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
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,
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
utility uses the companion program
crunchide(1)
to eliminate link-time conflicts between the component programs by
hiding all unnecessary symbols.
The
utility places specific requirements on package
Makefile s
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
looks for the file
Makefile.foo
in the current directory.
After
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
Makefile s
generated by
.
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
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
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
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.
Multiple
libs_so
lines can be specified.
The
libs_so
directive overrides 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
available or not built via a conventional
Makefile
the following
special
commands can be used to set
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
Makefile s
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
Qq Li foo.bar
and
Qq Li foobar
to map to the same identifier.
Only the
objpaths
parameter is actually needed by
,
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
calculate forward from there if it can.
The makefile produced by
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
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.
While
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
An -nosplit
The
utility was written by
An James da Silva Aq jds@cs.umd.edu .
Copyright (c) 1994 University of Maryland.
All Rights Reserved.
The
libs_so
keyword was added in 2005 by
An Adrian Steinmann Aq ast@marabu.ch
and
An Ceri Davies Aq ceri@FreeBSD.org .
