Add xenvm host-dump <VG> <host> to dump the metadata volumes

This will create 2 files in the current directory:

<host>-fromLVM
<host>-toLVM

Signed-off-by: David Scott <[email protected]>

Author: David Scott

xenvm/lvdump.ml

@@ -5,6 +5,39 @@ open Lwt
 open Xenvm_common
 open Errors
 
+module Vg_IO = Lvm.Vg.Make(Log)(Block)(Time)(Clock)
+
+let to_file (vg_name, lv_name) local_device oc =
+  with_block local_device
+    (fun x ->
+      Vg_IO.connect [ x ] `RO >>|= fun vg ->
+      match Vg_IO.find vg lv_name with
+      | None -> failwith (Printf.sprintf "Failed to find LV %s" lv_name)
+      | Some vol ->
+      Vg_IO.Volume.connect vol
+      >>= function
+      | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" lv_name))
+      | `Ok disk ->
+        Vg_IO.Volume.get_info disk
+        >>= fun info ->
+        let buffer = Io_page.(to_cstruct (get 1024)) in
+        let nsectors = Cstruct.len buffer / info.Vg_IO.Volume.sector_size in
+        let rec loop = function
+          | n when n = info.Vg_IO.Volume.size_sectors -> return ()
+          | n ->
+            let remaining = Int64.sub info.Vg_IO.Volume.size_sectors n in
+            let toread = min (Int64.to_int remaining) nsectors in
+            let buffer' = Cstruct.sub buffer 0 (toread * info.Vg_IO.Volume.sector_size) in
+            Vg_IO.Volume.read disk n [ buffer' ]
+            >>= function
+            | `Ok () ->
+              Lwt_io.write oc (Cstruct.to_string buffer')
+              >>= fun () ->
+              loop (Int64.(add n (of_int toread)))
+            | _ -> failwith (Printf.sprintf "Failed to read sector %Ld" n) in
+        loop 0L
+    )
+
 let lvdump copts (vg_name, lv_name_opt) physical_device : unit =
   let open Xenvm_common in
   let lv_name = match lv_name_opt with Some l -> l | None -> failwith "Need LV name" in
@@ -15,37 +48,8 @@ let lvdump copts (vg_name, lv_name_opt) physical_device : unit =
       | _, Some d -> d (* cmdline overrides default for the VG *)
       | Some info, None -> info.local_device (* If we've got a default, use that *)
       | None, None -> failwith "Need to know the local device!" in
-    let module Vg_IO = Lvm.Vg.Make(Log)(Block)(Time)(Clock) in
-    with_block local_device
-      (fun x ->
-        Vg_IO.connect [ x ] `RO >>|= fun vg ->
-        match Vg_IO.find vg lv_name with
-        | None -> failwith (Printf.sprintf "Failed to find LV %s" lv_name)
-        | Some vol ->
-        Vg_IO.Volume.connect vol
-        >>= function
-        | `Error _ -> fail (Failure (Printf.sprintf "Failed to open %s" lv_name))
-        | `Ok disk ->
-          Vg_IO.Volume.get_info disk
-          >>= fun info ->
-          let buffer = Io_page.(to_cstruct (get 1024)) in
-          let nsectors = Cstruct.len buffer / info.Vg_IO.Volume.sector_size in
-          let rec loop = function
-            | n when n = info.Vg_IO.Volume.size_sectors -> return ()
-            | n ->
-              let remaining = Int64.sub info.Vg_IO.Volume.size_sectors n in
-              let toread = min (Int64.to_int remaining) nsectors in
-              let buffer' = Cstruct.sub buffer 0 (toread * info.Vg_IO.Volume.sector_size) in
-              Vg_IO.Volume.read disk n [ buffer' ]
-              >>= function
-              | `Ok () ->
-                Lwt_io.write Lwt_io.stdout (Cstruct.to_string buffer')
-                >>= fun () ->
-                loop (Int64.(add n (of_int toread)))
-              | _ -> failwith (Printf.sprintf "Failed to read sector %Ld" n) in
-          loop 0L
-      )
-    )
+    to_file (vg_name, lv_name) local_device Lwt_io.stdout
+  )
 
 let lvdump_cmd =
   let doc = "Dump the physical contents of a logical volume" in

xenvm/xenvm.ml

@@ -184,6 +184,23 @@ let host_disconnect copts (vg_name,_) uncooperative host =
     set_uri copts info;
     Client.Host.disconnect ~cooperative:(not uncooperative) ~name:host in
   Lwt_main.run t 
+let host_dump copts (vg_name,_) physical_device host =
+  let t =
+    get_vg_info_t copts vg_name >>= fun info ->
+    set_uri copts info;
+    let local_device : string = match (info,physical_device) with
+      | _, Some d -> d (* cmdline overrides default for the VG *)
+      | Some info, None -> info.local_device (* If we've got a default, use that *)
+      | None, None -> failwith "Need to know the local device!" in
+    Client.Host.all ()
+    >>= fun all ->
+    let open Xenvm_interface in
+    let h = List.find (fun h -> h.name = host) all in
+    Lwt_io.with_file Lwt_io.Output h.toLVM.lv (Lvdump.to_file (vg_name, h.toLVM.lv) local_device)
+    >>= fun () ->
+    Lwt_io.with_file Lwt_io.Output h.fromLVM.lv (Lvdump.to_file (vg_name, h.fromLVM.lv) local_device) in
+  Lwt_main.run t 
+
 let host_destroy copts (vg_name,_) host =
   let t =
     get_vg_info_t copts vg_name >>= fun info ->
@@ -399,6 +416,15 @@ let host_disconnect_cmd =
   Term.(pure host_disconnect $ copts_t $ name_arg $ uncooperative_flag $ hostname),
   Term.info "host-disconnect" ~sdocs:copts_sect ~doc ~man
 
+let host_dump_cmd =
+  let doc = "Dump a host's metadata volumes" in
+  let man = [
+    `S "DESCRIPTION";
+    `P "Copy the contents of a host's metadata volumes to local files in the current directory for forensic analysis.";
+  ] in
+  Term.(pure host_dump $ copts_t $ name_arg $ physical_device_arg $ hostname),
+  Term.info "host-dump" ~sdocs:copts_sect ~doc ~man
+
 let host_create_cmd =
   let doc = "Initialise a host's metadata volumes" in
   let man = [
@@ -462,7 +488,10 @@ let cmds = [
   dump_cmd;
   shutdown_cmd; host_create_cmd; host_destroy_cmd;
   host_list_cmd;
-  host_connect_cmd; host_disconnect_cmd; benchmark_cmd;
+  host_connect_cmd;
+  host_disconnect_cmd;
+  host_dump_cmd;
+  benchmark_cmd;
   Lvcreate.lvcreate_cmd;
   Lvchange.lvchange_cmd;
   Vgchange.vgchange_cmd;