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#![allow(dead_code)]
use num_bigint::BigUint;
use std::collections::HashMap;
// Non-opcode gas prices
const GDEFAULT: usize = 1;
const GMEMORY: usize = 3;
const GQUADRATICMEMDENOM: usize = 512; // 1 gas per 512 quadwords
const GSTORAGEREFUND: usize = 15000;
const GSTORAGEKILL: usize = 5000;
const GSTORAGEMOD: usize = 5000;
const GSTORAGEADD: usize = 20000;
const GEXPONENTBYTE: usize = 10; // cost of EXP exponent per byte
const GCOPY: usize = 3; // cost to copy one 32 byte word
const GCONTRACTBYTE: usize = 200; // one byte of code in contract creation
const GCALLVALUETRANSFER: usize = 9000; // non-zero-valued call
const GLOGBYTE: usize = 8; // cost of a byte of logdata
const GTXCOST: usize = 21000; // TX BASE GAS COST
const GTXDATAZERO: usize = 4; // TX DATA ZERO BYTE GAS COST
const GTXDATANONZERO: usize = 68; // TX DATA NON ZERO BYTE GAS COST
const GSHA3WORD: usize = 6; // Cost of SHA3 per word
const GSHA256BASE: usize = 60; // Base c of SHA256
const GSHA256WORD: usize = 12; // Cost of SHA256 per word
const GRIPEMD160BASE: usize = 600; // Base cost of RIPEMD160
const GRIPEMD160WORD: usize = 120; // Cost of RIPEMD160 per word
const GIDENTITYBASE: usize = 15; // Base cost of indentity
const GIDENTITYWORD: usize = 3; // Cost of identity per word
const GECRECOVER: usize = 3000; // Cost of ecrecover op
const GSTIPEND: usize = 2300;
const GCALLNEWACCOUNT: usize = 25000;
const GSUICIDEREFUND: usize = 24000;
pub struct Stack {
pc: usize,
calldata_i: usize,
stack: Vec<[u8; 32]>,
mem: Vec<u8>,
gas: u64,
opcodes: HashMap<u8, Opcode>,
}
impl Stack {
pub fn new() -> Stack {
let mut s = Stack {
pc: 0,
calldata_i: 0,
stack: Vec::new(),
mem: Vec::new(),
gas: 10000000000,
opcodes: HashMap::new(),
};
s.opcodes = new_opcodes();
s
}
fn print_stack(&self) {
for i in (0..self.stack.len()).rev() {
println!("{:x?}", &self.stack[i][28..]);
}
}
fn push(&mut self, b: [u8; 32]) {
self.stack.push(b);
}
// push_arbitrary performs a push, but first converting the arbitrary-length input into a 32
// byte array
fn push_arbitrary(&mut self, b: &[u8]) {
// TODO if b.len()>32 return error
let mut d: [u8; 32] = [0; 32];
d[32 - b.len()..].copy_from_slice(&b[..]);
self.stack.push(d);
}
// put_arbitrary puts in the last element of the stack the value
fn put_arbitrary(&mut self, b: &[u8]) {
// TODO if b.len()>32 return error
let mut d: [u8; 32] = [0; 32];
d[32 - b.len()..].copy_from_slice(&b[..]);
let l = self.stack.len();
self.stack[l - 1] = d;
}
fn pop(&mut self) -> [u8; 32] {
match self.stack.pop() {
Some(x) => return x,
None => panic!("err"),
}
}
fn execute(&mut self, code: &[u8], calldata: &[u8], debug: bool) -> Vec<u8> {
self.pc = 0;
self.calldata_i = 0;
let l = code.len();
while self.pc < l {
let opcode = code[self.pc];
if !self.opcodes.contains_key(&opcode) {
panic!("invalid opcode {:x}", opcode);
}
if debug {
println!(
"{:?} (0x{:x}): pc={:?} gas={:?}\nstack:",
self.opcodes.get(&opcode).unwrap().name,
opcode,
self.pc,
self.gas,
);
self.print_stack();
println!("");
}
match opcode & 0xf0 {
0x00 => {
// arithmetic
match opcode {
0x00 => {
return Vec::new();
}
0x01 => self.add(),
0x02 => self.mul(),
0x03 => self.sub(),
0x04 => self.div(),
0x05 => self.sdiv(),
0x06 => self.modulus(),
