debian/apt.auto-removal.sh

   1 #!/bin/sh
   2
   3 set -e
   4
   5 # Author: Steve Langasek <steve.langasek@canonical.com>
   6 #
   7 # Mark as not-for-autoremoval those kernel packages that are:
   8 #  - the currently booted version
   9 #  - the kernel version we've been called for
  10 #  - the latest kernel version (determined using rules copied from the grub
  11 #    package for deciding which kernel to boot)
  12 #  - the second-latest kernel version, if the booted kernel version is
  13 #    already the latest and this script is called for that same version,
  14 #    to ensure a fallback remains available in the event the newly-installed
  15 #    kernel at this ABI fails to boot
  16 # In the common case, this results in exactly two kernels saved, but it can
  17 # result in three kernels being saved.  It's better to err on the side of
  18 # saving too many kernels than saving too few.
  19 #
  20 # We generate this list and save it to /etc/apt/apt.conf.d instead of marking
  21 # packages in the database because this runs from a postinst script, and apt
  22 # will overwrite the db when it exits.
  23
  24 config_file=/etc/apt/apt.conf.d/01autoremove-kernels
  25
  26 installed_version="$1"
  27 running_version="$(uname -r)"
  28
  29
  30 version_test_gt ()
  31 {
  32         local version_test_gt_sedexp="s/[._-]\(pre\|rc\|test\|git\|old\|trunk\)/~\1/g"
  33         local version_a="`echo "$1" | sed -e "$version_test_gt_sedexp"`"
  34         local version_b="`echo "$2" | sed -e "$version_test_gt_sedexp"`"
  35         dpkg --compare-versions "$version_a" gt "$version_b"
  36         return "$?"
  37 }
  38
  39 list=$(dpkg -l 'linux-image-[0-9]*'|awk '/^ii/ { print $2 }' | sed -e's/linux-image-//')
  40
  41 latest_version=""
  42 previous_version=""
  43 for i in $list; do
  44         if version_test_gt "$i" "$latest_version"; then
  45                 previous_version="$latest_version"
  46                 latest_version="$i"
  47         elif version_test_gt "$i" "$previous_version"; then
  48                 previous_version="$i"
  49         fi
  50 done
  51
  52 if [ "$latest_version" != "$installed_version" ] \
  53    || [ "$latest_version" != "$running_version" ] \
  54    || [ "$installed_version" != "$running_version" ]
  55 then
  56         # We have at least two kernels that we have reason to think the
  57         # user wants, so don't save the second-newest version.
  58         previous_version=
  59 fi
  60
  61 kernels=$(sort -u <<EOF
  62 $latest_version
  63 $installed_version
  64 $running_version
  65 $previous_version
  66 EOF
  67 )
  68
  69 cat > "$config_file".dpkg-new <<EOF
  70 # File autogenerated by $0, do not edit
  71 APT
  72 {
  73   NeverAutoRemove
  74   {
  75 EOF
  76 for kernel in $kernels; do
  77         echo "    \"^linux-image-$kernel.*\";" >> "$config_file".dpkg-new
  78         echo "    \"^linux-image-extra-$kernel.*\";" >> "$config_file".dpkg-new
  79         echo "    \"^linux-signed-image-$kernel.*\";" >> "$config_file".dpkg-new
  80 done
  81 cat >> "$config_file".dpkg-new <<EOF
  82   };
  83 };
  84 EOF
  85 mv "$config_file".dpkg-new "$config_file"