On Sat 21 Aug 2021 at 19:17:31 (+0530), didar wrote:
> On Thu, Aug 19, 2021 at 10:45:44PM -0500, David Wright wrote:
> > On Thu 19 Aug 2021 at 08:01:24 (-0400), songbird wrote:
> > > David Wright wrote:
> > > > On Wed 18 Aug 2021 at 20:55:12 (-0400), songbird wrote:
> > > >> let's suppose you have a directory where there are
> > > >> various scripts, libraries, programs, data, etc.
> > > >>
> > > >> you want to know exactly which other scripts, libraries,
> > > >> etc. use them and to log each caller to know the name so
> > > >> it can be tracked down (location would be nice too, but
> > > >> that could be found later if needed).
> > > >>
> > > >> i don't need to keep the information in a database as
> > > >> just having the log file will be enough.
> > > >>
> > > >> how would you do this?
> > > >>
> > > >> this isn't a homework assignment i'm just curious how
> > > >> easy or hard this would be to accomplish.
> > > >
> > > > Easy.
> > > >
> > > > $ inotifywait -m -e access --timefmt "%F %T" --format "%T %f"
> > > > the-directory/
> > > >
> > > > To try it, just type in that line, using a sensible directory name.
> > > > (The package name to install first is inotify-tools.)
> > > >
> > > > Change the formats to taste. Pipe into a while IFS=$'\n' read
> > > > Filename ; do
> > > > loop if you want to do something with the output. See:
> > > >
> > > > https://lists.debian.org/debian-user/2021/03/msg01494.html
> > > >
> > > > for a real script (waiting on close-writeable-file, rather than just
> > > > access) that I use a lot for stealing files from FireFox's cache
> > > > (~/.cache/mozilla/firefox/foo.bar.profile/cache2/entries/).
> > >
> > > thanks! very interesting! :)
> > >
> > > thank you to others who replied also. :)
> > >
> > > i was wondering if there was a general tool available as on
> > > debian-devel they are talking about usr-merge and if there was a
> > > simple way to find out who's using /bin and such instead of
> > > /usr/bin,
> >
> > No, that's a different problem. My solution addresses a directory,
> > hence the change in Subject line. You'd have to dive deeper into
> > inotify and inotify_add_watch, to see whether you can specify the
> > inode of the /bin symlink separately from that for /usr/bin.
> >
> > $ ls -Glidg /bin /usr/bin
> > 12 lrwxrwxrwx 1 7 Apr 3 2020 /bin -> usr/bin
> > 261634 drwxr-xr-x 2 69632 Aug 11 19:10 /usr/bin
> > $
> >
To be more explicit, my understanding of symlinks is that they're
a property of the filesystem, and so are resolved in the kernel,
likely somewhere in fs/ext{2,4}. So nothing in userspace is likely
to be aware of whether a filename was referenced through a symlink.
> There is an "auditd" package - a Red Hat origin tool/subsystem. It's available
> on Bullseye, but, I have not tried it recently. It might be what you are
> looking
> for.
I would revise my "Easy", above, to Hard. You would have to write
rules to trigger logging just the right events in the kernel, and then
write a program to wade through the log, which will be pouring in from
all the processes triggering those events. Plus deal with the slowdown
from a heavy overhead if the rules aren't adequately focussed.
When the OP replied to my first post, I ran my one-liner on /bin,
and then tried running a few binaries by invoking them through /bin
and /usr/bin (which, of course, didn't reveal anything interesting).
However, I could only do this for ~50 seconds of each minute because
my crontab would spew a couple of screenfuls every time it triggered.
Let us know how it goes, should you attempt it.
Cheers,
David.
