Add PV detection framework.

3 files changed, 61 insertions, 21 deletions

diff --git a/virt-df/virt_df.ml b/virt-df/virt_df.ml
index c61f6df..b992e1b 100644
--- a/virt-df/virt_df.ml
+++ b/virt-df/virt_df.ml
@@ -97,7 +97,7 @@ and disk_content =
   [ `Unknown				(* Not probed or unknown. *)
   | `Partitions of partitions		(* Contains partitions. *)
   | `Filesystem of filesystem		(* Contains a filesystem directly. *)
-  | `PhysicalVolume of unit		(* Contains an LVM PV. *)
+  | `PhysicalVolume of string		(* Contains an LVM PV. *)
   ]
 
 (* Partitions. *)
@@ -116,7 +116,7 @@ and partition_status = Bootable | Nonbootable | Malformed | NullEntry
 and partition_content =
   [ `Unknown				(* Not probed or unknown. *)
   | `Filesystem of filesystem		(* Filesystem. *)
-  | `PhysicalVolume of unit		(* Contains an LVM PV. *)
+  | `PhysicalVolume of string		(* Contains an LVM PV. *)
   ]
 
 (* Filesystems (also swap devices). *)
@@ -180,8 +180,8 @@ let filesystem_types = ref []
 let filesystem_type_register (fs_name : string) probe_fn =
   filesystem_types := (fs_name, probe_fn) :: !filesystem_types
 
-(* Probe a device for filesystems.  Returns [Some fs] or [None]. *)
-let probe_for_filesystems dev =
+(* Probe a device for a filesystem.  Returns [Some fs] or [None]. *)
+let probe_for_filesystem dev =
   if debug then eprintf "probing for a filesystem on %s ...\n%!" dev#name;
   let rec loop = function
     | [] -> None
@@ -200,8 +200,23 @@ let probe_for_filesystems dev =
   r
 
 (* Register a volume management type. *)
-(*
 let lvm_types = ref []
-let lvm_type_register (lvm_name : string) probe_fn =
-  lvm_types := (lvm_name, probe_fn) :: !lvm_types
-*)
+let lvm_type_register (lvm_name : string) probe_fn list_lvs_fn =
+  lvm_types := (lvm_name, (probe_fn, list_lvs_fn)) :: !lvm_types
+
+(* Probe a device for a PV.  Returns [Some lvm_name] or [None]. *)
+let probe_for_pv dev =
+  if debug then eprintf "probing if %s is a PV ...\n%!" dev#name;
+  let rec loop = function
+    | [] -> None
+    | (lvm_name, (probe_fn, _)) :: rest ->
+	if probe_fn dev then Some lvm_name else loop rest
+  in
+  let r = loop !lvm_types in
+  if debug then (
+    match r with
+    | None -> eprintf "no PV found on %s\n%!" dev#name
+    | Some lvm_name ->
+	eprintf "%s contains a %s PV\n%!" dev#name lvm_name
+  );
+  r
diff --git a/virt-df/virt_df.mli b/virt-df/virt_df.mli
index 1b3f6ca..db98af2 100644
--- a/virt-df/virt_df.mli
+++ b/virt-df/virt_df.mli
@@ -17,9 +17,9 @@
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  *)
 
-(* This module (Virt_df) contains functions and values which are
- * used throughout the plug-ins and main code.
- *)
+(** This module (Virt_df) contains functions and values which are
+    used throughout the plug-ins and main code.
+*)
 
 val debug : bool
 (** If true, emit logs of debugging information to stderr. *)
@@ -71,7 +71,7 @@ v}
    of the physical devices, partitions and filesystems potentially
    available to the guest.
     
