From: Masahiro Yamada <masahiroy@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org, linux-arch@vger.kernel.org,
Masahiro Yamada <masahiroy@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH 2/8] kbuild: prevent exported headers from including <stdlib.h>, <stdbool.h>
Date: Mon, 4 Apr 2022 15:19:42 +0900 [thread overview]
Message-ID: <20220404061948.2111820-3-masahiroy@kernel.org> (raw)
In-Reply-To: <20220404061948.2111820-1-masahiroy@kernel.org>
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>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
usr/dummy-include/stdbool.h | 7 +++++++
usr/dummy-include/stdlib.h | 7 +++++++
usr/include/Makefile | 2 +-
3 files changed, 15 insertions(+), 1 deletion(-)
create mode 100644 usr/dummy-include/stdbool.h
create mode 100644 usr/dummy-include/stdlib.h
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.
#
--
2.32.0
next prev parent reply other threads:[~2022-04-04 6:21 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-04 6:19 [PATCH 0/8] UAPI: make more exported headers self-contained, and put them into test coverage Masahiro Yamada
2022-04-04 6:19 ` [PATCH 1/8] agpgart.h: do not include <stdlib.h> from exported header Masahiro Yamada
2022-04-04 7:40 ` Christoph Hellwig
2022-04-04 17:27 ` Nick Desaulniers
2022-04-04 6:19 ` Masahiro Yamada [this message]
2022-04-04 7:41 ` [PATCH 2/8] kbuild: prevent exported headers from including <stdlib.h>, <stdbool.h> Christoph Hellwig
2022-04-04 8:01 ` Arnd Bergmann
2022-04-04 8:03 ` Masahiro Yamada
2022-04-04 17:34 ` Nick Desaulniers
2022-04-05 1:12 ` Masahiro Yamada
2022-04-04 6:19 ` [PATCH 3/8] riscv: add linux/bpf_perf_event.h to UAPI compile-test coverage Masahiro Yamada
2022-04-04 7:41 ` Christoph Hellwig
2022-04-04 6:19 ` [PATCH 4/8] mips: add asm/stat.h " Masahiro Yamada
2022-04-04 7:42 ` Christoph Hellwig
2022-04-04 6:19 ` [PATCH 5/8] powerpc: " Masahiro Yamada
2022-04-04 7:42 ` Christoph Hellwig
2022-04-04 6:19 ` [PATCH 6/8] sparc: " Masahiro Yamada
2022-04-04 7:43 ` Christoph Hellwig
2022-04-04 6:19 ` [PATCH 7/8] posix_types.h: add __kernel_uintptr_t to UAPI posix_types.h Masahiro Yamada
2022-04-04 11:30 ` kernel test robot
2022-04-04 11:51 ` Masahiro Yamada
2022-04-04 12:02 ` Masahiro Yamada
2022-04-04 11:51 ` kernel test robot
2022-04-04 13:04 ` kernel test robot
2022-04-04 6:19 ` [PATCH 8/8] virtio_ring.h: do not include <stdint.h> from exported header Masahiro Yamada
2022-04-04 7:44 ` Christoph Hellwig
2022-04-04 7:58 ` Masahiro Yamada
2022-04-04 8:04 ` Arnd Bergmann
2022-04-05 5:35 ` Christoph Hellwig
2022-04-05 6:29 ` Arnd Bergmann
2022-04-05 7:01 ` Christoph Hellwig
2022-04-05 11:55 ` Michael S. Tsirkin
2022-04-05 11:57 ` Michael S. Tsirkin
2022-04-05 11:59 ` Michael S. Tsirkin
2022-04-05 11:57 ` Michael S. Tsirkin
2022-04-04 7:34 ` [PATCH 0/8] UAPI: make more exported headers self-contained, and put them into test coverage Arnd Bergmann
2022-05-13 8:43 ` Masahiro Yamada
2022-05-13 9:01 ` Arnd Bergmann
2022-05-13 9:13 ` Masahiro Yamada
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