1  // Copyright (c) 2019-present The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  
  5  #ifndef BITCOIN_UTIL_CHECK_H
  6  #define BITCOIN_UTIL_CHECK_H
  7  
  8  #include <attributes.h>
  9  
 10  #include <atomic>
 11  // We use `util/check.h` to provide the `assert()` macro
 12  // to ensure that `NDEBUG` is not defined.
 13  #include <cassert> // IWYU pragma: export
 14  #include <source_location>
 15  #include <stdexcept>
 16  #include <string>
 17  #include <string_view>
 18  #include <type_traits>
 19  #include <utility>
 20  
 21  constexpr bool G_FUZZING_BUILD{
 22  #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 23      true
 24  #else
 25      false
 26  #endif
 27  };
 28  constexpr bool G_ABORT_ON_FAILED_ASSUME{G_FUZZING_BUILD ||
 29  #ifdef ABORT_ON_FAILED_ASSUME
 30      true
 31  #else
 32      false
 33  #endif
 34  };
 35  
 36  extern std::atomic<bool> g_enable_dynamic_fuzz_determinism;
 37  
 38  inline bool EnableFuzzDeterminism()
 39  {
 40      if constexpr (G_FUZZING_BUILD) {
 41          return true;
 42      } else if constexpr (!G_ABORT_ON_FAILED_ASSUME) {
 43          // Running fuzz tests is always disabled if Assume() doesn't abort
 44          // (ie, non-fuzz non-debug builds), as otherwise tests which
 45          // should fail due to a failing Assume may still pass. As such,
 46          // we also statically disable fuzz determinism in that case.
 47          return false;
 48      } else {
 49          return g_enable_dynamic_fuzz_determinism;
 50      }
 51  }
 52  
 53  extern bool g_detail_test_only_CheckFailuresAreExceptionsNotAborts;
 54  struct test_only_CheckFailuresAreExceptionsNotAborts {
 55      test_only_CheckFailuresAreExceptionsNotAborts() { g_detail_test_only_CheckFailuresAreExceptionsNotAborts = true; };
 56      ~test_only_CheckFailuresAreExceptionsNotAborts() { g_detail_test_only_CheckFailuresAreExceptionsNotAborts = false; };
 57  };
 58  
 59  std::string StrFormatInternalBug(std::string_view msg, const std::source_location& loc);
 60  
 61  class NonFatalCheckError : public std::runtime_error
 62  {
 63  public:
 64      NonFatalCheckError(std::string_view msg, const std::source_location& loc);
 65  };
 66  
 67  /** Internal helper */
 68  void assertion_fail(const std::source_location& loc, std::string_view assertion);
 69  
 70  /** Helper for CHECK_NONFATAL() */
 71  template <typename T>
 72  T&& inline_check_non_fatal(LIFETIMEBOUND T&& val, const std::source_location& loc, std::string_view assertion)
 73  {
 74      if (!val) {
 75          if constexpr (G_ABORT_ON_FAILED_ASSUME) {
 76              assertion_fail(loc, assertion);
 77          }
 78          throw NonFatalCheckError{assertion, loc};
 79      }
 80      return std::forward<T>(val);
 81  }
 82  
 83  #if defined(NDEBUG)
 84  #error "Cannot compile without assertions!"
 85  #endif
 86  
 87  /** Helper for Assert()/Assume() */
 88  template <bool IS_ASSERT, typename T>
 89  constexpr T&& inline_assertion_check(LIFETIMEBOUND T&& val, [[maybe_unused]] const std::source_location& loc, [[maybe_unused]] std::string_view assertion)
 90  {
 91      if (IS_ASSERT || std::is_constant_evaluated() || G_ABORT_ON_FAILED_ASSUME) {
 92          if (!val) {
 93              assertion_fail(loc, assertion);
 94          }
 95      }
 96      return std::forward<T>(val);
 97  }
 98  
 99  #define STR_INTERNAL_BUG(msg) StrFormatInternalBug((msg), std::source_location::current())
100  
101  /**
102   * Identity function. Throw a NonFatalCheckError when the condition evaluates to false
103   *
104   * This should only be used
105   * - where the condition is assumed to be true, not for error handling or validating user input
106   * - where a failure to fulfill the condition is recoverable and does not abort the program
107   *
108   * For example in RPC code, where it is undesirable to crash the whole program, this can be generally used to replace
109   * asserts or recoverable logic errors. A NonFatalCheckError in RPC code is caught and passed as a string to the RPC
110   * caller, which can then report the issue to the developers.
111   */
112  #define CHECK_NONFATAL(condition) \
113      inline_check_non_fatal(condition, std::source_location::current(), #condition)
114  
115  /** Identity function. Abort if the value compares equal to zero */
116  #define Assert(val) inline_assertion_check<true>(val, std::source_location::current(), #val)
117  
118  /**
119   * Assume is the identity function.
120   *
121   * - Should be used to run non-fatal checks. In debug builds it behaves like
122   *   Assert()/assert() to notify developers and testers about non-fatal errors.
123   *   In production it doesn't warn or log anything.
124   * - For fatal errors, use Assert().
125   * - For non-fatal errors in interactive sessions (e.g. RPC or command line
126   *   interfaces), CHECK_NONFATAL() might be more appropriate.
127   */
128  #define Assume(val) inline_assertion_check<false>(val, std::source_location::current(), #val)
129  
130  /**
131   * NONFATAL_UNREACHABLE() is a macro that is used to mark unreachable code. It throws a NonFatalCheckError.
132   */
133  #define NONFATAL_UNREACHABLE() \
134      throw NonFatalCheckError { "Unreachable code reached (non-fatal)", std::source_location::current() }
135  
136  #if defined(__has_feature)
137  #    if __has_feature(address_sanitizer)
138  #       include <sanitizer/asan_interface.h>
139  #    endif
140  #endif
141  
142  #ifndef ASAN_POISON_MEMORY_REGION
143  #   define ASAN_POISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
144  #   define ASAN_UNPOISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
145  #endif
146  
147  #endif // BITCOIN_UTIL_CHECK_H