checkpoint: ignore ipv6 if CRIU_NOIPV6 is set

Janky executes tests in a docker container and there it is impossible
to load kernel modules which are required to dump ipv6 sockets.

Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

Author: avagin

Dockerfile

@@ -41,9 +41,11 @@ RUN cd /tmp \
 
 # install criu
 ENV CRIU_VERSION 2.12
+COPY tests/hacks/0001-criu-allow-to-ignore-ipv6-if-CRIU_NOIPV6-is-set.patch /tmp/
 RUN mkdir -p /usr/src/criu \
     && curl -sSL https://github.com/xemul/criu/archive/v${CRIU_VERSION}.tar.gz | tar -v -C /usr/src/criu/ -xz --strip-components=1 \
     && cd /usr/src/criu \
+    && cat /tmp/0001-criu-allow-to-ignore-ipv6-if-CRIU_NOIPV6-is-set.patch | patch -p1 \
     && make install-criu \
     && rm -rf /usr/src/criu
 
@@ -56,6 +58,8 @@ RUN mkdir -p /go/src/github.com/mvdan \
     && go install ./cmd/shfmt \
     && rm -rf /go/src/github.com/mvdan
 
+ENV CRIU_NOIPV6 1
+
 # setup a playground for us to spawn containers in
 ENV ROOTFS /busybox
 RUN mkdir -p ${ROOTFS} \

tests/hacks/0001-criu-allow-to-ignore-ipv6-if-CRIU_NOIPV6-is-set.patch

@@ -0,0 +1,26 @@
+From 8a9b1d0e6929d296254a8892e553621d76810e87 Mon Sep 17 00:00:00 2001
+From: Andrei Vagin <avagin@openvz.org>
+Date: Thu, 2 Mar 2017 14:44:18 -0800
+Subject: [PATCH] criu: allow to ignore ipv6 if CRIU_NOIPV6 is set
+
+Signed-off-by: Andrei Vagin <avagin@openvz.org>
+---
+ criu/kerndat.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/criu/kerndat.c b/criu/kerndat.c
+index 162ac28..216afe0 100644
+--- a/criu/kerndat.c
++++ b/criu/kerndat.c
+@@ -433,6 +433,8 @@ out:
+ 
+ static int get_ipv6()
+ {
++	if (getenv("CRIU_NOIPV6"))
++		return 0;
+ 	if (access("/proc/sys/net/ipv6", F_OK) < 0) {
+ 		if (errno == ENOENT) {
+ 			pr_debug("ipv6 is disabled\n");
+-- 
+2.9.3
+