libsanitizer/asan/asan_thread.h

   1 //===-- asan_thread.h -------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of AddressSanitizer, an address sanity checker.
  10 //
  11 // ASan-private header for asan_thread.cpp.
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef ASAN_THREAD_H
  15 #define ASAN_THREAD_H
  16
  17 #include "asan_allocator.h"
  18 #include "asan_internal.h"
  19 #include "asan_fake_stack.h"
  20 #include "asan_stats.h"
  21 #include "sanitizer_common/sanitizer_common.h"
  22 #include "sanitizer_common/sanitizer_libc.h"
  23 #include "sanitizer_common/sanitizer_thread_registry.h"
  24
  25 namespace __sanitizer {
  26 struct DTLS;
  27 }  // namespace __sanitizer
  28
  29 namespace __asan {
  30
  31 class AsanThread;
  32
  33 // These objects are created for every thread and are never deleted,
  34 // so we can find them by tid even if the thread is long dead.
  35 class AsanThreadContext final : public ThreadContextBase {
  36  public:
  37   explicit AsanThreadContext(int tid)
  38       : ThreadContextBase(tid), announced(false),
  39         destructor_iterations(GetPthreadDestructorIterations()), stack_id(0),
  40         thread(nullptr) {}
  41   bool announced;
  42   u8 destructor_iterations;
  43   u32 stack_id;
  44   AsanThread *thread;
  45
  46   void OnCreated(void *arg) override;
  47   void OnFinished() override;
  48
  49   struct CreateThreadContextArgs {
  50     AsanThread *thread;
  51     StackTrace *stack;
  52   };
  53 };
  54
  55 // AsanThreadContext objects are never freed, so we need many of them.
  56 COMPILER_CHECK(sizeof(AsanThreadContext) <= 256);
  57
  58 // AsanThread are stored in TSD and destroyed when the thread dies.
  59 class AsanThread {
  60  public:
  61   static AsanThread *Create(thread_callback_t start_routine, void *arg,
  62                             u32 parent_tid, StackTrace *stack, bool detached);
  63   static void TSDDtor(void *tsd);
  64   void Destroy();
  65
  66   struct InitOptions;
  67   void Init(const InitOptions *options = nullptr);
  68
  69   thread_return_t ThreadStart(tid_t os_id);
  70
  71   uptr stack_top();
  72   uptr stack_bottom();
  73   uptr stack_size();
  74   uptr tls_begin() { return tls_begin_; }
  75   uptr tls_end() { return tls_end_; }
  76   DTLS *dtls() { return dtls_; }
  77   u32 tid() { return context_->tid; }
  78   AsanThreadContext *context() { return context_; }
  79   void set_context(AsanThreadContext *context) { context_ = context; }
  80
  81   struct StackFrameAccess {
  82     uptr offset;
  83     uptr frame_pc;
  84     const char *frame_descr;
  85   };
  86   bool GetStackFrameAccessByAddr(uptr addr, StackFrameAccess *access);
  87
  88   // Returns a pointer to the start of the stack variable's shadow memory.
  89   uptr GetStackVariableShadowStart(uptr addr);
  90
  91   bool AddrIsInStack(uptr addr);
  92
  93   void DeleteFakeStack(int tid) {
  94     if (!fake_stack_) return;
  95     FakeStack *t = fake_stack_;
  96     fake_stack_ = nullptr;
  97     SetTLSFakeStack(nullptr);
  98     t->Destroy(tid);
  99   }
 100
 101   void StartSwitchFiber(FakeStack **fake_stack_save, uptr bottom, uptr size);
 102   void FinishSwitchFiber(FakeStack *fake_stack_save, uptr *bottom_old,
 103                          uptr *size_old);
 104
 105   FakeStack *get_fake_stack() {
 106     if (atomic_load(&stack_switching_, memory_order_relaxed))
 107       return nullptr;
 108     if (reinterpret_cast<uptr>(fake_stack_) <= 1)
 109       return nullptr;
 110     return fake_stack_;
 111   }
 112
 113   FakeStack *get_or_create_fake_stack() {
 114     if (atomic_load(&stack_switching_, memory_order_relaxed))
 115       return nullptr;
 116     if (reinterpret_cast<uptr>(fake_stack_) <= 1)
 117       return AsyncSignalSafeLazyInitFakeStack();
 118     return fake_stack_;
 119   }
 120
 121   // True is this thread is currently unwinding stack (i.e. collecting a stack
 122   // trace). Used to prevent deadlocks on platforms where libc unwinder calls
 123   // malloc internally. See PR17116 for more details.
 124   bool isUnwinding() const { return unwinding_; }
 125   void setUnwinding(bool b) { unwinding_ = b; }
 126
 127   AsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; }
 128   AsanStats &stats() { return stats_; }
 129
 130   void *extra_spill_area() { return &extra_spill_area_; }
 131
 132   void *get_arg() { return arg_; }
 133
 134  private:
 135   // NOTE: There is no AsanThread constructor. It is allocated
 136   // via mmap() and *must* be valid in zero-initialized state.
 137
 138   void SetThreadStackAndTls(const InitOptions *options);
 139
 140   void ClearShadowForThreadStackAndTLS();
 141   FakeStack *AsyncSignalSafeLazyInitFakeStack();
 142
 143   struct StackBounds {
 144     uptr bottom;
 145     uptr top;
 146   };
 147   StackBounds GetStackBounds() const;
 148
 149   AsanThreadContext *context_;
 150   thread_callback_t start_routine_;
 151   void *arg_;
 152
 153   uptr stack_top_;
 154   uptr stack_bottom_;
 155   // these variables are used when the thread is about to switch stack
 156   uptr next_stack_top_;
 157   uptr next_stack_bottom_;
 158   // true if switching is in progress
 159   atomic_uint8_t stack_switching_;
 160
 161   uptr tls_begin_;
 162   uptr tls_end_;
 163   DTLS *dtls_;
 164
 165   FakeStack *fake_stack_;
 166   AsanThreadLocalMallocStorage malloc_storage_;
 167   AsanStats stats_;
 168   bool unwinding_;
 169   uptr extra_spill_area_;
 170 };
 171
 172 // Returns a single instance of registry.
 173 ThreadRegistry &asanThreadRegistry();
 174
 175 // Must be called under ThreadRegistryLock.
 176 AsanThreadContext *GetThreadContextByTidLocked(u32 tid);
 177
 178 // Get the current thread. May return 0.
 179 AsanThread *GetCurrentThread();
 180 void SetCurrentThread(AsanThread *t);
 181 u32 GetCurrentTidOrInvalid();
 182 AsanThread *FindThreadByStackAddress(uptr addr);
 183
 184 // Used to handle fork().
 185 void EnsureMainThreadIDIsCorrect();
 186 } // namespace __asan
 187
 188 #endif // ASAN_THREAD_H