3-way merge for /etc (mergemaster replacement)

5 files changed, 709 insertions, 0 deletions

diff --git a/sysutils/etcmerge/Makefile b/sysutils/etcmerge/Makefile
new file mode 100644
index 000000000000..1b22484e20e5
--- /dev/null
+++ b/sysutils/etcmerge/Makefile
@@ -0,0 +1,34 @@
+# New ports collection makefile for:		etcmerge
+# Date created:					05 July 2003
+# Whom:						eivind
+#
+# $FreeBSD$
+#
+# This port is self contained in the src directory.
+#
+
+PORTNAME=	etcmerge
+PORTVERSION=	0.1
+CATEGORIES=	sysutils textproc
+MASTER_SITES=	# none
+DISTFILES=	# none
+
+MAINTAINER=	eivind@FreeBSD.org
+COMMENT=	"Automatic 3-way merge of /etc updates"
+
+NO_BUILD=	yes
+NO_WRKSUBDIR=	yes
+NO_MAN=		yes
+
+SRC=		${.CURDIR}/src
+
+MAN8=		${PORTNAME}.8
+
+do-fetch:
+	@${DO_NADA}
+
+do-install:
+	@${INSTALL_SCRIPT} ${SRC}/${PORTNAME}.sh ${PREFIX}/sbin/${PORTNAME}
+	@${INSTALL_MAN} ${SRC}/${PORTNAME}.8 ${PREFIX}/man/man8
+
+.include <bsd.port.mk>
diff --git a/sysutils/etcmerge/pkg-descr b/sysutils/etcmerge/pkg-descr
new file mode 100644
index 000000000000..cb9c3b50c6fe
--- /dev/null
+++ b/sysutils/etcmerge/pkg-descr
@@ -0,0 +1,4 @@
+etcmerge is a tool for keeping /etc up to date when updating.
+The primary difference from mergemaster is that etcmerge
+requires much less manual work than mergemaster, due to the
+use of a three way merge.
diff --git a/sysutils/etcmerge/pkg-plist b/sysutils/etcmerge/pkg-plist
new file mode 100644
index 000000000000..d370acbd6f37
--- /dev/null
+++ b/sysutils/etcmerge/pkg-plist
@@ -0,0 +1 @@
+sbin/etcmerge
diff --git a/sysutils/etcmerge/src/etcmerge.8 b/sysutils/etcmerge/src/etcmerge.8
new file mode 100644
index 000000000000..37205c8080c1
--- /dev/null
+++ b/sysutils/etcmerge/src/etcmerge.8
@@ -0,0 +1,269 @@
+.\"-
+.\" Copyright (c) 2003 Eivind Eklund
+.\" 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
+.\"    in this position and unchanged.
+.\" 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.
+.\" 3. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
+.\"
+.\"	$FreeBSD$
+.\"
+.Dd July 5, 2003
+.Dt ETCMERGE 1
+.Sh NAME
+.Nm etcmerge
+.Nd 3-way merge of /etc with updates from /usr/src
+.Sh SYNOPSIS
+.Nm etcmerge
+.Cm init
+.Nm
+.Cm install
+.Sh DESCRIPTION
+.Pp
+WARNING: ETCMERGE HAS NOT UNDERGONE EXTENSIVE PRODUCTION USE, SO USE AT YOUR
+OWN RISK.
+Taking a backup of
+.Pa /etc
+before running it won't hurt.
+.Pp
+.Nm
+is a tool for keeping your
+.Pa /etc
+up to date as you update your system.
+It fills the same niche as
+.Xr mergemaster 8 ,
+with the primary difference being that
+.Nm
+requires much less manual work.
+This is because
+.Nm
+merges two sets of changes instead of two copies of etc:
+The changes you have done locally are merged with the changes done by
+.Fx .
