菜鸟问题：隐式声明函数 copy_to_user。大家帮忙啊

wc9872

菜鸟问题：隐式声明函数 copy_to_user。大家帮忙啊 [复制链接]

#include
#include
#include        /* everything... */

#define DEVICE_NAME                "demo"
#define demo_MAJOR 249
#define demo_MINOR 0
#define MAX_BUF_LEN 20
static char drv_buf[20];


static int demo_open(struct inode *inode, struct file *file)        {
        //MOD_INC_USE_COUNT;
        sprintf(drv_buf,"device open sucess!\n");
        printk("device open sucess!\n");
        return 0;
}
static int  demo_release(struct inode *inode, struct file *filp)        {
        //MOD_DEC_USE_COUNT;
        printk("device release\n");
        return 0;
}


static ssize_t  demo_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)        {
        if(count > MAX_BUF_LEN)
                count=MAX_BUF_LEN;
        copy_to_user(buffer, drv_buf,count);
        printk("user read data from driver\n");
        return count;
}
static ssize_t  demo_write(struct file *filp,const char *buffer, size_t count)        {
        copy_from_user(drv_buf , buffer, count);
        printk("user write data to driver\n");
        //your code here
        return count;
}
static struct file_operations demo_fops = {
        write:        demo_write,       
        read:        demo_read,       
        open:        demo_open,
        release:        demo_release,
};

static int __init demo_init(void)        {
    int result;
    SET_MODULE_OWNER(&demo_fops);
    result = register_chrdev(demo_MAJOR, "demo", &demo_fops);
    if (result < 0) return result;
        printk(DEVICE_NAME " initialized\n");
        return 0;
}
static void __exit  demo_exit(void)        {
    unregister_chrdev(demo_MAJOR, "demo");
        printk(DEVICE_NAME " unloaded\n");
}
module_init(demo_init);
module_exit(demo_exit);


makefile

obj-m := demo.o
#KERNEL_DIR :=/lib/modules/$(shell uname -r)/build
KERNEL_DIR :=/lib/modules/2.6.18-1.2798.fc6/build
PWD := $(shell pwd)
default:
        $(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules

rm198

加了一段代码：

#include
#include
#include        /* everything... */

#define DEVICE_NAME                "demo"
#define demo_MAJOR 249
#define demo_MINOR 0
#define MAX_BUF_LEN 20
static char drv_buf[20];

unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
{
        if (access_ok(VERIFY_WRITE, to, n))
                n = __copy_to_user(to, from, n);
        return n;
}

unsigned long   copy_from_user(void *to, const void __user *from, unsigned long n)
{
        if (access_ok(VERIFY_READ, from, n))
                n = __copy_from_user(to, from, n);
        else
                memset(to, 0, n);
        return n;
}

static int demo_open(struct inode *inode, struct file *file)        {
        //MOD_INC_USE_COUNT;
        sprintf(drv_buf,"device open sucess!\n");
        printk("device open sucess!\n");
        return 0;
}
static int  demo_release(struct inode *inode, struct file *filp)        {
        //MOD_DEC_USE_COUNT;
        printk("device release\n");
        return 0;
}


static ssize_t  demo_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)        {
        if(count > MAX_BUF_LEN)
                count=MAX_BUF_LEN;
        copy_to_user(buffer, drv_buf,count);
        printk("user read data from driver\n");
        return count;
}
static ssize_t  demo_write(struct file *filp,const char *buffer, size_t count)        {
        copy_from_user(drv_buf , buffer, count);
        printk("user write data to driver\n");
        //your code here
        return count;
}
static struct file_operations demo_fops = {
        write:        demo_write,       
        read:        demo_read,       
        open:        demo_open,
        release:        demo_release,
};

static int __init demo_init(void)        {
    int result;
    SET_MODULE_OWNER(&demo_fops);
    result = register_chrdev(demo_MAJOR, "demo", &demo_fops);
    if (result < 0) return result;
        printk(DEVICE_NAME " initialized\n");
        return 0;
}
static void __exit  demo_exit(void)        {
    unregister_chrdev(demo_MAJOR, "demo");
        printk(DEVICE_NAME " unloaded\n");
}
module_init(demo_init);
module_exit(demo_exit);



