Proc文件系统

#include <linux/proc_fs.h>static struct proc_dir_entry *proc_xxx = NULL;int xxx_read_proc(char *page, char **start, off_t off,int count, int *eof, void *data){    int len = 0;    if(off > 0)    {        *eof = 1;        return 0;    }    len = sprintf(page + len,"Debug  Mode: echo 1 >/proc/driver/xxx \n");    len += sprintf(page + len,"Normal Mode: echo 0 >/proc/driver/xxx \n");    return len;}static int xxx_write_proc(struct file *file, const char __user *buffer, unsigned long count, void *data){    char CommandLine[20] = {0};    if (0 != copy_from_user(CommandLine, buffer, 20))    {        printk("copy_from_user failed\r\n");        return -1;    }    sscanf(CommandLine, "%x", &DebugFlag);    return count;}static int __init xxx_init(void){    proc_xxx = create_proc_entry(MODULE_NAME, 0644,proc_root_driver);    if(proc_xxx != NULL)    {        proc_xxx->owner = THIS_MODULE;        proc_xxx->read_proc = xxx_read_proc;        proc_xxx->write_proc = xxx_write_proc;    }    else    {        printk("create_proc_entry for xxx failed!\n");        goto unregister_chrdev;    }    return 0;}static void __exit xxx_exit(void){    remove_proc_entry(MODULE_NAME,proc_root_driver);}module_init(xxx_init);module_exit(xxx_exit);