中文版的个人文件系统

时间：2006-08-25 来源：lonelyair

#include "hello.h"

struct inode * hello_get_inode(struct super_block *, int, struct hello_dir_entry *);

/*这个函数是直接从linux复制过来的，作用就是显示目录里的文件名，没有这个
函数也行只是你用ls、dir命令看不到目录下的文件。*/
int hello_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
printk("hello_readdir\n");
struct hello_dir_entry * de;
unsigned int ino;
int i;
struct inode *inode = filp->;f_dentry->;d_inode;

ino = inode->;i_ino;
de = (struct hello_dir_entry *) inode->;u.generic_ip;
if (!de)
return -EINVAL;
i = filp->;f_pos;
switch (i) {
case 0:
if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
return 0;
i++;
filp->;f_pos++;
/* fall through */
case 1:
if (filldir(dirent, "..", 2, i,
      filp->;f_dentry->;d_parent->;d_inode->;i_ino,
      DT_DIR) < 0)
return 0;
i++;
filp->;f_pos++;
/* fall through */
default:
de = de->;subdir;
i -= 2;
for (;;) {
if (!de)
return 1;
if (!i)
break;
de = de->;next;
i--;
}

do {
if (filldir(dirent, de->;name, de->;namelen, filp->;f_pos,
      de->;low_ino, de->;mode >;>; 12) < 0)
return 0;
filp->;f_pos++;
de = de->;next;
} while (de);
}
return 1;
}

int hello_d_revalidate(struct dentry *res, int i){printk("d_revalidate\n");return 0;}
int hello_d_hash(struct dentry *res, struct qstr *name){printk("d_hash\n");return 0;}
int hello_d_compare(struct dentry *res, struct qstr *name, struct qstr *old)
{printk("d_compare\n");return 0;}
int hello_d_delete(struct dentry *res){printk("d_delete\n");return 0;}
void hello_d_release(struct dentry *res){printk("d_release\n");}
void hello_d_iput(struct dentry *res, struct inode *inode){printk("d_iput\n");}

struct dentry_operations hello_lookup_dops = {
/*d_revalidate: hello_d_revalidate,
d_hash: hello_d_hash,
d_compare: hello_d_compare,*/
d_delete: hello_d_delete,
d_release: hello_d_release,
/*d_iput: hello_d_iput*/
};

/*读文件节点，这个函数是被real_lookup函数调用的，具体调用是这里dir->;i_op->;lookup(dir, dentry);作用是从磁盘读文件节点填充inode结构。我这里用hello_dir_entry结构填充的*/

struct dentry *hello_lookup(struct inode * dir, struct dentry *dentry)
{
struct inode *inode;
struct hello_dir_entry * de;
int error;

error = -ENOENT;
inode = NULL;
de = (struct hello_dir_entry *) dir->;u.generic_ip;
if (de) {
for (de = de->;subdir; de ; de = de->;next) {
if (!de || !de->;low_ino)
continue;
if (de->;namelen != dentry->;d_name.len)
continue;
if (!memcmp(dentry->;d_name.name, de->;name, de->;namelen)) {
int ino = de->;low_ino;
error = -EINVAL;
inode = hello_get_inode(dir->;i_sb, ino, de);
break;
}
}
}

if (inode) {
dentry->;d_op = &hello_lookup_dops;
d_add(dentry, inode);
return NULL;
}
return ERR_PTR(error);
}
/************************************************************************************************************/
static struct inode_operations hello_root_inode_operations = {
lookup: hello_lookup,
};

static struct file_operations hello_file_operations = {
readdir: hello_readdir,
};

struct hello_dir_entry hello_root = {
low_ino: HELLO_ROOT_INO,
namelen: 5,
name: "/hello",
mode: S_IFDIR | S_IRUGO | S_IXUGO,
nlink: 2,
hello_iops: &hello_root_inode_operations,
hello_fops: &hello_file_operations,
parent: &hello_root,
};

