// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */

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

#ifndef EBUSY
#define EBUSY 16
#endif

char _license[] SEC("license") = "GPL";
int nr_del_errs = 0;
int test_pid = 0;

struct {
        __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
        __uint(map_flags, BPF_F_NO_PREALLOC);
        __type(key, int);
        __type(value, long);
} map_a SEC(".maps");

struct {
        __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
        __uint(map_flags, BPF_F_NO_PREALLOC);
        __type(key, int);
        __type(value, long);
} map_b SEC(".maps");

SEC("fentry/bpf_local_storage_update")
int BPF_PROG(on_update)
{
        struct task_struct *task = bpf_get_current_task_btf();
        long *ptr;

        if (!test_pid || task->pid != test_pid)
                return 0;

        /* This will succeed as there is no real deadlock */
        ptr = bpf_task_storage_get(&map_a, task, 0,
                                   BPF_LOCAL_STORAGE_GET_F_CREATE);
        if (ptr) {
                int err;

                *ptr += 1;
                err = bpf_task_storage_delete(&map_a, task);
                if (err == -EBUSY)
                        nr_del_errs++;
        }

        /* This will succeed as there is no real deadlock */
        ptr = bpf_task_storage_get(&map_b, task, 0,
                                   BPF_LOCAL_STORAGE_GET_F_CREATE);
        if (ptr)
                *ptr += 1;

        return 0;
}

SEC("tp_btf/sys_enter")
int BPF_PROG(on_enter, struct pt_regs *regs, long id)
{
        struct task_struct *task;
        long *ptr;

        task = bpf_get_current_task_btf();
        if (!test_pid || task->pid != test_pid)
                return 0;

        ptr = bpf_task_storage_get(&map_a, task, 0,
                                   BPF_LOCAL_STORAGE_GET_F_CREATE);
        if (ptr && !*ptr)
                *ptr = 200;

        ptr = bpf_task_storage_get(&map_b, task, 0,
                                   BPF_LOCAL_STORAGE_GET_F_CREATE);
        if (ptr && !*ptr)
                *ptr = 100;
        return 0;
}