open Virt_df_gettext.Gettext
open Virt_df
-let probe_lvm2 (dev : device) =
- raise Not_found
+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 () =
- filesystem_type_register "LVM2" probe_lvm2
+ lvm_type_register plugin_name probe_pv list_lvs