/*  * 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>#include <bio.h>#include "authcmdlib.h" /* *  read exactly len bytes */intreadn(int fd, char *buf, int len){	int m, n; 	for(n = 0; n < len; n += m){		m = read(fd, buf+n, len-n);		if(m <= 0)			return -1;	}	return n;}