Difference between revisions of "FST"
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| − | The Filesystem Table, or FST, is a file present in Wii U disk images and downloaded content that describes the folders and files contained in the | + | The Filesystem Table, or FST, is a file present in Wii U disk images and downloaded content that describes the folders and files contained in the title. |
It seems to be based on the Wii's FST format, but an extra header/cluster section was added. | It seems to be based on the Wii's FST format, but an extra header/cluster section was added. | ||
| Line 20: | Line 20: | ||
! Field !! Size !! Offset !! Description | ! Field !! Size !! Offset !! Description | ||
|- | |- | ||
| − | |Magic || 4 || 0 || always "FST" and a null byte | + | |Magic || 4 || 0 || always 0x46535400 ("FST" and a null byte) |
|- | |- | ||
|Secondary header size || 4 || 4 || (not sure) | |Secondary header size || 4 || 4 || (not sure) | ||
| Line 45: | Line 45: | ||
|Name Offset || 4 || 0 || Offset in bytes of the name of the file from the start of the nametable | |Name Offset || 4 || 0 || Offset in bytes of the name of the file from the start of the nametable | ||
|- | |- | ||
| − | |Offset || 4 || 4 || Offset | + | |Offset || 4 || 4 || Offset of the file in its storage cluster: usually in sectors (multiply by 32 for byte offset); may be in bytes if the 0x4 bit in flags is set |
|- | |- | ||
|Size || 4 || 8 || Size of the file in bytes | |Size || 4 || 8 || Size of the file in bytes | ||
|- | |- | ||
| − | | Storage cluster index || | + | | Flags || 2 || 12 || 0x4: offset is in bytes, not sectors; 0x440: data contains SHA-1 hash |
| + | |- | ||
| + | | Storage cluster index || 2 || 14 || an index to the list of secondary headers. Additionally, for downloaded content, same as the content ID (an index into the title metadata's list of files.) | ||
|} | |} | ||
| − | If the top bits of the name offset is set (&0xff000000), then this entry is a directory | + | If the top bits of the name offset is set (&0xff000000), then this entry is a directory. |
| − | In this case, the size corresponds to the number of entries this directory contains. | + | In this case, the size corresponds to the number of entries this directory contains, and the offset field corresponds to the parent directory's offset. |
== Nametable == | == Nametable == | ||
| Line 61: | Line 63: | ||
== External Links == | == External Links == | ||
| + | |||
| + | https://code.google.com/p/cdecrypt/source/browse/trunk/main.cpp - Crediar's CDecrypt tool that can parse FSTs from downloaded content | ||
https://github.com/CarlKenner/dolphin/blob/WiiU/Source/Core/DiscIO/FileSystemWiiU.cpp - A fork of Dolphin by CarlKenner that can read WiiU disk images. | https://github.com/CarlKenner/dolphin/blob/WiiU/Source/Core/DiscIO/FileSystemWiiU.cpp - A fork of Dolphin by CarlKenner that can read WiiU disk images. | ||
http://blog.delroth.net/2011/06/reading-wii-discs-with-python/ - some information on the Wii's FST format | http://blog.delroth.net/2011/06/reading-wii-discs-with-python/ - some information on the Wii's FST format | ||
Revision as of 21:07, 21 June 2015
The Filesystem Table, or FST, is a file present in Wii U disk images and downloaded content that describes the folders and files contained in the title.
It seems to be based on the Wii's FST format, but an extra header/cluster section was added.
All numbers are big-endian.
The file is composed of four sections:
- the main header
- a number of secondary headers describing storage clusters
- a number of file and directory entries, beginning with the root directory
- a table of null-terminated names
Main Header
Size: 0x20 bytes
| Field | Size | Offset | Description |
|---|---|---|---|
| Magic | 4 | 0 | always 0x46535400 ("FST" and a null byte) |
| Secondary header size | 4 | 4 | (not sure) |
| Secondary header count | 4 | 8 | Number of secondary headers in the FST |
Secondary header
Each of these entries describe the position of data on disk. For downloaded content, each corresponds to one entry from the TMD.
Size: 0x20 each
File/Directory entry
Each of these represents a file or a directory.
Size: 0x10 each
| Field | Size | Offset | Description |
|---|---|---|---|
| Name Offset | 4 | 0 | Offset in bytes of the name of the file from the start of the nametable |
| Offset | 4 | 4 | Offset of the file in its storage cluster: usually in sectors (multiply by 32 for byte offset); may be in bytes if the 0x4 bit in flags is set |
| Size | 4 | 8 | Size of the file in bytes |
| Flags | 2 | 12 | 0x4: offset is in bytes, not sectors; 0x440: data contains SHA-1 hash |
| Storage cluster index | 2 | 14 | an index to the list of secondary headers. Additionally, for downloaded content, same as the content ID (an index into the title metadata's list of files.) |
If the top bits of the name offset is set (&0xff000000), then this entry is a directory.
In this case, the size corresponds to the number of entries this directory contains, and the offset field corresponds to the parent directory's offset.
Nametable
Table of null-terminated filenames.
External Links
https://code.google.com/p/cdecrypt/source/browse/trunk/main.cpp - Crediar's CDecrypt tool that can parse FSTs from downloaded content
https://github.com/CarlKenner/dolphin/blob/WiiU/Source/Core/DiscIO/FileSystemWiiU.cpp - A fork of Dolphin by CarlKenner that can read WiiU disk images.
http://blog.delroth.net/2011/06/reading-wii-discs-with-python/ - some information on the Wii's FST format