freebsd-src/rescue

The /rescue build system here has three goals:

1) Produce a reliable standalone set of /rescue tools.

The contents of /rescue are all statically linked and do not depend on
anything in /bin or /sbin.  In particular, they'll continue to
function even if you've hosed your dynamic /bin and /sbin.  For
example, note that /rescue/mount runs /rescue/mount_nfs and not
/sbin/mount_nfs.  This is more subtle than it looks.

As an added bonus, /rescue is fairly small (thanks to crunchgen) and
includes a number of tools (such as gzip, bzip2, vi) that are not
normally found in /bin and /sbin.

2) Demonstrate robust use of crunchgen.

These Makefiles recompile each of the crunchgen components and include
support for overriding specific library entries.  Such techniques
should be useful elsewhere.

3) Produce a toolkit suitable for small distributions.

Install /rescue on a CD or CompactFlash disk, and symlink /bin and
/sbin to /rescue to produce a small and fairly complete FreeBSD
system.

These tools have one big disadvantage: being statically linked, they
cannot use some advanced library functions that rely on dynamic
linking.  In particular, nsswitch, locales, and pam all
rely on dynamic linking.


To compile:

# cd /usr/src/rescue
# make obj
# make
# make install

Note that rebuilds don't always work correctly; if you run into
trouble, try 'make clean' before recompiling.