The logic is that if the options are updated after boot, we *don't* use
the new value. But we still want to print out the changed contents in
bootctl as to not confuse people.
Fixes#19597.
Also https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=988450.
$ build/bootctl systemd-efi-options
quiet
Note: SystemdOptions EFI variable has been modified since boot. New value: debug
The hint is printed to stderr, so scripts should not be confused.
Creating those string dynamically at runtime is slow and unnecessary.
Let's use static strings with a bit of macro magic and the let the compiler
coalesce as much as possible.
$ size build/src/shared/libsystemd-shared-248.so{.old,}
text data bss dec hex filename
2813453 94572 4584 2912609 2c7161 build/src/shared/libsystemd-shared-248.so.old
2812309 94564 4584 2911457 2c6ce1 build/src/shared/libsystemd-shared-248.so
A nice side-effect is that the same form is used everywhere, so it's easier to
figure out all variables that are used, and where each specific variable is
used.
C.f. 2b0445262a.
Note: 'const char *foo = alloca(…);' seems OK. Our coding style document and
alloca(3) only warn against using alloca() in function invocations. Declaring
both stack variable and alloca at the same time should be fine: no matter in
which order they happen, i.e. if the pointer variable is above the contents,
or the contents are above the pointer, or even if the pointer is elided by the
compiler, everything should be fine.
../src/core/main.c: In function 'main':
../src/core/main.c:2637:32: error: implicit declaration of function 'cache_efi_options_variable'; did you mean 'systemd_efi_options_variable'? [-Werror=implicit-function-declaration]
(void) cache_efi_options_variable();
^~~~~~~~~~~~~~~~~~~~~~~~~~
systemd_efi_options_variable
Cache it early in startup of the system manager, right after `/run/systemd` is
created, so that further access to it can be done without accessing the EFI
filesystem at all.
In SecureBoot mode this is probably not what you want. As your cmdline
is cryptographically signed like when using Type #2 EFI Unified Kernel
Images (https://systemd.io/BOOT_LOADER_SPECIFICATION/) The user's
intention is then that the cmdline should not be modified. You want to
make sure that the system starts up as exactly specified in the signed
artifact.
This makes the naming more consistent: we now have
bootctl systemd-efi-options,
$SYSTEMD_EFI_OPTIONS
and the SystemdOptions EFI variable.
(SystemdEFIOptions would be redundant, because it is only used in the context
of efivars, and users don't interact with that name directly.)
bootctl is adjusted to use 2sp indentation, similarly to systemctl and other
programs.
Remove the prefix with the old name from 'bootctl systemd-efi-options' output,
since it's redundant and we don't want the old name anyway.
In various circumstances, overriding the kernel commandline can be inconvenient.
People have different bootloaders, and e.g. the grub config can be pretty scary.
grubby helps, but it isn't always available.
This option adds an alternative mechanism that can quite convenient on EFI
systems. cmdline settings have higher priority, because they can be (usually)
changed on the bootloader prompt.
$SYSTEMD_EFI_OPTIONS can be used to override, same as $SYSTEMD_PROC_CMDLINE.
I want to use efivars.[ch] in proc-cmdline.c, but most of the efivars stuff is
not needed in basic/. Move the file from shared/ to basic/, but then move back
most of the higher-level functions to the new shared/efi-loader.c file.
