linux 0.11 ÄÚºËѧϰ ioctl.c

/*
 * ioctl.c ÎļþʵÏÖÁËÊäÈë/Êä³ö¿ØÖÆϵͳµ÷ÓÃioctl()£¬¸Ãº¯Êý
 * Ö÷ÒªÊǵ÷Óú¯Êýtty_ioctl()¶ÔÖն˵ÄIO½øÐпØÖÆ
 */
/*
 *  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);
/* ¶¨ÒåϵͳÖÐÉ豸ÖÖÊý */
#define NRDEVS ((sizeof (ioctl_table))/(sizeof (ioctl_ptr)))
/* ioctl ²Ù×÷º¯ÊýÖ¸Õë±í */
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 */

/* ÊäÈëÊä³ö¿ØÖƺ¯Êý */
int sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
{
struct file * filp;
int dev,mode;
// Èç¹ûÎļþÃèÊö·û³¬³ö¿É´ò¿ªµÄÎļþÊý£¬»òÕ߶ÔÓ¦ÃèÊö·ûµÄÎļþ½á¹¹Ö¸ÕëΪ¿Õ£¬Ôò·µ»Ø³ö´íÂë
if (fd >= NR_OPEN || !(filp = current->filp[fd]))
return -EBADF;
// È¡¶ÔÓ¦ÎļþµÄÊôÐÔ
mode=filp->f_inode->i_mode;
// Èç¹û¸ÃÎļþ²»ÊÇ×Ö·ûÎļþ£¬Ò²²»ÊÇ¿éÉ豸Îļþ£¬Ôò·µ»Ø³ö´íÂë
if (!S_ISCHR(mode) && !S_ISBLK(mode))
return -EINVAL;
// ´Ó×Ö·û»ò¿éÉ豸ÎļþµÄi ½ÚµãÖÐÈ¡É豸ºÅ¡£Èç¹ûÉ豸ºÅ´óÓÚϵͳÏÖÓеÄÉ豸Êý£¬Ôò·µ»Ø³ö´íºÅ
dev = filp->f_inode->i_zone[0];
if (MAJOR(dev) >= NRDEVS)
return -ENODEV;
// Èç¹û¸ÃÉ豸ÔÚioctl º¯ÊýÖ¸Õë±íÖÐûÓжÔÓ¦º¯Êý
if (!ioctl_table[MAJOR(dev)])
return -ENOTTY;
// ·ñÔò·µ»Øʵ¼Êioctl º¯Êý·µ»ØÂë
return ioctl_table[MAJOR(dev)](dev,cmd,arg);
}
²Î¿¼¡¶linuxÄÚºËÍêȫעÊÍ¡·ºÍÍøÉÏÏà¹ØÎÄÕÂ