libsanitizer/asan/asan_rtl.cc

   1 //===-- asan_rtl.cc -------------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Main file of the ASan run-time library.
  11 //===----------------------------------------------------------------------===//
  12 #include "asan_allocator.h"
  13 #include "asan_interceptors.h"
  14 #include "asan_interface_internal.h"
  15 #include "asan_internal.h"
  16 #include "asan_mapping.h"
  17 #include "asan_poisoning.h"
  18 #include "asan_report.h"
  19 #include "asan_stack.h"
  20 #include "asan_stats.h"
  21 #include "asan_thread.h"
  22 #include "sanitizer_common/sanitizer_atomic.h"
  23 #include "sanitizer_common/sanitizer_flags.h"
  24 #include "sanitizer_common/sanitizer_libc.h"
  25 #include "sanitizer_common/sanitizer_symbolizer.h"
  26 #include "lsan/lsan_common.h"
  27
  28 int __asan_option_detect_stack_use_after_return;  // Global interface symbol.
  29
  30 namespace __asan {
  31
  32 uptr AsanMappingProfile[kAsanMappingProfileSize];
  33
  34 static void AsanDie() {
  35   static atomic_uint32_t num_calls;
  36   if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
  37     // Don't die twice - run a busy loop.
  38     while (1) { }
  39   }
  40   if (flags()->sleep_before_dying) {
  41     Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
  42     SleepForSeconds(flags()->sleep_before_dying);
  43   }
  44   if (flags()->unmap_shadow_on_exit) {
  45     if (kMidMemBeg) {
  46       UnmapOrDie((void*)kLowShadowBeg, kMidMemBeg - kLowShadowBeg);
  47       UnmapOrDie((void*)kMidMemEnd, kHighShadowEnd - kMidMemEnd);
  48     } else {
  49       UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
  50     }
  51   }
  52   if (flags()->coverage)
  53     __sanitizer_cov_dump();
  54   if (death_callback)
  55     death_callback();
  56   if (flags()->abort_on_error)
  57     Abort();
  58   internal__exit(flags()->exitcode);
  59 }
  60
  61 static void AsanCheckFailed(const char *file, int line, const char *cond,
  62                             u64 v1, u64 v2) {
  63   Report("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
  64              file, line, cond, (uptr)v1, (uptr)v2);
  65   // FIXME: check for infinite recursion without a thread-local counter here.
  66   PRINT_CURRENT_STACK();
  67   Die();
  68 }
  69
  70 // -------------------------- Flags ------------------------- {{{1
  71 static const int kDefaultMallocContextSize = 30;
  72
  73 Flags asan_flags_dont_use_directly;  // use via flags().
  74
  75 static const char *MaybeCallAsanDefaultOptions() {
  76   return (&__asan_default_options) ? __asan_default_options() : "";
  77 }
  78
  79 static const char *MaybeUseAsanDefaultOptionsCompileDefiniton() {
  80 #ifdef ASAN_DEFAULT_OPTIONS
  81 // Stringize the macro value.
  82 # define ASAN_STRINGIZE(x) #x
  83 # define ASAN_STRINGIZE_OPTIONS(options) ASAN_STRINGIZE(options)
  84   return ASAN_STRINGIZE_OPTIONS(ASAN_DEFAULT_OPTIONS);
  85 #else
  86   return "";
  87 #endif
  88 }
  89
  90 static void ParseFlagsFromString(Flags *f, const char *str) {
  91   CommonFlags *cf = common_flags();
  92   ParseCommonFlagsFromString(cf, str);
  93   CHECK((uptr)cf->malloc_context_size <= kStackTraceMax);
  94
  95   ParseFlag(str, &f->quarantine_size, "quarantine_size");
  96   ParseFlag(str, &f->redzone, "redzone");
  97   CHECK_GE(f->redzone, 16);
  98   CHECK(IsPowerOfTwo(f->redzone));
  99
 100   ParseFlag(str, &f->debug, "debug");
 101   ParseFlag(str, &f->report_globals, "report_globals");
 102   ParseFlag(str, &f->check_initialization_order, "check_initialization_order");
 103
 104   ParseFlag(str, &f->replace_str, "replace_str");
 105   ParseFlag(str, &f->replace_intrin, "replace_intrin");
 106   ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
 107   ParseFlag(str, &f->detect_stack_use_after_return,
