Merge release-20200810.0-88-g46d11a767 (automated)

2 files changed, 30 insertions, 1 deletions

diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index 9fb351879..424b66f76 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -1,9 +1,10 @@
 package ring0
 
 import (
-	"fmt"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
+
+	"fmt"
 	"gvisor.dev/gvisor/pkg/usermem"
 	"io"
 	"reflect"
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index d3abe28ee..33910e095 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -847,3 +847,31 @@ func (fd *FileDescription) SetAsyncHandler(newHandler func() FileAsync) FileAsyn
 	}
 	return fd.asyncHandler
 }
+
+// FileReadWriteSeeker is a helper struct to pass a FileDescription as
+// io.Reader/io.Writer/io.ReadSeeker/etc.
+type FileReadWriteSeeker struct {
+	Fd    *FileDescription
+	Ctx   context.Context
+	ROpts ReadOptions
+	WOpts WriteOptions
+}
+
+// Read implements io.ReadWriteSeeker.Read.
+func (f *FileReadWriteSeeker) Read(p []byte) (int, error) {
+	dst := usermem.BytesIOSequence(p)
+	ret, err := f.Fd.Read(f.Ctx, dst, f.ROpts)
+	return int(ret), err
+}
+
+// Seek implements io.ReadWriteSeeker.Seek.
+func (f *FileReadWriteSeeker) Seek(offset int64, whence int) (int64, error) {
+	return f.Fd.Seek(f.Ctx, offset, int32(whence))
+}
+
+// Write implements io.ReadWriteSeeker.Write.
+func (f *FileReadWriteSeeker) Write(p []byte) (int, error) {
+	buf := usermem.BytesIOSequence(p)
+	ret, err := f.Fd.Write(f.Ctx, buf, f.WOpts)
+	return int(ret), err
+}