debian/python/UEFI/Filesystems.py

   1 #
   2 # Copyright 2019-2021 Canonical Ltd.
   3 # Authors:
   4 # - dann frazier <dann.frazier@canonical.com>
   5 #
   6 # This program is free software: you can redistribute it and/or modify it
   7 # under the terms of the GNU General Public License version 3, as published
   8 # by the Free Software Foundation.
   9 #
  10 # This program is distributed in the hope that it will be useful, but WITHOUT
  11 # ANY WARRANTY; without even the implied warranties of MERCHANTABILITY,
  12 # SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 # General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License along with
  16 # this program.  If not, see <http://www.gnu.org/licenses/>.
  17 #
  18
  19 import os
  20 import shutil
  21 import subprocess
  22 import tempfile
  23
  24
  25 class FatFsImage:
  26     def __init__(self, size_in_mb):
  27         with tempfile.NamedTemporaryFile(delete=False) as f:
  28             self.path = f.name
  29
  30         subprocess.check_call(
  31             [
  32                 'dd', 'if=/dev/zero', 'of=%s' % (self.path),
  33                 'count=0', 'bs=1M', 'seek=%d' % (size_in_mb), 'status=none'
  34             ]
  35         )
  36         new_env = os.environ.copy()
  37         new_env['PATH'] = f"{os.environ['PATH']}:/sbin"
  38         subprocess.check_call(['mkdosfs', '-F', '32', self.path], env=new_env)
  39
  40     def __del__(self):
  41         os.unlink(self.path)
  42
  43     def mkdir(self, dir):
  44         subprocess.run(['mmd', '-i', self.path, dir])
  45
  46     def makedirs(self, dir):
  47         dirs = dir.split(os.path.sep)
  48         for dir_idx in range(1, len(dirs)+1):
  49             next_dir = os.path.sep.join(dirs[:dir_idx])
  50             self.mkdir(next_dir)
  51
  52     def insert_file(self, src, dest):
  53         subprocess.check_call(
  54             [
  55                 'mcopy', '-i', self.path, src, '::%s' % (dest)
  56             ]
  57         )
  58
  59
  60 class EfiBootableIsoImage:
  61     def __init__(self, eltorito_img):
  62         with tempfile.TemporaryDirectory() as iso_root:
  63             eltorito_iso_root = 'boot'
  64             eltorito_iso_path = os.path.join(eltorito_iso_root, 'efi.img')
  65             eltorito_local_root = os.path.join(iso_root, eltorito_iso_root)
  66             eltorito_local_path = os.path.join(iso_root, eltorito_iso_path)
  67
  68             os.makedirs(eltorito_local_root)
  69             shutil.copyfile(eltorito_img.path, eltorito_local_path)
  70
  71             with tempfile.NamedTemporaryFile(delete=False) as f:
  72                 self.path = f.name
  73
  74             subprocess.check_call(
  75                 [
  76                     'xorriso', '-as', 'mkisofs', '-J', '-l',
  77                     '-c', 'boot/boot.cat',
  78                     '-partition_offset', '16', '-append_partition', '2',
  79                     '0xef', eltorito_local_path,
  80                     '-e', '--interval:appended_partition_2:all::',
  81                     '-no-emul-boot', '-o', self.path, iso_root
  82                 ]
  83             )
  84
  85     def __del__(self):
  86         os.unlink(self.path)
  87
  88
  89 class GrubShellBootableIsoImage(EfiBootableIsoImage):
  90     def __init__(self, efi_arch, use_signed):
  91         EfiArchToGrubArch = {
  92             'X64': "x86_64",
  93             'AA64': "arm64",
  94         }
  95         efi_img = FatFsImage(64)
  96         efi_img.makedirs(os.path.join('EFI', 'BOOT'))
  97         removable_media_path = os.path.join(
  98             'EFI', 'BOOT', 'BOOT%s.EFI' % (efi_arch.upper())
  99         )
 100         efi_ext = 'efi'
 101         grub_subdir = "%s-efi" % EfiArchToGrubArch[efi_arch.upper()]
 102         if use_signed:
 103             efi_ext = "%s.signed" % (efi_ext)
 104             grub_subdir = "%s-signed" % (grub_subdir)
 105
 106         shim_src = os.path.join(
 107             os.path.sep, 'usr', 'lib', 'shim',
 108             'shim%s.%s' % (efi_arch.lower(), efi_ext)
 109         )
 110         grub_src = os.path.join(
 111             os.path.sep, 'usr', 'lib', 'grub',
 112             '%s' % (grub_subdir),
 113             "" if use_signed else "monolithic",
 114             'grub%s.%s' % (efi_arch.lower(), efi_ext)
 115         )
 116         grub_dest = os.path.join(
 117             'EFI', 'BOOT', 'GRUB%s.EFI' % (efi_arch.upper())
 118         )
 119         efi_img.insert_file(shim_src, removable_media_path)
 120         efi_img.insert_file(grub_src, grub_dest)
 121         super().__init__(efi_img)