 108             "detect_stack_use_after_return");
 109   ParseFlag(str, &f->uar_stack_size_log, "uar_stack_size_log");
 110   ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
 111   ParseFlag(str, &f->malloc_fill_byte, "malloc_fill_byte");
 112   ParseFlag(str, &f->exitcode, "exitcode");
 113   ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
 114   ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
 115   ParseFlag(str, &f->handle_segv, "handle_segv");
 116   ParseFlag(str, &f->allow_user_segv_handler, "allow_user_segv_handler");
 117   ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
 118   ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
 119   ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
 120   ParseFlag(str, &f->abort_on_error, "abort_on_error");
 121   ParseFlag(str, &f->print_stats, "print_stats");
 122   ParseFlag(str, &f->print_legend, "print_legend");
 123   ParseFlag(str, &f->atexit, "atexit");
 124   ParseFlag(str, &f->coverage, "coverage");
 125   ParseFlag(str, &f->disable_core, "disable_core");
 126   ParseFlag(str, &f->allow_reexec, "allow_reexec");
 127   ParseFlag(str, &f->print_full_thread_history, "print_full_thread_history");
 128   ParseFlag(str, &f->poison_heap, "poison_heap");
 129   ParseFlag(str, &f->poison_partial, "poison_partial");
 130   ParseFlag(str, &f->alloc_dealloc_mismatch, "alloc_dealloc_mismatch");
 131   ParseFlag(str, &f->strict_memcmp, "strict_memcmp");
 132   ParseFlag(str, &f->strict_init_order, "strict_init_order");
 133 }
 134
 135 void InitializeFlags(Flags *f, const char *env) {
 136   CommonFlags *cf = common_flags();
 137   SetCommonFlagsDefaults(cf);
 138   cf->external_symbolizer_path = GetEnv("ASAN_SYMBOLIZER_PATH");
 139   cf->malloc_context_size = kDefaultMallocContextSize;
 140
 141   internal_memset(f, 0, sizeof(*f));
 142   f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 26 : 1UL << 28;
 143   f->redzone = 16;
 144   f->debug = false;
 145   f->report_globals = 1;
 146   f->check_initialization_order = false;
 147   f->replace_str = true;
 148   f->replace_intrin = true;
 149   f->mac_ignore_invalid_free = false;
 150   f->detect_stack_use_after_return = false;  // Also needs the compiler flag.
 151   f->uar_stack_size_log = 0;
 152   f->max_malloc_fill_size = 0x1000;  // By default, fill only the first 4K.
 153   f->malloc_fill_byte = 0xbe;
 154   f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
 155   f->allow_user_poisoning = true;
 156   f->sleep_before_dying = 0;
 157   f->handle_segv = ASAN_NEEDS_SEGV;
 158   f->allow_user_segv_handler = false;
 159   f->use_sigaltstack = false;
 160   f->check_malloc_usable_size = true;
 161   f->unmap_shadow_on_exit = false;
 162   f->abort_on_error = false;
 163   f->print_stats = false;
 164   f->print_legend = true;
 165   f->atexit = false;
 166   f->coverage = false;
 167   f->disable_core = (SANITIZER_WORDSIZE == 64);
 168   f->allow_reexec = true;
 169   f->print_full_thread_history = true;
 170   f->poison_heap = true;
 171   f->poison_partial = true;
 172   // Turn off alloc/dealloc mismatch checker on Mac and Windows for now.
 173   // TODO(glider,timurrrr): Fix known issues and enable this back.
 174   f->alloc_dealloc_mismatch = (SANITIZER_MAC == 0) && (SANITIZER_WINDOWS == 0);
 175   f->strict_memcmp = true;
 176   f->strict_init_order = false;
 177
 178   // Override from compile definition.
 179   ParseFlagsFromString(f, MaybeUseAsanDefaultOptionsCompileDefiniton());
 180
 181   // Override from user-specified string.
 182   ParseFlagsFromString(f, MaybeCallAsanDefaultOptions());
 183   if (cf->verbosity) {
 184     Report("Using the defaults from __asan_default_options: %s\n",
 185            MaybeCallAsanDefaultOptions());
 186   }
 187
 188   // Override from command line.
