Commit 544402d4 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov

libbpf: Extract common user-facing helpers

LIBBPF_API and DECLARE_LIBBPF_OPTS are needed in many public libbpf API
headers. Extract them into libbpf_common.h to avoid unnecessary
interdependency between btf.h, libbpf.h, and bpf.h or code duplication.
Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-6-andriin@fb.com
parent 917f6b7b
...@@ -28,14 +28,12 @@ ...@@ -28,14 +28,12 @@
#include <stddef.h> #include <stddef.h>
#include <stdint.h> #include <stdint.h>
#include "libbpf_common.h"
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
struct bpf_create_map_attr { struct bpf_create_map_attr {
const char *name; const char *name;
enum bpf_map_type map_type; enum bpf_map_type map_type;
......
...@@ -8,14 +8,12 @@ ...@@ -8,14 +8,12 @@
#include <linux/btf.h> #include <linux/btf.h>
#include <linux/types.h> #include <linux/types.h>
#include "libbpf_common.h"
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
#define BTF_ELF_SEC ".BTF" #define BTF_ELF_SEC ".BTF"
#define BTF_EXT_ELF_SEC ".BTF.ext" #define BTF_EXT_ELF_SEC ".BTF.ext"
#define MAPS_ELF_SEC ".maps" #define MAPS_ELF_SEC ".maps"
......
...@@ -17,14 +17,12 @@ ...@@ -17,14 +17,12 @@
#include <sys/types.h> // for size_t #include <sys/types.h> // for size_t
#include <linux/bpf.h> #include <linux/bpf.h>
#include "libbpf_common.h"
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
enum libbpf_errno { enum libbpf_errno {
__LIBBPF_ERRNO__START = 4000, __LIBBPF_ERRNO__START = 4000,
...@@ -67,28 +65,6 @@ struct bpf_object_open_attr { ...@@ -67,28 +65,6 @@ struct bpf_object_open_attr {
enum bpf_prog_type prog_type; enum bpf_prog_type prog_type;
}; };
/* 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__ \
}; \
})
struct bpf_object_open_opts { struct bpf_object_open_opts {
/* size of this struct, for forward/backward compatiblity */ /* size of this struct, for forward/backward compatiblity */
size_t sz; size_t sz;
......
/* 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
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
/* 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 */
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