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 #include <lttng/kernel-version.h>
  35
  36 #include "lttng-syscalls.h"
  37
  38 #ifndef CONFIG_COMPAT
  39 # ifndef is_compat_task
  40 #  define is_compat_task()      (0)
  41 # endif
  42 #endif
  43
  44 /* in_compat_syscall appears in kernel 4.6. */
  45 #ifndef in_compat_syscall
  46 # define in_compat_syscall()    is_compat_task()
  47 #endif
  48
  49 /* in_x32_syscall appears in kernel 4.7. */
  50 #if (LTTNG_LINUX_VERSION_CODE < LTTNG_KERNEL_VERSION(4,7,0))
  51 # ifdef CONFIG_X86_X32_ABI
  52 #  define in_x32_syscall()      is_x32_task()
  53 # endif
  54 #endif
  55
  56 enum sc_type {
  57         SC_TYPE_ENTRY,
  58         SC_TYPE_EXIT,
  59         SC_TYPE_COMPAT_ENTRY,
  60         SC_TYPE_COMPAT_EXIT,
  61 };
  62
  63 #define SYSCALL_ENTRY_TOK               syscall_entry_
  64 #define COMPAT_SYSCALL_ENTRY_TOK        compat_syscall_entry_
  65 #define SYSCALL_EXIT_TOK                syscall_exit_
  66 #define COMPAT_SYSCALL_EXIT_TOK         compat_syscall_exit_
  67
  68 #define SYSCALL_ENTRY_STR               __stringify(SYSCALL_ENTRY_TOK)
  69 #define COMPAT_SYSCALL_ENTRY_STR        __stringify(COMPAT_SYSCALL_ENTRY_TOK)
  70 #define SYSCALL_EXIT_STR                __stringify(SYSCALL_EXIT_TOK)
  71 #define COMPAT_SYSCALL_EXIT_STR         __stringify(COMPAT_SYSCALL_EXIT_TOK)
  72
  73 void syscall_entry_event_probe(void *__data, struct pt_regs *regs, long id);
  74 void syscall_exit_event_probe(void *__data, struct pt_regs *regs, long ret);
  75
  76 #ifdef IA32_NR_syscalls
  77 #define NR_compat_syscalls IA32_NR_syscalls
  78 #else
  79 #define NR_compat_syscalls NR_syscalls
  80 #endif
  81
  82 /*
  83  * Create LTTng tracepoint probes.
  84  */
  85 #define LTTNG_PACKAGE_BUILD
  86 #define CREATE_TRACE_POINTS
  87 #define TP_MODULE_NOINIT
  88 #define TRACE_INCLUDE_PATH instrumentation/syscalls/headers
  89
  90 #define PARAMS(args...) args
  91
  92 /* Handle unknown syscalls */
  93 #undef TRACE_SYSTEM
  94 #define TRACE_SYSTEM syscalls_unknown
  95 #include <instrumentation/syscalls/headers/syscalls_unknown.h>
  96 #undef TRACE_SYSTEM
  97
  98 #undef TP_PROBE_CB
  99
 100 extern const struct trace_syscall_table sc_table;
 101 extern const struct trace_syscall_table compat_sc_table;
 102
 103 /* Event syscall exit table */
 104 extern const struct trace_syscall_table sc_exit_table;
 105 extern const struct trace_syscall_table compat_sc_exit_table;
 106
 107
 108 #undef SC_EXIT
 109
 110 #undef CREATE_SYSCALL_TABLE
 111
 112 struct lttng_syscall_filter {
 113         DECLARE_BITMAP(sc_entry, NR_syscalls);
 114         DECLARE_BITMAP(sc_exit, NR_syscalls);
 115         DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
 116         DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
 117
 118         /*
 119          * Reference counters keeping track of number of events enabled
 120          * for each bit.
 121          */
 122         u32 sc_entry_refcount_map[NR_syscalls];
 123         u32 sc_exit_refcount_map[NR_syscalls];
 124         u32 sc_compat_entry_refcount_map[NR_compat_syscalls];
 125         u32 sc_compat_exit_refcount_map[NR_compat_syscalls];
 126 };
 127
 128 static void syscall_entry_event_unknown(struct hlist_head *unknown_action_list_head,
 129         struct pt_regs *regs, long id)
 130 {
 131         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 132         struct lttng_kernel_event_common_private *event_priv;
 133
 134         lttng_syscall_get_arguments(current, regs, args);
 135         lttng_hlist_for_each_entry_rcu(event_priv, unknown_action_list_head, u.syscall.node) {
 136                 if (unlikely(in_compat_syscall()))
 137                         __event_probe__compat_syscall_entry_unknown(event_priv->pub, id, args);
 138                 else
 139                         __event_probe__syscall_entry_unknown(event_priv->pub, id, args);
 140         }
 141 }
 142
 143 static __always_inline
 144 void syscall_entry_event_call_func(struct hlist_head *action_list,
 145                 void *func, unsigned int nrargs,
 146                 struct pt_regs *regs)
 147 {
 148         struct lttng_kernel_event_common_private *event_priv;
 149
 150         switch (nrargs) {
 151         case 0:
 152         {
 153                 void (*fptr)(void *__data) = func;
 154
 155                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 156                         fptr(event_priv->pub);
 157                 break;
 158         }
 159         case 1:
 160         {
 161                 void (*fptr)(void *__data, unsigned long arg0) = func;
 162                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 163
 164                 lttng_syscall_get_arguments(current, regs, args);
 165                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 166                         fptr(event_priv->pub, args[0]);
 167                 break;
 168         }
 169         case 2:
 170         {
 171                 void (*fptr)(void *__data,
 172                         unsigned long arg0,
 173                         unsigned long arg1) = func;
 174                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 175
 176                 lttng_syscall_get_arguments(current, regs, args);
 177                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 178                         fptr(event_priv->pub, args[0], args[1]);
 179                 break;
 180         }
 181         case 3:
 182         {
 183                 void (*fptr)(void *__data,
 184                         unsigned long arg0,
 185                         unsigned long arg1,
 186                         unsigned long arg2) = func;
 187                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 188
 189                 lttng_syscall_get_arguments(current, regs, args);
 190                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 191                         fptr(event_priv->pub, args[0], args[1], args[2]);
 192                 break;
 193         }
 194         case 4:
 195         {
 196                 void (*fptr)(void *__data,
