chgrp, chown: Don't prohibit -RLh, aka -RL with --no-dereference.

* src/chgrp.c (main): Don't prohibit -RLh, aka -RL with --no-dereference.
* src/chown.c (main): Likewise.
* src/chown-core.c (change_file_owner): Add to a comment.
* tests/chown/preserve-root: Add tests.
* doc/coreutils.texi (Treating / specially): With --preserve-root,
chgrp and chown will not modify "/", even through a symlink.

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/chown/preserve-root b/tests/chown/preserve-root
index 152f59c30..4f8fe4f7f 100755
--- a/tests/chown/preserve-root
+++ b/tests/chown/preserve-root
@@ -55,6 +55,18 @@ chgrp -R --preserve-root 0 / >> out 2>&1 && fail=1
 # and then, only to make them readable by owner.
 chmod -R --preserve-root u+r / >> out 2>&1 && fail=1
 
+# With -RHh, --preserve-root should trigger nothing,
+# since the symlink in question is not a command line argument.
+# Contrary to the above commands, these two should succeed.
+echo '==== test -RHh' >> out
+chown -RHh --preserve-root `id -u` d >> out 2>&1 || fail=1
+chgrp -RHh --preserve-root `id -g` d >> out 2>&1 || fail=1
+
+# These must fail.
+echo '==== test -RLh' >> out
+chown -RLh --preserve-root `id -u` d >> out 2>&1 && fail=1
+chgrp -RLh --preserve-root `id -g` d >> out 2>&1 && fail=1
+
 cat <<\EOF > exp || fail=1
 chown: it is dangerous to operate recursively on `/'
 chown: use --no-preserve-root to override this failsafe
@@ -62,6 +74,12 @@ chgrp: it is dangerous to operate recursively on `/'
 chgrp: use --no-preserve-root to override this failsafe
 chmod: it is dangerous to operate recursively on `/'
 chmod: use --no-preserve-root to override this failsafe
+==== test -RHh
+==== test -RLh
+chown: it is dangerous to operate recursively on `d/slink-to-root' (same as `/')
+chown: use --no-preserve-root to override this failsafe
+chgrp: it is dangerous to operate recursively on `d/slink-to-root' (same as `/')
+chgrp: use --no-preserve-root to override this failsafe
 EOF
 
 cmp out exp || fail=1