Simple script to test either bsdiff/bspatch of ext4 images, or test that the creation of the ext4 images are deterministic/identical

make_ext4fs-test.sh

#!/bin/bash

git clone git://git.openwrt.org/project/make_ext4fs.git make_ext4fs-git
cd make_ext4fs-git && make && cp make_ext4fs ../
cd ../

dd if=/dev/zero of=testA.ext4 bs=1m count=50
dd if=/dev/zero of=testB.ext4 bs=1m count=50
./make_ext4fs -T 1531952117 -l 50M -b=1M -g=50 testA.ext4
./make_ext4fs -T 1531952117 -l 50M -b=1M -g=50 testB.ext4

echo "pre-mount:"
echo "testA: `shasum testA.ext4`"
echo "testB: `shasum testB.ext4`"

echo "`pwd`"

mkdir tempA/
mkdir tempB/

sudo mount -o loop,noatime -t ext4 testA.ext4 tempA/
sudo mount -o loop,noatime -t ext4 testB.ext4 tempB/

sudo sh -c "echo 'hello' >> tempA/hello"

sudo sh -c "echo 'hello' >> tempB/hello"
sudo sh -c "echo 'world' >> tempB/world"

sudo umount tempA/
sudo umount tempB/

echo "post-mount:"
echo "testA: `shasum testA.ext4`"
echo "testB: `shasum testB.ext4`"

echo "running bsdiff (this may take a while. est 10min)"

bsdiff testA.ext4 testB.ext4 patchC.patch

echo "patch: `shasum patchC.patch`"

echo "running bspatch"

bspatch testA.ext4 testC.ext4 patchC.patch

echo "post-patch:"
echo "testA: `shasum testA.ext4`"
echo "testB: `shasum testB.ext4`"
echo "testC: `shasum testC.ext4`"