grub module: add extraInitrd option

nixos/modules/system/boot/loader/grub/install-grub.pl

@@ -49,6 +49,7 @@ my $extraPrepareConfig = get("extraPrepareConfig");
 my $extraPerEntryConfig = get("extraPerEntryConfig");
 my $extraEntries = get("extraEntries");
 my $extraEntriesBeforeNixOS = get("extraEntriesBeforeNixOS") eq "true";
+my $extraInitrd = get("extraInitrd");
 my $splashImage = get("splashImage");
 my $configurationLimit = int(get("configurationLimit"));
 my $copyKernels = get("copyKernels") eq "true";
@@ -226,6 +227,13 @@ my $grubStore;
 if ($copyKernels == 0) {
     $grubStore = GrubFs($storePath);
 }
+my $extraInitrdPath;
+if ($extraInitrd) {
+    if (! -f $extraInitrd) {
+        print STDERR "Warning: the specified extraInitrd " . $extraInitrd . " doesn't exist. Your system won't boot without it.\n";
+    }
+    $extraInitrdPath = GrubFs($extraInitrd);
+}
 
 # Generate the header.
 my $conf .= "# Automatically generated.  DO NOT EDIT THIS FILE!\n";
@@ -336,6 +344,9 @@ sub addEntry {
 
     my $kernel = copyToKernelsDir(Cwd::abs_path("$path/kernel"));
     my $initrd = copyToKernelsDir(Cwd::abs_path("$path/initrd"));
+    if ($extraInitrd) {
+        $initrd .= " " .$extraInitrdPath->path;
+    }
     my $xen = -e "$path/xen.gz" ? copyToKernelsDir(Cwd::abs_path("$path/xen.gz")) : undef;
 
     # FIXME: $confName
@@ -358,6 +369,9 @@ sub addEntry {
         if ($copyKernels == 0) {
             $conf .= $grubStore->search . "\n";
         }
+        if ($extraInitrd) {
+            $conf .= $extraInitrdPath->search . "\n";
+        }
         $conf .= "  $extraPerEntryConfig\n" if $extraPerEntryConfig;
         $conf .= "  multiboot $xen $xenParams\n" if $xen;
         $conf .= "  " . ($xen ? "module" : "linux") . " $kernel $kernelParams\n";