swap logic on squashfs version selection

[openwrt.git] / docs / build.tex

diff --git a/docs/build.tex b/docs/build.tex
index fed0ca2..3a9088a 100644 (file)
--- a/docs/build.tex
+++ b/docs/build.tex
@@ -39,17 +39,17 @@ with the latest compilers, latest kernels and latest applications.
 So let's take a look at OpenWrt and see how this all works.
 
 
 So let's take a look at OpenWrt and see how this all works.
 
 

-\subsubsection{Download openwrt}
+\subsubsection{Download OpenWrt}

 
 This article refers to the "Kamikaze" branch of OpenWrt, which can be downloaded via
 subversion using the following command:
 
 \begin{Verbatim}
 
 This article refers to the "Kamikaze" branch of OpenWrt, which can be downloaded via
 subversion using the following command:
 
 \begin{Verbatim}

-$ svn co https://svn.openwrt.org/openwrt/trunk kamikaze
+$ svn checkout svn://svn.openwrt.org/openwrt/trunk kamikaze

 \end{Verbatim}
 
 \end{Verbatim}
 

-Additionally, ther is a trac interface on \href{https://dev.openwrt.org/}{https://dev.openwrt.org/}
-which can be used to monitor svn commits and browse the sources.
+Additionally, there is a trac interface on \href{https://dev.openwrt.org/}{https://dev.openwrt.org/}
+which can be used to monitor svn commits and browse the source repository.

 
 
 \subsubsection{The directory structure}
 
 
 \subsubsection{The directory structure}


@@ -65,25 +65,25 @@ There are four key directories in the base:
 
 \texttt{tools} and \texttt{toolchain} refer to common tools which will be
 used to build the firmware image, the compiler, and the C library.
 
 \texttt{tools} and \texttt{toolchain} refer to common tools which will be
 used to build the firmware image, the compiler, and the C library.

-The result of this is three new directories, \texttt{tool\_build}, which is a temporary
-directory for building the target independent tools, \texttt{toolchain\_build\_\textit{<arch>}}
+The result of this is three new directories, \texttt{build\_dir/host}, which is a temporary
+directory for building the target independent tools, \texttt{build\_dir/toolchain-\textit{<arch>}*}

 which is used for building the toolchain for a specific architecture, and
 which is used for building the toolchain for a specific architecture, and

-\texttt{staging\_dir\_\textit{<arch>}} where the resulting toolchain is installed.
+\texttt{staging\_dir/toolchain-\textit{<arch>}*} where the resulting toolchain is installed.

 You will not need to do anything with the toolchain directory unless you intend to
 add a new version of one of the components above.
 
 \begin{itemize}
 You will not need to do anything with the toolchain directory unless you intend to
 add a new version of one of the components above.
 
 \begin{itemize}

-    \item \texttt{tool\_build}
-    \item \texttt{toolchain\_build\_\textit{<arch>}}
+    \item \texttt{build\_dir/host}
+    \item \texttt{build\_dir/toolchain-\textit{<arch>}*}

 \end{itemize}
 
 \texttt{package} is for exactly that -- packages. In an OpenWrt firmware, almost everything
 is an \texttt{.ipk}, a software package which can be added to the firmware to provide new
 features or removed to save space. Note that packages are also maintained outside of the main
 \end{itemize}
 
 \texttt{package} is for exactly that -- packages. In an OpenWrt firmware, almost everything
 is an \texttt{.ipk}, a software package which can be added to the firmware to provide new
 features or removed to save space. Note that packages are also maintained outside of the main

-trunk and can be obtained from subversion at the following location:
+trunk and can be obtained from subversion using the package feeds system:

 
 \begin{Verbatim}
 
 \begin{Verbatim}

-$ svn co https://svn.openwrt.org/openwrt/packages ../packages
+$ ./scripts/feeds update

 \end{Verbatim}
 
 Those packages can be used to extend the functionality of the build system and need to be
 \end{Verbatim}
 
