Errata:
A format string vulnerability exists in the pw_error(3) function. This
manifests itself as a security hole in the chpass utility.
Fix:
warnx?/errx? paranoia (use "%s" not a bare string unless it is a
constant).  These are not security holes but it is worth fixing
them anyway both for robustness and so folks looking for examples
in the tree are not misled into doing something potentially dangerous.
Furthermore, it is a bad idea to assume that pathnames will not
include '%' in them and that error routines don't return strings
with '%' in them (especially in light of the possibility of locales).

.. ok deraadt@, millert@

device is opened by default).
Don't open the file w/o adding a /dev/ prefix unless the file has
a '/' in it.  This prevents problems where someone says "disklabel
sd0" with a file called "sd0" in the cwd.
The OPENDEV_DRCT flag has been deprecated as it is the the default
behavior and always has been.
Add checks for >= MAXPATHLEN and return ENAMETOOLONG in that case.

Since /tmp might be a link to /var/tmp, prune at ssh-* or .X11-unix
like the find on /tmp does.

everything fits...

o utmp lives in /var/run, not /etc
o document EX_CONFIG

errors specified by the library routine malloc(3)).

- s/MESSAGES/DIAGNOSTICS/, and put message descriptions in a nice list.
- Talk more about how using malloc() in signal handlers is bad.