open62541/src/server/ua_services_attribute.c

#include "ua_server_internal.h"
#include "ua_types_generated.h"
#include "ua_services.h"
#include "ua_statuscodes.h"
#include "ua_nodestore.h"
#include "ua_util.h"

/******************/
/* Read Attribute */
/******************/

static size_t readNumber(UA_Byte *buf, UA_Int32 buflen, UA_UInt32 *number) {
    UA_UInt32 n = 0;
    size_t progress = 0;
    /* read numbers until the end or a non-number character appears */
    UA_Byte c;
    while((UA_Int32)progress < buflen) {
        c = buf[progress];
        if('0' > c || '9' < c)
            break;
        n = (n*10) + (c-'0');
        progress++;
    }
    *number = n;
    return progress;
}

static size_t readDimension(UA_Byte *buf, UA_Int32 buflen, struct UA_NumericRangeDimension *dim) {
    size_t progress = readNumber(buf, buflen, &dim->min);
    if(progress == 0)
        return 0;
    if(buflen <= (UA_Int32)progress || buf[progress] != ':') {
        dim->max = dim->min;
        return progress;
    }
    size_t progress2 = readNumber(&buf[progress+1], buflen - (progress + 1), &dim->max);
    if(progress2 == 0)
        return 0;
    return progress + progress2 + 1;
}

#ifndef UA_BUILD_UNIT_TESTS
static
#endif
UA_StatusCode parse_numericrange(const UA_String *str, UA_NumericRange *range) {
    UA_Int32 index = 0;
    size_t dimensionsMax = 0;
    struct UA_NumericRangeDimension *dimensions = NULL;
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    size_t pos = 0;
    do {
        /* alloc dimensions */
        if(index >= (UA_Int32)dimensionsMax) {
            struct UA_NumericRangeDimension *newds;
            newds = UA_realloc(dimensions, sizeof(struct UA_NumericRangeDimension) * (dimensionsMax + 2));
            if(!newds) {
                retval = UA_STATUSCODE_BADOUTOFMEMORY;
                break;
            }
            dimensions = newds;
            dimensionsMax = dimensionsMax + 2;
        }

        /* read the dimension */
        size_t progress = readDimension(&str->data[pos], str->length - pos, &dimensions[index]);
        if(progress == 0) {
            retval = UA_STATUSCODE_BADINDEXRANGEINVALID;
            break;
        }
        pos += progress;
        index++;

        /* loop into the next dimension */
        if(pos >= str->length)
            break;
    } while(str->data[pos] == ',' && pos++);

    if(retval == UA_STATUSCODE_GOOD && index > 0) {
        range->dimensions = dimensions;
        range->dimensionsSize = index;
    } else
        UA_free(dimensions);

    return retval;
}

#define CHECK_NODECLASS(CLASS)                                  \
    if(!(node->nodeClass & (CLASS))) {                          \
        retval = UA_STATUSCODE_BADATTRIBUTEIDINVALID;           \
        break;                                                  \
    }

static void handleServerTimestamps(UA_TimestampsToReturn timestamps, UA_DataValue* v) {
	if(v && (timestamps == UA_TIMESTAMPSTORETURN_SERVER || timestamps == UA_TIMESTAMPSTORETURN_BOTH)) {
		v->hasServerTimestamp = UA_TRUE;
		v->serverTimestamp = UA_DateTime_now();
	}
}

static void handleSourceTimestamps(UA_TimestampsToReturn timestamps, UA_DataValue* v) {
	if(timestamps == UA_TIMESTAMPSTORETURN_SOURCE || timestamps == UA_TIMESTAMPSTORETURN_BOTH) {
		v->hasSourceTimestamp = UA_TRUE;
		v->sourceTimestamp = UA_DateTime_now();
	}
}

