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
  33 #ifndef CONFIG_COMPAT
  34 # ifndef is_compat_task
  35 #  define is_compat_task()      (0)
  36 # endif
  37 #endif
  38
  39 /* in_compat_syscall appears in kernel 4.6. */
  40 #ifndef in_compat_syscall
  41  #define in_compat_syscall()    is_compat_task()
  42 #endif
  43
  44 enum sc_type {
  45         SC_TYPE_ENTRY,
  46         SC_TYPE_EXIT,
  47         SC_TYPE_COMPAT_ENTRY,
  48         SC_TYPE_COMPAT_EXIT,
  49 };
  50
  51 #define SYSCALL_ENTRY_TOK               syscall_entry_
  52 #define COMPAT_SYSCALL_ENTRY_TOK        compat_syscall_entry_
  53 #define SYSCALL_EXIT_TOK                syscall_exit_
  54 #define COMPAT_SYSCALL_EXIT_TOK         compat_syscall_exit_
  55
  56 #define SYSCALL_ENTRY_STR               __stringify(SYSCALL_ENTRY_TOK)
  57 #define COMPAT_SYSCALL_ENTRY_STR        __stringify(COMPAT_SYSCALL_ENTRY_TOK)
  58 #define SYSCALL_EXIT_STR                __stringify(SYSCALL_EXIT_TOK)
  59 #define COMPAT_SYSCALL_EXIT_STR         __stringify(COMPAT_SYSCALL_EXIT_TOK)
  60
  61 static
  62 void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);
  63 static
  64 void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret);
  65
  66 /*
  67  * Forward declarations for old kernels.
  68  */
  69 struct mmsghdr;
  70 struct rlimit64;
  71 struct oldold_utsname;
  72 struct old_utsname;
  73 struct sel_arg_struct;
  74 struct mmap_arg_struct;
  75 struct file_handle;
  76 struct user_msghdr;
  77
  78 /*
  79  * Forward declaration for kernels >= 5.6
  80  */
  81 struct timex;
  82 struct timeval;
  83 struct itimerval;
  84 struct itimerspec;
  85
  86 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0))
  87 typedef __kernel_old_time_t time_t;
  88 #endif
  89
  90 #ifdef IA32_NR_syscalls
  91 #define NR_compat_syscalls IA32_NR_syscalls
  92 #else
  93 #define NR_compat_syscalls NR_syscalls
  94 #endif
  95
  96 /*
  97  * Create LTTng tracepoint probes.
  98  */
  99 #define LTTNG_PACKAGE_BUILD
 100 #define CREATE_TRACE_POINTS
 101 #define TP_MODULE_NOINIT
 102 #define TRACE_INCLUDE_PATH instrumentation/syscalls/headers
 103
 104 #define PARAMS(args...) args
 105
 106 /* Handle unknown syscalls */
 107 #undef TRACE_SYSTEM
 108 #define TRACE_SYSTEM syscalls_unknown
 109 #include <instrumentation/syscalls/headers/syscalls_unknown.h>
 110 #undef TRACE_SYSTEM
 111
 112 #define SC_ENTER
 113
 114 #undef sc_exit
 115 #define sc_exit(...)
 116 #undef sc_in
 117 #define sc_in(...)      __VA_ARGS__
 118 #undef sc_out
 119 #define sc_out(...)
 120 #undef sc_inout
 121 #define sc_inout(...)   __VA_ARGS__
 122
 123 /* Hijack probe callback for system call enter */
 124 #undef TP_PROBE_CB
 125 #define TP_PROBE_CB(_template)          &syscall_entry_probe
 126 #define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
 127         LTTNG_TRACEPOINT_EVENT(syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
 128                 PARAMS(_fields))
 129 #define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
 130         LTTNG_TRACEPOINT_EVENT_CODE(syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
 131                 PARAMS(_locvar), PARAMS(_code_pre),                             \
 132                 PARAMS(_fields), PARAMS(_code_post))
 133 #define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
 134         LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(syscall_entry_##_name, PARAMS(_fields))
 135 #define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)             \
 136         LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(syscall_entry_##_template, syscall_entry_##_name)
 137 /* Enumerations only defined at first inclusion. */
 138 #define SC_LTTNG_TRACEPOINT_ENUM(_name, _values) \
 139         LTTNG_TRACEPOINT_ENUM(_name, PARAMS(_values))
 140 #undef TRACE_SYSTEM
 141 #define TRACE_SYSTEM syscall_entry_integers
 142 #define TRACE_INCLUDE_FILE syscalls_integers
 143 #include <instrumentation/syscalls/headers/syscalls_integers.h>
 144 #undef TRACE_INCLUDE_FILE
 145 #undef TRACE_SYSTEM
 146 #define TRACE_SYSTEM syscall_entry_pointers
 147 #define TRACE_INCLUDE_FILE syscalls_pointers
 148 #include <instrumentation/syscalls/headers/syscalls_pointers.h>
 149 #undef TRACE_INCLUDE_FILE
 150 #undef TRACE_SYSTEM
 151 #undef SC_LTTNG_TRACEPOINT_ENUM
 152 #undef SC_LTTNG_TRACEPOINT_EVENT_CODE
 153 #undef SC_LTTNG_TRACEPOINT_EVENT
 154 #undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
 155 #undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
 156 #undef TP_PROBE_CB
 157 #undef _TRACE_SYSCALLS_INTEGERS_H
 158 #undef _TRACE_SYSCALLS_POINTERS_H
 159
 160 /* Hijack probe callback for compat system call enter */
 161 #define TP_PROBE_CB(_template)          &syscall_entry_probe
 162 #define LTTNG_SC_COMPAT
 163 #define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
 164         LTTNG_TRACEPOINT_EVENT(compat_syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
 165                 PARAMS(_fields))
 166 #define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
 167         LTTNG_TRACEPOINT_EVENT_CODE(compat_syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
 168                 PARAMS(_locvar), PARAMS(_code_pre), PARAMS(_fields), PARAMS(_code_post))
 169 #define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
 170         LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(compat_syscall_entry_##_name, PARAMS(_fields))
 171 #define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)             \
 172         LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(compat_syscall_entry_##_template, \
 173                 compat_syscall_entry_##_name)
 174 /* Enumerations only defined at inital inclusion (not here). */
 175 #define SC_LTTNG_TRACEPOINT_ENUM(_name, _values)
 176 #define TRACE_SYSTEM compat_syscall_entry_integers
 177 #define TRACE_INCLUDE_FILE compat_syscalls_integers
 178 #include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
 179 #undef TRACE_INCLUDE_FILE
 180 #undef TRACE_SYSTEM
 181 #define TRACE_SYSTEM compat_syscall_entry_pointers
 182 #define TRACE_INCLUDE_FILE compat_syscalls_pointers
 183 #include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
 184 #undef TRACE_INCLUDE_FILE
 185 #undef TRACE_SYSTEM
 186 #undef SC_LTTNG_TRACEPOINT_ENUM
 187 #undef SC_LTTNG_TRACEPOINT_EVENT_CODE
 188 #undef SC_LTTNG_TRACEPOINT_EVENT
 189 #undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
 190 #undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
 191 #undef TP_PROBE_CB
 192 #undef _TRACE_SYSCALLS_INTEGERS_H
 193 #undef _TRACE_SYSCALLS_POINTERS_H
 194 #undef LTTNG_SC_COMPAT
 195
 196 #undef SC_ENTER
 197
 198 #define SC_EXIT
 199
 200 #undef sc_exit
 201 #define sc_exit(...)            __VA_ARGS__
 202 #undef sc_in
 203 #define sc_in(...)