/*填充inode结构*/
struct inode * hello_get_inode(struct super_block * sb, int ino,
struct hello_dir_entry * de)
{
printk("hello_get_inode\n");
struct inode * inode;

de_get(de);
inode = iget(sb, ino);
if (!inode)
goto out_fail;
inode->;u.generic_ip = (void *) de;
if (de) {
if (de->;mode) {
inode->;i_mode = de->;mode;
inode->;i_uid = de->;uid;
inode->;i_gid = de->;gid;
}
if (de->;size)
inode->;i_size = de->;size;
if (de->;nlink)
inode->;i_nlink = de->;nlink;
if (de->;owner)
__MOD_INC_USE_COUNT(de->;owner);
if (de->;hello_iops)
inode->;i_op = de->;hello_iops;
if (de->;hello_fops)
inode->;i_fop = de->;hello_fops;
}

out:
return inode;

out_fail:
de_put(de);
goto out;
}

/***********************************************************************************************************/

void d_instantiate(struct dentry *entry, struct inode * inode)
{
printk("d_instantiate\n");
if (!list_empty(&entry->;d_alias)) BUG();
spin_lock(&dcache_lock);
if (inode)
list_add(&entry->;d_alias, &inode->;i_dentry);
entry->;d_inode = inode;
spin_unlock(&dcache_lock);
}
/*创建根目录的dentry结构*/

struct dentry * d_alloc_root(struct inode * root_inode)
{
struct dentry *res = NULL;
printk("d_alloc_root\n");
if (root_inode) {
res = d_alloc(NULL, &(const struct qstr) { "/", 1, 0 });
if (res) {
res->;d_sb = root_inode->;i_sb;
res->;d_parent = res;
d_instantiate(res, root_inode);/*把根目录的inode结构安装到dentry结构里*/
}
}
return res;
}

void force_delete(struct inode *inode)
{
printk("force_delete\n");
struct hello_dir_entry *de = inode->;u.generic_ip;

if (atomic_read(&inode->;i_count) == 1)
inode->;i_nlink = 0;
if (atomic_dec_and_test(&de->;count))
printk("hello_root.count: %d\n", atomic_read(&de->;count));
}

static void hello_delete_inode(struct inode *inode)
{
printk("hello_delete_inode\n");
struct hello_dir_entry *de = inode->;u.generic_ip;
inode->;i_state = I_CLEAR;
/*if (de) {
if (de->;owner)
__MOD_DEC_USE_COUNT(de->;owner);
de_put(de);
}*/
}

static void hello_read_inode(struct inode * inode)
{
printk("hello_read_inode\n");
inode->;i_mtime = inode->;i_atime = inode->;i_ctime = CURRENT_TIME;
}

static int hello_statfs(struct super_block *sb, struct statfs *buf)
{
printk("hello_statfs\n");
return 0;
}

void hello_write_super(struct super_block *s)
{
printk("write_super\n");
}

static struct super_operations hello_sops = {
read_inode: hello_read_inode,
put_inode: force_delete,
delete_inode: hello_delete_inode,
write_super: hello_write_super,
/*statfs: hello_statfs,*/
};

struct dentry_operations hello_dops = {
/*d_revalidate: hello_d_revalidate,
d_hash: hello_d_hash,
d_compare: hello_d_compare,*/
/*d_delete: hello_d_delete,*/
d_release: hello_d_release,
/*d_iput: hello_d_iput*/
};

/*创建超级块*/
struct super_block *hello_read_super(struct super_block *s, void *data,
      int silent)
{
printk("hello_read_super\n");
struct inode * root_inode;

s->;s_blocksize = 1024;
s->;s_blocksize_bits = 10;
s->;s_magic = 0;
s->;s_op = &hello_sops;
root_inode = hello_get_inode(s, HELLO_ROOT_INO, &hello_root);
if (!root_inode)
goto out_no_root;

s->;s_root = d_alloc_root(root_inode);
if (!s->;s_root)
goto out_no_root;
s->;s_root->;d_op = &hello_dops;
return s;

out_no_root:
printk("hello_read_super: get root inode failed\n");
iput(root_inode);
return NULL;
} hello.h

CODE:

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#include <linux/kernel.h>;
#include <linux/module.h>;

#include <linux/fs.h>;
#include <linux/wrapper.h>;
#include <linux/slab.h>;
#include <linux/wait.h>;
#include <linux/poll.h>;

#include <linux/mm.h>;
#include <linux/pagemap.h>;

#include <asm/uaccess.h>;
#include <asm/semaphore.h>;

