// 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_existence_output {
        int a_exists;
        int a_value;
        int b_exists;
        int b_value;
        int c_exists;
        int c_value;
        int arr_exists;
        int arr_value;
        int s_exists;
        int s_value;
};

struct core_reloc_existence {
        struct {
                int x;
        } s;
        int arr[1];
        int a;
        struct {
                int b;
        };
        int c;
};

SEC("raw_tracepoint/sys_enter")
int test_core_existence(void *ctx)
{
        struct core_reloc_existence *in = (void *)&data.in;
        struct core_reloc_existence_output *out = (void *)&data.out;

        out->a_exists = bpf_core_field_exists(in->a);
        if (bpf_core_field_exists(struct core_reloc_existence, a))
                out->a_value = BPF_CORE_READ(in, a);
        else
                out->a_value = 0xff000001u;

        out->b_exists = bpf_core_field_exists(in->b);
        if (bpf_core_field_exists(struct core_reloc_existence, b))
                out->b_value = BPF_CORE_READ(in, b);
        else
                out->b_value = 0xff000002u;

        out->c_exists = bpf_core_field_exists(in->c);
        if (bpf_core_field_exists(struct core_reloc_existence, c))
                out->c_value = BPF_CORE_READ(in, c);
        else
                out->c_value = 0xff000003u;

        out->arr_exists = bpf_core_field_exists(in->arr);
        if (bpf_core_field_exists(struct core_reloc_existence, arr))
                out->arr_value = BPF_CORE_READ(in, arr[0]);
        else
                out->arr_value = 0xff000004u;

        out->s_exists = bpf_core_field_exists(in->s);
        if (bpf_core_field_exists(struct core_reloc_existence, s))
                out->s_value = BPF_CORE_READ(in, s.x);
        else
                out->s_value = 0xff000005u;

        return 0;
}