| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 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. |