lib/asan/asan_rtl.cc

   1 //===-- asan_rtl.cc -------------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is a part of AddressSanitizer, an address sanity checker.
  11 //
  12 // Main file of the ASan run-time library.
  13 //===----------------------------------------------------------------------===//
  14 #include "asan_allocator.h"
  15 #include "asan_interceptors.h"
  16 #include "asan_interface_internal.h"
  17 #include "asan_internal.h"
  18 #include "asan_mapping.h"
  19 #include "asan_poisoning.h"
  20 #include "asan_report.h"
  21 #include "asan_stack.h"
  22 #include "asan_stats.h"
  23 #include "asan_thread.h"
  24 #include "sanitizer_common/sanitizer_atomic.h"
  25 #include "sanitizer_common/sanitizer_flags.h"
  26 #include "sanitizer_common/sanitizer_libc.h"
  27 #include "sanitizer_common/sanitizer_symbolizer.h"
  28 #include "lsan/lsan_common.h"
  29
  30 int __asan_option_detect_stack_use_after_return;  // Global interface symbol.
  31
  32 namespace __asan {
  33
  34 uptr AsanMappingProfile[kAsanMappingProfileSize];
  35
  36 static void AsanDie() {
  37   static atomic_uint32_t num_calls;
  38   if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
  39     // Don't die twice - run a busy loop.
  40     while (1) { }
  41   }
  42   if (flags()->sleep_before_dying) {
  43     Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
  44     SleepForSeconds(flags()->sleep_before_dying);
  45   }
  46   if (flags()->unmap_shadow_on_exit) {
  47     if (kMidMemBeg) {
  48       UnmapOrDie((void*)kLowShadowBeg, kMidMemBeg - kLowShadowBeg);
  49       UnmapOrDie((void*)kMidMemEnd, kHighShadowEnd - kMidMemEnd);
  50     } else {
  51       UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
  52     }
  53   }
  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   ParseCommonFlagsFromString(str);
  92   CHECK((uptr)common_flags()->malloc_context_size <= kStackTraceMax);
  93
  94   ParseFlag(str, &f->quarantine_size, "quarantine_size");
  95   ParseFlag(str, &f->redzone, "redzone");
  96   CHECK_GE(f->redzone, 16);
  97   CHECK(IsPowerOfTwo(f->redzone));
  98
  99   ParseFlag(str, &f->debug, "debug");
 100   ParseFlag(str, &f->report_globals, "report_globals");
 101   ParseFlag(str, &f->check_initialization_order, "check_initialization_order");
 102
 103   ParseFlag(str, &f->replace_str, "replace_str");
 104   ParseFlag(str, &f->replace_intrin, "replace_intrin");
 105   ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
 106   ParseFlag(str, &f->detect_stack_use_after_return,
 107             "detect_stack_use_after_return");
 108   ParseFlag(str, &f->uar_stack_size_log, "uar_stack_size_log");
 109   ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
 110   ParseFlag(str, &f->malloc_fill_byte, "malloc_fill_byte");
 111   ParseFlag(str, &f->exitcode, "exitcode");
 112   ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
 113   ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
 114   ParseFlag(str, &f->handle_segv, "handle_segv");
 115   ParseFlag(str, &f->allow_user_segv_handler, "allow_user_segv_handler");
 116   ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
 117   ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
 118   ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
 119   ParseFlag(str, &f->abort_on_error, "abort_on_error");
 120   ParseFlag(str, &f->print_stats, "print_stats");
 121   ParseFlag(str, &f->print_legend, "print_legend");
 122   ParseFlag(str, &f->atexit, "atexit");
 123   ParseFlag(str, &f->disable_core, "disable_core");
 124   ParseFlag(str, &f->allow_reexec, "allow_reexec");
 125   ParseFlag(str, &f->print_full_thread_history, "print_full_thread_history");
 126   ParseFlag(str, &f->poison_heap, "poison_heap");
