tools/headers: Pull in stddef.h to uapi to fix BPF selftests build in CI

With recent sync of linux/in.h tools/include headers are now relying on
__DECLARE_FLEX_ARRAY macro, which isn't itself defined inside
tools/include headers anywhere and is instead assumed to be present in
system-wide UAPI header. This breaks isolated environments that don't
have kernel UAPI headers installed system-wide, like BPF CI ([0]).

To fix this, bring in include/uapi/linux/stddef.h into tools/include.
We can't just copy/paste it, though, it has to be processed with
scripts/headers_install.sh, which has a dependency on scripts/unifdef.
So the full command to (re-)generate stddef.h for inclusion into
tools/include directory is:

  $ make scripts_unifdef && \
    cp $KBUILD_OUTPUT/scripts/unifdef scripts/ && \
    scripts/headers_install.sh include/uapi/linux/stddef.h tools/include/uapi/linux/stddef.h

This assumes KBUILD_OUTPUT envvar is set and used for out-of-tree builds.

  [0] https://github.com/kernel-patches/bpf/actions/runs/3379432493/jobs/5610982609

Fixes: 036b8f5b89 ("tools headers uapi: Update linux/in.h copy")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/bpf/20221102182517.2675301-2-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2022-11-02 11:25:17 -07:00 committed by Daniel Borkmann
parent aec1dc972d
commit a778f5d46b
2 changed files with 48 additions and 0 deletions

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@ -20,6 +20,7 @@
#define _UAPI_LINUX_IN_H
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/libc-compat.h>
#include <linux/socket.h>

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@ -0,0 +1,47 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _LINUX_STDDEF_H
#define _LINUX_STDDEF_H
#ifndef __always_inline
#define __always_inline __inline__
#endif
/**
* __struct_group() - Create a mirrored named and anonyomous struct
*
* @TAG: The tag name for the named sub-struct (usually empty)
* @NAME: The identifier name of the mirrored sub-struct
* @ATTRS: Any struct attributes (usually empty)
* @MEMBERS: The member declarations for the mirrored structs
*
* Used to create an anonymous union of two structs with identical layout
* and size: one anonymous and one named. The former's members can be used
* normally without sub-struct naming, and the latter can be used to
* reason about the start, end, and size of the group of struct members.
* The named struct can also be explicitly tagged for layer reuse, as well
* as both having struct attributes appended.
*/
#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
union { \
struct { MEMBERS } ATTRS; \
struct TAG { MEMBERS } ATTRS NAME; \
}
/**
* __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union
*
* @TYPE: The type of each flexible array element
* @NAME: The name of the flexible array member
*
* In order to have a flexible array member in a union or alone in a
* struct, it needs to be wrapped in an anonymous struct with at least 1
* named member, but that member can be empty.
*/
#define __DECLARE_FLEX_ARRAY(TYPE, NAME) \
struct { \
struct { } __empty_ ## NAME; \
TYPE NAME[]; \
}
#endif