#define HELLO_ROOT_INO 1

typedef int (read_hello_t)(char *page, char **start, off_t off,
int count, int *eof, void *data);
typedef int (write_hello_t)(struct file *file, const char *buffer,
unsigned long count, void *data);
typedef int (get_info_t)(char *, char **, off_t, int);

struct hello_dir_entry {
unsigned short low_ino;
unsigned short namelen;
const char *name;
mode_t mode;
nlink_t nlink;
uid_t uid;
gid_t gid;
unsigned long size;
struct inode_operations * hello_iops;
struct file_operations * hello_fops;
get_info_t *get_info;
struct module *owner;
struct hello_dir_entry *next, *parent, *subdir;
void *data;
read_hello_t *read_hello;
write_hello_t *write_hello;
atomic_t count; /* use count */
int deleted; /* delete flag */
kdev_t rdev;
};

extern struct hello_dir_entry hello_root;
extern struct dentry *hello_lookup(struct inode *, struct dentry *);
extern int hello_misc_init(void);
extern struct super_block *hello_read_super(struct super_block *, void *, int);
extern void de_put(struct hello_dir_entry *);
extern struct hello_dir_entry * de_get(struct hello_dir_entry *);
extern int hello_readdir(struct file *, void *, filldir_t); /*这个文件的作用是创建虚拟文件树结构，相当于磁盘上的文件树，这里我就不注释了，有兴趣的自己看看吧，挺简单的*/
hello_entry.c

CODE:

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#include "hello.h"

static struct inode_operations hello_dir_inode_operations = {
lookup: hello_lookup,
};

struct hello_dir_entry * de_get(struct hello_dir_entry *de)
{
printk("de_get\n");
if (de)
atomic_inc(&de->;count);
return de;
}

void inline free_hello_entry(struct hello_dir_entry *de)
{
printk("free_hello_entry\n");
kfree(de);
}

void de_put(struct hello_dir_entry *de)
{
printk("de_put\n");
if (de) {
if (!atomic_read(&de->;count)) {
printk("de_put: entry %s already free!\n", de->;name);
return;
}

if (atomic_dec_and_test(&de->;count))
free_hello_entry(de);
}
}

static ssize_t
hello_file_read(struct file * file, char * buf, size_t nbytes, loff_t *ppos)
{
struct inode * inode = file->;f_dentry->;d_inode;
char *page;
ssize_t n;
char *start;
struct hello_dir_entry * dp;

dp = (struct hello_dir_entry *) inode->;u.generic_ip;
if (!(page = (char*) __get_free_page(GFP_KERNEL)))
return -ENOMEM;

n = dp->;read_hello(page, &start, *ppos,0,  NULL, NULL);
copy_to_user(buf, page, n);

free_page((unsigned long) page);
return n;
}

static ssize_t
hello_file_write(struct file * file, const char * buffer,
size_t count, loff_t *ppos)
{
struct inode *inode = file->;f_dentry->;d_inode;
struct hello_dir_entry * dp;

dp = (struct hello_dir_entry *) inode->;u.generic_ip;

if (!dp->;write_hello)
return -EIO;

/* FIXME: does this routine need ppos?  probably... */
return dp->;write_hello(file, buffer, count, dp->;data);
}

static loff_t
hello_file_lseek(struct file * file, loff_t offset, int origin)
{
long long retval;

switch (origin) {
case 2:
offset += file->;f_dentry->;d_inode->;i_size;
break;
case 1:
offset += file->;f_pos;
}
retval = -EINVAL;
if (offset>;=0 && offset<=file->;f_dentry->;d_inode->;i_sb->;s_maxbytes) {
if (offset != file->;f_pos) {
file->;f_pos = offset;
file->;f_reada = 0;
}
retval = offset;
}
return retval;
}

static struct file_operations hello_file_operations = {
llseek: hello_file_lseek,
read: hello_file_read,
write: hello_file_write,
};

static int hello_register(struct hello_dir_entry * dir, struct hello_dir_entry * dp)
{
printk("hello_register\n");
dp->;low_ino = 2;
dp->;next = dir->;subdir;
dp->;parent = dir;
dir->;subdir = dp;
if (S_ISDIR(dp->;mode)) {
if (dp->;hello_iops == NULL) {
dp->;hello_fops = NULL;
dp->;hello_iops = &hello_dir_inode_operations;
}
dir->;nlink++;
} else if (S_ISREG(dp->;mode)) {
if (dp->;hello_fops == NULL)
dp->;hello_fops = &hello_file_operations;
}

return 0;
}

static struct hello_dir_entry *hello_create(struct hello_dir_entry **parent,
   const char *name,
   mode_t mode,
   nlink_t nlink)
{
printk("hello_create\n");
struct hello_dir_entry *ent = NULL;
const char *fn = name;
int len;

len = strlen(name);
*parent = &hello_root;

ent = kmalloc(sizeof(struct hello_dir_entry) + len + 1, GFP_KERNEL);
if (!ent) goto out;

