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//! SputnikVM implementation, traits and structs. //! //! SputnikVM works on two different levels. It handles: //! 1. a transaction, or //! 2. an Ethereum execution context. //! //! To interact with the virtual machine, you usually only need to //! work with [VM](trait.VM.html) methods. //! //! ### A SputnikVM's Lifecycle //! //! A VM can be started after it is given a `Transaction` (or //! `Context`) and a `BlockHeader`. The user can then `fire` or `step` //! to run it. [`fire`](trait.VM.html#method.fire) runs the EVM code //! (given in field `code` of the transaction) until it finishes or //! cannot continue. However [`step`](trait.VM.html#tymethod.step) //! only runs at most one instruction. If the virtual machine needs //! some information (accounts in the current block, or block hashes //! of previous blocks) it fails, returning a //! [`RequireError`](errors/enum.RequireError.html) enumeration. With //! the data returned in the `RequireError` enumeration, one can use //! the methods //! [`commit_account`](trait.VM.html#tymethod.commit_account) and //! [`commit_blockhash`](trait.VM.html#tymethod.commit_blockhash) to //! commit the information to the VM. `fire` or `step` can be //! subsequently called to restart from that point. The current VM //! status can always be obtained using the `status` function. Again, //! see [VM](trait.VM.html) for a list of methods that can be applied. //! //! ### Patch: Specifying a Network and Hard-fork //! //! Every VM is associated with a `Patch`. This patch tells the VM //! which Ethereum network and which hard fork it is on. You will need //! to specify the patch as the type parameter. To interact with //! multiple patches at the same time, it is recommended that you use //! trait objects. //! //! The example below creates a new SputnikVM and stores the object in //! `vm` which can be used to `fire`, `step` or get status on. To do //! this, it must first create a transaction and a block header. The //! patch associated with the VM is either `EmbeddedPatch` or //! `VMTestPatch` depending on an arbitrary block number value set at //! the beginning of the program. //! //! ``` //! use evm::{EmbeddedPatch, VMTestPatch, //! HeaderParams, ValidTransaction, TransactionAction, //! VM, SeqTransactionVM}; //! use bigint::{Gas, U256, Address}; //! use std::rc::Rc; //! //! fn main() { //! let block_number = 1000; //! let transaction = ValidTransaction { //! caller: Some(Address::default()), //! gas_price: Gas::zero(), //! gas_limit: Gas::max_value(), //! action: TransactionAction::Create, //! value: U256::zero(), //! input: Rc::new(Vec::new()), //! nonce: U256::zero() //! }; //! let header = HeaderParams { //! beneficiary: Address::default(), //! timestamp: 0, //! number: U256::zero(), //! difficulty: U256::zero(), //! gas_limit: Gas::zero() //! }; //! let cfg_before_500 = VMTestPatch::default(); //! let cfg_after_500 = EmbeddedPatch::default(); //! let vm = if block_number < 500 { //! SeqTransactionVM::new( //! &cfg_before_500, //! transaction, //! header //! ); //! } else { //! SeqTransactionVM::new( //! &cfg_after_500, //! transaction, //! header //! ); //! }; //! } //! ``` //! //! ### Transaction Execution //! //! To start a VM on the Transaction level, use the `TransactionVM` //! struct. Usually, you want to use the sequential memory module //! which can be done using the type definition //! `SeqTransactionVM`. //! //! Calling `TransactionVM::new` or `SeqTransactionVM::new` requires //! the transaction passed in to be valid (according to the rules for //! an Ethereum transaction). If the transaction is invalid, the VM //! will probably panic. If you want to handle untrusted transactions, //! you should use `SeqTransactionVM::new_untrusted`, which will not //! panic but instead return an error if the