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(1, 0) |
34 | #define __LIBBPF_MARK_DEPRECATED_1_0(X) X |
35 | #else |
36 | #define __LIBBPF_MARK_DEPRECATED_1_0(X) |
37 | #endif |
38 | |
39 | /* This set of internal macros allows to do "function overloading" based on |
40 | * number of arguments provided by used in backwards-compatible way during the |
41 | * transition to libbpf 1.0 |
42 | * It's ugly but necessary evil that will be cleaned up when we get to 1.0. |
43 | * See bpf_prog_load() overload for example. |
44 | */ |
45 | #define ___libbpf_cat(A, B) A ## B |
46 | #define ___libbpf_select(NAME, NUM) ___libbpf_cat(NAME, NUM) |
47 | #define ___libbpf_nth(_1, _2, _3, _4, _5, _6, N, ...) N |
48 | #define ___libbpf_cnt(...) ___libbpf_nth(__VA_ARGS__, 6, 5, 4, 3, 2, 1) |
49 | #define ___libbpf_overload(NAME, ...) ___libbpf_select(NAME, ___libbpf_cnt(__VA_ARGS__))(__VA_ARGS__) |
50 | |
51 | /* Helper macro to declare and initialize libbpf options struct |
52 | * |
53 | * This dance with uninitialized declaration, followed by memset to zero, |
54 | * followed by assignment using compound literal syntax is done to preserve |
55 | * ability to use a nice struct field initialization syntax and **hopefully** |
56 | * have all the padding bytes initialized to zero. It's not guaranteed though, |
57 | * when copying literal, that compiler won't copy garbage in literal's padding |
58 | * bytes, but that's the best way I've found and it seems to work in practice. |
59 | * |
60 | * Macro declares opts struct of given type and name, zero-initializes, |
61 | * including any extra padding, it with memset() and then assigns initial |
62 | * values provided by users in struct initializer-syntax as varargs. |
63 | */ |
64 | #define LIBBPF_OPTS(TYPE, NAME, ...) \ |
65 | struct TYPE NAME = ({ \ |
66 | memset(&NAME, 0, sizeof(struct TYPE)); \ |
67 | (struct TYPE) { \ |
68 | .sz = sizeof(struct TYPE), \ |
69 | __VA_ARGS__ \ |
70 | }; \ |
71 | }) |
72 | |
73 | /* Helper macro to clear and optionally reinitialize libbpf options struct |
74 | * |
75 | * Small helper macro to reset all fields and to reinitialize the common |
76 | * structure size member. Values provided by users in struct initializer- |
77 | * syntax as varargs can be provided as well to reinitialize options struct |
78 | * specific members. |
79 | */ |
80 | #define LIBBPF_OPTS_RESET(NAME, ...) \ |
81 | do { \ |
82 | typeof(NAME) ___##NAME = ({ \ |
83 | memset(&___##NAME, 0, sizeof(NAME)); \ |
84 | (typeof(NAME)) { \ |
85 | .sz = sizeof(NAME), \ |
86 | __VA_ARGS__ \ |
87 | }; \ |
88 | }); \ |
89 | memcpy(&NAME, &___##NAME, sizeof(NAME)); \ |
90 | } while (0) |
91 | |
92 | #endif /* __LIBBPF_LIBBPF_COMMON_H */ |
93 | |