Table of contents: A. How to build XNU B. How to install a new header file from XNU ============================================= A. How to build XNU: 1) Type: "make" This builds all the components for kernel, architecture, and machine configurations defined in TARGET_CONFIGS. Additionally, we also support architectures defined in ARCH_CONFIGS and kernel configurations defined in KERNEL_CONFIGS. Note that TARGET_CONFIGS overrides any configurations defined in ARCH_CONFIGS and KERNEL_CONFIGS. By default, architecture defaults to the build machine architecture, and the kernel configuration is set to build for DEVELOPMENT. This will also create a bootable image, mach_kernel, and a kernel binary with symbols, mach_kernel.sys. /* this is all you need to do to build with RELEASE kernel configuration */ make TARGET_CONFIGS="release x86_64 default" SDKROOT=/path/to/SDK or the following is equivalent (ommitted SDKROOT will use /) make ARCH_CONFIGS=X86_64 2) Building DEBUG Define kernel configuration to DEBUG in your environment or when running a make command. Then, apply procedures 4, 5 $ make TARGET_CONFIGS="DEBUG X86_64 DEFAULT" all or $ make KERNEL_CONFIGS=DEBUG ARCH_CONFIGS=X86_64 all or $ export TARGET_CONFIGS="DEBUG X86_64 DEFAULT" $ export SDKROOT=/path/to/SDK $ make all Example: $(OBJROOT)/DEBUG_X86_64/osfmk/DEBUG/osfmk.filelist: list of objects in osfmk component $(OBJROOT)/DEBUG_X86_64/mach_kernel: bootable image 3) Building fat Define architectures in your environment or when running a make command. Apply procedures 3, 4, 5 $ make TARGET_CONFIGS="RELEASE I386 DEFAULT RELEASE X86_64 DEFAULT" exporthdrs all or $ make ARCH_CONFIGS="I386 X86_64" exporthdrs all or $ export ARCH_CONFIGS="I386 X86_64" $ make exporthdrs all 4) Verbose make To display complete tool invocations rather than an abbreviated version, $ make VERBOSE=YES 5) Debug information formats By default, a DWARF debug information repository is created during the install phase; this is a "bundle" named mach_kernel.dSYM To select the older STABS debug information format (where debug information is embedded in the mach_kernel.sys image), set the BUILD_STABS environment variable. $ export BUILD_STABS=1 $ make 6) Build check before integration From the top directory, run: $ ~rc/bin/buildit . -arch i386 -arch x86_64 -arch armv7 -arch ppc -noinstallsrc -nosum xnu supports a number of XBS build aliases, which allow B&I to build the same source submission multiple times in different ways, to produce different results. Each build alias supports the standard "clean", "install", "installsrc", "installhdrs" targets, but conditionalize their behavior on the RC_ProjectName make variable which is passed as the -project argument to ~rc/bin/buildit, which can be one of: -project xnu # the default, builds /mach_kernel, kernel-space # headers, user-space headers, man pages, # symbol-set kexts -project xnu_debug # a DEBUG kernel in /AppleInternal with dSYM -project libkxld # user-space version of kernel linker -project libkmod # static library automatically linked into kexts -project Libsyscall # automatically generate BSD syscall stubs -project xnu_quick_test # install xnu unit tests 7) Creating tags and cscope Set up your build environment as per instructions in 2a From the top directory, run: $ make tags # this will build ctags and etags on a case-sensitive # volume, only ctags on case-insensitive $ make TAGS # this will build etags $ make cscope # this will build cscope database 8) Other makefile options $ make MAKEJOBS=-j8 # this will use 8 processes during the build. The default is 2x the number of active CPUS. $ make -j8 # the standard command-line option is also accepted $ make -w # trace recursive make invocations. Useful in combination with VERBOSE=YES $ make BUILD_LTO=1 # build with LLVM Link Time Optimization (experimental) $ make REMOTEBUILD=user@remotehost # perform build on remote host ============================================= B. How to install a new header file from XNU [Note: This does not cover installing header files in IOKit framework] 1) XNU installs header files at the following locations - a. $(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers b. $(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders c. $(DSTROOT)/System/Library/Frameworks/System.framework/Headers d. $(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders e. $(DSTROOT)/usr/include/ Kernel.framework is used by kernel extensions. System.framework and /usr/include are used by user level applications. The header files in framework's "PrivateHeaders" are only available for Apple Internal development. 