#include <linux/kernel.h>    // printk()
#include <linux/syscalls.h>
#include "defines.h"
#include "kfile.h"
#include "ksync.h"

static unsigned int g_nLocks = 0;

/////////////////////////////////////////////////////////////////////////////

static long _vfs_ioctl(struct file *pf, unsigned int cmd, unsigned long arg)
{
	int ret = -ENOTTY;

	if(pf->f_op->unlocked_ioctl)
	{
		ret = pf->f_op->unlocked_ioctl(pf, cmd, arg);

		if(ret == -ENOIOCTLCMD)
			ret = -ENOTTY;
	}
 
 	return ret;
}

/////////////////////////////////////////////////////////////////////////////

struct file* kf_open(const char *path, int flags, int rights)
{
    struct file *pf = NULL;
    mm_segment_t oldfs;
    int err = 0;

    oldfs = get_fs();
    set_fs(get_ds());
    pf = filp_open(path, flags, rights);
    set_fs(oldfs);

    if(IS_ERR(pf))
    {
        err = PTR_ERR(pf);
		set_fs(oldfs);
        return NULL;
    }

    return pf;
}

/////////////////////////////////////////////////////////////////////////////

struct file* kf_open_locked(const char *path, int flags, int rights)
{
	struct file *pf = NULL;

	kfile_lock();
	if(!(pf = kf_open(path, flags, rights)))
		kfile_unlock();
	++g_nLocks;
	return pf;
}

/////////////////////////////////////////////////////////////////////////////

void kf_close(struct file *pf)
{
	if(pf)
	{
    	filp_close(pf, NULL);
    	if(g_nLocks > 0)
    	{
    		--g_nLocks;
			kfile_unlock();
    	}
    }
}

/////////////////////////////////////////////////////////////////////////////

int kf_read(struct file *pf, unsigned long long offset, unsigned char *data, unsigned int size)
{
	int ret;
	mm_segment_t oldfs;

	oldfs = get_fs();
	set_fs(get_ds());

	ret = vfs_read(pf, data, size, &offset);

	set_fs(oldfs);
	return ret;
}

/////////////////////////////////////////////////////////////////////////////

int kf_write(struct file *pf, unsigned long long offset, unsigned char *data, unsigned int size)
{
	int ret;
	mm_segment_t oldfs;

	oldfs = get_fs();
	set_fs(get_ds());

	ret = vfs_write(pf, data, size, &offset);

	set_fs(oldfs);
	return ret;
}

/////////////////////////////////////////////////////////////////////////////

long kf_ioctl(struct file *pf, unsigned int cmd, unsigned long arg)
{
	long ret;
	mm_segment_t oldfs;

	oldfs = get_fs();
	set_fs(get_ds());

	ret = _vfs_ioctl(pf, cmd, arg);

	set_fs(oldfs);
	return ret;
}

/////////////////////////////////////////////////////////////////////////////

int kf_sync(struct file *pf)
{
	vfs_fsync(pf, 0);
	return 0;
}