1 files changed, 65 insertions, 0 deletions
diff --git a/pkg/sentry/fs/ext/inline_file.go b/pkg/sentry/fs/ext/inline_file.go
new file mode 100644
index 000000000..dd93ee2e1
--- /dev/null
+++ b/pkg/sentry/fs/ext/inline_file.go
@@ -0,0 +1,65 @@
+// Copyright 2019 The gVisor Authors.
+//
+// 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 ext
+
+import (
+	"io"
+)
+
+// inlineFile is a type of regular file. All the data here is stored in the
+// inode.Data() array.
+type inlineFile struct {
+	regFile regularFile
+}
+
+// Compiles only if inlineFile implements fileReader.
+var _ fileReader = (*inlineFile)(nil)
+
+// getFileReader implements fileReader.getFileReader.
+func (f *inlineFile) getFileReader(_ io.ReadSeeker, _ uint64, offset uint64) io.Reader {
+	diskInode := f.regFile.inode.diskInode
+	return &inlineReader{offset: offset, data: diskInode.Data()[:diskInode.Size()]}
+}
+
+// newInlineFile is the inlineFile constructor.
+func newInlineFile(regFile regularFile) *inlineFile {
+	file := &inlineFile{regFile: regFile}
+	file.regFile.impl = file
+	return file
+}
+
+// inlineReader implements io.Reader which can read the underlying data.
+type inlineReader struct {
+	offset uint64
+	data   []byte
+}
+
+// Compiles only if inlineReader implements io.Reader.
+var _ io.Reader = (*inlineReader)(nil)
+
+// Read implements io.Reader.Read.
+func (r *inlineReader) Read(dst []byte) (int, error) {
+	if len(dst) == 0 {
+		return 0, nil
+	}
+
+	if int(r.offset) >= len(r.data) {
+		return 0, io.EOF
+	}
+
+	n := copy(dst, r.data[r.offset:])
+	r.offset += uint64(n)
+	return n, nil
+}