transaction is invalid. //! //! ### Context Execution //! //! To start a VM on the Context level, use the `ContextVM` //! struct. Usually, you use the sequential memory module with the //! type definition `SeqContextVM`. Context execution, as with other //! EVM implementations, will not handle transaction-level gas //! reductions. #![deny( unused_import_braces, unused_imports, unused_comparisons, unused_must_use, unused_variables, non_shorthand_field_patterns, unreachable_code, missing_docs )] #![cfg_attr(not(feature = "std"), no_std)] #![cfg_attr(not(feature = "std"), feature(alloc))] // extern crates below are left in code on purpose even though it's discouraged in Edition 2018 // in the event of incorrect feature setting, the error will pop up on // extern crate statement in lib.rs, which is easier to debug #[cfg(not(feature = "std"))] extern crate alloc; #[cfg(feature = "c-secp256k1")] extern crate secp256k1; #[cfg(feature = "rust-secp256k1")] extern crate secp256k1; #[cfg(feature = "std")] extern crate block; // BUG: without old-style #[macro_use] extern crate, evm-rs cannot be compiled as a dependency. #[macro_use] extern crate log; mod commit; pub mod errors; mod eval; mod memory; mod params; mod patch; mod pc; mod stack; mod transaction; mod util; pub use crate::commit::{AccountChange, AccountCommitment, AccountState, BlockhashState, Storage}; pub use crate::errors::{CommitError, NotSupportedError, OnChainError, PreExecutionError, RequireError}; pub use crate::eval::{Machine, MachineStatus, Runtime, State}; pub use crate::memory::{Memory, SeqMemory}; pub use crate::params::*; pub use crate::patch::*; pub use crate::pc::{Instruction, PCMut, Valids, PC}; pub use crate::stack::Stack; pub use crate::transaction::{TransactionVM, UntrustedTransaction, ValidTransaction}; pub use crate::util::opcode::Opcode; pub use block_core::TransactionAction; #[cfg(not(feature = "std"))] use alloc::vec::Vec; #[cfg(not(feature = "std"))] use alloc::boxed::Box; #[cfg(not(feature = "std"))] use alloc::{collections::btree_map as map, collections::BTreeSet as Set}; use bigint::{Address, Gas, H256, U256}; #[cfg(not(feature = "std"))] use core::cmp::min; #[cfg(feature = "std")] use std::cmp::min; #[cfg(feature = "std")] use std::collections::{hash_map as map, HashSet as Set}; #[derive(Debug, Clone, PartialEq)] /// VM Status pub enum VMStatus { /// A running VM. Running, /// VM is stopped without errors. ExitedOk, /// VM is stopped due to an error. The state of the VM is before /// the last failing instruction. ExitedErr(OnChainError), /// VM is stopped because it does not support certain /// operations. The client is expected to either drop the /// transaction or panic. This rarely happens unless the executor /// agrees upon on a really large number of gas limit, so it /// usually can be safely ignored. ExitedNotSupported(NotSupportedError), } /// Represents an EVM. This is usually the main interface for clients /// to interact with. pub trait VM { /// Commit an account information to this VM. This should only /// be used when receiving `RequireError`. fn commit_account(&mut self, commitment: AccountCommitment) -> Result<(), CommitError>; /// Commit a block hash to this VM. This should only be used when /// receiving `RequireError`. fn commit_blockhash(&mut self, number: U256, hash: H256) -> Result<(), CommitError>; /// Returns the current status of the VM. fn status(&self) -> VMStatus; /// Read the next instruction to be executed. fn peek(&self) -> Option<Instruction>; /// Read the next opcode to be executed. fn peek_opcode(&self) -> Option<Opcode>; /// Run one instruction and return. If it succeeds, VM status can /// still be `Running`. If the call stack has more than one items, /// this will only executes the last items' one single /// instruction. fn step(&mut self) -> Result<(), RequireError>; /// Run