linux/tools/lib/bpf/libbpf_common.h
Andrii Nakryiko a11113a2dc libbpf: cleanup LIBBPF_DEPRECATED_SINCE supporting macros for v0.x
Keep the LIBBPF_DEPRECATED_SINCE macro "framework" for future
deprecations, but clean up 0.x related helper macros.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220627211527.2245459-11-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28 13:13:33 -07:00

74 lines
2.7 KiB
C

/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/*
* Common user-facing libbpf helpers.
*
* Copyright (c) 2019 Facebook
*/
#ifndef __LIBBPF_LIBBPF_COMMON_H
#define __LIBBPF_LIBBPF_COMMON_H
#include <string.h>
#include "libbpf_version.h"
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))
/* Mark a symbol as deprecated when libbpf version is >= {major}.{minor} */
#define LIBBPF_DEPRECATED_SINCE(major, minor, msg) \
__LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor \
(LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg))
#define __LIBBPF_CURRENT_VERSION_GEQ(major, minor) \
(LIBBPF_MAJOR_VERSION > (major) || \
(LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor)))
/* Add checks for other versions below when planning deprecation of API symbols
* with the LIBBPF_DEPRECATED_SINCE macro.
*/
#if __LIBBPF_CURRENT_VERSION_GEQ(1, 0)
#define __LIBBPF_MARK_DEPRECATED_1_0(X) X
#else
#define __LIBBPF_MARK_DEPRECATED_1_0(X)
#endif
/* This set of internal macros allows to do "function overloading" based on
* number of arguments provided by used in backwards-compatible way during the
* transition to libbpf 1.0
* It's ugly but necessary evil that will be cleaned up when we get to 1.0.
* See bpf_prog_load() overload for example.
*/
#define ___libbpf_cat(A, B) A ## B
#define ___libbpf_select(NAME, NUM) ___libbpf_cat(NAME, NUM)
#define ___libbpf_nth(_1, _2, _3, _4, _5, _6, N, ...) N
#define ___libbpf_cnt(...) ___libbpf_nth(__VA_ARGS__, 6, 5, 4, 3, 2, 1)
#define ___libbpf_overload(NAME, ...) ___libbpf_select(NAME, ___libbpf_cnt(__VA_ARGS__))(__VA_ARGS__)
/* Helper macro to declare and initialize libbpf options struct
*
* This dance with uninitialized declaration, followed by memset to zero,
* followed by assignment using compound literal syntax is done to preserve
* ability to use a nice struct field initialization syntax and **hopefully**
* have all the padding bytes initialized to zero. It's not guaranteed though,
* when copying literal, that compiler won't copy garbage in literal's padding
* bytes, but that's the best way I've found and it seems to work in practice.
*
* Macro declares opts struct of given type and name, zero-initializes,
* including any extra padding, it with memset() and then assigns initial
* values provided by users in struct initializer-syntax as varargs.
*/
#define LIBBPF_OPTS(TYPE, NAME, ...) \
struct TYPE NAME = ({ \
memset(&NAME, 0, sizeof(struct TYPE)); \
(struct TYPE) { \
.sz = sizeof(struct TYPE), \
__VA_ARGS__ \
}; \
})
#endif /* __LIBBPF_LIBBPF_COMMON_H */