 Those packages can be used to extend the functionality of the build system and need to be


@@ -91,30 +91,31 @@ symlinked into the main trunk. Once you do that, the packages will show up in th
 configuration. From kamikaze you would do something like this:
 
 \begin{Verbatim}
 configuration. From kamikaze you would do something like this:
 
 \begin{Verbatim}

-$ ls
-kamikaze  packages
-$ ln -s packages/net/nmap kamikaze/package/nmap
+$ ./scripts/feeds search nmap
+Search results in feed 'packages':
+nmap       Network exploration and/or security auditing utility
+
+$ ./scripts/feeds install nmap

 \end{Verbatim}
 
 To include all packages, issue the following command:
 
 \begin{Verbatim}
 \end{Verbatim}
 
 To include all packages, issue the following command:
 
 \begin{Verbatim}

-$ ln -s packages/*/* kamikaze/package/
+$ make package/symlinks

 \end{Verbatim}
 
 \end{Verbatim}
 

-

 \texttt{target} refers to the embedded platform, this contains items which are specific to
 a specific embedded platform. Of particular interest here is the "\texttt{target/linux}"
 \texttt{target} refers to the embedded platform, this contains items which are specific to
 a specific embedded platform. Of particular interest here is the "\texttt{target/linux}"

-directory which is broken down by platform and contains the kernel config and patches
-to the kernel for a particular platform. There's also the "\texttt{target/image}" directory
+directory which is broken down by platform \textit{<arch>} and contains the patches to the
+kernel, profile config, for a particular platform. There's also the "\texttt{target/image}" directory

 which describes how to package a firmware for a specific platform.
 
 which describes how to package a firmware for a specific platform.
 

-Both the target and package steps will use the directory "\texttt{build\_\textit{<arch>}}"
+Both the target and package steps will use the directory "\texttt{build\_dir/\textit{<arch>}}"

 as a temporary directory for compiling. Additionally, anything downloaded by the toolchain,
 target or package steps will be placed in the "\texttt{dl}" directory.
 
 \begin{itemize}
 as a temporary directory for compiling. Additionally, anything downloaded by the toolchain,
 target or package steps will be placed in the "\texttt{dl}" directory.
 
 \begin{itemize}

-    \item \texttt{build\_\textit{<arch>}}
+    \item \texttt{build\_dir/\textit{<arch>}}

     \item \texttt{dl}
 \end{itemize}
 
     \item \texttt{dl}
 \end{itemize}
 


@@ -143,7 +144,15 @@ Similar to the linux kernel config, almost every option has three choices,
 \end{itemize}
 
 After you've finished with the menu configuration, exit and when prompted, save your
 \end{itemize}
 
 After you've finished with the menu configuration, exit and when prompted, save your

-configuration changes. To begin compiling the firmware, type "\texttt{make}". By default
+configuration changes.
+
+If you want, you can also modify the kernel config for the selected target system.
+simply run "\texttt{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 \texttt{target/linux/\textit{<platform>}/config} so that it is preserved over
+"\texttt{make clean}" calls.
+
+To begin compiling the firmware, type "\texttt{make}". By default

 OpenWrt will only display a high level overview of the compile process and not each individual
 command.
 
 OpenWrt will only display a high level overview of the compile process and not each individual
 command.
 


@@ -164,7 +173,7 @@ of noise caused by the compile output. To see the full output, run the command
 "\texttt{make V=99}".
 
 During the build process, buildroot will download all sources to the "\texttt{dl}"
 "\texttt{make V=99}".
 
 During the build process, buildroot will download all sources to the "\texttt{dl}"

-directory and will start patching and compiling them in the "\texttt{build\_\textit{<arch>}}"
+directory and will start patching and compiling them in the "\texttt{build\_dir/\textit{<arch>}}"

 directory. When finished, the resulting firmware will be in the "\texttt{bin}" directory
 and packages will be in the "\texttt{bin/packages}" directory.
 
 directory. When finished, the resulting firmware will be in the "\texttt{bin}" directory
 and packages will be in the "\texttt{bin/packages}" directory.
 


