Deprecate inclusion of <sys/sysmacros.h> by <sys/types.h>

The macros defined by <sys/sysmacros.h> are not part of POSIX nor XSI, and
their names frequently collide with user code; see for instance glibc bug
19239 and Red Hat bug 130601.  <stdlib.h> includes <sys/types.h> under
_GNU_SOURCE, and C++ code presently cannot avoid being compiled under
_GNU_SOURCE, exacerbating the problem.

	* NEWS: Inclusion of <sys/sysmacros.h> by <sys/types.h> is deprecated.
	* misc/sys/sysmacros.h: If __SYSMACROS_DEPRECATED_INCLUSION is defined,
	define major, minor, and makedev to issue deprecation warnings on use.
	If __SYSMACROS_DEPRECATED_INCLUSION is *not* defined, suppress
	previously-activated deprecation warnings for these macros and prevent
	subsequent inclusions of this header from having any effect.
	* posix/sys/types.h: Define __SYSMACROS_DEPRECATED_INCLUSION before
	including <sys/sysmacros.h>, and undefine it again afterward.

1 files changed, 59 insertions, 3 deletions

diff --git a/misc/sys/sysmacros.h b/misc/sys/sysmacros.h
index dc2eb837a1..086e9af5aa 100644
--- a/misc/sys/sysmacros.h
+++ b/misc/sys/sysmacros.h
@@ -16,6 +16,23 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef _SYS_SYSMACROS_H_OUTER
+
+#ifndef __SYSMACROS_DEPRECATED_INCLUSION
+# define _SYS_SYSMACROS_H_OUTER 1
+#endif
+
+/* If <sys/sysmacros.h> is included after <sys/types.h>, these macros
+   will already be defined, and we need to redefine them without the
+   deprecation warnings.  (If they are included in the opposite order,
+   the outer #ifndef will suppress this entire file and the macros
+   will be usable without warnings.)  */
+#undef major
+#undef minor
+#undef makedev
+
+/* This is the macro that must be defined to satisfy the misuse check
+   in bits/sysmacros.h. */
 #ifndef _SYS_SYSMACROS_H
 #define _SYS_SYSMACROS_H 1
 
@@ -23,32 +40,65 @@
 #include <bits/types.h>
 #include <bits/sysmacros.h>
 
+/* The extra "\n " moves gcc's [-Wdeprecated-declarations] annotation
+   onto the next line.  */
+#define __SYSMACROS_DEPRECATION_MSG(symbol)				     \
+  "\n  In the GNU C Library, `" #symbol "' is defined by <sys/sysmacros.h>." \
+  "\n  For historical compatibility, it is currently defined by"	     \
+  "\n  <sys/types.h> as well, but we plan to remove this soon."		     \
+  "\n  To use `" #symbol "', include <sys/sysmacros.h> directly."	     \
+  "\n  If you did not intend to use a system-defined macro `" #symbol "',"   \
+  "\n  you should #undef it after including <sys/types.h>."		     \
+  "\n "
+
 #define __SYSMACROS_DECL_TEMPL(rtype, name, proto)			     \
   extern rtype gnu_dev_##name proto __THROW __attribute_const__;
 
+#define __SYSMACROS_FST_DECL_TEMPL(rtype, name, proto)			     \
+  extern rtype __REDIRECT_NTH (__##name##_from_sys_types, proto,	     \
+			       gnu_dev_##name)				     \
+       __attribute_const__						     \
+       __attribute_deprecated_msg__ (__SYSMACROS_DEPRECATION_MSG (name));
+
 #define __SYSMACROS_IMPL_TEMPL(rtype, name, proto)			     \
   __extension__ __extern_inline __attribute_const__ rtype		     \
   __NTH (gnu_dev_##name proto)
 
+#define __SYSMACROS_FST_IMPL_TEMPL(rtype, name, proto)			     \
+  __extension__ __extern_inline __attribute_const__ rtype		     \
+  __NTH (__##name##_from_sys_types proto)
+
 __BEGIN_DECLS
 
 __SYSMACROS_DECLARE_MAJOR (__SYSMACROS_DECL_TEMPL)
 __SYSMACROS_DECLARE_MINOR (__SYSMACROS_DECL_TEMPL)
 __SYSMACROS_DECLARE_MAKEDEV (__SYSMACROS_DECL_TEMPL)
 
+__SYSMACROS_DECLARE_MAJOR (__SYSMACROS_FST_DECL_TEMPL)
+__SYSMACROS_DECLARE_MINOR (__SYSMACROS_FST_DECL_TEMPL)
+__SYSMACROS_DECLARE_MAKEDEV (__SYSMACROS_FST_DECL_TEMPL)
+
 #ifdef __USE_EXTERN_INLINES
 
 __SYSMACROS_DEFINE_MAJOR (__SYSMACROS_IMPL_TEMPL)
 __SYSMACROS_DEFINE_MINOR (__SYSMACROS_IMPL_TEMPL)
 __SYSMACROS_DEFINE_MAKEDEV (__SYSMACROS_IMPL_TEMPL)
 
+__SYSMACROS_DEFINE_MAJOR (__SYSMACROS_FST_IMPL_TEMPL)
+__SYSMACROS_DEFINE_MINOR (__SYSMACROS_FST_IMPL_TEMPL)
+__SYSMACROS_DEFINE_MAKEDEV (__SYSMACROS_FST_IMPL_TEMPL)
+
 #endif
 
 __END_DECLS
 
+#endif /* _SYS_SYSMACROS_H */
+
 #ifndef __SYSMACROS_NEED_IMPLEMENTATION
 # undef __SYSMACROS_DECL_TEMPL
+# undef __SYSMACROS_FST_DECL_TEMPL
 # undef __SYSMACROS_IMPL_TEMPL
+# undef __SYSMACROS_FST_IMPL_TEMPL
 # undef __SYSMACROS_DECLARE_MAJOR
 # undef __SYSMACROS_DECLARE_MINOR
 # undef __SYSMACROS_DECLARE_MAKEDEV
@@ -57,8 +107,14 @@ __END_DECLS
 # undef __SYSMACROS_DEFINE_MAKEDEV
 #endif
 
-#define major(dev) gnu_dev_major (dev)
-#define minor(dev) gnu_dev_minor (dev)
-#define makedev(maj, min) gnu_dev_makedev (maj, min)
+#ifdef __SYSMACROS_DEPRECATED_INCLUSION
+# define major(dev) __major_from_sys_types (dev)
+# define minor(dev) __minor_from_sys_types (dev)
+# define makedev(maj, min) __makedev_from_sys_types (maj, min)
+#else
+# define major(dev) gnu_dev_major (dev)
+# define minor(dev) gnu_dev_minor (dev)
+# define makedev(maj, min) gnu_dev_makedev (maj, min)
+#endif
 
 #endif /* sys/sysmacros.h */