Use exception when load content fails. ui: graceful stop on fatal error

libretro: catch/detect fatal errors and shutdown

core/dispframe.cpp

@@ -13,7 +13,7 @@ TA_context* read_frame(const char* file, u8* vram_ref = NULL);
 void rend_set_fb_scale(float x,float y);
 
 #ifdef TARGET_DISPFRAME
-void *dc_run(void*)
+void dc_run()
 {
 	struct sigaction act, segv_oact;
 	memset(&act, 0, sizeof(act));
@@ -58,6 +58,5 @@ void *dc_run(void*)
 
 		os_DoEvents();
 	}
-	return nullptr;
 }
 #endif

core/emulator.cpp

@@ -42,8 +42,10 @@ extern int screen_width, screen_height;
 std::atomic<bool> loading_canceled;
 settings_t settings;
 
-static cThread emuThread(&dc_run, nullptr);
+static void *dc_run_thread(void *);
+static cThread emuThread(&dc_run_thread, nullptr);
 static bool initDone;
+static std::string lastError;
 
 static s32 devicesInit()
 {
@@ -521,11 +523,27 @@ bool dc_is_running()
 	return sh4_cpu.IsCpuRunning();
 }
 
-#ifndef TARGET_DISPFRAME
+static void *dc_run_thread(void*)
-void* dc_run(void*)
 {
 	InitAudio();
 
+	try {
+		dc_run();
+	} catch (const FlycastException& e) {
+		ERROR_LOG(COMMON, "%s", e.what());
+		sh4_cpu.Stop();
+		lastError = e.what();
+	}
+
+    TermAudio();
+
+    return nullptr;
+}
+
+#ifndef TARGET_DISPFRAME
+
+void dc_run()
+{
 #if FEAT_SHREC != DYNAREC_NONE
 	if (config::DynarecEnabled)
 	{
@@ -557,10 +575,6 @@ void* dc_run(void*)
 			}
 		} while (resetRequested);
 	}
-
-    TermAudio();
-
-    return NULL;
 }
 #endif
 
@@ -583,8 +597,6 @@ void dc_term_emulator()
 	dc_term_game();
 	debugger::term();
 	sh4_cpu.Term();
-	if (settings.platform.system != DC_PLATFORM_DREAMCAST)
-		naomi_cart_Close();
 	custom_texture.Terminate();	// lr: avoid deadlock on exit (win32)
 	devicesTerm();
 	mem_Term();
@@ -711,6 +723,13 @@ bool dc_loadstate(const void **data, u32 size)
 	return true;
 }
 
+std::string dc_get_last_error()
+{
+	std::string error(lastError);
+	lastError.clear();
+	return error;
+}
+
 EventManager EventManager::Instance;
 
 void EventManager::registerEvent(Event event, Callback callback)

core/emulator.h

@@ -31,7 +31,7 @@ extern std::atomic<bool> loading_canceled;
 int flycast_init(int argc, char* argv[]);
 void dc_reset(bool hard);
 void dc_init();
-void* dc_run(void*);
+void dc_run();
 void dc_term();
 void dc_stop();
 void dc_term_game();
@@ -50,6 +50,7 @@ void dc_cancel_load();
 void dc_get_load_status();
 bool dc_is_running();
 void dc_resize_renderer();
+std::string dc_get_last_error();
 
 enum class Event {
 	Start,

core/imgread/cdi.cpp

@@ -1,25 +1,24 @@
 #include "common.h"
+#include "stdclass.h"
 
 #include "deps/chdpsr/cdipsr.h"
 
 Disc* cdi_parse(const char* file)
 {
-	// Only try to open .cdi files
+	if (get_file_extension(file) != "cdi")
-	size_t len = strlen(file);
-	if (len > 4 && stricmp( &file[len - 4], ".cdi"))
 		return nullptr;
 
 	FILE *fsource = nowide::fopen(file, "rb");
 
-	if (!fsource)
+	if (fsource == nullptr)
-		return nullptr;
+		throw FlycastException(std::string("Cannot open CDI file ") + file);
 
 	image_s image = { 0 };
 	track_s track = { 0 };
 	if (!CDI_init(fsource, &image, file))
 	{
 		std::fclose(fsource);
-		return nullptr;
+		throw FlycastException(std::string("Invalid CDI file ") + file);
 	}
 
