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分类: 嵌入式
2014-09-16 17:06:52
One of the things that we've attempted to do with OpenWrt's template system is make it incredibly easy to port software to OpenWrt. If you look at a typical package directory in OpenWrt you'll find two things:
The patches directory is optional and typically contains bug fixes or optimizations to reduce the size of the executable. The files directory is optional. It typically includes default config or init files.
The package makefile is the important item because it provides the steps actually needed to download and compile the package.
Looking at one of the package makefiles, you'd hardly recognize it as a makefile. Through what can only be described as blatant disregard and abuse of the traditional make format, the makefile has been transformed into an object oriented template which simplifies the entire ordeal.
Here for example, is package/bridge/Makefile:
include $(TOPDIR)/rules.mk PKG_NAME:=bridge PKG_VERSION:=1.0.6 PKG_RELEASE:=1 PKG_BUILD_DIR:=$(BUILD_DIR)/bridge-utils-$(PKG_VERSION) PKG_SOURCE:=bridge-utils-$(PKG_VERSION).tar.gz PKG_SOURCE_URL:=@SF/bridge PKG_MD5SUM:=9b7dc52656f5cbec846a7ba3299f73bd PKG_CAT:=zcat include $(INCLUDE_DIR)/package.mk define Package/bridge SECTION:=base CATEGORY:=Network TITLE:=Ethernet bridging configuration utility #DESCRIPTION:=This variable is obsolete. use the Package/name/description define instead! URL:= endef define Package/bridge/description Ethernet bridging configuration utility Manage ethernet bridging; a way to connect networks together to form a larger network. endef define Build/Configure $(call Build/Configure/Default,--with-linux-headers=$(LINUX_DIR)) endef define Package/bridge/install $(INSTALL_DIR) $(1)/usr/sbin $(INSTALL_BIN) $(PKG_BUILD_DIR)/brctl/brctl $(1)/usr/sbin/ endef $(eval $(call BuildPackage,bridge))
As you can see, there's not much work to be done; everything is hidden in other makefiles and abstracted to the point where you only need to specify a few variables.
The PKG_* variables define where to download the package from; @SF is a special keyword for downloading packages from sourceforge. The md5sum is used to verify the package was downloaded correctly and PKG_BUILD_DIR defines where to find the package after the sources are uncompressed into $(BUILD_DIR). PKG_INSTALL_DIR defines where the files will be copied after calling "make install" (set with the PKG_INSTALL variable), and after that you can package them in the install section.
At the bottom of the file is where the real magic happens, "BuildPackage" is a macro setup by the earlier include statements. BuildPackage only takes one argument directly – the name of the package to be built, in this case "bridge". All other information is taken from the define blocks. This is a way of providing a level of verbosity, it's inherently clear what the DESCRIPTION variable in Package/bridge is, which wouldn't be the case if we passed this information directly as the Nth argument to BuildPackage.
Some makefiles need fixup (because of crosscompile bugs ?)
PKG_FIXUP:=autoreconf PKG_FIXUP:=autoreconf -fi PKG_FIXUP:=libtool PKG_FIXUP:=libtool autoreconf PKG_FIXUP:=libtool no-autoreconf PKG_FIXUP:=libtool-ucxx PKG_FIXUP:=patch-libtool
Packages that are using Autotools should work with autoreconf fixup. However there might be issues with required versions.
Instead of patching ./configure one should fix the file from which ./configure is generated in autotools: configure.ac / configure.in.
TODO What are the differences ?
matches the argument passed to buildroot, this describes the package the menuconfig and ipkg entries. Within Package/ you can define the following variables:
A list of config files installed by this package, one file per line.
A free text description of the package
A set of commands to unpack and patch the sources. You may safely leave this undefined.
You can leave this undefined if the source doesn't use configure or has a normal config script, otherwise you can put your own commands here or use "$(call Build/Configure/Default,)" as above to pass in additional arguments for a standard configure script.
How to compile the source; in most cases you should leave this undefined, because then the default is used, which calls make. If you want to pass special arguments to make, use e.g. "$(call Build/Compile/Default,FOO=bar)
How to install the compiled source. The default is to call make install. Again, to pass special arguments or targets, use $(call Build/Install/Default,install install-foo) Note that you need put all the needed make arguments here. If you just need to add something to the "install" argument, don't forget the 'install' itself.
For things needed to compile packages against it (static libs, header files), but that are of no use on the target device.
