From 2d36460a02015b1647acdebf5268f9d8e8c43e51 Mon Sep 17 00:00:00 2001
From: d0k3 <tore.anon@gmail.com>
Date: Mon, 30 Oct 2017 14:46:37 +0100
Subject: [PATCH] Virtual VRAM drive, based on TAR

---
 source/filesys/fsdrive.c |   2 +
 source/filesys/fsdrive.h |  14 +++--
 source/game/3dsx.h       |   2 +-
 source/godmode.c         |   2 +-
 source/system/tar.c      |  89 ++++++++++++++++++++++++++++
 source/system/tar.h      |  35 +++++++++++
 source/system/vram0.h    |  31 ++++++++++
 source/utils/scripting.c |   2 +-
 source/virtual/vgame.c   |   5 +-
 source/virtual/vgame.h   |   2 +-
 source/virtual/virtual.c |  22 +++++--
 source/virtual/virtual.h |   5 +-
 source/virtual/vvram.c   | 123 +++++++++++++++++++++++++++++++++++++++
 source/virtual/vvram.h   |  12 ++++
 14 files changed, 326 insertions(+), 20 deletions(-)
 create mode 100644 source/system/tar.c
 create mode 100644 source/system/tar.h
 create mode 100644 source/system/vram0.h
 create mode 100644 source/virtual/vvram.c
 create mode 100644 source/virtual/vvram.h

diff --git a/source/filesys/fsdrive.c b/source/filesys/fsdrive.c
index 7d12095..02cad0e 100644
--- a/source/filesys/fsdrive.c
+++ b/source/filesys/fsdrive.c
@@ -55,6 +55,8 @@ int DriveType(const char* path) {
             type = DRV_VIRTUAL | DRV_GAME | DRV_IMAGE;
         } else if (vsrc == VRT_CART) {
             type = DRV_VIRTUAL | DRV_CART;
+        } else if (vsrc == VRT_VRAM) {
+            type = DRV_VIRTUAL | DRV_VRAM;
         } 
     }
     
diff --git a/source/filesys/fsdrive.h b/source/filesys/fsdrive.h
index d0652d3..eb52d8d 100644
--- a/source/filesys/fsdrive.h
+++ b/source/filesys/fsdrive.h
@@ -5,7 +5,7 @@
 
 #define NORM_FS  10
 #define IMGN_FS  3 // image normal filesystems 
-#define VIRT_FS  12
+#define VIRT_FS  13
 
 // primary drive types
 #define DRV_UNKNOWN     (0<<0)
@@ -23,10 +23,11 @@
 #define DRV_MEMORY      (1UL<<10)
 #define DRV_GAME        (1UL<<11)
 #define DRV_CART        (1UL<<12)
-#define DRV_ALIAS       (1UL<<13)
-#define DRV_BONUS       (1UL<<14)
-#define DRV_SEARCH      (1UL<<15)
-#define DRV_STDFAT      (1UL<<16) // standard FAT drive without limitations
+#define DRV_VRAM        (1UL<<13)
+#define DRV_ALIAS       (1UL<<14)
+#define DRV_BONUS       (1UL<<15)
+#define DRV_SEARCH      (1UL<<16)
+#define DRV_STDFAT      (1UL<<17) // standard FAT drive without limitations
 
 #define FS_DRVNAME \
         "SDCARD", \
@@ -36,11 +37,12 @@
         "GAMECART", \
         "GAME IMAGE", "AESKEYDB IMAGE", "TICKET.DB IMAGE", \
         "MEMORY VIRTUAL", \
+        "VRAM VIRTUAL", \
         "NAND XORPADS", \
         "LAST SEARCH" \
         
 #define FS_DRVNUM \
-    "0:", "1:", "2:", "3:", "A:", "S:", "4:", "5:", "6:", "B:", "E:", "7:", "8:", "9:", "I:", "C:", "G:", "K:", "T:", "M:", "X:", "Z:"
+    "0:", "1:", "2:", "3:", "A:", "S:", "4:", "5:", "6:", "B:", "E:", "7:", "8:", "9:", "I:", "C:", "G:", "K:", "T:", "M:", "V:", "X:", "Z:"
 
