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/*************************************************************************/
/* (c) Copyright Tai Jin, 1988. All Rights Reserved. */
/* Hewlett-Packard Laboratories. */
/* */
/* Permission is hereby granted for unlimited modification, use, and */
/* distribution. This software is made available with no warranty of */
/* any kind, express or implied. This copyright notice must remain */
/* intact in all versions of this software. */
/* */
/* The author would appreciate it if any bug fixes and enhancements were */
/* to be sent back to him for incorporation into future versions of this */
/* software. Please send changes to tai@iag.hp.com or ken@sdd.hp.com. */
/*************************************************************************/
#ifndef lint
static char RCSid[] = "adjtime.c,v 3.1 1993/07/06 01:04:42 jbj Exp";
#endif
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <time.h>
#include <signal.h>
#include "adjtime.h"
#define abs(x) ((x) < 0 ? -(x) : (x))
static LONG adjthresh = 400L;
static LONG saveup;
_clear_adjtime()
{
saveup = 0L;
}
adjtime(delta, olddelta)
register struct timeval *delta;
register struct timeval *olddelta;
{
struct timeval newdelta;
/* If they are giving us seconds, ignore up to current threshold saved */
if (delta->tv_sec) {
saveup = 0L;
return(_adjtime(delta, olddelta));
}
/* add in, needs check for overflow ? */
saveup += delta->tv_usec;
/* Broke the threshold, call adjtime() */
if (abs(saveup) > adjthresh) {
newdelta.tv_sec = 0L;
newdelta.tv_usec = saveup;
saveup = 0L;
return(_adjtime(&newdelta, olddelta));
}
if (olddelta)
olddelta->tv_sec = olddelta->tv_usec = 0L;
return(0);
}
_adjtime(delta, olddelta)
register struct timeval *delta;
register struct timeval *olddelta;
{
register int mqid;
MsgBuf msg;
register MsgBuf *msgp = &msg;
/*
* get the key to the adjtime message queue
* (note that we must get it every time because the queue might have been
* removed and recreated)
*/
if ((mqid = msgget(KEY, 0)) == -1)
return (-1);
msgp->msgb.mtype = CLIENT;
msgp->msgb.tv = *delta;
if (olddelta)
msgp->msgb.code = DELTA2;
else
msgp->msgb.code = DELTA1;
if (msgsnd(mqid, &msgp->msgp, MSGSIZE, 0) == -1)
return (-1);
if (olddelta) {
if (msgrcv(mqid, &msgp->msgp, MSGSIZE, SERVER, 0) == -1)
return (-1);
*olddelta = msgp->msgb.tv;
}
return (0);
}
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