A set of commands to copy files into the ipkg which is represented by the $(1) directory. As source you can use relative paths which will install from the unpacked and compiled source, or $(PKG_INSTALL_DIR) which is where the files in the Build/Install step above end up.
The actual text of the script which is to be executed before installation. Dont forget to include the #!/bin/sh. If you need to abort installation have the script return false.
The actual text of the script which is to be executed after installation. Dont forget to include the #!/bin/sh.
The actual text of the script which is to be executed before removal. Dont forget to include the #!/bin/sh. If you need to abort removal have the script return false.
The actual text of the script which is to be executed after removal. Dont forget to include the #!/bin/sh.
The reason that some of the defines are prefixed by "Package/" and others are simply "Build" is because of the possibility of generating multiple packages from a single source. OpenWrt works under the assumption of one source per package makefile, but you can split that source into as many packages as desired. Since you only need to compile the sources once, there's one global set of "Build" defines, but you can add as many "Package/" defines as you want by adding extra calls to BuildPackage – see the dropbear package for an example.
Various types of dependencies can be specified, which require a bit of explanation for their differences.
+ |
Package will depend on package |
|
Package will depend on package |
@FOO | Package depends on the config symbol CONFIG_FOO and will be invisible unless CONFIG_FOO is set. This usually used for depending on certain Linux versions or targets, e.g. @TARGET_foo will make a package only available for target foo. You can also use boolean expressions for complex dependencies, e.g. @(!TARGET_foo&&!TARGET_bar) will make the package unavailable for foo and bar. |
+FOO: |
Package will depend on |
@FOO: |
Package will depend on |
Some typical config symbols for (conditional) dependencies are:
TARGET_ |
Target |
TARGET_ |
If the target |
TARGET_ |
Target |
LINUX_3_X | Linux version used is 3.x.* |
LINUX_2_6_X | Linux version used is 2.6.x.* (:1: only used for backfire and earlier) |
LINUX_2_4 | Linux version is 2.4 ( only used in backfire and earlier, and only for target brcm-2.4) |
USE_UCLIBC, USE_GLIBC, USE_EGLIBC | To (not) depend on a certain libc. |
BROKEN | Package doesn't build or work, and should only be visible if "Show broken targets/packages" is selected. Prevents the package from failing builds by accidentally selecting it. |
IPV6 | IPv6 support in packages is selected. |
Example:
CONFIGURE_ARGS += \ --disable-native-affinity \ --disable-unicode \ --enable-hwloc CONFIGURE_VARS += \ ac_cv_file__proc_stat=yes \ ac_cv_file__proc_meminfo=yes \ ac_cv_func_malloc_0_nonnull=yes \ ac_cv_func_realloc_0_nonnull=yesTo set variables (autoconfig internal ones or CPPFLAGS,CFLAGS, CXXFLAGS, LDFLAGS for example) or configure arguments. Setting configure arguments is common. Setting VARS is needed when the configure.ac autoconf source script does not work well on cross compilation or finding libraries.
If your package needs some private tools built on the host, you can use the following snippet as a pointer of where to look for more info
HOST_BUILD_DEPENDS:=TODO Expand on how to use this, and include examples/host PKG_BUILD_DEPENDS:= /host include $(INCLUDE_DIR)/host-build.mk define Host/Compile define Host/Install $(eval $(call HostBuild))
Extracted from this thead on the devel mailing list: https://lists.openwrt.org/pipermail/openwrt-devel/2014-February/023970.html
All variables in your pre/post install/removal scripts should have double ($$) instead of a single ($) string characters. This will inform "make" to not interpret the value as a variable, but rather just ignore the string and replace the double $$ by a single $ –
After you've created your package Makefile, the new package will automatically show in the menu the next time you run "make menuconfig" and if selected will be built automatically the next time "make" is run.
DESCRIPTION is obsolete, use Package/PKG_NAME/description.
