From 16cf38998672f6b4b9c0c8aae2dcdd75b9af9725 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Sun, 20 Jul 2014 01:36:18 -0700
Subject: [PATCH] Make writing to RO mapped memory perform COW

---
 src/gba/gba-savedata.c  | 6 +++---
 src/gba/gba-serialize.c | 2 +-
 src/gba/gba.c           | 4 ++--
 src/util/memory.h       | 3 ---
 src/util/vfs.c          | 8 ++++----
 src/util/vfs.h          | 5 ++++-
 6 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/gba/gba-savedata.c b/src/gba/gba-savedata.c
index 3acb4cdc6..1c61c03dc 100644
--- a/src/gba/gba-savedata.c
+++ b/src/gba/gba-savedata.c
@@ -85,7 +85,7 @@ void GBASavedataInitFlash(struct GBASavedata* savedata) {
 		if (end < SIZE_CART_FLASH512) {
 			savedata->vf->truncate(savedata->vf, SIZE_CART_FLASH1M);
 		}
-		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_FLASH1M, MEMORY_WRITE);
+		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_FLASH1M, MAP_WRITE);
 	}
 
 	savedata->currentBank = savedata->data;
@@ -110,7 +110,7 @@ void GBASavedataInitEEPROM(struct GBASavedata* savedata) {
 		if (end < SIZE_CART_EEPROM) {
 			savedata->vf->truncate(savedata->vf, SIZE_CART_EEPROM);
 		}
-		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_EEPROM, MEMORY_WRITE);
+		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_EEPROM, MAP_WRITE);
 	}
 	if (end < SIZE_CART_EEPROM) {
 		memset(&savedata->data[end], 0xFF, SIZE_CART_EEPROM - end);
@@ -133,7 +133,7 @@ void GBASavedataInitSRAM(struct GBASavedata* savedata) {
 		if (end < SIZE_CART_SRAM) {
 			savedata->vf->truncate(savedata->vf, SIZE_CART_SRAM);
 		}
-		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_SRAM, MEMORY_WRITE);
+		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_SRAM, MAP_WRITE);
 	}
 
 	if (end < SIZE_CART_SRAM) {
diff --git a/src/gba/gba-serialize.c b/src/gba/gba-serialize.c
index 9fa349cb8..62addac5a 100644
--- a/src/gba/gba-serialize.c
+++ b/src/gba/gba-serialize.c
@@ -99,7 +99,7 @@ bool GBALoadState(struct GBA* gba, int slot) {
 }
 
 struct GBASerializedState* GBAMapState(struct VFile* vf) {
-	return vf->map(vf, sizeof(struct GBASerializedState), MEMORY_WRITE);
+	return vf->map(vf, sizeof(struct GBASerializedState), MAP_WRITE);
 }
 
 void GBAUnmapState(struct VFile* vf, struct GBASerializedState* state) {
diff --git a/src/gba/gba.c b/src/gba/gba.c
index 79530b8d6..435ab5287 100644
--- a/src/gba/gba.c
+++ b/src/gba/gba.c
@@ -386,7 +386,7 @@ void GBALoadROM(struct GBA* gba, struct VFile* vf, struct VFile* sav, const char
 	gba->romVf = vf;
 	gba->pristineRomSize = vf->seek(vf, 0, SEEK_END);
 	vf->seek(vf, 0, SEEK_SET);
-	gba->pristineRom = vf->map(vf, SIZE_CART0, MEMORY_READ);
+	gba->pristineRom = vf->map(vf, SIZE_CART0, MAP_READ);
 	gba->memory.rom = gba->pristineRom;
 	gba->activeFile = fname;
 	gba->memory.romSize = gba->pristineRomSize;
@@ -398,7 +398,7 @@ void GBALoadROM(struct GBA* gba, struct VFile* vf, struct VFile* sav, const char
 
 void GBALoadBIOS(struct GBA* gba, struct VFile* vf) {
 	gba->biosVf = vf;
-	gba->memory.bios = vf->map(vf, SIZE_BIOS, MEMORY_READ);
+	gba->memory.bios = vf->map(vf, SIZE_BIOS, MAP_READ);
 	gba->memory.fullBios = 1;
 	uint32_t checksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
 	GBALog(gba, GBA_LOG_DEBUG, "BIOS Checksum: 0x%X", checksum);
diff --git a/src/util/memory.h b/src/util/memory.h
index e9539ef1f..510049e8f 100644
--- a/src/util/memory.h
+++ b/src/util/memory.h
@@ -3,9 +3,6 @@
 
 #include "common.h"
 
-#define MEMORY_READ 1
-#define MEMORY_WRITE 2
-
 void* anonymousMemoryMap(size_t size);
 void mappedMemoryFree(void* memory, size_t size);
 
diff --git a/src/util/vfs.c b/src/util/vfs.c
index ce1457968..f536e164b 100644
--- a/src/util/vfs.c
+++ b/src/util/vfs.c
@@ -105,7 +105,7 @@ ssize_t _vfdWrite(struct VFile* vf, void* buffer, size_t size) {
 static void* _vfdMap(struct VFile* vf, size_t size, int flags) {
 	struct VFileFD* vfd = (struct VFileFD*) vf;
 	int mmapFlags = MAP_PRIVATE;
-	if (flags & MEMORY_WRITE) {
+	if (flags & MAP_WRITE) {
 		mmapFlags = MAP_SHARED;
 	}
 	return mmap(0, size, PROT_READ | PROT_WRITE, mmapFlags, vfd->fd, 0);
@@ -118,9 +118,9 @@ static void _vfdUnmap(struct VFile* vf, void* memory, size_t size) {
 #else
 static void* _vfdMap(struct VFile* vf, size_t size, int flags) {
 	struct VFileFD* vfd = (struct VFileFD*) vf;
-	int createFlags = PAGE_READONLY;
-	int mapFiles = FILE_MAP_READ;
-	if (flags & MEMORY_WRITE) {
+	int createFlags = PAGE_WRITECOPY;
+	int mapFiles = FILE_MAP_COPY;
+	if (flags & MAP_WRITE) {
 		createFlags = PAGE_READWRITE;
 		mapFiles = FILE_MAP_WRITE;
 	}
diff --git a/src/util/vfs.h b/src/util/vfs.h
index c64f0a5eb..90cac8f19 100644
--- a/src/util/vfs.h
+++ b/src/util/vfs.h
@@ -3,7 +3,10 @@
 
 #include "common.h"
 
-#include "memory.h"
+enum {
+	MAP_READ = 1,
+	MAP_WRITE = 2
+};
 
 struct VFile {
 	bool (*close)(struct VFile* vf);