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kernel/linux-imx6_3.14.28/Documentation/filesystems/adfs.txt 2.64 KB
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  Mount options for ADFS
  ----------------------
  
    uid=nnn	All files in the partition will be owned by
  		user id nnn.  Default 0 (root).
    gid=nnn	All files in the partition will be in group
  		nnn.  Default 0 (root).
    ownmask=nnn	The permission mask for ADFS 'owner' permissions
  		will be nnn.  Default 0700.
    othmask=nnn	The permission mask for ADFS 'other' permissions
  		will be nnn.  Default 0077.
    ftsuffix=n	When ftsuffix=0, no file type suffix will be applied.
  		When ftsuffix=1, a hexadecimal suffix corresponding to
  		the RISC OS file type will be added.  Default 0.
  
  Mapping of ADFS permissions to Linux permissions
  ------------------------------------------------
  
    ADFS permissions consist of the following:
  
  	Owner read
  	Owner write
  	Other read
  	Other write
  
    (In older versions, an 'execute' permission did exist, but this
     does not hold the same meaning as the Linux 'execute' permission
     and is now obsolete).
  
    The mapping is performed as follows:
  
  	Owner read				-> -r--r--r--
  	Owner write				-> --w--w---w
  	Owner read and filetype UnixExec	-> ---x--x--x
      These are then masked by ownmask, eg 700	-> -rwx------
  	Possible owner mode permissions		-> -rwx------
  
  	Other read				-> -r--r--r--
  	Other write				-> --w--w--w-
  	Other read and filetype UnixExec	-> ---x--x--x
      These are then masked by othmask, eg 077	-> ----rwxrwx
  	Possible other mode permissions		-> ----rwxrwx
  
    Hence, with the default masks, if a file is owner read/write, and
    not a UnixExec filetype, then the permissions will be:
  
  			-rw-------
  
    However, if the masks were ownmask=0770,othmask=0007, then this would
    be modified to:
  			-rw-rw----
  
    There is no restriction on what you can do with these masks.  You may
    wish that either read bits give read access to the file for all, but
    keep the default write protection (ownmask=0755,othmask=0577):
  
  			-rw-r--r--
  
    You can therefore tailor the permission translation to whatever you
    desire the permissions should be under Linux.
  
  RISC OS file type suffix
  ------------------------
  
    RISC OS file types are stored in bits 19..8 of the file load address.
  
    To enable non-RISC OS systems to be used to store files without losing
    file type information, a file naming convention was devised (initially
    for use with NFS) such that a hexadecimal suffix of the form ,xyz
    denoted the file type: e.g. BasicFile,ffb is a BASIC (0xffb) file.  This
    naming convention is now also used by RISC OS emulators such as RPCEmu.
  
    Mounting an ADFS disc with option ftsuffix=1 will cause appropriate file
    type suffixes to be appended to file names read from a directory.  If the
    ftsuffix option is zero or omitted, no file type suffixes will be added.