如何编译linux第一个模块 hello.c

如何编译linux第一个模块 hello.c

转自：http://blog.csdn.net/sabalol/article/details/2076610

分类： kernel 2008-02-01 11:38 16161人阅读 评论(27)收藏 举报

linuxdependenciesmakefilemoduledocumentationsecurity

看了书后，照着书上的方法一步一步去做，却失败了，555
真是的，写书的人啊，却不考虑一下细节问题
新建一个目录
[liu@liu-desktop hellomod]$mddir hellomod
[liu@liu-desktop hellomod]$cd hellomod
[liu@liu-desktop hellomod]$vi hellomod.c

/****************hellomod.c*******************************/
#include <linux/module.h> //所有模块都需要的头文件
#include <linux/init.h> // init&exit相关宏
MODULE_LICENSE("GPL");
static int __init hello_init (void)
{
printk("Hello china init/n");
return 0;
}

static void __exit hello_exit (void)
{
printk("Hello china exit/n");
}

module_init(hello_init);
module_exit(hello_exit);

/****************hellomod.c*******************************/


1、在www.kernel.org下载了linux 2.6的内核，解压到/usr/src/linux26目录下
[root@liu-desktop linux26]# ls
arch CREDITS drivers init kernel Makefile README security
block crypto fs ipc lib mm REPORTING-BUGS sound
COPYING Documentation include Kbuild MAINTAINERS netscripts usr
----------------------------------------------
写一个Makefile文件：
内容如下：
obj-m := hellomod.o
------------------------------------------------
[liu@liu-desktop hellomod]$ make -C /usr/src/linux26/ SUBDIRS=$PWD modules
make: Entering directory `/usr/src/linux26'

ERROR: Kernel configuration is invalid.
include/linux/autoconf.h or include/config/auto.conf are missing.
Run 'make oldconfig && make prepare' on kernel src to fix it.


WARNING: Symbol version dump /usr/src/linux26/Module.symvers
is missing; modules will have no dependencies and modversions.

CC [M] /home/liu/test/hellomod/hellomod.o
cc1: 错误： include/linux/autoconf.h：No such file or directory
在包含自 include/linux/posix_types.h：47 的文件中，
从 include/linux/types.h：14，
从 include/linux/prefetch.h：13，
从 include/linux/list.h：8，
从 include/linux/module.h：9，
从 /home/liu/test/hellomod/hellomod.c：1:
/usr/lib/gcc/i486-linux-gnu/4.1.3/include/asm/posix_types.h:13:22: 错误： features.h：No such file or directory
/usr/lib/gcc/i486-linux-gnu/4.1.3/include/asm/posix_types.h:14:35: 错误： 没有包含路径可供搜索 asm/posix_types.h
...............................


解决方法：

[liu@liu-desktop hellomod]#make oldconfig
[liu@liu-desktop hellomod]#make prepare


好了，在试试：
[liu@liu-desktop hellomod]$ make -C /usr/src/linux26/ SUBDIRS=$PWD modules
还是有错：
make: Entering directory `/usr/src/linux26'

WARNING: Symbol version dump /usr/src/linux26/Module.symvers
is missing; modules will have no dependencies and modversions.

CC [M] /home/liu/test/hellomod/hellomod.o
Building modules, stage 2.
MODPOST 1 modules
/bin/sh: scripts/mod/modpost: not found
make[1]: *** [__modpost] 错误 127
make: *** [modules] 错误 2
make: Leaving directory `/usr/src/linux26'


看到了吗，提示说没有scripts/mod/modpost，那我们就编译它吧
[root@liu-desktop linux26]# make scripts
HOSTCC scripts/genksyms/genksyms.o
SHIPPED scripts/genksyms/lex.c
SHIPPED scripts/genksyms/parse.h
SHIPPED scripts/genksyms/keywords.c
HOSTCC scripts/genksyms/lex.o
SHIPPED scripts/genksyms/parse.c
HOSTCC scripts/genksyms/parse.o
HOSTLD scripts/genksyms/genksyms
CC scripts/mod/empty.o
HOSTCC scripts/mod/mk_elfconfig
MKELF scripts/mod/elfconfig.h
HOSTCC scripts/mod/file2alias.o
HOSTCC scripts/mod/modpost.o
HOSTCC scripts/mod/sumversion.o
HOSTLD scripts/mod/modpost
HOSTCC scripts/kallsyms
HOSTCC scripts/conmakehash

OK，好了
[liu@liu-desktop hellomod]$ make -C /usr/src/linux26/ SUBDIRS=$PWD modules
make: Entering directory `/usr/src/linux26'

WARNING: Symbol version dump /usr/src/linux26/Module.symvers
is missing; modules will have no dependencies and modversions.

Building modules, stage 2.
MODPOST 1 modules
CC /home/liu/test/hellomod/hellomod.mod.o
LD [M] /home/liu/test/hellomod/hellomod.ko
make: Leaving directory `/usr/src/linux26'
[liu@liu-desktop hellomod]$ ls
hellomod.c hellomod.ko hellomod.mod.c hellomod.mod.o hellomod.o Makefile Module.symvers


[root@liu-desktop linux26]#insmod hellomod.ko

[root@liu-desktop linux26]#lsmod |grep hellomod
lsmod |grep hellomod

[root@liu-desktop linux26]#rmmod hellomod


注意：如果出现下面错误，那99％是内核版本号对不上，也就是version magic不对

insmod: error inserting 'hellomod.ko': -1 Invalid module format

此时，你用sudo tail /var/log/messages
你在最后一行应该看到类似下面的提示：

Dec 19 13:42:29 localhost kernel: hellomod: version magic '2.6.24.2 SMP mod_unload 686 4KSTACKS 'should be '2.6.27.7-134.fc10.i686 SMP mod_unload 686 4KSTACKS '

那该怎么办呢？最简单的办法就是：修改源目录下的Makefie
把
最Makefile第1－4行的值改为当前内核一样的值
VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 24
EXTRAVERSION = .2
NAME = Err Metey! A Heury Beelge-a Ret!

那怎么确定你当前内核的值是多少呢？

vi /lib/modules/`uname -r`/build/Makefile
现在知道了吧？