File to flag if the system needs restart

Creates /var/run/needs_restarting file if any "critical" package got
upgraded. As the /var/run/ is ephemeral and renewed each boot, the
file disappears after reboot.

The packages that flags the restart need are:

- kernel-generic, kernel-huge: as a new kernel needs a restart to be
  running.
- glibc, glibc-solibs: Restart is the only way to be sure that all
  running binaries are using the new glibc.
- eudev, elogind, dbus: those provides some very basic system
  services.
- openssl, openssl-solibs: security bugs on those libs are dangerous,
  the reboot makes sure that all running binaries are using the newer
  version.

files/core-functions.sh

@@ -1318,6 +1318,28 @@ for slackpkg to work properly.
 	fi
 }	
 
+# Checks if a critical package were upgraded by Slackpkg.
+# The /var/run/needs_restarting file contains the list of upgraded
+# packages.
+#
+# The file only is created if /var/run filesystem type is tmpfs so
+# the reboot will clean it
+function needs_restarting() {
+	if [ "$(stat -f -c %T /var/run/)" = "tmpfs" ]; then
+		find $ROOT/var/log/packages/ -cnewer $TMPDIR/timestamp -type f \( \
+			-name "kernel-generic-[0-9]*" -o \
+			-name "kernel-huge-[0-9]*" -o \
+			-name "openssl-solibs-[0-9]*" -o \
+			-name "openssl-[0-9]*" -o \
+			-name "glibc-[0-9]*" -o \
+			-name "aaa_glibc-solibs-[0-9]*" -o \
+			-name "eudev-[0-9]*" -o \
+			-name "elogind-[0-9]*" -o \
+			-name "dbus-[0-9]*" \) | \
+		awk -F/ '{ print $NF }' >> $ROOT/var/run/needs_restarting
+	fi
+}
+
 function remove_pkg() {
 	local i
 
@@ -1342,6 +1364,7 @@ function upgrade_pkg() {
 	for i in $SHOWLIST; do
 		getpkg $i upgradepkg Upgrading
 	done
+	needs_restarting
 }
 
 function install_pkg() {