+.Nm
+does this by tracking three instead of two copies of
+.Pa etc
+- the active
+.Pa /etc
+(the one you are running your system on), the new etc distributed from
+.Fx
+(generated from
+.Pa /usr/src
+by
+.Nm
+), and a reference copy of the etc that was originally distributed from
+.Fx
+and which you have changed to get the active
+.Pa /etc .
+.Pp
+The use of all three copies allow
+.Nm
+to find the two sets of changes - changes by you (the difference from
+reference to installed etc) and changes by
+.Fx
+(the difference from reference etc to new etc).
+.Pp
+A three way merge is usually fully automated - no user interaction is needed
+for the merge itself.
+However, sometimes conflicting changes have been made - you have done one
+change, and
+.Fx
+has done a different change to the same part of
+.Pa /etc .
+.Sh "ROUGH DESCRIPTION OF USE"
+.Pp
+First, ensure you have a copy of the /etc distributed by FreeBSD (BEFORE you or
+.Xr sysinstall 8
+started modifying it) stored in
+.Pa /var/db/etc .
+The easiest way to do this is to run
+.Xr mergemaster 8
+one last time, and copy
+.Pa /var/tmp/temproot/etc
+to
+.Pa /var/db/etc .
+.Pp
+When you have
+.Pa /var/db/etc
+initialized, start a merge with
+.Ic "etcmerge init"
+(as root).
+.Nm
+will run for a while, and start printing out information about what operations
+it does, prefixed with ETCMERGE:.
+When it is finished, it will print out a line saying which work directory it
+has worked in (by default, ${HOME}/etc-work/<date>).
+Change to this directory, and check if you have any .conflicts files there.
+If you do, check through them, and resolve the conflicts.
+The conflicts will be recorded in different ways depending on what kind of
+conflicts they are.
+Under the directory
+.Pa etc-merged
+you'll find a replacement for /etc, including both changes done by you and
+FreeBSD.
+Any files that have normal change conflicts (you and FreeBSD have made
+different changes) will have conflict markers ("<<<<<<<<", "=====" and
+">>>>>>>") indicating where the conflict is.
+See
+.Xr merge 1
+for details.
+The files with this kind of conflict will be listed in
+.Pa 7.conflicts .
+Other forms of conflicts will be listed in other .conflict files; see below
+for details if you get any of these.
+.Pp
+When you are finished with resolving conflicts, type
+.Ic "etcmerge install"
+to make the present
+.Pa etc-merged
+directory replace
+.Pa /etc ,
+and make
+.Pa etc-new
+(newly generated etc, based on the present
+.Pa /usr/src )
+the new reference etc.
+.Sh "INTERNAL DESCRIPTION"
+.Pp
+In order to do its work,
+.Nm
+divides the files it operate in into different classes, and do different
+operations depending on which class the files belong in.
+This division makes a difference for how each file is treated.
+The exact treatment of each class will be printed out by
+.Nm
+when you run it, along with how many files is in each class, and how many
+conflicts occur.
+Each conflict is registered in
+.Pa <class-number>.conflicts -
+e.g.
+.Pa 7.conflicts
+for conflicts in class 7 (3-way merged files).
+.Sh CLASSES
+.Pp
+The following table define what the class numbers refer to.
+The headings "Reference", "New", and "Active" refers to various copies of
+.Pa etc
+- the one generated from
+.Pa /usr/src
+(New), the one stored as a Reference copy (basically the one generated from
+.Pa /usr/src
+the last time you ran
+.Nm
+or the one distributed with the
+.Fx
+you installed), and the one presently Active (ie, the one stored in
+.Pa /etc
+when you run
+.Nm etcmerge ).
