#!/bin/sh
#
# Copyright (c) 2000-2001,2003 Silicon Graphics, Inc.  All Rights Reserved.
# 
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
# 
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.
# 
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#
# Rebuild the PMNS, handling assorted errors
#

# Note. has to be run from where the PMNS files are installed as local
#       file names (not full paths) are used
#

# source the PCP configuration environment variables
. $PCP_DIR/etc/pcp.env

tmp=`mktemp -d ./pmns_rebuild.XXXXXXXXX` || exit 1
status=1

$PCP_SHARE_DIR/lib/lockpmns root
trap "$PCP_SHARE_DIR/lib/unlockpmns root; rm -rf $tmp; exit \$status" 0 1 2 3 15

_trace()
{
    if $silent
    then
	:
    else
	if $nochanges
	then
	    echo "$*"
	else
	    echo "$*" >>$tmp/trace
	fi
    fi
}

_trace_file()
{
    if $silent
    then
	:
    else
	if $nochanges
	then
	    cat $1
	else
	    cat $1 >>$tmp/trace
	fi
    fi
}

_syslog()
{
    $PCP_SYSLOG_PROG -p user.alert -t PCP "$*"
    _trace "$*"
}

_die()
{
    [ -f $tmp/trace ] && cat $tmp/trace
    rm -f root.new
    exit
}

prog=`basename $0`
debug=false
skip_pmda_check=false
nochanges=false
root=root
root_updated=false
update=false
verbose=""
silent=false

_usage()
{
    _trace "Usage: Rebuild [-nsuv]"
    _trace "Options:"
    _trace "  -o    old behaviour, do not check PMDAs in pmcd.conf"
    _trace "  -n    dry run, show me what would be done"
    _trace "  -s    silent, exit status says it all"
    _trace "  -u    once only upgrade processing for a new PCP version"
    _trace "  -v    verbose, for the paranoid"
}

# Fixup "root" after PCP upgrade
#
_upgrade_root()
{
    [ ! -f root ] && return
    _trace "Rebuild: PCP upgrade processing for \"root\" PMNS changes ..."
    $nochanges && _trace "+ cull root_* names from PMNS ... <root >$tmp/root"

    # Cull root to remove all metrics from root_* files, so only metrics
    # for optional PMDAs remain

    # If there are deprecated top-level names (below "root") that are
    # no longer in a root_* file, add them here ...
    EXCLUDE="pagebuf origin"
    if [ "$PCP_PLATFORM" = linux ]
    then
	# If we're on Linux and the proc PMDA is _not_ included in
	# the pmcd configuration file, add the top-level metrics
	# that migrated from the linux PMDA to the proc PMDA
	#
	if [ -f $PCP_PMCDCONF_PATH ]
	then
	    if grep '^proc[ 	]' $PCP_PMCDCONF_PATH >/dev/null
	    then
		# proc PMDA is installed
		#
		:
	    else
		EXCLUDE="$EXCLUDE proc cgroup"
	    fi
	else
	    EXCLUDE="$EXCLUDE proc cgroup"
	fi
    else
	EXCLUDE="$EXCLUDE proc cgroup"
    fi

    # now gather top-level names from root_* files
    #
    if [ "`echo root_*`" != "root_*" ]
    then
	EXCLUDE_TMP=`for file in root_*
	do
	    $PCP_AWK_PROG <$file '
$1 == "}"			{ exit }
in_root==1			{ printf "%s ",$1 }
$1 == "root" && $2 == "{"	{ in_root = 1 }'
done`
	EXCLUDE="$EXCLUDE $EXCLUDE_TMP"
    fi

    if [ ! -z "$verbose" -a ! -z "$EXCLUDE" ]
    then
	_trace "Exclude these top-level names ..."
	_trace "`echo $EXCLUDE | fmt | sed -e 's/^/    /'`"
    fi

    $PCP_AWK_PROG <root >$tmp/root '
BEGIN	{   # exclude these top-level names and all their descendents
	    #
	    n = split("'"$EXCLUDE"'", e)
	    for (i=1; i <= n; i++) {
		not_in_root[e[i]] = 1
	    }

	    in_root = 0
	    skip = 0
	}
$1 == "root" && $2 == "{"	{ in_root = 1 }
$1 == "}"			{ in_root = 0 }
in_root				{ if (!($1 in not_in_root)) print
				  next
				}
$2 == "{"			{ n = split($1, name, ".")
			          if (n > 0 && name[1] in not_in_root)
				    skip = 1
				}
skip && $1 == "}"		{ skip = 0; next }
skip				{ next }
				{ print }'
    if cmp -s root $tmp/root >/dev/null 2>&1
    then
	# no changes ... already been here?
	:
    else
	# we will usually end up here
	root=$tmp/root
	root_updated=true
    fi
}

while getopts dnousv\? c
do
    case $c
    in
	d)	echo "$prog: Warning: -d deprecated, duplicate PMNS names allowed by default"
		;;
	o)	skip_pmda_check=true
		;;
	n)	nochanges=true
		echo "$prog: Warning: dry run, no changes will be made"
		;;
	u)	update=true
		;;
	s)	silent=true
		;;
	v)	verbose="-v"
		;;
	\?)	_usage
		status=0
		_die
		;;
    esac
done
shift `expr $OPTIND - 1`

