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