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[1/3] Mark __libc_multiple_libcs with attribute_hidden [BZ #18822]

Message ID CAMe9rOpZ4iF9gAAOpwVUtXsMgY1p_=ZktpptEsSyaCP7Hxm0Fg@mail.gmail.com
State New, archived
Headers show

Commit Message

H.J. Lu Aug. 21, 2017, 11:48 a.m. UTC 
On Mon, Aug 21, 2017 at 4:19 AM, Florian Weimer <fweimer@redhat.com> wrote:
> On 08/21/2017 01:16 PM, H.J. Lu wrote:
>> On Mon, Aug 21, 2017 at 3:03 AM, Florian Weimer <fweimer@redhat.com> wrote:
>>> On 08/20/2017 04:12 PM, H.J. Lu wrote:
>>>> +/* Set nonzero if we have to be prepared for more than one libc being
>>>> +   used in the process.  */
>>>> +extern int __libc_multiple_libcs attribute_hidden;
>>>
>>> I think the comment gives the wrong impression.  The flag is not always
>>> set if there are multiple libcs in the process, and it certainly is not
>>> set just because we might end up having multiple libcs in the future
>>> (which is why the “have to be prepared” part irks me).
>>
>> I copied it from csu/init-first.c:
>>
>> /* Set nonzero if we have to be prepared for more than one libc being
>>    used in the process.  Safe assumption if initializer never runs.  */
>> int __libc_multiple_libcs attribute_hidden = 1;
>
> Ahh, that's only appropriate for this particular definition.
>
>> Should I just leave out the comments?
>
> Yes please, unless someone can describe what the flag actually means (I
> tried to use it in the past, and it did not work reliably with inner libcs).
>

Here is the updated patch.  I will check it in shortly.

Thanks.

Comments

Florian Weimer Aug. 21, 2017, 12:27 p.m. UTC | #1 
On 08/21/2017 01:48 PM, H.J. Lu wrote:
> 	[BZ #18822]
> 	* csu/libc-start.c (__libc_multiple_libcs): Removed.
> 	* elf/dl-open.c: Include <libc-internal.h>.
> 	(__libc_multiple_libcs): Removed.
> 	* elf/dl-sysdep.c: Include <libc-internal.h> instead of
> 	<hp-timing.h>.
> 	* include/libc-internal.h (__libc_multiple_libcs): New.
> 	* misc/sbrk.c: Include <libc-internal.h>.
> 	(__libc_multiple_libcs): Removed.

Okay.

Florian
diff mbox

Patch

From 54b8fdadfb2d6ee877a7cee64ab9b2353c37ecc3 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 18 Aug 2017 12:19:28 -0700
Subject: [PATCH] Mark __libc_multiple_libcs with attribute_hidden [BZ #18822]

Since __libc_multiple_libcs is defined as hidden symbol in init-first.c,
it should be always marked with attribute_hidden.

	[BZ #18822]
	* csu/libc-start.c (__libc_multiple_libcs): Removed.
	* elf/dl-open.c: Include <libc-internal.h>.
	(__libc_multiple_libcs): Removed.
	* elf/dl-sysdep.c: Include <libc-internal.h> instead of
	<hp-timing.h>.
	* include/libc-internal.h (__libc_multiple_libcs): New.
	* misc/sbrk.c: Include <libc-internal.h>.
	(__libc_multiple_libcs): Removed.
---
 csu/libc-start.c        | 2 --
 elf/dl-open.c           | 3 +--
 elf/dl-sysdep.c         | 2 +-
 include/libc-internal.h | 2 ++
 misc/sbrk.c             | 4 +---
 5 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/csu/libc-start.c b/csu/libc-start.c
index 6720617188..24c63be02f 100644
--- a/csu/libc-start.c
+++ b/csu/libc-start.c
@@ -27,8 +27,6 @@ 
 
 extern void __libc_init_first (int argc, char **argv, char **envp);
 
-extern int __libc_multiple_libcs;
-
 #include <tls.h>
 #ifndef SHARED
 # include <dl-osinfo.h>
diff --git a/elf/dl-open.c b/elf/dl-open.c
index 2d8948aab1..c539f10cf3 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -33,12 +33,11 @@ 
 #include <tls.h>
 #include <stap-probe.h>
 #include <atomic.h>
+#include <libc-internal.h>
 
 #include <dl-dst.h>
 
 
-extern int __libc_multiple_libcs;	/* Defined in init-first.c.  */
-
 /* We must be careful not to leave us in an inconsistent state.  Thus we
    catch any error and re-raise it after cleaning up.  */
 
diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c
index 4053ff3c07..c4ff8b2937 100644
--- a/elf/dl-sysdep.c
+++ b/elf/dl-sysdep.c
@@ -41,7 +41,7 @@ 
 #include <dl-machine.h>
 #include <dl-procinfo.h>
 #include <dl-osinfo.h>
-#include <hp-timing.h>
+#include <libc-internal.h>
 #include <tls.h>
 
 #include <dl-tunables.h>
diff --git a/include/libc-internal.h b/include/libc-internal.h
index cd2f2622ed..c501c95eb5 100644
--- a/include/libc-internal.h
+++ b/include/libc-internal.h
@@ -53,4 +53,6 @@  extern void __init_misc (int, char **, char **);
 extern __typeof (__profile_frequency) __profile_frequency attribute_hidden;
 # endif
 
+extern int __libc_multiple_libcs attribute_hidden;
+
 #endif /* _LIBC_INTERNAL  */
diff --git a/misc/sbrk.c b/misc/sbrk.c
index 965c0ef879..158399d2ed 100644
--- a/misc/sbrk.c
+++ b/misc/sbrk.c
@@ -18,14 +18,12 @@ 
 #include <errno.h>
 #include <stdint.h>
 #include <unistd.h>
+#include <libc-internal.h>
 
 /* Defined in brk.c.  */
 extern void *__curbrk;
 extern int __brk (void *addr);
 
-/* Defined in init-first.c.  */
-extern int __libc_multiple_libcs attribute_hidden;
-
 /* Extend the process's data space by INCREMENT.
    If INCREMENT is negative, shrink data space by - INCREMENT.
    Return start of new space allocated, or -1 for errors.  */
-- 
2.13.5