 197                         unsigned long arg0,
 198                         unsigned long arg1,
 199                         unsigned long arg2,
 200                         unsigned long arg3) = func;
 201                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 202
 203                 lttng_syscall_get_arguments(current, regs, args);
 204                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 205                         fptr(event_priv->pub, args[0], args[1], args[2], args[3]);
 206                 break;
 207         }
 208         case 5:
 209         {
 210                 void (*fptr)(void *__data,
 211                         unsigned long arg0,
 212                         unsigned long arg1,
 213                         unsigned long arg2,
 214                         unsigned long arg3,
 215                         unsigned long arg4) = func;
 216                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 217
 218                 lttng_syscall_get_arguments(current, regs, args);
 219                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 220                         fptr(event_priv->pub, args[0], args[1], args[2], args[3], args[4]);
 221                 break;
 222         }
 223         case 6:
 224         {
 225                 void (*fptr)(void *__data,
 226                         unsigned long arg0,
 227                         unsigned long arg1,
 228                         unsigned long arg2,
 229                         unsigned long arg3,
 230                         unsigned long arg4,
 231                         unsigned long arg5) = func;
 232                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 233
 234                 lttng_syscall_get_arguments(current, regs, args);
 235                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 236                         fptr(event_priv->pub, args[0], args[1], args[2],
 237                              args[3], args[4], args[5]);
 238                 break;
 239         }
 240         default:
 241                 break;
 242         }
 243 }
 244
 245 void syscall_entry_event_probe(void *__data, struct pt_regs *regs, long id)
 246 {
 247         struct lttng_kernel_syscall_table *syscall_table = __data;
 248         struct hlist_head *action_list, *unknown_action_list;
 249         const struct trace_syscall_entry *table, *entry;
 250         size_t table_len;
 251
 252 #ifdef CONFIG_X86_X32_ABI
 253         if (in_x32_syscall()) {
 254                 /* x32 system calls are not supported. */
 255                 return;
 256         }
 257 #endif
 258         if (unlikely(in_compat_syscall())) {
 259                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 260
 261                 if (id < 0 || id >= NR_compat_syscalls
 262                         || (!READ_ONCE(syscall_table->syscall_all_entry) && !test_bit(id, filter->sc_compat_entry))) {
 263                         /* System call filtered out. */
 264                         return;
 265                 }
 266                 table = compat_sc_table.table;
 267                 table_len = compat_sc_table.len;
 268                 unknown_action_list = &syscall_table->compat_unknown_syscall_dispatch;
 269         } else {
 270                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 271
 272                 if (id < 0 || id >= NR_syscalls
 273                         || (!READ_ONCE(syscall_table->syscall_all_entry) && !test_bit(id, filter->sc_entry))) {
 274                         /* System call filtered out. */
 275                         return;
 276                 }
 277                 table = sc_table.table;
 278                 table_len = sc_table.len;
 279                 unknown_action_list = &syscall_table->unknown_syscall_dispatch;
 280         }
 281         if (unlikely(id < 0 || id >= table_len)) {
 282                 syscall_entry_event_unknown(unknown_action_list, regs, id);
 283                 return;
 284         }
 285
 286         entry = &table[id];
 287         if (!entry->event_func) {
 288                 syscall_entry_event_unknown(unknown_action_list, regs, id);
 289                 return;
 290         }
 291
 292         if (unlikely(in_compat_syscall())) {
 293                 action_list = &syscall_table->compat_syscall_dispatch[id];
 294         } else {
 295                 action_list = &syscall_table->syscall_dispatch[id];
 296         }
 297         if (unlikely(hlist_empty(action_list)))
 298                 return;
 299
 300         syscall_entry_event_call_func(action_list, entry->event_func, entry->nrargs, regs);
 301 }
 302
 303 static void syscall_exit_event_unknown(struct hlist_head *unknown_action_list_head,
 304         struct pt_regs *regs, long id, long ret)
 305 {
 306         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 307         struct lttng_kernel_event_common_private *event_priv;
 308
 309         lttng_syscall_get_arguments(current, regs, args);
 310         lttng_hlist_for_each_entry_rcu(event_priv, unknown_action_list_head, u.syscall.node) {
 311                 if (unlikely(in_compat_syscall()))
 312                         __event_probe__compat_syscall_exit_unknown(event_priv->pub, id, ret,
 313                                 args);
 314                 else
 315                         __event_probe__syscall_exit_unknown(event_priv->pub, id, ret, args);
 316         }
 317 }
 318
 319 static __always_inline
 320 void syscall_exit_event_call_func(struct hlist_head *action_list,
 321                 void *func, unsigned int nrargs,
 322                 struct pt_regs *regs, long ret)
 323 {
 324         struct lttng_kernel_event_common_private *event_priv;
 325
 326         switch (nrargs) {
 327         case 0:
 328         {
 329                 void (*fptr)(void *__data, long ret) = func;
 330
 331                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 332                         fptr(event_priv->pub, ret);
 333                 break;
 334         }
 335         case 1:
 336         {
 337                 void (*fptr)(void *__data,
 338                         long ret,
