mirror of
https://github.com/ethereum/go-ethereum.git
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77 lines
2.4 KiB
Go
77 lines
2.4 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Provides support for dealing with EVM assembly instructions (e.g., disassembling them).
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package asm
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import (
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"encoding/hex"
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"fmt"
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"github.com/ethereum/go-ethereum/core/vm"
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)
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// Apply function to each disassembled EVM instruction.
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func ForEachDisassembledInstruction(script []byte, fun func(uint64, vm.OpCode, []byte)) error {
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for pc := uint64(0); pc < uint64(len(script)); pc++ {
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op := vm.OpCode(script[pc])
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if op.IsPush() {
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a := uint64(op) - uint64(vm.PUSH1) + 1
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u := pc + 1 + a
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if uint64(len(script)) <= pc || uint64(len(script)) < u {
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return fmt.Errorf("incomplete push instruction at %v", pc)
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}
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fun(pc, op, script[pc+1:u])
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pc += a
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} else {
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fun(pc, op, make([]byte, 0))
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}
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}
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return nil
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}
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// Pretty-print all disassembled EVM instructions to stdout.
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func PrintDisassembled(code string) error {
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script, err := hex.DecodeString(code)
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if err != nil {
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return err
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}
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return ForEachDisassembledInstruction(script, func(pc uint64, op vm.OpCode, args []byte) {
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if args != nil && 0 < len(args) {
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fmt.Printf("%06v: %v 0x%x\n", pc, op, args)
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} else {
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fmt.Printf("%06v: %v\n", pc, op)
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}
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})
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}
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// Return all disassembled EVM instructions in human-readable format.
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func Disassemble(script []byte) ([]string, error) {
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instrs := make([]string, 0)
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err := ForEachDisassembledInstruction(script, func(pc uint64, op vm.OpCode, args []byte) {
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if args != nil && 0 < len(args) {
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instrs = append(instrs, fmt.Sprintf("%06v: %v 0x%x\n", pc, op, args))
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} else {
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instrs = append(instrs, fmt.Sprintf("%06v: %v\n", pc, op))
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}
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})
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if err != nil {
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return nil, err
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}
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return instrs, nil
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}
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