tests: Add a test script to cross-check loader config vs GRUB2

One can run this on a machine to validate things.  I'd like to
get this plugged into the actual OSTree tests as soon as we can
figure out how to sanely run grub2-generate as non-root in
our test suite.

Alternatively, this script can easily be run on a real install.

tests/grub2-entries-crosscheck.py

@@ -0,0 +1,105 @@
+#!/usr/bin/python
+#
+# Copyright (C) 2015 Red Hat
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+import os
+import sys
+
+if len(sys.argv) == 1:
+    loaderpath = '/boot/loader/entries'
+    grub2path = '/boot/grub2/grub.cfg'
+else:
+    loaderpath = sys.argv[1]
+    grub2path = sys.argv[2]
+
+def fatal(msg):
+    sys.stderr.write(msg)
+    sys.stderr.write('\n')
+    sys.exit(1)
+
+def compare_entries_descending(a, b):
+    return int(b['version']) - int(a['version'])
+
+def get_ostree_option(optionstring):
+    for o in optionstring.split():
+        if o.startswith('ostree='):
+            return o[8:]
+    raise ValueError('ostree= not found')
+            
+entries = []
+grub2_entries = []
+
+# Parse loader configs
+for fname in os.listdir(loaderpath):
+    path = os.path.join(loaderpath, fname)
+    with open(path) as f:
+        entry = {}
+        for line in f:
+            line = line.strip()
+            if (line == '' or line.startswith('#')):
+                continue
+            s = line.find(' ')
+            assert s > 0
+            k = line[0:s]
+            v = line[s+1:]
+            entry[k] = v
+        entries.append(entry)
+    entries.sort(compare_entries_descending)
+
+# Parse GRUB2 config
+with open(grub2path) as f:
+    in_ostree_config = False
+    grub2_entry = None
+    for line in f:
+        if line.startswith('### BEGIN /etc/grub.d/15_ostree ###'):
+            in_ostree_config = True
+        elif line.startswith('### END /etc/grub.d/15_ostree ###'): 
+            in_ostree_config = False
+            if grub2_entry is not None:
+                grub2_entries.append(grub2_entry)
+        elif in_ostree_config:
+            if line.startswith('menuentry '):
+                if grub2_entry is not None:
+                    grub2_entries.append(grub2_entry)
+                grub2_entry = {}
+            elif line.startswith('linux'):
+                parts = line.split()
+                grub2_entry['linux'] = parts[1]
+                grub2_entry['options'] = ' '.join(parts[2:])
+            elif line.startswith('initrd'):
+                grub2_entry['initrd'] = line.split()[1]
+
+if len(entries) != len(grub2_entries):
+    fatal("Found {0} loader entries, but {1} GRUB2 entries\n".format(len(entries), len(grub2_entries)))
+
+def assert_matches_key(a, b, key):
+    aval = a[key]
+    bval = b[key]
+    if aval != bval:
+        fatal("Mismatch on {0}: {1} != {2}".format(key, aval, bval))
+
+for i,(entry,grub2entry) in enumerate(zip(entries, grub2_entries)):
+    assert_matches_key(entry, grub2entry, 'linux')
+    assert_matches_key(entry, grub2entry, 'initrd')
+    entry_ostree = get_ostree_option(entry['options'])
+    grub2_ostree = get_ostree_option(grub2entry['options'])
+    if entry_ostree != grub2_ostree:
+        fatal("Mismatch on ostree option: {0} != {1}".format(entry_ostree, grub2_ostree))
+
+sys.stdout.write('GRUB2 configuration validated\n')
+sys.exit(0)