OpenWRT Build System for CentOS 7
Revision as of 12:55, 7 September 2020 by Root (talk | contribs) (→Obtain Source Files from OpenWRT)
How does one create a "build system" (AKA Cross Compile / Cross-Compile / CrossCompile Build System) for OpenWRT?
Other Tutorials
- General Guide for building firmware: https://openwrt.org/docs/guide-user/additional-software/beginners-build-guide
- Start of detailed Information: https://openwrt.org/docs/guide-developer/build-system/start
- Pre-requisites for a : https://openwrt.org/docs/guide-developer/build-system/install-buildsystem
- Some additional granular detail for working with specific versions: https://openwrt.org/docs/guide-developer/build-system/use-buildsystem
- Build environment tips: https://openwrt.org/docs/guide-developer/env
- SDK (for compiling specific packages): https://openwrt.org/docs/guide-developer/using_the_sdk
- URL for SDK (look towards the bottom of the page for SDK): https://downloads.openwrt.org/releases/19.07.3/targets/mvebu/cortexa9/
- Third Party Site with nice information (Old, but this article itself notes even older OpenWRT documentation): http://www.acme-dot.com/building-openwrt-14-07-barrier-breaker-on-ubuntu-and-os-x/ (Don't follow the instructions as it GIT won't work anymore with non-SSL URLs)
- Entware Tips (The don't apply directly, but have some good tips if read from the context of OpenWRT)
- Native Compilation: https://github.com/Entware/Entware-ng/wiki/Using-gcc-%28native-compilation%29
- Compiling Packages from Source: https://github.com/Entware/Entware-ng/wiki/Compile-packages-from-sources
- Creating Perl modules: https://github.com/Entware/Entware-ng/wiki/Self-installation-of-perl-modules
Environment
- Build System for Cross-Compiling: CentOS 7.8 (There seem to be some missing packages in CentOS 8, so CentOS 7.8 was chosen)
- OpenWRT 19.07.03 (Linux Kernel 4.14.180)
- Linksys WRT3200ACM Platform Information (see here for additional information)
- Marvell Armada 385 88F6820 SoS (System on a Chip)
- Manufacturer: Marvell, MVEBU (Marvell Embedded Business Unit)
- CPU Information
- ARM Family: Cortex-A (32-bit)
- ARM Architecture: ARMv7-A
- ARM Core: Cortex-A9
- OpenWRT Target and Package Details
- MVEBU (Marvell Embedded Business Unit)
- Targets Available: cortexa53, cortexa72, cortexa9
- Marvell Armada 37x/38x/XP (Armada 3700LP and Armada 7k/8k are 64 bit versions)
- MVEBU (Marvell Embedded Business Unit)
- Equivalent DD-WRT / Entware Target and Package reference
- ARMv7sf-k3.2: ARM version 7 with linux kernel 3.2
- Sources:
Steps (as of 9.2020 for the above Environment)
All of the below assumes one is storing files in the user's home directory.
OpenWRT recommends NOT compiling as a root users. To bypass this restriction;
- export FORCE_UNSAFE_CONFIGURE=1 (the export command adds the variable to the current user session, it will not persist if logging off, confirm with printenv or export -p)
Obtain Source Files from OpenWRT
- git clone -b openwrt-19.07 https://github.com/openwrt/openwrt.git (downloads the 19.07 branch of OpenWRT, which also includes the latest version, 19.07.03)
- To see repository, in web browser: https://git.openwrt.org/openwrt/
- git tag (essentially shows available versions to build)
- git branch (shows local versions of OpenWRT downloaded)
- git branch -r (shows versions available for download)
- Feeds
- Documentation: https://openwrt.org/docs/guide-developer/feeds
- ~/openwrt/feeds.conf.default
- ./scripts/feeds update -a (A script from OpenWRT to makes sure all files are up to date)
- ./scripts/feeds (by itself, no "sub-commands", shows available options)
- ./scripts/feeds list -n (shows main categories of feeds)
- Should show these Names: packages, luci, routing, and telephony
- ./scripts/feeds list -r OneOfTheFeedNames (shows the available packages, names are equivalent to what would be found with opkg list)
- Example: ./scripts/feeds install htop (an enhanced version of top)
- Files will be downloaded here: ~/openwrt/package/feeds/packages/, which are symbolic links to: ~/openwrt/feeds/packages/admin
- Checkout (not needed if a single branch like 19.07 is downloaded)
- git checkout openwrt-19.07 (if multiple branches have been downloaded, switch to using this one)
- Oddly, this command is documented using the latest version of OpenWRT as of 9.2020, but it doesn't work as expected: git checkout v19.07.03 (from https://openwrt.org/docs/guide-developer/build-system/use-buildsystem)
- SDK
- Download the SDK and uncompress it (which is equivalent to the git clone command above)
- URL for SDK (look towards the bottom of the page for SDK): https://downloads.openwrt.org/releases/19.07.3/targets/mvebu/cortexa9/
- Don't worry about the name ending in x86_64 as this indicates the platform that the cross compiling will take place on.
- tar xf WhatEverFileName (be sure one is in the ~ directory)
- ./scripts/feeds update -a
- ./scripts/feeds install WhatEverPackageName
- Download the SDK and uncompress it (which is equivalent to the git clone command above)
- Package Building
- Sources
- Using the HTOP package as an example
- Make a Manifest: https://openwrt.org/docs/guide-developer/helloworld/chapter3 (can copy similar to the below)
- Find a "template" (similar existing package) and copy it: cp -R ~/openwrt/package/feeds/packages/htop ~/openwrt/package/feeds/packages/htopcustom (it's a symbolic link, so cp -R), modify and make changes
- make menuconfig
- PKG_NAME and PKG_VERSION need to change at minimum to get it to show up as a new option
- disable all the Global settings to "build all"
- Utilities (look in the Makefile file in the define Package/tarcustom (or WhatEverName) for where the package will be)
- Headers
- Potential Locations;
- ~/openwrt/build_dir/target-arm_cortex-a9+vfpv3-d16_musl_eabi/linux-mvebu_cortexa9/linux-4.14.195/user_headers/include
- Sources
- Potential Locations;