cp: fix -R with links

The traversal was previously not properly honoring -H/-L/-P.  Notably,
we should not have been resolving symlinks encountered during traversal
when either -H or -P are specified.

Sponsored by:	Klara, Inc.
Reviewed by:	bapt
Differential Revision:	https://reviews.freebsd.org/D34063

bin/cp/tests/cp_test.sh

@@ -43,6 +43,21 @@ basic_body()
 	check_size baz 4
 }
 
+atf_test_case basic_symlink
+basic_symlink_body()
+{
+	echo "foo" > bar
+	ln -s bar baz
+
+	atf_check cp baz foo
+	atf_check test '!' -L foo
+
+	atf_check -e inline:"cp: baz and baz are identical (not copied).\n" \
+	    -s exit:1 cp baz baz
+	atf_check -e inline:"cp: bar and baz are identical (not copied).\n" \
+	    -s exit:1 cp baz bar
+}
+
 atf_test_case chrdev
 chrdev_body()
 {
@@ -130,12 +145,61 @@ matching_srctgt_nonexistent_body()
 	atf_check -e not-empty -s not-exit:0 stat foo/dne/foo
 }
 
+recursive_link_setup()
+{
+	extra_cpflag=$1
+
+	mkdir -p foo/bar
+	ln -s bar foo/baz
+
+	mkdir foo-mirror
+	eval "cp -R $extra_cpflag foo foo-mirror"
+}
+
+atf_test_case recursive_link_dflt
+recursive_link_dflt_body()
+{
+	recursive_link_setup
+
+	# -P is the default, so this should work and preserve the link.
+	atf_check cp -R foo foo-mirror
+	atf_check test -L foo-mirror/foo/baz
+}
+
+atf_test_case recursive_link_Hflag
+recursive_link_Hflag_body()
+{
+	recursive_link_setup
+
+	# -H will not follow either, so this should also work and preserve the
+	# link.
+	atf_check cp -RH foo foo-mirror
+	atf_check test -L foo-mirror/foo/baz
+}
+
+atf_test_case recursive_link_Lflag
+recursive_link_Lflag_body()
+{
+	recursive_link_setup -L
+
+	# -L will work, but foo/baz ends up expanded to a directory.
+	atf_check test -d foo-mirror/foo/baz -a \
+	    '(' ! -L foo-mirror/foo/baz ')'
+	atf_check cp -RL foo foo-mirror
+	atf_check test -d foo-mirror/foo/baz -a \
+	    '(' ! -L foo-mirror/foo/baz ')'
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case basic
+	atf_add_test_case basic_symlink
 	atf_add_test_case chrdev
 	atf_add_test_case matching_srctgt
 	atf_add_test_case matching_srctgt_contained
 	atf_add_test_case matching_srctgt_link
 	atf_add_test_case matching_srctgt_nonexistent
+	atf_add_test_case recursive_link_dflt
+	atf_add_test_case recursive_link_Hflag
+	atf_add_test_case recursive_link_Lflag
 }