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      1 //===-- asan_thread.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 // Thread-related code.
     13 //===----------------------------------------------------------------------===//
     14 #include "asan_allocator.h"
     15 #include "asan_interceptors.h"
     16 #include "asan_stack.h"
     17 #include "asan_thread.h"
     18 #include "asan_thread_registry.h"
     19 #include "asan_mapping.h"
     20 #include "sanitizer_common/sanitizer_common.h"
     21 
     22 namespace __asan {
     23 
     24 AsanThread::AsanThread(LinkerInitialized x)
     25     : fake_stack_(x),
     26       malloc_storage_(x),
     27       stats_(x) { }
     28 
     29 AsanThread *AsanThread::Create(u32 parent_tid, thread_callback_t start_routine,
     30                                void *arg, StackTrace *stack) {
     31   uptr PageSize = GetPageSizeCached();
     32   uptr size = RoundUpTo(sizeof(AsanThread), PageSize);
     33   AsanThread *thread = (AsanThread*)MmapOrDie(size, __FUNCTION__);
     34   thread->start_routine_ = start_routine;
     35   thread->arg_ = arg;
     36 
     37   const uptr kSummaryAllocSize = PageSize;
     38   CHECK_LE(sizeof(AsanThreadSummary), kSummaryAllocSize);
     39   AsanThreadSummary *summary =
     40       (AsanThreadSummary*)MmapOrDie(PageSize, "AsanThreadSummary");
     41   summary->Init(parent_tid, stack);
     42   summary->set_thread(thread);
     43   thread->set_summary(summary);
     44 
     45   return thread;
     46 }
     47 
     48 void AsanThreadSummary::TSDDtor(void *tsd) {
     49   AsanThreadSummary *summary = (AsanThreadSummary*)tsd;
     50   if (flags()->verbosity >= 1) {
     51     Report("T%d TSDDtor\n", summary->tid());
     52   }
     53   if (summary->thread()) {
     54     summary->thread()->Destroy();
     55   }
     56 }
     57 
     58 void AsanThread::Destroy() {
     59   if (flags()->verbosity >= 1) {
     60     Report("T%d exited\n", tid());
     61   }
     62 
     63   asanThreadRegistry().UnregisterThread(this);
     64   CHECK(summary()->thread() == 0);
     65   // We also clear the shadow on thread destruction because
     66   // some code may still be executing in later TSD destructors
     67   // and we don't want it to have any poisoned stack.
     68   ClearShadowForThreadStack();
     69   fake_stack().Cleanup();
     70   uptr size = RoundUpTo(sizeof(AsanThread), GetPageSizeCached());
     71   UnmapOrDie(this, size);
     72 }
     73 
     74 void AsanThread::Init() {
     75   SetThreadStackTopAndBottom();
     76   CHECK(AddrIsInMem(stack_bottom_));
     77   CHECK(AddrIsInMem(stack_top_ - 1));
     78   ClearShadowForThreadStack();
     79   if (flags()->verbosity >= 1) {
     80     int local = 0;
     81     Report("T%d: stack [%p,%p) size 0x%zx; local=%p\n",
     82            tid(), (void*)stack_bottom_, (void*)stack_top_,
     83            stack_top_ - stack_bottom_, &local);
     84   }
     85   fake_stack_.Init(stack_size());
     86   AsanPlatformThreadInit();
     87 }
     88 
     89 thread_return_t AsanThread::ThreadStart() {
     90   Init();
     91   if (flags()->use_sigaltstack) SetAlternateSignalStack();
     92 
     93   if (!start_routine_) {
     94     // start_routine_ == 0 if we're on the main thread or on one of the
     95     // OS X libdispatch worker threads. But nobody is supposed to call
     96     // ThreadStart() for the worker threads.
     97     CHECK(tid() == 0);
     98     return 0;
     99   }
    100 
    101   thread_return_t res = start_routine_(arg_);
    102   malloc_storage().CommitBack();
    103   if (flags()->use_sigaltstack) UnsetAlternateSignalStack();
    104 
    105   this->Destroy();
    106 
    107   return res;
    108 }
    109 
    110 void AsanThread::SetThreadStackTopAndBottom() {
    111   GetThreadStackTopAndBottom(tid() == 0, &stack_top_, &stack_bottom_);
    112   int local;
    113   CHECK(AddrIsInStack((uptr)&local));
    114 }
    115 
    116 void AsanThread::ClearShadowForThreadStack() {
    117   PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0);
    118 }
    119 
    120 const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset) {
    121   uptr bottom = 0;
    122   if (AddrIsInStack(addr)) {
    123     bottom = stack_bottom();
    124   } else {
    125     bottom = fake_stack().AddrIsInFakeStack(addr);
    126     CHECK(bottom);
    127     *offset = addr - bottom;
    128     return  (const char *)((uptr*)bottom)[1];
    129   }
    130   uptr aligned_addr = addr & ~(SANITIZER_WORDSIZE/8 - 1);  // align addr.
    131   u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
    132   u8 *shadow_bottom = (u8*)MemToShadow(bottom);
    133 
    134   while (shadow_ptr >= shadow_bottom &&
    135          *shadow_ptr != kAsanStackLeftRedzoneMagic) {
    136     shadow_ptr--;
    137   }
    138 
    139   while (shadow_ptr >= shadow_bottom &&
    140          *shadow_ptr == kAsanStackLeftRedzoneMagic) {
    141     shadow_ptr--;
    142   }
    143 
    144   if (shadow_ptr < shadow_bottom) {
    145     *offset = 0;
    146     return "UNKNOWN";
    147   }
    148 
    149   uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1));
    150   CHECK(ptr[0] == kCurrentStackFrameMagic);
    151   *offset = addr - (uptr)ptr;
    152   return (const char*)ptr[1];
    153 }
    154 
    155 }  // namespace __asan
    156