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(* 'df' command for virtual domains.
(C) Copyright 2007 Richard W.M. Jones, Red Hat Inc.
http://libvirt.org/
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Support for LVM2 PVs.
*)
open Printf
open Virt_df_gettext.Gettext
open Virt_df
let plugin_name = "LVM2"
let sector_size = 512
let sector_size64 = 512L
(* Probe to see if it's an LVM2 PV. Look for the "LABELONE" label. *)
let rec probe_pv lvm_plugin_id dev =
try
let uuid, _ = read_pv_label dev in
if debug then
eprintf "LVM2 detected PV UUID %s\n%!" uuid;
{ lvm_plugin_id = lvm_plugin_id; pv_uuid = uuid }
with exn ->
if debug then prerr_endline (Printexc.to_string exn);
raise Not_found
and read_pv_label dev =
(* Load the first 8 sectors. I found by experimentation that
* the second sector contains the header ("LABELONE" etc) and
* the nineth sector contains some additional information about
* the location of the current metadata.
*)
let bits = dev#read_bitstring 0L (9 * sector_size) in
(*Bitmatch.hexdump_bitstring stdout bits;*)
bitmatch bits with
| sector0 : sector_size*8 : bitstring; (* sector 0 *)
labelone : 8*8 : bitstring; (* "LABELONE" *)
padding : 16*8 : bitstring; (* Seems to contain something. *)
lvm2_ver : 8*8 : bitstring; (* "LVM2 001" *)
uuid : 32*8 : bitstring; (* UUID *)
padding2 : (sector_size-64)*8 : bitstring; (* to end of second sector *)
sector234567 : sector_size*8 * 6 : bitstring; (* sectors 2-6 *)
padding3 : 0x28*8 : bitstring; (* start of sector 8 *)
metadata_offset : 32 : littleendian;(* metadata offset *)
padding4 : 4*8 : bitstring;
metadata_length : 32 : littleendian (* length of metadata (bytes) *)
when Bitmatch.string_of_bitstring labelone = "LABELONE" &&
Bitmatch.string_of_bitstring lvm2_ver = "LVM2 001" ->
let metadata_offset = metadata_offset +* 0x1000_l in
let metadata = read_metadata dev metadata_offset metadata_length in
(*prerr_endline metadata;*)
let uuid = Bitmatch.string_of_bitstring uuid in
uuid, metadata
| _ ->
invalid_arg
(sprintf "LVM2: read_pv_label: %s: not an LVM2 physical volume" dev#name)
and read_metadata dev offset32 len32 =
if debug then
eprintf "metadata: offset 0x%lx len %ld bytes\n" offset32 len32;
(* Check the offset and length are sensible. *)
let offset64 =
if offset32 <= Int32.max_int then Int64.of_int32 offset32
else invalid_arg "LVM2: read_metadata: metadata offset too large" in
let len64 =
if len32 <= 2_147_483_647_l then Int64.of_int32 len32
else invalid_arg "LVM2: read_metadata: metadata length too large" in
if offset64 <= 0x1200L || offset64 >= dev#size
|| len64 <= 0L || offset64 +^ len64 >= dev#size then
invalid_arg "LVM2: read_metadata: bad metadata offset or length";
(* If it is outside the disk boundaries, this will throw an exception,
* otherwise it will read and return the metadata string.
*)
dev#read offset64 (Int64.to_int len64)
(* We are passed a list of devices which we previously identified
* as PVs belonging to us. From these produce a list of all LVs
* (as devices) and return them. Note that we don't try to detect
* what is on these LVs - that will be done in the main code.
*)
let list_lvs devs =
[]
(* Register with main code. *)
let () =
lvm_type_register plugin_name probe_pv list_lvs
|
