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/rcu.h>
  29 #include <wrapper/syscall.h>
  30 #include <wrapper/limits.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 #ifdef IA32_NR_syscalls
  69 #define NR_compat_syscalls IA32_NR_syscalls
  70 #else
  71 #define NR_compat_syscalls NR_syscalls
  72 #endif
  73
  74 /*
  75  * Create LTTng tracepoint probes.
  76  */
  77 #define LTTNG_PACKAGE_BUILD
  78 #define CREATE_TRACE_POINTS
  79 #define TP_MODULE_NOINIT
  80 #define TRACE_INCLUDE_PATH instrumentation/syscalls/headers
  81
  82 #define PARAMS(args...) args
  83
  84 /* Handle unknown syscalls */
  85 #undef TRACE_SYSTEM
  86 #define TRACE_SYSTEM syscalls_unknown
  87 #include <instrumentation/syscalls/headers/syscalls_unknown.h>
  88 #undef TRACE_SYSTEM
  89
  90 #undef TP_PROBE_CB
  91
  92 extern const struct trace_syscall_table sc_table;
  93 extern const struct trace_syscall_table compat_sc_table;
  94
  95 /* Event syscall exit table */
  96 extern const struct trace_syscall_table sc_exit_table;
  97 extern const struct trace_syscall_table compat_sc_exit_table;
  98
  99
 100 #undef SC_EXIT
 101
 102 #undef CREATE_SYSCALL_TABLE
 103
 104 struct lttng_syscall_filter {
 105         DECLARE_BITMAP(sc_entry, NR_syscalls);
 106         DECLARE_BITMAP(sc_exit, NR_syscalls);
 107         DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
 108         DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
 109
 110         /*
 111          * Reference counters keeping track of number of events enabled
 112          * for each bit.
 113          */
 114         u32 sc_entry_refcount_map[NR_syscalls];
 115         u32 sc_exit_refcount_map[NR_syscalls];
 116         u32 sc_compat_entry_refcount_map[NR_compat_syscalls];
 117         u32 sc_compat_exit_refcount_map[NR_compat_syscalls];
 118 };
 119
 120 static void syscall_entry_event_unknown(struct hlist_head *unknown_action_list_head,
 121         struct pt_regs *regs, long id)
 122 {
 123         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 124         struct lttng_kernel_event_common_private *event_priv;
 125
 126         lttng_syscall_get_arguments(current, regs, args);
 127         lttng_hlist_for_each_entry_rcu(event_priv, unknown_action_list_head, u.syscall.node) {
 128                 if (unlikely(in_compat_syscall()))
 129                         __event_probe__compat_syscall_entry_unknown(event_priv->pub, id, args);
 130                 else
 131                         __event_probe__syscall_entry_unknown(event_priv->pub, id, args);
 132         }
 133 }
 134
 135 static __always_inline
 136 void syscall_entry_event_call_func(struct hlist_head *action_list,
 137                 void *func, unsigned int nrargs,
 138                 struct pt_regs *regs)
 139 {
 140         struct lttng_kernel_event_common_private *event_priv;
 141
 142         switch (nrargs) {
 143         case 0:
 144         {
 145                 void (*fptr)(void *__data) = func;
 146
 147                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 148                         fptr(event_priv->pub);
 149                 break;
 150         }
 151         case 1:
 152         {
 153                 void (*fptr)(void *__data, unsigned long arg0) = func;
 154                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 155
 156                 lttng_syscall_get_arguments(current, regs, args);
 157                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 158                         fptr(event_priv->pub, args[0]);
 159                 break;
 160         }
 161         case 2:
 162         {
 163                 void (*fptr)(void *__data,
 164                         unsigned long arg0,
 165                         unsigned long arg1) = func;
 166                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 167
 168                 lttng_syscall_get_arguments(current, regs, args);
 169                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 170                         fptr(event_priv->pub, args[0], args[1]);
 171                 break;
 172         }
 173         case 3:
 174         {
 175                 void (*fptr)(void *__data,
 176                         unsigned long arg0,
 177                         unsigned long arg1,
 178                         unsigned long arg2) = func;
 179                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 180
 181                 lttng_syscall_get_arguments(current, regs, args);
 182                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 183                         fptr(event_priv->pub, args[0], args[1], args[2]);
 184                 break;
 185         }
 186         case 4:
 187         {
 188                 void (*fptr)(void *__data,
 189                         unsigned long arg0,
 190                         unsigned long arg1,
 191                         unsigned long arg2,
 192                         unsigned long arg3) = func;
 193                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 194
 195                 lttng_syscall_get_arguments(current, regs, args);
 196                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 197                         fptr(event_priv->pub, args[0], args[1], args[2], args[3]);
 198                 break;
 199         }
 200         case 5:
 201         {
 202                 void (*fptr)(void *__data,
 203                         unsigned long arg0,
 204                         unsigned long arg1,
 205                         unsigned long arg2,
 206                         unsigned long arg3,
 207                         unsigned long arg4) = 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], args[4]);
 213                 break;
 214         }
 215         case 6:
 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,
 223                         unsigned long arg5) = func;
 224                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 225
 226                 lttng_syscall_get_arguments(current, regs, args);
 227                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 228                         fptr(event_priv->pub, args[0], args[1], args[2],
 229                              args[3], args[4], args[5]);
 230                 break;
 231         }
 232         default:
 233                 break;
 234         }
 235 }
 236
 237 void syscall_entry_event_probe(void *__data, struct pt_regs *regs, long id)
 238 {
 239         struct lttng_kernel_syscall_table *syscall_table = __data;
 240         struct hlist_head *action_list, *unknown_action_list;
 241         const struct trace_syscall_entry *table, *entry;
 242         size_t table_len;
 243
 244         if (unlikely(in_compat_syscall())) {
 245                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 246
 247                 if (id < 0 || id >= NR_compat_syscalls
 248                         || (!READ_ONCE(syscall_table->syscall_all_entry) && !test_bit(id, filter->sc_compat_entry))) {
 249                         /* System call filtered out. */
 250                         return;
 251                 }
