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 33.Sh NAME 34.Nm pass 35.Nd CAM application passthrough driver 36.Sh SYNOPSIS 37.Cd device pass 38.Sh DESCRIPTION 39The 40.Nm 41driver provides a way for userland applications to issue CAM CCBs to the 42kernel. 43.Pp 44Since the 45.Nm 46driver allows direct access to the CAM subsystem, system administrators 47should exercise caution when granting access to this driver. 48If used 49improperly, this driver can allow userland applications to crash a machine 50or cause data loss. 51.Pp 52The 53.Nm 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 64device in the kernel; 65.Nm 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. 74Note that some CCB types are not allowed 75through the passthrough device, and must be sent through the 76.Xr xpt 4 77device instead. 78Some examples of xpt-only CCBs are XPT_SCAN_BUS, 79XPT_DEV_MATCH, XPT_RESET_BUS, XPT_SCAN_LUN, XPT_ENG_INQ, and XPT_ENG_EXEC. 80These CCB types have various attributes that make it illogical or 81impossible to service them through the passthrough interface. 82.It CAMGETPASSTHRU 83This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device 84corresponding to the device in question. 85Although this ioctl is available through the 86.Nm 87driver, it is of limited use, since the caller must already know that 88the device in question is a passthrough device if they are issuing this 89ioctl. 90It is probably more useful to issue this ioctl through the 91.Xr xpt 4 92device. 93.El 94.Sh FILES 95.Bl -tag -width /dev/passn -compact 96.It Pa /dev/pass Ns Ar n 97Character device nodes for the 98.Nm 99driver. 100There should be one of these for each device accessed through the 101CAM subsystem. 102.El 103.Sh DIAGNOSTICS 104None. 105.Sh SEE ALSO 106.Xr cam 3 , 107.Xr cam_cdbparse 3 , 108.Xr xpt 4 , 109.Xr camcontrol 8 110.Sh HISTORY 111The CAM passthrough driver first appeared in 112.Fx 3.0 . 113.Sh AUTHORS 114.An Kenneth Merry Aq ken@FreeBSD.org 115.Sh BUGS 116It might be nice to have a way to asynchronously send CCBs through the 117passthrough driver. 118This would probably require some sort of read/write 119interface or an asynchronous ioctl interface. 120