ref: ae65ffa1cdffa379eb9a7f248cee5bb017bc4c06
dir: /sys/src/cmd/unix/u9fs/safecpy.c/
#include <stdio.h>
void
safecpy(char *to, char *from, int tolen)
{
int fromlen;
memset(to, 0, tolen);
fromlen = from ? strlen(from) : 0;
if (fromlen > tolen)
fromlen = tolen;
memcpy(to, from, fromlen);
}