-   Volume management schemes (eg. LVM) register themselves here
+   Volume management schemes (eg. LVM2) register themselves here
    and are called later with "spare" physical devices and partitions
    to see if they contain LVM data.  If this results in additional
    logical volumes then these are checked for filesystems.
@@ -131,7 +131,7 @@ and disk = {
 and disk_content =
     [ `Filesystem of filesystem		(** Contains a direct filesystem. *)
     | `Partitions of partitions		(** Contains partitions. *)
-    | `PhysicalVolume of unit		(** Contains an LVM PV. *)
+    | `PhysicalVolume of string		(** Contains an LVM PV. *)
     | `Unknown				(** Not probed or unknown. *)
     ]
 and partitions = {
@@ -147,7 +147,7 @@ and partition = {
 and partition_status = Bootable | Nonbootable | Malformed | NullEntry
 and partition_content =
     [ `Filesystem of filesystem		(** Filesystem. *)
-    | `PhysicalVolume of unit		(** Contains an LVM PV. *)
+    | `PhysicalVolume of string		(** Contains an LVM PV. *)
     | `Unknown				(** Not probed or unknown. *)
     ]
 and filesystem = {
@@ -177,5 +177,17 @@ val probe_for_partitions : device -> partitions option
 val filesystem_type_register : string -> (device -> filesystem) -> unit
 (** Register a filesystem probing plugin. *)
 
-val probe_for_filesystems : device -> filesystem option
+val probe_for_filesystem : device -> filesystem option
 (** Do a filesystem probe on a device.  Returns [Some filesystem] or [None]. *)
+
+val lvm_type_register :
+  string -> (device -> bool) -> (device list -> device list) -> unit
+(** [lvm_type_register lvm_name probe_fn list_lvs_fn]
+    registers a new LVM type.  [probe_fn] is a function which
+    should probe a device to find out if it contains a PV.
+    [list_lvs_fn] is a function which should take a list of
+    devices (PVs) and construct a list of LV devices.
+*)
+
+val probe_for_pv : device -> string option
+(** Do a PV probe on a device.  Returns [Some lvm_name] or [None]. *)
diff --git a/virt-df/virt_df_main.ml b/virt-df/virt_df_main.ml
index 9504785..c989d76 100644
--- a/virt-df/virt_df_main.ml
+++ b/virt-df/virt_df_main.ml
@@ -268,13 +268,18 @@ OPTIONS" in
 	  { disk with d_content = `Partitions parts }
       | None ->
 	  (* Not partitioned.  Does it contain a filesystem? *)
-	  let fs = probe_for_filesystems dev in
+	  let fs = probe_for_filesystem dev in
 	  match fs with
 	  | Some fs ->
 	      { disk with d_content = `Filesystem fs }
 	  | None ->
-	      (* Not partitioned, no filesystem, so it's spare. *)
-	      disk
+	      (* Not partitioned, no filesystem, is it a PV? *)
+	      let pv = probe_for_pv dev in
+	      match pv with
+	      | Some lvm_name ->
+		  { disk with d_content = `PhysicalVolume lvm_name }
+	      | None ->
+		  disk (* Spare/unknown. *)
   ) in
 
   (* Now we have either detected partitions or a filesystem on each
@@ -287,12 +292,18 @@ OPTIONS" in
 	let ps = List.map (
 	  fun p ->
 	    if p.part_status = Bootable || p.part_status = Nonbootable then (
-	      let fs = probe_for_filesystems p.part_dev in
+	      let fs = probe_for_filesystem p.part_dev in
 	      match fs with
 	      | Some fs ->
 		  { p with part_content = `Filesystem fs }
 	      | None ->
-		  p
+		  (* Is it a PV? *)
+		  let pv = probe_for_pv p.part_dev in
+		  match pv with
+		  | Some lvm_name ->
+		      { p with part_content = `PhysicalVolume lvm_name }
+		  | None ->
+		      p (* Spare/unknown. *)
 	    ) else p
 	) parts.parts in
 	let parts = { parts with parts = ps } in
@@ -300,7 +311,9 @@ OPTIONS" in
     | disk -> disk
   ) in
 
-  (* XXX LVM stuff here. *)
+  (* XXX LVM filesystem detection ... *)
+
+