TARG(4)                FreeBSD Kernel Interfaces Manual                TARG(4)

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.

FreeBSD 13.1-RELEASE-p6        December 13, 2011       FreeBSD 13.1-RELEASE-p6