1.\" Copyright (c) 2002 2.\" Nate Lawson. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Neither the name of the author nor the names of any co-contributors 10.\" may be used to endorse or promote products derived from this software 11.\" without specific prior written permission. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY Nate Lawson AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd November 15, 2002 28.Dt TARG 4 29.Os 30.Sh NAME 31.Nm targ 32.Nd SCSI target emulator driver 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following line in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device targ" 39.Ed 40.Sh DESCRIPTION 41The 42.Nm 43driver provides an interface for usermode programs to emulate SCSI target 44devices. 45A sample program that emulates a disk drive (similar to 46.Xr da 4 ) 47can be found in 48.Pa /usr/share/examples/scsi_target . 49.Pp 50The 51.Nm 52driver supplies control devices, 53.Pa /dev/targ0 , 54.Pa /dev/targ1 , 55etc. 56If a device is already in use, 57.Xr open 2 58will fail and 59.Va errno 60will be set to 61.Er EBUSY . 62After opening the device, the file descriptor must be bound to a 63specific bus/target/LUN and enabled to process CCBs using the 64.Dv TARGIOCENABLE 65ioctl. 66The process then uses 67.Xr write 2 68to send CCBs to the SIM and 69.Xr poll 2 70or 71.Xr kqueue 2 72to see if responses are ready. 73Pointers to completed CCBs are returned via 74.Xr read 2 . 75Any data transfers requested by the user CCBs are done via zero-copy IO. 76.Sh IOCTLS 77The following 78.Xr ioctl 2 79calls are defined in the header file 80.In cam/scsi/scsi_targetio.h . 81.Bl -tag -width ".Dv TARGIOCDISABLE" 82.It Dv TARGIOCENABLE 83.Pq Vt "struct ioc_enable_lun" 84Enable target mode on the LUN specified by the following structure: 85.Bd -literal -offset indent 86struct ioc_enable_lun { 87 path_id_t path_id; 88 target_id_t target_id; 89 lun_id_t lun_id; 90 int grp6_len; 91 int grp7_len; 92}; 93.Ed 94.Pp 95The selected path (bus), target, and LUN must not already be in use or 96.Er EADDRINUSE 97is returned. 98If 99.Va grp6_len 100or 101.Va grp7_len 102are non-zero, reception of vendor-specific commands 103is enabled. 104.It Dv TARGIOCDISABLE 105Disable target mode and abort all pending CCBs. 106The CCBs may optionally be read as they complete. 107.Dv TARGIOCENABLE 108can then be called to activate a different LUN. 109Multiple disable calls have no effect. 110The 111.Xr close 2 112system call automatically disables target mode if enabled. 113.It Dv TARGIOCDEBUG 114.Pq Vt int 115Enables 116.Dv CAM_PERIPH 117debugging if the argument is non-zero, otherwise disables 118it. 119.El 120.Sh FILES 121.Bl -tag -width ".Pa /sys/cam/scsi/scsi_target.c" -compact 122.It In cam/scsi/scsi_targetio.h 123describes the usermode interface. 124.It Pa /sys/cam/scsi/scsi_target.c 125is the driver source file. 126.It Pa /dev/targ* 127are the control devices. 128.El 129.Sh SEE ALSO 130.Pa /usr/share/examples/scsi_target , 131.Xr ahc 4 , 132.Xr isp 4 , 133.Xr scsi 4 134.Rs 135.%T "FreeBSD Target Information" 136.%U http://www.root.org/~nate/freebsd/ 137.Re 138.Sh AUTHORS 139.An -nosplit 140The 141.Nm 142driver first appeared in 143.Fx 3.0 144and was written by 145.An Justin T. Gibbs . 146It was rewritten 147for 148.Fx 5.0 149by 150.An Nate Lawson Aq nate@root.org . 151.Sh BUGS 152Currently, only the 153.Xr ahc 4 154and 155.Xr isp 4 156drivers fully support target mode. 157.Pp 158The 159.Xr ahc 4 160driver does not support tagged queuing in target mode. 161