openWRT自学---对官方的开发指导文档的解读和理解记录1：编译一个package-白红宇

openWRT自学---对官方的开发指导文档的解读和理解记录1：编译一个package

阅读量：5087 次

发布时间：2019-06-13

本文共 7891 字，大约阅读时间需要 26 分钟。

针对的是：http://kamikaze.openwrt.org/docs/openwrt.html#x1-390002

1.If you want, you can also modify the kernel config for the selected target system. simply run "make kernel_menuconfig" and the build system will unpack the kernel sources (if necessary), run menuconfig inside of the kernel tree, and then copy the kernel config to target/linux/<platform>/config so that it is preserved over "make clean" calls. ---- 如果你愿意，你也可以修改内核配置为选定的目标系统。简单地运行“make kernel_menuconfig”和构建系统将解压缩内核源代码（如果有必要）。此命令会展示针对内核的配置选择界面，然后其结果再复制内核配置到目标/ linux的/<platform>/配置。这样得到的针对内核的.config文件，在"make clean"后依然是保留的。

2.During the build process, buildroot will download all sources to the "dl" directory and will start patching and compiling them in the "build_dir/<arch> " directory. When finished, the resulting firmware will be in the "bin" directory and packages will be in the "bin/packages" directory -- 在编译过程中，buildroot会将所有的源下载到“dl”目录下，并在“build_dir/<arch>”目录中对它们进行patch和编译。完成后，所产生的固件将在“bin”目录，而各个package将在“bin/packages"目录中

3.openwrt中的一个典型的package目录结构：

package/<name>/Makefile --- 必须存在；其作用是定义下载包和编译包的步骤

package/<name>/patches --- 可有可无；是对所下载包的修复和优化，即补丁

package/<name>/files --- 可有可无；是此包特有的启动脚本和配置文件

4.openwrt中的一个典型的package目录结构（以backfire的package/bridge-utils为例）。其makefile的内容如下：

# This is free software, licensed under the GNU General Public License v2.

# See /LICENSE for more information.

include $(TOPDIR)/rules.mk

include $(INCLUDE_DIR)/kernel.mk

PKG_NAME:=bridge-utils //The name of the package, as seen via menuconfig and ipkg。不过我在CPE上使用opkg list命令，看到的是bridge - 1.4-1；而通过make menuconfig看到的是 bridge（在Base System里面）。此外，在package中有一个bridge-utils；在feeds/package中也有一个。到底这些如何对应呢？

PKG_RELEASE:=1 //The version of this package Makefile

PKG_SOURCE_URL:=@SF/bridge //Where to download the sources from (no trailing slash), you can add multiple download sources by separating them with a and a carriage return. @SF表示从SourceForge下载

ifeq ($(CONFIG_LINUX_2_4),y)

PKG_VERSION:=1.0.6

PKG_MD5SUM:=9b7dc52656f5cbec846a7ba3299f73bd

endif

ifeq ($(CONFIG_LINUX_2_6),y)

PKG_VERSION:=1.4 //The upstream version number that we are downloading

PKG_MD5SUM:=0182fcac3a2b307113bbec34e5f1c673 //A checksum to validate the download

endif

PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz //The filename of the original sources，这里就是 bridge-utils-1.4.tar.gz

include $(INCLUDE_DIR)/package.mk //位于 backfire_10.03/include/package.mk，用于定义任何一个package下载的统一的方式脚本

define Package/bridge

SECTION:=net //The type of package (currently unused)

CATEGORY:=Base system //Which menu it appears in menuconfig: Network, Sound, Utilities, Multimedia ...

TITLE:=Ethernet bridging configuration utility //A short description of the package

URL:=http://bridge.sourceforge.net/ //Where to find the original software

endef

define Package/bridge/description

Manage ethernet bridging: a way to connect networks together to

form a larger network.

endef

CONFIGURE_ARGS += \

--with-linux-headers="$(LINUX_DIR)" \

define Build/Prepare //这是可选项。A set of commands to unpack and patch the sources. You may safely leave this undefined.

$(call Build/Prepare/Default)

( cd $(PKG_BUILD_DIR) ; \ //PKG_BUILD_DIR定义在下载包后将此包解压缩到$(BUILD_DIR)的具体位置。对于此bridge-util包，其位置在backfire_10.03/build_dir/linux-brcm47xx/bridge-utils-1.4 中；同时这就说明用的是package中的，而不是feeds/package中的

[ -f ./configure ] || { \

ln -sf configure.in configure.ac ; \

autoconf ; \

} \

)

endef

define Package/bridge/install

$(INSTALL_DIR) $(1)/usr/sbin //$(INSTALL_DIR)即为：install -d -m0755

$(INSTALL_BIN) $(PKG_BUILD_DIR)/brctl/brctl $(1)/usr/sbin/ //$(INSTALL_BIN)即为: install -m0755

endef

$(eval $(call BuildPackage,bridge)) //这是真正开始执行的位置。BuildPackage定义在package.mk中，其调用的参数是bridge。这样就会走到package.mk中的：define BuildPackage

