This project adds support for bspatch to the esp32 with some changes: no compression (bz2), no header and changed the interfaces to allow streaming all inputs and outputs.
The functionality in particular can be useful to perform OTA firmware upgrades using compressed diffs between the running firmware and the target firwmare.
At the moment on the esp32 only applying the patch is supported (with the patch generation happening on a computer or anyhow a device with the adequate resources).
Important: esp32_bsdiff is incompatible with the version usually available. Build esp32_bsdiff as described below.
To use with an ESP-IDF project you include this repo in the components directory.
$ cd components
$ git submodule add git@github.com:blockstream/esp32_bsdiff.git esp32_bsdiff
To build bsdiff and bspatch for your computer:
gcc -O2 -DBSDIFF_EXECUTABLE -o esp32_bsdiff components/esp32_bsdiff/bsdiff.c
gcc -O2 -DBSPATCH_EXECUTABLE -o esp32_bspatch components/esp32_bsdiff/bspatch.c
Usage of the command line tools are unchanged from bsdiff.
"usage: %s oldfile newfile patchfile
For bspatch it requires to pass in as a third argument the new file size in bytes shifting the patch filename to forth.
"usage: %s oldfile newfile newsize patchfile
To compress the resulting patch one may use the following (and use miniz.h to decompress on the esp32):
python -c "import zlib; import sys; open(sys.argv[2], 'wb').write(zlib.compress(open(sys.argv[1], 'rb').read(), 9))" uncompress_patch_file.bin compressed_patch_file.bin