 204 #undef sc_out
 205 #define sc_out(...)             __VA_ARGS__
 206 #undef sc_inout
 207 #define sc_inout(...)           __VA_ARGS__
 208
 209 /* Hijack probe callback for system call exit */
 210 #define TP_PROBE_CB(_template)          &syscall_exit_probe
 211 #define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
 212         LTTNG_TRACEPOINT_EVENT(syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
 213                 PARAMS(_fields))
 214 #define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
 215         LTTNG_TRACEPOINT_EVENT_CODE(syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
 216                 PARAMS(_locvar), PARAMS(_code_pre), PARAMS(_fields), PARAMS(_code_post))
 217 #define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
 218         LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(syscall_exit_##_name, PARAMS(_fields))
 219 #define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)             \
 220         LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(syscall_exit_##_template,        \
 221                 syscall_exit_##_name)
 222 /* Enumerations only defined at inital inclusion (not here). */
 223 #define SC_LTTNG_TRACEPOINT_ENUM(_name, _values)
 224 #define TRACE_SYSTEM syscall_exit_integers
 225 #define TRACE_INCLUDE_FILE syscalls_integers
 226 #include <instrumentation/syscalls/headers/syscalls_integers.h>
 227 #undef TRACE_INCLUDE_FILE
 228 #undef TRACE_SYSTEM
 229 #define TRACE_SYSTEM syscall_exit_pointers
 230 #define TRACE_INCLUDE_FILE syscalls_pointers
 231 #include <instrumentation/syscalls/headers/syscalls_pointers.h>
 232 #undef TRACE_INCLUDE_FILE
 233 #undef TRACE_SYSTEM
 234 #undef SC_LTTNG_TRACEPOINT_ENUM
 235 #undef SC_LTTNG_TRACEPOINT_EVENT_CODE
 236 #undef SC_LTTNG_TRACEPOINT_EVENT
 237 #undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
 238 #undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
 239 #undef TP_PROBE_CB
 240 #undef _TRACE_SYSCALLS_INTEGERS_H
 241 #undef _TRACE_SYSCALLS_POINTERS_H
 242
 243
 244 /* Hijack probe callback for compat system call exit */
 245 #define TP_PROBE_CB(_template)          &syscall_exit_probe
 246 #define LTTNG_SC_COMPAT
 247 #define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
 248         LTTNG_TRACEPOINT_EVENT(compat_syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
 249                 PARAMS(_fields))
 250 #define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
 251         LTTNG_TRACEPOINT_EVENT_CODE(compat_syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
 252                 PARAMS(_locvar), PARAMS(_code_pre), PARAMS(_fields), PARAMS(_code_post))
 253 #define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
 254         LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(compat_syscall_exit_##_name, PARAMS(_fields))
 255 #define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)             \
 256         LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(compat_syscall_exit_##_template, \
 257                 compat_syscall_exit_##_name)
 258 /* Enumerations only defined at inital inclusion (not here). */
 259 #define SC_LTTNG_TRACEPOINT_ENUM(_name, _values)
 260 #define TRACE_SYSTEM compat_syscall_exit_integers
 261 #define TRACE_INCLUDE_FILE compat_syscalls_integers
 262 #include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
 263 #undef TRACE_INCLUDE_FILE
 264 #undef TRACE_SYSTEM
 265 #define TRACE_SYSTEM compat_syscall_exit_pointers
 266 #define TRACE_INCLUDE_FILE compat_syscalls_pointers
 267 #include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
 268 #undef TRACE_INCLUDE_FILE
 269 #undef TRACE_SYSTEM
 270 #undef SC_LTTNG_TRACEPOINT_ENUM
 271 #undef SC_LTTNG_TRACEPOINT_EVENT_CODE
 272 #undef SC_LTTNG_TRACEPOINT_EVENT
 273 #undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
 274 #undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
 275 #undef TP_PROBE_CB
 276 #undef _TRACE_SYSCALLS_INTEGERS_H
 277 #undef _TRACE_SYSCALLS_POINTERS_H
 278 #undef LTTNG_SC_COMPAT
 279
 280 #undef SC_EXIT
 281
 282 #undef TP_MODULE_NOINIT
 283 #undef LTTNG_PACKAGE_BUILD
 284 #undef CREATE_TRACE_POINTS
 285
 286 struct trace_syscall_entry {
 287         void *func;
 288         const struct lttng_event_desc *desc;
 289         const struct lttng_event_field *fields;
 290         unsigned int nrargs;
 291 };
 292
 293 #define CREATE_SYSCALL_TABLE
 294
 295 #define SC_ENTER
 296
 297 #undef sc_exit
 298 #define sc_exit(...)
