[libvirt-users] Handling connection closes in (older) Sys::Virt

[Daniel P. Berrange]

On Wed, Nov 14, 2012 at 10:15:25AM +0200, Henrik Ahlgren wrote:
> I hope this is the correct mailing list for discussing the Sys::Virt
> Perl module.
> 
> It appears that the most recent version has a new method called
> register_close_callback that, I believe, can be used to catch errors
> when the connection to libvirt is closed, e.g. due to libvirt restart
> or a network related issue. (I've been testing this simply by killing
> the the SSH process in the libvirt server.)
> 
> However, Debian still ships libvirt 0.9.12 in stable backports and
> testing, as probably do many other mainstream distributions. The
> latest Perl bindings that can be installed from CPAN is thus 0.9.12
> and it does not have support for close callbacks. Not only that, when
> a Perl program loses the (ssh) connection to libvirt, Perl just
> crashes:
> 
> Program received signal SIGPIPE, Broken pipe.
> 0x00007ffff73de0d0 in __write_nocancel () from /lib/libpthread.so.0
> 
> Setting a $SIG{PIPE} handler does not seem to help. Is there any
> possibility of a Perl program surviving and gracefully handling a
> closed libvirt connection with libvirt version 0.9.12 or
> older?

You definitely need to figure out how to set the SIGPIPE handler to
'ignore'. libvirt.so does not do this, because it is bad practice for
a library to set application global state like this. Not sure what
you tried, but I'd definitely expect this to work:

 $SIG{'PIPE'} = 'IGNORE';


Daniel
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