HOME doesn't get set properly

[klaemo]

Hey,
it seems like HOME doesn't get set properly. See the following example (I tried it in a debian/wheezy docker container)

useradd -d /var/lib/couchdb couchdb

the user is set up correctly it seems:

$ su couchdb -c env
[...]
USER=couchdb
HOME=/var/lib/couchdb
[...]

but gosu doesn't set HOME correctly

$ gosu couchdb env
[...]
USER=couchdb
HOME=/root
[...]

Am I missing something?

Thanks!

[pwaller]

The current behaviour looks like it will set HOME only if it is set to a (non-empty-string) value before hand:

    // if we didn't get HOME already, set it based on the user's HOME
    if envHome := os.Getenv("HOME"); envHome == "" {
        if err := os.Setenv("HOME", execUser.Home); err != nil {
            return fmt.Errorf("set HOME %s", err)
        }
    }

[tianon]

Indeed, this is essentially working as designed. I'm open to the idea of having a way to explicitly say "I want HOME to be set for sure", but I don't see how gosu --some-flag ... is really any better than just HOME= gosu ..., right?

This comes from Docker's own code where if someone sets ENV HOME ... in their Dockerfile, we don't want to overwrite it, but if they don't, we want to set it based on the user. It could be argued that the use-case for gosu means we ought to set it regardless. I'm always open for more discussion! 👍

[klaemo]

I see your point. I guess I was expecting gosu to work similarly to su or sudo in that regard. Maybe just adding a note in the Readme about this would help clarify the situation for future users.

I'm still not quite sure what the best way forward is though.

if someone sets ENV HOME ... in their Dockerfile, we don't want to overwrite it, but if they don't, we want to set it based on the user.

Hm, but it doesn't set it based on the user though, does it? That's why my above example shows HOME=/root. Perhaps it is more intuitive to just switch to the user's HOME by default and add a flag like --home to be able to overwrite it.

I don't know...it just took me a while to figure out to use HOME=/foo gosu... because I thought my user and everything were setup properly.

[tehbilly]

Unless I'm mistaken, the current behavior is the same as sudo's behavior, correct? You're not creating a session as the user you're invoking a command as, I wouldn't expect their profile information to be present in the environment. I think making a change like this would be more harmful than helpful, especially since you can invoke the command like HOME=/home/joe gosu ... if you need different behavior in an edge case.

[vmaatta]

Unless I'm mistaken, the current behavior is the same as sudo's behavior, correct?

FWIW, wrong, at least in debian.

$ sudo -u www-data env
…
USER=www-data
USERNAME=www-data
MAIL=/var/mail/www-data
HOME=/var/www
…

There are some differences in the ENV set by su -c and sudo but they both do set HOME.

if you need different behavior in an edge case

I.e. expecting HOME can't very well be said to be an edge case when both su -c and sudo do set it.

[tianon]

Ok, I'm convinced. Will be making a fix for this shortly and cutting a new release.

[klaemo]

Thanks, tianon!