Linux 创建文件的应用和驱动代码

A：

Linux创建文件的应用代码：

#include <stdio.h>
#include <stdlib.h>

int main()
{
   FILE *fp;
   char str[] = "This is a file created by Linux.";
   
   fp = fopen( "file.txt" , "w" );
   fwrite(str , 1 , sizeof(str) , fp );
   
   fclose(fp);
   return 0;
}

该程序会在当前路径下创建一个名为“file.txt”的文件，并向其中写入字符串“This is a file created by Linux.”

Linux创建文件的驱动代码：

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

MODULE_LICENSE("GPL"); 

static int my_open(struct inode *inode, struct file *file)
{
    printk(KERN_INFO "mychardevice : open()\n");
    return 0;
}

static ssize_t my_read(struct file *file, char *buf, size_t count, loff_t *pos)
{
    printk(KERN_INFO "mychardevice : read()\n");
    return 0;
}

static ssize_t my_write(struct file *file, const char *buf, size_t count, loff_t *pos)
{
    printk(KERN_INFO "mychardevice : write()\n");
    return 0;
}

static int my_close(struct inode *inode, struct file *file)
{
    printk(KERN_INFO "mychardevice : release()\n");
    return 0;
}

static struct file_operations my_fops =
{
    .owner = THIS_MODULE,
    .open = my_open,
    .release = my_close,
    .read = my_read,
    .write = my_write,
};

static int __init mychardevice_init(void)
{
    printk(KERN_INFO "mychardevice : init()\n");
    register_chrdev(0, "mychardevice", &my_fops);
    return 0;
}

static void __exit mychardevice_exit(void)
{
    printk(KERN_INFO "mychardevice : exit()\n");
    unregister_chrdev(0, "mychardevice");
}

module_init(mychardevice_init);
module_exit(mychardevice_exit);

该驱动代码会注册一个名为“mychardevice”的字符设备，并提供设备文件的打开、读、写、关闭等接口。通过系统调用可以使用这些接口来创建文件或向文件中写入数据。