codesigning, the macports user (and other users added by MacPorts) and diskspace (IconServicesAgent) [was Re: lldb ...]

[René J.V. Bertin]

On Sunday September 18 2016 19:23:01 Jeremy Huddleston Sequoia wrote:

>>> Yes, of course it's possible.  Don't.  There's nothing special about the UID in this case that has anything to do with what you're seeing.
>> 
>> So what does make the difference?
>
>What is "the difference" that you want?  All users have a user session, and if logged in to the gui, they also have an aqua (gui) session.  All users.

As I said, there's an order of magnitude difference in the size of the icon cache for users like root, and that of users like macports or ldap.

The icon cache sits in the user's $TMPDIR, and AFAIK that directory is emptied at boot. My machine has been up for 35 days, and in that time I certainly didn't log any of the "incriminated" users into an aqua session. I did things as the macports user that could explain why an IconServiceAgent was started for it, but that's it. FWIW, I removed the entries for a few other users before reporting here, including avahi - those haven't come back yet.

A difference I could think of is a setting that tells the system not to let a particular user log in to a gui session. Which is why I thought of a UID<500; those at least don't show up in the login manager. But maybe they can still be logged in if the login manager is in traditional text (= no icon) mode?

>> Possibly a tool, but what could have that effect? AFAIK the icon cache is chiefly used by the Finder, so anything that leverages the Finder might cause an icon cache to be populated.
>
>It's marked as RunAtLoad on my system (Sierra).  That would explain why it's running, even if nothing needs it...

But RunAtLoad for whom, and when? Boot time? Or login, and if so, what kind of login? How many copies do you have running now?

What surprises me is that every user would have to need a personal icon cache for every icon in the system. I know user A could have an app installed with a doc type having a particular icon that no other user on the system is likely to encounter, but would it hurt if they did get to see the icon if they stumbled across such a document? IOW, would it be bad if all file-to-icon associations were cached in a central location, 1 copy for everyone?
Not only does that cache get big, it also consists of plenty of small files, which makes its actual footprint on disk even larger (due to blocksize; I think that hasn't changed with SSDs?).

R.