 127   ParseFlag(str, &f->alloc_dealloc_mismatch, "alloc_dealloc_mismatch");
 128   ParseFlag(str, &f->use_stack_depot, "use_stack_depot");
 129   ParseFlag(str, &f->strict_memcmp, "strict_memcmp");
 130   ParseFlag(str, &f->strict_init_order, "strict_init_order");
 131 }
 132
 133 void InitializeFlags(Flags *f, const char *env) {
 134   CommonFlags *cf = common_flags();
 135   cf->external_symbolizer_path = GetEnv("ASAN_SYMBOLIZER_PATH");
 136   cf->symbolize = true;
 137   cf->malloc_context_size = kDefaultMallocContextSize;
 138   cf->fast_unwind_on_fatal = false;
 139   cf->fast_unwind_on_malloc = true;
 140   cf->strip_path_prefix = "";
 141   cf->handle_ioctl = false;
 142   cf->log_path = 0;
 143   cf->detect_leaks = false;
 144   cf->leak_check_at_exit = true;
 145
 146   internal_memset(f, 0, sizeof(*f));
 147   f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 26 : 1UL << 28;
 148   f->redzone = 16;
 149   f->debug = false;
 150   f->report_globals = 1;
 151   f->check_initialization_order = false;
 152   f->replace_str = true;
 153   f->replace_intrin = true;
 154   f->mac_ignore_invalid_free = false;
 155   f->detect_stack_use_after_return = false;  // Also needs the compiler flag.
 156   f->uar_stack_size_log = 0;
 157   f->max_malloc_fill_size = 0x1000;  // By default, fill only the first 4K.
 158   f->malloc_fill_byte = 0xbe;
 159   f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
 160   f->allow_user_poisoning = true;
 161   f->sleep_before_dying = 0;
 162   f->handle_segv = ASAN_NEEDS_SEGV;
 163   f->allow_user_segv_handler = false;
 164   f->use_sigaltstack = false;
 165   f->check_malloc_usable_size = true;
 166   f->unmap_shadow_on_exit = false;
 167   f->abort_on_error = false;
 168   f->print_stats = false;
 169   f->print_legend = true;
 170   f->atexit = false;
 171   f->disable_core = (SANITIZER_WORDSIZE == 64);
 172   f->allow_reexec = true;
 173   f->print_full_thread_history = true;
 174   f->poison_heap = true;
 175   // Turn off alloc/dealloc mismatch checker on Mac and Windows for now.
 176   // TODO(glider,timurrrr): Fix known issues and enable this back.
 177   f->alloc_dealloc_mismatch = (SANITIZER_MAC == 0) && (SANITIZER_WINDOWS == 0);
 178   f->use_stack_depot = true;
 179   f->strict_memcmp = true;
 180   f->strict_init_order = false;
 181
 182   // Override from compile definition.
 183   ParseFlagsFromString(f, MaybeUseAsanDefaultOptionsCompileDefiniton());
 184
 185   // Override from user-specified string.
 186   ParseFlagsFromString(f, MaybeCallAsanDefaultOptions());
 187   if (common_flags()->verbosity) {
 188     Report("Using the defaults from __asan_default_options: %s\n",
 189            MaybeCallAsanDefaultOptions());
 190   }
 191
 192   // Override from command line.
 193   ParseFlagsFromString(f, env);
 194
 195 #if !CAN_SANITIZE_LEAKS
 196   if (cf->detect_leaks) {
 197     Report("%s: detect_leaks is not supported on this platform.\n",
 198            SanitizerToolName);
 199     cf->detect_leaks = false;
 200   }
 201 #endif
 202
 203   if (cf->detect_leaks && !f->use_stack_depot) {
 204     Report("%s: detect_leaks is ignored (requires use_stack_depot).\n",
 205            SanitizerToolName);
 206     cf->detect_leaks = false;
 207   }
 208 }
 209
 210 // -------------------------- Globals --------------------- {{{1
 211 int asan_inited;
 212 bool asan_init_is_running;
 213 void (*death_callback)(void);
 214
 215 #if !ASAN_FIXED_MAPPING
 216 uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;
 217 #endif
 218
 219 // -------------------------- Misc ---------------- {{{1
 220 void ShowStatsAndAbort() {
 221   __asan_print_accumulated_stats();
 222   Die();
 223 }
 224
 225 // ---------------------- mmap -------------------- {{{1
 226 // Reserve memory range [beg, end].
