Bug#1061960: systemd-binfmt.service should get started when something gets added into a previously empty /usr/lib/binfmt.d

[Johannes Schauer Marin Rodrigues]

Package: systemd
Version: 252.19-1~deb12u1
Severity: normal

Hi,

steps to reproduce:

 $ debvm-create
 [...]
 $ debvm-run
 [...]
 root at testvm:~# systemctl status systemd-binfmt.service
 ○ systemd-binfmt.service - Set Up Additional Binary Formats
      Loaded: loaded (/usr/lib/systemd/system/systemd-binfmt.service; static)
      Active: inactive (dead)
   Condition: start condition unmet at Tue 2024-01-30 13:44:24 UTC; 25s ago
              ├─ ConditionDirectoryNotEmpty=|/lib/binfmt.d was not met
              ├─ ConditionDirectoryNotEmpty=|/usr/lib/binfmt.d was not met
              ├─ ConditionDirectoryNotEmpty=|/usr/local/lib/binfmt.d was not met
              ├─ ConditionDirectoryNotEmpty=|/etc/binfmt.d was not met
              └─ ConditionDirectoryNotEmpty=|/run/binfmt.d was not met
 root at testvm:~# apt install qemu-user-static
 [...]
 root at testvm:~# systemctl status systemd-binfmt.service
 ○ systemd-binfmt.service - Set Up Additional Binary Formats
      Loaded: loaded (/usr/lib/systemd/system/systemd-binfmt.service; static)
      Active: inactive (dead)
   Condition: start condition unmet at Tue 2024-01-30 13:44:24 UTC; 2min 47s ago
              ├─ ConditionDirectoryNotEmpty=|/lib/binfmt.d was not met
              ├─ ConditionDirectoryNotEmpty=|/usr/lib/binfmt.d was not met
              ├─ ConditionDirectoryNotEmpty=|/usr/local/lib/binfmt.d was not met
              ├─ ConditionDirectoryNotEmpty=|/etc/binfmt.d was not met
              └─ ConditionDirectoryNotEmpty=|/run/binfmt.d was not met


As a result, just installing a binfmt provider will not immediately enable it.

Starting or restarting makes it work as tested by Jochen Sprickerhof

Maybe the binfmt.d trigger should restart systemd-binfmt.service so that
enabling a new binfmt works without rebooting the machine.

Thanks!

cheers, josch