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

NAME
     crunchgen -- generates build environment for a crunched binary

SYNOPSIS
     crunchgen [-fOoq] [-c c-file-name] [-D src-root] [-d build-options] [-e exec-file-name]
	       [-L lib-dir] [-m makefile-name] [-v var-spec] 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 programs as possible onto an installation or system recovery floppy.

     crunchgen 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 create the crunched exe-
     cutable file from the component programs.	For each component program, crunchgen can option-
     ally attempt to determine the object (.o) files that make up the program from its source
     directory Makefile.  This information is cached between runs.  crunchgen uses the companion
     program crunchide to eliminate link-time conflicts between the component programs by hiding
     all unnecessary symbols.

     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 in each component program's source
     dir to build the object files for the user.  This is not done automatically since in release
     engineering circumstances 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 ``<confname>.c''.

     -D src-root
	     Assume that relative source directory specifications begin with src-root.

     -d build-options
	     Set the DBG variable in the generated makefile to build-options.  The default flags
	     are -Os.

     -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 lib-dir
	     Try to obtain libraries from lib-dir.

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

     -O      Force crunchgen to parse the program's Makefile in determine the list of .o files.
	     Without this option crunchgen expects the program's Makefile to have a program.ro
	     target that links all the program objects into a single relocatable.

     -o      Use existing object files.  Rather than rebuilding object files via reach-over make-
	     files, instead search for and use existing object files.

     -q      Quiet operation.  Status messages are suppressed.

     -v varspec
	     Append a variable specification to the on-the fly generated Makefile.

CRUNCHGEN CONFIGURATION FILE COMMANDS
     crunchgen 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.  crunchgen then
     calculates (via the source makefiles) and caches the list of object files and their loca-
     tions.  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>/'' con-
	     vention.  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.  Multi-
	     ple libs lines can be specified.

     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 available or not built via
     a conventional Makefile, the following special commands can be used to set crunchgen parame-
     ters for a component program.

     special progname keepsymbols symbols ...
	     Don't hide the specified symbols for progname.  Normally all externally visible sym-
	     bols for a program is hidden to avoid interference.  Multiple keepsymbols lines can
	     be specified for given progname.

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

     special progname objdir pathname
	     Set the obj directory for progname.  This is normally calculated by looking for a
	     directory named ``obj'' under the srcdir, and if that is not found, the srcdir
	     itself becomes the objdir.

	     Note: This option only takes effect if the -o option to use existing object files is
	     also specified.

     special progname objs object-file-name ...
	     Set the list of object files for program progname.  This is normally calculated by
	     constructing a temporary makefile that includes ``srcdir / Makefile'' and outputs
	     the value of $(OBJS).  Multiple objs lines can be specified for given progname.

     special progname objpaths full-pathname-to-object-file ...
	     Sets the pathnames of the object files for program progname.  This is normally cal-
	     culated by prepending the objdir pathname to each file in the objs list.  Multiple
	     objpaths lines can be specified for given progname.

     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 inside that program's source direc-
     tory.  For this to work the srcdir and objs parameters must also be valid.  If they are not
     valid for a particular program, that program is skipped in the objs target.

ENVIRONMENT
     MAKEOBJDIRPREFIX  If the environment variable MAKEOBJDIRPREFIX is set, the object directory
		       will be prefixed with the path contained in this environment variable.

		       Note: This variable is only used if the -o option to use existing object
		       files is also specified.

     MACHINE	       If the environment variable MACHINE is set, it is used as the name of the
		       machine type, when accessing object directories of the form obj.MACHINE.
		       If it is not set, it defaults to the machine type returned by uname(3).

		       Note: This option is only used if the -o option to use existing object
		       files is also specified.

     MAKE	       If the environment variable MAKE is set, it is used as the name of the
		       make(1) executable to be called.  If this environment variable is not set,
		       crunchgen defaults to ``make''.

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
	   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

	   libs -lutil -lcrypt

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

     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.

SEE ALSO
     crunchide(1), make(1)

AUTHORS
     crunchgen was written by James da Silva <jds@cs.umd.edu>.

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

BUGS
     While crunchgen takes care to eliminate link conflicts between the component 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'' target must then be used to get
     those object files built, or some other arrangements made.

     If a program directory being searched for is found, but contains no objects, other directo-
     ries are not searched.  This causes the following directive to fail:

	   srcdirs /usr/src/usr.bin /usr/src/usr.bin/less
	   progs less gzip

     as the /usr/src/usr.bin/less directory will be found with the /usr/src/usr.bin srcdirs
     entry, and as it does not contain the require objects, crunchgen fails to find objects for
     the less program.	To avoid this problem, list specific srcdirs first, and the more general
     ones later, for e.g.:

	   srcdirs /usr/src/usr.bin/less /usr/src/usr.bin
	   progs less gzip

     will not have the above problem.

BSD					 October 18, 2006				      BSD
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