| 1 |
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| 2 |
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| 3 | |
| 4 | * Common user-facing libbpf helpers.
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| 5 | *
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| 6 | * Copyright (c) 2019 Facebook
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| 7 |
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| 8 |
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| 9 | #ifndef __LIBBPF_LIBBPF_COMMON_H
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| 10 | #define __LIBBPF_LIBBPF_COMMON_H
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| 11 |
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| 12 | #include <string.h>
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| 13 | #include "libbpf_version.h"
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| 14 |
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| 15 | #ifndef LIBBPF_API
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| 16 | #define LIBBPF_API __attribute__((visibility("default")))
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| 17 | #endif
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| 18 |
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| 19 | #define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))
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| 20 |
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| 21 |
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| 22 | #define LIBBPF_DEPRECATED_SINCE(major, minor, msg) \
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| 23 | __LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor \
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| 24 | (LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg))
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| 25 |
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| 26 | #define __LIBBPF_CURRENT_VERSION_GEQ(major, minor) \
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| 27 | (LIBBPF_MAJOR_VERSION > (major) || \
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| 28 | (LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor)))
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| 29 |
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| 30 | |
| 31 | * with the LIBBPF_DEPRECATED_SINCE macro.
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| 32 |
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| 33 | #if __LIBBPF_CURRENT_VERSION_GEQ(1, 0)
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| 34 | #define __LIBBPF_MARK_DEPRECATED_1_0(X) X
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| 35 | #else
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| 36 | #define __LIBBPF_MARK_DEPRECATED_1_0(X)
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| 37 | #endif
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| 38 |
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| 39 | |
| 40 | * number of arguments provided by used in backwards-compatible way during the
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| 41 | * transition to libbpf 1.0
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| 42 | * It's ugly but necessary evil that will be cleaned up when we get to 1.0.
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| 43 | * See bpf_prog_load() overload for example.
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| 44 |
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| 45 | #define ___libbpf_cat(A, B) A ## B
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| 46 | #define ___libbpf_select(NAME, NUM) ___libbpf_cat(NAME, NUM)
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| 47 | #define ___libbpf_nth(_1, _2, _3, _4, _5, _6, N, ...) N
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| 48 | #define ___libbpf_cnt(...) ___libbpf_nth(__VA_ARGS__, 6, 5, 4, 3, 2, 1)
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| 49 | #define ___libbpf_overload(NAME, ...) ___libbpf_select(NAME, ___libbpf_cnt(__VA_ARGS__))(__VA_ARGS__)
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| 50 |
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| 51 | |
| 52 | *
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| 53 | * This dance with uninitialized declaration, followed by memset to zero,
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| 54 | * followed by assignment using compound literal syntax is done to preserve
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| 55 | * ability to use a nice struct field initialization syntax and **hopefully**
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| 56 | * have all the padding bytes initialized to zero. It's not guaranteed though,
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| 57 | * when copying literal, that compiler won't copy garbage in literal's padding
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| 58 | * bytes, but that's the best way I've found and it seems to work in practice.
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| 59 | *
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| 60 | * Macro declares opts struct of given type and name, zero-initializes,
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| 61 | * including any extra padding, it with memset() and then assigns initial
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| 62 | * values provided by users in struct initializer-syntax as varargs.
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| 63 |
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| 64 | #define LIBBPF_OPTS(TYPE, NAME, ...) \
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| 65 | struct TYPE NAME = ({ \
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| 66 | memset(&NAME, 0, sizeof(struct TYPE)); \
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| 67 | (struct TYPE) { \
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| 68 | .sz = sizeof(struct TYPE), \
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| 69 | __VA_ARGS__ \
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| 70 | }; \
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| 71 | })
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| 72 |
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| 73 | |
| 74 | *
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| 75 | * Small helper macro to reset all fields and to reinitialize the common
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| 76 | * structure size member. Values provided by users in struct initializer-
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| 77 | * syntax as varargs can be provided as well to reinitialize options struct
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| 78 | * specific members.
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| 79 |
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| 80 | #define LIBBPF_OPTS_RESET(NAME, ...) \
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| 81 | do { \
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| 82 | typeof(NAME) ___##NAME = ({ \
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| 83 | memset(&___##NAME, 0, sizeof(NAME)); \
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| 84 | (typeof(NAME)) { \
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| 85 | .sz = sizeof(NAME), \
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| 86 | __VA_ARGS__ \
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| 87 | }; \
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| 88 | }); \
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| 89 | memcpy(&NAME, &___##NAME, sizeof(NAME)); \
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| 90 | } while (0)
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| 91 |
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| 92 | #endif
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