nfv/guest-comm/host-guest-comm-2.0/host_guest_msg.h
Dean Troyer 85cd488bef StarlingX open source release updates
Signed-off-by: Dean Troyer <dtroyer@gmail.com>
2018-05-31 07:36:51 -07:00

97 lines
4.1 KiB
C

/*
* Copyright (c) 2013-2016, Wind River Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2) Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* 3) Neither the name of Wind River Systems nor the names of its contributors may be
* used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef HOSTGUEST_MSG_H
#define HOSTGUEST_MSG_H
/* This implements a library for generic guest-host messaging.
*
* This handles some of the boilerplate code that would be common to
* all applications using the generic guest/host communications. That way
* any changes can be made in a single place.
*
* This should be threadsafe as long as multiple threads don't try to
* simultaneously process incoming messages using the same gh_info_t pointer.
*
*/
#include <sys/un.h>
#include <json-c/json.h>
/* Function signature for the guest-host messaging callback function.
* source_addr is a null-terminated string representing the host source address.
* The message contents are entirely up to the sender of the message.
*/
typedef void (*hg_msg_handler_t)(const char *source_addr, const char *source_instance,
struct json_object *jobj_msg);
#define HG_ERRORSIZE 400
typedef struct {
int sock; // socket for talking to guest agent
struct sockaddr_un svaddr; // address of guest agent
int svaddrlen; // length of guest agent address
char errorbuf[HG_ERRORSIZE];
hg_msg_handler_t hg_msg_handler;
} hg_info_t;
/* Allocate socket, set up callbacks, etc. This must be called once before
* any other API calls. "addr" is a null-terminated string of 16 chars or less
* (including the null) that is unique within this guest. "info" is the address
* of a value-result pointer that will be updated during the call.
*
* On success returns a socket and "info" is updated to point to an allocated chunk of memory.
* On error will return -1. If it was unable to allocate memory then "info" will be
* NULL. If it was able to allocate memory but something else failed then "info" will
* be non-NULL and you can call hg_get_error() to get an error message.
*/
int hg_init(hg_msg_handler_t msg_handler, char *addr, hg_info_t **info);
/* This should be called when the socket becomes readable. This may result in
* callbacks being called. Returns 0 on success.
* A negative return value indicates an error of some kind.
*/
int hg_process_msg(hg_info_t *info);
/* Send a message to an address on the host.
* Returns 0 on success.
* A negative return value indicates an error of some kind.
* The message must be a null-terminated string without embedded newlines.
*/
int hg_send_msg(hg_info_t *info, const char *dest_addr, const char *dest_instance,
const char *msg);
/* Get error message from most recent library call that returned an error. */
char *hg_get_error(hg_info_t *info);
#endif