dhclient: T3471: Fixed process search for IPv4

Some software starts dhclient without IP protocol flag (`-4`, `-6`),
this commit adds the ability to find such processes as well as with a
protocol flag.
Additionally, to handle rare situations when PID file may not exists
(most likely, when multiple dhclient processes started with the same
PID file path), added last-resort action to kill such dhclients.

1 files changed, 16 insertions, 7 deletions

diff --git a/src/etc/dhcp/dhclient-enter-hooks.d/02-vyos-stopdhclient b/src/etc/dhcp/dhclient-enter-hooks.d/02-vyos-stopdhclient
index 939055a63..f737148dc 100644
--- a/src/etc/dhcp/dhclient-enter-hooks.d/02-vyos-stopdhclient
+++ b/src/etc/dhcp/dhclient-enter-hooks.d/02-vyos-stopdhclient
@@ -2,26 +2,35 @@
 if [ -z ${CONTROLLED_STOP} ] ; then
     # stop dhclient for this interface, if it is not current one
     # get PID for current dhclient
-    current_dhclient=`ps --no-headers --format ppid --pid $$ | awk '{ print $1 }'`
+    current_dhclient=`ps --no-headers --format ppid --pid $$ | awk '{ print \$1 }'`
 
     # get PID for master process (current can be a fork)
-    master_dhclient=`ps --no-headers --format ppid --pid $current_dhclient | awk '{ print $1 }'`
+    master_dhclient=`ps --no-headers --format ppid --pid $current_dhclient | awk '{ print \$1 }'`
 
     # get IP version for current dhclient
-    ipversion_arg=`ps --no-headers --format args --pid $current_dhclient | awk '{ print $2 }'`
+    ipversion_arg=`ps --no-headers --format args --pid $current_dhclient | awk 'match(\$0, /\s-(4|6)\s/, IPV) { printf("%s", IPV[1]) }'`
 
     # get list of all dhclient running for current interface
-    dhclients_pids=(`pgrep -f "dhclient $ipversion_arg.* $interface(\s|$)"`)
+    if [[ $ipversion_arg == "6" ]]; then
+        dhclients_pids=(`pgrep -f "dhclient.*\s-6\s.*\s$interface(\s|$)"`)
+    else
+        dhclients_pids=(`ps --no-headers --format pid,args -C dhclient | awk "{ if(match(\\$0, /\s${interface}(\s|$)/) && !match(\\$0, /\s-6\s/)) printf(\"%s\n\", \\$1) }"`)
+    fi
 
     logmsg info "Current dhclient PID: $current_dhclient, Parent PID: $master_dhclient, IP version: $ipversion_arg, All dhclients for interface $interface: ${dhclients_pids[@]}"
     # stop all dhclients for current interface, except current one
     for dhclient in ${dhclients_pids[@]}; do
         if ([ $dhclient -ne $current_dhclient ] && [ $dhclient -ne $master_dhclient ]); then
-            logmsg info "Stopping dhclient with PID: ${dhclient}"
             # get path to PID-file of dhclient process
-            local dhclient_pidfile=`ps --no-headers --format args --pid $dhclient | awk 'match($0, ".*-pf (/.*pid) .*", PF) { print PF[1] }'`
+            local dhclient_pidfile=`ps --no-headers --format args --pid $dhclient | awk 'match(\$0, ".*-pf (/.*pid) .*", PF) { print PF[1] }'`
             # stop dhclient with native command - this will run dhclient-script with correct reason unlike simple kill
-            dhclient -e CONTROLLED_STOP=yes -x -pf $dhclient_pidfile
+            logmsg info "Stopping dhclient with PID: ${dhclient}, PID file: $dhclient_pidfile"
+            if [[ -e $dhclient_pidfile ]]; then
+                dhclient -e CONTROLLED_STOP=yes -x -pf $dhclient_pidfile
+            else
+                logmsg error "PID file $dhclient_pidfile does not exists, killing dhclient with SIGTERM signal"
+                kill -s 15 ${dhclient}
+            fi
         fi
     done
 fi