@@ -178,7 +187,7 @@ in OpenWrt you'll find two things:
 \begin{itemize}
     \item \texttt{package/\textit{<name>}/Makefile}
     \item \texttt{package/\textit{<name>}/patches}
 \begin{itemize}
     \item \texttt{package/\textit{<name>}/Makefile}
     \item \texttt{package/\textit{<name>}/patches}

-       \item \texttt{package/\textit{<name>}/files}
+    \item \texttt{package/\textit{<name>}/files}

 \end{itemize}
 
 The patches directory is optional and typically contains bug fixes or optimizations to
 \end{itemize}
 
 The patches directory is optional and typically contains bug fixes or optimizations to


@@ -195,13 +204,6 @@ simplifies the entire ordeal.
 Here for example, is \texttt{package/bridge/Makefile}:
 
 \begin{Verbatim}[frame=single,numbers=left]
 Here for example, is \texttt{package/bridge/Makefile}:
 
 \begin{Verbatim}[frame=single,numbers=left]

-#
-# Copyright (C) 2006 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
-# $Id: Makefile 5624 2006-11-23 00:29:07Z nbd $

 
 include $(TOPDIR)/rules.mk
 
 
 include $(TOPDIR)/rules.mk
 


@@ -222,12 +224,14 @@ define Package/bridge
   SECTION:=net
   CATEGORY:=Base system
   TITLE:=Ethernet bridging configuration utility
   SECTION:=net
   CATEGORY:=Base system
   TITLE:=Ethernet bridging configuration utility

-  DESCRIPTION:=\
-    Manage ethernet bridging: a way to connect networks together to \\\
-    form a larger network.

   URL:=http://bridge.sourceforge.net/
 endef
 
   URL:=http://bridge.sourceforge.net/
 endef
 

+define Package/bridge/description
+  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)" \
 define Build/Configure
     $(call Build/Configure/Default, \
         --with-linux-headers="$(LINUX_DIR)" \


@@ -289,7 +293,7 @@ directly as the Nth argument to \texttt{BuildPackage}.
 
     \begin{itemize}
         \item \texttt{SECTION} \\
 
     \begin{itemize}
         \item \texttt{SECTION} \\

-            The type of package (currently unused)
+            The section of package (currently unused)

         \item \texttt{CATEGORY} \\
             Which menu it appears in menuconfig: Network, Sound, Utilities, Multimedia ...
         \item \texttt{TITLE} \\
         \item \texttt{CATEGORY} \\
             Which menu it appears in menuconfig: Network, Sound, Utilities, Multimedia ...
         \item \texttt{TITLE} \\


@@ -299,7 +303,12 @@ directly as the Nth argument to \texttt{BuildPackage}.
         \item \texttt{MAINTAINER} (optional) \\
             Who to contact concerning the package
         \item \texttt{DEPENDS} (optional) \\
         \item \texttt{MAINTAINER} (optional) \\
             Who to contact concerning the package
         \item \texttt{DEPENDS} (optional) \\

-            Which packages must be built/installed before this package. To reference a dependency defined in the same Makefile, use \textit{<dependency name>}. If defined as an external package, use \textit{+<dependency name>}. For a kernel version dependency use: \textit{@LINUX\_2\_<minor version>}
+            Which packages must be built/installed before this package. To reference a dependency defined in the
+                       same Makefile, use \textit{<dependency name>}. If defined as an external package, use 
+                       \textit{+<dependency name>}. For a kernel version dependency use: \textit{@LINUX\_2\_<minor version>}
+               \item \texttt{BUILDONLY} (optional) \\
+                       Set this option to 1 if you do NOT want your package to appear in menuconfig.
+                       This is useful for packages which are only used as build dependencies.

