neo-go/pkg/vm/vm.go
2022-11-16 00:40:12 +03:00

1980 lines
50 KiB
Go

package vm
import (
"crypto/elliptic"
"encoding/binary"
"encoding/json"
"errors"
"fmt"
"io"
"math"
"math/big"
"os"
"text/tabwriter"
"unicode/utf8"
"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/nef"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/util/slice"
"github.com/nspcc-dev/neo-go/pkg/vm/invocations"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
"github.com/nspcc-dev/neo-go/pkg/vm/vmstate"
)
type errorAtInstruct struct {
ip int
op opcode.Opcode
err interface{}
}
func (e *errorAtInstruct) Error() string {
return fmt.Sprintf("at instruction %d (%s): %s", e.ip, e.op, e.err)
}
func newError(ip int, op opcode.Opcode, err interface{}) *errorAtInstruct {
return &errorAtInstruct{ip: ip, op: op, err: err}
}
// StateMessage is a vm state message which could be used as an additional info, for example by cli.
type StateMessage string
const (
// MaxInvocationStackSize is the maximum size of an invocation stack.
MaxInvocationStackSize = 1024
// MaxTryNestingDepth is the maximum level of TRY nesting allowed,
// that is you can't have more exception handling contexts than this.
MaxTryNestingDepth = 16
// MaxStackSize is the maximum number of items allowed to be
// on all stacks at once.
MaxStackSize = 2 * 1024
maxSHLArg = stackitem.MaxBigIntegerSizeBits
)
// SyscallHandler is a type for syscall handler.
type SyscallHandler = func(*VM, uint32) error
// VM represents the virtual machine.
type VM struct {
state vmstate.State
// callback to get interop price
getPrice func(opcode.Opcode, []byte) int64
istack Stack // invocation stack.
estack *Stack // execution stack.
uncaughtException stackitem.Item // exception being handled
refs refCounter
gasConsumed int64
GasLimit int64
// SyscallHandler handles SYSCALL opcode.
SyscallHandler func(v *VM, id uint32) error
// LoadToken handles CALLT opcode.
LoadToken func(id int32) error
trigger trigger.Type
// invTree is a top-level invocation tree (if enabled).
invTree *invocations.Tree
}
var (
bigMinusOne = big.NewInt(-1)
bigZero = big.NewInt(0)
bigOne = big.NewInt(1)
bigTwo = big.NewInt(2)
)
// New returns a new VM object ready to load AVM bytecode scripts.
func New() *VM {
return NewWithTrigger(trigger.Application)
}
// NewWithTrigger returns a new VM for executions triggered by t.
func NewWithTrigger(t trigger.Type) *VM {
vm := &VM{
state: vmstate.None,
trigger: t,
}
initStack(&vm.istack, "invocation", nil)
vm.istack.elems = make([]Element, 0, 8) // Most of invocations use one-two contracts, but they're likely to have internal calls.
vm.estack = newStack("evaluation", &vm.refs)
return vm
}
// SetPriceGetter registers the given PriceGetterFunc in v.
// f accepts vm's Context, current instruction and instruction parameter.
func (v *VM) SetPriceGetter(f func(opcode.Opcode, []byte) int64) {
v.getPrice = f
}
// Reset allows to reuse existing VM for subsequent executions making them somewhat
// more efficient. It reuses invocation and evaluation stacks as well as VM structure
// itself.
func (v *VM) Reset(t trigger.Type) {
v.state = vmstate.None
v.getPrice = nil
v.istack.elems = v.istack.elems[:0]
v.estack.elems = v.estack.elems[:0]
v.uncaughtException = nil
v.refs = 0
v.gasConsumed = 0
v.GasLimit = 0
v.SyscallHandler = nil
v.LoadToken = nil
v.trigger = t
v.invTree = nil
}
// GasConsumed returns the amount of GAS consumed during execution.
func (v *VM) GasConsumed() int64 {
return v.gasConsumed
}
// AddGas consumes the specified amount of gas. It returns true if gas limit wasn't exceeded.
func (v *VM) AddGas(gas int64) bool {
v.gasConsumed += gas
return v.GasLimit < 0 || v.gasConsumed <= v.GasLimit
}
// Estack returns the evaluation stack, so interop hooks can utilize this.
func (v *VM) Estack() *Stack {
return v.estack
}
// Istack returns the invocation stack, so interop hooks can utilize this.
func (v *VM) Istack() *Stack {
return &v.istack
}
// PrintOps prints the opcodes of the current loaded program to stdout.
func (v *VM) PrintOps(out io.Writer) {
if out == nil {
out = os.Stdout
}
w := tabwriter.NewWriter(out, 0, 0, 4, ' ', 0)
fmt.Fprintln(w, "INDEX\tOPCODE\tPARAMETER")
realctx := v.Context()
ctx := &Context{sc: realctx.sc}
for {
cursor := ""
instr, parameter, err := ctx.Next()
if ctx.ip == realctx.ip {
cursor = "\t<<"
}
if err != nil {
fmt.Fprintf(w, "%d\t%s\tERROR: %s%s\n", ctx.ip, instr, err, cursor)
break
}
var desc = ""
if parameter != nil {
switch instr {
case opcode.JMP, opcode.JMPIF, opcode.JMPIFNOT, opcode.CALL,
opcode.JMPEQ, opcode.JMPNE,
opcode.JMPGT, opcode.JMPGE, opcode.JMPLE, opcode.JMPLT,
opcode.JMPL, opcode.JMPIFL, opcode.JMPIFNOTL, opcode.CALLL,
opcode.JMPEQL, opcode.JMPNEL,
opcode.JMPGTL, opcode.JMPGEL, opcode.JMPLEL, opcode.JMPLTL,
opcode.PUSHA, opcode.ENDTRY, opcode.ENDTRYL:
desc = getOffsetDesc(ctx, parameter)
case opcode.TRY, opcode.TRYL:
catchP, finallyP := getTryParams(instr, parameter)
desc = fmt.Sprintf("catch %s, finally %s",
getOffsetDesc(ctx, catchP), getOffsetDesc(ctx, finallyP))
case opcode.INITSSLOT:
desc = fmt.Sprint(parameter[0])
case opcode.CONVERT, opcode.ISTYPE:
typ := stackitem.Type(parameter[0])
desc = fmt.Sprintf("%s (%x)", typ, parameter[0])
case opcode.INITSLOT:
desc = fmt.Sprintf("%d local, %d arg", parameter[0], parameter[1])
case opcode.SYSCALL:
name, err := interopnames.FromID(GetInteropID(parameter))
if err != nil {
name = "not found"
}
desc = fmt.Sprintf("%s (%x)", name, parameter)
case opcode.PUSHINT8, opcode.PUSHINT16, opcode.PUSHINT32,
opcode.PUSHINT64, opcode.PUSHINT128, opcode.PUSHINT256:
val := bigint.FromBytes(parameter)
desc = fmt.Sprintf("%d (%x)", val, parameter)
case opcode.LDLOC, opcode.STLOC, opcode.LDARG, opcode.STARG, opcode.LDSFLD, opcode.STSFLD:
desc = fmt.Sprintf("%d (%x)", parameter[0], parameter)
default:
if utf8.Valid(parameter) {
desc = fmt.Sprintf("%x (%q)", parameter, parameter)
} else {
desc = fmt.Sprintf("%x", parameter)
}
}
}
fmt.Fprintf(w, "%d\t%s\t%s%s\n", ctx.ip, instr, desc, cursor)
if ctx.nextip >= len(ctx.sc.prog) {
break
}
}
w.Flush()
}
func getOffsetDesc(ctx *Context, parameter []byte) string {
offset, rOffset, err := calcJumpOffset(ctx, parameter)
if err != nil {
return fmt.Sprintf("ERROR: %v", err)
}
return fmt.Sprintf("%d (%d/%x)", offset, rOffset, parameter)
}
// AddBreakPoint adds a breakpoint to the current context.
