指定授權方式

沒有透過Module_LICENSE聚集指定授權方式的話，在載入驅動程式的時候就會顯示警告訊息，但不會拒絕載入程式。 訊息如下顯示:

Warning: loading xxxxxx.ko will taint the kernel: no license

很顯然這訊息是要您在 kernel module 裡面加上版權宣告，例如：”GPL”，”GPL v2″…等來宣告您的 module 並非 open source，利用 MODULE_LICENSE() 巨集來宣告程式 License，同樣的，可以用 MODULE_DESCRIPTION() 來描述此模組或者是 Driver 的功用跟簡介，以及用 MODULE_AUTHOR() 來定義此模組作者，這些巨集都可以在 linux/module.h 裡找到。

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

static int __init hello_init(void)
{
    pr_info("Hello, world appleboy\n");
    pr_info("The process is \"%s\" (pid %i)\n", current->comm, current->pid);
    return 0;
}

static void __exit hello_exit(void)
{
    printk(KERN_INFO "Goodbye\n");
}
MODULE_DESCRIPTION("Hello World !!");/* 此程式介紹與描述*/
MODULE_AUTHOR("Bo-Yi Wu <appleboy.tw at="" gmail.com="">");/* 此程式作者*/
MODULE_LICENSE("GPL");/* 程式 License*/
module_init(hello_init);
module_exit(hello_exit);

在 linux/module.h 裡頭，可以找到 MODULE_LICENSE 可定義的 License

 * software modules
 *
 *      "GPL"                           [GNU Public License v2 or later]
 *      "GPL v2"                        [GNU Public License v2]
 *      "GPL and additional rights"     [GNU Public License v2 rights and more]
 *      "Dual BSD/GPL"                  [GNU Public License v2
 *                                       or BSD license choice]
 *      "Dual MIT/GPL"                  [GNU Public License v2
 *                                       or MIT license choice]
 *      "Dual MPL/GPL"                  [GNU Public License v2
 *                                       or Mozilla license choice]
 *
 * The following other idents are available
 *
 *      "Proprietary"                   [Non free products]
 *
 * There are dual licensed components, but when running with Linux it is the
 * GPL that is relevant so this is a non issue. Similarly LGPL linked with GPL
 * is a GPL combined work.
 *
 * This exists for several reasons
 * 1.   So modinfo can show license info for users wanting to vet their setup 
 *      is free
 * 2.   So the community can ignore bug reports including proprietary modules
 * 3.   So vendors can do likewise based on their own policies
 */