 189   ParseFlagsFromString(f, env);
 190
 191 #if !CAN_SANITIZE_LEAKS
 192   if (cf->detect_leaks) {
 193     Report("%s: detect_leaks is not supported on this platform.\n",
 194            SanitizerToolName);
 195     cf->detect_leaks = false;
 196   }
 197 #endif
 198
 199   // Make "strict_init_order" imply "check_initialization_order".
 200   // TODO(samsonov): Use a single runtime flag for an init-order checker.
 201   if (f->strict_init_order) {
 202     f->check_initialization_order = true;
 203   }
 204 }
 205
 206 // -------------------------- Globals --------------------- {{{1
 207 int asan_inited;
 208 bool asan_init_is_running;
 209 void (*death_callback)(void);
 210
 211 #if !ASAN_FIXED_MAPPING
 212 uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;
 213 #endif
 214
 215 // -------------------------- Misc ---------------- {{{1
 216 void ShowStatsAndAbort() {
 217   __asan_print_accumulated_stats();
 218   Die();
 219 }
 220
 221 // ---------------------- mmap -------------------- {{{1
 222 // Reserve memory range [beg, end].
 223 static void ReserveShadowMemoryRange(uptr beg, uptr end) {
 224   CHECK_EQ((beg % GetPageSizeCached()), 0);
 225   CHECK_EQ(((end + 1) % GetPageSizeCached()), 0);
 226   uptr size = end - beg + 1;
 227   void *res = MmapFixedNoReserve(beg, size);
 228   if (res != (void*)beg) {
 229     Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
 230            "Perhaps you're using ulimit -v\n", size);
 231     Abort();
 232   }
 233 }
 234
 235 // --------------- LowLevelAllocateCallbac ---------- {{{1
 236 static void OnLowLevelAllocate(uptr ptr, uptr size) {
 237   PoisonShadow(ptr, size, kAsanInternalHeapMagic);
 238 }
 239
 240 // -------------------------- Run-time entry ------------------- {{{1
 241 // exported functions
 242 #define ASAN_REPORT_ERROR(type, is_write, size)                     \
 243 extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
 244 void __asan_report_ ## type ## size(uptr addr);                \
 245 void __asan_report_ ## type ## size(uptr addr) {               \
 246   GET_CALLER_PC_BP_SP;                                              \
 247   __asan_report_error(pc, bp, sp, addr, is_write, size);            \
 248 }
 249
 250 ASAN_REPORT_ERROR(load, false, 1)
 251 ASAN_REPORT_ERROR(load, false, 2)
 252 ASAN_REPORT_ERROR(load, false, 4)
 253 ASAN_REPORT_ERROR(load, false, 8)
 254 ASAN_REPORT_ERROR(load, false, 16)
 255 ASAN_REPORT_ERROR(store, true, 1)
 256 ASAN_REPORT_ERROR(store, true, 2)
 257 ASAN_REPORT_ERROR(store, true, 4)
 258 ASAN_REPORT_ERROR(store, true, 8)
 259 ASAN_REPORT_ERROR(store, true, 16)
 260
 261 #define ASAN_REPORT_ERROR_N(type, is_write)                    \
 262 extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
 263 void __asan_report_ ## type ## _n(uptr addr, uptr size);       \
 264 void __asan_report_ ## type ## _n(uptr addr, uptr size) {      \
 265   GET_CALLER_PC_BP_SP;                                         \
 266   __asan_report_error(pc, bp, sp, addr, is_write, size);       \
 267 }
 268
 269 ASAN_REPORT_ERROR_N(load, false)
 270 ASAN_REPORT_ERROR_N(store, true)
 271
 272 // Force the linker to keep the symbols for various ASan interface functions.
 273 // We want to keep those in the executable in order to let the instrumented
 274 // dynamic libraries access the symbol even if it is not used by the executable
 275 // itself. This should help if the build system is removing dead code at link
 276 // time.
 277 static NOINLINE void force_interface_symbols() {
 278   volatile int fake_condition = 0;  // prevent dead condition elimination.
 279   // __asan_report_* functions are noreturn, so we need a switch to prevent
 280   // the compiler from removing any of them.
