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
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.
# cd /usr/src/rescue
# make obj
# make install
Note that rebuilds don't always work correctly; if you run into
trouble, try 'make clean' before recompiling.