acrn-kernel/tools/lib/bpf/libbpf_common.h

43 lines
1.4 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>
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))
/* 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 DECLARE_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 */