From 03077403d291bbdadd6e0485e73870db234b28a2 Mon Sep 17 00:00:00 2001
From: Shinji Suzuki <shinji.suzuki@gmail.com>
Date: Tue, 20 Mar 2018 14:08:58 +0900
Subject: [PATCH] Fix regression introduced by
 8ea5932bdcd706d7ca4c8b44aa7b0a424daec59d. With the change in the commit,
 loopback.cfg got regenerated at the location of file determined by scanning
 iso tree. If no loopback.cfg was found, it was assumed to be at the
 distribution root directory. In either case, loopback.cfg was
 generated/overwritten at the determined location and the file was chosen for
 booting. Now, if no loopback.cfg is found, grub.cfg is sought. It is only in
 the case where neither is found that loopback.cfg gets generated and used.
 Therefore no config files provided by distro get overwritten.

---
 scripts/grub.py | 149 +++++++++++++++++++-----------------------------
 scripts/iso.py  |   4 ++
 2 files changed, 64 insertions(+), 89 deletions(-)

diff --git a/scripts/grub.py b/scripts/grub.py
index 37647cf..fccb1ec 100644
--- a/scripts/grub.py
+++ b/scripts/grub.py
@@ -20,60 +20,68 @@ def mbusb_update_grub_cfg():
     Function to update grub.cfg file to support UEFI/EFI systems
     :return:
     """
-    # Lets convert syslinux config file to grub2 accepted file format.
+
     install_dir = os.path.join(config.usb_mount, 'multibootusb',
                                iso.iso_basename(config.image_path))
-
-    # First write custom loopback.cfg file so as to be detected by iso2grub2 function later.
-
-    # There may be more than one loopback.cfg but we just need to fix
-    # one and that is goingn to be referenced in mbusb's grub.cfg.
-    loopback_cfg_path = iso.iso_file_path(config.image_path, 'loopback.cfg')
-    if not loopback_cfg_path:
-        loopback_cfg_path = 'loopback.cfg'
-
-    wrote_custom_cfg = write_custom_grub_cfg(install_dir, loopback_cfg_path)
-
-    # Try to generate loopback entry file from syslinux config files
-    try:
-        gen.log('Trying to create loopback.cfg')
-        iso2_grub2_cfg = iso2grub2(install_dir, loopback_cfg_path,
-                                   wrote_custom_cfg)
-    except Exception as e:
-        print(e)
-        gen.log(e)
-        gen.log('Error converting syslinux cfg to grub2 cfg', error=True)
-        iso2_grub2_cfg = False
-
     grub_cfg_path = None
     syslinux_menu = None
-#     sys_cfg_path = None
-    mbus_grub_cfg_path = os.path.join(config.usb_mount, 'multibootusb', 'grub', 'grub.cfg')
-#     iso_grub_cfg = iso.iso_file_path(config.image_path, 'grub.cfg')
-    if iso.isolinux_bin_dir(config.image_path) is not False:
-        iso_sys_cfg_path = os.path.join(iso.isolinux_bin_dir(config.image_path), 'syslinux.cfg')
-        iso_iso_cfg_path = os.path.join(iso.isolinux_bin_dir(config.image_path), 'isolinux.cfg')
-
-        if os.path.exists(os.path.join(config.usb_mount, 'multibootusb', iso.iso_basename(config.image_path),
-                                       iso_sys_cfg_path)):
-            syslinux_menu = iso_sys_cfg_path.replace('\\', '/')
-        elif os.path.exists(os.path.join(config.usb_mount, 'multibootusb', iso.iso_basename(config.image_path),
-                                         iso_iso_cfg_path)):
-            syslinux_menu = iso_iso_cfg_path.replace('\\', '/')
-
-    efi_grub_cfg = get_grub_cfg(config.image_path)
-    boot_grub_cfg = get_grub_cfg(config.image_path, efi=False)
-
-    if loopback_cfg_path is not False:
-        grub_cfg_path = loopback_cfg_path.replace('\\', '/')
-    elif efi_grub_cfg is not False:
-        grub_cfg_path = efi_grub_cfg.replace('\\', '/')
-    elif boot_grub_cfg is not False:
-        grub_cfg_path = boot_grub_cfg.replace('\\', '/')
-    elif iso2_grub2_cfg is not False:
-        grub_cfg_path = iso2_grub2_cfg.replace('\\', '/')
-    #elif bootx_64_cfg is not False:
-    #    grub_cfg_path = bootx_64_cfg.replace('\\', '/')
+    mbus_grub_cfg_path = os.path.join(config.usb_mount, 'multibootusb',
+                                      'grub', 'grub.cfg')
+    isobin_dir = iso.isolinux_bin_dir(config.image_path)
+    if isobin_dir is not False:
+        for name in ['syslinux.cfg', 'isolinux.cfg']:
+            cfg_path = os.path.join(isobin_dir, name)
+            cfg_fullpath = os.path.join(install_dir, cfg_path)
+            if os.path.exists(cfg_fullpath):
+                syslinux_menu = cfg_path.replace('\\', '/')
+                break
+
+    # Decide which grub config file to boot by.
+    loopback_cfg_list = iso.get_file_list(
+        config.image_path,
+        lambda x: os.path.basename(x).lower()=='loopback.cfg')
+    grub_cfg_list = iso.get_file_list(
+        config.image_path,
+        lambda x: os.path.basename(x).lower().startswith('grub') and
+        os.path.basename(x).lower().endswith('.cfg'))
+    candidates = []
+    for src_list, predicate in [
+            # List in the order of decreasing preference.
+            (loopback_cfg_list, lambda x: 'efi' in x.lower()),
+            (loopback_cfg_list, lambda x: 'boot' in x.lower()),
+            (grub_cfg_list, lambda x: 'efi' in x.lower()),
+            (grub_cfg_list, lambda x: 'boot' in x.lower()),
+            (loopback_cfg_list,
+             lambda x: 'efi' not in x.lower() and 'boot' not in x.lower()),
+            (grub_cfg_list,
+             lambda x: 'efi' not in x.lower() and 'boot' not in x.lower())]:
+        sub_candidates = [x for x in src_list if predicate(x)]
+        if len(sub_candidates):
+            candidates.append(sub_candidates[0])
+            # We could 'break' here but will let the iteration continue
+            # in order to lower the chance of keeping latent bugs.
+
+    if 0<len(candidates):
+        grub_cfg_path = candidates[0].replace('\\', '/')
+    else :
+        # No suitable grub configuration file is provided by distro.
+        # Lets convert syslinux config files to grub2 accepted file format.
+        new_loopback_here = 'loopback.cfg'
+        try:
+            # First write custom loopback.cfg file so as to be detected
+            # by iso2grub2 function later.
+            write_custom_grub_cfg(install_dir, new_loopback_here)
+            gen.log('Trying to create loopback.cfg')
+            iso2grub2(install_dir, new_loopback_here)
+        except Exception as e:
+            new_loopback_here = None
+            gen.log(e)
+            gen.log('Error converting syslinux cfg to grub2 cfg', error=True)
+        if new_loopback_here:
+            grub_cfg_path = new_loopback_here.replace('\\', '/')
+        #elif bootx_64_cfg is not False:
+        #    grub_cfg_path = bootx_64_cfg.replace('\\', '/')
+    gen.log("Using %s to boot this distro." % grub_cfg_path)
 
