.TH SCSI_ID 8 "December 2003" "" "Linux Administrator's Manual"
.SH NAME
scsi_id \- retrieve and generate a unique SCSI identifier
.SH SYNOPSIS
.BI scsi_id 
[\fIoptions\fP]
.SH "DESCRIPTION"
.B scsi_id
queries a SCSI device via the SCSI INQUIRY vital product data (VPD) page 0x80 or
0x83 and uses the resulting data to generate a value that is unique across
all SCSI devices that properly support page 0x80 or page 0x83. 

If a result is generated it is sent to standard output, and the program
exits with a zero value. If no identifier is output, the program exits
with a non\-zero value.

\fBscsi_id\fP is primarily for use by other utilities such as \fBudev\fP
that require a unique SCSI identifier.

By default all devices are assume black listed, the \fB\-g\fP option must
be specified on the command line or in the config file for any useful
behaviour.

SCSI commands are sent directly to the device via the SG_IO ioctl
interface.

In order to generate unique values for either page 0x80 or page 0x83, the
serial numbers or world wide names are prefixed as follows.

Identifiers based on page 0x80 are prefixed by the character 'S', the SCSI
vendor, the SCSI product (model) and then the the serial number returned
by page 0x80. For example:

.sp
.nf
# scsi_id -p 0x80 -s /block/sdg
SIBM     3542           1T05078453
.fi
.P

Identifiers based on page 0x83 are prefixed by the identifier type
followed by the page 0x83 identifier. For example, a device with a NAA
(Name Address Authority) type of 3 (also in this case the page 0x83
identifier starts with the NAA value of 6):

.sp
.nf
# /sbin/scsi_id -p 0x83 -s /block/sdg
3600a0b80000b174b000000d63efc5c8c
.fi
.P

.SH OPTIONS
.TP
.BI subsystem
When called with only a single argument without a leading \-, runs in a hotplug
mode, and expects the environment variable DEVPATH to specify the
corresponding sysfs device. See section below on usage with \fBudev\fP.
.TP
.BI \-b
The default behaviour \- treat the device as black listed, and do nothing
unless a white listed device is found in the scsi_id config\-file.
.TP
.BI \-d "\| device\^"
Instead
of determining and creating a device node based on a sysfs dev
entry as done for the \fB\-s\fP, send SG_IO commands to 
\fBdevice\fP, such as \fB/dev/sdc\fP.
.TP
.BI \-f "\| config\-file"
Read configuration and black/white list entries from
.B config\-file 
rather than the default
.B /etc/scsi_id.config
file.
.TP
.BI \-g
Treat the device as white listed. The \fB\-g\fP option must be specified
on the command line or in the scsi_id configuration file for 
.B scsi_id
to generate any output.
.TP
.BI \-i
Prefix the identification string with the  driver model (sysfs) bus id of
the SCSI device.
.TP
.BI \-p "\| 0x80 | 0x83"
Use SCSI INQUIRY VPD page code 0x80 or 0x83. The default behaviour is to
query the available VPD pages, and use page 0x83 if found, else page 0x80
if found, else nothing.
.TP
.BI \-s "\| sysfs\-device"
Generate an id for the
.B sysfs\-device.
The sysfs mount point must not be included. For example, use /block/sd,
not /sys/block/sd.
.TP
.BI \-u
Reformat the output : replace all whitespaces by underscores
.TP
.BI \-v
Generate verbose debugging output.
.TP
.BI \-V
Display version number and exit.
.RE

.SH USAGE WITH UDEV 
If \fBscsi_id\fP is invoked with one argument without a leading \-, it
assumes it is called for a hotplug event, and looks for the sysfs device
in the DEVPATH environment variable. 

This mode is used when run via the \fBudev\fP PROGRAM key. Passing any
arguments or options as part of the PROGRAM rule breaks this assumption,
and the results will likely not be as expected.

When in this mode, all errors and warnings are sent via syslog.

To determine the specific value needed in a RESULT key, use the \-s option,
for example:

.sp
.nf
/sbin/scsi_id -s /block/sda
.fi
.P

An example \fBudev\fP rule using \fBscsi_id\fP, that will name a block
device and any partitions for the device matching the \fBscsi_id\fP output
of 312345:

.sp
.nf
BUS="scsi", PROGRAM="/sbin/scsi_id", RESULT="312345", NAME="disk%n"
.fi
.P

.SH "FILES"
.nf
.ft B
.ft
/etc/scsi_id.config                  configuration and black/white list entries
.fi
.LP
.SH "SEE ALSO"
.BR udev (8), hotplug (8)
.SH AUTHORS
Developed by Patrick Mansfield <patmans@us.ibm.com> based on SCSI ID
source included in earlier linux 2.5 kernels, sg_utils source, and SCSI
specifications.