Suggested changes to util-linux for FHS compliance.

Suggested changes to util-linux for FHS compliance.

[Bruce Dubbs]

I don't recall if this has come up before, but I suggest a couple of 
changes to the default util-linux build configuuration:

1. Change the default ADJTIME_PATH to be /var/lib/hwclock/adjtime

This would be a one line change to include/pathnames.h:
   # define _PATH_ADJTIME              "/etc/adjtime"

For a reference, see the FHS paragraph 5.8.6:

https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05s08.html#varlibhwclockStateDirectoryForHwclo

Currently this behavior can be done by exporting the environment 
variable ADJTIME_PATH=/var/lib/hwclock/adjtime before running configure, 
but is undocumented except in the 2.25 release notes.

2. Change the references to /var/run to just /run or at least add a 
configure option --runstatedir=<path>.

Most systems today create /run as a tmpfs.  See:

https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s15.html and
https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05s13.html

Currently this change can be manually made by setting an environment 
variable, runstatedir=/run when running configure, but is undocumented.

   -- Bruce Dubbs
      linuxfromscratch.org

Re: Suggested changes to util-linux for FHS compliance.

[Karel Zak]

On Fri, Feb 12, 2021 at 11:04:59AM -0600, Bruce Dubbs wrote:
> I don't recall if this has come up before, but I suggest a couple of changes
> to the default util-linux build configuuration:
> 
> 1. Change the default ADJTIME_PATH to be /var/lib/hwclock/adjtime

Good idea. I'll do that.

> 2. Change the references to /var/run to just /run or at least add a
> configure option --runstatedir=<path>.

The current default is /run if --localstatedir is NONE or /var, see
configure.ac:

 # default for old versions without $runstatedir
 AS_IF([test x"$runstatedir" = x], [runstatedir='${localstatedir}/run'])
 
 # our default if $localstatedir unchanged
 AS_CASE([$localstatedir:$runstatedir],
  [NONE:'${localstatedir}/run' | /var:'${localstatedir}/run' | NONE:'/run' ],
    [runstatedir=/run; AC_MSG_NOTICE([  --runstatedir defaults to /run])]
 )
 
 AC_SUBST([runstatedir])


Try it without an option:

        $ ./configure
        ...
        configure: Default --exec-prefix detected.
        configure:   --bindir defaults to /bin
        configure:   --sbindir defaults to /sbin
        configure:   --libdir defaults to /lib64
        configure:   --runstatedir defaults to /run

the @runstatedir@ should be available since autoconf 2.70
https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
but not sure about the option.

For example for Fedora we use:

        ./configure --build=x86_64-redhat-linux-gnu \
        --host=x86_64-redhat-linux-gnu --program-prefix= \
        --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr \
        --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc \
        --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 \
        --libexecdir=/usr/libexec --localstatedir=/var \
        --sharedstatedir=/var/lib --mandir=/usr/share/man \
        --infodir=/usr/share/info \
        --with-systemdsystemunitdir=/usr/lib/systemd/system \
        --disable-silent-rules --disable-bfs --disable-pg --enable-chfn-chsh  \
        --enable-usrdir-path --enable-write --enable-raw --enable-hardlink \
        --with-python=3 --with-systemd --with-udev --with-selinux --with-audit \
        --with-utempter --disable-makeinstall-chown


and it also defaults to /run because of --localstatedir=/var

> Currently this change can be manually made by setting an environment
> variable, runstatedir=/run when running configure, but is undocumented.

The current default should be already good enough for usual use-cases :-)

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: Suggested changes to util-linux for FHS compliance.

[Bruce Dubbs]

On 2/15/21 3:16 AM, Karel Zak wrote:
> On Fri, Feb 12, 2021 at 11:04:59AM -0600, Bruce Dubbs wrote:
>> I don't recall if this has come up before, but I suggest a couple of changes
>> to the default util-linux build configuuration:
>>
>> 1. Change the default ADJTIME_PATH to be /var/lib/hwclock/adjtime
> 
> Good idea. I'll do that.

Thanks.

Note: Sorry to take so long to reply.  We've been without power/internet 
for three days in Texas.


>> 2. Change the references to /var/run to just /run or at least add a
>> configure option --runstatedir=<path>.
> 
> The current default is /run if --localstatedir is NONE or /var, see
> configure.ac:
> 
>   # default for old versions without $runstatedir
>   AS_IF([test x"$runstatedir" = x], [runstatedir='${localstatedir}/run'])
>   
>   # our default if $localstatedir unchanged
>   AS_CASE([$localstatedir:$runstatedir],
>    [NONE:'${localstatedir}/run' | /var:'${localstatedir}/run' | NONE:'/run' ],
>      [runstatedir=/run; AC_MSG_NOTICE([  --runstatedir defaults to /run])]
>   )
>   
>   AC_SUBST([runstatedir])
> 
> 
> Try it without an option:
> 
>          $ ./configure
>          ...
>          configure: Default --exec-prefix detected.
>          configure:   --bindir defaults to /bin
>          configure:   --sbindir defaults to /sbin
>          configure:   --libdir defaults to /lib64
>          configure:   --runstatedir defaults to /run
> 
> the @runstatedir@ should be available since autoconf 2.70
> https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
> but not sure about the option.

We have autoconf 2.71, but we are not using it for util-linux. The 
standard tarball defaults to [PREFIX/var] for localstatedir and it is 
very common to use --prefix=/usr, so that makes using --localstatedir 
required if runstatedir=/run is desired.

This is an indirect implied result.  Shouldn't it be made explicit?

Perhaps another solution would be to make the default for localstatedir 
be /var instead of PREFIX/var.

