kvm tools: add kvm_ipc__send() and kvm_ipc__send_msg()

Current code write the sock manually. There is nothing constrains the format of
the written data is expect. Use kvm_ipc__send() and kvm_ipc__send_msg() for
such constraint.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

include/kvm/kvm-ipc.h

@@ -17,4 +17,7 @@ int kvm_ipc__register_handler(u32 type, void (*cb)(int fd, u32 type, u32 len, u8
 int kvm_ipc__start(int sock);
 int kvm_ipc__stop(void);
 
+int kvm_ipc__send(int fd, u32 type);
+int kvm_ipc__send_msg(int fd, u32 type, u32 len, u8 *msg);
+
 #endif

kvm-ipc.c

@@ -33,6 +33,29 @@ int kvm_ipc__register_handler(u32 type, void (*cb)(int fd, u32 type, u32 len, u8
 	return 0;
 }
 
+int kvm_ipc__send(int fd, u32 type)
+{
+	struct kvm_ipc_head head = {.type = type, .len = 0,};
+
+	if (write_in_full(fd, &head, sizeof(head)) != sizeof(head))
+		return -1;
+
+	return 0;
+}
+
+int kvm_ipc__send_msg(int fd, u32 type, u32 len, u8 *msg)
+{
+	struct kvm_ipc_head head = {.type = type, .len = len,};
+
+	if (write_in_full(fd, &head, sizeof(head)) != sizeof(head))
+		return -1;
+
+	if (write_in_full(fd, msg, len) != len)
+		return -1;
+
+	return 0;
+}
+
 static int kvm_ipc__handle(int fd, u32 type, u32 len, u8 *data)
 {
 	void (*cb)(int fd, u32 type, u32 len, u8 *msg);