Add Go bindings

bindings/go/evmc/evmc.go

@@ -0,0 +1,273 @@
+// EVMC: Ethereum Client-VM Connector API.
+// Copyright 2018 Pawel Bylica.
+// Licensed under the MIT License. See the LICENSE file.
+
+package evmc
+
+/*
+#cgo CFLAGS:  -I${SRCDIR}/.. -Wall -Wextra
+#cgo LDFLAGS: -ldl
+
+#include <evmc/evmc.h>
+#include <evmc/helpers.h>
+#include <evmc/loader.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+static inline int set_option(struct evmc_instance* instance, char* name, char* value)
+{
+	int ret = evmc_set_option(instance, name, value);
+	free(name);
+	free(value);
+	return ret;
+}
+
+struct extended_context
+{
+	struct evmc_context context;
+	int64_t index;
+};
+
+extern const struct evmc_context_fn_table evmc_go_fn_table;
+
+static struct evmc_result execute_wrapper(struct evmc_instance* instance, int64_t context_index, enum evmc_revision rev,
+	const struct evmc_address* destination, const struct evmc_address* sender, const struct evmc_uint256be* value,
+	const uint8_t* input_data, size_t input_size, const struct evmc_uint256be* code_hash, int64_t gas,
+	int32_t depth, enum evmc_call_kind kind, uint32_t flags, const uint8_t* code, size_t code_size)
+{
+	struct evmc_uint256be create2_salt = {};
+	struct evmc_message msg = {
+		*destination,
+		*sender,
+		*value,
+		input_data,
+		input_size,
+		*code_hash,
+		create2_salt,
+		gas,
+		depth,
+		kind,
+		flags,
+	};
+
+	struct extended_context ctx = {{&evmc_go_fn_table}, context_index};
+	return instance->execute(instance, &ctx.context, rev, &msg, code, code_size);
+}
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"unsafe"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+// Static asserts.
+const (
+	_ = uint(common.HashLength - C.sizeof_struct_evmc_uint256be) // The size of evmc_uint256be equals the size of Hash.
+	_ = uint(C.sizeof_struct_evmc_uint256be - common.HashLength)
+	_ = uint(common.AddressLength - C.sizeof_struct_evmc_address) // The size of evmc_address equals the size of Address.
+	_ = uint(C.sizeof_struct_evmc_address - common.AddressLength)
+)
+
+type Error int32
+
+func (err Error) IsInternalError() bool {
+	return err < 0
+}
+
+func (err Error) Error() string {
+	code := C.enum_evmc_status_code(err)
+
+	switch code {
+	case C.EVMC_FAILURE:
+		return "evmc: failure"
+	case C.EVMC_REVERT:
+		return "evmc: revert"
+	case C.EVMC_OUT_OF_GAS:
+		return "evmc: out of gas"
+	case C.EVMC_INVALID_INSTRUCTION:
+		return "evmc: invalid instruction"
+	case C.EVMC_UNDEFINED_INSTRUCTION:
+		return "evmc: undefined instruction"
+	case C.EVMC_STACK_OVERFLOW:
+		return "evmc: stack overflow"
+	case C.EVMC_STACK_UNDERFLOW:
+		return "evmc: stack underflow"
+	case C.EVMC_BAD_JUMP_DESTINATION:
+		return "evmc: bad jump destination"
+	case C.EVMC_INVALID_MEMORY_ACCESS:
+		return "evmc: invalid memory access"
+	case C.EVMC_CALL_DEPTH_EXCEEDED:
+		return "evmc: call depth exceeded"
+	case C.EVMC_STATIC_MODE_VIOLATION:
+		return "evmc: static mode violation"
+	case C.EVMC_PRECOMPILE_FAILURE:
+		return "evmc: precompile failure"
+	case C.EVMC_CONTRACT_VALIDATION_FAILURE:
+		return "evmc: contract validation failure"
+	case C.EVMC_INTERNAL_ERROR:
+		return "evmc: internal error"
+	case C.EVMC_REJECTED:
+		return "evmc: rejected"
+	}
+
+	if code < 0 {
+		return fmt.Sprintf("evmc: unknown internal error (%d)", int32(code))
+	}
+
+	panic(fmt.Sprintf("evmc: unknown status code %d", int32(code)))
+}
+
+const (
+	Failure = Error(C.EVMC_FAILURE)
+	Revert  = Error(C.EVMC_REVERT)
+)
+
+type Revision int32
+
+const (
+	Frontier         Revision = C.EVMC_FRONTIER
+	Homestead        Revision = C.EVMC_HOMESTEAD
+	TangerineWhistle Revision = C.EVMC_TANGERINE_WHISTLE
+	SpuriousDragon   Revision = C.EVMC_SPURIOUS_DRAGON
+	Byzantium        Revision = C.EVMC_BYZANTIUM
+	Constantinople   Revision = C.EVMC_CONSTANTINOPLE
+)
+
