The files in this directory are used to build the Debian installer. Basically it consists of downloading udebs, unpacking them, applying some magic (font reduction etc.) and building an image. Warning: The build system for the installer is often tightly bound to the version of Debian for which it is targeted. If you are using stable, use "apt-get source debian-installer" to get a version of the installer that will build on your system. If you are using testing or unstable, check out a copy of the installer using the command "git clone https://salsa.debian.org/installer-team/debian-installer.git" Recipe: - Install the build-dependencies on the host system (run dpkg-checkbuilddeps in the parent installer/ directory). - Create your own sources.list.udeb.local, otherwise the build host's sources.list is taken as a template for sources.list.udeb. - Run "make" to get a list of available targets. - Build an image using one of the build_ targets (build_netboot, all_build, etc). You may want to set the USE_UDEBS_FROM variable, documented below. - Look in dest/ for the completed images. Note that this does not create full debian ISO images; that is left to the debian-cd package. As a shortcut, you can create a mini-ISO image, with only the netboot initrd on it. make build_netboot will create a dest/netboot/mini.iso, using isolinux. Any size initrd can be placed on this ISO, which may be useful for testing. A more detailed overview of how the installer is built: * 'sources.list.udeb' is used to configure apt to download udebs from a mirror. It is autogenerated based on '/etc/apt/sources.list', by the Makefile's 'sources.list.udeb' target. Or you can provide your own locally modified 'sources.list.udeb.local'. You can also provide a 'preferences.udeb.local' to select specific versions of the packages (see apt_preferences(5) for its syntax). * The Makefile is configured via the make fragments in the config directory. These are organized in a subarch/medium/flavour hierarchy and get included by the main Makefile. * config/local can be added to override anything set in other fragments which are local to your system which you want to avoid accidentially committing. * 'pkg-lists' has subdirectories for the different image types that list udebs that are put on each image. The pkg-lists/*/common files list udebs common to all architectures, and the files named by architecture (.cfg) list udebs specific to an architecture. It is also possible to include udebs only on a specific subarchitecture by creating a directory for the architecture and putting config files for the subarchitecture there (/.cfg). All of these files can have #include lines to include files from pkg-lists. Also, ${kernel:Version} in these files is replaced with the kernel version, as set in the KERNELVERSION variable (plus the KERNEL_FLAVOUR variable). * Anything listed in pkg-lists/local and pkg-lists/*/local is included in the image that is built. This is to provide an easy way to add extra udebs to a test image. * All dependencies of packages in pkg-lists are automatically included in an image by default. If you know that some of the dependencies are wrong, or do not apply to an image, you can remove dependencies from the pkg-lists by listing them and putting a space and minus sign after them. * If you need to include a package for one major version of a kernel, but not for another, put the kernel major version(s) that should have the package in brackets at the end of the line. For example: discover1 [2.2 2.4] * Similarly, if you need to include a package for only one type of kernel, put the name of the kernel(s) that should have the package in brackets at the end of the line. For example: gnumach-udeb [hurd] * If you'd like to include a given package only if it's available, and not fail otherwise, put a question mark at the end of the line. For example: pcmcia-modules-${kernel:Version} ? It's recommended to use this option seldom and with care as it can make the build less robust if packages can be dropped from it without warning. * Apt is used to download the required udebs. This does *not* include libraries; libraries used by udebs must be installed on the build system, and so are build-depended on. * If you have some udebs that are not available on your mirror yet, you can drop them in 'localudebs/' and they will be