添加一个自己的工程到openWrt

最新推荐文章于 2021-03-21 06:50:50 发布

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最新推荐文章于 2021-03-21 06:50:50 发布

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分类专栏： openWRT 文章标签： build compilation include variables dependencies library

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添加了一把，还没编译不知道能不能成功。

http://downloads.openwrt.org/docs/buildroot-documentation.html

Extending OpenWrt with more software

This section will only consider the case in which you want to add user-space software.

Package directory

First of all, create a directory under the package directory for your software, for example foo.

`Config.in` file

Then, create a file named Config.in. This file will contain the portion of options description related to our foo software that will be used and displayed in the configuration tool. It should basically contain :

config BR2_PACKAGE_FOO
        tristate "foo - some nice tool"
        default m if CONFIG_DEVEL
        help
	     This is a comment that explains what foo is.

If you depend on other software or library inside the Buildroot, it is important that you automatically select these packages in your Config.in. Example if foo depends on bar library:

config BR2_PACKAGE_FOO
        tristate "foo - some nice tool"
        default m if CONFIG_DEVEL
	select BR2_PACKAGE_LIBBAR
        help
        This is a comment that explains what foo is.

Of course, you can add other options to configure particular things in your software.

`Config.in` in the package directory

To add your package to the configuration tool, you need to add the following line to package/Config.in, please add it to a section, which fits the purpose of foo:

comment "Networking"
source "package/foo/Config.in"

`Makefile` in the package directory

To add your package to the build process, you need to edit the Makefile in the package/ directory. Locate the lines that look like the following:

package-$(BR2_PACKAGE_FOO) += foo

As you can see, this short line simply adds the target foo to the list of targets handled by OpenWrt Buildroot.

In addition to the default dependencies, you make your package depend on another package (e.g. a library) by adding a line:

foo-compile: bar-compile

The ipkg control file

Additionally, you need to create a control file which contains information about your package, readable by the ipkg package utility. It should be created as file: package/foo/ipkg/foo.control

The file looks like this

     1  Package: foo
     2  Priority: optional
     3  Section: net
     4  Maintainer: Foo Software <foo@foosoftware.com>
     5  Source: http://foosoftware.com
     6  Depends: libbar
     7  Description: Package Description

You can skip the usual Version: and Architecture fields, as they will be generated by the make-ipkg-dir.sh script called from your Makefile. The Depends field is important, so that ipkg will automatically fetch all dependend software on your target system.

The real Makefile

Finally, here's the hardest part. Create a file named Makefile. It will contain the Makefile rules that are in charge of downloading, configuring, compiling and installing the software. Below is an example that we will comment afterwards.