0x07 => self.smod(),
0x08 => self.add_mod(),
0x09 => self.mul_mod(),
0x0a => self.exp(),
// 0x0b => self.sign_extend(),
_ => panic!("unimplemented {:x}", opcode),
}
self.pc += 1;
}
0x30 => {
match opcode {
0x35 => {
self.calldata_load(&calldata);
}
_ => panic!("unimplemented {:x}", opcode),
}
self.pc += 1;
}
0x50 => {
self.pc += 1;
match opcode {
0x52 => self.mstore(),
_ => panic!("unimplemented {:x}", opcode),
}
}
0x60 | 0x70 => {
// push
let n = (opcode - 0x5f) as usize;
self.push_arbitrary(&code[self.pc + 1..self.pc + 1 + n]);
self.pc += 1 + n;
}
0xf0 => {
if opcode == 0xf3 {
let pos_to_return = u256_to_u64(self.pop()) as usize;
let len_to_return = u256_to_u64(self.pop()) as usize;
return self.mem[pos_to_return..pos_to_return + len_to_return].to_vec();
}
}
_ => {
panic!("unimplemented {:x}", opcode);
}
}
self.gas -= self.opcodes.get(&opcode).unwrap().gas;
}
return Vec::new();
}
// arithmetic
// TODO instead of [u8;32] converted to BigUint, use custom type uint256 that implements all
// the arithmetic
fn add(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
self.push_arbitrary(&(b0 + b1).to_bytes_be());
}
fn mul(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
self.push_arbitrary(&(b0 * b1).to_bytes_be());
}
fn sub(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
if b0 >= b1 {
self.push_arbitrary(&(b0 - b1).to_bytes_be());
} else {
// 2**256
let max =
"115792089237316195423570985008687907853269984665640564039457584007913129639936"
.parse::<BigUint>()
.unwrap();
self.push_arbitrary(&(max + b0 - b1).to_bytes_be());
}
}
fn div(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
self.push_arbitrary(&(b0 / b1).to_bytes_be());
}
fn sdiv(&mut self) {
panic!("unimplemented");
}
fn modulus(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
self.push_arbitrary(&(b0 % b1).to_bytes_be());
}
fn smod(&mut self) {
panic!("unimplemented");
}
fn add_mod(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
let b2 = BigUint::from_bytes_be(&self.pop()[..]);
self.push_arbitrary(&(b0 + b1 % b2).to_bytes_be());
}
fn mul_mod(&mut self) {
let b0 = BigUint::from_bytes_be(&self.pop()[..]);
let b1 = BigUint::from_bytes_be(&self.pop()[..]);
let b2 = BigUint::from_bytes_be(&self.pop()[..]);
self.push_arbitrary(&(b0 * b1 % b2).to_bytes_be());
}
fn exp(&mut self) {
panic!("unimplemented");
// let b0 = BigUint::from_bytes_be(&self.pop()[..]);
// let b1 = BigUint::from_bytes_be(&self.pop()[..]);
// self.push_arbitrary(&(pow(b0, b1)).to_bytes_be());
}
// boolean
// crypto
// contract context
fn calldata_load(&mut self, calldata: &[u8]) {
self.put_arbitrary(&calldata[self.calldata_i..self.calldata_i + 32]);
self.calldata_i += 32;
}
// blockchain context
// storage and execution
fn extend_mem(&mut self, start: usize, size: usize) {
if size <= self.mem.len() || start + size <= self.mem.len() {
return;
}
let old_size = self.mem.len() / 32;
let new_size = (start + size) / 32;
let old_total_fee = old_size * GMEMORY + old_size.pow(2) / GQUADRATICMEMDENOM;
let new_total_fee = new_size * GMEMORY + new_size.pow(2) / GQUADRATICMEMDENOM;
let mem_fee = new_total_fee - old_total_fee;
self.gas -= mem_fee as u64;
let mut new_bytes: Vec<u8> = vec![0; size];
self.mem.append(&mut new_bytes);
}
fn mstore(&mut self) {
