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Re: [PATCH][BZ #16046] Static dlopen correction fallout fixes
- From: "Maciej W. Rozycki" <macro at codesourcery dot com>
- To: Roland McGrath <roland at hack dot frob dot com>
- Cc: Allan McRae <allan at archlinux dot org>, Ondřej Bílka <neleai at seznam dot cz>, <libc-alpha at sourceware dot org>
- Date: Fri, 20 Jun 2014 21:55:04 +0100
- Subject: Re: [PATCH][BZ #16046] Static dlopen correction fallout fixes
- Authentication-results: sourceware.org; auth=none
- References: <20131017174710 dot GA4993 at domone dot podge> <20131025210328 dot 39E69746B6 at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1310252347350 dot 12843 at tp dot orcam dot me dot uk> <20140116203847 dot GB20838 at domone dot podge> <alpine dot DEB dot 1 dot 10 dot 1401172303320 dot 4268 at tp dot orcam dot me dot uk> <20140117233957 dot 64E307441B at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1401271320170 dot 4268 at tp dot orcam dot me dot uk> <alpine dot DEB dot 1 dot 10 dot 1401291054290 dot 4268 at tp dot orcam dot me dot uk> <20140129184954 dot 1BFFA74441 at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1401300707090 dot 4268 at tp dot orcam dot me dot uk> <20140130203835 dot EB0A874414 at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1401311837460 dot 4268 at tp dot orcam dot me dot uk> <20140131192948 dot 2F8A774430 at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1402031304160 dot 18199 at tp dot orcam dot me dot uk> <20140203175942 dot 7CA1074411 at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1402061659270 dot 18199 at tp dot orcam dot me dot uk> <20140206221305 dot 052D574443 at topped-with-meat dot com>
On Thu, 6 Feb 2014, Roland McGrath wrote:
> (The union hack was in fact wrong pedantically.)
>
> As it's adding a test for code changed in this cycle, I think it should go
> in before the branch.
It didn't happen as I didn't make it before the branch was created. I
have committed it now; as it's been a while below is the patch and the
original explanation again. I'm not sure if it's worth backporting to
2.19, probably not as it doesn't affect functionality (but let me know if
you think otherwise).
Maciej
----------------------------------------------------------------------------
Thinking more about the test case I have concluded that maybe a
path-of-least-resistance check like below would do. It verifies that
there's exactly one link map whose file name is null, as is the case with
the main executable only. This approach may not be particularly robust,
but it does cover what BZ #16046 is about.
2014-01-31 Maciej W. Rozycki <macro@codesourcery.com>
[BZ #16046]
* elf/tst-dl-iter-static.c: New file.
* elf/Makefile (tests-static): Add tst-dl-iter-static.
glibc-static-dlopen-16046-test.diff
Index: glibc-fsf-trunk-quilt/elf/Makefile
===================================================================
--- glibc-fsf-trunk-quilt.orig/elf/Makefile 2014-05-16 03:26:41.411962497 +0100
+++ glibc-fsf-trunk-quilt/elf/Makefile 2014-05-16 03:26:43.411965765 +0100
@@ -121,7 +121,7 @@ tests = tst-tls1 tst-tls2 tst-tls9 tst-l
tst-auxv
tests-static = tst-tls1-static tst-tls2-static tst-stackguard1-static \
tst-leaks1-static tst-array1-static tst-array5-static \
- tst-ptrguard1-static
+ tst-ptrguard1-static tst-dl-iter-static
ifeq (yes,$(build-shared))
tests-static += tst-tls9-static
tst-tls9-static-ENV = \
Index: glibc-fsf-trunk-quilt/elf/tst-dl-iter-static.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ glibc-fsf-trunk-quilt/elf/tst-dl-iter-static.c 2014-05-16 03:26:43.411965765 +0100
@@ -0,0 +1,47 @@
+/* BZ #16046 dl_iterate_phdr static executable test.
+ Copyright (C) 2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <link.h>
+
+/* Check that the link map of the static executable itself is iterated
+ over exactly once. */
+
+static int
+callback (struct dl_phdr_info *info, size_t size, void *data)
+{
+ int *count = data;
+
+ if (info->dlpi_name[0] == '\0')
+ (*count)++;
+
+ return 0;
+}
+
+static int
+do_test (void)
+{
+ int count = 0;
+ int status;
+
+ status = dl_iterate_phdr (callback, &count);
+
+ return status || count != 1;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"