nvme-cli/Documentation/nvme-id-ctrl.1

'\" t
.\"     Title: nvme-id-ctrl
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 10/31/2024
.\"    Manual: NVMe Manual
.\"    Source: NVMe
.\"  Language: English
.\"
.TH "NVME\-ID\-CTRL" "1" "10/31/2024" "NVMe" "NVMe Manual"
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.nh
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.SH "NAME"
nvme-id-ctrl \- Send NVMe Identify Controller, return result and structure
.SH "SYNOPSIS"
.sp
.nf
\fInvme id\-ctrl\fR <device> [\-\-vendor\-specific | \-V] [\-\-raw\-binary | \-b]
                        [\-\-output\-format=<fmt> | \-o <fmt>] [\-\-verbose | \-v]
.fi
.SH "DESCRIPTION"
.sp
For the NVMe device given, sends an identify controller command and provides the result and returned structure\&.
.sp
The <device> parameter is mandatory and may be either the NVMe character device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1)\&.
.sp
On success, the structure may be returned in one of several ways depending on the option flags; the structure may be parsed by the program or the raw buffer may be printed to stdout\&.
.SH "OPTIONS"
.PP
\-b, \-\-raw\-binary
.RS 4
Print the raw buffer to stdout\&. Structure is not parsed by program\&. This overrides the vendor specific and human readable options\&.
.RE
.PP
\-V, \-\-vendor\-specific
.RS 4
In addition to parsing known fields, this option will dump the vendor specific region of the structure in hex with ascii interpretation\&.
.RE
.PP
\-H, \-\-human\-readable
.RS 4
This option will parse and format many of the bit fields into human\-readable formats\&.
.RE
.PP
\-o <fmt>, \-\-output\-format=<fmt>
.RS 4
Set the reporting format to
\fInormal\fR,
\fIjson\fR
or
\fIbinary\fR\&. Only one output format can be used at a time\&.
.RE
.PP
\-v, \-\-verbose
.RS 4
Increase the information detail in the output\&.
.RE
.SH "EXAMPLES"
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Has the program interpret the returned buffer and display the known fields in a human readable format:
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme id\-ctrl /dev/nvme0
.fi
.if n \{\
.RE
.\}
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
In addition to showing the known fields, has the program to display the vendor unique field:
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme id\-ctrl /dev/nvme0 \-\-vendor\-specific
# nvme id\-ctrl /dev/nvme0 \-V
.fi
.if n \{\
.RE
.\}
.sp
The above will dump the
\fIvs\fR
buffer in hex since it doesn\(cqt know how to interpret it\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Have the program return the raw structure in binary:
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme id\-ctrl /dev/nvme0 \-\-raw\-binary > id_ctrl\&.raw
# nvme id\-ctrl /dev/nvme0 \-b > id_ctrl\&.raw
.fi
.if n \{\
.RE
.\}
.sp
It is probably a bad idea to not redirect stdout when using this mode\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Alternatively you may want to send the data to another program that can parse the raw buffer\&.
.sp
.if n \{\
.RS 4
.\}
.nf
# nvme id\-ctrl /dev/nvme0 \-\-raw\-binary | nvme_parse_id_ctrl
.fi
.if n \{\
.RE
.\}
.sp
The parse program in the above example can be a program that shows the structure in a way you like\&. The following program is such an example that will parse it and can accept the output through a pipe,
\*(Aq|\*(Aq, as shown in the above example, or you can
\*(Aqcat\*(Aq
a saved output buffer to it\&.
.RE
.sp
.if n \{\
.RS 4
.\}
.nf
/* File: nvme_parse_id_ctrl\&.c */

#include <linux/nvme\&.h>
#include <stdio\&.h>
#include <unistd\&.h>

int main(int argc, char **argv)
{
        unsigned char buf[sizeof(struct nvme_id_ctrl)];
        struct nvme_id_ctrl *ctrl = (struct nvme_id_ctrl *)buf;

        if (read(STDIN_FILENO, buf, sizeof(buf)))
                return 1;

        printf("vid   : %#x\en", ctrl\->vid);
        printf("ssvid : %#x\en", ctrl\->ssvid);
        return 0;
}
.fi
.if n \{\
.RE
.\}
.SH "NVME"
.sp
Part of the nvme\-user suite