RE: [PATCH v7] image-postproc: gate systemd preset-all on masked unit state

["'Prusty, Badrikesh' via isar-users" <isar-users@googlegroups.com>]

Hi,

> I'd propose to revert that "fix" and fix the preset shipped with your distribution accordingly:
>
> e.g.:
> ```
> echo "disable reboot.target" > /usr/lib/systemd/system-preset/00-
> reboot-target-mask.preset
> ```

Thanks for the suggestion!

Unfortunately, shipping a preset file with a "disable" rule won't work
in this case, because populate_systemd_preset applies presets
with:

    systemctl preset-all --preset-mode="enable-only"

This means "disable" rules in preset files are silently ignored.

To make disable rules effective, the --preset-mode flag would need to
be dropped from populate_systemd_preset.


Many thanks,
Badrikesh

-----Original Message-----
From: Heinisch, Alexander (FT RPD CED SES-AT) <alexander.heinisch@siemens.com>
Sent: 01 July 2026 15:12
To: Prusty, Badrikesh (FT FDS CES LX PBU 2) <badrikesh.prusty@siemens.com>; isar-users@googlegroups.com; wzh@ilbers.de
Cc: Kiszka, Jan (FT RPD CED) <jan.kiszka@siemens.com>; Moessbauer, Felix (FT RPD CED OES-DE) <felix.moessbauer@siemens.com>; Çetin, Gökhan (FT D EU TR C&E) <gokhan.cetin@siemens.com>
Subject: Re: [PATCH v7] image-postproc: gate systemd preset-all on masked unit state

Thx for clarifying steps to reproduce.

I followed your steps below with a minor modification to build an existing image (isar-image-base)

```
./kas/kas-container build kas/isar.yaml:kas/machine/x86-
pc.yaml:kas/distro/debian-
bookworm.yaml:kas/package/pkg_hello.yaml:kas/image/isar-image-base.yaml
```

I could reproduce described log output in bookworm.

But, the error message is caused by a conflict you introduced by masking /usr/lib/systemd/system/ctrl-alt-del.target!

ctrl-alt-del.target is a link to reboot.target which is explicitly mentioned enabled in /usr/lib/systemd/system-preset/90-systemd.preset

Therefore, systemd (in bookworm) emits an error.
Later versions of systemd (e.g. the one shipped with trixie) handle that more gracefully [1], as mentioned previously.


TL;DR:

I'd propose to revert that "fix" and fix the preset shipped with your distribution accordingly:

e.g.:
```
echo "disable reboot.target" > /usr/lib/systemd/system-preset/00-
reboot-target-mask.preset
```

BR Alexander


[1]:
https://github.com/systemd/systemd/commit/d41f08bd2ac4cfa58191b64d31ca9e6f3dec7552

