Introducing sysutils/swapmon.

This port attempts to monitor swap usage and dynamically add a swapfile as
neccessary.

PR:		ports/148711
Submitted by:	Alexander Kuehn <freebsd@nagilum.org>
Approved by:	wxs (mentor)

5 files changed, 357 insertions, 0 deletions

diff --git a/sysutils/swapmon/Makefile b/sysutils/swapmon/Makefile
new file mode 100644
index 00000000000..deb1bf5d4e9
--- /dev/null
+++ b/sysutils/swapmon/Makefile
@@ -0,0 +1,40 @@
+# ports collection makefile for: swapmon
+# Date Created:		27 July 2010
+# Whom:                 Alexander Kuehn <freebsd@nagilum.org>
+#
+# $FreeBSD$
+#
+
+PORTNAME=	swapmon
+PORTVERSION=	1.4
+CATEGORIES=	sysutils
+MASTER_SITES=	# none
+DISTFILES=	# none
+
+MAINTAINER=	freebsd@nagilum.org
+COMMENT=	Add/remove swapspace as needed
+
+LICENSE=	BSD
+
+NO_BUILD=	yes
+MAN1=		${PORTNAME}.1
+
+USE_RC_SUBR=	${PORTNAME}
+
+PLIST_FILES=	sbin/${PORTNAME}
+
+do-install:
+	@${SED} -e 's|%%PREFIX%%|${PREFIX}|g' ${FILESDIR}/${PORTNAME}.sh.in \
+		> ${WRKDIR}/${PORTNAME}.sh
+	${INSTALL_SCRIPT} ${WRKDIR}/${PORTNAME}.sh ${PREFIX}/sbin/${PORTNAME}
+	${INSTALL_MAN} ${FILESDIR}/${PORTNAME}.1 ${PREFIX}/man/man1
+
+post-install:
+	@${ECHO_MSG}	""
+	@${ECHO_MSG}	"To have swapmon run automatically after each boot"
+	@${ECHO_MSG}	"execute the following command as root:"
+	@${ECHO_MSG}	""
+	@${ECHO_MSG}	"  echo '${PORTNAME}_enable=\"YES\"' >>/etc/rc.conf"
+	@${ECHO_MSG}	""
+
+.include <bsd.port.mk>
diff --git a/sysutils/swapmon/files/swapmon.1 b/sysutils/swapmon/files/swapmon.1
new file mode 100644
index 00000000000..0b2377cd131
--- /dev/null
+++ b/sysutils/swapmon/files/swapmon.1
@@ -0,0 +1,88 @@
+.\"Modified from man(1) of FreeBSD, the NetBSD mdoc.template, and mdoc.samples.
+.\"See Also:
+.\"man mdoc.samples for a complete listing of options
+.\"man mdoc for the short list of editing options
+.\"/usr/share/misc/mdoc.template
+.Dd Wed Jul 20 2010               \" DATE 
+.Dt swapmon 1      \" Program name and manual section number 
+.Os FreeBSD
+.Sh NAME                 \" Section Header - required - don't modify 
+.Nm swapmon
+.\" The following lines are read in generating the apropos(man -k) database. Use only key
+.\" words here as the database is built based on the words here and in the .ND line. 
+.Nd monitor swapusage, add swapspace as needed
+.Sh SYNOPSIS             \" Section Header - required - don't modify
+.Nm
+.Op Ar start|stop|-F
+add/remove swapspace automatically as needed
+.Sh DESCRIPTION          \" Section Header - required - don't modify
+.Nm
+will check the current swapusage and if more than SWAP_HIGH percent of swapspace is in use it will create a new swapfile with a size of size of SWAP_STEP percent of the current swapspace and activate it.
+If less than SWAP_LOW percent of swapspace is in use it will deactivate a previously added swapspace file and remove it.
+.Pp                      \" Inserts a space
+If called with
+.Ar start
+it will fork into the background and run as a daemon. It will check and then sleep for DELAY seconds before checking again. Messages about the operation will be piped to LOGGER. The pid of the daemon will be written to PIDFILE.
+.Pp                      \" Inserts a space
+If called with
+.Ar stop
+it stop a previously forked swapmon daemon.
+.Pp                      \" Inserts a space
+If called with
+.Ar -F
+it will run as a daemon but not detach from the terminal. Messages will still be piped to LOGGGER and not to the terminal by default. You may specify "/bin/cat" as LOGGER to get the messages on the terminal.
