core/vm: implement metropolis static call opcode

1 files changed, 16 insertions, 0 deletions

diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go
index 3faa98704..32d764b9f 100644
--- a/core/vm/interpreter.go
+++ b/core/vm/interpreter.go
@@ -69,6 +69,8 @@ func NewInterpreter(evm *EVM, cfg Config) *Interpreter {
 	// we'll set the default jump table.
 	if !cfg.JumpTable[STOP].valid {
 		switch {
+		case evm.ChainConfig().IsMetropolis(evm.BlockNumber):
+			cfg.JumpTable = metropolisInstructionSet
 		case evm.ChainConfig().IsHomestead(evm.BlockNumber):
 			cfg.JumpTable = homesteadInstructionSet
 		default:
@@ -85,6 +87,19 @@ func NewInterpreter(evm *EVM, cfg Config) *Interpreter {
 }
 
 func (in *Interpreter) enforceRestrictions(op OpCode, operation operation, stack *Stack) error {
+	if in.evm.chainRules.IsMetropolis {
+		if in.readonly {
+			// if the interpreter is operating in readonly mode, make sure no
+			// state-modifying operation is performed. The 4th stack item
+			// for a call operation is the value. Transfering value from one
+			// account to the others means the state is modified and should also
+			// return with an error.
+			if operation.writes ||
+				((op == CALL || op == CALLCODE) && stack.Back(3).BitLen() > 0) {
+				return errWriteProtection
+			}
+		}
+	}
 	return nil
 }
 
@@ -95,6 +110,7 @@ func (in *Interpreter) enforceRestrictions(op OpCode, operation operation, stack
 // considered a revert-and-consume-all-gas operation. No error specific checks
 // should be handled to reduce complexity and errors further down the in.
 func (in *Interpreter) Run(snapshot int, contract *Contract, input []byte) (ret []byte, err error) {
+	// Increment the call depth which is restricted to 1024
 	in.evm.depth++
 	defer func() { in.evm.depth-- }()