On Sat, 2026-06-20 at 04:35 +0000, Prusty, Badrikesh (FT FDS CES LX PBU
2) wrote:
> Hi,
>
> Here are the simple steps to reproduce the issue:
>
> 1. Check out Isar without this patch applied.
>
> 2. Create a recipe to mask a unit. Here I am using `ctrl-alt-
> del.target` ```
> > cat meta-isar/recipes-example/no-ctrl-alt-del/no-ctrl-alt-del.bb
> inherit dpkg-raw
>
> SRC_URI = "file://postinst"
>
> > cat meta-isar/recipes-example/no-ctrl-alt-del/files/postinst
> #!/bin/sh
>
> systemctl mask ctrl-alt-del.target
> ```
>
> 3. Install it to the rootfs:
> ```
> > git diff
> diff --git a/kas/package/pkg_hello.yaml b/kas/package/pkg_hello.yaml
> index ea2bce8e..382acd29 100644
> --- a/kas/package/pkg_hello.yaml
> +++ b/kas/package/pkg_hello.yaml
> @@ -6,4 +6,4 @@ header:
>
>  local_conf_header:
>    package-hello: |
> -    IMAGE_INSTALL:append = " hello"
> +    IMAGE_INSTALL:append = " hello no-ctrl-alt-del"
> ```
>
> 4. Trigger a build with distro set to debian-bookworm:
> ```
> > ./kas/kas-container build kas/isar.yaml:kas/machine/x86-
> > pc.yaml:kas/distro/debian-bookworm.yaml:kas/package/pkg_hello.yaml
> ```
>
> Error log:
> ```
> > DEBUG: Executing shell function
> > image_postprocess_populate_systemd_preset
> > Failed to preset unit, unit /etc/systemd/system/systemd-
> > firstboot.service is masked.
> > Failed to preset unit, unit /etc/systemd/system/ctrl-alt-del.target
> > is masked.
> > Failed to preset unit, unit /lib/systemd/system/x11-common.service
> > is masked.
> > Failed to preset unit, unit /lib/systemd/system/rc.service is
> > masked.
> > Failed to preset unit, unit /lib/systemd/system/cryptdisks.service
> > is masked.
> > Failed to preset unit, unit /lib/systemd/system/cryptdisks-
> > early.service is masked.
> > Failed to preset unit, unit /lib/systemd/system/rcS.service is
> > masked.
> > Failed to preset unit, unit /lib/systemd/system/hwclock.service is
> > masked.
> > Unit /etc/systemd/system/systemd-firstboot.service is masked,
> > ignoring.
> > Unit /etc/systemd/system/ctrl-alt-del.target is masked, ignoring.
> > Created symlink /etc/systemd/system/multi-user.target.wants/remote-
> > cryptsetup.target → /lib/systemd/system/remote-cryptsetup.target.
> > Created symlink /etc/systemd/system/sysinit.target.wants/systemd-
> > sysext.service → /lib/systemd/system/systemd-sysext.service.
> > Unit /lib/systemd/system/x11-common.service is masked, ignoring.
> > Unit /lib/systemd/system/rc.service is masked, ignoring.
> > Failed to preset unit, file "/etc/systemd/system/ctrl-alt-
> > del.target" already exists and is a symlink to "/dev/null".
> ```
>
> Many thanks,
> Badrikesh
>
> -----Original Message-----
> From: Heinisch, Alexander (FT RPD CED SES-AT)
> <alexander.heinisch@siemens.com>
> Sent: 20 June 2026 02:07
> To: Prusty, Badrikesh (FT FDS CES LX PBU 2)
> <badrikesh.prusty@siemens.com>; isar-users@googlegroups.com;
> wzh@ilbers.de
> Cc: Kiszka, Jan (FT RPD CED) <jan.kiszka@siemens.com>; Moessbauer,
> Felix (FT RPD CED OES-DE) <felix.moessbauer@siemens.com>; Çetin,
> Gökhan (FT D EU TR C&E) <gokhan.cetin@siemens.com>
> Subject: Re: [PATCH v7] image-postproc: gate systemd preset-all on
> masked unit state
>
> On Mon, 2026-06-15 at 11:02 +0200, Zhihang Wei wrote:
> > Applied to next, thanks.
> >
> > Zhihang
> >
> > On 4/29/26 15:02, 'Badrikesh Prusty' via isar-users wrote:
> > > Skip systemd preset-all during image postprocessing if masked unit
> > > files are detected, to avoid non-fatal failures when presetting
> > > units that are already masked.
> > >
> > > Move execution fully inside a single chroot invocation for
> > > consistency and reduced overhead.
> > >
> > > Fixes: 72b88a12 ("classes/image-postproc: Enable systemd units
> > > based on systemd presets")
> Sorry for the (too)late reply.
>
> Can you elaborate what this fix is about?
>
> At least on my systems (and according to documentation) preset-all --
> preset-mode="enable-only" handles masked services gracefully.
>
> The command emits:
> "Unit [redacted].service is masked, ignoring." correctly.
> but exits with exit code 0.
>
> Further, the previous behavior is exactly what systemd does on first
> boot anyways.
>
> BR Alexander
>
> > >
> > > Signed-off-by: Badrikesh Prusty <badrikesh.prusty@siemens.com>
> > > ---
> > >   meta/classes-recipe/rootfs.bbclass | 13 +++++++------
> > >   1 file changed, 7 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/meta/classes-recipe/rootfs.bbclass b/meta/classes-
> > > recipe/rootfs.bbclass index 8b502a50..d250690f 100644
> > > --- a/meta/classes-recipe/rootfs.bbclass
> > > +++ b/meta/classes-recipe/rootfs.bbclass
> > > @@ -569,13 +569,14 @@ EOSUDO
> > >
> > >   ROOTFS_POSTPROCESS_COMMAND +=
> > > "${@bb.utils.contains('ROOTFS_FEATURES', 'populate-systemd-
> > > preset', 'image_postprocess_populate_systemd_preset', '', d)}"
> > >   image_postprocess_populate_systemd_preset() {
> > > -    SYSTEMD_INSTALLED=$(sudo chroot '${ROOTFSDIR}' dpkg-query \
> > > -        --showformat='${db:Status-Status}' \
> > > -        --show systemd || echo "" )
> > > +    sudo chroot "${ROOTFSDIR}" /bin/sh <<'EOSH'
> > > +        SYSTEMD_INSTALLED=$(dpkg-query --
> > > showformat='${db:Status-
> > > Status}' --show systemd 2>/dev/null)
> > >
> > > -    if (test "$SYSTEMD_INSTALLED" = "installed"); then
> > > -        sudo chroot '${ROOTFSDIR}' systemctl preset-all --
> > > preset-
> > > mode="enable-only"
> > > -    fi
> > > +        if [ "${SYSTEMD_INSTALLED}" = "installed" ]; then
> > > +            systemctl list-unit-files --state=masked --no-legend
> > > |
> > > grep -q '^' \
> > > +                || systemctl preset-all --preset-mode="enable-
> > > only"
> > > +        fi
> > > +EOSH
> > >   }
> > >
> > >   do_rootfs_postprocess[vardeps] = "${ROOTFS_POSTPROCESS_COMMAND}"
> > > --
> > > 2.47.3
> > >
>
> --
> Alexander Heinisch
> Siemens AG
> http://www.siemens.com/

--
Alexander Heinisch
Siemens AG
http://www.siemens.com/

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