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Date:      Sun, 5 May 2013 10:42:02 +0430
From:      takCoder <tak.official@gmail.com>
To:        Polytropon <freebsd@edvax.de>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: pwd.db/spwd.db file corupption when having unsafe system poweroff
Message-ID:  <CAPkyVLwJK2sNLof4MWahX30GK1aGskkMFWMhvBys4ND+abQSnw@mail.gmail.com>
In-Reply-To: <20130501110147.c69f408b.freebsd@edvax.de>
References:  <CAHHq+VwcazbVXDDsZqH1AXxVOu0mfGjT_5Tcj3OoHJroe8Kgdg@mail.gmail.com> <kkkda5$vm9$1@ger.gmane.org> <20130417173544.25266cd6.freebsd@edvax.de> <CAPkyVLwPg6xPy6rHZ6kqTLcum77vg-QnLhHmFEmPvXhG40QSsQ@mail.gmail.com> <CAPkyVLzaHkL5FFVhdFw60HnhYZ3GUn696z5NbTCoPVxfFCGrmA@mail.gmail.com> <20130501110147.c69f408b.freebsd@edvax.de>

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First, thank you for your quick and complete reply :)

then:


> Furthermore, file system corruption due to an abrupt
> cut of power should be avoided. Whenever the system comes
> up in a non-clean state, fsck should be run first, _then_
> the boot process should continue. Still it's possible that
> this process leaves truncated files behind (e. g. the
> binary database files with a length of zero, which implies
> they will have to be rebuilt by pwd_mkdb).
>
> i added fsck_background=no to rc.conf but i still see the error.. and i
don't see any differance in system startup output! how should i know it's
working??


> Alternatively to pw, you could try adduser, which is more
> an interactive program, but can perform the same tasks.
> Again, it would take care of updating all required files.
> This is the situation one would expect after the program
> ended, or at least some seconds after one got back to the
> root prompt.
>
when i tried using adduser, when a error occurs(like multiple definition of
a username), it's pw who reports the errors! it means that adduser also
uses pw.. is this functionality of "taking care of updating all required
files", an add-on appeared in add-user??


> During the 2 minutes, you could use programs like lsof
> (it's in ports) to check if a program has a file open,
> so you could capture the "power off while writing to
> file" incident.
>
i tried using lsof as well , but there was no differance.. yes! when i use
pw -h 0 parameter, 10 extra files are added to the lsof list.. but exactly
after i enter the password, all of them are closed(none of these files are
of those main 5 files of users..lib files and alike..).. and in later
monitoring with lsof, i could not catch the time when these files are in
use!.. i'll write a shell to monitor it more detailed though..

After you could not login again, did you check the
> files involved in the login process?
>
yes, file sizes are ok but pwd.db and swpd.db are out of use..(also once i
opened passwd with nano and it had irrational characters..). always if i
use pwd_mkdb or just replace these two files, in next startup system will
come up fine!

now there is something special about my own servers, which i'm suspicious
of..
i've add an executable file to my /usr/local/etc/rc.d dir, which tries to
initiate some parts of myserver.. this includes usernames as well.. i mean,
i may have template users during system uptime, which i won't need in next
startup.. this initiliazer will remove those unwanted users and redifine
main usernames, using pw..
it works fine while having safe shutdowns but when i have the bug-generator
scenario, it won't work.. may it be the conflict of running my initializer
and fsck ? or is it true that rc.d files are executed in shutdown process
as well? is shutdown process started when i start pressing power button for
4 seconds??

i don't know what else to think of...



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