From 16a29e1cd80caf1c63430038e653be3fa4258e0a Mon Sep 17 00:00:00 2001
From: Michael Prokop <mika@grml.org>
Date: Sat, 28 May 2011 17:54:14 +0200
Subject: [PATCH] Rework resolv.conf handling, error out on wrong symlinks.
 [Closes: issue984]

Make sure the resolv.conf setup is correct and error out
accordingly otherwise, while at it make sure the code
is the same in instsoft.GRMLBASE and 96-apt-listbugs.

Thanks to Andreas Korsten for reporting.
---
 etc/grml/fai/config/hooks/instsoft.GRMLBASE          | 19 ++++++++++++++++---
 etc/grml/fai/config/scripts/GRMLBASE/96-apt-listbugs | 19 ++++++++++++++++---
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/etc/grml/fai/config/hooks/instsoft.GRMLBASE b/etc/grml/fai/config/hooks/instsoft.GRMLBASE
index c8150be..cf8c3be 100755
--- a/etc/grml/fai/config/hooks/instsoft.GRMLBASE
+++ b/etc/grml/fai/config/hooks/instsoft.GRMLBASE
@@ -21,11 +21,24 @@ if [ "$FAI_ACTION" = "softupdate" ] ; then
    echo "Action $FAI_ACTION of FAI (hooks/instsoft.GRMLBASE) via grml-live running"
 
    if [ -r /etc/resolv.conf ] ; then
-      if [ -r $target/etc/resolvconf/run/resolv.conf ] ; then
+     if [ -d $target/etc/resolvconf/run ] ; then # resolvconf
+       # sanity check to avoid "input file is output file",
+       # see http://bts.grml.org/grml/issue984
+       if ! [ -L $target/etc/resolvconf/run/resolv.conf ] ; then
          cat /etc/resolv.conf >> $target/etc/resolvconf/run/resolv.conf
-      else
+       else
+         echo "Error: /etc/resolvconf/run/resolv.conf in chroot should not be a symlink." >&2
+         echo "       Looks like something is wrong, please fix manually." >&2
+         exit 1
+       fi
+     else # no resolvconf installed in chroot
+       if ! [ -L $target/etc/resolv.conf ] ; then
          cat /etc/resolv.conf >> $target/etc/resolv.conf
-      fi
+       else
+         echo "Error: /etc/resolv.conf in chroot should not be a symlink (resolvconf not installed)." >&2
+         exit 1
+       fi
+     fi
    fi
 
    if [ -r $target/etc/policy-rc.d.conf ] ; then
diff --git a/etc/grml/fai/config/scripts/GRMLBASE/96-apt-listbugs b/etc/grml/fai/config/scripts/GRMLBASE/96-apt-listbugs
index f1083d3..bbe6117 100755
--- a/etc/grml/fai/config/scripts/GRMLBASE/96-apt-listbugs
+++ b/etc/grml/fai/config/scripts/GRMLBASE/96-apt-listbugs
@@ -22,11 +22,24 @@ if ifclass RELEASE ; then
   [ -n "$HOSTNAME" ] || HOSTNAME=grml
 
   if [ -r /etc/resolv.conf ] ; then
-     if [ -d $target/etc/resolvconf/run ] ; then
+    if [ -d $target/etc/resolvconf/run ] ; then # resolvconf
+      # sanity check to avoid "input file is output file",
+      # see http://bts.grml.org/grml/issue984
+      if ! [ -L $target/etc/resolvconf/run/resolv.conf ] ; then
         cat /etc/resolv.conf >> $target/etc/resolvconf/run/resolv.conf
-     elif [ ! -L $target/etc/resolv.conf ] ; then
+      else
+        echo "Error: /etc/resolvconf/run/resolv.conf in chroot should not be a symlink." >&2
+        echo "       Looks like something is wrong, please fix manually." >&2
+        exit 1
+      fi
+    else # no resolvconf installed in chroot
+      if ! [ -L $target/etc/resolv.conf ] ; then
         cat /etc/resolv.conf >> $target/etc/resolv.conf
-     fi
+      else
+        echo "Error: /etc/resolv.conf in chroot should not be a symlink (resolvconf not installed)." >&2
+        exit 1
+      fi
+    fi
   fi
 
   if [ -x $target/usr/sbin/apt-listbugs -a -x $target/usr/bin/apt-show-source ] && \
-- 
2.1.4