Refactor code to select boot kernel

The script to find best kernel from image (used by vm
and baremetal element) is duplicated and is not in sync
with each other. Moving the code to img-functions as a
function will reduce duplicated code and make it reusable
in future.

Since img-functions is not accessible in chroot env,
kernel selection is being moved from finalise.d to
cleanup.d in the vm element.

Change-Id: I8fbccc13a2c61a5191ef9ea5d2a8302a3e43b000

bin/disk-image-get-kernel

@@ -81,41 +81,7 @@ ensure_nbd
 # sets WORK_DIR
 mount_qcow_image $IMAGE_FILE
 
-# Dig up the initrd and kernel to use.
+select_boot_kernel_initrd $WORK_DIR
-BOOTDIR="$WORK_DIR/boot"
-KERNEL=
-RAMDISK=
-if [ -f $WORK_DIR/etc/redhat-release ]; then
-
-    # Prioritize PAE if present
-    KERNEL=$(ls -1rv $BOOTDIR/vmlinuz*  | grep PAE | grep -v debug | head -1)
-    if [ ! $KERNEL ]; then
-        KERNEL=$(ls -1rv $BOOTDIR/vmlinuz* | grep -v debug | head -1)
-        if [ ! $KERNEL ]; then
-            echo "No suitable kernel found."
-            exit 1
-        fi
-    fi
-
-    KERNEL=$(basename $KERNEL)
-    KERNEL_VERSION=`echo $KERNEL | sed 's/vmlinuz-//g'`
-
-    RAMDISK=$(basename `ls $BOOTDIR/initramfs-$KERNEL_VERSION.img`)
-    if [ ! $RAMDISK ]; then
-        echo "Can't find an initramfs for the $KERNEL_VERSION version of the kernel."
-        exit 1
-    fi
-
-elif [ -f $WORK_DIR/etc/debian_version ]; then
-    KERNEL=$(basename `ls -1rv $BOOTDIR/vmlinuz*generic | head -1`)
-    RAMDISK=$(basename `ls -1rv $BOOTDIR/initrd*generic | head -1`)
-elif [ -f $WORK_DIR/etc/SuSE-release ]; then
-    KERNEL=$(basename `ls -1rv $BOOTDIR/vmlinuz`)
-    RAMDISK=$(basename `ls -1rv $BOOTDIR/initrd`)
-else
-    echo "ERROR: Unable to detect operating system"
-    exit 1
-fi
 
 sudo cp $BOOTDIR/$KERNEL $OUT_DIR/$OUT_PFX-vmlinuz
 sudo cp $BOOTDIR/$RAMDISK $OUT_DIR/$OUT_PFX-initrd

elements/baremetal/cleanup.d/99-extract-kernel-and-ramdisk

@@ -19,45 +19,10 @@ set -o pipefail
 
 [ -n "$TARGET_ROOT" ]
 
+source $_LIB/img-functions
+
 # Dig up the initrd and kernel to use.
-BOOTDIR="$TARGET_ROOT/boot"
+select_boot_kernel_initrd $TARGET_ROOT
-KERNEL=
-RAMDISK=
-if [ -n "${DIB_BAREMETAL_KERNEL_PATTERN:-}" -a -n "${DIB_BAREMETAL_INITRD_PATTERN:-}" ]; then
-    KERNEL=$(basename `eval ls -1rv "$BOOTDIR/${DIB_BAREMETAL_KERNEL_PATTERN}" | head -1`)
-    RAMDISK=$(basename `eval ls -1rv "$BOOTDIR/${DIB_BAREMETAL_INITRD_PATTERN}" | head -1`)
-elif [ -f $TARGET_ROOT/etc/redhat-release ]; then
-
-    # Prioritize PAE if present
-    KERNEL=$(ls -1rv $BOOTDIR/vmlinuz*  | grep PAE | grep -v debug | head -1 || echo "")
-    if [ ! $KERNEL ]; then
-        KERNEL=$(ls -1rv $BOOTDIR/vmlinuz* | grep -v debug | head -1 || echo "")
-        if [ ! $KERNEL ]; then
-            echo "No suitable kernel found."
-            exit 1
-        fi
-    fi
-
-    KERNEL=$(basename $KERNEL)
-    KERNEL_VERSION=`echo $KERNEL | sed 's/vmlinuz-//g'`
-
-    RAMDISK=$(basename `ls $BOOTDIR/initramfs-$KERNEL_VERSION.img` || echo "")
-    if [ ! $RAMDISK ]; then
-        echo "Can't find an initramfs for the $KERNEL_VERSION version of the kernel."
-        exit 1
-    fi
-
-elif [ -f $TARGET_ROOT/etc/debian_version ]; then
-    KERNEL=$(basename `ls -1rv $BOOTDIR/vmlinuz*generic | head -1`)
-    RAMDISK=$(basename `ls -1rv $BOOTDIR/initrd*generic | head -1`)
-elif [ -f $TARGET_ROOT/etc/SuSE-release ]; then
-    KERNEL=vmlinuz
-    RAMDISK=initrd
-else
-    echo "ERROR: Unable to detect operating system"
-    exit 1
-fi
-
 sudo cp $BOOTDIR/$KERNEL ${IMAGE_NAME}.vmlinuz
 sudo cp $BOOTDIR/$RAMDISK ${IMAGE_NAME}.initrd
 sudo chmod a+r ${IMAGE_NAME}.vmlinuz

