[PATCH] util/grub.d/10_linux: Improve initramfs detection

[Oskari Pirhonen]

Prefer using a *.old initramfs for *.old kernels if it exists. Otherwise
look for an initramfs without the suffix.

Also add detection for initramfs of the form *.img.old. For example,
Gentoo's sys-kernel/genkernel installs it as initramfs-*.img and moves
any existing one to initramfs-*.img.old.

Signed-off-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
---
 util/grub.d/10_linux.in | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index ca068038e..4a666c317 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -215,19 +215,34 @@ while [ "x$list" != "x" ] ; do
   done
 
   initrd_real=
-  for i in "initrd.img-${version}" "initrd-${version}.img" 
"initrd-${version}.gz" \
-          "initrd-${version}" "initramfs-${version}.img" \
-          "initrd.img-${alt_version}" "initrd-${alt_version}.img" \
-          "initrd-${alt_version}" "initramfs-${alt_version}.img" \
-          "initramfs-genkernel-${version}" \
-          "initramfs-genkernel-${alt_version}" \
-          "initramfs-genkernel-${GENKERNEL_ARCH}-${version}" \
-          "initramfs-genkernel-${GENKERNEL_ARCH}-${alt_version}"; do
-    if test -e "${dirname}/${i}" ; then
-      initrd_real="${i}"
-      break
-    fi
-  done
+  # Prefer to match *.old kernel with *.old initramfs if it exists
+  if [ "${alt_version}" != "${version}" ]; then
+    for i in "initrd.img-${version}" "initrd-${version}.img" \
+          "initrd-${alt_version}.img.old" "initrd-${version}.gz" \
+          "initrd-${alt_version}.gz.old" "initrd-${version}" \
+          "initramfs-${version}.img" "initramfs-${alt_version}.img.old" \
+          "initramfs-genkernel-${version}" \
+          "initramfs-genkernel-${GENKERNEL_ARCH}-${version}"; do
+      if test -e "${dirname}/${i}" ; then
+        initrd_real="${i}"
+        break
+      fi
+    done
+  fi
+
+  # alt_version == version or *.old initramfs not found
+  # use alt_version to handle both cases at once
+  if [ -z "${initrd_real}" ]; then
+    for i in "initrd.img-${alt_version}" "initrd-${alt_version}.img" \
+          "initrd-${alt_version}.gz" "initrd-${alt_version}" \
+          "initramfs-${alt_version}.img" "initramfs-genkernel-${alt_version}" \
+          "initramfs-genkernel-${GENKERNEL_ARCH}-${alt_version}"; do
+      if test -e "${dirname}/${i}" ; then
+        initrd_real="${i}"
+        break
+      fi
+    done
+  fi
 
   initrd=
   if test -n "${initrd_early}" || test -n "${initrd_real}"; then
-- 
2.34.1