Migrate service enabled/disabled status from sysvinit to systemd on upgrade

1 files changed, 131 insertions, 24 deletions

diff --git a/add-service b/add-service
index fb17a43..bd51d86 100755
--- a/add-service
+++ b/add-service
@@ -40,31 +40,55 @@ else
 fi
 units="$*"			# systemd units
 units_to_enable=		# units enabled by msec
+systemd_migration_dir=/var/lib/rpm-helper/systemd-migration
+mkdir -p "${systemd_migration_dir}"
+
+SYSTEMUNITDIR=/lib/systemd/system
+USERUNITDIR=/etc/systemd/system
+RUNTIMEUNITDIR=/run/systemd/system
+
+find_unit() {
+    unit=$(basename $1)
+
+    # We need to normalise the systemd unit name as the native unit may not have
+    # the same filename (sans it's .service suffix) as sysvinit script.
+    # In this case, symlinks are used to mask the sysvinit file, but for enabling
+    # and disabling units we must use the official name.
+
+    searchunit=
+    if [ -f "$SYSTEMUNITDIR/$unit" ]; then
+        if [ -L "$SYSTEMUNITDIR/$unit" ]; then
+            searchunit=$(/usr/bin/readlink "$SYSTEMUNITDIR/$unit")
+        else
+            searchunit="$SYSTEMUNITDIR/$unit"
+        fi
+    elif [ -f "$USERUNITDIR/$unit" ]; then
+        if [ -L "$USERUNITDIR/$unit" ]; then
+            searchunit=$(/usr/bin/readlink "$USERUNITDIR/$unit")
+        else
+            searchunit="$USERUNITDIR/$unit"
+        fi
+    elif [ -f "$RUNTIMEUNITDIR/$unit" ]; then
+        if [ -L "$RUNTIMEUNITDIR/$unit" ]; then
+            searchunit=$(/usr/bin/readlink "$RUNTIMEUNITDIR/$unit")
+        else
+            searchunit="$RUNTIMEUNITDIR/$unit"
+        fi
+    fi
+    if [ -n "$searchunit" ]; then
+        echo -n $searchunit
+    fi
+}
+
 
 # If only a sysvinit service is given, then deal with a systemd unit of the same
 # name. Specific specs can enable specific unit names as needed but this should
 # catch the most common usage.
 if [ -z "$units" ]; then
   units="$srv.service"
-
-  # We need to normalise the systemd unit name as the native unit may not have
-  # the same filename (sans it's .service suffix) as sysvinit script.
-  # In this case, symlinks are used to mask the sysvinit file, but for enabling
-  # and disabling units we must use the official name.
-  SYSTEMUNITDIR=/lib/systemd/system
-  USERUNITDIR=/etc/systemd/system
-  RUNTIMEUNITDIR=/run/systemd/system
-
-  searchunit=
-  if [ -f "$SYSTEMUNITDIR/$units" ]; then
-    searchunit=$(/usr/bin/readlink "$SYSTEMUNITDIR/$units")
-  elif [ -f "$USERUNITDIR/$units" ]; then
-    searchunit=$(/usr/bin/readlink "$USERUNITDIR/$units")
-  elif [ -f "$RUNTIMEUNITDIR/$units" ]; then
-    searchunit=$(/usr/bin/readlink "$RUNTIMEUNITDIR/$units")
-  fi
+  searchunit=$(find_unit $units)
   if [ -n "$searchunit" ]; then
-    units=$searchunit
+    units=$(basename $searchunit)
   fi
 fi
 
@@ -112,6 +136,12 @@ add_service() {
     if [ -n "$units_to_enable" ]; then
         /bin/systemctl --quiet enable $units_to_enable >/dev/null
     fi
+
+    # When no native systemd unit exists, the above command will actually
+    # just end up running chkconfig anyway, but if a native systemd unit exists
+    # the legacy init script will not be enabled.
+    # In order to enable switching back ot sysvinit, we should enable the
+    # sysvinit scripts too.
     if [ -n "$srv" -a -f /etc/rc.d/init.d/$srv ]; then
         /sbin/chkconfig --add $srv
 
