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1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2
3/*
4 * Common user-facing libbpf helpers.
5 *
6 * Copyright (c) 2019 Facebook
7 */
8
9#ifndef __LIBBPF_LIBBPF_COMMON_H
10#define __LIBBPF_LIBBPF_COMMON_H
11
12#include <string.h>
13#include "libbpf_version.h"
14
15#ifndef LIBBPF_API
16#define LIBBPF_API __attribute__((visibility("default")))
17#endif
18
19#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))
20
21/* Mark a symbol as deprecated when libbpf version is >= {major}.{minor} */
22#define LIBBPF_DEPRECATED_SINCE(major, minor, msg) \
23 __LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor \
24 (LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg))
25
26#define __LIBBPF_CURRENT_VERSION_GEQ(major, minor) \
27 (LIBBPF_MAJOR_VERSION > (major) || \
28 (LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor)))
29
30/* Add checks for other versions below when planning deprecation of API symbols
31 * with the LIBBPF_DEPRECATED_SINCE macro.
32 */
33#if __LIBBPF_CURRENT_VERSION_GEQ(0, 6)
34#define __LIBBPF_MARK_DEPRECATED_0_6(X) X
35#else
36#define __LIBBPF_MARK_DEPRECATED_0_6(X)
37#endif
38#if __LIBBPF_CURRENT_VERSION_GEQ(0, 7)
39#define __LIBBPF_MARK_DEPRECATED_0_7(X) X
40#else
41#define __LIBBPF_MARK_DEPRECATED_0_7(X)
42#endif
43#if __LIBBPF_CURRENT_VERSION_GEQ(0, 8)
44#define __LIBBPF_MARK_DEPRECATED_0_8(X) X
45#else
46#define __LIBBPF_MARK_DEPRECATED_0_8(X)
47#endif
48
49/* This set of internal macros allows to do "function overloading" based on
50 * number of arguments provided by used in backwards-compatible way during the
51 * transition to libbpf 1.0
52 * It's ugly but necessary evil that will be cleaned up when we get to 1.0.
53 * See bpf_prog_load() overload for example.
54 */
55#define ___libbpf_cat(A, B) A ## B
56#define ___libbpf_select(NAME, NUM) ___libbpf_cat(NAME, NUM)
57#define ___libbpf_nth(_1, _2, _3, _4, _5, _6, N, ...) N
58#define ___libbpf_cnt(...) ___libbpf_nth(__VA_ARGS__, 6, 5, 4, 3, 2, 1)
59#define ___libbpf_overload(NAME, ...) ___libbpf_select(NAME, ___libbpf_cnt(__VA_ARGS__))(__VA_ARGS__)
60
61/* Helper macro to declare and initialize libbpf options struct
62 *
63 * This dance with uninitialized declaration, followed by memset to zero,
64 * followed by assignment using compound literal syntax is done to preserve
65 * ability to use a nice struct field initialization syntax and **hopefully**
66 * have all the padding bytes initialized to zero. It's not guaranteed though,
67 * when copying literal, that compiler won't copy garbage in literal's padding
68 * bytes, but that's the best way I've found and it seems to work in practice.
69 *
70 * Macro declares opts struct of given type and name, zero-initializes,
71 * including any extra padding, it with memset() and then assigns initial
72 * values provided by users in struct initializer-syntax as varargs.
73 */
74#define LIBBPF_OPTS(TYPE, NAME, ...) \
75 struct TYPE NAME = ({ \
76 memset(&NAME, 0, sizeof(struct TYPE)); \
77 (struct TYPE) { \
78 .sz = sizeof(struct TYPE), \
79 __VA_ARGS__ \
80 }; \
81 })
82
83#endif /* __LIBBPF_LIBBPF_COMMON_H */