From a2a3f317b5d393d5f14865b5233aef9adf864787 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Wed, 5 Feb 2014 01:50:01 -0800
Subject: [PATCH] Make driver loading signal failure, and fix case where
 setting a driver can cause a null pointer deref

---
 src/gba/gba-sio.c | 8 ++++++--
 src/gba/gba-sio.h | 4 ++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/gba/gba-sio.c b/src/gba/gba-sio.c
index e320169ba..a5f917000 100644
--- a/src/gba/gba-sio.c
+++ b/src/gba/gba-sio.c
@@ -83,9 +83,13 @@ void GBASIOSetDriver(struct GBASIO* sio, struct GBASIODriver* driver, enum GBASI
 		driver->p = sio;
 
 		if (driver->init) {
-			driver->init(driver);
+			if (!driver->init(driver)) {
+				driver->deinit(driver);
+				GBALog(sio->p, GBA_LOG_ERROR, "Could not initialize SIO driver");
+				return;
+			}
 		}
-		if (*driverLoc == sio->activeDriver) {
+		if (*driverLoc && *driverLoc == sio->activeDriver) {
 			sio->activeDriver = driver;
 			if ((*driverLoc)->load) {
 				(*driverLoc)->load(*driverLoc);
diff --git a/src/gba/gba-sio.h b/src/gba/gba-sio.h
index 9e1fed346..6ada65f9c 100644
--- a/src/gba/gba-sio.h
+++ b/src/gba/gba-sio.h
@@ -21,11 +21,11 @@ struct GBASIO;
 struct GBASIODriver {
 	struct GBASIO* p;
 
-	void (*init)(struct GBASIODriver* driver);
+	int (*init)(struct GBASIODriver* driver);
 	void (*deinit)(struct GBASIODriver* driver);
 	int (*load)(struct GBASIODriver* driver);
 	int (*unload)(struct GBASIODriver* driver);
-	void (*writeRegister)(struct GBASIODriver* driver, uint32_t address, uint16_t value);
+	int (*writeRegister)(struct GBASIODriver* driver, uint32_t address, uint16_t value);
 	int32_t (*processEvents)(struct GBASIODriver* driver, int32_t cycles);
 };