 299
 300 #undef TRACE_SYSCALL_TABLE
 301 #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)     \
 302         [ _nr ] = {                                             \
 303                 .func = __event_probe__syscall_entry_##_template, \
 304                 .nrargs = (_nrargs),                            \
 305                 .fields = __event_fields___syscall_entry_##_template, \
 306                 .desc = &__event_desc___syscall_entry_##_name,  \
 307         },
 308
 309 /* Syscall enter tracing table */
 310 static const struct trace_syscall_entry sc_table[] = {
 311 #include <instrumentation/syscalls/headers/syscalls_integers.h>
 312 #include <instrumentation/syscalls/headers/syscalls_pointers.h>
 313 };
 314
 315 #undef TRACE_SYSCALL_TABLE
 316 #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)     \
 317         [ _nr ] = {                                             \
 318                 .func = __event_probe__compat_syscall_entry_##_template, \
 319                 .nrargs = (_nrargs),                            \
 320                 .fields = __event_fields___compat_syscall_entry_##_template, \
 321                 .desc = &__event_desc___compat_syscall_entry_##_name, \
 322         },
 323
 324 /* Compat syscall enter table */
 325 const struct trace_syscall_entry compat_sc_table[] = {
 326 #include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
 327 #include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
 328 };
 329
 330 #undef SC_ENTER
 331
 332 #define SC_EXIT
 333
 334 #undef sc_exit
 335 #define sc_exit(...)            __VA_ARGS__
 336
 337 #undef TRACE_SYSCALL_TABLE
 338 #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)     \
 339         [ _nr ] = {                                             \
 340                 .func = __event_probe__syscall_exit_##_template, \
 341                 .nrargs = (_nrargs),                            \
 342                 .fields = __event_fields___syscall_exit_##_template, \
 343                 .desc = &__event_desc___syscall_exit_##_name, \
 344         },
 345
 346 /* Syscall exit table */
 347 static const struct trace_syscall_entry sc_exit_table[] = {
 348 #include <instrumentation/syscalls/headers/syscalls_integers.h>
 349 #include <instrumentation/syscalls/headers/syscalls_pointers.h>
 350 };
 351
 352 #undef TRACE_SYSCALL_TABLE
 353 #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)     \
 354         [ _nr ] = {                                             \
 355                 .func = __event_probe__compat_syscall_exit_##_template, \
 356                 .nrargs = (_nrargs),                            \
 357                 .fields = __event_fields___compat_syscall_exit_##_template, \
 358                 .desc = &__event_desc___compat_syscall_exit_##_name, \
 359         },
 360
 361 /* Compat syscall exit table */
 362 const struct trace_syscall_entry compat_sc_exit_table[] = {
 363 #include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
 364 #include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
 365 };
 366
 367 #undef SC_EXIT
 368
 369 #undef CREATE_SYSCALL_TABLE
 370
 371 struct lttng_syscall_filter {
 372         DECLARE_BITMAP(sc_entry, NR_syscalls);
 373         DECLARE_BITMAP(sc_exit, NR_syscalls);
 374         DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
 375         DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
 376 };
 377
 378 static void syscall_entry_unknown(struct lttng_event *event,
 379         struct pt_regs *regs, unsigned int id)
 380 {
 381         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 382
 383         lttng_syscall_get_arguments(current, regs, args);
 384         if (unlikely(in_compat_syscall()))
 385                 __event_probe__compat_syscall_entry_unknown(event, id, args);
 386         else
 387                 __event_probe__syscall_entry_unknown(event, id, args);
 388 }
 389
 390 void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
 391 {
 392         struct lttng_channel *chan = __data;
 393         struct lttng_event *event, *unknown_event;
 394         const struct trace_syscall_entry *table, *entry;
 395         size_t table_len;
 396
 397         if (unlikely(in_compat_syscall())) {
 398                 struct lttng_syscall_filter *filter = chan->sc_filter;
 399
 400                 if (id < 0 || id >= NR_compat_syscalls
 401                         || (!READ_ONCE(chan->syscall_all) && !test_bit(id, filter->sc_compat_entry))) {
 402                         /* System call filtered out. */
 403                         return;
 404                 }
 405                 table = compat_sc_table;
 406                 table_len = ARRAY_SIZE(compat_sc_table);
 407                 unknown_event = chan->sc_compat_unknown;
 408         } else {
 409                 struct lttng_syscall_filter *filter = chan->sc_filter;
 410
 411                 if (id < 0 || id >= NR_syscalls
 412                         || (!READ_ONCE(chan->syscall_all) && !test_bit(id, filter->sc_entry))) {
 413                         /* System call filtered out. */
 414                         return;
 415                 }
 416                 table = sc_table;
 417                 table_len = ARRAY_SIZE(sc_table);
 418                 unknown_event = chan->sc_unknown;
 419         }
 420         if (unlikely(id < 0 || id >= table_len)) {
 421                 syscall_entry_unknown(unknown_event, regs, id);
 422                 return;
 423         }
 424         if (unlikely(in_compat_syscall()))
 425                 event = chan->compat_sc_table[id];
 426         else
 427                 event = chan->sc_table[id];
 428         if (unlikely(!event)) {
 429                 syscall_entry_unknown(unknown_event, regs, id);
 430                 return;
 431         }
 432         entry = &table[id];
 433         WARN_ON_ONCE(!entry);
 434
 435         switch (entry->nrargs) {
 436         case 0:
 437         {
 438                 void (*fptr)(void *__data) = entry->func;
 439
 440                 fptr(event);
 441                 break;
 442         }
 443         case 1:
 444         {
 445                 void (*fptr)(void *__data, unsigned long arg0) = entry->func;
 446                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 447
 448                 lttng_syscall_get_arguments(current, regs, args);
 449                 fptr(event, args[0]);
 450                 break;
 451         }
 452         case 2:
 453         {
 454                 void (*fptr)(void *__data,
 455                         unsigned long arg0,
 456                         unsigned long arg1) = entry->func;
 457                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 458
 459                 lttng_syscall_get_arguments(current, regs, args);
 460                 fptr(event, args[0], args[1]);
 461                 break;
 462         }
 463         case 3:
 464         {
 465                 void (*fptr)(void *__data,
 466                         unsigned long arg0,
 467                         unsigned long arg1,
 468                         unsigned long arg2) = entry->func;
 469                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 470
 471                 lttng_syscall_get_arguments(current, regs, args);
 472                 fptr(event, args[0], args[1], args[2]);
 473                 break;
 474         }
 475         case 4:
 476         {
 477                 void (*fptr)(void *__data,
 478                         unsigned long arg0,
 479                         unsigned long arg1,
 480                         unsigned long arg2,
 481                         unsigned long arg3) = entry->func;
 482                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 483
 484                 lttng_syscall_get_arguments(current, regs, args);
 485                 fptr(event, args[0], args[1], args[2], args[3]);
