xattr: guard against simultaneous glibc header inclusion

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.) Signed-off-by: Serge Hallyn <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Allan McRae <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
rakesh-gopal · Apr 3, 2014 · ea1a821 · ea1a821
1 parent e9107f8
commit ea1a821
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diff --git 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
@@ -7,11 +7,18 @@
   Copyright (c) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.
   Copyright (c) 2004 Red Hat, Inc., James Morris <[email protected]>
 */
+
+#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."