CP-308428: bootloader: Add support for xen_boot entry type

A GRUB2 menu entry may boot different OSes using different loaders.

Add a new menu entry parameter to allow specifying the entry type:

1) multiboot2 - used for booting xen.gz
2) linux - used for booting native Linux
3) xen_boot - used for booting xen.efi, newly introduced here

The entry type can be specified when first creating the menu entry
(defaulting to multiboot2) and it is subsequently maintained when
reading/writing the config file.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>

Author: rosslagerwall

tests/test_bootloader.py

@@ -4,7 +4,7 @@
 import subprocess
 from tempfile import NamedTemporaryFile, mkdtemp
 
-from xcp.bootloader import Bootloader
+from xcp.bootloader import Bootloader, Grub2Format, MenuEntry
 from xcp.compat import open_with_codec_handling
 
 
@@ -29,6 +29,93 @@ def test_no_multiboot(self):
         # A module2 line without a multiboot2 line is an error
         with self.assertRaises(RuntimeError):
             Bootloader.readGrub2("tests/data/grub-no-multiboot.cfg")
+
+
+class TestMenuEntry(unittest.TestCase):
+    def setUp(self):
+        self.tmpdir = mkdtemp(prefix="testbl")
+        self.fn = os.path.join(self.tmpdir, 'grub.cfg')
+        self.bl = Bootloader('grub2', self.fn)
+
+    def tearDown(self):
+        shutil.rmtree(self.tmpdir)
+
+    def test_new_multiboot(self):
+        # No format specified, default to multiboot2
+        e = MenuEntry(hypervisor='xen.efi', hypervisor_args='xarg1 xarg2',
+                      kernel='vmlinuz', kernel_args='karg1 karg2',
+                      initrd='initrd.img', title='xe')
+        self.bl.append('xe', e)
+
+        e = MenuEntry(hypervisor='xen.efi', hypervisor_args='xarg1 xarg2',
+                      kernel='vmlinuz', kernel_args='karg1 karg2',
+                      initrd='initrd.img', title='xe-serial')
+        e.entry_format = Grub2Format.MULTIBOOT2
+        self.bl.append('xe-serial', e)
+
+        self.bl.commit()
+
+        with open_with_codec_handling(self.fn, 'r') as f:
+            content = f.read()
+
+        self.assertEqual(content, '''menuentry 'xe' {
+	multiboot2 xen.efi xarg1 xarg2
+	module2 vmlinuz karg1 karg2
+	module2 initrd.img
+}
+menuentry 'xe-serial' {
+	multiboot2 xen.efi xarg1 xarg2
+	module2 vmlinuz karg1 karg2
+	module2 initrd.img
+}
+''')
+
+    def test_new_xen_boot(self):
+        e = MenuEntry(hypervisor='xen.efi', hypervisor_args='xarg1 xarg2',
+                      kernel='vmlinuz', kernel_args='karg1 karg2',
+                      initrd='initrd.img', title='xe')
+        e.entry_format = Grub2Format.XEN_BOOT
+        self.bl.append('xe', e)
+        self.bl.commit()
+
+        with open_with_codec_handling(self.fn, 'r') as f:
+            content = f.read()
+
+        self.assertEqual(content, '''menuentry 'xe' {
+	xen_hypervisor xen.efi xarg1 xarg2
+	xen_module vmlinuz karg1 karg2
+	xen_module initrd.img
+}
+''')
+
+    def test_new_linux(self):
+        e = MenuEntry(hypervisor='', hypervisor_args='',
+                      kernel='vmlinuz', kernel_args='karg1 karg2',
+                      initrd='initrd.img', title='linux')
+        self.bl.append('linux', e)
+        self.bl.commit()
+
+        e = MenuEntry(hypervisor='', hypervisor_args='',
+                      kernel='vmlinuz2', kernel_args='karg3 karg4',
+                      initrd='initrd2.img', title='linux2')
+        e.entry_format = Grub2Format.LINUX
+        self.bl.append('linux2', e)
+        self.bl.commit()
+
+        with open_with_codec_handling(self.fn, 'r') as f:
+            content = f.read()
+
+        self.assertEqual(content, '''menuentry 'linux' {
+	linux vmlinuz karg1 karg2
+	initrd initrd.img
+}
+menuentry 'linux2' {
+	linux vmlinuz2 karg3 karg4
+	initrd initrd2.img
+}
+''')
+
+
 class TestLinuxBootloader(unittest.TestCase):
     def setUp(self):
         self.tmpdir = mkdtemp(prefix="testbl")

xcp/bootloader.py

@@ -24,6 +24,7 @@
 from __future__ import division, print_function
 
 import copy
+from enum import Enum
 import os
 import os.path
 import re
@@ -42,6 +43,11 @@
 
