[fstab] Write configurable options to crypttab (default: luks).

fstab.conf: Add a new "crypttabOptions" option that defaults to "luks".
            Document that for Debian and Debian-based distributions, the
            setting should be changed to "luks,keyscript=/bin/cat".

main.py: Append the options from the above setting to the end of every
         line in crypttab.

At least the "luks" option should always be there, because there may be
different encryption types. The Debian initramfs-tools also require the
Debian-specific keyscript option and will otherwise ignore the keyfile
entirely (see pull request #254).

src/modules/fstab/fstab.conf

@@ -8,3 +8,6 @@ ssdExtraMountOptions:
     xfs: discard
     swap: discard
     btrfs: discard,compress=lzo
+crypttabOptions: luks
+# For Debian and Debian-based distributions, change the above line to:
+# crypttabOptions: luks,keyscript=/bin/cat

src/modules/fstab/main.py

@@ -102,11 +102,13 @@ class FstabGenerator(object):
     :param mount_options:
     :param ssd_extra_mount_options:
     """
-    def __init__(self, partitions, root_mount_point, mount_options, ssd_extra_mount_options):
+    def __init__(self, partitions, root_mount_point, mount_options,
+                 ssd_extra_mount_options, crypttab_options):
         self.partitions = partitions
         self.root_mount_point = root_mount_point
         self.mount_options = mount_options
         self.ssd_extra_mount_options = ssd_extra_mount_options
+        self.crypttab_options = crypttab_options
         self.ssd_disks = set()
         self.root_is_ssd = False
 
@@ -156,14 +158,16 @@ class FstabGenerator(object):
             name=mapper_name,
             device="UUID=" + luks_uuid,
             password="/crypto_keyfile.bin",
+            options=self.crypttab_options,
         )
 
     def print_crypttab_line(self, dct, file=None):
         """ Prints line to '/etc/crypttab' file. """
-        line = "{:21} {:<45} {}".format(dct["name"],
-                                        dct["device"],
-                                        dct["password"],
-                                       )
+        line = "{:21} {:<45} {} {}".format(dct["name"],
+                                           dct["device"],
+                                           dct["password"],
+                                           dct["options"],
+                                          )
 
         print(line, file=file)
 
@@ -255,9 +259,11 @@ def run():
     root_mount_point = global_storage.value("rootMountPoint")
     mount_options = conf["mountOptions"]
     ssd_extra_mount_options = conf.get("ssdExtraMountOptions", {})
+    crypttab_options = conf.get("crypttabOptions", "luks")
     generator = FstabGenerator(partitions,
                                root_mount_point,
                                mount_options,
-                               ssd_extra_mount_options)
+                               ssd_extra_mount_options,
+                               crypttab_options)
 
     return generator.run()