[linux-base][IHGFB] use linux-update-symlinks in xx-update-initrd-links

[Dimitri John Ledkov]

Currently there is inconsistency between the commands that
linux-image.deb package installation calls, and what installkernel script calls.

In linux-image postinst linux-update-symlinks is called; whereas
installkernel script does not call it.

Rewrite xx-update-initrd-links from custom implementation, to a call
to linux-update-symlinks but only when installkernel script calls the
postinst.d run-parts. This way installkernel does exactly what
linux-image.deb installation would do, including honoring settings in
/etc/kernel-img.conf that installers have been providing in older
series.

Drop duplicated calls to initramfs-tools, multiple postinst.d must not
call update-initramfs. postinst.d snippted to do that already is
called and shipped by the initramfs-tools package.

diff -Nru linux-base-4.5ubuntu7/debian/changelog linux-base-4.5ubuntu8/debian/changelog
--- linux-base-4.5ubuntu7/debian/changelog	2021-05-17 16:55:34.000000000 +0100
+++ linux-base-4.5ubuntu8/debian/changelog	2021-05-27 10:43:52.000000000 +0100
@@ -1,3 +1,12 @@
+linux-base (4.5ubuntu8) impish; urgency=medium
+
+  * Rewrite xx-update-initrd-links to use linux-update-symlinks. This will
+    now make installkernel behaviour match the linux-image-*.postinst
+    behaviour exactly with respect to creating & updating vmlinu? and
+    initrd.img symlinks in / or /boot. LP: #1929255
+
+ -- Dimitri John Ledkov <dimitri.ledkov at canonical.com>  Thu, 27 May 2021 10:43:52 +0100
+
 linux-base (4.5ubuntu7) impish; urgency=medium
 
   * Check for update-initramfs being installed before running the postinst
diff -Nru linux-base-4.5ubuntu7/debian/rules linux-base-4.5ubuntu8/debian/rules
--- linux-base-4.5ubuntu7/debian/rules	2020-06-25 18:23:24.000000000 +0100
+++ linux-base-4.5ubuntu8/debian/rules	2021-05-27 10:43:52.000000000 +0100
@@ -7,3 +7,7 @@
 ifeq ($(filter nocheck,$(DEB_BUILD_OPTIONS)),)
 	perl -Ilib -MTest::Harness -e 'runtests(@ARGV)' lib/t/*.t
 endif
+
+override_dh_install:
+	dh_install
+	chmod -v +x debian/linux-base/etc/kernel/postinst.d/*
diff -Nru linux-base-4.5ubuntu7/etc/kernel/postinst.d/xx-update-initrd-links linux-base-4.5ubuntu8/etc/kernel/postinst.d/xx-update-initrd-links
--- linux-base-4.5ubuntu7/etc/kernel/postinst.d/xx-update-initrd-links	2021-05-17 16:55:34.000000000 +0100
+++ linux-base-4.5ubuntu8/etc/kernel/postinst.d/xx-update-initrd-links	2021-05-27 10:43:32.000000000 +0100
@@ -1,88 +1,24 @@
 #!/bin/sh
 set -e
 
-command -v update-initramfs >/dev/null 2>&1 || exit 0
-
-VERBOSE=true
-
-# If softlinks are maintained, then either under /boot or otherwise /. If
-# neither location contains a vmlinuz, then no softlinks are maintained.
-if [ -L /boot/vmlinu? ]; then
-	dir="/boot/"
-elif [ -L /vmlinu? ]; then
-	dir="/"
-else
-	dir=""
-fi
-
-if [ "$dir" = "" ]; then
-	exit 0
-fi
-
-# avoid running multiple times
-if [ -n "$DEB_MAINT_PARAMS" ]; then
-	eval set -- "$DEB_MAINT_PARAMS"
-	if [ -z "$1" ] || [ "$1" != "configure" ]; then
-		exit 0
-	fi
-fi
-
-create_link() {
-	local tgt=$1
-	local src=$2
-	local dir=$(dirname $src)
-	local kver=${tgt#initrd.img*-}
-
-	# Running installkernel multiple times with the same kernel will
-	# create backups of the binary in the form of vmlinu?-<ver>.old
-	# However by then the modules have been replaced and also there is
-	# no way to build the initramfs with that name.
-	if [ ! -f "${dir}/${tgt}" ]; then
-		case $tgt in
-		initrd.img-*.old)
-			# installkernel should create a copy of the initrd
-			# when it copies a kernel image. This is only a hack
-			# before there is no matching file at all.
-			kver=${kver%.old}
-			cp ${dir}/initrd.img-$kver ${dir}/$tgt
-			;;
-		*)
-			# This is present just as double safety net. By all means
-			# the actual initrd should already be created by a previous
-			# postinst script.
-			INITRAMFS_TOOLS_KERNEL_HOOK=1 \
-				update-initramfs -c -k ${kver}
-			;;
-		esac
-	fi
-
-	$VERBOSE && echo "Softlink: ${src} -> ${tgt}"
-	cd ${dir} && ln -sf ${tgt} ${src}
-}
-
-$VERBOSE && echo "Testing softlinks in $dir..."
-
-for f in $(find $dir -maxdepth 1 -regex '.*vmlinu.\(\.old\)?'); do
-	if [ -e $f ]; then
-		kernel=$(basename $f)
-		initrd="initrd.img${kernel#vmlinu?}"
-		tgt_kernel="$(readlink $f)"
-		tgt_initrd="initrd.img${tgt_kernel#vmlinu?}"
-		if [ ! -L "${dir}${initrd}" -o ! -e "${dir}${initrd}" ]; then
-			$VERBOSE && echo "${dir}${initrd} does not exist or is not a link"
-			create_link ${tgt_initrd} ${dir}${initrd}
-		else
-			cur_initrd=$(readlink ${dir}${initrd})
-			if [ "${cur_initrd}" != "${tgt_initrd}" ]; then
-				$VERBOSE && echo "${dir}${initrd} invalid target (${cur_initrd})"
-				create_link ${tgt_initrd} ${dir}${initrd}
-			else
-				$VERBOSE && echo "${dir}${initrd} -> ${tgt_initrd} (ok)"
-			fi
-		fi
-	else
-		$VERBOSE && echo "Broken link: $f (skip)"
-	fi
-done
+# installkernel script calls postinst.d without any DEB_MAINT_PARAMS set
+# linux-image-* postinst calls postinst.d with DEB_MAINT_PARAMS set
+# do nothing in case linux-image-* calls this, as it already calls `linux-update-symlinks`
+[ -z "$DEB_MAINT_PARAMS" ] || exit 0
+
+# installkernel must call postinst.d with two args, version & image_path
+version="$1"
+image_path="$2"
+
+[ -n "$version" ] || exit 0
+[ -n "$image_path" ] || exit 0
+
+# call linux-update-symlinks in install mode, which will correctly
+# update vmlinuz & initrd.img symlinks. Even if initrd.img does not
+# exist yet, or has already been created by the initramfs-update
+# postinst.d hook. It will also honor kernel_img.conf settings to
+# link_in_boot yes/no. Thus matching behaviour of linux-image-*
+# postinst call to linux-update-symlinks.
+linux-update-symlinks install $version $image_path
 
 exit 0