Definition for managing Grub 0.x options.

This adds the defintion bootloader::grub0::option, which can set and
unset options in the Grub 0.x config file.  It handles both "bare"
options (e.g. 'hiddenmenu') and valued options (e.g. timeout=5).

Managing Grub 2 options seems a bit more complicated, so for now we
only implement the Grub 0.x version.

manifests/grub0/option.pp

+# Copyright © 2018   Thomas Bellman, Linköping, Sweden
+# Licensed under the GNU LGPL v3+; see the README file for more information.
+
+
+/*
+ * Set or remove an option for Grub 0.x.
+ *
+ * Parameters
+ *  - name	Grub0 option to set or remove
+ *
+ *  - ensure	One of 'present' (the default) or 'absent'.
+ *
+ *  - value	What value to set for the option.  If set to true, it will
+ *		be a value-less option, e.g. 'hiddenmenu'.
+ */
+define bootloader::grub0::option($ensure='present', $value=undef)
+{
+    $qname = regexp_quote($name)
+
+    # The Agueas Grub lens puts new options at the end of the file, after
+    # all boot alternatives ('title' options).  People probably don't
+    # expect that, and will be confused when trying to find such options.
+    # By using ensure_line, we can put them in a reasonable position.
+
+    if ($ensure == 'absent')
+    {
+	delete_lines {
+	    "bootloader::grub0::option::${name}":
+		file => '/boot/grub/grub.conf',
+		pattern => "${qname}(=.*)?";
+	}
+    }
+    elsif ($ensure != 'present')
+    {
+	fail("Bootloader::Option[${title}]: ",
+	     "Bad ensure parameter, ${ensure}")
+    }
+    elsif ($value == true)
+    {
+	ensure_line {
+	    "bootloader::grub0::option::${name}":
+		file => '/boot/grub/grub.conf',
+		line => $name,
+		pattern => "${qname}(\s*=.*)",
+		addhow => 'prepend',
+		where => '((title\s*.*$)|)$';
+	}
+    }
+    else
+    {
+	ensure_line {
+	    "bootloader::grub0::option::${name}":
+		file => '/boot/grub/grub.conf',
+		line => "${name}=${value}",
+		pattern => "${qname}(\s*=.*)",
+		addhow => 'prepend',
+		where => '((title\s*.*$)|)$';
+	}
+    }
+}