+.Bl -column -offset indent ".Sy Class" ".Sy Reference" "Reference" ".Sy Active"
+.It Sy Class Ta Sy Reference Ta Sy New Ta Sy Active
+.It Li 1 Ta Absent Ta Absent Ta Present
+.It Li 2 Ta Absent Ta Present Ta Absent
+.It Li 3 Ta Absent Ta Present Ta Present
+.It Li 4 Ta Present Ta Absent Ta Absent
+.It Li 5 Ta Present Ta Absent Ta Present
+.It Li 6 Ta Present Ta Present Ta Absent
+.It Li 7 Ta Present Ta Present Ta Present
+.El
+.Pp
+Depending on what class each file (and I'm talking flat files here) is in, it
+will be handled differently.
+(See separate description for handling of directories and special files.)
+The following table describes how each class of files are handled when there
+are no conflicts in the file.
+.Bl -column -offset indent ".Sy Class" ".Sy Reference" "Reference" ".Sy Active"
+.It Sy Class Ta Sy "File merge handling"
+.It Li 1 Ta "Copy from Active"
+.It Li 2 Ta "Copy from New"
+.It Li 3 Ta "Copy from New"
+.It Li 4 Ta "Drop file"
+.It Li 5 Ta "Drop file (store in conflict dir if diffs)"
+.It Li 6 Ta "Drop file (store in conflict dir)"
+.It Li 7 Ta "Do a 3-way merge between all variant, and store result in etc-merged"
+.El
+Depending on what class a file is in, conflicts will be detected differently,
+and handled differently.
+The below table detail how conflicts are detected and handled for each class.
+.Bl -column -offset indent ".Sy Class" ".Sy Reference" "Reference" ".Sy Active"
+.It Sy Class Ta Sy "File conflict handling"
+.It Li 1 Ta "Cannot be a conflict"
+.It Li 2 Ta "Cannot be a conflict"
+.It Li 3 Ta "If there are differences between New and Active, store a diff file in merged-changed."
+.It Li 4 Ta "Cannot be a conflict"
+.It Li 5 Ta "If there are differences between New and Active, store a diff file in merged-removed."
+.It Li 6 Ta "Store file in merged-conflicts, with a diff file if there are diffs between Reference and New"
+.It Li 7 Ta "Conflicts are indicated inside the file, using <<<<<<<<<, ======= and >>>>>>>>> as markers.  See merge(1)."
+.El
+Directories and special files are also handled by
+.Nm etcmerge .
+Empty directories and special files are handled by class (see the tables
+below).
+Directories with content is handled alongside files.
+When a file is copied over to the merged etc (the one
+.Nm
+generates), all prefix directories will be copied too, using permissions
+either from the active (if available) or the new
+.Pa etc .
+Ie, if
+.Nm
+decide to copy
+.Pa etc/ssh/ssh_config
+from
+.Pa /etc ,
+then
+.Pa merged-etc/ssh
+will get the same permissions as
+.Pa /etc/ssh .
+.Pp
+This table details how special files (symlinks, device nodes, pipes, etc) and
+empty directories are handled.
+.Nm
+does not look for conflicts for these, but just copies them as appropriate.
+.Bl -column -offset indent ".Sy Class" ".Sy Directory/special.file.handling"
+.It Sy Class Ta Sy "Directory/special file handling"
+.It Li 1 Ta "Copy from Active"
+.It Li 2 Ta "Copy from New"
+.It Li 3 Ta "Copy from Active"
+.It Li 4 Ta "Ignore dir/special file"
+.It Li 5 Ta "Ignore dir/special file"
+.It Li 6 Ta "Ignore dir/special file"
+.It Li 7 Ta "Copy from Active"
+.El
+.Sh "DIRECTORIES USED"
+.Pp
+.Bl -column -offset indent "Directory" "Description"
+.It Li "etc-merged" Ta "Merged etc directory, based on etc-new but customized with on your changes."
+.It Li "etc-new" Ta "New etc directory, as distributed by FreeBSD.  Created based on /usr/src."
+.It Li "classes" Ta "Data about what goes in what class"
+.It Li "merged-removed" Ta "Files that have been removed, along with .diff files if the active file was different from the reference file."
