state: check unit/service name validity

state/service.go

 package state
 
 import (
         "errors"
         "fmt"
         "labix.org/v2/mgo"
         "labix.org/v2/mgo/txn"
         "launchpad.net/juju-core/charm"
         "launchpad.net/juju-core/trivial"
         "strconv"
@@ skipping 263 matching lines @@
         }
         err := s.st.units.Find(sel).One(udoc)
         if err != nil {
                 return nil, err
         }
         return udoc, nil
 }
 
 // Unit returns the service's unit with name.
 func (s *Service) Unit(name string) (*Unit, error) {
+        if !IsUnitName(name) {
+                return nil, fmt.Errorf("%q is not a valid unit name", name)
+        }
         udoc, err := s.unitDoc(name)
         if err != nil {
                 return nil, fmt.Errorf("cannot get unit %q from service %q: %v", name, s.doc.Name, err)
         }
         return newUnit(s.st, udoc), nil
 }
 
 // AllUnits returns all units of the service.
 func (s *Service) AllUnits() (units []*Unit, err error) {
         docs := []unitDoc{}
@@ skipping 22 matching lines @@
 }
 
 // Config returns the configuration node for the service.
 func (s *Service) Config() (config *ConfigNode, err error) {
         config, err = readConfigNode(s.st, "s/"+s.Name())
         if err != nil {
                 return nil, fmt.Errorf("cannot get configuration of service %q: %v", s, err)
         }
         return config, nil
 }