.TH twoftpd-xfer 1
.SH NAME
twoftpd-xfer \- TwoFTPD file transfer back-end.
.SH SYNOPSIS
.B twoftpd-xfer
.SH DESCRIPTION
.B twoftpd-xfer
reads FTP request from the network and executes file
transfers based on those requests.
Before doing anything,
.B twoftpd-xfer
changes directory to the authenticated user's home directory, changes
the root directory to that directory, and drops all root priviledges.
.SH ENVIRONMENT
.TP
.B AUTHENTICATED
If set (typically by
.B twoftpd-auth
after successfully completing authentication), the startup banner will
use code
.IR 230 ,
indicating that authentication was successful.  Otherwise, the startup
banner will use code
.IR 220 ,
which is the normal initial connection banner.
.TP
.B BANNER
If set, the contents of this variable will be sent as extra responses when
the server starts.
.TP
.B CHROOT
If set, change the root directory to the user's home directory through
the OS chroot syscall.
.TP
.B CONNECT_TIMEOUT
The maximum number of seconds to wait for a data channel connection to
complete.  If not set, it defaults to the value of
.BR $TIMEOUT .
.TP
.B GID
Numerical group ID number to change to at program startup.
.TP
.B GIDS
Optional comma-seperated list of numerical group IDs to set up as the
supplementary group IDs.
.TP
.B GROUP
Group name to use in long listings for files owned by
.BR $GID .
If not set, defaults to
.IR mygroup .
.TP
.B HOME
Directory to switch to on program startup.
.TP
.B LOCKHOME
If set (and neither
.B CHROOT
nor
.B SOFTCHROOT
are set), all accesses to files and paths outside of
.B HOME
will be forbidden.
.TP
.B LOGREQUESTS
If set, all requests from the client will be logged.
.TP
.B LOGRESPONSES
If set, all responses to the client (after login) will be logged.
.TP
.B MESSAGEFILE
If set, the contents this file will be automatically sent as extra
responses to the client whenever the server enters a directory
(including at startup).
.TP
.B NODOTFILES
If set, all listings will exclude all files starting with a period,
and it will not be possible to do any file access (including storing
or retrieving) to any file starting with a period.  This may be useful
for anonymous FTP servers.
.TP
.B SESSION_TIMEOUT
The maximum number of seconds to allow a single session to last.
.TP
.B SOFTCHROOT
If set, and
.B CHROOT
is not set, the server emulates the effect of a chroot without
actually effecting a chroot.  This eliminates the system-enforced
barrier provided by the chroot, but allows for things like symlinks
outside of the home directory.
.TP
.B TCPLOCALIP
The IP to use when creating PASV connections.
Normally, this is set by
.BR tcpserver .
.TP
.B TCPREMOTEIP
The source IP to use when creating PORT connections.
Normally, this is set by
.BR tcpserver .
.TP
.B TIMEOUT
The maximum number of seconds to wait for command input or
connections.
.TP
.B UID
Numerical user ID number to change to at program startup.
.TP
.B USER
Owner name to use in long listings for files owned by
.BR $UID .
.SH NOTES
You will need to set the umask to an appropriate value before running
this program.
.P
The
.B twoftpd-anon
program functions identically to this program, with the exception of
having no file modification capabilities.
The
.B twoftpd-drop
program is a similarly restricted program, that can only create new
files (no overwriting, modifying, or listing existing files).