| CRUNCHGEN(1) | General Commands Manual | CRUNCHGEN(1) | 
crunchgen —
| crunchgen | [ -fOopqSs] [-cc-file-name] [-Dsrc-root] [-dbuild-options] [-eexec-file-name] [-Llib-dir] [-mmakefile-name] [-vvar-spec] conf-file | 
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 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.
    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-D
    src-root-d
    build-options-e
    exec-file-name-f-L
    lib-dir-m
    makefile-name-Ocrunchgen 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-p-q-S-s-v
    varspeccrunchgen 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 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 ...progs progname ...libs libspec ...ln progname linknameTo 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
    keepsymbols symbols ...special progname
    srcdir pathnamespecial progname
    objdir pathnameNote: This option only takes effect if
        the -o option to use existing object files is also specified.
special progname
    objs object-file-name ...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 ...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 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.
The makefile produced by crunchgen strips
    certain sections from the final binary to reduce its size. This
  includes:
.eh_frame.eh_frame_hdr.eh_frame section..note.comment.ident.copyrightMAKEOBJDIRPREFIXMAKEOBJDIRPREFIX 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.
MACHINEMACHINE 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.
MAKEMAKE 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”.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.
crunchgen was written by James da
  Silva
  <jds@cs.umd.edu>.
Copyright (c) 1994 University of Maryland. All Rights Reserved.
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 directories 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.
| June 21, 2018 | NetBSD 9.4 |