[Vm-dev] serial plugin crash on unix

[David T. Lewis]

On Sat, Mar 05, 2011 at 04:00:03PM -0800, Markus Lampert wrote:
>  
> Hi,
> 
> the serial plugin for unix (4.4.7.2357) can take the vm down. The following code 
> 
> demonstrates the issue:
> 
> s := SerialPort new.
> 40 timesRepeat: [
>     s openPort: '/dev/ttyS0'.
>     s close]
> 
> I have attached a version of sqUnixSerial.c which fixes the problem. It allows 
> for 32 _different_ serial ports to be opened and closed (as often as necessary). 
> 
> It also prevents the segmentation fault. If more than 32 different serial ports 
> are attempted to be opened the request fails.
> 
> The changes are in line 202, and 220 - 352.

Thanks Markus,

This is on Mantis at http://bugs.squeak.org/view.php?id=7610, and I will
forward your fix to Ian also. It looks very good to me although I did not
test it.

> 
> In the current implementation (trunk) it is not possible to find out if 
> #openPort: was successful or not and I don't know how to fix that.

I am not a user of the serial port plugin, but it sounds like this would
be easy to fix. It looks like the support code returns 0 on success and
-1 on failure, so we could pass that back as the result of the primitive,
or return true/false as the result of the primitive call. Would something
like that help?

Dave