#!/bin/bash
# Need bash because we use nullglob, extglob
#
# list-records
#
# Print, one per line, names of non-empty files in the current directory
# that match the shell glob patterns in /etc/resolvconf/interface-order

set -e

# Stores arguments (minus duplicates) in RSLT, separated by newlines
# Doesn't work properly if an argument itself contain whitespace
uniquify()
{
	RSLT=""
	while [ "$1" ] ; do
		for E in $RSLT ; do
			[ "$1" = "$E" ] && { shift ; continue 2 ; }
		done
		RSLT="${RSLT:+$RSLT
}$1"
		shift
	done
}

### Compile ordered list of resolv.conf-type files ###
PATTERNS="lo.inet* lo.dnsmasq lo.pdnsd lo.!(pdns|pdns-recursor) lo tun* tap* hso* em+([0-9])?(_+([0-9]))* p+([0-9])p+([0-9])?(_+([0-9]))* eth* ath* wlan* ppp* *"
if [ -r /etc/resolvconf/interface-order ] ; then
	PATTERNS="$(sed -e '
		s/^[[:space:]]\+//
		s/[[:space:]].*//
		s/#.*//
		/\//d
		/^~/d
		/^\./d
		/^$/d
		' /etc/resolvconf/interface-order)"
fi

shopt -s nullglob extglob
# The nullglob option isn't essential since the test -s below will eliminate
# any unexpanded patterns.  The extglob option makes the glob language of
# interface-order patterns as powerful as regexps.

# Pathname expansion occurs on the following line resulting, in general,
# in multiple instances of filenames; duplicates must be removed.
uniquify $PATTERNS
for FLNM in $RSLT ; do
	# Only list records of non-zero size
	[ -s "$FLNM" ] && echo "$FLNM"
done
exit 0