 	CDI_get_sessions(fsource,&image);
@@ -41,8 +40,6 @@ Disc* cdi_parse(const char* file)
 
 		image.header_position = std::ftell(fsource);
 
-		//printf("\nSession %d has %d track(s)\n",image.global_current_session,image.tracks);
-
 		if (image.tracks == 0)
 			INFO_LOG(GDROM, "Open session");
 		else
@@ -96,8 +93,6 @@ Disc* cdi_parse(const char* file)
 				if (track.mode==0)
 					CD_DA=true;
 
-
-
 				t.ADDR=1;//hmm is that ok ?
 
 				t.CTRL=track.mode==0?0:4;
@@ -107,55 +102,30 @@ Disc* cdi_parse(const char* file)
 
 				rv->tracks.push_back(t);
 
-				//printf("\n");
-
-				//       if (track.pregap_length != 150) printf("Warning! This track seems to have a non-standard pregap...\n");
-
 				if (track.length < 0)
 					WARN_LOG(GDROM, "Negative track size found. You must extract image with /pregap option");
 
-				//if (!opts.showinfo)
+				std::fseek(fsource, track.position, SEEK_SET);
-				{
 				if (track.total_length < track.length + track.pregap_length)
 				{
 					WARN_LOG(GDROM, "This track seems truncated. Skipping...");
-						std::fseek(fsource, track.position, SEEK_SET);
+					// FIXME that can't be right
 					std::fseek(fsource, track.total_length, SEEK_CUR);
-						track.position = std::ftell(fsource);
 				}
 				else
 				{
-						
-						//printf("Track position: %lu\n",track.position + track.pregap_length * track.sector_size);
-						std::fseek(fsource, track.position, SEEK_SET);
-						//     fseek(fsource, track->pregap_length * track->sector_size, SEEK_CUR);
-						//     fseek(fsource, track->length * track->sector_size, SEEK_CUR);
 					std::fseek(fsource, track.total_length * track.sector_size, SEEK_CUR);
-
-						//savetrack(fsource, &image, &track, &opts, &flags);
-						track.position = std::ftell(fsource);
-
 					rv->EndFAD=track.start_lba +track.total_length;
-						// Generate cuesheet entries
-
-						//if (flags.create_cuesheet && !(track.mode == 2 && flags.do_convert))  // Do not generate input if converted (obsolete)
-						//	savecuesheet(fcuesheet, &image, &track, &opts, &flags);
-
-					}
 				}
+				track.position = std::ftell(fsource);
 
 				std::fseek(fsource, image.header_position, SEEK_SET);
 
-
-				// Close loops
-
 				image.remaining_tracks--;
 			}
-
-			//if (flags.create_cuesheet) fclose(fcuesheet);
 		}
 
-		CDI_skip_next_session (fsource, &image);
+		CDI_skip_next_session(fsource, &image);
 
 		image.remaining_sessions--;
 	}
@@ -167,8 +137,6 @@ Disc* cdi_parse(const char* file)
 	rv->LeadOut.ADDR=0;
 	rv->LeadOut.CTRL=0;
 
-
-
 	return rv;
 }
 

core/imgread/chd.cpp

@@ -1,9 +1,10 @@
 #include "common.h"
+#include "stdclass.h"
 
 #include <libchdr/chd.h>
 
 /* tracks are padded to a multiple of this many frames */
-const uint32_t CD_TRACK_PADDING = 4;
+constexpr uint32_t CD_TRACK_PADDING = 4;
 
 struct CHDDisc : Disc
 {
@@ -15,7 +16,7 @@ struct CHDDisc : Disc
 	u32 hunkbytes = 0;
 	u32 sph = 0;
 
-	bool TryOpen(const char* file);
+	void tryOpen(const char* file);
 
 	~CHDDisc() override
 	{
@@ -38,20 +39,21 @@ struct CHDTrack : TrackFile
 
 	CHDTrack(CHDDisc* disc, u32 StartFAD, s32 Offset, u32 fmt, bool swap_bytes)
 	{
-		this->disc=disc;
+		this->disc = disc;
-		this->StartFAD=StartFAD;
+		this->StartFAD = StartFAD;
 		this->Offset = Offset;
-		this->fmt=fmt;
+		this->fmt = fmt;
 		this->swap_bytes = swap_bytes;
 	}
 