instructions until it reaches a `RequireError` or /// exits. If this function succeeds, the VM status can only be /// either `ExitedOk` or `ExitedErr`. fn fire(&mut self) -> Result<(), RequireError> { loop { match self.status() { VMStatus::Running => self.step()?, VMStatus::ExitedOk | VMStatus::ExitedErr(_) | VMStatus::ExitedNotSupported(_) => return Ok(()), } } } /// Returns the changed or committed accounts information up to /// current execution status. fn accounts(&self) -> map::Values<Address, AccountChange>; /// Returns all fetched or modified addresses. fn used_addresses(&self) -> Set<Address>; /// Returns the out value, if any. fn out(&self) -> &[u8]; /// Returns the available gas of this VM. fn available_gas(&self) -> Gas; /// Returns the refunded gas of this VM. fn refunded_gas(&self) -> Gas; /// Returns logs to be appended to the current block if the user /// decided to accept the running status of this VM. fn logs(&self) -> &[Log]; /// Returns all removed account addresses as for current VM execution. fn removed(&self) -> &[Address]; /// Returns the real used gas by the transaction or the VM /// context. Only available when the status of the VM is /// exited. Otherwise returns zero. fn used_gas(&self) -> Gas; } /// A sequential VM. It uses sequential memory representation and hash /// map storage for accounts. pub type SeqContextVM<'a, P> = ContextVM<'a, SeqMemory, P>; /// A sequential transaction VM. This is same as `SeqContextVM` except /// it runs at transaction level. pub type SeqTransactionVM<'a, P> = TransactionVM<'a, SeqMemory, P>; /// A VM that executes using a context and block information. pub struct ContextVM<'a, M, P: Patch> { runtime: Runtime, machines: Vec<Machine<'a, M, P>>, fresh_account_state: AccountState<'a, P::Account>, } impl<'a, M: Memory, P: Patch> ContextVM<'a, M, P> { /// Create a new VM using the given context, block header and patch. pub fn new(patch: &'a P, context: Context, block: HeaderParams) -> Self { let mut machines = Vec::new(); let account_patch = patch.account_patch(); machines.push(Machine::new(patch, context, 1)); ContextVM { machines, runtime: Runtime::new(block), fresh_account_state: AccountState::new(account_patch), } } /// Create a new VM with the given account state and blockhash state. pub fn with_states( patch: &'a P, context: Context, block: HeaderParams, account_state: AccountState<'a, P::Account>, blockhash_state: BlockhashState, ) -> Self { let mut machines = Vec::new(); machines.push(Machine::with_states(patch, context, 1, account_state.clone())); ContextVM { machines, runtime: Runtime::with_states(block, blockhash_state), fresh_account_state: account_state, } } /// Create a new VM with customized initialization code. pub fn with_init<F: FnOnce(&mut ContextVM<M, P>)>( patch: &'a P, context: Context, block: HeaderParams, account_state: AccountState<'a, P::Account>, blockhash_state: BlockhashState, f: F, ) -> Self { let mut vm = Self::with_states(patch, context, block, account_state, blockhash_state); f(&mut vm); vm.fresh_account_state = AccountState::derive_from(patch.account_patch(), &vm.machines[0].state().account_state); vm } /// Create a new VM with the result of the previous VM. This is /// usually used by transaction for chainning them. pub fn with_previous(patch: &'a P, context: Context, block: HeaderParams, vm: &'a ContextVM<'a, M, P>) -> Self { Self::with_states( patch, context, block, vm.machines[0].state().account_state.clone(), vm.runtime.blockhash_state.clone(), ) } /// Returns the current state of the VM. pub fn current_state(&self) -> &State<M, P> { self.current_machine().state() } /// Returns the current runtime machine. pub fn current_machine(&self) -> &Machine<M, P> { self.machines.last().unwrap() } /// Add a new context history hook. pub fn add_context_history_hook<F: 'static + Fn(&Context)>(&mut self, f: F) { self.runtime.context_history_hooks.push(Box::new(f)); debug!