NBDKit - Man Page

Module   NBDKit

Module NBDKit
: sig end

Interface between plugins written in OCaml and the nbdkit server.

Read nbdkit-ocaml-plugin(3) first.

type flags = flag list

Flags passed from the server to various callbacks.

type flag =
| May_trim
| FUA
| Req_one

type fua_flag =
| FuaNone
| FuaEmulate
| FuaNative

type cache_flag =
| CacheNone
| CacheEmulate
| CacheNop

type extent = {
offset : int64 ;
length : int64 ;
is_hole : bool ;
is_zero : bool ;
}

The type of the extent list returned by extents

type export = {
name : string ;
description : string option ;
}

The type of the export list returned by list_exports

type thread_model =
| THREAD_MODEL_SERIALIZE_CONNECTIONS
| THREAD_MODEL_SERIALIZE_ALL_REQUESTS
| THREAD_MODEL_SERIALIZE_REQUESTS
| THREAD_MODEL_PARALLEL

The type of the thread model returned by thread_model

val register_plugin : name:string -> ?longname:string -> ?version:string -> ?description:string -> ?load:(unit -> unit) -> ?get_ready:(unit -> unit) -> ?after_fork:(unit -> unit) -> ?cleanup:(unit -> unit) -> ?unload:(unit -> unit) -> ?config:(string -> string -> unit) -> ?config_complete:(unit -> unit) -> ?config_help:string -> ?thread_model:(unit -> thread_model) -> ?magic_config_key:string -> ?preconnect:(bool -> unit) -> open_connection:(bool -> 'a) -> ?close:('a -> unit) -> get_size:('a -> int64) -> ?can_cache:('a -> cache_flag) -> ?can_extents:('a -> bool) -> ?can_fast_zero:('a -> bool) -> ?can_flush:('a -> bool) -> ?can_fua:('a -> fua_flag) -> ?can_multi_conn:('a -> bool) -> ?can_trim:('a -> bool) -> ?can_write:('a -> bool) -> ?can_zero:('a -> bool) -> ?is_rotational:('a -> bool) -> pread:('a -> int32 -> int64 -> flags -> string) -> ?pwrite:('a -> string -> int64 -> flags -> unit) -> ?flush:('a -> flags -> unit) -> ?trim:('a -> int32 -> int64 -> flags -> unit) -> ?zero:('a -> int32 -> int64 -> flags -> unit) -> ?extents:('a -> int32 -> int64 -> flags -> extent list) -> ?cache:('a -> int32 -> int64 -> flags -> unit) -> ?dump_plugin:(unit -> unit) -> ?list_exports:(bool -> bool -> export list) -> ?default_export:(bool -> bool -> string) -> ?export_description:('a -> string) -> unit -> unit

Register the plugin with nbdkit.

The 'a parameter is the handle type returned by your open_connection method and passed back to all connected calls.

val set_error : Unix.error -> unit

Set the errno returned over the NBD protocol to the client.

Notice however that the NBD protocol only supports a small handful of errno values.  Any other errno will be translated into EINVAL .

val parse_size : string -> int64

Bindings for nbdkit_parse_size , nbdkit_parse_bool and nbdkit_read_password .  See nbdkit-plugin(3) for information about these functions.

On error these functions all raise Invalid_argument .  The actual error is sent to the nbdkit error log and is not available from the OCaml code.  It is usually best to let the exception escape.

val parse_bool : string -> bool

val read_password : string -> string

val realpath : string -> string

Binding for nbdkit_realpath . Returns the canonical path from a path parameter.

val nanosleep : int -> int -> unit

Binding for nbdkit_nanosleep .  Sleeps for seconds and nanoseconds.

val export_name : unit -> string

Binding for nbdkit_export_name .  Returns the name of the export as requested by the client.

val shutdown : unit -> unit

Binding for nbdkit_shutdown .  Requests the server shut down.

val debug : ('a, unit, string, unit) Stdlib.format4 -> 'a

Print a debug message when nbdkit is in verbose mode.

val version : unit -> string

Return the version of nbdkit that the plugin was compiled with.

val peer_pid : unit -> int64

Binding for nbdkit_peer_pid .

val peer_uid : unit -> int64

Binding for nbdkit_peer_uid .

val peer_gid : unit -> int64

Binding for nbdkit_peer_gid .

nbdkit-ocaml-plugin(3), nbdkit-release-notes-1.24(1).