From bb7a1b67c7301f85640d2bdca6278b71215a5766 Mon Sep 17 00:00:00 2001
From: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Date: Wed, 3 Aug 2022 11:03:53 -0300
Subject: [PATCH] kdump-load.sh: Clean-up old/useless kdump initrd files

The kdump-steamos tooling creates an initrd file based in the running
kernel version for kdump, during package installation (even if kdump
is not the default crash collection mechanism). Such file lives in
the /home partition.

When SteamOS image is upgraded, with a new kernel, there is a mechanism
to create a new initrd either manually or automatically, just before the
kdump load; in the end, we may have lots of initrds (one per kernel
version ever installed), but we don't have currently a way to clear that.

Well, until now. We hereby introduce such a simple mechanism, to prevent
waste of precious /home space with useless initrd files. It works by
comparing installed kernels [0] with the kdump-initrd-* files in /home,
and if we have some of these kdump initrds that have no match with any
installed kernel, they are removed (and such operation is logged in the
systemd journal).

[0] Definition: installed kernel in our context is a kernel that
has a modules folder in /lib/modules .

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
---
 kdump-load.sh | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/kdump-load.sh b/kdump-load.sh
index 4737929..60be97f 100644
--- a/kdump-load.sh
+++ b/kdump-load.sh
@@ -64,6 +64,27 @@ create_initrd() {
 	export DRACUT_NO_XATTR=${DRACUT_XATTR}
 }
 
+#  This routine performs a clean-up by deleting the old/useless remaining
+#  kdump initrd files.
+cleanup_unused_initrd() {
+	INSTALLED_KERNELS="${KDUMP_FOLDER}/.installed_kernels"
+
+	find /lib/modules/* -maxdepth 0 -type d -exec basename {} \;>"${INSTALLED_KERNELS}"
+
+	find "${KDUMP_FOLDER}"/* -name "kdump-initrd*" -type f -print0 | while IFS= read -r -d '' file
+	do
+		FNAME="$(basename "${file}" .img)"
+		KVER="${FNAME#kdump-initrd-}"
+		if ! grep -q "${KVER}" "${INSTALLED_KERNELS}" ; then
+			rm -f "${KDUMP_FOLDER}/${FNAME}.img"
+			logger "kdump-steamos: removed unused file \"${FNAME}.img\""
+		fi
+	done
+
+	rm -f "${INSTALLED_KERNELS}"
+}
+
+
 if [ ! -s "/usr/share/kdump/kdump.conf" ]; then
 	logger "kdump-steamos: /usr/share/kdump/kdump.conf is missing, aborting."
 	exit 0
@@ -106,6 +127,7 @@ if [ "${USE_PSTORE_RAM}" -eq 1 ]; then
 		if modprobe ramoops mem_address=0x"${MEM_START}" mem_size=${MEM_REQUIRED} record_size=${RECORD_SIZE}; then
 			#  If Pstore is set, update grub.cfg to avoid reserving crashkernel memory.
 			logger "kdump-steamos: pstore-RAM was loaded successfully"
+			cleanup_unused_initrd
 			grub_update pstore
 			exit 0
 		fi
@@ -118,6 +140,7 @@ if [ "${USE_PSTORE_RAM}" -eq 1 ]; then
 		#  no point in continuing since kdump cannot work.
 fi
 
+cleanup_unused_initrd
 grub_update kdump
 
 #  Stolen from Debian kdump