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[PATCH] xattr: guard against simultaneous glibc header inclusion (v2)
- From: Serge Hallyn <serge dot hallyn at ubuntu dot com>
- To: linux-kernel at vger dot kernel dot org
- Cc: linux-fsdevel at vger dot kernel dot org, Andrew Morton <akpm at linux-foundation dot org>, Allan McRae <allan at archlinux dot org>, libc-alpha at sourceware dot org
- Date: Fri, 21 Mar 2014 00:02:28 -0500
- Subject: [PATCH] xattr: guard against simultaneous glibc header inclusion (v2)
- Authentication-results: sourceware.org; auth=none
If the glibc xattr.h header is included after the uapi header,
compilation fails due to an enum re-using a #define from the
uapi header. Protect against this by guarding the define and
enum inclusions against each other.
(See https://lists.debian.org/debian-glibc/2014/03/msg00029.html
and https://sourceware.org/glibc/wiki/Synchronizing_Headers
for more information.)
v2: As Allan McRae points out, __UAPI_DFE_XATTR should only be
set to zero when _SYS_XATTR_H is defined.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Allan McRae <allan@archlinux.org>
Cc: libc-alpha@sourceware.org
---
include/uapi/linux/libc-compat.h | 9 +++++++++
include/uapi/linux/xattr.h | 7 +++++++
2 files changed, 16 insertions(+)
diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h
index 335e8a7..0b73ee9 100644
--- a/include/uapi/linux/libc-compat.h
+++ b/include/uapi/linux/libc-compat.h
@@ -85,6 +85,12 @@
#endif /* _NETINET_IN_H */
+/* Definitions for xattr.h */
+#if defined(_SYS_XATTR_H)
+#define __UAPI_DEF_XATTR 0
+#else
+#define __UAPI_DEF_XATTR 1
+#endif
/* If we did not see any headers from any supported C libraries,
* or we are being included in the kernel, then define everything
@@ -98,6 +104,9 @@
#define __UAPI_DEF_IPV6_MREQ 1
#define __UAPI_DEF_IPPROTO_V6 1
+/* Definitions for xattr.h */
+#define __UAPI_DEF_XATTR 1
+
#endif /* __GLIBC__ */
#endif /* _UAPI_LIBC_COMPAT_H */
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index e4629b9..a63c146 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -7,11 +7,18 @@
Copyright (c) 2001-2002 Silicon Graphics, Inc. All Rights Reserved.
Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
*/
+
+#include <linux/libc-compat.h>
+
#ifndef _UAPI_LINUX_XATTR_H
#define _UAPI_LINUX_XATTR_H
+#ifdef __UAPI_DEF_XATTR
+#define __USE_KERNEL_XATTR_DEFS
+
#define XATTR_CREATE 0x1 /* set value, fail if attr already exists */
#define XATTR_REPLACE 0x2 /* set value, fail if attr does not exist */
+#endif
/* Namespaces */
#define XATTR_OS2_PREFIX "os2."
--
1.9.1