(* Memory info command for virtual domains.
   (C) Copyright 2008 Richard W.M. Jones, Red Hat Inc.
   http://libvirt.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *)

open Printf

open Virt_mem_gettext.Gettext
open Virt_mem_utils
open Virt_mem_types

open Kernel_net_device

type linkage = Next | DevList of int

let rec find_net_devices debug image ksymmap kernel_version =
  if not (net_device_known kernel_version) then (
    eprintf (f_"%s: %s: unknown kernel version
Try a newer version of virt-mem, or if the guest is not from a
supported Linux distribution, see this page about adding support:
  http://et.redhat.com/~rjones/virt-mem/faq.html\n")
      image.domname kernel_version;
    image, None
  ) else (
    let size = net_device_size kernel_version in

    (* In kernels < around 2.6.22, this is a simple linked list:
     *   dev_base -> next -> next
     * In kernels >= 2.6.23, this is a list_head:
     *   dev_base_head -> list_head dev_list -> ...
     *)
    let linkage =
      let { field_available = available } =
	field_signature_of_net_device_next kernel_version in
      if available then
	Some Next
      else (
	let { field_available = available; field_offset = offset } =
	  field_signature_of_net_device_dev_list'next kernel_version in
	if available then
	  Some (DevList offset)
	else (
	  eprintf (f_"%s: kernel net_device table is not linked through either next pointer or dev_list list_head.  Cannot read net devices.\n") image.domname;
	  None
	)
      ) in
    match linkage with
    | None -> image, None

    | Some Next ->
	printf "linkage = Next\n%!";

	(* Linkage through old-style chain of next pointers. *)
	let dev_base =
	  try Some (Ksymmap.find "dev_base" ksymmap)
	  with Not_found ->
	    eprintf (f_"%s: could not find dev_base symbol in kernel image\n") image.domname;
	    None in
	(match dev_base with
	 | None -> image, None
	 | Some dev_base ->
	     do_next image kernel_version dev_base size
	);

    | Some (DevList offset) ->
	printf "linkage = DevList %d\n%!" offset;

	(* Linkage through new-style list_head dev_list. *)
	let dev_base_head =
	  try Some (Ksymmap.find "dev_base_head" ksymmap)
	  with Not_found ->
	    eprintf (f_"%s: could not find dev_base_head symbol in kernel image\n") image.domname;
	    None in
	(match dev_base_head with
	 | None -> image, None
	 | Some dev_base_head ->
	     let dev_base_head =
	       Virt_mem_mmap.follow_pointer image.mem dev_base_head in

	     do_dev_list image kernel_version dev_base_head offset size
	);
  )

(* Iterate dev_base_head -> list_head dev_list -> ... *)
and do_dev_list image kernel_version dev_base_head offset size =
  (* The list_head points into the middle of the structure.
   * Adjust this address to point to the start of the
   * structure.
   *)
  let addr = Int64.sub dev_base_head (Int64.of_int offset) in

  printf "do_dev_list, size = %d\n" size;

  let image =
    let rec loop image addr =
      let mapped = Virt_mem_mmap.is_mapped_range image.mem addr size in
      let image =
	if not mapped then
	  Virt_mem_types.load_memory image addr size
	else
	  image in
      let dev = get_net_device kernel_version image.mem addr in
      printf "net_device_name = %S\n" dev.net_device_name;
      let addr = Option.get dev.net_device_dev_list'next in
      if addr <> dev_base_head then
	loop image addr
      else
	image
    in
    loop image addr in
  image, Some dev_base_head

(* Iterate dev_base -> next -> next ... *)
and do_next image kernel_version addr size =
  printf "do_next, size = %d\n" size;

  let image =
    let rec loop image addr =
      if addr <> 0L then (
	let mapped = Virt_mem_mmap.is_mapped_range image.mem addr size in
	let image =
	  if not mapped then
	    Virt_mem_types.load_memory image addr size
	  else
	    image in
	let dev = get_net_device kernel_version image.mem addr in
      printf "net_device_name = %S\n" dev.net_device_name;
	let addr =
	  match dev.net_device_next with
	  | None -> assert false | Some addr -> addr in
	loop image addr
      ) else
	image
    in
    loop image addr in
  image, Some addr