If you would like configure your package installation/compilation in the menuconfig you can do the following: Add MENU:=1 to your package definition like this:
define Package/mjpg-streamer SECTION:=multimedia CATEGORY:=Multimedia TITLE:=MJPG-streamer DEPENDS:=@!LINUX_2_4 +libpthread-stubs +jpeg URL:= MENU:=1 endef
Create a config key in the Makefile:
define Package/mjpg-streamer/config source "$(SOURCE)/Config.in" endef
Create a Config.in file directory where the Makefile is located with the content like this:
# Mjpg-streamer configuration menu "Configuration" depends on PACKAGE_mjpg-streamer config MJPEG_STREAMER_AUTOSTART bool "Autostart enabled" default n menu "Input plugins" depends on PACKAGE_mjpg-streamer config MJPEG_STREAMER_INPUT_FILE bool "File input plugin" help You can stream pictures from jpg files on the filesystem default n config MJPEG_STREAMER_INPUT_UVC bool "UVC input plugin" help You can stream pictures from an Universal Video Class compatible webcamera default y config MJPEG_STREAMER_FPS depends MJPEG_STREAMER_INPUT_UVC int "Maximum FPS" default 15 config MJPEG_STREAMER_PICT_HEIGHT depends MJPEG_STREAMER_INPUT_UVC int "Picture height" default 640 config MJPEG_STREAMER_PICT_WIDTH depends MJPEG_STREAMER_INPUT_UVC int "Picture width" default 480 config MJPEG_STREAMER_DEVICE depends MJPEG_STREAMER_INPUT_UVC string "Device" default /dev/video0 config MJPEG_STREAMER_INPUT_GSPCA bool "GSPCA input plugin" help You can stream pictures from a gspca supported webcamera Note this module is deprecated, use the UVVC plugin instead default n endmenu # ...... endmenu
Above you can see examples for various type config parameters.
And finally you can check your configuration parameters in your Makefile in the following way: (Note that you can reference to the parameters value with it name prefixed with CONFIG_)
ifeq ($(CONFIG_MJPEG_STREAMER_INPUT_UVC),y) $(CP) $(PKG_BUILD_DIR)/input_uvc.so $(1)/usr/lib endif
If you are still working on the application itself, at the same time as you are working on the packaging, it can be very useful to have OpenWrt build your work in progress code, rather than a specific version+md5sum combination checked out of revision control, or downloaded from your final "release" location. There are a few ways of doing this.
This is an option in menuconfig. See "Advanced configuration options (for developers)" → "Enable package source tree override"
This allows you to point to a local git tree. (And only git) Say your package is defined in my_cool_feed/awesome_app.
ln -s /path/to/local/awesome_app_tree/.git feeds/my_cool_feed/awesome_app/git-src make package/awesome_app/{clean,compile} V=s
Benefits of this approach are that you don't need any special infrastructure in your package makefiles, they stay completely as they would be for a final build. The downside is that it only builds whatever is currently _committed_ in HEAD of your local tree. (Not master, this could be a private testing branch, but it must be committed it can't be local changes) This will also use a _separate_ directory for building and checking out the code. So any built objects in your local git tree (for example, build targeting a different architecture) will be left alone, but whatever _branch_ is checked out in your tree determines where HEAD is.
As part of deprecating package-version-override.mk (below) a method to point directly to local source was introduced.
make package/awesome_app/clean V=s make package/awesome_app/prepare USE_SOURCE_DIR=~/src/awesome_src V=s make package/awesome_app/clean V=s(V=s is optional above)
This doesn't require any config change to enable rules, and doesn't require that you have a local git tree, and doesn't require any files to be committed.
At least at present however, this has the following problems:
See http://www.mail-archive.com/openwrt-devel@lists.openwrt.org/msg23122.html for the original discussion of this new feature
Don't use this anymore Support for this style of local source building was removed in: https://dev.openwrt.org/changeset/40392. This style required a permanent modification to your package makefile, and then entering a path via menuconfig to where the source was found. It was fairly easy to use, and didn't care whether your local source was in git or svn or visual source safe even, but it had the major downside that the "clean" target simply didn't work. (As it simply removed a symlink for cleaning)
If you build a current OpenWrt tree, with packages that still attempt to use this style of local building, you _will_ receive errors like so: ERROR: please fix package/feeds/feed_name/application_name/Makefile - see logs/package/feeds/feed_name/application_name/dump.txt for details
If you need/want to keep using this style, where it's available, make sure you include without failing if it was missing:
-include $(INCLUDE_DIR)/package-version-override.mk
A is an installable program which extends the behavior of the linux kernel. A kernel module gets loaded after the kernel itself, (e.g. using insmod).
Many kernel programs are included in the linux source distribution; typically the kernel build may be configured to, for each program,
See FIX:Customizingthekerneloptions customizing the kernel options for including it in the kernel.