 /** Function to identify the type of a drive **/
 int DriveType(const char* path);
diff --git a/source/game/3dsx.h b/source/game/3dsx.h
index f8b5f36..6e748d2 100644
--- a/source/game/3dsx.h
+++ b/source/game/3dsx.h
@@ -19,5 +19,5 @@ typedef struct {
     u32 size_bss;
     u32 offset_smdh;
     u32 size_smdh;
-    u32 size_romfs_lv3;
+    u32 offset_romfs_lv3;
 } __attribute__((packed)) ThreedsxHeader;
diff --git a/source/godmode.c b/source/godmode.c
index 5e42cfe..4c04bbe 100644
--- a/source/godmode.c
+++ b/source/godmode.c
@@ -235,7 +235,7 @@ void DrawUserInterface(const char* curr_path, DirEntry* curr_entry, u32 curr_pan
             ((drvtype & DRV_SDCARD) ? "SD" : (drvtype & DRV_RAMDRIVE) ? "RAMdrive" : (drvtype & DRV_GAME) ? "Game" :
             (drvtype & DRV_SYSNAND) ? "SysNAND" : (drvtype & DRV_EMUNAND) ? "EmuNAND" : (drvtype & DRV_IMAGE) ? "Image" :
             (drvtype & DRV_XORPAD) ? "XORpad" : (drvtype & DRV_MEMORY) ? "Memory" : (drvtype & DRV_ALIAS) ? "Alias" :
-            (drvtype & DRV_CART) ? "Gamecart" : (drvtype & DRV_SEARCH) ? "Search" : ""),
+            (drvtype & DRV_CART) ? "Gamecart" : (drvtype & DRV_VRAM) ? "VRAM" : (drvtype & DRV_SEARCH) ? "Search" : ""),
             ((drvtype & DRV_FAT) ? " FAT" : (drvtype & DRV_VIRTUAL) ? " Virtual" : ""));
         ResizeString(tempstr, drvstr, len_info / FONT_WIDTH_EXT, 8, false);
     } else {
diff --git a/source/system/tar.c b/source/system/tar.c
new file mode 100644
index 0000000..1b316a9
--- /dev/null
+++ b/source/system/tar.c
@@ -0,0 +1,89 @@
+#include "tar.h"
+
+
+u64 ReadAsciiOctal(char* num, u32 len) {
+    u64 res = 0;
+    
+    if ((num[len-1] != '\0') && (num[len-1] != ' '))
+        return (u64) -1;
+    
+    for (u32 i = 0; i < (len-1); i++) {
+        res <<= 3;
+        if ((num[i] >= '0') && (num[i] < '8')) res |= (num[i] - '0');
+        else return (u64) -1;
+    }
+    
+    return res;
+}
+
+u32 ValidateTarHeader(void* tardata, void* tardata_end) {
+    TarHeader* tar = tardata;
+    
+    // available space
+    if ((u8*) tardata_end < (u8*) tardata + sizeof(TarHeader))
+        return 1;
+    
+    // filename prefix is not supported here
+    if (*(tar->fname_prefix)) return 1;
+    
+    // ustar magic
+    if (strncmp(tar->magic, USTAR_MAGIC, 5) != 0)
+        return 1;
+    
+    // check filesize
+    u64 fsize_max = ((u8*) tardata_end - (u8*) tardata) - sizeof(TarHeader);
+    if (ReadAsciiOctal(tar->fsize, 12) > fsize_max)
+        return 1;
+    
+    // type can only be standard file or dir
+    if ((tar->ftype != '0') && (tar->ftype != '5'))
+        return 1;
+    
+    // checksum
+    u8* data = (u8*) tardata;
+    u64 checksum = 0;
+    for (u32 i = 0; i < sizeof(TarHeader); i++)
+        checksum += ((i < 148) || (i >= 156)) ? data[i] : (u64) ' ';
+    if (checksum != ReadAsciiOctal(tar->checksum, 7))
+        return 1;
+    
+    return 0;
+}
+
+void* GetTarFileInfo(void* tardata, char* fname, u64* fsize, bool* is_dir) {
+    // this assumes a valid TAR header
+    TarHeader* tar = tardata;
+    
+    if (fname) snprintf(fname, 101, "%.100s", tar->fname);
+    if (fsize) *fsize = ReadAsciiOctal(tar->fsize, 12);
+    if (is_dir) *is_dir = (tar->ftype == '5');
+    
+    return (void*) (tar + 1);
+}
+
+void* NextTarEntry(void* tardata, void* tardata_end) {
+    // this assumes a valid TAR header
+    TarHeader* tar = tardata;
+    u8* data = (u8*) tardata;
+    u64 fsize = ReadAsciiOctal(tar->fsize, 12);
+    
+    data += sizeof(TarHeader) + align(fsize, 512);
+    if (ValidateTarHeader(data, tardata_end) != 0)
+        return NULL;
