Linux SCSI SG passthrough device API. The intention is to allow for both
running of Linux apps that want to talk to /dev/sg* nodes, and to facilitate
porting of apps from Linux to FreeBSD. As such, both native and linuxolator
entry points and definitions are provided.
Caveats:
- This does not support the procfs and sysfs nodes that the Linux SG
driver provides. Some Linux apps may rely on these for operation,
others may only use them for informational purposes.
- More ioctls need to be implemented.
- Linux uses a naming scheme of "sg[a-z]" for devices, while FreeBSD uses a
scheme of "sg[0-9]". Devfs aliasis (symlinks) are automatically created
to link the two together. However, tools like camcontrol only see the
native names.
- Some operations were originally designed to return byte counts or other
data directly as the syscall return value. The linuxolator doesn't appear
to support this well, so this driver just punts for these cases.
Now that the driver is in place, others are welcome to add missing
functionality. Thanks to Roman Divacky for pushing this work along.
the kernel by wrapping all targets for fake opt_*.h files in
.if defined(KERNBUILDDIR). Thus, such fake files won't be
created at all if modules are built with the kernel.
Some modules undergo cleanup like removing unused or unneeded
options or .h files, without which they wouldn't build this way
or the other.
Reviewed by: ru
Tested by: no binary changes in modules built alone
Tested on: i386 sparc64 amd64
This code allows a user program to enable target mode on a SIM and
then emulate any number of devices (disks, tape drives, etc.) All
decisions about device behavior (UA, CA, inquiry response) are left
to the usermode program and the kernel driver is merely a conduit
for CCBs. This enables multiple concurrent target emulators, each
using its own backing store and IO model.
Also included is a user program that emulates a disk (RBC) using a
file as a backing store. This provides functionality similar to
md(4) at the CAM layer.
Code has been tested on ahc(4) and should also work on isp(4) (and
other SIMs that gain target mode support). It is a complete rewrite
of /sys/cam/scsi_target* and /usr/share/examples/scsi_target.
Design, comments from: gibbs
Supported by: Cryptography Research
Approved by: re
Make the umass driver depend on this module.
Makes it possible to compile the kernel without SCSI support and load it
when for example a USB floppy is conencted.
