- Hello,world:
1.编写hello.c文件如下：
#include "/usr/src/linux-2.6.31.12/include/linux/kernel.h"
#include "/usr/src/linux-2.6.31.12/include/config/modules.h"
#if CONFIG_MODVERSIONS == 1
#define MODVERSIONS
#include "/usr/src/linux-2.6.31.12/include/linux/version.h"
#endif
int init_module()
{
printk("Hello,world!\n");
printk("I am running in a kernel mod!\n");
return 0;
}
void cleanup_module()
{
printk("I will shut down myself in kernel mod!\n");
}
2.编写Makefile如下：
# If KERNELRELEASE is defined, we've been invoked from the
# kernel build system and can use its language.
ifeq ($(KERNELRELEASE),)
# Assume the source tree is where the running kernel was built
# You should set KERNELDIR in the environment if it's elsewhere
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
# The current directory is passed to sub-makes as argument
PWD := $(shell pwd)
modules:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
modules_install:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions
.PHONY: modules modules_install clean
else
# called from kernel build system: just declare what our modules are
obj-m := hello.o
endif
3.在命令行下输入： insmod ./hello.ko(注：此文件即生成的文件)
然后进入到/var/log/messages下面打开，看到最后显示的是：
Mar 6 19:03:42 liuchang-laptop kernel: [ 8472.343068] Hello,world!
Mar 6 19:03:42 liuchang-laptop kernel: [ 8472.343074] I am running in a kernel mod!
同时，使用命令查看mod: lsmod，会发现此时模块就又hello
如下：
root@liuchang-laptop:/home/liuchang/桌面/test3# lsmod
Module Size Used by
hello 1052 0
nls_iso8859_1 3740 0
nls_cp437 5372 0
vfat 10716 0
fat 51452 1 vfat
usb_storage 52544 0
4.在命令行下输入： rmmod ./hello.ko
删除该模块，发现/var/log/messages文件中的内容最后是：
Mar 6 19:09:02 liuchang-laptop kernel: [ 8791.665905] I will shut down myself in kernel mod!
此时再观察模块，内容为：lsmod
nls_iso8859_1 3740 0
nls_cp437 5372 0
vfat 10716 0
fat 51452 1 vfat
usb_storage 52544 0
binfmt_misc 8356 1
ppdev 6688 0
snd_hda_codec_nvhdmi 4828 1
不再含有hello说明该模块被删除了。
- 至此，表示该模块能够正确的挂载和卸载。剩下来的问题，就是如何实现字符设备的一个具体的应用了。
posted on 2010-03-06 22:29
deercoder 阅读(992)
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