 339                         unsigned long arg0) = func;
 340                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 341
 342                 lttng_syscall_get_arguments(current, regs, args);
 343                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 344                         fptr(event_priv->pub, ret, args[0]);
 345                 break;
 346         }
 347         case 2:
 348         {
 349                 void (*fptr)(void *__data,
 350                         long ret,
 351                         unsigned long arg0,
 352                         unsigned long arg1) = 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]);
 358                 break;
 359         }
 360         case 3:
 361         {
 362                 void (*fptr)(void *__data,
 363                         long ret,
 364                         unsigned long arg0,
 365                         unsigned long arg1,
 366                         unsigned long arg2) = func;
 367                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 368
 369                 lttng_syscall_get_arguments(current, regs, args);
 370                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 371                         fptr(event_priv->pub, ret, args[0], args[1], args[2]);
 372                 break;
 373         }
 374         case 4:
 375         {
 376                 void (*fptr)(void *__data,
 377                         long ret,
 378                         unsigned long arg0,
 379                         unsigned long arg1,
 380                         unsigned long arg2,
 381                         unsigned long arg3) = func;
 382                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 383
 384                 lttng_syscall_get_arguments(current, regs, args);
 385                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 386                         fptr(event_priv->pub, ret, args[0], args[1], args[2], args[3]);
 387                 break;
 388         }
 389         case 5:
 390         {
 391                 void (*fptr)(void *__data,
 392                         long ret,
 393                         unsigned long arg0,
 394                         unsigned long arg1,
 395                         unsigned long arg2,
 396                         unsigned long arg3,
 397                         unsigned long arg4) = func;
 398                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 399
 400                 lttng_syscall_get_arguments(current, regs, args);
 401                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 402                         fptr(event_priv->pub, ret, args[0], args[1], args[2], args[3], args[4]);
 403                 break;
 404         }
 405         case 6:
 406         {
 407                 void (*fptr)(void *__data,
 408                         long ret,
 409                         unsigned long arg0,
 410                         unsigned long arg1,
 411                         unsigned long arg2,
 412                         unsigned long arg3,
 413                         unsigned long arg4,
 414                         unsigned long arg5) = func;
 415                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 416
 417                 lttng_syscall_get_arguments(current, regs, args);
 418                 lttng_hlist_for_each_entry_rcu(event_priv, action_list, u.syscall.node)
 419                         fptr(event_priv->pub, ret, args[0], args[1], args[2],
 420                              args[3], args[4], args[5]);
 421                 break;
 422         }
 423         default:
 424                 break;
 425         }
 426 }
 427
 428 void syscall_exit_event_probe(void *__data, struct pt_regs *regs, long ret)
 429 {
 430         struct lttng_kernel_syscall_table *syscall_table = __data;
 431         struct hlist_head *action_list, *unknown_action_list;
 432         const struct trace_syscall_entry *table, *entry;
 433         size_t table_len;
 434         long id;
 435
 436 #ifdef CONFIG_X86_X32_ABI
 437         if (in_x32_syscall()) {
 438                 /* x32 system calls are not supported. */
 439                 return;
 440         }
 441 #endif
 442         id = syscall_get_nr(current, regs);
 443
 444         if (unlikely(in_compat_syscall())) {
 445                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 446
 447                 if (id < 0 || id >= NR_compat_syscalls
 448                         || (!READ_ONCE(syscall_table->syscall_all_exit) && !test_bit(id, filter->sc_compat_exit))) {
 449                         /* System call filtered out. */
 450                         return;
 451                 }
 452                 table = compat_sc_exit_table.table;
 453                 table_len = compat_sc_exit_table.len;
 454                 unknown_action_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
 455         } else {
 456                 struct lttng_syscall_filter *filter = syscall_table->sc_filter;
 457
 458                 if (id < 0 || id >= NR_syscalls
 459                         || (!READ_ONCE(syscall_table->syscall_all_exit) && !test_bit(id, filter->sc_exit))) {
 460                         /* System call filtered out. */
 461                         return;
 462                 }
 463                 table = sc_exit_table.table;
 464                 table_len = sc_exit_table.len;
 465                 unknown_action_list = &syscall_table->unknown_syscall_exit_dispatch;
 466         }
 467         if (unlikely(id < 0 || id >= table_len)) {
 468                 syscall_exit_event_unknown(unknown_action_list, regs, id, ret);
 469                 return;
 470         }
 471
 472         entry = &table[id];
 473         if (!entry->event_func) {
 474                 syscall_exit_event_unknown(unknown_action_list, regs, id, ret);
 475                 return;
 476         }
 477
 478         if (unlikely(in_compat_syscall())) {
 479                 action_list = &syscall_table->compat_syscall_exit_dispatch[id];
 480         } else {
 481                 action_list = &syscall_table->syscall_exit_dispatch[id];
 482         }
