lib: add libxpc to implement functionality needed by xpc interfaces

lib/libxpc/include/xpc/msg.h

@@ -0,0 +1,53 @@
+#ifndef XPC_MSG_H_
+#define XPC_MSG_H_
+
+#include <mango/types.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <xpc/endpoint.h>
+
+#define XPC_MSG_MAGIC 0x5850434D
+
+typedef struct xpc_msg_header {
+	uint32_t hdr_magic;
+	uint32_t hdr_interface;
+	uint16_t hdr_func;
+	uint16_t hdr_status;
+} xpc_msg_header_t;
+
+typedef struct xpc_msg {
+	xpc_endpoint_t msg_sender;
+	xpc_msg_header_t msg_header;
+	size_t msg_handles_count;
+
+	kern_msg_handle_t msg_handles[KERN_MSG_MAX_HANDLES];
+} xpc_msg_t;
+
+extern void xpc_msg_header_init(
+	xpc_msg_header_t *msg,
+	unsigned long interface,
+	unsigned short func);
+extern bool xpc_msg_header_validate(const xpc_msg_header_t *msg);
+extern kern_status_t xpc_msg_recv(kern_handle_t channel, xpc_msg_t *out);
+extern kern_status_t xpc_msg_read(
+	const xpc_msg_t *msg,
+	size_t offset,
+	void *p,
+	size_t count);
+extern kern_status_t xpc_msg_write(
+	const xpc_msg_t *msg,
+	size_t offset,
+	const void *p,
+	size_t count);
+
+extern kern_status_t xpc_msg_reply(
+	const xpc_msg_t *msg,
+	kern_iovec_t *iov,
+	size_t iov_count,
+	kern_msg_handle_t *handles,
+	size_t handle_count);
+extern kern_status_t xpc_msg_reply_error(
+	const xpc_msg_t *msg,
+	unsigned short code);
+
+#endif