Simplify DHCP lease file parer after switch to dhcpleased

dhcpleased(8)'s lease files are much simpler than dhclient.leases(5):
- exactly one lease per file (not many)
- only option lines (not statement, declaration, etc.)
- every option/value is separated by a single ": " (no optional leading
  "option ")
- values are not quoted or escaped (like dhclient does)

lease_value() is hard to read, mostly because it strips optional double
quotes around option values as was required with dhclient.

dhclient VIS_ALL's values if they contain backticks, backslashes and
other characters, otherwise it VIS_SAFE's (and optionally quotes them).

dhcpleased VIS_SAFE's all value strings equally.

All install.sub users of lease_value() quote its output so they should
be safe without any special unescaping as previously done.

OK florian

1 files changed, 8 insertions, 9 deletions

diff --git a/distrib/miniroot/install.sub b/distrib/miniroot/install.sub
index 999c0b095aa..fb95222fef5 100644
--- a/distrib/miniroot/install.sub
+++ b/distrib/miniroot/install.sub
@@ -1,5 +1,5 @@
 #!/bin/ksh
-#	$OpenBSD: install.sub,v 1.1168 2021/07/18 15:18:49 deraadt Exp $
+#	$OpenBSD: install.sub,v 1.1169 2021/07/20 11:20:09 kn Exp $
 #
 # Copyright (c) 1997-2015 Todd Miller, Theo de Raadt, Ken Westerback
 # Copyright (c) 2015, Robert Peichaer <rpe@openbsd.org>
@@ -244,21 +244,20 @@ prep_root_mail() {
 __EOT
 }
 
-# Examine the contents of the DHCP lease file $1 for a line containing the
-# field provided as parameters and return the value of the first field found.
+# Examine the contents of the dhcpleased lease file $1 for a line containing the
+# field(s) provided as parameters and return the value of the first field found.
 #
-# Note that strings are unescaped but not unvis()'d.
+# Note that value strings are VIS_SAFE'd.
 lease_value() {
-	local _lf=$1 _o
+	local _lf=$1 _o _opt _val
 
 	[[ -s $_lf ]] || return
 	shift
 
 	for _o; do
-		sed -E \
-			-e '/^'"$_o"': (.*)$/!d;s//\1/' \
-			-e '/^"(.*)"$/{s//\1/;s/\\(.)/\1/g;};q' "$_lf" \
-			| grep ^ && return
+		while read -r _opt _val; do
+			[[ $_opt == ${_o}: ]] && echo "$_val" && return
+		done < "$_lf"
 	done
 }