neo-go/pkg/core/interop/context.go
Roman Khimov 7589733017 config: add a special Blockchain type to configure Blockchain
And include some node-specific configurations there with backwards
compatibility. Note that in the future we'll remove Ledger's
fields from the ProtocolConfiguration and it'll be possible to access them in
Blockchain directly (not via .Ledger).

The other option tried was using two configuration types separately, but that
incurs more changes to the codebase, single structure that behaves almost like
the old one is better for backwards compatibility.

Fixes #2676.
2022-12-07 17:35:53 +03:00

413 lines
12 KiB
Go

package interop
import (
"context"
"encoding/binary"
"errors"
"fmt"
"sort"
"strings"
"github.com/nspcc-dev/neo-go/pkg/config"
"github.com/nspcc-dev/neo-go/pkg/core/block"
"github.com/nspcc-dev/neo-go/pkg/core/dao"
"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/core/storage"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"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/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
"go.uber.org/zap"
)
const (
// DefaultBaseExecFee specifies the default multiplier for opcode and syscall prices.
DefaultBaseExecFee = 30
)
// Ledger is the interface to Blockchain required for Context functionality.
type Ledger interface {
BlockHeight() uint32
CurrentBlockHash() util.Uint256
GetBlock(hash util.Uint256) (*block.Block, error)
GetConfig() config.Blockchain
GetHeaderHash(uint32) util.Uint256
}
// Context represents context in which interops are executed.
type Context struct {
Chain Ledger
Container hash.Hashable
Network uint32
Hardforks map[string]uint32
Natives []Contract
Trigger trigger.Type
Block *block.Block
NonceData [16]byte
Tx *transaction.Transaction
DAO *dao.Simple
Notifications []state.NotificationEvent
Log *zap.Logger
VM *vm.VM
Functions []Function
Invocations map[util.Uint160]int
cancelFuncs []context.CancelFunc
getContract func(*dao.Simple, util.Uint160) (*state.Contract, error)
baseExecFee int64
baseStorageFee int64
loadToken func(ic *Context, id int32) error
GetRandomCounter uint32
signers []transaction.Signer
}
// NewContext returns new interop context.
func NewContext(trigger trigger.Type, bc Ledger, d *dao.Simple, baseExecFee, baseStorageFee int64,
getContract func(*dao.Simple, util.Uint160) (*state.Contract, error), natives []Contract,
loadTokenFunc func(ic *Context, id int32) error,
block *block.Block, tx *transaction.Transaction, log *zap.Logger) *Context {
dao := d.GetPrivate()
cfg := bc.GetConfig().ProtocolConfiguration
return &Context{
Chain: bc,
Network: uint32(cfg.Magic),
Hardforks: cfg.Hardforks,
Natives: natives,
Trigger: trigger,
Block: block,
Tx: tx,
DAO: dao,
Log: log,
Invocations: make(map[util.Uint160]int),
getContract: getContract,
baseExecFee: baseExecFee,
baseStorageFee: baseStorageFee,
loadToken: loadTokenFunc,
}
}
// InitNonceData initializes nonce to be used in `GetRandom` calculations.
func (ic *Context) InitNonceData() {
if tx, ok := ic.Container.(*transaction.Transaction); ok {
copy(ic.NonceData[:], tx.Hash().BytesBE())
}
if ic.Block != nil {
nonce := ic.Block.Nonce
nonce ^= binary.LittleEndian.Uint64(ic.NonceData[:])
binary.LittleEndian.PutUint64(ic.NonceData[:], nonce)
}
}
// UseSigners allows overriding signers used in this context.
func (ic *Context) UseSigners(s []transaction.Signer) {
ic.signers = s
}
// Signers returns signers witnessing the current execution context.
func (ic *Context) Signers() []transaction.Signer {
if ic.signers != nil {
return ic.signers
}
if ic.Tx != nil {
return ic.Tx.Signers
}
return nil
}
// Function binds function name, id with the function itself and the price,
// it's supposed to be inited once for all interopContexts, so it doesn't use
// vm.InteropFuncPrice directly.
type Function struct {
ID uint32
Name string
Func func(*Context) error
// ParamCount is a number of function parameters.
ParamCount int
Price int64
// RequiredFlags is a set of flags which must be set during script invocations.
// Default value is NoneFlag i.e. no flags are required.
