#!/bin/sh
# daede-sub - serve a converter's staged node list to the local daed only.
#
# daed (dae-wing) can only build a subscription by HTTP-fetching a link, and it
# does not read file:// like dae core. So the converter stores the base64 share
# links in /etc/daed/daede-sub-<token> and points daed's importSubscription at
# http://127.0.0.1/cgi-bin/daede-sub?t=<token>. This CGI is the read side.
#
# Locked to loopback (REMOTE_ADDR), so even though uhttpd listens on the LAN no
# remote client can pull the links. The snapshot remains available for daed's
# own refresh action and is included in daede configuration backups.

deny() { printf 'Status: 403 Forbidden\r\nContent-Type: text/plain\r\n\r\nforbidden\n'; exit 0; }

[ "$REMOTE_ADDR" = "127.0.0.1" ] || deny

# token: only [A-Za-z0-9] so the path can't escape /tmp
t=$(printf '%s' "$QUERY_STRING" | sed -n 's/^.*\bt=\([A-Za-z0-9]\{1,64\}\).*$/\1/p')
[ -n "$t" ] || deny

f="/etc/daed/daede-sub-$t"
[ -f "$f" ] || deny

printf 'Content-Type: text/plain\r\n\r\n'
cat "$f"