Re: repeated system mail, /etc/.pwd.lock ?

From	David Wright <deblis@lionunicorn.co.uk>
Newsgroups	linux.debian.user
Subject	Re: repeated system mail, /etc/.pwd.lock ?
Date	2021-05-06 05:30 +0200
Message-ID	<CbCS5-7Io-1@gated-at.bofh.it> (permalink)
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On Wed 05 May 2021 at 12:01:07 (-0400), Greg Wooledge wrote:
> On Wed, May 05, 2021 at 10:36:53AM -0500, David Wright wrote:
> > OTOH perhaps monkeysphere has some reason to lock /etc/passwd et al
> > during operation. Running strings on its binaries might throw up
> > some 'pwd.lock' matches. Or one could inotifywatch the program to
> > see how often it is run (unless it's a daemon). Just thinking aloud.
> 
> I actually looked for that filename in "strings /usr/bin/sudo" and
> "strings /usr/sbin/vipw" before Google told me that it's used by those
> libc functions (lckpwdf(3) and its buddy ulckpwdf(3)).
> 
> It's a bit odd that the man page doesn't contain the filename.  Usually
> you'd expect it to.
> 
> > One thing I didn't learn is why .pwd.lock is in /etc/ rather than,
> > say, /run/lock/. Perhaps related, why are there dotfiles in /etc/
> > anyway. (.git/, .java/, .etckeeper, .gitignore are the others.)
> > What are they hiding from?
> 
> This predates /run by a long time.
> 
> Also, presumably, it wants to be in /etc because that's where the file
> that it's paired with lives.  Dot-lock files are usually in the same
> location as the files they represent.

Yes—though its name, in fact, ensures that it never lists next to any
of the files that it might be assumed to lock.

> Why the dot?  So that it doesn't show up in a casual "ls" and cause a
> bunch of n00b questions, obviously.

Yes, I can understand that for the users' home directories; they don't
want listings of their own files to be interspersed with configuration
files. And many of the latter files will be read and written on behalf
of the user rather than by themselves, so there's little need for them
to see them all the time.

But /etc isn't anybody's home directory: it's configuration information
for the whole system. So there's no need to dot any of the files and
directories in order to either inform the sysadmin that these are
configuration files, or to hide them. Anyway, that was my (related) point.

Cheers,
David.

Thread

repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-04 08:20 +0200
  Re: repeated system mail, /etc/.pwd.lock ? Darac Marjal <mailinglist@darac.org.uk> - 2021-05-04 10:10 +0200
    Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-04 10:20 +0200
    Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-04 11:20 +0200
      Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 00:50 +0200
      Re: repeated system mail, /etc/.pwd.lock ? Kushal Kumaran <kushal@locationd.net> - 2021-05-05 03:10 +0200
        Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 03:20 +0200
          Re: repeated system mail, /etc/.pwd.lock ? Greg Wooledge <greg@wooledge.org> - 2021-05-05 03:40 +0200
          Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 04:40 +0200
          Re: repeated system mail, /etc/.pwd.lock ? David Wright <deblis@lionunicorn.co.uk> - 2021-05-05 04:40 +0200
            Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 04:50 +0200
              Re: repeated system mail, /etc/.pwd.lock ? David Wright <deblis@lionunicorn.co.uk> - 2021-05-05 05:10 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 05:20 +0200
            Re: repeated system mail, /etc/.pwd.lock ? Greg Wooledge <greg@wooledge.org> - 2021-05-05 13:30 +0200
              Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 16:00 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Jonathan Dowland <jon+debian-user@dow.land> - 2021-05-08 09:30 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-09 05:10 +0200
              Re: repeated system mail, /etc/.pwd.lock ? David Wright <deblis@lionunicorn.co.uk> - 2021-05-05 17:40 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 18:00 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Greg Wooledge <greg@wooledge.org> - 2021-05-05 18:10 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-05 21:30 +0200
                Re: repeated system mail, /etc/.pwd.lock ? David Wright <deblis@lionunicorn.co.uk> - 2021-05-06 05:30 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Charles Curley <charlescurley@charlescurley.com> - 2021-05-06 04:50 +0200
                Re: repeated system mail, /etc/.pwd.lock ? davidson <davidson@freevolt.org> - 2021-05-06 16:00 +0200
                OT: dotfile generalities (was Re: repeated system mail, /etc/.pwd.lock  ?) davidson <davidson@freevolt.org> - 2021-05-06 16:40 +0200
                Re: OT: dotfile generalities (was Re: repeated system mail,  /etc/.pwd.lock ?) Greg Wooledge <greg@wooledge.org> - 2021-05-06 16:50 +0200
                Re: OT: dotfile generalities (was Re: repeated system mail,  /etc/.pwd.lock ?) David Wright <deblis@lionunicorn.co.uk> - 2021-05-07 06:30 +0200
                Re: OT: dotfile generalities (was Re: repeated system mail,  /etc/.pwd.lock ?) <tomas@tuxteam.de> - 2021-05-07 09:40 +0200
                Re: OT: dotfile generalities (was Re: repeated system mail,  /etc/.pwd.lock ?) Tixy <tixy@yxit.co.uk> - 2021-05-07 10:50 +0200
                Re: OT: dotfile generalities (was Re: repeated system mail,  /etc/.pwd.lock ?) <tomas@tuxteam.de> - 2021-05-07 11:20 +0200
              Re: repeated system mail, /etc/.pwd.lock ? David Wright <deblis@lionunicorn.co.uk> - 2021-05-09 06:20 +0200
                Re: repeated system mail, /etc/.pwd.lock ? Emanuel Berg <moasenwood@zoho.eu> - 2021-05-09 12:00 +0200

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