/* force cast for zero-copy reading. ensure that the variant is never written into. */
static void forceVariantSetScalar(UA_Variant *v, const void *p, const UA_DataType *type) {
    UA_Variant_init(v);
    v->type = type;
    v->data = (void*)(uintptr_t)p;
    v->storageType = UA_VARIANT_DATA_NODELETE;
}

static UA_StatusCode getVariableNodeValue(const UA_VariableNode *vn, const UA_TimestampsToReturn timestamps,
                                          const UA_ReadValueId *id, UA_DataValue *v) {
    UA_NumericRange range;
    UA_NumericRange *rangeptr = NULL;
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    if(id->indexRange.length > 0) {
        retval = parse_numericrange(&id->indexRange, &range);
        if(retval != UA_STATUSCODE_GOOD)
            return retval;
        rangeptr = &range;
    }

    if(vn->valueSource == UA_VALUESOURCE_VARIANT) {
        if(vn->value.variant.callback.onRead)
            vn->value.variant.callback.onRead(vn->value.variant.callback.handle, vn->nodeId,
                                              &v->value, rangeptr);
        if(!rangeptr) {
            v->value = vn->value.variant.value;
            v->value.storageType = UA_VARIANT_DATA_NODELETE;
        } else
            retval = UA_Variant_copyRange(&vn->value.variant.value, &v->value, range);
        if(retval == UA_STATUSCODE_GOOD)
            handleSourceTimestamps(timestamps, v);
    } else {
        if(vn->value.dataSource.read == NULL) {
            retval = UA_STATUSCODE_BADINTERNALERROR;
        } else {
            UA_Boolean sourceTimeStamp = (timestamps == UA_TIMESTAMPSTORETURN_SOURCE ||
                                          timestamps == UA_TIMESTAMPSTORETURN_BOTH);
            retval = vn->value.dataSource.read(vn->value.dataSource.handle, vn->nodeId,
                                               sourceTimeStamp, rangeptr, v);
        }
    }

    if(rangeptr)
        UA_free(range.dimensions);
    return retval;
}

static UA_StatusCode getVariableNodeDataType(const UA_VariableNode *vn, UA_DataValue *v) {
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    if(vn->valueSource == UA_VALUESOURCE_VARIANT) {
        forceVariantSetScalar(&v->value, &vn->value.variant.value.type->typeId,
                              &UA_TYPES[UA_TYPES_NODEID]);
    } else {
        if(vn->value.dataSource.read == NULL)
            return UA_STATUSCODE_BADINTERNALERROR;
        /* Read from the datasource to see the data type */
        UA_DataValue val;
        UA_DataValue_init(&val);
        retval = vn->value.dataSource.read(vn->value.dataSource.handle, vn->nodeId, UA_FALSE, NULL, &val);
        if(retval != UA_STATUSCODE_GOOD)
            return retval;
        retval = UA_Variant_setScalarCopy(&v->value, &val.value.type->typeId, &UA_TYPES[UA_TYPES_NODEID]);
        UA_DataValue_deleteMembers(&val);
    }
    return retval;
}

static UA_StatusCode getVariableNodeArrayDimensions(const UA_VariableNode *vn, UA_DataValue *v) {
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    if(vn->valueSource == UA_VALUESOURCE_VARIANT) {
        UA_Variant_setArray(&v->value, vn->value.variant.value.arrayDimensions,
                            vn->value.variant.value.arrayDimensionsSize, &UA_TYPES[UA_TYPES_INT32]);
        v->value.storageType = UA_VARIANT_DATA_NODELETE;
    } else {
        if(vn->value.dataSource.read == NULL)
            return UA_STATUSCODE_BADINTERNALERROR;
        /* Read the datasource to see the array dimensions */
        UA_DataValue val;
        UA_DataValue_init(&val);
        retval = vn->value.dataSource.read(vn->value.dataSource.handle, vn->nodeId, UA_FALSE, NULL, &val);
        if(retval != UA_STATUSCODE_GOOD)
            return retval;
        retval = UA_Variant_setArrayCopy(&v->value, val.value.arrayDimensions,
                                         val.value.arrayDimensionsSize, &UA_TYPES[UA_TYPES_INT32]);
        UA_DataValue_deleteMembers(&val);
    }
    return retval;
}

static const UA_String binEncoding = {sizeof("DefaultBinary")-1, (UA_Byte*)"DefaultBinary"};
/* clang complains about unused variables */
// static const UA_String xmlEncoding = {sizeof("DefaultXml")-1, (UA_Byte*)"DefaultXml"};

