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diff --git a/static/freebsd/man4/pass.4 b/static/freebsd/man4/pass.4 new file mode 100644 index 00000000..0a5a58c2 --- /dev/null +++ b/static/freebsd/man4/pass.4 @@ -0,0 +1,240 @@ +.\" +.\" Copyright (c) 1998, 1999 Kenneth D. Merry. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.Dd May 3, 2017 +.Dt PASS 4 +.Os +.Sh NAME +.Nm pass +.Nd CAM application passthrough driver +.Sh SYNOPSIS +.Cd device pass +.Sh DESCRIPTION +The +.Nm +driver provides a way for userland applications to issue CAM CCBs to the +kernel. +.Pp +Since the +.Nm +driver allows direct access to the CAM subsystem, system administrators +should exercise caution when granting access to this driver. +If used +improperly, this driver can allow userland applications to crash a machine +or cause data loss. +.Pp +The +.Nm +driver attaches to every +.Tn SCSI +and +.Tn ATA +device found in the system. +Since it attaches to every device, it provides a generic means of accessing +.Tn SCSI +and +.Tn ATA +devices, and allows the user to access devices which have no +"standard" peripheral driver associated with them. +.Sh KERNEL CONFIGURATION +It is only necessary to configure one +.Nm +device in the kernel; +.Nm +devices are automatically allocated as +.Tn SCSI +and +.Tn ATA +devices are found. +.Sh IOCTLS +.Bl -tag -width 5n +.It CAMIOCOMMAND union ccb * +This ioctl takes most kinds of CAM CCBs and passes them through to the CAM +transport layer for action. +Note that some CCB types are not allowed +through the passthrough device, and must be sent through the +.Xr xpt 4 +device instead. +Some examples of xpt-only CCBs are XPT_SCAN_BUS, +XPT_DEV_MATCH, XPT_RESET_BUS, XPT_SCAN_LUN, XPT_ENG_INQ, and XPT_ENG_EXEC. +These CCB types have various attributes that make it illogical or +impossible to service them through the passthrough interface. +.Pp +If the user would like the kernel to do error recovery, the +.Dv CAM_PASS_ERR_RECOVER +flag must be set on the CCB, and the retry_count field set to the number +of retries. +.It CAMGETPASSTHRU union ccb * +This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device +corresponding to the device in question. +Although this ioctl is available through the +.Nm +driver, it is of limited use, since the caller must already know that +the device in question is a passthrough device if they are issuing this +ioctl. +It is probably more useful to issue this ioctl through the +.Xr xpt 4 +device. +.It CAMIOQUEUE union ccb * +Queue a CCB to the +.Nm +driver to be executed asynchronously. +The caller may use +.Xr select 2 , +.Xr poll 2 +or +.Xr kevent 2 +to receive notification when the CCB has completed. +.Pp +This ioctl takes most CAM CCBs, but some CCB types are not allowed through +the pass device, and must be sent through the +.Xr xpt 4 +device instead. +Some examples of xpt-only CCBs are XPT_SCAN_BUS, +XPT_DEV_MATCH, XPT_RESET_BUS, XPT_SCAN_LUN, XPT_ENG_INQ, and XPT_ENG_EXEC. +These CCB types have various attributes that make it illogical or +impossible to service them through the passthrough interface. +.Pp +Although the +.Dv CAMIOQUEUE +ioctl is not defined to take an argument, it does require a +pointer to a union ccb. +It is not defined to take an argument to avoid an extra malloc and copy +inside the generic +.Xr ioctl 2 +handler. +.Pp +The completed CCB will be returned via the +.Dv CAMIOGET +ioctl. +An error will only be returned from the +.Dv CAMIOQUEUE +ioctl if there is an error allocating memory for the request or copying +memory from userland. +All other errors will be reported as standard CAM CCB status errors. +Since the CCB is not copied back to the user process from the pass driver +in the +.Dv CAMIOQUEUE +ioctl, the user's passed-in CCB will not be modified. +This is the case even with immediate CCBs. +Instead, the completed CCB must be retrieved via the +.Dv CAMIOGET +ioctl and the status examined. +.Pp +Multiple CCBs may be queued via the +.Dv CAMIOQUEUE +ioctl at any given time, and they may complete in a different order than +the order that they were submitted. +The caller must take steps to identify CCBs that are queued and completed. +The +.Dv periph_priv +structure inside struct ccb_hdr is available for userland use with the +.Dv CAMIOQUEUE +and +.Dv CAMIOGET +ioctls, and will be preserved across calls. +Also, the periph_links linked list pointers inside struct ccb_hdr are +available for userland use with the +.Dv CAMIOQUEUE +and +.Dv CAMIOGET +ioctls and will be preserved across calls. +.Pp +If the user would like the kernel to do error recovery, the +.Dv CAM_PASS_ERR_RECOVER +flag must be set on the CCB, and the retry_count field set to the number +of retries. +.It CAMIOGET union ccb * +Retrieve completed CAM CCBs queued via the +.Dv CAMIOQUEUE +ioctl. +An error will only be returned from the +.Dv CAMIOGET +ioctl if the +.Nm +driver fails to copy data to the user process or if there are no completed +CCBs available to retrieve. +If no CCBs are available to retrieve, +errno will be set to +.Dv ENOENT . +.Pp +All other errors will be reported as standard CAM CCB status errors. +.Pp +Although the +.Dv CAMIOGET +ioctl is not defined to take an argument, it does require a +pointer to a union ccb. +It is not defined to take an argument to avoid an extra malloc and copy +inside the generic +.Xr ioctl 2 +handler. +.Pp +The pass driver will report via +.Xr select 2 , +.Xr poll 2 +or +.Xr kevent 2 +when a CCB has completed. +One CCB may be retrieved per +.Dv CAMIOGET +call. +CCBs may be returned in an order different than the order they were +submitted. +So the caller should use the +.Dv periph_priv +area inside the CCB header to store pointers to identifying information. +.El +.Sh FILES +.Bl -tag -width /dev/passn -compact +.It Pa /dev/pass Ns Ar n +Character device nodes for the +.Nm +driver. +There should be one of these for each device accessed through the +CAM subsystem. +.El +.Sh DIAGNOSTICS +None. +.Sh SEE ALSO +.Xr kqueue 2 , +.Xr poll 2 , +.Xr select 2 , +.Xr cam 3 , +.Xr cam_cdbparse 3 , +.Xr cam 4 , +.Xr cd 4 , +.Xr ctl 4 , +.Xr da 4 , +.Xr sa 4 , +.Xr xpt 4 , +.Xr camcontrol 8 , +.Xr camdd 8 +.Sh HISTORY +The CAM passthrough driver first appeared in +.Fx 3.0 . +.Sh AUTHORS +.An Kenneth Merry Aq Mt ken@FreeBSD.org |