pallet_evm_precompile_registry/
lib.rs

1// Copyright 2019-2025 PureStake Inc.
2// This file is part of Moonbeam.
3
4// Moonbeam is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8
9// Moonbeam is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13
14// You should have received a copy of the GNU General Public License
15// along with Moonbeam.  If not, see <http://www.gnu.org/licenses/>.
16
17#![cfg_attr(not(feature = "std"), no_std)]
18
19#[cfg(test)]
20mod mock;
21#[cfg(test)]
22mod tests;
23
24use core::marker::PhantomData;
25use fp_evm::{ExitError, IsPrecompileResult, PrecompileFailure};
26use precompile_utils::{
27	precompile_set::{is_precompile_or_fail, IsActivePrecompile},
28	prelude::*,
29};
30use sp_core::Get;
31
32const DUMMY_CODE: [u8; 5] = [0x60, 0x00, 0x60, 0x00, 0xfd];
33
34pub struct PrecompileRegistry<Runtime>(PhantomData<Runtime>);
35
36#[precompile_utils::precompile]
37impl<Runtime> PrecompileRegistry<Runtime>
38where
39	Runtime: pallet_evm::Config,
40	Runtime::PrecompilesType: IsActivePrecompile,
41{
42	#[precompile::public("isPrecompile(address)")]
43	#[precompile::view]
44	fn is_precompile(handle: &mut impl PrecompileHandle, address: Address) -> EvmResult<bool> {
45		// We consider the precompile set is optimized to do at most one storage read.
46		// In the case of moonbeam, the storage item that can be read is pallet_asset::Asset
47		// (TODO make it more generic, maybe add a const generic on PrecompileRegistry type)
48		// Storage item: Asset:
49		// Blake2_128(16) + AssetId(16) + AssetDetails((4 * AccountId(20)) + (3 * Balance(16)) + 15)
50		handle.record_db_read::<Runtime>(175)?;
51		is_precompile_or_fail::<Runtime>(address.0, handle.remaining_gas())
52	}
53
54	#[precompile::public("isActivePrecompile(address)")]
55	#[precompile::view]
56	fn is_active_precompile(
57		handle: &mut impl PrecompileHandle,
58		address: Address,
59	) -> EvmResult<bool> {
60		// We consider the precompile set is optimized to do at most one storage read.
61		// In the case of moonbeam, the storage item that can be read is pallet_asset::Asset
62		// (TODO make it more generic, maybe add a const generic on PrecompileRegistry type)
63		// Storage item: Asset:
64		// Blake2_128(16) + AssetId(16) + AssetDetails((4 * AccountId(20)) + (3 * Balance(16)) + 15)
65		handle.record_db_read::<Runtime>(175)?;
66		match <Runtime::PrecompilesValue>::get()
67			.is_active_precompile(address.0, handle.remaining_gas())
68		{
69			IsPrecompileResult::Answer { is_precompile, .. } => Ok(is_precompile),
70			IsPrecompileResult::OutOfGas => Err(PrecompileFailure::Error {
71				exit_status: ExitError::OutOfGas,
72			}),
73		}
74	}
75
76	#[precompile::public("updateAccountCode(address)")]
77	fn update_account_code(handle: &mut impl PrecompileHandle, address: Address) -> EvmResult<()> {
78		// Prevent touching addresses that are not precompiles.
79		//
80		// We consider the precompile set is optimized to do at most one storage read.
81		// In the case of moonbeam, the storage item that can be read is pallet_asset::Asset
82		// (TODO make it more generic, maybe add a const generic on PrecompileRegistry type)
83		// Storage item: Asset:
84		// Blake2_128(16) + AssetId(16) + AssetDetails((4 * AccountId(20)) + (3 * Balance(16)) + 15)
85		handle.record_db_read::<Runtime>(175)?;
86		if !is_precompile_or_fail::<Runtime>(address.0, handle.remaining_gas())? {
87			return Err(revert("provided address is not a precompile"));
88		}
89
90		// pallet_evm::create_account read storage item pallet_evm::AccountCodes
91		//
92		// AccountCodes: Blake2128(16) + H160(20) + Vec(5)
93		// We asume an existing precompile can hold at most 5 bytes worth of dummy code.
94		handle.record_db_read::<Runtime>(41)?;
95		pallet_evm::Pallet::<Runtime>::create_account(address.0, DUMMY_CODE.to_vec(), None)
96			.map_err(|e| PrecompileFailure::Error { exit_status: e })?;
97
98		Ok(())
99	}
100}
pallet_evm_precompile_registry/lib.rs

pallet_evm_precompile_registry/
lib.rs
