// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Bytedance */

#include "vmlinux.h"
#include <bpf/bpf_helpers.h>

__u64 percpu_array_elem_sum = 0;
__u64 percpu_hash_elem_sum = 0;
__u64 percpu_lru_hash_elem_sum = 0;
const volatile int nr_cpus;
const volatile int my_pid;

struct {
        __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
        __uint(max_entries, 1);
        __type(key, __u32);
        __type(value, __u64);
} percpu_array_map SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
        __uint(max_entries, 1);
        __type(key, __u64);
        __type(value, __u64);
} percpu_hash_map SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH);
        __uint(max_entries, 1);
        __type(key, __u64);
        __type(value, __u64);
} percpu_lru_hash_map SEC(".maps");

struct read_percpu_elem_ctx {
        void *map;
        __u64 sum;
};

static int read_percpu_elem_callback(__u32 index, struct read_percpu_elem_ctx *ctx)
{
        __u64 key = 0;
        __u64 *value;

        value = bpf_map_lookup_percpu_elem(ctx->map, &key, index);
        if (value)
                ctx->sum += *value;
        return 0;
}

SEC("tp/syscalls/sys_enter_getuid")
int sysenter_getuid(const void *ctx)
{
        struct read_percpu_elem_ctx map_ctx;

        if (my_pid != (bpf_get_current_pid_tgid() >> 32))
                return 0;

        map_ctx.map = &percpu_array_map;
        map_ctx.sum = 0;
        bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0);
        percpu_array_elem_sum = map_ctx.sum;

        map_ctx.map = &percpu_hash_map;
        map_ctx.sum = 0;
        bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0);
        percpu_hash_elem_sum = map_ctx.sum;

        map_ctx.map = &percpu_lru_hash_map;
        map_ctx.sum = 0;
        bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0);
        percpu_lru_hash_elem_sum = map_ctx.sum;

        return 0;
}

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