 252                 table = compat_sc_table.table;
 253                 table_len = compat_sc_table.len;
 254                 unknown_action_list = &syscall_table->compat_unknown_syscall_dispatch;
 255         } else {
 256                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 257
 258                 if (id < 0 || id >= NR_syscalls
 259                         || (!READ_ONCE(syscall_table->syscall_all_entry) && !test_bit(id, filter->sc_entry))) {
 260                         /* System call filtered out. */
 261                         return;
 262                 }
 263                 table = sc_table.table;
 264                 table_len = sc_table.len;
 265                 unknown_action_list = &syscall_table->unknown_syscall_dispatch;
 266         }
 267         if (unlikely(id < 0 || id >= table_len)) {
 268                 syscall_entry_event_unknown(unknown_action_list, regs, id);
 269                 return;
 270         }
 271
 272         entry = &table[id];
 273         if (!entry->event_func) {
 274                 syscall_entry_event_unknown(unknown_action_list, regs, id);
 275                 return;
 276         }
 277
 278         if (unlikely(in_compat_syscall())) {
 279                 action_list = &syscall_table->compat_syscall_dispatch[id];
 280         } else {
 281                 action_list = &syscall_table->syscall_dispatch[id];
 282         }
 283         if (unlikely(hlist_empty(action_list)))
 284                 return;
 285
 286         syscall_entry_event_call_func(action_list, entry->event_func, entry->nrargs, regs);
 287 }
 288
 289 static void syscall_exit_event_unknown(struct hlist_head *unknown_action_list_head,
 290         struct pt_regs *regs, long id, long ret)
 291 {
 292         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 293         struct lttng_kernel_event_common_private *event_priv;
 294
 295         lttng_syscall_get_arguments(current, regs, args);
 296         lttng_hlist_for_each_entry_rcu(event_priv, unknown_action_list_head, u.syscall.node) {
 297                 if (unlikely(in_compat_syscall()))
 298                         __event_probe__compat_syscall_exit_unknown(event_priv->pub, id, ret,
 299                                 args);
 300                 else
 301                         __event_probe__syscall_exit_unknown(event_priv->pub, id, ret, args);
 302         }
 303 }
 304
 305 static __always_inline
 306 void syscall_exit_event_call_func(struct hlist_head *action_list,
 307                 void *func, unsigned int nrargs,
 308                 struct pt_regs *regs, long ret)
 309 {
 310         struct lttng_kernel_event_common_private *event_priv;
 311
 312         switch (nrargs) {
 313         case 0:
 314         {
 315                 void (*fptr)(void *__data, long ret) = func;
 316
 317                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 318                         fptr(event_priv->pub, ret);
 319                 break;
 320         }
 321         case 1:
 322         {
 323                 void (*fptr)(void *__data,
 324                         long ret,
 325                         unsigned long arg0) = func;
 326                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 327
 328                 lttng_syscall_get_arguments(current, regs, args);
 329                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 330                         fptr(event_priv->pub, ret, args[0]);
 331                 break;
 332         }
 333         case 2:
 334         {
 335                 void (*fptr)(void *__data,
 336                         long ret,
 337                         unsigned long arg0,
 338                         unsigned long arg1) = func;
 339                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 340
 341                 lttng_syscall_get_arguments(current, regs, args);
 342                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 343                         fptr(event_priv->pub, ret, args[0], args[1]);
 344                 break;
 345         }
 346         case 3:
 347         {
 348                 void (*fptr)(void *__data,
 349                         long ret,
 350                         unsigned long arg0,
 351                         unsigned long arg1,
 352                         unsigned long arg2) = func;
 353                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 354
 355                 lttng_syscall_get_arguments(current, regs, args);
 356                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 357                         fptr(event_priv->pub, ret, args[0], args[1], args[2]);
 358                 break;
 359         }
 360         case 4:
 361         {
 362                 void (*fptr)(void *__data,
 363                         long ret,
 364                         unsigned long arg0,
 365                         unsigned long arg1,
 366                         unsigned long arg2,
 367                         unsigned long arg3) = 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], args[3]);
 373                 break;
 374         }
 375         case 5:
 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,
 383                         unsigned long arg4) = func;
 384                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 385
 386                 lttng_syscall_get_arguments(current, regs, args);
 387                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 388                         fptr(event_priv->pub, ret, args[0], args[1], args[2], args[3], args[4]);
 389                 break;
 390         }
 391         case 6:
 392         {
 393                 void (*fptr)(void *__data,
 394                         long ret,
 395                         unsigned long arg0,
 396                         unsigned long arg1,
 397                         unsigned long arg2,
 398                         unsigned long arg3,
 399                         unsigned long arg4,
 400                         unsigned long arg5) = func;
 401                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 402
 403                 lttng_syscall_get_arguments(current, regs, args);
 404                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 405                         fptr(event_priv->pub, ret, args[0], args[1], args[2],
 406                              args[3], args[4], args[5]);
 407                 break;
 408         }
 409         default:
 410                 break;
 411         }
 412 }
 413
 414 void syscall_exit_event_probe(void *__data, struct pt_regs *regs, long ret)
 415 {
 416         struct lttng_kernel_syscall_table *syscall_table = __data;
 417         struct hlist_head *action_list, *unknown_action_list;
 418         const struct trace_syscall_entry *table, *entry;
 419         size_t table_len;
 420         long id;
 421
 422         id = syscall_get_nr(current, regs);
 423
 424         if (unlikely(in_compat_syscall())) {
 425                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 426
 427                 if (id < 0 || id >= NR_compat_syscalls