func (v *VM) AddBreakPoint(n int) {
ctx := v.Context()
ctx.sc.breakPoints = append(ctx.sc.breakPoints, n)
}
// AddBreakPointRel adds a breakpoint relative to the current
// instruction pointer.
func (v *VM) AddBreakPointRel(n int) {
ctx := v.Context()
v.AddBreakPoint(ctx.nextip + n)
}
// LoadFileWithFlags loads a program in NEF format from the given path, ready to execute it.
func (v *VM) LoadFileWithFlags(path string, f callflag.CallFlag) error {
b, err := os.ReadFile(path)
if err != nil {
return err
}
nef, err := nef.FileFromBytes(b)
if err != nil {
return err
}
v.LoadWithFlags(nef.Script, f)
return nil
}
// CollectInvocationTree enables collecting invocation tree data.
func (v *VM) EnableInvocationTree() {
v.invTree = &invocations.Tree{}
}
// GetInvocationTree returns the current invocation tree structure.
func (v *VM) GetInvocationTree() *invocations.Tree {
return v.invTree
}
// Load initializes the VM with the program given.
func (v *VM) Load(prog []byte) {
v.LoadWithFlags(prog, callflag.NoneFlag)
}
// LoadWithFlags initializes the VM with the program and flags given.
func (v *VM) LoadWithFlags(prog []byte, f callflag.CallFlag) {
// Clear all stacks and state, it could be a reload.
v.istack.Clear()
v.estack.Clear()
v.state = vmstate.None
v.gasConsumed = 0
v.invTree = nil
v.LoadScriptWithFlags(prog, f)
}
// LoadScript loads a script from the internal script table. It
// will immediately push a new context created from this script to
// the invocation stack and starts executing it.
func (v *VM) LoadScript(b []byte) {
v.LoadScriptWithFlags(b, callflag.NoneFlag)
}
// LoadScriptWithFlags loads script and sets call flag to f.
func (v *VM) LoadScriptWithFlags(b []byte, f callflag.CallFlag) {
v.loadScriptWithCallingHash(b, nil, v.GetCurrentScriptHash(), util.Uint160{}, f, -1, 0, nil)
}
// LoadScriptWithHash is similar to the LoadScriptWithFlags method, but it also loads
// the given script hash directly into the Context to avoid its recalculations and to make
// it possible to override it for deployed contracts with special hashes (the function
// assumes that it is used for deployed contracts setting context's parameters
// accordingly). It's up to the user of this function to make sure the script and hash match
// each other.
func (v *VM) LoadScriptWithHash(b []byte, hash util.Uint160, f callflag.CallFlag) {
v.loadScriptWithCallingHash(b, nil, v.GetCurrentScriptHash(), hash, f, 1, 0, nil)
}
// LoadNEFMethod allows to create a context to execute a method from the NEF
// file with the specified caller and executing hash, call flags, return value,
// method and _initialize offsets.
func (v *VM) LoadNEFMethod(exe *nef.File, caller util.Uint160, hash util.Uint160, f callflag.CallFlag,
hasReturn bool, methodOff int, initOff int, onContextUnload ContextUnloadCallback) {
var rvcount int
if hasReturn {
rvcount = 1
}
v.loadScriptWithCallingHash(exe.Script, exe, caller, hash, f, rvcount, methodOff, onContextUnload)
if initOff >= 0 {
v.Call(initOff)
}
}
// loadScriptWithCallingHash is similar to LoadScriptWithHash but sets calling hash explicitly.
// It should be used for calling from native contracts.
func (v *VM) loadScriptWithCallingHash(b []byte, exe *nef.File, caller util.Uint160,
hash util.Uint160, f callflag.CallFlag, rvcount int, offset int, onContextUnload ContextUnloadCallback) {
v.checkInvocationStackSize()
ctx := NewContextWithParams(b, rvcount, offset)
parent := v.Context()
if parent != nil {
ctx.sc.callingContext = parent.sc
parent.sc.estack = v.estack
}
if rvcount != -1 || v.estack.Len() != 0 {
v.estack = subStack(v.estack)
}
ctx.sc.estack = v.estack
initStack(&ctx.tryStack, "exception", nil)
ctx.sc.callFlag = f
ctx.sc.scriptHash = hash
ctx.sc.callingScriptHash = caller
ctx.sc.NEF = exe
if v.invTree != nil {
curTree := v.invTree
if parent != nil {
curTree = parent.sc.invTree
}
newTree := &invocations.Tree{Current: ctx.ScriptHash()}
curTree.Calls = append(curTree.Calls, newTree)
ctx.sc.invTree = newTree
}
ctx.sc.onUnload = onContextUnload
v.istack.PushItem(ctx)
}
// Context returns the current executed context. Nil if there is no context,
// which implies no program is loaded.
func (v *VM) Context() *Context {
if v.istack.Len() == 0 {
return nil
}
return v.istack.Peek(0).value.(*Context)
}
// PopResult is used to pop the first item of the evaluation stack. This allows
// us to test the compiler and the vm in a bi-directional way.
func (v *VM) PopResult() interface{} {
if v.estack.Len() == 0 {
return nil
}
return v.estack.Pop().Value()
}
// DumpIStack returns json formatted representation of the invocation stack.
func (v *VM) DumpIStack() string {
b, _ := json.MarshalIndent(v.istack.ToArray(), "", " ")
return string(b)
}
// DumpEStack returns json formatted representation of the execution stack.
func (v *VM) DumpEStack() string {
return dumpStack(v.estack)
}
// dumpStack returns json formatted representation of the given stack.
func dumpStack(s *Stack) string {
b, _ := json.MarshalIndent(s, "", " ")
return string(b)
}
// State returns the state for the VM.
func (v *VM) State() vmstate.State {
return v.state
}
// Ready returns true if the VM is ready to execute the loaded program.
// It will return false if no program is loaded.
func (v *VM) Ready() bool {
return v.istack.Len() > 0
}
// Run starts execution of the loaded program.
func (v *VM) Run() error {
var ctx *Context
if !v.Ready() {
v.state = vmstate.Fault
return errors.New("no program loaded")
}
if v.state.HasFlag(vmstate.Fault) {
// VM already ran something and failed, in general its state is
// undefined in this case so we can't run anything.
return errors.New("VM has failed")
}
// vmstate.Halt (the default) or vmstate.Break are safe to continue.
v.state = vmstate.None
ctx = v.Context()
for {
switch {
case v.state.HasFlag(vmstate.Fault):
// Should be caught and reported already by the v.Step(),
// but we're checking here anyway just in case.
return errors.New("VM has failed")
case v.state.HasFlag(vmstate.Halt), v.state.HasFlag(vmstate.Break):
// Normal exit from this loop.
return nil
case v.state == vmstate.None:
if err := v.step(ctx); err != nil {
return err
}
default:
v.state = vmstate.Fault
return errors.New("unknown state")
}
// check for breakpoint before executing the next instruction
ctx = v.Context()
if ctx != nil && ctx.atBreakPoint() {
v.state = vmstate.Break
}
}
}
// Step 1 instruction in the program.
