check: functionality for symlinks

Default behavior (according to upstream mtree) for validating symlinks
is to just validate the link itself, not to follow it.

Signed-off-by: Stephen Chung <schung@redhat.com>

check.go

@@ -84,16 +84,25 @@ func Check(root string, dh *DirectoryHierarchy, keywords []string) (*Result, err
 				if keywords != nil && !inSlice(kv.Keyword(), keywords) {
 					continue
 				}
-				fh, err := os.Open(pathname)
-				if err != nil {
-					return nil, err
-				}
-				curKeyVal, err := keywordFunc(pathname, info, fh)
-				if err != nil {
+
+				var curKeyVal string
+				if info.Mode().IsRegular() {
+					fh, err := os.Open(pathname)
+					if err != nil {
+						return nil, err
+					}
+					curKeyVal, err = keywordFunc(pathname, info, fh)
+					if err != nil {
+						fh.Close()
+						return nil, err
+					}
 					fh.Close()
-					return nil, err
+				} else {
+					curKeyVal, err = keywordFunc(pathname, info, nil)
+					if err != nil {
+						return nil, err
+					}
 				}
-				fh.Close()
 				if string(kv) != curKeyVal {
 					failure := Failure{Path: pathname, Keyword: kv.Keyword(), Expected: kv.Value(), Got: KeyVal(curKeyVal).Value()}
 					result.Failures = append(result.Failures, failure)
@@ -174,7 +183,7 @@ func TarCheck(tarDH, dh *DirectoryHierarchy, keywords []string) (*Result, error)
 			}
 
 			for _, kv := range kvs {
-
+				// TODO: keep track of symlinks
 				if _, ok := KeywordFuncs[kv.Keyword()]; !ok {
 					return nil, fmt.Errorf("Unknown keyword %q for file %q", kv.Keyword(), pathname)
 				}

check_test.go

@@ -97,6 +97,24 @@ func ExampleCheck() {
 	}
 }
 
+// Tests default action for evaluating a symlink, which is just to compare the
+// link itself, not to follow it
+func TestDefaultBrokenLink(t *testing.T) {
+	dh, err := Walk("./testdata/dirwithbrokenlink", nil, append(DefaultKeywords, "sha1"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	res, err := Check("./testdata/dirwithbrokenlink", dh, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res != nil && len(res.Failures) > 0 {
+		for _, f := range res.Failures {
+			t.Error(f)
+		}
+	}
+}
+
 // https://github.com/vbatts/go-mtree/issues/8
 func TestTimeComparison(t *testing.T) {
 	dir, err := ioutil.TempDir("", "test-time.")

testdata/dirwithbrokenlink/deepdir/dir3/dir4/dir5/dir6/deeperfile

@@ -0,0 +1 @@
+some spacious text

testdata/dirwithbrokenlink/deepdir/dir3/dir4/dir5/dir7/deeperfile

@@ -0,0 +1 @@
+some nice text

testdata/dirwithbrokenlink/dir1/badlink

@@ -0,0 +1 @@
+badfile

testdata/dirwithbrokenlink/dir1/dir2/.hidden/goodlink

@@ -0,0 +1 @@
+../../goodfile

testdata/dirwithbrokenlink/dir1/goodfile

@@ -0,0 +1 @@
+link text