This is the libnvme development C library. libnvme provides type definitions for NVMe specification structures, enumerations, and bit fields, helper functions to construct, dispatch, and decode commands and payloads, and utilities to connect, scan, and manage nvme devices on a Linux system.
The public specification is the authority to resolve any protocol discrepancies with this library. For more info on NVM Express, please see:
Subscribe to linux-nvme@lists.infradead.org for linux-nvme related discussions and development for both kernel and userspace. The list is archived here:
https://lists.infradead.org/mailman/listinfo/linux-nvme
Except where otherwise stated, all software contained within this repo is currently licensed LGPL-2.1-or-later, see COPYING for more information.
Keith Busch 2020-02-06
libnvme depends on minimum Linux kernel version v4.15, which introduced the /sys/class/nvme-subsystem.
A minimal build depends on a set of build tools
- gcc
- ninja
- meson
Not all feature will be present with such configuration, e.g. the fabrics part of the library wont support authentication or TLS over the nvme-tcp transport.
To enable the optional features install following libraries
`/etc/nvme/config.json`` support:
- json-c (recommend)
Authentication and TLS over nvme-tcp:
- openssl
- keyutils
End point discovery for MI
- libdbus
Python bindings
- Python 3 interpreter
- Python 3 development libraries
The reference implemention of the Meson specification is in Python 3. Installing or porting this dependency is not really feasible for embedded project. Though there are two project which implement the Ninja and the Meson API in pure C99
The CI build helper script scripts/build.sh is able to setup and build this
project in a minimal setup using samurai and muon and thus only depending on:
- gcc
- make
- git
scripts/build.sh -m muon
To configure the project:
meson setup .build
Which will default to build a shared library. To configure for static libraries call
meson setup --default-library=static .build
One nice feature of meson is that it doesn't mix build artifacts
(e.g. *.o, *.so, etc.) with source code. In the above example,
".build" is the name of the directory where the build configuration
as well as all the build artifacts will be saved. This directory can
be named anything as long as it's not an existing source directory. To
completely "clean" all the build artifacts, one need only delete the
.build directory.
To compile:
meson compile -C .build
To install libnvme:
meson install -C .build
To run unit tests:
meson test -C .build
To completely clean all build artifacts, including the build configuration.
rm -rf .build
A few build options can be specified on the command line when invoking meson.
| Option | Values [default] | Description |
|---|---|---|
| version-tag | none | Overwrite the git version string in the binary |
| htmldir | none | Installation directory for the HTML documentation |
| rstdir | none | Installation directory for the RST documentation |
| docs | [false], html, man, rst, all | Install documentation |
| docs-build | [false], true | Enable build documentation |
| python | [auto], enabled, disabled | Whether to build the Python bindings. When set to auto, the default, meson will check for the presence of the tools and libraries (e.g. swig) required to build the Python bindings. If found, meson will configure the project to build the Python bindings. If a tool or library is missing, then the Python bindings won't be built. Setting this to enabled, forces the Python bindings to be built. When set to disabled, meson will configure the project to not build the Python bindings.Example: meson setup .build -Dpython=disabled |
| openssl | [auto], enabled, disabled | Enables OpenSSL dependent features (e.g. TLS over TCP), adds build dependency on OpenSSL |
| libdbus | auto, enabled, [disabled] | Enables D-Bus dependent features (libnvme-mi: End point discovery), adds build dependency on libdbus |
| json-c | [auto], enabled, disabled | (recommended) Enables JSON-C dependend features (e.g. config.json parsing), adds build depdency on json-c |
| keyutils | [auto], enabled, disabled | Enables keyutils dependent features (e.g. authentication), adds build dependency on keyutils |
| liburing | [auto], enabled, disabled | Enables liburing dependent features (e.g. get log page by uring cmd), adds build depdency on liburing |
See the full configuration options with
meson configure .buildTo configure a build for debugging purposes (i.e. optimization turned off and debug symbols enabled):
meson setup .build --buildtype=debugTo enable address sanitizer (advanced debugging of memory issues):
meson setup .build -Db_sanitize=addressThis option adds -fsanitize=address to the gcc options. The tests can then be run normally (meson test -C .build).
Note that when using the sanitize feature, the library libasan.so must be available and must be the very first library loaded when running an executable. If experiencing linking issues, you can ensure that libasan.so gets loaded first with the LD_PRELOAD environment variable as follows:
meson setup .build -Db_sanitize=address && LD_PRELOAD=/lib64/libasan.so.6 ninja -C .build test
It's also possible to enable the undefined behavior sanitizer with -Db_sanitize=undefined. To enable both, use -Db_sanitize=address,undefined.