fdmount(1)

💖 fdmount(1) — Floppy Disk Mount Utility 💖

okay so bestie, we're in section 1 of the General Commands Manual today, and the star of the show is fdmount from the fdutils fam. sit down, grab a snack, this one's got options, daemons, and floppy disks. yes, actual floppy disks. vintage queen behavior. 💾✨

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🌸 Note 🌸

ngl, this manpage was automatically generated from fdutils's texinfo documentation, and the process is only approximative, so some stuff — cross-references, footnotes, indices — straight up gets lost in translation. like, those items have no appropriate representation in the manpage format, periodt. also, only the items specific to each command got translated, and the general info about fdutils got dropped in the manpage version. so the author strongly advises you to use the original texinfo doc. it's giving "the real one is better, trust".

• To generate a printable copy from the texinfo doc, run:

./configure; make dvi; dvips fdutils.dvi

• To generate a HTML copy, run:

./configure; make html

A pre-made HTML can be found at: http://www.tux.org/pub/knaff/fdutils

• To generate an info copy (browsable using emacs' info mode), run:

./configure; make info

the texinfo doc looks most pretty when printed or as HTML 🎀. indeed, in the info version certain examples are difficult to read because of the quoting conventions used in info. iykyk.

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✨ Description ✨

here's the whole vibe in one block, keep up:

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. detective mode activated 🔍

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. she's versatile, okay?

it also checks whether the disk is write protected, in which case it is mounted read-only. safety first, bestie 💅

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. default queen behavior fr fr.

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. no cap.

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. yes the parenthetical question mark is in the original. we're all confused together 🫶

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🎀 Options 🎀

• -l, --list — list all known drives with their symbolic name, type, and mount status. a little drive census, love that for us.
• -d, --daemon — run in daemon mode (see below). she works in the background now 💼
• --detach — runs daemon in background, and detaches it from its tty. messages produced after the fork are logged to syslog. independent icon.
• -p file
• --pidfile file

dumps the process id of the daemon to file. this makes killing the daemon easier: kill -9 \cat file`` — dramatic but efficient 💀

• -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). math girlies rise.

• -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. picky but fair.

• -r, --readonly — mount the disk read-only. this is automatically assumed if the disk is write protected. she's not letting you touch anything and honestly? valid.
• -s, --sync — mount with the SYNC option.
• --nosync — mounts without the SYNC option, even when running as daemon. chaotic but your call.
• --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. gaslighting your own mtab, iconic.
• -h, --help — show short parameter description. when you just need a lil summary 🥺

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🔒 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. no shortcuts bestie.

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. ⚠️ that's a real warning, not a vibe. she said what she said.

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👑 Daemon mode 👑

in daemon mode, the specified drive is periodically checked and if a disk is inserted, it is automatically mounted. she does it herself now ✨

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 section 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. 🙈 everyone can see your floppy, sorry bestie.

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😭 Diagnostics 😭

these are the messages she might yell at you. buckle up.

• 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. shockingly straightforward.
• 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. yayyy we did it 🎉

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🐛 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. 💡 constant main character energy from the LED.
• some newer filesystem types, such as vfat are not yet supported.

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🦋 See Also 🦋

• Fdutils' texinfo doc

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and that's the whole page, bestie!! mwah 💖 this lil beauty comes from fdutils-5.6, dated 27Jan21, and it's the fdmount(1) page — go forth and mount your floppies responsibly, drink water, and don't rely on suid root security. love u, byeeeee 🎀💅✨