Metadata parser.

[virt-top.git] / virt-df / virt_df_lvm2.ml

diff --git a/virt-df/virt_df_lvm2.ml b/virt-df/virt_df_lvm2.ml
index abc247e..fcf1fd2 100644 (file)
--- a/virt-df/virt_df_lvm2.ml
+++ b/virt-df/virt_df_lvm2.ml
@@ -24,20 +24,23 @@ open Printf
 open Virt_df_gettext.Gettext
 open Virt_df
 
+open Virt_df_lvm2_metadata
+
 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. *)
+(* Probe to see if it's an LVM2 PV. *)
 let rec probe_pv lvm_plugin_id dev =
   try
-    let uuid, metadata_offset, metadata_length = read_pv_label dev in
+    let uuid, _ = read_pv_label dev in
     if debug then
-      eprintf "LVM2 detected UUID %s md offset 0x%lx len %ld\n%!"
-       uuid metadata_offset metadata_length;
+      eprintf "LVM2 detected PV UUID %s\n%!" uuid;
     { lvm_plugin_id = lvm_plugin_id; pv_uuid = uuid }
-  with _ -> raise Not_found
+  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
@@ -47,7 +50,7 @@ and read_pv_label dev =
    *)
   let bits = dev#read_bitstring 0L (9 * sector_size) in
 
-  Bitmatch.hexdump_bitstring stdout bits;
+  (*Bitmatch.hexdump_bitstring stdout bits;*)
 
   bitmatch bits with
   | sector0 : sector_size*8 : bitstring; (* sector 0 *)
@@ -63,36 +66,78 @@ and read_pv_label dev =
     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
 
-    (* Check the metadata offset & length look reasonable for this
-     * device.  Otherwise maybe it's a newer or older header which
-     * we don't really understand properly.
+    (* Metadata offset is relative to end of PV label. *)
+    let metadata_offset = metadata_offset +* 0x1000_l in
+    (* Metadata length appears to include the trailing \000 which
+     * we don't want.
      *)
-    let () =
-      let size =
-       if dev#size <= Int64.of_int32 Int32.max_int then Int64.to_int32 dev#size
-       else Int32.max_int in
-      if metadata_offset < 0x1200_l || metadata_offset >= size
-       || metadata_length < 0_l || metadata_offset+*metadata_length >= size
-      then
-       invalid_arg "read_pv_label: bad metadata offset or length" in
+    let metadata_length = metadata_length -* 1_l in
 
-    Bitmatch.string_of_bitstring uuid, metadata_offset, metadata_length
+    let metadata = read_metadata dev metadata_offset metadata_length in
 
+    let uuid = Bitmatch.string_of_bitstring uuid in
+
+    uuid, metadata
 
   | _ ->
-    invalid_arg (sprintf "read_pv_label: %s: not an LVM2 physical volume"
-                  dev#name)
+    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 =
+let rec list_lvs devs =
+  (* Read the UUID and metadata (again) from each device to end up with
+   * an assoc list of PVs, keyed on the UUID.
+   *)
+  let pvs = List.map read_pv_label devs in
+
+  (* Parse the metadata using the external lexer/parser. *)
+  let pvs = List.map (
+    fun (uuid, metadata) ->
+      eprintf "parsing: %s\n<<<<\n" metadata;
+      uuid, Virt_df_lvm2_lexer.parse_lvm2_metadata_from_string metadata
+  ) pvs in
+
+  (* Print the parsed metadata. *)
+  List.iter (
+    fun (uuid, metadata) ->
+      eprintf "metadata for UUID %s:\n" uuid;
+      output_metadata stderr metadata
+  ) pvs;
+
   []
 
+
+
+
+
+  
+
 (* Register with main code. *)
 let () =
   lvm_type_register plugin_name probe_pv list_lvs