+    
+    return data;
+}
+
+void* FindTarFileInfo(void* tardata, void* tardata_end, const char* fname, u64* fsize, bool* is_dir) {
+    while (tardata && (tardata < tardata_end)) {
+        TarHeader* tar = tardata;
+        
+        if (ValidateTarHeader(tardata, tardata_end) != 0) break;
+        ShowPrompt(false, "%s\n%s", tar->fname, fname);
+        if ((strncasecmp(tar->fname, fname, 100) == 0) && (tar->ftype == '0'))
+            return GetTarFileInfo(tardata, NULL, fsize, is_dir);
+        tardata = ((u8*) tardata) + sizeof(TarHeader) + align(ReadAsciiOctal(tar->fsize, 12), 512);
+    }
+    
+    return NULL;
+}
diff --git a/source/system/tar.h b/source/system/tar.h
new file mode 100644
index 0000000..740801c
--- /dev/null
+++ b/source/system/tar.h
@@ -0,0 +1,35 @@
+#pragma once
+
+#include "common.h"
+
+#define USTAR_MAGIC "ustar"
+
+
+// see: https://en.wikipedia.org/wiki/Tar_(computing)
+// all numeric values in ASCII / octal
+typedef struct {
+    char fname[100];
+    char fmode[8];
+    char owner_id[8];
+    char group_id[8];
+    char fsize[12];
+    char last_modified[12];
+    char checksum[8];
+    char ftype;
+    char link_name[100];
+    // ustar extension
+    char magic[6]; // "ustar"
+    char version[2]; // "00"
+    char owner_name[32];
+    char group_name[32];
+    char dev_major[8];
+    char dev_minor[8];
+    char fname_prefix[155];
+    char unused[12];
+} __attribute__((packed)) TarHeader;
+
+
+u32 ValidateTarHeader(void* tardata, void* tardata_end);
+void* GetTarFileInfo(void* tardata, char* fname, u64* fsize, bool* is_dir);
+void* NextTarEntry(void* tardata, void* tardata_end);
+void* FindTarFileInfo(void* tardata, void* tardata_end, const char* fname, u64* fsize, bool* is_dir);
diff --git a/source/system/vram0.h b/source/system/vram0.h
new file mode 100644
index 0000000..b94a27a
--- /dev/null
+++ b/source/system/vram0.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include "common.h"
+#include "tar.h"
+
+
+#define VRAM0_OFFSET    0x18000000
+#define VRAM0_LIMIT     0x00300000
+
+#define TARDATA         ((void*) VRAM0_OFFSET)
+#define TARDATA_(off)   ((void*) (u32) (VRAM0_OFFSET + (off)))
+#define TARDATA_END     TARDATA_(VRAM0_LIMIT)
+
+
+#define CheckVram0Tar() \
+    (ValidateTarHeader(TARDATA, TARDATA_END) == 0)
+
+#define FirstVTarEntry() \
+    TARDATA
+    
+#define OffsetVTarEntry(off) \
+    TARDATA_(off)
+
+#define NextVTarEntry(tardata) \
+    NextTarEntry(tardata, TARDATA_END)
+    
+#define GetVTarFileInfo(tardata, fname, fsize, is_dir) \
+    GetTarFileInfo(tardata, fname, fsize, is_dir)
+    
+#define FindVTarFileInfo(fname, fsize, is_dir) \
+    FindTarFileInfo(TARDATA, TARDATA_END, fname, fsize, is_dir)
diff --git a/source/utils/scripting.c b/source/utils/scripting.c
index 34e7250..947de19 100644
--- a/source/utils/scripting.c
+++ b/source/utils/scripting.c
@@ -827,7 +827,7 @@ bool ValidateText(const char* text, u32 len) {
         char c = text[i];
         if ((c == '\r') && ((i+1) < len) && (text[i+1] != '\n')) return false; // CR without LF
         if ((c < 0x20) && (c != '\t') && (c != '\r') && (c != '\n')) return false; // illegal control char
-        if ((c == 0x7F) || (c == 0xFF)) return false; // other illegal char
+        if (c == 0xFF) return false; // other illegal char
     }
     return true;
 }
diff --git a/source/virtual/vgame.c b/source/virtual/vgame.c
index 8010bfc..4a7e60e 100644
--- a/source/virtual/vgame.c
+++ b/source/virtual/vgame.c
@@ -664,7 +664,7 @@ u64 InitVGameDrive(void) { // prerequisite: game file mounted as image
     return type;
 }
 
