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Bug 589056 - review of patches addressing memory leaks in libtar
Summary: review of patches addressing memory leaks in libtar
Alias: None
Product: Fedora
Classification: Fedora
Component: libtar
Version: rawhide
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Kamil Dudka
QA Contact: Fedora Extras Quality Assurance
Depends On:
Blocks: 595635
TreeView+ depends on / blocked
Reported: 2010-05-05 09:23 UTC by Kamil Dudka
Modified: 2010-05-27 14:16 UTC (History)
2 users (show)

Fixed In Version: libtar-1.2.11-19.fc14
Doc Type: Bug Fix
Doc Text:
Clone Of:
: 595635 (view as bug list)
Last Closed: 2010-05-27 14:16:41 UTC

Attachments (Terms of Use)
patch #1 (deleted)
2010-05-05 09:26 UTC, Kamil Dudka
no flags Details | Diff
patch #2 (deleted)
2010-05-05 09:27 UTC, Kamil Dudka
no flags Details | Diff
revisited patch (deleted)
2010-05-25 08:57 UTC, Kamil Dudka
no flags Details | Diff
revisited patch V2 (deleted)
2010-05-27 09:18 UTC, Kamil Dudka
huzaifas: review+
Details | Diff
revisited patch V2 (deleted)
2010-05-27 09:20 UTC, Kamil Dudka
no flags Details | Diff

Description Kamil Dudka 2010-05-05 09:23:20 UTC
Patches contributed by Huzaifa Sidhpurwala.

Version-Release number of selected component (if applicable):

Comment 1 Kamil Dudka 2010-05-05 09:26:32 UTC
Created attachment 411524 [details]
patch #1

I only removed two unintentional hunks removing the <stdlib.h> include.

Comment 2 Kamil Dudka 2010-05-05 09:27:37 UTC
Created attachment 411525 [details]
patch #2

Comment 3 Huzaifa S. Sidhpurwala 2010-05-05 09:29:20 UTC
Patches work, stdlib removal was non-intentional though

Comment 4 Kamil Dudka 2010-05-05 10:38:15 UTC
Comment on attachment 411524 [details]
patch #1

>@@ -29,7 +29,7 @@ th_get_pathname(TAR *t)
> 	char filename[MAXPATHLEN];

We agreed with Huzaifa that making the 'filename' static would lead to easier code since all the strdup/free would be no more necessary.

>@@ -92,10 +92,6 @@ gzopen_frontend(char *pathname, int oflags, int mode)
> 		return -1;
> 	}
>-	/* This is a bad thing to do on big-endian lp64 systems, where the
>-	   size and placement of integers is different than pointers.
>-	   However, to fix the problem 4 wrapper functions would be needed and
>-	   an extra bit of data associating GZF with the wrapper functions.  */

As the comment still seems to be relevant, we may keep it there.

Comment 5 Kamil Dudka 2010-05-05 10:42:00 UTC
Comment on attachment 411525 [details]
patch #2

>@@ -245,7 +245,12 @@ extract(char *tarfile, char *rootdir)
> #endif
> 	if (tar_extract_all(t, rootdir) != 0)
> 	{
> 		fprintf(stderr, "tar_extract_all(): %s\n", strerror(errno));
>+		if (t->h)
>+			libtar_hash_free(t->h,NULL);
>+		if (t)		
>+			free (t);

The second condition can be never evaluated as false.  I suggest something like this:

    if (t)
        if (t->h)

        free (t);

>@@ -255,6 +260,10 @@ extract(char *tarfile, char *rootdir)
> 	if (tar_close(t) != 0)
> 	{
> 		fprintf(stderr, "tar_close(): %s\n", strerror(errno));
>+		if (t->h)
>+			libtar_hash_free(t->h, NULL);
>+		if (t)
>+			free (t);

The same here.

Overall the patches look good.  Thank you for working on them!

Comment 6 Kamil Dudka 2010-05-25 08:57:33 UTC
Created attachment 416325 [details]
revisited patch

I've just put the patches together and addressed the review comments.

Huzaifa, could you please have a look whether it still works fine for you?

Thanks in advance!

Comment 7 Kamil Dudka 2010-05-26 13:02:37 UTC
Comment on attachment 416325 [details]
revisited patch

Looking once again, I considered use of the static array as really bad idea.  It would work fairly well in tar(1), but not so well in a library which may be used from a multi-threaded environment.

Comment 8 Kamil Dudka 2010-05-27 09:18:34 UTC
Created attachment 417159 [details]
revisited patch V2

reverted the static array change and fixed some other memory leaks in libtar.c

Comment 9 Kamil Dudka 2010-05-27 09:20:49 UTC
Created attachment 417160 [details]
revisited patch V2

reverted the static array change and fixed some other memory leaks in libtar.c

Comment 10 Kamil Dudka 2010-05-27 09:23:11 UTC
Comment on attachment 417160 [details]
revisited patch V2

Oops, race condition.  No reason the have the same patch twice here...

Comment 11 Kamil Dudka 2010-05-27 14:16:41 UTC
built as libtar-1.2.11-19.fc14

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