[vbox-dev] Good news: Telnet server patch for VirtualBox serial port !

Klaus Espenlaub klaus.espenlaub at oracle.com
Wed Apr 1 09:53:33 UTC 2015


On 31.03.2015 20:35, Alexey Eromenko wrote:
> Several days of work :)
> VirtualBox finally got a serial-telnet-server patch !
> Ugly tricks such as "socat" bridge and "VMware Serial Line Gateway"
> out; Patch in !

really a brilliant contribution - with one catch: your code is using the 
socket API directly (always a risk of subtle bugs on Windows, as winsock 
is a poor copy of the socket API, with surprises all over the place), 
and clearly can only handle IPv4. Would you be willing to spend a few 
extra minutes to convert it to use the TCP server/client functionality 
available in include/iprt/tcp.h (you choose if you want the callbacks or 
the other variant) plus include/iprt/socket.h (for the actual 

All other issues I found while reviewing the code are idle nagging of a 
perfectionist - the most prominent one is shown by your screenshot 
actually: the GUI has a "Create Pipe" checkbox in this case (controlling 
server mode), which is misleadingly named in this context. Far from 
urgent. Your contribution's usefulness outweighs such really tiny 
quirks. It actually might be a task for us, using different wording for 
this option in all cases, in the light of having a new member in the 
list of serial port backends.

> This is especially useful for GNS3 Network Simulator, where we do
> access remote VM's serial port.
> I ask you to include it in the upcoming VirtualBox 4.4, and call it a
> "major new feature" in changelog :)

I definitely want to get this into the coming release. Actually I 
wouldn't postpone it even if you said that you don't have time right now 
to do the socket API cleanup I mentioned above - then it would be IPv4 
only until someone does.

Just a bit sad as with the coming release we want to squash as many 
places as possible which are IPv4 only - it is becoming an annoying 
limitation for some users.

> Download patch + screenshot here:
> https://forums.virtualbox.org/viewtopic.php?f=10&t=66893&p=317052#p317052

All in all a really good quality contribution.

Thanks so far, and we'll see when in the next week or so someone finds 
time to include it (let us know if you want to do the cleanup first, 
would avoid a tiny bit of additional work for is)!


> Enjoy !

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