-u32 CheckVGameDrive(void) {
+u64 CheckVGameDrive(void) {
     if (vgame_type != GetMountState()) vgame_type = 0; // very basic sanity check
     return vgame_type;
 }
@@ -799,7 +799,6 @@ bool OpenVGameDir(VirtualDir* vdir, VirtualFile* ventry) {
 
 bool ReadVGameDirLv3(VirtualFile* vfile, VirtualDir* vdir) {
     vfile->name[0] = '\0';
-    BuildLv3Index(&lv3idx, romfslv3);
     vfile->flags = VFLAG_LV3 | VFLAG_READONLY;
     vfile->keyslot = ((offset_ncch != (u64) -1) && NCCH_ENCRYPTED(ncch)) ? 
         0x2C : 0xFF; // actual keyslot may be different
@@ -1038,7 +1037,7 @@ bool GetVGameFilename(char* name, const VirtualFile* vfile, u32 n_chars) {
 
 bool MatchVGameFilename(const char* name, const VirtualFile* vfile, u32 n_chars) {
     if (vfile->flags & VFLAG_LV3) {
-         char lv3_name[256];
+        char lv3_name[256];
         if (!GetVGameLv3Filename(lv3_name, vfile, 256)) return false;
         return (strncasecmp(name, lv3_name, n_chars) == 0);
     } else if (vfile->flags & VFLAG_NITRO) {
diff --git a/source/virtual/vgame.h b/source/virtual/vgame.h
index 63362fe..c6fb5b8 100644
--- a/source/virtual/vgame.h
+++ b/source/virtual/vgame.h
@@ -5,7 +5,7 @@
 #include "virtual.h"
 
 u64 InitVGameDrive(void);
-u32 CheckVGameDrive(void);
+u64 CheckVGameDrive(void);
 
 bool OpenVGameDir(VirtualDir* vdir, VirtualFile* ventry);
 bool ReadVGameDir(VirtualFile* vfile, VirtualDir* vdir);
diff --git a/source/virtual/virtual.c b/source/virtual/virtual.c
index 48f3c53..16ccdd4 100644
--- a/source/virtual/virtual.c
+++ b/source/virtual/virtual.c
@@ -5,6 +5,7 @@
 #include "vtickdb.h"
 #include "vkeydb.h"
 #include "vcart.h"
+#include "vvram.h"
 
