TrueCloudLab/neoneo-go
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contract/vm: only push NULL after call in dynamic contexts

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And determine the need for Null dynamically. For some reason the only dynamic
context is Contract.Call. CALLT is not dynamic and neither is a call from
native contract, go figure...
This commit is contained in:
Roman Khimov 2022-08-04 18:17:32 +03:00
parent 99e2681d3a
commit e8d2277fe5
3 changed files with 20 additions and 9 deletions
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20
pkg/core/interop/contract/call.go
View file

@ -14,6 +14,7 @@ import (
"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/util"
"github.com/nspcc-dev/neo-go/pkg/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
@ -67,11 +68,11 @@ func Call(ic *interop.Context) error {
return fmt.Errorf("method not found: %s/%d", method, len(args))
}
hasReturn := md.ReturnType != smartcontract.VoidType
return callInternal(ic, cs, method, fs, hasReturn, args, !hasReturn)
return callInternal(ic, cs, method, fs, hasReturn, args, true)
}
func callInternal(ic *interop.Context, cs *state.Contract, name string, f callflag.CallFlag,
hasReturn bool, args []stackitem.Item, pushNullOnUnloading bool) error {
hasReturn bool, args []stackitem.Item, isDynamic bool) error {
md := cs.Manifest.ABI.GetMethod(name, len(args))
if md.Safe {
f &^= (callflag.WriteStates | callflag.AllowNotify)
@ -83,12 +84,12 @@ func callInternal(ic *interop.Context, cs *state.Contract, name string, f callfl
}
}
}
return callExFromNative(ic, ic.VM.GetCurrentScriptHash(), cs, name, args, f, hasReturn, pushNullOnUnloading, false)
return callExFromNative(ic, ic.VM.GetCurrentScriptHash(), cs, name, args, f, hasReturn, isDynamic, false)
}
// callExFromNative calls a contract with flags using the provided calling hash.
func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contract,
name string, args []stackitem.Item, f callflag.CallFlag, hasReturn bool, pushNullOnUnloading bool, callFromNative bool) error {
name string, args []stackitem.Item, f callflag.CallFlag, hasReturn bool, isDynamic bool, callFromNative bool) error {
for _, nc := range ic.Natives {
if nc.Metadata().Name == nativenames.Policy {
var pch = nc.(policyChecker)
@ -123,7 +124,7 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra
if wrapped {
ic.DAO = ic.DAO.GetPrivate()
}
onUnload := func(commit bool) error {
onUnload := func(ctx *vm.Context, commit bool) error {
if wrapped {
if commit {
_, err := ic.DAO.Persist()
@ -135,8 +136,13 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra
}
ic.DAO = baseDAO
}
if pushNullOnUnloading && commit {
ic.VM.Context().Estack().PushItem(stackitem.Null{}) // Must use current context stack.
if isDynamic && commit {
eLen := ctx.Estack().Len()
if eLen == 0 && ctx.NumOfReturnVals() == 0 { // No return value and none expected.
ic.VM.Context().Estack().PushItem(stackitem.Null{}) // Must use current context stack.
} else if eLen > 1 { // 1 or -1 (all) retrun values expected, but only one can be returned.
return errors.New("multiple return values in a cross-contract call")
} // All other rvcount/stack length mismatches are checked by the VM.
}
if callFromNative && !commit {
return fmt.Errorf("unhandled exception")

7
pkg/vm/context.go
View file

@ -73,7 +73,7 @@ type Context struct {
}
// ContextUnloadCallback is a callback method used on context unloading from istack.
type ContextUnloadCallback func(commit bool) error
type ContextUnloadCallback func(ctx *Context, commit bool) error
var errNoInstParam = errors.New("failed to read instruction parameter")
@ -239,6 +239,11 @@ func (c *Context) GetNEF() *nef.File {
return c.sc.NEF
}
// NumOfReturnVals returns the number of return values expected from this context.
func (c *Context) NumOfReturnVals() int {
return c.retCount
}
// Value implements the stackitem.Item interface.
func (c *Context) Value() interface{} {
return c

2
pkg/vm/vm.go
View file

@ -1634,7 +1634,7 @@ func (v *VM) unloadContext(ctx *Context) {
ctx.sc.static.ClearRefs(&v.refs)
}
if ctx.sc.onUnload != nil {
err := ctx.sc.onUnload(v.uncaughtException == 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 {