/** Reads a single attribute from a node in the nodestore. */
void Service_Read_single(UA_Server *server, UA_Session *session, const UA_TimestampsToReturn timestamps,
                         const UA_ReadValueId *id, UA_DataValue *v) {
	if(id->dataEncoding.name.length > 0 && !UA_String_equal(&binEncoding, &id->dataEncoding.name)) {
           v->hasStatus = UA_TRUE;
           v->status = UA_STATUSCODE_BADDATAENCODINGINVALID;
           return;
	}

	//index range for a non-value
	if(id->indexRange.length > 0 && id->attributeId != UA_ATTRIBUTEID_VALUE){
		v->hasStatus = UA_TRUE;
		v->status = UA_STATUSCODE_BADINDEXRANGENODATA;
		return;
	}

    UA_Node const *node = UA_NodeStore_get(server->nodestore, &id->nodeId);
    if(!node) {
        v->hasStatus = UA_TRUE;
        v->status = UA_STATUSCODE_BADNODEIDUNKNOWN;
        return;
    }

    /* When setting the value fails in the switch, we get an error code and set hasValue to false */
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    v->hasValue = UA_TRUE;
    switch(id->attributeId) {
    case UA_ATTRIBUTEID_NODEID:
        forceVariantSetScalar(&v->value, &node->nodeId, &UA_TYPES[UA_TYPES_NODEID]);
        break;
    case UA_ATTRIBUTEID_NODECLASS:
        forceVariantSetScalar(&v->value, &node->nodeClass, &UA_TYPES[UA_TYPES_INT32]);
        break;
    case UA_ATTRIBUTEID_BROWSENAME:
        forceVariantSetScalar(&v->value, &node->browseName, &UA_TYPES[UA_TYPES_QUALIFIEDNAME]);
        break;
    case UA_ATTRIBUTEID_DISPLAYNAME:
        forceVariantSetScalar(&v->value, &node->displayName, &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
        break;
    case UA_ATTRIBUTEID_DESCRIPTION:
        forceVariantSetScalar(&v->value, &node->description, &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
        break;
    case UA_ATTRIBUTEID_WRITEMASK:
        forceVariantSetScalar(&v->value, &node->writeMask, &UA_TYPES[UA_TYPES_UINT32]);
        break;
    case UA_ATTRIBUTEID_USERWRITEMASK:
        forceVariantSetScalar(&v->value, &node->userWriteMask, &UA_TYPES[UA_TYPES_UINT32]);
        break;
    case UA_ATTRIBUTEID_ISABSTRACT:
        CHECK_NODECLASS(UA_NODECLASS_REFERENCETYPE | UA_NODECLASS_OBJECTTYPE |
                        UA_NODECLASS_VARIABLETYPE | UA_NODECLASS_DATATYPE);
        forceVariantSetScalar(&v->value, &((const UA_ReferenceTypeNode*)node)->isAbstract,
                              &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_SYMMETRIC:
        CHECK_NODECLASS(UA_NODECLASS_REFERENCETYPE);
        forceVariantSetScalar(&v->value, &((const UA_ReferenceTypeNode*)node)->symmetric,
                              &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_INVERSENAME:
        CHECK_NODECLASS(UA_NODECLASS_REFERENCETYPE);
        forceVariantSetScalar(&v->value, &((const UA_ReferenceTypeNode*)node)->inverseName,
                              &UA_TYPES[UA_TYPES_LOCALIZEDTEXT]);
        break;
    case UA_ATTRIBUTEID_CONTAINSNOLOOPS:
        CHECK_NODECLASS(UA_NODECLASS_VIEW);
        forceVariantSetScalar(&v->value, &((const UA_ViewNode*)node)->containsNoLoops,
                              &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_EVENTNOTIFIER:
        CHECK_NODECLASS(UA_NODECLASS_VIEW | UA_NODECLASS_OBJECT);
        forceVariantSetScalar(&v->value, &((const UA_ViewNode*)node)->eventNotifier,
                              &UA_TYPES[UA_TYPES_BYTE]);
        break;
    case UA_ATTRIBUTEID_VALUE:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        retval = getVariableNodeValue((const UA_VariableNode*)node, timestamps, id, v);
        break;
    case UA_ATTRIBUTEID_DATATYPE:
		CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        retval = getVariableNodeDataType((const UA_VariableNode*)node, v);
        break;
    case UA_ATTRIBUTEID_VALUERANK:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        forceVariantSetScalar(&v->value, &((const UA_VariableTypeNode*)node)->valueRank,
                              &UA_TYPES[UA_TYPES_INT32]);
        break;
    case UA_ATTRIBUTEID_ARRAYDIMENSIONS:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        retval = getVariableNodeArrayDimensions((const UA_VariableNode*)node, v);
        break;
    case UA_ATTRIBUTEID_ACCESSLEVEL:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        forceVariantSetScalar(&v->value, &((const UA_VariableNode*)node)->accessLevel,
                              &UA_TYPES[UA_TYPES_BYTE]);
        break;
    case UA_ATTRIBUTEID_USERACCESSLEVEL:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        forceVariantSetScalar(&v->value, &((const UA_VariableNode*)node)->userAccessLevel,
                              &UA_TYPES[UA_TYPES_BYTE]);
        break;
    case UA_ATTRIBUTEID_MINIMUMSAMPLINGINTERVAL:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        forceVariantSetScalar(&v->value, &((const UA_VariableNode*)node)->minimumSamplingInterval,
                              &UA_TYPES[UA_TYPES_DOUBLE]);
        break;
    case UA_ATTRIBUTEID_HISTORIZING:
        CHECK_NODECLASS(UA_NODECLASS_VARIABLE);
        forceVariantSetScalar(&v->value, &((const UA_VariableNode*)node)->historizing,
                              &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_EXECUTABLE:
        CHECK_NODECLASS(UA_NODECLASS_METHOD);
        forceVariantSetScalar(&v->value, &((const UA_MethodNode*)node)->executable,
                              &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    case UA_ATTRIBUTEID_USEREXECUTABLE:
        CHECK_NODECLASS(UA_NODECLASS_METHOD);
        forceVariantSetScalar(&v->value, &((const UA_MethodNode*)node)->userExecutable,
                              &UA_TYPES[UA_TYPES_BOOLEAN]);
        break;
    default:
        retval = UA_STATUSCODE_BADATTRIBUTEIDINVALID;
        break;
    }