To include one of these programs as a loadable module, select the corresponding kernel option in the OpenWrt configuration (see ). If your favorite kernel module does not appear in the OpenWrt configuration menus, you must add a stanza to one of the files in the package/kernel/linux/modules directory. Here is an example extracted from …/modules/block.mk:
define KernelPackage/loop SUBMENU:=$(BLOCK_MENU) TITLE:=Loopback device support KCONFIG:= \ CONFIG_BLK_DEV_LOOP \ CONFIG_BLK_DEV_CRYPTOLOOP=n FILES:=$(LINUX_DIR)/drivers/block/loop.ko AUTOLOAD:=$(call AutoLoad,30,loop) endef define KernelPackage/loop/description Kernel module for loopback device support endef $(eval $(call KernelPackage,loop))
Changes to the *.mk files are not automatically picked up by the build system. To force re-reading the meta data either touch the kernel package Makefile usingtouch package/kernel/linux/Makefile (on older revisions touch package/kernel/Makefile) or to delete the tmp/ directory of the buildroot.
You can also add kernel modules which are not part of the linux source distribution. In this case, a kernel module appears in the package/ directory, just as any other package does. The package/Makefile uses
KernelPackage/xxxdefinitions in place of
Package/xxxFor example, here is package/madwifi/Makefile:
# # Copyright (C) 2006 OpenWrt.org # # This is free software, licensed under the GNU General Public License v2. # See /LICENSE for more information. # # $Id$ include $(TOPDIR)/rules.mk include $(INCLUDE_DIR)/kernel.mk PKG_NAME:=madwifi PKG_VERSION:=0.9.2 PKG_RELEASE:=1 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2 PKG_SOURCE_URL:=@SF/$(PKG_NAME) PKG_MD5SUM:=a75baacbe07085ddc5cb28e1fb43edbb PKG_CAT:=bzcat PKG_BUILD_DIR:=$(KERNEL_BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION) include $(INCLUDE_DIR)/package.mk RATE_CONTROL:=sample ifeq ($(ARCH),mips) HAL_TARGET:=mips-be-elf endif ifeq ($(ARCH),mipsel) HAL_TARGET:=mips-le-elf endif ifeq ($(ARCH),i386) HAL_TARGET:=i386-elf endif ifeq ($(ARCH),armeb) HAL_TARGET:=xscale-be-elf endif ifeq ($(ARCH),powerpc) HAL_TARGET:=powerpc-be-elf endif BUS:=PCI ifneq ($(CONFIG_LINUX_2_4_AR531X),) BUS:=AHB endif ifneq ($(CONFIG_LINUX_2_6_ARUBA),) BUS:=PCI AHB # no suitable HAL for AHB yet. endif BUS_MODULES:= ifeq ($(findstring AHB,$(BUS)),AHB) BUS_MODULES+=$(PKG_BUILD_DIR)/ath/ath_ahb.$(LINUX_KMOD_SUFFIX) endif ifeq ($(findstring PCI,$(BUS)),PCI) BUS_MODULES+=$(PKG_BUILD_DIR)/ath/ath_pci.$(LINUX_KMOD_SUFFIX) endif MADWIFI_AUTOLOAD:= \ wlan \ wlan_scan_ap \ wlan_scan_sta \ ath_hal \ ath_rate_$(RATE_CONTROL) \ wlan_acl \ wlan_ccmp \ wlan_tkip \ wlan_wep \ wlan_xauth ifeq ($(findstring AHB,$(BUS)),AHB) MADWIFI_AUTOLOAD += ath_ahb endif ifeq ($(findstring PCI,$(BUS)),PCI) MADWIFI_AUTOLOAD += ath_pci endif define KernelPackage/madwifi SUBMENU:=Wireless Drivers DEFAULT:=y if LINUX_2_6_BRCM | LINUX_2_6_ARUBA | LINUX_2_4_AR531X | LINUX_2_6_XSCALE, m if ALL TITLE:=Driver for Atheros wireless chipsets DESCRIPTION:=\ This package contains a driver for Atheros 802.11a/b/g chipsets. URL:= VERSION:=$(LINUX_VERSION)+$(PKG_VERSION)-$(BOARD)-$(PKG_RELEASE) FILES:= \ $(PKG_BUILD_DIR)/ath/ath_hal.$(LINUX_KMOD_SUFFIX) \ $(BUS_MODULES) \ $(PKG_BUILD_DIR)/ath_rate/$(RATE_CONTROL)/ath_rate_$(RATE_CONTROL).$(LINUX_KMOD_SUFFIX) \ $(PKG_BUILD_DIR)/net80211/wlan*.