openWRT的ipk编译方法

编译时要配置内核，make menuconfig

配置Build the OpenWrt SDK ，前提条件是openwrt编译成功

1.在编译好的文件中会有/bin/ramips/OpenWrt-SDK-ramips-for-linux-x86_64-gcc-4.6-linaro_uClibc-0.9.33.2.tar.bz2文件
2.然后解压这个文件

tar xvf OpenWrt-SDK-ramips-for-linux-x86_64-gcc-4.6-linaro_uClibc-0.9.33.2.tar.bz2

进入这个sdk，会看见一个package，在下新建mkdir -p helloworld/src 两个目录

在目录src下新建helloworld.c

#include
#include 
int main(void)
{
    printf("Hell! O' world, why won't my code compile?\n\n");
    return 0;
}

然后在此目录下创建Makefile( 注意Makefile的语法要用tab)

# 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

然后返回上层目录，即helloworld目录，在此目录下创建一个Makefile

##############################################
# 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))

这里的Makefile文件要注意tab（如果是复制过去的话）

然后回到OpenWrt-SDK-ramips-for-linux-x86_64-gcc-4.6-linaro_uClibc-0.9.33.2目录执行make

编译过程会在build_dir目录下完成

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

说明编译成功

编译好的文件放置在 bin/[yourtarget]/package目录下