kernel-grub.bbclass: add a method to install/update for bzImage

While installing a rpm to update kernel on a deployed target, it will update
the boot area and the boot menu with the kernel as the priority but allow
you to fall back to the original kernel as well.

- In kernel-image's preinstall scriptlet, it backs up original kernel to avoid
  probable confliction with the new one.
- In kernel-image's postinstall scriptlet, it modify grub's config file to
  updates the new kernel as the boot priority.

[YOCTO #4104]

(From OE-Core rev: 8d872e7712a62fa4313a1114a92907c29beffa2e)

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 90 insertions, 0 deletions

diff --git a/meta/classes/kernel-grub.bbclass b/meta/classes/kernel-grub.bbclass
new file mode 100644
index 0000000000..70564f010a
--- /dev/null
+++ b/meta/classes/kernel-grub.bbclass
@@ -0,0 +1,90 @@
+#
+# While installing a rpm to update kernel on a deployed target, it will update
+# the boot area and the boot menu with the kernel as the priority but allow
+# you to fall back to the original kernel as well.
+#
+# - In kernel-image's preinstall scriptlet, it backs up original kernel to avoid
+#   probable confliction with the new one.
+#
+# - In kernel-image's postinstall scriptlet, it modifies grub's config file to
+#   updates the new kernel as the boot priority.
+#
+
+pkg_preinst_kernel-image_append () {
+        # Parsing confliction
+        [ -f "$D/boot/grub/menu.list" ] && grubcfg="$D/boot/grub/menu.list"
+        [ -f "$D/boot/grub/grub.cfg" ] && grubcfg="$D/boot/grub/grub.cfg"
+        if [ -n "$grubcfg" ]; then
+                # Dereference symlink to avoid confliction with new kernel name.
+                if grep -q "/${KERNEL_IMAGETYPE} \+root=" $grubcfg; then
+                        if [ -L "$D/boot/${KERNEL_IMAGETYPE}" ]; then
+                                kimage=`realpath $D/boot/${KERNEL_IMAGETYPE} 2>/dev/null`
+                                if [ -f "$D$kimage" ]; then
+                                        sed -i "s:${KERNEL_IMAGETYPE} \+root=:${kimage##*/} root=:" $grubcfg
+                                fi
+                        fi
+                fi
+
+                # Rename old kernel if it conflicts with new kernel name.
+                if grep -q "/${KERNEL_IMAGETYPE}-${KERNEL_VERSION} \+root=" $grubcfg; then
+                        if [ -f "$D/boot/${KERNEL_IMAGETYPE}-${KERNEL_VERSION}" ]; then
+                                timestamp=`date +%s`
+                                kimage="$D/boot/${KERNEL_IMAGETYPE}-${KERNEL_VERSION}-$timestamp-back"
+                                sed -i "s:${KERNEL_IMAGETYPE}-${KERNEL_VERSION} \+root=:${kimage##*/} root=:" $grubcfg
+                                mv "$D/boot/${KERNEL_IMAGETYPE}-${KERNEL_VERSION}" "$kimage"
+                        fi
+                fi
+        fi
+}
+
+pkg_postinst_kernel-image_prepend () {
+        get_new_grub_cfg() {
+                grubcfg="$1"
+                title="Update ${KERNEL_IMAGETYPE}-${KERNEL_VERSION}-${PV}"
+                if [ "${grubcfg##*/}" = "grub.cfg" ]; then
+                        rootfs=`grep " *linux \+[^ ]\+ \+root=" $grubcfg -m 1 | \
+                                 sed "s# *linux \+[^ ]\+ \+root=#    linux /${KERNEL_IMAGETYPE}-${KERNEL_VERSION} root=#"`
+
+                        echo "menuentry \"$title\" {"
+                        echo "    set root=(hd0,1)"
+                        echo "$rootfs"
+                        echo "}"
+                elif [ "${grubcfg##*/}" = "menu.list" ]; then
+                        rootfs=`grep "kernel \+[^ ]\+ \+root=" $grubcfg -m 1 | \
+                                 sed "s#kernel \+[^ ]\+ \+root=#kernel /${KERNEL_IMAGETYPE}-${KERNEL_VERSION} root=#"`
+
+                        echo "default 0"
+                        echo "timeout 30"
+                        echo "title $title"
+                        echo "root  (hd0,0)"
+                        echo "$rootfs"
+                fi
+        }
+
+        get_old_grub_cfg() {
+                grubcfg="$1"
+                if [ "${grubcfg##*/}" = "grub.cfg" ]; then
+                        cat "$grubcfg"
+                elif [ "${grubcfg##*/}" = "menu.list" ]; then
+                        cat "$grubcfg" | sed -e '/^default/d' -e '/^timeout/d'
+                fi
+        }
+
+        if [ -f "$D/boot/grub/grub.cfg" ]; then
+                grubcfg="$D/boot/grub/grub.cfg"
+                old_image=`grep ' *linux \+[^ ]\+ \+root=' -m 1 "$grubcfg" | awk '{print $2}'`
+        elif [ -f "$D/boot/grub/menu.list" ]; then
+                grubcfg="$D/boot/grub/menu.list"
+                old_image=`grep '^kernel \+[^ ]\+ \+root=' -m 1 "$grubcfg" | awk '{print $2}'`
+        fi
+
+        # Don't update grubcfg at first install while old bzImage doesn't exist.
+        if [ -f "$D/boot/$old_image" ]; then
+                grubcfgtmp="$grubcfg.tmp"
+                get_new_grub_cfg "$grubcfg"  > $grubcfgtmp
+                get_old_grub_cfg "$grubcfg" >> $grubcfgtmp
+                mv $grubcfgtmp $grubcfg
+                echo "Caution! Update kernel may affect kernel-module!"
+        fi
+}
+