转了一圈，今天再次回到C
网上一篇博文，个人感觉良心作品，故而拿来重新实现一遍，原作者原文有问题，我这里把他打通了
一．GCC Makefile
//hello.c
#include <stdio.h>
#include <stdlib.h>
void main(void)
{
#ifdef DEBUG
printf("you ask for debug! ");
#endif
printf("we must say goodbye ");
return;
}
//Makefile
ifeq ($(DEBUG),y)
CFLAGS := $(CFLAGS) -DDEBUG
endif
hello: hello.c
$(CC) $(CFLAGS) $< -o $@
//result
# make
cc hello.c -o hello
# ./hello
we must say goodbye
# rm hello
# make DEBUG:=y
cc -DDEBUG hello.c -o hello
# ./hello
you ask for debug!
we must say goodbye
二．KBuild(kernel gcc) Makefile
//ville.c
/**
* * Author : ville lee villelee1987@gmail.com
* * Create Time : 2010/07/31
* * Description : This module implements a virtual file system.
* * Aimming at learning the theory of Linux VFS.
* *
* * Change Log :
* * version author Date Log
* *
* *
* *
* * */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
/**
* * init function of the module
* *
* * */
static int __init
ville_init(void)
{
#ifdef DEBUG
/* we give the debug message like: module name : function name : debug message */
printk(KERN_ALERT "ville :ville_init: you ask for debug! ");
#endif
printk(KERN_ALERT "ville :ville_init: ville module init! ");
return 0;
}
static void __exit
ville_exit(void)
{
#ifdef DEBUG
/* we give the debug message like: module name : function name : debug message */
printk(KERN_ALERT "ville :ville_exit: you ask for debug! ");
#endif
printk(KERN_ALERT "ville :ville_exit: ville module exit! ");
return;
}
module_init(ville_init);
module_exit(ville_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("ville lee");
//Makefile
## if module is built in the kernel module
## system. Give the work to kbuild.
# provide the default value to module name and ccflags-y
ifeq ($(MODULE),)
MODULE := ville
endif
ifeq ($(DEBUG),y)
ccflags-y += -DDEBUG
endif
ifneq ($(KERNELRELEASE),)
obj-m := $(MODULE).o
else
KERNELDIR := /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
endif
.PHONY:clean
clean:
echo "cleaning ...."
rm modules.order Module.symvers
$(MODULE).ko $(MODULE).mod.c
$(MODULE).mod.o $(MODULE).o
echo "clean up"
//result
# make
make -C /lib/modules/4.13.0-17-generic/build M=/home/woodzcl/c_develop/KMF modules
make[1]: Entering directory '/usr/src/linux-headers-4.13.0-17-generic'
CC [M] /home/woodzcl/c_develop/KMF/ville.o
Building modules, stage 2.
MODPOST 1 modules
CC /home/woodzcl/c_develop/KMF/ville.mod.o
LD [M] /home/woodzcl/c_develop/KMF/ville.ko
make[1]: Leaving directory '/usr/src/linux-headers-4.13.0-17-generic'
# insmod ville.ko
# rmmod ville
# cat /var/log/kern.log
Nov 22 22:05:35 ubuntu kernel: [ 1495.967374] ville :ville_init: ville module init!
Nov 22 22:05:39 ubuntu kernel: [ 1500.103238] ville :ville_exit: ville module exit!
# make clean
echo "cleaning ...."
cleaning ....
rm modules.order Module.symvers
ville.ko ville.mod.c
ville.mod.o ville.o
echo "clean up"
clean up
# make DEBUG:=y
make -C /lib/modules/4.13.0-17-generic/build M=/home/woodzcl/c_develop/KMF modules
make[1]: Entering directory '/usr/src/linux-headers-4.13.0-17-generic'
CC [M] /home/woodzcl/c_develop/KMF/ville.o
Building modules, stage 2.
MODPOST 1 modules
CC /home/woodzcl/c_develop/KMF/ville.mod.o
LD [M] /home/woodzcl/c_develop/KMF/ville.ko
make[1]: Leaving directory '/usr/src/linux-headers-4.13.0-17-generic'
# insmod ville.ko
# rmmod ville
# cat /var/log/kern.log
Nov 22 22:08:40 ubuntu kernel: [ 1680.874360] ville :ville_init: you ask for debug!
Nov 22 22:08:40 ubuntu kernel: [ 1680.874362] ville :ville_init: ville module init!
Nov 22 22:08:44 ubuntu kernel: [ 1685.649839] ville :ville_exit: you ask for debug!
Nov 22 22:08:44 ubuntu kernel: [ 1685.649841] ville :ville_exit: ville module exit!
Finally:
最后，发现自己还是个C程序员而已。
哎，但是改变还是要继续，时代在前进，我们每一个老东西都不能落后啊：）哈哈哈哈哈哈哈哈哈哈哈哈