etcdserver: always check if the data dir is writable before starting …

…etcd

etcdserver/server.go

@@ -174,12 +174,17 @@ type EtcdServer struct {
 // configuration is considered static for the lifetime of the EtcdServer.
 func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
  st := store.New(StoreClusterPrefix, StoreKeysPrefix)
+
  var w *wal.WAL
  var n raft.Node
  var s *raft.MemoryStorage
  var id types.ID
  var cl *cluster
 
+ if terr := fileutil.TouchDirAll(cfg.DataDir); terr != nil {
+ return nil, fmt.Errorf("cannot access data directory: %v", terr)
+ }
+
  // Run the migrations.
  dataVer, err := version.DetectDataDir(cfg.DataDir)
  if err != nil {
@@ -250,10 +255,6 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
  cfg.PrintWithInitial()
  id, n, s, w = startNode(cfg, cl, cl.MemberIDs())
  case haveWAL:
- if err := fileutil.IsDirWriteable(cfg.DataDir); err != nil {
- return nil, fmt.Errorf("cannot write to data directory: %v", err)
- }
-
  if err := fileutil.IsDirWriteable(cfg.MemberDir()); err != nil {
  return nil, fmt.Errorf("cannot write to member directory: %v", err)
  }
@@ -290,9 +291,8 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
  return nil, fmt.Errorf("unsupported bootstrap config")
  }
 
- err = os.MkdirAll(cfg.MemberDir(), privateDirMode)
- if err != nil && err != os.ErrExist {
- return nil, err
+ if terr := fileutil.TouchDirAll(cfg.MemberDir()); terr != nil {
+ return nil, fmt.Errorf("cannot access member directory: %v", terr)
  }
 
  sstats := &stats.ServerStats{

pkg/fileutil/fileutil.go

@@ -25,6 +25,8 @@ import (
 
 const (
  privateFileMode = 0600
+ // owner can make/remove files inside the directory
+ privateDirMode = 0700
 )
 
 var (
@@ -55,3 +57,13 @@ func ReadDir(dirpath string) ([]string, error) {
  sort.Strings(names)
  return names, nil
 }
+
+// TouchDirAll is simliar to os.MkdirAll. It creates directories with 0700 permission if any directory
+// does not exists. TouchDirAll also ensures the given directory is writable.
+func TouchDirAll(dir string) error {
+ err := os.MkdirAll(dir, privateDirMode)
+ if err != nil && err != os.ErrExist {
+ return err
+ }
+ return IsDirWriteable(dir)
+}