[Pgpool-hackers] Reload does not help if password file changed

[Gurjeet Singh]

Thanks for the correcting the mistakes. Although I think the stack-frame of
main() function is always available to all the functions that come after it,
hence using a stack variable from that frame wouldn't have hurt, but I agree
with the change because it avoids any future confusion.

Also, would it be possible to back-patch this to previous stable versions?
As my earlier complaints, I wouldn't treat this as new feature, but a bug
which always got overlooked, because SIGHUP is always supposed to reload the
config files and yet password changes were never updated. My 2 cents.

Regards,

On Thu, Sep 29, 2011 at 4:47 AM, Tatsuo Ishii <ishii at sraoss.co.jp> wrote:

> Hi Gurjeet,
>
> I have committed your patches to CVS HEAD with my minor editings. It's
> great that we don't need to restart pgpool-II each time user changed
> md5 password!
>
> Here are my slight changes to original patch:
>
> - Checking pool_config->pool_passwd is not correct way to judge if we
>  need to reopen pool_passwd or not. Rather you should look into
>  enable_pool_hba. Because pool_config->pool_passwd is the base file
>  name of pool_passwd(can be used if you want to change standard
>  "pool_passwd"), and md5 auth is not enabled if enable_pool_hba is
>  off.
>
> - Storing pointer to pool_passwd path will not work since the body is
>  located at a stack area(char pool_passwd[POOLMAXPATHLEN+1] around
>  line 425 of mainc.). I modify to copy it to static memory.
>
> Chinese, French and German doc maintainer:
>
> I have modified documentation around line 3279 of
> pgpool-en.html. Please update other language. Thanks in advance.
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese: http://www.sraoss.co.jp
>
> > Hi Gurjeet,
> >
> > Sorry for delay.
> > I will take care of this tomorrow.
> > --
> > Tatsuo Ishii
> > SRA OSS, Inc. Japan
> > English: http://www.sraoss.co.jp/index_en.php
> > Japanese: http://www.sraoss.co.jp
> >
> >> Hi Tatsuo,
> >>
> >>     Any feedback on the correctness of the patch?
> >>
> >> Thanks,
> >>
> >> On Mon, Sep 26, 2011 at 10:18 PM, Gurjeet Singh <
> singh.gurjeet at gmail.com>wrote:
> >>
> >>> Hi Tatsuo,
> >>>
> >>>     Please find an updated patch. I am now using strcmp() to check if
> we
> >>> need to reopne the file, just like the code in main.c, instead of
> comparing
> >>> the value with NULL.
> >>>
> >>> Regards,
> >>>
> >>>
> >>> On Mon, Sep 26, 2011 at 9:57 PM, Tatsuo Ishii <ishii at sraoss.co.jp>
> wrote:
> >>>
> >>>> Thanks for report and patches. I will take care of this.
> >>>> --
> >>>> Tatsuo Ishii
> >>>> SRA OSS, Inc. Japan
> >>>> English: http://www.sraoss.co.jp/index_en.php
> >>>> Japanese: http://www.sraoss.co.jp
> >>>>
> >>>> > Hi,
> >>>> >
> >>>> >     Maybe this is expected behaviour, but it definitely is not
> >>>> desirable. If
> >>>> > we add a new user:passwrod to the contents of pool_passwd file and
> send
> >>>> a
> >>>> > reload signal to pgpool, the child processes are still not able to
> honor
> >>>> the
> >>>> > new user and the trying to login using the new user causes error
> "MD5
> >>>> > authentication failed..."
> >>>> >
> >>>> >     I have diagnosed it back to the fact that pgpool uses stdio.h
> >>>> interface
> >>>> > (FILE *) to access the pool_passwd file, and it reads the contents
> of
> >>>> the
> >>>> > file for every new login that requests MD5 authentication. The
> problem
> >>>> with
> >>>> > the stdio.h interface is that it caches the contents of the file and
> it
> >>>> does
> >>>> > not refresh the cache even when the contents of the file change
> on-disk,
> >>>> so
> >>>> > every time pgpool tries to read new user's password it does not see
> the
> >>>> new
> >>>> > entry and hence fails.
> >>>> >
> >>>> >     To be able to connect as the new user we have to either restart
> >>>> pgpool
> >>>> > or wait for a new child to be forked which will see the new contents
> of
> >>>> the
> >>>> > file. All of these problems also apply to the case where we might
> alter
> >>>> the
> >>>> > password of an existing user and update the md5 password in
> pool_passwd
> >>>> > file.
> >>>> >
> >>>> >     I have attached a minimal patch to address this issue. In the
> patch,
> >>>> we
> >>>> > save the file path that was initially used to open the pool_passwd
> and
> >>>> upon
> >>>> > every reload the child closes and reopens the file so that the
> stdio.h
> >>>> > interface does not show it cached data.
> >>>> >
> >>>> > Regards,
> >>>> > --
> >>>> > Gurjeet Singh
> >>>> > EnterpriseDB Corporation
> >>>> > The Enterprise PostgreSQL Company
> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> Gurjeet Singh
> >>> EnterpriseDB Corporation
> >>> The Enterprise PostgreSQL Company
> >>>
> >>>
> >>
> >>
> >> --
> >> Gurjeet Singh
> >> EnterpriseDB Corporation
> >> The Enterprise PostgreSQL Company
> > _______________________________________________
> > Pgpool-hackers mailing list
> > Pgpool-hackers at pgfoundry.org
> > http://pgfoundry.org/mailman/listinfo/pgpool-hackers
>



-- 
Gurjeet Singh
EnterpriseDB Corporation
The Enterprise PostgreSQL Company
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