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