Re: Erase cache, clean registry in Linux

[lee <lee@yun.yagibdah.de>]

On Wed, Nov 26, 2008 at 10:42:53PM -0800, Kelly Clowers wrote:

> Windows NT 4, 2000 and XP (and I think ME, 98, 95 and NT 3) had
> a hidden file called thumbs.db in each folder that had images that
> had ever been displayed as thumbnails. Sometimes if you download
> peoples image dump rar files, you get the thumbs.db as well.

Yeah, I was already thinking that these thumbnails can be very
compromising and that such a cache is a security problem. When they
are spread all over the place, it's even worse.

> Vista and newer have some central thumbnail store, but I do not
> know the details.

Hm ...

> > Yeah, but I'd need it the other way round: Monitor .thumbnails to see
> > which programs access it.
> 
> Maybe lsof with the loop option and a tight loop? Still seems
> hit or miss to me.

Gimp brought up a message that it cannot create thumbnails. So now I
know at least one program that creates them.

> > Hm, that is not a fix, it's a poor workaround. And when I start
> > nautilus and look at the preferences dialog, there is no mentioning of
> > caching thumbnails whatsoever.
> 
> Gnome would never allow a pref like that in the pref dialog,

Why not? What is that dialog for?

> but you
> can change it with gconf-editor: /desktop/gnome/thumbnail_cache/
> There is an age option and a size option.

That is not a configuration file, it looks like some kind of registry
(shudder). There is no such entry. There is something called
"thumbnailers" --- what happens when I try to remove that?

Why can't they just use a configuration file and have some comments in
it?

> > The cache won't probably be cleaned anyway because I'm already logged
> > in on the console from which I used startx before eventually starting
> > nautilus. Purging the cache only on login is silly anyway: I can stay
> > logged in for months.
> >
> >> I have thought for a while that some sort of lightweight CLI-level
> >> session management (beyond simple shell login and logout scripts)
> >> would be nice for a number of things, including things like this.
> >
> > What is session management?
> 
> Session Managers, along with Display Managers (login screen) and now
> ConsoleKit, deal with auto-starting apps, resuming programs in the position
> and state they were in when you logged out, and handling user switches.

Hm, how do they handle the programs like mutt, emacs, bash and others
that run in screen in yeahconsole or other things running in xterms?
Or plan? Or other X applications? I've written one or two, and when
you forcibly close them (like stopping X from running), you will lose
the data that hasn't been saved. And how would a session manager know
how to start these programs?

> > What the hell is "gnome-mount extension"?
> 
> It handles semiautomatic mounting and unmounting in Gnome.

How do I turn it off? I don't want anything to be mounted
automatically or semi-automatically! Only root can do that --- if
gnome tries to circumvent that, that is a huge security hole and a
bug.

> > What is "gnome-vfs-daemon"?
> 
> gnome-vfs (recently replaced with gvfs and gio) is gnomes
> virtual filesystem, similar to KDEs kio. It handles not only
> file:/// URIs, but also ftp:, http:, smb:, ssh: and others.

Another thing to hide from the user what's going on? How do I turn it
off?

> > Why is there no man page about it? What is "bonobo"-something that
> > sometimes starts running when using gnome programs? And so on ...
> 
> Bonobo is a component model / framework built on CORBA.
> It is related in purpose to MS COM and KDE KParts. Corba
> sucks, and Bonobo use is (very) gradually being phased out.

And what is it? What does it do?

> > Hm, and it doesn't seem to create thumbnails. It didn't give me a
> > message that it can't write to .thumbnails, so something else must be
> > creating them.
> 
> It just does not complain about it. A quick strace showed that
> Nautilus does indeed use ~/.thumbnails.

And again, important information is hidden from the user. I think I
might just remove gnome. Hmm ...


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