From 7532c5379d02fb012fa42190424a46bdb033efcc Mon Sep 17 00:00:00 2001
From: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Date: Sun, 19 Apr 2015 12:09:32 +0300
Subject: [PATCH] ddclient: Force line buffering on stdout

Status messages of ddclient go to stdout, which is block buffered by
default, so most of its output won't appear in the journal until it is
exiting:

-- Reboot --
Apr 19 11:31:04 xen systemd[1]: Starting Dynamic DNS Client...
Apr 19 11:31:04 xen systemd[1]: Started Dynamic DNS Client.
Apr 19 11:31:53 xen systemd[1]: Stopping Dynamic DNS Client...
Apr 19 11:31:53 xen ddclient[530]: === opt ====
Apr 19 11:31:53 xen ddclient[530]: opt{cache}                           : <undefined>
Apr 19 11:31:53 xen ddclient[530]: opt{cmd}                             : <undefined>
...

Fix this by adding a patch to set line buffering on stdout.
---
 .../ddclient-line-buffer-stdout.patch         | 20 +++++++++++++++++++
 pkgs/tools/networking/ddclient/default.nix    |  2 +-
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 pkgs/tools/networking/ddclient/ddclient-line-buffer-stdout.patch

diff --git a/pkgs/tools/networking/ddclient/ddclient-line-buffer-stdout.patch b/pkgs/tools/networking/ddclient/ddclient-line-buffer-stdout.patch
new file mode 100644
index 000000000000..d1ef9e024d2a
--- /dev/null
+++ b/pkgs/tools/networking/ddclient/ddclient-line-buffer-stdout.patch
@@ -0,0 +1,20 @@
+diff -u ddclient-3.8.1/ddclient ddclient-3.8.1.patched/ddclient
+--- ddclient-3.8.1/ddclient	2011-07-11 23:04:21.000000000 +0200
++++ ddclient-3.8.1.patched/ddclient	2012-11-08 11:52:31.930647236 +0100
+@@ -19,6 +19,7 @@ use strict;
+ use Getopt::Long;
+ use Sys::Hostname;
+ use IO::Socket;
++use IO::Handle qw( );
+ 
+ my ($VERSION) = q$Revision: 157 $ =~ /(\d+)/;
+ 
+@@ -675,7 +676,7 @@ $SIG{'TERM'}   = sub { $caught_term = 1; };
+ $SIG{'KILL'}   = sub { $caught_kill = 1; };
+ # don't fork() if foreground or force is on
+ if (opt('foreground') || opt('force')) {
+-    ;
++    STDOUT->autoflush(1);
+ } elsif (opt('daemon')) {
+     $SIG{'CHLD'}   = 'IGNORE';
+     my $pid = fork;
diff --git a/pkgs/tools/networking/ddclient/default.nix b/pkgs/tools/networking/ddclient/default.nix
index fdc5e145c4db..41688d843513 100644
--- a/pkgs/tools/networking/ddclient/default.nix
+++ b/pkgs/tools/networking/ddclient/default.nix
@@ -10,7 +10,7 @@ buildPerlPackage {
 
   buildInputs = [ perlPackages.IOSocketSSL perlPackages.DigestSHA1 ];
 
-  patches = [ ./ddclient-foreground.patch ];
+  patches = [ ./ddclient-foreground.patch ./ddclient-line-buffer-stdout.patch ];
 
   # Use iproute2 instead of ifconfig
   preConfigure = ''