-	void Read(u32 FAD, u8* dst, SectorFormat* sector_type, u8* subcode, SubcodeFormat* subcode_type) override
+	bool Read(u32 FAD, u8* dst, SectorFormat* sector_type, u8* subcode, SubcodeFormat* subcode_type) override
 	{
 		u32 fad_offs = FAD + Offset;
 		u32 hunk=(fad_offs)/disc->sph;
 		if (disc->old_hunk!=hunk)
 		{
-			chd_read(disc->chd,hunk,disc->hunk_mem); //CHDERR_NONE
+			if (chd_read(disc->chd,hunk,disc->hunk_mem) != CHDERR_NONE)
+				return false;
 			disc->old_hunk = hunk;
 		}
 
@@ -73,24 +75,21 @@ struct CHDTrack : TrackFile
 		//While space is reserved for it, the images contain no actual subcodes
 		//memcpy(subcode,disc->hunk_mem+hunk_ofs*(2352+96)+2352,96);
 		*subcode_type=SUBFMT_NONE;
+
+		return true;
 	}
 };
 
-bool CHDDisc::TryOpen(const char* file)
+void CHDDisc::tryOpen(const char* file)
 {
 	fp = nowide::fopen(file, "rb");
 	if (fp == nullptr)
-	{
+		throw FlycastException(std::string("Cannot open CHD file ") + file);
-		INFO_LOG(GDROM, "chd: fopen failed for file %s: %d", file, errno);
+
-		return false;
-	}
 	chd_error err = chd_open_file(fp, CHD_OPEN_READ, 0, &chd);
 
 	if (err != CHDERR_NONE)
-	{
+		throw FlycastException(std::string("Invalid CHD file ") + file);
-		INFO_LOG(GDROM, "chd: chd_open_file failed for file %s: %d", file, err);
-		return false;
-	}
 
 	INFO_LOG(GDROM, "chd: parsing file %s", file);
 
@@ -102,11 +101,8 @@ bool CHDDisc::TryOpen(const char* file)
 
 	sph = hunkbytes/(2352+96);
 
-	if (hunkbytes%(2352+96)!=0)
+	if (hunkbytes % (2352 + 96) != 0)
-	{
+		throw FlycastException(std::string("Invalid hunkbytes for CHD file ") + file);
-		INFO_LOG(GDROM, "chd: hunkbytes is invalid, %d\n",hunkbytes);
-		return false;
-	}
 
 	u32 tag;
 	u8 flags;
@@ -156,15 +152,13 @@ bool CHDDisc::TryOpen(const char* file)
 				|| pregap != 0
 				|| postgap != 0)
 		{
-			INFO_LOG(GDROM, "chd: track type %s is not supported", type);
+			throw FlycastException((std::string("chd: track type ") + type) + " is not supported");
-			return false;
 		}
 		DEBUG_LOG(GDROM, "%s", temp);
 		Track t;
 		t.StartFAD = total_frames;
 		total_frames += frames;
 		t.EndFAD = total_frames - 1;
-		t.ADDR = 0;
 		t.CTRL = strcmp(type,"AUDIO") == 0 ? 0 : 4;
 
 		t.file = new CHDTrack(this, t.StartFAD, Offset - t.StartFAD, strcmp(type, "MODE1") ? 2352 : 2048,
@@ -182,25 +176,21 @@ bool CHDDisc::TryOpen(const char* file)
 		WARN_LOG(GDROM, "WARNING: chd: Total frames is wrong: %u frames (549300 expected) in %zu tracks", total_frames, tracks.size());
 
 	FillGDSession();
-
-	return true;
 }
 
 
 Disc* chd_parse(const char* file)
 {
-	// Only try to open .chd files
+	if (get_file_extension(file) != "chd")
-	size_t len = strlen(file);
-	if (len > 4 && stricmp( &file[len - 4], ".chd"))
 		return nullptr;
 
 	CHDDisc* rv = new CHDDisc();
 