("registered a new history hook"); } } impl<'a, M: Memory, P: Patch> VM for ContextVM<'a, M, P> { fn commit_account(&mut self, commitment: AccountCommitment) -> Result<(), CommitError> { for machine in &mut self.machines { machine.commit_account(commitment.clone())?; } debug!("committed account info: {:?}", commitment); Ok(()) } fn commit_blockhash(&mut self, number: U256, hash: H256) -> Result<(), CommitError> { self.runtime.blockhash_state.commit(number, hash)?; debug!("committed blockhash number {}: {}", number, hash); Ok(()) } #[allow(clippy::single_match)] fn status(&self) -> VMStatus { match self.machines.last().unwrap().status().clone() { MachineStatus::ExitedNotSupported(err) => return VMStatus::ExitedNotSupported(err), _ => (), } match self.machines[0].status() { MachineStatus::Running | MachineStatus::InvokeCreate(_) | MachineStatus::InvokeCall(_, _) => { VMStatus::Running } MachineStatus::ExitedOk => VMStatus::ExitedOk, MachineStatus::ExitedErr(err) => VMStatus::ExitedErr(err), MachineStatus::ExitedNotSupported(err) => VMStatus::ExitedNotSupported(err), } } fn peek(&self) -> Option<Instruction> { match self.machines.last().unwrap().status().clone() { MachineStatus::Running => self.machines.last().unwrap().peek(), _ => None, } } fn peek_opcode(&self) -> Option<Opcode> { match self.machines.last().unwrap().status().clone() { MachineStatus::Running => self.machines.last().unwrap().peek_opcode(), _ => None, } } fn step(&mut self) -> Result<(), RequireError> { match self.machines.last().unwrap().status().clone() { MachineStatus::Running => { self.machines.last_mut().unwrap().step(&self.runtime)?; if self.machines.len() == 1 { match self.machines.last().unwrap().status().clone() { MachineStatus::ExitedOk | MachineStatus::ExitedErr(_) => self .machines .last_mut() .unwrap() .finalize_context(&self.fresh_account_state), _ => (), } } Ok(()) } MachineStatus::ExitedOk | MachineStatus::ExitedErr(_) => { if self.machines.is_empty() { panic!() } else if self.machines.len() == 1 { Ok(()) } else { let finished = self.machines.pop().unwrap(); self.machines.last_mut().unwrap().apply_sub(finished); Ok(()) } } MachineStatus::ExitedNotSupported(_) => Ok(()), MachineStatus::InvokeCall(context, _) => { for hook in &self.runtime.context_history_hooks { hook(&context) } let mut sub = self.machines.last().unwrap().derive(context); sub.invoke_call()?; self.machines.push(sub); Ok(()) } MachineStatus::InvokeCreate(context) => { for hook in &self.runtime.context_history_hooks { hook(&context) } let mut sub = self.machines.last().unwrap().derive(context); sub.invoke_create()?; self.machines.push(sub); Ok(()) } } } fn fire(&mut self) -> Result<(), RequireError> { loop { debug!("machines status:"); for (n, machine) in self.machines.iter().enumerate() { debug!("Machine {}: {:x?}", n, machine.status()); } match self.status() { VMStatus::Running => self.step()?, VMStatus::ExitedOk | VMStatus::ExitedErr(_) | VMStatus::ExitedNotSupported(_) => return Ok(()), } } } fn accounts(&self) -> map::Values<Address, AccountChange> { self.machines[0].state().account_state.accounts() } fn used_addresses(&self) -> Set<Address> { self.machines[0].state().account_state.used_addresses() } fn out(&self) -> &[u8] { self.machines[0].state().out.as_slice() } fn available_gas(&self) -> Gas { self.machines[0].state().available_gas() } fn refunded_gas(&self) -> Gas { self.machines[0].state().refunded_gas } fn logs(&self) -> &[Log] { self.machines[0].state().logs.as_slice() } fn removed(&self) -> &[Address] { self.machines[0].state().removed.as_slice() } fn used_gas(&self) -> Gas { let total_used = self.machines[0].state().total_used_gas(); let refund_cap = total_used / Gas::from(2u64); let refunded = min(refund_cap, self.machines[0].state().refunded_gas); total_used - refunded } }