Ensure character encoding can be detected by tlog on Fedora and RHEL

[spbnick]

At the moment, at least on Fedora, when logging in via login on console or with su, tlog is supplied with ASCII as the character encoding to use and aborts (because it only supports UTF-8). At the same time ASCII is not the actual character encoding to use, and the configured encoding is in fact UTF-8. This is due to Fedora (at least) setting it in /etc/locale.conf, to be sourced by shells when they read startup files.

This ad-hoc solution is leaving other programs, which are not prepared to interpret shell language (or even just the limited language of /etc/locale.conf) in the cold. Instead something like the Debian approach should be used. Debian sets locale using pam_env, which works for any program.

Find a way to read Fedora (and RHEL) locale settings in tlog, and/or change the way the distributions do it.

[spbnick]

See also Scribery/tlog#78.

[spbnick]

A (rather burdensome) workaround can be for user to set up pam_env themselves.

[spbnick]

The pam_env workaround can be putting this into /etc/pam.d/system-auth:

session     required      pam_env.so readenv=1 envfile=/etc/locale.conf

Putting it before this line seems to work:

session     required      pam_limits.so

[spbnick]

I started a discussion of locale environment setup in Fedora on devel@lists.fedoraproject.org:
https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/37B7RLKU5JYKUK46ANTUADNRGELW6U7O/

[spbnick]

There was no response to the message on Fedora devel maillist.

[spbnick]

Getting in touch with PAM maintainers next.

[spbnick]

Tomas Mraz, the PAM and authconfig maintainer in Fedora seems to be fine with the PAM-based fix as long as the format of /etc/locale.conf is within what pam_env.so expects. I raised systemd-devel to check, and run the whole idea past them.

[spbnick]

Another approach could be letting the systemd and login pass the locale environment variables read and set by systemd-logind.

First these lines need to be removed from the /lib/systemd/system/getty@.service file:

# Unset locale for the console getty since the console has problems
# displaying some internationalized messages.
Environment=LANG= LANGUAGE= LC_CTYPE= LC_NUMERIC= LC_TIME= LC_COLLATE= LC_MONETARY= LC_MESSAGES= LC_PAPER= LC_NAME= LC_ADDRESS= LC_TELEPHONE= LC_MEASUREMENT= LC_IDENTIFICATION=

And the following line in the same file:

ExecStart=-/sbin/agetty --noclear %I $TERM

needs to be changed to this:

ExecStart=-/sbin/agetty -o "-p -- \u" --noclear %I $TERM

[spbnick]

A fix for the above was submitted to systemd: systemd/systemd#6023

[spbnick]

Discussion with systemd upstream is still ongoing, but we have the fallback path of the PAM configuration.