 428                         || (!READ_ONCE(syscall_table->syscall_all_exit) && !test_bit(id, filter->sc_compat_exit))) {
 429                         /* System call filtered out. */
 430                         return;
 431                 }
 432                 table = compat_sc_exit_table.table;
 433                 table_len = compat_sc_exit_table.len;
 434                 unknown_action_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
 435         } else {
 436                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 437
 438                 if (id < 0 || id >= NR_syscalls
 439                         || (!READ_ONCE(syscall_table->syscall_all_exit) && !test_bit(id, filter->sc_exit))) {
 440                         /* System call filtered out. */
 441                         return;
 442                 }
 443                 table = sc_exit_table.table;
 444                 table_len = sc_exit_table.len;
 445                 unknown_action_list = &syscall_table->unknown_syscall_exit_dispatch;
 446         }
 447         if (unlikely(id < 0 || id >= table_len)) {
 448                 syscall_exit_event_unknown(unknown_action_list, regs, id, ret);
 449                 return;
 450         }
 451
 452         entry = &table[id];
 453         if (!entry->event_func) {
 454                 syscall_exit_event_unknown(unknown_action_list, regs, id, ret);
 455                 return;
 456         }
 457
 458         if (unlikely(in_compat_syscall())) {
 459                 action_list = &syscall_table->compat_syscall_exit_dispatch[id];
 460         } else {
 461                 action_list = &syscall_table->syscall_exit_dispatch[id];
 462         }
 463         if (unlikely(hlist_empty(action_list)))
 464                 return;
 465
 466         syscall_exit_event_call_func(action_list, entry->event_func, entry->nrargs,
 467                                regs, ret);
 468 }
 469
 470 static
 471 struct lttng_kernel_syscall_table *get_syscall_table_from_enabler(struct lttng_event_enabler_common *event_enabler)
 472 {
 473         switch (event_enabler->enabler_type) {
 474         case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
 475         {
 476                 struct lttng_event_recorder_enabler *event_recorder_enabler =
 477                         container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
 478                 return &event_recorder_enabler->chan->priv->parent.syscall_table;
 479         }
 480         case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
 481         {
 482                 struct lttng_event_notifier_enabler *event_notifier_enabler =
 483                         container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
 484                 return &event_notifier_enabler->group->syscall_table;
 485         }
 486         default:
 487                 return NULL;
 488         }
 489 }
 490
 491 static
 492 struct lttng_kernel_syscall_table *get_syscall_table_from_event(struct lttng_kernel_event_common *event)
 493 {
 494         switch (event->type) {
 495         case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
 496         {
 497                 struct lttng_kernel_event_recorder *event_recorder =
 498                         container_of(event, struct lttng_kernel_event_recorder, parent);
 499                 return &event_recorder->chan->priv->parent.syscall_table;
 500         }
 501         case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
 502         {
 503                 struct lttng_kernel_event_notifier *event_notifier =
 504                         container_of(event, struct lttng_kernel_event_notifier, parent);
 505                 return &event_notifier->priv->group->syscall_table;
 506         }
 507         default:
 508                 return NULL;
 509         }
 510 }
 511
 512 static
 513 void lttng_syscall_event_enabler_create_event(struct lttng_event_enabler_common *syscall_event_enabler,
 514                 const struct lttng_kernel_event_desc *desc, enum sc_type type, unsigned int syscall_nr)
 515 {
 516         struct lttng_kernel_event_common *event;
 517
 518         switch (syscall_event_enabler->enabler_type) {
 519         case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
 520         {
 521                 struct lttng_event_recorder_enabler *syscall_event_recorder_enabler =
 522                         container_of(syscall_event_enabler, struct lttng_event_recorder_enabler, parent);
 523                 struct lttng_event_recorder_enabler *event_recorder_enabler;
 524                 struct lttng_kernel_abi_event ev;
 525
 526                 /* We need to create an event for this syscall/enabler. */
 527                 memset(&ev, 0, sizeof(ev));
 528                 switch (type) {
 529                 case SC_TYPE_ENTRY:
 530                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 531                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 532                         break;
 533                 case SC_TYPE_EXIT:
 534                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 535                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 536                         break;
 537                 case SC_TYPE_COMPAT_ENTRY:
 538                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 539                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 540                         break;
 541                 case SC_TYPE_COMPAT_EXIT:
 542                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 543                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 544                         break;
 545                 }
 546                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1);
 547                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 548                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 549                 event_recorder_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev,
 550                                 syscall_event_recorder_enabler->chan);
 551                 WARN_ON_ONCE(!event_recorder_enabler);
 552                 if (!event_recorder_enabler)
 553                         return;
 554                 event = _lttng_kernel_event_create(&event_recorder_enabler->parent, desc);
 555                 WARN_ON_ONCE(IS_ERR(event));
 556                 lttng_event_enabler_destroy(&event_recorder_enabler->parent);
 557                 if (IS_ERR(event)) {
 558                         printk(KERN_INFO "Unable to create event recorder %s\n", desc->event_name);
 559                         return;
 560                 }
 561                 event->priv->u.syscall.syscall_id = syscall_nr;
 562                 break;
 563         }
 564         case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
 565         {
 566                 struct lttng_event_notifier_enabler *syscall_event_notifier_enabler =
 567                         container_of(syscall_event_enabler, struct lttng_event_notifier_enabler, parent);
 568                 struct lttng_event_notifier_enabler *event_notifier_enabler;