func (v *VM) Step() error {
ctx := v.Context()
return v.step(ctx)
}
// step executes one instruction in the given context.
func (v *VM) step(ctx *Context) error {
op, param, err := ctx.Next()
if err != nil {
v.state = vmstate.Fault
return newError(ctx.ip, op, err)
}
return v.execute(ctx, op, param)
}
// StepInto behaves the same as “step over” in case the line does not contain a function. Otherwise,
// the debugger will enter the called function and continue line-by-line debugging there.
func (v *VM) StepInto() error {
ctx := v.Context()
if ctx == nil {
v.state = vmstate.Halt
}
if v.HasStopped() {
return nil
}
if ctx != nil && ctx.sc.prog != nil {
op, param, err := ctx.Next()
if err != nil {
v.state = vmstate.Fault
return newError(ctx.ip, op, err)
}
vErr := v.execute(ctx, op, param)
if vErr != nil {
return vErr
}
}
cctx := v.Context()
if cctx != nil && cctx.atBreakPoint() {
v.state = vmstate.Break
}
return nil
}
// StepOut takes the debugger to the line where the current function was called.
func (v *VM) StepOut() error {
var err error
if v.state == vmstate.Break {
v.state = vmstate.None
}
expSize := v.istack.Len()
for v.state == vmstate.None && v.istack.Len() >= expSize {
err = v.StepInto()
}
if v.state == vmstate.None {
v.state = vmstate.Break
}
return err
}
// StepOver takes the debugger to the line that will step over the given line.
// If the line contains a function, the function will be executed and the result is returned without debugging each line.
func (v *VM) StepOver() error {
var err error
if v.HasStopped() {
return err
}
if v.state == vmstate.Break {
v.state = vmstate.None
}
expSize := v.istack.Len()
for {
err = v.StepInto()
if !(v.state == vmstate.None && v.istack.Len() > expSize) {
break
}
}
if v.state == vmstate.None {
v.state = vmstate.Break
}
return err
}
// HasFailed returns whether the VM is in the failed state now. Usually, it's used to
// check status after Run.
func (v *VM) HasFailed() bool {
return v.state.HasFlag(vmstate.Fault)
}
// HasStopped returns whether the VM is in the Halt or Failed state.
func (v *VM) HasStopped() bool {
return v.state.HasFlag(vmstate.Halt) || v.state.HasFlag(vmstate.Fault)
}
// HasHalted returns whether the VM is in the Halt state.
func (v *VM) HasHalted() bool {
return v.state.HasFlag(vmstate.Halt)
}
// AtBreakpoint returns whether the VM is at breakpoint.
func (v *VM) AtBreakpoint() bool {
return v.state.HasFlag(vmstate.Break)
}
// GetInteropID converts instruction parameter to an interop ID.
func GetInteropID(parameter []byte) uint32 {
return binary.LittleEndian.Uint32(parameter)
}
// execute performs an instruction cycle in the VM. Acting on the instruction (opcode).
func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err error) {
// Instead of polluting the whole VM logic with error handling, we will recover
// each panic at a central point, putting the VM in a fault state and setting error.
defer func() {
if errRecover := recover(); errRecover != nil {
v.state = vmstate.Fault
err = newError(ctx.ip, op, errRecover)
} else if v.refs > MaxStackSize {
v.state = vmstate.Fault
err = newError(ctx.ip, op, "stack is too big")
}
}()
if v.getPrice != nil && ctx.ip < len(ctx.sc.prog) {
v.gasConsumed += v.getPrice(op, parameter)
if v.GasLimit >= 0 && v.gasConsumed > v.GasLimit {
panic("gas limit is exceeded")
}
}
if op <= opcode.PUSHINT256 {
v.estack.PushItem(stackitem.NewBigInteger(bigint.FromBytes(parameter)))
return
}
switch op {
case opcode.PUSHM1, opcode.PUSH0, opcode.PUSH1, opcode.PUSH2, opcode.PUSH3,
opcode.PUSH4, opcode.PUSH5, opcode.PUSH6, opcode.PUSH7,
opcode.PUSH8, opcode.PUSH9, opcode.PUSH10, opcode.PUSH11,
opcode.PUSH12, opcode.PUSH13, opcode.PUSH14, opcode.PUSH15,
opcode.PUSH16:
val := int(op) - int(opcode.PUSH0)
v.estack.PushItem(stackitem.NewBigInteger(big.NewInt(int64(val))))
case opcode.PUSHDATA1, opcode.PUSHDATA2, opcode.PUSHDATA4:
v.estack.PushItem(stackitem.NewByteArray(parameter))
case opcode.PUSHA:
n := getJumpOffset(ctx, parameter)
ptr := stackitem.NewPointerWithHash(n, ctx.sc.prog, ctx.ScriptHash())
v.estack.PushItem(ptr)
case opcode.PUSHNULL:
v.estack.PushItem(stackitem.Null{})
case opcode.ISNULL:
_, ok := v.estack.Pop().value.(stackitem.Null)
v.estack.PushItem(stackitem.Bool(ok))
case opcode.ISTYPE:
res := v.estack.Pop().Item()
v.estack.PushItem(stackitem.Bool(res.Type() == stackitem.Type(parameter[0])))
case opcode.CONVERT:
typ := stackitem.Type(parameter[0])
item := v.estack.Pop().Item()
result, err := item.Convert(typ)
if err != nil {
panic(err)
}
v.estack.PushItem(result)
case opcode.INITSSLOT:
if parameter[0] == 0 {
panic("zero argument")
}
ctx.sc.static.init(int(parameter[0]), &v.refs)
case opcode.INITSLOT:
if ctx.local != nil || ctx.arguments != nil {
panic("already initialized")
}
if parameter[0] == 0 && parameter[1] == 0 {
panic("zero argument")
}
if parameter[0] > 0 {
ctx.local.init(int(parameter[0]), &v.refs)
}
if parameter[1] > 0 {
sz := int(parameter[1])
ctx.arguments.init(sz, &v.refs)
for i := 0; i < sz; i++ {
ctx.arguments.Set(i, v.estack.Pop().Item(), &v.refs)
}
}
case opcode.LDSFLD0, opcode.LDSFLD1, opcode.LDSFLD2, opcode.LDSFLD3, opcode.LDSFLD4, opcode.LDSFLD5, opcode.LDSFLD6:
item := ctx.sc.static.Get(int(op - opcode.LDSFLD0))
v.estack.PushItem(item)
case opcode.LDSFLD:
item := ctx.sc.static.Get(int(parameter[0]))
