x86: preserve partition table on sysupgrade

[openwrt.git] / target / linux / x86 / base-files / lib / upgrade / platform.sh

diff --git a/target/linux/x86/base-files/lib/upgrade/platform.sh b/target/linux/x86/base-files/lib/upgrade/platform.sh
index 73ab5ef..86696ae 100644 (file)
--- a/target/linux/x86/base-files/lib/upgrade/platform.sh
+++ b/target/linux/x86/base-files/lib/upgrade/platform.sh
@@ -55,12 +55,59 @@ platform_copy_config() {
        fi
 }
 
+get_partitions() { # <device> <filename>
+       local disk="$1"
+       local filename="$2"
+
+       if [ -b "$disk" -o -f "$disk" ]; then
+               echo "Reading partition table from $filename..."
+               partx -r "$disk" -gbo NR,START,SECTORS > "/tmp/partx.$filename"
+       fi
+}
+
 platform_do_upgrade() {
        platform_export_bootpart
+       disk="${BOOTPART%[0-9]}"
 
-       if [ -b "${BOOTPART%[0-9]}" ]; then
+       if [ -b "$disk" ]; then
                sync
-               get_image "$@" | dd of="${BOOTPART%[0-9]}" bs=4096 conv=fsync
+               if [ "$SAVE_PARTITIONS" = "1" ]; then
+                       get_partitions "$disk" bootdisk
+
+
+                       #get block size
+                       sectors="$(partx -r $disk -gbo SECTORS --nr 1:1)"
+                       size="$(partx -r $disk -gbo SIZE --nr 1:1)"
+                       ibs="$(($size / $sectors))"
+
+                       #extract the boot sector from the image
+                       get_image "$@" | dd of=/tmp/image.bs count=1 bs=512b
+
+                       get_partitions /tmp/image.bs image
+
+                       #compare tables
+                       diff="$(grep -F -x -v -f /tmp/partx.bootdisk /tmp/partx.image)"
+                       if [ -n "$diff" ]; then
+                               echo "Partition layout is changed.  Full image will be written."
+                               ask_bool 0 "Abort" && exit
+
+                               get_image "$@" | dd of="$disk" bs=4096 conv=fsync
+                               return 0
+                       fi
+
+                       #iterate over each partition from the image and write it to the boot disk
+                       while read part start size; do
+                       echo "Writing image to $disk$part..."
+                               get_image "$@" | dd of="$disk$part" ibs="$ibs" obs=1M skip="$start" count="$size" conv=fsync
+                       done < /tmp/partx.image
+
+                       #copy partition uuid
+                       echo "Writing new UUID to $disk$part..."
+                       get_image "$@" | dd of="$disk" bs=1 skip=440 count=4 seek=440 conv=fsync
+               else
+                       get_image "$@" | dd of="$disk" bs=4096 conv=fsync
+               fi
+
                sleep 1
        fi
 }