-	if (rv->TryOpen(file))
+	try {
+		rv->tryOpen(file);
 		return rv;
-	else
+	} catch (...) {
-	{
 		delete rv;
-		return 0;
+		throw;
 	}
 }

core/imgread/common.h

@@ -87,37 +87,29 @@ struct Session
 
 struct TrackFile
 {
-	virtual void Read(u32 FAD,u8* dst,SectorFormat* sector_type,u8* subcode,SubcodeFormat* subcode_type)=0;
+	virtual bool Read(u32 FAD, u8 *dst, SectorFormat *sector_type, u8 *subcode, SubcodeFormat *subcode_type) = 0;
-	virtual ~TrackFile() = default;;
+	virtual ~TrackFile() = default;
 };
 
 struct Track
 {
-	TrackFile* file;	//handler for actual IO
+	TrackFile* file = nullptr;	// handler for actual IO
-	u32 StartFAD;		//Start FAD
+	u32 StartFAD = 0;			// Start FAD
-	u32 EndFAD;			//End FAD
+	u32 EndFAD = 0;				// End FAD
-	u8 CTRL;
+	u8 CTRL = 0;
-	u8 ADDR;
+	u8 ADDR = 0;
 
-	Track()
+	bool Read(u32 FAD, u8 *dst, SectorFormat *sector_type, u8 *subcode, SubcodeFormat *subcode_type)
 	{
-		file = 0;
+		if (FAD >= StartFAD && (FAD <= EndFAD || EndFAD == 0) && file != nullptr)
-		StartFAD = 0;
+			return file->Read(FAD, dst, sector_type, subcode, subcode_type);
-		EndFAD = 0;
-		CTRL = 0;
-		ADDR = 0;
-	}
-	bool Read(u32 FAD,u8* dst,SectorFormat* sector_type,u8* subcode,SubcodeFormat* subcode_type)
-	{
-		if (FAD>=StartFAD && (FAD<=EndFAD || EndFAD==0) && file)
-		{
-			file->Read(FAD,dst,sector_type,subcode,subcode_type);
-			return true;
-		}
 		else
 			return false;
 	}
-	void Destroy() { delete file; file=0; }
+	void Destroy() {
+		delete file;
+		file = nullptr;
+	}
 };
 
 struct Disc
@@ -196,7 +188,7 @@ struct Disc
 			}
 			else
 			{
-				INFO_LOG(GDROM, "Sector Read miss FAD: %d", FAD);
+				WARN_LOG(GDROM, "Sector Read miss FAD: %d", FAD);
 			}
 			dst+=fmt;
 			FAD++;
@@ -261,18 +253,16 @@ struct RawTrackFile : TrackFile
 	FILE *file;
 	s32 offset;
 	u32 fmt;
-	bool cleanup;
 
 	RawTrackFile(FILE *file, u32 file_offs, u32 first_fad, u32 secfmt)
 	{
-		verify(file!=0);
+		verify(file != nullptr);
-		this->file=file;
+		this->file = file;
-		this->offset=file_offs-first_fad*secfmt;
+		this->offset = file_offs - first_fad * secfmt;
-		this->fmt=secfmt;
+		this->fmt = secfmt;
-		this->cleanup=true;
 	}
 
-	void Read(u32 FAD,u8* dst,SectorFormat* sector_type,u8* subcode,SubcodeFormat* subcode_type) override
+	bool Read(u32 FAD,u8* dst,SectorFormat* sector_type,u8* subcode,SubcodeFormat* subcode_type) override
 	{
 		//for now hackish
 		if (fmt==2352)
@@ -290,11 +280,15 @@ struct RawTrackFile : TrackFile
 
 		std::fseek(file, offset + FAD * fmt, SEEK_SET);
 		if (std::fread(dst, 1, fmt, file) != fmt)
+		{
 			WARN_LOG(GDROM, "Failed or truncated GD-Rom read");
+			return false;
 		}
+		return true;
+	}
+
 	~RawTrackFile() override
 	{
-		if (cleanup && file)
 		std::fclose(file);
 	}
 };

core/imgread/cue.cpp

@@ -18,6 +18,7 @@
  */
 
 #include "common.h"
+#include "stdclass.h"
 #include <sstream>
 
 extern std::string OS_dirname(std::string file);
@@ -46,15 +47,13 @@ static u32 getSectorSize(const std::string& type) {
 
 Disc* cue_parse(const char* file)
 {
-	// Only try to open .cue files
+	if (get_file_extension(file) != "cue")
-	size_t len = strlen(file);
-	if (len > 4 && stricmp( &file[len - 4], ".cue"))
 		return nullptr;
 
 	FILE *fsource = nowide::fopen(file, "rb");
 
 	if (fsource == nullptr)
-		return nullptr;
+		throw FlycastException(std::string("Cannot open CUE file ") + file);
 
 	size_t cue_len = flycast::fsize(fsource);
 
