GNU bug report logs - #47384
[PATCH 1/2] hostname: fix a memory leak with -Dlint

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Kamil Dudka <kdudka <at> redhat.com>
To: bug-coreutils <at> gnu.org
Subject: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 11:57:55 +0100

* src/hostname.c (main): Free allocated memory when compiled
with -Dlint.
---
 src/hostname.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/hostname.c b/src/hostname.c
index 7d13575d4e9..8ec9aad4d34 100644
--- a/src/hostname.c
+++ b/src/hostname.c
@@ -104,6 +104,9 @@ main (int argc, char **argv)
       if (hostname == NULL)
         die (EXIT_FAILURE, errno, _("cannot determine hostname"));
       printf ("%s\n", hostname);
+#ifdef lint
+      free(hostname);
+#endif
     }
 
   if (optind + 1 < argc)
-- 
2.26.3

Message #8 received at 47384 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Kamil Dudka <kdudka <at> redhat.com>
Cc: 47384 <at> debbugs.gnu.org
Subject: Re: bug#47384: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 08:56:15 -0700

On 3/25/21 3:57 AM, Kamil Dudka wrote:

> +#ifdef lint
> +      free(hostname);
> +#endif

Let's not do this one. The program is about to exit so there's no need 
to free, and any static-checking tool that complains about a missing 
'free' here is issuing a false alarm. On this particular issue it's 
better to fix the tools than to clutter upb source code to pacify them.

Message #11 received at 47384 <at> debbugs.gnu.org (full text, mbox):

From: Kamil Dudka <kdudka <at> redhat.com>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 47384 <at> debbugs.gnu.org, bug-coreutils <at> gnu.org
Subject: Re: bug#47384: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 17:08:50 +0100

On Thursday, March 25, 2021 4:56:15 PM CET Paul Eggert wrote:
> On 3/25/21 3:57 AM, Kamil Dudka wrote:
> > +#ifdef lint
> > +      free(hostname);
> > +#endif
> 
> Let's not do this one. The program is about to exit so there's no need
> to free, and any static-checking tool that complains about a missing
> 'free' here is issuing a false alarm. On this particular issue it's
> better to fix the tools than to clutter upb source code to pacify them.

Wasn't that exactly what -Dlint was for when we discussed it the last time?
I am totally lost in your reasoning again.  But thank you for having a look.

Kamil

Message #17 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Kamil Dudka <kdudka <at> redhat.com>
Cc: 47384 <at> debbugs.gnu.org, bug-coreutils <at> gnu.org
Subject: Re: bug#47384: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 09:09:44 -0700

On 3/25/21 9:08 AM, Kamil Dudka wrote:
> Wasn't that exactly what -Dlint was for when we discussed it the last time?

Sorry, don't recall the last time. This is a borderline area, admittedly.

Message #23 received at 47384 <at> debbugs.gnu.org (full text, mbox):

From: Kamil Dudka <kdudka <at> redhat.com>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 47384 <at> debbugs.gnu.org, bug-coreutils <at> gnu.org
Subject: Re: bug#47384: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 17:33:50 +0100

On Thursday, March 25, 2021 5:09:44 PM CET Paul Eggert wrote:
> On 3/25/21 9:08 AM, Kamil Dudka wrote:
> > Wasn't that exactly what -Dlint was for when we discussed it the last
> > time?
> 
> Sorry, don't recall the last time.

I meant this thread on bug-gnulib ML:

    https://lists.gnu.org/archive/html/bug-gnulib/2020-05/msg00114.html

> This is a borderline area, admittedly.

How does it differ from the following change, which you did not block?

    https://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=v8.24-21-ga4b640549df

Kamil

Message #29 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Kamil Dudka <kdudka <at> redhat.com>
Cc: 47384 <at> debbugs.gnu.org, bug-coreutils <at> gnu.org
Subject: Re: bug#47384: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 11:16:46 -0700

On 3/25/21 9:33 AM, Kamil Dudka wrote:
> How does it differ from the following change, which you did not block?

Thanks for reminding me of the earlier exchange. On second thought I 
guess it's OK, though I'd prefer it to use IF_LINT (as in the earlier 
change), as that makes it cleaner since it's just one line of useless 
code, not three.

Message #37 received at 47384-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Kamil Dudka <kdudka <at> redhat.com>
Cc: 47384-done <at> debbugs.gnu.org
Subject: Re: bug#47384: [PATCH 1/2] hostname: fix a memory leak with -Dlint
Date: Thu, 25 Mar 2021 11:22:33 -0700

[Message part 1 (text/plain, inline)]

On 3/25/21 11:16 AM, Paul Eggert wrote:
> I'd prefer it to use IF_LINT (as in the earlier 
> change), as that makes it cleaner since it's just one line of useless 
> code, not three.

Installed as attached, and closing the bug report. Thanks again.

[0001-hostname-pacify-valgrind.patch (text/x-patch, attachment)]

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