RFR: 7903730: Enhance the agentvm to be tolerant to unexpected connection on the port the Agent listens on for handshake with the AgentServer [v3]

[Jaikiran Pai]

On Thu, 23 May 2024 13:27:03 GMT, Mark Sheppard <msheppar at openjdk.org> wrote:

>> Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   reduce the scope of the try/catch and fix potential short read() issue
>
> src/share/classes/com/sun/javatest/regtest/agent/AgentServer.java line 68:
> 
>> 66:      * to complete the communication handshake
>> 67:      */
>> 68:     public static final byte[] JTREG_AGENT_HANDSHAKE_MAGIC = "jtreg".getBytes(US_ASCII);
> 
> I was developing a similar PoC for AgentSevre to Agent connectivity
> I used the pattern "Hello Agent:" + id 
> using the Agent id in the connection string, which the Agent compared with its own id as a condition of "accepting" the AgentServer connection

I had given that a thought too - the random handshake bytes that I note in a previous comment of mine https://github.com/openjdk/jtreg/pull/195#issuecomment-2121551694 is a variant of this approach where each `AgentServer` process handshakes with the `Agent` using a different handshake data. For reasons I state in that other comment, I felt that using a dynamic handshake value isn't adding much value and so decided to use a static handshake value instead.

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PR Review Comment: https://git.openjdk.org/jtreg/pull/195#discussion_r1631089031