2) The directory containing the header file should have a Makefile that creates the list of files that should be installed at different locations. If you are adding first header file in a directory, you will need to create Makefile similar to xnu/bsd/sys/Makefile. Add your header file to the correct file list depending on where you want to install it. The default locations where the header files are installed from each file list are - a. DATAFILES : To make header file available in user level - $(DSTROOT)/System/Library/Frameworks/System.framework/Headers $(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders $(DSTROOT)/usr/include/ b. PRIVATE_DATAFILES : To make header file available to Apple internal in user level - $(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders c. KERNELFILES : To make header file available in kernel level - $(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers $(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders d. PRIVATE_KERNELFILES : To make header file available to Apple internal for kernel extensions - $(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders 3) The Makefile combines the file lists mentioned above into different install lists which are used by build system to install the header files. If the install list that you are interested does not exist, create it by adding the appropriate file lists. The default install lists, its member file lists and their default location are described below - a. INSTALL_MI_LIST : Installs header file to location that is available to everyone in user level. Locations - $(DSTROOT)/System/Library/Frameworks/System.framework/Headers $(DSTROOT)/usr/include/ Definition - INSTALL_MI_LIST = ${DATAFILES} b. INSTALL_MI_LCL_LIST : Installs header file to location that is available for Apple internal in user level. Locations - $(DSTROOT)/System/Library/Frameworks/System.framework/PrivateHeaders Definition - INSTALL_MI_LCL_LIST = ${DATAFILES} ${PRIVATE_DATAFILES} c. INSTALL_KF_MI_LIST : Installs header file to location that is available to everyone for kernel extensions. Locations - $(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers Definition - INSTALL_KF_MI_LIST = ${KERNELFILES} d. INSTALL_KF_MI_LCL_LIST : Installs header file to location that is available for Apple internal for kernel extensions. Locations - $(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders Definition - INSTALL_KF_MI_LCL_LIST = ${KERNELFILES} ${PRIVATE_KERNELFILES} 4) If you want to install the header file in a sub-directory of the paths described in (1), specify the directory name using two variable INSTALL_MI_DIR and EXPORT_MI_DIR as follows - INSTALL_MI_DIR = dirname EXPORT_MI_DIR = dirname 5) A single header file can exist at different locations using the steps mentioned above. However it might not be desirable to make all the code in the header file available at all the locations. For example, you want to export a function only to kernel level but not user level. You can use C language's pre-processor directive (#ifdef, #endif, #ifndef) to control the text generated before a header file is installed. The kernel only includes the code if the conditional macro is TRUE and strips out code for FALSE conditions from the header file. Some pre-defined macros and their descriptions are - a. PRIVATE : If true, code is available to all of the xnu kernel and is not available in kernel extensions and user level header files. The header files installed in all the paths described above in (1) will not have code enclosed within this macro. b. KERNEL_PRIVATE : Same as PRIVATE c. BSD_KERNEL_PRIVATE : If true, code is available to the xnu/bsd part of the kernel and is not available to rest of the kernel, kernel extensions and user level header files. The header files installed in all the paths described above in (1) will not have code enclosed within this macro. d. KERNEL : If true, code is available only in kernel and kernel extensions and is not available in user level header files. Only the header files installed in following paths will have the code - $(DSTROOT)/System/Library/Frameworks/Kernel.framework/Headers $(DSTROOT)/System/Library/Frameworks/Kernel.framework/PrivateHeaders