Add functions to add/remove /dev/null in chroots.

Sometimes we only need /dev/null, so just create that. Check we get
passed a non-empty string for the root location, to make sure we don't
accidently delete the build system's /dev/null.

1 files changed, 16 insertions, 1 deletions

diff --git a/lib/MGA/DrakISO/Utils.pm b/lib/MGA/DrakISO/Utils.pm
index f98e46d..c283d0d 100644
--- a/lib/MGA/DrakISO/Utils.pm
+++ b/lib/MGA/DrakISO/Utils.pm
@@ -33,7 +33,8 @@ use IO::Select;
 
 use Exporter;
 our @ISA = qw(Exporter);
-our @EXPORT = qw($sudo directory_usage glob__ run_ run_as_root run_in_root copy_or_link mount mount_system_fs umount_all_in_root);
+our @EXPORT = qw($sudo directory_usage glob__ run_ run_as_root run_in_root copy_or_link
+                 mk_dev_null rm_dev_null mount mount_system_fs umount_all_in_root);
 
 our $sudo = $> ? 'sudo' : '';
 
@@ -116,6 +117,20 @@ sub copy_or_link {
       or die "ERROR: couldn't link $src_file to $dst_file\n";
 }
 
+sub mk_dev_null {
+    my ($root) = @_;
+    $root or die;
+    return if -e $root . '/dev/null';
+    run_as_root('mkdir', '-p', $root . '/dev');
+    run_as_root('cp', '-a', '/dev/null', $root . '/dev');
+}
+
+sub rm_dev_null {
+    my ($root) = @_;
+    $root or die;
+    run_as_root('rm', $root . '/dev/null') if -e $root . '/dev/null';
+}
+
 sub mount {
     my ($dst, $src, @o_options) = @_;
     mkdir_p($dst);