coreinit: Fix FSGetMountSource and FSAppendFile implementation (#863)

Fixes SD access in SSBU

Author: Maschell

src/Cafe/IOSU/fsa/iosu_fsa.cpp

@@ -611,14 +611,13 @@ namespace iosu
 
 		FSA_RESULT FSAProcessCmd_appendFile(FSAClient* client, FSAShimBuffer* shimBuffer)
 		{
-			uint32 fileHandle = shimBuffer->request.cmdAppendFile.fileHandle;
-			FSCVirtualFile* fscFile = sFileHandleTable.GetByHandle(fileHandle);
+			FSCVirtualFile* fscFile = sFileHandleTable.GetByHandle(shimBuffer->request.cmdAppendFile.fileHandle);
 			if (!fscFile)
 				return FSA_RESULT::INVALID_FILE_HANDLE;
 #ifdef CEMU_DEBUG_ASSERT
 			cemuLog_log(LogType::Force, "FSAProcessCmd_appendFile(): size 0x{:08x} count 0x{:08x} (todo)\n", shimBuffer->request.cmdAppendFile.size, shimBuffer->request.cmdAppendFile.count);
 #endif
-			return (FSA_RESULT)(shimBuffer->request.cmdAppendFile.size * shimBuffer->request.cmdAppendFile.count);
+			return (FSA_RESULT)(shimBuffer->request.cmdAppendFile.count.value());
 		}
 
 		FSA_RESULT FSAProcessCmd_truncateFile(FSAClient* client, FSAShimBuffer* shimBuffer)

src/Cafe/OS/libs/coreinit/coreinit_FS.cpp

@@ -74,32 +74,39 @@ namespace coreinit
 
 	FS_RESULT FSGetMountSourceNext(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, MOUNT_TYPE mountSourceType, FS_MOUNT_SOURCE* mountSourceInfo, FS_ERROR_MASK errMask)
 	{
-		// hacky
-		static FS_MOUNT_SOURCE* s_last_source = nullptr;
-		if (s_last_source != mountSourceInfo)
+		if (mountSourceType == MOUNT_TYPE::SD)
 		{
-			s_last_source = mountSourceInfo;
-			fsCmdBlock->data.mount_it = 0;
+			// This function is supposed to be called after an initial FSGetMountSource call => always returns FS_RESULT::END_ITERATION because we only have one SD Card
+			// It *might* causes issues if this function is called for getting the first MountSource (instead of "FSGetMountSource")
+			cemu_assert_suspicious();
+			return FS_RESULT::END_ITERATION;
+		}
+		else
+		{
+			cemu_assert_unimplemented();
 		}
 
-		fsCmdBlock->data.mount_it++;
+		return FS_RESULT::END_ITERATION;
+	}
 
-		// SD
-		if (mountSourceType == MOUNT_TYPE::SD && fsCmdBlock->data.mount_it == 1)
+	FS_RESULT FSGetMountSource(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, MOUNT_TYPE mountSourceType, FS_MOUNT_SOURCE* mountSourceInfo, FS_ERROR_MASK errMask)
+	{
+		// This implementation is simplified A LOT compared to what the Wii U is actually doing. On Cemu we expect to only have one mountable source (SD Card) anyway,
+		// so we can just hard code it. Other mount types are not (yet) supported.
+		if (mountSourceType == MOUNT_TYPE::SD)
 		{
 			mountSourceInfo->sourceType = 0;
 			strcpy(mountSourceInfo->path, "/sd");
 			return FS_RESULT::SUCCESS;
 		}
+		else
+		{
+			cemu_assert_unimplemented();
+		}
 
 		return FS_RESULT::END_ITERATION;
 	}
 
-	FS_RESULT FSGetMountSource(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, MOUNT_TYPE mountSourceType, FS_MOUNT_SOURCE* mountSourceInfo, FS_ERROR_MASK errMask)
-	{
-		return FSGetMountSourceNext(fsClient, fsCmdBlock, mountSourceType, mountSourceInfo, errMask);
-	}
-
 	bool _sdCard01Mounted = false;
 	bool _mlc01Mounted = false;
 
