dnsmasq: pass environment variables to hotplug

dnsmasq passes a limited amount of information via DHCP script arguments. Much
more information is available through environment variables starting with
DNSMASQ_, such as DNSMASQ_INTERFACE. However, when the dhcp-script builds its
JSON environment and passes it to hotplug, all of this information is discarded
since it is not copied to the JSON environment.

Personally, I have a custom-made set of DDNS scripts and rely on environment
variables such as DNSMASQ_INTERFACE in order to determine which DNS zones
to update. So, not being able to access these variables was detrimental to me.
I patched in a quick copy of all DNSMASQ_ variables to the JSON environment
so that they can be used in hotplug scripts. In order to do so I also copied
/usr/bin/env into dnsmasq's chroot jail.

Signed-off-by: Chuck R <github@chuck.cloud>
Link: https://github.com/openwrt/openwrt/pull/16354
Signed-off-by: John Crispin <john@phrozen.org>

diff --git a/package/network/services/dnsmasq/files/dhcp-script.sh b/package/network/services/dnsmasq/files/dhcp-script.sh
index 470097bf6bd6fd049eb2706572ea79f34c171217..f0c8b5090203d52aa86a8ab8bea792b1567a79df 100755 (executable)
--- a/package/network/services/dnsmasq/files/dhcp-script.sh
+++ b/package/network/services/dnsmasq/files/dhcp-script.sh
@@ -8,6 +8,15 @@ json_init
 json_add_array env
 hotplugobj=""
 
+oldIFS=$IFS
+IFS=$'\n'
+for var in $(env); do
+       if [ "${var}" != "${var#DNSMASQ_}" ]; then
+               json_add_string "" "${var%%=*}=${var#*=}"
+       fi
+done
+IFS=$oldIFS
+
 case "$1" in
        add | del | old | arp-add | arp-del)
                json_add_string "" "MACADDR=$2"

diff --git a/package/network/services/dnsmasq/files/dnsmasq.init b/package/network/services/dnsmasq/files/dnsmasq.init
index b864ea90699f484ad124a1f1107f7ac10b2fb770..2e07e13d36726ad1342ab2478777fcf0a84986ce 100755 (executable)
--- a/package/network/services/dnsmasq/files/dnsmasq.init
+++ b/package/network/services/dnsmasq/files/dnsmasq.init
@@ -20,7 +20,7 @@ BASEDHCPSTAMPFILE="/var/run/dnsmasq"
 DHCPBOGUSHOSTNAMEFILE="/usr/share/dnsmasq/dhcpbogushostname.conf"
 RFC6761FILE="/usr/share/dnsmasq/rfc6761.conf"
 DHCPSCRIPT="/usr/lib/dnsmasq/dhcp-script.sh"
-DHCPSCRIPT_DEPENDS="/usr/share/libubox/jshn.sh /usr/bin/jshn /bin/ubus"
+DHCPSCRIPT_DEPENDS="/usr/share/libubox/jshn.sh /usr/bin/jshn /bin/ubus /usr/bin/env"
 
 DNSMASQ_DHCP_VER=4