let pos = u256_to_u64(self.pop());
let val = self.pop();
self.extend_mem(pos as usize, 32);
self.mem[pos as usize..].copy_from_slice(&val);
}
}
fn u256_to_u64(a: [u8; 32]) -> u64 {
let mut b8: [u8; 8] = [0; 8];
b8.copy_from_slice(&a[32 - 8..32]);
let pos = u64::from_be_bytes(b8);
pos
}
fn str_to_u256(s: &str) -> [u8; 32] {
let bi = s.parse::<BigUint>().unwrap().to_bytes_be();
let mut r: [u8; 32] = [0; 32];
r[32 - bi.len()..].copy_from_slice(&bi[..]);
r
}
struct Opcode {
name: String,
ins: u32,
outs: u32,
gas: u64,
}
fn new_opcode(name: &str, ins: u32, outs: u32, gas: u64) -> Opcode {
Opcode {
name: name.to_string(),
ins,
outs,
gas,
}
}
fn new_opcodes() -> HashMap<u8, Opcode> {
let mut opcodes: HashMap<u8, Opcode> = HashMap::new();
// arithmetic
opcodes.insert(0x00, new_opcode("STOP", 0, 0, 0));
opcodes.insert(0x01, new_opcode("ADD", 2, 1, 3));
opcodes.insert(0x02, new_opcode("MUL", 2, 1, 5));
opcodes.insert(0x03, new_opcode("SUB", 2, 1, 3));
opcodes.insert(0x04, new_opcode("DIV", 2, 1, 5));
opcodes.insert(0x05, new_opcode("SDIV", 2, 1, 5));
opcodes.insert(0x06, new_opcode("MOD", 2, 1, 5));
opcodes.insert(0x07, new_opcode("SMOD", 2, 1, 5));
opcodes.insert(0x08, new_opcode("ADDMOD", 3, 1, 8));
opcodes.insert(0x09, new_opcode("MULMOD", 3, 1, 8));
opcodes.insert(0x0a, new_opcode("EXP", 2, 1, 10));
opcodes.insert(0x0b, new_opcode("SIGNEXTEND", 2, 1, 5));
// boolean
opcodes.insert(0x10, new_opcode("LT", 2, 1, 3));
opcodes.insert(0x11, new_opcode("GT", 2, 1, 3));
opcodes.insert(0x12, new_opcode("SLT", 2, 1, 3));
opcodes.insert(0x13, new_opcode("SGT", 2, 1, 3));
opcodes.insert(0x14, new_opcode("EQ", 2, 1, 3));
opcodes.insert(0x15, new_opcode("ISZERO", 1, 1, 3));
opcodes.insert(0x16, new_opcode("AND", 2, 1, 3));
opcodes.insert(0x17, new_opcode("OR", 2, 1, 3));
opcodes.insert(0x18, new_opcode("XOR", 2, 1, 3));
opcodes.insert(0x19, new_opcode("NOT", 1, 1, 3));
opcodes.insert(0x1a, new_opcode("BYTE", 2, 1, 3));
// crypto
opcodes.insert(0x20, new_opcode("SHA3", 2, 1, 30));
// contract context
opcodes.insert(0x30, new_opcode("ADDRESS", 0, 1, 2));
opcodes.insert(0x31, new_opcode("BALANCE", 1, 1, 20));
opcodes.insert(0x32, new_opcode("ORIGIN", 0, 1, 2));
opcodes.insert(0x33, new_opcode("CALLER", 0, 1, 2));
opcodes.insert(0x34, new_opcode("CALLVALUE", 0, 1, 2));
opcodes.insert(0x35, new_opcode("CALLDATALOAD", 1, 1, 3));
opcodes.insert(0x36, new_opcode("CALLDATASIZE", 0, 1, 2));
opcodes.insert(0x37, new_opcode("CALLDATACOPY", 3, 0, 3));
opcodes.insert(0x38, new_opcode("CODESIZE", 0, 1, 2));
opcodes.insert(0x39, new_opcode("CODECOPY", 3, 0, 3));
opcodes.insert(0x3a, new_opcode("GASPRICE", 0, 1, 2));
opcodes.insert(0x3b, new_opcode("EXTCODESIZE", 1, 1, 20));
opcodes.insert(0x3c, new_opcode("EXTCODECOPY", 4, 0, 20));
// blockchain context
opcodes.insert(0x40, new_opcode("BLOCKHASH", 1, 1, 20));
opcodes.insert(0x41, new_opcode("COINBASE", 0, 1, 2));
opcodes.insert(0x42, new_opcode("TIMESTAMP", 0, 1, 2));
opcodes.insert(0x43, new_opcode("NUMBER", 0, 1, 2));
opcodes.insert(0x44, new_opcode("DIFFICULTY", 0, 1, 2));
opcodes.insert(0x45, new_opcode("GASLIMIT", 0, 1, 2));
// storage and execution
opcodes.insert(0x50, new_opcode("POP", 1, 0, 2));
opcodes.insert(0x51, new_opcode("MLOAD", 1, 1, 3));
opcodes.insert(0x52, new_opcode("MSTORE", 2, 0, 3));
