[Libguestfs] [PATCH] launch: rework handling of --enable-valgrind-daemon

[Richard W.M. Jones]

We had a chat about this on IRC, and I'm not very happy about any
patch that requires a special ./configure flag.  We should find a way
to enable this functionality for everyone in all builds, without
impacting anyone who doesn't want to use it.

I think:

 - remove the --enable-valgrind-daemon, for reasons outlined above
   (I posted a patch to do that yesterday)

 - have a new backend setting, just like you proposed, except it
   wouldn't be conditional on any configure setting

 - when (1) the backend setting is true and (2) valgrind is present
   in the appliance, the init script should run `valgrind guestfsd'

 - output from valgrind would go to stderr, where it is picked up by
   the normal verbose output (so we don't need a special socket)

This doesn't handle the guestfsd shutdown case (but nor does the
current code, which is both racy on shutdown and introduces separate
shutdown paths for --enable-valgrind-daemon and ordinary
configurations).  But we can punt on that until later.  The above
would detect all memory errors except for memory leaks.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top