+.Pp                      \" Inserts a space
+Default values:
+.Bl -tag -width -indent  \" Begins a tagged list 
+.It SWAP_HIGH               \" Each item preceded by .It macro
+75
+.It SWAP_LOW               \" Each item preceded by .It macro
+45
+.It SWAP_STEP               \" Each item preceded by .It macro
+100-SWAP_HIGH (=25)
+.It SM_HOME
+"/usr/.swap/"
+.It DELAY               \" Each item preceded by .It macro
+30
+.It LOGGER             \" Each item preceded by .It macro
+/usr/bin/logger
+.It PIDFILE               \" Each item preceded by .It macro
+/var/run/swapmon.pid
+.El                      \" Ends the list
+.Pp
+swapmon can be called via cron(5). In that case you would receive messages about the swapspace being adjusted via e-mail. To use it that way add a crontab entry to the root crontab similar to this:
+.Bl -tag -width -indent  \" Differs from above in tag removed 
+.It * *  * * *  /usr/local/sbin/swapmon
+.El                      \" Ends the list
+.Pp
+.\" .Sh ENVIRONMENT      \" May not be needed
+.\" .Bl -tag -width "ENV_VAR_1" -indent \" ENV_VAR_1 is width of the string ENV_VAR_1
+.\" .It Ev ENV_VAR_1
+.\" Description of ENV_VAR_1
+.\" .It Ev ENV_VAR_2
+.\" Description of ENV_VAR_2
+.\" .El                      
+.Sh FILES                \" File used or created by the topic of the man page
+.Bl -tag -width "/usr/local/etc/swapmonrc" -compact
+.It Pa /usr/local/etc/swapmonrc
+optional configuration file for overwriting the defaults above
+.It Pa $SM_HOME
+The "homedirectory" of swapmon. In here the swapfiles as well as a lockfile and the swapfile list will be created.
+.\" .Sh DIAGNOSTICS       \" May not be needed
+.\" .Bl -diag
+.\" .It Diagnostic Tag
+.\" Diagnostic informtion here.
+.\" .It Diagnostic Tag
+.\" Diagnostic informtion here.
+.\" .El
+.Sh SEE ALSO 
+.\" List links in ascending order by section, alphabetically within a section.
+.\" Please do not reference files that do not exist without filing a bug report
+.Xr swapctl 8 , 
+.Xr mdconfig 8 ,
+.Xr truncate 8 ,
+.Xr logger 1 ,
+.Xr crontab 5
+.\" .Sh BUGS              \" Document known, unremedied bugs 
+.\" .Sh HISTORY           \" Document history if command behaves in a unique manner 
+
diff --git a/sysutils/swapmon/files/swapmon.in b/sysutils/swapmon/files/swapmon.in
new file mode 100644
index 00000000000..7d1da4b5f11
--- /dev/null
+++ b/sysutils/swapmon/files/swapmon.in
@@ -0,0 +1,33 @@
+#!/bin/sh
+#
+# swapmon - add / remove swap as needed
+#  
+# PROVIDE: swapmon
+# REQUIRE: LOGIN
+# KEYWORD: shutdown
+#
+# Add the following lines to /etc/rc.conf to enable swapmon:
+#
+#swapmon_enable="YES"
+#
+. /etc/rc.subr
+
+name=swapmon
+rcvar=`set_rcvar`
+
+command="%%PREFIX%%/sbin/${name}"
+command_interpreter="/bin/sh"
+
+CONFIG=%%PREFIX%%/etc/${name}rc
+if [ -r "${CONFIG}" ]
