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1 : : // Copyright (c) 2009-2010 Satoshi Nakamoto
2 : : // Copyright (c) 2009-2022 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 <chainparams.h>
10 : : #include <kernel/chainparams.h>
11 : : #include <kernel/cs_main.h>
12 : : #include <serialize.h>
13 : : #include <sync.h>
14 : : #include <uint256.h>
15 : : #include <util/chaintype.h>
16 : : #include <util/check.h>
17 : : #include <util/fs.h>
18 : :
19 : : #include <cstdint>
20 : : #include <optional>
21 : : #include <string_view>
22 : :
23 : : // UTXO set snapshot magic bytes
24 : : static constexpr std::array<uint8_t, 5> SNAPSHOT_MAGIC_BYTES = {'u', 't', 'x', 'o', 0xff};
25 : :
26 : : class Chainstate;
27 : :
28 : : namespace node {
29 : : //! Metadata describing a serialized version of a UTXO set from which an
30 : : //! assumeutxo Chainstate can be constructed.
31 : : //! All metadata fields come from an untrusted file, so must be validated
32 : : //! before being used. Thus, new fields should be added only if needed.
33 : 66 : class SnapshotMetadata
34 : : {
35 : : inline static const uint16_t VERSION{2};
36 : : const std::set<uint16_t> m_supported_versions{VERSION};
37 : : const MessageStartChars m_network_magic;
38 : : public:
39 : : //! The hash of the block that reflects the tip of the chain for the
40 : : //! UTXO set contained in this snapshot.
41 : : uint256 m_base_blockhash;
42 : :
43 : :
44 : : //! The number of coins in the UTXO set contained in this snapshot. Used
45 : : //! during snapshot load to estimate progress of UTXO set reconstruction.
46 : : uint64_t m_coins_count = 0;
47 : :
48 : 33 : SnapshotMetadata(
49 : 33 : const MessageStartChars network_magic) :
50 : 33 : m_network_magic(network_magic) { }
51 : 33 : SnapshotMetadata(
52 : : const MessageStartChars network_magic,
53 : : const uint256& base_blockhash,
54 : 33 : uint64_t coins_count) :
55 : 33 : m_network_magic(network_magic),
56 : 33 : m_base_blockhash(base_blockhash),
57 : 33 : m_coins_count(coins_count) { }
58 : :
59 : : template <typename Stream>
60 : 33 : inline void Serialize(Stream& s) const {
61 : 33 : s << SNAPSHOT_MAGIC_BYTES;
62 : 33 : s << VERSION;
63 : 33 : s << m_network_magic;
64 : 33 : s << m_base_blockhash;
65 : 33 : s << m_coins_count;
66 : 33 : }
67 : :
68 : : template <typename Stream>
69 : 33 : inline void Unserialize(Stream& s) {
70 : : // Read the snapshot magic bytes
71 : : std::array<uint8_t, SNAPSHOT_MAGIC_BYTES.size()> snapshot_magic;
72 [ - + ]: 33 : s >> snapshot_magic;
73 [ - + ]: 33 : if (snapshot_magic != SNAPSHOT_MAGIC_BYTES) {
74 [ # # ]: 0 : 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.");
75 : : }
76 : :
77 : : // Read the version
78 : : uint16_t version;
79 : 33 : s >> version;
80 [ - + ]: 33 : if (m_supported_versions.find(version) == m_supported_versions.end()) {
81 [ # # # # ]: 0 : throw std::ios_base::failure(strprintf("Version of snapshot %s does not match any of the supported versions.", version));
82 : : }
83 : :
84 : : // Read the network magic (pchMessageStart)
85 : : MessageStartChars message;
86 : 33 : s >> message;
87 [ - + ]: 33 : if (!std::equal(message.begin(), message.end(), m_network_magic.data())) {
88 [ # # ]: 0 : auto metadata_network{GetNetworkForMagic(message)};
89 [ # # ]: 0 : if (metadata_network) {
90 : 0 : std::string network_string{ChainTypeToString(metadata_network.value())};
91 [ # # ]: 0 : auto node_network{GetNetworkForMagic(m_network_magic)};
92 [ # # ]: 0 : std::string node_network_string{ChainTypeToString(node_network.value())};
93 [ # # # # ]: 0 : 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));
94 : 0 : } else {
95 [ # # ]: 0 : 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.");
96 : : }
97 : : }
98 : :
99 : 33 : s >> m_base_blockhash;
100 : 33 : s >> m_coins_count;
101 : 33 : }
102 : : };
103 : :
104 : : //! The file in the snapshot chainstate dir which stores the base blockhash. This is
105 : : //! needed to reconstruct snapshot chainstates on init.
106 : : //!
107 : : //! Because we only allow loading a single snapshot at a time, there will only be one
108 : : //! chainstate directory with this filename present within it.
109 : : const fs::path SNAPSHOT_BLOCKHASH_FILENAME{"base_blockhash"};
110 : :
111 : : //! Write out the blockhash of the snapshot base block that was used to construct
112 : : //! this chainstate. This value is read in during subsequent initializations and
113 : : //! used to reconstruct snapshot-based chainstates.
114 : : bool WriteSnapshotBaseBlockhash(Chainstate& snapshot_chainstate)
115 : : EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
116 : :
117 : : //! Read the blockhash of the snapshot base block that was used to construct the
118 : : //! chainstate.
119 : : std::optional<uint256> ReadSnapshotBaseBlockhash(fs::path chaindir)
120 : : EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
121 : :
122 : : //! Suffix appended to the chainstate (leveldb) dir when created based upon
123 : : //! a snapshot.
124 : : constexpr std::string_view SNAPSHOT_CHAINSTATE_SUFFIX = "_snapshot";
125 : :
126 : :
127 : : //! Return a path to the snapshot-based chainstate dir, if one exists.
128 : : std::optional<fs::path> FindSnapshotChainstateDir(const fs::path& data_dir);
129 : :
130 : : } // namespace node
131 : :
132 : : #endif // BITCOIN_NODE_UTXO_SNAPSHOT_H
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