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CRUNCHGEN(1)		  BSD General Commands Manual		  CRUNCHGEN(1)

NAME
     crunchgen — generates build environment for a crunched binary

SYNOPSIS
     crunchgen [-foql] [-h makefile-header-name] [-m makefile-name]
	       [-p obj-prefix] [-c c-file-name] [-e exec-file-name]
	       [conf-file]

DESCRIPTION
     A crunched binary is a program made up of many other programs linked
     together into a single executable.	 The crunched binary main() function
     determines which component program to run by the contents of argv[0].
     The main reason to crunch programs together is for fitting as many pro‐
     grams as possible onto an installation or system recovery floppy.

     The crunchgen utility reads in the specifications in conf-file for a
     crunched binary, and generates a Makefile and accompanying top-level C
     source file that when built creates the crunched executable file from the
     component programs.  For each component program, crunchgen can optionally
     attempt to determine the object (.o) files that make up the program from
     its source directory Makefile.  This information is cached between runs.
     The crunchgen utility uses the companion program crunchide(1) to elimi‐
     nate link-time conflicts between the component programs by hiding all
     unnecessary symbols.

     The crunchgen utility places specific requirements on package Makefiles
     which make it unsuitable for use with non-BSD sources.  In particular,
     the Makefile must contain the target depend, and it must define all
     object files in the variable OBJS.	 In some cases, you can use a fake
     Makefile: before looking for Makefile in the source directory foo,
     crunchgen looks for the file Makefile.foo in the current directory.

     After crunchgen is run, the crunched binary can be built by running “make
     -f <conf-name>.mk”.  The component programs' object files must already be
     built.  An objs target, included in the output makefile, will run make(1)
     in each component program's source dir to build the object files for the
     user.  This is not done automatically since in release engineering cir‐
     cumstances it is generally not desirable to be modifying objects in other
     directories.

     The options are as follows:

     -c c-file-name
	     Set output C file name to c-file-name.  The default name is
	     <conf-name>.c.

     -e exec-file-name
	     Set crunched binary executable file name to exec-file-name.  The
	     default name is <conf-name>.

     -f	     Flush cache.  Forces the recalculation of cached parameters.

     -l	     List names.  Lists the names this binary will respond to.

     -h makefile-header-name
	     Set the name of a file to be included at the beginning of the
	     Makefiles generated by crunchgen.	This is useful to define some
	     make variables such as RELEASE_CRUNCH or similar, which might
	     affect the behavior of make(1) and are annoying to pass through
	     environment variables.

     -m makefile-name
	     Set output Makefile name to makefile-name.	 The default name is
	     <conf-name>.mk.

     -o	     Add “make obj” rules to each program make target.

     -p obj-prefix
	     Set the pathname to be prepended to the srcdir when computing the
	     objdir.  If this option is not present, then the prefix used is
	     the content of the MAKEOBJDIRPREFIX environment variable, or
	     /usr/obj.

     -q	     Quiet operation.  Status messages are suppressed.

CRUNCHGEN CONFIGURATION FILE COMMANDS
     The crunchgen utility reads specifications from the conf-file that
     describe the components of the crunched binary.  In its simplest use, the
     component program names are merely listed along with the top-level source
     directories in which their sources can be found.  The crunchgen utility
     then calculates (via the source makefiles) and caches the list of object
     files and their locations.	 For more specialized situations, the user can
     specify by hand all the parameters that crunchgen needs.

     The conf-file commands are as follows:

     srcdirs dirname ...
	     A list of source trees in which the source directories of the
	     component programs can be found.  These dirs are searched using
	     the BSD “<source-dir>/<progname>/” convention.  Multiple srcdirs
	     lines can be specified.  The directories are searched in the
	     order they are given.

     progs progname ...
	     A list of programs that make up the crunched binary.  Multiple
	     progs lines can be specified.

     libs libspec ...
	     A list of library specifications to be included in the crunched
	     binary link.  Multiple libs lines can be specified.

     libs_so libspec ...
	     A list of library specifications to be dynamically linked in the
	     crunched binary.  These libraries will need to be made available
	     via the run-time link-editor rtld(1) when the component program
	     that requires them is executed from the crunched binary.  Multi‐
	     ple libs_so lines can be specified.  The libs_so directive over‐
	     rides a library specified gratuitously on a libs line.

     buildopts buildopts ...
	     A list of build options to be added to every make target.

     ln progname linkname
	     Causes the crunched binary to invoke progname whenever linkname
	     appears in argv[0].  This allows programs that change their
	     behavior when run under different names to operate correctly.

