From 717ecab64d1a5592275ececacb391cb768e4e289 Mon Sep 17 00:00:00 2001
From: Felicitas Pojtinger <felicitas@pojtinger.com>
Date: Tue, 25 Jan 2022 04:14:19 +0100
Subject: [PATCH] feat: Enable appending to tar archives created outside of
 STFS by seeking over EOF mark manually

---
 pkg/recovery/index.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/pkg/recovery/index.go b/pkg/recovery/index.go
index 351384e..faffb60 100644
--- a/pkg/recovery/index.go
+++ b/pkg/recovery/index.go
@@ -103,9 +103,17 @@ func Index(
 			}
 
 			if hdr == nil {
-				// EOF
+				// Try to skip over the next file mark; this makes it possible to append to a tar file created by i.e. GNU tar
+				if _, err := reader.Drive.Read(make([]byte, config.MagneticTapeBlockSize*2)); err != nil {
+					if err == io.EOF {
+						// EOF
+						break
+					}
 
-				break
+					return err
+				}
+
+				continue
 			}
 
 			if i >= offset {