From 8ed7991db8bad4e957670ffa42994e476d431e71 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Sat, 4 Jun 2016 23:37:04 +0100
Subject: [PATCH] linux-image: Make a newly installed kernel the default if the
 package was previously removed

Currently the postinst script distinguishes installation vs upgrade by
checking whether its second argument is empty.  However, it will only
be empty if the package was *never* installed before, or was purged.
If the package has been installed, then removed, and is now being
installed again, it's seen as an upgrade.

Unfortunately dpkg only tells the preinst script whether or not this
is an upgrade.  So create a flag file there, consume it in postinst
and remove it in postrm.
---
 debian/changelog                   | 2 ++
 debian/templates/image.postinst.in | 3 ++-
 debian/templates/image.postrm.in   | 2 ++
 debian/templates/image.preinst.in  | 6 ++++++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/debian/changelog b/debian/changelog
index 49966b0f1..61c4aca20 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -7,6 +7,8 @@ linux (4.6-1~exp3) UNRELEASED; urgency=medium
     for  minimal_swap, no_symlinks, use_hard_links and *_hook parameters in
     /etc/kernel-img.conf (Closes: #730073).
   * linux-image: postrm: Update default symlinks before running hook scripts
+  * linux-image: Make a newly installed kernel the default if the package
+    was previously removed
 
  -- Ben Hutchings <ben@decadent.org.uk>  Sat, 04 Jun 2016 18:33:11 +0100
 
diff --git a/debian/templates/image.postinst.in b/debian/templates/image.postinst.in
index 09960b85e..ebd17df89 100755
--- a/debian/templates/image.postinst.in
+++ b/debian/templates/image.postinst.in
@@ -13,12 +13,13 @@ fi
 
 depmod $version
 
-if [ -z "$2" ]; then
+if [ -f /lib/modules/$version/.fresh-install ]; then
     change=install
 else
     change=upgrade
 fi
 linux-update-symlinks $change $version $image_path
+rm -f /lib/modules/$version/.fresh-install
 
 if [ -d /etc/kernel/postinst.d ]; then
     DEB_MAINT_PARAMS="$*" run-parts --report --exit-on-error --arg=$version \
diff --git a/debian/templates/image.postrm.in b/debian/templates/image.postrm.in
index 9ba8546bd..29e9c8250 100755
--- a/debian/templates/image.postrm.in
+++ b/debian/templates/image.postrm.in
@@ -3,6 +3,8 @@
 version=@abiname@@localversion@
 image_path=/boot/@image-stem@-$version
 
+rm -f /lib/modules/$version/.fresh-install
+
 if [ "$1" != upgrade ] && command -v linux-update-symlinks >/dev/null; then
     linux-update-symlinks remove $version $image_path
 fi
diff --git a/debian/templates/image.preinst.in b/debian/templates/image.preinst.in
index e723bed03..8a5658ecd 100755
--- a/debian/templates/image.preinst.in
+++ b/debian/templates/image.preinst.in
@@ -7,6 +7,12 @@ if [ "$1" = abort-upgrade ]; then
     exit 0
 fi
 
+if [ "$1" = install ]; then
+    # Create a flag file for postinst
+    mkdir -p /lib/modules/$version
+    touch /lib/modules/$version/.fresh-install
+fi
+
 if [ -d /etc/kernel/preinst.d ]; then
     DEB_MAINT_PARAMS="$*" run-parts --report --exit-on-error --arg=$version \
 	      --arg=$image_path /etc/kernel/preinst.d