    if(retval != UA_STATUSCODE_GOOD) {
        v->hasValue = UA_FALSE;
        v->hasStatus = UA_TRUE;
        v->status = retval;
    }

    // Todo: what if the timestamp from the datasource are already present?
    handleServerTimestamps(timestamps, v);
}

void Service_Read(UA_Server *server, UA_Session *session, const UA_ReadRequest *request,
                  UA_ReadResponse *response) {
    UA_LOG_DEBUG(server->config.logger, UA_LOGCATEGORY_SESSION,
                 "Processing ReadRequest for Session (ns=%i,i=%i)",
                 session->sessionId.namespaceIndex, session->sessionId.identifier.numeric);
    if(request->nodesToReadSize <= 0) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;
        return;
    }

    if(request->timestampsToReturn > 3){
    	response->responseHeader.serviceResult = UA_STATUSCODE_BADTIMESTAMPSTORETURNINVALID;
    	return;
    }

    size_t size = request->nodesToReadSize;
    response->results = UA_Array_new(size, &UA_TYPES[UA_TYPES_DATAVALUE]);
    if(!response->results) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;
        return;
    }

    response->resultsSize = size;
    if(request->maxAge < 0) {
    	response->responseHeader.serviceResult = UA_STATUSCODE_BADMAXAGEINVALID;
        return;
    }

#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    UA_Boolean isExternal[size];
    UA_UInt32 indices[size];
    memset(isExternal, UA_FALSE, sizeof(UA_Boolean) * size);
    for(size_t j = 0;j<server->externalNamespacesSize;j++) {
        size_t indexSize = 0;
        for(size_t i = 0;i < size;i++) {
            if(request->nodesToRead[i].nodeId.namespaceIndex != server->externalNamespaces[j].index)
                continue;
            isExternal[i] = UA_TRUE;
            indices[indexSize] = i;
            indexSize++;
        }
        if(indexSize == 0)
            continue;
        UA_ExternalNodeStore *ens = &server->externalNamespaces[j].externalNodeStore;
        ens->readNodes(ens->ensHandle, &request->requestHeader, request->nodesToRead,
                       indices, indexSize, response->results, UA_FALSE, response->diagnosticInfos);
    }
#endif

    for(size_t i = 0;i < size;i++) {
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
        if(!isExternal[i])
#endif
            Service_Read_single(server, session, request->timestampsToReturn,
                                &request->nodesToRead[i], &response->results[i]);
    }