elements/vm/cleanup.d/51-bootloader

@@ -0,0 +1,37 @@
+#!/bin/bash
+#
+# Copyright 2014 Hewlett-Packard Development Company, L.P.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+set -eux
+set -o pipefail
+
+[ -n "$TARGET_ROOT" ]
+
+source $_LIB/img-functions
+
+# Dig up the initrd and kernel to use.
+if [ -d $TARGET_ROOT/boot/syslinux ] ; then
+    select_boot_kernel_initrd $TARGET_ROOT
+
+    cat > $TARGET_ROOT/boot/syslinux/syslinux.cfg<<_EOF_
+DEFAULT linux
+
+LABEL linux
+    KERNEL $KERNEL
+    APPEND ro root=LABEL=cloudimg-rootfs console=tty0 console=ttyS0,115200
+    INITRD $RAMDISK
+_EOF_
+fi

elements/vm/finalise.d/51-bootloader

@@ -29,33 +29,6 @@ function install_extlinux {
 
     mkdir -p /boot/syslinux
     extlinux --install /boot/syslinux
-
-    if [ -f /etc/redhat-release ]; then
-        kernel=$(ls -1rv /boot/vmlinuz* | head -1)
-        initrd=$(ls -1rv /boot/initramfs* | head -1)
-    elif [ -f /etc/SuSE-release ]; then
-        kernel=$(ls -1rv /boot/vmlinuz* | head -1)
-        initrd=$(ls -1rv /boot/initrd* | head -1)
-    elif [ -f /etc/debian_version ]; then
-        kernel=$(ls -1rv /boot/vmlinuz*generic | head -1)
-        initrd=$(ls -1rv /boot/initrd*generic | head -1)
-
-        # in case files with "generic" suffix were not found, fall back to default
-        kernel=${kernel:-$(ls -1rv /boot/vmlinuz* | head -1)}
-        initrd=${initrd:-$(ls -1rv /boot/initrd* | head -1)}
-    else
-        echo "Unable to find kernel and initram"
-        exit 1
-    fi
-
-    cat > /boot/syslinux/syslinux.cfg<<_EOF_
-DEFAULT linux
-
-LABEL linux
-    KERNEL $kernel
-    APPEND ro root=LABEL=cloudimg-rootfs console=tty0 console=ttyS0,115200
-    INITRD  $initrd
-_EOF_
 }
 
 function install_grub2 {

lib/img-functions

@@ -127,3 +127,42 @@ function copy_elements_lib () {
   sudo mkdir -p $TMP_MOUNT_PATH/lib/diskimage-builder
   sudo cp -t $TMP_MOUNT_PATH/lib/diskimage-builder $_LIB/elements-functions
 }
+
+# Dig up the initrd and kernel.
+function select_boot_kernel_initrd () {
+    TARGET_ROOT=$1
+    BOOTDIR=$TARGET_ROOT/boot
+    if [ -n "${DIB_BAREMETAL_KERNEL_PATTERN:-}" -a -n "${DIB_BAREMETAL_INITRD_PATTERN:-}" ]; then
+        KERNEL=$(basename `eval ls -1rv "$BOOTDIR/${DIB_BAREMETAL_KERNEL_PATTERN}" | head -1`)
+        RAMDISK=$(basename `eval ls -1rv "$BOOTDIR/${DIB_BAREMETAL_INITRD_PATTERN}" | head -1`)
+    elif [ -f $TARGET_ROOT/etc/redhat-release ]; then
+
+        # Prioritize PAE if present
+        KERNEL=$(ls -1rv $BOOTDIR/vmlinuz* | grep PAE | grep -v debug | head -1 || echo "")
+        KERNEL=${KERNEL:-$(ls -1rv $BOOTDIR/vmlinuz* | grep -v debug | head -1 || echo "")}
+        if [ ! $KERNEL ]; then
+           echo "No suitable kernel found."
+           exit 1
+        fi
+
+        KERNEL=$(basename $KERNEL)
+        KERNEL_VERSION=${KERNEL#vmlinuz-}
+        RAMDISK=$(basename `ls $BOOTDIR/initramfs-$KERNEL_VERSION.img` || echo "")
+        if [ ! $RAMDISK ]; then
+            echo "Can't find an initramfs for the $KERNEL_VERSION version of the kernel."
+            exit 1
+        fi
+    elif [ -f $TARGET_ROOT/etc/debian_version ]; then
+        KERNEL=$(basename `ls -1rv $BOOTDIR/vmlinuz*generic | head -1`)
+        RAMDISK=$(basename `ls -1rv $BOOTDIR/initrd*generic | head -1`)
+        # in case files with "generic" suffix were not found, fall back to default
+        KERNEL=${KERNEL:-$(basename `ls -1rv $BOOTDIR/vmlinuz* | head -1`)}
+        RAMDISK=${RAMDISK:-$(basename `ls -1rv $BOOTDIR/initrd* | head -1`)}
+    elif [ -f $TARGET_ROOT/etc/SuSE-release ]; then
+        KERNEL=vmlinuz
+        RAMDISK=initrd
+    else
+        echo "ERROR: Unable to detect operating system"
+        exit 1
+    fi
+}