newvers: Add a builddir parameter

When reproducible builds are configured, we should use /usr/obj as the
canonical objdir.  Add a parameter to newvers.sh to ensure that build
metadata is reproducible.

Reviewed by:	emaste
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D50954

2 files changed, 7 insertions, 3 deletions

diff --git a/sys/conf/kern.post.mk b/sys/conf/kern.post.mk
index 1accd3fa8df4..bb3c7af82a4d 100644
--- a/sys/conf/kern.post.mk
+++ b/sys/conf/kern.post.mk
@@ -467,7 +467,7 @@ config.o env.o hints.o vers.o vnode_if.o:
 
 NEWVERS_ENV+= MAKE="${MAKE}"
 .if ${MK_REPRODUCIBLE_BUILD} != "no"
-NEWVERS_ARGS+= -R
+NEWVERS_ARGS+= -R -d ${PREFIX_OBJDIR}
 .endif
 vers.c: .NOMETA_CMP $S/conf/newvers.sh $S/sys/param.h ${SYSTEM_DEP:Nvers.*}
 	${NEWVERS_ENV} sh $S/conf/newvers.sh ${NEWVERS_ARGS} ${KERN_IDENT}
diff --git a/sys/conf/newvers.sh b/sys/conf/newvers.sh
index 66926805052c..8b60da95741e 100644
--- a/sys/conf/newvers.sh
+++ b/sys/conf/newvers.sh
@@ -110,14 +110,18 @@ COPYRIGHT="$COPYRIGHT
 
 # We expand include_metadata later since we may set it to the
 # future value of modified.
+builddir=$(pwd)
 include_metadata=yes
 modified=no
-while getopts crRvV: opt; do
+while getopts cd:rRvV: opt; do
 	case "$opt" in
 	c)
 		echo "$COPYRIGHT"
 		exit 0
 		;;
+	d)
+		builddir=$OPTARG
+		;;
 	r)
 		include_metadata=no
 		;;
@@ -187,7 +191,7 @@ fi
 touch version
 v=$(cat version)
 u=${USER:-root}
-d=$(pwd)
+d=$builddir
 h=${HOSTNAME:-$(hostname)}
 if [ -n "$SOURCE_DATE_EPOCH" ]; then
 	if ! t=$(date -ur $SOURCE_DATE_EPOCH 2>/dev/null); then