compiler-rt/lib/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_fake_stack.h"
  19 #include "asan_internal.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_arg_retval.h"
  24 #include "sanitizer_common/sanitizer_thread_registry.h"
  25
  26 namespace __sanitizer {
  27 struct DTLS;
  28 }  // namespace __sanitizer
  29
  30 namespace __asan {
  31
  32 class AsanThread;
  33
  34 // These objects are created for every thread and are never deleted,
  35 // so we can find them by tid even if the thread is long dead.
  36 class AsanThreadContext final : public ThreadContextBase {
  37  public:
  38   explicit AsanThreadContext(int tid)
  39       : ThreadContextBase(tid),
  40         announced(false),
  41         destructor_iterations(GetPthreadDestructorIterations()),
  42         thread(nullptr) {}
  43   bool announced;
  44   u8 destructor_iterations;
  45   AsanThread *thread;
  46
  47   void OnCreated(void *arg) override;
  48   void OnFinished() override;
  49 };
  50
  51 // AsanThreadContext objects are never freed, so we need many of them.
  52 COMPILER_CHECK(sizeof(AsanThreadContext) <= 256);
  53
  54 #if defined(_MSC_VER) && !defined(__clang__)
  55 // MSVC raises a warning about a nonstandard extension being used for the 0
  56 // sized element in this array. Disable this for warn-as-error builds.
  57 #  pragma warning(push)
  58 #  pragma warning(disable : 4200)
  59 #endif
  60
  61 // AsanThread are stored in TSD and destroyed when the thread dies.
  62 class AsanThread {
  63  public:
  64   template <typename T>
  65   static AsanThread *Create(const T &data, u32 parent_tid, StackTrace *stack,
  66                             bool detached) {
  67     return Create(&data, sizeof(data), parent_tid, stack, detached);
  68   }
  69   static AsanThread *Create(u32 parent_tid, StackTrace *stack, bool detached) {
  70     return Create(nullptr, 0, parent_tid, stack, detached);
  71   }
  72   static void TSDDtor(void *tsd);
  73   void Destroy();
  74
  75   struct InitOptions;
  76   void Init(const InitOptions *options = nullptr);
  77
  78   void ThreadStart(tid_t os_id);
  79   thread_return_t RunThread();
  80
  81   uptr stack_top();
  82   uptr stack_bottom();
  83   uptr stack_size();
  84   uptr tls_begin() { return tls_begin_; }
  85   uptr tls_end() { return tls_end_; }
  86   DTLS *dtls() { return dtls_; }
  87   u32 tid() { return context_->tid; }
  88   AsanThreadContext *context() { return context_; }
  89   void set_context(AsanThreadContext *context) { context_ = context; }
  90
  91   struct StackFrameAccess {
  92     uptr offset;
  93     uptr frame_pc;
  94     const char *frame_descr;
  95   };
  96   bool GetStackFrameAccessByAddr(uptr addr, StackFrameAccess *access);
  97
  98   // Returns a pointer to the start of the stack variable's shadow memory.
  99   uptr GetStackVariableShadowStart(uptr addr);
 100
 101   bool AddrIsInStack(uptr addr);
 102
 103   void DeleteFakeStack(int tid) {
 104     if (!fake_stack_) return;
 105     FakeStack *t = fake_stack_;
 106     fake_stack_ = nullptr;
 107     SetTLSFakeStack(nullptr);
 108     t->Destroy(tid);
 109   }
 110
 111   void StartSwitchFiber(FakeStack **fake_stack_save, uptr bottom, uptr size);
 112   void FinishSwitchFiber(FakeStack *fake_stack_save, uptr *bottom_old,
 113                          uptr *size_old);
 114
 115   FakeStack *get_fake_stack() {
 116     if (atomic_load(&stack_switching_, memory_order_relaxed))
 117       return nullptr;
 118     if (reinterpret_cast<uptr>(fake_stack_) <= 1)
 119       return nullptr;
 120     return fake_stack_;
 121   }
 122
 123   FakeStack *get_or_create_fake_stack() {
 124     if (atomic_load(&stack_switching_, memory_order_relaxed))
 125       return nullptr;
 126     if (reinterpret_cast<uptr>(fake_stack_) <= 1)
 127       return AsyncSignalSafeLazyInitFakeStack();
 128     return fake_stack_;
 129   }
 130
 131   // True is this thread is currently unwinding stack (i.e. collecting a stack
 132   // trace). Used to prevent deadlocks on platforms where libc unwinder calls
 133   // malloc internally. See PR17116 for more details.
 134   bool isUnwinding() const { return unwinding_; }
 135   void setUnwinding(bool b) { unwinding_ = b; }
 136
 137   AsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; }
 138   AsanStats &stats() { return stats_; }
 139
 140   void *extra_spill_area() { return &extra_spill_area_; }
 141
 142   template <typename T>
 143   void GetStartData(T &data) const {
 144     GetStartData(&data, sizeof(data));
 145   }
 146
 147  private:
 148   // NOTE: There is no AsanThread constructor. It is allocated
 149   // via mmap() and *must* be valid in zero-initialized state.
 150
 151   static AsanThread *Create(const void *start_data, uptr data_size,
 152                             u32 parent_tid, StackTrace *stack, bool detached);
 153
 154   void SetThreadStackAndTls(const InitOptions *options);
 155
 156   void ClearShadowForThreadStackAndTLS();
 157   FakeStack *AsyncSignalSafeLazyInitFakeStack();
 158
 159   struct StackBounds {
 160     uptr bottom;
 161     uptr top;
 162   };
 163   StackBounds GetStackBounds() const;
 164
 165   void GetStartData(void *out, uptr out_size) const;
 166
 167   AsanThreadContext *context_;
 168
 169   uptr stack_top_;
 170   uptr stack_bottom_;
 171   // these variables are used when the thread is about to switch stack
 172   uptr next_stack_top_;
 173   uptr next_stack_bottom_;
 174   // true if switching is in progress
 175   atomic_uint8_t stack_switching_;
 176
 177   uptr tls_begin_;
 178   uptr tls_end_;
 179   DTLS *dtls_;
 180
 181   FakeStack *fake_stack_;
 182   AsanThreadLocalMallocStorage malloc_storage_;
 183   AsanStats stats_;
 184   bool unwinding_;
 185   uptr extra_spill_area_;
 186
 187   char start_data_[];
 188 };
 189
 190 #if defined(_MSC_VER) && !defined(__clang__)
 191 #  pragma warning(pop)
 192 #endif
 193
 194 // Returns a single instance of registry.
 195 ThreadRegistry &asanThreadRegistry();
 196 ThreadArgRetval &asanThreadArgRetval();
 197
 198 // Must be called under ThreadRegistryLock.
 199 AsanThreadContext *GetThreadContextByTidLocked(u32 tid);
 200
 201 // Get the current thread. May return 0.
 202 AsanThread *GetCurrentThread();
 203 void SetCurrentThread(AsanThread *t);
 204 u32 GetCurrentTidOrInvalid();
 205 AsanThread *FindThreadByStackAddress(uptr addr);
 206
 207 // Used to handle fork().
 208 void EnsureMainThreadIDIsCorrect();
 209 } // namespace __asan
 210
 211 #endif // ASAN_THREAD_H