     \end{itemize}
 
 \textbf{\texttt{Package/\textit{<name>}/conffiles} (optional):} \\
     \end{itemize}
 
 \textbf{\texttt{Package/\textit{<name>}/conffiles} (optional):} \\


@@ -313,10 +322,42 @@ directly as the Nth argument to \texttt{BuildPackage}.
    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
    "\texttt{\$(call Build/Configure/Default,\textit{<first list of arguments, second list>})}" as above to
    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
    "\texttt{\$(call Build/Configure/Default,\textit{<first list of arguments, second list>})}" as above to

-   pass in additional arguments for a standard configure script. The first list of arguments will be passed to the configure script like that: $--arg 1$ $--arg 2$. The second list contains arguments that should be defined before running the configure script such as autoconf or compiler specific variables.
+   pass in additional arguments for a standard configure script. The first list of arguments will be passed
+   to the configure script like that: \texttt{--arg 1} \texttt{--arg 2}. The second list contains arguments that should be
+   defined before running the configure script such as autoconf or compiler specific variables.
+   
+   To make it easier to modify the configure command line, you can either extend or completely override the following variables:
+   \begin{itemize}
+     \item \texttt{CONFIGURE\_ARGS} \\
+            Contains all command line arguments (format: \texttt{--arg 1} \texttt{--arg 2})
+     \item \texttt{CONFIGURE\_VARS} \\
+            Contains all environment variables that are passed to ./configure (format: \texttt{NAME="value"})
+   \end{itemize}

 
 \textbf{\texttt{Build/Compile} (optional):} \\
    How to compile the source; in most cases you should leave this undefined.
 
 \textbf{\texttt{Build/Compile} (optional):} \\
    How to compile the source; in most cases you should leave this undefined.

+   
+   As with \texttt{Build/Configure} there are two variables that allow you to override
+   the make command line environment variables and flags:
+   \begin{itemize}
+     \item \texttt{MAKE\_FLAGS} \\
+          Contains all command line arguments (typically variable overrides like \texttt{NAME="value"}
+        \item \texttt{MAKE\_VARS} \\
+          Contains all environment variables that are passed to the make command
+   \end{itemize}
+
+\textbf{\texttt{Build/InstallDev} (optional):} \\
+       If your package provides a library that needs to be made available to other packages,
+       you can use the \texttt{Build/InstallDev} template to copy it into the staging directory
+       which is used to collect all files that other packages might depend on at build time.
+       When it is called by the build system, two parameters are passed to it. \texttt{\$(1)} points to
+       the regular staging dir, typically \texttt{staging\_dir/\textit{ARCH}}, while \texttt{\$(2)} points
+       to \texttt{staging\_dir/host}. The host staging dir is only used for binaries, which are
+       to be executed or linked against on the host and its \texttt{bin/} subdirectory is included
+       in the \texttt{PATH} which is passed down to the build system processes.
+       Please use \texttt{\$(1)} and \texttt{\$(2)} here instead of the build system variables
+       \texttt{\$(STAGING\_DIR)} and \texttt{\$(STAGING\_DIR\_HOST)}, because the build system behavior
+       when staging libraries might change in the future to include automatic uninstallation.

 
 \textbf{\texttt{Package/\textit{<name>}/install}:} \\
    A set of commands to copy files out of the compiled source and into the ipkg
 
 \textbf{\texttt{Package/\textit{<name>}/install}:} \\
    A set of commands to copy files out of the compiled source and into the ipkg


@@ -345,6 +386,103 @@ After you have created your \texttt{package/\textit{<name>}/Makefile}, the new p
 will automatically show in the menu the next time you run "make menuconfig" and if selected
 will be built automatically the next time "\texttt{make}" is run.
 
 will automatically show in the menu the next time you run "make menuconfig" and if selected
 will be built automatically the next time "\texttt{make}" is run.
 

