sdcard_image-rpi: Add 1st cut at a class to build an SD card image for the RPi.

1 files changed, 131 insertions, 0 deletions

diff --git a/classes/sdcard_image-rpi.bbclass b/classes/sdcard_image-rpi.bbclass
new file mode 100644
index 0000000..1ac3e84
--- /dev/null
+++ b/classes/sdcard_image-rpi.bbclass
@@ -0,0 +1,131 @@
+inherit image
+
+# Add the fstypes we need
+IMAGE_FSTYPES_append = " tar.bz2 rpi-sdimg"
+
+# Ensure required utilities are present
+IMAGE_DEPENDS_rpi-sdimg = "genext2fs-native e2fsprogs-native bcm2835-bootfiles bcm2835-kernel-image"
+
+# Register this as an avalable type of image.
+IMAGE_TYPES_append = " rpi-sdimg"
+
+# Change this to match your host distro
+LOSETUP ?= "/sbin/losetup"
+
+# Since these need to go in /etc/fstab we can hardcode them
+# Since the vars are weakly assigned, you can override them from your local.conf
+LOOPDEV ?= "/dev/loop1"
+LOOPDEV_BOOT ?= "/dev/loop2"
+LOOPDEV_FS ?= "/dev/loop3"
+
+# Default to 4GiB images
+SDIMG_SIZE ?= "444" 
+
+# FS type for rootfs
+ROOTFSTYPE ?= "ext4"
+
+BOOTPARTNAME ?= "${MACHINE}"
+
+IMAGEDATESTAMP = "${@time.strftime('%Y.%m.%d',time.gmtime())}"
+
+# Additional files and/or directories to be copied into the vfat partition from the IMAGE_ROOTFS.
+FATPAYLOAD ?= ""
+
+IMAGE_CMD_rpi-sdimg () {
+        SDIMG=${WORKDIR}/sd.img
+
+        # sanity check fstab entry for boot partition mounting
+        if [ "x$(cat /etc/fstab | grep ${LOOPDEV_BOOT} | grep ${WORKDIR}/tmp-mnt-boot | grep user || true)" = "x" ]; then
+                echo "/etc/fstab entries need to be created with the user flag for the loop devices like:"
+                echo "${LOOPDEV_BOOT} ${WORKDIR}/tmp-mnt-boot vfat user 0 0"
+        false
+        fi
+
+        # cleanup loops
+        for loop in ${LOOPDEV} ${LOOPDEV_BOOT} ${LOOPDEV_FS} ; do
+                ${LOSETUP} -d $loop || true
+        done
+
+        # If an SD image is already present, reuse and reformat it
+        if [ ! -e ${SDIMG} ] ; then
+                dd if=/dev/zero of=${SDIMG} bs=$(echo '255 * 63 * 512' | bc) count=${SDIMG_SIZE}
+        fi
+
+        ${LOSETUP} ${LOOPDEV} ${SDIMG}
+
+        # Create partition table
+        dd if=/dev/zero of=${LOOPDEV} bs=1024 count=1024
+        SIZE=$(/sbin/fdisk -l ${LOOPDEV} | grep Disk | grep bytes | awk '{print $5}')
+        CYLINDERS=$(echo $SIZE/255/63/512 | bc)
+        {
+        echo ,9,0x0C,*
+        echo ,,,-
+        } | /sbin/sfdisk -D -H 255 -S 63 -C ${CYLINDERS} ${LOOPDEV}
+
+        # Prepare loop devices for boot and filesystem partitions
+        BOOT_OFFSET=32256
+        FS_OFFSET_SECT=$(/sbin/fdisk -l -u ${LOOPDEV} 2>&1 | grep Linux | perl -p -i -e "s/\s+/ /"|cut -d " " -f 2)
+        FS_OFFSET=$(echo "$FS_OFFSET_SECT * 512" | bc)
+        FS_SIZE_BLOCKS=$(/sbin/fdisk -l -u ${LOOPDEV} 2>&1 | grep Linux | perl -p -i -e "s/\s+/ /g" \ 
+        |cut -d " " -f 4 | cut -d "+" -f 1)
+ 
+        LOOPDEV_BLOCKS=$(/sbin/fdisk -l -u ${LOOPDEV} 2>&1 | grep FAT | perl -p -i -e "s/\s+/ /g"|cut -d " " -f 5)
+        LOOPDEV_BYTES=$(echo "$LOOPDEV_BLOCKS * 1024" | bc)
+
+        ${LOSETUP} -d ${LOOPDEV}
+
+        ${LOSETUP} ${LOOPDEV_BOOT} ${SDIMG} -o ${BOOT_OFFSET} 
+
+        /sbin/mkfs.vfat ${LOOPDEV_BOOT} -n ${BOOTPARTNAME} $LOOPDEV_BLOCKS
+
+        # Prepare boot partion. First mount the boot partition, and copy the bootloader and supporting files.
+
+        mkdir -p ${WORKDIR}/tmp-mnt-boot
+        mount $LOOPDEV_BOOT ${WORKDIR}/tmp-mnt-boot
+
+        echo "Copying bootloader and prepended kernel.img into the boot partition"
+        cp -v ${DEPLOY_DIR_IMAGE}/bcm2835-bootfiles/* ${WORKDIR}/tmp-mnt-boot || true
+
+        if [ -n ${FATPAYLOAD} ] ; then
+                echo "Copying payload into VFAT"
+                for entry in ${FATPAYLOAD} ; do
+                                # add the || true to stop aborting on vfat issues like not supporting .~lock files
+                                cp -av ${IMAGE_ROOTFS}$entry ${WORKDIR}/tmp-mnt-boot || true
+                done
+        fi
+
+        echo "${IMAGE_NAME}-${IMAGEDATESTAMP}" > ${IMAGE_ROOTFS}/etc/image-version-info
+        
+        cp -v ${IMAGE_ROOTFS}/etc/image-version-info ${WORKDIR}/tmp-mnt-boot || true
+
+        # Cleanup VFAT mount
+        echo "Cleaning up VFAT mount"
+        umount ${WORKDIR}/tmp-mnt-boot
+        ${LOSETUP} -d ${LOOPDEV_BOOT} || true
+
+        # Prepare rootfs parition
+        echo "Creating rootfs loopback"
+        ${LOSETUP} ${LOOPDEV_FS} ${SDIMG} -o ${FS_OFFSET}
+
+        FS_NUM_INODES=$(echo $FS_SIZE_BLOCKS / 4 | bc)
+
+        case "${ROOTFSTYPE}" in
+                ext3)
+                                genext2fs -z -N $FS_NUM_INODES -b $FS_SIZE_BLOCKS -d ${IMAGE_ROOTFS} ${LOOPDEV_FS}
+                                tune2fs -L ${IMAGE_NAME} -j ${LOOPDEV_FS}
+                                ;;
+                ext4)
+                                genext2fs -z -N $FS_NUM_INODES -b $FS_SIZE_BLOCKS -d ${IMAGE_ROOTFS} ${LOOPDEV_FS}
+                                tune2fs -L ${IMAGE_NAME} -j -O extents,uninit_bg,dir_index ${LOOPDEV_FS}
+                                ;;
+                *)
+                                echo "Please set ROOTFSTYPE to something supported"
+                                exit 1
+                                ;;
+        esac
+
+        ${LOSETUP} -d ${LOOPDEV_FS} || true
+
+        gzip -c ${WORKDIR}/sd.img > ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}-${IMAGEDATESTAMP}.img.gz
+        rm -f ${WORKDIR}/sd.img
+}