used. * dpkg is used to unpack the udebs into the build directory. * Some boot images have associated "driver" disks. These disks just get udebs put on them. * The final images are put in the dest/ directory. ------------ The debian-installer build system --------------------------------- The build system is designed to allow the addition of configurations with minimal effort. It achieves this by evaluating some magic variables from the configuration snippet and feeding some generic rules you hopefully never need to know about. The configuration snippets live in the config/ directory and are organized in a hierarchical tree structure, the directory names therein have also a specific meaning. It follows a config/$ARCH/$SUBARCH/$MEDIUM/$FLAVOUR scheme, where $ARCH is mandatorily the debian architecture name. For the other three, the requirement is you need to use at least one. $SUBARCH is supposed to be the subarchitecture. For e.g. m68k this would be something like "amiga" or "atari", i386 doesn't use it. $MEDIUM is the boot medium, like "cdrom", "floppy", "netboot". $FLAVOUR distinguishes between other differences, like 2.4 vs. 2.6 kernels, or several floppy images. Note: You don't have to follow this usage strictly, the variable naming is merely a hint. It could also have been named as $LEVEL1/$LEVEL2/LEVEL3. Note2: The resulting file tree in the dest/ directory has a similiar $SUBARCH/$MEDIUM/$FLAVOUR layout. It can be slightly adapted with the EXTRANAME and SOME_DEST variables. An example tree layout looks like this: config |-- i386 | |-- cdrom | | |-- el-torito-2.6.cfg | | |-- el-torito.cfg | | |-- isolinux-2.6.cfg | | `-- isolinux.cfg | |-- cdrom.cfg | |-- floppy | | |-- boot.cfg | | |-- cd-drivers.cfg | | `-- root.cfg | |-- floppy.cfg | |-- hd-media | | `-- 2.6.cfg | |-- hd-media.cfg | |-- monolithic | | `-- 2.6.cfg | |-- monolithic.cfg | |-- netboot | | `-- 2.6.cfg | `-- netboot.cfg `-- i386.cfg In the first level, you have an $ARCH directory, and an $ARCH.cfg configuration snippet, which needs to define what to use from the tree below, and can also define commonly used variables for all configurations of this architecture. An example $ARCH.cfg would look like this: SUBARCH_SUPPORTED = r4k-ip22 r5k-ip22 sb1-bcm91250a miniiso KERNELMAJOR = 2.4 KERNELMINOR = 25 KERNEL_FLAVOUR = di KERNELNAME = $(foreach ver,$(KERNELVERSION),vmlinux-$(ver)) VERSIONED_SYSTEM_MAP = t arch_boot_screens: The SUBARCH_SUPPORTED line defines what to look up in the next directory level. In this case, these are the configuration snippets r4k-ip22.cfg, r5k-ip22.cfg, sb1-bcm91250a.cfg and miniiso.cfg. Each of those snippets can define a MEDIUM_SUPPORTED variable, which opens the next subdirectory level. Those subdirectories have to have the name of their subarchitecture, for the example above e.g. r4k-ip22 or sb1-bcm91250a. The various KERNEL* variables are common for all configurations of this architecture, so they were moved upwards from the leaf configuration snippets. The same can be done for make rules. Caveats: - You can re-/undefine variables defined in a higher level, but you can't do that for rules. Make will complain about it. - Use always recursively expanded variables (that is '=', not ':='). Make works though the tree by recursively calling itself. If you use simply expanded variables, the variables of higher levels (like *_SUPPORTED) won't get re-evaluated, and things will break. Interesting Variables in configuration snippets ----------------------------------------------- First, mandatory variables: SUBARCH_SUPPORTED MEDIUM_SUPPORTED FLAVOUR_SUPPORTED As already explained, they define what configurations the build system should look for. They cause the definition of SUBARCH, MEDIUM and FLAVOUR for every snippet they invoke that way. At least one of them must be defined. KERNELMAJOR The high part of the kernel version, like "2.6". Unluckily, this is what the kernel people call MAJOR.MINOR. KERNELVERSION The version of the kernel .udeb package, like "2.4.26-r4k-ip22" KERNELNAME The full name of the kernel image. If you build an EXTRA target (e.g. for a driver floppy), this variable has to be empty. TYPE This variable points to the subdirectory in pkg-lists/ which should be used for this config. E.g. $TYPE=cdrom means that pkg-lists/cdrom/local, pkg-lists/cdrom/common and pkg-lists/cdrom/ are