/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>  /* *  After a fork with fd's copied, both fd's are pointing to *  the same Chan structure.  Since the offset is kept in the Chan *  structure, the seek's and read's in the two processes can *  compete at moving the offset around.  Hence the unusual loop *  in the middle of this routine. */static longoldtime(long *tp){	char b[20];	static int f = -1;	int i, retries;	long t; 	memset(b, 0, sizeof(b));	for(retries = 0; retries < 100; retries++){		if(f < 0)			f = open("/dev/time", OREAD|OCEXEC);		if(f < 0)			break;		if(seek(f, 0, 0) < 0 || (i = read(f, b, sizeof(b))) < 0){			close(f);			f = -1;		} else {			if(i != 0)				break;		}	}	t = atol(b);	if(tp)		*tp = t;	return t;} longtime(long *tp){	vlong t; 	t = nsec()/1000000000LL;	if(t == 0)		t = oldtime(0);	if(tp != nil)		*tp = t;	return t;}