 227 static void ReserveShadowMemoryRange(uptr beg, uptr end) {
 228   CHECK_EQ((beg % GetPageSizeCached()), 0);
 229   CHECK_EQ(((end + 1) % GetPageSizeCached()), 0);
 230   uptr size = end - beg + 1;
 231   void *res = MmapFixedNoReserve(beg, size);
 232   if (res != (void*)beg) {
 233     Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
 234            "Perhaps you're using ulimit -v\n", size);
 235     Abort();
 236   }
 237 }
 238
 239 // --------------- LowLevelAllocateCallbac ---------- {{{1
 240 static void OnLowLevelAllocate(uptr ptr, uptr size) {
 241   PoisonShadow(ptr, size, kAsanInternalHeapMagic);
 242 }
 243
 244 // -------------------------- Run-time entry ------------------- {{{1
 245 // exported functions
 246 #define ASAN_REPORT_ERROR(type, is_write, size)                     \
 247 extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
 248 void __asan_report_ ## type ## size(uptr addr);                \
 249 void __asan_report_ ## type ## size(uptr addr) {               \
 250   GET_CALLER_PC_BP_SP;                                              \
 251   __asan_report_error(pc, bp, sp, addr, is_write, size);            \
 252 }
 253
 254 ASAN_REPORT_ERROR(load, false, 1)
 255 ASAN_REPORT_ERROR(load, false, 2)
 256 ASAN_REPORT_ERROR(load, false, 4)
 257 ASAN_REPORT_ERROR(load, false, 8)
 258 ASAN_REPORT_ERROR(load, false, 16)
 259 ASAN_REPORT_ERROR(store, true, 1)
 260 ASAN_REPORT_ERROR(store, true, 2)
 261 ASAN_REPORT_ERROR(store, true, 4)
 262 ASAN_REPORT_ERROR(store, true, 8)
 263 ASAN_REPORT_ERROR(store, true, 16)
 264
 265 #define ASAN_REPORT_ERROR_N(type, is_write)                    \
 266 extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
 267 void __asan_report_ ## type ## _n(uptr addr, uptr size);       \
 268 void __asan_report_ ## type ## _n(uptr addr, uptr size) {      \
 269   GET_CALLER_PC_BP_SP;                                         \
 270   __asan_report_error(pc, bp, sp, addr, is_write, size);       \
 271 }
 272
 273 ASAN_REPORT_ERROR_N(load, false)
 274 ASAN_REPORT_ERROR_N(store, true)
 275
 276 // Force the linker to keep the symbols for various ASan interface functions.
 277 // We want to keep those in the executable in order to let the instrumented
 278 // dynamic libraries access the symbol even if it is not used by the executable
 279 // itself. This should help if the build system is removing dead code at link
 280 // time.
 281 static NOINLINE void force_interface_symbols() {
 282   volatile int fake_condition = 0;  // prevent dead condition elimination.
 283   // __asan_report_* functions are noreturn, so we need a switch to prevent
 284   // the compiler from removing any of them.
