diff --git a/open(add getdents).c b/open(add getdents).c
new file mode 100644
index 0000000..f657447
--- /dev/null
+++ b/open(add getdents).c	
@@ -0,0 +1,343 @@
+/*
+ *  linux/fs/open.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <utime.h>
+#include <sys/stat.h>
+#include <const.h>
+#include <linux/sched.h>
+#include <linux/tty.h>
+#include <linux/kernel.h>
+#include <asm/segment.h>
+
+int sys_ustat(int dev, struct ustat * ubuf)
+{
+	return -ENOSYS;
+}
+
+int sys_utime(char * filename, struct utimbuf * times)
+{
+	struct m_inode * inode;
+	long actime,modtime;
+
+	if (!(inode=namei(filename)))
+		return -ENOENT;
+	if (times) {
+		actime = get_fs_long((unsigned long *) &times->actime);
+		modtime = get_fs_long((unsigned long *) &times->modtime);
+	} else
+		actime = modtime = CURRENT_TIME;
+	inode->i_atime = actime;
+	inode->i_mtime = modtime;
+	inode->i_dirt = 1;
+	iput(inode);
+	return 0;
+}
+
+/*
+ * XXX should we use the real or effective uid?  BSD uses the real uid,
+ * so as to make this call useful to setuid programs.
+ */
+int sys_access(const char * filename,int mode)
+{
+	struct m_inode * inode;
+	int res, i_mode;
+
+	mode &= 0007;
+	if (!(inode=namei(filename)))
+		return -EACCES;
+	i_mode = res = inode->i_mode & 0777;
+	iput(inode);
+	if (current->uid == inode->i_uid)
+		res >>= 6;
+	else if (current->gid == inode->i_gid)
+		res >>= 6;
+	if ((res & 0007 & mode) == mode)
+		return 0;
+	/*
+	 * XXX we are doing this test last because we really should be
+	 * swapping the effective with the real user id (temporarily),
+	 * and then calling suser() routine.  If we do call the
+	 * suser() routine, it needs to be called last. 
+	 */
+	if ((!current->uid) &&
+	    (!(mode & 1) || (i_mode & 0111)))
+		return 0;
+	return -EACCES;
+}
+
+int sys_chdir(const char * filename)
+{
+	struct m_inode * inode;
+
+	if (!(inode = namei(filename)))
+		return -ENOENT;
+	if (!S_ISDIR(inode->i_mode)) {
+		iput(inode);
+		return -ENOTDIR;
+	}
+	iput(current->pwd);
+	current->pwd = inode;
+	return (0);
+}
+
+int sys_chroot(const char * filename)
+{
+	struct m_inode * inode;
+
+	if (!(inode=namei(filename)))
+		return -ENOENT;
+	if (!S_ISDIR(inode->i_mode)) {
+		iput(inode);
+		return -ENOTDIR;
+	}
+	iput(current->root);
+	current->root = inode;
+	return (0);
+}
+
+int sys_chmod(const char * filename,int mode)
+{
+	struct m_inode * inode;
+
+	if (!(inode=namei(filename)))
+		return -ENOENT;
+	if ((current->euid != inode->i_uid) && !suser()) {
+		iput(inode);
+		return -EACCES;
+	}
+	inode->i_mode = (mode & 07777) | (inode->i_mode & ~07777);
+	inode->i_dirt = 1;
+	iput(inode);
+	return 0;
+}
+
+int sys_chown(const char * filename,int uid,int gid)
+{
+	struct m_inode * inode;
+
+	if (!(inode=namei(filename)))
+		return -ENOENT;
+	if (!suser()) {
+		iput(inode);
+		return -EACCES;
+	}
+	inode->i_uid=uid;
+	inode->i_gid=gid;
+	inode->i_dirt=1;
+	iput(inode);
+	return 0;
+}
+
+int sys_open(const char * filename,int flag,int mode)
+{
+	struct m_inode * inode;
+	struct file * f;
+	int i,fd;
+
+	mode &= 0777 & ~current->umask;
+	for(fd=0 ; fd<NR_OPEN ; fd++)
+		if (!current->filp[fd])
+			break;
+	if (fd>=NR_OPEN)
+		return -EINVAL;
+	current->close_on_exec &= ~(1<<fd);
+	f=0+file_table;
+	for (i=0 ; i<NR_FILE ; i++,f++)
+		if (!f->f_count) break;
+	if (i>=NR_FILE)
+		return -EINVAL;
+	(current->filp[fd]=f)->f_count++;
+	if ((i=open_namei(filename,flag,mode,&inode))<0) {
+		current->filp[fd]=NULL;
+		f->f_count=0;
+		return i;
+	}
+/* ttys are somewhat special (ttyxx major==4, tty major==5) */
+	if (S_ISCHR(inode->i_mode))
+		if (MAJOR(inode->i_zone[0])==4) {
+			if (current->leader && current->tty<0) {
+				current->tty = MINOR(inode->i_zone[0]);
+				tty_table[current->tty].pgrp = current->pgrp;
+			}
+		} else if (MAJOR(inode->i_zone[0])==5)
+			if (current->tty<0) {
+				iput(inode);
+				current->filp[fd]=NULL;
+				f->f_count=0;
+				return -EPERM;
+			}
+/* Likewise with block-devices: check for floppy_change */
+	if (S_ISBLK(inode->i_mode))
