src/lttng-syscalls.c

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