# some preliminary checks
#
for file in $PCP_BINADM_DIR/pmnsmerge
do
    if [ ! -x $file ]
    then
	_syslog "$prog: $file is missing. Cannot proceed."
	_die
    fi
done

# remove all trace of old binary pmns (not used in PCP 3.6 or later)
#
rm -f root.bin

here=`pwd`
_trace "Rebuilding the Performance Metrics Name Space (PMNS) in $here ..."

if [ $# -ne 0 ]
then
    _usage
    _die
fi

if $nochanges
then
    CP="_trace + cp"
    MV="_trace + mv"
    LN="_trace + ln"
    RM="_trace + rm"
    PMNSMERGE="_trace + pmnsmerge ..."
else
    CP=cp
    MV=mv
    LN=ln
    RM=rm
    PMNSMERGE=

    if [ ! -w `pwd` ]
    then
	_syslog "$prog: cannot write in directory `pwd`, script should be run as \"root\"?"
	_die
    fi

    if [ -f root -a -s root ]
    then
	# root exists and is not empty, use as is
	:
    else
	# missing or empty root, create a new skeletal one
    	echo "root {" >root
    	echo "}" >>root
	chmod 644 root
    fi

    if [ ! -w root ]
    then
	_syslog "$prog: cannot write file \"root\" in directory `pwd`, script should be run as \"root\"?"
	_die
    fi
fi

if $update
then
    # PCP upgrade fix ups
    #
    _upgrade_root
fi

if [ -f $root ]
then
    haveroot=true
else
    haveroot=false
    if $nochanges
    then
	_trace "+ create empty root PMNS ..."
    else
	root=$tmp/root
	cat <<EOFEOF >$root
root {
}
EOFEOF
    fi
fi

# Merge $root and root_* to produce the new root, subject to the
# constraint that the corresponding PMDA is configured in pmcd.conf.
#
# For root_foo, we assume the corresponding PMDA is called foo in
# pmcd.conf ... if this is not the case, add an entry for the
# initialization of map[] in the awk script below.
#
# Each root_* file should be a complete namespace,
# i.e. it should include an entry for root.
#
echo >$tmp/mergelist
if [ "`echo root_*`" != "root_*" ]
then
    ls -1 root_* \
    | while read root_file
    do
	pmda=`echo "$root_file" \
	      | sed -e 's/root_//' \
	      | $PCP_AWK_PROG '
BEGIN	{ map["root_web"] = "-"	# historical old file, not present anymore
				# "-" means skip this one
	  # map["foo"] = "bar"	# example to where the PMDA bar populates
				# metrics defined in root_foo
        }
	{ if (map[$1] == "")	{ print $1; next }	# no mapping
	  if (map[$1] == "-")	{ next }		# omit
	  			{ print map[$1]; next }
	}'`
	if $skip_pmda_check \
	   || grep "^$pmda[ 	]" $PCP_PMCDCONF_PATH >/dev/null 2>&1
	then
	    # good to go, skipping check or PMDA is in pmcd.conf
	    #
	    echo "$root_file" >>$tmp/mergelist
	elif [ ! -z "$verbose" ]
	then
	    echo "Warning: skipping root_$pmda as $pmda PMDA is not in pmcd.conf"
	fi
    done
    mergelist="`cat $tmp/mergelist`"
fi

_trace "$prog: merging the following PMNS files: "
_trace $root $mergelist | fmt | sed -e 's/^/    /'

rm -f root.new
eval $PMNSMERGE
$PCP_BINADM_DIR/pmnsmerge $verbose $root $mergelist root.new >$tmp/out 2>&1

if [ $? != 0 ]
then
    cat $tmp/out
    _syslog "$prog: pmnsmerge failed"
    _trace "         \"root\" has not been changed."
    _die
fi

# Multiple Rebuilds in succession should be a no-op.
#
if [ -f root ]
then
    pminfo -m -n root 2>/dev/null | sort >$tmp/list.old
fi
if [ ! -s $tmp/list.old ]
then
    pminfo -m -n $root 2>/dev/null | sort >$tmp/list.old
fi
pminfo -m -n root.new | sort >$tmp/list.new
if cmp -s $tmp/list.old $tmp/list.new > /dev/null 2>&1
then
    [ ! -f root ] && eval $MV root.new root
    _trace "$prog: PMNS is unchanged."
else
    # Install the new root
    #
    [ ! -z "$verbose" ] && _trace_file $tmp/out
    if $haveroot
    then
	_trace "$prog: PMNS \"$here/root\" updated."
	_trace "... previous version saved as \"$here/root.prev\""
	eval $MV root root.prev
    else
	_trace "$prog: new PMNS \"$here/root\" created."
    fi
    eval $MV root.new root

    # signal pmcd if it is running
    #
    pminfo -v pmcd.version >/dev/null 2>&1 && pmsignal -a -s HUP pmcd

    if [ ! -z "$verbose" ] && $haveroot
    then
	_trace "+ PMNS differences ..."
	diff -c $tmp/list.old $tmp/list.new >$tmp/diff
	_trace_file $tmp/diff
	_trace
	_trace "+ root differences ..."
	diff -c root.prev root >$tmp/diff
	_trace_file $tmp/diff
    fi
fi
rm -f root.new

# remake stdpmid
#
[ -f Make.stdpmid ] && ./Make.stdpmid

[ X"$verbose" = X-v -a -f $tmp/trace ] && cat $tmp/trace

status=0
exit