@@ -62,9 +61,8 @@ Disc* cue_parse(const char* file)
 
 	if (cue_len >= sizeof(cue_data))
 	{
-		WARN_LOG(GDROM, "CUE parse error: CUE file too big");
 		std::fclose(fsource);
-		return nullptr;
+		throw FlycastException("CUE parse error: CUE file too big");
 	}
 
 	if (std::fread(cue_data, 1, cue_len, fsource) != cue_len)
@@ -163,24 +161,21 @@ Disc* cue_parse(const char* file)
 			if (index_num == 1)
 			{
 				Track t;
-				t.ADDR = 0;
 				t.StartFAD = current_fad;
 				t.CTRL = (track_type == "AUDIO" || track_type == "CDG") ? 0 : 4;
 				std::string path = basepath + normalize_path_separator(track_filename);
 				FILE *track_file = nowide::fopen(path.c_str(), "rb");
 				if (track_file == nullptr)
 				{
-					WARN_LOG(GDROM, "CUE file: cannot open track %d: %s", track_number, path.c_str());
 					delete disc;
-					return nullptr;
+					throw FlycastException("CUE file: cannot open track " + path);
 				}
 				u32 sector_size = getSectorSize(track_type);
 				if (sector_size == 0)
 				{
-					WARN_LOG(GDROM, "CUE file: track %d has unknown sector type: %s", track_number, track_type.c_str());
 					std::fclose(track_file);
 					delete disc;
-					return nullptr;
+					throw FlycastException("CUE file: track has unknown sector type: " + track_type);
 				}
 				if (flycast::fsize(track_file) % sector_size != 0)
 					WARN_LOG(GDROM, "Warning: Size of track %s is not multiple of sector size %d", track_filename.c_str(), sector_size);
@@ -199,9 +194,8 @@ Disc* cue_parse(const char* file)
 	}
 	if (disc->tracks.empty())
 	{
-		WARN_LOG(GDROM, "CUE parse error: failed to parse or invalid file with 0 tracks");
 		delete disc;
-		return nullptr;
+		throw FlycastException("CUE parse error: failed to parse or invalid file with 0 tracks");
 	}
 
 	if (session_number == 0)

core/imgread/gdi.cpp

@@ -1,4 +1,5 @@
 #include "common.h"
+#include "stdclass.h"
 #include <algorithm>
 #include <sstream>
 
@@ -62,8 +63,8 @@ namespace {
 Disc* load_gdi(const char* file)
 {
 	FILE *t = nowide::fopen(file, "rb");
-	if (!t)
+	if (t == nullptr)
-		return nullptr;
+		throw FlycastException(std::string("Cannot open GDI file ") + file);
 
 	size_t gdi_len = flycast::fsize(t);
 
@@ -71,9 +72,8 @@ Disc* load_gdi(const char* file)
 
 	if (gdi_len >= sizeof(gdi_data))
 	{
-		WARN_LOG(GDROM, "GDI: file too big");
 		std::fclose(t);
-		return nullptr;
+		throw FlycastException("GDI file too big");
 	}
 
 	if (std::fread(gdi_data, 1, gdi_len, t) != gdi_len)
@@ -85,10 +85,8 @@ Disc* load_gdi(const char* file)
 	u32 iso_tc = 0;
 	gdi >> iso_tc;
 	if (iso_tc == 0)
-	{
+		throw FlycastException("GDI: empty or invalid GDI file");
-		WARN_LOG(GDROM, "GDI: empty or invalid GDI file");
+
-		return nullptr;
-	}
 	INFO_LOG(GDROM, "GDI : %d tracks", iso_tc);
 
 	std::string basepath = OS_dirname(file);
@@ -134,16 +132,19 @@ Disc* load_gdi(const char* file)
 		DEBUG_LOG(GDROM, "file[%d] \"%s\": FAD:%d, CTRL:%d, SSIZE:%d, OFFSET:%d", TRACK, track_filename.c_str(), FADS, CTRL, SSIZE, OFFSET);
 
