/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2022, Microsoft Corporation.
 *
 * Authors:
 *   Beau Belgrave <[email protected]>
 */

#ifndef _LINUX_USER_EVENTS_H
#define _LINUX_USER_EVENTS_H

#include <linux/list.h>
#include <linux/refcount.h>
#include <linux/mm_types.h>
#include <linux/workqueue.h>
#include <uapi/linux/user_events.h>

#ifdef CONFIG_USER_EVENTS
struct user_event_mm {
    struct list_head    mms_link;
    struct list_head    enablers;
    struct mm_struct    *mm;
    /* Used for one-shot lists, protected by event_mutex */
    struct user_event_mm    *next;
    refcount_t        refcnt;
    refcount_t        tasks;
    struct rcu_work        put_rwork;
};

extern void user_event_mm_dup(struct task_struct *t,
                  struct user_event_mm *old_mm);

extern void user_event_mm_remove(struct task_struct *t);

static inline void user_events_fork(struct task_struct *t,
                    unsigned long clone_flags)
{
    struct user_event_mm *old_mm;

    if (!t || !current->user_event_mm)
        return;

    old_mm = current->user_event_mm;

    if (clone_flags & CLONE_VM) {
        t->user_event_mm = old_mm;
        refcount_inc(&old_mm->tasks);
        return;
    }

    user_event_mm_dup(t, old_mm);
}

static inline void user_events_execve(struct task_struct *t)
{
    if (!t || !t->user_event_mm)
        return;

    user_event_mm_remove(t);
}

static inline void user_events_exit(struct task_struct *t)
{
    if (!t || !t->user_event_mm)
        return;

    user_event_mm_remove(t);
}
#else
static inline void user_events_fork(struct task_struct *t,
                    unsigned long clone_flags)
{
}

static inline void user_events_execve(struct task_struct *t)
{
}

static inline void user_events_exit(struct task_struct *t)
{
}
#endif /* CONFIG_USER_EVENTS */

#endif /* _LINUX_USER_EVENTS_H */