// SPDX-License-Identifier: GPL-2.0-only
#include <time.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>

struct timer {
        struct bpf_timer t;
};

struct lock {
        struct bpf_spin_lock l;
};

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, __u32);
        __type(value, struct timer);
} timers SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, __u32);
        __type(value, struct lock);
} locks SEC(".maps");

static int timer_cb(void *map, int *key, struct timer *timer)
{
        return 0;
}

static void timer_work(void)
{
        struct timer *timer;
        const int key = 0;

        timer  = bpf_map_lookup_elem(&timers, &key);
        if (timer) {
                bpf_timer_init(&timer->t, &timers, CLOCK_MONOTONIC);
                bpf_timer_set_callback(&timer->t, timer_cb);
                bpf_timer_start(&timer->t, 10E9, 0);
                bpf_timer_cancel(&timer->t);
        }
}

static void spin_lock_work(void)
{
        const int key = 0;
        struct lock *lock;

        lock = bpf_map_lookup_elem(&locks, &key);
        if (lock) {
                bpf_spin_lock(&lock->l);
                bpf_spin_unlock(&lock->l);
        }
}

SEC("?raw_tp/sys_enter")
int raw_tp_timer(void *ctx)
{
        timer_work();

        return 0;
}

SEC("?tp/syscalls/sys_enter_nanosleep")
int tp_timer(void *ctx)
{
        timer_work();

        return 0;
}

SEC("?kprobe")
int kprobe_timer(void *ctx)
{
        timer_work();

        return 0;
}

SEC("?perf_event")
int perf_event_timer(void *ctx)
{
        timer_work();

        return 0;
}

SEC("?raw_tp/sys_enter")
int raw_tp_spin_lock(void *ctx)
{
        spin_lock_work();

        return 0;
}

SEC("?tp/syscalls/sys_enter_nanosleep")
int tp_spin_lock(void *ctx)
{
        spin_lock_work();

        return 0;
}

SEC("?kprobe")
int kprobe_spin_lock(void *ctx)
{
        spin_lock_work();

        return 0;
}

SEC("?perf_event")
int perf_event_spin_lock(void *ctx)
{
        spin_lock_work();

        return 0;
}

const char LICENSE[] SEC("license") = "GPL";