v.estack.PushItem(item)
case opcode.STSFLD0, opcode.STSFLD1, opcode.STSFLD2, opcode.STSFLD3, opcode.STSFLD4, opcode.STSFLD5, opcode.STSFLD6:
item := v.estack.Pop().Item()
ctx.sc.static.Set(int(op-opcode.STSFLD0), item, &v.refs)
case opcode.STSFLD:
item := v.estack.Pop().Item()
ctx.sc.static.Set(int(parameter[0]), item, &v.refs)
case opcode.LDLOC0, opcode.LDLOC1, opcode.LDLOC2, opcode.LDLOC3, opcode.LDLOC4, opcode.LDLOC5, opcode.LDLOC6:
item := ctx.local.Get(int(op - opcode.LDLOC0))
v.estack.PushItem(item)
case opcode.LDLOC:
item := ctx.local.Get(int(parameter[0]))
v.estack.PushItem(item)
case opcode.STLOC0, opcode.STLOC1, opcode.STLOC2, opcode.STLOC3, opcode.STLOC4, opcode.STLOC5, opcode.STLOC6:
item := v.estack.Pop().Item()
ctx.local.Set(int(op-opcode.STLOC0), item, &v.refs)
case opcode.STLOC:
item := v.estack.Pop().Item()
ctx.local.Set(int(parameter[0]), item, &v.refs)
case opcode.LDARG0, opcode.LDARG1, opcode.LDARG2, opcode.LDARG3, opcode.LDARG4, opcode.LDARG5, opcode.LDARG6:
item := ctx.arguments.Get(int(op - opcode.LDARG0))
v.estack.PushItem(item)
case opcode.LDARG:
item := ctx.arguments.Get(int(parameter[0]))
v.estack.PushItem(item)
case opcode.STARG0, opcode.STARG1, opcode.STARG2, opcode.STARG3, opcode.STARG4, opcode.STARG5, opcode.STARG6:
item := v.estack.Pop().Item()
ctx.arguments.Set(int(op-opcode.STARG0), item, &v.refs)
case opcode.STARG:
item := v.estack.Pop().Item()
ctx.arguments.Set(int(parameter[0]), item, &v.refs)
case opcode.NEWBUFFER:
n := toInt(v.estack.Pop().BigInt())
if n < 0 || n > stackitem.MaxSize {
panic("invalid size")
}
v.estack.PushItem(stackitem.NewBuffer(make([]byte, n)))
case opcode.MEMCPY:
n := toInt(v.estack.Pop().BigInt())
if n < 0 {
panic("invalid size")
}
si := toInt(v.estack.Pop().BigInt())
if si < 0 {
panic("invalid source index")
}
src := v.estack.Pop().Bytes()
if sum := si + n; sum < 0 || sum > len(src) {
panic("size is too big")
}
di := toInt(v.estack.Pop().BigInt())
if di < 0 {
panic("invalid destination index")
}
dst := v.estack.Pop().value.(*stackitem.Buffer).Value().([]byte)
if sum := di + n; sum < 0 || sum > len(dst) {
panic("size is too big")
}
copy(dst[di:], src[si:si+n])
case opcode.CAT:
b := v.estack.Pop().Bytes()
a := v.estack.Pop().Bytes()
l := len(a) + len(b)
if l > stackitem.MaxSize {
panic(fmt.Sprintf("too big item: %d", l))
}
ab := make([]byte, l)
copy(ab, a)
copy(ab[len(a):], b)
v.estack.PushItem(stackitem.NewBuffer(ab))
case opcode.SUBSTR:
l := toInt(v.estack.Pop().BigInt())
if l < 0 {
panic("negative length")
}
o := toInt(v.estack.Pop().BigInt())
if o < 0 {
panic("negative index")
}
s := v.estack.Pop().Bytes()
last := l + o
if last > len(s) {
panic("invalid offset")
}
res := make([]byte, l)
copy(res, s[o:last])
v.estack.PushItem(stackitem.NewBuffer(res))
case opcode.LEFT:
l := toInt(v.estack.Pop().BigInt())
if l < 0 {
panic("negative length")
}
s := v.estack.Pop().Bytes()
if t := len(s); l > t {
panic("size is too big")
}
res := make([]byte, l)
copy(res, s[:l])
v.estack.PushItem(stackitem.NewBuffer(res))
case opcode.RIGHT:
l := toInt(v.estack.Pop().BigInt())
if l < 0 {
panic("negative length")
}
s := v.estack.Pop().Bytes()
res := make([]byte, l)
copy(res, s[len(s)-l:])
v.estack.PushItem(stackitem.NewBuffer(res))
case opcode.DEPTH:
v.estack.PushItem(stackitem.NewBigInteger(big.NewInt(int64(v.estack.Len()))))
case opcode.DROP:
if v.estack.Len() < 1 {
panic("stack is too small")
}
v.estack.Pop()
case opcode.NIP:
if v.estack.Len() < 2 {
panic("no second element found")
}
_ = v.estack.RemoveAt(1)
case opcode.XDROP:
n := toInt(v.estack.Pop().BigInt())
if n < 0 {
panic("invalid length")
}
if v.estack.Len() < n+1 {
panic("bad index")
}
_ = v.estack.RemoveAt(n)
case opcode.CLEAR:
v.estack.Clear()
case opcode.DUP:
v.estack.Push(v.estack.Dup(0))
case opcode.OVER:
if v.estack.Len() < 2 {
panic("no second element found")
}
a := v.estack.Dup(1)
v.estack.Push(a)
case opcode.PICK:
n := toInt(v.estack.Pop().BigInt())
if n < 0 {
panic("negative stack item returned")
}
if v.estack.Len() < n+1 {
panic("no nth element found")
}
a := v.estack.Dup(n)
v.estack.Push(a)
case opcode.TUCK:
if v.estack.Len() < 2 {
panic("too short stack to TUCK")
}
a := v.estack.Dup(0)
v.estack.InsertAt(a, 2)
case opcode.SWAP:
err := v.estack.Swap(1, 0)
if err != nil {
panic(err.Error())
}
case opcode.ROT:
err := v.estack.Roll(2)
if err != nil {
panic(err.Error())
}
case opcode.ROLL:
n := toInt(v.estack.Pop().BigInt())
err := v.estack.Roll(n)
if err != nil {
panic(err.Error())
}
case opcode.REVERSE3, opcode.REVERSE4, opcode.REVERSEN:
n := 3
switch op {
case opcode.REVERSE4:
n = 4
case opcode.REVERSEN:
n = toInt(v.estack.Pop().BigInt())
}
if err := v.estack.ReverseTop(n); err != nil {
panic(err.Error())
}
// Bit operations.
case opcode.INVERT:
i := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Not(i)))
case opcode.AND:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).And(b, a)))
case opcode.OR:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Or(b, a)))
case opcode.XOR:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Xor(b, a)))
case opcode.EQUAL, opcode.NOTEQUAL:
if v.estack.Len() < 2 {
panic("need a pair of elements on the stack")
}
b := v.estack.Pop()
a := v.estack.Pop()
res := stackitem.Bool(a.value.Equals(b.value) == (op == opcode.EQUAL))
v.estack.PushItem(res)
// Numeric operations.
