Интерактивная система просмотра системных руководств (man-ов)
xpt (4)
>> xpt (4) ( FreeBSD man: Специальные файлы /dev/* )
BSD mandoc
NAME
xpt
- CAM transport layer interface
SYNOPSIS
None.
DESCRIPTION
The
driver provides a way for userland applications to issue certain CAM CCBs
to the kernel.
Since the
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.
KERNEL CONFIGURATION
There is no kernel configuration required for the
driver.
It is enabled when
SCSI
support is enabled in the kernel.
There is one instance of the xpt driver
per CAM transport layer instance.
Since there is currently only one CAM
transport layer, there will only be one instance of this driver.
IOCTLS
CAMIOCOMMAND
This ioctl takes certain kinds of CAM CCBs and passes them through to the
CAM transport layer for action.
Only the following CCB types are
supported:
XPT_SCAN_BUS
XPT_RESET_BUS
XPT_SCAN_LUN
XPT_ENG_INQ
XPT_ENG_EXEC
XPT_DEBUG
XPT_DEV_MATCH
XPT_PATH_INQ
The above CCBs are the only ones supported since it makes more sense to
send them through a generic passthrough device rather than a passthrough
device tied to a particular underlying
SCSI
device.
CAMGETPASSTHRU
This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device
corresponding to the device in question.
