新手问题请教__struct_include_int_test_driver_filp_

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新手问题请教

来源: 互联网发布时间：2016-08-23

本文导语: 在linux内核加栽下面的模块: #include #include #include #include #include #include #include #include #define PINFO(fmt,args...) printk(KERN_INFO "[%s]" fmt,__FUNCTION__ ##args) #define SIZE 100 int major=0; int minor=0; unsigned int devno; struct...

在linux内核加栽下面的模块:
#include
#include
#include
#include
#include
#include
#include
#include

#define PINFO(fmt,args...) printk(KERN_INFO "[%s]" fmt,__FUNCTION__ ##args)

#define SIZE 100
int major=0;
int minor=0;

unsigned int devno;

struct test_driver{
     char buf[SIZE];
     int irq;
     struct cdev my_cdev;
     int cur_size;
     struct fasync_struct *fa;
};
struct test_driver  mdr;
int test_fasync(int fd, struct file *flip, int on);

int test_open (struct inode *inod, struct file *filp)
{
     printk("init test drivern");
     struct test_driver *md=container_of(inod->i_cdev,struct test_driver,my_cdev);
     filp->private_data=md;
     return 0;
}
int test_close(struct inode *inod, struct file *filp)
{
     printk("close test drivern");
     filp->f_pos=0;
     test_fasync(-1, filp, 0);
     return 0;
}
ssize_t test_read (struct file *filp, char __user *buf, size_t count, loff_t *offset)
{
     struct test_driver *md=filp->private_data;
     int remain,ret;
    remain=copy_to_user(buf,md->buf+filp->f_pos,count);
    ret=count-remain;
    md->cur_size-=ret;

     return ret;
}
ssize_t test_write (struct file *filp, const char __user *buf, size_t count, loff_t *offset)
{
    struct test_driver *md=filp->private_data;
    int remain,ret;
    remain=copy_from_user(md->buf+filp->f_pos,buf,count);
    ret=count-remain;
    md->cur_size+=ret;
    kill_fasync(&md->fa,SIGIO,POLL_IN);
    return ret;
}
int test_fasync(int fd, struct file *flip, int on)
{
    struct test_driver *md=flip->private_data;
    return fasync_helper(fd,flip,on,&md->fa);

}

struct file_operations f_ops=
{
.open=test_open,
.release=test_close,
.read=test_read,
.write=test_write,
.fasync=test_fasync,
};
int init_test(void)
{
     if(major){
       devno=MKDEV(major,minor);
       register_chrdev_region(devno,1,"new test driver");
   }
   else{
       alloc_chrdev_region(&devno,0,1,"alloc devno");
       major=MAJOR(devno);
       minor=MINOR(devno);
       printk("major is %d,minor is %dn",major,minor);
   }

    cdev_init(&mdr.my_cdev,&f_ops);
    cdev_add(&mdr.my_cdev,devno,1);
    PINFO("init test drivern");
    return 0;
}

void exit_test(void)
{
    cdev_del(&mdr.my_cdev);
    unregister_chrdev_region(devno,1);
    PINFO("exit test drivern");
}

module_init(init_test);
module_exit(exit_test);

然后让这个应用程序在后台运行:
#include
#include
#include
#include
#include
#include
int fd;
char buf[20]={0};
static int flag=0;

void handler(int num)
{
   if(num==SIGIO)
     {
      int ret;
      ret=read(fd,buf,5);
      printf("app read,%d,%sn",ret,buf);
      flag=1;
      return;
     }
}

int main(void)
{
    struct sigaction sa;
    fd=open("/dev/test",O_RDWR);
    if(fd