nfv/guest-comm/host-guest-comm-2.0/host_guest_msg.c

125 lines
3.9 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.
*/
/**
*/
#define _GNU_SOURCE /* for memmem() */
#include <stddef.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <poll.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/select.h>
#include <sys/un.h>
#include <sys/socket.h>
#include <json-c/json.h>
#include "host_guest_msg_type.h"
/*
Multiple messages from the host can be bundled together into a single "read"
so we need to check message boundaries and handle breaking the message apart.
Assume a valid message does not contain newline '\n', and newline is added to
the beginning and end of each message by the sender to delimit the boundaries.
*/
void parser(void *buf, ssize_t len, int fd, json_tokener* tok, int newline_found)
{
json_object *jobj = json_tokener_parse_ex(tok, buf, len);
enum json_tokener_error jerr = json_tokener_get_error(tok);
if (jerr == json_tokener_success) {
process_msg(jobj, fd);
json_object_put(jobj);
return;
}
else if (jerr == json_tokener_continue) {
// partial JSON is parsed , continue to read from socket.
if (newline_found) {
// if newline was found in the middle of the buffer, the message
// should be completed at this point. Throw out incomplete message
// by resetting tokener.
json_tokener_reset(tok);
}
}
else
{
// parsing error
json_tokener_reset(tok);
}
}
void handle_virtio_serial_msg(void *buf, ssize_t len, int fd, json_tokener* tok)
{
void *newline;
ssize_t len_head;
next:
if (len == 0)
return;
// search for newline as delimiter
newline = memchr(buf, '\n', len);
if (newline) {
// split buffer to head and tail at the location of newline.
// feed the head to the parser and recursively process the tail.
len_head = newline-buf;
// parse head
if (len_head > 0)
parser(buf, len_head, fd, tok, 1);
// start of the tail: skip newline
buf += len_head+1;
// length of the tail: deduct 1 for the newline character
len -= len_head+1;
// continue to process the tail.
goto next;
}
else {
parser(buf, len, fd, tok, 0);
}
}