 486                 break;
 487         }
 488         case 5:
 489         {
 490                 void (*fptr)(void *__data,
 491                         unsigned long arg0,
 492                         unsigned long arg1,
 493                         unsigned long arg2,
 494                         unsigned long arg3,
 495                         unsigned long arg4) = entry->func;
 496                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 497
 498                 lttng_syscall_get_arguments(current, regs, args);
 499                 fptr(event, args[0], args[1], args[2], args[3], args[4]);
 500                 break;
 501         }
 502         case 6:
 503         {
 504                 void (*fptr)(void *__data,
 505                         unsigned long arg0,
 506                         unsigned long arg1,
 507                         unsigned long arg2,
 508                         unsigned long arg3,
 509                         unsigned long arg4,
 510                         unsigned long arg5) = entry->func;
 511                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 512
 513                 lttng_syscall_get_arguments(current, regs, args);
 514                 fptr(event, args[0], args[1], args[2],
 515                         args[3], args[4], args[5]);
 516                 break;
 517         }
 518         default:
 519                 break;
 520         }
 521 }
 522
 523 static void syscall_exit_unknown(struct lttng_event *event,
 524         struct pt_regs *regs, int id, long ret)
 525 {
 526         unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 527
 528         lttng_syscall_get_arguments(current, regs, args);
 529         if (unlikely(in_compat_syscall()))
 530                 __event_probe__compat_syscall_exit_unknown(event, id, ret,
 531                         args);
 532         else
 533                 __event_probe__syscall_exit_unknown(event, id, ret, args);
 534 }
 535
 536 void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret)
 537 {
 538         struct lttng_channel *chan = __data;
 539         struct lttng_event *event, *unknown_event;
 540         const struct trace_syscall_entry *table, *entry;
 541         size_t table_len;
 542         long id;
 543
 544         id = syscall_get_nr(current, regs);
 545         if (unlikely(in_compat_syscall())) {
 546                 struct lttng_syscall_filter *filter = chan->sc_filter;
 547
 548                 if (id < 0 || id >= NR_compat_syscalls
 549                         || (!READ_ONCE(chan->syscall_all) && !test_bit(id, filter->sc_compat_exit))) {
 550                         /* System call filtered out. */
 551                         return;
 552                 }
 553                 table = compat_sc_exit_table;
 554                 table_len = ARRAY_SIZE(compat_sc_exit_table);
 555                 unknown_event = chan->compat_sc_exit_unknown;
 556         } else {
 557                 struct lttng_syscall_filter *filter = chan->sc_filter;
 558
 559                 if (id < 0 || id >= NR_syscalls
 560                         || (!READ_ONCE(chan->syscall_all) && !test_bit(id, filter->sc_exit))) {
 561                         /* System call filtered out. */
 562                         return;
 563                 }
 564                 table = sc_exit_table;
 565                 table_len = ARRAY_SIZE(sc_exit_table);
 566                 unknown_event = chan->sc_exit_unknown;
 567         }
 568         if (unlikely(id < 0 || id >= table_len)) {
 569                 syscall_exit_unknown(unknown_event, regs, id, ret);
 570                 return;
 571         }
 572         if (unlikely(in_compat_syscall()))
 573                 event = chan->compat_sc_exit_table[id];
 574         else
 575                 event = chan->sc_exit_table[id];
 576         if (unlikely(!event)) {
 577                 syscall_exit_unknown(unknown_event, regs, id, ret);
 578                 return;
 579         }
 580         entry = &table[id];
 581         WARN_ON_ONCE(!entry);
 582
 583         switch (entry->nrargs) {
 584         case 0:
 585         {
 586                 void (*fptr)(void *__data, long ret) = entry->func;
 587
 588                 fptr(event, ret);
 589                 break;
 590         }
 591         case 1:
 592         {
 593                 void (*fptr)(void *__data,
 594                         long ret,
 595                         unsigned long arg0) = entry->func;
 596                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 597
 598                 lttng_syscall_get_arguments(current, regs, args);
 599                 fptr(event, ret, args[0]);
 600                 break;
 601         }
 602         case 2:
 603         {
 604                 void (*fptr)(void *__data,
 605                         long ret,
 606                         unsigned long arg0,
 607                         unsigned long arg1) = entry->func;
 608                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 609
 610                 lttng_syscall_get_arguments(current, regs, args);
 611                 fptr(event, ret, args[0], args[1]);
 612                 break;
 613         }
 614         case 3:
 615         {
 616                 void (*fptr)(void *__data,
 617                         long ret,
 618                         unsigned long arg0,
 619                         unsigned long arg1,
 620                         unsigned long arg2) = entry->func;
 621                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 622
 623                 lttng_syscall_get_arguments(current, regs, args);
 624                 fptr(event, ret, args[0], args[1], args[2]);
 625                 break;
 626         }
 627         case 4:
 628         {
 629                 void (*fptr)(void *__data,
 630                         long ret,
 631                         unsigned long arg0,
 632                         unsigned long arg1,
 633                         unsigned long arg2,
 634                         unsigned long arg3) = entry->func;
 635                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 636
 637                 lttng_syscall_get_arguments(current, regs, args);
 638                 fptr(event, ret, args[0], args[1], args[2], args[3]);
 639                 break;
 640         }
 641         case 5:
 642         {
 643                 void (*fptr)(void *__data,
 644                         long ret,
 645                         unsigned long arg0,
 646                         unsigned long arg1,
 647                         unsigned long arg2,
 648                         unsigned long arg3,
 649                         unsigned long arg4) = entry->func;
 650                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 651
 652                 lttng_syscall_get_arguments(current, regs, args);
 653                 fptr(event, ret, args[0], args[1], args[2], args[3], args[4]);
 654                 break;
 655         }
 656         case 6:
 657         {
 658                 void (*fptr)(void *__data,
 659                         long ret,
 660                         unsigned long arg0,
 661                         unsigned long arg1,
 662                         unsigned long arg2,
 663                         unsigned long arg3,
 664                         unsigned long arg4,
 665                         unsigned long arg5) = entry->func;
 666                 unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 667
 668                 lttng_syscall_get_arguments(current, regs, args);
 669                 fptr(event, ret, args[0], args[1], args[2],
 670                         args[3], args[4], args[5]);
 671                 break;
 672         }
 673         default:
 674                 break;
 675         }
 676 }
 677
 678 /*
 679  * noinline to diminish caller stack size.
