[PATCH 1/1] [Jaunty] UBUNTU: clean up module dependancy information on package removal/purge

[Tim Gardner]

Andy Whitcroft wrote:
> Bug: #399773
> 
> Currently when we purge (dpkg -P) a kernel image we emit the following
> warning and fail to clean up the /lib/modules/<version> directory:
> 
>   rmdir: failed to remove `/lib/modules/2.6.28-1-ub-generic':
> 							Directory not empty
>   dpkg - warning: while removing linux-image-2.6.28-1-ub-generic,
> 	directory `/lib/modules/2.6.28-1-ub-generic' not empty so not removed.
> 
> This may be triggered by a number of things:
> 
> 1) recently depmod started producing a new map file modules.seriomap,
>    which we do not know about and do not purge,
> 2) if the kernel-header files are installed there is a build symbolic
>    link in this directory,
> 3) if the kernel-source files are installed there is a source symbolic
>    link in this directory, and
> 4) it is possible to have an updates directory here from the dkms
>    system.
> 
> When these are encountered we fail to clear the directory and our
> unconditional directory remove will fail leading to this missleading
> warning.
> 
> When examining the prerm and postrm handling for this package a number
> of things are apparent:
> 
> 1) the main dependancy information modules.dep is removed on a normal
>    package removal (non-purge),
> 2) the remaining dependancy information modules.aliases,
>    modules.symbols, and modules.*map are only removed on a purge, and
> 3) during a purge we attempt to remove files belonging to other
>    packages the build and source links (although the code will fail to
>    remove them as they are links and not files).
> 
> If we consider the official difference between a module remove and a purge
> we find that a purge is meant to also take away any local configuration
> files for this package.  These dependancy files are not configuration
> files for the module loader, those are all in /etc/modprobe.d these are
> all data generated by the install of the kernel package and indeed are
> all overwritten without comment on a reinstall.  Basically they should
> be considered in the same manner as the modules.dep file and removed
> when the package is removed.
> 
> This patch fixes up this whole lot, it:
> 
> 1) moves removal of all dependancy related files over to prerm with the
>    removal of modules.dep,
> 2) adds the new modules.seriomap file to the list of files to be removed, and
> 3) removes build and source from the removal list.
> 
> This also fixes the original issue (the warning) by moving removal to the
> prerm phase, so that the files are removed before the primary directory
> deletion is attempted.  This allows the normal reference counting for
> this directory to work as normal.  The directory being removed when all
> packages storing files within are removed from the system.
> 
> Signed-off-by: Andy Whitcroft <apw at canonical.com>
> ---
>  debian/control-scripts/postrm |   23 -----------------------
>  debian/control-scripts/prerm  |   18 +++++++++++++++---
>  2 files changed, 15 insertions(+), 26 deletions(-)
> 

I think this looks right according to Debian policy. Everything being
removed is either part of the original package or was generated as a
side effect of the install.

Ben - since you're our resident DD, what do you think?

rtg
-- 
Tim Gardner tim.gardner at canonical.com