From 39be57424cdf4cc1bf8fb65bd53c2a9bef2be6a6 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Mon, 12 Aug 2024 19:13:27 +0300
Subject: [PATCH] Kernel: Fix SYS_SEEK with SEEK_END

I was subtracting the offset from file end when I should have added it.
---
 kernel/kernel/OpenFileDescriptorSet.cpp | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/kernel/kernel/OpenFileDescriptorSet.cpp b/kernel/kernel/OpenFileDescriptorSet.cpp
index 58b0dbf4..521b1637 100644
--- a/kernel/kernel/OpenFileDescriptorSet.cpp
+++ b/kernel/kernel/OpenFileDescriptorSet.cpp
@@ -217,23 +217,23 @@ namespace Kernel
 	{
 		TRY(validate_fd(fd));
 
-		off_t new_offset = 0;
-
+		off_t base_offset;
 		switch (whence)
 		{
+			case SEEK_SET:
+				base_offset = 0;
+				break;
 			case SEEK_CUR:
-				new_offset = m_open_files[fd]->offset + offset;
+				base_offset = m_open_files[fd]->offset;
 				break;
 			case SEEK_END:
-				new_offset = m_open_files[fd]->inode->size() - offset;
-				break;
-			case SEEK_SET:
-				new_offset = offset;
+				base_offset = m_open_files[fd]->inode->size();
 				break;
 			default:
 				return BAN::Error::from_errno(EINVAL);
 		}
 
+		const off_t new_offset = base_offset + offset;
 		if (new_offset < 0)
 			return BAN::Error::from_errno(EINVAL);