From ca7dc2791b507f842d73e46b1a0453b36b69ffc2 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Sat, 29 Feb 2020 15:11:09 -0800 Subject: [PATCH] bpftool: Add header guards to generated vmlinux.h Add canonical #ifndef/#define/#endif guard for generated vmlinux.h header with __VMLINUX_H__ symbol. __VMLINUX_H__ is also going to play double role of identifying whether vmlinux.h is being used, versus, say, BCC or non-CO-RE libbpf modes with dependency on kernel headers. This will make it possible to write helper macro/functions, agnostic to exact BPF program set up. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200229231112.1240137-2-andriin@fb.com --- tools/bpf/bpftool/btf.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index b3745ed711ba..bcaf55b59498 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -389,6 +389,9 @@ static int dump_btf_c(const struct btf *btf, if (IS_ERR(d)) return PTR_ERR(d); + printf("#ifndef __VMLINUX_H__\n"); + printf("#define __VMLINUX_H__\n"); + printf("\n"); printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n"); printf("#endif\n\n"); @@ -412,6 +415,8 @@ static int dump_btf_c(const struct btf *btf, printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); printf("#pragma clang attribute pop\n"); printf("#endif\n"); + printf("\n"); + printf("#endif /* __VMLINUX_H__ */\n"); done: btf_dump__free(d); -- 2.30.2