case opcode.SIGN:
x := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(big.NewInt(int64(x.Sign()))))
case opcode.ABS:
x := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Abs(x)))
case opcode.NEGATE:
x := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Neg(x)))
case opcode.INC:
x := v.estack.Pop().BigInt()
a := new(big.Int).Add(x, bigOne)
v.estack.PushItem(stackitem.NewBigInteger(a))
case opcode.DEC:
x := v.estack.Pop().BigInt()
a := new(big.Int).Sub(x, bigOne)
v.estack.PushItem(stackitem.NewBigInteger(a))
case opcode.ADD:
a := v.estack.Pop().BigInt()
b := v.estack.Pop().BigInt()
c := new(big.Int).Add(a, b)
v.estack.PushItem(stackitem.NewBigInteger(c))
case opcode.SUB:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
c := new(big.Int).Sub(a, b)
v.estack.PushItem(stackitem.NewBigInteger(c))
case opcode.MUL:
a := v.estack.Pop().BigInt()
b := v.estack.Pop().BigInt()
c := new(big.Int).Mul(a, b)
v.estack.PushItem(stackitem.NewBigInteger(c))
case opcode.DIV:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Quo(a, b)))
case opcode.MOD:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Rem(a, b)))
case opcode.POW:
exp := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
if ei := exp.Uint64(); !exp.IsUint64() || ei > maxSHLArg {
panic("invalid exponent")
}
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Exp(a, exp, nil)))
case opcode.SQRT:
a := v.estack.Pop().BigInt()
if a.Sign() == -1 {
panic("negative value")
}
v.estack.PushItem(stackitem.NewBigInteger(new(big.Int).Sqrt(a)))
case opcode.MODMUL:
modulus := v.estack.Pop().BigInt()
if modulus.Sign() == 0 {
panic("zero modulus")
}
x2 := v.estack.Pop().BigInt()
x1 := v.estack.Pop().BigInt()
res := new(big.Int).Mul(x1, x2)
v.estack.PushItem(stackitem.NewBigInteger(res.Mod(res, modulus)))
case opcode.MODPOW:
modulus := v.estack.Pop().BigInt()
exponent := v.estack.Pop().BigInt()
base := v.estack.Pop().BigInt()
res := new(big.Int)
switch exponent.Cmp(bigMinusOne) {
case -1:
panic("exponent should be >= -1")
case 0:
if base.Cmp(bigZero) <= 0 {
panic("invalid base")
}
if modulus.Cmp(bigTwo) < 0 {
panic("invalid modulus")
}
if res.ModInverse(base, modulus) == nil {
panic("base and modulus are not relatively prime")
}
case 1:
if modulus.Sign() == 0 {
panic("zero modulus") // https://docs.microsoft.com/en-us/dotnet/api/system.numerics.biginteger.modpow?view=net-6.0#exceptions
}
res.Exp(base, exponent, modulus)
}
v.estack.PushItem(stackitem.NewBigInteger(res))
case opcode.SHL, opcode.SHR:
b := toInt(v.estack.Pop().BigInt())
if b == 0 {
return
} else if b < 0 || b > maxSHLArg {
panic(fmt.Sprintf("operand must be between %d and %d", 0, maxSHLArg))
}
a := v.estack.Pop().BigInt()
var item big.Int
if op == opcode.SHL {
item.Lsh(a, uint(b))
} else {
item.Rsh(a, uint(b))
}
v.estack.PushItem(stackitem.NewBigInteger(&item))
case opcode.NOT:
x := v.estack.Pop().Bool()
v.estack.PushItem(stackitem.Bool(!x))
case opcode.BOOLAND:
b := v.estack.Pop().Bool()
a := v.estack.Pop().Bool()
v.estack.PushItem(stackitem.Bool(a && b))
case opcode.BOOLOR:
b := v.estack.Pop().Bool()
a := v.estack.Pop().Bool()
v.estack.PushItem(stackitem.Bool(a || b))
case opcode.NZ:
x := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.Bool(x.Sign() != 0))
case opcode.NUMEQUAL:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.Bool(a.Cmp(b) == 0))
case opcode.NUMNOTEQUAL:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.Bool(a.Cmp(b) != 0))
case opcode.LT, opcode.LE, opcode.GT, opcode.GE:
eb := v.estack.Pop()
ea := v.estack.Pop()
_, aNil := ea.Item().(stackitem.Null)
_, bNil := eb.Item().(stackitem.Null)
res := !aNil && !bNil
if res {
cmp := ea.BigInt().Cmp(eb.BigInt())
switch op {
case opcode.LT:
res = cmp == -1
case opcode.LE:
res = cmp <= 0
case opcode.GT:
res = cmp == 1
case opcode.GE:
res = cmp >= 0
}
}
v.estack.PushItem(stackitem.Bool(res))
case opcode.MIN:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
val := a
if a.Cmp(b) == 1 {
val = b
}
v.estack.PushItem(stackitem.NewBigInteger(val))
case opcode.MAX:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
val := a
if a.Cmp(b) == -1 {
val = b
}
v.estack.PushItem(stackitem.NewBigInteger(val))
case opcode.WITHIN:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
x := v.estack.Pop().BigInt()
v.estack.PushItem(stackitem.Bool(a.Cmp(x) <= 0 && x.Cmp(b) == -1))
// Object operations
case opcode.NEWARRAY0:
v.estack.PushItem(stackitem.NewArray([]stackitem.Item{}))
case opcode.NEWARRAY, opcode.NEWARRAYT, opcode.NEWSTRUCT:
n := toInt(v.estack.Pop().BigInt())
if n < 0 || n > MaxStackSize {
panic("wrong number of elements")
}
typ := stackitem.AnyT
if op == opcode.NEWARRAYT {
typ = stackitem.Type(parameter[0])
}
items := makeArrayOfType(int(n), typ)
var res stackitem.Item
if op == opcode.NEWSTRUCT {
res = stackitem.NewStruct(items)
} else {
res = stackitem.NewArray(items)
}
v.estack.PushItem(res)
case opcode.NEWSTRUCT0:
v.estack.PushItem(stackitem.NewStruct([]stackitem.Item{}))
case opcode.APPEND:
itemElem := v.estack.Pop()
arrElem := v.estack.Pop()
val := cloneIfStruct(itemElem.value)
switch t := arrElem.value.(type) {
case *stackitem.Array:
t.Append(val)
case *stackitem.Struct:
t.Append(val)
default:
panic("APPEND: not of underlying type Array")
}
v.refs.Add(val)
case opcode.PACKMAP:
n := toInt(v.estack.Pop().BigInt())
if n < 0 || n*2 > v.estack.Len() {
panic("invalid length")
}
items := make([]stackitem.MapElement, n)
for i := 0; i < n; i++ {
key := v.estack.Pop()
validateMapKey(key)
val := v.estack.Pop().value
items[i].Key = key.value
items[i].Value = val
}
v.estack.PushItem(stackitem.NewMapWithValue(items))
case opcode.PACKSTRUCT, opcode.PACK:
n := toInt(v.estack.Pop().BigInt())
if n < 0 || n > v.estack.Len() {
panic("OPACK: invalid length")
}
items := make([]stackitem.Item, n)
for i := 0; i < n; i++ {
items[i] = v.estack.Pop().value
}
var res stackitem.Item
if op == opcode.PACK {
res = stackitem.NewArray(items)
} else {
res = stackitem.NewStruct(items)
}
v.estack.PushItem(res)
case opcode.UNPACK:
e := v.estack.Pop()
var arr []stackitem.Item
var l int
switch t := e.value.(type) {
case *stackitem.Array:
arr = t.Value().([]stackitem.Item)
case *stackitem.Struct:
arr = t.Value().([]stackitem.Item)
case *stackitem.Map:
m := t.Value().([]stackitem.MapElement)
l = len(m)
for i := l - 1; i >= 0; i-- {
v.estack.PushItem(m[i].Value)
v.estack.PushItem(m[i].Key)
}
default:
panic("element is not an array/struct/map")
}
if arr != nil {
l = len(arr)
for i := l - 1; i >= 0; i-- {
v.estack.PushItem(arr[i])
}
}
v.estack.PushItem(stackitem.NewBigInteger(big.NewInt(int64(l))))
case opcode.PICKITEM:
key := v.estack.Pop()
validateMapKey(key)
obj := v.estack.Pop()
switch t := obj.value.(type) {
// Struct and Array items have their underlying value as []Item.