$(Build/IncludeOverlay)

$(eval $(Package/Default))

$(eval $(Package/$(1))) //对应就是$(Package/bridge)，从而又找到package/bridge-utils/Makefile中的 define Package/bridge 位置。

再举一个稍微复杂的例子，package/dropbear（一个轻量级的ssh客户端与服务端开源），其目录中包含了：files（内含配置文件和启动脚本），patches（内含补丁）和Makefile；如下是Makefile：

# This is free software, licensed under the GNU General Public License v2.

# See /LICENSE for more information.

include $(TOPDIR)/rules.mk

PKG_NAME:=dropbear //The name of the package, as seen via menuconfig and ipkg

PKG_VERSION:=0.52 //The upstream version number that we are downloading

PKG_RELEASE:=4 //The version of this package Makefile

PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz //The filename of the original sources，这里就是 dropbear-0.52.tar.gz

PKG_SOURCE_URL:= \ //下载源码包的url地址，这里就写了多个地址，用回车换行+一个斜杠来排列表示

http://matt.ucc.asn.au/dropbear/releases/ \

http://www.mirrors.wiretapped.net/security/cryptography/apps/ssh/dropbear/

PKG_MD5SUM:=1c69ec674481d7745452f68f2ea5597e //MD5校验和

include $(INCLUDE_DIR)/package.mk //实际是include了 backfire_10.03/include/package.mk

define Package/dropbear/Default

URL:=http://matt.ucc.asn.au/dropbear/ //Where to find the original software

endef

define Package/dropbear //由 BuildPackage 命令调用

$(call Package/dropbear/Default)

SECTION:=net //The type of package (currently unused)

CATEGORY:=Base system //Which menu it appears in menuconfig: Network, Sound, Utilities, Multimedia ...

TITLE:=Small SSH2 client/server //A short description of the package

endef

define Package/dropbear/description

A small SSH2 server/client designed for small memory environments.

endef

define Package/dropbear/conffiles //此项可选，A list of config files installed by this package, one file per line.表示此package会安装的一些配置文件

/etc/dropbear/dropbear_rsa_host_key

/etc/dropbear/dropbear_dss_host_key

/etc/config/dropbear

endef

define Package/dropbearconvert //这是另一个package，也是从dropbear的源码包里面会得到的。

$(call Package/dropbear/Default)

SECTION:=utils

CATEGORY:=Utilities

TITLE:=Utility for converting SSH keys

endef

CONFIGURE_ARGS += \

--with-shared \

--disable-pam \

--enable-openpty \

--enable-syslog \

$(if $(CONFIG_SHADOW_PASSWORDS),,--disable-shadow) \

--disable-lastlog \

--disable-utmp \

--disable-utmpx \

--disable-wtmp \

--disable-wtmpx \

--disable-loginfunc \

--disable-pututline \

--disable-pututxline \

--disable-zlib

define Build/Configure //此项可选。用于编译时传递一些自定义参数

$(SED) 's,^/\* #define PKG_MULTI.*,#define PKG_MULTI,g' $(PKG_BUILD_DIR)/options.h

$(SED) 's,^#define DO_HOST_LOOKUP,/* & */,g' $(PKG_BUILD_DIR)/options.h

$(call Build/Configure/Default)

endef

define Build/Compile //此项可选。表示如何编译源码包

$(MAKE) -C $(PKG_BUILD_DIR) \

$(TARGET_CONFIGURE_OPTS) \

LD="$(TARGET_CC)" \

PROGRAMS="dropbear dbclient dropbearkey scp" \

MULTI=1 SCPPROGRESS=1

$(MAKE) -C $(PKG_BUILD_DIR) \

$(TARGET_CONFIGURE_OPTS) \

LD="$(TARGET_CC)" \

PROGRAMS="dropbearconvert"

endef

define Package/dropbear/install //A set of commands to copy files out of the compiled source and into the ipkg which is represented by the $(1) directory

$(INSTALL_DIR) $(1)/usr/sbin

$(INSTALL_BIN) $(PKG_BUILD_DIR)/dropbearmulti $(1)/usr/sbin/dropbear

$(INSTALL_DIR) $(1)/usr/bin

ln -sf ../sbin/dropbear $(1)/usr/bin/scp

ln -sf ../sbin/dropbear $(1)/usr/bin/ssh

ln -sf ../sbin/dropbear $(1)/usr/bin/dbclient

ln -sf ../sbin/dropbear $(1)/usr/bin/dropbearkey

$(INSTALL_DIR) $(1)/etc/config

$(INSTALL_DATA) ./files/dropbear.config $(1)/etc/config/dropbear

$(INSTALL_DIR) $(1)/etc/init.d

$(INSTALL_BIN) ./files/dropbear.init $(1)/etc/init.d/dropbear

$(INSTALL_DIR) $(1)/usr/lib/opkg/info