 483         if (unlikely(hlist_empty(action_list)))
 484                 return;
 485
 486         syscall_exit_event_call_func(action_list, entry->event_func, entry->nrargs,
 487                                regs, ret);
 488 }
 489
 490 static
 491 struct lttng_kernel_syscall_table *get_syscall_table_from_enabler(struct lttng_event_enabler_common *event_enabler)
 492 {
 493         switch (event_enabler->enabler_type) {
 494         case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
 495         {
 496                 struct lttng_event_recorder_enabler *event_recorder_enabler =
 497                         container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
 498                 return &event_recorder_enabler->chan->priv->parent.syscall_table;
 499         }
 500         case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
 501         {
 502                 struct lttng_event_notifier_enabler *event_notifier_enabler =
 503                         container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
 504                 return &event_notifier_enabler->group->syscall_table;
 505         }
 506         default:
 507                 return NULL;
 508         }
 509 }
 510
 511 static
 512 struct lttng_kernel_syscall_table *get_syscall_table_from_event(struct lttng_kernel_event_common *event)
 513 {
 514         switch (event->type) {
 515         case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
 516         {
 517                 struct lttng_kernel_event_recorder *event_recorder =
 518                         container_of(event, struct lttng_kernel_event_recorder, parent);
 519                 return &event_recorder->chan->priv->parent.syscall_table;
 520         }
 521         case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
 522         {
 523                 struct lttng_kernel_event_notifier *event_notifier =
 524                         container_of(event, struct lttng_kernel_event_notifier, parent);
 525                 return &event_notifier->priv->group->syscall_table;
 526         }
 527         default:
 528                 return NULL;
 529         }
 530 }
 531
 532 static
 533 void lttng_syscall_event_enabler_create_event(struct lttng_event_enabler_common *syscall_event_enabler,
 534                 const struct lttng_kernel_event_desc *desc, enum sc_type type, unsigned int syscall_nr)
 535 {
 536         struct lttng_kernel_event_common *event;
 537
 538         switch (syscall_event_enabler->enabler_type) {
 539         case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
 540         {
 541                 struct lttng_event_recorder_enabler *syscall_event_recorder_enabler =
 542                         container_of(syscall_event_enabler, struct lttng_event_recorder_enabler, parent);
 543                 struct lttng_event_recorder_enabler *event_recorder_enabler;
 544                 struct lttng_kernel_abi_event ev;
 545
 546                 /* We need to create an event for this syscall/enabler. */
 547                 memset(&ev, 0, sizeof(ev));
 548                 switch (type) {
 549                 case SC_TYPE_ENTRY:
 550                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 551                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 552                         break;
 553                 case SC_TYPE_EXIT:
 554                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 555                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 556                         break;
 557                 case SC_TYPE_COMPAT_ENTRY:
 558                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 559                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 560                         break;
 561                 case SC_TYPE_COMPAT_EXIT:
 562                         ev.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 563                         ev.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 564                         break;
 565                 }
 566                 strncpy(ev.name, desc->event_name, LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1);
 567                 ev.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 568                 ev.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 569                 event_recorder_enabler = lttng_event_recorder_enabler_create(LTTNG_ENABLER_FORMAT_NAME, &ev,
 570                                 syscall_event_recorder_enabler->chan);
 571                 WARN_ON_ONCE(!event_recorder_enabler);
 572                 if (!event_recorder_enabler)
 573                         return;
 574                 event = _lttng_kernel_event_create(&event_recorder_enabler->parent, desc);
 575                 WARN_ON_ONCE(IS_ERR(event));
 576                 lttng_event_enabler_destroy(&event_recorder_enabler->parent);
 577                 if (IS_ERR(event)) {
 578                         printk(KERN_INFO "Unable to create event recorder %s\n", desc->event_name);
 579                         return;
 580                 }
 581                 event->priv->u.syscall.syscall_id = syscall_nr;
 582                 break;
 583         }
 584         case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
 585         {
 586                 struct lttng_event_notifier_enabler *syscall_event_notifier_enabler =
 587                         container_of(syscall_event_enabler, struct lttng_event_notifier_enabler, parent);
 588                 struct lttng_event_notifier_enabler *event_notifier_enabler;
 589                 struct lttng_kernel_abi_event_notifier event_notifier_param;
 590                 uint64_t user_token = syscall_event_enabler->user_token;
 591                 uint64_t error_counter_index = syscall_event_notifier_enabler->error_counter_index;
 592
 593                 memset(&event_notifier_param, 0, sizeof(event_notifier_param));
 594                 switch (type) {
 595                 case SC_TYPE_ENTRY:
 596                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 597                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 598                         break;