case *stackitem.Array, *stackitem.Struct:
index := toInt(key.BigInt())
arr := t.Value().([]stackitem.Item)
if index < 0 || index >= len(arr) {
msg := fmt.Sprintf("The value %d is out of range.", index)
v.throw(stackitem.NewByteArray([]byte(msg)))
return
}
item := arr[index].Dup()
v.estack.PushItem(item)
case *stackitem.Map:
index := t.Index(key.Item())
if index < 0 {
v.throw(stackitem.NewByteArray([]byte("Key not found in Map")))
return
}
v.estack.PushItem(t.Value().([]stackitem.MapElement)[index].Value.Dup())
default:
index := toInt(key.BigInt())
arr := obj.Bytes()
if index < 0 || index >= len(arr) {
msg := fmt.Sprintf("The value %d is out of range.", index)
v.throw(stackitem.NewByteArray([]byte(msg)))
return
}
item := arr[index]
v.estack.PushItem(stackitem.NewBigInteger(big.NewInt(int64(item))))
}
case opcode.SETITEM:
item := v.estack.Pop().value
key := v.estack.Pop()
validateMapKey(key)
obj := v.estack.Pop()
switch t := obj.value.(type) {
// Struct and Array items have their underlying value as []Item.
case *stackitem.Array, *stackitem.Struct:
arr := t.Value().([]stackitem.Item)
index := toInt(key.BigInt())
if index < 0 || index >= len(arr) {
msg := fmt.Sprintf("The value %d is out of range.", index)
v.throw(stackitem.NewByteArray([]byte(msg)))
return
}
if t.(stackitem.Immutable).IsReadOnly() {
panic(stackitem.ErrReadOnly)
}
v.refs.Remove(arr[index])
arr[index] = item
v.refs.Add(arr[index])
case *stackitem.Map:
if t.IsReadOnly() {
panic(stackitem.ErrReadOnly)
}
if i := t.Index(key.value); i >= 0 {
v.refs.Remove(t.Value().([]stackitem.MapElement)[i].Value)
} else {
v.refs.Add(key.value)
}
t.Add(key.value, item)
v.refs.Add(item)
case *stackitem.Buffer:
index := toInt(key.BigInt())
if index < 0 || index >= t.Len() {
msg := fmt.Sprintf("The value %d is out of range.", index)
v.throw(stackitem.NewByteArray([]byte(msg)))
return
}
bi, err := item.TryInteger()
b := toInt(bi)
if err != nil || b < math.MinInt8 || b > math.MaxUint8 {
panic("invalid value")
}
t.Value().([]byte)[index] = byte(b)
default:
panic(fmt.Sprintf("SETITEM: invalid item type %s", t))
}
case opcode.REVERSEITEMS:
item := v.estack.Pop()
switch t := item.value.(type) {
case *stackitem.Array, *stackitem.Struct:
if t.(stackitem.Immutable).IsReadOnly() {
panic(stackitem.ErrReadOnly)
}
a := t.Value().([]stackitem.Item)
for i, j := 0, len(a)-1; i < j; i, j = i+1, j-1 {
a[i], a[j] = a[j], a[i]
}
case *stackitem.Buffer:
b := t.Value().([]byte)
slice.Reverse(b)
default:
panic(fmt.Sprintf("invalid item type %s", t))
}
case opcode.REMOVE:
key := v.estack.Pop()
validateMapKey(key)
elem := v.estack.Pop()
switch t := elem.value.(type) {
case *stackitem.Array:
a := t.Value().([]stackitem.Item)
k := toInt(key.BigInt())
if k < 0 || k >= len(a) {
panic("REMOVE: invalid index")
}
toRemove := a[k]
t.Remove(k)
v.refs.Remove(toRemove)
case *stackitem.Struct:
a := t.Value().([]stackitem.Item)
k := toInt(key.BigInt())
if k < 0 || k >= len(a) {
panic("REMOVE: invalid index")
}
toRemove := a[k]
t.Remove(k)
v.refs.Remove(toRemove)
case *stackitem.Map:
index := t.Index(key.Item())
// NEO 2.0 doesn't error on missing key.
if index >= 0 {
elems := t.Value().([]stackitem.MapElement)
key := elems[index].Key
val := elems[index].Value
t.Drop(index)
v.refs.Remove(key)
v.refs.Remove(val)
}
default:
panic("REMOVE: invalid type")
}
case opcode.CLEARITEMS:
elem := v.estack.Pop()
switch t := elem.value.(type) {
case *stackitem.Array:
if t.IsReadOnly() {
panic(stackitem.ErrReadOnly)
}
for _, item := range t.Value().([]stackitem.Item) {
v.refs.Remove(item)
}
t.Clear()
case *stackitem.Struct:
if t.IsReadOnly() {
panic(stackitem.ErrReadOnly)
}
for _, item := range t.Value().([]stackitem.Item) {
v.refs.Remove(item)
}
t.Clear()
case *stackitem.Map:
if t.IsReadOnly() {
panic(stackitem.ErrReadOnly)
}
elems := t.Value().([]stackitem.MapElement)
for i := range elems {
v.refs.Remove(elems[i].Key)
v.refs.Remove(elems[i].Value)
}
t.Clear()
default:
panic("CLEARITEMS: invalid type")
}
case opcode.POPITEM:
arr := v.estack.Pop().Item()
elems := arr.Value().([]stackitem.Item)
index := len(elems) - 1
elem := elems[index]
v.estack.PushItem(elem) // push item on stack firstly, to match the reference behaviour.
switch item := arr.(type) {
case *stackitem.Array:
item.Remove(index)
case *stackitem.Struct:
item.Remove(index)
}
v.refs.Remove(elem)
case opcode.SIZE:
elem := v.estack.Pop()
var res int
// Cause there is no native (byte) item type here, we need to check
// the type of the item for array size operations.
switch t := elem.Value().(type) {
case []stackitem.Item:
res = len(t)
case []stackitem.MapElement:
res = len(t)
default:
res = len(elem.Bytes())
}
v.estack.PushItem(stackitem.NewBigInteger(big.NewInt(int64(res))))
case opcode.JMP, opcode.JMPL, opcode.JMPIF, opcode.JMPIFL, opcode.JMPIFNOT, opcode.JMPIFNOTL,
opcode.JMPEQ, opcode.JMPEQL, opcode.JMPNE, opcode.JMPNEL,
opcode.JMPGT, opcode.JMPGTL, opcode.JMPGE, opcode.JMPGEL,
opcode.JMPLT, opcode.JMPLTL, opcode.JMPLE, opcode.JMPLEL:
offset := getJumpOffset(ctx, parameter)
cond := true
switch op {
case opcode.JMP, opcode.JMPL:
case opcode.JMPIF, opcode.JMPIFL, opcode.JMPIFNOT, opcode.JMPIFNOTL:
cond = v.estack.Pop().Bool() == (op == opcode.JMPIF || op == opcode.JMPIFL)
default:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
cond = getJumpCondition(op, a, b)
}
if cond {
ctx.Jump(offset)
}
case opcode.CALL, opcode.CALLL:
// Note: jump offset must be calculated regarding the new context,
// but it is cloned and thus has the same script and instruction pointer.
