diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 51fb0b3fc1..accca82069 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -723,7 +723,7 @@ bool is_valid_nodename(const char *node)
 /* We expect one arg in the input: return NULL otherwise.
  * The payload must contain exactly one nul, at the end.
  */
-static const char *onearg(struct buffered_data *in)
+const char *onearg(struct buffered_data *in)
 {
 	if (!in->used || get_string(in, 0) != in->used)
 		return NULL;
@@ -771,9 +771,10 @@ bool check_event_node(const char *node)
 	return true;
 }
 
-static void send_directory(struct connection *conn, const char *name)
+static void send_directory(struct connection *conn, struct buffered_data *in)
 {
 	struct node *node;
+	const char *name = onearg(in);
 
 	name = canonicalize(conn, name);
 	node = get_node(conn, name, XS_PERM_READ);
@@ -785,9 +786,10 @@ static void send_directory(struct connection *conn, const char *name)
 	send_reply(conn, XS_DIRECTORY, node->children, node->childlen);
 }
 
-static void do_read(struct connection *conn, const char *name)
+static void do_read(struct connection *conn, struct buffered_data *in)
 {
 	struct node *node;
+	const char *name = onearg(in);
 
 	name = canonicalize(conn, name);
 	node = get_node(conn, name, XS_PERM_READ);
@@ -953,9 +955,10 @@ static void do_write(struct connection *conn, struct buffered_data *in)
 	send_ack(conn, XS_WRITE);
 }
 
-static void do_mkdir(struct connection *conn, const char *name)
+static void do_mkdir(struct connection *conn, struct buffered_data *in)
 {
 	struct node *node;
+	const char *name = onearg(in);
 
 	name = canonicalize(conn, name);
 	node = get_node(conn, name, XS_PERM_WRITE);
@@ -1070,9 +1073,10 @@ static void internal_rm(const char *name)
 }
 
 
-static void do_rm(struct connection *conn, const char *name)
+static void do_rm(struct connection *conn, struct buffered_data *in)
 {
 	struct node *node;
+	const char *name = onearg(in);
 
 	name = canonicalize(conn, name);
 	node = get_node(conn, name, XS_PERM_WRITE);
@@ -1104,9 +1108,10 @@ static void do_rm(struct connection *conn, const char *name)
 }
 
 
-static void do_get_perms(struct connection *conn, const char *name)
+static void do_get_perms(struct connection *conn, struct buffered_data *in)
 {
 	struct node *node;
+	const char *name = onearg(in);
 	char *strings;
 	unsigned int len;
 
@@ -1220,11 +1225,11 @@ static void process_message(struct connection *conn, struct buffered_data *in)
 
 	switch (in->hdr.msg.type) {
 	case XS_DIRECTORY:
-		send_directory(conn, onearg(in));
+		send_directory(conn, in);
 		break;
 
 	case XS_READ:
-		do_read(conn, onearg(in));
+		do_read(conn, in);
 		break;
 
 	case XS_WRITE:
@@ -1232,15 +1237,15 @@ static void process_message(struct connection *conn, struct buffered_data *in)
 		break;
 
 	case XS_MKDIR:
-		do_mkdir(conn, onearg(in));
+		do_mkdir(conn, in);
 		break;
 
 	case XS_RM:
-		do_rm(conn, onearg(in));
+		do_rm(conn, in);
 		break;
 
 	case XS_GET_PERMS:
-		do_get_perms(conn, onearg(in));
+		do_get_perms(conn, in);
 		break;
 
 	case XS_SET_PERMS:
@@ -1264,7 +1269,7 @@ static void process_message(struct connection *conn, struct buffered_data *in)
 		break;
 
 	case XS_TRANSACTION_END:
-		do_transaction_end(conn, onearg(in));
+		do_transaction_end(conn, in);
 		break;
 
 	case XS_INTRODUCE:
@@ -1272,19 +1277,19 @@ static void process_message(struct connection *conn, struct buffered_data *in)
 		break;
 
 	case XS_IS_DOMAIN_INTRODUCED:
-		do_is_domain_introduced(conn, onearg(in));
+		do_is_domain_introduced(conn, in);
 		break;
 
 	case XS_RELEASE:
-		do_release(conn, onearg(in));
+		do_release(conn, in);
 		break;
 
 	case XS_GET_DOMAIN_PATH:
-		do_get_domain_path(conn, onearg(in));
+		do_get_domain_path(conn, in);
 		break;
 
 	case XS_RESUME:
-		do_resume(conn, onearg(in));
+		do_resume(conn, in);
 		break;
 
 	case XS_SET_TARGET:
@@ -1292,7 +1297,7 @@ static void process_message(struct connection *conn, struct buffered_data *in)
 		break;
 
 	case XS_RESET_WATCHES:
-		do_reset_watches(conn);
+		do_reset_watches(conn, in);
 		break;
 
 	default:
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 3a497f758a..5dbf9c816f 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -122,6 +122,9 @@ struct node {
 	char *children;
 };
 
