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
  13 #ifndef ASAN_THREAD_H
  14 #define ASAN_THREAD_H
  15
  16 #include "asan_allocator.h"
  17 #include "asan_internal.h"
  18 #include "asan_fake_stack.h"
  19 #include "asan_stats.h"
  20 #include "sanitizer_common/sanitizer_common.h"
  21 #include "sanitizer_common/sanitizer_libc.h"
  22 #include "sanitizer_common/sanitizer_thread_registry.h"
  23
  24 namespace __asan {
  25
  26 const u32 kInvalidTid = 0xffffff;  // Must fit into 24 bits.
  27 const u32 kMaxNumberOfThreads = (1 << 22);  // 4M
  28
  29 class AsanThread;
  30
  31 // These objects are created for every thread and are never deleted,
  32 // so we can find them by tid even if the thread is long dead.
  33 class AsanThreadContext : public ThreadContextBase {
  34  public:
  35   explicit AsanThreadContext(int tid)
  36       : ThreadContextBase(tid), announced(false),
  37         destructor_iterations(GetPthreadDestructorIterations()), stack_id(0),
  38         thread(nullptr) {}
  39   bool announced;
  40   u8 destructor_iterations;
  41   u32 stack_id;
  42   AsanThread *thread;
  43
  44   void OnCreated(void *arg) override;
  45   void OnFinished() override;
  46 };
  47
  48 // AsanThreadContext objects are never freed, so we need many of them.
  49 COMPILER_CHECK(sizeof(AsanThreadContext) <= 256);
  50
  51 // AsanThread are stored in TSD and destroyed when the thread dies.
  52 class AsanThread {
  53  public:
  54   static AsanThread *Create(thread_callback_t start_routine, void *arg,
  55                             u32 parent_tid, StackTrace *stack, bool detached);
  56   static void TSDDtor(void *tsd);
  57   void Destroy();
  58
  59   void Init();  // Should be called from the thread itself.
  60   thread_return_t ThreadStart(uptr os_id,
  61                               atomic_uintptr_t *signal_thread_is_registered);
  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   struct StackFrameAccess {
  73     uptr offset;
  74     uptr frame_pc;
  75     const char *frame_descr;
  76   };
  77   bool GetStackFrameAccessByAddr(uptr addr, StackFrameAccess *access);
  78
  79   bool AddrIsInStack(uptr addr) {
  80     return addr >= stack_bottom_ && addr < stack_top_;
  81   }
  82
  83   void DeleteFakeStack(int tid) {
  84     if (!fake_stack_) return;
  85     FakeStack *t = fake_stack_;
  86     fake_stack_ = nullptr;
  87     SetTLSFakeStack(nullptr);
  88     t->Destroy(tid);
  89   }
  90
  91   bool has_fake_stack() {
  92     return (reinterpret_cast<uptr>(fake_stack_) > 1);
  93   }
  94
  95   FakeStack *fake_stack() {
  96     if (!__asan_option_detect_stack_use_after_return)
  97       return nullptr;
  98     if (!has_fake_stack())
  99       return AsyncSignalSafeLazyInitFakeStack();
 100     return fake_stack_;
 101   }
 102
 103   // True is this thread is currently unwinding stack (i.e. collecting a stack
 104   // trace). Used to prevent deadlocks on platforms where libc unwinder calls
 105   // malloc internally. See PR17116 for more details.
 106   bool isUnwinding() const { return unwinding_; }
 107   void setUnwinding(bool b) { unwinding_ = b; }
 108
 109   // True if we are in a deadly signal handler.
 110   bool isInDeadlySignal() const { return in_deadly_signal_; }
 111   void setInDeadlySignal(bool b) { in_deadly_signal_ = b; }
 112
 113   AsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; }
 114   AsanStats &stats() { return stats_; }
 115
 116  private:
 117   // NOTE: There is no AsanThread constructor. It is allocated
 118   // via mmap() and *must* be valid in zero-initialized state.
 119   void SetThreadStackAndTls();
 120   void ClearShadowForThreadStackAndTLS();
 121   FakeStack *AsyncSignalSafeLazyInitFakeStack();
 122
 123   AsanThreadContext *context_;
 124   thread_callback_t start_routine_;
 125   void *arg_;
 126   uptr stack_top_;
 127   uptr stack_bottom_;
 128   // stack_size_ == stack_top_ - stack_bottom_;
 129   // It needs to be set in a async-signal-safe manner.
 130   uptr stack_size_;
 131   uptr tls_begin_;
 132   uptr tls_end_;
 133
 134   FakeStack *fake_stack_;
 135   AsanThreadLocalMallocStorage malloc_storage_;
 136   AsanStats stats_;
 137   bool unwinding_;
 138   bool in_deadly_signal_;
 139 };
 140
 141 // ScopedUnwinding is a scope for stacktracing member of a context
 142 class ScopedUnwinding {
 143  public:
 144   explicit ScopedUnwinding(AsanThread *t) : thread(t) {
 145     t->setUnwinding(true);
 146   }
 147   ~ScopedUnwinding() { thread->setUnwinding(false); }
 148
 149  private:
 150   AsanThread *thread;
 151 };
 152
 153 // ScopedDeadlySignal is a scope for handling deadly signals.
 154 class ScopedDeadlySignal {
 155  public:
 156   explicit ScopedDeadlySignal(AsanThread *t) : thread(t) {
 157     if (thread) thread->setInDeadlySignal(true);
 158   }
 159   ~ScopedDeadlySignal() {
 160     if (thread) thread->setInDeadlySignal(false);
 161   }
 162
 163  private:
 164   AsanThread *thread;
 165 };
 166
 167 // Returns a single instance of registry.
 168 ThreadRegistry &asanThreadRegistry();
 169
 170 // Must be called under ThreadRegistryLock.
 171 AsanThreadContext *GetThreadContextByTidLocked(u32 tid);
 172
 173 // Get the current thread. May return 0.
 174 AsanThread *GetCurrentThread();
 175 void SetCurrentThread(AsanThread *t);
 176 u32 GetCurrentTidOrInvalid();
 177 AsanThread *FindThreadByStackAddress(uptr addr);
 178
 179 // Used to handle fork().
 180 void EnsureMainThreadIDIsCorrect();
 181 } // namespace __asan
 182
 183 #endif // ASAN_THREAD_H