FTPFS(4) FTPFS(4)
NAME
ftpfs - file transfer protocol (FTP) file system
SYNOPSIS
ftpfs [ -/dqnt ] [ -m mountpoint ] [ -a password ] [ -e ext
] [ -k keyspec ] [ -o os ] [ -r remoteroot ] system
DESCRIPTION
Ftpfs dials the TCP file transfer protocol (FTP) port, 21,
on system and mounts itself (see bind(2)) on mountpoint
(default /n/ftp) to provide access via FTP to files on the
remote machine. Ftpfs attempts to use FTP's `passive' mode
but falls back to using `active' mode if that fails. If
required by the remote machine, ftpfs will ask factotum(4)
for a key matching the pattern
proto=pass service=ftp server=system user? !password? keyspec
(If factotum does not have such a key, factotum will prompt
the user for one.)
The user names ftp and anonymous conventionally offer
guest/read-only access to machines. Anonymous FTP may be
called without using factotum by using the -a option and
specifying the password.
By default the file seen at the mount point is the user's
remote home directory if he has one. The option -/ forces
the mount point to correspond to the remote root. The
option -r forces the mount point to correspond to the remote
directory remoteroot.
To avoid seeing startup messages from the server use option
-q. To see all messages from the server use option -d.
Some systems will hangup an ftp connection that has no
activity for a given period. The -K option causes ftp to
send a NOP command every 15 seconds to attempt to keep the
connection open. This command can cause some servers to
hangup, so you'll have to feel your way.
The -t option causes ftpfs to negotiate TLS encryption with
the server.
To terminate the connection, unmount (see bind(1)) the mount
point.
Since there is no specified format for metadata retrieved in
response to an FTP directory request, ftpfs has to apply
heuristics to steer the interpretation. Sometimes, though
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rarely, these heuristics fail. The following options are
meant as last resorts to try to steer interpretation.
A major clue to the heuristics is the operating system at
the other end. Normally this can be determined automati-
cally using the FTP SYST command. However, in some cases
the server doesn't implement the SYST command. The -o
option will force the case by specifying the name of the
operating system. Known system types are: UNIX, SUN, TOPS,
Plan9, VM, VMS, MVS, NetWare, OS/2, TSO, and WINDOWS_NT.
Some systems and/or FTP servers return directory listings
that don't include the file extension. The -e option allows
the user to specify an extension to append to all remote
files (other than directories).
Finally, there are two FTP commands to retrieve the contents
of a directory, LIST and NLST. LIST is approximately equiv-
alent to `ls -l' and NLST to `ls'. Ftpfs normally uses
LIST. However, some FTP servers interpret LIST to mean,
give a wordy description of the file. Ftpfs normally
notices this and switches to using NLST. However, in some
rare cases, the user must force the use of NLST with the -n
option.
EXAMPLE
You want anonymous FTP access to the system
export.lcs.mit.edu. The first import(4) command is only
necessary if your machine does not have access to the
desired system, but another, called gateway in this example,
does.
import gateway /net
ftpfs -a yourname@yourmachine export.lcs.mit.edu
SOURCE
/sys/src/cmd/ip/ftpfs
SEE ALSO
bind(2)
BUGS
Symbolic links on remote Unix systems will always have mode
0777 and a length of 8.
After connecting to a TOPS-20 system, the mount point will
contain only one directory, usually /n/ftp/PS:<ANONYMOUS>.
However, walking to any valid directory on that machine will
succeed and cause that directory entry to appear under the
mount point.
Ftpfs caches files and directories. A directory will fall
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from the cache after 5 quiescent minutes or if the local
user changes the directory by writing or removing a file.
Otherwise, remote changes to the directory that occur after
the directory has been cached might not be immediately visi-
ble. Attempting to walk to directory/.flush.ftpfs will
flush directory from the cache, thus forcing ftpfs to re-
read it.
There is no way to issue the appropriate commands to handle
special synthetic FTP file types such as directories that
automatically return a tar of their contents.
Ftpfs makes copies in /tmp of files being transferred, so
its effects might not be immediate. If there is enough main
memory, you might want to run ramfs(4) first.
Filenames containing spaces will confuse ftpfs (and other
FTP clients).
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