From 92a60bf4d5b0fe4705d9aa83e318f02d5ed2c0a0 Mon Sep 17 00:00:00 2001
From: madmaxoft <github@xoft.cz>
Date: Tue, 2 Sep 2014 22:40:24 +0200
Subject: Added strict error reporting to chunk loading.

This should help with #1307.
---
 src/WorldStorage/WSSAnvil.cpp | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/WorldStorage/WSSAnvil.cpp b/src/WorldStorage/WSSAnvil.cpp
index e79cc291d..0c31d8b02 100644
--- a/src/WorldStorage/WSSAnvil.cpp
+++ b/src/WorldStorage/WSSAnvil.cpp
@@ -69,6 +69,18 @@ Since only the header is actually in the memory, this number can be high, but st
 /// The maximum size of an inflated chunk; raw chunk data is 192 KiB, allow 64 KiB more of entities
 #define CHUNK_INFLATE_MAX 256 KiB
 
+#define LOAD_FAILED(CHX, CHZ) \
+	{ \
+		const int RegionX = FAST_FLOOR_DIV(CHX, 32); \
+		const int RegionZ = FAST_FLOOR_DIV(CHZ, 32); \
+		LOGERROR("%s (%d): Loading chunk [%d, %d] from file r.%d.%d.mca failed. " \
+			"The server will now abort in order to avoid further data loss. " \
+			"Please add the reported file and this message to the issue report.", \
+			__FUNCTION__, __LINE__, CHX, CHZ, RegionX, RegionZ \
+		); \
+		*((int *)0) = 0;  /* Crash intentionally */ \
+	}
+
 
 
 
@@ -263,6 +275,7 @@ bool cWSSAnvil::LoadChunkFromData(const cChunkCoords & a_Chunk, const AString &
 	inflateEnd(&strm);
 	if (res != Z_STREAM_END)
 	{
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	
@@ -271,6 +284,7 @@ bool cWSSAnvil::LoadChunkFromData(const cChunkCoords & a_Chunk, const AString &
 	if (!NBT.IsValid())
 	{
 		// NBT Parsing failed
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 
@@ -317,11 +331,13 @@ bool cWSSAnvil::LoadChunkFromNBT(const cChunkCoords & a_Chunk, const cParsedNBT
 	int Level = a_NBT.FindChildByName(0, "Level");
 	if (Level < 0)
 	{
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	int Sections = a_NBT.FindChildByName(Level, "Sections");
 	if ((Sections < 0) || (a_NBT.GetType(Sections) != TAG_List) || (a_NBT.GetChildrenType(Sections) != TAG_Compound))
 	{
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	for (int Child = a_NBT.GetFirstChild(Sections); Child >= 0; Child = a_NBT.GetNextSibling(Child))
@@ -2811,30 +2827,42 @@ bool cWSSAnvil::cMCAFile::GetChunkData(const cChunkCoords & a_Chunk, AString & a
 	}
 	unsigned ChunkLocation = ntohl(m_Header[LocalX + 32 * LocalZ]);
 	unsigned ChunkOffset = ChunkLocation >> 8;
+	if (ChunkOffset <= 2)
+	{
+		return false;
+	}
 	
 	m_File.Seek((int)ChunkOffset * 4096);
 	
 	int ChunkSize = 0;
 	if (m_File.Read(&ChunkSize, 4) != 4)
 	{
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	ChunkSize = ntohl((u_long)ChunkSize);
 	char CompressionType = 0;
 	if (m_File.Read(&CompressionType, 1) != 1)
 	{
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	if (CompressionType != 2)
 	{
 		// Chunk is in an unknown compression
+		LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
 		return false;
 	}
 	ChunkSize--;
 	
 	// HACK: This depends on the internal knowledge that AString's data() function returns the internal buffer directly
 	a_Data.assign(ChunkSize, '\0');
-	return (m_File.Read((void *)a_Data.data(), ChunkSize) == ChunkSize);
+	if (m_File.Read((void *)a_Data.data(), ChunkSize) == ChunkSize)
+	{
+		return true;
+	}
+	LOAD_FAILED(a_Chunk.m_ChunkX, a_Chunk.m_ChunkZ);
+	return false;
 }
 
 
-- 
cgit v1.2.3