     if os.path.exists(mbus_grub_cfg_path):
         gen.log('Updating grub.cfg file...')
@@ -137,35 +145,6 @@ def write_custom_grub_cfg(install_dir, loopback_cfg_path):
         return False
 
 
-def get_grub_cfg(iso_link, efi=True):
-    """
-    Detects path to "grub.cfg" file from ISO file. Default is to get from EFI directory.
-    :return: path of "grub.cfg" file as string.
-    """
-    if os.path.exists(iso_link):
-        grub_path = False
-        iso_file_list = _7zip.list_iso(iso_link)
-        if any("grub" in s.lower() for s in iso_file_list):
-            for f in iso_file_list:
-                f_basename = os.path.basename(f).lower()
-                if f_basename.startswith('grub') and f_basename.endswith('.cfg'):
-                #if 'grub.cfg' in f.lower():
-                    if efi is True:
-                        if 'efi' in f.lower():
-                            grub_path = f.replace('\\', '/')
-                            gen.log('Found ' + grub_path)
-                            break
-                        elif 'boot' in f.lower():
-                            grub_path = f.replace('\\', '/')
-                            gen.log('Found ' + grub_path)
-                            break
-                        else:
-                            grub_path = f.replace('\\', '/')
-                            gen.log('Found ' + grub_path)
-                            break
-        return grub_path
-
-
 def grub_custom_menu(mbus_grub_cfg_path, distro):
     iso_size_mb = bytes2human(iso.iso_size(config.image_path))
     gen.log('size of the ISO is ' + str(iso_size_mb))
@@ -279,7 +258,7 @@ def extract_initrd_param(value, isolinux_dir):
     return  initrd_line, ' '.join(others)
 
 
-def iso2grub2(install_dir, loopback_cfg_path, wrote_custom_cfg):
+def iso2grub2(install_dir, loopback_cfg_path):
     """
     Function to convert syslinux configuration to grub2 accepted configuration format. Features implemented are similar
     to that of grub2  'loopback.cfg'. This 'loopback.cfg' file can be later on caled directly from grub2. The main
@@ -293,14 +272,6 @@ def iso2grub2(install_dir, loopback_cfg_path, wrote_custom_cfg):
         install_dir, loopback_cfg_path.lstrip(r'\/'))
 
     gen.log('loopback.cfg file is set to ' + loopback_cfg_path)
-    # Comment-out the previous content if write_custom_grub_cfg() did nothing.
-    if os.path.exists(loopback_cfg_path) and not wrote_custom_cfg:
-        with open(loopback_cfg_path, 'r') as f:
-            lines = f.readlines()
-        with open(loopback_cfg_path, 'w') as f:
-            f.write('##### Previous content is kept from here.\n')
-            f.write( ''.join('#'+s for s in lines))
-            f.write('##### to here.\n\n')
 
     iso_bin_dir = iso.isolinux_bin_dir(config.image_path)
     seen_menu_lines = []
@@ -430,7 +401,7 @@ def iso2grub2(install_dir, loopback_cfg_path, wrote_custom_cfg):
     if os.path.exists(loopback_cfg_path):
         gen.log(
             'loopback.cfg file is successfully created.\nYou must send this file for debugging if something goes wrong.')
-        return 'loopback.cfg'
+        return loopback_cfg_path
     else:
         gen.log('Failed to convert syslinux config file to loopback.cfg')
         return False
diff --git a/scripts/iso.py b/scripts/iso.py
index 5f21d0b..2393174 100644
--- a/scripts/iso.py
+++ b/scripts/iso.py
@@ -209,6 +209,10 @@ def iso_file_path(iso_link, file_name):
 
     return file_path
 
+def get_file_list(iso_link, predicate):
+    # Note that unlike iso_file_path(), only the basename is checked.
+    return [f for f in _7zip.list_iso(iso_link) if predicate(f)]
+
 if __name__ == '__main__':
     #iso_path = '../../../DISTROS/2016/debian-live-8.3.0-amd64-lxde-desktop.iso'
     iso_path = '../../../DISTROS/2015/super_grub2_disk_hybrid_2.02s3.iso'