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 34.Cd device targ 35.Sh DESCRIPTION 36The 37.Nm 38driver provides an interface for usermode programs to emulate SCSI target 39devices. A sample program that emulates a disk drive (similar to 40.Xr da 4 ) 41can be found in /usr/share/examples/scsi_target. 42.Pp 43The 44.Nm 45driver supplies control devices, 46.Pa /dev/targ0 , 47.Pa /dev/targ1 , 48etc. 49If a device is already in use, the open will fail and 50.Va errno 51will be set to 52.Er EBUSY . 53After opening the device, the file descriptor must be bound to a 54specific bus/target/lun and enabled to process CCBs using the 55.Pa TARGIOCENABLE 56ioctl. 57The process then uses 58.Xr write 2 59to send CCBs to the SIM and 60.Xr poll 2 61or 62.Xr kqueue 2 63to see if responses are ready. Pointers 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.Pp 67.Sh IOCTLS 68The following 69.Xr ioctl 2 70calls are defined in the header file 71.Aq Pa cam/scsi/scsi_targetio.h . 72.Bl -tag -width TARGIOCDISABLE 73.It Dv TARGIOCENABLE 74.Pq Li "struct ioc_enable_lun" 75Enable target mode on the LUN specified by the following structure: 76.Bd -literal -offset indent 77struct ioc_enable_lun { 78 path_id_t path_id; 79 target_id_t target_id; 80 lun_id_t lun_id; 81 int grp6_len; 82 int grp7_len; 83}; 84.Ed 85.Pp 86The selected path (bus), target, and lun must not already be in use or 87.Er EADDRINUSE 88is returned. 89If grp6_len or grp7_len are non-zero, reception of vendor-specific commands 90is enabled. 91.It Dv TARGIOCDISABLE 92Disable target mode and abort all pending CCBs. 93The CCBs may optionally be read as they complete. 94.Pa TARGIOCENABLE 95can then be called to activate a different LUN. 96Multiple disable calls have no effect. 97The 98.Xr close 2 99system call automatically disables target mode if enabled. 100.It Dv TARGIOCDEBUG 101.Pq Li "int" 102Enables CAM_PERIPH debugging if the argument is non-zero, otherwise disables 103it. 104.El 105.Sh FILES 106.Bl -tag -width /sys/cam/scsi/scsi_target.c -compact 107.It Aq Pa cam/scsi/scsi_targetio.h 108describes the usermode interface. 109.It Pa /sys/cam/scsi/scsi_target.c 110is the driver source file. 111.It Pa /dev/targ* 112are the control devices. 113.El 114.Sh SEE ALSO 115.Xr /usr/share/examples/scsi_target , 116.Xr scsi 4 117.Rs 118.%T "FreeBSD Target Information" 119.%O http://www.root.org/~nate/freebsd/ 120.Re 121.Sh BUGS 122Currently, only the 123.Xr ahc 4 124driver fully supports target mode. The 125.Xr isp 4 126and 127.Xr sym 4 128drivers have some target mode support but are untested. 129.Pp 130The 131.Xr ahc 4 132driver does not support tagged queuing in target mode. 133.Sh AUTHORS 134The 135.Nm 136driver first appeared in 137.Fx 3.0 and was written by 138.An Justin T. Gibbs . 139It was rewritten 140for 141.Fx 5.0 142by 143.An Nate Lawson Aq nate@root.org . 144