 281   switch (fake_condition) {
 282     case 1: __asan_report_load1(0); break;
 283     case 2: __asan_report_load2(0); break;
 284     case 3: __asan_report_load4(0); break;
 285     case 4: __asan_report_load8(0); break;
 286     case 5: __asan_report_load16(0); break;
 287     case 6: __asan_report_store1(0); break;
 288     case 7: __asan_report_store2(0); break;
 289     case 8: __asan_report_store4(0); break;
 290     case 9: __asan_report_store8(0); break;
 291     case 10: __asan_report_store16(0); break;
 292     case 12: __asan_register_globals(0, 0); break;
 293     case 13: __asan_unregister_globals(0, 0); break;
 294     case 14: __asan_set_death_callback(0); break;
 295     case 15: __asan_set_error_report_callback(0); break;
 296     case 16: __asan_handle_no_return(); break;
 297     case 17: __asan_address_is_poisoned(0); break;
 298     case 18: __asan_get_allocated_size(0); break;
 299     case 19: __asan_get_current_allocated_bytes(); break;
 300     case 20: __asan_get_estimated_allocated_size(0); break;
 301     case 21: __asan_get_free_bytes(); break;
 302     case 22: __asan_get_heap_size(); break;
 303     case 23: __asan_get_ownership(0); break;
 304     case 24: __asan_get_unmapped_bytes(); break;
 305     case 25: __asan_poison_memory_region(0, 0); break;
 306     case 26: __asan_unpoison_memory_region(0, 0); break;
 307     case 27: __asan_set_error_exit_code(0); break;
 308     case 30: __asan_before_dynamic_init(0); break;
 309     case 31: __asan_after_dynamic_init(); break;
 310     case 32: __asan_poison_stack_memory(0, 0); break;
 311     case 33: __asan_unpoison_stack_memory(0, 0); break;
 312     case 34: __asan_region_is_poisoned(0, 0); break;
 313     case 35: __asan_describe_address(0); break;
 314   }
 315 }
 316
 317 static void asan_atexit() {
 318   Printf("AddressSanitizer exit stats:\n");
 319   __asan_print_accumulated_stats();
 320   // Print AsanMappingProfile.
 321   for (uptr i = 0; i < kAsanMappingProfileSize; i++) {
 322     if (AsanMappingProfile[i] == 0) continue;
 323     Printf("asan_mapping.h:%zd -- %zd\n", i, AsanMappingProfile[i]);
 324   }
 325 }
 326
 327 static void InitializeHighMemEnd() {
 328 #if !ASAN_FIXED_MAPPING
 329   kHighMemEnd = GetMaxVirtualAddress();
 330   // Increase kHighMemEnd to make sure it's properly
 331   // aligned together with kHighMemBeg:
 332   kHighMemEnd |= SHADOW_GRANULARITY * GetPageSizeCached() - 1;
 333 #endif  // !ASAN_FIXED_MAPPING
 334   CHECK_EQ((kHighMemBeg % GetPageSizeCached()), 0);
 335 }
 336
 337 static void ProtectGap(uptr a, uptr size) {
 338   CHECK_EQ(a, (uptr)Mprotect(a, size));
 339 }
 340
 341 static void PrintAddressSpaceLayout() {
 342   Printf("|| `[%p, %p]` || HighMem    ||\n",
 343          (void*)kHighMemBeg, (void*)kHighMemEnd);
 344   Printf("|| `[%p, %p]` || HighShadow ||\n",
 345          (void*)kHighShadowBeg, (void*)kHighShadowEnd);
 346   if (kMidMemBeg) {
 347     Printf("|| `[%p, %p]` || ShadowGap3 ||\n",
 348            (void*)kShadowGap3Beg, (void*)kShadowGap3End);
 349     Printf("|| `[%p, %p]` || MidMem     ||\n",
 350            (void*)kMidMemBeg, (void*)kMidMemEnd);
 351     Printf("|| `[%p, %p]` || ShadowGap2 ||\n",
 352            (void*)kShadowGap2Beg, (void*)kShadowGap2End);
 353     Printf("|| `[%p, %p]` || MidShadow  ||\n",
 354            (void*)kMidShadowBeg, (void*)kMidShadowEnd);
 355   }
 356   Printf("|| `[%p, %p]` || ShadowGap  ||\n",
 357          (void*)kShadowGapBeg, (void*)kShadowGapEnd);
 358   if (kLowShadowBeg) {
 359     Printf("|| `[%p, %p]` || LowShadow  ||\n",
 360            (void*)kLowShadowBeg, (void*)kLowShadowEnd);
 361     Printf("|| `[%p, %p]` || LowMem     ||\n",
 362            (void*)kLowMemBeg, (void*)kLowMemEnd);
 363   }
 364   Printf("MemToShadow(shadow): %p %p %p %p",
 365          (void*)MEM_TO_SHADOW(kLowShadowBeg),
 366          (void*)MEM_TO_SHADOW(kLowShadowEnd),
