Difference between revisions of "ExeFS"

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=== Overview ===
+
ExeFS or Executable Filesystem contains information related to the executable program, and is the part of the [[NCCH#CXI|CXI]] format.  
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:
 
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|.logo]] Contains distribution licensing Binary data.
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* [[logo|logo]] Contains distribution licensing Binary data.
* [[File Formats|.banner]] Contains the banner which homemenu uses for this CXI.
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* [[File Formats|banner]] Contains the banner which homemenu uses for this CXI.
* [[SMDH|.icon]] Contains the icon which homemenu displays for this CXI.
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* [[SMDH|icon]] Contains the icon which homemenu displays for this CXI.
  
 
=== Format ===
 
=== Format ===
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{| class="wikitable" border="1"
 
{| class="wikitable" border="1"
 
|-
 
|-
START
+
Start
SIZE
+
Size
DESCRIPTION
+
Description
 
|-
 
|-
 
|  0x00
 
|  0x00
0x80
+
0xa0
|  File headers (8 headers maximum, 16 bytes each)
+
|  File headers (10 headers maximum, 16 bytes each)
 
|-
 
|-
0x80
+
0xa0
0x80
+
0x20
 
|  Reserved
 
|  Reserved
 
|-
 
|-
0x100
+
0xc0
0x100
+
0x140
|  File hashes (8 hashes maximum, 32 bytes each, one for each header)
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|  File hashes (10 hashes maximum, 32 bytes each, one for each header)
 
|}
 
|}
 +
 +
File hashes are stored in reverse order, i.e. the hash at offset 0x1E0 corresponds to the first ExeFS section.
  
 
==== File headers ====
 
==== File headers ====
There are a maximum of 8 file headers in the ExeFS format, which have the following structure:
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There are a maximum of 10 file headers in the ExeFS format. (This maximum number of file headers is disputable, with makerom indicating a maximum of 8 sections and makecia indicating a maximum of 10. From a non-SDK point of view, the ExeFS header format can hold no more than 10 file headers within the currently define size of 0x200 bytes.) The file headers have the following structure:
  
 
{| class="wikitable" border="1"
 
{| class="wikitable" border="1"
 
|-
 
|-
START
+
Start
SIZE
+
Size
DESCRIPTION
+
Description
 
|-
 
|-
 
|  0x0
 
|  0x0
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|  File size
 
|  File size
 
|}
 
|}
 +
 +
File offsets are non-inclusive of the header's size (0x200 bytes). Also, file headers which are not used are filled with all zeros.
  
 
==== File hashes ====
 
==== File hashes ====
 
Each file header has a corresponding file hash, which is the SHA256 hash calculated over the entire file contents.
 
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>** 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.</nowiki>
 
.
 

Latest revision as of 20:33, 20 March 2016

ExeFS or Executable Filesystem contains information related to the executable program, and is the part of the CXI format.

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[edit]

The ExeFS header is 0x200 bytes long and follows this simple structure:

Start Size Description
0x00 0xa0 File headers (10 headers maximum, 16 bytes each)
0xa0 0x20 Reserved
0xc0 0x140 File hashes (10 hashes maximum, 32 bytes each, one for each header)

File hashes are stored in reverse order, i.e. the hash at offset 0x1E0 corresponds to the first ExeFS section.

File headers[edit]

There are a maximum of 10 file headers in the ExeFS format. (This maximum number of file headers is disputable, with makerom indicating a maximum of 8 sections and makecia indicating a maximum of 10. From a non-SDK point of view, the ExeFS header format can hold no more than 10 file headers within the currently define size of 0x200 bytes.) The file headers have the following structure:

Start Size Description
0x0 0x8 File name
0x8 0x4 File offset
0xC 0x4 File size

File offsets are non-inclusive of the header's size (0x200 bytes). Also, file headers which are not used are filled with all zeros.

File hashes[edit]

Each file header has a corresponding file hash, which is the SHA256 hash calculated over the entire file contents.