Extending fcopy

[Michael Tautschnig]

> Am Freitag, 8. Dezember 2006 16:48 schrieben Sie:
> 
> > > > > - some -k/--keep option (which I'd rather call --keep-permissions :-)
> > [...]
> > If a file permission get borked it will never be fixed by an softupdate.
> 
> you don't need to use the -k (keep-permissions) option, so spftupdate can fix 
> it. But why should it be broken anyway?
>
Never trust your system. Never.

> > In the case that it's not root:root 644 it has in most cases a special
> > reason.  If the file is missing there noting to preserve, what to use then?
> 
> then use -M, -m or source file permissions as it is right now.
> 

I'd say the patch should add 2 warning:
- One to be displayed in case there is destination file
- Anotherone in the man page: WARNING: -k might introduce a security hole in
  case the permissions of the destination file have been altered unexpectedly.

Then, well, it's up to the FAI-user to use -k or not.


> > [...]
> > > i tried to use exit code, too:
> > [...]
> > > > this way you can say 
> > >
> > >    fcopy ... /etc/postgresql && /etc/init.d/postgresql restart || exit 1;
> > >
> > > What do you think about using exit codes? First i sort it's not unix
> > > like, but diff does like this, too.
> >
> > Add $? to your prompt and you'll see that much more apps do it like this ;)
> > So both methods can coexists with file list turned on (or off) with a file
> > an option.
> 
> i switched this behaviour now after some tests. My patched fcopy now returns 0 
> if no files were changed or 1 if files were changed. I changed because if 
> fcopy returns exit code 1 when nothing was changed it was propagated as the 
> script exit code. But i am still not sure what is nicer, to return exit code 
> 1 if files were changed or return exit code 1 if files were NOT changed.
>

Return codes and fcopy to me is a somewhat strange thing. The current default
behaviour is that preserving a file is treated as an error and a non-zero exit
status is returned.

In my opinion fcopy should only return something other than 0 if an error
occurred. And preserving a file is not an error IMHO.

As such I'd go for the following: Return 0 unless anything inside fcopy (which
includes preinst/postinst) went wrong. To find out, whether files have been
altered or not (which includes changing permissions), I'd prefer an output like
the following (more or less proper perl, but I guess you get the idea):

if( $changed )
{
  printf "fcopy is updating $file:\n";
  printf "\t Copied $src to $dest\n" if( $copied );
  printf "\t Permissions set to $perm\n" if( $perm_changed );
}

Then, one could do the following:

fcopy ... /etc/postgresql | grep -q "fcopy is updating" && /etc/init.d/postgresql restart 

Best,
Michael


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