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Diffstat (limited to 'core/vm/interpreter.go')
| -rw-r--r-- | core/vm/interpreter.go | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go new file mode 100644 index 0000000..e23896a --- /dev/null +++ b/core/vm/interpreter.go @@ -0,0 +1,314 @@ +// Copyright 2014 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. + +package vm + +import ( + "fmt" + "hash" + "sync/atomic" + + "github.com/ava-labs/go-ethereum/common" + "github.com/ava-labs/go-ethereum/common/math" + "github.com/ava-labs/go-ethereum/log" +) + +var ( + BuiltinAddr = common.Address{ + 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + } +) + +// Config are the configuration options for the Interpreter +type Config struct { + Debug bool // Enables debugging + Tracer Tracer // Opcode logger + NoRecursion bool // Disables call, callcode, delegate call and create + EnablePreimageRecording bool // Enables recording of SHA3/keccak preimages + + JumpTable [256]operation // EVM instruction table, automatically populated if unset + + EWASMInterpreter string // External EWASM interpreter options + EVMInterpreter string // External EVM interpreter options + + ExtraEips []int // Additional EIPS that are to be enabled +} + +// Interpreter is used to run Ethereum based contracts and will utilise the +// passed environment to query external sources for state information. +// The Interpreter will run the byte code VM based on the passed +// configuration. +type Interpreter interface { + // Run loops and evaluates the contract's code with the given input data and returns + // the return byte-slice and an error if one occurred. + Run(contract *Contract, input []byte, static bool) ([]byte, error) + // CanRun tells if the contract, passed as an argument, can be + // run by the current interpreter. This is meant so that the + // caller can do something like: + // + // ```golang + // for _, interpreter := range interpreters { + // if interpreter.CanRun(contract.code) { + // interpreter.Run(contract.code, input) + // } + // } + // ``` + CanRun([]byte) bool +} + +// keccakState wraps sha3.state. In addition to the usual hash methods, it also supports +// Read to get a variable amount of data from the hash state. Read is faster than Sum +// because it doesn't copy the internal state, but also modifies the internal state. +type keccakState interface { + hash.Hash + Read([]byte) (int, error) +} + +// EVMInterpreter represents an EVM interpreter +type EVMInterpreter struct { + evm *EVM + cfg Config + + intPool *intPool + + hasher keccakState // Keccak256 hasher instance shared across opcodes + hasherBuf common.Hash // Keccak256 hasher result array shared aross opcodes + + readOnly bool // Whether to throw on stateful modifications + returnData []byte // Last CALL's return data for subsequent reuse +} + +// NewEVMInterpreter returns a new instance of the Interpreter. +func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter { + // We use the STOP instruction whether to see + // the jump table was initialised. If it was not + // we'll set the default jump table. + if !cfg.JumpTable[STOP].valid { + var jt JumpTable + switch { + case evm.chainRules.IsIstanbul: + jt = istanbulInstructionSet + case evm.chainRules.IsConstantinople: + jt = constantinopleInstructionSet + case evm.chainRules.IsByzantium: + jt = byzantiumInstructionSet + case evm.chainRules.IsEIP158: + jt = spuriousDragonInstructionSet + case evm.chainRules.IsEIP150: + jt = tangerineWhistleInstructionSet + case evm.chainRules.IsHomestead: + jt = homesteadInstructionSet + default: + jt = frontierInstructionSet + } + for i, eip := range cfg.ExtraEips { + if err := EnableEIP(eip, &jt); err != nil { + // Disable it, so caller can check if it's activated or not + cfg.ExtraEips = append(cfg.ExtraEips[:i], cfg.ExtraEips[i+1:]...) + log.Error("EIP activation failed", "eip", eip, "error", err) + } + } + cfg.JumpTable = jt + } + + return &EVMInterpreter{ + evm: evm, + cfg: cfg, + } +} + +// Run loops and evaluates the contract's code with the given input data and returns +// the return byte-slice and an error if one occurred. +// +// It's important to note that any errors returned by the interpreter should be +// considered a revert-and-consume-all-gas operation except for +// errExecutionReverted which means revert-and-keep-gas-left. +func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (ret []byte, err error) { + if contract.Address() == BuiltinAddr { + self := AccountRef(contract.Caller()) + if _, ok := contract.caller.