+.It Li "merged-changed" Ta "Files that have been replaced by the update, along with .diff files saying what changes this has resulted in."
+.It Li "merged-conflicts" Ta "Files that are present in new and reference, but
+not in the active etc.  If these are changed, a .diff is also stored here."
+.El
+.Sh REFERENCES
+.Pp
+.Xr mergemaster 8 ,
+.Xr merge 1 .
+.Sh AUTHOR
+.Pp
+Eivind Eklund <eivind@FreeBSD.org>
diff --git a/sysutils/etcmerge/src/etcmerge.sh b/sysutils/etcmerge/src/etcmerge.sh
new file mode 100644
index 000000000000..d5d8d4edcbab
--- /dev/null
+++ b/sysutils/etcmerge/src/etcmerge.sh
@@ -0,0 +1,401 @@
+#!/bin/sh
+# ex:ts=8
+# vim:sts=4:sw=4:tw=120
+#
+# etcmerge - a program to merge an old and a new copy of the FreeBSD /etc
+# directory
+#
+
+#
+# Exit on encountering an error or unknown variable
+#
+set -e -u
+
+usage() {
+    echo "Usage:" 1>&2
+    echo "  etcmerge [-d <workdir>] [-e <etcdir>] [-r <refdir>] [-s <srcdir>] \\" 1>&2
+    echo "               [init|install]" 1>&2
+    echo 1>&2
+    echo "    -d   Set work directory for merge.  Defaults to" 1>&2
+    echo "               ${HOME}/etc-work/$(date +%Y%m%d%H%M)" 1>&2
+    echo "    -e   Set etc directory to merge.  Defaults to /etc" 1>&2
+    echo "    -r   Reference copy of etc.  Defaults to /var/db/etc" 1>&2
+    echo "    -s   FreeBSD source directory.  Defaults to /usr/src" 1>&2
+    echo 1>&2
+    echo "  init:      Do full generation of a new etc directory, including merge from the" 1>&2
+    echo "             active etc." 1>&2
+    echo 1>&2
+    echo "  install:   Make the merged etc active, and the newly generated from source etc" 1>&2
+    echo "             the new reference.  This prepares for a new merge." 1>&2
+    echo 1>&2
+    echo 1>&2
+    echo "  IMPORTANT: Before running 'install', you should resolve any conflicts" 1>&2
+    echo "             reported." 1>&2
+    echo "             Any '.diff' files that are left in merged-* directories represent" 1>&2
+    echo "             changes that are LOST in the newly merged etc.  These should either" 1>&2
+    echo "             be hand-applied or deemed OK to loose." 1>&2
+}
+
+#
+# Where we store our work files
+#
+WORKDIR=${HOME}/etc-work/$(date +%Y%m%d%H%M)
+
+while getopts ":d:e:r:s:" ARGUMENT ; do
+    case "${ARGUMENT}" in
+	d) WORKDIR="${OPTARG}" ;;
+	e) ACTIVEETC="${OPTARG}" ;;
+	r) REFETC="${OPTARG}" ;;
+	s) USRSRC="${OPTARG}" ;;
+	*) usage; exit 1 ;;
+    esac
+done
+
+
+#
+# Where we store class files
+#
+CLASSDIR=${WORKDIR}/classes
+mkdir -p ${CLASSDIR}
+
+#
+# Where the new "root" is linked from
+#
+NEWROOT="${WORKDIR}/new-base"
+
+#
+# Where the new etc is fetched from
+#
+NEWETC="${WORKDIR}/etc-new"
+
+#
+# Where we store our backup copy of an unmodified etc
+#
+REFETC=/var/db/etc
+
+#
+# Where the active copy of etc is stored
+#
+ACTIVEETC=/etc
+
+#
+# Where does our main merged tree go?
+#
+MERGEDETC=${WORKDIR}/etc-merged
+
+#
+# Where is our source code?
