cross-posted from: https://reddthat.com/post/21668140

I have a VPN daemon that needs to run before the client will work. Normally, this would have been set up automatically by its install script, but the system is immutable.

I’ve created the systemd service via sysyemctl edit --force --full daemon.service with the following parameters:

[Unit] 
Description=Blah
After=network-online.target

[Service]
User=root
Group=root
ExecStart=/usr/bin/env /path/to/daemon

[Install]
WantedBy=multi-user.target

I’ve verified that the daemon is actually executable, and it runs fine when I manually call it via sudo daemon. When I try to run it with sudo systemctl enable --now daemon.service, it exits with error code 126.

What am I missing?

Edit: Typo, and added the relevant user and group to the Service section. Still throwing a 126.

Solution: the system wanted /usr/bin/env in ExecStart to launch the binary. The .service file above has been edited to show the working solution.

  • RustmilianEnglish
    4•5 months ago

    On that, make sure it’s in the root systemd path. Something like /etc/systemd/system/blah.service, placing it in the user systemd service path (~/.config/systemd/user/) will cause permission errors as it’ll try accessing the root user from the current user.

    • @[email protected]OPEnglish
      2•5 months ago

      Thanks, I verified that it’s in the correct place. Still throwing a 126 (see the modifications in the edit).

      • RustmilianEnglish
        1•5 months ago

        What’s the specific VPN service? I’ll check their docs.

          • RustmilianEnglish
            1•5 months ago

            I assume so, but just to be sure, have you run sudo systemctl enable blah.service then reboot? It’ll symbolic link to the systemd auto start service and run it at boot.
            Also, make sure everything is marked as executable; especially whatever you have “/path/to/daemon” set as. sudo chmod +x /path/to/daemon
            Restart the service or reboot then :
            sudo systemctl status blah.service

            • @[email protected]OPEnglish
              2•5 months ago

              Yep, more specifically I tried sudo systemctl enable --now daemon.service. Gives the same error, and maybe that’s because it’s some kind of binary.

              sudo /bin/bash /path/to/daemon throws the same error, but sudo /path/to/daemon does not. However, if I drop , /bin/bash from the service file, it throws a 203 error instead.

              • RustmilianEnglish
                3•5 months ago

                Is the daemon a binary? If so drop the bash part and try sudo chmod 755 /path/to/daemon.

                • @[email protected]OPEnglish
                  3•5 months ago

                  Tried that, back to 203/Exec error. It’s like ExecStart wants me to specify a program to launch it, and bash clearly isn’t it.

                  • RustmilianEnglish
                    3•5 months ago

                    Try ExecStart=/usr/bin/env /path/to/daemon
                    Also what’s the output of ldd /path/to/daemon & sudo systemd-run /path/to/daemon ? Maybe check systemctl show-environment. Maybe try adding Type=simple , this tells systemd that the service will fork.

                    If that fails, we could try ExecStart=/usr/bin/strace -f -o /tmp/daemon_strace.log /path/to/daemon for stactrace & ExecStart=/bin/sh -c '/path/to/daemon > /tmp/daemon.log 2>&1' to log the daemon.