RFR: JDK-8313804: JDWP support for -Djava.net.preferIPv6Addresses=system [v4]

[Alex Menkov]

On Tue, 19 Sep 2023 15:41:23 GMT, Liam Miller-Cushon <cushon at openjdk.org> wrote:

>> Please consider this fix for [JDK-8313804](https://bugs.openjdk.org/browse/JDK-8313804), which adds support to JDWP for `-Djava.net.preferIPv6Addresses=system`. Previously it only handled `-Djava.net.preferIPv6Addresses=true` and `-Djava.net.preferIPv6Addresses=false`.
>
> Liam Miller-Cushon has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix pre-existing typo

The loop is not needed for AF_UNSPEC, just make it clear:

    // Try to find bind address of preferred address family first (if java.net.preferIPv6Addresses != "system").
    if (preferredAddressFamily != AF_UNSPEC) {
        for (ai = addrInfo; ai != NULL; ai = ai->ai_next) {
            if (ai->ai_family == preferredAddressFamily) {
                listenAddr = ai;
                break;
            }
        }
    }

    if (listenAddr == NULL) {
        // No address of preferred address family found or java.net.preferIPv6Addresses == "system",
        // use the first address returned by getaddrinfo.
        listenAddr = &(addrInfo[0]);
    }

-------------

PR Comment: https://git.openjdk.org/jdk/pull/15796#issuecomment-1726658095