+#
+USRSRC=/usr/src
+
+#
+# How do we use CPIO for extract?
+#
+CPIO_EXTRACT="cpio -i -d -u --quiet"
+
+#
+# How do we use CPIO for archiving?
+#
+CPIO_ARCHIVE="cpio -o -H crc --quiet"
+
+#
+# Show number of conflicts for a particular class
+#
+conflictshow() {
+    id=$1
+    if [ -s "${WORKDIR}/${id}.conflicts" ]; then
+	echo "ETCMERGE: >>>>"
+	echo "ETCMERGE: >>>> Class ${id}: $(cat "${WORKDIR}/${id}.conflicts" | wc -l) conflict(s)"
+    fi
+}
+
+case "$1" in
+    init)    ;;
+    install)
+	if ! [ -d "etc-merged" -a "etc-new" ]; then
+	    echo "install attempted without standing in work directory" 1>&2
+	    echo "cd to work directory (by default under ${HOME}/etc-work/) and try again." 1>&2
+	    exit 1
+	fi
+	for i in $(cat *.conflicts 2> /dev/null); do
+	    if egrep -q '^(<<<<<<< |=======$|>>>>>>> )' etc-merged/$i; then
+		echo "Unresolved conflicts in ${i}" 1>&2
+		exit 1
+	    fi
+	done
+	tmpetc=/etc.$(date +%Y%m%d)
+	# XXX The entire set of operations below should be transactional.
+	#     This could be achieved by doing the updates as a series of
+	#     ln operations, then syncing, then removing the extra files,
+	#     and ending with removing the temporary directories, at each
+	#     phase recording what phase we are in.
+	#
+	#     Instead, the system now just prays that error does not
+	#     happen in the tiny section where it does the actual rename
+	#     operations, and syncs around this.  This is probably still
+	#     quicker than doing it the safe way.
+	#
+	# FIXME Should check for existance beforehand
+	mv etc-merged ${tmpetc}
+	mv etc-new ${REFETC}.etcmerge
+	fsync /
+	fsync ${REFETC}.etcmerge
+	fsync /var/db
+	# Should get everything to disk, one would hope.
+	sync && sleep 0.5 && sync && sleep 0.5 && sync && sleep 0.5
+	mv /etc/ /etc.etcmergeold
+	mv ${tmpetc} /etc
+	fsync /
+	mv ${REFETC} ${REFETC}.etcmergeold
+	mv ${REFETC}.etcmerge ${REFETC}
+	fsync /var/db
+	# Do a sync that can keep running after the program exists.
+	sync && sync && sync
+	echo "Install done - removing copies of old /etc and old reference." 1>&2
+	rm -rf /etc.etcmergeold ${REFETC}.etcmergeold
+	echo "Done." 1>&2
+	exit 0
+	;;
+    *)
+      usage
+      exit 1
+      ;;
+esac
+
+
+echo "ETCMERGE: >>> Creating new etc data from ${USRSRC}"
+#
+# XXX Make sure we have all needed users and groups before this
+#
+if ! (mkdir -p "${NEWROOT}" && \
+	cd ${USRSRC}/etc && \
+	make DESTDIR="${NEWROOT}" distrib-dirs && \
+	make DESTDIR="${NEWROOT}" distribution && \
+	mv ${NEWROOT}/etc ${NEWETC}); then
+    echo "Unable to create new etc directory" 1>& 2
+    echo "MERGE FAILED" 1>&2
+    exit 1
+else
+    rm -rf ${NEWROOT} 2> /dev/null || (chflags -R noschg ${NEWROOT} && rm -rf ${NEWROOT}) || \
+    (echo "Unable to clean out temp root" 1>&2; echo "MERGE FAILED" 1>&2; exit 1)
+fi
+
+echo "ETCMERGE: >>> Finding classes of files"
+echo "ETCMERGE: >>> Working from"
+echo "ETCMERGE: >>>     Active:    ${ACTIVEETC}"
+echo "ETCMERGE: >>>     Reference: ${REFETC}"
+echo "ETCMERGE: >>>     New:       ${NEWETC}"
+
+#
+# Find list of new files and list of old (reference) files
+#
+cd $WORKDIR
+(cd "${NEWETC}"    && find . -type f -print | sort > ${CLASSDIR}/newetc.files)