v.call(ctx, getJumpOffset(ctx, parameter))
case opcode.CALLA:
ptr := v.estack.Pop().Item().(*stackitem.Pointer)
if ptr.ScriptHash() != ctx.ScriptHash() {
panic("invalid script in pointer")
}
v.call(ctx, ptr.Position())
case opcode.CALLT:
id := int32(binary.LittleEndian.Uint16(parameter))
if err := v.LoadToken(id); err != nil {
panic(err)
}
case opcode.SYSCALL:
interopID := GetInteropID(parameter)
if v.SyscallHandler == nil {
panic("vm's SyscallHandler is not initialized")
}
err := v.SyscallHandler(v, interopID)
if err != nil {
panic(fmt.Sprintf("failed to invoke syscall %d: %s", interopID, err))
}
case opcode.RET:
oldCtx := v.istack.Pop().value.(*Context)
oldEstack := v.estack
v.unloadContext(oldCtx)
if v.istack.Len() == 0 {
v.state = vmstate.Halt
break
}
newEstack := v.Context().sc.estack
if oldEstack != newEstack {
if oldCtx.retCount >= 0 && oldEstack.Len() != oldCtx.retCount {
panic(fmt.Errorf("invalid return values count: expected %d, got %d",
oldCtx.retCount, oldEstack.Len()))
}
rvcount := oldEstack.Len()
for i := rvcount; i > 0; i-- {
elem := oldEstack.RemoveAt(i - 1)
newEstack.Push(elem)
}
v.estack = newEstack
}
case opcode.NEWMAP:
v.estack.PushItem(stackitem.NewMap())
case opcode.KEYS:
if v.estack.Len() == 0 {
panic("no argument")
}
item := v.estack.Pop()
m, ok := item.value.(*stackitem.Map)
if !ok {
panic("not a Map")
}
arr := make([]stackitem.Item, 0, m.Len())
for k := range m.Value().([]stackitem.MapElement) {
arr = append(arr, m.Value().([]stackitem.MapElement)[k].Key.Dup())
}
v.estack.PushItem(stackitem.NewArray(arr))
case opcode.VALUES:
if v.estack.Len() == 0 {
panic("no argument")
}
item := v.estack.Pop()
var arr []stackitem.Item
switch t := item.value.(type) {
case *stackitem.Array, *stackitem.Struct:
src := t.Value().([]stackitem.Item)
arr = make([]stackitem.Item, len(src))
for i := range src {
arr[i] = cloneIfStruct(src[i])
}
case *stackitem.Map:
arr = make([]stackitem.Item, 0, t.Len())
for k := range t.Value().([]stackitem.MapElement) {
arr = append(arr, cloneIfStruct(t.Value().([]stackitem.MapElement)[k].Value))
}
default:
panic("not a Map, Array or Struct")
}
v.estack.PushItem(stackitem.NewArray(arr))
case opcode.HASKEY:
if v.estack.Len() < 2 {
panic("not enough arguments")
}
key := v.estack.Pop()
validateMapKey(key)
c := v.estack.Pop()
var res bool
switch t := c.value.(type) {
case *stackitem.Array, *stackitem.Struct:
index := toInt(key.BigInt())
if index < 0 {
panic("negative index")
}
res = index < len(c.Array())
case *stackitem.Map:
res = t.Has(key.Item())
case *stackitem.Buffer, *stackitem.ByteArray:
index := toInt(key.BigInt())
if index < 0 {
panic("negative index")
}
res = index < len(t.Value().([]byte))
default:
panic("wrong collection type")
}
v.estack.PushItem(stackitem.Bool(res))
case opcode.NOP:
// unlucky ^^
case opcode.THROW:
v.throw(v.estack.Pop().Item())
case opcode.ABORT:
panic("ABORT")
case opcode.ASSERT:
if !v.estack.Pop().Bool() {
panic("ASSERT failed")
}
case opcode.TRY, opcode.TRYL:
catchP, finallyP := getTryParams(op, parameter)
if ctx.tryStack.Len() >= MaxTryNestingDepth {
panic("maximum TRY depth exceeded")
}
cOffset := getJumpOffset(ctx, catchP)
fOffset := getJumpOffset(ctx, finallyP)
if cOffset == ctx.ip && fOffset == ctx.ip {
panic("invalid offset for TRY*")
} else if cOffset == ctx.ip {
cOffset = -1
} else if fOffset == ctx.ip {
fOffset = -1
}
eCtx := newExceptionHandlingContext(cOffset, fOffset)
ctx.tryStack.PushItem(eCtx)
case opcode.ENDTRY, opcode.ENDTRYL:
eCtx := ctx.tryStack.Peek(0).Value().(*exceptionHandlingContext)
if eCtx.State == eFinally {
panic("invalid exception handling state during ENDTRY*")
}
eOffset := getJumpOffset(ctx, parameter)
if eCtx.HasFinally() {
eCtx.State = eFinally
eCtx.EndOffset = eOffset
eOffset = eCtx.FinallyOffset
} else {
ctx.tryStack.Pop()
}
ctx.Jump(eOffset)
case opcode.ENDFINALLY:
if v.uncaughtException != nil {
v.handleException()
return
}
eCtx := ctx.tryStack.Pop().Value().(*exceptionHandlingContext)
ctx.Jump(eCtx.EndOffset)
default:
panic(fmt.Sprintf("unknown opcode %s", op.String()))
}
return
}
func (v *VM) unloadContext(ctx *Context) {
if ctx.local != nil {
ctx.local.ClearRefs(&v.refs)
}
if ctx.arguments != nil {
ctx.arguments.ClearRefs(&v.refs)
}
currCtx := v.Context()
if currCtx == nil || ctx.sc != currCtx.sc {
if ctx.sc.static != nil {
ctx.sc.static.ClearRefs(&v.refs)
}
if ctx.sc.onUnload != nil {
err := ctx.sc.onUnload(ctx, v.uncaughtException == nil)
if err != nil {
errMessage := fmt.Sprintf("context unload callback failed: %s", err)
if v.uncaughtException != nil {
errMessage = fmt.Sprintf("%s, uncaught exception: %s", errMessage, v.uncaughtException)
}
panic(errors.New(errMessage))
}
}
}
}
// getTryParams splits TRY(L) instruction parameter into offsets for catch and finally blocks.
func getTryParams(op opcode.Opcode, p []byte) ([]byte, []byte) {
i := 1
if op == opcode.TRYL {
i = 4
}
return p[:i], p[i:]
}
// getJumpCondition performs opcode specific comparison of a and b.
func getJumpCondition(op opcode.Opcode, a, b *big.Int) bool {
cmp := a.Cmp(b)
switch op {
case opcode.JMPEQ, opcode.JMPEQL:
return cmp == 0
case opcode.JMPNE, opcode.JMPNEL:
return cmp != 0
case opcode.JMPGT, opcode.JMPGTL:
return cmp > 0
case opcode.JMPGE, opcode.JMPGEL:
return cmp >= 0
case opcode.JMPLT, opcode.JMPLTL:
return cmp < 0
case opcode.JMPLE, opcode.JMPLEL:
return cmp <= 0
default:
panic(fmt.Sprintf("invalid JMP* opcode: %s", op))
}
}
func (v *VM) throw(item stackitem.Item) {
v.uncaughtException = item
v.handleException()
}
// Call calls a method by offset using the new execution context.
func (v *VM) Call(offset int) {
v.call(v.Context(), offset)
}
// call is an internal representation of Call, which does not
// affect the invocation counter and is only used by vm
// package.
func (v *VM) call(ctx *Context, offset int) {
v.checkInvocationStackSize()
newCtx := &Context{
sc: ctx.sc,
retCount: -1,
tryStack: ctx.tryStack,
}
// New context -> new exception handlers.
newCtx.tryStack.elems = ctx.tryStack.elems[len(ctx.tryStack.elems):]
v.istack.PushItem(newCtx)
newCtx.Jump(offset)
}
// getJumpOffset returns an instruction number in the current context
// to which JMP should be performed.
