config: fix parsing of file permissions

These reintroduces the braindead '744' syntax for file permissions. Even
though this number isn't octal, it is assumed by convention to be. In
order to pull this off, coerceNodes() was introduced to try to
counteract the type inferrencing that occurs during the yaml
unmarshalling. The config is unmarshalled twice: once into an empty
interface and once into the CloudConfig structure. The two resulting
node structures are combined together. The nodes from the CloudConfig
process replace those from the interface{} when the types of the two
nodes are compatible. For example, with the input `0744`, yaml
interprets that as the integer 484 giving us the nodes '0744'(string)
and 484(int). Because the types string and int are compatible, we opt to
take the string node instead of the integer.

config/config_test.go

@@ -46,6 +46,22 @@ func TestNewCloudConfig(t *testing.T) {
 			contents: "#cloud-config\ncoreos:\n  update:\n    reboot-strategy: false",
 			config:   CloudConfig{CoreOS: CoreOS{Update: Update{RebootStrategy: "false"}}},
 		},
+		{
+			contents: "#cloud-config\nwrite_files:\n  - permissions: 0744",
+			config:   CloudConfig{WriteFiles: []File{File{RawFilePermissions: "0744"}}},
+		},
+		{
+			contents: "#cloud-config\nwrite_files:\n  - permissions: 744",
+			config:   CloudConfig{WriteFiles: []File{File{RawFilePermissions: "744"}}},
+		},
+		{
+			contents: "#cloud-config\nwrite_files:\n  - permissions: '0744'",
+			config:   CloudConfig{WriteFiles: []File{File{RawFilePermissions: "0744"}}},
+		},
+		{
+			contents: "#cloud-config\nwrite_files:\n  - permissions: '744'",
+			config:   CloudConfig{WriteFiles: []File{File{RawFilePermissions: "744"}}},
+		},
 	}
 
 	for i, tt := range tests {

config/validate/validate.go

@@ -65,7 +65,6 @@ func validateCloudConfig(config []byte, rules []rule) (report Report, err error)
 		return report, err
 	}
 
-	c = normalizeNodeNames(c, &report)
 	for _, r := range rules {
 		r(c, &report)
 	}
@@ -75,30 +74,79 @@ func validateCloudConfig(config []byte, rules []rule) (report Report, err error)
 // parseCloudConfig parses the provided config into a node structure and logs
 // any parsing issues into the provided report. Unrecoverable errors are
 // returned as an error.
-func parseCloudConfig(config []byte, report *Report) (n node, err error) {
-	var raw map[interface{}]interface{}
-	if err := yaml.Unmarshal(config, &raw); err != nil {
+func parseCloudConfig(cfg []byte, report *Report) (node, error) {
+	yaml.UnmarshalMappingKeyTransform = func(nameIn string) (nameOut string) {
+		return nameIn
+	}
+	// unmarshal the config into an implicitly-typed form. The yaml library
+	// will implicitly convert types into their normalized form
+	// (e.g. 0744 -> 484, off -> false).
+	var weak map[interface{}]interface{}
+	if err := yaml.Unmarshal(cfg, &weak); err != nil {
 		matches := yamlLineError.FindStringSubmatch(err.Error())
 		if len(matches) == 3 {
 			line, err := strconv.Atoi(matches[1])
 			if err != nil {
-				return n, err
+				return node{}, err
 			}
 			msg := matches[2]
 			report.Error(line, msg)
-			return n, nil
+			return node{}, nil
 		}
 
 		matches = yamlError.FindStringSubmatch(err.Error())
 		if len(matches) == 2 {
 			report.Error(1, matches[1])
-			return n, nil
+			return node{}, nil
 		}
 
