Optional features allow distros to define sets of transfers that can
be enabled or disabled by the system administrator. This is useful for
situations where a distro may want to ship some resources version-locked
to the core OS, but many people have no need for the resource, such as:
development tools/compilers, drivers for specialized hardware, language
packs, etc
We also rename sysupdate.d/*.conf -> sysupdate.d/*.transfer, because
now there are more than one type of definition in sysupdate.d/. For
backwards compat, we still load *.conf files as long as no *.transfer
files are found and the *.conf files don't try to declare themselves
as part of any features
Fixes https://github.com/systemd/systemd/issues/33343
Fixes https://github.com/systemd/systemd/issues/33344
In mkosi, I want to add a sysupdate verb to wrap systemd-sysupdate.
The definitions will be picked up from mkosi.sysupdate/ and passed
to systemd-sysupdate. I want users to be able to write transfer
definitions that are independent of the output directory used by
mkosi. To make this possible, it should be possible to specify the
directory that transfer sources should be looked up in on the sysupdate
command line. Let's allow this via a new --transfer-source= option.
Additionally, transfer sources that want to take advantage of this
feature should specify PathRelativeTo=directory to indicate the configured
Path= is interpreted relative to the tranfer source directory specified
on the CLI.
This allows for the following transfer definition to be put in
mkosi.sysupdate:
"""
[Transfer]
ProtectVersion=%A
[Source]
Type=regular-file
Path=/
PathRelativeTo=directory
MatchPattern=ParticleOS_@v.usr-%a.@u.raw
[Target]
Type=partition
Path=auto
MatchPattern=ParticleOS_@v
MatchPartitionType=usr
PartitionFlags=0
ReadOnly=1
"""
We set up a NOTIFY_SOCKET to get download progress notifications from
each individual import helper. Along with the number of import jobs we
have to run, this gives an overall progress value which we report using
sd_notify