[patch] tsearch.3: dispose properly of allocated resources in example code

[patch] tsearch.3: dispose properly of allocated resources in example code

[André Goddard Rosa]

As there are many users who base their own code on these examples, we should avoid leaking memory when using functions of tsearch() family.
In the provided example, tsearch() leaks memory whenever it tries to insert a number which was already inserted before.

Please CC me, as I´m not subscribed.

Applies to man-pages-3.09.

--- man3/tsearch.3	2008-09-10 10:16:13.000000000 -0300
+++ man3/tsearch.3.goddard	2008-09-21 03:12:43.000000000 -0300
@@ -246,8 +246,11 @@
         val = tsearch((void *) ptr, &root, compare);
         if (val == NULL)
             exit(EXIT_FAILURE);
+        else if ((*(int **) val) != ptr)
+            free(ptr);
     }
     twalk(root, action);
+    tdestroy(root, free);
     exit(EXIT_SUCCESS);
 }
 .fi
\0

[patch] tsearch.3: dispose properly of allocated resources in example code

[André Goddard Rosa]

[-- Attachment #1: Type: text/plain, Size: 743 bytes --]

As there are many users who base their own code on these examples, we should avoid leaking memory when using functions of tsearch() family.
In the provided example, tsearch() leaks memory whenever it tries to insert a number which was already inserted before.

Please CC me, as I´m not subscribed.

Applies to man-pages-3.09.

--- man3/tsearch.3	2008-09-10 10:16:13.000000000 -0300
+++ man3/tsearch.3.goddard	2008-09-21 02:42:55.000000000 -0300
@@ -246,8 +246,11 @@
         val = tsearch((void *) ptr, &root, compare);
         if (val == NULL)
             exit(EXIT_FAILURE);
+        else if (!((*(int **) val) == ptr))
+            free(ptr);
     }
     twalk(root, action);
+    tdestroy(root, free);
     exit(EXIT_SUCCESS);
 }
 .fi
\0

[-- Attachment #2: tsearch3-free-allocated-resources.patch --]
[-- Type: text/x-patch, Size: 414 bytes --]

--- man3/tsearch.3	2008-09-10 10:16:13.000000000 -0300
+++ man3/tsearch.3.goddard	2008-09-21 02:42:55.000000000 -0300
@@ -246,8 +246,11 @@
         val = tsearch((void *) ptr, &root, compare);
         if (val == NULL)
             exit(EXIT_FAILURE);
+        else if (!((*(int **) val) == ptr))
+            free(ptr);
     }
     twalk(root, action);
+    tdestroy(root, free);
     exit(EXIT_SUCCESS);
 }
 .fi

Re: [patch] tsearch.3: dispose properly of allocated resources in example code

[Michael Kerrisk]

André,

On Sun, Sep 21, 2008 at 8:10 AM, André Goddard Rosa
<andre.goddard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> As there are many users who base their own code on these examples, we
> should avoid leaking memory when using functions of tsearch() family.
> In the provided example, tsearch() leaks memory whenever it tries to
> insert a number which was already inserted before.

Thanks.  My first patch applied via 'git am'!

I applied this patch for man-pages-3.10.  (I added
#define _GNU_SOURCE
since that's required to expose the tdestroy() declaration.)

Cheers,

Michael

> --- man3/tsearch.3      2008-09-10 10:16:13.000000000 -0300
> +++ man3/tsearch.3.goddard      2008-09-21 02:42:55.000000000 -0300
> @@ -246,8 +246,11 @@
>         val = tsearch((void *) ptr, &root, compare);
>         if (val == NULL)
>             exit(EXIT_FAILURE);
> +        else if (!((*(int **) val) == ptr))
> +            free(ptr);
>     }
>     twalk(root, action);
> +    tdestroy(root, free);
>     exit(EXIT_SUCCESS);
>  }
>  .fi
>
>



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
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Re: [patch] tsearch.3: dispose properly of allocated resources in example code

[André Goddard Rosa]

On Tue, Sep 23, 2008 at 3:28 AM, Michael Kerrisk
<mtk.manpages-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org> wrote:
> André,
>
> On Sun, Sep 21, 2008 at 8:10 AM, André Goddard Rosa
> <andre.goddard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> As there are many users who base their own code on these examples, we
>> should avoid leaking memory when using functions of tsearch() family.
>> In the provided example, tsearch() leaks memory whenever it tries to
>> insert a number which was already inserted before.
>
> Thanks.  My first patch applied via 'git am'!
>
> I applied this patch for man-pages-3.10.  (I added
> #define _GNU_SOURCE
> since that's required to expose the tdestroy() declaration.)
>

Hi, Michael!

    Very nice, thank you! Good to know that you're using git.

    I appreciate your work in the man pages, they were improved a lot
since you've started working on them. Also, I appreciate your concerns
regarding paccept().

    Notice that I sent two different patches in a sequence (sorry for that).

This is the first one:

> +        else if (!((*(int **) val) == ptr))

and this is the second one:

+        else if ((*(int **) val) != ptr)

    They work the same, but second is cleaner and simpler ;-)

Kind regards,
-- 
[]s,
André Goddard
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Re: [patch] tsearch.3: dispose properly of allocated resources in example code

[Michael Kerrisk]

André,

On Tue, Sep 23, 2008 at 3:23 PM, André Goddard Rosa
<andre.goddard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Tue, Sep 23, 2008 at 3:28 AM, Michael Kerrisk
> <mtk.manpages-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org> wrote:
>> André,
>>
>> On Sun, Sep 21, 2008 at 8:10 AM, André Goddard Rosa
>> <andre.goddard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>> As there are many users who base their own code on these examples, we
>>> should avoid leaking memory when using functions of tsearch() family.
>>> In the provided example, tsearch() leaks memory whenever it tries to
>>> insert a number which was already inserted before.
>>
>> Thanks.  My first patch applied via 'git am'!
>>
>> I applied this patch for man-pages-3.10.  (I added
>> #define _GNU_SOURCE
>> since that's required to expose the tdestroy() declaration.)
>>
>
> Hi, Michael!
>
>    Very nice, thank you! Good to know that you're using git.

(At last... '-).)

>    I appreciate your work in the man pages, they were improved a lot
> since you've started working on them.

Thanks!

> Also, I appreciate your concerns
> regarding paccept().
>
>    Notice that I sent two different patches in a sequence (sorry for that).

It's a good thing you mentioned this, since I did _not_ notice that:
you sent two mails at almost the same, with the same description, and
which looked otherwise identical (unless one looked very close), so I
assumed you had accidentally sent the same mail twice.  (Best to
change the description a little so I know you are resending a
different patch.)

> This is the first one:
>
>> +        else if (!((*(int **) val) == ptr))
>
> and this is the second one:
>
> +        else if ((*(int **) val) != ptr)
>
>    They work the same, but second is cleaner and simpler ;-)

Okay -- I've fixed the page to use the second version.  And you only
just got that one in in time for 3.10!

Thanks,

Michael
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