#ifdef UA_ENABLE_NONSTANDARD_STATELESS
    /* Add an expiry header for caching */
    if(session==&anonymousSession){
		UA_ExtensionObject additionalHeader;
		UA_ExtensionObject_init(&additionalHeader);
		additionalHeader.typeId = UA_TYPES[UA_TYPES_VARIANT].typeId;
		additionalHeader.encoding = UA_EXTENSIONOBJECT_ENCODINGMASK_BODYISBYTESTRING;

		UA_Variant variant;
		UA_Variant_init(&variant);

		UA_DateTime* expireArray = NULL;
		expireArray = UA_Array_new(&UA_TYPES[UA_TYPES_DATETIME], request->nodesToReadSize);
		variant.data = expireArray;

		/*expires in 20 seconds*/
		for(UA_Int32 i = 0;i < response->resultsSize;i++) {
			expireArray[i] = UA_DateTime_now() + 20 * 100 * 1000 * 1000;
		}
		UA_Variant_setArray(&variant, expireArray, request->nodesToReadSize, &UA_TYPES[UA_TYPES_DATETIME]);

		size_t offset = 0;
		UA_ByteString str;
        UA_ByteString_newMembers(&str, 65536);
		UA_Variant_encodeBinary(&variant, &str, &offset);

        UA_Array_delete(expireArray, &UA_TYPES[UA_TYPES_DATETIME], request->nodesToReadSize);

		additionalHeader.body = str;
		additionalHeader.body.length = offset;
		response->responseHeader.additionalHeader = additionalHeader;
    }
#endif
}

/*******************/
/* Write Attribute */
/*******************/

UA_StatusCode UA_Server_editNode(UA_Server *server, UA_Session *session, const UA_NodeId *nodeId,
                                 UA_EditNodeCallback callback, const void *data) {
    UA_StatusCode retval;
    do {
        UA_MT_CONST UA_Node *node = UA_NodeStore_get(server->nodestore, nodeId);
        if(!node)
            return UA_STATUSCODE_BADNODEIDUNKNOWN;
#ifndef UA_ENABLE_MULTITHREADING
        retval = callback(server, session, node, data);
        return retval;
#else
        UA_Node *copy = UA_Node_copyAnyNodeClass(node);
        if(!copy)
            return UA_STATUSCODE_BADOUTOFMEMORY;
        retval = callback(server, session, copy, data);
        if(retval != UA_STATUSCODE_GOOD) {
            UA_Node_deleteAnyNodeClass(copy);
            return retval;
        }
        retval = UA_NodeStore_replace(server->nodestore, node, copy, NULL);
        if(retval != UA_STATUSCODE_GOOD)
            UA_Node_deleteAnyNodeClass(copy);
#endif
    } while(retval != UA_STATUSCODE_GOOD);
    return UA_STATUSCODE_GOOD;
}

#define CHECK_DATATYPE(EXP_DT)                                          \
    if(!wvalue->value.hasValue ||                                       \
       &UA_TYPES[UA_TYPES_##EXP_DT] != wvalue->value.value.type ||      \
       !UA_Variant_isScalar(&wvalue->value.value)) {                    \
        retval = UA_STATUSCODE_BADTYPEMISMATCH;                         \
        break;                                                          \
    }

#define CHECK_NODECLASS_WRITE(CLASS)                                    \
    if((node->nodeClass & (CLASS)) == 0) {                              \
        retval = UA_STATUSCODE_BADNODECLASSINVALID;                     \
        break;                                                          \
    }

static UA_StatusCode
Service_Write_single_ValueDataSource(UA_Server *server, UA_Session *session, const UA_VariableNode *node,
                                     const UA_WriteValue *wvalue) {
    UA_assert(wvalue->attributeId == UA_ATTRIBUTEID_VALUE);
    UA_assert(node->nodeClass == UA_NODECLASS_VARIABLE || node->nodeClass == UA_NODECLASS_VARIABLETYPE);
    UA_assert(node->valueSource == UA_VALUESOURCE_DATASOURCE);

    if(node->value.dataSource.write == NULL)
        return UA_STATUSCODE_BADWRITENOTSUPPORTED;