For now we are just using the environment variable runstatedir=/run.

   -- Bruce

Re: Suggested changes to util-linux for FHS compliance.

[Karel Zak]

On Thu, Feb 18, 2021 at 09:37:21AM -0600, Bruce Dubbs wrote:
> Perhaps another solution would be to make the default for localstatedir be
> /var instead of PREFIX/var.

Ah, I see what do you mean. 

We do not alter $localstatedir in the configure script at all. This is is 
probably the problem you see. For the other directories we default to /bin,
/lib, ... when the default prefix (NONE or /usr) detected.

It seems $localstatedir and $sysconfdir need our care too.

I have committed:
 
  https://github.com/karelzak/util-linux/commit/3d2899651791bcb4ee8fe4e605acc83f3ae3471b

Please, try it. The final summary from ./configure should be also
more verbose about the paths now.

   Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: Suggested changes to util-linux for FHS compliance.

[Karel Zak]

On Mon, Feb 15, 2021 at 10:16:30AM +0100, Karel Zak wrote:
> On Fri, Feb 12, 2021 at 11:04:59AM -0600, Bruce Dubbs wrote:
> > I don't recall if this has come up before, but I suggest a couple of changes
> > to the default util-linux build configuuration:
> > 
> > 1. Change the default ADJTIME_PATH to be /var/lib/hwclock/adjtime
> 
> Good idea. I'll do that.

Hmm... I remembered now that we have in our TODO:

 hwclock
 ------
 - use /var/lib/hwclock/drift to store hw-clock drift numbers.
 - use /etc/adjtime as read-only for UTC/LOCAL information only
 - the /var/lib/hwclock/drift should be implemented backwardly compatible,
   it means use the file only if exists, otherwise follow /etc/adjtime

so maybe the best would be to keep ADJTIME_PATH=/etc/adjtime and use
it as read-only and use ${localstatedir}/lib/hwclock/drift for the
rest.

Note that ADJTIME_PATH is used by more utils, like rtcwake or systemd,
so move it is not so easy.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: Suggested changes to util-linux for FHS compliance.

[Bruce Dubbs]

On 2/19/21 5:14 AM, Karel Zak wrote:
> On Thu, Feb 18, 2021 at 09:37:21AM -0600, Bruce Dubbs wrote:
>> Perhaps another solution would be to make the default for localstatedir be
>> /var instead of PREFIX/var.
> 
> Ah, I see what do you mean.
> 
> We do not alter $localstatedir in the configure script at all. This is is
> probably the problem you see. For the other directories we default to /bin,
> /lib, ... when the default prefix (NONE or /usr) detected.
> 
> It seems $localstatedir and $sysconfdir need our care too.
> 
> I have committed:
>   
>    https://github.com/karelzak/util-linux/commit/3d2899651791bcb4ee8fe4e605acc83f3ae3471b
> 
> Please, try it. The final summary from ./configure should be also
> more verbose about the paths now.

Thanks Karel.  Works for us.

   -- Bruce

Re: Suggested changes to util-linux for FHS compliance.

[Karel Zak]

On Fri, Feb 19, 2021 at 12:30:12PM +0100, Karel Zak wrote:
> On Mon, Feb 15, 2021 at 10:16:30AM +0100, Karel Zak wrote:
> > On Fri, Feb 12, 2021 at 11:04:59AM -0600, Bruce Dubbs wrote:
> > > I don't recall if this has come up before, but I suggest a couple of changes
> > > to the default util-linux build configuuration:
> > > 
> > > 1. Change the default ADJTIME_PATH to be /var/lib/hwclock/adjtime
> > 
> > Good idea. I'll do that.
> 
> Hmm... I remembered now that we have in our TODO:
> 
>  hwclock
>  ------
>  - use /var/lib/hwclock/drift to store hw-clock drift numbers.
>  - use /etc/adjtime as read-only for UTC/LOCAL information only
>  - the /var/lib/hwclock/drift should be implemented backwardly compatible,
>    it means use the file only if exists, otherwise follow /etc/adjtime
> 
> so maybe the best would be to keep ADJTIME_PATH=/etc/adjtime and use
> it as read-only and use ${localstatedir}/lib/hwclock/drift for the
> rest.
> 
> Note that ADJTIME_PATH is used by more utils, like rtcwake or systemd,
> so move it is not so easy.

OK, I have implemented it, but frankly, I'm not sure about it ;-) 
I have added William to CC:, maybe he will come with comments.  
       
See https://github.com/karelzak/util-linux/tree/topic/hwclock-drift-file
branch.                                                    
       
The idea is to keep /etc/adjtime as a source for UTC/LOCAL flag, but   
hwclock drift info (which we need to update occasionally) move to    
/var/lib/hwclock/drift. The /etc/adjtime is de-facto standard and
move it means that 3rd party utils will have no way how to determine 
hwclock UTC/LOCAL mode.
       
Both files use "adjtime" file format to make it simple to convert
from one to another.                                         
       
The change should be backwardly compatible. If you do not have /var/lib/hwclock/drift 
then it falls back to /etc/adjtime.                                  
       
I'm not sure if this is not over-engineering. Maybe the current
solution is good enough, and all we need is to make it more
use-friendly to set ADJTIME_PATH for users like Bruce (although
maintain any status information in /etc (in the year 2021) is not
nice.


The another possibility is to make a real change. Introduce completely
new file in /etc (/etc/clockmode) with only UTC/LOCAL(, force all
applications to use it (I know about rtcwake and systemd), and keep
/var/lib/hwclock/drift as private hwclock(1) file in a private format.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com