diff options
| author | Masahiro Yamada <masahiroy@kernel.org> | 2022-04-04 15:19:42 +0900 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2022-05-13 10:56:10 +0200 |
| commit | 02a6e4be2ff44344f58b078c18dc3ab3877fcfe5 (patch) | |
| tree | 386a0581ce2dd8e4b1d456666f9007f54c90638f /usr | |
| parent | 783eb354fb3dcd598e8e7e8a2ed88c0fb6ce5d2f (diff) | |
| download | lwn-02a6e4be2ff44344f58b078c18dc3ab3877fcfe5.tar.gz lwn-02a6e4be2ff44344f58b078c18dc3ab3877fcfe5.zip | |
kbuild: prevent exported headers from including <stdlib.h>, <stdbool.h>
Some UAPI headers included <stdlib.h>, like this:
#ifndef __KERNEL__
#include <stdlib.h>
#endif
As it turned out, they just included it for no good reason.
After some fixes, now I can compile-test UAPI headers
(CONFIG_UAPI_HEADER_TEST=y) without including <stdlib.h> from the
system header search paths.
To avoid somebody getting it back again, this commit adds the dummy
header, usr/dummy-include/stdlib.h
I added $(srctree)/usr/dummy-include to the header search paths.
Because it is searched before the system directories, if someone
tries to include <stdlib.h>, they will see the error message.
While I am here, I also replaced $(objtree)/usr/include with $(obj),
but it has no functional change.
If we can make kernel headers self-contained (that is, none of exported
kernel headers includes system headers), we will be able to add the
-nostdinc flag, but that is much far from where we stand now.
As a realistic solution, we can ban header inclusion individually by
putting a dummy header into usr/dummy-include/.
Currently, no header include <stdbool.h>. I put it as well before somebody
attempts to use it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'usr')
| -rw-r--r-- | usr/dummy-include/stdbool.h | 7 | ||||
| -rw-r--r-- | usr/dummy-include/stdlib.h | 7 | ||||
| -rw-r--r-- | usr/include/Makefile | 2 |
3 files changed, 15 insertions, 1 deletions
diff --git a/usr/dummy-include/stdbool.h b/usr/dummy-include/stdbool.h new file mode 100644 index 000000000000..54ff9e9c90ac --- /dev/null +++ b/usr/dummy-include/stdbool.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _STDBOOL_H +#define _STDBOOL_H + +#error "Please do not include <stdbool.h> from exported headers" + +#endif /* _STDBOOL_H */ diff --git a/usr/dummy-include/stdlib.h b/usr/dummy-include/stdlib.h new file mode 100644 index 000000000000..e8c21888e371 --- /dev/null +++ b/usr/dummy-include/stdlib.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _STDLIB_H +#define _STDLIB_H + +#error "Please do not include <stdlib.h> from exported headers" + +#endif /* _STDLIB_H */ diff --git a/usr/include/Makefile b/usr/include/Makefile index fa9819e022b7..7740777b49f8 100644 --- a/usr/include/Makefile +++ b/usr/include/Makefile @@ -15,7 +15,7 @@ UAPI_CFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS)) # USERCFLAGS might contain sysroot location for CC. UAPI_CFLAGS += $(USERCFLAGS) -override c_flags = $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I$(objtree)/usr/include +override c_flags = $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I $(obj) -I $(srctree)/usr/dummy-include # The following are excluded for now because they fail to build. # |