 680  * Should be called with sessions lock held.
 681  */
 682 static
 683 int fill_table(const struct trace_syscall_entry *table, size_t table_len,
 684         struct lttng_event **chan_table, struct lttng_channel *chan,
 685         void *filter, enum sc_type type)
 686 {
 687         const struct lttng_event_desc *desc;
 688         unsigned int i;
 689
 690         /* Allocate events for each syscall, insert into table */
 691         for (i = 0; i < table_len; i++) {
 692                 struct lttng_kernel_event ev;
 693                 desc = table[i].desc;
 694
 695                 if (!desc) {
 696                         /* Unknown syscall */
 697                         continue;
 698                 }
 699                 /*
 700                  * Skip those already populated by previous failed
 701                  * register for this channel.
 702                  */
 703                 if (chan_table[i])
 704                         continue;
 705                 memset(&ev, 0, sizeof(ev));
 706                 switch (type) {
 707                 case SC_TYPE_ENTRY:
 708                         ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_ENTRY;
 709                         ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_NATIVE;
 710                         break;
 711                 case SC_TYPE_EXIT:
 712                         ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_EXIT;
 713                         ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_NATIVE;
 714                         break;
 715                 case SC_TYPE_COMPAT_ENTRY:
 716                         ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_ENTRY;
 717                         ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_COMPAT;
 718                         break;
 719                 case SC_TYPE_COMPAT_EXIT:
 720                         ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_EXIT;
 721                         ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_COMPAT;
 722                         break;
 723                 }
 724                 strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
 725                 ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 726                 ev.instrumentation = LTTNG_KERNEL_SYSCALL;
 727                 chan_table[i] = _lttng_event_create(chan, &ev, filter,
 728                                                 desc, ev.instrumentation);
 729                 WARN_ON_ONCE(!chan_table[i]);
 730                 if (IS_ERR(chan_table[i])) {
 731                         /*
 732                          * If something goes wrong in event registration
 733                          * after the first one, we have no choice but to
 734                          * leave the previous events in there, until
 735                          * deleted by session teardown.
 736                          */
 737                         return PTR_ERR(chan_table[i]);
 738                 }
 739         }
 740         return 0;
 741 }
 742
 743 /*
 744  * Should be called with sessions lock held.
 745  */
 746 int lttng_syscalls_register(struct lttng_channel *chan, void *filter)
 747 {
 748         struct lttng_kernel_event ev;
 749         int ret;
 750
 751         wrapper_vmalloc_sync_mappings();
 752
 753         if (!chan->sc_table) {
 754                 /* create syscall table mapping syscall to events */
 755                 chan->sc_table = kzalloc(sizeof(struct lttng_event *)
 756                                         * ARRAY_SIZE(sc_table), GFP_KERNEL);
 757                 if (!chan->sc_table)
 758                         return -ENOMEM;
 759         }
 760         if (!chan->sc_exit_table) {
 761                 /* create syscall table mapping syscall to events */
 762                 chan->sc_exit_table = kzalloc(sizeof(struct lttng_event *)
 763                                         * ARRAY_SIZE(sc_exit_table), GFP_KERNEL);
 764                 if (!chan->sc_exit_table)
 765                         return -ENOMEM;
 766         }
 767
 768
 769 #ifdef CONFIG_COMPAT
 770         if (!chan->compat_sc_table) {
 771                 /* create syscall table mapping compat syscall to events */
 772                 chan->compat_sc_table = kzalloc(sizeof(struct lttng_event *)
 773                                         * ARRAY_SIZE(compat_sc_table), GFP_KERNEL);
 774                 if (!chan->compat_sc_table)
 775                         return -ENOMEM;
 776         }
 777
 778         if (!chan->compat_sc_exit_table) {
 779                 /* create syscall table mapping compat syscall to events */
 780                 chan->compat_sc_exit_table = kzalloc(sizeof(struct lttng_event *)
 781                                         * ARRAY_SIZE(compat_sc_exit_table), GFP_KERNEL);
 782                 if (!chan->compat_sc_exit_table)
 783                         return -ENOMEM;
 784         }
 785 #endif
 786         if (!chan->sc_unknown) {
 787                 const struct lttng_event_desc *desc =
 788                         &__event_desc___syscall_entry_unknown;
 789
 790                 memset(&ev, 0, sizeof(ev));
 791                 strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
 792                 ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 793                 ev.instrumentation = LTTNG_KERNEL_SYSCALL;
 794                 ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_ENTRY;
 795                 ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_NATIVE;
 796                 chan->sc_unknown = _lttng_event_create(chan, &ev, filter,
 797                                                 desc,
 798                                                 ev.instrumentation);
 799                 WARN_ON_ONCE(!chan->sc_unknown);
 800                 if (IS_ERR(chan->sc_unknown)) {
 801                         return PTR_ERR(chan->sc_unknown);
 802                 }
 803         }
 804
 805         if (!chan->sc_compat_unknown) {
 806                 const struct lttng_event_desc *desc =
 807                         &__event_desc___compat_syscall_entry_unknown;
 808
 809                 memset(&ev, 0, sizeof(ev));
 810                 strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
 811                 ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 812                 ev.instrumentation = LTTNG_KERNEL_SYSCALL;
 813                 ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_ENTRY;
 814                 ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_COMPAT;
 815                 chan->sc_compat_unknown = _lttng_event_create(chan, &ev, filter,
 816                                                 desc,
