【转】OpenWRT开发自定义应用方法

【转】OpenWRT开发自定义应用方法

转自：http://blog.csdn.net/rudyn/article/details/38616783

　　OpenWRT编译成功完成后，所有的产品都会放在编译根目录下的bin/{TARGET}/，例如:我所编译的产物都放在./bin/ar74xx/下，其中有一个packages文件夹:里面包含了我们在配置文件里设定的所有编译好的软件包。默认情况下，会有默认选择的软件包。需要主要的是，编译完成后，一定要将编译好的bin目录进行备份。

　　在编译根目录下会有一个dl的目录，这个目录其实是“download”的简写，在编译前期，需要从网络下载的数据包都会放在这个目录下，这些软件包的一个特点就是，会自动安装在所编译的固件中，也就是我们make menuconfig的时候，为固件配置的一些软件包。如果我们需要更改这些源码包，只需要将更改好的源码包打包成相同的名字放在这个目录下，然后开始编译即可。编译时，会将软件包解压到build_dir目录下。当然，你也可以自己在dl里面创建自己的软件包，然后更改相关的配置文件，让openwrt可以识别这个文件包。

　　新建和编译自己的packages：

　　对于自己新建的package，而这个package又不需要随固件一起安装，换句话说，就是可以当做一个可选软件包的话。我们可以利用我们的SDK环境来单独编译，编译后会生成一个ipk的文件包。然后利用opkg install xxx.ipk 来安装这个软件，在package文件夹里面新建Helloworld，建立源码目录：

cd package
mkdir Helloworld ; cd Helloworld
mkdir src
touch src/Makefile   /* Helloworld 编译Makefile */
touch ./Makefile /*建立顶层Makefile，这个Makefile文件是OpenWRT读的*/

　　Helloworld.c程序：

/****************
* Helloworld.c
*****************/  

#include <stdio.h>
#include <unistd.h>
int main(void)
{
     printf("Hello world\n");
     return 0;
}

　　编辑Helloworld的编译Makefile:

# build helloworld executable when user executes "make"  

helloworld: helloworld.o
        $(CC) $(LDFLAGS) helloworld.o -o helloworld  

helloworld.o: helloworld.c
        $(CC) $(CFLAGS) -c helloworld.c  

# remove object files and executable when user executes "make clean"
clean:
        rm *.o helloworld

　　编写模块编译Makefile:

Makefile文件模板内容如下：
##############################################
# OpenWrt Makefile for helloworld program
#
#
# Most of the variables used here are defined in
# the include directives below. We just need to
# specify a basic description of the package,
# where to build our program, where to find
# the source files, and where to install the
# compiled program on the router.
#
# Be very careful of spacing in this file.
# Indents should be tabs, not spaces, and
# there should be no trailing whitespace in
# lines that are not commented.
#
##############################################  

include $(TOPDIR)/rules.mk  

# Name and release number of this package
PKG_NAME:=helloworld
PKG_RELEASE:=1  

# This specifies the directory where we're going to build the program.
# The root build directory, $(BUILD_DIR), is by default the build_mipsel
# directory in your OpenWrt SDK directory
PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)  

include $(INCLUDE_DIR)/package.mk  

# Specify package information for this program.
# The variables defined here should be self explanatory.
# If you are running Kamikaze, delete the DESCRIPTION
# variable below and uncomment the Kamikaze define
# directive for the description below
define Package/helloworld
        SECTION:=utils
        CATEGORY:=Utilities
        TITLE:=Helloworld -- prints a snarky message
endef  

# Uncomment portion below for Kamikaze and delete DESCRIPTION variable above
define Package/helloworld/description
        If you can't figure out what this program does, you're probably
        brain-dead and need immediate medical attention.
endef  

# Specify what needs to be done to prepare for building the package.
# In our case, we need to copy the source files to the build directory.
# This is NOT the default.  The default uses the PKG_SOURCE_URL and the
# PKG_SOURCE which is not defined here to download the source from the web.
# In order to just build a simple program that we have just written, it is
# much easier to do it this way.
define Build/Prepare
        mkdir -p $(PKG_BUILD_DIR)
        $(CP) ./src/* $(PKG_BUILD_DIR)/
endef  

# We do not need to define Build/Configure or Build/Compile directives
# The defaults are appropriate for compiling a simple program such as this one  

# Specify where and how to install the program. Since we only have one file,
# the helloworld executable, install it by copying it to the /bin directory on
# the router. The $(1) variable represents the root directory on the router running
# OpenWrt. The $(INSTALL_DIR) variable contains a command to prepare the install
# directory if it does not already exist.  Likewise $(INSTALL_BIN) contains the
# command to copy the binary file from its current location (in our case the build
# directory) to the install directory.
define Package/helloworld/install
        $(INSTALL_DIR) $(1)/bin
        $(INSTALL_BIN) $(PKG_BUILD_DIR)/helloworld $(1)/bin/
endef  

# This line executes the necessary commands to compile our program.
# The above define directives specify all the information needed, but this
# line calls BuildPackage which in turn actually uses this information to
# build a package.
$(eval $(call BuildPackage,helloworld))

　　

返回目录最顶层，执行make menuconfig，在utils中选中刚加的模块名（这里是根据sections中定义的），保存.config。

执行make.

如果要单独编译模块：

makepackage/helloworld/compile
make package/helloworld/install

　　

编译结果会放在bin/{TARGET}/package目录下:helloworld*.ipk

利用tftp将ipk文件上传到板子里面，用opkg install 命令加载模块，加载成功后执行helloworld，这时就是执行之前编写的helloworld程序

参考资料：http://wenku.baidu.com/view/31a903befd0a79563c1e7275.html