libsanitizer/asan/asan_thread.h

   1 //===-- asan_thread.h -------------------------------------------*- C++ -*-===//
   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 // ASan-private header for asan_thread.cc.
  11 //===----------------------------------------------------------------------===//
  12 #ifndef ASAN_THREAD_H
  13 #define ASAN_THREAD_H
  14
  15 #include "asan_allocator.h"
  16 #include "asan_internal.h"
  17 #include "asan_fake_stack.h"
  18 #include "asan_stats.h"
  19 #include "sanitizer_common/sanitizer_common.h"
  20 #include "sanitizer_common/sanitizer_libc.h"
  21 #include "sanitizer_common/sanitizer_thread_registry.h"
  22
  23 namespace __asan {
  24
  25 const u32 kInvalidTid = 0xffffff;  // Must fit into 24 bits.
  26 const u32 kMaxNumberOfThreads = (1 << 22);  // 4M
  27
  28 class AsanThread;
  29
  30 // These objects are created for every thread and are never deleted,
  31 // so we can find them by tid even if the thread is long dead.
  32 class AsanThreadContext : public ThreadContextBase {
  33  public:
  34   explicit AsanThreadContext(int tid)
  35       : ThreadContextBase(tid),
  36         announced(false),
  37         destructor_iterations(kPthreadDestructorIterations),
  38         stack_id(0),
  39         thread(0) {
  40   }
  41   bool announced;
  42   u8 destructor_iterations;
  43   u32 stack_id;
  44   AsanThread *thread;
  45
  46   void OnCreated(void *arg);
  47   void OnFinished();
  48 };
  49
  50 // AsanThreadContext objects are never freed, so we need many of them.
  51 COMPILER_CHECK(sizeof(AsanThreadContext) <= 256);
  52
  53 // AsanThread are stored in TSD and destroyed when the thread dies.
  54 class AsanThread {
  55  public:
  56   static AsanThread *Create(thread_callback_t start_routine, void *arg);
  57   static void TSDDtor(void *tsd);
  58   void Destroy();
  59
  60   void Init();  // Should be called from the thread itself.
  61   thread_return_t ThreadStart(uptr os_id);
  62
  63   uptr stack_top() { return stack_top_; }
  64   uptr stack_bottom() { return stack_bottom_; }
  65   uptr stack_size() { return stack_size_; }
  66   uptr tls_begin() { return tls_begin_; }
  67   uptr tls_end() { return tls_end_; }
  68   u32 tid() { return context_->tid; }
  69   AsanThreadContext *context() { return context_; }
  70   void set_context(AsanThreadContext *context) { context_ = context; }
  71
  72   const char *GetFrameNameByAddr(uptr addr, uptr *offset, uptr *frame_pc);
  73
  74   bool AddrIsInStack(uptr addr) {
  75     return addr >= stack_bottom_ && addr < stack_top_;
  76   }
  77
  78   void DeleteFakeStack(int tid) {
  79     if (!fake_stack_) return;
  80     FakeStack *t = fake_stack_;
  81     fake_stack_ = 0;
  82     SetTLSFakeStack(0);
  83     t->Destroy(tid);
  84   }
  85
  86   bool has_fake_stack() {
  87     return (reinterpret_cast<uptr>(fake_stack_) > 1);
  88   }
  89
  90   FakeStack *fake_stack() {
  91     if (!__asan_option_detect_stack_use_after_return)
  92       return 0;
  93     if (!has_fake_stack())
  94       return AsyncSignalSafeLazyInitFakeStack();
  95     return fake_stack_;
  96   }
  97
  98   // True is this thread is currently unwinding stack (i.e. collecting a stack
  99   // trace). Used to prevent deadlocks on platforms where libc unwinder calls
 100   // malloc internally. See PR17116 for more details.
 101   bool isUnwinding() const { return unwinding_; }
 102   void setUnwinding(bool b) { unwinding_ = b; }
 103
 104   AsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; }
 105   AsanStats &stats() { return stats_; }
 106
 107  private:
 108   // NOTE: There is no AsanThread constructor. It is allocated
 109   // via mmap() and *must* be valid in zero-initialized state.
 110   void SetThreadStackAndTls();
 111   void ClearShadowForThreadStackAndTLS();
 112   FakeStack *AsyncSignalSafeLazyInitFakeStack();
 113
 114   AsanThreadContext *context_;
 115   thread_callback_t start_routine_;
 116   void *arg_;
 117   uptr stack_top_;
 118   uptr stack_bottom_;
 119   // stack_size_ == stack_top_ - stack_bottom_;
 120   // It needs to be set in a async-signal-safe manner.
 121   uptr stack_size_;
 122   uptr tls_begin_;
 123   uptr tls_end_;
 124
 125   FakeStack *fake_stack_;
 126   AsanThreadLocalMallocStorage malloc_storage_;
 127   AsanStats stats_;
 128   bool unwinding_;
 129 };
 130
 131 // ScopedUnwinding is a scope for stacktracing member of a context
 132 class ScopedUnwinding {
 133  public:
 134   explicit ScopedUnwinding(AsanThread *t) : thread(t) {
 135     t->setUnwinding(true);
 136   }
 137   ~ScopedUnwinding() { thread->setUnwinding(false); }
 138
 139  private:
 140   AsanThread *thread;
 141 };
 142
 143 struct CreateThreadContextArgs {
 144   AsanThread *thread;
 145   StackTrace *stack;
 146 };
 147
 148 // Returns a single instance of registry.
 149 ThreadRegistry &asanThreadRegistry();
 150
 151 // Must be called under ThreadRegistryLock.
 152 AsanThreadContext *GetThreadContextByTidLocked(u32 tid);
 153
 154 // Get the current thread. May return 0.
 155 AsanThread *GetCurrentThread();
 156 void SetCurrentThread(AsanThread *t);
 157 u32 GetCurrentTidOrInvalid();
 158 AsanThread *FindThreadByStackAddress(uptr addr);
 159
 160 // Used to handle fork().
 161 void EnsureMainThreadIDIsCorrect();
 162 }  // namespace __asan
 163
 164 #endif  // ASAN_THREAD_H