 817                                                 ev.instrumentation);
 818                 WARN_ON_ONCE(!chan->sc_unknown);
 819                 if (IS_ERR(chan->sc_compat_unknown)) {
 820                         return PTR_ERR(chan->sc_compat_unknown);
 821                 }
 822         }
 823
 824         if (!chan->compat_sc_exit_unknown) {
 825                 const struct lttng_event_desc *desc =
 826                         &__event_desc___compat_syscall_exit_unknown;
 827
 828                 memset(&ev, 0, sizeof(ev));
 829                 strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
 830                 ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 831                 ev.instrumentation = LTTNG_KERNEL_SYSCALL;
 832                 ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_EXIT;
 833                 ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_COMPAT;
 834                 chan->compat_sc_exit_unknown = _lttng_event_create(chan, &ev,
 835                                                 filter, desc,
 836                                                 ev.instrumentation);
 837                 WARN_ON_ONCE(!chan->compat_sc_exit_unknown);
 838                 if (IS_ERR(chan->compat_sc_exit_unknown)) {
 839                         return PTR_ERR(chan->compat_sc_exit_unknown);
 840                 }
 841         }
 842
 843         if (!chan->sc_exit_unknown) {
 844                 const struct lttng_event_desc *desc =
 845                         &__event_desc___syscall_exit_unknown;
 846
 847                 memset(&ev, 0, sizeof(ev));
 848                 strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
 849                 ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 850                 ev.instrumentation = LTTNG_KERNEL_SYSCALL;
 851                 ev.u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_EXIT;
 852                 ev.u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_NATIVE;
 853                 chan->sc_exit_unknown = _lttng_event_create(chan, &ev, filter,
 854                                                 desc, ev.instrumentation);
 855                 WARN_ON_ONCE(!chan->sc_exit_unknown);
 856                 if (IS_ERR(chan->sc_exit_unknown)) {
 857                         return PTR_ERR(chan->sc_exit_unknown);
 858                 }
 859         }
 860
 861         ret = fill_table(sc_table, ARRAY_SIZE(sc_table),
 862                         chan->sc_table, chan, filter, SC_TYPE_ENTRY);
 863         if (ret)
 864                 return ret;
 865         ret = fill_table(sc_exit_table, ARRAY_SIZE(sc_exit_table),
 866                         chan->sc_exit_table, chan, filter, SC_TYPE_EXIT);
 867         if (ret)
 868                 return ret;
 869
 870 #ifdef CONFIG_COMPAT
 871         ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table),
 872                         chan->compat_sc_table, chan, filter,
 873                         SC_TYPE_COMPAT_ENTRY);
 874         if (ret)
 875                 return ret;
 876         ret = fill_table(compat_sc_exit_table, ARRAY_SIZE(compat_sc_exit_table),
 877                         chan->compat_sc_exit_table, chan, filter,
 878                         SC_TYPE_COMPAT_EXIT);
 879         if (ret)
 880                 return ret;
 881 #endif
 882
 883         if (!chan->sc_filter) {
 884                 chan->sc_filter = kzalloc(sizeof(struct lttng_syscall_filter),
 885                                 GFP_KERNEL);
 886                 if (!chan->sc_filter)
 887                         return -ENOMEM;
 888         }
 889
 890         if (!chan->sys_enter_registered) {
 891                 ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
 892                                 (void *) syscall_entry_probe, chan);
 893                 if (ret)
 894                         return ret;
 895                 chan->sys_enter_registered = 1;
 896         }
 897         /*
 898          * We change the name of sys_exit tracepoint due to namespace
 899          * conflict with sys_exit syscall entry.
 900          */
 901         if (!chan->sys_exit_registered) {
 902                 ret = lttng_wrapper_tracepoint_probe_register("sys_exit",
 903                                 (void *) syscall_exit_probe, chan);
 904                 if (ret) {
 905                         WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 906                                 (void *) syscall_entry_probe, chan));
 907                         return ret;
 908                 }
 909                 chan->sys_exit_registered = 1;
 910         }
 911         return ret;
 912 }
 913
 914 /*
 915  * Only called at session destruction.
 916  */
 917 int lttng_syscalls_unregister(struct lttng_channel *chan)
 918 {
 919         int ret;
 920
 921         if (!chan->sc_table)
 922                 return 0;
 923         if (chan->sys_enter_registered) {
 924                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
 925                                 (void *) syscall_entry_probe, chan);
 926                 if (ret)
 927                         return ret;
 928                 chan->sys_enter_registered = 0;
 929         }
 930         if (chan->sys_exit_registered) {
 931                 ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
 932                                 (void *) syscall_exit_probe, chan);
 933                 if (ret)
 934                         return ret;
 935                 chan->sys_exit_registered = 0;
 936         }
 937         return 0;
 938 }
 939
 940 int lttng_syscalls_destroy(struct lttng_channel *chan)
 941 {
 942         kfree(chan->sc_table);
 943         kfree(chan->sc_exit_table);
 944 #ifdef CONFIG_COMPAT
 945         kfree(chan->compat_sc_table);
 946         kfree(chan->compat_sc_exit_table);
 947 #endif
 948         kfree(chan->sc_filter);
 949         return 0;
 950 }
 951
 952 static
 953 int get_syscall_nr(const char *syscall_name)
 954 {
 955         int syscall_nr = -1;
 956         int i;
 957
 958         for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
 959                 const struct trace_syscall_entry *entry;
 960                 const char *it_name;
 961
 962                 entry = &sc_table[i];
 963                 if (!entry->desc)
 964                         continue;
 965                 it_name = entry->desc->name;
 966                 it_name += strlen(SYSCALL_ENTRY_STR);
 967                 if (!strcmp(syscall_name, it_name)) {
 968                         syscall_nr = i;
 969                         break;
 970                 }
 971         }
 972         return syscall_nr;
 973 }
 974
 975 static
 976 int get_compat_syscall_nr(const char *syscall_name)