 367          (void*)MEM_TO_SHADOW(kHighShadowBeg),
 368          (void*)MEM_TO_SHADOW(kHighShadowEnd));
 369   if (kMidMemBeg) {
 370     Printf(" %p %p",
 371            (void*)MEM_TO_SHADOW(kMidShadowBeg),
 372            (void*)MEM_TO_SHADOW(kMidShadowEnd));
 373   }
 374   Printf("\n");
 375   Printf("red_zone=%zu\n", (uptr)flags()->redzone);
 376   Printf("quarantine_size=%zuM\n", (uptr)flags()->quarantine_size >> 20);
 377   Printf("malloc_context_size=%zu\n",
 378          (uptr)common_flags()->malloc_context_size);
 379
 380   Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
 381   Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
 382   Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
 383   CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
 384   if (kMidMemBeg)
 385     CHECK(kMidShadowBeg > kLowShadowEnd &&
 386           kMidMemBeg > kMidShadowEnd &&
 387           kHighShadowBeg > kMidMemEnd);
 388 }
 389
 390 }  // namespace __asan
 391
 392 // ---------------------- Interface ---------------- {{{1
 393 using namespace __asan;  // NOLINT
 394
 395 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 396 extern "C" {
 397 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 398 const char* __asan_default_options() { return ""; }
 399 }  // extern "C"
 400 #endif
 401
 402 int NOINLINE __asan_set_error_exit_code(int exit_code) {
 403   int old = flags()->exitcode;
 404   flags()->exitcode = exit_code;
 405   return old;
 406 }
 407
 408 void NOINLINE __asan_handle_no_return() {
 409   int local_stack;
 410   AsanThread *curr_thread = GetCurrentThread();
 411   CHECK(curr_thread);
 412   uptr PageSize = GetPageSizeCached();
 413   uptr top = curr_thread->stack_top();
 414   uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
 415   static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
 416   if (top - bottom > kMaxExpectedCleanupSize) {
 417     static bool reported_warning = false;
 418     if (reported_warning)
 419       return;
 420     reported_warning = true;
 421     Report("WARNING: ASan is ignoring requested __asan_handle_no_return: "
 422            "stack top: %p; bottom %p; size: %p (%zd)\n"
 423            "False positive error reports may follow\n"
 424            "For details see "
 425            "http://code.google.com/p/address-sanitizer/issues/detail?id=189\n",
 426            top, bottom, top - bottom, top - bottom);
 427     return;
 428   }
 429   PoisonShadow(bottom, top - bottom, 0);
 430   if (curr_thread->has_fake_stack())
 431     curr_thread->fake_stack()->HandleNoReturn();
 432 }
 433
 434 void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
 435   death_callback = callback;
 436 }
 437
 438 void __asan_init() {
 439   if (asan_inited) return;
 440   SanitizerToolName = "AddressSanitizer";
 441   CHECK(!asan_init_is_running && "ASan init calls itself!");
 442   asan_init_is_running = true;
 443   InitializeHighMemEnd();
 444
 445   // Make sure we are not statically linked.
 446   AsanDoesNotSupportStaticLinkage();
 447
 448   // Install tool-specific callbacks in sanitizer_common.
 449   SetDieCallback(AsanDie);
 450   SetCheckFailedCallback(AsanCheckFailed);
 451   SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
 452
 453   // Initialize flags. This must be done early, because most of the
 454   // initialization steps look at flags().
 455   const char *options = GetEnv("ASAN_OPTIONS");
 456   InitializeFlags(flags(), options);
 457   __sanitizer_set_report_path(common_flags()->log_path);
 458   __asan_option_detect_stack_use_after_return =
 459       flags()->detect_stack_use_after_return;
 460
 461   if (common_flags()->verbosity && options) {
 462     Report("Parsed ASAN_OPTIONS: %s\n", options);
 463   }
 464
 465   // Re-exec ourselves if we need to set additional env or command line args.
 466   MaybeReexec();
 467
 468   // Setup internal allocator callback.
