#!lua
--
-- Copyright (C) 2009 Free Software Foundation, Inc.
--
-- GRUB 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 3 of the License, or
-- (at your option) any later version.
--
-- GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
--

function bootiso (isofile)
  local err_no
  local err_msg

  local function print_error (msg)
    print ("Error: " .. msg)
    grub.run ("read")
  end

  local function find_file (folder, match)
    local filename

    local function enum_file (name)
      if (filename == nil) then
        filename = string.match (name, match)
      end
    end

    grub.enum_file (enum_file, folder)

    if (filename) then
      return folder .. "/" .. filename
    else
      return nil
    end
  end

  local function try_boot_generic ()
    local grubcfg = "(loop)/boot/grub/grub.cfg"

    if (grub.file_exist (grubcfg)) then
      grub.run ("configfile " .. grubcfg)
      return true
    end
    return false
  end

  local function try_boot_grml ()
    local linux = "(loop)/boot/grml/linux26"
    local initrd = "(loop)/boot/grml/initrd.gz"
    local params = "findiso=" .. isofile .. 
      " apm=power-off vga=791 quiet boot=live nomce"

    if (grub.file_exist ("(loop)/GRML/grml-version") and 
        grub.file_exist (linux) and 
        grub.file_exist (initrd)) then
      grub.run ("linux " .. linux .. " " .. params)
      grub.run ("initrd " .. initrd)
      return true
    end
    return false
  end

  local function try_boot_sidux ()
    local linux = find_file ("(loop)/boot", "vmlinuz%-.*%-sidux%-.*")
    local initrd = find_file ("(loop)/boot", "initrd%.img%-.*%-sidux%-.*")
    local params = "fromiso=" .. isofile .. " boot=fll quiet vga=791"

    if (linux and grub.file_exist (linux) and 
        initrd and grub.file_exist (initrd)) then
      grub.run ("linux " .. linux .. " " .. params)
      grub.run ("initrd " .. initrd)
      return true
    end
    return false
  end

  local function try_boot_ubuntu ()
    local linux = "(loop)/casper/vmlinuz"
    local initrd = "(loop)/casper/initrd.gz"
    local params = "boot=casper iso-scan/filename=" .. isofile .. 
      " quiet splash noprompt --"

    if (grub.file_exist ("(loop)/preseed/ubuntu.seed") and 
        grub.file_exist (linux) and 
        grub.file_exist (initrd)) then
      grub.run ("linux " .. linux .. " " .. params)
      grub.run ("initrd " .. initrd)
      return true
    end
    return false
  end

  if (isofile == nil) then
    print_error ("variable 'isofile' is undefined")
  elseif (not grub.file_exist (isofile)) then
    print_error ("file '" .. isofile .. "' does not exist")
  else
    err_no,err_msg = grub.run ("loopback loop " .. isofile)
    if (err_no ~= 0) then
      print_error ("Cannot load ISO: " .. err_msg)
    else
      if (try_boot_grml ()) then
      elseif (try_boot_sidux ()) then
      elseif (try_boot_ubuntu ()) then
      elseif (try_boot_generic ()) then
      else
        print_error ("Unsupported ISO type")
      end
    end
  end
end

bootiso (grub.getenv ("isofile"))