pack_sockaddr_un

static VALUE
sock_s_pack_sockaddr_un(VALUE self, VALUE path)
{
    struct sockaddr_un sockaddr;
    char *sun_path;
    VALUE addr;

    MEMZERO(&sockaddr, struct sockaddr_un, 1);
    sockaddr.sun_family = AF_UNIX;
    sun_path = StringValueCStr(path);
    if (sizeof(sockaddr.sun_path) <= strlen(sun_path)) {
        rb_raise(rb_eArgError, "too long unix socket path (max: %dbytes)",
            (int)sizeof(sockaddr.sun_path)-1);
    }
    strncpy(sockaddr.sun_path, sun_path, sizeof(sockaddr.sun_path)-1);
    addr = rb_str_new((char*)&sockaddr, sizeof(sockaddr));
    OBJ_INFECT(addr, path);

    return addr;
}