config

declare -ri max_file_size=200*1048576

declare -r base_dir="/etc/preloader"

declare -ra exclude_ext=(
	avi mpg mpeg mp? m?v m?a og? flac vob mkv wav riff mov h26?
	nef raw
	gz bz2 xz 7z lzma tar zip rar cab
	lock lck log
	'~*'
)

declare -ra exclude=(
	'^/(boot|proc|sys|dev|run|tmp)/'
	'incomplete|\.!|~'
	'/Cache'
	'\.tmp$'
	'~$'
	'^\./'
	'/etc/(passwd|shadow|group)'
	'xauth'
	'/(lock|LOCK)$'
)

################################################################################

if [ -e "${base_dir}/config" ]; then
	source "${base_dir}/config"
fi

declare list_dir="${base_dir}/lists"

if ! [ -e "${base_dir}" ]; then
	sudo mkdir -p "${base_dir}"
	sudo mkdir -p "${list_dir}"
fi

# Security problem: any user could add a massive load of data to the preload
# list, causing the preloader to trigger an OOM.  We could add a
# "max_payload_size" config var to get around this.
if ! [ -w "${list_dir}" -a -r "${list_dir}" -a -x "${list_dir}" ]; then
	sudo chmod -R 777 "${list_dir}"
fi

function join_array {
	# Delim cannot contain '%'
	local delim="$1"
	shift
	if (( $# == 0 )); then
		return
	fi
	printf -- "%s" "$1"
	shift
	printf -- "${delim}%s" "$@"
}

function get_filter_rx {
	local rx=''
	rx+="$(join_array '|' "${exclude_ext[@]}" | sed -e 's/?/./g;s/\*/.*/g'; printf '$')"
	rx+="|$(join_array '|' "${exclude[@]}")"
	printf -- "%s" "${rx}" | sed -e 's/\//\\\//g'
}

declare -r exclude_rx="$(get_filter_rx)"

function glue_prog {
cat <<EOF
	use strict;
	use warnings;
	use feature qw(say);
	my \$rx = qr/${exclude_rx}/;
EOF
cat <<'EOF'
	while (<>) {
		if (/open\(\s*"([^"]+)"(?:\s*,\s*([\w|]+)(?:\s*,\s*(\d+)?)?)\s*\)\s*=\s*(-?\d+)/) {
			my $path = $1;
			my $mode = $2 // "<unspecified>";
			my $permission = $3 // "<unspecified>";
			my $res = $4;
			say $path if ($res >= 1 and $path !~ $rx);
		}
	}
EOF
}

function is_excluded {
	echo "$@" | perl <(
cat <<EOF
	use strict;
	use warnings;
	my \$rx = qr/${exclude_rx}/;
EOF
cat <<'EOF'
	while (<>) {
		exit(0) if ($_ =~ $rx);
	}
	exit(1);
EOF
	)
}