 569                 struct lttng_kernel_abi_event_notifier event_notifier_param;
 570                 uint64_t user_token = syscall_event_enabler->user_token;
 571                 uint64_t error_counter_index = syscall_event_notifier_enabler->error_counter_index;
 572
 573                 memset(&event_notifier_param, 0, sizeof(event_notifier_param));
 574                 switch (type) {
 575                 case SC_TYPE_ENTRY:
 576                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 577                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 578                         break;
 579                 case SC_TYPE_EXIT:
 580                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 581                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 582                         break;
 583                 case SC_TYPE_COMPAT_ENTRY:
 584                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 585                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 586                         break;
 587                 case SC_TYPE_COMPAT_EXIT:
 588                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 589                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 590                         break;
 591                 }
 592                 strncat(event_notifier_param.event.name, desc->event_name,
 593                         LTTNG_KERNEL_ABI_SYM_NAME_LEN - strlen(event_notifier_param.event.name) - 1);
 594                 event_notifier_param.event.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 595                 event_notifier_param.event.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 596                 event_notifier_param.event.token = user_token;
 597                 event_notifier_param.error_counter_index = error_counter_index;
 598
 599                 event_notifier_enabler = lttng_event_notifier_enabler_create(LTTNG_ENABLER_FORMAT_NAME,
 600                                 &event_notifier_param, syscall_event_notifier_enabler->group);
 601                 WARN_ON_ONCE(!event_notifier_enabler);
 602                 event = _lttng_kernel_event_create(&event_notifier_enabler->parent, desc);
 603                 WARN_ON_ONCE(IS_ERR(event));
 604                 lttng_event_enabler_destroy(&event_notifier_enabler->parent);
 605                 if (IS_ERR(event)) {
 606                         printk(KERN_INFO "Unable to create event notifier %s\n", desc->event_name);
 607                         return;
 608                 }
 609                 event->priv->u.syscall.syscall_id = syscall_nr;
 610                 break;
 611         }
 612         default:
 613                 break;
 614         }
 615 }
 616
 617 static
 618 void lttng_syscall_event_enabler_create_matching_syscall_table_events(struct lttng_event_enabler_common *syscall_event_enabler_common,
 619                 const struct trace_syscall_entry *table, size_t table_len, enum sc_type type)
 620 {
 621         struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(syscall_event_enabler_common);
 622         const struct lttng_kernel_event_desc *desc;
 623         unsigned int i;
 624
 625 #ifndef CONFIG_COMPAT
 626         if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
 627                 return;
 628 #endif
 629         /* iterate over all syscall and create event that match */
 630         for (i = 0; i < table_len; i++) {
 631                 struct lttng_kernel_event_common_private *event_priv;
 632                 struct hlist_head *head;
 633                 bool found = false;
 634
 635                 desc = table[i].desc;
 636                 if (!desc) {
 637                         /* Unknown syscall */
 638                         continue;
 639                 }
 640
 641                 if (!lttng_desc_match_enabler(desc, syscall_event_enabler_common))
 642                         continue;
 643
 644                 /*
 645                  * Check if already created.
 646                  */
 647                 head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 648                 lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
 649                         if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub)) {
 650                                 found = true;
 651                                 break;
 652                         }
 653                 }
 654                 if (found)
 655                         continue;
 656
 657                 lttng_syscall_event_enabler_create_event(syscall_event_enabler_common, desc, type, i);
 658         }
 659 }
 660
 661 static
 662 bool lttng_syscall_event_enabler_is_wildcard_all(struct lttng_event_enabler_common *event_enabler)
 663 {
 664         if (event_enabler->event_param.instrumentation != LTTNG_KERNEL_ABI_SYSCALL)
 665                 return false;
 666         if (event_enabler->event_param.u.syscall.abi != LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL)
 667                 return false;
 668         if (event_enabler->event_param.u.syscall.match != LTTNG_KERNEL_ABI_SYSCALL_MATCH_NAME)
 669                 return false;
 670         if (strcmp(event_enabler->event_param.name, "*"))
 671                 return false;
 672         return true;
 673 }
 674
 675 static
 676 void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabler, enum sc_type type)
 677 {
 678         struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(event_enabler);
 679         struct lttng_kernel_event_common_private *event_priv;
 680         const struct lttng_kernel_event_desc *desc;
 681         bool found = false;
 682         struct hlist_head *head;
 683
 684 #ifndef CONFIG_COMPAT
 685         if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
 686                 return;
 687 #endif
 688         /*
 689          * Considering that currently system calls can only be enabled on a per
 690          * name basis (or wildcard based on a name), unknown syscall events are
 691          * only used when matching *all* system calls, because this is the only
 692          * case which can be associated with an unknown system call.
 693          *
 694          * When enabling system call on a per system call number basis will be
 695          * supported, this will need to be revisited.
 696          */
 697         if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
 698                 return;
 699
 700         switch (type) {
 701         case SC_TYPE_ENTRY:
 702                 desc = &__event_desc___syscall_entry_unknown;
 703                 break;
 704         case SC_TYPE_EXIT:
 705                 desc = &__event_desc___syscall_exit_unknown;
 706                 break;
 707         case SC_TYPE_COMPAT_ENTRY:
 708                 desc = &__event_desc___compat_syscall_entry_unknown;
 709                 break;
 710         case SC_TYPE_COMPAT_EXIT:
 711                 desc = &__event_desc___compat_syscall_exit_unknown;
 712                 break;
 713         default:
 714                 WARN_ON_ONCE(1);
 715         }
 716
 717         /*
 718          * Check if already created.