+type Instance struct {
+	handle *C.struct_evmc_instance
+}
+
+func Load(filename string) (instance *Instance, err error) {
+	cfilename := C.CString(filename)
+	var loaderErr C.enum_evmc_loader_error_code
+	handle := C.evmc_load_and_create(cfilename, &loaderErr)
+	C.free(unsafe.Pointer(cfilename))
+	switch loaderErr {
+	case C.EVMC_LOADER_SUCCESS:
+		instance = &Instance{handle}
+	case C.EVMC_LOADER_CANNOT_OPEN:
+		err = fmt.Errorf("evmc loader: cannot open %s", filename)
+	case C.EVMC_LOADER_SYMBOL_NOT_FOUND:
+		err = fmt.Errorf("evmc loader: the EVMC create function not found in %s", filename)
+	case C.EVMC_LOADER_INVALID_ARGUMENT:
+		panic("evmc loader: filename argument is invalid")
+	case C.EVMC_LOADER_INSTANCE_CREATION_FAILURE:
+		err = errors.New("evmc loader: VM instance creation failure")
+	case C.EVMC_LOADER_ABI_VERSION_MISMATCH:
+		err = errors.New("evmc loader: ABI version mismatch")
+	default:
+		panic(fmt.Sprintf("evmc loader: unexpected error (%d)", int(loaderErr)))
+	}
+	return instance, err
+}
+
+func (instance *Instance) Destroy() {
+	C.evmc_destroy(instance.handle)
+}
+
+func (instance *Instance) Name() string {
+	return C.GoString(instance.handle.name)
+}
+
+func (instance *Instance) Version() string {
+	return C.GoString(instance.handle.version)
+}
+
+func (instance *Instance) SetOption(name string, value string) (err error) {
+
+	r := C.set_option(instance.handle, C.CString(name), C.CString(value))
+	if r != 1 {
+		err = fmt.Errorf("evmc: option '%s' not accepted", name)
+	}
+	return err
+}
+
+func (instance *Instance) Execute(ctx HostContext, rev Revision,
+	destination common.Address, sender common.Address, value common.Hash, input []byte, codeHash common.Hash, gas int64,
+	depth int, kind CallKind, static bool, code []byte) (output []byte, gasLeft int64, err error) {
+
+	flags := C.uint32_t(0)
+	if static {
+		flags |= C.EVMC_STATIC
+	}
+
+	ctxId := addHostContext(ctx)
+	// FIXME: Clarify passing by pointer vs passing by value.
+	evmcDestination := evmcAddress(destination)
+	evmcSender := evmcAddress(sender)
+	evmcValue := evmcUint256be(value)
+	evmcCodeHash := evmcUint256be(codeHash)
+	result := C.execute_wrapper(instance.handle, C.int64_t(ctxId), uint32(rev), &evmcDestination, &evmcSender, &evmcValue,
+		bytesPtr(input), C.size_t(len(input)), &evmcCodeHash, C.int64_t(gas), C.int32_t(depth), C.enum_evmc_call_kind(kind),
+		flags, bytesPtr(code), C.size_t(len(code)))
+	removeHostContext(ctxId)
+
+	output = C.GoBytes(unsafe.Pointer(result.output_data), C.int(result.output_size))
+	gasLeft = int64(result.gas_left)
+	if result.status_code != C.EVMC_SUCCESS {
+		err = Error(result.status_code)
+	}
+
+	if result.release != nil {
+		C.evmc_release_result(&result)
+	}
+
+	return output, gasLeft, err
+}
+
+var (
+	hostContextCounter int
+	hostContextMap     = map[int]HostContext{}
+	hostContextMapMu   sync.Mutex
+)
+
+func addHostContext(ctx HostContext) int {
+	hostContextMapMu.Lock()
+	id := hostContextCounter
+	hostContextCounter++
+	hostContextMap[id] = ctx
+	hostContextMapMu.Unlock()
+	return id
+}
+
+func removeHostContext(id int) {
+	hostContextMapMu.Lock()
+	delete(hostContextMap, id)
+	hostContextMapMu.Unlock()
+}
+
+func getHostContext(idx int) HostContext {
+	hostContextMapMu.Lock()
+	ctx := hostContextMap[idx]
+	hostContextMapMu.Unlock()
+	return ctx
+}
+
+func evmcUint256be(in common.Hash) C.struct_evmc_uint256be {
+	out := C.struct_evmc_uint256be{}
+	for i := 0; i < len(in); i++ {
+		out.bytes[i] = C.uint8_t(in[i])
+	}
+	return out
+}
+
+func evmcAddress(address common.Address) C.struct_evmc_address {
+	r := C.struct_evmc_address{}
+	for i := 0; i < len(address); i++ {
+		r.bytes[i] = C.uint8_t(address[i])
+	}
+	return r
+}
+
+func bytesPtr(bytes []byte) *C.uint8_t {
+	if len(bytes) == 0 {
+		return nil
+	}
+	return (*C.uint8_t)(unsafe.Pointer(&bytes[0]))
+}

