NAME

       targ — SCSI target emulator driver

SYNOPSIS

       To compile this driver into the kernel, place the following line in your kernel configuration file:

             device targ

DESCRIPTION

       The  targ  driver  provides  an interface for usermode programs to emulate SCSI target devices.  A sample
       program that emulates a disk drive (similar to da(4)) can be found in /usr/share/examples/scsi_target.

       The targ driver supplies the control device /dev/targ.  After opening the  device,  the  file  descriptor
       must  be  bound  to  a specific bus/target/LUN and enabled to process CCBs using the TARGIOCENABLE ioctl.
       The process then uses write(2) to send CCBs to the SIM and poll(2) or kqueue(2) to see if  responses  are
       ready.   Pointers  to  completed CCBs are returned via read(2).  Any data transfers requested by the user
       CCBs are done via zero-copy IO.

IOCTLS

       The following ioctl(2) calls are defined in the header file <cam/scsi/scsi_targetio.h>.

       TARGIOCENABLE   (struct ioc_enable_lun) Enable  target  mode  on  the  LUN  specified  by  the  following
                       structure:

                             struct ioc_enable_lun {
                                     path_id_t       path_id;
                                     target_id_t     target_id;
                                     lun_id_t        lun_id;
                                     int             grp6_len;
                                     int             grp7_len;
                             };

                       The  selected  path  (bus),  target,  and LUN must not already be in use or EADDRINUSE is
                       returned.  If grp6_len or grp7_len are non-zero, reception of vendor-specific commands is
                       enabled.

       TARGIOCDISABLE  Disable target mode and abort all pending CCBs.  The CCBs may optionally be read as  they
                       complete.   TARGIOCENABLE  can  then  be  called  to  activate a different LUN.  Multiple
                       disable calls have no effect.  The close(2) system  call  automatically  disables  target
                       mode if enabled.

       TARGIOCDEBUG    (int) Enables CAM_PERIPH debugging if the argument is non-zero, otherwise disables it.

FILES

       <cam/scsi/scsi_targetio.h>   describes the usermode interface.
       /sys/cam/scsi/scsi_target.c  is the driver source file.
       /dev/targ                    is the control device.

SEE ALSO

       /usr/share/examples/scsi_target, ahc(4), isp(4), scsi(4)

       FreeBSD Target Information, http://www.root.org/~nate/freebsd/.

AUTHORS

       The  targ  driver first appeared in FreeBSD 3.0 and was written by Justin T. Gibbs.  It was rewritten for
       FreeBSD 5.0 by Nate Lawson <nate@root.org>.

BUGS

       Currently, only the ahc(4) and isp(4) drivers fully support target mode.

       The ahc(4) driver does not support tagged queuing in target mode.

Debian                                          December 13, 2011                                        TARG(4)