+/* Return the only argument in the input. */
+const char *onearg(struct buffered_data *in);
+
 /* Break input into vectors, return the number, fill in up to num of them. */
 unsigned int get_strings(struct buffered_data *data,
 			 char *vec[], unsigned int num);
diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index 47b4f03156..c66539a6ef 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -453,8 +453,9 @@ void do_set_target(struct connection *conn, struct buffered_data *in)
 }
 
 /* domid */
-void do_release(struct connection *conn, const char *domid_str)
+void do_release(struct connection *conn, struct buffered_data *in)
 {
+	const char *domid_str = onearg(in);
 	struct domain *domain;
 	unsigned int domid;
 
@@ -490,10 +491,11 @@ void do_release(struct connection *conn, const char *domid_str)
 	send_ack(conn, XS_RELEASE);
 }
 
-void do_resume(struct connection *conn, const char *domid_str)
+void do_resume(struct connection *conn, struct buffered_data *in)
 {
 	struct domain *domain;
 	unsigned int domid;
+	const char *domid_str = onearg(in);
 
 	if (!domid_str) {
 		send_error(conn, EINVAL);
@@ -527,9 +529,10 @@ void do_resume(struct connection *conn, const char *domid_str)
 	send_ack(conn, XS_RESUME);
 }
 
-void do_get_domain_path(struct connection *conn, const char *domid_str)
+void do_get_domain_path(struct connection *conn, struct buffered_data *in)
 {
 	char *path;
+	const char *domid_str = onearg(in);
 
 	if (!domid_str) {
 		send_error(conn, EINVAL);
@@ -543,10 +546,11 @@ void do_get_domain_path(struct connection *conn, const char *domid_str)
 	talloc_free(path);
 }
 
-void do_is_domain_introduced(struct connection *conn, const char *domid_str)
+void do_is_domain_introduced(struct connection *conn, struct buffered_data *in)
 {
 	int result;
 	unsigned int domid;
+	const char *domid_str = onearg(in);
 
 	if (!domid_str) {
 		send_error(conn, EINVAL);
@@ -563,7 +567,7 @@ void do_is_domain_introduced(struct connection *conn, const char *domid_str)
 }
 
 /* Allow guest to reset all watches */
-void do_reset_watches(struct connection *conn)
+void do_reset_watches(struct connection *conn, struct buffered_data *in)
 {
 	conn_delete_all_watches(conn);
 	conn_delete_all_transactions(conn);
diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
index 83488edd4b..2554423f00 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -25,22 +25,22 @@ void handle_event(void);
 void do_introduce(struct connection *conn, struct buffered_data *in);
 
 /* domid */
-void do_is_domain_introduced(struct connection *conn, const char *domid_str);
+void do_is_domain_introduced(struct connection *conn, struct buffered_data *in);
 
 /* domid */
-void do_release(struct connection *conn, const char *domid_str);
+void do_release(struct connection *conn, struct buffered_data *in);
 
 /* domid */
-void do_resume(struct connection *conn, const char *domid_str);
+void do_resume(struct connection *conn, struct buffered_data *in);
 
 /* domid, target */
 void do_set_target(struct connection *conn, struct buffered_data *in);
 
 /* domid */
-void do_get_domain_path(struct connection *conn, const char *domid_str);
+void do_get_domain_path(struct connection *conn, struct buffered_data *in);
 
 /* Allow guest to reset all watches */
-void do_reset_watches(struct connection *conn);
+void do_reset_watches(struct connection *conn, struct buffered_data *in);
 
 void domain_init(void);
 
diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index d0e4739980..3cde26e532 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -184,8 +184,9 @@ void do_transaction_start(struct connection *conn, struct buffered_data *in)
 	send_reply(conn, XS_TRANSACTION_START, id_str, strlen(id_str)+1);
 }
 
-void do_transaction_end(struct connection *conn, const char *arg)
+void do_transaction_end(struct connection *conn, struct buffered_data *in)
 {
+	const char *arg = onearg(in);
 	struct changed_node *i;
 	struct changed_domain *d;
 	struct transaction *trans;
diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h
index cfeeae1ae0..0c868ee504 100644
--- a/tools/xenstore/xenstored_transaction.h
+++ b/tools/xenstore/xenstored_transaction.h
@@ -22,7 +22,7 @@
 struct transaction;
 
 void do_transaction_start(struct connection *conn, struct buffered_data *node);
-void do_transaction_end(struct connection *conn, const char *arg);
+void do_transaction_end(struct connection *conn, struct buffered_data *in);
 
 struct transaction *transaction_lookup(struct connection *conn, uint32_t id);