 977 {
 978         int syscall_nr = -1;
 979         int i;
 980
 981         for (i = 0; i < ARRAY_SIZE(compat_sc_table); i++) {
 982                 const struct trace_syscall_entry *entry;
 983                 const char *it_name;
 984
 985                 entry = &compat_sc_table[i];
 986                 if (!entry->desc)
 987                         continue;
 988                 it_name = entry->desc->name;
 989                 it_name += strlen(COMPAT_SYSCALL_ENTRY_STR);
 990                 if (!strcmp(syscall_name, it_name)) {
 991                         syscall_nr = i;
 992                         break;
 993                 }
 994         }
 995         return syscall_nr;
 996 }
 997
 998 static
 999 uint32_t get_sc_tables_len(void)
1000 {
1001         return ARRAY_SIZE(sc_table) + ARRAY_SIZE(compat_sc_table);
1002 }
1003
1004 static
1005 const char *get_syscall_name(struct lttng_event *event)
1006 {
1007         size_t prefix_len = 0;
1008
1009         WARN_ON_ONCE(event->instrumentation != LTTNG_KERNEL_SYSCALL);
1010
1011         switch (event->u.syscall.entryexit) {
1012         case LTTNG_SYSCALL_ENTRY:
1013                 switch (event->u.syscall.abi) {
1014                 case LTTNG_SYSCALL_ABI_NATIVE:
1015                         prefix_len = strlen(SYSCALL_ENTRY_STR);
1016                         break;
1017                 case LTTNG_SYSCALL_ABI_COMPAT:
1018                         prefix_len = strlen(COMPAT_SYSCALL_ENTRY_STR);
1019                         break;
1020                 }
1021                 break;
1022         case LTTNG_SYSCALL_EXIT:
1023                 switch (event->u.syscall.abi) {
1024                 case LTTNG_SYSCALL_ABI_NATIVE:
1025                         prefix_len = strlen(SYSCALL_EXIT_STR);
1026                         break;
1027                 case LTTNG_SYSCALL_ABI_COMPAT:
1028                         prefix_len = strlen(COMPAT_SYSCALL_EXIT_STR);
1029                         break;
1030                 }
1031                 break;
1032         }
1033         WARN_ON_ONCE(prefix_len == 0);
1034         return event->desc->name + prefix_len;
1035 }
1036
1037 int lttng_syscall_filter_enable(struct lttng_channel *chan,
1038                 struct lttng_event *event)
1039 {
1040         struct lttng_syscall_filter *filter = chan->sc_filter;
1041         const char *syscall_name;
1042         unsigned long *bitmap;
1043         int syscall_nr;
1044
1045         WARN_ON_ONCE(!chan->sc_table);
1046
1047         syscall_name = get_syscall_name(event);
1048
1049         switch (event->u.syscall.abi) {
1050         case LTTNG_SYSCALL_ABI_NATIVE:
1051                 syscall_nr = get_syscall_nr(syscall_name);
1052                 break;
1053         case LTTNG_SYSCALL_ABI_COMPAT:
1054                 syscall_nr = get_compat_syscall_nr(syscall_name);
1055                 break;
1056         default:
1057                 return -EINVAL;
1058         }
1059         if (syscall_nr < 0)
1060                 return -ENOENT;
1061
1062
1063         switch (event->u.syscall.entryexit) {
1064         case LTTNG_SYSCALL_ENTRY:
1065                 switch (event->u.syscall.abi) {
1066                 case LTTNG_SYSCALL_ABI_NATIVE:
1067                         bitmap = filter->sc_entry;
1068                         break;
1069                 case LTTNG_SYSCALL_ABI_COMPAT:
1070                         bitmap = filter->sc_compat_entry;
1071                         break;
1072                 }
1073                 break;
1074         case LTTNG_SYSCALL_EXIT:
1075                 switch (event->u.syscall.abi) {
1076                 case LTTNG_SYSCALL_ABI_NATIVE:
1077                         bitmap = filter->sc_exit;
1078                         break;
1079                 case LTTNG_SYSCALL_ABI_COMPAT:
1080                         bitmap = filter->sc_compat_exit;
1081                         break;
1082                 }
1083                 break;
1084         default:
1085                 return -EINVAL;
1086         }
1087         if (test_bit(syscall_nr, bitmap))
1088                 return -EEXIST;
1089         bitmap_set(bitmap, syscall_nr, 1);
1090         return 0;
1091 }
1092
1093 int lttng_syscall_filter_disable(struct lttng_channel *chan,
1094                 struct lttng_event *event)
1095 {
1096         struct lttng_syscall_filter *filter = chan->sc_filter;
1097         const char *syscall_name;
1098         unsigned long *bitmap;
1099         int syscall_nr;
1100
1101         WARN_ON_ONCE(!chan->sc_table);
1102
1103         syscall_name = get_syscall_name(event);
1104
1105         switch (event->u.syscall.abi) {
1106         case LTTNG_SYSCALL_ABI_NATIVE:
1107                 syscall_nr = get_syscall_nr(syscall_name);
1108                 break;
1109         case LTTNG_SYSCALL_ABI_COMPAT:
1110                 syscall_nr = get_compat_syscall_nr(syscall_name);
1111                 break;
1112         default:
1113                 return -EINVAL;
1114         }
1115         if (syscall_nr < 0)
1116                 return -ENOENT;
1117
1118
1119         switch (event->u.syscall.entryexit) {
1120         case LTTNG_SYSCALL_ENTRY:
1121                 switch (event->u.syscall.abi) {
1122                 case LTTNG_SYSCALL_ABI_NATIVE:
1123                         bitmap = filter->sc_entry;
1124                         break;
1125                 case LTTNG_SYSCALL_ABI_COMPAT:
1126                         bitmap = filter->sc_compat_entry;
1127                         break;
1128                 }
1129                 break;
1130         case LTTNG_SYSCALL_EXIT:
1131                 switch (event->u.syscall.abi) {
1132                 case LTTNG_SYSCALL_ABI_NATIVE:
1133                         bitmap = filter->sc_exit;
1134                         break;
1135                 case LTTNG_SYSCALL_ABI_COMPAT:
1136                         bitmap = filter->sc_compat_exit;
1137                         break;
1138                 }
1139                 break;
1140         default:
1141                 return -EINVAL;
1142         }
1143         if (!test_bit(syscall_nr, bitmap))
1144                 return -EEXIST;
1145         bitmap_clear(bitmap, syscall_nr, 1);
1146
1147         return 0;
1148 }
1149
1150 static
1151 const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
1152 {
1153         const struct trace_syscall_entry *entry;
1154         int iter = 0;
1155
1156         for (entry = sc_table;
1157                         entry < sc_table + ARRAY_SIZE(sc_table);
1158                          entry++) {
1159                 if (iter++ >= *pos)
1160                         return entry;
1161         }
1162         for (entry = compat_sc_table;
1163                         entry < compat_sc_table + ARRAY_SIZE(compat_sc_table);