 typedef struct {
     char drv_letter;
@@ -31,6 +32,8 @@ bool CheckVirtualDrive(const char* path) {
     u32 virtual_src = GetVirtualSource(path);
     if (virtual_src & (VRT_EMUNAND|VRT_IMGNAND))
         return CheckVNandDrive(virtual_src); // check virtual NAND drive for EmuNAND / ImgNAND
+    else if (virtual_src & VRT_VRAM)
+        return CheckVVramDrive();
     else if (virtual_src & VRT_GAME)
         return CheckVGameDrive();
     else if (virtual_src & VRT_TICKDB)
@@ -55,6 +58,8 @@ bool ReadVirtualDir(VirtualFile* vfile, VirtualDir* vdir) {
         ret = ReadVKeyDbDir(vfile, vdir);
     } else if (virtual_src & VRT_CART) {
         ret = ReadVCartDir(vfile, vdir);
+    } else if (virtual_src & VRT_VRAM) {
+        ret = ReadVVramDir(vfile, vdir);
     }
     vfile->flags |= virtual_src; // add source flag
     return ret;
@@ -111,8 +116,9 @@ bool GetVirtualFile(VirtualFile* vfile, const char* path) {
         if (!(vdir.flags & VFLAG_LV3)) { // standard method
             while (true) {
                 if (!ReadVirtualDir(vfile, &vdir)) return false;
-                if ((!(vfile->flags & VRT_GAME) && (strncasecmp(name, vfile->name, 32) == 0)) ||
-                    ((vfile->flags & VRT_GAME) && MatchVGameFilename(name, vfile, 256)))
+                if ((!(vfile->flags & (VRT_GAME|VRT_VRAM)) && (strncasecmp(name, vfile->name, 32) == 0)) ||
+                    ((vfile->flags & VRT_GAME) && MatchVGameFilename(name, vfile, 256)) ||
+                    ((vfile->flags & VRT_VRAM) && MatchVVramFilename(name, vfile)))
                     break; // entry found
             }
         } else { // use lv3 hashes for quicker search
@@ -132,8 +138,10 @@ bool GetVirtualDir(VirtualDir* vdir, const char* path) {
 }
 
 bool GetVirtualFilename(char* name, const VirtualFile* vfile, u32 n_chars) {
-    if (!(vfile->flags & VRT_GAME)) strncpy(name, vfile->name, n_chars);
-    else if (!GetVGameFilename(name, vfile, n_chars)) return false;
+    if (vfile->flags & VRT_GAME) return GetVGameFilename(name, vfile, n_chars);
+    else if (vfile->flags & VRT_VRAM) return GetVVramFilename(name, vfile);
+    
+    strncpy(name, vfile->name, n_chars);
     return true;
 }
 
@@ -157,6 +165,8 @@ int ReadVirtualFile(const VirtualFile* vfile, void* buffer, u64 offset, u64 coun
         return ReadVKeyDbFile(vfile, buffer, offset, count);
     } else if (vfile->flags & VRT_CART) {
         return ReadVCartFile(vfile, buffer, offset, count);
+    } else if (vfile->flags & VRT_VRAM) {
+        return ReadVVramFile(vfile, buffer, offset, count);
     }
     
     return -1;
@@ -176,7 +186,7 @@ int WriteVirtualFile(const VirtualFile* vfile, const void* buffer, u64 offset, u
         return WriteVNandFile(vfile, buffer, offset, count);
     } else if (vfile->flags & VRT_MEMORY) {
         return WriteVMemFile(vfile, buffer, offset, count);
-    } // no write support for virtual game / tickdb / keydb / cart files
+    } // no write support for virtual game / tickdb / keydb / cart / vram files
     