+(cd "${NEWETC}"    && find . -type d -links 2 -print | sort > ${CLASSDIR}/newetc.emptydirs)
+(cd "${NEWETC}"    && find . \! \( -type d -or -type f \) -print | sort > ${CLASSDIR}/newetc.others)
+(cd "${REFETC}"    && find . -type f -print | sort > ${CLASSDIR}/refetc.files)
+(cd "${REFETC}"    && find . -type d -links 2 -print | sort > ${CLASSDIR}/refetc.emptydirs)
+(cd "${REFETC}"    && find . \! \( -type d -or -type f \) -print | sort > ${CLASSDIR}/refetc.others)
+(cd "${ACTIVEETC}" && find . -type f -print | sort > ${CLASSDIR}/activeetc.files)
+(cd "${ACTIVEETC}"    && find . -type d -links 2 -print | sort > ${CLASSDIR}/activeetc.emptydirs)
+(cd "${ACTIVEETC}"    && find . \! \( -type d -or -type f \) -print | sort > ${CLASSDIR}/activeetc.others)
+
+#
+# Generate lists of differences on a file level, which effectively divides all
+# files into classes:
+#
+# Id	Ref	New	Active		Action
+#  0    Absent	Absent	Absent		(Irrelevant case)
+#  1	Absent	Absent	Present		Copy file over, with directory if necessary
+#  2	Absent	Present	Absent		Copy file over, with directory if necessary	
+#  3	Absent	Present	Present		Store NEW file
+#					If there are differences:
+#						Store diff 
+#						Add to conflict list
+#  4	Present	Absent	Absent		Ignore file
+#  5	Present	Absent	Present		No differences: Ignore files
+#					With differences: Store in conflict
+#						directory, with separate diff file
+#  6	Present Present Absent		Store in conflict directory
+#  7	Present Present Present		Do a 3-way merge, with directory if
+#  						necessary.
+cd ${CLASSDIR}
+for extension in files emptydirs others; do
+    cat refetc.${extension} newetc.${extension} activeetc.${extension} | sort -u > alletc.${extension}
+    cat refetc.${extension} newetc.${extension} | sort | uniq -d | cat - activeetc.${extension} | sort | uniq -d > ${CLASSDIR}/7.${extension}
+    cat alletc.${extension} refetc.${extension} newetc.${extension}	| sort | uniq -u > ${CLASSDIR}/1.${extension}
+    cat alletc.${extension} refetc.${extension} activeetc.${extension}	| sort | uniq -u > ${CLASSDIR}/2.${extension}
+    cat alletc.${extension} newetc.${extension} activeetc.${extension}	| sort | uniq -u > ${CLASSDIR}/4.${extension}
+    cat newetc.${extension} activeetc.${extension}		| sort | uniq -d | cat - refetc.${extension} refetc.${extension} | sort | uniq -u > ${CLASSDIR}/3.${extension}
+    cat refetc.${extension} activeetc.${extension}		| sort | uniq -d | cat - newetc.${extension} newetc.${extension} | sort | uniq -u > ${CLASSDIR}/5.${extension}
+    cat refetc.${extension} newetc.${extension}			| sort | uniq -d | cat - activeetc.${extension} activeetc.${extension} | sort | uniq -u > ${CLASSDIR}/6.${extension}
+done
+
+for i in 1 2 3 4 5 6 7; do
+    echo "ETCMERGE: >>>> Class ${i}: $(cat ${CLASSDIR}/$i.files | wc -l) files, $(cat ${CLASSDIR}/$i.emptydirs | wc -l) empty dirs, $(cat ${CLASSDIR}/$i.others | wc -l) others"
+done
+
+#
+# Create directory for merged data
+#
+mkdir ${MERGEDETC}
+
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>> Handling class 7 files - present everywhere"
+echo "ETCMERGE: >>>> Files are handled as an ascii 3-way merge."
