1 files changed, 141 insertions, 0 deletions
diff --git a/sd_login/util_valid.go b/sd_login/util_valid.go
new file mode 100644
index 0000000..e0dd906
--- /dev/null
+++ b/sd_login/util_valid.go
@@ -0,0 +1,141 @@
+// Copyright (C) 2016 Luke Shumaker <lukeshu@sbcglobal.net>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sd_login
+
+import (
+	"strings"
+)
+
+func valid_session_name(id string) bool {
+	if id == "" {
+		return false
+	}
+
+	return strings.TrimLeft(id, letters+digits) == ""
+}
+
+func valid_slice_name(s string) bool {
+	return strings.HasSuffix(s, ".slice") && valid_unit_name(s) == unit_name_plain
+}
+
+func valid_machine_name(s string) bool {
+	if len(s) > host_name_max {
+		// Note that Linux HOST_NAME_MAX is 64, but DNS allows
+		// 255, so names from DNS might be invalid.
+		return false
+	}
+
+	n_dots := 0
+	dot := true
+	for _, c := range s {
+		if c == '.' {
+			if dot {
+				return false
+			}
+			dot = true
+			n_dots++
+		} else {
+			if !strings.ContainsRune(letters+digits+"-_.", c) {
+				return false
+			}
+			dot = false
+		}
+	}
+
+	if dot { // trailing dot or empty
+		return false
+	}
+
+	return true
+}
+
+const (
+	unit_name_invalid  = 0
+	unit_name_plain    = 1 << 0 // foo.service
+	unit_name_instance = 1 << 1 // foo@bar.service
+	unit_name_template = 1 << 2 // foo@.service
+	unit_name_any      = unit_name_plain | unit_name_instance | unit_name_template
+)
+
+func valid_unit_name(unit string) int {
+	const_unit_name_max := 256
+	const_unit_types := []string{
+		"service",
+		"socket",
+		"busname",
+		"target",
+		"device",
+		"mount",
+		"automount",
+		"swap",
+		"timer",
+		"path",
+		"slice",
+		"scope",
+	}
+
+	if unit == "" {
+		return unit_name_invalid
+	}
+
+	// If the unit name is too long
+	if len(unit) >= const_unit_name_max {
+		return unit_name_invalid
+	}
+
+	// If there is no dot in the unit name
+	dot := strings.LastIndexByte(unit, '.')
+	if dot < 0 || dot == 0 {
+		return unit_name_invalid
+	}
+
+	// If the .suffix isn't a real unit type
+	utype := unit[dot+1:]
+	found := false
+	for _, _utype := range const_unit_types {
+		if utype == _utype {
+			found = true
+			break
+		}
+	}
+	if !found {
+		return unit_name_invalid
+	}
+
+	at := strings.IndexByte(unit, '@')
+
+	// If the unit has more than one '@'
+	if at >= 0 && strings.IndexByte(unit[at+1:], '@') >= 0 {
+		return unit_name_invalid
+	}
+
+	// If the '@' is at the start of the unit
+	if at == 0 {
+		return unit_name_invalid
+	}
+
+	if at < 0 {
+		return unit_name_plain
+	} else {
+		if dot > at+1 {
+			return unit_name_instance
+		}
+		if dot == at+1 {
+			return unit_name_template
+		}
+	}
+
+	return unit_name_invalid
+}