integer-overflow.rb

unsigned long ruby_strtoul(const char *str, char **endptr, int base);
#define STRTOUL(str, endptr, base) (ruby_strtoul((str), (endptr), (base)))
// ....
static VALUE
pack_pack(int argc, VALUE *argv, VALUE ary)
{
// ...
    long len, idx, plen;

// ....

	else if (ISDIGIT(*p)) {
	    errno = 0;
	    len = STRTOUL(p, (char**)&p, 10);
	    if (errno) {
		rb_raise(rb_eRangeError, "pack length too big");
	    }
	}