- Hello,world:
1.編寫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.編寫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.在命令行下輸入： insmod ./hello.ko(注：此文件即生成的文件)
然后進入到/var/log/messages下面打開，看到最后顯示的是：
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!
同時，使用命令查看mod: lsmod，會發現此時模塊就又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.在命令行下輸入： rmmod ./hello.ko
刪除該模塊，發現/var/log/messages文件中的內容最后是：
Mar 6 19:09:02 liuchang-laptop kernel: [ 8791.665905] I will shut down myself in kernel mod!
此時再觀察模塊，內容為：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說明該模塊被刪除了。
- 至此，表示該模塊能夠正確的掛載和卸載。剩下來的問題，就是如何實現字符設備的一個具體的應用了。
posted on 2010-03-06 22:29
deercoder 閱讀(1022)
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