Ubuntu Manpage: scanbm- User scanning support daemon for scanbd / scanbd manager

NAME

       scanbm- User scanning support daemon for scanbd / scanbd manager

SYNOPSIS

       scanbm [-c configfile [-d[debuglevel] ] [-s] [-t device -a action ]

       scanbd -m [-c configfile [-d[debuglevel] ] [-s] [-t device -a action ]

DESCRIPTION

scanbm is a companion to scanbd, a scanner button monitoring daemon that can trigger
execution of scripts when a button is pressed.

scanbm is actually a (symbolic) link to scanbd and can be called as scanbm or scanbd -m.

scanbd (the scanner button daemon) opens and polls the scanner and therefore locks the
device. So no other application can access the device directly (open the /dev/..., or via
libusb, etc).

To enable scanning from applications, we use scanbm as a manager for scanbd. scanbm is a
"proxy" for saned to access the scanner from an application. scanbm listens for requests
on the saned network port. All applications therefore need to use the "net backend to
access a scanner.

If a scan request arrives to scanbm on the sane-port, scanbm requests the scanbd scanner
polling daemon to interrupt polling and to release the device by sending it a dbus-message
(default) or a posix-signal (SIGUSR1) (signal-mode). It then starts the real saned which
does the scanning and sends the data back to the requesting application. When the scanning
is done and saned exits, scanbm requests scanbd to restart the polling by sending a second
dbus-message (or the posix-signal SIGUSR2) and ends execution. The polling scanbd now re-
enables polling of the devices.

scanbm is meant to be started from inetd, xinetd or systemd. Unlike saned it does not
support stand-alone mode.

Note: Please note that the scanbm acts as a proxy to saned, all scanner applications must
be configured to use the sane "net" backend to access the scanner. Direct access will not
be possible.

OPTIONS

       -c configfile --config=configfile
              Use configfile instead of the default /etc/scanbd/scanbd.conf configuration file.

       -d[debuglevel] --debug[=debuglevel]
              turn debug mode on. If specified, set the debug level to debuglevel
              1 = error
              2 = warn
              3 = info
              4 - 7 = debug)

       -s --signal
              use signals SIGUSR1/ SIGUSR2 instead of dbus messages to request the polling scanbd
              to stop / restart polling

       -t device --trigger=device
              Trigger action for device (numerical)

       -a action --action=action
              action (numerical) to be triggered

SCANBD/SCANBM CONFIGURATION

       scanbd  and  scanbm are configured trough scanbd.conf (/etc/scanbd/scanbd.conf or the file
       pointed out by the -c <config-file> )

NETWORK SETUP FOR SCANBM

       scanbm must be setup very similar to the way saned must be setup.  Note  that  your  inetd
       must  support  IPv6 if you want to connect to scanbm over IPv6 ; xinetd, openbsd-inetd and
       systemd are known to support IPv6, check the documentation for your inetd daemon.

INETD CONFIGURATION

       For scanbm it is also necessary to add a configuration line to /etc/inetd.conf  just  like
       it is for saned.

       The configuration line normally looks like this:

              sane-port stream tcp nowait scanbd.scanbd /usr/sbin/scanbm scanbm

       However,  if  your  system uses tcpd(8) for additional security screening, you may want to
       disable saned access control by putting ``+'' in saned.conf (see saned(8) ) and use a line
       of the following form in /etc/inetd.conf instead:

              sane-port stream tcp nowait scanbd.scanbd /usr/sbin/tcpd /usr/sbin/scanbm

       Note  that  both  examples  assume that there is a scanbd group and a scanbd user.  If you
       follow this example, please make sure that the access permissions on  the  special  device
       are  set  such  that  scanbd and saned can access the scanner (the programs generally need
       read and write access to scanner devices).

       If xinetd is installed  on  your  system  instead  of  inetd  the  following  example  for
       xinetd.conf may be helpful:

              # default: off
              # description: The sane server accepts requests
              # for network access to a local scanner via the
              # network.
              service sane-port
              {
                 port        = 6566
                 socket_type = stream
                 wait        = no
                 user        = scanbd
                 group       = scanbd
                 server      = /usr/sbin/scanbm
                 server_args =
              }

       Finally, it is also necessary to add a line of the following form to /etc/services:

              sane-port 6566/tcp # SANE network scanner daemon

       The  official  IANA  short name for port 6566 is "sane-port". The older name "sane" is now
       deprecated.

       scanbm does not do access control, but it relies on the access control done by saned.

AUTHOR

       Louis Lagendijk