From f5ab68a2c698db36bd5fcd4caba5d987de957fe4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Herv=C3=A9=20Poussineau?= <hpoussin@reactos.org>
Date: Tue, 13 Jan 2015 20:08:23 +0000
Subject: [PATCH] [FREELDR] PXE: support backward seeking

svn path=/trunk/; revision=66035
---
 reactos/boot/freeldr/freeldr/fs/pxe.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/reactos/boot/freeldr/freeldr/fs/pxe.c b/reactos/boot/freeldr/freeldr/fs/pxe.c
index e6d2496c1af..54deaac4ccc 100644
--- a/reactos/boot/freeldr/freeldr/fs/pxe.c
+++ b/reactos/boot/freeldr/freeldr/fs/pxe.c
@@ -263,8 +263,13 @@ static ARC_STATUS PxeSeek(ULONG FileId, LARGE_INTEGER* Position, SEEKMODE SeekMo
         return EINVAL;
 
     if (!_CachedFile && Position->LowPart < _FilePosition)
-        // We don't support backward seek without caching
-        return EINVAL;
+    {
+        // Close and reopen the file to go to position 0
+        if (PxeClose(FileId) != ESUCCESS)
+            return EIO;
+        if (PxeOpen(_OpenFileName, OpenReadOnly, &FileId) != ESUCCESS)
+            return EIO;
+    }
 
     RtlZeroMemory(&readData, sizeof(readData));
     readData.Buffer.segment = ((UINT32)_Packet & 0xf0000) / 16;