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authorDavid Kaspar [Dee'Kej] <dkaspar@redhat.com>2017-10-30 17:08:42 +0100
committerDee'Kej <deekej@linuxmail.org>2017-10-31 13:11:59 +0100
commit5d6156454bf8f6dab4a5fdd7e1bf6cdc72c09456 (patch)
treec9a61b6f7fc553ada018d1bf13dd7b4a2cc3c467 /sysconfig/network-scripts/ifup-post
parent9e48c7ad6fae91a333d0b0a39cffee14a3130f2c (diff)
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ifup-post: always update nameserver & search entries in /etc/resolv.conf
This is complete rework of how we generate the /etc/resolv.conf. Fixes: * always update 'nameserver' & 'search' entries when DNS* & DOMAIN options (respectively) were updated in ifcfg-* files * always update the order of 'nameserver' entries when the order of DNS* options was updated * always keep /etc/resolv.conf.save as a proper backup - do not overwrite it everytime when updating 'nameserver' or 'search' Enhancements: * added support for DNS3 option (equals to MAXNS value in GLIBC) * added logic to process duplicate DNS* options * added logic to process randomly omitted DNS* options (e.g. omitting DNS1 while specifying DNS2 and/or DNS3 will still work now) This work was based on these two RHEL-7.5 BZs: https://bugzilla.redhat.com/show_bug.cgi?id=1364895 https://bugzilla.redhat.com/show_bug.cgi?id=1357658
Diffstat (limited to 'sysconfig/network-scripts/ifup-post')
-rwxr-xr-xsysconfig/network-scripts/ifup-post141
1 files changed, 84 insertions, 57 deletions
diff --git a/sysconfig/network-scripts/ifup-post b/sysconfig/network-scripts/ifup-post
index 41956e7e..bcca632e 100755
--- a/sysconfig/network-scripts/ifup-post
+++ b/sysconfig/network-scripts/ifup-post
@@ -28,67 +28,94 @@ if ! is_true "$NOROUTESET"; then
fi
-if ! is_false "$PEERDNS" || [ -n "$RESOLV_MODS" ] && ! is_false "$RESOLV_MODS"; then
- [ -n "$MS_DNS1" ] && DNS1=$MS_DNS1
- [ -n "$MS_DNS2" ] && DNS2=$MS_DNS2
-
- if [ -z "$DNS1" -a -n "$DNS2" ]; then
- DNS1=$DNS2
- DNS2=
+if ! is_false "${PEERDNS}" || ! is_false "${RESOLV_MODS}"; then
+ # Obtain the DNS entries when using PPP if necessary:
+ [ -n "${MS_DNS1}" ] && DNS1="${MS_DNS1}"
+ [ -n "${MS_DNS2}" ] && DNS2="${MS_DNS2}"
+
+ # Remove duplicate DNS entries and shift them, if necessary:
+ update_DNS_entries
+
+ # Determine what regexp we should use (for testing below):
+ if [ -n "${DNS3}" ]; then
+ grep_regexp="[^#]?nameserver[[:space:]]+${DNS1}[^#]?nameserver[[:space:]]+${DNS2}[^#]?nameserver[[:space:]]+${DNS3}"
+ elif [ -n "${DNS2}" ]; then
+ grep_regexp="[^#]?nameserver[[:space:]]+${DNS1}[^#]?nameserver[[:space:]]+${DNS2}"
+ elif [ -n "${DNS1}" ]; then
+ grep_regexp="[^#]?nameserver[[:space:]]+${DNS1}"
+ else
+ # No DNS entries used at all ->> match everything.
