If we can't find the game object or game ID in fallback detection, break out instead of assuming the script is there. Fixes a segfault when detecting an LSCI game.

svn-id: r49389

2 files changed, 20 insertions, 1 deletions

diff --git a/engines/sci/detection.cpp b/engines/sci/detection.cpp
index dbd65c7aaa..aba2b0b74e 100644
--- a/engines/sci/detection.cpp
+++ b/engines/sci/detection.cpp
@@ -464,7 +464,16 @@ const ADGameDescription *SciMetaEngine::fallbackDetect(const Common::FSList &fsl
 		s_fallbackDesc.platform = Common::kPlatformAmiga;
 
 	// Determine the game id
-	Common::String gameId = convertSierraGameId(resMan->findSierraGameId(), &s_fallbackDesc.flags, resMan);
+	Common::String sierraGameId = resMan->findSierraGameId();
+
+	// If we don't have a game id, the game is not SCI
+	if (sierraGameId.empty()) {
+		SearchMan.remove("SCI_detection");
+		delete resMan;
+		return 0;
+	}
+
+	Common::String gameId = convertSierraGameId(sierraGameId, &s_fallbackDesc.flags, resMan);
 	strncpy(s_fallbackGameIdBuf, gameId.c_str(), sizeof(s_fallbackGameIdBuf) - 1);
 	s_fallbackGameIdBuf[sizeof(s_fallbackGameIdBuf) - 1] = 0;	// Make sure string is NULL terminated
 	s_fallbackDesc.gameid = s_fallbackGameIdBuf;
diff --git a/engines/sci/resource.cpp b/engines/sci/resource.cpp
index 8f4fd64d90..11d9492ad5 100644
--- a/engines/sci/resource.cpp
+++ b/engines/sci/resource.cpp
@@ -1935,6 +1935,10 @@ bool ResourceManager::hasSci1Voc900() {
 
 reg_t ResourceManager::findGameObject(bool addSci11ScriptOffset) {
 	Resource *script = findResource(ResourceId(kResourceTypeScript, 0), false);
+
+	if (!script)
+		return NULL_REG;
+
 	int extraBytes = 0;
 	if (getSciVersion() == SCI_VERSION_0_EARLY || getSciVersion() >= SCI_VERSION_1_1)
 		extraBytes = 2;
@@ -1966,8 +1970,14 @@ Common::String ResourceManager::findSierraGameId() {
 		nameSelector += 5;
 	}
 
+	if (!heap)
+		return "";
+
 	int16 gameObjectOffset = findGameObject(false).offset;
 
+	if (!gameObjectOffset)
+		return "";
+
 	// Seek to the name selector of the first export
 	byte *seeker = heap->data + READ_UINT16(heap->data + gameObjectOffset + nameSelector * 2);
 	Common::String sierraId;