     1  # $Id: buildroot-documentation.html 2860 2006-01-08 02:17:18Z wbx $
     2	
     3  include $(TOPDIR)/rules.mk
     4
     5  PKG_NAME:=foo
     6  PKG_VERSION:=1.0
     7  PKG_RELEASE:=1
     8  PKG_MD5SUM:=4584f226523776a3cdd2fb6f8212ba8d
     9 
    10  PKG_SOURCE_URL:=http://www.foosoftware.org/downloads
    11  PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
    12 	PKG_CAT:=zcat
    13	
    14	PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
    15	PKG_INSTALL_DIR:=$(PKG_BUILD_DIR)/ipkg-install
    16
    17	include $(TOPDIR)/package/rules.mk
    18
    19	$(eval $(call PKG_template,FOO,foo,$(PKG_VERSION)-$(PKG_RELEASE),$(ARCH)))
    20
    21  $(PKG_BUILD_DIR)/.configured: $(PKG_BUILD_DIR)/.prepared
    22          (cd $(PKG_BUILD_DIR); /
    23                  $(TARGET_CONFIGURE_OPTS) /
    24                  CFLAGS="$(TARGET_CFLAGS)" /
    25                  ./configure /
    26                  --target=$(GNU_TARGET_NAME) /
    27                  --host=$(GNU_TARGET_NAME) /
    28                  --build=$(GNU_HOST_NAME) /
    29                  --prefix=/usr /
    30                  --sysconfdir=/etc /
    31 			--with-bar="$(STAGING_DIR)/usr" /
    32          );
    33          touch $@
    34
    35  $(PKG_BUILD_DIR)/.built:
    36      	rm -rf $(PKG_INSTALL_DIR)
    37		mkdir -p $(PKG_INSTALL_DIR)
    38		$(MAKE) -C $(PKG_BUILD_DIR) /
    39 	          $(TARGET_CONFIGURE_OPTS) /
    40            install_prefix="$(PKG_INSTALL_DIR)" /
    41 	          all install
    42		touch $@
    43 
    44  $(IPKG_FOO):
    46		install -d -m0755 $(IDIR_FOO)/usr/sbin
    47    	cp -fpR $(PKG_INSTALL_DIR)/usr/sbin/foo $(IDIR_FOO)/usr/sbin
    49		$(RSTRIP) $(IDIR_FOO)
    50		$(IPKG_BUILD) $(IDIR_FOO) $(PACKAGE_DIR)
    51	
    52	mostlyclean:
    53  	make -C $(PKG_BUILD_DIR) clean
    54    	rm $(PKG_BUILD_DIR)/.built

First of all, this Makefile example works for a single binary software. For other software such as libraries or more complex stuff with multiple binaries, it should be adapted. Look at the other Makefile files in the package/directory.

At lines 5-15, a couple of useful variables are defined:

PKG_NAME : The package name, e.g. foo.
PKG_VERSION : The version of the package that should be downloaded.
PKG_RELEASE : The release number that will be appended to the version number of your ipkg package.
PKG_MD5SUM : The md5sum of the software archive.
PKG_SOURCE_URL : Space separated list of the HTTP or FTP sites from which the archive is downloaded. It must include the complete path to the directory where FOO_SOURCE can be found.
PKG_SOURCE : The name of the tarball of your package on the download website of FTP site. As you can see PKG_NAME and PKG_VERSION are used.
PKG_CAT : The tool needed for extraction of the software archive.
PKG_BUILD_DIR : The directory into which the software will be configured and compiled. Basically, it's a subdirectory of BUILD_DIR which is created upon extraction of the tarball.
PKG_INSTALL_DIR : The directory into the software will be installed. It is a subdirectory of PKG_BUILD_DIR.

In Line 3 and 17 we include common variables and routines to simplify the process of ipkg creation. It includes routines to download, verify and extract the software package archives.

Line 19 contains the magic line which automatically creates the ipkg for us.

Lines 21-33 defines a target and associated rules that configures the software. It depends on the previous target (the hidden .prepared file) so that we are sure the software has been uncompressed. In order to configure it, it basically runs the well-known ./configurescript. As we may be doing cross-compilation, target, host and build arguments are given. The prefix is also set to /usr, not because the software will be installed in /usr on your host system, but in the target filesystem. Finally it creates a .configured file to mark the software as configured.

Lines 35-42 defines a target and a rule that compiles the software. This target will create the binary file in the compilation directory, and depends on the software being already configured (hence the reference to the.configured file). Afterwards it installs the resulting binary into the PKG_INSTALL_DIR. It basically runs make install inside the source directory.

Lines 44-50 defines a target and associated rules that create the ipkg package, which can optionally be embedded into the resulting firmware image. It manually installs all files you want to integrate in your resulting ipkg. RSTRIPwill recursevily strip all binaries and libraries. Finally IPKG_BUILD is called to create the package.

Conclusion

As you can see, adding a software to buildroot is simply a matter of writing a Makefile using an already existing example and to modify it according to the compilation process of the software.

If you package software that might be useful for other persons, don't forget to send a patch to OpenWrt developers! Use the mail address: openwrt-devel@openwrt.org