+then	. "${CONFIG}"
+fi
+pidfile=${PIDFILE:-"/var/run/${name}.pid"}
+swapmon_enable=${swapmon_enable:-"NO"}
+
+load_rc_config ${name}
+start_precmd='command_args="-F <&- 2>&1 >/dev/null &"'
+stop_postcmd='rm $pidfile'
+
+run_rc_command "$1"
+
diff --git a/sysutils/swapmon/files/swapmon.sh.in b/sysutils/swapmon/files/swapmon.sh.in
new file mode 100644
index 00000000000..7e135d0f6aa
--- /dev/null
+++ b/sysutils/swapmon/files/swapmon.sh.in
@@ -0,0 +1,187 @@
+#!/bin/sh
+#
+# swapmon - add / remove swap as needed
+#  
+# Copyright (C) 2010 Alexander Kuehn. All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 
+# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+# 
+
+CONFIG=%%PREFIX%%/etc/swapmonrc
+VERSION="1.4"
+
+if [ -r "${CONFIG}" ]
+then	. "${CONFIG}"
+fi
+
+# where to create swapfiles 
+: ${SM_HOME=/usr/.swap}
+# if the swap usage is higher than that (percentage) new swap will be added 
+: ${SWAP_HIGH=75}
+# if the swap usage is lower than that then a previously added swapfile will be removed
+: ${SWAP_LOW=45}
+# if swap is running low we will increase the swapspace by this many percent
+: ${SWAP_STEP=$(( 100 - ${SWAP_HIGH} ))}
+# if running as daemon how long to wait between checks
+: ${DELAY=30}
+# if running as daemon where to log messages
+: ${LOGGER=/usr/bin/logger}
+# if running as daemon where to put pidfile
+: ${PIDFILE=/var/run/swapmon.pid}
+
+LOCKF=$SM_HOME/lock
+SWAPFILE=$SM_HOME/swap.XXXX
+SWAPLIST=$SM_HOME/swapfiles
+MKTEMP=/usr/bin/mktemp
+TRUNCATE=/usr/bin/truncate
+TOUCH=/usr/bin/touch
+CHMOD=/bin/chmod
+MDCONFIG=/sbin/mdconfig
+SWAPON=/sbin/swapon
+SWAPOFF=/sbin/swapoff
+SWAPCTL=/sbin/swapctl
+RM=/bin/rm
+SED=/usr/bin/sed
+umask 0077
+
+if [ $(/usr/bin/id -u) -gt 0 ]
+then	echo "I'm not running as root (uid=0) this probably wont work."
+#	exit 1
+fi
+
+if [ \! -d ${SM_HOME} ]
+then	/bin/mkdir -p ${SM_HOME} || { echo "Error creating ${SM_HOME}!" ; exit 1; }
+fi
+$TOUCH ${SWAPLIST} || { echo "Can't write to ${SWAPLIST} aborting." ; exit 1; }
+# add a 1MB swapfile to check if we have the permissions to do so
+NSWAP=$($MKTEMP ${SWAPFILE})
+$TRUNCATE -s 1M "${NSWAP}" || { echo "Error creating swapfile ${NSWAP}, aborting." ; exit 1; }
+$CHMOD 600 "${NSWAP}"
+MDEV=$($MDCONFIG -a -t vnode -f "${NSWAP}")
+if [ -n "$MDEV" ]
+then
+	$SWAPON /dev/${MDEV} || { echo "error activating swapdevice /dev/${MDEV}."; exit 1; }
+	$SWAPOFF "/dev/${MDEV}"
+	$MDCONFIG -d -u ${MDEV} >/dev/null
+	$RM -f "${NSWAP}"
+else
+	echo "error configuring memory disk ($MDCONFIG -a -t vnode -f \"${NSWAP}\")"
+	$RM -f "${NSWAP}"
+	exit
+fi
+
+if [ ${SWAP_LOW} -ge $(( $(($SWAP_HIGH * 100)) / $((100 + $SWAP_STEP)) )) ]
+then	echo "SWAP_LOW(${SWAP_LOW}) schould be lower than $(( $(($SWAP_HIGH * 100)) / $((100 + $SWAP_STEP)) )) to be useful."
+		echo "Swapmon $VERSION."
