In getcwd_logical(), test for a '.' or '..' component in one of the most
straightforward and intelligible ways possible.
In particular, this removes a superfluous re-test of the the component's
first character being '.' when the first one did not pass and, more
importantly, prevents the second test from relying on a side-effect in
the first.
While here, for better clarity, replace the loop that searches for '/'
with a simple call to strchrnul().
Add high-level comments about what is going on.
While here, test explicitly that pointed 'char' values are not 0 ('\0')
(style(9)).
While here, separate the successive steps of getcwd_logical() with blank
lines.
No functional change (intended).
Discussed with: emaste
Fixes: 2df923c5d2 ("pwd: Clean up and adopt POSIX semantics")
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D59709
Olivier Certner
72bb9eb7b6