Date: Thu, 11 May 2023 10:32:20 -0700 (PDT) From: "Rodney W. Grimes" <freebsd@gndrsh.dnsmgr.net> To: Mike Karels <mike@karels.net> Cc: rgrimes@freebsd.org, src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 36db6b04962a - main - hier(7): document /home/ and /usr/home/ Message-ID: <202305111732.34BHWKdw059416@gndrsh.dnsmgr.net> In-Reply-To: <20A9CE7A-0859-4581-8445-60456B1A497B@karels.net>
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> On 11 May 2023, at 9:58, Rodney W. Grimes wrote: > > >> On Wed, 10 May 2023 16:48:12 -0500 > >> Mike Karels <mike@karels.net> wrote: > >> > >>> On 10 May 2023, at 10:13, Cy Schubert wrote: > >>> > >>>> In message <ba22a75d-06c0-371e-603e-7ded9d1dca97@freebsd.org>, Mitchell > >>>> Horne w > >>>> rites: > >>>>> On 5/10/23 11:19, Rodney W. Grimes wrote: > >>>>>>> The branch main has been updated by mhorne: > >>>>>>> > >>>>>>> URL: https://cgit.FreeBSD.org/src/commit/?id=36db6b04962a01ff7b21592def02d > >>>>> 4c570dac939 > >>>>>>> > >>>>>>> commit 36db6b04962a01ff7b21592def02d4c570dac939 > >>>>>>> Author: Mitchell Horne <mhorne@FreeBSD.org> > >>>>>>> AuthorDate: 2023-05-10 12:53:56 +0000 > >>>>>>> Commit: Mitchell Horne <mhorne@FreeBSD.org> > >>>>>>> CommitDate: 2023-05-10 13:25:17 +0000 > >>>>>>> > >>>>>>> hier(7): document /home/ and /usr/home/ > >>>>>>> > >>>>>>> Reviewed by: imp > >>>>>>> MFC after: 1 week > >>>>>>> Sponsored by: The FreeBSD Foundation > >>>>>>> Differential Revision: https://reviews.freebsd.org/D40002 > >>>>>>> --- > >>>>>>> share/man/man7/hier.7 | 10 ++++++++++ > >>>>>>> 1 file changed, 10 insertions(+) > >>>>>>> > >>>>>>> diff --git a/share/man/man7/hier.7 b/share/man/man7/hier.7 > >>>>>>> index ff11289436a1..b6759dd6e65b 100644 > >>>>>>> --- a/share/man/man7/hier.7 > >>>>>>> +++ b/share/man/man7/hier.7 > >>>>>>> @@ -90,6 +90,10 @@ file descriptor files; > >>>>>>> see > >>>>>>> .Xr \&fd 4 > >>>>>>> .El > >>>>>>> +.It Pa /home/ > >>>>>>> +user HOME directories. > >>>>>>> +This is a symlink to > >>>>>>> +.Pa /usr/home/ > >>>>>> > >>>>>> /usr is "contains the majority of user utilities and applications" > >>>>>> it should not contain home directories. > >>>>>>> I do not know when this move to usr came about it was traditionally > >>>>> /home. > >>>>>> I do not know why /usr/home even exists, it is not needed by > >>>>>> anything I am aware of. If we have a compatible link it > >>>>>> should be, usr/home -> ../home and /home should be the > >>>>>> directory. > >>>>>> > >>>>> > >>>>> I agree that /usr/home is strange, and is unique (?) to FreeBSD. > >>>>> > >>>>> The oldest commit in the output of `git log --grep '/usr/home'` is: > >>>>> > >>>>> commit f2400d465896a8e4f6fdc57eba840cf49b25bbbd > >>>>> Author: David Nugent <davidn@FreeBSD.org> > >>>>> Date: Fri Jan 3 04:42:18 1997 +0000 > >>>>> > >>>>> Implemented /home -> /usr/home symlink kludge. > >>>>> If home basedir would be created in the root partition, create > >>>>> it under /usr instead, and symlink /basedir -> /usr/basedir. > >>>>> > >>>>> Notes: > >>>>> svn path=/head/; revision=21242 > >>>>> > >>>>> > >>>>> So it has been this way for 26 years at least. I do not know what to say > >>>>> about whether /usr "should" contain it, but it does. > >>>> > >>>> Usually history matters. I can understand not changing it. On the flip > >>>> side, I cut my UNIX teeth on SunOS 4 and Solaris where /home was /home -- > >>>> albeit automounted from /export/home on localhost or some NFS server. In > >>>> the Red Hat land at $JOB, /home is its own partition (actually an LVM > >>>> volume). In both cases /home is not in /usr because end-users can fill > >>>> /usr. This can be problematic operationally because it's yet another > >>>> headache to deal with should someone fill the filesystem. Filling /usr is > >>>> more serious than filling /home. > >>>> > >>>> As a point of interest, when I installed my first FreeBSD many moons ago I > >>>> used the Solaris standard of /export/home, using amd (now automount) to > >>>> serve my /home. I'm not advocating we do this, it's overkill, but /home > >>>> should not live in /usr. It's a potential headache for any sysadmin. > >>>> > >>>> With ZFS the solution is easy. With UFS based systems there are a lot of > >>>> other factors that go into how we install the "default" from the get-go. > >>> > > > > First off, thank you Mike for looking at this closer. Add me to any reviews > > you might creat. > > > >>> The situation is a fair mess. It took me a little while to figure out that > >>> the kludge referenced above is in the pw(8) command, which is used as the > >>> backend to adduser(8). Neither /home nor /usr/home is in the base package. > >>> adduser defaults to /home/user, and creates the parent directory (e.g. /home) > >>> if it does not exist, but if there is no internal slash, pw moves the parent > >>> to /usr. In this case, it makes the symlink from root. zfs is different, > >>> in that it includes a usr/home dataset already (created by bsdinstall). I am proposing we fix this. More below. > >>> In this case, creating a user with /home/user causes the symlink to be added > >>> as a side effect. > >>> > >>> I?m sure the kludge was originally done when root and /usr were separate > >>> file systems by default, root was small, and there was no /home by default. > >>> However, we now default to a single large file system (with datasets, in > >>> the zfs case). > >>> > >>> All of this really is a horrible kludge, and it is a house of cards. I'm > >>> amazed that it doesn't break more often. I'm tempted to remove the kludge > >>> and change the zfs setup to create a home dataset rather than usr/home. > > > > Or make it a menu option(s): > > if (zfs) "Create a user home dataset?" (default yes) > > if (ufs) "Create a user home directory?" (default yes) > > Are you suggesting that bsdinstall should do this? For ufs, there is no > need. Yes I am suggesting that bsdinstall should have a knob to turn on (by default) and off the creation of a "home dataset/directory" as you well need that if you choose to add users during a bsdinstall run, or you may not want a /home at all (currently not possible) as you have other mechanisms for dealing with it. The need for this is just as valid for ufs as it is for zfs. > > > "User home location: /home" (This is default) > > Are you proposing that the default for pw should be set at this point? >From all I read the default for pw is already, and should remain /home. Man page bears that out. It has no mention of any symlink or usr/home. > That doesn?t seem necessary, and I don?t know if it would work from > bsdinstall. No, this has nothing to do with pw directly, this is simply the path of the dataset(zfs)/directory(ufs) that bsdinstall should create IFF you sayd yes to the create question. At present this is hardcoded into bsdinstall as: /usr/home /home -> /usr/home I am advocating that this should all be controllable from menu. > > > As far as I am concerned the symlink can just die.... > > I agree, but that requires a change to pw. It creates the symlink on the > first account creation using /home. I am missing something here, pw creates the symlink yuk. As far as I was aware the only think that created a symlink /home -> /usr/home was bsdinstall. > > >>> However, if zfs users explicitly configure a home directory under /usr/home, > >>> this would end up in the usr dataset. An alternative would be to remove the > >>> code from pw to create the parent directory entirely (which seems sensible), > >>> and create a /home directory for ufs installs. I don't know how well known > >>> it is that adduser/pw will create parent directories for home directories > >>> though. This cleanup would change the default location for home directories > >>> to /home, which makes more sense. It would require documentation, e.g. in > >>> the release notes. The changes would only affect new installations, not > >>> upgrades. > >>> > >>> Thoughts? > >>> > >> > >> Adding home would require a change to BSD.root.dist, since it's not > >> currently in there. Only usr is present. > > > > It should *not* be in the etc/mtree/BSD.*.dist files at all. > > And it is not on my 13.1R system. It would not need to be > > in BSD.root.dist either, this is a *post distribution* created > > directory/dataset. > > I?m curious why you think this. But if pw retains the ability to create > the parent directory for the user directory (and I now think it should), > there is no need for a /home by default. Because there is no need for /home in a base distribution until you add a user, and that is a site specific change. What in the base system *needs* /home? > >> IMHO changing pw would be a reasonable approach. > > > > I am mixed on this.... it more or less does the right > > thing, and if a user specifies /tmp/foolishidea/home/$USER > > that is on them. No one said all users homes must be > > in the same location. > > Except for moving parent directories with a single component under /usr, > and creating a symlink for them... > > My current plan is to change pw not to move things under /usr, change the > zfs setup to use a home dataset rather than usr/home (corresponding to the > pw default), and then change the various man pages that refer to /usr/home. > Does that seem reasonable? Yes, then the knobs can easily be added, or scripted install should just work to effect the knobs. > Mike -- Rod Grimes rgrimes@freebsd.org
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