ref: ac4840116ef15e2fc65d0e68f7e16d3a8a1aa2f8
dir: /sys/src/cmd/unix/u9fs/safecpy.c/
#include <string.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);
}