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CRUNCHGEN(1)            FreeBSD 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
     programs 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
     eliminate 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 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
             _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 behaviour 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.

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

     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.  The obj directory is
             normally calculated by looking for a directory whose name is that
             of the source directory prepended by one of the following
             components, in order of priority: the -p argument passed to the
             command 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
             processing progname.

     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).

     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
     particular 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.

SEE ALSO
     crunchide(1), make(1)

CAVEATS
     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'' 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.

FreeBSD 11.0-PRERELEASE        November 16, 2000       FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | CRUNCHGEN CONFIGURATION FILE COMMANDS | EXAMPLES | SEE ALSO | CAVEATS | AUTHORS

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