《Linux设备驱动程序》第三版 scull编译 Ubuntu18.04

时间:2021-12-25 22:27:02

0 准备工作。

0.0 系统环境:Ubuntu18.04.1 amd64。

0.1 安装必要软件包

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sudo  apt  install  build-essential bison flex libssl-dev libelf-dev

  

1 下载内核源码,构建源码树

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sudo  apt  install  linux- source -4.15.0 -y
 
cd  /usr/src/linux-source-4 .15.0/
sudo  tar  xf linux- source -4.15.0. tar .bz2
 
cd  linux- source -4.15.0/
 
sudo  make  oldconfig
 
sudo  make  prepare
 
sudo  make  scripts

  

2 编译驱动源码

源码需要改动几处:

copy_to_user()改为raw_copy_to_user();

copy_from_user()改为raw_copy_from_user();

init_MUTEX((&scull_device->sem);改为sema_init(&scull_device->sem, 1);

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make
 
sudo  insmod scull.ko
 
sudo  rmmod scull.ko

 

 

附1:scull.c

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#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
 
#include "scull.h"
 
int  scull_major = SCULL_MAJOR;
int  scull_minor = 0;
 
module_param(scull_major,  int , S_IRUGO);
module_param(scull_minor,  int , S_IRUGO);
 
struct  scull_dev *scull_device;
 
int  scull_trim( struct  scull_dev *dev)
{
     if  (dev)
     {
         if  (dev->data)
         {
             kfree(dev->data);
         }
         dev->data = NULL;
         dev->size = 0;
     }
     return  0;
}
 
int  scull_open( struct  inode *inode,  struct  file *filp)
{
     struct  scull_dev *dev;
 
     dev = container_of(inode->i_cdev,  struct  scull_dev, cdev);
     filp->private_data = dev;
 
     if  ((filp->f_flags & O_ACCMODE) == O_WRONLY)
     {
         if  (down_interruptible(&dev->sem))
         {
             return  -ERESTARTSYS;
         }
         scull_trim(dev);
         up(&dev->sem);
     }
 
     return  0;
}
 
int  scull_release( struct  inode *inode,  struct  file *filp)
{
     return  0;
}
 
ssize_t scull_read( struct  file *filp,  char  __user *buf,  size_t  count, loff_t *f_pos)
{
     struct  scull_dev *dev = filp->private_data;
     ssize_t retval = 0;
 
     if  (down_interruptible(&dev->sem))
     {
         return  -ERESTARTSYS;
     }
     if  (*f_pos >= dev->size)
     {
         goto  out;
     }
     if  (*f_pos + count > dev->size)
     {
         count = dev->size - *f_pos;
     }
 
     if  (!dev->data)
     {
         goto  out;
     }
 
     if  (raw_copy_to_user(buf, dev->data + *f_pos, count))
     {
         retval = -EFAULT;
         goto  out;
     }
 
     *f_pos += count;
     retval = count;
 
     out:
         up(&dev->sem);
         return  retval;
}
 
ssize_t scull_write( struct  file *filp,  const  char  __user *buf,  size_t  count, loff_t *f_pos)
{
     struct  scull_dev *dev = filp->private_data;
     ssize_t retval = -ENOMEM;
 
     if  (down_interruptible(&dev->sem))   
     {
         return  -ERESTARTSYS;
     }
 
     if  (!dev->data)   
     {
         dev->data = kmalloc(SCULL_BUFFER_SIZE, GFP_KERNEL);
         if  (!dev->data)
         {
             goto  out;
         }
         memset (dev->data, 0, SCULL_BUFFER_SIZE);
      }
 
     if  (count > SCULL_BUFFER_SIZE - dev->size)
     {
         count = SCULL_BUFFER_SIZE - dev->size;
     }
 
     if  (raw_copy_from_user(dev->data + dev->size, buf, count))
     {
         retval = -EFAULT;
         goto  out;
     }
     
     dev->size += count;
     retval = count;
 
     out:
         up(&dev->sem);
         return  retval;
}
 
loff_t scull_llseek( struct  file *filp, loff_t off,  int  whence)
{
     struct  scull_dev *dev = filp->private_data;
     loff_t newpos;
 
     switch (whence)
     {
         case  0:
             newpos = off;
             break ;
         case  1:
             newpos = filp->f_pos + off;
             break ;
         case  2:
             newpos = dev->size + off;
             break ;
         default :
             return  -EINVAL;
     }
     if  (newpos < 0)
     {
         return  -EINVAL;
     }
     filp->f_pos = newpos;
     return  newpos;
}
 
struct  file_operations scull_fops = {
     .owner = THIS_MODULE,
     .llseek = scull_llseek,
     .read = scull_read,
     .write = scull_write,
     .open = scull_open,
     .release = scull_release,   
};
 
void   scull_cleanup_module( void )
{
     dev_t devno = MKDEV(scull_major, scull_minor);
 
     if  (scull_device)
     {
         scull_trim(scull_device);
         cdev_del(&scull_device->cdev);
         kfree(scull_device);   
     }
     unregister_chrdev_region(devno, 1);
}
 
static  void  scull_setup_cdev( struct  scull_dev *dev)
{
     int  err, devno = MKDEV(scull_major, scull_minor);
 
     cdev_init(&dev->cdev, &scull_fops);
     dev->cdev.owner = THIS_MODULE;
     dev->cdev.ops = &scull_fops;
     err = cdev_add(&dev->cdev, devno, 1);
 
     if  (err)
     {
         printk(KERN_NOTICE  "Error %d adding scull" , err);
     }
}
 
static  int  __init scull_init_module( void )
{
     int  result;
     dev_t dev = 0;
 
     if  (scull_major)   
     {
         dev = MKDEV(scull_major, scull_minor);
         result = register_chrdev_region(dev, 1,  "scull" );
     }
     else
     {
         result = alloc_chrdev_region(&dev, scull_minor, 1,  "scull" );
         scull_major = MAJOR(dev);
     }
     if  (result < 0)
     {
         printk(KERN_WARNING  "scull: can't get major %d\n" , scull_major);
         return  result;
     }
 
     scull_device = kmalloc( sizeof ( struct  scull_dev), GFP_KERNEL);       
     if  (!scull_device)
     {
         result = -ENOMEM;
         goto  fail;
     }
     memset (scull_device, 0,  sizeof ( struct  scull_dev));
 
     sema_init(&scull_device->sem, 1);
 
     scull_setup_cdev(scull_device);
 
     return  0;
 
     fail:
         scull_cleanup_module();
         return  result;
}
 
module_init(scull_init_module);
module_exit(scull_cleanup_module);
 
MODULE_LICENSE( "GPL" );

  

附2:scull.h

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#ifndef _SCULL_H
#define _SCULL_H
 
#define SCULL_MAJOR 0
#define SCULL_BUFFER_SIZE PAGE_SIZE
 
struct  scull_dev {
     char  *data;
     unsigned  long  size;
     struct  semaphore sem;
     struct  cdev cdev;
};
 
#endif

  

附3:Makefile

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#sample driver module
obj-m := scull.o
KDIR =  /root/linux-2 .6.36.4/
PWD:=$(shell  pwd )
INSTALLDIR=$(PWD)
modules:
     $(MAKE) -C  /lib/modules/ ` uname  -r` /build  M=` pwd ` modules
clean:
     rm  -f *.mod.c *.mod.o *.ko *.o *.tmp_versions
.PHONY:modules clean