opcodes.insert(0x53, new_opcode("MSTORE8", 2, 0, 3));
opcodes.insert(0x54, new_opcode("SLOAD", 1, 1, 50));
opcodes.insert(0x55, new_opcode("SSTORE", 2, 0, 0));
opcodes.insert(0x56, new_opcode("JUMP", 1, 0, 8));
opcodes.insert(0x57, new_opcode("JUMPI", 2, 0, 10));
opcodes.insert(0x58, new_opcode("PC", 0, 1, 2));
opcodes.insert(0x59, new_opcode("MSIZE", 0, 1, 2));
opcodes.insert(0x5a, new_opcode("GAS", 0, 1, 2));
opcodes.insert(0x5b, new_opcode("JUMPDEST", 0, 0, 1));
// logging
opcodes.insert(0xa0, new_opcode("LOG0", 2, 0, 375));
opcodes.insert(0xa1, new_opcode("LOG1", 3, 0, 750));
opcodes.insert(0xa2, new_opcode("LOG2", 4, 0, 1125));
opcodes.insert(0xa3, new_opcode("LOG3", 5, 0, 1500));
opcodes.insert(0xa4, new_opcode("LOG4", 6, 0, 1875));
// closures
opcodes.insert(0xf0, new_opcode("CREATE", 3, 1, 32000));
opcodes.insert(0xf1, new_opcode("CALL", 7, 1, 40));
opcodes.insert(0xf2, new_opcode("CALLCODE", 7, 1, 40));
opcodes.insert(0xf3, new_opcode("RETURN", 2, 0, 0));
opcodes.insert(0xf4, new_opcode("DELEGATECALL", 6, 0, 40));
opcodes.insert(0xff, new_opcode("SUICIDE", 1, 0, 0));
for i in 1..33 {
let name = format!("PUSH{}", i);
opcodes.insert(0x5f + i, new_opcode(&name, 0, 1, 3));
}
for i in 1..17 {
let name = format!("DUP{}", i);
opcodes.insert(0x7f + i, new_opcode(&name, i as u32, i as u32 + 1, 3));
let name = format!("SWAP{}", i);
opcodes.insert(0x8f + i, new_opcode(&name, i as u32 + 1, i as u32 + 1, 3));
}
opcodes
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn stack_simple_push_pop() {
let mut s = Stack::new();
s.push(str_to_u256("1"));
s.push(str_to_u256("2"));
s.push(str_to_u256("3"));
assert_eq!(s.pop(), str_to_u256("3"));
assert_eq!(s.pop(), str_to_u256("2"));
assert_eq!(s.pop(), str_to_u256("1"));
// assert_eq!(s.pop(), str_to_u256("1"));
// assert_eq!(s.pop(), error); // TODO expect error as stack is empty
}
// arithmetic
#[test]
fn execute_opcodes_0() {
let code = hex::decode("6005600c01").unwrap(); // 5+12
let calldata = vec![];
let mut s = Stack::new();
s.execute(&code, &calldata, false);
assert_eq!(s.pop(), str_to_u256("17"));
assert_eq!(s.gas, 9999999991);
assert_eq!(s.pc, 5);
}
#[test]
fn execute_opcodes_1() {
let code = hex::decode("60056004016000526001601ff3").unwrap();
let calldata = vec![];
let mut s = Stack::new();
let out = s.execute(&code, &calldata, false);
assert_eq!(out[0], 0x09);
assert_eq!(s.gas, 9999999976);
assert_eq!(s.pc, 12);
// assert_eq!(s.pop(), err); // TODO expect error as stack is empty
}
#[test]
fn execute_opcodes_2() {
let code = hex::decode("61010161010201").unwrap();
let calldata = vec![];
let mut s = Stack::new();
s.execute(&code, &calldata, false);
// assert_eq!(out[0], 0x09);
assert_eq!(s.gas, 9999999991);
assert_eq!(s.pc, 7);
assert_eq!(s.pop(), str_to_u256("515"));
}
#[test]
fn execute_opcodes_3() {
// contains calldata
let code = hex::decode("60003560203501").unwrap();
let calldata = hex::decode("00000000000000000000000000000000000000000000000000000000000000050000000000000000000000000000000000000000000000000000000000000004").unwrap();
let mut s = Stack::new();
s.execute(&code, &calldata, false);
assert_eq!(s.gas, 9999999985);
assert_eq!(s.pc, 7);
assert_eq!(s.pop(), str_to_u256("9"));
}
}
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