 285   switch (fake_condition) {
 286     case 1: __asan_report_load1(0); break;
 287     case 2: __asan_report_load2(0); break;
 288     case 3: __asan_report_load4(0); break;
 289     case 4: __asan_report_load8(0); break;
 290     case 5: __asan_report_load16(0); break;
 291     case 6: __asan_report_store1(0); break;
 292     case 7: __asan_report_store2(0); break;
 293     case 8: __asan_report_store4(0); break;
 294     case 9: __asan_report_store8(0); break;
 295     case 10: __asan_report_store16(0); break;
 296     case 12: __asan_register_globals(0, 0); break;
 297     case 13: __asan_unregister_globals(0, 0); break;
 298     case 14: __asan_set_death_callback(0); break;
 299     case 15: __asan_set_error_report_callback(0); break;
 300     case 16: __asan_handle_no_return(); break;
 301     case 17: __asan_address_is_poisoned(0); break;
 302     case 18: __asan_get_allocated_size(0); break;
 303     case 19: __asan_get_current_allocated_bytes(); break;
 304     case 20: __asan_get_estimated_allocated_size(0); break;
 305     case 21: __asan_get_free_bytes(); break;
 306     case 22: __asan_get_heap_size(); break;
 307     case 23: __asan_get_ownership(0); break;
 308     case 24: __asan_get_unmapped_bytes(); break;
 309     case 25: __asan_poison_memory_region(0, 0); break;
 310     case 26: __asan_unpoison_memory_region(0, 0); break;
 311     case 27: __asan_set_error_exit_code(0); break;
 312     case 30: __asan_before_dynamic_init(0); break;
 313     case 31: __asan_after_dynamic_init(); break;
 314     case 32: __asan_poison_stack_memory(0, 0); break;
 315     case 33: __asan_unpoison_stack_memory(0, 0); break;
 316     case 34: __asan_region_is_poisoned(0, 0); break;
 317     case 35: __asan_describe_address(0); break;
 318   }
 319 }
 320
 321 static void asan_atexit() {
 322   Printf("AddressSanitizer exit stats:\n");
 323   __asan_print_accumulated_stats();
 324   // Print AsanMappingProfile.
 325   for (uptr i = 0; i < kAsanMappingProfileSize; i++) {
 326     if (AsanMappingProfile[i] == 0) continue;
 327     Printf("asan_mapping.h:%zd -- %zd\n", i, AsanMappingProfile[i]);
 328   }
 329 }
 330
 331 static void InitializeHighMemEnd() {
 332 #if !ASAN_FIXED_MAPPING
 333   kHighMemEnd = GetMaxVirtualAddress();
 334   // Increase kHighMemEnd to make sure it's properly
 335   // aligned together with kHighMemBeg:
 336   kHighMemEnd |= SHADOW_GRANULARITY * GetPageSizeCached() - 1;
 337 #endif  // !ASAN_FIXED_MAPPING
 338   CHECK_EQ((kHighMemBeg % GetPageSizeCached()), 0);
 339 }
 340
 341 static void ProtectGap(uptr a, uptr size) {
 342   CHECK_EQ(a, (uptr)Mprotect(a, size));
 343 }
 344
 345 static void PrintAddressSpaceLayout() {
 346   Printf("|| `[%p, %p]` || HighMem    ||\n",
 347          (void*)kHighMemBeg, (void*)kHighMemEnd);
 348   Printf("|| `[%p, %p]` || HighShadow ||\n",
 349          (void*)kHighShadowBeg, (void*)kHighShadowEnd);
 350   if (kMidMemBeg) {
 351     Printf("|| `[%p, %p]` || ShadowGap3 ||\n",
 352            (void*)kShadowGap3Beg, (void*)kShadowGap3End);
 353     Printf("|| `[%p, %p]` || MidMem     ||\n",
 354            (void*)kMidMemBeg, (void*)kMidMemEnd);
 355     Printf("|| `[%p, %p]` || ShadowGap2 ||\n",
 356            (void*)kShadowGap2Beg, (void*)kShadowGap2End);
 357     Printf("|| `[%p, %p]` || MidShadow  ||\n",
 358            (void*)kMidShadowBeg, (void*)kMidShadowEnd);
 359   }
 360   Printf("|| `[%p, %p]` || ShadowGap  ||\n",
 361          (void*)kShadowGapBeg, (void*)kShadowGapEnd);
 362   if (kLowShadowBeg) {
 363     Printf("|| `[%p, %p]` || LowShadow  ||\n",
 364            (void*)kLowShadowBeg, (void*)kLowShadowEnd);
 365     Printf("|| `[%p, %p]` || LowMem     ||\n",
 366            (void*)kLowMemBeg, (void*)kLowMemEnd);
 367   }
 368   Printf("MemToShadow(shadow): %p %p %p %p",
 369          (void*)MEM_TO_SHADOW(kLowShadowBeg),
 370          (void*)MEM_TO_SHADOW(kLowShadowEnd),
