CP-308455 VM.sysprep if CD insert fails, remove ISO (#6632)

If inserting the CD fails, remove the ISO to protect its contents.
Likewise, remove it when eject fails.

Author: lindig

ocaml/xapi/vm_sysprep.ml

@@ -29,6 +29,7 @@ type error =
   | Other of string
   | VM_CDR_not_found
   | VM_CDR_eject
+  | VM_CDR_insert
   | VM_misses_feature
   | VM_not_running
   | VM_sysprep_timeout
@@ -212,6 +213,8 @@ let eject ~rpc ~session_id ~vbd ~iso =
     Client.VBD.eject ~rpc ~session_id ~vbd ;
     Sys.remove iso
   with exn ->
+    Sys.remove iso ;
+    (* still remove ISO to protect it *)
     warn "%s: ejecting CD failed: %s" __FUNCTION__ (Printexc.to_string exn) ;
     fail VM_CDR_eject
 
@@ -281,7 +284,13 @@ let sysprep ~__context ~vm ~unattend ~timeout =
   let uuid = Db.VDI.get_uuid ~__context ~self:vdi in
   debug "%s: inserting Sysprep VDI for VM %s" __FUNCTION__ vm_uuid ;
   call ~__context @@ fun rpc session_id ->
-  Client.VBD.insert ~rpc ~session_id ~vdi ~vbd ;
+  ( try Client.VBD.insert ~rpc ~session_id ~vdi ~vbd
+    with e ->
+      debug "%s: failed to insert CD, removing ISO %s: %s" __FUNCTION__ iso
+        (Printexc.to_string e) ;
+      Sys.remove iso ;
+      fail VM_CDR_insert
+  ) ;
   Thread.delay !Xapi_globs.vm_sysprep_wait ;
   match trigger ~rpc ~session_id ~domid ~uuid ~timeout ~vbd ~iso with
   | true ->

ocaml/xapi/vm_sysprep.mli

@@ -18,6 +18,7 @@ type error =
   | Other of string
   | VM_CDR_not_found
   | VM_CDR_eject
+  | VM_CDR_insert
   | VM_misses_feature
   | VM_not_running
   | VM_sysprep_timeout

ocaml/xapi/xapi_vm.ml

@@ -1727,10 +1727,13 @@ let sysprep ~__context ~self ~unattend ~timeout =
       raise Api_errors.(Server_error (sysprep, [uuid; "VM is not running"]))
   | exception Vm_sysprep.Sysprep VM_CDR_eject ->
       raise Api_errors.(Server_error (sysprep, [uuid; "VM failed to eject CD"]))
+  | exception Vm_sysprep.Sysprep VM_CDR_insert ->
+      raise Api_errors.(Server_error (sysprep, [uuid; "VM failed to insert CD"]))
   | exception Vm_sysprep.Sysprep VM_sysprep_timeout ->
       raise
         Api_errors.(
-          Server_error (sysprep, [uuid; "sysprep not found running - timeout"])
+          Server_error
+            (sysprep, [uuid; "No response from sysprep within allocated time"])
         )
   | exception Vm_sysprep.Sysprep XML_too_large ->
       raise