system: add optional swap file for SSD; closes #1554

(cherry picked from commit 77401d6a)

plist

@@ -131,6 +131,7 @@
 /usr/local/etc/rc.rfc2136
 /usr/local/etc/rc.shutdown
 /usr/local/etc/rc.sshd
+/usr/local/etc/rc.swapon
 /usr/local/etc/rc.syshook
 /usr/local/etc/rc.syshook.d/05-beep.stop
 /usr/local/etc/rc.syshook.d/05-update.early

src/etc/rc

@@ -203,7 +203,7 @@ rm -f /var/run/nologin
 
 # set up and recover a crash dump before activating swap
 /usr/local/etc/rc.crashdump
-swapon -a
+/usr/local/etc/rc.swapon
 
 # write /var/run/dmesg.boot
 /etc/rc.d/dmesg onestart

src/etc/rc.swapon

+#!/bin/sh
+
+# Copyright (c) 2017 Franco Fichtner <franco@opnsense.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+SWAPUSE=$(grep -c use_swap_file /conf/config.xml)
+SWAPFILE=/usr/swap0
+SWAPSIZE=2048
+SWAPDEV=md98
+
+# auto-configured fstab entries:
+
+swapon -a
+
+# swap file option for SSDs:
+
+if [ "${SWAPUSE}" != "0" ]; then
+	if [ ! -f ${SWAPFILE} ]; then
+		dd if=/dev/zero of=${SWAPFILE} bs=1m count=${SWAPSIZE}
+		chmod 0600 ${SWAPFILE}
+	fi
+	if mdconfig -a -t vnode -f ${SWAPFILE} -u ${SWAPDEV}; then
+		swapon /dev/${SWAPDEV}
+	fi
+else
+	rm -f ${SWAPFILE}
+fi

src/www/system_advanced_misc.php

@@ -82,6 +82,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     /* if the old use_mfs_tmpvar is found, set these flags, too */
     $pconfig['use_mfs_var'] = isset($config['system']['use_mfs_tmpvar']) || isset($config['system']['use_mfs_var']);
     $pconfig['use_mfs_tmp'] = isset($config['system']['use_mfs_tmpvar']) || isset($config['system']['use_mfs_tmp']);
+    $pconfig['use_swap_file'] = isset($config['system']['use_swap_file']);
     $pconfig['rrdbackup'] = !empty($config['system']['rrdbackup']) ? $config['system']['rrdbackup'] : null;
     $pconfig['dhcpbackup'] = !empty($config['system']['dhcpbackup']) ? $config['system']['dhcpbackup'] : null;
     $pconfig['netflowbackup'] = !empty($config['system']['netflowbackup']) ? $config['system']['netflowbackup'] : null;
@@ -157,6 +158,13 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             unset($config['system']['use_mfs_tmp']);
         }
 
+        if (!empty($pconfig['use_swap_file'])) {
+            /* set explicit value here in case we want to make it flexible */
+            $config['system']['use_swap_file'] = 2048;
+        } elseif (isset($config['system']['use_swap_file'])) {
+            unset($config['system']['use_swap_file']);
+        }
+
         if (!empty($pconfig['rrdbackup'])) {
             $config['system']['rrdbackup'] = $pconfig['rrdbackup'];
         } elseif (isset($config['system']['rrdbackup'])) {
@@ -449,7 +457,14 @@ include("head.inc");
                 </td>
               </tr>
               <tr>
-                <th colspan="2" valign="top" class="listtopic"><?=gettext("RAM Disk Settings (Reboot to Apply Changes)"); ?></th>
+                <th colspan="2" valign="top" class="listtopic"><?=gettext("Disk / Memory Settings (reboot to apply changes)"); ?></th>
+              </tr>
+              <tr>
+                <td><i class="fa fa-info-circle text-muted"></i> <?=gettext('Swap file'); ?></td>
+                <td>
+                  <input name="use_swap_file" type="checkbox" id="use_swap_file" value="yes" <?=!empty($pconfig['use_swap_file']) ? 'checked="checked"' : '';?>/>
+                  <strong><?= gettext('Add a 2 GB swap file to the system') ?></strong>
+                </td>
               </tr>
               <tr>
                 <td><a id="help_for_use_mfs_var" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext('/var RAM disk'); ?></td>