.\" Copyright (c) 2002 .\" Nate Lawson. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Neither the name of the author nor the names of any co-contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY Nate Lawson AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD: src/share/man/man4/targ.4,v 1.3.2.1 2003/02/18 22:07:11 njl Exp $ .\" .Dd November 15, 2002 .Dt TARG 4 .Os .Sh NAME .Nm targ .Nd SCSI target emulator driver .Sh SYNOPSIS .Cd device targ .Sh DESCRIPTION The .Nm driver provides an interface for usermode programs to emulate SCSI target devices. A sample program that emulates a disk drive (similar to .Xr da 4 ) can be found in .Pa /usr/share/examples/scsi_target . .Pp The .Nm driver supplies control devices, .Pa /dev/targ0 , .Pa /dev/targ1 , etc. If a device is already in use, .Xr open 2 will fail and .Va errno will be set to .Er EBUSY . After opening the device, the file descriptor must be bound to a specific bus/target/LUN and enabled to process CCBs using the .Dv TARGIOCENABLE ioctl. The process then uses .Xr write 2 to send CCBs to the SIM and .Xr poll 2 or .Xr kqueue 2 to see if responses are ready. Pointers to completed CCBs are returned via .Xr read 2 . Any data transfers requested by the user CCBs are done via zero-copy IO. .Sh IOCTLS The following .Xr ioctl 2 calls are defined in the header file .In bus/cam/scsi/scsi_targetio.h . .Bl -tag -width ".Dv TARGIOCDISABLE" .It Dv TARGIOCENABLE .Pq Vt "struct ioc_enable_lun" Enable target mode on the LUN specified by the following structure: .Bd -literal -offset indent 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; }; .Ed .Pp The selected path (bus), target, and LUN must not already be in use or .Er EADDRINUSE is returned. If .Va grp6_len or .Va grp7_len are non-zero, reception of vendor-specific commands is enabled. .It Dv TARGIOCDISABLE Disable target mode and abort all pending CCBs. The CCBs may optionally be read as they complete. .Dv TARGIOCENABLE can then be called to activate a different LUN. Multiple disable calls have no effect. The .Xr close 2 system call automatically disables target mode if enabled. .It Dv TARGIOCDEBUG .Pq Vt int Enables .Dv CAM_PERIPH debugging if the argument is non-zero, otherwise disables it. .El .Sh FILES .Bl -tag -width ".Pa /sys/bus/cam/scsi/scsi_target.c" -compact .It In bus/cam/scsi/scsi_targetio.h describes the usermode interface. .It Pa /sys/bus/cam/scsi/scsi_target.c is the driver source file. .It Pa /dev/targ* are the control devices. .El .Sh SEE ALSO .Pa /usr/share/examples/scsi_target , .Xr isp 4 , .Xr scsi 4 .Rs .%T "FreeBSD Target Information" .%U http://www.root.org/~nate/freebsd/ .Re .Sh AUTHORS .An -nosplit The .Nm driver first appeared in .Fx 3.0 and was written by .An Justin T. Gibbs . It was rewritten for .Fx 5.0 by .An Nate Lawson Aq Mt nate@root.org . .Sh BUGS Currently, only the .Xr isp 4 driver fully supports target mode.