$(LINUX_KMOD_SUFFIX) AUTOLOAD:=$(call AutoLoad,50,$(MADWIFI_AUTOLOAD)) endef MADWIFI_MAKEOPTS= -C $(PKG_BUILD_DIR) \ PATH="$(TARGET_PATH)" \ ARCH="$(LINUX_KARCH)" \ CROSS_COMPILE="$(TARGET_CROSS)" \ TARGET="$(HAL_TARGET)" \ TOOLPREFIX="$(KERNEL_CROSS)" \ TOOLPATH="$(KERNEL_CROSS)" \ KERNELPATH="$(LINUX_DIR)" \ LDOPTS=" " \ ATH_RATE="ath_rate/$(RATE_CONTROL)" \ DOMULTI=1 ifeq ($(findstring AHB,$(BUS)),AHB) define Build/Compile/ahb $(MAKE) $(MADWIFI_MAKEOPTS) BUS="AHB" all endef endif ifeq ($(findstring PCI,$(BUS)),PCI) define Build/Compile/pci $(MAKE) $(MADWIFI_MAKEOPTS) BUS="PCI" all endef endif define Build/Compile $(call Build/Compile/ahb) $(call Build/Compile/pci) endef define Build/InstallDev $(INSTALL_DIR) $(STAGING_DIR)/usr/include/madwifi $(CP) $(PKG_BUILD_DIR)/include $(STAGING_DIR)/usr/include/madwifi/ $(INSTALL_DIR) $(STAGING_DIR)/usr/include/madwifi/net80211 $(CP) $(PKG_BUILD_DIR)/net80211/*.h $(STAGING_DIR)/usr/include/madwifi/net80211/ endef define KernelPackage/madwifi/install $(INSTALL_DIR) $(1)/etc/init.d $(INSTALL_DIR) $(1)/lib/modules/$(LINUX_VERSION) $(INSTALL_DIR) $(1)/usr/sbin $(INSTALL_BIN) ./files/madwifi.init $(1)/etc/init.d/madwifi $(CP) $(PKG_BUILD_DIR)/tools/{madwifi_multi,80211debug,80211stats,athchans,athctrl,athdebug,athkey,athstats,wlanconfig} $(1)/usr/sbin/ endef $(eval $(call KernelPackage,madwifi))
INSTALL_DIR, INSTALL_BIN, INSTALL_DATA are used for creating a directory, copying an executable, or a data file. +x is set on the target file for INSTALL_BIN, independent of it's mode on the host.
From the big document:
Package/
A set of commands to copy files out of the compiled source and into the ipkg which is represented by the $(1) directory. Note that there are currently 4 defined install macros:
INSTALL_DIR install -d -m0755 INSTALL_BIN install -m0755 INSTALL_DATA install -m0644 INSTALL_CONF install -m0600
If you want to install a service, (something that should start/stop at boot time, that has a /etc/init.d/blah script), you should make sure that the init.d script can be run on the host. At image build time, all init.d scripts found are run on the host, looking for the START=20/STOP=99 lines.
This is what installs the symlinks in /etc/rc.d, so they are only created when you rebuild the entire image. If you want the symlinks to be created when a package is installed, such as via opkg, you should add a postinstall script which runs
/etc/init.d/foo enableif $IPKG_INSTROOT is empty. when $IPKG_INSTROOT is defined, you run within the buildroot, if it is empty you run on the target.
Example makefile snippet to install/remove symlinks.
define Package/mrelay/postinst #!/bin/sh # check if we are on real system if [ -z "$${IPKG_INSTROOT}" ]; then echo "Enabling rc.d symlink for mrelay" /etc/init.d/mrelay enable fi exit 0 endef define Package/mrelay/prerm #!/bin/sh # check if we are on real system if [ -z "$${IPKG_INSTROOT}" ]; then echo "Removing rc.d symlink for mrelay" /etc/init.d/mrelay disable fi exit 0 endef
Very basic example of a suitable init.d script
procd style init is used in some init.d scripts since: https://dev.openwrt.org/changeset/38023 . See for more details on that
#!/bin/sh /etc/rc.common # "new(er)" style init script # Look at /lib/functions/service.sh on a running system for explanations of what other SERVICE_ # options you can use, and when you might want them. START=80 APP=mrelay SERVICE_WRITE_PID=1 SERVICE_DAEMONIZE=1 start() { service_start /usr/bin/$APP } stop() { service_stop /usr/bin/$APP }
#!/bin/sh /etc/rc.common ########################################### # NOTE - this is an old style init script # ########################################### START=80 APP=mrelay PID_FILE=/var/run/$APP.pid start() { start-stop-daemon -S -x $APP -p $PID_FILE -m -b } stop() { start-stop-daemon -K -n $APP -p $PID_FILE -s TERM rm -rf $PID_FILE }