    UA_StatusCode retval;
    if(wvalue->indexRange.length <= 0) {
        retval = node->value.dataSource.write(node->value.dataSource.handle, node->nodeId,
                                              &wvalue->value.value, NULL);
    } else {
        UA_NumericRange range;
        retval = parse_numericrange(&wvalue->indexRange, &range);
        if(retval != UA_STATUSCODE_GOOD)
            return retval;
        retval = node->value.dataSource.write(node->value.dataSource.handle, node->nodeId,
                                              &wvalue->value.value, &range);
        UA_free(range.dimensions);
    }
    return retval;
}

enum type_equivalence {
    TYPE_EQUIVALENCE_NONE,
    TYPE_EQUIVALENCE_ENUM,
    TYPE_EQUIVALENCE_OPAQUE
};

static enum type_equivalence typeEquivalence(const UA_DataType *type) {
    if(type->membersSize != 1 || !type->members[0].namespaceZero)
        return TYPE_EQUIVALENCE_NONE;
    if(type->members[0].memberTypeIndex == UA_TYPES_INT32)
        return TYPE_EQUIVALENCE_ENUM;
    if(type->members[0].memberTypeIndex == UA_TYPES_BYTE && type->members[0].isArray)
        return TYPE_EQUIVALENCE_OPAQUE;
    return TYPE_EQUIVALENCE_NONE;
}

/* In the multithreaded case, node is a copy */
static UA_StatusCode
CopyValueIntoNode(UA_VariableNode *node, const UA_WriteValue *wvalue) {
    UA_assert(wvalue->attributeId == UA_ATTRIBUTEID_VALUE);
    UA_assert(node->nodeClass == UA_NODECLASS_VARIABLE || node->nodeClass == UA_NODECLASS_VARIABLETYPE);
    UA_assert(node->valueSource == UA_VALUESOURCE_VARIANT);

    /* Parse the range */
    UA_NumericRange range;
    UA_NumericRange *rangeptr = NULL;
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    if(wvalue->indexRange.length > 0) {
        retval = parse_numericrange(&wvalue->indexRange, &range);
        if(retval != UA_STATUSCODE_GOOD)
            return retval;
        rangeptr = &range;
    }

    /* The nodeid on the wire may be != the nodeid in the node: opaque types, enums and bytestrings.
       nodeV contains the correct type definition. */
    const UA_Variant *newV = &wvalue->value.value;
    UA_Variant *oldV = &node->value.variant.value;
    UA_Variant cast_v;
    if (oldV->type != NULL) { // Don't run NodeId_equal on a NULL pointer (happens if the variable never held a variant)
      if(!UA_NodeId_equal(&oldV->type->typeId, &newV->type->typeId)) {
          cast_v = wvalue->value.value;
          newV = &cast_v;
          enum type_equivalence te1 = typeEquivalence(oldV->type);
          enum type_equivalence te2 = typeEquivalence(newV->type);
          if(te1 != TYPE_EQUIVALENCE_NONE && te1 == te2) {
              /* An enum was sent as an int32, or an opaque type as a bytestring. This is
                detected with the typeIndex indicated the "true" datatype. */
              cast_v.type = oldV->type;
          } else if(oldV->type == &UA_TYPES[UA_TYPES_BYTE] && !UA_Variant_isScalar(oldV) &&
                    newV->type == &UA_TYPES[UA_TYPES_BYTESTRING] && UA_Variant_isScalar(newV)) {
              /* a string is written to a byte array */
              UA_ByteString *str = (UA_ByteString*) newV->data;
              cast_v.arrayLength = str->length;
              cast_v.data = str->data;
              cast_v.type = &UA_TYPES[UA_TYPES_BYTE];
          } else {
              if(rangeptr)
                  UA_free(range.dimensions);
              return UA_STATUSCODE_BADTYPEMISMATCH;
          }
      }
    }
    
