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| -rw-r--r-- | Documentation/filesystems/adfs.txt | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/Documentation/filesystems/adfs.txt b/Documentation/filesystems/adfs.txt new file mode 100644 index 000000000..594976635 --- /dev/null +++ b/Documentation/filesystems/adfs.txt @@ -0,0 +1,75 @@ +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. |