RequiredFlags callflag.CallFlag
}
// Method is a signature for a native method.
type Method = func(ic *Context, args []stackitem.Item) stackitem.Item
// MethodAndPrice is a native-contract method descriptor.
type MethodAndPrice struct {
Func Method
MD *manifest.Method
CPUFee int64
StorageFee int64
SyscallOffset int
RequiredFlags callflag.CallFlag
}
// Contract is an interface for all native contracts.
type Contract interface {
Initialize(*Context) error
Metadata() *ContractMD
OnPersist(*Context) error
PostPersist(*Context) error
}
// ContractMD represents a native contract instance.
type ContractMD struct {
state.NativeContract
Name string
Methods []MethodAndPrice
}
// NewContractMD returns Contract with the specified list of methods.
func NewContractMD(name string, id int32) *ContractMD {
c := &ContractMD{Name: name}
c.ID = id
// NEF is now stored in the contract state and affects state dump.
// Therefore, values are taken from C# node.
c.NEF.Header.Compiler = "neo-core-v3.0"
c.NEF.Header.Magic = nef.Magic
c.NEF.Tokens = []nef.MethodToken{} // avoid `nil` result during JSON marshalling
c.Hash = state.CreateNativeContractHash(c.Name)
c.Manifest = *manifest.DefaultManifest(name)
return c
}
// UpdateHash creates a native contract script and updates hash.
func (c *ContractMD) UpdateHash() {
w := io.NewBufBinWriter()
for i := range c.Methods {
offset := w.Len()
c.Methods[i].MD.Offset = offset
c.Manifest.ABI.Methods[i].Offset = offset
emit.Int(w.BinWriter, 0)
c.Methods[i].SyscallOffset = w.Len()
emit.Syscall(w.BinWriter, interopnames.SystemContractCallNative)
emit.Opcodes(w.BinWriter, opcode.RET)
}
if w.Err != nil {
panic(fmt.Errorf("can't create native contract script: %w", w.Err))
}
c.NEF.Script = w.Bytes()
c.NEF.Checksum = c.NEF.CalculateChecksum()
}
// AddMethod adds a new method to a native contract.
func (c *ContractMD) AddMethod(md *MethodAndPrice, desc *manifest.Method) {
md.MD = desc
desc.Safe = md.RequiredFlags&(callflag.All^callflag.ReadOnly) == 0
index := sort.Search(len(c.Manifest.ABI.Methods), func(i int) bool {
md := c.Manifest.ABI.Methods[i]
if md.Name != desc.Name {
return md.Name >= desc.Name
}
return len(md.Parameters) > len(desc.Parameters)
})
c.Manifest.ABI.Methods = append(c.Manifest.ABI.Methods, manifest.Method{})
copy(c.Manifest.ABI.Methods[index+1:], c.Manifest.ABI.Methods[index:])
c.Manifest.ABI.Methods[index] = *desc
// Cache follows the same order.
c.Methods = append(c.Methods, MethodAndPrice{})
copy(c.Methods[index+1:], c.Methods[index:])
c.Methods[index] = *md
}
// GetMethodByOffset returns method with the provided offset.
// Offset is offset of `System.Contract.CallNative` syscall.
func (c *ContractMD) GetMethodByOffset(offset int) (MethodAndPrice, bool) {
for k := range c.Methods {
if c.Methods[k].SyscallOffset == offset {
return c.Methods[k], true
}
}
return MethodAndPrice{}, false
}
// GetMethod returns method `name` with the specified number of parameters.
func (c *ContractMD) GetMethod(name string, paramCount int) (MethodAndPrice, bool) {
index := sort.Search(len(c.Methods), func(i int) bool {
md := c.Methods[i]
res := strings.Compare(name, md.MD.Name)
switch res {
case -1, 1:
return res == -1
default:
return paramCount <= len(md.MD.Parameters)
}
})
if index < len(c.Methods) {
md := c.Methods[index]
if md.MD.Name == name && (paramCount == -1 || len(md.MD.Parameters) == paramCount) {
return md, true
}
}
return MethodAndPrice{}, false
}
// AddEvent adds a new event to the native contract.
func (c *ContractMD) AddEvent(name string, ps ...manifest.Parameter) {
c.Manifest.ABI.Events = append(c.Manifest.ABI.Events, manifest.Event{
Name: name,
Parameters: ps,
})
}
// IsActive returns true if the contract was deployed by the specified height.
func (c *ContractMD) IsActive(height uint32) bool {
history := c.UpdateHistory
return len(history) != 0 && history[0] <= height
}
// Sort sorts interop functions by id.
func Sort(fs []Function) {
sort.Slice(fs, func(i, j int) bool { return fs[i].ID < fs[j].ID })
}
// GetContract returns a contract by its hash in the current interop context.
