A tool that generates custom OpenWRT sysupgrade images
upenwrt is a tool, in form of a (simple) HTTP server, that generates custom
OpenWRT sysupgrade images with all your user-installed packages baked in,
on the fly.
It is designed to aid end-user upgrade process (saving you the hassle of reinstalling all your packages by hand), especially if the target device relies on non-default packages for Internet connectivity.
Assuming that the daemon is reachable at http://upenwrt:8000:
curl http://upenwrt:8000/get | sh > /tmp/sysupgrade.img sysupgrade -v /tmp/sysupgrade.img
Files read by the script:
Command-line arguments and environment variables used by the script:
|Command-line argument||Environment variable||Description||Default|
||enable (more) verbose logging in the script itself||not set|
||do not call the server, only generate the curl(1) command line||not set|
||OpenWRT target name, e. g.
||OpenWRT target name, e. g.
||OpenWRT board name or profile name, e. g.
||current (installed) OpenWRT release, e. g.
||current (installed) OpenWRT revision, e. g.
||list of packages to install into the image, space-separated||overrides
||lists of packages to add/ignore when installing into the image, space-separated||none (supplements
upenwrt is implemented as a (simple) HTTP server daemon that serves a help
/), a script (
/get) and an API endpoint (
The script must be executed on the target device (presumably in the infamous
curl | sh pattern) and will collect user-installed package lists and other
necessary metadata. The API endpoint is supposed to be called by the script
and will return the resulting image in the response body (which will be written
The daemon keeps all of its data in its "root directory", henceforth
$rootdir, the daemon needs:
- a copy of its static file tree under
$rootdir/static(included in upenwrt source tree as
- a copy of OpenWRT git repository under
$rootdir/repo/openwrt.git(bring your own and fetch regularly, upenwrt will not update it)
- an empty cache directory
- an empty work directory
It is advised to put the work directory (
$rootdir/work) on tmpfs and the cache
$rootdir/cache) on a persistent read-write medium with sufficient
storage capacity for a few imagebuilders.
In other words:
mkdir -p /var/lib/upenwrt cp -r root/static -T /var/lib/upenwrt/static mkdir -p /var/lib/upenwrt/repo; git clone --bare https://git.openwrt.org/openwrt/openwrt.git /var/lib/upenwrt/repo/openwrt.git mkdir -p /var/lib/upenwrt/cache mkdir -p /var/lib/upenwrt/work; mount tmpfs -t tmpfs /var/lib/upenwrt/work python -m upenwrt --rootdir /var/lib/upenwrt --baseurl http://upenwrt:8000 --listen '0.0.0.0' --port 8000
The main problem is to separate truly user-installed packages from default
packages (which are marked "user" in the opkg database as well), because while
it is possible to pass all "user" packages to
make image, the default package
set is much more prone to change between revisions than user packages.
The obvious idea would be to compare opkg databases between the squashfs and the overlay. However, this will not work if the user already runs an image with some of their packages baked in (or, by extension, if the tool is used twice or more in a row). The only viable idea known to the author is to get a vanilla openwrt image of a matching revision and use its package list as the base.
However, it is infeasible to download and keep vanilla images corresponding to all possible source revisions (as they are, naturally, rotated daily). Instead, the openwrt source tree is downloaded and cached. Upon each request, the source tree is checked out at the revision matching the pre-existing firmware and targetinfo files are generated by calling the buildsystem. "Vanilla" package lists are then extracted from targetinfo files and subtracted from submitted package lists.
This project is distributed under the terms of the GNU Affero General Public License (AGPL), version 3.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License, version 3 as published by the Free Software Foundation. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.
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