 719          */
 720         head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 721         lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
 722                 if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub)) {
 723                         found = true;
 724                         break;
 725                 }
 726         }
 727         if (!found)
 728                 lttng_syscall_event_enabler_create_event(event_enabler, desc, type, -1U);
 729 }
 730
 731 static
 732 void lttng_syscall_event_enabler_create_matching_events(struct lttng_event_enabler_common *event_enabler)
 733 {
 734         enum lttng_kernel_abi_syscall_entryexit entryexit = event_enabler->event_param.u.syscall.entryexit;
 735
 736         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
 737                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 738                         sc_table.table, sc_table.len, SC_TYPE_ENTRY);
 739                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 740                         compat_sc_table.table, compat_sc_table.len, SC_TYPE_COMPAT_ENTRY);
 741                 create_unknown_syscall_event(event_enabler, SC_TYPE_ENTRY);
 742                 create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_ENTRY);
 743         }
 744
 745         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
 746                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 747                         sc_exit_table.table, sc_exit_table.len, SC_TYPE_EXIT);
 748                 lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
 749                         compat_sc_exit_table.table, compat_sc_exit_table.len, SC_TYPE_COMPAT_EXIT);
 750                 create_unknown_syscall_event(event_enabler, SC_TYPE_EXIT);
 751                 create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_EXIT);
 752         }
 753 }
 754
 755 /*
 756  * Should be called with sessions lock held.
 757  */
 758 int lttng_event_enabler_create_syscall_events_if_missing(struct lttng_event_enabler_common *syscall_event_enabler)
 759 {
 760         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(syscall_event_enabler);
 761         int ret;
 762
 763         if (!syscall_table->syscall_dispatch) {
 764                 /* create syscall table mapping syscall to events */
 765                 syscall_table->syscall_dispatch = kzalloc(sizeof(struct hlist_head) * sc_table.len, GFP_KERNEL);
 766                 if (!syscall_table->syscall_dispatch)
 767                         return -ENOMEM;
 768         }
 769         if (!syscall_table->syscall_exit_dispatch) {
 770                 /* create syscall table mapping syscall to events */
 771                 syscall_table->syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * sc_exit_table.len, GFP_KERNEL);
 772                 if (!syscall_table->syscall_exit_dispatch)
 773                         return -ENOMEM;
 774         }
 775
 776 #ifdef CONFIG_COMPAT
 777         if (!syscall_table->compat_syscall_dispatch) {
 778                 /* create syscall table mapping compat syscall to events */
 779                 syscall_table->compat_syscall_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_table.len, GFP_KERNEL);
 780                 if (!syscall_table->compat_syscall_dispatch)
 781                         return -ENOMEM;
 782         }
 783
 784         if (!syscall_table->compat_syscall_exit_dispatch) {
 785                 /* create syscall table mapping compat syscall to events */
 786                 syscall_table->compat_syscall_exit_dispatch = kzalloc(sizeof(struct hlist_head) * compat_sc_exit_table.len, GFP_KERNEL);
 787                 if (!syscall_table->compat_syscall_exit_dispatch)
 788                         return -ENOMEM;
 789         }
 790 #endif
 791         if (!syscall_table->sc_filter) {
 792                 syscall_table->sc_filter = kzalloc(sizeof(struct lttng_syscall_filter),
 793                                 GFP_KERNEL);
 794                 if (!syscall_table->sc_filter)
 795                         return -ENOMEM;
 796         }
 797
 798         if (!syscall_table->sys_enter_registered) {
 799                 ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
 800                                 (void *) syscall_entry_event_probe, syscall_table);
 801                 if (ret)
 802                         return ret;
 803                 syscall_table->sys_enter_registered = 1;
 804         }
 805         if (!syscall_table->sys_exit_registered) {
 806                 ret = lttng_wrapper_tracepoint_probe_register("sys_exit",
 807                                 (void *) syscall_exit_event_probe, syscall_table);
 808                 if (ret) {
 809                         WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 810                                 (void *) syscall_entry_event_probe, syscall_table));
 811                         return ret;
 812                 }
 813                 syscall_table->sys_exit_registered = 1;
 814         }
 815
 816         lttng_syscall_event_enabler_create_matching_events(syscall_event_enabler);
 817
 818         return 0;
 819 }
 820
 821 int lttng_syscalls_unregister_syscall_table(struct lttng_kernel_syscall_table *syscall_table)
 822 {
 823         int ret;
 824
 825         if (!syscall_table->syscall_dispatch)
 826                 return 0;
 827         if (syscall_table->sys_enter_registered) {
 828                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 829                                 (void *) syscall_entry_event_probe, syscall_table);
 830                 if (ret)
 831                         return ret;
 832                 syscall_table->sys_enter_registered = 0;
 833         }
 834         if (syscall_table->sys_exit_registered) {
 835                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
 836                                 (void *) syscall_exit_event_probe, syscall_table);
 837                 if (ret)
 838                         return ret;
 839                 syscall_table->sys_exit_registered = 0;
 840         }
 841         return 0;
 842 }
 843
 844 int lttng_syscalls_destroy_syscall_table(struct lttng_kernel_syscall_table *syscall_table)
 845 {
 846         kfree(syscall_table->syscall_dispatch);
 847         kfree(syscall_table->syscall_exit_dispatch);