used. Defaults to $(MEDIUM)/. Targets: TARGET Define this variable in the leaf configuration snippet to one or more of the following generic targets, and any local target you want to run. INITRD Create an gzipped initrd.gz. KERNEL Create the kernel image. BOOT Create an optionally gzipped bootable image. This creates kernel, initrd and boot screens, and depends on the arch_boot rule, where the image creation is handled. ROOT Create an optionally gzipped root image. This creates an initrd and depends on the arch_root rule, where the image creation is handled. EXTRA This creates a file system image with driver .udebs in it. MINIISO This creates a mini ISO image, by creating the boot screens and depending on arch_miniiso rule, where the image creation is handled. DEBIAN_CD_INFO This provides the boot screens in a gzipped tarball. MISC This copies files to the destination directory of your configuration. MANIFEST-INITRD MANIFEST-KERNEL MANIFEST-BOOT MANIFEST-ROOT MANIFEST-EXTRA MANIFEST-MINIISO MANIFEST-DEBIAN_CD_INFO MANIFEST-MISC These variables correspond to the generic targets and hold their description which is added to the MANIFEST file in the dest/ directory. TEMP_INITRD TEMP_UDEB_LIST TEMP_KERNEL TEMP_BOOT TEMP_ROOT TEMP_MINIISO TEMP_EXTRA TEMP_BOOT_SCREENS TEMP_CD_TREE TEMP_POWERPC_INITRD Those are intermediate targets. Everything is built for them, the generic targets copy the stuff they are interested in over to the dest/ and add the MANIFEST entry. They are useful as dependencies for things which needs to be built but shouldn't show up in the destination directory. You should never need to redefine them. Other useful variables for configuration snippets: LINUX_KERNEL_ABI The first part of the kernel version, e.g. 3.14-2. Used as the default base/suffix for KERNELVERSION (i.e. $(LINUX_KERNEL_ABI)-amd64). KERNEL_FLAVOUR The flavour of the kernel .udeb package. This has nothing to do with FLAVOUR. It has always a value of "di" these days. SUBARCH_SUPPORTED_EXTRA MEDIUM_SUPPORTED_EXTRA FLAVOUR_SUPPORTED_EXTRA These are like SUBARCH_SUPPORTED (etc.), except that they are not built by default with 'make all_build' but are only used when selected manually, either by passing an explicit target to make or by defining RECURSE_EXTRA to a non-empty value. EXTRANAME This allows to vary the name of the dest/ target a bit. Example: EXTRANAME = $(MEDIUM)/ leads to: floppy/netboot.img EXTRANAME = $(MEDIUM)- leads to: floppy-netboot.img Nice to avoid subdirectories with only a single file in it. DEST The destination directory of your configuration. Caveat: Always use $(DEST), not ./dest/foo/... The latter will only work for one specific location, and fails if you relocate the configuration snippet in the tree. DEST changes its definition for every leaf configuration appropriately. SOME_DEST Like DEST, but with the last path element removed. Mostly useful in combination with EXTRANAME. TEMP The intermediate directory, where everything is built. Caveat: Always build stuff in TEMP, and then install to DEST from there. Doing this differently tends to turn into a mess. Caveat2: Always use $(TEMP), not ./tmp/foo/... The latter will only work for one specific leaf configuration. TEMP changes its definition for every leaf configuration appropriately. DROP_LANG Purge unwanted languages. Mostly useful for space constrained media. KEEP_GI_LANGS If set the languages in $(GI_LANGS) will NOT be dropped. Should only be set in targets building graphical installer images. GI_LANGS List of languages only supported with the graphical cdebconf frontend. VERSIONED_SYSTEM_MAP If set, the kernel's System.map is expected to have an unique filename for each kernel of this architecture. FLOPPY_SIZE The size of a floppy image, in kilobytes. IMAGE_SIZE The size of a an image, in kilobytes. Only needed and supported for some types of images. DISK_LABEL Disk label to use when formating disk images. Allowed content varies by disk type. MEDIA_TYPE The type of media produced, currently used to make qemu boot the image properly. Suggested values: "CD-ROM", "netboot image", "floppy", etc. DEBIAN_RELEASE The codename of the debian release to be installed by default. Included in /etc/default-release in most initrds. DEBIAN_VERSION The version identification (number + codename) of the Debian release. USE_UDEBS_FROM Normally the