fea6cf8c09
The systemd ConditionNeedsUpdate option is useful when offline updates
of the vendor operating system resources in /usr require updating of
/etc or /var on the next following boot.
Two examples of services making use of this option are
systemd-hwdb-update.service and systemd-sysusers.service.
ConditionNeedsUpdate=/etc will be true if the mtime of /etc/.updated
is older than the mtime of /usr. After services conditional on
ConditionNeedsUpdate have run, systemd-update-done.service will
synch the mtime of /usr to /etc/.updated so that the condition will
be false on subsequent boots.
For systems with writable /usr partitions where updates are done to
the running system, the update program will touch /usr as a final step.
But with Buildroot, where updates are often done by dumping a new
image onto the device, and where /usr is on a filesystem mounted
read-only, touching /usr as part of the update process is not practical.
Instead, it should be done a build time.
For testers, please note that systemd-update-done in v234 added a
regression where the mtime of /etc/.updated is set to the current time
instead of the mtime or /usr. This will be fixed in v239.
For more details, see:
http://0pointer.de/public/systemd-man/systemd.unit.html
http://0pointer.de/public/systemd-man/systemd-update-done.service.html
Signed-off-by: Chris Lesiak <chris.lesiak@licor.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit
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| boot | ||
| configs | ||
| docs | ||
| fs | ||
| linux | ||
| package | ||
| support | ||
| system | ||
| toolchain | ||
| utils | ||
| .defconfig | ||
| .flake8 | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .gitlab-ci.yml.in | ||
| CHANGES | ||
| Config.in | ||
| Config.in.legacy | ||
| COPYING | ||
| DEVELOPERS | ||
| Makefile | ||
| Makefile.legacy | ||
| README | ||
Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. The documentation can be found in docs/manual. You can generate a text document with 'make manual-text' and read output/docs/manual/manual.text. Online documentation can be found at http://buildroot.org/docs.html To build and use the buildroot stuff, do the following: 1) run 'make menuconfig' 2) select the target architecture and the packages you wish to compile 3) run 'make' 4) wait while it compiles 5) find the kernel, bootloader, root filesystem, etc. in output/images You do not need to be root to build or run buildroot. Have fun! Buildroot comes with a basic configuration for a number of boards. Run 'make list-defconfigs' to view the list of provided configurations. Please feed suggestions, bug reports, insults, and bribes back to the buildroot mailing list: buildroot@buildroot.org You can also find us on #buildroot on Freenode IRC. If you would like to contribute patches, please read https://buildroot.org/manual.html#submitting-patches