 		Track t;
-		t.ADDR=0;
+		t.StartFAD = FADS + 150;
-		t.StartFAD=FADS+150;
-		t.EndFAD=0;		//fill it in
-		t.file=0;
 		t.CTRL = CTRL;
 
 		if (SSIZE!=0)
 		{
 			std::string path = basepath + normalize_path_separator(track_filename);
-			t.file = new RawTrackFile(nowide::fopen(path.c_str(), "rb"), OFFSET, t.StartFAD,SSIZE);
+			FILE *file = nowide::fopen(path.c_str(), "rb");
+			if (file == nullptr)
+			{
+				delete disc;
+				throw FlycastException("GDI file: Cannot open track " + path);
+			}
+			t.file = new RawTrackFile(file, OFFSET, t.StartFAD, SSIZE);
 		}
 		if (!disc->tracks.empty())
 			disc->tracks.back().EndFAD = t.StartFAD - 1;
@@ -158,13 +159,8 @@ Disc* load_gdi(const char* file)
 
 Disc* gdi_parse(const char* file)
 {
-	size_t len=strlen(file);
+	if (get_file_extension(file) != "gdi")
-	if (len>4)
+		return nullptr;
-	{
+
-		if (stricmp( &file[len-4],".gdi")==0)
-		{
 	return load_gdi(file);
-		}
-	}
-	return 0;
 }

core/reios/reios.cpp

@@ -394,6 +394,7 @@ static void reios_sys_misc()
 
 	case 1:	// Exit to BIOS menu
 		WARN_LOG(REIOS, "SYS_MISC 1");
+		throw FlycastException("Reboot to BIOS");
 		break;
 
 	case 2:	// check disk
@@ -645,9 +646,8 @@ static void reios_boot()
 	std::string extension = get_file_extension(settings.imgread.ImagePath);
 	if (extension == "elf")
 	{
-		if (!reios_loadElf(settings.imgread.ImagePath)) {
+		if (!reios_loadElf(settings.imgread.ImagePath))
-			msgboxf("Failed to open %s", MBX_ICONERROR, settings.imgread.ImagePath);
+			throw FlycastException(std::string("Failed to open ELF ") + settings.imgread.ImagePath);
-		}
 		reios_setup_state(0x8C010000);
 	}
 	else {
@@ -656,7 +656,7 @@ static void reios_boot()
 			char bootfile[sizeof(ip_meta.boot_filename) + 1] = {0};
 			memcpy(bootfile, ip_meta.boot_filename, sizeof(ip_meta.boot_filename));
 			if (bootfile[0] == '\0' || !reios_locate_bootfile(bootfile))
-				msgboxf("Failed to locate bootfile %s", MBX_ICONERROR, bootfile);
+				throw FlycastException(std::string("Failed to locate bootfile ") + bootfile);
 			reios_setup_state(0xac008300);
 		}
 		else {
@@ -668,14 +668,14 @@ static void reios_boot()
 			}
 			u32 data_size = 4;
 			u32* sz = (u32*)CurrentCartridge->GetPtr(0x368, data_size);
-			if (!sz || data_size != 4) {
+			if (sz == nullptr || data_size != 4)
-				msgboxf("Naomi boot failure", MBX_ICONERROR);
+				throw FlycastException("Naomi boot failure");
-			}
 
 			const u32 size = *sz;
 
 			data_size = 1;
-			verify(size < RAM_SIZE && CurrentCartridge->GetPtr(size - 1, data_size) && "Invalid cart size");
+			if (size > RAM_SIZE || CurrentCartridge->GetPtr(size - 1, data_size) == nullptr)
+				throw FlycastException("Invalid cart size");
 
 			data_size = size;
 			WriteMemBlock_nommu_ptr(0x0c020000, (u32*)CurrentCartridge->GetPtr(0, data_size), size);

core/rend/gui.cpp

@@ -432,6 +432,26 @@ static void gui_start_game(const std::string& path)
 	dc_load_game(path.empty() ? NULL : path_copy.c_str());
 }
 
+void gui_stop_game(const std::string& message)
+{
+	if (!commandLineStart)
+	{
+		// Exit to main menu
+		dc_term_game();
+		gui_state = GuiState::Main;
+		game_started = false;
+		settings.imgread.ImagePath[0] = '\0';
+		reset_vmus();
+		if (!message.empty())
+			error_msg = "Flycast has stopped.\n\n" + message;
+	}
+	else
+	{
+		// Exit emulator
+		dc_exit();
+	}
+}
+
 static void gui_display_commands()
 {
 	if (dc_is_running())
@@ -515,20 +535,7 @@ static void gui_display_commands()
 	if (ImGui::Button("Exit", ImVec2(300 * scaling + ImGui::GetStyle().ColumnsMinSpacing + ImGui::GetStyle().FramePadding.x * 2 - 1,
 			50 * scaling)))
 	{
-		if (!commandLineStart)
+		gui_stop_game();
-		{
-			// Exit to main menu
-			dc_term_game();
-			gui_state = GuiState::Main;
-			game_started = false;
-			settings.imgread.ImagePath[0] = '\0';
-			reset_vmus();
-		}
-		else
-		{
-			// Exit emulator
-			dc_exit();
-		}
 	}
 
