fdmount
=======

     fdmount [-l] [--list] [-d] [--daemon] [--detach]
     [-i INTERVAL] [--interval INTERVAL] [-o MOUNT-OPTIONS]
     [-r] [-readonly] [-s] [--sync] [--nosync] [--nodev]
     [--nosuid] [--noexec] [-f] [--force] [-h] [--help]
     [DRIVENAME] [MOUNTPOINT]

     fdumount [-f] [--force] [DRIVENAME]

     fdlist

     fdmountd [-i INTERVAL] [--interval INTERVAL] [-r]
     [-readonly] [-s] [--sync] [--nosync] [--nodev]
     [--nosuid] [--noexec] [--help] [DRIVENAME] [MOUNTPOINT]]

The fdmount program mounts a floppy disk in the specified drive. It tries to figure out the exact format and filesystem type of the disk from data in the disk's boot sector or super block and the auto-detected track layout.

Currently, fdmount supports the filesystems minix, ext, ext2, xia, and msdos, and includes special support for disks formatted by the 2M utility for MS-DOS.

It also checks whether the disk is write protected, in which case it is mounted read-only.

The symbolic DRIVENAME is (currently) one of fd[0-7], corresponding to the special device files /dev/fd[0-7]. If DRIVENAME is not specified, fd0 is assumed.

The disk is mounted on the directory MOUNTPOINT, if specified, or on /fd[0-7].  In either case, the mount point must be an existing, writable directory.

Due to a bug in the floppy driver (?), the polling interval (-i flag) must be longer than the spindown offset. Thus you need to do (for example) floppycontrol --spindown 99 before starting fdmountd in daemon mode

Options
-------

-l --LIST
     List all known drives with their symbolic name, type, and mount status.

-d --DAEMON
     Run in daemon mode (see below).

--detach
     Runs daemon in background, and detaches it from its tty. Messages produced after the fork are logged to syslog.

-p FILE
--pidfile FILE

     Dumps the process id of the daemon to FILE. This makes killing the daemon easier: kill -9 `cat FILE`

-i INTERVAL
--interval INTERVAL
     Set the polling interval for daemon mode. The unit for INTERVAL is 0.1 seconds, the default value is 10 (i.e. 1 second).

-o OPTIONS
--options OPTIONS
     Sets filesystem-specific options. So far, these are only available for DOS and Ext2 disks. The following DOS options are supported: check, conv, dotsOK, debug, fat, quiet, blocksize.  The following Ext2 options are supported: check, errors, grpid, bsdgroups, nogrpid, sysvgroups, bsddf, minixdf, resgid, debug, nocheck.  When running as a daemon, options not applying to the disk that is inserted (because of its filesystem type) are not passed to mount.

-r --READONLY
     Mount the disk read-only. This is automatically assumed if the disk is write protected.

-s --SYNC
     Mount with the SYNC option.

--nosync
     Mounts without the SYNC option, even when running as daemon.

--nodev
     Mount with the NODEV option. Ignored for msdos filesystems, otherwise always set for non-root users.

--nosuid
     Mount with the NOSUID option. Ignored for msdos filesystems, otherwise always set for non-root users.

--noexec
     Mount with the NOEXEC option.

-f --FORCE
     Attempt a mount or unmount operation even /etc/mtab says that the drive is already mounted, or not mounted, respectively. This option is useful if /etc/mtab got out of sync with the actual state for some reason.

-h --HELP
     Show short parameter description

Security
--------

When mounting on the default mount point, the mount points' owner is set to the current user, and the access flags according to the user's umask. For a specified mountpoint, owner and permissions are left unchanged. Default mount points are called /fd0, /fd1, ... , /fd7.

The user running fdmount must have read access to the floppy device for read only mounts, and read/write access for read/write mounts.

Fdmount can be run suid root, allowing users to mount floppy disks. The following restrictions are placed upon non-root users:

  * If a mountpoint is specified explicitly, it must be owned by the user.

  * A user may only unmount a disk if the mount point is owned by the user, or if it the disk has been mounted by the same user.

  * Non-msdos disks are automatically mounted with the nodev and nosuid flags set.

However, do not rely on fdmount being secure at the moment.

Daemon mode
-----------

In daemon mode, the specified drive is periodically checked and if a disk is inserted, it is automatically mounted.

When the disk is removed, it is automatically unmounted.  However, it is recommended to unmount the disk manually before removing it. In order to limit corruption, disks are mounted with the SYNC option when running in daemon mode, unless the --nosync flag is given.

Note that this mode has some potential drawbacks:

  * Some floppy drives have to move the drive head physically in order to reset the disk change signal. It is strongly recommended not to use daemon mode with these drives.  See floppycontrol, for details.

  * If a disk does not contain a filesystem (e.g. a tar archive), the mount attempt may slow down initial access.

  * As fdmount cannot identify the user trying to use the disk drive, there is no way to protect privacy. Disks are always mounted with public access permissions set.

Diagnostics
-----------

error opening device NAME

error reading boot/super block
     fdmount failed to read the first 1K of the disk. The disk might be damaged, unformatted, or it may have a format which is unsupported by the FDC or the Linux kernel.

unknown filesystem type
     No magic number of any of the supported filesystems (see above) could be identified.

sorry, can't figure out format (FS filesystem)
     The size of the filesystem on the disk is incompatible with the track layout detected by the kernel and an integer number of tracks. This may occur if the filesystem uses only part of the disk, or the track layout was detected incorrectly by the kernel.

failed to mount FS> <SIZEK-disk
     The actual mount system call failed.

failed to unmount
     The actual unmount system call failed.

cannot create lock file /etc/mtab~
     If /etc/mtab~ exists, you should probably delete it. Otherwise, check permissions.

Can't access MOUNTPOINT
     Most probably, the default or specified mount point does not exist. Use mkdir.

MOUNTPOINT is not a directory
     The mountpoint is not a directory.

not owner of MOUNTPOINT
     Non-root users must own the directory specified as mount point. (This does not apply for the default mount points, /fd[0-3].)

No write permission to MOUNTPOINT
     Non-root users must have write permission on the mount point directory.

Not owner of mounted directory: UID=UID
     Non-root users cannot unmount if the mount point is owned (i.e. the disk was mounted) by another user.

invalid drive name
     Valid drive names are fd0, fd1, etc.

drive NAME does not exist
     The drive does not exist physically, is unknown to the Linux kernel, or is an unknown type.

Drive NAME is mounted already
     Trying to mount a drive which appears to be mounted already.  Use the --force option if you think this is wrong.

Drive NAME is not mounted
     Trying to unmount a drive which does not appear to be mounted.  Use the --force option if you think this is wrong.

ioctl(...) failed
     If this occurs with the FDGETDRVTYP or FDGETDRVSTAT, ioctl's you should probably update your Linux kernel.

mounted FS SIZE-disk (OPTIONS)
     Success message.

Bugs
----

  * Fdmount should be more flexible about drive names and default mount points (currently hard coded).

  * Probably not very secure yet (when running suid root). Untested with ext and xia filesystems.

  * Can't specify filesystem type and disk layout explicitly.

  * In daemon mode, the drive light stays on all the time.

  * Some newer filesystem types, such as vfat are not yet supported.