make 还是过不去

[root@localhost ~]# cd /home/cc/demo
bash: cd: /home/cc/demo: 没有那个文件或目录
[root@localhost ~]# cd /home/cc/code/demo
[root@localhost demo]# ls
demo.c  demo.c~  Makefile  Makefile~  test_demo.c  test_demo.c~
[root@localhost demo]# make
make -C /lib/modules/2.6.18-1.2798.fc6/build M=/home/cc/code/demo modules
make[1]: Entering directory `/usr/src/kernels/2.6.18-1.2798.fc6-i586'
  CC [M]  /home/cc/code/demo/demo.o
/home/cc/code/demo/demo.c: 在函数 ‘copy_to_user’ 中：
/home/cc/code/demo/demo.c:13: 错误：隐式声明函数‘access_ok’
/home/cc/code/demo/demo.c:13: 错误：‘VERIFY_WRITE’ 未声明 (在此函数内第一次使用)
/home/cc/code/demo/demo.c:13: 错误：(即使在一个函数内多次出现，每个未声明的标识符在其
/home/cc/code/demo/demo.c:13: 错误：所在的函数内只报告一次。)
/home/cc/code/demo/demo.c:14: 错误：隐式声明函数 ‘__copy_to_user’
/home/cc/code/demo/demo.c: 在函数 ‘copy_from_user’ 中：
/home/cc/code/demo/demo.c:20: 错误：‘VERIFY_READ’ 未声明 (在此函数内第一次使用)
/home/cc/code/demo/demo.c:21: 错误：隐式声明函数 ‘__copy_from_user’
/home/cc/code/demo/demo.c: 在顶层：
/home/cc/code/demo/demo.c:54: 警告：从不兼容的指针类型初始化
/home/cc/code/demo/demo.c: 在函数 ‘demo_init’ 中：
/home/cc/code/demo/demo.c:62: 错误：隐式声明函数 ‘SET_MODULE_OWNER’
make[2]: *** [/home/cc/code/demo/demo.o] 错误 1
make[1]: *** [_module_/home/cc/code/demo] 错误 2
make[1]: Leaving directory `/usr/src/kernels/2.6.18-1.2798.fc6-i586'
make: *** [default] 错误 2
[root@localhost demo]#

melody0219

不必在代码中实现 copy_to_user 和 copy_from_user，系统核心已经实现了。如果需要这个，只需要包含

[code]

zxcc

copy_from_user()和copy_to_user()函数的作用：由于内核空间与用户空间的内存不能直接互访，因此借助
函数copy_to_user()完成用户空间到内核空间的复制，函数copy_from_user()完成内核空间到用户空间的复制。

1. //源码：linux/arch/i386/lib/usercopy.c
   
2. 
   
3. copy_to_user: - Copy a block of data into user space.
   
4. @to:   Destination address, in user space.
   
5. @from: Source address, in kernel space.
   
6. @n:    Number of bytes to copy.
   
7. 849unsigned long    copy_to_user(void __user *to, const void *from, unsigned long n)
   
8. 
   
9. 850{
   
10. 
    
11. 851        if (access_ok(VERIFY_WRITE, to, n))
    
12. 852                n = __copy_to_user(to, from, n);
    
13. 853        return n;
    
14. 854}
    
15. 
    
16. copy_from_user: - Copy a block of data from user space.
    
17. @to:   Destination address, in kernel space.
    
18. @from: Source address, in user space.
    
19. @n:    Number of bytes to copy.
    
20. 
    
21. 874unsigned long   copy_from_user(void *to, const void __user *from, unsigned long n)
    
22. 875{
    
23. 876        if (access_ok(VERIFY_READ, from, n))
    
24. 877                n = __copy_from_user(to, from, n);
    
25. 878        else
    
26. 879                memset(to, 0, n);
    
27. 880        return n;
    
28. 881}
    

复制代码

wensonxu

哥们，我还是不知道错在哪儿？

yueivwdt

你要问什么？

你就贴了一个

1. 
   
2. 菜鸟问题：隐式声明函数 copy_to_user。大家帮忙啊
   

复制代码

加一段代码啦....

wicom2010

使用copy_to_user()和copy_from_user()需包含头文件