+\subsection{Creating binary packages}
+
+You might want to create binary packages and include them in the resulting images as packages.
+To do so, you can use the following template, which basically sets to nothing the Configure and
+Compile templates.
+
+\begin{Verbatim}[frame=single,numbers=left]
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=binpkg
+PKG_VERSION:=1.0
+PKG_RELEASE:=1
+
+PKG_SOURCE:=binpkg-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=http://server
+PKG_MD5SUM:=9b7dc52656f5cbec846a7ba3299f73bd
+PKG_CAT:=zcat
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/binpkg
+  SECTION:=net
+  CATEGORY:=Network
+  TITLE:=Binary package
+endef
+
+define Package/bridge/description
+  Binary package
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+endef
+
+define Package/bridge/install
+    $(INSTALL_DIR) $(1)/usr/sbin
+    $(INSTALL_BIN) $(PKG_BUILD_DIR)/* $(1)/usr/sbin/
+endef
+
+$(eval $(call BuildPackage,bridge))
+\end{Verbatim}
+
+Provided that the tarball which contains the binaries reflects the final
+directory layout (/usr, /lib ...), it becomes very easy to get your package
+look like one build from sources.
+
+Note that using the same technique, you can easily create binary pcakages
+for your proprietary kernel modules as well.
+
+\subsection{Creating kernel modules packages}
+
+The OpenWrt distribution makes the distinction between two kind of kernel modules, those coming along with the mainline kernel, and the others available as a separate project. We will see later that a common template is used for both of them.
+
+For kernel modules that are part of the mainline kernel source, the makefiles are located in \textit{package/kernel/modules/*.mk} and they appear under the section "Kernel modules"
+
+For external kernel modules, you can add them to the build system just like if they were software packages by defining a KernelPackage section in the package makefile.
+
+Here for instance the Makefile for the I2C subsytem kernel modules :
+
+\begin{Verbatim}[frame=single,numbers=left]
+
+I2CMENU:=I2C Bus
+
+define KernelPackage/i2c-core
+  TITLE:=I2C support
+  DESCRIPTION:=Kernel modules for i2c support
+  SUBMENU:=$(I2CMENU)
+  KCONFIG:=CONFIG_I2C_CORE CONFIG_I2C_DEV
+  FILES:=$(MODULES_DIR)/kernel/drivers/i2c/*.$(LINUX_KMOD_SUFFIX)
+  AUTOLOAD:=$(call AutoLoad,50,i2c-core i2c-dev)
+endef
+$(eval $(call KernelPackage,i2c-core))
+\end{Verbatim}
+
+To group kernel modules under a common description in menuconfig, you might want to define a \textit{<description>MENU} variable on top of the kernel modules makefile.
+
+\begin{itemize}
+    \item \texttt{TITLE} \\
+        The name of the module as seen via menuconfig
+    \item \texttt{DESCRIPTION} \\
+        The description as seen via help in menuconfig
+    \item \texttt{SUBMENU} \\
+        The sub menu under which this package will be seen
+    \item \texttt{KCONFIG} \\
+        Kernel configuration option dependency. For external modules, remove it.
+    \item \texttt{FILES} \\
+        Files you want to inlude to this kernel module package, separate with spaces.
+    \item \texttt{AUTOLOAD} \\
+        Modules that will be loaded automatically on boot, the order you write them is the order they would be loaded.
+\end{itemize}
+
+After you have created your \texttt{package/kernel/modules/\textit{<name>}.mk}, the new kernel modules package
+will automatically show in the menu under "Kernel modules" next time you run "make menuconfig" and if selected
+will be built automatically the next time "\texttt{make}" is run.

