// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2020 Oplus. All rights reserved.
 */


#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include <linux/uaccess.h>
#include <../fs/proc/internal.h>
#include "fg_uid.h"

#define FG_RW (S_IWUSR|S_IRUSR|S_IWGRP|S_IRGRP|S_IWOTH|S_IROTH)

struct fg_info fginfo = {
    .fg_num = 0,
    .fg_uids = -555,
};

static struct proc_dir_entry *fg_dir;

bool is_fg(int uid)
{
    bool ret = false;
    if (uid == fginfo.fg_uids)
	ret = true;
    return ret;
}
EXPORT_SYMBOL_GPL(is_fg);

static int fg_uids_show(struct seq_file *m, void *v)
{
    seq_printf(m, "fg_uids: %d\n", fginfo.fg_uids);
    return 0;
}

static int fg_uids_open(struct inode *inode, struct file *filp)
{
   return single_open(filp, fg_uids_show, inode);
}

#ifdef CONFIG_OPLUS_BINDER_STRATEGY
extern void oblist_dequeue_topapp_change(uid_t topuid);
#endif
static ssize_t fg_uids_write(struct file *file, const char __user *buf,
                        size_t count, loff_t *ppos)
{
    char buffer[MAX_ARRAY_LENGTH];
    int err = 0;

    memset(buffer, 0, sizeof(buffer));
    if (count > sizeof(buffer) - 1)
        count = sizeof(buffer) - 1;
    if (copy_from_user((void *)buffer, buf, count)) {
        err = -EFAULT;
        goto out;
    }

    fginfo.fg_uids = simple_strtol(buffer, NULL, 0);
    fginfo.fg_num = 1;
#ifdef CONFIG_OPLUS_BINDER_STRATEGY
	if (fginfo.fg_uids > 0)
		oblist_dequeue_topapp_change(fginfo.fg_uids);
#endif
out:
    return err < 0 ? err : count;
}

static const struct file_operations proc_fg_uids_operations = {
   .open       = fg_uids_open,
   .read       = seq_read,
   .write      = fg_uids_write,
   .llseek     = seq_lseek,
   .release    = single_release,
};

static void uids_proc_fs_init(struct proc_dir_entry *p_parent)
{
    struct proc_dir_entry *p_temp;

    if (!p_parent)
        goto out_p_temp;

    p_temp = proc_create(FS_FG_UIDS, FG_RW, p_parent, &proc_fg_uids_operations);
    if (!p_temp)
        goto out_p_temp;

out_p_temp:
    return ;
}

static int __init fg_uids_init(void)
{
    struct proc_dir_entry *p_parent;

    p_parent = proc_mkdir(FS_FG_INFO_PATH, fg_dir);
    if (!p_parent){
        return -ENOMEM;
    }
    uids_proc_fs_init(p_parent);
    return 0;
}

static  void __exit fg_uids_exit(void)
{
    if (!fg_dir)
        return ;

    remove_proc_entry(FS_FG_UIDS, fg_dir);
}

module_init(fg_uids_init);
module_exit(fg_uids_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("OPLUS");
MODULE_DESCRIPTION("optimize foreground process to promote performance");