[PATCH 2/2] support resolvconf in the squashfs

[Evgeni Golov <evgeni+git@golov.de>]

From: Evgeni Golov <evgeni@grml.org>

when resolvconf is used in the squashfs, /etc/resolv.conf is a symlink
to the generated version. depending on the size of the squashfs, the
moon phase and the charge of the flux capacitor, we sometimes try to
write to /etc/resolv.conf while it still points to nirvana, as resolvconf
did not generate it yet.

instead of being racy and writing to a file which will be regenerated
anyways, let's detect resolvconf and write to its base file instead.

initial detection idea by Mika Prokop <mika@grml.org>
---
 components/9990-main.sh    | 12 +++++++++---
 components/9990-netbase.sh | 15 ++++++++++-----
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/components/9990-main.sh b/components/9990-main.sh
index 83f087f..85b8a1d 100755
--- a/components/9990-main.sh
+++ b/components/9990-main.sh
@@ -178,10 +178,16 @@ Live ()
 		fi
 	fi
 
-	if [ -f /etc/resolv.conf ] && [ ! -s ${rootmnt}/etc/resolv.conf ]
+	if [ -L /root/etc/resolv.conf ] ; then
+		# assume we have resolvconf
+		DNSFILE="${rootmnt}/etc/resolvconf/resolv.conf.d/base"
+	else
+		DNSFILE="${rootmnt}/etc/resolv.conf"
+	fi
+	if [ -f /etc/resolv.conf ] && [ ! -s ${DNSFILE} ]
 	then
-		log_begin_msg "Copying /etc/resolv.conf to ${rootmnt}/etc/resolv.conf"
-		cp -v /etc/resolv.conf ${rootmnt}/etc/resolv.conf
+		log_begin_msg "Copying /etc/resolv.conf to ${DNSFILE}"
+		cp -v /etc/resolv.conf ${DNSFILE}
 		log_end_msg
 	fi
 
diff --git a/components/9990-netbase.sh b/components/9990-netbase.sh
index af3522f..a32a47b 100755
--- a/components/9990-netbase.sh
+++ b/components/9990-netbase.sh
@@ -16,7 +16,12 @@ Netbase ()
 	log_begin_msg "Preconfiguring networking"
 
 	IFFILE="/root/etc/network/interfaces"
-	DNSFILE="/root/etc/resolv.conf"
+	if [ -L /root/etc/resolv.conf ] ; then
+		# assume we have resolvconf
+		DNSFILE="/root/etc/resolvconf/resolv.conf.d/base"
+	else
+		DNSFILE="/root/etc/resolv.conf"
+	fi
 
 	if [ "${STATICIP}" = "frommedia" ] && [ -e "${IFFILE}" ]
 	then
@@ -102,7 +107,7 @@ EOF
 			done
 		fi
 
-		if [ ! -f /root/etc/resolv.conf ] || [ -z "$(cat /root/etc/resolv.conf)" ]
+		if [ ! -f "${DNSFILE}" ] || [ -z "$(cat ${DNSFILE})" ]
 		then
 			if [ -f /netboot.config ]
 			then
@@ -112,7 +117,7 @@ EOF
 				rc_search=$(cat netboot.config | awk '/domain/ { print $3 }')
 				rc_server0="$(cat netboot.config | awk '/dns0/ { print $5 }')"
 
-cat > /root/etc/resolv.conf << EOF
+cat > $DNSFILE << EOF
 search ${rc_search}
 domain ${rc_search}
 nameserver ${rc_server0}
@@ -122,10 +127,10 @@ EOF
 
 				if [ "${rc_server1}" != "0.0.0.0" ]
 				then
-					echo "nameserver ${rc_server1}" >> /root/etc/resolv.conf
+					echo "nameserver ${rc_server1}" >> $DNSFILE
 				fi
 
-				cat /root/etc/resolv.conf >> /root/var/log/netboot.config
+				cat $DNSFILE >> /root/var/log/netboot.config
 			fi
 		fi
 	fi
-- 
1.9.1