Linux内核中读写文件数据的方法

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/syscalls.h>
#include <asm/unistd.h>
#include <asm/uaccess.h>

#define MY_FILE "/root/LogFile"

char buf[128];
struct file *file = NULL;

static int __init init(void)
{
mm_segment_t old_fs;
printk("Hello, I'm the module that intends to write messages to file.\n");

if(file == NULL)
file = filp_open(MY_FILE, O_RDWR | O_APPEND | O_CREAT, 0644);
if (IS_ERR(file)) {
printk("error occured while opening file %s, exiting...\n", MY_FILE);
return 0;
}

sprintf(buf,"%s", "The Messages.");

old_fs = get_fs();
set_fs(KERNEL_DS);
file->f_op->write(file, (char *)buf, sizeof(buf), &file->f_pos);
set_fs(old_fs);
filp_close(file, NULL);
file = NULL;
return 0;
}

static void __exit fini(void)
{
if(file != NULL)
filp_close(file, NULL);
}

module_init(init);
module_exit(fini);
MODULE_LICENSE("GPL");