 371          (void*)MEM_TO_SHADOW(kHighShadowBeg),
 372          (void*)MEM_TO_SHADOW(kHighShadowEnd));
 373   if (kMidMemBeg) {
 374     Printf(" %p %p",
 375            (void*)MEM_TO_SHADOW(kMidShadowBeg),
 376            (void*)MEM_TO_SHADOW(kMidShadowEnd));
 377   }
 378   Printf("\n");
 379   Printf("red_zone=%zu\n", (uptr)flags()->redzone);
 380   Printf("quarantine_size=%zuM\n", (uptr)flags()->quarantine_size >> 20);
 381   Printf("malloc_context_size=%zu\n",
 382          (uptr)common_flags()->malloc_context_size);
 383
 384   Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
 385   Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
 386   Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
 387   CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
 388   if (kMidMemBeg)
 389     CHECK(kMidShadowBeg > kLowShadowEnd &&
 390           kMidMemBeg > kMidShadowEnd &&
 391           kHighShadowBeg > kMidMemEnd);
 392 }
 393
 394 }  // namespace __asan
 395
 396 // ---------------------- Interface ---------------- {{{1
 397 using namespace __asan;  // NOLINT
 398
 399 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 400 extern "C" {
 401 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 402 const char* __asan_default_options() { return ""; }
 403 }  // extern "C"
 404 #endif
 405
 406 int NOINLINE __asan_set_error_exit_code(int exit_code) {
 407   int old = flags()->exitcode;
 408   flags()->exitcode = exit_code;
 409   return old;
 410 }
 411
 412 void NOINLINE __asan_handle_no_return() {
 413   int local_stack;
 414   AsanThread *curr_thread = GetCurrentThread();
 415   CHECK(curr_thread);
 416   uptr PageSize = GetPageSizeCached();
 417   uptr top = curr_thread->stack_top();
 418   uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
 419   static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
 420   if (top - bottom > kMaxExpectedCleanupSize) {
 421     static bool reported_warning = false;
 422     if (reported_warning)
 423       return;
 424     reported_warning = true;
 425     Report("WARNING: ASan is ignoring requested __asan_handle_no_return: "
 426            "stack top: %p; bottom %p; size: %p (%zd)\n"
 427            "False positive error reports may follow\n"
 428            "For details see "
 429            "http://code.google.com/p/address-sanitizer/issues/detail?id=189\n",
 430            top, bottom, top - bottom, top - bottom);
 431     return;
 432   }
 433   PoisonShadow(bottom, top - bottom, 0);
 434   if (curr_thread->has_fake_stack())
 435     curr_thread->fake_stack()->HandleNoReturn();
 436 }
 437
 438 void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
 439   death_callback = callback;
 440 }
 441
 442 void __asan_init() {
 443   if (asan_inited) return;
 444   SanitizerToolName = "AddressSanitizer";
 445   CHECK(!asan_init_is_running && "ASan init calls itself!");
 446   asan_init_is_running = true;
 447   InitializeHighMemEnd();
 448
 449   // Make sure we are not statically linked.
 450   AsanDoesNotSupportStaticLinkage();
 451
 452   // Install tool-specific callbacks in sanitizer_common.
 453   SetDieCallback(AsanDie);
 454   SetCheckFailedCallback(AsanCheckFailed);
 455   SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
 456
 457   // Initialize flags. This must be done early, because most of the
 458   // initialization steps look at flags().
 459   const char *options = GetEnv("ASAN_OPTIONS");
 460   InitializeFlags(flags(), options);
 461   __sanitizer_set_report_path(common_flags()->log_path);
 462   __asan_option_detect_stack_use_after_return =
 463       flags()->detect_stack_use_after_return;
 464
 465   if (common_flags()->verbosity && options) {
 466     Report("Parsed ASAN_OPTIONS: %s\n", options);
 467   }
 468
 469   // Re-exec ourselves if we need to set additional env or command line args.
 470   MaybeReexec();
 471
 472   // Setup internal allocator callback.
