct trace_syscall_entry **table,
1205                 unsigned int *bitness)
1206 {
1207         if (entry >= sc_table.table && entry < sc_table.table + sc_table.len) {
1208                 if (bitness)
1209                         *bitness = BITS_PER_LONG;
1210                 if (table)
1211                         *table = sc_table.table;
1212                 return 0;
1213         }
1214         if (!(entry >= compat_sc_table.table
1215                         && entry < compat_sc_table.table + compat_sc_table.len)) {
1216                 return -EINVAL;
1217         }
1218         if (bitness)
1219                 *bitness = 32;
1220         if (table)
1221                 *table = compat_sc_table.table;
1222         return 0;
1223 }
1224
1225 static
1226 int syscall_list_show(struct seq_file *m, void *p)
1227 {
1228         const struct trace_syscall_entry *table, *entry = p;
1229         unsigned int bitness;
1230         unsigned long index;
1231         int ret;
1232         const char *name;
1233
1234         ret = get_sc_table(entry, &table, &bitness);
1235         if (ret)
1236                 return ret;
1237         if (!entry->desc)
1238                 return 0;
1239         if (table == sc_table.table) {
1240                 index = entry - table;
1241                 name = &entry->desc->event_name[strlen(SYSCALL_ENTRY_STR)];
1242         } else {
1243                 index = (entry - table) + sc_table.len;
1244                 name = &entry->desc->event_name[strlen(COMPAT_SYSCALL_ENTRY_STR)];
1245         }
1246         seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
1247                 index, name, bitness);
1248         return 0;
1249 }
1250
1251 static
1252 const struct seq_operations lttng_syscall_list_seq_ops = {
1253         .start = syscall_list_start,
1254         .next = syscall_list_next,
1255         .stop = syscall_list_stop,
1256         .show = syscall_list_show,
1257 };
1258
1259 static
1260 int lttng_syscall_list_open(struct inode *inode, struct file *file)
1261 {
1262         return seq_open(file, &lttng_syscall_list_seq_ops);
1263 }
1264
1265 const struct file_operations lttng_syscall_list_fops = {
1266         .owner = THIS_MODULE,
1267         .open = lttng_syscall_list_open,
1268         .read = seq_read,
1269         .llseek = seq_lseek,
1270         .release = seq_release,
1271 };
1272
1273 /*
1274  * A syscall is enabled if it is traced for either entry or exit.
1275  */
1276 long lttng_syscall_table_get_active_mask(struct lttng_kernel_syscall_table *syscall_table,
1277                 struct lttng_kernel_abi_syscall_mask __user *usyscall_mask)
1278 {
1279         uint32_t len, sc_tables_len, bitmask_len;
1280         int ret = 0, bit;
1281         char *tmp_mask;
1282         struct lttng_syscall_filter *filter;
1283
1284         ret = get_user(len, &usyscall_mask->len);
1285         if (ret)
1286                 return ret;
1287         sc_tables_len = get_sc_tables_len();
1288         bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
1289         if (len < sc_tables_len) {
1290                 return put_user(sc_tables_len, &usyscall_mask->len);
1291         }
1292         /* Array is large enough, we can copy array to user-space. */
1293         tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
1294         if (!tmp_mask)
1295                 return -ENOMEM;
1296         filter = syscall_table->sc_filter;
1297
1298         for (bit = 0; bit < sc_table.len; bit++) {
1299                 char state;
1300
1301                 if (syscall_table->syscall_dispatch) {
1302                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1303                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1304                                 state = test_bit(bit, filter->sc_entry)
1305                                         || test_bit(bit, filter->sc_exit);
1306                         else
1307                                 state = 1;
1308                 } else {
1309                         state = 0;
1310                 }
1311                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1312         }
1313         for (; bit < sc_tables_len; bit++) {
1314                 char state;
1315
1316                 if (syscall_table->compat_syscall_dispatch) {
1317                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1318                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1319                                 state = test_bit(bit - sc_table.len,
1320                                                 filter->sc_compat_entry)
1321                                         || test_bit(bit - sc_table.len,
1322                                                 filter->sc_compat_exit);
1323                         else
1324                                 state = 1;
1325                 } else {
1326                         state = 0;
1327                 }
1328                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1329         }
1330         if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
1331                 ret = -EFAULT;
1332         kfree(tmp_mask);
1333         return ret;
1334 }
1335
1336 int lttng_abi_syscall_list(void)
1337 {
1338         struct file *syscall_list_file;
1339         int file_fd, ret;
1340
1341         file_fd = lttng_get_unused_fd();
1342         if (file_fd < 0) {
1343                 ret = file_fd;
1344                 goto fd_error;
1345         }
1346
1347         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
1348                                           &lttng_syscall_list_fops,
1349                                           NULL, O_RDWR);
1350         if (IS_ERR(syscall_list_file)) {
1351                 ret = PTR_ERR(syscall_list_file);
1352                 goto file_error;
1353         }
1354         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
1355         if (ret < 0)
1356                 goto open_error;
1357         fd_install(file_fd, syscall_list_file);
1358         return file_fd;
1359
1360 open_error:
1361         fput(syscall_list_file);
1362 file_error:
1363         put_unused_fd(file_fd);
1364 fd_error:
1365         return ret;
1366 }