 
 \subsection{Conventions}
 
 
 \subsection{Conventions}
 


@@ -378,14 +516,14 @@ shortcuts you can take. Instead of waiting for make to get to your package, you
 run one of the following:
 
 \begin{itemize}
 run one of the following:
 
 \begin{itemize}

-    \item \texttt{make package/\textit{<name>}-clean V=99}
-    \item \texttt{make package/\textit{<name>}-install V=99}
+    \item \texttt{make package/\textit{<name>}/clean V=99}
+    \item \texttt{make package/\textit{<name>}/install V=99}

 \end{itemize}
 
 \end{itemize}
 

-Another nice trick is that if the source directory under \texttt{build\_\textit{<arch>}}
+Another nice trick is that if the source directory under \texttt{build\_dir/\textit{<arch>}}

 is newer than the package directory, it won't clobber it by unpacking the sources again.
 If you were working on a patch you could simply edit the sources under the
 is newer than the package directory, it won't clobber it by unpacking the sources again.
 If you were working on a patch you could simply edit the sources under the

-\texttt{build\_\textit{<arch>}/\textit{<source>}} directory and run the install command above,
+\texttt{build\_dir/\textit{<arch>}/\textit{<source>}} directory and run the install command above,

 when satisfied, copy the patched sources elsewhere and diff them with the unpatched
 sources. A warning though - if you go modify anything under \texttt{package/\textit{<name>}}
 it will remove the old sources and unpack a fresh copy.
 when satisfied, copy the patched sources elsewhere and diff them with the unpatched
 sources. A warning though - if you go modify anything under \texttt{package/\textit{<name>}}
 it will remove the old sources and unpack a fresh copy.


@@ -393,8 +531,65 @@ it will remove the old sources and unpack a fresh copy.
 Other useful targets include:
 
 \begin{itemize}
 Other useful targets include:
 
 \begin{itemize}

-    \item \texttt{make package/\textit{<name>}-prepare V=99}
-    \item \texttt{make package/\textit{<name>}-compile V=99}
-    \item \texttt{make package/\textit{<name>}-configure V=99}
+    \item \texttt{make package/\textit{<name>}/prepare V=99}
+    \item \texttt{make package/\textit{<name>}/compile V=99}
+    \item \texttt{make package/\textit{<name>}/configure V=99}

 \end{itemize}
 
 \end{itemize}
 

+
+\subsection{Using build environments}
+OpenWrt provides a means of building images for multiple configurations
+which can use multiple targets in one single checkout. These \emph{environments}
+store a copy of the .config file generated by \texttt{make menuconfig} and the contents
+of the \texttt{./files} folder.
+The script \texttt{./scripts/env} is used to manage these environments, it uses
+\texttt{git} (which needs to be installed on your system) as backend for version control.
+
+The command 
+\begin{Verbatim}
+  ./scripts/env help
+\end{Verbatim}
+produces a short help text with a list of commands.
+
+To create a new environment named \texttt{current}, run the following command
+\begin{Verbatim}
+  ./scripts/env new current
+\end{Verbatim}
+This will move your \texttt{.config} file and \texttt{./files} (if it exists) to
+the \texttt{env/} subdirectory and create symlinks in the base folder.
+
+After running make menuconfig or changing things in files/, your current state will
+differ from what has been saved before. To show these changes, use:
+\begin{Verbatim}
+  ./scripts/env diff
+\end{Verbatim}
+
+If you want to save these changes, run:
+\begin{Verbatim}
+  ./scripts/env save
+\end{Verbatim}
+If you want to revert your changes to the previously saved copy, run:
+\begin{Verbatim}
+  ./scripts/env revert
+\end{Verbatim}
+
+If you want, you can now create a second environment using the \texttt{new} command.
+It will ask you whether you want to make it a clone of the current environment (e.g.
+for minor changes) or if you want to start with a clean version (e.g. for selecting
+a new target).
+
+To switch to a different environment (e.g. \texttt{test1}), use:
+\begin{Verbatim}
+  ./scripts/env switch test1
+\end{Verbatim}
+
+To rename the current branch to a new name (e.g. \texttt{test2}), use:
+\begin{Verbatim}
+  ./scripts/env rename test2
+\end{Verbatim}
+
+If you want to get rid of environment switching and keep everything in the base directory
+again, use:
+\begin{Verbatim}
+  ./scripts/env clear
+\end{Verbatim}