7c03445fb7
When systemd is started, it sets the system clock to epoch to ensure the
system clock is reasonably initialized if no working RTC.
As init process, systemd sets epoch very early to the more recent
timestamp of[1]:
- the build time of systemd (-Dtime-epoch)
- the modification time ("mtime") of /var/lib/systemd/timesync/clock
(systemd-timesyncd)
- the modification time ("mtime") of /usr/lib/clock-epoch (systemd)
The first epoch timestamp is hard-coded at build-time by the systemd
recipe (using either SOURCE_DATE_EPOCH, git-tag, or NEWS modification
time[2]).
The second epoch timestamp is maintained at run-time if the system runs
systemd-timesyncd.
This implements the third epoch timestamp at image build-time, by
touching the timestamp file /usr/lib/clock-epoch from the package
post-install script.
[1]: 863098fdc9
[2]: https://github.com/systemd/systemd/blob/v256/meson.build#L804-L825
(From OE-Core rev: 0f51fee4a5408c17cbaf827053f13d6c3b9dbc2c)
Signed-off-by: Gaël PORTAY <gael.portay+rtone@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Poky
Poky is an integration of various components to form a pre-packaged build system and development environment which is used as a development and validation tool by the Yocto Project. It features support for building customised embedded style device images and custom containers. There are reference demo images ranging from X11/GTK+ to Weston, commandline and more. The system supports cross-architecture application development using QEMU emulation and a standalone toolchain and SDK suitable for IDE integration.
Additional information on the specifics of hardware that Poky supports is available in README.hardware. Further hardware support can easily be added in the form of BSP layers which extend the systems capabilities in a modular way. Many layers are available and can be found through the layer index.
As an integration layer Poky consists of several upstream projects such as BitBake, OpenEmbedded-Core, Yocto documentation, the 'meta-yocto' layer which has configuration and hardware support components. These components are all part of the Yocto Project and OpenEmbedded ecosystems.
The Yocto Project has extensive documentation about the system including a reference manual which can be found at https://docs.yoctoproject.org/
OpenEmbedded is the build architecture used by Poky and the Yocto project. For information about OpenEmbedded, see the OpenEmbedded website.
Contribution Guidelines
Please refer to our contributor guide here: https://docs.yoctoproject.org/dev/contributor-guide/ for full details on how to submit changes.
Where to Send Patches
As Poky is an integration repository (built using a tool called combo-layer), patches against the various components should be sent to their respective upstreams:
OpenEmbedded-Core (files in meta/, meta-selftest/, meta-skeleton/, scripts/):
- Git repository: https://git.openembedded.org/openembedded-core/
- Mailing list: openembedded-core@lists.openembedded.org
BitBake (files in bitbake/):
- Git repository: https://git.openembedded.org/bitbake/
- Mailing list: bitbake-devel@lists.openembedded.org
Documentation (files in documentation/):
- Git repository: https://git.yoctoproject.org/cgit/cgit.cgi/yocto-docs/
- Mailing list: docs@lists.yoctoproject.org
meta-yocto (files in meta-poky/, meta-yocto-bsp/):
- Git repository: https://git.yoctoproject.org/cgit/cgit.cgi/meta-yocto
- Mailing list: poky@lists.yoctoproject.org
If in doubt, check the openembedded-core git repository for the content you intend to modify as most files are from there unless clearly one of the above categories. Before sending, be sure the patches apply cleanly to the current git repository branch in question.