1.\" 2.\" Copyright (c) 1998, 1999 Kenneth D. Merry. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.\" 30.Dd October 10, 1998 31.Dt PASS 4 32.Os FreeBSD 3.0 33.Sh NAME 34.Nm pass 35.Nd CAM application passthrough driver 36.Sh SYNOPSIS 37.Cd device pass0 38.Cd device pass2 at scbus0 target 3 unit 0 39.Sh DESCRIPTION 40The 41.Nm pass 42driver provides a way for userland applications to issue CAM CCBs to the 43kernel. 44.Pp 45Since the 46.Nm pass 47driver allows direct access to the CAM subsystem, system administrators 48should exercise caution when granting access to this driver. If used 49improperly, this driver can allow userland applications to crash a machine 50or cause data loss. 51.Pp 52The 53.Nm pass 54driver attaches to every 55.Tn SCSI 56device found in the system. 57Since it attaches to every device, it provides a generic means of accessing 58.Tn SCSI 59devices, and allows the user to access devices which have no 60"standard" peripheral driver associated with them. 61.Sh KERNEL CONFIGURATION 62It is only necessary to configure one 63.Nm pass 64device in the kernel; 65.Nm pass 66devices are automatically allocated as 67.Tn SCSI 68devices are found. 69.Sh IOCTLS 70.Bl -tag -width 012345678901234 71.It CAMIOCOMMAND 72This ioctl takes most kinds of CAM CCBs and passes them through to the CAM 73transport layer for action. Note that some CCB types are not allowed 74through the passthrough device, and must be sent through the 75.Xr xpt 4 76device instead. Some examples of xpt-only CCBs are XPT_SCAN_BUS, 77XPT_DEV_MATCH, XPT_RESET_BUS, XPT_SCAN_LUN, XPT_ENG_INQ, and XPT_ENG_EXEC. 78These CCB types have various attributes that make it illogical or 79impossible to service them through the passthrough interface. 80.It CAMGETPASSTHRU 81This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device 82corresponding to the device in question. Although this ioctl is available 83through the 84.Nm pass 85driver, it is of limited use, since the caller must already know that 86the device in question is a passthrough device if they're issuing this 87ioctl. It is probably more useful to issue this ioctl through the 88.Xr xpt 4 89device. 90.El 91.Sh FILES 92.Bl -tag -width 01234567890 -compact 93.It Pa /dev/pass Ns Ar n 94Character device nodes for the 95.Nm pass 96driver. There should be one of these for each device accessed through the 97CAM subsystem. 98.El 99.Sh DIAGNOSTICS 100None. 101.Sh SEE ALSO 102.Xr cam 3 , 103.Xr cam_cdbparse 3 , 104.Xr xpt 4 , 105.Xr camcontrol 8 106.Sh HISTORY 107The CAM passthrough driver first appeared in 108.Fx 3.0 . 109.Sh AUTHORS 110.An Kenneth Merry Aq ken@FreeBSD.ORG 111.Sh BUGS 112It might be nice to have a way to asynchronously send CCBs through the 113passthrough driver. This would probably require some sort of read/write 114interface or an asynchronous ioctl interface. 115