logname: no login name

[rlesac]

Creating a bug report/issue

• I have searched the existing open and closed issues

Required Information

• DietPi version |
  G_DIETPI_VERSION_CORE=9
  G_DIETPI_VERSION_SUB=2
  G_DIETPI_VERSION_RC=1
  G_GITBRANCH='master'
  G_GITOWNER='MichaIng'

• Distro version |bookworm 1

• Kernel version | Linux DietPi 6.1.21+ #1642 Mon Apr 3 17:19:14 BST 2023 armv6l GNU/Linux

• SBC model | RPi B (armv6l)

• Power supply used | 2A noname

• SD card used | 2gb noname

Additional Information (if applicable)

• Can this issue be replicated on a fresh installation of DietPi?
  Yes
• Bug report ID | echo $G_HW_UUID

Steps to reproduce

1. install dietpi
2. adduser myuser
3. ssh from cygwin or wsl2
4. type logname

Expected behaviour

• logname should return the current username

Actual behaviour

• logname: no login name

Extra details

• I used default settings, except using static IP, and choosing to remove wireless support. I also chose to install vim tiny
• I get the same result with root
• whoami and w work normaly
• tried ssh -T per online suggestions, won't login at all

[Joulinar]

If I'm not mistaken, logname expecting a tty session which ssh normally does not provide.

[rlesac]

I could not install various software I needed to run on the Raspberry pi because of it.
I got a hint that it is SSH related and switched from Dropbear to OpenSSH, and it's now working.

[MichaIng]

logname returns the name of the user logged in based in /var/run/utmp, ignoring sudo/runuser and possible subshells. Dropbear seems to not create that entry, similar to how it does not use all PAM features etc. One can check the w command for registered login sessions.

To be true, I never heard of this command before, but $USER, $LOGNAME variables or whoami command. As you say "various software", which software exactly requires the logname command to be installed?

[rlesac]

logname returns the name of the user logged in based in /var/run/utmp, ignoring sudo/runuser and possible subshells. Dropbear seems to not create that entry, similar to how it does not use all PAM features etc. One can check the w command for registered login sessions.

To be true, I never heard of this command before, but $USER, $LOGNAME variables or whoami command. As you say "various software", which software exactly requires the logname command to be installed?

It's https://github.com/Stefal/rtkbase

[MichaIng]

I see. It uses bash for the installer, and suggests to run it with sudo, so a failsafe replacement (or fallback) for logname would be $SUDO_USER, else $USER variables, which is assured to be set in bash, hence also makes this "empty value" check obsolete.