Documentation/filesystems/adfs.txt

   1 Mount options for ADFS
   2 ----------------------
   3
   4   uid=nnn       All files in the partition will be owned by
   5                 user id nnn.  Default 0 (root).
   6   gid=nnn       All files in the partition will be in group
   7                 nnn.  Default 0 (root).
   8   ownmask=nnn   The permission mask for ADFS 'owner' permissions
   9                 will be nnn.  Default 0700.
  10   othmask=nnn   The permission mask for ADFS 'other' permissions
  11                 will be nnn.  Default 0077.
  12   ftsuffix=n    When ftsuffix=0, no file type suffix will be applied.
  13                 When ftsuffix=1, a hexadecimal suffix corresponding to
  14                 the RISC OS file type will be added.  Default 0.
  15
  16 Mapping of ADFS permissions to Linux permissions
  17 ------------------------------------------------
  18
  19   ADFS permissions consist of the following:
  20
  21         Owner read
  22         Owner write
  23         Other read
  24         Other write
  25
  26   (In older versions, an 'execute' permission did exist, but this
  27    does not hold the same meaning as the Linux 'execute' permission
  28    and is now obsolete).
  29
  30   The mapping is performed as follows:
  31
  32         Owner read                              -> -r--r--r--
  33         Owner write                             -> --w--w---w
  34         Owner read and filetype UnixExec        -> ---x--x--x
  35     These are then masked by ownmask, eg 700    -> -rwx------
  36         Possible owner mode permissions         -> -rwx------
  37
  38         Other read                              -> -r--r--r--
  39         Other write                             -> --w--w--w-
  40         Other read and filetype UnixExec        -> ---x--x--x
  41     These are then masked by othmask, eg 077    -> ----rwxrwx
  42         Possible other mode permissions         -> ----rwxrwx
  43
  44   Hence, with the default masks, if a file is owner read/write, and
  45   not a UnixExec filetype, then the permissions will be:
  46
  47                         -rw-------
  48
  49   However, if the masks were ownmask=0770,othmask=0007, then this would
  50   be modified to:
  51                         -rw-rw----
  52
  53   There is no restriction on what you can do with these masks.  You may
  54   wish that either read bits give read access to the file for all, but
  55   keep the default write protection (ownmask=0755,othmask=0577):
  56
  57                         -rw-r--r--
  58
  59   You can therefore tailor the permission translation to whatever you
  60   desire the permissions should be under Linux.
  61
  62 RISC OS file type suffix
  63 ------------------------
  64
  65   RISC OS file types are stored in bits 19..8 of the file load address.
  66
  67   To enable non-RISC OS systems to be used to store files without losing
  68   file type information, a file naming convention was devised (initially
  69   for use with NFS) such that a hexadecimal suffix of the form ,xyz
  70   denoted the file type: e.g. BasicFile,ffb is a BASIC (0xffb) file.  This
  71   naming convention is now also used by RISC OS emulators such as RPCEmu.
  72
  73   Mounting an ADFS disc with option ftsuffix=1 will cause appropriate file
  74   type suffixes to be appended to file names read from a directory.  If the
  75   ftsuffix option is zero or omitted, no file type suffixes will be added.