/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1990-2011 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* syscall message server side receipt
*/
#include "msglib.h"
#include <cs.h>
/*
* read a message from fd into buf,siz
* handles record boundaries on fd
* siz must be > MSG_SIZE_SIZE
*/
ssize_t
msgread(int fd, char* buf, size_t siz)
{
register ssize_t n;
register int o;
if ((n = cspeek(&cs, fd, buf, MSG_SIZE_SIZE)) >= 0) o = 0;
else
{
n = csread(&cs, fd, buf, MSG_SIZE_SIZE, CS_EXACT);
o = MSG_SIZE_SIZE;
}
if (n != MSG_SIZE_SIZE) return n ? -1 : 0;
n = msggetsize(buf);
if (n <= MSG_SIZE_SIZE || n > siz || csread(&cs, fd, buf + o, n - o, CS_EXACT) != n - o) return -1;
return n;
}