git: 9front

ref: f4690f92b3e8d4a5c6d97c58d41218ade94e9901
dir: /sys/src/cmd/auth/lib/readn.c/

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#include <u.h>
#include <libc.h>
#include <bio.h>
#include "authcmdlib.h"

/*
 *  read exactly len bytes
 */
int
readn(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;
}