+ grep_regexp=".*"
fi
- if ( [ -n "$DNS1" ] && ! grep -q "^nameserver $DNS1" /etc/resolv.conf ) ||
- ( [ -n "$DNS2" ] && ! grep -q "^nameserver $DNS2" /etc/resolv.conf ) &&
- tr=$(mktemp /tmp/XXXXXX) ; then
- current_replacement="$DNS1"
- next_replacement="$DNS2"
- search=
- (cat /etc/resolv.conf ; echo EOF ; echo EOF) | while read answer ; do
- case $answer in
- nameserver*|EOF)
- if [ -n "$current_replacement" ] ; then
- echo "nameserver $current_replacement" >> $tr
- if [ -n "$next_replacement" ] ; then
- current_replacement="$next_replacement"
- next_replacement=
- else
- current_replacement=
- fi
- else
- if [ "$answer" != EOF ] ; then
- echo "$answer" >> $tr
- fi
- fi
- ;;
- domain*|search*)
- if [ -n "$DOMAIN" ]; then
- echo "$answer" | while read key value ; do
- search="$search $value"
- done
- else
- echo "$answer" >> $tr
- fi
- ;;
- *)
- echo "$answer" >> $tr
- ;;
- esac
- done
- if [ -n "$DOMAIN" ]; then
- echo "search $DOMAIN $search" >> $tr
+ # Test if the search field needs updating, or
+ # if the nameserver entries order should be updated:
+ if [ -n "${DOMAIN}" ] && ! grep -q "^search.*${DOMAIN}.*$" /etc/resolv.conf ||
+ ! tr --delete '\n' < /etc/resolv.conf | grep -E -q "${grep_regexp}"; then
+
+ if tmp_file=$(mktemp); then
+ search_str=''
+
+ while read line; do
+ case ${line} in
+
+ # Skip nameserver entries when at least one DNS option was given
+ # (at this stage we know that we have to update all the nameserver
+ # enries anyway -- see below), or copy them if we are changing just
+ # the 'search' field in /etc/resolv.conf:
+ nameserver*)
+ if [[ "${grep_regexp}" != ".*" ]]; then
+ continue
+ else
+ echo "${line}" >> "${tmp_file}"
+ fi
+ ;;
+
+ domain* | search*)
+ if [ -n "${DOMAIN}" ]; then
+ read search value < <(echo ${line})
+ search_str+=" ${value}"
+ else
+ echo "${line}" >> "${tmp_file}"
+ fi
+ ;;
+
+ # Keep the rest of the /etc/resolv.conf as it was:
+ *)
+ echo "${line}" >> "${tmp_file}"
+ ;;
+ esac
+ done < /etc/resolv.conf
+
+ # Insert the domain into 'search' field:
+ if [ -n "${DOMAIN}" ]; then
+ echo "search ${DOMAIN}${search_str}" >> "${tmp_file}"
+ fi
+
+ # Add the requested nameserver entries:
+ [ -n "${DNS1}" ] && echo "nameserver ${DNS1}" >> "${tmp_file}"
+ [ -n "${DNS2}" ] && echo "nameserver ${DNS2}" >> "${tmp_file}"
+ [ -n "${DNS3}" ] && echo "nameserver ${DNS3}" >> "${tmp_file}"
+
+ # Backup resolv.conf only if it doesn't exist already:
+ ! [ -f /etc/resolv.conf.save ] && cp -af /etc/resolv.conf /etc/resolv.conf.save
+
+ # Maintain permissions, but set umask in case it doesn't exist:
+ umask_old=$(umask)
+ umask 022
+
+ # Update the resolv.conf:
+ change_resolv_conf "${tmp_file}"
+
+ rm -f "${tmp_file}"
+ umask ${umask_old}
+ unset tmp_file search_str umask_old
+ else
+ net_log $"/etc/resolv.conf was not updated: failed to create temporary file" 'err' 'ifup-post'
fi
-
- # backup resolv.conf
- cp -af /etc/resolv.conf /etc/resolv.conf.save
-
- # maintain permissions
- # but set umask in case it doesn't exist!
- oldumask=$(umask)
- umask 022
- change_resolv_conf $tr
- rm -f $tr
- umask $oldumask
fi
+
+ unset grep_regexp
fi
# don't set hostname on ppp/slip connections