feat: add option to change ownership of dir/files to acct settings

When enabled, any new directories or files created through the
gateway will change ownership based on the account uid/gid.

Fixes #238.

backend/mkdir.go

@@ -0,0 +1,81 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// MkdirAll borrowed from stdlib to add ability to set ownership
+// as directories are created
+
+package backend
+
+import (
+	"io/fs"
+	"os"
+
+	"github.com/versity/versitygw/s3err"
+)
+
+var (
+	// TODO: make this configurable
+	defaultDirPerm fs.FileMode = 0755
+)
+
+// MkdirAll is similar to os.MkdirAll but it will return
+// ErrObjectParentIsFile when appropriate
+// MkdirAll creates a directory named path,
+// along with any necessary parents, and returns nil,
+// or else returns an error.
+// The permission bits perm (before umask) are used for all
+// directories that MkdirAll creates.
+// Any newly created directory is set to provided uid/gid ownership.
+// If path is already a directory, MkdirAll does nothing
+// and returns nil.
+// Any directoy created will be set to provided uid/gid ownership
+// if doChown is true.
+func MkdirAll(path string, uid, gid int, doChown bool) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := os.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return s3err.GetAPIError(s3err.ErrObjectParentIsFile)
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent.
+		err = MkdirAll(path[:j-1], uid, gid, doChown)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = os.Mkdir(path, defaultDirPerm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	if doChown {
+		err = os.Chown(path, uid, gid)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}