CDVD: Check file actually opened before proceeding

If you loaded an invalid file, particularly with compression, the file
open may fail, leading to a division by zero (on block size), or trying
to read from nothing.

bin/resources/GameIndex.yaml

@@ -12450,6 +12450,8 @@ SLES-52710:
 SLES-52711:
   name: "Titeuf Mega Compet"
   region: "PAL-F"
+  gameFixes:
+    - GIFFIFOHack # Fixes corrupted textures.
   patches:
     958e5086:
       content: |-
@@ -25778,6 +25780,13 @@ SLPM-66294:
 SLPM-66295:
   name: "Yamiyo ni Sasayaku - Tantei Sagara Kyouichirou [Limited Edition]"
   region: "NTSC-J"
+  patches:
+    23A9A026:
+      content: |-
+        author=PSI, Jelta
+        // Game does weird stack manipulation, causing data sent to the IOP to be corrupted unless EE data cache is enabled.
+        // This patch skips over the stack code, allowing the game to boot.
+        patch=1,EE,00156888,word,10000003
 SLPM-66296:
   name: "Yamiyo ni Sasayaku - Tantei Sagara Kyouichirou"
   region: "NTSC-J"

pcsx2/CDVD/GzippedFileReader.cpp

@@ -80,7 +80,7 @@ static void WriteIndexToFile(Access* index, const char* filename)
 		return;
 	}
 
-	auto fp = FileSystem::OpenManagedCFile(filename, "rb");
+	auto fp = FileSystem::OpenManagedCFile(filename, "wb");
 	if (!fp)
 		return;
 

pcsx2/CDVD/InputIsoFile.cpp

@@ -221,7 +221,8 @@ bool InputIsoFile::Open(std::string srcfile, bool testOnly)
 		m_reader = new FlatFileReader(EmuConfig.CdvdShareWrite);
 	}
 
-	m_reader->Open(m_filename);
+	if (!m_reader->Open(m_filename))
+		return false;
 
 	// It might actually be a blockdump file.
 	// Check that before continuing with the FlatFileReader.

pcsx2/ps2/BiosTools.cpp

@@ -119,6 +119,8 @@ static bool LoadBiosVersion(std::FILE* fp, u32& version, std::string& descriptio
 			version = strtol(vermaj, (char**)NULL, 0) << 8;
 			version |= strtol(vermin, (char**)NULL, 0);
 			foundRomVer = true;
+
+			Console.WriteLn("Bios Found: %s", description.c_str());
 		}
 
 		if ((rd.fileSize % 0x10) == 0)