Parts that affect me look good

@jrtc27 @imp Thanks again for your timely feedback, much appreciated.

In D43350#988235, @imp wrote:

This seems like a reasonable first step to getting accomplishing this.
Though the code repetition and general concept suggest that maybe this design point might be best revisited int the future.

@jrtc27 @imp Any additional remarks? Once landed (and if time permits) I thought about improving bsdinstall's use of quoting in a separate review.

Minor style fix

Only delete setup script (as preamble will always be overwritten)

@jrtc27 Retested bsdinstall jail after the change. Note that I didn't bother to quote TMPDIR, as it would've been odd in that codebase (compare use of other paths in bsdinstall, e.g., BSDINSTALL_CHROOT). Fixing these things should be done when refactoring/in a separate effort.

Incorporate feedback given in review

In D43350#988058, @jrtc27 wrote:

Tested locally using SCRIPT=myinstallscript bsdinstall jail.

Also fix for jail command

@kp thanks for the review

@kp here you go (lint error seems to be a false positive)

post merge clesanup

Add unit test

I haven't tested the changes myself, but this looks sound to me.

@markj @jrm I just committed be146a923dbda66f50c6b04b406da790837f6287 (cgit link) which addresses the issue in a more generic fashion (since we had these kinds of errors pop up over and over again). Even though I tested this locally and it seems to work as expected, it would be great if you could verify this at your end as well.

@markj Thanks, I'll look into it