// parameter should have length either 1 or 4 and
// is interpreted as little-endian.
func getJumpOffset(ctx *Context, parameter []byte) int {
offset, _, err := calcJumpOffset(ctx, parameter)
if err != nil {
panic(err)
}
return offset
}
// calcJumpOffset returns an absolute and a relative offset of JMP/CALL/TRY instructions
// either in a short (1-byte) or a long (4-byte) form.
func calcJumpOffset(ctx *Context, parameter []byte) (int, int, error) {
var rOffset int32
switch l := len(parameter); l {
case 1:
rOffset = int32(int8(parameter[0]))
case 4:
rOffset = int32(binary.LittleEndian.Uint32(parameter))
default:
_, curr := ctx.CurrInstr()
return 0, 0, fmt.Errorf("invalid %s parameter length: %d", curr, l)
}
offset := ctx.ip + int(rOffset)
if offset < 0 || offset > len(ctx.sc.prog) {
return 0, 0, fmt.Errorf("invalid offset %d ip at %d", offset, ctx.ip)
}
return offset, int(rOffset), nil
}
func (v *VM) handleException() {
for pop := 0; pop < v.istack.Len(); pop++ {
ictxv := v.istack.Peek(pop)
ictx := ictxv.value.(*Context)
for j := 0; j < ictx.tryStack.Len(); j++ {
e := ictx.tryStack.Peek(j)
ectx := e.Value().(*exceptionHandlingContext)
if ectx.State == eFinally || (ectx.State == eCatch && !ectx.HasFinally()) {
ictx.tryStack.Pop()
j = -1
continue
}
for i := 0; i < pop; i++ {
ctx := v.istack.Pop().value.(*Context)
v.unloadContext(ctx)
}
if ectx.State == eTry && ectx.HasCatch() {
ectx.State = eCatch
v.estack.PushItem(v.uncaughtException)
v.uncaughtException = nil
ictx.Jump(ectx.CatchOffset)
} else {
ectx.State = eFinally
ictx.Jump(ectx.FinallyOffset)
}
return
}
}
throwUnhandledException(v.uncaughtException)
}
// throwUnhandledException gets an exception message from the provided stackitem and panics.
func throwUnhandledException(item stackitem.Item) {
msg := "unhandled exception"
switch item.Type() {
case stackitem.ArrayT:
if arr := item.Value().([]stackitem.Item); len(arr) > 0 {
data, err := arr[0].TryBytes()
if err == nil {
msg = fmt.Sprintf("%s: %q", msg, string(data))
}
}
default:
data, err := item.TryBytes()
if err == nil {
msg = fmt.Sprintf("%s: %q", msg, string(data))
}
}
panic(msg)
}
// CheckMultisigPar checks if the sigs contains sufficient valid signatures.
func CheckMultisigPar(v *VM, curve elliptic.Curve, h []byte, pkeys [][]byte, sigs [][]byte) bool {
if len(sigs) == 1 {
return checkMultisig1(v, curve, h, pkeys, sigs[0])
}
k1, k2 := 0, len(pkeys)-1
s1, s2 := 0, len(sigs)-1
type task struct {
pub *keys.PublicKey
signum int
}
type verify struct {
ok bool
signum int
}
worker := func(ch <-chan task, result chan verify) {
for {
t, ok := <-ch
if !ok {
return
}
result <- verify{
signum: t.signum,
ok: t.pub.Verify(sigs[t.signum], h),
}
}
}
const workerCount = 3
tasks := make(chan task, 2)
results := make(chan verify, len(sigs))
for i := 0; i < workerCount; i++ {
go worker(tasks, results)
}
tasks <- task{pub: bytesToPublicKey(pkeys[k1], curve), signum: s1}
tasks <- task{pub: bytesToPublicKey(pkeys[k2], curve), signum: s2}
sigok := true
taskCount := 2
loop:
for r := range results {
goingForward := true
taskCount--
if r.signum == s2 {
goingForward = false
}
if k1+1 == k2 {
sigok = r.ok && s1+1 == s2
if taskCount != 0 && sigok {
continue
}
break loop
} else if r.ok {
if s1+1 == s2 {
if taskCount != 0 && sigok {
continue
}
break loop
}
if goingForward {
s1++
} else {
s2--
}
}
var nextSig, nextKey int
if goingForward {
k1++
nextSig = s1
nextKey = k1
} else {
k2--
nextSig = s2
nextKey = k2
}
taskCount++
tasks <- task{pub: bytesToPublicKey(pkeys[nextKey], curve), signum: nextSig}
}
close(tasks)
return sigok
}
func checkMultisig1(v *VM, curve elliptic.Curve, h []byte, pkeys [][]byte, sig []byte) bool {
for i := range pkeys {
pkey := bytesToPublicKey(pkeys[i], curve)
if pkey.Verify(sig, h) {
return true
}
}
return false
}
func cloneIfStruct(item stackitem.Item) stackitem.Item {
switch it := item.(type) {
case *stackitem.Struct:
ret, err := it.Clone()
if err != nil {
panic(err)
}
return ret
default:
return it
}
}
func makeArrayOfType(n int, typ stackitem.Type) []stackitem.Item {
if !typ.IsValid() {
panic(fmt.Sprintf("invalid stack item type: %d", typ))
}
items := make([]stackitem.Item, n)
for i := range items {
switch typ {
case stackitem.BooleanT:
items[i] = stackitem.NewBool(false)
case stackitem.IntegerT:
items[i] = stackitem.NewBigInteger(big.NewInt(0))
case stackitem.ByteArrayT:
items[i] = stackitem.NewByteArray([]byte{})
default:
items[i] = stackitem.Null{}
}
}
return items
}
func validateMapKey(key Element) {
item := key.Item()
if item == nil {
panic("no key found")
}
if err := stackitem.IsValidMapKey(item); err != nil {
panic(err)
}
}
func (v *VM) checkInvocationStackSize() {
if v.istack.Len() >= MaxInvocationStackSize {
panic("invocation stack is too big")
}
}
// bytesToPublicKey is a helper deserializing keys using cache and panicing on
// error.
func bytesToPublicKey(b []byte, curve elliptic.Curve) *keys.PublicKey {
pkey, err := keys.NewPublicKeyFromBytes(b, curve)
if err != nil {
panic(err.Error())
}
return pkey
}
// GetCallingScriptHash implements the ScriptHashGetter interface.
func (v *VM) GetCallingScriptHash() util.Uint160 {
return v.Context().sc.callingScriptHash
}
// GetEntryScriptHash implements the ScriptHashGetter interface.
func (v *VM) GetEntryScriptHash() util.Uint160 {
return v.getContextScriptHash(v.istack.Len() - 1)
}
// GetCurrentScriptHash implements the ScriptHashGetter interface.
func (v *VM) GetCurrentScriptHash() util.Uint160 {
return v.getContextScriptHash(0)
}
// toInt converts an item to a 32-bit int.
func toInt(i *big.Int) int {
if !i.IsInt64() {
panic("not an int32")
}
n := i.Int64()
if n < math.MinInt32 || n > math.MaxInt32 {
panic("not an int32")
}
return int(n)
}