Resolve relative paths before testing if the path exists.

Trying to go beyond the root dir with '..' should just go back to the root dir. We need to resolve that before mapping to the host's filesystem.

Source/iop/Iop_McServ.cpp

@@ -131,17 +131,21 @@ std::string CMcServ::MakeAbsolutePath(const std::string& inputPath)
 {
 	auto frags = StringUtils::Split(inputPath, '/', true);
 	std::vector<std::string> newFrags;
-	for(auto fragIterator = std::rbegin(frags);
-	    fragIterator != std::rend(frags); fragIterator++)
+	for(const auto& frag : frags)
 	{
-		if(*fragIterator == "..")
+		if(frag.empty()) continue;
+		if(frag == "..")
 		{
-			fragIterator++;
-			fragIterator++;
+			if(newFrags.empty())
+			{
+				//Going up too much, don't bother
+				continue;
+			}
+			newFrags.pop_back();
 		}
 		else
 		{
-			newFrags.insert(std::begin(newFrags), *fragIterator);
+			newFrags.push_back(frag);
 		}
 	}
 	auto outputPath = std::string();
@@ -711,19 +715,20 @@ void CMcServ::ChDir(uint32* args, uint32 argsSize, uint32* ret, uint32 retSize,
 			newCurrentDirectory = currentDirectory + SEPARATOR_CHAR + requestedDirectory;
 		}
 
+		newCurrentDirectory = MakeAbsolutePath(newCurrentDirectory);
+
 		auto mcPath = CAppConfig::GetInstance().GetPreferencePath(m_mcPathPreference[cmd->port]);
 		auto hostPath = Iop::PathUtils::MakeHostPath(mcPath, newCurrentDirectory.c_str());
 
 		if(!Iop::PathUtils::IsInsideBasePath(mcPath, hostPath))
 		{
-			//Some games (EA games) will try to ChDir('..') from the MC's root
-			//Kim Possible: What's the Switch will also attempt this and rely on the result
-			//to consider other MC operations to be successes
-			result = 0;
+			//This shouldn't happen, but fail just in case.
+			assert(false);
+			result = RET_NO_ENTRY;
 		}
 		else if(fs::exists(hostPath) && fs::is_directory(hostPath))
 		{
-			currentDirectory = MakeAbsolutePath(newCurrentDirectory);
+			currentDirectory = newCurrentDirectory;
 			result = 0;
 		}
 		else