544402d4b4
LIBBPF_API and DECLARE_LIBBPF_OPTS are needed in many public libbpf API headers. Extract them into libbpf_common.h to avoid unnecessary interdependency between btf.h, libbpf.h, and bpf.h or code duplication. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014341.3442258-6-andriin@fb.com
39 lines
1.3 KiB
C
39 lines
1.3 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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/*
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* Common user-facing libbpf helpers.
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*
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* Copyright (c) 2019 Facebook
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*/
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#ifndef __LIBBPF_LIBBPF_COMMON_H
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#define __LIBBPF_LIBBPF_COMMON_H
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#ifndef LIBBPF_API
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#define LIBBPF_API __attribute__((visibility("default")))
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#endif
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/* Helper macro to declare and initialize libbpf options struct
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*
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* This dance with uninitialized declaration, followed by memset to zero,
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* followed by assignment using compound literal syntax is done to preserve
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* ability to use a nice struct field initialization syntax and **hopefully**
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* have all the padding bytes initialized to zero. It's not guaranteed though,
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* when copying literal, that compiler won't copy garbage in literal's padding
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* bytes, but that's the best way I've found and it seems to work in practice.
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*
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* Macro declares opts struct of given type and name, zero-initializes,
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* including any extra padding, it with memset() and then assigns initial
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* values provided by users in struct initializer-syntax as varargs.
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*/
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#define DECLARE_LIBBPF_OPTS(TYPE, NAME, ...) \
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struct TYPE NAME = ({ \
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memset(&NAME, 0, sizeof(struct TYPE)); \
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(struct TYPE) { \
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.sz = sizeof(struct TYPE), \
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__VA_ARGS__ \
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}; \
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})
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#endif /* __LIBBPF_LIBBPF_COMMON_H */
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