     return -1;
 }
@@ -208,5 +218,7 @@ u64 GetVirtualDriveSize(const char* path) {
         return GetVKeyDbDriveSize();
     else if (virtual_src & VRT_CART)
         return GetVCartDriveSize();
+    else if (virtual_src & VRT_VRAM)
+        return GetVVramDriveSize();
     return 0;
 }
diff --git a/source/virtual/virtual.h b/source/virtual/virtual.h
index 5a958e4..5bc826e 100644
--- a/source/virtual/virtual.h
+++ b/source/virtual/virtual.h
@@ -12,8 +12,9 @@
 #define VRT_TICKDB  (1UL<<6)
 #define VRT_KEYDB   (1UL<<7)
 #define VRT_CART    (1UL<<8)
+#define VRT_VRAM    (1UL<<9)
 
-#define VRT_SOURCE  (VRT_SYSNAND|VRT_EMUNAND|VRT_IMGNAND|VRT_XORPAD|VRT_MEMORY|VRT_GAME|VRT_TICKDB|VRT_KEYDB|VRT_CART)
+#define VRT_SOURCE  (VRT_SYSNAND|VRT_EMUNAND|VRT_IMGNAND|VRT_XORPAD|VRT_MEMORY|VRT_GAME|VRT_TICKDB|VRT_KEYDB|VRT_CART|VRT_VRAM)
 
 #define VFLAG_DIR       (1UL<<10)
 #define VFLAG_ROOT      (1UL<<11)
@@ -23,7 +24,7 @@
 
 
 #define VRT_DRIVES  {'S', VRT_SYSNAND}, {'E', VRT_EMUNAND}, {'I', VRT_IMGNAND}, {'X', VRT_XORPAD }, \
-                    {'M', VRT_MEMORY}, {'G', VRT_GAME}, {'K', VRT_KEYDB}, {'T', VRT_TICKDB}, {'C', VRT_CART}
+                    {'M', VRT_MEMORY}, {'G', VRT_GAME}, {'K', VRT_KEYDB}, {'T', VRT_TICKDB}, {'C', VRT_CART}, {'V', VRT_VRAM}
 
