append only valid key=value lines for agama.conf

[olafhering]

inst.info=URL allows to retrieve agama settings from a remote location. Usually the expected settings are in key=value format.

This change allows to reuse the inst.info=URL feature for the cobbler "nopxe" API, just like it is done in linuxrc. The system needs to notify cobbler that it booted "far enough", so that cobbler can change the boot loader default from "boot from network" to "boot from local disk". The client has to send a HTTP GET request to the specified URL. cobbler sends the four bytes 'True' in return, which can system has to ignore. Since the content is not and can not be a valid Agama key=value pair, consider only lines that contain '=' in the input file.

Fixes #2185

[kobliha]

There are some options that do not have any value and there might be even more in the future, for example

• live.password_dialog
• live.password_systemd
• Y2DEBUG

See https://agama-project.github.io/docs/user/boot_options and https://agama-project.github.io/docs/user/boot_options/linuxrc_compatibility

[olafhering]

The = for password could be easily enforced, and Y2DEBUG could be specified by kernel cmdline, if really required.

[jreidinger]

question is if we should abuse info param as in past or better have dedicated support in agama with something like agama.cobbler=<URL> that basically do that notification and also verify that it properly return "True" as requested and if not, then report error in agama ( something we plan also for failed of sending info or others ). For me it would be more clear if we do dedicated support with own parameter.

[olafhering]

Well, the client can not do anything about whatever it receives. The point is that it needs to send a GET request, and it needs to deal with any content, by just ignoring it.
There has to be some something=$URL where the received content and every possible error is ignored. And unfortunately nothing like that exists, the new inst.info= option is close to what is required, and in addition there is no dracut upstream to even discuss a generic something=$URL or something=$URL,$outputfile.