dont chdir to dataDir

config.go

@@ -36,9 +36,9 @@ func logInfo(logger InfoLogger, msg, key, val string) {
 // If User is set it then switches to that user and the users primary group.
 // Note that this is not supported on Windows.
 //
-// If DataDir or DefaultDataDirSuffix is set, changes the current working
-// directory. If DataDirMode is nonzero, the directory will be created
-// if necessary.
+// If DataDir or DefaultDataDirSuffix is set, calculates the absolute
+// data directory path and sets DataDir. If DataDirMode is nonzero, the
+// directory will be created if necessary.
 //
 // On a non-error return, CertDir and DataDir will be absolute paths or be empty,
 // and ListenURL will be a printable and connectable URL like "http://localhost:80".
@@ -49,7 +49,7 @@ func (cfg *Config) Apply(logger InfoLogger) (l net.Listener, err error) {
 			logInfo(logger, "user switched", "user", cfg.User)
 			if cfg.DataDir, err = DefaultDataDir(cfg.DataDir, cfg.DefaultDataDirSuffix); err == nil {
 				if cfg.DataDir, err = UseDataDir(cfg.DataDir, cfg.DataDirMode); err == nil {
-					logInfo(logger, "using data directory", "dir", cfg.DataDir)
+					logInfo(logger, "data directory", "dir", cfg.DataDir)
 				}
 			}
 		}

usedatadir.go

@@ -7,10 +7,6 @@ import (
 	"path/filepath"
 )
 
-// DataDirPermissions is the permissions UseDataDir()
-// passes on to os.MkdirAll().
-var DataDirPermissions = fs.FileMode(0750)
-
 // DefaultDataDir returns dataDir if not empty, otherwise if
 // defaultSuffix is not empty it returns the joined path
 // of os.UserConfigDir() and defaultSuffix.
@@ -25,26 +21,18 @@ func DefaultDataDir(dataDir, defaultSuffix string) (string, error) {
 	return dataDir, err
 }
 
-func mkdirAll(dataDir string, mode fs.FileMode) (err error) {
-	if mode != 0 {
-		err = os.MkdirAll(dataDir, mode)
-	}
-	return
-}
-
-// UseDataDir does nothing if dataDir is empty, otherwise it expands
-// environment variables and transforms it into an absolute path.
-// Then, if mode is not zero, it creates the path if it does not exist.
-// Finally, it finally changes the current directory to it.
+// UseDataDir expands environment variables in dataDir and transforms
+// it into an absolute path. Then, if mode is not zero, it creates
+// the path if it does not exist. Does nothing if dataDir is empty.
 //
 // Returns the final path or an empty string if dataDir was empty.
 func UseDataDir(dataDir string, mode fs.FileMode) (string, error) {
 	var err error
 	if dataDir != "" {
 		dataDir = os.ExpandEnv(dataDir)
 		if dataDir, err = filepath.Abs(dataDir); err == nil {
-			if err = mkdirAll(dataDir, mode); err == nil {
-				err = os.Chdir(dataDir)
+			if mode != 0 {
+				err = os.MkdirAll(dataDir, mode)
 			}
 		}
 	}