warn about use of uninstalled kernel headers

User applications frequently hit problems when they try to use the kernel headers directly, rather than the exported headers. This adds an explicit warning for this case, and points to a URL holding an explanation of why this is wrong and what to do about it. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

warn about use of uninstalled kernel headers
User applications frequently hit problems when they try to use the kernel headers directly, rather than the exported headers. This adds an explicit warning for this case, and points to a URL holding an explanation of why this is wrong and what to do about it. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Arnd Bergmann · Sam Ravnborg
1 parent 17c5ca9883
Showing 2 changed files with 7 additions and 1 deletions Side-by-side Diff
include/linux/kernel.h
scripts/headers_install.pl
@@ -659,6 +659,12 @@
  
 #endif /* __KERNEL__ */
  
+#ifndef __EXPORTED_HEADERS__
+#ifndef __KERNEL__
+#warning Attempt to use kernel headers from user space, see http://kernelnewbies.org/KernelHeaders
+#endif /* __KERNEL__ */
+#endif /* __EXPORTED_HEADERS__ */
+
 #define SI_LOAD_SHIFT	16
 struct sysinfo {
 	long uptime;			/* Seconds since boot */
@@ -20,7 +20,7 @@
  
 my ($readdir, $installdir, $arch, @files) = @ARGV;
  
-my $unifdef = "scripts/unifdef -U__KERNEL__";
+my $unifdef = "scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__";
  
 foreach my $file (@files) {
 	local *INFILE;
...	...	@@ -659,6 +659,12 @@
659	659
660	660	#endif /* __KERNEL__ */
661	661
	662	+#ifndef __EXPORTED_HEADERS__
	663	+#ifndef __KERNEL__
	664	+#warning Attempt to use kernel headers from user space, see http://kernelnewbies.org/KernelHeaders
	665	+#endif /* __KERNEL__ */
	666	+#endif /* __EXPORTED_HEADERS__ */
	667	+
662	668	#define SI_LOAD_SHIFT 16
663	669	struct sysinfo {
664	670	long uptime; /* Seconds since boot */
...	...	@@ -20,7 +20,7 @@
20	20
21	21	my ($readdir, $installdir, $arch, @files) = @ARGV;
22	22
23		-my $unifdef = "scripts/unifdef -U__KERNEL__";
	23	+my $unifdef = "scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__";
24	24
25	25	foreach my $file (@files) {
26	26	local *INFILE;