 848 #ifdef CONFIG_COMPAT
 849         kfree(syscall_table->compat_syscall_dispatch);
 850         kfree(syscall_table->compat_syscall_exit_dispatch);
 851 #endif
 852         kfree(syscall_table->sc_filter);
 853         return 0;
 854 }
 855
 856 static
 857 uint32_t get_sc_tables_len(void)
 858 {
 859         return sc_table.len + compat_sc_table.len;
 860 }
 861
 862 static
 863 const char *get_syscall_name(const char *desc_name,
 864                 enum lttng_syscall_abi abi,
 865                 enum lttng_syscall_entryexit entryexit)
 866 {
 867         size_t prefix_len = 0;
 868
 869
 870         switch (entryexit) {
 871         case LTTNG_SYSCALL_ENTRY:
 872                 switch (abi) {
 873                 case LTTNG_SYSCALL_ABI_NATIVE:
 874                         prefix_len = strlen(SYSCALL_ENTRY_STR);
 875                         break;
 876                 case LTTNG_SYSCALL_ABI_COMPAT:
 877                         prefix_len = strlen(COMPAT_SYSCALL_ENTRY_STR);
 878                         break;
 879                 }
 880                 break;
 881         case LTTNG_SYSCALL_EXIT:
 882                 switch (abi) {
 883                 case LTTNG_SYSCALL_ABI_NATIVE:
 884                         prefix_len = strlen(SYSCALL_EXIT_STR);
 885                         break;
 886                 case LTTNG_SYSCALL_ABI_COMPAT:
 887                         prefix_len = strlen(COMPAT_SYSCALL_EXIT_STR);
 888                         break;
 889                 }
 890                 break;
 891         }
 892         WARN_ON_ONCE(prefix_len == 0);
 893         return desc_name + prefix_len;
 894 }
 895
 896 static
 897 int lttng_syscall_filter_enable(
 898                 struct lttng_syscall_filter *filter,
 899                 const char *desc_name, enum lttng_syscall_abi abi,
 900                 enum lttng_syscall_entryexit entryexit,
 901                 unsigned int syscall_id)
 902 {
 903         const char *syscall_name;
 904         unsigned long *bitmap;
 905         u32 *refcount_map;
 906
 907         syscall_name = get_syscall_name(desc_name, abi, entryexit);
 908
 909         switch (entryexit) {
 910         case LTTNG_SYSCALL_ENTRY:
 911                 switch (abi) {
 912                 case LTTNG_SYSCALL_ABI_NATIVE:
 913                         bitmap = filter->sc_entry;
 914                         refcount_map = filter->sc_entry_refcount_map;
 915                         break;
 916                 case LTTNG_SYSCALL_ABI_COMPAT:
 917                         bitmap = filter->sc_compat_entry;
 918                         refcount_map = filter->sc_compat_entry_refcount_map;
 919                         break;
 920                 default:
 921                         return -EINVAL;
 922                 }
 923                 break;
 924         case LTTNG_SYSCALL_EXIT:
 925                 switch (abi) {
 926                 case LTTNG_SYSCALL_ABI_NATIVE:
 927                         bitmap = filter->sc_exit;
 928                         refcount_map = filter->sc_exit_refcount_map;
 929                         break;
 930                 case LTTNG_SYSCALL_ABI_COMPAT:
 931                         bitmap = filter->sc_compat_exit;
 932                         refcount_map = filter->sc_compat_exit_refcount_map;
 933                         break;
 934                 default:
 935                         return -EINVAL;
 936                 }
 937                 break;
 938         default:
 939                 return -EINVAL;
 940         }
 941         if (refcount_map[syscall_id] == U32_MAX)
 942                 return -EOVERFLOW;
 943         if (refcount_map[syscall_id]++ == 0)
 944                 bitmap_set(bitmap, syscall_id, 1);
 945         return 0;
 946 }
 947
 948 int lttng_syscall_filter_enable_event(struct lttng_kernel_event_common *event)
 949 {
 950         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
 951         unsigned int syscall_id = event->priv->u.syscall.syscall_id;
 952         struct hlist_head *dispatch_list;
 953         int ret = 0;
 954
 955         WARN_ON_ONCE(event->priv->instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
 956
 957         /* Unknown syscall */
 958         if (syscall_id == -1U) {
 959                 switch (event->priv->u.syscall.entryexit) {
 960                 case LTTNG_SYSCALL_ENTRY:
 961                         switch (event->priv->u.syscall.abi) {
 962                         case LTTNG_SYSCALL_ABI_NATIVE:
 963                                 dispatch_list = &syscall_table->unknown_syscall_dispatch;
 964                                 break;
 965                         case LTTNG_SYSCALL_ABI_COMPAT:
 966                                 dispatch_list = &syscall_table->compat_unknown_syscall_dispatch;
 967                                 break;
 968                         default:
 969                                 ret = -EINVAL;
 970                                 goto end;
 971                         }
 972                         break;
 973                 case LTTNG_SYSCALL_EXIT:
 974                         switch (event->priv->u.syscall.abi) {
 975                         case LTTNG_SYSCALL_ABI_NATIVE:
 976                                 dispatch_list = &syscall_table->unknown_syscall_exit_dispatch;
 977                                 break;
 978                         case LTTNG_SYSCALL_ABI_COMPAT:
 979                                 dispatch_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
 980                                 break;
 981                         default:
 982                                 ret = -EINVAL;
 983                                 goto end;
 984                         }
 985                         break;
 986                 default:
 987                         ret = -EINVAL;
 988                         goto end;
 989                 }
 990         } else {
 991                 ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
 992                         event->priv->desc->event_name, event->priv->u.syscall.abi,
 993                         event->priv->u.syscall.entryexit, syscall_id);
 994                 if (ret)
 995                         return ret;
 996
 997                 switch (event->priv->u.syscall.entryexit) {
 998                 case LTTNG_SYSCALL_ENTRY:
 999                         switch (event->priv->u.syscall.abi) {
