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
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Fixes: 036b8f5b8970 ("tools headers uapi: Update linux/in.h copy")
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
tools/include/uapi/linux/in.h | 1 +
tools/include/uapi/linux/stddef.h | 47 +++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+)
create mode 100644 tools/include/uapi/linux/stddef.h
diff --git a/tools/include/uapi/linux/in.h b/tools/include/uapi/linux/in.h
index f243ce665f74..07a4cb149305 100644
--- a/tools/include/uapi/linux/in.h
+++ b/tools/include/uapi/linux/in.h
@@ -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>
diff --git a/tools/include/uapi/linux/stddef.h b/tools/include/uapi/linux/stddef.h
new file mode 100644
index 000000000000..bb6ea517efb5
--- /dev/null
+++ b/tools/include/uapi/linux/stddef.h
@@ -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
--
2.30.2