 469   SetLowLevelAllocateCallback(OnLowLevelAllocate);
 470
 471   InitializeAsanInterceptors();
 472
 473   ReplaceSystemMalloc();
 474   ReplaceOperatorsNewAndDelete();
 475
 476   uptr shadow_start = kLowShadowBeg;
 477   if (kLowShadowBeg)
 478     shadow_start -= GetMmapGranularity();
 479   bool full_shadow_is_available =
 480       MemoryRangeIsAvailable(shadow_start, kHighShadowEnd);
 481
 482 #if SANITIZER_LINUX && defined(__x86_64__) && !ASAN_FIXED_MAPPING
 483   if (!full_shadow_is_available) {
 484     kMidMemBeg = kLowMemEnd < 0x3000000000ULL ? 0x3000000000ULL : 0;
 485     kMidMemEnd = kLowMemEnd < 0x3000000000ULL ? 0x4fffffffffULL : 0;
 486   }
 487 #endif
 488
 489   if (common_flags()->verbosity)
 490     PrintAddressSpaceLayout();
 491
 492   if (flags()->disable_core) {
 493     DisableCoreDumper();
 494   }
 495
 496   if (full_shadow_is_available) {
 497     // mmap the low shadow plus at least one page at the left.
 498     if (kLowShadowBeg)
 499       ReserveShadowMemoryRange(shadow_start, kLowShadowEnd);
 500     // mmap the high shadow.
 501     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
 502     // protect the gap.
 503     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
 504   } else if (kMidMemBeg &&
 505       MemoryRangeIsAvailable(shadow_start, kMidMemBeg - 1) &&
 506       MemoryRangeIsAvailable(kMidMemEnd + 1, kHighShadowEnd)) {
 507     CHECK(kLowShadowBeg != kLowShadowEnd);
 508     // mmap the low shadow plus at least one page at the left.
 509     ReserveShadowMemoryRange(shadow_start, kLowShadowEnd);
 510     // mmap the mid shadow.
 511     ReserveShadowMemoryRange(kMidShadowBeg, kMidShadowEnd);
 512     // mmap the high shadow.
 513     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
 514     // protect the gaps.
 515     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
 516     ProtectGap(kShadowGap2Beg, kShadowGap2End - kShadowGap2Beg + 1);
 517     ProtectGap(kShadowGap3Beg, kShadowGap3End - kShadowGap3Beg + 1);
 518   } else {
 519     Report("Shadow memory range interleaves with an existing memory mapping. "
 520            "ASan cannot proceed correctly. ABORTING.\n");
 521     DumpProcessMap();
 522     Die();
 523   }
 524
 525   AsanTSDInit(PlatformTSDDtor);
 526   InstallSignalHandlers();
 527
 528   // Allocator should be initialized before starting external symbolizer, as
 529   // fork() on Mac locks the allocator.
 530   InitializeAllocator();
 531
 532   // Start symbolizer process if necessary.
 533   if (common_flags()->symbolize) {
 534     Symbolizer::Init(common_flags()->external_symbolizer_path);
 535   } else {
 536     Symbolizer::Disable();
 537   }
 538
 539   // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
 540   // should be set to 1 prior to initializing the threads.
 541   asan_inited = 1;
 542   asan_init_is_running = false;
 543
 544   if (flags()->atexit)
 545     Atexit(asan_atexit);
 546
 547   if (flags()->coverage)
 548     Atexit(__sanitizer_cov_dump);
 549
 550   // interceptors
 551   InitTlsSize();
 552
 553   // Create main thread.
 554   AsanThread *main_thread = AsanThread::Create(0, 0);
 555   CreateThreadContextArgs create_main_args = { main_thread, 0 };
 556   u32 main_tid = asanThreadRegistry().CreateThread(
 557       0, true, 0, &create_main_args);
 558   CHECK_EQ(0, main_tid);
 559   SetCurrentThread(main_thread);
 560   main_thread->ThreadStart(internal_getpid());
 561   force_interface_symbols();  // no-op.
 562
 563 #if CAN_SANITIZE_LEAKS
 564   __lsan::InitCommonLsan();
 565   if (common_flags()->detect_leaks && common_flags()->leak_check_at_exit) {
 566     Atexit(__lsan::DoLeakCheck);
 567   }
 568 #endif  // CAN_SANITIZE_LEAKS
 569
 570   if (common_flags()->verbosity) {
 571     Report("AddressSanitizer Init done\n");
 572   }
 573 }