psypkg

Unpack, list and mount Psychonauts .pkg archives. Only the uncompressed version is currently supported, because I only have access to such files with my Steam copy of Psychonauts.

Basic usage:

psypkg.py list <archive>                 - list contens of .pkg archive
psypkg.py unpack <archive>               - extract .pkg archive
psypkg.py mount <archive> <mount-point>  - mount archive as read-only file system

The mount command depends on the llfuse Python package. If it's not available the rest is still working.

This script is compatible with Python 2.7 and 3 (tested with 2.7.5 and 3.3.2).

File Format

I used this description of the file format to implement this script. Here follows a summary of the file format.

There are many doubled file names in the PsychonautsData2.pkg file distributed with Psychonauts for Steam. I guess the later file records are updates on the earlier ones?

For these file entries the second occurance will overwrite the first when unpacking. When the archive is mounted as a file system name conflict resolution is a bit different. In this case ~number is added between the file name and the extension. number is the first number that doesn't produce a confict.

┌────────────────────────────────┐
│                                │
│  Header                        │
│                                │
│    file magic ("ZPKG")         │
│    version                     │
│    file data offset            │
│    number of files             │
│    unknown data offset         │
│    ?                           │
│    name directory offset       │
│    file type directory offset  │
│    zero-padding                │
│                                │
├────────────────────────────────┤
│                                │
│  File Records                  │
│                                │
│ ┌────────────────────────────┐ │
│ │                            │ │
│ │  Record                    │ │
│ │                            │ │
│ │    null                    │ │
│ │    file type offset        │ │
│ │    null                    │ │
│ │    file name offset        │ │
│ │    file data offset        │ │
│ │    file data size          │ │
│ │                            │ │
│ └────────────────────────────┘ │
│                                │
│  ...                           │
│                                │
├────────────────────────────────┤
│                                │
│  ???                           │
│                                │
├────────────────────────────────┤
│                                │
│  Name Directory                │
│                                │
├────────────────────────────────┤
│                                │
│  File Type Directory           │
│                                │
├────────────────────────────────┤
│                                │
│  File Data                     │
│                                │
└────────────────────────────────┘

ZSTR is a zero-terminated string. All values are encoded in little endian byte order.

Size  Type        Description
 512  Header      archive header
16*N  Record[N]   file records
   ?  ?           unknown data
   ?  ZSTR[*]     name directory: sequence of zero-terminated strings
   ?  ZSTR[*]     file type directory: sequence of zero-terminated strings
   ?  uint8_t[*]  file data

Header

Offset  Size  Type          Description
     0     4  char[4]       file magic ("ZPKG")
     4     4  uint32_t      version (1)
     8     4  uint32_t      file data offset
    12     4  uint32_t      number of files
    16     4  uint32_t      directory records offset
    20     4  uint32_t      number od directory records
    24     4  uint32_t      name directory offset
    28     4  uint32_t      file type directory offset
    32   480  uint8_t[480]  zero-padding (maybe reversed for use in version >1?)

File Record

Offset  Size  Type          Description
     0     1  uint8_t       null (0)
     1     2  uint16_t      file type offset (relative to file type direectory offset)
     3     1  uint8_t       null (0)
     4     4  uint32_t      file name offset (relative to name direectory offset)
     8     4  uint32_t      file data offset
    12     4  uint32_t      file data size

Directory Record

Offset  Size  Type          Description
     0     1  char          one character of a directory name
     1     1  uint8_t       null (0)
     2     2  uint16_t      ?
     4     2  uint16_t      ?
     6     2  uint16_t      record id (incremental from 1)
     8     2  uint16_t      start file index (inclusive)
    10     2  uint16_t      end file index (exclusive)

Related Projects

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unvpk: extract, list, check and mount Valve .vpk archives
u4pak: unpack, list and mount Unreal Engine 4 .pak archives
t2fbq: unpack, list and mount Trine 2 .fbq archives

BSD License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.