 473   SetLowLevelAllocateCallback(OnLowLevelAllocate);
 474
 475   if (flags()->atexit) {
 476     Atexit(asan_atexit);
 477   }
 478
 479   // interceptors
 480   InitializeAsanInterceptors();
 481
 482   ReplaceSystemMalloc();
 483   ReplaceOperatorsNewAndDelete();
 484
 485   uptr shadow_start = kLowShadowBeg;
 486   if (kLowShadowBeg)
 487     shadow_start -= GetMmapGranularity();
 488   bool full_shadow_is_available =
 489       MemoryRangeIsAvailable(shadow_start, kHighShadowEnd);
 490
 491 #if SANITIZER_LINUX && defined(__x86_64__) && !ASAN_FIXED_MAPPING
 492   if (!full_shadow_is_available) {
 493     kMidMemBeg = kLowMemEnd < 0x3000000000ULL ? 0x3000000000ULL : 0;
 494     kMidMemEnd = kLowMemEnd < 0x3000000000ULL ? 0x4fffffffffULL : 0;
 495   }
 496 #endif
 497
 498   if (common_flags()->verbosity)
 499     PrintAddressSpaceLayout();
 500
 501   if (flags()->disable_core) {
 502     DisableCoreDumper();
 503   }
 504
 505   if (full_shadow_is_available) {
 506     // mmap the low shadow plus at least one page at the left.
 507     if (kLowShadowBeg)
 508       ReserveShadowMemoryRange(shadow_start, kLowShadowEnd);
 509     // mmap the high shadow.
 510     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
 511     // protect the gap.
 512     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
 513   } else if (kMidMemBeg &&
 514       MemoryRangeIsAvailable(shadow_start, kMidMemBeg - 1) &&
 515       MemoryRangeIsAvailable(kMidMemEnd + 1, kHighShadowEnd)) {
 516     CHECK(kLowShadowBeg != kLowShadowEnd);
 517     // mmap the low shadow plus at least one page at the left.
 518     ReserveShadowMemoryRange(shadow_start, kLowShadowEnd);
 519     // mmap the mid shadow.
 520     ReserveShadowMemoryRange(kMidShadowBeg, kMidShadowEnd);
 521     // mmap the high shadow.
 522     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
 523     // protect the gaps.
 524     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
 525     ProtectGap(kShadowGap2Beg, kShadowGap2End - kShadowGap2Beg + 1);
 526     ProtectGap(kShadowGap3Beg, kShadowGap3End - kShadowGap3Beg + 1);
 527   } else {
 528     Report("Shadow memory range interleaves with an existing memory mapping. "
 529            "ASan cannot proceed correctly. ABORTING.\n");
 530     DumpProcessMap();
 531     Die();
 532   }
 533
 534   InstallSignalHandlers();
 535
 536   AsanTSDInit(PlatformTSDDtor);
 537   // Allocator should be initialized before starting external symbolizer, as
 538   // fork() on Mac locks the allocator.
 539   InitializeAllocator();
 540
 541   // Start symbolizer process if necessary.
 542   if (common_flags()->symbolize && &getSymbolizer) {
 543     getSymbolizer()
 544         ->InitializeExternal(common_flags()->external_symbolizer_path);
 545   }
 546
 547   // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
 548   // should be set to 1 prior to initializing the threads.
 549   asan_inited = 1;
 550   asan_init_is_running = false;
 551
 552   InitTlsSize();
 553
 554   // Create main thread.
 555   AsanThread *main_thread = AsanThread::Create(0, 0);
 556   CreateThreadContextArgs create_main_args = { main_thread, 0 };
 557   u32 main_tid = asanThreadRegistry().CreateThread(
 558       0, true, 0, &create_main_args);
 559   CHECK_EQ(0, main_tid);
 560   SetCurrentThread(main_thread);
 561   main_thread->ThreadStart(internal_getpid());
 562   force_interface_symbols();  // no-op.
 563
 564 #if CAN_SANITIZE_LEAKS
 565   __lsan::InitCommonLsan();
 566   if (common_flags()->detect_leaks && common_flags()->leak_check_at_exit) {
 567     Atexit(__lsan::DoLeakCheck);
 568   }
 569 #endif  // CAN_SANITIZE_LEAKS
 570
 571   if (common_flags()->verbosity) {
 572     Report("AddressSanitizer Init done\n");
 573   }
 574 }