    if(!rangeptr) {
        UA_Variant_deleteMembers(&node->value.variant.value);
        UA_Variant_copy(newV, &node->value.variant.value);
    } else
        retval = UA_Variant_setRangeCopy(&node->value.variant.value, newV->data, newV->arrayLength, range);
    if(node->value.variant.callback.onWrite)
        node->value.variant.callback.onWrite(node->value.variant.callback.handle, node->nodeId,
                                             &node->value.variant.value, rangeptr);
    if(rangeptr)
        UA_free(range.dimensions);
    return retval;
}

static UA_StatusCode
CopyAttributeIntoNode(UA_Server *server, UA_Session *session,
                      UA_Node *node, const UA_WriteValue *wvalue) {
    if(!wvalue->value.hasValue)
        return UA_STATUSCODE_BADNODATA;

    void *value = wvalue->value.value.data;
    void *target = NULL;
    const UA_DataType *type = NULL;

    UA_StatusCode retval = UA_STATUSCODE_GOOD;
	switch(wvalue->attributeId) {
    case UA_ATTRIBUTEID_NODEID:
    case UA_ATTRIBUTEID_NODECLASS:
    case UA_ATTRIBUTEID_DATATYPE:
		retval = UA_STATUSCODE_BADWRITENOTSUPPORTED;
		break;
	case UA_ATTRIBUTEID_BROWSENAME:
		CHECK_DATATYPE(QUALIFIEDNAME);
        target = &node->browseName;
        type = &UA_TYPES[UA_TYPES_QUALIFIEDNAME];
		break;
	case UA_ATTRIBUTEID_DISPLAYNAME:
		CHECK_DATATYPE(LOCALIZEDTEXT);
        target = &node->displayName;
        type = &UA_TYPES[UA_TYPES_LOCALIZEDTEXT];
		break;
	case UA_ATTRIBUTEID_DESCRIPTION:
		CHECK_DATATYPE(LOCALIZEDTEXT);
        target = &node->description;
        type = &UA_TYPES[UA_TYPES_LOCALIZEDTEXT];
		break;
	case UA_ATTRIBUTEID_WRITEMASK:
		CHECK_DATATYPE(UINT32);
		node->writeMask = *(UA_UInt32*)value;
		break;
	case UA_ATTRIBUTEID_USERWRITEMASK:
		CHECK_DATATYPE(UINT32);
		node->userWriteMask = *(UA_UInt32*)value;
		break;    
	case UA_ATTRIBUTEID_ISABSTRACT:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_OBJECTTYPE | UA_NODECLASS_REFERENCETYPE |
                              UA_NODECLASS_VARIABLETYPE | UA_NODECLASS_DATATYPE);
		CHECK_DATATYPE(BOOLEAN);
		((UA_ObjectTypeNode*)node)->isAbstract = *(UA_Boolean*)value;
		break;
	case UA_ATTRIBUTEID_SYMMETRIC:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_REFERENCETYPE);
		CHECK_DATATYPE(BOOLEAN);
		((UA_ReferenceTypeNode*)node)->symmetric = *(UA_Boolean*)value;
		break;
	case UA_ATTRIBUTEID_INVERSENAME:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_REFERENCETYPE);
		CHECK_DATATYPE(LOCALIZEDTEXT);
        target = &((UA_ReferenceTypeNode*)node)->inverseName;
        type = &UA_TYPES[UA_TYPES_LOCALIZEDTEXT];
		break;
	case UA_ATTRIBUTEID_CONTAINSNOLOOPS:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VIEW);
		CHECK_DATATYPE(BOOLEAN);
        ((UA_ViewNode*)node)->containsNoLoops = *(UA_Boolean*)value;
		break;
	case UA_ATTRIBUTEID_EVENTNOTIFIER:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VIEW | UA_NODECLASS_OBJECT);
		CHECK_DATATYPE(BYTE);
        ((UA_ViewNode*)node)->eventNotifier = *(UA_Byte*)value;
		break;
	case UA_ATTRIBUTEID_VALUE:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE | UA_NODECLASS_VARIABLETYPE);
        if(((const UA_VariableNode*)node)->valueSource == UA_VALUESOURCE_VARIANT)
            retval = CopyValueIntoNode((UA_VariableNode*)node, wvalue);
        else
            retval = Service_Write_single_ValueDataSource(server, session, (const UA_VariableNode*)node, wvalue);
		break;
	case UA_ATTRIBUTEID_ACCESSLEVEL:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
		CHECK_DATATYPE(BYTE);
		((UA_VariableNode*)node)->accessLevel = *(UA_Byte*)value;
		break;
	case UA_ATTRIBUTEID_USERACCESSLEVEL:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
		CHECK_DATATYPE(BYTE);
		((UA_VariableNode*)node)->userAccessLevel = *(UA_Byte*)value;
		break;
	case UA_ATTRIBUTEID_MINIMUMSAMPLINGINTERVAL:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
		CHECK_DATATYPE(DOUBLE);
		((UA_VariableNode*)node)->minimumSamplingInterval = *(UA_Double*)value;
		break;
	case UA_ATTRIBUTEID_HISTORIZING:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_VARIABLE);
		CHECK_DATATYPE(BOOLEAN);
		((UA_VariableNode*)node)->historizing = *(UA_Boolean*)value;
		break;
	case UA_ATTRIBUTEID_EXECUTABLE:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_METHOD);
		CHECK_DATATYPE(BOOLEAN);
		((UA_MethodNode*)node)->executable = *(UA_Boolean*)value;
		break;
	case UA_ATTRIBUTEID_USEREXECUTABLE:
		CHECK_NODECLASS_WRITE(UA_NODECLASS_METHOD);
		CHECK_DATATYPE(BOOLEAN);
		((UA_MethodNode*)node)->userExecutable = *(UA_Boolean*)value;
		break;
	default:
		retval = UA_STATUSCODE_BADATTRIBUTEIDINVALID;
		break;
	}
    if(type) {
        UA_deleteMembers(target, type);
        retval = UA_copy(value, target, type);
    }
    return retval;
}

