Last active
October 13, 2023 00:19
-
-
Save StaticRocket/8934f78b3da7838ca265aa0223e62608 to your computer and use it in GitHub Desktop.
Quickly backup and deploy bootable SD cards with variable size ext4 root partitions
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/bin/sh | |
[ -z "$PART_PREFIX" ] && PART_PREFIX='' | |
DD_ARGS='status=progress conv=fsync' | |
backup() { | |
src="$1" | |
dst="$2" | |
sfdisk -d "${src}" > "${dst}-table.txt" | |
sed -i "$ s/size=[ 0-9]*/size=+/" "${dst}-table.txt" | |
e2image -ra -p "${src}${PART_PREFIX}2" "${dst}-2.img" | |
e2fsck -fp "${dst}-2.img" | |
# catch return codes that mean things were repaired | |
case $? in | |
0) ;; | |
1) ;; | |
2) ;; | |
*) return 1;; | |
esac | |
resize2fs -M -p "${dst}-2.img" | |
dd if="${src}${PART_PREFIX}1" of="${dst}-1.img" ${DD_ARGS} bs=4K | |
} | |
deploy() { | |
src="$1" | |
dst="$2" | |
sfdisk "${dst}" < "${src}-table.txt" | |
e2image -ra -p "${src}-2.img" "${dst}${PART_PREFIX}2" | |
e2fsck -f "${dst}${PART_PREFIX}2" | |
resize2fs -p "${dst}${PART_PREFIX}2" | |
dd if="${src}-1.img" of="${dst}${PART_PREFIX}1" ${DD_ARGS} bs=4K | |
} | |
disk_image() { | |
src="$1" | |
dst="$2" | |
start_sector_list=$( | |
grep -o -P "(?<=start=)\s*\d+" "${src}-table.txt" | tr -d ' ' | |
) | |
first_sector=$(echo "${start_sector_list}" | head -1) | |
last_sector=$(echo "${start_sector_list}" | tail -1) | |
echo "Using ${first_sector} - ${last_sector} as the starting image..." | |
dd if=/dev/zero of="${dst}.img" count="${last_sector}" | |
partition_index=1 | |
for start_sector in ${start_sector_list}; do | |
echo "Copying partition ${partition_index} ..." | |
dd if="${src}-${partition_index}.img" of="${dst}.img" \ | |
seek="${start_sector}" ${DD_ARGS} | |
partition_index=$((partition_index+1)) | |
done | |
sfdisk -w never -f "${dst}.img" < "${src}-table.txt" | |
} | |
help=" | |
[backup/deploy/disk_image] [src] [dst] | |
Example: backup /dev/sdc working-image | |
" | |
if [ $# -eq 3 ]; then | |
case $1 in | |
"backup") | |
backup "$2" "$3";; | |
"deploy") | |
deploy "$2" "$3";; | |
"disk_image") | |
disk_image "$2" "$3";; | |
*) | |
echo "$help" | |
esac | |
else | |
echo "$help" | |
fi |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment