openwrt插件都是以.ipk方式发布的，ipk可以直接通过opkg安装到系统。上文我们编译了简单的hello，本文探究hello.ipk的编译过程。

一. 环境准备


cd ~/openwrt/bin/ar71xx
tar -xjvf OpenWrt-SDK-ar71xx-for-linux-x86_64-gcc-4.6-linaro_uClibc-0.9.33.2.tar.bz    #解压SDK包
cd OpenWrt-SDK-ar71xx-for-linux-x86_64-gcc-4.6-linaro_uClibc-0.9.33.2/package     #进入package目录

mkdir hello      #建立软件包目录



  

目录层次：
package/hello
               |--- /src/hello.c

               |--- /src/Makefile
               |--- Makefile

 

二. 编码
1. 编辑编译hello的Makefile
vi hello/src/Makefile

hello: hello.o
  $(CC) $(LDFLAGS) hello.o -o hello
hello.o: hello.c
  $(CC) $(CFLAGS) -c hello.c

clean:
  rm *.o hello



 
2. 编辑发布hello.ipk的Makefile
vi hello/Makefile

#Makefile
include $(TOPDIR)/rules.mk

# Nameand release number of this package
PKG_NAME:=hello
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 youare running Kamikaze, delete the DESCRIPTION
# variable below and uncomment the Kamikaze define
# directivefor the description below
define Package/hello
  SECTION:=utils
  CATEGORY:=Utilities
  TITLE:=Helloworld-- prints a snarky message
endef


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

# We donot need to define Build/Configure or Build/Compile directives
# Thedefaults are appropriate for compiling a simple program such as this one
# Specifywhere and how to install the program. Since we only have one file,
# thehello executable, install it by copying it to the /bin directory on
# therouter. 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
# commandto copy the binary file from its current location (in our case the build
#directory) to the install directory.
define Package/hello/install
  $(INSTALL_DIR) $(1)/bin
  $(INSTALL_BIN) $(PKG_BUILD_DIR)/hello $(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 apackage.
$(eval $(call BuildPackage,hello))



 

三. 编译



cd ~/openwrt/bin/ar71xx/OpenWrt-SDK-ar71xx-for-linux-x86_64-gcc-4.6-linaro_uClibc-0.9.33.2    #sdk根目录
make    #编译



    如果顺利，会出现以下信息：

    



make[1]  world
make[2]  package/compile
make[3]  -C package/hello compile
make[2]  package/index



    编译成功会在 bin/arr71xx/packages 下生成 hello_1_ar71xx.ipk 

四. 上传并测试

 

openwrt 下编译ipk_bc