@@ -1399,7 +1406,7 @@ namespace coreinit
 		return __FSProcessAsyncResult(fsClient, fsCmdBlock, fsAsyncRet, errorMask);
 	}
 
-	FSA_RESULT __FSPrepareCmd_AppendFile(iosu::fsa::FSAShimBuffer* fsaShimBuffer, IOSDevHandle fsaHandle, uint32 fileHandle, uint32 size, uint32 count, uint32 uknParam)
+	FSA_RESULT __FSPrepareCmd_AppendFile(iosu::fsa::FSAShimBuffer* fsaShimBuffer, IOSDevHandle fsaHandle, uint32 size, uint32 count, uint32 fileHandle, uint32 uknParam)
 	{
 		if (fsaShimBuffer == nullptr)
 			return FSA_RESULT::INVALID_BUFFER;
@@ -1408,29 +1415,29 @@ namespace coreinit
 		fsaShimBuffer->operationType = (uint32)FSA_CMD_OPERATION_TYPE::APPENDFILE;
 
 		fsaShimBuffer->request.cmdAppendFile.fileHandle = fileHandle;
-		fsaShimBuffer->request.cmdAppendFile.count = size;
-		fsaShimBuffer->request.cmdAppendFile.size = count;
+		fsaShimBuffer->request.cmdAppendFile.count = count;
+		fsaShimBuffer->request.cmdAppendFile.size = size;
 		fsaShimBuffer->request.cmdAppendFile.uknParam = uknParam;
 
 		return FSA_RESULT::OK;
 	}
 
-	sint32 FSAppendFileAsync(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, uint32 fileHandle, uint32 size, uint32 count, uint32 errorMask, FSAsyncParamsNew_t* fsAsyncParams)
+	sint32 FSAppendFileAsync(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, uint32 size, uint32 count, uint32 fileHandle, uint32 errorMask, FSAsyncParamsNew_t* fsAsyncParams)
 	{
 		_FSCmdIntro();
-		FSA_RESULT prepareResult = __FSPrepareCmd_AppendFile(&fsCmdBlockBody->fsaShimBuffer, fsClientBody->iosuFSAHandle, fileHandle, size, count, 0);
+		FSA_RESULT prepareResult = __FSPrepareCmd_AppendFile(&fsCmdBlockBody->fsaShimBuffer, fsClientBody->iosuFSAHandle, size, count, fileHandle, 0);
 		if (prepareResult != FSA_RESULT::OK)
 			return (FSStatus)_FSAStatusToFSStatus(prepareResult);
 
 		__FSQueueCmd(&fsClientBody->fsCmdQueue, fsCmdBlockBody, RPLLoader_MakePPCCallable(export___FSQueueDefaultFinishFunc));
 		return (FSStatus)FS_RESULT::SUCCESS;
 	}
 
-	sint32 FSAppendFile(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, uint32 fileHandle, uint32 size, uint32 count, uint32 errorMask)
+	sint32 FSAppendFile(FSClient_t* fsClient, FSCmdBlock_t* fsCmdBlock, uint32 size, uint32 count, uint32 fileHandle,  uint32 errorMask)
 	{
 		StackAllocator<FSAsyncParamsNew_t> asyncParams;
 		__FSAsyncToSyncInit(fsClient, fsCmdBlock, asyncParams);
-		sint32 fsAsyncRet = FSAppendFileAsync(fsClient, fsCmdBlock, fileHandle, size, count, errorMask, asyncParams.GetPointer());
+		sint32 fsAsyncRet = FSAppendFileAsync(fsClient, fsCmdBlock, size, count, fileHandle, errorMask, asyncParams.GetPointer());
 		return __FSProcessAsyncResult(fsClient, fsCmdBlock, fsAsyncRet, errorMask);
 	}