 COUNTER = 0
 
+class Grub2Format(Enum):
+    MULTIBOOT2 = 0
+    LINUX = 1
+    XEN_BOOT = 2
+
 class MenuEntry(object):
     # pylint: disable=too-many-positional-arguments
     def __init__(self, hypervisor, hypervisor_args, kernel, kernel_args,
@@ -55,6 +61,7 @@ def __init__(self, hypervisor, hypervisor_args, kernel, kernel_args,
         self.initrd = initrd
         self.title = title
         self.root = root
+        self.entry_format = None
 
     def getHypervisorArgs(self):
         return re.findall(r'\S[^ "]*(?:"[^"]*")?\S*', self.hypervisor_args)
@@ -117,6 +124,7 @@ def readGrub2(cls, src_file):
         menu_entry_contents = []  # type: list[str]
         boilerplate = []  # type: list[str]
         boilerplates = []  # type: list[list[str]]
+        entry_format = Grub2Format.MULTIBOOT2
 
         def create_label(title):
             global COUNTER
@@ -193,14 +201,25 @@ def parse_boot_entry(line):
                 elif title:
                     if l.startswith("multiboot2"):
                         hypervisor, hypervisor_args = parse_boot_entry(l)
+                    elif l.startswith("xen_hypervisor"):
+                        entry_format = Grub2Format.XEN_BOOT
+                        hypervisor, hypervisor_args = parse_boot_entry(l)
                     elif l.startswith("module2"):
                         if not hypervisor:
                             raise RuntimeError("Need a multiboot2 kernel")
                         if kernel:
                             initrd = l.split(None, 1)[1]
                         else:
                             kernel, kernel_args = parse_boot_entry(l)
+                    elif l.startswith("xen_module"):
+                        if not hypervisor:
+                            raise RuntimeError("Need a hypervisor")
+                        if kernel:
+                            initrd = l.split(None, 1)[1]
+                        else:
+                            kernel, kernel_args = parse_boot_entry(l)
                     elif l.startswith("linux"):
+                        entry_format = Grub2Format.LINUX
                         kernel, kernel_args = parse_boot_entry(l)
                     elif l.startswith("initrd"):
                         if not kernel:
@@ -219,6 +238,7 @@ def parse_boot_entry(line):
                                                 root = root)
                         menu[label].extra = menu_entry_extra
                         menu[label].contents = menu_entry_contents
+                        menu[label].entry_format = entry_format
 
                         title = None
                         hypervisor = None
@@ -229,6 +249,7 @@ def parse_boot_entry(line):
                         root = None
                         menu_entry_extra = None
                         menu_entry_contents = []
+                        entry_format = Grub2Format.MULTIBOOT2
 
                     else:
                         menu_entry_contents.append(line.rstrip())
@@ -307,17 +328,27 @@ def writeGrub2(self, dst_file = None):
             if m.root:
                 print("\tsearch --label --set root %s" % m.root, file=fh)
 
-            if m.hypervisor:
+            if ((m.entry_format is None and m.hypervisor) or
+                    m.entry_format == Grub2Format.MULTIBOOT2):
                 print("\tmultiboot2 %s %s" % (m.hypervisor, m.hypervisor_args), file=fh)
                 if m.kernel:
                     print("\tmodule2 %s %s" % (m.kernel, m.kernel_args), file=fh)
                 if m.initrd:
                     print("\tmodule2 %s" % m.initrd, file=fh)
-            else:
-                if m.kernel:
-                    print("\tlinux %s %s" % (m.kernel, m.kernel_args), file=fh)
+            elif ((m.entry_format is None and not m.hypervisor) or
+                    m.entry_format == Grub2Format.LINUX):
+                print("\tlinux %s %s" % (m.kernel, m.kernel_args), file=fh)
                 if m.initrd:
                     print("\tinitrd %s" % m.initrd, file=fh)
+            elif m.entry_format == Grub2Format.XEN_BOOT:
+                print("\txen_hypervisor %s %s" % (m.hypervisor, m.hypervisor_args), file=fh)
+                if m.kernel:
+                    print("\txen_module %s %s" % (m.kernel, m.kernel_args), file=fh)
+                if m.initrd:
+                    print("\txen_module %s" % m.initrd, file=fh)
+            else:
+                raise AssertionError("Unreachable")
+
             print("}", file=fh)
         if not hasattr(dst_file, 'name'):
             fh.close()