AUSMT stands for Auto-Update System Modification Technology. AUSMT enables
patching of webOS system safely, handling the situations like OTA updates
etc.

This modified AUSMT is used by patchmanager in SailfishOS to perform system
files, just like with Preware on webOS.

General information:

  The AUSMT scripts can be called via the package postinst/prerm scripts,
  scripts. Since patches have to be installed inside 
  /usr/share/patchmanager/patches, the scripts only need one parameter 
  which is the name of the directory holding the patches to be installed 
  into the system. The structure of the directory can be seen below.

Directory structure:

  # This is the structure of the patch dir, any of these can be present,
  # i.e. not all are needed. The AUSMT script will install what it finds. 

  unified_diff.patch    # The patch file in unified diff format
  packages_cache.list   # Cache file that speads up the md5sum fetching
  patch.json            # Metadata used in patchmanager to provide information about the patch