From bfdd89218dd4dce007d5e26da8315d22a88079ac Mon Sep 17 00:00:00 2001
From: Edoardo Lolletti <edoardo762@gmail.com>
Date: Sat, 27 Apr 2024 23:31:07 +0200
Subject: [PATCH] Properly detect case where deviceList was populated with
 garbage data

Assume the device list is valid if it has a valid device that matches the path of the app
---
 arm9/src/deviceList.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/arm9/src/deviceList.c b/arm9/src/deviceList.c
index 498a2cc..f3ec1e8 100644
--- a/arm9/src/deviceList.c
+++ b/arm9/src/deviceList.c
@@ -4,6 +4,8 @@
 #define DEVICE_LIST_SENTINEL *(vu32*)0x02300020
 #define DEVICE_LIST_ADDR (vu8*)0x02300024
 
+static u8 gotDeviceList = 0;
+
 size_t getDeviceNameLenFromAppName(const char (appname)[0x40])
 {
 	for(int i = 0; i < 0x40; ++i)
@@ -18,39 +20,40 @@ size_t getDeviceNameLenFromAppName(const char (appname)[0x40])
 
 DeviceList* getDeviceList(void)
 {
-	static bool gotDeviceList = false;
 	if(!gotDeviceList) {
+		gotDeviceList = 1;
 		while(!DEVICE_LIST_SENTINEL);
 		DeviceList* list = (DeviceList*)DEVICE_LIST_ADDR;
-		
+
 		size_t deviceNameLen = getDeviceNameLenFromAppName(list->appname);
-		
+
 		if(deviceNameLen == 0)
 		{
 			return 0;
 		}
-		bool isSd = false;
-		
+
 		for(int i = 0; i < 11; ++i)
 		{
 			Device* device = &list->devices[i];
 			if(device->deviceName[deviceNameLen] == '\0' && strncmp(device->deviceName, list->appname, deviceNameLen) == 0)
 			{
-				isSd = device->phisicalDrive == 0;
+				gotDeviceList = 2;
+				bool isSd = device->phisicalDrive == 0;
+				if(isSd)
+				{
+					//transform the root path to sd:/ (can be sdmc:/, nand:/,  nand2:/, etc)
+					memmove(list->appname + 2, list->appname + deviceNameLen, sizeof(list->appname) - deviceNameLen);
+					list->appname[0] = 's';
+					list->appname[1] = 'd';
+					memset(list->appname + (sizeof(list->appname) - deviceNameLen + 2), 0, deviceNameLen - 2);
+				}
 				break;
 			}
 		}
-		
-		if(isSd)
-		{
-			//transform the root path to sd:/ (can be sdmc:/, nand:/,  nand2:/, etc)
-			memmove(list->appname + 2, list->appname + deviceNameLen, sizeof(list->appname) - deviceNameLen);
-			list->appname[0] = 's';
-			list->appname[1] = 'd';
-			memset(list->appname + (sizeof(list->appname) - deviceNameLen + 2), 0, deviceNameLen - 2);
-		}
-		gotDeviceList = true;
 	}
-	
+
+	if(gotDeviceList == 1)
+		return 0;
+
 	return (DeviceList*)DEVICE_LIST_ADDR;
 }
\ No newline at end of file