memset(ent, 0, sizeof(struct hello_dir_entry));
memcpy(((char *) ent) + sizeof(struct hello_dir_entry), fn, len + 1);
ent->;name = ((char *) ent) + sizeof(*ent);
ent->;namelen = len;
ent->;mode = mode;
ent->;nlink = nlink;
out:
return ent;
}

struct hello_dir_entry *create_hello_entry(const char *name, mode_t mode,
   struct hello_dir_entry *parent)
{
printk("create_hello_entry\n");
struct hello_dir_entry *ent;
nlink_t nlink;

if (S_ISDIR(mode)) {
if ((mode & S_IALLUGO) == 0)
mode |= S_IRUGO | S_IXUGO;
nlink = 2;
} else {
if ((mode & S_IFMT) == 0)
mode |= S_IFREG;
if ((mode & S_IALLUGO) == 0)
mode |= S_IRUGO;
nlink = 1;
}

ent = hello_create(&parent,name,mode,nlink);
if (ent) {
if (hello_register(parent, ent) < 0) {
kfree(ent);
ent = NULL;
}
}
return ent;
}

static inline struct hello_dir_entry *hello_read_entry(const char *name,
mode_t mode, struct hello_dir_entry *base,
read_hello_t *read_hello, void * data)
{
printk("hello_dir_entry\n");
struct hello_dir_entry *res=create_hello_entry(name,mode,base);
if (res) {
res->;read_hello=read_hello;
res->;write_hello = NULL;
res->;data=data;
}
return res;
}

/************************************************************************************************************/
int read_hello(char *page, char **start, off_t off, int count, int *eof, void *data)
{
strcpy(page, "hello world!");
return 13;
}

int hello_misc_init(void)
{
printk("hello_misc_init\n");
struct hello_dir_entry *err;
err = hello_read_entry("zhang", 0, NULL, read_hello, NULL);
return !err;
} mount.c

CODE:

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#include "hello.h"
/*加载模块并安装文件系统*/

static DECLARE_FSTYPE(hello_fs_type, "hello", hello_read_super, FS_SINGLE);
struct vfsmount *mnt;

int hello_root_init(void)
{
struct nameidata nd;
int err;
err = register_filesystem(&hello_fs_type);
printk("register_filesystem\n");
if (err)
return err;
mnt = kern_mount(&hello_fs_type);/*安装文件系统*/
printk("kern_mount\n");
err = PTR_ERR(mnt);
if (IS_ERR(mnt))
goto out;
hello_misc_init();

MOD_DEC_USE_COUNT;
char *name, *type;
name = kmalloc(10, GFP_KERNEL);
type = kmalloc(10, GFP_KERNEL);
strcpy(name, "/hello");
strcpy(type, "hello");
long (*do_mount)(char *, char *, char *, unsigned long, void *) = (void*)0xc01603f0;/*0xc0166ad0;*/
do_mount(NULL, name, type, 0, NULL);
kfree(name);
kfree(type);
/*if (err)
goto out;
*/

return 0;
out:
mntput(mnt);
unregister_filesystem(&hello_fs_type);
return err;
}

int init_module(void)
{
printk("init_module\n");
hello_root_init();
return 0;
}

void cleanup_module()
{
printk("cleanup_module\n");
mntput(mnt);
unregister_filesystem(&hello_fs_type);
} Makefile

CODE:

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CC = gcc
CFLAGS = -O -Wall -D__KERNEL__ -DMODULE
#INCLUDEDIR = /usr/local/linux-2.4.22/include

INCLUDEDIR = /usr/src/linux-2.4.20-8/include
CFLAGS += -I$(INCLUDEDIR)

myfs.o: mount.o hello_entry.o hello.o
$(LD) -m elf_i386 -r -o myfs.o mount.o hello_entry.o hello.o

mount.o: mount.c hello.h /usr/include/linux/version.h
$(CC) $(CFLAGS) -c mount.c

hello_entry.o: hello_entry.c hello.h /usr/include/linux/version.h
$(CC) $(CFLAGS) -c hello_entry.c

hello.o: hello.c hello.h /usr/include/linux/version.h
$(CC) $(CFLAGS) -c hello.c 测试程序read.c

CODE:

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#include <sys/ioctl.h>;
#include <sys/types.h>;
#include <sys/stat.h>;
#include <fcntl.h>;

int main()
{
int fp;
char buf[11];
buf[10] = 0;
int i;

if ((fp = open("/hello/zhang", O_RDWR)) == 0) {
printf("Could not opened!\n");
return -1;
}
else
printf("File open ok!\n");
read(fp, buf, 13);
printf("%s\n", buf);
close(fp);
}