Environment variables in /etc/issue do not get evaluated correctly

[fstraetz]

Describe the bug
In case one uses tuigreet with the /etc/issue file, tuigreet will not evaluate the contents of the file in the correct way (anymore?). To be more specific, environment variables like PRETTY_NAME (as defined in /etc/os-release) used in /etc/issue are not resolved at all.

To Reproduce
Steps to reproduce the behavior:

1. Modify /etc/issue in a way that it contains an environment variable, e. g., \S{PRETTY_NAME} \r (\l).
2. Restart the system or otherwise bring up tuigreet with the reloaded changes.
3. tuigreet should now show the {PRETTY_NAME} as-is, i. e., unresolved.

Expected behavior
The expectation would be that tuigreet tries to resolve all environment variables found in the /etc/issue file.

System information:

• Distribution: Manjaro Linux (stable, updated 2024-11-30)
• greetd version: 0.10.3-1
• tuigreet version: 0.9.1-1
• Installation method (from source, package, binary, etc.): package (from distribution)
• tuigreet command line: tuigreet --user-menu --user-menu-min-uid 1000 --remember --remember-session --time --issue --asterisks

Additional context
In all honesty, I am not sure whether this ever worked or whether the /etc/issue file got changed by some distribution update to contain the environment variable. But there were some recent relevant commits / changes to the /etc/issue handling, so I could imagine that something regarding the environment variable handling got changed. In case this actually never worked, it might be a nice addition.

Debug log
The recommended command outputs GREETD_SOCK must be defined and exits, no matter whether run as user or as root.

[BluishHumility]

I noticed this as well. Last month Arch Linux changed /etc/issue in this commit: https://gitlab.archlinux.org/archlinux/packaging/packages/filesystem/-/commit/2b36e79ea95db61144f54d187f32e949edbd28a6

Before this change, "Arch Linux" appears normally above the login prompt when using the -i flag, along with the kernel version and the TTY in use:

After the file was changed to a variable, "Linux{PRETTY_NAME}" is printed instead.

[harogaston]

Same issue here

[dvzrv]

Hi! I merged the relevant changes for Arch Linux.

The relevant documentation for this (agetty) can be found here: https://man.archlinux.org/man/agetty.8#ISSUE_FILES

I guess on the one hand one wants a os-release parser and a parser for the custom "environment variable" format in /etc/issue so that this can be displayed properly.

[harogaston]

Hi! I merged the relevant changes for Arch Linux.

The relevant documentation for this (agetty) can be found here: https://man.archlinux.org/man/agetty.8#ISSUE_FILES

I guess on the one hand one wants a os-release parser and a parser for the custom "environment variable" format in /etc/issue so that this can be displayed properly.

Hi @dvzrv , sorry, what did you merge? and where exactly?

[dvzrv]

sorry, what did you merge? and where exactly?

see #169 (comment)

I noticed this as well. Last month Arch Linux changed /etc/issue in this commit: https://gitlab.archlinux.org/archlinux/packaging/packages/filesystem/-/commit/2b36e79ea95db61144f54d187f32e949edbd28a6