linux_dev_学习笔记_proc文件系统

2012年3月25日  Sunday

 

1、内核版本号2.6.33.20

 

2、proc文件系统简单示例

 

3、驱动模块源文件proc_dev.c

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

#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/fcntl.h>

#include <asm/uaccess.h>
#include <asm/io.h>

#include <linux/stat.h>
#include <linux/proc_fs.h>

struct proc_dir_entry *sumproc_root_fp =NULL;
struct proc_dir_entry *sumproc_val1_fp =NULL;
struct proc_dir_entry *sumproc_val2_fp =NULL;
struct proc_dir_entry *sumproc_result_fp =NULL;

char sumproc_str1[PAGE_SIZE-80]={0,};
char sumproc_str2[PAGE_SIZE-80]={0,};

int read_sumproc_val(char *page,char **start,
        off_t off,int count,
        int *eof,void *data_unused)
{
    char *buf;
    char *realdata;

    realdata=(char*)data_unused;
    buf=page;
    buf+=sprintf(buf,"Value=[%s]\n",realdata);

    *eof=1;
    return buf-page;
}

int write_sumproc_val(struct file *filp,const char __user *buffer,
        unsigned long count,void *data)
{
    int len;
    char *realdata;

    realdata=(char*)data;

    if(copy_from_user(realdata,buffer,count)){
        return -EFAULT;
    }

    realdata[count]='\0';
    len=strlen(realdata);
    if(realdata[len-1]=='\n'){
        realdata[--len]=0;
    }
    return count;
}

int read_sumproc_result(char *page,char **start,
        off_t off,int count,
        int *eof,void *data_unused)
{
    char *buf;
    int a,b,sum;
    buf=page;

    a=simple_strtoul(sumproc_str1,NULL,10);
    b=simple_strtoul(sumproc_str2,NULL,10);

    sum=a+b;
    buf+=sprintf(buf,"Result[%d+%d=%d]\n",a,b,sum);

    *eof=1;
    return buf-page;
}

int sumproc_init(void)
{
    sumproc_root_fp =proc_mkdir("sumproc",0);

    sumproc_val1_fp=create_proc_entry("val1",S_IFREG|S_IRWXU,sumproc_root_fp);

    if(sumproc_val1_fp){
        sumproc_val1_fp->data=sumproc_str1;
        sumproc_val1_fp->read_proc=read_sumproc_val;
        sumproc_val1_fp->write_proc=write_sumproc_val;
    }

    sumproc_val2_fp=create_proc_entry("val2",S_IFREG|S_IRWXU,sumproc_root_fp);

    if(sumproc_val2_fp){
        sumproc_val2_fp->data=sumproc_str2;
        sumproc_val2_fp->read_proc=read_sumproc_val;
        sumproc_val2_fp->write_proc=write_sumproc_val;
    }

    sumproc_result_fp=create_proc_entry("result",S_IFREG|S_IRWXU,sumproc_root_fp);

    if(sumproc_root_fp){
        sumproc_result_fp->read_proc=read_sumproc_result;
    }

    return 0;
}

void sumproc_exit(void)
{
    remove_proc_entry("result",sumproc_root_fp);
    remove_proc_entry("val1",sumproc_root_fp);
    remove_proc_entry("val2",sumproc_root_fp);
    remove_proc_entry("sumproc",0);
}

module_init(sumproc_init);
module_exit(sumproc_exit);

MODULE_LICENSE("Gual BSD/GPL");

4、Makefile

obj-m += proc_dev.o

CURRENT_PATH := $(shell pwd)

LINUX_KERNEL := $(shell uname -r)

LINUX_KERNEL_PATH := /usr/src/linux-$(LINUX_KERNEL)

all:
    make -C $(LINUX_KERNEL_PATH) M=$(CURRENT_PATH) modules
clean:
    #make -C $(LINUX_KERNEL_PAHT) M=$(CURRENT_PATH) clean
    rm *.mod.*
    rm *.order
    rm *.o
    rm *.symvers

5、执行方法及结果

~/proc_test# make //编译驱动模块
~/proc_test# make clean //清理不用到的生成文件
~/proc_test# insmod proc_dev.ko //插入驱动模块
~/proc_test# lsmod |grep proc_dev //查看驱动模块是否插入成功
proc_dev 9562 0
~/proc_test# echo "100" > /proc/sumproc/val1 //用echo向val1文件输入值
~/proc_test# cat /proc/sumproc/val1 //查看是否输入成功
Value=[100]
~/proc_test# echo "10" > /proc/sumproc/val2 //用echo向val2文件输入值
~/proc_test# cat /proc/sumproc/result //查看result文件中的运算结果
Result[100+10=110]

6、移除模块

~/proc_test# rmmod proc_dev //移除驱动模块