base-files: add option to make /var persistent

In OpenWrt, /var is symlinked to /tmp by default. This is done to reduce
the amount of writes to the flash chip, which often have not the
greatest durability. As a result, things like DHCP or UPnP lease files,
are not persistent across reboots.

Since OpenWrt can run on devices with more durable storage, it makes
sense to have an option for a persistent /var. Add an option to make
/var persistent. When enabled, /var will no longer be symlinked to /tmp,
but /var/run will be symlink to /tmp/run, as it should contains only
files that should not be kept during reboot. The option is off by
default, to maintain the current behaviour.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>

diff --git a/config/Config-images.in b/config/Config-images.in
index 4a7f08824bd7b9c0ced50fa10282c8575cf5286a..92720fb84d506650267228ac631b474525aa93cb 100644 (file)
--- a/config/Config-images.in
+++ b/config/Config-images.in
@@ -303,4 +303,12 @@ menu "Target Images"
                  it will be mounted by PARTUUID which makes the kernel find the
                  appropriate disk automatically.
 
+       config TARGET_ROOTFS_PERSIST_VAR
+               bool "Make /var persistent"
+               default n
+               help
+                 Do not symlink /var to /tmp, so that its content will persist
+                 across reboots. When enabled, /var/run will still be linked
+                 to /tmp/run.
+
 endmenu

diff --git a/package/base-files/Makefile b/package/base-files/Makefile
index d67f551b9c5513181b8e2a9db8d83830b59c61fb..6da3df2b4ea775bb420d00c8955818c5a393360b 100644 (file)
--- a/package/base-files/Makefile
+++ b/package/base-files/Makefile
@@ -181,8 +181,13 @@ define Package/base-files/install
        mkdir -p $(1)/www
        mkdir -p $(1)/root
        $(LN) /proc/mounts $(1)/etc/mtab
+ifeq ($(CONFIG_TARGET_ROOTFS_PERSIST_VAR),n)
        rm -f $(1)/var
        $(LN) tmp $(1)/var
+else
+       mkdir -p $(1)/var
+       $(LN) /tmp/run $(1)/var/run
+endif
        mkdir -p $(1)/etc
        $(LN) /tmp/resolv.conf /tmp/TZ /tmp/localtime $(1)/etc/