+echo "ETCMERGE: >>>> Non-files get copied from the ACTIVE etc dir."
+
+#
+# Class 7 - present everywhere.  Create a merged directory tree.
+#
+cd ${MERGEDETC}
+(cd ${ACTIVEETC} && cat ${CLASSDIR}/7.files ${CLASSDIR}/7.emptydirs ${CLASSDIR}/7.others | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+for i in $(cat ${CLASSDIR}/7.files); do
+    if ! merge -q $i ${REFETC}/$i ${NEWETC}/$i; then
+	echo ${i} >> ${WORKDIR}/7.conflicts
+    fi
+done
+conflictshow 7
+
+#
+# Class 1 - only present in active directory.  Copy over.
+#
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>> Handling class 1 - only present in active directory"
+echo "ETCMERGE: >>>> Both files and non-files get copied."
+echo "ETCMERGE: >>>"
+cd ${MERGEDETC}
+(cd ${ACTIVEETC} && cat ${CLASSDIR}/1.files ${CLASSDIR}/1.emptydirs ${CLASSDIR}/1.others | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+
+#
+# Class 2 - only present in new directory.  Copy over.
+#
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>> Handling class 2 - only present in new directory"
+echo "ETCMERGE: >>>> Both files and non-files get copied."
+echo "ETCMERGE: >>>"
+cd ${MERGEDETC}
+(cd ${NEWETC} && cat ${CLASSDIR}/2.files ${CLASSDIR}/2.emptydirs ${CLASSDIR}/2.others | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+
+#
+# Class 3 - present in new and active directory, but not ref.
+# Use the active directory permissions, but the new file.
+# If the files differ, store filename in 3.conflicts and the active version and a diff in merged-changed.
+#
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>>> Handling class 3 - present in new and active directory only"
+echo "ETCMERGE: >>>> Files with differences get a copy of NEW file in both"
+echo "ETCMERGE: >>>> etc-merged and merged-changed, with a .diff from the NEW to"
+echo "ETCMERGE: >>>> the ACTIVE file in merged-changed."
+echo "ETCMERGE: >>>> Non-files are fetched from the ACTIVE directory."
+echo "ETCMERGE: >>>"
+cd ${MERGEDETC}
+(cd ${ACTIVEETC} && cat ${CLASSDIR}/3.files ${CLASSDIR}/3.emptydirs ${CLASSDIR}/3.others | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+(cd ${NEWETC} && cat ${CLASSDIR}/3.files | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+for i in $(cat ${CLASSDIR}/3.files); do
+    if ! diff -q ${ACTIVEETC}/$i ${REFETC}/$i > /dev/null; then
+	# Files differ
+	echo $i >> ${WORKDIR}/3.conflicts
+    fi
+done
+conflictshow 3
+#
+# Handle differing files (if any)
+#
+if [ -s ${WORKDIR}/3.conflicts ]; then
+    mkdir -p ${WORKDIR}/merged-changed
+    cd ${WORKDIR}/merged-changed
+    (cd ${ACTIVEETC} && cat ${WORKDIR}/3.conflicts | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+    for i in $(cat ${WORKDIR}/3.conflicts); do
+	diff -u ${REFETC}/$i $i > $i.diff
+    done
+fi
+
+#
+# Class 4 - present in ref, removed in new and active
+#
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>> Handling class 4 - present in reference only"
+echo "ETCMERGE: >>>> A copy of each file is stored in merged-removed."
+echo "ETCMERGE: >>>> Non-files get dropped."