func (ic *Context) GetContract(hash util.Uint160) (*state.Contract, error) {
return ic.getContract(ic.DAO, hash)
}
// GetFunction returns metadata for interop with the specified id.
func (ic *Context) GetFunction(id uint32) *Function {
n := sort.Search(len(ic.Functions), func(i int) bool {
return ic.Functions[i].ID >= id
})
if n < len(ic.Functions) && ic.Functions[n].ID == id {
return &ic.Functions[n]
}
return nil
}
// BaseExecFee represents factor to multiply syscall prices with.
func (ic *Context) BaseExecFee() int64 {
return ic.baseExecFee
}
// BaseStorageFee represents price for storing one byte of data in the contract storage.
func (ic *Context) BaseStorageFee() int64 {
return ic.baseStorageFee
}
// LoadToken wraps externally provided load-token loading function providing it with context,
// this function can then be easily used by VM.
func (ic *Context) LoadToken(id int32) error {
return ic.loadToken(ic, id)
}
// SyscallHandler handles syscall with id.
func (ic *Context) SyscallHandler(_ *vm.VM, id uint32) error {
f := ic.GetFunction(id)
if f == nil {
return errors.New("syscall not found")
}
cf := ic.VM.Context().GetCallFlags()
if !cf.Has(f.RequiredFlags) {
return fmt.Errorf("missing call flags: %05b vs %05b", cf, f.RequiredFlags)
}
if !ic.VM.AddGas(f.Price * ic.BaseExecFee()) {
return errors.New("insufficient amount of gas")
}
return f.Func(ic)
}
// SpawnVM spawns a new VM with the specified gas limit and set context.VM field.
func (ic *Context) SpawnVM() *vm.VM {
v := vm.NewWithTrigger(ic.Trigger)
ic.initVM(v)
return v
}
func (ic *Context) initVM(v *vm.VM) {
v.LoadToken = ic.LoadToken
v.GasLimit = -1
v.SyscallHandler = ic.SyscallHandler
v.SetPriceGetter(ic.GetPrice)
ic.VM = v
}
// ReuseVM resets given VM and allows to reuse it in the current context.
func (ic *Context) ReuseVM(v *vm.VM) {
v.Reset(ic.Trigger)
ic.initVM(v)
}
// RegisterCancelFunc adds the given function to the list of functions to be called after the VM
// finishes script execution.
func (ic *Context) RegisterCancelFunc(f context.CancelFunc) {
if f != nil {
ic.cancelFuncs = append(ic.cancelFuncs, f)
}
}
// Finalize calls all registered cancel functions to release the occupied resources.
func (ic *Context) Finalize() {
for _, f := range ic.cancelFuncs {
f()
}
ic.cancelFuncs = nil
}
// Exec executes loaded VM script and calls registered finalizers to release the occupied resources.
func (ic *Context) Exec() error {
defer ic.Finalize()
return ic.VM.Run()
}
// BlockHeight returns current block height got from Context's block if it's set.
func (ic *Context) BlockHeight() uint32 {
if ic.Block != nil {
return ic.Block.Index - 1 // Persisting block is not yet stored.
}
return ic.Chain.BlockHeight()
}
// CurrentBlockHash returns current block hash got from Context's block if it's set.
func (ic *Context) CurrentBlockHash() util.Uint256 {
if ic.Block != nil {
return ic.Chain.GetHeaderHash(ic.Block.Index - 1) // Persisting block is not yet stored.
}
return ic.Chain.CurrentBlockHash()
}
// GetBlock returns block if it exists and available at the current Context's height.
func (ic *Context) GetBlock(hash util.Uint256) (*block.Block, error) {
block, err := ic.Chain.GetBlock(hash)
if err != nil {
return nil, err
}
if block.Index > ic.BlockHeight() {
return nil, storage.ErrKeyNotFound
}
return block, nil
}
// IsHardforkEnabled tells whether specified hard-fork enabled at the current context height.
func (ic *Context) IsHardforkEnabled(hf config.Hardfork) bool {
height, ok := ic.Hardforks[hf.String()]
if ok {
return ic.BlockHeight() >= height
}
return len(ic.Hardforks) == 0 // Enable each hard-fork by default.
}
// AddNotification creates notification event and appends it to the notification list.
func (ic *Context) AddNotification(hash util.Uint160, name string, item *stackitem.Array) {
ic.Notifications = append(ic.Notifications, state.NotificationEvent{
ScriptHash: hash,
Name: name,
Item: item,
})
}