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