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. If used 48improperly, this driver can allow userland applications to crash a machine 49or cause data loss. 50.Pp 51The 52.Nm 53driver attaches to every 54.Tn SCSI 55device found in the system. 56Since it attaches to every device, it provides a generic means of accessing 57.Tn SCSI 58devices, and allows the user to access devices which have no 59"standard" peripheral driver associated with them. 60.Sh KERNEL CONFIGURATION 61It is only necessary to configure one 62.Nm 63device in the kernel; 64.Nm 65devices are automatically allocated as 66.Tn SCSI 67devices are found. 68.Sh IOCTLS 69.Bl -tag -width 012345678901234 70.It CAMIOCOMMAND 71This ioctl takes most kinds of CAM CCBs and passes them through to the CAM 72transport layer for action. Note that some CCB types are not allowed 73through the passthrough device, and must be sent through the 74.Xr xpt 4 75device instead. Some examples of xpt-only CCBs are XPT_SCAN_BUS, 76XPT_DEV_MATCH, XPT_RESET_BUS, XPT_SCAN_LUN, XPT_ENG_INQ, and XPT_ENG_EXEC. 77These CCB types have various attributes that make it illogical or 78impossible to service them through the passthrough interface. 79.It CAMGETPASSTHRU 80This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device 81corresponding to the device in question. Although this ioctl is available 82through the 83.Nm 84driver, it is of limited use, since the caller must already know that 85the device in question is a passthrough device if they're issuing this 86ioctl. It is probably more useful to issue this ioctl through the 87.Xr xpt 4 88device. 89.El 90.Sh FILES 91.Bl -tag -width /dev/passn -compact 92.It Pa /dev/pass Ns Ar n 93Character device nodes for the 94.Nm 95driver. There should be one of these for each device accessed through the 96CAM subsystem. 97.El 98.Sh DIAGNOSTICS 99None. 100.Sh SEE ALSO 101.Xr cam 3 , 102.Xr cam_cdbparse 3 , 103.Xr xpt 4 , 104.Xr camcontrol 8 105.Sh HISTORY 106The CAM passthrough driver first appeared in 107.Fx 3.0 . 108.Sh AUTHORS 109.An Kenneth Merry Aq ken@FreeBSD.org 110.Sh BUGS 111It might be nice to have a way to asynchronously send CCBs through the 112passthrough driver. This would probably require some sort of read/write 113interface or an asynchronous ioctl interface. 114