+		exit 1
+fi
+
+check_swap()
+{
+	SWAPCTLSK=$($SWAPCTL -sk)
+	SWAPTOTAL=${SWAPCTLSK#* }
+	SWAPTOTAL=${SWAPTOTAL% *}
+	SWAPUSAGE=$(( ${SWAPCTLSK##* } * 100 / $SWAPTOTAL ))
+	if [ ${SWAPUSAGE} -gt ${SWAP_HIGH} ]
+	then	NSWAP=$($MKTEMP ${SWAPFILE})
+		BLOCKS=$(( $(( ${SWAPTOTAL} * ${SWAP_STEP} +1023)) / 102400 ))
+		# make sure we can write to the swaplist
+		$TOUCH "${SWAPLIST}" || { echo "swapmon$VERSION[$$] Error modifying ${SWAPLIST} exiting."|$LOGGER; exit 1; }
+		$TRUNCATE -s ${BLOCKS}M "${NSWAP}"
+		$CHMOD 0600 "${NSWAP}"
+		if [ -s "${NSWAP}" ]
+		then	MDEV=$($MDCONFIG -a -t vnode -f "${NSWAP}")
+			printf "${MDEV} ${NSWAP}\n" >>"${SWAPLIST}"
+			echo "swapmon$VERSION[$$] Swapusage ${SWAPUSAGE}%($((${SWAPCTLSK##* }/1024))/$(($SWAPTOTAL/1024)) M), activated new swapdevice ${MDEV} backed by ${NSWAP}."|$LOGGER
+			$SWAPON /dev/${MDEV}
+			$SWAPCTL -lh|$SED -e "s/^/swapmon$VERSION[$$] /g"|$LOGGER
+		else	echo "swapmon$VERSION[$$] Creating swapfile ${NSWAP} failed! :("|$LOGGER
+		fi
+	fi
+	while [ \( ${SWAPUSAGE} -lt ${SWAP_LOW} \) -a -s "${SWAPLIST}" ]
+	do	MDEV=$(/usr/bin/tail -1 "${SWAPLIST}")
+		SWAPF=${MDEV#* }
+		MDEV=${MDEV%% *}
+		if [ -s "${SWAPF}" ]
+		then	if [ "${SWAPF}" = "$($MDCONFIG -l -u ${MDEV}|/usr/bin/awk '{print $4}')" ]
+			then	if [ -n "$($SWAPCTL -l|$SED -n '1!p'|/usr/bin/grep '/dev/'${MDEV})" ]
+				then	echo "swapmon$VERSION[$$] Swapusage ${SWAPUSAGE}%($((${SWAPCTLSK##* }/1024))/$(($SWAPTOTAL/1024)) M), deactivating swapdevice ${MDEV}."|$LOGGER
+					$SWAPCTL -lh|$SED -e "s/^/swapmon$VERSION[$$] /g"|$LOGGER
+					$SWAPOFF "/dev/${MDEV}"
+				fi
+				echo "swapmon$VERSION[$$] Detaching vnode ${MDEV}."|$LOGGER
+				$MDCONFIG -d -u ${MDEV} >/dev/null
+				$RM -f "${SWAPF}"
+			else	echo "swapmon$VERSION[$$] Swapfile ${SWAPF} is not attached to ${MDEV} as it should be!?"|$LOGGER
+				for MDEV in $($MDCONFIG -l)
+				do	echo "swapmon$VERSION[$$] $($MDCONFIG -l -u ${MDEV})"|$LOGGER
+				done
+			fi
+		else	echo "swapmon$VERSION[$$] ${SWAPF} is not a valid swapfile."|$LOGGER
+		fi
+		$SED -I '' -n '$!p' "${SWAPLIST}"
+		SWAPCTLSK=$($SWAPCTL -sk)
+		SWAPTOTAL=${SWAPCTLSK#* }
+		SWAPTOTAL=${SWAPTOTAL% *}
+		SWAPUSAGE=$(( ${SWAPCTLSK##* } * 100 / $SWAPTOTAL ))
+	done
+}
+
+case "$1" in
+	start)
+		$0 -F <&- 2>&1 >/dev/null &
+		;;
+	stop)
+		if [ -s "${PIDFILE}" ]
+		then
+			PID=$(/bin/cat ${PIDFILE})
+			if ( /bin/ps -p $PID|grep -q $0 )
+			then	/bin/kill $PID
+			fi
+			$RM "${PIDFILE}"
+		fi
+		;;
+	-F)
+		echo $$ >"${PIDFILE}"
+		echo "swapmon$VERSION[$$] Writing pid $$ to pidfile ${PIDFILE}."|$LOGGER
+		cd / || exit 1
+		while [ -f "${PIDFILE}" ]
+		do	check_swap
+			sleep ${DELAY}
+		done
+		;;
+	'')
+		if [ -r "${LOCKF}" ]
+		then
+			echo "${LOCKF} exists"
+			exit 1;
+		else
+			echo $$ >"${LOCKF}"
+			LOGGER="|/bin/cat"
+			check_swap
+		fi
+		$RM -f "${LOCKF}"
+		;;
+	*)
+		echo "$* not supported"
+		;;
+esac
diff --git a/sysutils/swapmon/pkg-descr b/sysutils/swapmon/pkg-descr
new file mode 100644
index 00000000000..9d28ee66b09
--- /dev/null
+++ b/sysutils/swapmon/pkg-descr
@@ -0,0 +1,9 @@
+swapmon will check the current swapusage and if more than SWAP_HIGH per-
+cent of swapspace is in use it will create a new swapfile with a size of
+size of SWAP_STEP percent of the current swapspace and activate it.  If
+less than SWAP_LOW percent of swapspace is in use it will deactivate a
+previously added swapspace file and remove it.
+
+WWW: http://www.nagilum.net/swapmon/
+
+freebsd@nagilum.org