+		check_disk_change(inode->i_zone[0]);
+	f->f_mode = inode->i_mode;
+	f->f_flags = flag;
+	f->f_count = 1;
+	f->f_inode = inode;
+	f->f_pos = 0;
+	return (fd);
+}
+
+int sys_creat(const char * pathname, int mode)
+{
+	return sys_open(pathname, O_CREAT | O_TRUNC, mode);
+}
+
+int sys_close(unsigned int fd)
+{	
+	struct file * filp;
+
+	if (fd >= NR_OPEN)
+		return -EINVAL;
+	current->close_on_exec &= ~(1<<fd);
+	if (!(filp = current->filp[fd]))
+		return -EINVAL;
+	current->filp[fd] = NULL;
+	if (filp->f_count == 0)
+		panic("Close: file count is 0");
+	if (--filp->f_count)
+		return (0);
+	iput(filp->f_inode);
+	return (0);
+}
+int find_entry1(struct m_inode ** dir,int find_node,struct dir_entry ** res_dir){
+	int entries;
+	int block,i;
+	struct buffer_head * bh;
+	struct dir_entry * de;
+	struct super_block * sb;
+	entries = (*dir)->i_size / (sizeof (struct dir_entry));
+	*res_dir = NULL;
+	if (!(block = (*dir)->i_zone[0]))
+		return NULL;
+	if (!(bh = bread((*dir)->i_dev,block)))
+		return NULL;
+	i = 0;
+	de = (struct dir_entry *) bh->b_data;
+	while (i < entries) {
+		if ((char *)de >= BLOCK_SIZE+bh->b_data) {
+			brelse(bh);
+			bh = NULL;
+			if (!(block = bmap(*dir,i/DIR_ENTRIES_PER_BLOCK)) ||
+			    !(bh = bread((*dir)->i_dev,block))) {
+				i += DIR_ENTRIES_PER_BLOCK;
+				continue;
+			}
+			de = (struct dir_entry *) bh->b_data;
+		}
+		if (de->inode == find_node) {
+			*res_dir = de;
+			return 0;
+		}
+		de++;
+		i++;
+	}
+	brelse(bh);
+	return -1;
+}
+long sys_getcwd(char *buf,size_t size){
+	int entries;
+	int block,i;
+	int num = 19;
+	char s[20][NAME_LEN];
+	struct buffer_head * bh;
+	struct dir_entry * de;
+	struct dir_entry * res_dir;
+	struct super_block * sb;
+	struct m_inode * dir =current->pwd;
+	struct m_inode * olddir  =NULL;
+	while(1){
+		olddir = dir;
+		if (olddir==current->root)
+			break;
+		if (!dir->i_zone[0])
+			return NULL;
+		if(!(bh = bread(dir->i_dev,dir->i_zone[0])))//获得i节点指向的数据块
+			return NULL;
+		de = (struct dir_entry *) bh->b_data;
+		int find = de->inode;
+		if (!(dir = iget(dir->i_dev,(de+1)->inode))){//dir更新并判断错误
+			return NULL;
+		}
+		if(find_entry1(&dir,find,&res_dir)==-1){
+			printk("getcwd error\n");
+			return NULL;
+		}
+		strcpy(s[num--],res_dir->name);
+	}
+	char *buf1;
+	char *buf3 = buf1;
+	for(i=num+1;i<=19;i++){
+		*buf3 = '/';
+		*buf3++;
+		char *w = s[i];
+		while(*w){
+			*buf3 = (*w++);
+			*buf3++;
+		}
+	}
+	int len = strlen(buf1);
+	if(!buf)	buf = (char *)malloc(len);
+	char *buf2 = buf;
+	int j;
+	for(j=0;j<len;j++)
+		put_fs_byte(*(buf1++),buf2++);
+	return buf;
+}
+int sys_getdents(unsigned int fd,struct linux_dirent *dirp,unsigned int count){
+	struct m_inode *dir = current->filp[fd]->f_inode;
+	/*if(!(dir= current->filp[fd]->f_inode))
+		return -1;*/
+	int entries;
+	int block,i;
+	struct buffer_head * bh;
+	struct dir_entry * de;
+	struct super_block * sb;
+	struct linux_dirent * cur = (struct linux_dirent *)malloc(count) ;
+	char *oldcur = (char *)cur;
+	entries = dir->i_size / (sizeof (struct dir_entry));
+	if (!(block = dir->i_zone[0]))
+		return -1;
+	if (!(bh = bread(dir->i_dev,block)))
+		return -1;
+	i = 0;
+	int fixsize = sizeof(long)+sizeof(off_t)+sizeof(unsigned short);
+	int pos = 0;
+	de = (struct dir_entry *) bh->b_data;
+	int nread=0;
+	while (i < entries) {
+		if ((char *)de >= BLOCK_SIZE+bh->b_data) {
+			brelse(bh);
+			bh = NULL;
+			if (!(block = bmap(dir,i/DIR_ENTRIES_PER_BLOCK)) ||
+			    !(bh = bread(dir->i_dev,block))) {
+				i += DIR_ENTRIES_PER_BLOCK;
+				continue;
+			}
+			de = (struct dir_entry *) bh->b_data;
+		}
+		cur->d_ino = de->inode;
+		cur->d_off = pos;
+		strcpy(cur->d_name,de->name);
+		cur->d_reclen = fixsize+sizeof(de->name);
+		pos += cur->d_reclen;
+		nread+=sizeof(de->name);
+		de++;
+		char *w = (char *)cur;
+		w = w+cur->d_reclen;
+		cur = (struct linux_dirent *)w;
+		i++;
+	}
+	brelse(bh);
+	char *s = (char *)dirp;
+	int j=0;	
+	for(j;j<pos;j++)
+		put_fs_byte(*(oldcur++),s++);
+	return pos;
+}