MFC r303784, r303785, r305620:

r303784:
etcupdate: directly use diff3(1) instead of merge(1)

During the last attempt to rmeove GNU rcs, 2 blockers were spotted:
We need an ident(1) and etcupdate(8) uses merge(1).

Now nothing should prevent to remove rcs from base

Reviewed by:	jhb
Differential Revision:	https://reviews.freebsd.org/D7401

r303785:
always install etcupdate

Now that etcupdate does not depend on rcs anymore there is no need to
conditionnally install it

r305620: (by vangyzen )
etcupdate: preserve the metadata of the destination file

When using diff3 to perform a three-way merge, etcupdate lost the destination
file's metadata. The metadata from the temporary file were used instead.
This was unpleasant for rc.d scripts, which require execute permission.
Use "cat >" to overwrite the destination file's contents while preserving its
metadata.

Reviewed by:	bapt
Sponsored by:	Dell Technologies
Differential Revision:	https://reviews.freebsd.org/D7817

2 files changed, 12 insertions, 8 deletions

diff --git a/usr.sbin/Makefile b/usr.sbin/Makefile
index c2b0b7c..67499a1 100644
--- a/usr.sbin/Makefile
+++ b/usr.sbin/Makefile
@@ -25,6 +25,7 @@ SUBDIR=	adduser \
 	digictl \
 	diskinfo \
 	dumpcis \
+	etcupdate \
 	extattr \
 	extattrctl \
 	fifolog \
@@ -188,7 +189,6 @@ SUBDIR.${MK_QUOTAS}+=	edquota
 SUBDIR.${MK_QUOTAS}+=	quotaon
 SUBDIR.${MK_QUOTAS}+=	repquota
 SUBDIR.${MK_RCMDS}+=	rwhod
-SUBDIR.${MK_RCS}+=	etcupdate
 SUBDIR.${MK_SENDMAIL}+=	editmap
 SUBDIR.${MK_SENDMAIL}+=	mailstats
 SUBDIR.${MK_SENDMAIL}+=	makemap
diff --git a/usr.sbin/etcupdate/etcupdate.sh b/usr.sbin/etcupdate/etcupdate.sh
index bb12d36..2b4c145 100755
--- a/usr.sbin/etcupdate/etcupdate.sh
+++ b/usr.sbin/etcupdate/etcupdate.sh
@@ -814,15 +814,19 @@ merge_file()
 	local res
 
 	# Try the merge to see if there is a conflict.
-	merge -q -p ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1 >/dev/null 2>&3
+	diff3 -E -m ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1 > /dev/null 2>&3
 	res=$?
 	case $res in
 		0)
 			# No conflicts, so just redo the merge to the
 			# real file.
-			log "merge ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1"
+			log "diff3 -E -m ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1"
 			if [ -z "$dryrun" ]; then
-				merge ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1
+				temp=$(mktemp -t etcupdate)
+				diff3 -E -m ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1 > ${temp}
+				# Use "cat >" to preserve metadata.
+				cat ${temp} > ${DESTDIR}$1
+				rm -f ${temp}
 			fi
 			post_install_file $1
 			echo "  M $1"
@@ -832,10 +836,10 @@ merge_file()
 			# the conflicts directory.
 			if [ -z "$dryrun" ]; then
 				install_dirs $NEWTREE $CONFLICTS $1
-				log "cp -Rp ${DESTDIR}$1 ${CONFLICTS}$1"
-				cp -Rp ${DESTDIR}$1 ${CONFLICTS}$1 >&3 2>&1
-				merge -A -q -L "yours" -L "original" -L "new" \
-				    ${CONFLICTS}$1 ${OLDTREE}$1 ${NEWTREE}$1
+				log "diff3 -m -A ${DESTDIR}$1 ${CONFLICTS}$1"
+				diff3 -m -A -L "yours" -L "original" -L "new" \
+				    ${DESTDIR}$1 ${OLDTREE}$1 ${NEWTREE}$1 > \
+				    ${CONFLICTS}$1
 			fi
 			echo "  C $1"
 			;;