1000                         case LTTNG_SYSCALL_ABI_NATIVE:
1001                                 dispatch_list = &syscall_table->syscall_dispatch[syscall_id];
1002                                 break;
1003                         case LTTNG_SYSCALL_ABI_COMPAT:
1004                                 dispatch_list = &syscall_table->compat_syscall_dispatch[syscall_id];
1005                                 break;
1006                         default:
1007                                 ret = -EINVAL;
1008                                 goto end;
1009                         }
1010                         break;
1011                 case LTTNG_SYSCALL_EXIT:
1012                         switch (event->priv->u.syscall.abi) {
1013                         case LTTNG_SYSCALL_ABI_NATIVE:
1014                                 dispatch_list = &syscall_table->syscall_exit_dispatch[syscall_id];
1015                                 break;
1016                         case LTTNG_SYSCALL_ABI_COMPAT:
1017                                 dispatch_list = &syscall_table->compat_syscall_exit_dispatch[syscall_id];
1018                                 break;
1019                         default:
1020                                 ret = -EINVAL;
1021                                 goto end;
1022                         }
1023                         break;
1024                 default:
1025                         ret = -EINVAL;
1026                         goto end;
1027                 }
1028         }
1029
1030         hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_list);
1031 end:
1032         return ret;
1033 }
1034
1035 static
1036 int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
1037                 const char *desc_name, enum lttng_syscall_abi abi,
1038                 enum lttng_syscall_entryexit entryexit,
1039                 unsigned int syscall_id)
1040 {
1041         const char *syscall_name;
1042         unsigned long *bitmap;
1043         u32 *refcount_map;
1044
1045         syscall_name = get_syscall_name(desc_name, abi, entryexit);
1046
1047         switch (entryexit) {
1048         case LTTNG_SYSCALL_ENTRY:
1049                 switch (abi) {
1050                 case LTTNG_SYSCALL_ABI_NATIVE:
1051                         bitmap = filter->sc_entry;
1052                         refcount_map = filter->sc_entry_refcount_map;
1053                         break;
1054                 case LTTNG_SYSCALL_ABI_COMPAT:
1055                         bitmap = filter->sc_compat_entry;
1056                         refcount_map = filter->sc_compat_entry_refcount_map;
1057                         break;
1058                 default:
1059                         return -EINVAL;
1060                 }
1061                 break;
1062         case LTTNG_SYSCALL_EXIT:
1063                 switch (abi) {
1064                 case LTTNG_SYSCALL_ABI_NATIVE:
1065                         bitmap = filter->sc_exit;
1066                         refcount_map = filter->sc_exit_refcount_map;
1067                         break;
1068                 case LTTNG_SYSCALL_ABI_COMPAT:
1069                         bitmap = filter->sc_compat_exit;
1070                         refcount_map = filter->sc_compat_exit_refcount_map;
1071                         break;
1072                 default:
1073                         return -EINVAL;
1074                 }
1075                 break;
1076         default:
1077                 return -EINVAL;
1078         }
1079         if (refcount_map[syscall_id] == 0)
1080                 return -ENOENT;
1081         if (--refcount_map[syscall_id] == 0)
1082                 bitmap_clear(bitmap, syscall_id, 1);
1083         return 0;
1084 }
1085
1086 int lttng_syscall_filter_disable_event(struct lttng_kernel_event_common *event)
1087 {
1088         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
1089         unsigned int syscall_id = event->priv->u.syscall.syscall_id;
1090         int ret;
1091
1092         /* Except for unknown syscall */
1093         if (syscall_id != -1U) {
1094                 ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
1095                         event->priv->desc->event_name, event->priv->u.syscall.abi,
1096                         event->priv->u.syscall.entryexit, syscall_id);
1097                 if (ret)
1098                         return ret;
1099         }
1100         hlist_del_rcu(&event->priv->u.syscall.node);
1101         return 0;
1102 }
1103
1104 void lttng_syscall_table_set_wildcard_all(struct lttng_event_enabler_common *event_enabler)
1105 {
1106         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(event_enabler);
1107         enum lttng_kernel_abi_syscall_entryexit entryexit;
1108         int enabled = event_enabler->enabled;
1109
1110         if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
1111                 return;
1112         entryexit = event_enabler->event_param.u.syscall.entryexit;
1113         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
1114                 WRITE_ONCE(syscall_table->syscall_all_entry, enabled);
1115
1116         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
1117                 WRITE_ONCE(syscall_table->syscall_all_exit, enabled);
1118 }
1119
1120 static
1121 const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
1122 {
1123         const struct trace_syscall_entry *entry;
1124         int iter = 0;
1125
1126         for (entry = sc_table.table;
1127                         entry < sc_table.table + sc_table.len;
1128                          entry++) {
1129                 if (iter++ >= *pos)
1130                         return entry;
1131         }
1132         for (entry = compat_sc_table.table;
1133                         entry < compat_sc_table.table + compat_sc_table.len;
1134                          entry++) {
1135                 if (iter++ >= *pos)
1136                         return entry;
1137         }
1138         /* End of list */
1139         return NULL;
1140 }
1141
1142 static
1143 void *syscall_list_start(struct seq_file *m, loff_t *pos)
1144 {
1145         return (void *) syscall_list_get_entry(pos);
1146 }
1147
1148 static
1149 void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
1150 {
1151         (*ppos)++;
1152         return (void *) syscall_list_get_entry(ppos);
1153 }
1154
1155 static
