Merge bitcoin/bitcoin#22322: fuzz: Check banman roundtrip

fa485d0 fuzz: Check banman roundtrip (MarcoFalke)

Pull request description:

ACKs for top commit:
  practicalswift:
    cr ACK fa485d0
  vasild:
    ACK fa485d0

Tree-SHA512: 84e297c0b90ef68d72afd2053bfda2888496c1b180233516a8caaf76d6c03403f1e4ed59f1eb32d799873fc34009634b4ce372244b9d546d04626af41ac4d1d7

Author: MarcoFalke

src/test/fuzz/banman.cpp

@@ -32,6 +32,13 @@ void initialize_banman()
     static const auto testing_setup = MakeNoLogFileContext<>();
 }
 
+static bool operator==(const CBanEntry& lhs, const CBanEntry& rhs)
+{
+    return lhs.nVersion == rhs.nVersion &&
+           lhs.nCreateTime == rhs.nCreateTime &&
+           lhs.nBanUntil == rhs.nBanUntil;
+}
+
 FUZZ_TARGET_INIT(banman, initialize_banman)
 {
     // The complexity is O(N^2), where N is the input size, because each call
@@ -43,19 +50,20 @@ FUZZ_TARGET_INIT(banman, initialize_banman)
     fs::path banlist_file = gArgs.GetDataDirNet() / "fuzzed_banlist";
 
     const bool start_with_corrupted_banlist{fuzzed_data_provider.ConsumeBool()};
+    bool force_read_and_write_to_err{false};
     if (start_with_corrupted_banlist) {
         const std::string sfx{fuzzed_data_provider.ConsumeBool() ? ".dat" : ".json"};
         assert(WriteBinaryFile(banlist_file.string() + sfx,
                                fuzzed_data_provider.ConsumeRandomLengthString()));
     } else {
-        const bool force_read_and_write_to_err{fuzzed_data_provider.ConsumeBool()};
+        force_read_and_write_to_err = fuzzed_data_provider.ConsumeBool();
         if (force_read_and_write_to_err) {
             banlist_file = fs::path{"path"} / "to" / "inaccessible" / "fuzzed_banlist";
         }
     }
 
     {
-        BanMan ban_man{banlist_file, nullptr, ConsumeBanTimeOffset(fuzzed_data_provider)};
+        BanMan ban_man{banlist_file, /* client_interface */ nullptr, /* default_ban_time */ ConsumeBanTimeOffset(fuzzed_data_provider)};
         while (--limit_max_ops >= 0 && fuzzed_data_provider.ConsumeBool()) {
             CallOneOf(
                 fuzzed_data_provider,
@@ -93,6 +101,16 @@ FUZZ_TARGET_INIT(banman, initialize_banman)
                     ban_man.Discourage(ConsumeNetAddr(fuzzed_data_provider));
                 });
         }
+        if (!force_read_and_write_to_err) {
+            ban_man.DumpBanlist();
+            SetMockTime(ConsumeTime(fuzzed_data_provider));
+            banmap_t banmap;
+            ban_man.GetBanned(banmap);
+            BanMan ban_man_read{banlist_file, /* client_interface */ nullptr, /* default_ban_time */ 0};
+            banmap_t banmap_read;
+            ban_man_read.GetBanned(banmap_read);
+            assert(banmap == banmap_read);
+        }
     }
     fs::remove(banlist_file.string() + ".dat");
     fs::remove(banlist_file.string() + ".json");