 599                 case SC_TYPE_EXIT:
 600                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 601                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_NATIVE;
 602                         break;
 603                 case SC_TYPE_COMPAT_ENTRY:
 604                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_ENTRY;
 605                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 606                         break;
 607                 case SC_TYPE_COMPAT_EXIT:
 608                         event_notifier_param.event.u.syscall.entryexit = LTTNG_KERNEL_ABI_SYSCALL_EXIT;
 609                         event_notifier_param.event.u.syscall.abi = LTTNG_KERNEL_ABI_SYSCALL_ABI_COMPAT;
 610                         break;
 611                 }
 612                 strncat(event_notifier_param.event.name, desc->event_name,
 613                         LTTNG_KERNEL_ABI_SYM_NAME_LEN - strlen(event_notifier_param.event.name) - 1);
 614                 event_notifier_param.event.name[LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1] = '\0';
 615                 event_notifier_param.event.instrumentation = LTTNG_KERNEL_ABI_SYSCALL;
 616                 event_notifier_param.event.token = user_token;
 617                 event_notifier_param.error_counter_index = error_counter_index;
 618
 619                 event_notifier_enabler = lttng_event_notifier_enabler_create(LTTNG_ENABLER_FORMAT_NAME,
 620                                 &event_notifier_param, syscall_event_notifier_enabler->group);
 621                 WARN_ON_ONCE(!event_notifier_enabler);
 622                 event = _lttng_kernel_event_create(&event_notifier_enabler->parent, desc);
 623                 WARN_ON_ONCE(IS_ERR(event));
 624                 lttng_event_enabler_destroy(&event_notifier_enabler->parent);
 625                 if (IS_ERR(event)) {
 626                         printk(KERN_INFO "Unable to create event notifier %s\n", desc->event_name);
 627                         return;
 628                 }
 629                 event->priv->u.syscall.syscall_id = syscall_nr;
 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 #ifndef CONFIG_COMPAT
 646         if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
 647                 return;
 648 #endif
 649         /* iterate over all syscall and create event that match */
 650         for (i = 0; i < table_len; i++) {
 651                 struct lttng_kernel_event_common_private *event_priv;
 652                 struct hlist_head *head;
 653                 bool found = false;
 654
 655                 desc = table[i].desc;
 656                 if (!desc) {
 657                         /* Unknown syscall */
 658                         continue;
 659                 }
 660
 661                 if (!lttng_desc_match_enabler(desc, syscall_event_enabler_common))
 662                         continue;
 663
 664                 /*
 665                  * Check if already created.
 666                  */
 667                 head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 668                 lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
 669                         if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub)) {
 670                                 found = true;
 671                                 break;
 672                         }
 673                 }
 674                 if (found)
 675                         continue;
 676
 677                 lttng_syscall_event_enabler_create_event(syscall_event_enabler_common, desc, type, i);
 678         }
 679 }
 680
 681 static
 682 bool lttng_syscall_event_enabler_is_wildcard_all(struct lttng_event_enabler_common *event_enabler)
 683 {
 684         if (event_enabler->event_param.instrumentation != LTTNG_KERNEL_ABI_SYSCALL)
 685                 return false;
 686         if (event_enabler->event_param.u.syscall.abi != LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL)
 687                 return false;
 688         if (event_enabler->event_param.u.syscall.match != LTTNG_KERNEL_ABI_SYSCALL_MATCH_NAME)
 689                 return false;
 690         if (strcmp(event_enabler->event_param.name, "*"))
 691                 return false;
 692         return true;
 693 }
 694
 695 static
 696 void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabler, enum sc_type type)
 697 {
 698         struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(event_enabler);
 699         struct lttng_kernel_event_common_private *event_priv;
 700         const struct lttng_kernel_event_desc *desc;
 701         bool found = false;
 702         struct hlist_head *head;
 703
 704 #ifndef CONFIG_COMPAT
 705         if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
 706                 return;
 707 #endif
 708         /*
 709          * Considering that currently system calls can only be enabled on a per
 710          * name basis (or wildcard based on a name), unknown syscall events are
 711          * only used when matching *all* system calls, because this is the only
 712          * case which can be associated with an unknown system call.
 713          *
 714          * When enabling system call on a per system call number basis will be
 715          * supported, this will need to be revisited.
 716          */
 717         if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
 718                 return;
 719
 720         switch (type) {
 721         case SC_TYPE_ENTRY:
 722                 desc = &__event_desc___syscall_entry_unknown;
 723                 break;
 724         case SC_TYPE_EXIT:
 725                 desc = &__event_desc___syscall_exit_unknown;
 726                 break;
 727         case SC_TYPE_COMPAT_ENTRY:
 728                 desc = &__event_desc___compat_syscall_entry_unknown;
 729                 break;
 730         case SC_TYPE_COMPAT_EXIT:
 731                 desc = &__event_desc___compat_syscall_exit_unknown;
 732                 break;
 733         default:
 734                 WARN_ON_ONCE(1);
 735         }
 736
 737         /*
 738          * Check if already created.