-		return n, errors.New("couldn't parse yaml error")
+		return node{}, errors.New("couldn't parse yaml error")
+	}
+	w := NewNode(weak, NewContext(cfg))
+	w = normalizeNodeNames(w, report)
+
+	// unmarshal the config into the explicitly-typed form.
+	yaml.UnmarshalMappingKeyTransform = func(nameIn string) (nameOut string) {
+		return strings.Replace(nameIn, "-", "_", -1)
+	}
+	var strong config.CloudConfig
+	if err := yaml.Unmarshal([]byte(cfg), &strong); err != nil {
+		return node{}, err
+	}
+	s := NewNode(strong, NewContext(cfg))
+
+	// coerceNodes weak nodes and strong nodes. strong nodes replace weak nodes
+	// if they are compatible types (this happens when the yaml library
+	// converts the input).
+	// (e.g. weak 484 is replaced by strong 0744, weak 4 is not replaced by
+	// strong false)
+	return coerceNodes(w, s), nil
+}
+
+// coerceNodes recursively evaluates two nodes, returning a new node containing
+// either the weak or strong node's value and its recursively processed
+// children. The strong node's value is used if the two nodes are leafs, are
+// both valid, and are compatible types (defined by isCompatible()). The weak
+// node is returned in all other cases. coerceNodes is used to counteract the
+// effects of yaml's automatic type conversion. The weak node is the one
+// resulting from unmarshalling into an empty interface{} (the type is
+// inferred). The strong node is the one resulting from unmarshalling into a
+// struct. If the two nodes are of compatible types, the yaml library correctly
+// parsed the value into the strongly typed unmarshalling. In this case, we
+// prefer the strong node because its actually the type we are expecting.
+func coerceNodes(w, s node) node {
+	n := w
+	n.children = nil
+	if len(w.children) == 0 && len(s.children) == 0 &&
+		w.IsValid() && s.IsValid() &&
+		isCompatible(w.Kind(), s.Kind()) {
+		n.Value = s.Value
 	}
 
-	return NewNode(raw, NewContext(config)), nil
+	for _, cw := range w.children {
+		n.children = append(n.children, coerceNodes(cw, s.Child(cw.name)))
+	}
+	return n
 }
 
 // normalizeNodeNames replaces all occurences of '-' with '_' within key names

config/validate/validate_test.go

@@ -65,6 +65,31 @@ func TestValidateCloudConfig(t *testing.T) {
 			rules: []rule{func(_ node, _ *Report) { panic("something happened") }},
 			err:   errors.New("something happened"),
 		},
+		{
+			config: "write_files:\n  - permissions: 0744",
+			rules:  Rules,
+		},
+		{
+			config: "write_files:\n  - permissions: '0744'",
+			rules:  Rules,
+		},
+		{
+			config: "write_files:\n  - permissions: 744",
+			rules:  Rules,
+		},
+		{
+			config: "write_files:\n  - permissions: '744'",
+			rules:  Rules,
+		},
+		{
+			config: "coreos:\n  update:\n    reboot-strategy: off",
+			rules:  Rules,
+		},
+		{
+			config: "coreos:\n  update:\n    reboot-strategy: false",
+			rules:  Rules,
+			report: Report{entries: []Entry{{entryError, "invalid value false", 3}}},
+		},
 	}
 
 	for _, tt := range tests {

system/file.go

@@ -43,7 +43,7 @@ func (f *File) Permissions() (os.FileMode, error) {
 	}
 
 	// Parse string representation of file mode as integer
-	perm, err := strconv.ParseInt(f.RawFilePermissions, 0, 32)
+	perm, err := strconv.ParseInt(f.RawFilePermissions, 8, 32)
 	if err != nil {
 		return 0, fmt.Errorf("Unable to parse file permissions %q as integer", f.RawFilePermissions)
 	}

system/file_test.go

@@ -97,7 +97,7 @@ func TestDecimalFilePermissions(t *testing.T) {
 
 	wf := File{config.File{
 		Path:               fn,
-		RawFilePermissions: "484", // Decimal representation of 0744
+		RawFilePermissions: "744",
 	}}
 
 	path, err := WriteFile(&wf, dir)