Re: [PATCH] Fix NULL checking in check_TSCurrentConfig()

Lists: pgsql-hackers
From: Xi Wang <xi(dot)wang(at)gmail(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Cc: Xi Wang <xi(dot)wang(at)gmail(dot)com>
Subject: [PATCH] Fix NULL checking in check_TSCurrentConfig()
Date: 2013-01-20 04:51:26
Message-ID: 1358657486-32676-1-git-send-email-xi.wang@gmail.com
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The correct NULL check should use `*newval'; `newval' must be non-null.
---
src/backend/utils/cache/ts_cache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/backend/utils/cache/ts_cache.c b/src/backend/utils/cache/ts_cache.c
index e688b1a..65a8ad7 100644
--- a/src/backend/utils/cache/ts_cache.c
+++ b/src/backend/utils/cache/ts_cache.c
@@ -642,7 +642,7 @@ check_TSCurrentConfig(char **newval, void **extra, GucSource source)
free(*newval);
*newval = strdup(buf);
pfree(buf);
- if (!newval)
+ if (!*newval)
return false;
}

--
1.7.10.4

From: "Dickson S(dot) Guedes" <listas(at)guedesoft(dot)net>
To: Xi Wang <xi(dot)wang(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Fix NULL checking in check_TSCurrentConfig()
Date: 2013-01-20 14:48:16
Message-ID: CAHHcrermpVwAFcheRkPyVO6pNb6cmHzHE4YzCA3eq5-Zdzh7HA@mail.gmail.com
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2013/1/20 Xi Wang <xi(dot)wang(at)gmail(dot)com>:
> The correct NULL check should use `*newval'; `newval' must be non-null.

[... cutting code ...]

Please see [1] to know how is our submit patch process.

[1] http://wiki.postgresql.org/wiki/Submitting_a_Patch

regards,
--
Dickson S. Guedes
mail/xmpp: guedes(at)guedesoft(dot)net - skype: guediz
http://github.com/guedes - http://guedesoft.net
http://www.postgresql.org.br

From: Stephen Frost <sfrost(at)snowman(dot)net>
To: Xi Wang <xi(dot)wang(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Fix NULL checking in check_TSCurrentConfig()
Date: 2013-01-20 15:39:53
Message-ID: 20130120153952.GL16126@tamriel.snowman.net
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* Xi Wang (xi(dot)wang(at)gmail(dot)com) wrote:
> The correct NULL check should use `*newval'; `newval' must be non-null.

Why isn't this using pstrdup()..?

Thanks,

Stephen

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Stephen Frost <sfrost(at)snowman(dot)net>
Cc: Xi Wang <xi(dot)wang(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Fix NULL checking in check_TSCurrentConfig()
Date: 2013-01-21 03:34:21
Message-ID: 6073.1358739261@sss.pgh.pa.us
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Stephen Frost <sfrost(at)snowman(dot)net> writes:
> * Xi Wang (xi(dot)wang(at)gmail(dot)com) wrote:
>> The correct NULL check should use `*newval'; `newval' must be non-null.

> Why isn't this using pstrdup()..?

The GUC API uses malloc, mainly because guc.c can't afford to lose
control on out-of-memory situations.

regards, tom lane

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Xi Wang <xi(dot)wang(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Fix NULL checking in check_TSCurrentConfig()
Date: 2013-01-21 03:35:45
Message-ID: 6109.1358739345@sss.pgh.pa.us
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Xi Wang <xi(dot)wang(at)gmail(dot)com> writes:
> The correct NULL check should use `*newval'; `newval' must be non-null.

Great catch, will commit. (But first I'm looking through commit
2594cf0e to see if I made the same mistake anywhere else :-(.)

How did you find that, coverity or some such tool?

regards, tom lane

From: Xi Wang <xi(dot)wang(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: [PATCH] Fix NULL checking in check_TSCurrentConfig()
Date: 2013-01-21 08:35:29
Message-ID: 50FCFDD1.1070609@gmail.com
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On 1/20/13 10:35 PM, Tom Lane wrote:
> Great catch, will commit. (But first I'm looking through commit
> 2594cf0e to see if I made the same mistake anywhere else :-(.)
>
> How did you find that, coverity or some such tool?

Thanks for reviewing the patch.

It was found using a homemade static undefined behavior checker.

- xi