ExeFS: Difference between revisions
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ExeFS or Executable Filesystem, is the part of the CXI, which is executed when the CXI is run. | === Overview === | ||
ExeFS or Executable Filesystem, is the part of the CXI, which is executed when the CXI is run. | |||
The ExeFS usually contains one or more of the following files: | |||
* .code Contains the code binary, which can be optionally reverse-LZSS compressed via an exheader flag. | * .code Contains the code binary, which can be optionally reverse-LZSS compressed via an exheader flag. | ||
* [[logo]] Contains distribution licensing Binary data. | * [[logo|.logo]] Contains distribution licensing Binary data. | ||
* [[File Formats|banner]] Contains the banner which homemenu uses for this CXI. | * [[File Formats|.banner]] Contains the banner which homemenu uses for this CXI. | ||
* [[SMDH|icon]] Contains the icon which homemenu displays for this CXI. | * [[SMDH|.icon]] Contains the icon which homemenu displays for this CXI. | ||
=== | === Format === | ||
The ExeFS header is 0x200 bytes long and follows this structure: | The ExeFS header is 0x200 bytes long and follows this simple structure: | ||
{| class="wikitable" border="1" | {| class="wikitable" border="1" | ||
| Line 17: | Line 19: | ||
|- | |- | ||
| 0x00 | | 0x00 | ||
| | | 0x80 | ||
| | | File headers (8 headers maximum, 16 bytes each) | ||
|- | |- | ||
| | | 0x80 | ||
| | | 0x80 | ||
| Reserved | | Reserved | ||
|- | |- | ||
| | | 0x100 | ||
| | | 0x100 | ||
| | | File hashes (8 hashes maximum, 32 bytes each, one for each header) | ||
| | |} | ||
==== File headers ==== | |||
| | There are a maximum of 8 file headers in the ExeFS format, which have the following structure: | ||
{| class="wikitable" border="1" | |||
|- | |- | ||
! START | |||
! SIZE | |||
! DESCRIPTION | |||
|- | |- | ||
| | | 0x0 | ||
| | | 0x8 | ||
| | | File name | ||
|- | |- | ||
| | | 0x8 | ||
| | | 0x4 | ||
| | | File offset | ||
|- | |- | ||
| 0xC | |||
| 0x4 | |||
| File size | |||
|} | |} | ||
==== File hashes ==== | |||
Each file header has a corresponding file hash, which is the SHA256 hash calculated over the entire file contents. | |||
<nowiki>* Offsets are non-inclusive of the header's size(0x200 bytes).</nowiki> | <nowiki>* Offsets are non-inclusive of the header's size(0x200 bytes).</nowiki> | ||
Revision as of 19:00, 8 June 2012
Overview
ExeFS or Executable Filesystem, is the part of the CXI, which is executed when the CXI is run.
The ExeFS usually contains one or more of the following files:
- .code Contains the code binary, which can be optionally reverse-LZSS compressed via an exheader flag.
- .logo Contains distribution licensing Binary data.
- .banner Contains the banner which homemenu uses for this CXI.
- .icon Contains the icon which homemenu displays for this CXI.
Format
The ExeFS header is 0x200 bytes long and follows this simple structure:
| START | SIZE | DESCRIPTION |
|---|---|---|
| 0x00 | 0x80 | File headers (8 headers maximum, 16 bytes each) |
| 0x80 | 0x80 | Reserved |
| 0x100 | 0x100 | File hashes (8 hashes maximum, 32 bytes each, one for each header) |
File headers
There are a maximum of 8 file headers in the ExeFS format, which have the following structure:
| START | SIZE | DESCRIPTION |
|---|---|---|
| 0x0 | 0x8 | File name |
| 0x8 | 0x4 | File offset |
| 0xC | 0x4 | File size |
File hashes
Each file header has a corresponding file hash, which is the SHA256 hash calculated over the entire file contents.
* Offsets are non-inclusive of the header's size(0x200 bytes).
** The 'Logo' is not a compulsory part of ExeFS, so an ExeFS without a 'Logo', will have these entries of the header filled with zeros. .