/* *  linux/fs/ioctl.c * *  (C) 1991  Linus Torvalds *//* #include <string.h>*/#include <errno.h>#include <sys/stat.h>#include <linux/sched.h>extern int tty_ioctl(int dev, int cmd, int arg);typedef int (*ioctl_ptr)(int dev,int cmd,int arg);#define NRDEVS ((sizeof (ioctl_table))/(sizeof (ioctl_ptr)))static ioctl_ptr ioctl_table[]={	NULL,		/* nodev */	NULL,		/* /dev/mem */	NULL,		/* /dev/fd */	NULL,		/* /dev/hd */	tty_ioctl,	/* /dev/ttyx */	tty_ioctl,	/* /dev/tty */	NULL,		/* /dev/lp */	NULL};		/* named pipes */	int sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg){		struct file * filp;	int dev,mode;	if (fd >= NR_OPEN || !(filp = current->filp[fd]))		return -EBADF;	mode=filp->f_inode->i_mode;	if (!S_ISCHR(mode) && !S_ISBLK(mode))		return -EINVAL;	dev = filp->f_inode->i_zone[0];	if (MAJOR(dev) >= NRDEVS)		return -ENODEV;	if (!ioctl_table[MAJOR(dev)])		return -ENOTTY;	return ioctl_table[MAJOR(dev)](dev,cmd,arg);}