1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-present The Bitcoin Core developers
3 // Distributed under the MIT software license, see the accompanying
4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 6 #ifndef BITCOIN_NODE_UTXO_SNAPSHOT_H
7 #define BITCOIN_NODE_UTXO_SNAPSHOT_H
8 9 #include <kernel/chainparams.h>
10 #include <kernel/cs_main.h>
11 #include <kernel/messagestartchars.h>
12 #include <sync.h>
13 #include <tinyformat.h>
14 #include <uint256.h>
15 #include <util/chaintype.h>
16 #include <util/fs.h>
17 18 #include <algorithm>
19 #include <array>
20 #include <cstdint>
21 #include <ios>
22 #include <optional>
23 #include <set>
24 #include <string>
25 #include <string_view>
26 27 // UTXO set snapshot magic bytes
28 static constexpr std::array<uint8_t, 5> SNAPSHOT_MAGIC_BYTES = {'u', 't', 'x', 'o', 0xff};
29 30 class Chainstate;
31 32 namespace node {
33 //! Metadata describing a serialized version of a UTXO set from which an
34 //! assumeutxo Chainstate can be constructed.
35 //! All metadata fields come from an untrusted file, so must be validated
36 //! before being used. Thus, new fields should be added only if needed.
37 class SnapshotMetadata
38 {
39 inline static const uint16_t VERSION{2};
40 const std::set<uint16_t> m_supported_versions{VERSION};
41 const MessageStartChars m_network_magic;
42 public:
43 //! The hash of the block that reflects the tip of the chain for the
44 //! UTXO set contained in this snapshot.
45 uint256 m_base_blockhash;
46 47 48 //! The number of coins in the UTXO set contained in this snapshot. Used
49 //! during snapshot load to estimate progress of UTXO set reconstruction.
50 uint64_t m_coins_count = 0;
51 52 SnapshotMetadata(
53 const MessageStartChars network_magic) :
54 m_network_magic(network_magic) { }
55 SnapshotMetadata(
56 const MessageStartChars network_magic,
57 const uint256& base_blockhash,
58 uint64_t coins_count) :
59 m_network_magic(network_magic),
60 m_base_blockhash(base_blockhash),
61 m_coins_count(coins_count) { }
62 63 template <typename Stream>
64 inline void Serialize(Stream& s) const {
65 s << SNAPSHOT_MAGIC_BYTES;
66 s << VERSION;
67 s << m_network_magic;
68 s << m_base_blockhash;
69 s << m_coins_count;
70 }
71 72 template <typename Stream>
73 inline void Unserialize(Stream& s) {
74 // Read the snapshot magic bytes
75 std::array<uint8_t, SNAPSHOT_MAGIC_BYTES.size()> snapshot_magic;
76 s >> snapshot_magic;
77 if (snapshot_magic != SNAPSHOT_MAGIC_BYTES) {
78 throw std::ios_base::failure("Invalid UTXO set snapshot magic bytes. Please check if this is indeed a snapshot file or if you are using an outdated snapshot format.");
79 }
80 81 // Read the version
82 uint16_t version;
83 s >> version;
84 if (!m_supported_versions.contains(version)) {
85 throw std::ios_base::failure(strprintf("Version of snapshot %s does not match any of the supported versions.", version));
86 }
87 88 // Read the network magic (pchMessageStart)
89 MessageStartChars message;
90 s >> message;
91 if (!std::equal(message.begin(), message.end(), m_network_magic.data())) {
92 auto metadata_network{GetNetworkForMagic(message)};
93 if (metadata_network) {
94 std::string network_string{ChainTypeToString(metadata_network.value())};
95 auto node_network{GetNetworkForMagic(m_network_magic)};
96 std::string node_network_string{ChainTypeToString(node_network.value())};
97 throw std::ios_base::failure(strprintf("The network of the snapshot (%s) does not match the network of this node (%s).", network_string, node_network_string));
98 } else {
99 throw std::ios_base::failure("This snapshot has been created for an unrecognized network. This could be a custom signet, a new testnet or possibly caused by data corruption.");
100 }
101 }
102 103 s >> m_base_blockhash;
104 s >> m_coins_count;
105 }
106 };
107 108 //! The file in the snapshot chainstate dir which stores the base blockhash. This is
109 //! needed to reconstruct snapshot chainstates on init.
110 //!
111 //! Because we only allow loading a single snapshot at a time, there will only be one
112 //! chainstate directory with this filename present within it.
113 const fs::path SNAPSHOT_BLOCKHASH_FILENAME{"base_blockhash"};
114 115 //! Write out the blockhash of the snapshot base block that was used to construct
116 //! this chainstate. This value is read in during subsequent initializations and
117 //! used to reconstruct snapshot-based chainstates.
118 bool WriteSnapshotBaseBlockhash(Chainstate& snapshot_chainstate)
119 EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
120 121 //! Read the blockhash of the snapshot base block that was used to construct the
122 //! chainstate.
123 std::optional<uint256> ReadSnapshotBaseBlockhash(fs::path chaindir)
124 EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
125 126 //! Suffix appended to the chainstate (leveldb) dir when created based upon
127 //! a snapshot.
128 constexpr std::string_view SNAPSHOT_CHAINSTATE_SUFFIX = "_snapshot";
129 130 131 //! Return a path to the snapshot-based chainstate dir, if one exists.
132 std::optional<fs::path> FindAssumeutxoChainstateDir(const fs::path& data_dir);
133 134 } // namespace node
135 136 #endif // BITCOIN_NODE_UTXO_SNAPSHOT_H
137