Systemd-259.1

Configuring Systemd

The /etc/pam.d/system-session file needs to be modified and a new file needs to be created in order for systemd-logind to work correctly. Run the following commands as the root user:

grep 'pam_systemd' /etc/pam.d/system-session ||
cat >> /etc/pam.d/system-session << "EOF"
# Begin Systemd addition

session  required    pam_loginuid.so
session  optional    pam_systemd.so

# End Systemd addition
EOF

cat > /etc/pam.d/systemd-user << "EOF"
# Begin /etc/pam.d/systemd-user

account  required    pam_access.so
account  include     system-account

session  required    pam_env.so
session  required    pam_limits.so
session  required    pam_loginuid.so
session  optional    pam_keyinit.so force revoke
session  optional    pam_systemd.so

auth     required    pam_deny.so
password required    pam_deny.so

# End /etc/pam.d/systemd-user
EOF

As the root user, replace the running systemd manager (the init process) with the systemd executable newly built and installed:

systemctl daemon-reexec

A desktop environment often runs as a group of user services. These services are spawned by the per-user instance, instead of the login shell. To ensure those services get the environment variables set from /etc/profile.d, as the root user, install an environment generator to dump all the relevant exported environment variables into the per-user instance when the instance starts to run:

install -vDm755 /dev/stdin /etc/systemd/user-environment-generators/50-profile.sh << "EOF"
#!/usr/bin/env -S -i /usr/bin/bash
# SPDX-License-Identifier: MIT

. /etc/profile

# Systemd should have already set a better value for them.
unset XDG_RUNTIME_DIR
for i in $(locale); do
  unset ${i%=*}
done

# Some shell magic that we don't want to expose.
unset SHLVL

# Systemd does not want to pass functions to the environment
for i in $(declare -pF | awk '{print $3}'); do
  unset -f $i
done

python3 << _EOF
import os
for var in os.environ:
  # Simply unsetting them in shell does not work.
  if var in ['LC_CTYPE', '_']:
    continue

  print(var + '=' + os.environ[var])
_EOF
EOF

Read systemd.environment-generator(7) for details about the environment generators.

systemctl --user unset-environment \
  $(/etc/systemd/user-environment-generators/50-profile.sh | sed 's/=.*//')
systemctl --user daemon-reload