openwrt/package/network/services/dnsmasq/files/dhcp-script.sh
Chuck R 36f309af05 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>
2024-12-12 11:00:38 +01:00

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#!/bin/sh
[ -f "$USER_DHCPSCRIPT" ] && . "$USER_DHCPSCRIPT" "$@"
. /usr/share/libubox/jshn.sh
json_init
json_add_array env
hotplugobj=""
oldIFS=$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"
json_add_string "" "IPADDR=$3"
;;
esac
case "$1" in
add)
json_add_string "" "ACTION=add"
json_add_string "" "HOSTNAME=$4"
hotplugobj="dhcp"
;;
del)
json_add_string "" "ACTION=remove"
json_add_string "" "HOSTNAME=$4"
hotplugobj="dhcp"
;;
old)
json_add_string "" "ACTION=update"
json_add_string "" "HOSTNAME=$4"
hotplugobj="dhcp"
;;
arp-add)
json_add_string "" "ACTION=add"
hotplugobj="neigh"
;;
arp-del)
json_add_string "" "ACTION=remove"
hotplugobj="neigh"
;;
tftp)
json_add_string "" "ACTION=add"
json_add_string "" "TFTP_SIZE=$2"
json_add_string "" "TFTP_ADDR=$3"
json_add_string "" "TFTP_PATH=$4"
hotplugobj="tftp"
;;
esac
json_close_array env
[ -n "$hotplugobj" ] && ubus call hotplug.${hotplugobj} call "$(json_dump)"