From 2c20ee2f8a2122989d13a5477ac5cc83eeb186f3 Mon Sep 17 00:00:00 2001
From: Justin Cormack <justin.cormack@docker.com>
Date: Fri, 28 Jul 2017 13:04:14 +0100
Subject: [PATCH] Use a tmpfs for /var

Previously we were cheating and remounting /var `rw` but this does not
work if the filesystem is really read only. Nount a tmpfs, which may
be overmounted later by a persistent filesystem.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>
---
 pkg/init/bin/rc.init | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/pkg/init/bin/rc.init b/pkg/init/bin/rc.init
index 1601b6a7a..27ff9f9ad 100755
--- a/pkg/init/bin/rc.init
+++ b/pkg/init/bin/rc.init
@@ -1,11 +1,18 @@
 #!/bin/sh
 
-# mount filesystems
+# mount proc filesystem
 mount -n -t proc proc /proc -o nodev,nosuid,noexec,relatime
 
+# remount rootfs as readonly
+mount -o remount,ro /
+
+# mount tmpfs for /tmp and /run
 mount -n -t tmpfs tmpfs /run -o nodev,nosuid,noexec,relatime,size=10%,mode=755
 mount -n -t tmpfs tmpfs /tmp -o nodev,nosuid,noexec,relatime,size=10%,mode=1777
 
+# mount tmpfs for /var. This may be overmounted with a persistent filesystem later
+mount -n -t tmpfs tmpfs /var -o nodev,nosuid,noexec,relatime,size=50%,mode=755
+
 # mount devfs
 mount -n -t devtmpfs dev /dev -o nosuid,noexec,relatime,size=10m,nr_inodes=248418,mode=755
 # devices
@@ -101,14 +108,6 @@ ip link set lo up
 # for containerizing dhcpcd and other containers that need writable /etc/resolv.conf
 [ -L /etc/resolv.conf ] && mkdir -p $(dirname $(readlink -n /etc/resolv.conf)) && touch /etc/resolv.conf
 
-# remount rootfs as readonly
-mount -o remount,ro /
-
-# make /var writeable and shared
-mount -o bind /var /var
-mount -o remount,rw,nodev,nosuid,noexec,relatime /var /var
-mount --make-rshared /var
-
 # make / rshared
 mount --make-rshared /