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docs: document the new environment variables logind groks

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Lennart Poettering 2018-10-23 15:53:18 +02:00
parent 350f9518ac
commit e86c7a3abc
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docs/ENVIRONMENT.md
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@ -107,6 +107,51 @@ systemd-udevd:
with `:` in which case the kernel command line option takes precedence, if it
is specified as well.
* `$SYSTEMD_REBOOT_TO_FIRMWARE_SETUP` — if set overrides systemd-logind's
built-in EFI logic of requesting a reboot into the firmware. Takes a
boolean. If set to false the functionality is turned off entirely. If set to
true instead of requesting a reboot into the firmware setup UI through EFI a
file `/run/systemd/reboot-to-firmware-setup` is created whenever this is
requested. This file may be checked for by services run during system
shutdown in order to request the appropriate operation from the firmware in
an alternative fashion.
* `$SYSTEMD_REBOOT_TO_BOOT_LOADER_MENU` — similar to the above, allows
overriding of systemd-logind's built-in EFI logic of requesting a reboot into
the boot loader menu. Takes a boolean. If set to false the functionality is
turned off entirely. If set to true instead of requesting a reboot into the
boot loader menu through EFI a file `/run/systemd/reboot-to-boot-loader-menu`
is created whenever this is requested. The file contains the requested boot
loader menu timeout in µs, formatted in ASCII decimals, or zero in case no
time-out is requested. This file may be checked for by services run during
system shutdown in order to request the appropriate operation from the boot
loader in an alternative fashion.
* `$SYSTEMD_REBOOT_TO_BOOT_LOADER_ENTRY` — similar to the above, allows
overriding of systemd-logind's built-in EFI logic of requesting a reboot into
a specific boot loader entry. Takes a boolean. If set to false the
functionality is turned off entirely. If set to true instead of requesting a
reboot into a specific boot loader entry through EFI a file
`/run/systemd/reboot-to-boot-loader-entry` is created whenever this is
requested. The file contains the requested boot loader entry identifier. This
file may be checked for by services run during system shutdown in order to
request the appropriate operation from the boot loader in an alternative
fashion. Note that by default only boot loader entries which follow the [Boot
Loader Specification](https://systemd.io/BOOT_LOADER_SPECIFICATION) and are
placed in the ESP or the Extended Boot Loader partition may be selected this
way. However, if a directory `/run/boot-loader-entries/` exists, the entries
are loaded from there instead. The directory should contain the usual
directory hierarchy mandated by the Boot Loader Specification, i.e. the entry
drop-ins should be placed in
`/run/boot-loader-entries/loader/entries/*.conf`, and the files referenced by
the drop-ins (including the kernels and initrds) somewhere else below
`/run/boot-loader-entries/`. Note that all these files may be (and are
supposed to be) symlinks. systemd-logind will load these files on-demand,
these files can hence be updated (ideally atomically) whenever the boot
loader configuration changes. A foreign boot loader installer script should
hence synthesize drop-in snippets and symlinks for all boot entries at boot
or whenever they change if it wants to integrate with systemd-logind's APIs.
installed systemd tests:
* `$SYSTEMD_TEST_DATA` — override the location of test data. This is useful if