diff --git a/Makefile b/Makefile
index 38357508208d5f81a3cffb27dc6090f31911de01..1b3b33e47aeea8f799560cc7405c0d167b3d7aa8 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ linux.img : tools/build bootsect setup kernel/system
 tools/build : tools/build.c
 		gcc -o $@ $<
 
-kernel/system : kernel/head.S kernel/*.c mm/*.c kernel/blk_drv/*.c
+kernel/system : kernel/head.S kernel/*.c mm/*.c kernel/blk_drv/*.c fs/*.c
 		cd kernel; make system; cd ..
 
 bootsect : bootsect.o
diff --git a/fs/Makefile b/fs/Makefile
index 3b1cea3c1d2f8e8c3ec97cf56347d2da10e1b06f..bf064136bc5b906185553672c77e633ed12cccc9 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -3,7 +3,7 @@ LD  := ld
 CCFLAG := -I../include -nostdinc -ffreestanding -Wall -fomit-frame-pointer -fno-stack-protector -fno-pic -c -m32
 LDFLAG := -Ttext 0x0 -s --oformat binary -m elf_i386
 INCDIR := ../include
-OBJS   := read_write.o buffer.o super.o open.o file_table.o inode.o
+OBJS   := read_write.o buffer.o super.o open.o file_table.o inode.o namei.o
 
 fs.o : $(OBJS)
 	$(LD) -m elf_i386 -r -o $@ $^
@@ -26,6 +26,9 @@ file_table.o : file_table.c
 inode.o : inode.c
 	$(GCC) $(CCFLAG) -o $@ $<
 
