usermem

早期freebsd实现

: This shell script snoops around to find the maximum amount of available
: user memory.  These variables need to be set only if there is no
: /usr/adm/messages.  KMEM, UNIX, and CLICKSIZE can be set on the command
: line, if desired, e.g. UNIX=/unix
KMEM=/dev/kmem		# User needs read access to KMEM
UNIX=
# VAX			CLICKSIZE=512,	UNIX=/vmunix
# PDP-11		CLICKSIZE=64,	UNIX=/unix
# CADLINC 68000		CLICKSIZE=4096,	UNIX=/unix
# Perkin-Elmer 3205	CLICKSIZE=4096,	UNIX=/edition7
# Perkin-Elmer all others, CLICKSIZE=2048, UNIX=/edition7
CLICKSIZE=512
eval $*

SIZE=0
if test -r /usr/adm/messages	# probably the most transportable
then
    SIZE=`grep avail /usr/adm/messages | sed -n '$s/.*[ 	]//p'`
fi

if test 0$SIZE -le 0		# no SIZE in /usr/adm/messages
then
    if test -r $KMEM		# Readable KMEM
    then
	if test -n "$UNIX"
	then
	    : User must have specified it already.
	elif test -r /vmunix
	then
	    UNIX=/vmunix
	    CLICKSIZE=512	# Probably VAX
	elif test -r /edition7
	then
	    UNIX=/edition7
	    CLICKSIZE=2048	# Perkin-Elmer: change to 4096 on a 3205
	elif test -r /unix
	then
	    UNIX=/unix		# Could be anything
	fi
	if test -n "$UNIX"
	then
	    SIZE=`echo maxmem/D | adb $UNIX $KMEM | sed -n '$s/.*[ 	]//p'`
	    if test 0$SIZE -le 0
	    then
		SIZE=`echo physmem/D | adb $UNIX $KMEM | sed -n '$s/.*[ 	]//p'`
	    fi
	    SIZE=`expr 0$SIZE '*' $CLICKSIZE`
	fi
    fi
fi

case $UNIX in
    /vmunix)		# Assume 4.2bsd: check for resource limits
	MAXSIZE=`csh -c limit | awk 'BEGIN	{ MAXSIZE = 1000000 }
/datasize|memoryuse/ && NF == 3	{ if ($2 < MAXSIZE) MAXSIZE = $2 }
END	{ print MAXSIZE * 1000 }'`
	if test $MAXSIZE -lt $SIZE
	then
	    SIZE=$MAXSIZE
	fi
	;;
esac

if test 0$SIZE -le 0
then
    echo 0;exit 1
else
    echo $SIZE
fi