 // virtual file flag (subject to change):
 // bits 0...3  : reserved for NAND virtual sources and info
diff --git a/source/virtual/vvram.c b/source/virtual/vvram.c
new file mode 100644
index 0000000..28d31d6
--- /dev/null
+++ b/source/virtual/vvram.c
@@ -0,0 +1,123 @@
+#include "vvram.h"
+#include "vram0.h"
+
+
+bool SplitTarFName(char* tar_fname, char** dir, char** name) {
+    u32 len = strnlen(tar_fname, 100 + 1);
+    if (!len || (len == 101)) return false;
+    
+    // remove trailing slash
+    if (tar_fname[len-1] == '/') tar_fname[--len] = '\0';
+    
+    // find last slash
+    char* slash = strrchr(tar_fname, '/');
+    
+    // relative root dir entry
+    if (!slash) {
+        *name = tar_fname;
+        *dir = NULL;
+    } else {
+        *slash = '\0';
+        *name = slash + 1;
+        *dir = tar_fname;
+    }
+    
+    return true;
+}
+
+
+bool CheckVVramDrive(void) {
+    return CheckVram0Tar();
+}
+
+bool ReadVVramDir(VirtualFile* vfile, VirtualDir* vdir) {
+    vfile->name[0] = '\0';
+    vfile->flags = VFLAG_READONLY;
+    vfile->keyslot = 0xFF;
+    
+    
+    // get current dir name
+    char curr_dir[100 + 1];
+    if (vdir->offset == (u64) -1) return false; // end of the dir?
+    else if (!vdir->offset) *curr_dir = '\0'; // relative root?
+    else {
+        // vdir->offset is offset of dir entry + 0x200
+        TarHeader* tar = (TarHeader*) OffsetVTarEntry(vdir->offset - 0x200);
+        strncpy(curr_dir, tar->fname, 100);
+        u32 len = strnlen(curr_dir, 100 + 1);
+        if (len == 101) return false; // path error
+        if (curr_dir[len-1] == '/') curr_dir[len-1] = '\0';
+    }
+    
+    
+    // using vdir index to signify the position limits us to 1TiB TARs
+    void* tardata = NULL;
+    if (vdir->index < 0) tardata = FirstVTarEntry();
+    else tardata = NextVTarEntry(OffsetVTarEntry(vdir->index << 9));
+    
+    do {
+        TarHeader* tar = (TarHeader*) tardata;
+        char tar_fname[100 + 1];
+        char *name, *dir;
+        
+        strncpy(tar_fname, tar->fname, 100);
+        if (!SplitTarFName(tar_fname, &dir, &name)) return false;
+        if ((!dir && !*curr_dir) || (dir && (strncmp(dir, curr_dir, 100) == 0))) break;
+    } while ((tardata = NextVTarEntry(tardata)));
+    
+    // match found?
+    if (tardata) {
+        u64 fsize;
+        bool is_dir;
+        void* fdata = GetVTarFileInfo(tardata, NULL, &fsize, &is_dir);
+        
+        vfile->offset = (u32) fdata - VRAM0_OFFSET;
+        vfile->size = fsize;
+        if (is_dir) vfile->flags |= VFLAG_DIR;
+        
+        vdir->index = (vfile->offset >> 9) - 1;
+    } else { // not found
+        vdir->offset = (u64) -1;
+        return false;
+    }
+    
+    
+    return true;
+}
+
+int ReadVVramFile(const VirtualFile* vfile, void* buffer, u64 offset, u64 count) {
+    if (vfile->flags & VFLAG_DIR) return -1;
+    void* fdata = (u8*) VRAM0_OFFSET + vfile->offset;
+    
+    // range checks in virtual.c
+    memcpy(buffer, (u8*) fdata + offset, count);
+    return 0;
+}
+
+bool GetVVramFilename(char* name, const VirtualFile* vfile) {
+    void* tardata = OffsetVTarEntry(vfile->offset - 0x200);
+    TarHeader* tar = (TarHeader*) tardata;
+    char tar_fname[100 + 1];
+    char *name_tmp, *dir;
+    
+    strncpy(tar_fname, tar->fname, 100);
+    if (!SplitTarFName(tar_fname, &dir, &name_tmp)) return false;
+    strncpy(name, name_tmp, 100);
+    
+    return true;
+}
+
+bool MatchVVramFilename(const char* name, const VirtualFile* vfile) {
+    void* tardata = OffsetVTarEntry(vfile->offset - 0x200);
+    TarHeader* tar = (TarHeader*) tardata;
+    char tar_fname[100 + 1];
+    char *name_tmp, *dir;
+    
+    strncpy(tar_fname, tar->fname, 100);
+    if (!SplitTarFName(tar_fname, &dir, &name_tmp)) return false;
+    return (strncasecmp(name, name_tmp, 100) == 0);
+}
+
+u64 GetVVramDriveSize(void) {
+    return VRAM0_LIMIT;
+}
diff --git a/source/virtual/vvram.h b/source/virtual/vvram.h
new file mode 100644
index 0000000..6fb7c00
--- /dev/null
+++ b/source/virtual/vvram.h
@@ -0,0 +1,12 @@
+#include "common.h"
+#include "virtual.h"
+
+bool CheckVVramDrive(void);
+
+bool ReadVVramDir(VirtualFile* vfile, VirtualDir* vdir);
+int ReadVVramFile(const VirtualFile* vfile, void* buffer, u64 offset, u64 count);
+
+bool GetVVramFilename(char* name, const VirtualFile* vfile);
+bool MatchVVramFilename(const char* name, const VirtualFile* vfile);
+
+u64 GetVVramDriveSize(void);