linux/tools/testing/selftests/bpf/progs/test_core_reloc_mods.c

// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook

#include <linux/bpf.h>
#include <stdint.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>

char _license[] SEC("license") = "GPL";

struct {
	char in[256];
	char out[256];
} data = {};

struct core_reloc_mods_output {
	int a, b, c, d, e, f, g, h;
};

typedef const int int_t;
typedef const char *char_ptr_t;
typedef const int arr_t[7];

struct core_reloc_mods_substruct {
	int x;
	int y;
};

typedef struct {
	int x;
	int y;
} core_reloc_mods_substruct_t;

struct core_reloc_mods {
	int a;
	int_t b;
	char *c;
	char_ptr_t d;
	int e[3];
	arr_t f;
	struct core_reloc_mods_substruct g;
	core_reloc_mods_substruct_t h;
};

#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define CORE_READ(dst, src) bpf_core_read(dst, sizeof(*(dst)), src)
#else
#define CORE_READ(dst, src) ({ \
	int __sz = sizeof(*(dst)) < sizeof(*(src)) ? sizeof(*(dst)) : \
						     sizeof(*(src)); \
	bpf_core_read((char *)(dst) + sizeof(*(dst)) - __sz, __sz, \
		      (const char *)(src) + sizeof(*(src)) - __sz); \
})
#endif

SEC("raw_tracepoint/sys_enter")
int test_core_mods(void *ctx)
{
	struct core_reloc_mods *in = (void *)&data.in;
	struct core_reloc_mods_output *out = (void *)&data.out;

	if (CORE_READ(&out->a, &in->a) ||
	    CORE_READ(&out->b, &in->b) ||
	    CORE_READ(&out->c, &in->c) ||
	    CORE_READ(&out->d, &in->d) ||
	    CORE_READ(&out->e, &in->e[2]) ||
	    CORE_READ(&out->f, &in->f[1]) ||
	    CORE_READ(&out->g, &in->g.x) ||
	    CORE_READ(&out->h, &in->h.y))
		return 1;

	return 0;
}