Bug#701647: ltsp-client-core: fails to write /etc/resolv.conf if package resolvconf is installed

["Wolfgang Schweer" <w.schweer@gmx.de>]

Package: ltsp-client-core
Version: 5.4.2-5
Severity: normal
Tags: upstream patch

Hi,

while testing ltsp setup for Debian Edu running fat clients I noticed, 
that /etc/resolv.conf was't written like expected (by 10-resolv-conf).
This seems to be caused by $resolv not beeing writable.

Using the /etc/network/interface information worked for me. The script 
has then to be run later, so renamed to 60-resolv-conf.

Find the script attached; here's the diff:

--- 10-resolv-conf	2012-06-27 00:00:00.000000000 +0200
+++ 60-resolv-conf	2013-02-21 20:05:04.000000000 +0100
@@ -27,24 +27,26 @@
 
 # Apply the dns info that was received from dhcp or from lts.conf
 if [ -n "$DNS_SERVER" ] || [ -n "$SEARCH_DOMAIN" ]; then
-    # Deal with resolvconf
+    # Deal with resolvconf, use writable interface file.
     if [ -x /sbin/resolvconf ] && ( [ -L /etc/resolv.conf ] || [ -e /var/lib/resolvconf/convert ] ); then
-        mkdir -p /run/resolvconf/interface/
-        resolv_method=resolvconf
-        resolv=/run/resolvconf/interface/LTSP
-    else
-        resolv_method=static
-        resolv=/etc/resolv.conf
-    fi
-
-    # Check if $resolv is writable
-    if echo '# Generated by ltsp' 2>/dev/null > "$resolv"; then
         if [ -n "$SEARCH_DOMAIN" ]; then
-            echo "search $SEARCH_DOMAIN" >> "$resolv"
+            echo "dns-search $SEARCH_DOMAIN" >> /etc/network/interfaces
         fi
         for n in $DNS_SERVER; do
+            echo "dns-nameservers $n" >> /etc/network/interfaces
+        done
+    else
+	# Static case
+        resolv=/etc/resolv.conf
+	# Check if $resolv is writable
+	if echo '# Generated by ltsp' 2>/dev/null > "$resolv"; then
+    	    if [ -n "$SEARCH_DOMAIN" ]; then
+        	echo "search $SEARCH_DOMAIN" >> "$resolv"
+    	    fi
+        for n in $DNS_SERVER; do
             echo "nameserver $n" >> "$resolv"
         done
+        fi
     fi
 fi
 true

Additionally Debian Edu needs working DNS for KERBEROS.  This can be 
done by modifying /etc/nsswitch.conf without touching /etc/hosts.  I 
wonder if something similar would make sense to be integrated into 
ltsp-client-core.

Find the script 70-edu-nsswitch attached.
This would IMHO close bug #613988.

Wolfgang

# set to defaults from DHCP if not specified in lts.conf
if [ -z "$DNS_SERVER" ]; then
    for dns in $IPV4DNS0 $IPV4DNS1 ; do
        # ignore nameserver of 0.0.0.0, which ipconfig may return if both
        # nameservers aren't specified.
        if [ "$dns" != "0.0.0.0" ]; then
            DNS_SERVER="$DNS_SERVER $dns"
        fi
    done
fi

# If no DNS_SERVER was defined in lts.conf or in DHCP (e.g. IPAPPEND=3),
# check the LTSP server, gateway, and Google Public DNS.
if [ -z "$DNS_SERVER" ] && [ -x /usr/bin/dig ]; then
    gateway=$(LANG=C ip route | sed -n 's/default via \([0-9.]*\).*/\1/p')
    for dns in $SERVER $gateway 8.8.8.8; do
        if dig +time=1 +tries=1 +short "@$dns" localhost >/dev/null 2>&1; then
            DNS_SERVER="$dns"
            break
        fi
    done
fi

if [ -z "$SEARCH_DOMAIN" ] && [ -n "$DNSDOMAIN" ]; then
    SEARCH_DOMAIN="$DNSDOMAIN"
fi

# Apply the dns info that was received from dhcp or from lts.conf
if [ -n "$DNS_SERVER" ] || [ -n "$SEARCH_DOMAIN" ]; then
    # Deal with resolvconf, use writable interface file.
    if [ -x /sbin/resolvconf ] && ( [ -L /etc/resolv.conf ] || [ -e /var/lib/resolvconf/convert ] ); then
        if [ -n "$SEARCH_DOMAIN" ]; then
            echo "dns-search $SEARCH_DOMAIN" >> /etc/network/interfaces
        fi
        for n in $DNS_SERVER; do
            echo "dns-nameservers $n" >> /etc/network/interfaces
        done
    else
	# Static case
        resolv=/etc/resolv.conf
	# Check if $resolv is writable
	if echo '# Generated by ltsp' 2>/dev/null > "$resolv"; then
    	    if [ -n "$SEARCH_DOMAIN" ]; then
        	echo "search $SEARCH_DOMAIN" >> "$resolv"
    	    fi
        for n in $DNS_SERVER; do
            echo "nameserver $n" >> "$resolv"
        done
        fi
    fi
fi
true

# For Debian Edu diskless workstations (i.e. ltsp fat clients).
# As dns service is available, modify priority to make KERBEROS work.
if boolean_is_true "$LTSP_FATCLIENT"; then
    sed -i s/compat/ldap\ compat/ /etc/nsswitch.conf
    sed -i s/files\ my/dns\ files\ my/ /etc/nsswitch.conf
    sed  -i s/netgroups:\ *files/netgroups:\ \ \ \ \ \ ldap\ files/ nsswitch.conf
fi

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