(*Contract); ok { + contract = contract.AsDelegate() + } + contract.self = self + } + if in.intPool == nil { + in.intPool = poolOfIntPools.get() + defer func() { + poolOfIntPools.put(in.intPool) + in.intPool = nil + }() + } + + // Increment the call depth which is restricted to 1024 + in.evm.depth++ + defer func() { in.evm.depth-- }() + + // Make sure the readOnly is only set if we aren't in readOnly yet. + // This makes also sure that the readOnly flag isn't removed for child calls. + if readOnly && !in.readOnly { + in.readOnly = true + defer func() { in.readOnly = false }() + } + + // Reset the previous call's return data. It's unimportant to preserve the old buffer + // as every returning call will return new data anyway. + in.returnData = nil + + // Don't bother with the execution if there's no code. + if len(contract.Code) == 0 { + return nil, nil + } + + var ( + op OpCode // current opcode + mem = NewMemory() // bound memory + stack = newstack() // local stack + // For optimisation reason we're using uint64 as the program counter. + // It's theoretically possible to go above 2^64. The YP defines the PC + // to be uint256. Practically much less so feasible. + pc = uint64(0) // program counter + cost uint64 + // copies used by tracer + pcCopy uint64 // needed for the deferred Tracer + gasCopy uint64 // for Tracer to log gas remaining before execution + logged bool // deferred Tracer should ignore already logged steps + res []byte // result of the opcode execution function + ) + contract.Input = input + + // Reclaim the stack as an int pool when the execution stops + defer func() { in.intPool.put(stack.data...) }() + + if in.cfg.Debug { + defer func() { + if err != nil { + if !logged { + in.cfg.Tracer.CaptureState(in.evm, pcCopy, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err) + } else { + in.cfg.Tracer.CaptureFault(in.evm, pcCopy, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err) + } + } + }() + } + // The Interpreter main run loop (contextual). This loop runs until either an + // explicit STOP, RETURN or SELFDESTRUCT is executed, an error occurred during + // the execution of one of the operations or until the done flag is set by the + // parent context. + for atomic.LoadInt32(&in.evm.abort) == 0 { + if in.cfg.Debug { + // Capture pre-execution values for tracing. + logged, pcCopy, gasCopy = false, pc, contract.Gas + } + + // Get the operation from the jump table and validate the stack to ensure there are + // enough stack items available to perform the operation. + op = contract.GetOp(pc) + operation := in.cfg.JumpTable[op] + if !operation.valid { + return nil, fmt.Errorf("invalid opcode 0x%x", int(op)) + } + // Validate stack + if sLen := stack.len(); sLen < operation.minStack { + return nil, fmt.Errorf("stack underflow (%d <=> %d)", sLen, operation.minStack) + } else if sLen > operation.maxStack { + return nil, fmt.Errorf("stack limit reached %d (%d)", sLen, operation.maxStack) + } + // If the operation is valid, enforce and write restrictions + if in.readOnly && in.evm.chainRules.IsByzantium { + // If the interpreter is operating in readonly mode, make sure no + // state-modifying operation is performed. The 3rd stack item + // for a call operation is the value. Transferring value from one + // account to the others means the state is modified and should also + // return with an error. + if operation.writes || ((op == CALL || op == CALLEX) && stack.Back(2).Sign() != 0) { + return nil, errWriteProtection + } + } + // Static portion of gas + cost = operation.constantGas // For tracing + if !contract.UseGas(operation.constantGas) { + return nil, ErrOutOfGas + } + + var memorySize uint64 + // calculate the new memory size and expand the memory to fit + // the operation + // Memory check needs to be done prior to evaluating the dynamic gas portion, + // to detect calculation overflows + if operation.memorySize != nil { + memSize, overflow := operation.memorySize(stack) + if overflow { + return nil, errGasUintOverflow + } + // memory is expanded in words of 32 bytes. Gas + // is also calculated in words. + if memorySize, overflow = math.SafeMul(toWordSize(memSize), 32); overflow { + return nil, errGasUintOverflow + } + } + // Dynamic portion of gas + // consume the gas and return an error if not enough gas is available. + // cost is explicitly set so that the capture state defer method can get the proper cost + if operation.dynamicGas != nil { + var dynamicCost uint64 + dynamicCost, err = operation.dynamicGas(in.evm, contract, stack, mem, memorySize) + cost += dynamicCost // total cost, for debug tracing + if err != nil || !contract.UseGas(dynamicCost) { + return nil, ErrOutOfGas + } + } + if memorySize > 0 { + mem.Resize(memorySize) + } + + if in.cfg.Debug { + in.cfg.Tracer.CaptureState(in.evm, pc, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err) + logged = true + } + + // execute the operation + res, err = operation.execute(&pc, in, contract, mem, stack) + // verifyPool is a build flag. Pool verification makes sure the integrity + // of the integer pool by comparing values to a default value. + if verifyPool { + verifyIntegerPool(in.intPool) + } + // if the operation clears the return data (e.g. it has returning data) + // set the last return to the result of the operation. + if operation.returns { + in.returnData = res + } + + switch { + case err != nil: + return nil, err + case operation.reverts: + return res, errExecutionReverted + case operation.halts: + return res, nil + case !operation.jumps: + pc++ + } + } + return nil, nil +} + +// CanRun tells if the contract, passed as an argument, can be +// run by the current interpreter. +func (in *EVMInterpreter) CanRun(code []byte) bool { + return true +} |