From 001442fd8ac39022061911fd9a5782bef601ae4c Mon Sep 17 00:00:00 2001
From: Edoardo Lolletti <edoardo762@gmail.com>
Date: Sun, 28 Jul 2024 11:03:31 +0200
Subject: [PATCH] Add sd cluster size check

If a sd is present, and its cluster size is bigger than 32k, abort installing
---
 arm9/src/main.c    |  7 +++++++
 arm9/src/storage.c | 29 +++++++++++++++++++++++++++++
 arm9/src/storage.h |  2 ++
 3 files changed, 38 insertions(+)

diff --git a/arm9/src/main.c b/arm9/src/main.c
index c3d6a4a..d9228a9 100644
--- a/arm9/src/main.c
+++ b/arm9/src/main.c
@@ -200,6 +200,13 @@ int main(int argc, char **argv)
 		messageBox("fatInitDefault()...\x1B[31mFailed\n\x1B[47m");
 	}
 
+	u32 clusterSize = getClusterSizeForPartition("sd:/");
+	if(clusterSize > 32768)
+	{
+		messageBox("Sd card cluster size is too large");
+		return 0;
+	}
+
 	//setup nand access
 	if (!fatMountSimple("nand", &io_dsi_nand))
 	{
diff --git a/arm9/src/storage.c b/arm9/src/storage.c
index 31c728f..6f38508 100644
--- a/arm9/src/storage.c
+++ b/arm9/src/storage.c
@@ -226,3 +226,32 @@ bool removeIfExists(const char* path)
 {
 	return remove(path) == 0 || errno == ENOENT;
 }
+
+// Filesystem type
+typedef enum {FS_UNKNOWN, FS_FAT12, FS_FAT16, FS_FAT32} FS_TYPE;
+//trimmed down PARTITION struct from libfat internals
+typedef struct {
+	const void* disc;
+	void*                cache;
+	// Info about the partition
+	FS_TYPE               filesysType;
+	uint64_t              totalSize;
+	sec_t                 rootDirStart;
+	uint32_t              rootDirCluster;
+	uint32_t              numberOfSectors;
+	sec_t                 dataStart;
+	uint32_t              bytesPerSector;
+	uint32_t              sectorsPerCluster;
+	uint32_t              bytesPerCluster;
+	uint32_t              fsInfoSector;
+} PARTITION;
+
+extern PARTITION* _FAT_partition_getPartitionFromPath(const char* path);
+
+u32 getClusterSizeForPartition(const char* path)
+{
+	PARTITION* p = _FAT_partition_getPartitionFromPath(path);
+	if(!p)
+		return 0;
+	return p->bytesPerCluster;
+}
diff --git a/arm9/src/storage.h b/arm9/src/storage.h
index 73d8a93..d166460 100644
--- a/arm9/src/storage.h
+++ b/arm9/src/storage.h
@@ -25,6 +25,8 @@ bool safeCreateDir(const char* path);
 //Files and directories
 bool removeIfExists(const char* path);
 
+u32 getClusterSizeForPartition(const char* path);
+
 #ifdef __cplusplus
 }
 #endif