On Tue, 4 Jan 2022 at 14:40, David <bouncingc...@gmail.com> wrote: > There are a couple of unexpected aspects to script #2, which I will > explain ... > > a) Script sequencing > > or "Why has he put it under /usr ?" > > All the PREREQ= and prereqs stuff is a mechanism to control the > sequencing of scripts in each subdirectory under > '*/initramfs-toos/scripts/'. > > How to use that mechanism will depend on how the other scripts present > are already using it. Above I left it unused because I had to use a > different approach, so PREREQ was irrelevant and I never assigned it > any values. This seems common in other scripts too, when order does > not matter. > > For my situation it was essential to ensure that Step #2 ran before > the interactive cryptsetup password prompt script in the initrd. > > So I had to take note of where that occurs in the whole sequence of > different subdirectories, and ensure that my script ran before. > > And a complicating factor is that 'man initramfs-tools' says: > > Please notice that PREREQ is only honored inside a single directory. > So first the scripts in /usr/share/initramfs-tools are ordered > according to their PREREQ values and executed. Then all scripts in > /etc/initramfs-tools are ordered according to their PREREQ values and > executed. This mean that currently there is no possibility to have a > local script (/etc/initramfs-tools) get executed before one from the > package (/usr/share/initramfs-tools). > > Note the last sentence. Even though I suspect it ambiguously > overstates the problem, that explains why my script *must* be placed > in '/usr/..../local-top' subdirectory and not under /etc as would be > more desirable. I could not see any way to have it under /etc and > be sure that it would run early enough. I tried that, and it worked.
Realised that I forgot to articulate something important in that explanation ... The other "boot script" /usr/share/initramfs-tools/scripts/local-top/cryptroot is what provides the interactive cryptsetup password prompt. And it contains prereqs() logic to ensure that it runs *last* of all scripts in that '/usr/.../local-top' directory. That is why my my_kdbrate script: - must be in that directory /usr...local-top, so it runs before; - cannot be placed under /etc, which would run after; - does not need to specify any PREREQ, already managed.