+namei.o : namei.c
+	$(GCC) $(CCFLAG) -o $@ $<
+
 clean : 
 	rm *.o
 
diff --git a/fs/namei.c b/fs/namei.c
new file mode 100644
index 0000000000000000000000000000000000000000..f8a513dd3885ccbcd26664b2f6f0e630857ef7db
--- /dev/null
+++ b/fs/namei.c
@@ -0,0 +1,172 @@
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <asm/segment.h>
+
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <const.h>
+#include <sys/stat.h>
+
+#define MAY_EXEC 1
+#define MAY_WRITE 2
+#define MAY_READ 4
+
+static int permission(struct m_inode * inode,int mask) {
+    return 1;
+}
+
+static int match(int len,const char * name,struct dir_entry * de) {
+    register int same __asm__("ax");
+    if (!de || !de->inode || len > NAME_LEN)
+        return 0;
+
+    if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
+        return 1;
+
+    if (len < NAME_LEN && de->name[len])
+        return 0;
+
+    __asm__("cld\n\t"
+            "fs ; repe ; cmpsb\n\t"
+            "setz %%al"
+            :"=a" (same)
+            :"a" (0),"S" ((long) name),"D" ((long) de->name),"c" (len):);
+
+    return same;
+}
+
+static struct buffer_head * find_entry(struct m_inode ** dir,
+        const char * name, int namelen, struct dir_entry ** res_dir) {
+    int entries;
+    int block,i;
+    struct buffer_head * bh;
+    struct dir_entry * de;
+    struct super_block * psb;
+
+    entries = (*dir)->i_size / (sizeof (struct dir_entry));
+    *res_dir = NULL;
+
+    if (namelen==2 && get_fs_byte(name)=='.' && get_fs_byte(name+1)=='.') {
+        if ((*dir) == current->root)
+            namelen=1;
+    }
+
+    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 (match(namelen,name,de)) {
+            *res_dir = de;
+            return bh;
+        }
+        de++;
+        i++;
+    }
+    brelse(bh);
+    return NULL;
+}
+
+static struct m_inode * get_dir(const char * pathname, struct m_inode * inode) {
+    char c;
+    const char * thisname;
+    struct buffer_head * bh;
+    int namelen,inr;
+    struct dir_entry * de;
+    struct m_inode * dir;
+
+    if (!inode) {
+        inode = current->pwd;
+        inode->i_count++;
+    }
+    if ((c=get_fs_byte(pathname))=='/') {
+        //iput(inode);
+        inode = current->root;
+        pathname++;
+        inode->i_count++;
+    }
+
+    while (1) {
+        thisname = pathname;
+        if (!S_ISDIR(inode->i_mode) || !permission(inode,MAY_EXEC)) {
+            // iput(inode);
+            return NULL;
+        }
+        for(namelen=0;(c=get_fs_byte(pathname++))&&(c!='/');namelen++)
+            /* nothing */ ;
+        if (!c)
+            return inode;
+
+        if (!(bh = find_entry(&inode,thisname,namelen,&de))) {
+            // iput(inode);
+            return NULL;
+        }
+
+        inr = de->inode;
+        brelse(bh);
+        dir = inode;
+        if (!(inode = iget(dir->i_dev,inr))) {
+            //iput(dir);
+            return NULL;
+        }
+    }
+    
+    return NULL;
+}
+
+static struct m_inode * dir_namei(const char * pathname,
+        int * namelen, const char ** name, struct m_inode * base) {
+    char c;
+    const char * basename;
+    struct m_inode * dir;
+
+    if (!(dir = get_dir(pathname,base)))
+        return NULL;
+
+    basename = pathname;
+    while ((c = get_fs_byte(pathname++))) {
+        if (c == '/')
+            basename = pathname;
+    }
+
+    *namelen = pathname-basename-1;
+    *name = basename;
+
+    return dir;
+}
+
+int open_namei(const char * pathname, int flag, int mode,
+        struct m_inode ** res_inode) {
+    const char * basename;
+    int inr,dev,namelen;
+    struct m_inode * dir, *inode;
+    struct buffer_head * bh;
+    struct dir_entry * de;
+
+    if ((flag & O_TRUNC) && !(flag & O_ACCMODE))
+        flag |= O_WRONLY;
+    mode &= 0777 & ~current->umask;
+    mode |= I_REGULAR;
+    if (!(dir = dir_namei(pathname,&namelen,&basename,NULL)))
+        return -ENOENT;
+
+    bh = find_entry(&dir,basename,namelen,&de);
+    if (!bh) {
+        return -EINVAL;
+    }
+
+    inr = de->inode;
+    dev = dir->i_dev;
+    brelse(bh);
+
+
+    inode = iget(dev,inr);
+    *res_inode = inode;
+    return 0;
+}
+
diff --git a/fs/open.c b/fs/open.c
index 538df2200ba8123c8ec0fa5a9a3fb037915d7f94..bdb97e4cf9edb6812c9ed187098b01158d5ee2f6 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -5,9 +5,47 @@
 #include <linux/tty.h>
 #include <linux/kernel.h>
 
+#include <sys/stat.h>
+
 #include <asm/segment.h>
 
 int sys_open(const char * filename,int flag,int mode) {
-    printk("try to open %s\n", filename);
-    return 0;
+    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;
+    }
+
+    if (S_ISCHR(inode->i_mode)) {
+        printk("open char dev %d\n", fd);
+    }
+
+    f->f_mode = inode->i_mode;
+    f->f_flags = flag;
+    f->f_count = 1;
+    f->f_inode = inode;
+    f->f_pos = 0;
+
+    return fd;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8fb66451dc0f62d92419e45f4a92c2daca7bb37e..8d045395faa62df5fbaad0e88bff6685aa474c13 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -124,6 +124,12 @@ struct d_super_block {
     unsigned short s_magic;
 };
 
+struct dir_entry {
+    unsigned short inode;
+    char name[NAME_LEN];
+};
+
+extern struct m_inode inode_table[NR_INODE];
 extern struct file file_table[NR_FILE];
 extern struct m_inode * iget(int dev,int nr);
 
diff --git a/include/sys/stat.h b/include/sys/stat.h
index cf474a0d551ea9dee27970e74d870b16540531d4..131cf5dd45ff251ff26a4764e0e982a67a57d3fa 100644
--- a/include/sys/stat.h
+++ b/include/sys/stat.h
@@ -3,4 +3,12 @@
 
 #include <sys/types.h>
 
+#define S_IFMT  00170000
+#define S_IFDIR  0040000
+#define S_IFCHR  0020000
+
+
+#define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)
+#define S_ISCHR(m)      (((m) & S_IFMT) == S_IFCHR)
+
 #endif