Date: Sat, 13 May 2023 15:48:03 -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: <202305132248.34DMm3Yu069553@gndrsh.dnsmgr.net> In-Reply-To: <4DD6D2C9-9F3A-4265-92FA-1B09817634FB@karels.net>
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> On 12 May 2023, at 19:43, Rodney W. Grimes wrote: > > >> Rod and I discussed this, and I?m top-posting a summary of a proposal that > >> we both support. I?ll leave the last message from the list below for > >> reference. Our consensus is that the main problem is the code in pw(8) > >> (used by adduser, and hence bsdinstall) that interprets /home as /usr/home, > >> installing a symlink for /home, and similarly for any other home directory > >> whose parent has a single component. We propose to remove that code, and > >> also modify bsdinstall?s zfs script to create a home dataset rather than > > > > Small nit, zfs already creates the data set as $POOL/usr/home, this > > would change to $POOL/home. > > > >> usr/home. adduser presents a default home directory using /home, so this > >> will continue to agree. As Rod said at the start of this thread, home > >> directories really don?t belong in /usr, and the only reason they were > >> there is because of the previous root + /usr partitioning. Now the default > >> is one large partition. Of course, people who want to partition differently > >> can do whatever they want. > >> > >> It will still be possible for admins to create home directories in > >> /usr/home, they will just have to do so explicitly for pw to create the > >> directory, and manually create a /home symlink if desired. If they have > >> a small root file system, they will want to put home directories elsewhere. > >> > >> A followup change would be to change various man pages that refer to > >> /usr/home. > > The changes are now in review: > > https://reviews.freebsd.org/D40085 pw change to use the specified dir > https://reviews.freebsd.org/D40086 bsdinstall change to create /home > rather than /usr/home dataset on ZFS > Mike Need one more to backout the changes to hier(7)? > > >> On 11 May 2023, at 12:32, Rodney W. Grimes wrote: > >> > >>>> 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 > >> > >> > > > > -- > > Rod Grimes rgrimes@freebsd.org > > -- Rod Grimes rgrimes@freebsd.org
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