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
21inline constexpr bool G_FUZZING_BUILD{
22#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
23    true
24#else
25    false
26#endif
27};
28inline 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
36extern std::atomic<bool> g_enable_dynamic_fuzz_determinism;
37
38inline 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
53extern bool g_detail_test_only_CheckFailuresAreExceptionsNotAborts;
54struct 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
59std::string StrFormatInternalBug(std::string_view msg, const std::source_location& loc);
60
61class NonFatalCheckError : public std::runtime_error
62{
63public:
64    NonFatalCheckError(std::string_view msg, const std::source_location& loc);
65};
66
67/// Internal helper. The noreturn enables optimizers to discard invalid paths.
68[[noreturn]] void assertion_fail(const std::source_location& loc, std::string_view assertion);
69
70/** Helper for CHECK_NONFATAL() */
71template <typename T>
72T&& 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() */
88template <bool IS_ASSERT, typename T>
89constexpr 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
148