PXE Boot - errors in dhclient-script: busybox chmod: unrecognized option --reference

[James Verbunk]

When booting 22.04.1 using ISO pulled vmlinuz/initrd/squashfs there are some errors in /sbin/dhclient-script. IDs redacted.

Internet Systems Consortium DHCP Client 4.4.1
Copyright 2004-2018 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eno1/f0:92:~:~:~:~
Sending on LPF/eno1/f0:92:~:~:~:~
Sending on Socket/fallback
DHCPDISCOVER on eno1 to 255.255.255.255 port 67 interval 3 (xid=0xa9d4e16d)
DHCPOFFER of 10.0.~.~ from 10.0.~.1
DHCPREQUEST for 10.0.~.~ on eno1 to 255.255.255.255 port 67 (xid=0x6de1d4a9)
DHCPACK of 10.0.~.~ from 10.0.~.1 (xid=0xa9d4e16d)
/sbin/dhclient-script: line 99: chown: not found
chmod: unrecognized option '--reference=/etc/resolv.conf'
BusyBox v1.30.1 (Ubuntu 1:1.30.1-7ubuntu3) multi-call binary.

Usage: chmod [-R] MODE[,MODE]... FILE...

Each MODE is one or more of the letters ugoa, one of the
symbols +-= and one or more of the letters rwxst

 -R Recurse
bound to 10.0.~.~ -- renewal in 2963 seconds.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1990618

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[James Verbunk (verbunk)]

I can not boot into the full environment to collect logs.

[Benjamin Drung (bdrung)]

You found an incompatibility of /sbin/dhclient-script with busybox. Relevant code snippet:

```
        if [ -f $resolv_conf ]; then
            chown --reference=$resolv_conf $new_resolv_conf
            chmod --reference=$resolv_conf $new_resolv_conf
        fi
```

The chown command from busybox does not have a --reference parameter.

Simplified test case:

```
touch resolve.conf
busybox chown --reference=/etc/resolv.conf resolve.conf
```

This also fails for Ubuntu 23.10 (mantic).

Can you document the steps to reproduce it? The amd-net autopkgtest test cases for initramfs-tools do not trigger the bug (probably because they to not trigger the if-condition).