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.Dd December 13, 2011 26.Dt TARG 4 27.Os 28.Sh NAME 29.Nm targ 30.Nd SCSI target emulator driver 31.Sh SYNOPSIS 32To compile this driver into the kernel, 33place the following line in your 34kernel configuration file: 35.Bd -ragged -offset indent 36.Cd "device targ" 37.Ed 38.Sh DESCRIPTION 39The 40.Nm 41driver provides an interface for usermode programs to emulate SCSI target 42devices. 43A sample program that emulates a disk drive (similar to 44.Xr da 4 ) 45can be found in 46.Pa /usr/share/examples/scsi_target . 47.Pp 48The 49.Nm 50driver supplies the control device 51.Pa /dev/targ . 52After opening the device, the file descriptor must be bound to a 53specific bus/target/LUN and enabled to process CCBs using the 54.Dv TARGIOCENABLE 55ioctl. 56The process then uses 57.Xr write 2 58to send CCBs to the SIM and 59.Xr poll 2 60or 61.Xr kqueue 2 62to see if responses are ready. 63Pointers to completed CCBs are returned via 64.Xr read 2 . 65Any data transfers requested by the user CCBs are done via zero-copy IO. 66.Sh IOCTLS 67The following 68.Xr ioctl 2 69calls are defined in the header file 70.In cam/scsi/scsi_targetio.h . 71.Bl -tag -width ".Dv TARGIOCDISABLE" 72.It Dv TARGIOCENABLE 73.Pq Vt "struct ioc_enable_lun" 74Enable target mode on the LUN specified by the following structure: 75.Bd -literal -offset indent 76struct ioc_enable_lun { 77 path_id_t path_id; 78 target_id_t target_id; 79 lun_id_t lun_id; 80 int grp6_len; 81 int grp7_len; 82}; 83.Ed 84.Pp 85The selected path (bus), target, and LUN must not already be in use or 86.Er EADDRINUSE 87is returned. 88If 89.Va grp6_len 90or 91.Va grp7_len 92are non-zero, reception of vendor-specific commands 93is enabled. 94.It Dv TARGIOCDISABLE 95Disable target mode and abort all pending CCBs. 96The CCBs may optionally be read as they complete. 97.Dv TARGIOCENABLE 98can then be called to activate a different LUN. 99Multiple disable calls have no effect. 100The 101.Xr close 2 102system call automatically disables target mode if enabled. 103.It Dv TARGIOCDEBUG 104.Pq Vt int 105Enables 106.Dv CAM_PERIPH 107debugging if the argument is non-zero, otherwise disables 108it. 109.El 110.Sh FILES 111.Bl -tag -width ".Pa /sys/cam/scsi/scsi_target.c" -compact 112.It In cam/scsi/scsi_targetio.h 113describes the usermode interface. 114.It Pa /sys/cam/scsi/scsi_target.c 115is the driver source file. 116.It Pa /dev/targ 117is the control device. 118.El 119.Sh SEE ALSO 120.Pa /usr/share/examples/scsi_target , 121.Xr ahc 4 , 122.Xr isp 4 , 123.Xr scsi 4 124.Rs 125.%T "FreeBSD Target Information" 126.%U http://www.root.org/~nate/freebsd/ 127.Re 128.Sh AUTHORS 129.An -nosplit 130The 131.Nm 132driver first appeared in 133.Fx 3.0 134and was written by 135.An Justin T. Gibbs . 136It was rewritten 137for 138.Fx 5.0 139by 140.An Nate Lawson Aq Mt nate@root.org . 141.Sh BUGS 142Currently, only the 143.Xr ahc 4 144and 145.Xr isp 4 146drivers fully support target mode. 147.Pp 148The 149.Xr ahc 4 150driver does not support tagged queuing in target mode. 151