Re: Enquiry about building a new root file system

[Jean-Christian de Rivaz <jc@eclis.ch>]

Le 22. 08. 14 07:44, Bas Wijnen a écrit :
> On Thu, Aug 21, 2014 at 09:43:13PM -0500, David Lechner wrote:
> > The .preinst files is something that I have not yet taken the time
> > to understand as well as I should yet, so you should not trust me as
> > absolute expert on this. It is my understanding, though, that when
> > multistrap runs, there is nothing in the chroot, so preinst scripts
> > can't run before we unpack because there is no /bin/sh or any of the
> > commands or programs that the scripts will use.
> Preinst scripts may expect all Essential:yes packages (and their
> dependencies) to be installed and configured on the system.  The
> exception is obviously preinst scripts of Essential packages; they may
> expect all those packages to be unpacked.
>
> So the proper order of events would be:
> - unpack essential packages
> - run preinst of essential packages
> - run postinst of essential packages
> - run preinst of other packages
> - unpack other packages
> - run postinst of other packages
>
> I'm not surprised if during bootstrap all Priority:standard and higher
> packages are treated the same, even if not all of them are Essential

Thanks Bas,

I tried this to mimic the suggested proper order according with this 
script called from sudo chroot target:

export LC_ALL=C
export LANG=C
export LANGUAGE=C
export DEBIAN_FRONTEND=noninteractive
export DEBCONF_NONINTERACTIVE_SEEN=true
debconf-set-selections /tmp/debconfseed.txt
essentials_yes=$(dpkg-query -Wf '${Package;-40} ${Essential}\n' | grep " 
yes$" | cut -f1 -d' ')
for package in $essentials_yes; do
    script=/var/lib/dpkg/info/$package.preinst
    if [ -x $script ]; then
        echo "Preinstall essential $package"
        $script install
    fi
done
for package in $essentials_yes; do
    script=/var/lib/dpkg/info/$package.postinst
    if [ -x $script ]; then
        version=$(dpkg-query -Wf '${Version}' $package)
        echo "Postinstall essential $package $version"
        $script configure $version
    fi
done
essentials_no=$(dpkg-query -Wf '${Package;-40} ${Essential}\n' | grep " 
no$" | cut -f1 -d' ')
for package in $essentials_no; do
    script=/var/lib/dpkg/info/$package.preinst
    if [ -x $script ]; then
        echo "Preinstall $package"
        $script install
    fi
done
for package in $essentials_no; do
    script=/var/lib/dpkg/info/$package.postinst
    if [ -x $script ]; then
        version=$(dpkg-query -Wf '${Version}' $package)
        echo "Postinstall $package $version"
        $script configure $version
    fi
done
dpkg --configure -a

My observations so fare:

1) Postinstall essential util-linux raise a insserv error that I don't 
understand at all.
2) Preinstall initscripts systematically raise "dpkg-maintscript-helper: 
error: environment variable DPKG_MAINTSCRIPT_NAME is required" no matter 
his order.
3) Calling the postinst script seem to be somewhat the same effect as 
calling the dpkg --configure -a, but raise more error. Part of the 
problem is maybe related to the fact that the order of the scripts don't 
respect the dependencies order.

After some test, I have found that only preinst of essential packages is 
required before dpkg --configure -a, and that this last command already 
do the rest of the work just well. Running preinst of non-essential 
package don't seem to bring any advantage but raise more error.

Below is my actual script:

export LC_ALL=C
export LANG=C
export LANGUAGE=C
export DEBIAN_FRONTEND=noninteractive
export DEBCONF_NONINTERACTIVE_SEEN=true
debconf-set-selections /tmp/debconfseed.txt
essentials_yes=$(dpkg-query -Wf '${Package;-40} ${Essential}\n' | grep " 
yes$" | cut -f1 -d' ')
for package in $essentials_yes; do
    script=/var/lib/dpkg/info/$package.preinst
    if [ -x $script ]; then
        echo "Preinstall essential $package"
        $script install
    fi
done
dpkg --configure -a

Best Regards,

Jean-Christian