1164                          entry++) {
1165                 if (iter++ >= *pos)
1166                         return entry;
1167         }
1168         /* End of list */
1169         return NULL;
1170 }
1171
1172 static
1173 void *syscall_list_start(struct seq_file *m, loff_t *pos)
1174 {
1175         return (void *) syscall_list_get_entry(pos);
1176 }
1177
1178 static
1179 void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
1180 {
1181         (*ppos)++;
1182         return (void *) syscall_list_get_entry(ppos);
1183 }
1184
1185 static
1186 void syscall_list_stop(struct seq_file *m, void *p)
1187 {
1188 }
1189
1190 static
1191 int get_sc_table(const struct trace_syscall_entry *entry,
1192                 const struct trace_syscall_entry **table,
1193                 unsigned int *bitness)
1194 {
1195         if (entry >= sc_table && entry < sc_table + ARRAY_SIZE(sc_table)) {
1196                 if (bitness)
1197                         *bitness = BITS_PER_LONG;
1198                 if (table)
1199                         *table = sc_table;
1200                 return 0;
1201         }
1202         if (!(entry >= compat_sc_table
1203                         && entry < compat_sc_table + ARRAY_SIZE(compat_sc_table))) {
1204                 return -EINVAL;
1205         }
1206         if (bitness)
1207                 *bitness = 32;
1208         if (table)
1209                 *table = compat_sc_table;
1210         return 0;
1211 }
1212
1213 static
1214 int syscall_list_show(struct seq_file *m, void *p)
1215 {
1216         const struct trace_syscall_entry *table, *entry = p;
1217         unsigned int bitness;
1218         unsigned long index;
1219         int ret;
1220         const char *name;
1221
1222         ret = get_sc_table(entry, &table, &bitness);
1223         if (ret)
1224                 return ret;
1225         if (!entry->desc)
1226                 return 0;
1227         if (table == sc_table) {
1228                 index = entry - table;
1229                 name = &entry->desc->name[strlen(SYSCALL_ENTRY_STR)];
1230         } else {
1231                 index = (entry - table) + ARRAY_SIZE(sc_table);
1232                 name = &entry->desc->name[strlen(COMPAT_SYSCALL_ENTRY_STR)];
1233         }
1234         seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
1235                 index, name, bitness);
1236         return 0;
1237 }
1238
1239 static
1240 const struct seq_operations lttng_syscall_list_seq_ops = {
1241         .start = syscall_list_start,
1242         .next = syscall_list_next,
1243         .stop = syscall_list_stop,
1244         .show = syscall_list_show,
1245 };
1246
1247 static
1248 int lttng_syscall_list_open(struct inode *inode, struct file *file)
1249 {
1250         return seq_open(file, &lttng_syscall_list_seq_ops);
1251 }
1252
1253 const struct file_operations lttng_syscall_list_fops = {
1254         .owner = THIS_MODULE,
1255         .open = lttng_syscall_list_open,
1256         .read = seq_read,
1257         .llseek = seq_lseek,
1258         .release = seq_release,
1259 };
1260
1261 /*
1262  * A syscall is enabled if it is traced for either entry or exit.
1263  */
1264 long lttng_channel_syscall_mask(struct lttng_channel *channel,
1265                 struct lttng_kernel_syscall_mask __user *usyscall_mask)
1266 {
1267         uint32_t len, sc_tables_len, bitmask_len;
1268         int ret = 0, bit;
1269         char *tmp_mask;
1270         struct lttng_syscall_filter *filter;
1271
1272         ret = get_user(len, &usyscall_mask->len);
1273         if (ret)
1274                 return ret;
1275         sc_tables_len = get_sc_tables_len();
1276         bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
1277         if (len < sc_tables_len) {
1278                 return put_user(sc_tables_len, &usyscall_mask->len);
1279         }
1280         /* Array is large enough, we can copy array to user-space. */
1281         tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
1282         if (!tmp_mask)
1283                 return -ENOMEM;
1284         filter = channel->sc_filter;
1285
1286         for (bit = 0; bit < ARRAY_SIZE(sc_table); bit++) {
1287                 char state;
1288
1289                 if (channel->sc_table) {
1290                         if (!READ_ONCE(channel->syscall_all) && filter)
1291                                 state = test_bit(bit, filter->sc_entry)
1292                                         || test_bit(bit, filter->sc_exit);
1293                         else
1294                                 state = 1;
1295                 } else {
1296                         state = 0;
1297                 }
1298                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1299         }
1300         for (; bit < sc_tables_len; bit++) {
1301                 char state;
1302
1303                 if (channel->compat_sc_table) {
1304                         if (!READ_ONCE(channel->syscall_all) && filter)
1305                                 state = test_bit(bit - ARRAY_SIZE(sc_table),
1306                                                 filter->sc_compat_entry)
1307                                         || test_bit(bit - ARRAY_SIZE(sc_table),
1308                                                 filter->sc_compat_exit);
1309                         else
1310                                 state = 1;
1311                 } else {
1312                         state = 0;
1313                 }
1314                 bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
1315         }
1316         if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
1317                 ret = -EFAULT;
1318         kfree(tmp_mask);
1319         return ret;
1320 }
1321
1322 int lttng_abi_syscall_list(void)
1323 {
1324         struct file *syscall_list_file;
1325         int file_fd, ret;
1326
1327         file_fd = lttng_get_unused_fd();
1328         if (file_fd < 0) {
1329                 ret = file_fd;
1330                 goto fd_error;
1331         }
1332
1333         syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
1334                                           &lttng_syscall_list_fops,
1335                                           NULL, O_RDWR);
1336         if (IS_ERR(syscall_list_file)) {
1337                 ret = PTR_ERR(syscall_list_file);
1338                 goto file_error;
1339         }
1340         ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
1341         if (ret < 0)
1342                 goto open_error;
1343         fd_install(file_fd, syscall_list_file);
1344         return file_fd;
1345
1346 open_error:
1347         fput(syscall_list_file);
1348 file_error:
1349         put_unused_fd(file_fd);
1350 fd_error:
1351         return ret;
1352 }