Re: [Qemu-devel] [PATCH v15 6/9] module: implement module loading

[Fam Zheng <famz@redhat.com>]

On Mon, 01/13 22:05, Peter Maydell wrote:
> On 13 January 2014 16:59, Paolo Bonzini <pbonzini@redhat.com> wrote:
> > From: Fam Zheng <famz@redhat.com>
> >
> > This patch adds loading, stamp checking and initialization of modules.
> >
> > The init function of dynamic module is no longer directly called as
> > __attribute__((constructor)) in static linked version, it is called
> > only after passed the checking of presense of stamp symbol:
> >
> >     qemu_stamp_$(date +%s$$$RANDOM)
> >
> 
> > +echo "CONFIG_STAMP=`date +%s`_$$_$RANDOM" >> $config_host_mak
> 
> This is not really a good idea because $RANDOM is a bashism
> and our configure script is a generic POSIX shell script. In
> particular if you configure on Ubuntu you're likely to find that /bin/sh
> is dash and $RANDOM silently expands to the empty string.
> 
> (One day I will clean up the tempfile generation stuff to fix
> its misuse of $RANDOM...)
> 

So what's the best way to generate random number here?

> > +void DSO_STAMP_FUN(void);
> > +/* For error message, this function is an identification of qemu module */
> 
> What is this comment trying to say?

Existence of this symbol indicates it *is* a qemu module. Where we continue to
check for existence of DSO_STAMP_FUN, and report it's only the wrong version.

Thanks,
Fam