     To handle specialized situations, such as when the source is not avail‐
     able or not built via a conventional Makefile, the following special com‐
     mands can be used to set crunchgen parameters for a component program.

     special progname srcdir pathname
	     Set the source directory for progname.  This is normally calcu‐
	     lated by searching the specified srcdirs for a directory named
	     progname.

     special progname objdir pathname
	     Set the obj directory for progname.  The obj directory is nor‐
	     mally calculated by looking for a directory whose name is that of
	     the source directory prepended by one of the following compo‐
	     nents, in order of priority: the -p argument passed to the com‐
	     mand line; or, the value of the MAKEOBJDIRPREFIX environment
	     variable, or /usr/obj.  If the directory is not found, the srcdir
	     itself becomes the objdir.

     special progname buildopts buildopts
	     Define a set of build options that should be added to make(1)
	     targets in addition to those specified using buildopts when pro‐
	     cessing progname.

     special progname objs object-file-name ...
	     Set the list of object files for program progname.	 This is nor‐
	     mally calculated by constructing a temporary makefile that
	     includes “srcdir/Makefile” and outputs the value of $(OBJS).

     special progname objpaths full-pathname-to-object-file ...
	     Sets the pathnames of the object files for program progname.
	     This is normally calculated by prepending the objdir pathname to
	     each file in the objs list.

     special progname objvar variable_name
	     Sets the name of the make(1) variable which holds the list of
	     object files for program progname.	 This is normally OBJS but
	     some Makefiles might like to use other conventions or prepend the
	     program's name to the variable, e.g. SSHD_OBJS.

     special progname lib library-name ...
	     Specifies libraries to be linked with object files to produce
	     progname.lo.  This can be useful with libraries which redefine
	     routines in the standard libraries, or poorly written libraries
	     which reference symbols in the object files.

     special progname keep symbol-name ...
	     Add specified list of symbols to the keep list for program
	     progname.	An underscore (‘_’) is prepended to each symbol and it
	     becomes the argument to a -k option for the crunchide(1) phase.
	     This option is to be used as a last resort as its use can cause a
	     symbol conflict, however in certain instances it may be the only
	     way to have a symbol resolve.

     special progname ident identifier
	     Set the Makefile/C identifier for progname.  This is normally
	     generated from a progname, mapping ‘-’ to ‘_’ and ignoring all
	     other non-identifier characters.  This leads to programs named
	     "foo.bar" and "foobar" to map to the same identifier.

     Only the objpaths parameter is actually needed by crunchgen, but it is
     calculated from objdir and objs, which are in turn calculated from
     srcdir, so is sometimes convenient to specify the earlier parameters and
     let crunchgen calculate forward from there if it can.

     The makefile produced by crunchgen contains an optional objs target that
     will build the object files for each component program by running make(1)
     inside that program's source directory.  For this to work the srcdir and
     objs parameters must also be valid.  If they are not valid for a particu‐
     lar program, that program is skipped in the objs target.

EXAMPLES
     Here is an example crunchgen input conf file, named “kcopy.conf”:

	   srcdirs /usr/src/bin /usr/src/sbin

	   progs test cp echo sh fsck halt init mount umount myinstall
	   progs anotherprog
	   ln test [	   # test can be invoked via [
	   ln sh -sh	   # init invokes the shell with "-sh" in argv[0]

	   special myprog objpaths /homes/leroy/src/myinstall.o # no sources

	   special anotherprog -DNO_FOO WITHOUT_BAR=YES

	   libs -lutil -lcrypt

     This conf file specifies a small crunched binary consisting of some basic
     system utilities plus a homegrown install program “myinstall”, for which
     no source directory is specified, but its object file is specified
     directly with the special line.

     Additionally when “anotherprog” is built the arguments

	   -DNO_FOO WITHOUT_BAR=YES

     are added to all build targets.

     The crunched binary “kcopy” can be built as follows:

	   % crunchgen -m Makefile kcopy.conf	 # gen Makefile and kcopy.c
	   % make objs		   # build the component programs' .o files
	   % make		   # build the crunched binary kcopy
	   % kcopy sh		   # test that this invokes a sh shell
	   $			   # it works!

     At this point the binary “kcopy” can be copied onto an install floppy and
     hard-linked to the names of the component programs.

     Note that if the libs_so command had been used, copies of the libraries
     so named would also need to be copied to the install floppy.

SEE ALSO
     crunchide(1), make(1), rtld(1)

CAVEATS
     While crunchgen takes care to eliminate link conflicts between the compo‐
     nent programs of a crunched binary, conflicts are still possible between
     the libraries that are linked in.	Some shuffling in the order of
     libraries may be required, and in some rare cases two libraries may have
     an unresolvable conflict and thus cannot be crunched together.

     Some versions of the BSD build environment do not by default build the
     intermediate object file for single-source file programs.	The “make
     objs” must then be used to get those object files built, or some other
     arrangements made.

AUTHORS
     The crunchgen utility was written by James da Silva ⟨jds@cs.umd.edu⟩.

     Copyright (c) 1994 University of Maryland.	 All Rights Reserved.

     The libs_so keyword was added in 2005 by Adrian Steinmann ⟨ast@marabu.ch⟩
     and Ceri Davies ⟨ceri@FreeBSD.org⟩.

BSD			       December 23, 2005			   BSD
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