Fix static IP not set if IP is already present in any way inside dhcpcd.conf

[StephanPillhofer]

Signed-off-by: Stephan Pillhofer 43667664+StephanPillhofer@users.noreply.github.com

• What does this PR aim to accomplish?:

This PR solves a bug which prevents the dhcpcd.conf file from being changed when the user wants to assign a static IP address to the RaspberryPi. The bug occurs because the target static IP address may already be present in any form in the (default) dhcpcd.conf file. (e.g. the IP address may be mentioned in another setting than "static ip_address" or it may be present in a commented example setting)

• How does this PR accomplish the above?:

The bug is resolved by utilizing a regular expression for matching a valid non-commented static IP addess entry (e.g. static ip_address=192.168.10.2/24)

• What documentation changes (if any) are needed to support this PR?:

none

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[StephanPillhofer]

A certificate error (cert expired) causes a centos_9 test to fail. Addidtionally the mirror links return a 404. Shouldn't be related to the PR.

E           [mirror] dbus-libs-1.12.20-6.el9.x86_64.rpm: curl error (60): ssl peer certificate or ssh remote key was not ok for https://mirror.grid.uchicago.edu/pub/linux/centos-stream/9-stream/baseos/x86_64/os/packages/dbus-libs-1.12.20-6.el9.x86_64.rpm [ssl certificate problem: certificate has expired]
E         ?                                                   +++++
E           [mirror] dnf-plugins-core-4.1.0-3.el9.noarch.rpm: curl error (60): ssl peer certificate or ssh remote key was not ok for https://mirror.grid.uchicago.edu/pub/linux/centos-stream/9-stream/baseos/x86_64/os/packages/dnf-plugins-core-4.1.0-3.el9.noarch.rpm [ssl certificate problem: certificate has expired]
E           [mirror] python3-dateutil-2.8.1-6.el9.noarch.rpm: curl error (60): ssl peer certificate or ssh remote key was not ok for https://mirror.grid.uchicago.edu/pub/linux/centos-stream/9-stream/baseos/x86_64/os/packages/python3-dateutil-2.8.1-6.el9.noarch.rpm [ssl certificate problem: certificate has expired]

[yubiuser]

With the anchors, the -x option should not be necessary anymore.
__

The current code with the ending anchor will fail with something like this

static ip_address = 192.168.0.5 #comment

I think the trailing anchor should be removed.

[StephanPillhofer]

You are right, didn't think about the possibility of adding a comment at the end. Also the -x can be removed. Should I create a new PR to fix it?

New Regex will be: regex="^[ \t]*static ip_address[ \t]*=[ \t]*${IPV4_ADDRESS}" (tested)

[yubiuser]

I also tested with different regex/grep combinations and came to the same conclusion. Please open a new PR if you want :)

[dschaper]

Is an inline trailing comment a valid configuration?

[yubiuser]

The manual says

Comments may be placed anywhere within the file (except within quotes). Comments begin with the # character and end at the end of the line.

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Ok, this was for dhcpd.conf. Sorry.

[dschaper]

Can you link to that please?

The only thing I have found is

The first word on the line is the option and the rest of the line is the value. Leading and trailing whitespace for the option and value are trimmed. You can escape characters in the value using the \ character. Comments can be prefixed with the # character. String values should be quoted with the " character.

From https://manpages.debian.org/testing/dhcpcd5/dhcpcd.conf.5.en.html

[StephanPillhofer]

So in the worst case the comment may be part of the "value" part which would not be good.

[yubiuser]

The relevant code section should be

https://github.com/NetworkConfiguration/dhcpcd/blob/6a9994bbf00712ace77a835cb7e45558383be673/src/common.c#L181-L195

[StephanPillhofer]

Apparently it seems to be valid:

noipv6rs                 # disable routing solicitation
denyinterfaces eth2      # Don't touch eth2 at all
interface eth0
  ipv6rs                 # enable routing solicitation for eth0
  ia_na 1                # request an IPv6 address
  ia_pd 2 eth1/0         # request a PD and assign it to eth1
  ia_pd 3 eth2/1 eth3/2  # req a PD and assign it to eth2 and eth3

From: https://www.daemon-systems.org/man/dhcpcd.conf.5.html (scroll a bit down)

[StephanPillhofer]

The relevant code section should be

https://github.com/NetworkConfiguration/dhcpcd/blob/6a9994bbf00712ace77a835cb7e45558383be673/src/common.c#L181-L195

My c is not the best but I would also see the code as an indication that it is valid to do inline comments.

[dschaper]

Yeah, the c code that Yubi linked to does truncate the lines at the first #, so trailing line comments are perfectly valid.

[dschaper]

My c is not great either but my Stack Overflow is Ninja level.

[StephanPillhofer]

New PR created: #4998