Re: Questions about XDG_RUNTIME_DIR and server-socket-dir

[Paul Eggert]

Phil Sainty wrote:

> I don't know about XDG_RUNTIME_DIR.  Does that get
> used in ways that rely upon its path never changing?

XDG_RUNTIME_DIR is a per-user-login directory that is like TMPDIR except without 
some of the security problems of TMPDIR (e.g., an attacker can create a symlink 
in TMPDIR to some victim location). That is, XDG_RUNTIME_DIR is accessible only 
to you, whereas TMPDIR traditionally is world-accessible. Also, 
XDG_RUNTIME_DIR's lifetime is intended to be just while the user is logged in. 
For more, please see:

https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html

I don't see the harm in changing it, if each new setting is intended to 
correspond to a different user login. That might be simpler than adding yet 
another environment variable.