bindings/go/evmc/evmc.h

@@ -0,0 +1 @@
+../../../include/evmc/evmc.h

bindings/go/evmc/evmc_test.go

@@ -0,0 +1,24 @@
+// EVMC: Ethereum Client-VM Connector API.
+// Copyright 2018 Pawel Bylica.
+// Licensed under the MIT License. See the LICENSE file.
+
+package evmc
+
+import (
+	"os"
+	"testing"
+)
+
+func TestLoad(t *testing.T) {
+	i, err := Load(os.Getenv("EVMC_PATH"))
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	defer i.Destroy()
+	if i.Name() != "interpreter" {
+		t.Fatal("name is not 'interpreter'")
+	}
+	if i.Version()[0] != '1' {
+		t.Fatalf("version is %s", i.Version())
+	}
+}

bindings/go/evmc/helpers.h

@@ -0,0 +1 @@
+../../../include/evmc/helpers.h

bindings/go/evmc/host.c

@@ -0,0 +1,29 @@
+/* EVMC: Ethereum Client-VM Connector API.
+ * Copyright 2018 Pawel Bylica.
+ * Licensed under the MIT License. See the LICENSE file.
+ */
+
+#include "_cgo_export.h"
+
+#include <stdlib.h>
+
+__attribute__((visibility("hidden"))) const struct evmc_context_fn_table evmc_go_fn_table = {
+    (evmc_account_exists_fn)accountExists,
+    (evmc_get_storage_fn)getStorage,
+    (evmc_set_storage_fn)setStorage,
+    (evmc_get_balance_fn)getBalance,
+    (evmc_get_code_size_fn)getCodeSize,
+    (evmc_get_code_hash_fn)getCodeHash,
+    (evmc_copy_code_fn)copyCode,
+    (evmc_selfdestruct_fn)selfdestruct,
+    (evmc_call_fn)call,
+    (evmc_get_tx_context_fn)getTxContext,
+    (evmc_get_block_hash_fn)getBlockHash,
+    (evmc_emit_log_fn)emitLog,
+};
+
+__attribute__((visibility("hidden"))) void evmc_go_free_result_output(
+    const struct evmc_result* result)
+{
+    free((void*)result->output_data);
+}