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README_nvme_cli.md

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nvme-cli

NVM-Express user space tooling for Linux.

To install, run:

make && make install

If not sure how to use, find the top-level documentation with:

man nvme

Or find a short summary with:

nvme help

Distro Support

Fedora

nvme-cli is available in Fedora 23 and up. Install it with your favorite package manager. For example:

$ sudo dnf install nvme-cli

Ubuntu

nvme-cli is supported in the Universe package sources for Xenial for many architectures. For a complete list try running:

rmadison nvme-cli
 nvme-cli | 0.3-1 | xenial/universe | source, amd64, arm64, armhf, i386, powerpc, ppc64el, s390x

A Debian based package for nvme-cli is currently maintained as a Ubuntu PPA. Right now there is support for Trusty, Vivid and Wiley. To install nvme-cli using this approach please perform the following steps:

  1. Add the sbates PPA to your sources. One way to do this is to run
sudo add-apt-repository ppa:sbates
  1. Perform an update of your repository list:
sudo apt-get update
  1. Get nvme-cli!
sudo apt-get install nvme-cli
  1. Test the code.
sudo nvme list

In the case of no NVMe devices you will see

No NVMe devices detected.

otherwise you will see information about each NVMe device installed in the system.

Alpine Linux

nvme-cli is tested on Alpine Linux 3.3. Install it using:

# akp update && apk add nvme-cli nvme-cli-doc

if you just use the device you're after, it will work flawless.

# nvme smart-log /dev/nvme0
Smart Log for NVME device:/dev/nvme0 namespace-id:ffffffff
critical_warning                    : 0
temperature                         : 49 C
available_spare                     : 100%

openSUSE Tumbleweed

nvme-cli is available in openSUSE Tumbleweed. You can install it using zypper. For example:

$ sudo zypper install nvme-cli

Arch Linux

Install from AUR, e.g.:

$ yaourt -S nvme-cli-git

Nix(OS)

The attribute is named nvme-cli and can e.g. be installed with:

$ nix-env -f '<nixpkgs>' -iA nvme-cli

Other Distros

TBD

Developers

You may wish to add a new command or possibly an entirely new plug-in for some special extension outside the spec.

This project provides macros that help generate the code for you. If you're interested in how that works, it is very similar to how trace events are created by Linux kernel's 'ftrace' component.

Add command to existing built-in

The first thing to do is define a new command entry in the command list. This is declared in nvme-builtin.h. Simply append a new "ENTRY" into the list. The ENTRY normally takes three arguments: the "name" of the subcommand (this is what the user will type at the command line to invoke your command), a short help description of what your command does, and the name of the function callback that you're going to write. Additionally, You can declare an alias name of subcommand with fourth argument, if needed.

After the ENTRY is defined, you need to implement the callback. It takes four arguments: argc, argv, the command structure associated with the callback, and the plug-in structure that contains that command. The prototype looks like this:

int f(int argc, char **argv, struct command *cmd, struct plugin *plugin);

The argc and argv are adjusted from the command line arguments to start after the sub-command. So if the command line is "nvme foo --option=bar", the argc is 1 and argv starts at "--option".

You can then define argument parsing for your sub-command's specific options then do some command specific action in your callback.

Add a new plugin

The nvme-cli provides macros to make define a new plug-in simpler. You can certainly do all this by hand if you want, but it should be easier to get going using the macros. To start, first create a header file to define your plugin. This is where you will give your plugin a name, description, and define all the sub-commands your plugin implements.

There is a very important order on how to define the plugin. The following is a basic example on how to start this:

File: foo-plugin.h

#undef CMD_INC_FILE
#define CMD_INC_FILE foo-plugin

#if !defined(FOO) || defined(CMD_HEADER_MULTI_READ)
#define FOO

#include "cmd.h"

PLUGIN(NAME("foo", "Foo plugin"),
	COMMAND_LIST(
		ENTRY("bar", "foo bar", bar)
		ENTRY("baz", "foo baz", baz)
		ENTRY("qux", "foo quz", qux)
	)
);

#endif

#include "define_cmd.h"

In order to have the compiler generate the plugin through the xmacro expansion, you need to include this header in your source file, with pre-defining macro directive to create the commands.

To get started from the above example, we just need to define "CREATE_CMD" and include the header:

File: foo-plugin.c

#define CREATE_CMD
#include "foo-plugin.h"

After that, you just need to implement the functions you defined in each ENTRY, then append the object file name to the Makefile's "OBJS".