Tools: acrn-manager: add lib with IPC helpers

Add lib to help IPC between components, including SOS lifecycle service,
acrn manager and devicemodule.
Following helper functions are included:
  int mngr_open_un() - create a descripter for vm management IPC
  void mngr_close() - close descripter and release the resouces
  int mngr_add_handler() - add a handler for message specified by msg
  int mngr_send_msg() - send a message and wait for ack

Reviewed-by: Kaige Fu <kaige.fu@intel.com>
Reviewed-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Wang, Yu <yu1.wang@intel.com>
Sigbed-off-by: Yan Like <like.yan@intel.com>
Signed-off-by: Tao Yuhong <yuhong.tao@intel.com>

tools/acrn-manager/acrn_mngr.h

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C)2018 Intel Corporation
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef ACRN_MANAGER_H
+#define ACRN_MANAGER_H
+
+#include <stdlib.h>
+
+/* Basic message format */
+
+#define MNGR_MSG_MAGIC   0x67736d206d6d76	/* that is char[8] "vmm msg", on X86 */
+#define VMNAME_LEN	16
+
+struct mngr_msg {
+	unsigned long long magic;	/* Make sure you get a vmm_msg */
+	unsigned int msgid;
+	unsigned long timestamp;
+	size_t len;		/* vmm_msg + payload size */
+	char payload[0];
+};
+
+/* vmm_msg event types */
+enum msgid {
+	MSG_MIN = 0,
+	MSG_STR,		/* The message payload is a string, terminated with '\0' */
+	MSG_MAX,
+};
+
+/* helper functions */
+#define MNGR_SERVER	1	/* create a server fd, which you can add handlers onto it */
+#define MNGR_CLIENT	0	/* create a client, just send req and read ack */
+
+/**
+ * @brief create a descripter for vm management IPC
+ *
+ * @param name: refer to a sock file under /run/acrn/mngr/[name].[pid].socket
+ * @param flags: MNGR_SERVER to create a server, MNGR_CLIENT to create a client
+ *
+ * @return descripter ID (> 1024) on success, errno (< 0) on error.
+ */
+int mngr_open_un(const char *name, int flags);
+
+/**
+ * @brief close descripter and release the resouces
+ *
+ * @param desc: descripter to be closed
+ */
+void mngr_close(int desc);
+
+/**
+ * @brief add a handler for message specified by msg
+ *
+ * @param desc: descripter to register handler to
+ * @param id: id of message to handle
+ * @param cb: handler callback
+ * @param param: param for the callback
+ * @return 0 on success, errno on error
+ */
+int mngr_add_handler(int desc, unsigned id,
+		     void (*cb) (struct mngr_msg * msg, int client_fd,
+				 void *param), void *param);
+
+/**
+ * @brief send a message and wait for ack
+ *
+ * @param desc: descripter created using mngr_open_un
+ * @param req: pointer to message to send
+ * @param ack: pointer to ack struct, NULL if no ack required
+ * @param len: size in byte of the message to send
+ * @param timeout: time to wait for ack, zero to blocking waiting
+ * @return len of ack messsage (0 if ack is NULL) on succes, errno on error
+ */
+int mngr_send_msg(int desc, struct mngr_msg *req, struct mngr_msg *ack,
+		  size_t len, unsigned timeout);
+
+#endif				/* ACRN_MANAGER_H */