#include "sys.h"
#include "con.h"
#include "file.h"
#include "inode.h"
#include "proc.h"

       /*
	* Access ciosw to open a character device
	*/
copen(dev, mode)
	int dev, mode;
	{
	(*ciosw[cmajor(dev)].open)(dev, mode);
	}

       /*
	* Access ciosw to close a character device
	*/
cclose(dev, mode)
	int dev, mode;
	{
	(*ciosw[cmajor(dev)].close)(dev, mode);
	}

       /*
	* Access ciosw to read a character device
	*/
cread(dev)
	int dev;
	{
	(*ciosw[cmajor(dev)].read)(dev);
	}

       /*
	* Access ciosw to write a character device
	*/
cwrite(dev)
	int dev;
	{
	(*ciosw[cmajor(dev)].write)(dev);
	}

       /*
	* Access ciosw to sgtty a character device
	*/
cmode(fd, addr, flag)
	int fd, flag;
	char *addr;
	{
	static struct file *fp;
	static struct inode *ip;
	static int dev;

	if ((fp = ofile(fd)) == NULL)
		return;
	ip = fp->inode;
	if ((ip->mode & ITYPE) != ICIO)
		{
		u.error = ENOTTY;
		return;
		}
	if (!valid(addr, 6))	/* malloc.c */
		return;
	u.base = addr;
	u.segflg = USEG;
	dev = ip->addr[0];
	(*ciosw[cmajor(dev)].mode)(dev, flag);
	}

       /*
	* Gtty system call. Notice that the calling conventions
	* for the devive sgtty routine are not unix standard.
	*/
gtty(fd, addr)
	int fd;
	char *addr;
	{
	cmode(fd, addr, READ);
	}

       /*
	* Stty system call. Notice that the calling conventions
	* for the devive sgtty routine are not unix standard.
	*/
stty(fd, addr)
	int fd;
	char *addr;
	{
	cmode(fd, addr, WRITE);
	}

       /*
	* Extract the major device number
	*/
cmajor(dev)
	unsigned dev;
	{
	if ((dev >>= 8) >= ncdev)
		return (0); /* nodev sets u.error = ENXIO */
	return (dev);
	}

       /*
	* Do-nothing entry for biosw or ciosw
	*/
nulldev()
	{
	}

       /*
	* Error entry for biosw or ciosw
	*/
nodev()
	{
	u.error = ENXIO;
	}

       /*
	* Null write. Pretend to write all characters.
	*/
nullwrite()
	{
	u.count = 0;
	}