How to get the newly-installed version within a Debian postinst script?

Per the Debian Policy Manual, my postinst script is getting called at upgrade and configure time, as "postinst configure old-version", where old-version is the previously installed version (possibly null). I want to determine new-version, i.e. the version that is currently being configured (upgraded to).

The environment variable $DPKG_MAINTSCRIPT_PACKAGE contains the package name; there does not seem to be an equivalent _VERSION field. /var/lib/dpkg/status gets updated AFTER postinst runs, so I can't seem to parse it out of there, either.

Any ideas?

This is the best method I have found to resolve this issue is to use a place-holder variable in your .postinst (or other control files):

case "$1" in
    configure)
        new_version="__NEW_VERSION__"
        # Do something interesting interesting with $new_version...
        ;;
    abort-upgrade|abort-remove|abort-deconfigure)
        # Do nothing
        ;;
    *)
        echo "Unrecognized postinst argument '$1'"
        ;;
esac

Then in debian/rules, replace the placeholder variable with the proper version number at build time:

# Must not depend on anything. This is to be called by
# binary-arch/binary-indep in another 'make' thread.
binary-common:
    dh_testdir
    dh_testroot
    dh_lintian
    < ... snip ... >

    # Replace __NEW_VERSION__ with the actual new version in any control files
    for pkg in $$(dh_listpackages -i); do \
        sed -i -e 's/__NEW_VERSION__/$(shell $(SHELL) debian/gen_deb_version)/' debian/$$pkg/DEBIAN/*; \
    done

    # Note dh_builddeb *must* come after the above code
    dh_builddeb

The resulting .postinst snippet, found in debian/<package-name>/DEBIAN/postinst, will look like:

case "$1" in
    configure)
        new_version="1.2.3"
        # Do something interesting interesting with $new_version...
        ;;
    abort-upgrade|abort-remove|abort-deconfigure)
        # Do nothing
        ;;
    *)
        echo "Unrecognized postinst argument '$1'"
        ;;
esac

VERSION=$(zless /usr/share/doc/$DPKG_MAINTSCRIPT_PACKAGE/changelog* \
     | dpkg-parsechangelog -l- -SVersion')

Advantages over other solutions here:

Works regardless of whether changelog is compressed or not
Uses dpkg's changelog parser instead of regular expressions, awk, etc.

I use the following somewhat dirty command in the postinst script:

NewVersion=$(zcat /usr/share/doc/$DPKG_MAINTSCRIPT_PACKAGE/changelog.gz | \
  head -1 | perl -ne '$_=~ /.*\((.*)\).*/; print $1;')

Add the following to the debian/rules:

override_dh_installdeb:
    dh_installdeb
    for pkg in $$(dh_listpackages -i); do \
        sed -i -e 's/__DEB_VERSION__/$(DEB_VERSION)/' debian/$$pkg/DEBIAN/*; \
    done

It will replace any occurrence of __DEB_VERSION__ in your debian scripts with the version number.

By the time postinst is run, all the package files have been installed and dpkg's data base has been updated, so you can get the just installed version with:

dpkg-query --show --showformat='${Version}' packagename

Why can't you hard-code the version into the postinst script at packaging time?

Try this:

VERSION=`dpkg -s $DPKG_MAINTSCRIPT_PACKAGE | sed -n 's/^Version: //p'`

来源：https://stackoverflow.com/questions/715313/how-to-get-the-newly-installed-version-within-a-debian-postinst-script

标签

shell

debian

packages