 739          */
 740         head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 741         lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
 742                 if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub)) {
 743                         found = true;
 744                         break;
 745                 }
 746         }
 747         if (!found)
 748                 lttng_syscall_event_enabler_create_event(event_enabler, desc, 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_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_tracepoint_probe_register("sys_exit",
 827                                 (void *) syscall_exit_event_probe, syscall_table);
 828                 if (ret) {
 829                         WARN_ON_ONCE(lttng_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 0;
 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_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_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 uint32_t get_sc_tables_len(void)
 878 {
 879         return sc_table.len + compat_sc_table.len;
 880 }
 881
 882 static
 883 const char *get_syscall_name(const char *desc_name,
 884                 enum lttng_syscall_abi abi,
 885                 enum lttng_syscall_entryexit entryexit)
 886 {
 887         size_t prefix_len = 0;
 888
 889
 890         switch (entryexit) {
 891         case LTTNG_SYSCALL_ENTRY:
 892                 switch (abi) {
 893                 case LTTNG_SYSCALL_ABI_NATIVE:
 894                         prefix_len = strlen(SYSCALL_ENTRY_STR);
 895                         break;
 896                 case LTTNG_SYSCALL_ABI_COMPAT:
 897                         prefix_len = strlen(COMPAT_SYSCALL_ENTRY_STR);
 898                         break;
 899                 }
 900                 break;
 901         case LTTNG_SYSCALL_EXIT:
 902                 switch (abi) {
 903                 case LTTNG_SYSCALL_ABI_NATIVE:
 904                         prefix_len = strlen(SYSCALL_EXIT_STR);
 905                         break;
 906                 case LTTNG_SYSCALL_ABI_COMPAT:
 907                         prefix_len = strlen(COMPAT_SYSCALL_EXIT_STR);
 908                         break;
 909                 }
 910                 break;
 911         }
 912         WARN_ON_ONCE(prefix_len == 0);
 913         return desc_name + prefix_len;
 914 }
 915
 916 static
 917 int lttng_syscall_filter_enable(
 918                 struct lttng_syscall_filter *filter,
 919                 const char *desc_name, enum lttng_syscall_abi abi,
 920                 enum lttng_syscall_entryexit entryexit,
 921                 unsigned int syscall_id)
 922 {
 923         const char *syscall_name;
 924         unsigned long *bitmap;
 925         u32 *refcount_map;
 926
 927         syscall_name = get_syscall_name(desc_name, abi, entryexit);
 928
 929         switch (entryexit) {
 930         case LTTNG_SYSCALL_ENTRY:
 931                 switch (abi) {
 932                 case LTTNG_SYSCALL_ABI_NATIVE:
 933                         bitmap = filter->sc_entry;
 934                         refcount_map = filter->sc_entry_refcount_map;
 935                         break;
 936                 case LTTNG_SYSCALL_ABI_COMPAT:
 937                         bitmap = filter->sc_compat_entry;
 938                         refcount_map = filter->sc_compat_entry_refcount_map;
 939                         break;
 940                 default:
 941                         return -EINVAL;
 942                 }
 943                 break;
 944         case LTTNG_SYSCALL_EXIT:
 945                 switch (abi) {
 946                 case LTTNG_SYSCALL_ABI_NATIVE:
 947                         bitmap = filter->sc_exit;
 948                         refcount_map = filter->sc_exit_refcount_map;
 949                         break;
 950                 case LTTNG_SYSCALL_ABI_COMPAT:
 951                         bitmap = filter->sc_compat_exit;
 952                         refcount_map = filter->sc_compat_exit_refcount_map;
 953                         break;
 954                 default:
 955                         return -EINVAL;
 956                 }
 957                 break;
 958         default:
 959                 return -EINVAL;
 960         }
 961         if (refcount_map[syscall_id] == U32_MAX)
 962                 return -EOVERFLOW;
 963         if (refcount_map[syscall_id]++ == 0)
 964                 bitmap_set(bitmap, syscall_id, 1);
 965         return 0;
 966 }
 967
 968 int lttng_syscall_filter_enable_event(struct lttng_kernel_event_common *event)
 969 {
 970         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
 971         unsigned int syscall_id = event->priv->u.syscall.syscall_id;
 972         struct hlist_head *dispatch_list;
 973         int ret = 0;
 974
 975         WARN_ON_ONCE(event->priv->instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
 976
 977         /* Unknown syscall */
 978         if (syscall_id == -1U) {
 979                 switch (event->priv->u.syscall.entryexit) {
 980                 case LTTNG_SYSCALL_ENTRY:
 981                         switch (event->priv->u.syscall.abi) {
 982                         case LTTNG_SYSCALL_ABI_NATIVE:
 983                                 dispatch_list = &syscall_table->unknown_syscall_dispatch;
 984                                 break;
 985                         case LTTNG_SYSCALL_ABI_COMPAT:
 986                                 dispatch_list = &syscall_table->compat_unknown_syscall_dispatch;
 987                                 break;
 988                         default:
 989                                 ret = -EINVAL;
 990                                 goto end;
 991                         }
 992                         break;
 993                 case LTTNG_SYSCALL_EXIT:
 994                         switch (event->priv->u.syscall.abi) {
 995                         case LTTNG_SYSCALL_ABI_NATIVE:
 996                                 dispatch_list = &syscall_table->unknown_syscall_exit_dispatch;
 997                                 break;
 998                         case LTTNG_SYSCALL_ABI_COMPAT:
 999                                 dispatch_list = &syscall_table->compat_unknown_syscall_exit_dispatch;
1000                                 break;
1001                         default:
1002                                 ret = -EINVAL;
1003                                 goto end;
1004                         }
1005                         break;
1006                 default:
1007                         ret = -EINVAL;
1008                         goto end;
1009                 }
1010         } else {