UA_StatusCode Service_Write_single(UA_Server *server, UA_Session *session, const UA_WriteValue *wvalue) {
    return UA_Server_editNode(server, session, &wvalue->nodeId, (UA_EditNodeCallback)CopyAttributeIntoNode, wvalue);
}

void Service_Write(UA_Server *server, UA_Session *session, const UA_WriteRequest *request,
                   UA_WriteResponse *response) {
    UA_assert(server != NULL && session != NULL && request != NULL && response != NULL);
    UA_LOG_DEBUG(server->config.logger, UA_LOGCATEGORY_SESSION,
                 "Processing WriteRequest for Session (ns=%i,i=%i)",
                 session->sessionId.namespaceIndex, session->sessionId.identifier.numeric);

    if(request->nodesToWriteSize <= 0) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTHINGTODO;
        return;
    }

    response->results = UA_Array_new(request->nodesToWriteSize, &UA_TYPES[UA_TYPES_STATUSCODE]);
    if(!response->results) {
        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;
        return;
    }

#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
    UA_Boolean isExternal[request->nodesToWriteSize];
    UA_UInt32 indices[request->nodesToWriteSize];
    memset(isExternal, UA_FALSE, sizeof(UA_Boolean)*request->nodesToWriteSize);
    for(size_t j = 0; j < server->externalNamespacesSize; j++) {
        UA_UInt32 indexSize = 0;
        for(UA_Int32 i = 0; i < request->nodesToWriteSize; i++) {
            if(request->nodesToWrite[i].nodeId.namespaceIndex !=
               server->externalNamespaces[j].index)
                continue;
            isExternal[i] = UA_TRUE;
            indices[indexSize] = i;
            indexSize++;
        }
        if(indexSize == 0)
            continue;
        UA_ExternalNodeStore *ens = &server->externalNamespaces[j].externalNodeStore;
        ens->writeNodes(ens->ensHandle, &request->requestHeader, request->nodesToWrite,
                        indices, indexSize, response->results, response->diagnosticInfos);
    }
#endif
    
    response->resultsSize = request->nodesToWriteSize;
    for(size_t i = 0;i < request->nodesToWriteSize;i++) {
#ifdef UA_ENABLE_EXTERNAL_NAMESPACES
        if(!isExternal[i])
#endif
		  response->results[i] = Service_Write_single(server, session, &request->nodesToWrite[i]);
    }
}