Fix optimize_image (fix #87)

Fix a miscalculaton of end of partition parameter for parted. It shall be the
last byte of the partition, not start byte + size. This made parted fail when
the partition wasn't shrunk by resize2fs.

Avoid calling parted if the partition isn't shrunk by resize2fs.

Fix a bug where `cleanup_image.sh` script was not aborting in case of errors,
thus not revealing a corruption of generated image as reported in #87.

Fix a bug where cleanup_image.sh failed using images with more than 10
partitions because of a lazy glob.

Signed-off-by: Paul Guyot <pguyot@kallisys.net>

.github/workflows/test-optimize_image.yml

@@ -28,6 +28,27 @@ jobs:
         gzip /home/actions/temp/optimized-image.img
         imgsize=`stat --printf="%s" /home/actions/temp/optimized-image.img.gz`
         echo "imgsize=${imgsize}" >> $GITHUB_OUTPUT
+  slimmed:
+    runs-on: ubuntu-latest
+    outputs:
+      imgsize: ${{ steps.compress.outputs.imgsize }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: ./ # pguyot/arm-runner-action@HEAD
+      id: slimmed
+      with:
+        base_image: raspios_lite:2021-05-07
+        optimize_image: yes
+        commands: |
+            apt-get -y --purge autoremove ".*python.*"
+            cat /dev/random > /rand || rm /rand
+    - name: Compress image
+      id: compress
+      run: |
+        mv ${{ steps.slimmed.outputs.image }} /home/actions/temp/slimmed-image.img
+        gzip /home/actions/temp/slimmed-image.img
+        imgsize=`stat --printf="%s" /home/actions/temp/slimmed-image.img.gz`
+        echo "imgsize=${imgsize}" >> $GITHUB_OUTPUT
   unoptimized:
     runs-on: ubuntu-latest
     outputs:
@@ -50,10 +71,12 @@ jobs:
         echo "imgsize=${imgsize}" >> $GITHUB_OUTPUT
   compare:
     runs-on: ubuntu-latest
-    needs: [optimized, unoptimized]
+    needs: [optimized, unoptimized, slimmed]
     steps:
     - name: Test image sizes
       run: |
         echo "Optimized size: ${{needs.optimized.outputs.imgsize}}"
+        echo "Slimmed size: ${{needs.slimmed.outputs.imgsize}}"
         echo "Unoptimized size: ${{needs.unoptimized.outputs.imgsize}}"
         test $(( ${{needs.unoptimized.outputs.imgsize}} - ${{needs.optimized.outputs.imgsize}} )) > 300000000
+        test $(( ${{needs.optimized.outputs.imgsize}} - ${{needs.slimmed.outputs.imgsize}} )) > 5000000

cleanup_image.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-set -uo pipefail
+set -euxo pipefail
 
 loopdev=$1
 mount=$2
@@ -12,18 +12,18 @@ rm "${mount}/usr/bin/qemu-arm-static"
 rm "${mount}/usr/bin/qemu-aarch64-static0"
 rm "${mount}/usr/bin/qemu-aarch64-static"
 [ -e "${mount}/etc/_ld.so.preload" ] && mv "${mount}/etc/_ld.so.preload" "${mount}/etc/ld.so.preload"
-mv "${mount}/etc/_resolv.conf" "${mount}/etc/resolv.conf"
+[ -e "${mount}/etc/_resolv.conf" ] && mv "${mount}/etc/_resolv.conf" "${mount}/etc/resolv.conf"
 
 [[ -f "${mount}/tmp/commands.sh" ]] && rm "${mount}/tmp/commands.sh"
 if [[ -d "${mount}" ]]; then
 
     if [[ "${optimize}x" == "x" || "${optimize}x" == "yesx" ]]; then
         if [[ -d "${mount}/boot" ]]; then
             echo "Zero-filling unused blocks on boot filesystem..."
-            cat /dev/zero >"${mount}/boot/zero.fill" 2>/dev/null; sync; rm -f "${mount}/boot/zero.fill"
+            (cat /dev/zero >"${mount}/boot/zero.fill" 2>/dev/null || true); sync; rm -f "${mount}/boot/zero.fill"
         fi
         echo "Zero-filling unused blocks on root filesystem..."
-        cat /dev/zero >"${mount}/zero.fill" 2>/dev/null; sync; rm -f "${mount}/zero.fill"
+        (cat /dev/zero >"${mount}/zero.fill" 2>/dev/null || true); sync; rm -f "${mount}/zero.fill"
     fi
 
     umount "${mount}/dev/pts" || true
@@ -35,7 +35,7 @@ if [[ -d "${mount}" ]]; then
 
     if [[ "${optimize}x" == "x" || "${optimize}x" == "yesx" ]]; then
         rootfs_partnum=${rootpartition}
-        rootdev=$(ls "${loopdev}"*${rootfs_partnum})
+        rootdev="${loopdev}p${rootfs_partnum}"
 
         echo "Resizing root filesystem to minimal size."
         e2fsck -p -f "${rootdev}"
@@ -46,11 +46,16 @@ if [[ -d "${mount}" ]]; then
         echo "Resizing rootfs partition."
         rootfs_partstart=$(parted -m --script "${loopdev}" unit B print | grep "^${rootfs_partnum}:" | awk -F ":" '{print $2}' | tr -d 'B')
         rootfs_partsize=$((${rootfs_blockcount} * ${rootfs_blocksize}))
-        rootfs_partend=$((${rootfs_partstart} + ${rootfs_partsize}))
+        rootfs_partend=$((${rootfs_partstart} + ${rootfs_partsize} - 1))
+        rootfs_partoldend=$(parted -m --script "${loopdev}" unit B print | grep "^${rootfs_partnum}:" | awk -F ":" '{print $3}' | tr -d 'B')
         # parted --script "${loopdev}" unit B resizepart "${rootfs_partnum}" "${rootfs_partend}"
         # Can't use resizepart for shrinking with --script (parted bug#22167) => must rm then mkpart
-        parted --script "${loopdev}" rm "${rootfs_partnum}"
-        parted --script "${loopdev}" unit B mkpart primary "${rootfs_partstart}" "${rootfs_partend}"
+        if [ "$rootfs_partoldend" -gt "$rootfs_partend" ]; then
+            parted --script "${loopdev}" rm "${rootfs_partnum}"
+            parted --script "${loopdev}" unit B mkpart primary "${rootfs_partstart}" "${rootfs_partend}"
+        else
+            echo "Rootfs partition not resized as it was not shrunk"
+        fi
 
         free_space=$(parted -m --script "${loopdev}" unit B print free | tail -1)
         if [[ "${free_space}" =~ "free" ]]; then