1011                 ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
1012                         event->priv->desc->event_name, event->priv->u.syscall.abi,
1013                         event->priv->u.syscall.entryexit, syscall_id);
1014                 if (ret)
1015                         return ret;
1016
1017                 switch (event->priv->u.syscall.entryexit) {
1018                 case LTTNG_SYSCALL_ENTRY:
1019                         switch (event->priv->u.syscall.abi) {
1020                         case LTTNG_SYSCALL_ABI_NATIVE:
1021                                 dispatch_list = &syscall_table->syscall_dispatch[syscall_id];
1022                                 break;
1023                         case LTTNG_SYSCALL_ABI_COMPAT:
1024                                 dispatch_list = &syscall_table->compat_syscall_dispatch[syscall_id];
1025                                 break;
1026                         default:
1027                                 ret = -EINVAL;
1028                                 goto end;
1029                         }
1030                         break;
1031                 case LTTNG_SYSCALL_EXIT:
1032                         switch (event->priv->u.syscall.abi) {
1033                         case LTTNG_SYSCALL_ABI_NATIVE:
1034                                 dispatch_list = &syscall_table->syscall_exit_dispatch[syscall_id];
1035                                 break;
1036                         case LTTNG_SYSCALL_ABI_COMPAT:
1037                                 dispatch_list = &syscall_table->compat_syscall_exit_dispatch[syscall_id];
1038                                 break;
1039                         default:
1040                                 ret = -EINVAL;
1041                                 goto end;
1042                         }
1043                         break;
1044                 default:
1045                         ret = -EINVAL;
1046                         goto end;
1047                 }
1048         }
1049
1050         hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_list);
1051 end:
1052         return ret;
1053 }
1054
1055 static
1056 int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
1057                 const char *desc_name, enum lttng_syscall_abi abi,
1058                 enum lttng_syscall_entryexit entryexit,
1059                 unsigned int syscall_id)
1060 {
1061         const char *syscall_name;
1062         unsigned long *bitmap;
1063         u32 *refcount_map;
1064
1065         syscall_name = get_syscall_name(desc_name, abi, entryexit);
1066
1067         switch (entryexit) {
1068         case LTTNG_SYSCALL_ENTRY:
1069                 switch (abi) {
1070                 case LTTNG_SYSCALL_ABI_NATIVE:
1071                         bitmap = filter->sc_entry;
1072                         refcount_map = filter->sc_entry_refcount_map;
1073                         break;
1074                 case LTTNG_SYSCALL_ABI_COMPAT:
1075                         bitmap = filter->sc_compat_entry;
1076                         refcount_map = filter->sc_compat_entry_refcount_map;
1077                         break;
1078                 default:
1079                         return -EINVAL;
1080                 }
1081                 break;
1082         case LTTNG_SYSCALL_EXIT:
1083                 switch (abi) {
1084                 case LTTNG_SYSCALL_ABI_NATIVE:
1085                         bitmap = filter->sc_exit;
1086                         refcount_map = filter->sc_exit_refcount_map;
1087                         break;
1088                 case LTTNG_SYSCALL_ABI_COMPAT:
1089                         bitmap = filter->sc_compat_exit;
1090                         refcount_map = filter->sc_compat_exit_refcount_map;
1091                         break;
1092                 default:
1093                         return -EINVAL;
1094                 }
1095                 break;
1096         default:
1097                 return -EINVAL;
1098         }
1099         if (refcount_map[syscall_id] == 0)
1100                 return -ENOENT;
1101         if (--refcount_map[syscall_id] == 0)
1102                 bitmap_clear(bitmap, syscall_id, 1);
1103         return 0;
1104 }
1105
1106 int lttng_syscall_filter_disable_event(struct lttng_kernel_event_common *event)
1107 {
1108         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
1109         unsigned int syscall_id = event->priv->u.syscall.syscall_id;
1110         int ret;
1111
1112         /* Except for unknown syscall */
1113         if (syscall_id != -1U) {
1114                 ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
1115                         event->priv->desc->event_name, event->priv->u.syscall.abi,
1116                         event->priv->u.syscall.entryexit, syscall_id);
1117                 if (ret)
1118                         return ret;
1119         }
1120         hlist_del_rcu(&event->priv->u.syscall.node);
1121         return 0;
1122 }
1123
1124 void lttng_syscall_table_set_wildcard_all(struct lttng_event_enabler_common *event_enabler)
1125 {
1126         struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(event_enabler);
1127         enum lttng_kernel_abi_syscall_entryexit entryexit;
1128         int enabled = event_enabler->enabled;
1129
1130         if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
1131                 return;
1132         entryexit = event_enabler->event_param.u.syscall.entryexit;
1133         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
1134                 WRITE_ONCE(syscall_table->syscall_all_entry, enabled);
1135
1136         if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
1137                 WRITE_ONCE(syscall_table->syscall_all_exit, enabled);
1138 }
1139
1140 static
1141 const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
1142 {
1143         const struct trace_syscall_entry *entry;
1144         int iter = 0;
1145
1146         for (entry = sc_table.table;
1147                         entry < sc_table.table + sc_table.len;
1148                          entry++) {
1149                 if (iter++ >= *pos)
1150                         return entry;
1151         }
1152         for (entry = compat_sc_table.table;
1153                         entry < compat_sc_table.table + compat_sc_table.len;
1154                          entry++) {
1155                 if (iter++ >= *pos)
1156                         return entry;
1157         }
1158         /* End of list */
1159         return NULL;
1160 }
1161
1162 static
1163 void *syscall_list_start(struct seq_file *m, loff_t *pos)
1164 {
1165         return (void *) syscall_list_get_entry(pos);
