/
instance_runtime.go
167 lines (146 loc) · 3.86 KB
/
instance_runtime.go
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package wasmtime
import (
"context"
"encoding/binary"
"github.com/bytecodealliance/wasmtime-go/v8"
"github.com/pkg/errors"
"github.com/machinefi/w3bstream/pkg/depends/kit/logr"
)
var (
ErrNotLinked = errors.New("not linked")
ErrAlreadyInstantiated = errors.New("already instantiated")
ErrNotInstantiated = errors.New("not instantiated")
ErrFuncNotImported = errors.New("func not imported")
ErrAlreadyLinked = errors.New("already linked")
engine = wasmtime.NewEngineWithConfig(wasmtime.NewConfig())
)
type (
Runtime struct {
module *wasmtime.Module
linker *wasmtime.Linker
store *wasmtime.Store
instance *wasmtime.Instance
}
)
func NewRuntime() *Runtime {
return &Runtime{}
}
func (rt *Runtime) Link(lk ABILinker, code []byte) error {
if rt.module != nil {
return ErrAlreadyLinked
}
linker := wasmtime.NewLinker(engine)
if err := lk.LinkABI(func(module, name string, fn interface{}) error {
return linker.FuncWrap(module, name, fn)
}); err != nil {
return err
}
if err := linker.DefineWasi(); err != nil {
return err
}
rt.linker = linker
module, err := wasmtime.NewModule(engine, code)
if err != nil {
return err
}
rt.module = module
return nil
}
func (rt *Runtime) Instantiate(ctx context.Context) error {
ctx, l := logr.Start(ctx, "modules.vm.wasmtime.Runtime.Instantiate")
defer l.End()
if rt.module == nil {
return ErrNotLinked
}
if rt.instance != nil {
return ErrAlreadyInstantiated
}
store := wasmtime.NewStore(engine)
store.SetWasi(wasmtime.NewWasiConfig())
instance, err := rt.linker.Instantiate(store, rt.module)
if err != nil {
return err
}
rt.instance = instance
rt.store = store
return nil
}
func (rt *Runtime) Deinstantiate(ctx context.Context) {
ctx, l := logr.Start(ctx, "modules.vm.wasmtime.Runtime.Deinstantiate")
defer l.End()
rt.instance = nil
rt.store = nil
}
func (rt *Runtime) newMemory() []byte {
return rt.instance.GetExport(rt.store, "memory").Memory().UnsafeData(rt.store)
}
func (rt *Runtime) alloc(size int32) (int32, []byte, error) {
fn := rt.instance.GetExport(rt.store, "alloc")
if fn == nil {
return 0, nil, errors.New("alloc is nil")
}
result, err := fn.Func().Call(rt.store, size)
if err != nil {
return 0, nil, err
}
return result.(int32), rt.newMemory(), nil
}
func putUint32Le(buf []byte, vmAddr int32, val uint32) error {
if int32(len(buf)) < vmAddr+4 {
return errors.New("overflow")
}
binary.LittleEndian.PutUint32(buf[vmAddr:], val)
return nil
}
func (rt *Runtime) Call(ctx context.Context, name string, args ...interface{}) (interface{}, error) {
ctx, l := logr.Start(ctx, "modules.vm.wasmtime.Runtime.Call", "func", name)
defer l.End()
if rt.module == nil {
return nil, ErrNotLinked
}
if rt.instance == nil {
return nil, ErrNotInstantiated
}
fn := rt.instance.GetFunc(rt.store, name)
if fn == nil {
return nil, ErrFuncNotImported
}
return fn.Call(rt.store, args...)
}
func (rt *Runtime) Read(addr, size int32) ([]byte, error) {
if rt.module == nil {
return nil, ErrNotLinked
}
if rt.instance == nil {
return nil, ErrNotInstantiated
}
mem := rt.newMemory()
if addr > int32(len(mem)) || addr+size > int32(len(mem)) {
return nil, errors.New("overflow")
}
buf := make([]byte, size)
if copied := copy(buf, mem[addr:addr+size]); int32(copied) != size {
return nil, errors.New("overflow")
}
return buf, nil
}
func (rt *Runtime) Copy(hostData []byte, vmAddrPtr, vmSizePtr int32) error {
if rt.module == nil {
return ErrNotLinked
}
if rt.instance == nil {
return ErrNotInstantiated
}
size := len(hostData)
addr, mem, err := rt.alloc(int32(size))
if err != nil {
return err
}
if copied := copy(mem[addr:], hostData); copied != size {
return errors.New("fail to copy data")
}
if err = putUint32Le(mem, vmAddrPtr, uint32(addr)); err != nil {
return err
}
return putUint32Le(mem, vmSizePtr, uint32(size))
}