+echo "ETCMERGE: >>>"
+if [ -s ${CLASSDIR}/4.files ]; then
+    mkdir -p ${WORKDIR}/merged-removed
+    cd ${WORKDIR}/merged-removed
+    (cd ${REFETC} && cat ${CLASSDIR}/4.files | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+fi
+
+#
+# Class 5 - present in ref and active, removed in new
+#
+# For all files where the active is different from the reference, create a copy in merged-removed, with a .diff that
+# shows what the differences are.
+# For all unchanged files, just copy them over.
+#
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>> Handling class 5 - present in reference and active only"
+echo "ETCMERGE: >>>> A copy of each ACTIVE file is stored in merged-removed."
+echo "ETCMERGE: >>>> If there is a difference between the ACTIVE and the"
+echo "ETCMERGE: >>>> REFERENCE file, a diff from REFERENCE to ACTIVE gets"
+echo "ETCMERGE: >>>> stored in merged-removed/"
+echo "ETCMERGE: >>>> Non-files get dropped."
+echo "ETCMERGE: >>>"
+if [ -s ${CLASSDIR}/5.files ]; then
+    mkdir -p ${WORKDIR}/merged-removed
+    cd ${WORKDIR}/merged-removed
+    (cd ${ACTIVEETC} && cat ${CLASSDIR}/5.files | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+    for i in $(cat ${CLASSDIR}/5.files); do
+	if ! diff -q ${ACTIVEETC}/$i ${REFETC}/$i > /dev/null; then
+	    # Files differ
+	    echo $i >> ${WORKDIR}/5.conflicts
+	    diff -u ${REFETC}/$i ${ACTIVEETC}/$i > $i.diff
+	fi
+    done
+fi
+conflictshow 5
+
+#
+# Class 6 - present in ref and new, but removed in active
+# Files are copied from new to merged-conflicts, and if the files differ, the filename is added to 6.conflicts, 
+# and a .diff file with the changes that are lost is stored alongside the file.
+#
+echo "ETCMERGE: >>>"
+echo "ETCMERGE: >>> Handling class 6 - present in reference and new only"
+echo "ETCMERGE: >>>> A copy of the NEW version of each file is stored in"
+echo "ETCMERGE: >>>> merged-conflicts/"
+echo "ETCMERGE: >>>> If there are differences the REFERENCE and NEW file,"
+echo "ETCMERGE: >>>> a .diff file with these is also stored."
+echo "ETCMERGE: >>>> Non-files get dropped."
+echo "ETCMERGE: >>>"
+if [ -s ${CLASSDIR}/6.files ]; then
+    mkdir ${WORKDIR}/merged-conflicts
+    cd ${WORKDIR}/merged-conflicts
+    (cd ${NEWETC} && cat ${CLASSDIR}/6.files | ${CPIO_ARCHIVE}) | ${CPIO_EXTRACT}
+    for i in $(cat ${CLASSDIR}/6.files); do
+	if ! diff -q $i ${REFETC}/$i > /dev/null; then
+	    # Files differ
+	    echo $i >> ${WORKDIR}/6.conflicts
+	    diff -u ${REFETC}/$i $i > $i.diff
+	fi
+    done
+fi
+conflictshow 6
+
+cat <<EOM
+
+Directories (only present if they would have contents)
+    etc-merged	      Replaced etc/ directory, ready for use (potentially after
+			conflict resolution)
+    etc-new	      New etc, generated from ${USRSRC}, and used to generate
+			etc-merged.
+    merged-removed    Files that have been removed, along with .diff files if
+			the active file was different from the reference file.
+    merged-changed    Files that have been replaced by the update, along with
+			.diff files saying what changes this has resulted in.
+    merged-conflicts  Files that are present in new and reference, but not in
+			the active etc.  If these are changed, a .diff is
+			also stored here.
+    classes	      Internal overview of what files belong to what classes
+
+Work directory: ${WORKDIR}
+EOM