1166 }
1167
1168 static
1169 void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
1170 {
1171         (*ppos)++;
1172         return (void *) syscall_list_get_entry(ppos);
1173 }
1174
1175 static
1176 void syscall_list_stop(struct seq_file *m, void *p)
1177 {
1178 }
1179
1180 static
1181 int get_sc_table(const struct trace_syscall_entry *entry,
1182                 const struct trace_syscall_entry **table,
1183                 unsigned int *bitness)
1184 {
1185         if (entry >= sc_table.table && entry < sc_table.table + sc_table.len) {
1186                 if (bitness)
1187                         *bitness = BITS_PER_LONG;
1188                 if (table)
1189                         *table = sc_table.table;
1190                 return 0;
1191         }
1192         if (!(entry >= compat_sc_table.table
1193                         && entry < compat_sc_table.table + compat_sc_table.len)) {
1194                 return -EINVAL;
1195         }
1196         if (bitness)
1197                 *bitness = 32;
1198         if (table)
1199                 *table = compat_sc_table.table;
1200         return 0;
1201 }
1202
1203 static
1204 int syscall_list_show(struct seq_file *m, void *p)
1205 {
1206         const struct trace_syscall_entry *table, *entry = p;
1207         unsigned int bitness;
1208         unsigned long index;
1209         int ret;
1210         const char *name;
1211
1212         ret = get_sc_table(entry, &table, &bitness);
1213         if (ret)
1214                 return ret;
1215         if (!entry->desc)
1216                 return 0;
1217         if (table == sc_table.table) {
1218                 index = entry - table;
1219                 name = &entry->desc->event_name[strlen(SYSCALL_ENTRY_STR)];
1220         } else {
1221                 index = (entry - table) + sc_table.len;
1222                 name = &entry->desc->event_name[strlen(COMPAT_SYSCALL_ENTRY_STR)];
1223         }
1224         seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
1225                 index, name, bitness);
1226         return 0;
1227 }
1228
1229 static
1230 const struct seq_operations lttng_syscall_list_seq_ops = {
1231         .start = syscall_list_start,
1232         .next = syscall_list_next,
1233         .stop = syscall_list_stop,
1234         .show = syscall_list_show,
1235 };
1236
1237 static
1238 int lttng_syscall_list_open(struct inode *inode, struct file *file)
1239 {
1240         return seq_open(file, &lttng_syscall_list_seq_ops);
1241 }
1242
1243 const struct file_operations lttng_syscall_list_fops = {
1244         .owner = THIS_MODULE,
1245         .open = lttng_syscall_list_open,
1246         .read = seq_read,
1247         .llseek = seq_lseek,
1248         .release = seq_release,
1249 };
1250
1251 /*
1252  * A syscall is enabled if it is traced for either entry or exit.
1253  */
1254 long lttng_syscall_table_get_active_mask(struct lttng_kernel_syscall_table *syscall_table,
1255                 struct lttng_kernel_abi_syscall_mask __user *usyscall_mask)
1256 {
1257         uint32_t len, sc_tables_len, bitmask_len;
1258         int ret = 0, bit;
1259         char *tmp_mask;
1260         struct lttng_syscall_filter *filter;
1261
1262         ret = get_user(len, &usyscall_mask->len);
1263         if (ret)
1264                 return ret;
1265         sc_tables_len = get_sc_tables_len();
1266         bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
1267         if (len < sc_tables_len) {
1268                 return put_user(sc_tables_len, &usyscall_mask->len);
1269         }
1270         /* Array is large enough, we can copy array to user-space. */
1271         tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
1272         if (!tmp_mask)
1273                 return -ENOMEM;
1274         filter = syscall_table->sc_filter;
1275
1276         for (bit = 0; bit < sc_table.len; bit++) {
1277                 char state;
1278
1279                 if (syscall_table->syscall_dispatch) {
1280                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1281                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1282                                 state = test_bit(bit, filter->sc_entry)
1283                                         || test_bit(bit, filter->sc_exit);
1284                         else
1285                                 state = 1;
1286                 } else {
1287                         state = 0;
1288                 }
1289                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1290         }
1291         for (; bit < sc_tables_len; bit++) {
1292                 char state;
1293
1294                 if (syscall_table->compat_syscall_dispatch) {
1295                         if (!(READ_ONCE(syscall_table->syscall_all_entry)
1296                                         || READ_ONCE(syscall_table->syscall_all_exit)) && filter)
1297                                 state = test_bit(bit - sc_table.len,
1298                                                 filter->sc_compat_entry)
1299                                         || test_bit(bit - sc_table.len,
1300                                                 filter->sc_compat_exit);
1301                         else
1302                                 state = 1;
1303                 } else {
1304                         state = 0;
1305                 }
1306                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1307         }
1308         if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
1309                 ret = -EFAULT;
1310         kfree(tmp_mask);
1311         return ret;
1312 }
1313
1314 int lttng_abi_syscall_list(void)
1315 {
1316         struct file *syscall_list_file;
1317         int file_fd, ret;
1318
1319         file_fd = get_unused_fd_flags(0);
1320         if (file_fd < 0) {
1321                 ret = file_fd;
1322                 goto fd_error;
1323         }
1324
1325         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
1326                                           &lttng_syscall_list_fops,
1327                                           NULL, O_RDWR);
1328         if (IS_ERR(syscall_list_file)) {
1329                 ret = PTR_ERR(syscall_list_file);
1330                 goto file_error;
1331         }
1332         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
1333         if (ret < 0)
1334                 goto open_error;
1335         fd_install(file_fd, syscall_list_file);
1336         return file_fd;
1337
1338 open_error:
1339         fput(syscall_list_file);
1340 file_error:
1341         put_unused_fd(file_fd);
1342 fd_error:
1343         return ret;
1344 }