@@ -131,20 +161,97 @@ add_service() {
     fi
 }
 
+check_sysvinit_service() {
+    rl=$1
+    srv=$2
+
+    set -- /etc/rc${rl}.d/S??$srv
+    if [ $# -gt 1 ]; then
+        echo 1>&2 "add-service: Error: $srv appears multiple times at runlevel $rl: $*"
+    fi
+
+    echo -n $1
+}
 if [ $num = 1 ]; then
     # First install mode
     add_service
 else
     # Upgrade mode.
+
+    # Handle migration to systemd.
+    # If a previously installed package only had a sysvinit script, but an
+    # updated package has a native systemd unit, we need to make sure we migrate
+    # any service enablement for various targets (née runlevels)
+    if [ -n "$srv" -a -n "$units" ]; then
+        if [ ! -f "${systemd_migration_dir}/$srv" ]; then
+            full_path_units=
+            for unit in $units; do
+                # We need a full path for the symlink. Also it's possible
+                # that $unit contains "foo.service" where foo is actually
+                # a sysvinit script and thus we'll not have anything native.
+                # We only consider a "migration" to have taken place when
+                # we genuinely have a native systemd unit.
+                unit=$(find_unit $unit)
+                if [ -n "$unit" ]; then
+                    full_path_units="$full_path_units $unit"
+                fi
+            done
+
+            if [ -n "$full_path_units" ]; then
+                enable_targets=
+                # We have not yet migrated this service
+                # First we check in which runlevels the legacy service is enabled
+                # Only bother checking runlevels 1 3 and 5
+                script=$(check_sysvinit_service 1 $srv)
+
+                # NB We only check that the link exists as the old sysvinit
+                # script may have been removed during migration to systemd
+                # native unit.
+                if [ -L "$script" ]; then
+                    enable_targets="$enable_targets rescue.target"
+                fi
+
+                script=$(check_sysvinit_service 3 $srv)
+                if [ -L "$script" ]; then
+                    enable_targets="$enable_targets multi-user.target"
+                else
+                    # As graphical.target includes everything in multi-user.target,
+                    # we only need to check 5 when 3 does NOT give us a result.
+                    script=$(check_sysvinit_service 5 $srv)
+                    if [ -L "$script" ]; then
+                        enable_targets="$enable_targets graphical.target"
+                    fi
+                fi
+
+                if [ -n "$enable_targets" ]; then
+                    for enable_target in $enable_targets; do
+                        wantsdir=$USERUNITDIR/${enable_target}.wants
+                        mkdir -p $wantsdir
+                        for unit in $full_path_units; do
+                            if [ ! -f $wantsdir/$(basename $unit) ]; then
+                                echo 1>&2 "Migrating sysvinit service '$srv' to systemd native unit '$(basename $unit)' for target '${enable_target}'"
+                                ln -s $unit $wantsdir/$(basename $unit)
+                            fi
+                        done
+                    done
+                    if [ x$init = xsystemd ]; then
+                        /bin/systemctl --system daemon-reload
+                    fi
+                fi
+
+                # It could be that a package is installed but not enabled.
+                # If that is the case, we should still consider it "migrated"
+                # even when we do not enable anything.
+                touch "${systemd_migration_dir}/$srv"
+            fi
+        fi
+    fi
+
     if [ x$init = xsystemd ]; then
         /bin/systemctl --quiet try-restart $units
     elif [ -f /etc/rc.d/init.d/$srv ]; then
-        set -- /etc/rc3.d/S??$srv
-        if [ $# -gt 1 ]; then
-            echo 1>&2 "add-service: Error: $srv appears multiple times: $*"
-        fi
-
-        if [ -f "$1" ]; then
+        script=$(check_sysvinit_service 3 $srv);
+        if [ -f "$script" ]; then
             /sbin/chkconfig --add $srv
         fi