 	ImGui::End();
@@ -909,6 +916,9 @@ static void error_popup()
 {
 	if (!error_msg.empty())
 	{
+		ImVec2 padding = ImVec2(20 * scaling, 20 * scaling);
+		ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, padding);
+		ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, padding);
 		ImGui::OpenPopup("Error");
 		if (ImGui::BeginPopupModal("Error", NULL, ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoMove))
 		{
@@ -924,8 +934,11 @@ static void error_popup()
 			}
 			ImGui::SetItemDefaultFocus();
 			ImGui::PopStyleVar();
+			ImGui::PopTextWrapPos();
 			ImGui::EndPopup();
 		}
+		ImGui::PopStyleVar();
+		ImGui::PopStyleVar();
 	}
 }
 
@@ -1918,8 +1931,12 @@ static void gui_display_content()
 						if (gui_state == GuiState::SelectDisk)
 						{
 							strcpy(settings.imgread.ImagePath, game.path.c_str());
+							try {
 								DiscSwap();
 								gui_state = GuiState::Closed;
+							} catch (const FlycastException& e) {
+								error_msg = e.what();
+							}
 						}
 						else
 						{

core/rend/gui.h

@@ -36,6 +36,7 @@ void gui_set_mouse_position(int x, int y);
 void gui_set_mouse_button(int button, bool pressed);
 void gui_set_mouse_wheel(float delta);
 void gui_set_insets(int left, int right, int top, int bottom);
+void gui_stop_game(const std::string& message = "");
 
 extern int screen_dpi;
 extern float scaling;

core/rend/mainui.cpp

@@ -49,6 +49,11 @@ bool mainui_rend_frame()
 		if (!rend_single_frame(mainui_enabled))
 		{
 			UpdateInputState();
+			if (!dc_is_running())
+			{
+				dc_stop();
+				gui_stop_game(dc_get_last_error());
+			}
 			return false;
 		}
 	}

shell/libretro/libretro.cpp

@@ -845,12 +845,26 @@ void retro_run()
 		// Render
 		is_dupe = true;
 		for (int i = 0; i < 5 && is_dupe; i++)
+		{
 			is_dupe = !rend_single_frame(true);
+			if (!dc_is_running()) {
+				std::string error = dc_get_last_error();
+				if (!error.empty())
+					gui_display_notification(error.c_str(), 5000);
+				environ_cb(RETRO_ENVIRONMENT_SHUTDOWN, NULL);
+			}
+		}
 	}
 	else
 	{
 		startTime = sh4_sched_now64();
-		dc_run(nullptr);
+		try {
+			dc_run();
+		} catch (const FlycastException& e) {
+			ERROR_LOG(COMMON, "%s", e.what());
+			gui_display_notification(e.what(), 5000);
+			environ_cb(RETRO_ENVIRONMENT_SHUTDOWN, NULL);
+		}
 	}
 
 	if (config::RendererType.isOpenGL())
@@ -870,7 +884,7 @@ static bool loadGame(const char *path)
 	} catch (const FlycastException& e) {
 		ERROR_LOG(BOOT, "%s", e.what());
 		mute_messages = false;
-		gui_display_notification(e.what(), 2000);
+		gui_display_notification(e.what(), 5000);
 		return false;
 	}
 	mute_messages = false;
@@ -2751,7 +2765,12 @@ static bool retro_set_eject_state(bool ejected)
 	}
 	else
 	{
+		try {
 			return DiscSwap();
+		} catch (const FlycastException& e) {
+			ERROR_LOG(GDROM, "%s", e.what());
+			return false;
+		}
 	}
 }
 
@@ -2779,8 +2798,13 @@ static bool retro_set_image_index(unsigned index)
 
 	if (disc_tray_open)
 		return true;
-	else
+
+	try {
 		return DiscSwap();
+	} catch (const FlycastException& e) {
+		ERROR_LOG(GDROM, "%s", e.what());
+		return false;
+	}
 }
 
 static unsigned retro_get_num_images()