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nbdkit_shutdown(3) NBDKIT nbdkit_shutdown(3)

NAME

nbdkit_shutdown, nbdkit_disconnect - request shutdown or client disconnection

SYNOPSIS

 #include <nbdkit-plugin.h>
 void nbdkit_shutdown (void);
 void nbdkit_disconnect (int force);

DESCRIPTION

Plugins and filters can call exit(3) in the configuration phase (before and including ".get_ready", but not in connected callbacks).

Once nbdkit has started serving connections, plugins and filters should not call exit(3). However they may instruct nbdkit to shut down by calling "nbdkit_shutdown", or to disconnect a single client by calling "nbdkit_disconnect".

nbdkit_shutdown

"nbdkit_shutdown" requests nbdkit to shut down asynchronously and returns (note that it does not exit the process immediately).

It ensures that the plugin and all filters are unloaded cleanly which may take some time. Further callbacks from nbdkit into the plugin or filter may occur after you have called this.

nbdkit_disconnect

"nbdkit_disconnect" requests that the current client connection be disconnected. It does not affect other connections, and it does not stop the same client from trying to reconnect.

It is only useful from connected callbacks — that is, after (but not including) ".open", and before ".close". To reject a client in ".preconnect", ".open" or ".list_exports" you should return an error instead.

If "force" is true, nbdkit will disconnect the client immediately, and the client will not receive any response to the current command or any other commands in flight in parallel threads. If "force" is false, nbdkit will not accept any new commands from the client (failing all commands other than "NBD_CMD_DISC" with "ESHUTDOWN"), but will allow existing commands to complete gracefully. Either way, the next callback for the current connection should be ".close".

LANGUAGE BINDINGS

In nbdkit-ocaml-plugin(3):

 NBDKit.shutdown : unit -> unit
 NBDKit.disconnect : bool -> unit

In nbdkit-python-plugin(3):

 import nbdkit
 nbdkit.shutdown()
 nbdkit.disconnect(force)

In nbdkit-rust-plugin(3):

 use nbdkit::*;
 pub fn shutdown()
 pub fn disconnect(force: bool)

In nbdkit-sh-plugin(3), there are various magic error codes that can be returned to indicate that shutdown or disconnection is needed. See that documentation for a full description.

HISTORY

"nbdkit_shutdown" was added in nbdkit 1.20. "nbdkit_disconnect" was added in nbdkit 1.34.

SEE ALSO

nbdkit(1), nbdkit-plugin(3), nbdkit-filter(3).

AUTHORS

Eric Blake

Richard W.M. Jones

COPYRIGHT

Copyright Red Hat

LICENSE

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

2024-10-30 nbdkit-1.40.4