codename of the release to use for the build. Defaults to unstable for daily builds. Set from debian/rules when building through dpkg-buildpackage. Included in /etc/udebs-source in most initrds. USE_PROPOSED_UPDATES Set to 1 in debian/rules to have the gen-sources.list.udeb script include udebs from $USE_UDEBS_FROM-proposed-updates (for official builds of e.g. stable updates). For manual builds use for example: make USE_PROPOSED_UPDATES=1 all_build If no valid source for proposed updates is found, the build will fail. OMIT_RELEASE_INFO Can be used to suppress the inclusion of the files /etc/default-release and /etc/udebs-source in some targets (like boot floppies). DOS_VOLUME_ID DOS_VOLUME_LABEL Volume ID and label for DOS filesystems. SYSLINUX_CFG (x86 only) Determines how the syslinux configuration is created. Options are: - prompt: non-graphical syslinux configuration allowing installation of only a default desktop environment - standard: as prompt, but graphical menu (using vesamenu) - template: the available files are merely copied; the actual configuration is created by debian-cd BOOTMENU_BEEP Set to y to produce a beep when the boot menu is ready to accept commands (e.g. extra kernel parameters, etc.) This improves accessibility of the image for blind people. GZIPPED Create gzipped images. This works only for the BOOT, ROOT and EXTRA targets. EXTRADRIVERS This variable points to the directories where additional driver .udebs reside. This causes these .udebs to be considered in the font reduction step, so the characters needed for them are kept. EXTRATARGETS Additional targets which are run before the ones in TARGET. This is e.g. useful to build the additional driver images first, and then use their intermediate tree for EXTRADRIVERS. EXTRAUDEBS This variable points to additional udebs that should be considered by the font reduction step. DRIVER_FOR The variable indicates that the image is just a driver image for some other image. The value points to the directory in pkg-lists for the image that it's a driver for. UPX If this variable is set, it should point to a usable UPX compressor. This is then used to create UPX compressed kernels. SYSLINUX_OPTS Additional syslinux options. SPLASH_RLE SPLASH_PNG The syslinux splash screen file. INITRD_FS The filesystem to use for initrds, needs to be built into the kernel. ext2, initramfs, or jffs2. MKFS_JFFS2 If using jffs2 for the INITRD_FS, you will need to set this variable to a command to use to create the image. For example: MKFS_JFFS2 = mkfs.jffs2 -f -p -b -e 0x20000 WRITE_MEDIA Add you configuration's name if it can be written to a raw device. Mostly useful for floppies. UDEB_LISTS List of files listing udebs that were used to build the image. TRANSSTATUS Location of file with translation statistics. This file is intended to be included only for official releases and thus this variable is set in debian/rules. The file is only included if it exists. A warning will be displayed if the file is older than 2 weeks than the time of the build. If needed, inclusion of the file can be prevented by setting the variable to empty for specific targets (e.g. most floppy images) in config or globally in config/common. Variables useful for testing: FLOPPYDEV The device name to use for writing a image to a raw device. QEMU The name of the qemu emulator binary. EXTRAS Add additional .udebs to the target image. EXTRAFILES Add additional files to the target image. SSL_CERTS Add SSL certificates to the target image. For this to be useful, you will also need to supply d-i with GNU wget. MIRROR The mirror to get .deb and .udeb packages from. Defaults to the same as the host machine uses. UDEB_COMPONENTS Archive components from which to fetch .udeb packages. Defaults to main/debian-installer. PRESEED An initrd preseed file to put in the initrd. Rules invoked from the various targets: arch_boot: The bootable image TEMP_BOOT is created in this rule, usually from TEMP_KERNEL and TEMP_INITRD, and probably from TEMP_BOOT_SCREENS and other files. arch_root: The root image TEMP_ROOT is created in this rule, usually from TEMP_INITRD, and probably some other files. arch_boot_screens: The boot screens in TEMP_BOOT_SCREENS are created here. arch_miniiso: The mini ISO image TEMP_MINIISO is built here, from whatever the particular (sub-)architecture needs for it.