1156 void syscall_list_stop(struct seq_file *m, void *p)
1157 {
1158 }
1159
1160 static
1161 int get_sc_table(const struct trace_syscall_entry *entry,
1162                 const struct trace_syscall_entry **table,
1163                 unsigned int *bitness)
1164 {
1165         if (entry >= sc_table.table && entry < sc_table.table + sc_table.len) {
1166                 if (bitness)
1167                         *bitness = BITS_PER_LONG;
1168                 if (table)
1169                         *table = sc_table.table;
1170                 return 0;
1171         }
1172         if (!(entry >= compat_sc_table.table
1173                         && entry < compat_sc_table.table + compat_sc_table.len)) {
1174                 return -EINVAL;
1175         }
1176         if (bitness)
1177                 *bitness = 32;
1178         if (table)
1179                 *table = compat_sc_table.table;
1180         return 0;
1181 }
1182
1183 static
1184 int syscall_list_show(struct seq_file *m, void *p)
1185 {
1186         const struct trace_syscall_entry *table, *entry = p;
1187         unsigned int bitness;
1188         unsigned long index;
1189         int ret;
1190         const char *name;
1191
1192         ret = get_sc_table(entry, &table, &bitness);
1193         if (ret)
1194                 return ret;
1195         if (!entry->desc)
1196                 return 0;
1197         if (table == sc_table.table) {
1198                 index = entry - table;
1199                 name = &entry->desc->event_name[strlen(SYSCALL_ENTRY_STR)];
1200         } else {
1201                 index = (entry - table) + sc_table.len;
1202                 name = &entry->desc->event_name[strlen(COMPAT_SYSCALL_ENTRY_STR)];
1203         }
1204         seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
1205                 index, name, bitness);
1206         return 0;
1207 }
1208
1209 static
1210 const struct seq_operations lttng_syscall_list_seq_ops = {
1211         .start = syscall_list_start,
1212         .next = syscall_list_next,
1213         .stop = syscall_list_stop,
1214         .show = syscall_list_show,
1215 };
1216
1217 static
1218 int lttng_syscall_list_open(struct inode *inode, struct file *file)
1219 {
1220         return seq_open(file, &lttng_syscall_list_seq_ops);
1221 }
1222
1223 const struct file_operations lttng_syscall_list_fops = {
1224         .owner = THIS_MODULE,
1225         .open = lttng_syscall_list_open,
1226         .read = seq_read,
1227         .llseek = seq_lseek,
1228         .release = seq_release,
1229 };
1230
1231 /*
1232  * A syscall is enabled if it is traced for either entry or exit.
1233  */
1234 long lttng_syscall_table_get_active_mask(struct lttng_kernel_syscall_table *syscall_table,
1235                 struct lttng_kernel_abi_syscall_mask __user *usyscall_mask)
1236 {
1237         uint32_t len, sc_tables_len, bitmask_len;
1238         int ret = 0, bit;
1239         char *tmp_mask;
1240         struct lttng_syscall_filter *filter;
1241
1242         ret = get_user(len, &usyscall_mask->len);
1243         if (ret)
1244                 return ret;
1245         sc_tables_len = get_sc_tables_len();
1246         bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
1247         if (len < sc_tables_len) {
1248                 return put_user(sc_tables_len, &usyscall_mask->len);
1249         }
1250         /* Array is large enough, we can copy array to user-space. */
1251         tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
1252         if (!tmp_mask)
1253                 return -ENOMEM;
1254         filter = syscall_table->sc_filter;
1255
1256         for (bit = 0; bit < sc_table.len; bit++) {
1257                 char state;
1258
1259                 if (syscall_table->syscall_dispatch) {
1260                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1261                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1262                                 state = test_bit(bit, filter->sc_entry)
1263                                         || test_bit(bit, filter->sc_exit);
1264                         else
1265                                 state = 1;
1266                 } else {
1267                         state = 0;
1268                 }
1269                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1270         }
1271         for (; bit < sc_tables_len; bit++) {
1272                 char state;
1273
1274                 if (syscall_table->compat_syscall_dispatch) {
1275                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1276                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1277                                 state = test_bit(bit - sc_table.len,
1278                                                 filter->sc_compat_entry)
1279                                         || test_bit(bit - sc_table.len,
1280                                                 filter->sc_compat_exit);
1281                         else
1282                                 state = 1;
1283                 } else {
1284                         state = 0;
1285                 }
1286                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1287         }
1288         if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
1289                 ret = -EFAULT;
1290         kfree(tmp_mask);
1291         return ret;
1292 }
1293
1294 int lttng_abi_syscall_list(void)
1295 {
1296         struct file *syscall_list_file;
1297         int file_fd, ret;
1298
1299         file_fd = get_unused_fd_flags(0);
1300         if (file_fd < 0) {
1301                 ret = file_fd;
1302                 goto fd_error;
1303         }
1304
1305         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
1306                                           &lttng_syscall_list_fops,
1307                                           NULL, O_RDWR);
1308         if (IS_ERR(syscall_list_file)) {
1309                 ret = PTR_ERR(syscall_list_file);
1310                 goto file_error;
1311         }
1312         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
1313         if (ret < 0)
1314                 goto open_error;
1315         fd_install(file_fd, syscall_list_file);
1316         return file_fd;
1317
1318 open_error:
1319         fput(syscall_list_file);
1320 file_error:
1321         put_unused_fd(file_fd);
1322 fd_error:
1323         return ret;
1324 }