The chromium build system for Linux will (by default) use a sysroot image rather than building against the libraries installed on the host system. This serves several purposes. Firstly, it ensures that binaries will run on all supported linux systems independent of the packages installed on the build machine. Secondly, it makes the build more hermetic, preventing issues that arise for variations among developers' systems.
The sysroot consists of a minimal installation of Debian/stable (or old-stable) to ensure maximum compatibility. Pre-built sysroot images are stored in Google Cloud Storage and downloaded duringgclient runhooks
Installation of the sysroot is performed bybuild/linux/sysroot_scripts/install-sysroot.py.
This script can be run manually but is normally run as part of gclient hooks. When run from hooks this script in a no-op on non-linux platforms.
The pre-built sysroot images occasionally needs to be rebuilt. For example, when security updates to Debian are released, or when a new package is needed by the chromium build. If you just want to update the sysroots without adding any new packages, skip toUsing build_and_upload.py.
To add a new package, edit thesysroot_creator.py script and modify theDEBIAN_PACKAGES list.
To rebuild the images (without any changes) run the following command for each desired architecture:
$ build/linux/sysroot_scripts/sysroot_creator.py build <arch>
This command on its own should be a no-op and produce an image identical to the one on Google Cloud Storage.
To upload image to Google Cloud Storage run the following command:
$ build/linux/sysroot_scripts/sysroot_creator.py upload <arch>
Here you should use the SHA1 of the git revision at which the images were created.
Uploading new images to Google Clound Storage requires write permission on thechrome-linux-sysroot bucket.
Once new images have been uploaded, thesysroots.json file needs to be updated to reference the new versions. This process is manual and involves updating theRevision andSha1Sum values in the file.
build-and-upload.pyThebuild_and_upload.py script automates the above four steps. It is recommended to use this just before you‘re ready to submit your CL, after you’ve already tested one of the updated sysroots on your local configuration. Build or upload failures will not produce detailed output, but will list the script and arguments that caused the failure. To debug this, you must run the failing command manually. This script requires Google Cloud Storage write permission on thechrome-linux-sysroot bucket.