From dfce234cfb2e664b2ba0907cf164873c48517cd5 Mon Sep 17 00:00:00 2001
From: Peter Veenstra <qbix79@users.sourceforge.net>
Date: Mon, 6 May 2019 08:37:53 +0000
Subject: [PATCH] Fix unitialized access to some isoDrive fields. Pause audio
 before switching. Use right subunit with multiple CDs on one driveletter.
 (krcroft, jmarsh and qbix)

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@4223
---
 src/dos/cdrom_image.cpp |  6 +++++-
 src/dos/dos_mscdex.cpp  | 11 +++++++++--
 src/dos/drive_iso.cpp   | 22 ++++++++++++++++------
 src/dos/drive_local.cpp |  5 ++++-
 4 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/src/dos/cdrom_image.cpp b/src/dos/cdrom_image.cpp
index 25a7783a..68d1806d 100644
--- a/src/dos/cdrom_image.cpp
+++ b/src/dos/cdrom_image.cpp
@@ -52,6 +52,7 @@ CDROM_Interface_Image::BinaryFile::BinaryFile(const char *filename, bool &error)
 CDROM_Interface_Image::BinaryFile::~BinaryFile()
 {
 	delete file;
+	file = NULL;
 }
 
 bool CDROM_Interface_Image::BinaryFile::read(Bit8u *buffer, int seek, int count)
@@ -128,12 +129,13 @@ int CDROM_Interface_Image::AudioFile::getLength()
 
 // initialize static members
 int CDROM_Interface_Image::refCount = 0;
-CDROM_Interface_Image* CDROM_Interface_Image::images[26];
+CDROM_Interface_Image* CDROM_Interface_Image::images[26] = {};
 CDROM_Interface_Image::imagePlayer CDROM_Interface_Image::player = {
 	NULL, NULL, NULL, {0}, 0, 0, 0, false, false, false, {0} };
 
 	
 CDROM_Interface_Image::CDROM_Interface_Image(Bit8u subUnit)
+                      :subUnit(subUnit)
 {
 	images[subUnit] = this;
 	if (refCount == 0) {
@@ -375,6 +377,7 @@ bool CDROM_Interface_Image::LoadIsoFile(char* filename)
 	track.file = new BinaryFile(filename, error);
 	if (error) {
 		delete track.file;
+		track.file = NULL;
 		return false;
 	}
 	track.number = 1;
@@ -544,6 +547,7 @@ bool CDROM_Interface_Image::LoadCueSheet(char *cuefile)
 #endif
 			if (error) {
 				delete track.file;
+				track.file = NULL;
 				success = false;
 			}
 		}
diff --git a/src/dos/dos_mscdex.cpp b/src/dos/dos_mscdex.cpp
index 23e60b31..c211bcc6 100644
--- a/src/dos/dos_mscdex.cpp
+++ b/src/dos/dos_mscdex.cpp
@@ -407,9 +407,11 @@ bool CMscdex::HasDrive(Bit16u drive) {
 }
 
 void CMscdex::ReplaceDrive(CDROM_Interface* newCdrom, Bit8u subUnit) {
-	delete cdrom[subUnit];
+	if (cdrom[subUnit] != NULL) {
+		StopAudio(subUnit);
+		delete cdrom[subUnit];
+	}
 	cdrom[subUnit] = newCdrom;
-	StopAudio(subUnit);
 }
 
 PhysPt CMscdex::GetDefaultBuffer(void) {
@@ -1298,6 +1300,11 @@ void MSCDEX_ReplaceDrive(CDROM_Interface* cdrom, Bit8u subUnit)
 	mscdex->ReplaceDrive(cdrom, subUnit);
 }
 
+Bit8u MSCDEX_GetSubUnit(char driveLetter)
+{
+	return mscdex->GetSubUnit(driveLetter-'A');
+}
+
 bool MSCDEX_GetVolumeName(Bit8u subUnit, char* name)
 {
 	return mscdex->GetVolumeName(subUnit,name);
diff --git a/src/dos/drive_iso.cpp b/src/dos/drive_iso.cpp
index 937a8a3a..9b3333d9 100644
--- a/src/dos/drive_iso.cpp
+++ b/src/dos/drive_iso.cpp
@@ -133,13 +133,22 @@ Bit16u isoFile::GetInformation(void) {
 	return 0x40;		// read-only drive
 }
 
-int  MSCDEX_RemoveDrive(char driveLetter);
-int  MSCDEX_AddDrive(char driveLetter, const char* physicalPath, Bit8u& subUnit);
-void MSCDEX_ReplaceDrive(CDROM_Interface* cdrom, Bit8u subUnit);
-bool MSCDEX_HasDrive(char driveLetter);
-bool MSCDEX_GetVolumeName(Bit8u subUnit, char* name);
+int   MSCDEX_RemoveDrive(char driveLetter);
+int   MSCDEX_AddDrive(char driveLetter, const char* physicalPath, Bit8u& subUnit);
+void  MSCDEX_ReplaceDrive(CDROM_Interface* cdrom, Bit8u subUnit);
+bool  MSCDEX_HasDrive(char driveLetter);
+bool  MSCDEX_GetVolumeName(Bit8u subUnit, char* name);
+Bit8u MSCDEX_GetSubUnit(char driveLetter);
 
-isoDrive::isoDrive(char driveLetter, const char *fileName, Bit8u mediaid, int &error) {
+isoDrive::isoDrive(char driveLetter, const char *fileName, Bit8u mediaid, int &error)
+         :iso(false),
+          dataCD(false),
+          mediaid(0),
+          fileName{'\0'},
+          subUnit(0),
+          driveLetter('\0'),
+          discLabel{'\0'}
+ {
 	nextFreeDirIterator = 0;
 	memset(dirIterators, 0, sizeof(dirIterators));
 	memset(sectorHashEntries, 0, sizeof(sectorHashEntries));
@@ -174,6 +183,7 @@ isoDrive::~isoDrive() { }
 
 int isoDrive::UpdateMscdex(char driveLetter, const char* path, Bit8u& subUnit) {
 	if (MSCDEX_HasDrive(driveLetter)) {
+		subUnit = MSCDEX_GetSubUnit(driveLetter);
 		CDROM_Interface_Image* oldCdrom = CDROM_Interface_Image::images[subUnit];
 		CDROM_Interface* cdrom = new CDROM_Interface_Image(subUnit);
 		char pathCopy[CROSS_LEN];
diff --git a/src/dos/drive_local.cpp b/src/dos/drive_local.cpp
index d2ba17d1..da8d6e59 100644
--- a/src/dos/drive_local.cpp
+++ b/src/dos/drive_local.cpp
@@ -559,7 +559,10 @@ bool MSCDEX_GetVolumeName(Bit8u subUnit, char* name);
 
 
 cdromDrive::cdromDrive(const char driveLetter, const char * startdir,Bit16u _bytes_sector,Bit8u _sectors_cluster,Bit16u _total_clusters,Bit16u _free_clusters,Bit8u _mediaid, int& error)
-		   :localDrive(startdir,_bytes_sector,_sectors_cluster,_total_clusters,_free_clusters,_mediaid) {
+		   :localDrive(startdir,_bytes_sector,_sectors_cluster,_total_clusters,_free_clusters,_mediaid),
+		    subUnit(0),
+		    driveLetter('\0')
+{
 	// Init mscdex
 	error = MSCDEX_AddDrive(driveLetter,startdir,subUnit);
 	strcpy(info, "CDRom ");