简单的ioctl操作

mem___test.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 


#include "memdev.h"




struct mem_dev *mem_devp; /*设备结构体指针*/


struct cdev cdev;


/*文件打开函数*/
int mem_open(struct inode *inode, struct file *filp)
{
printk(KERN_ERR "here into open\n");
        return 0;
}


int mem_release(struct inode *inode, struct file *filp)
{
        return 0;
}


/*IO操作*/
int memtest_ioctl(struct inode *inode, unsigned int cmd, unsigned long arg)
{


        int err = 0;
        int ret = 0;
        int ioarg = 0;


        switch(cmd)
        {


        case MEMDEV_IOCPRINT:
                printk("<--- CMD memtest_IOCPRINT Done--->\n\n");
                break;




        case MEMDEV_IOCSETDATA:
                ret = __get_user(ioarg, (int *)arg);
                printk("<--- In Kernel memtest_IOCSETDATA ioarg = %d --->\n\n",ioarg);
                break;


case MEMDEV_IOTEST:
printk(KERN_ERR "into ioctl kernel data test\n");
struct test_data *test = (struct test_data *)arg;
if(test == NULL || test->data == NULL || test->change == NULL)
{
return 0;
printk(KERN_ERR "test is null");
}


struct st m_st;
int a = 200;
printk("%s \t %s\n",test->data,test->change);
printk("current data len %d",test->data_len);
char *ddd = "hello world!!!!!!!!!!!";
memcpy(m_st.st_data,ddd,strlen(ddd));
m_st.st_len = 50;
copy_to_user(test->data,ddd,strlen(ddd));
copy_to_user(test->change,ddd,strlen(ddd));
copy_to_user(test->st,&m_st,sizeof(struct st));
copy_to_user(&(test->data_len),&a,sizeof(int));
break;
        default:
                return -EINVAL;
        }
        return ret;
}


/*文件操作结构体*/
static const struct file_operations mem_fops =
{
        .owner = THIS_MODULE,
        .open = mem_open,
        .release = mem_release,
        .unlocked_ioctl = memtest_ioctl,
};


static struct class *my_class;
struct device *dev;
static int major;
static int memtest_init(void)
{
major = register_chrdev(0, "mem_test",&mem_fops);
my_class = class_create(THIS_MODULE, "mem_test"); 
device_create(my_class, NULL, MKDEV(major, 4), NULL, "%s", "mem_test");
return 0;
}


static void memtest_exit(void)
{
device_destroy(my_class,MKDEV(major,4));
class_destroy(my_class);
unregister_chrdev(major, "mem_test");
return;
}


MODULE_AUTHOR("David Xie");
MODULE_LICENSE("GPL");


module_init(memtest_init);
module_exit(memtest_exit);

app.c

#include 
#include
#include
#include
#include
#include 


#include "memdev.h"  /* 包含命令定义 */


int main()
{
        int fd = 0;
        int cmd;
        int arg = 0;
        char Buf[4096];




        /*打开设备文件*/
        fd = open("/dev/mem_test",O_RDWR);
        if (fd < 0)
        {
                printf("Open Dev Mem0 Error!\n");
                return -1;
        }


struct test_data test;


const char a_data[1024] = {'z','z','z','z','z','z','z','z',0};
const char p_data[1024] = {'z','z','z','z','z','z','z','z',0};
const char *hhh = a_data;
test.data = p_data;
test.change= hhh;
test.st = malloc(1024);
test.data_len = 100;


printf("before ioctl test data\n");
printf("before %s\n",test.change);
printf("before %s\n",test.data);
printf("before int %d",test.data_len);
int ret = ioctl(fd,MEMDEV_IOTEST,&test);
printf("ioctl ret %d\n",ret);
printf("after ioctl test data\n");
printf("after %s\n",test.change);
printf("after %s\n",test.data);
printf("after int %d\n",test.data_len);
printf("after %s\n",((struct st *)(test.st))->st_data);
printf("after %d\n",((struct st *)(test.st))->st_len);




        close(fd);
        return 0;
}

memdev.h

#ifndef _MEMDEV_H_
#define _MEMDEV_H_


#include 


#ifndef MEMDEV_MAJOR
#define MEMDEV_MAJOR 0   /*预设的mem的主设备号*/
#endif


#ifndef MEMDEV_NR_DEVS
#define MEMDEV_NR_DEVS 2    /*设备数*/
#endif


#ifndef MEMDEV_SIZE
#define MEMDEV_SIZE 4096
#endif
/*mem设备描述结构体*/
struct mem_dev                                     
{                                                        
  char *data;                      
  unsigned long size;       
};




struct st
{
char st_data[100];
int st_len;
};




struct test_data
{
void *st;
void *data;
int data_len;
char *change;
};


/* 定义幻数 */
#define MEMDEV_IOC_MAGIC  'k'


/* 定义命令 */
#define MEMDEV_IOCPRINT   _IO(MEMDEV_IOC_MAGIC, 1)
#define MEMDEV_IOCGETDATA _IOR(MEMDEV_IOC_MAGIC, 2, int)
#define MEMDEV_IOCSETDATA _IOW(MEMDEV_IOC_MAGIC, 3, int)
#define MEMDEV_IOTEST _IOWR(MEMDEV_IOC_MAGIC, 4, int)


#endif

makefile

obj-m := mem___test.o

KDIR := /lib/modules/$(shell uname -r)/build

PWD := $(shell pwd)

default:
    $(MAKE) -C $(KDIR) M=$(PWD) modules

clean:
    rm -rf .*.cmd *.o *.mod.c *.ko .tmp_versions *.order *symvers *Module.markers