newvers.sh: add option to eliminate kernel build metadata

Build metadata (username, hostname, etc.) prevents the FreeBSD kernel
from building reproducibly. Add an option to disable inclusion of that
metadata but retain the release information and SVN/git VCS details.
See https://reproducible-builds.org/ for additional background.

Reviewed by:	bapt
Obtained from:	NetBSD
MFC after:	1 month
Sponsored by:	Reproducible Builds World Summit 2, Berlin
Differential Revision:	https://reviews.freebsd.org/D4347

diff --git a/sys/conf/newvers.sh b/sys/conf/newvers.sh
index 72e9ae60610abf2c75a8488992c5ab2df516ad8b..9e018f769f0e825764fd6b120bc147b6d57e774d 100644 (file)
--- a/sys/conf/newvers.sh
+++ b/sys/conf/newvers.sh
@@ -30,6 +30,14 @@
 #      @(#)newvers.sh  8.1 (Berkeley) 4/20/94
 # $FreeBSD$
 
+# Command line options:
+#
+#     -r               Reproducible build.  Do not embed directory names, user
+#                      names, time stamps or other dynamic information into
+#                      the outuput file.  This is intended to allow two builds
+#                      done at different times and even by different people on
+#                      different hosts to produce identical output.
+
 TYPE="FreeBSD"
 REVISION="12.0"
 BRANCH="CURRENT"
@@ -250,10 +258,28 @@ if [ -n "$hg_cmd" ] ; then
        fi
 fi
 
+include_metadata=true
+while getopts r opt; do
+       case "$opt" in
+       r)
+               include_metadata=
+               ;;
+       esac
+done
+shift $((OPTIND - 1))
+
+if [ -z "${include_metadata}" ]; then
+       VERINFO="${VERSION} ${svn}${git}${hg}${p4version}"
+       VERSTR="${VERINFO}\\n"
+else
+       VERINFO="${VERSION} #${v}${svn}${git}${hg}${p4version}: ${t}"
+       VERSTR="${VERINFO}\\n    ${u}@${h}:${d}\\n"
+fi
+
 cat << EOF > vers.c
 $COPYRIGHT
-#define SCCSSTR "@(#)${VERSION} #${v}${svn}${git}${hg}${p4version}: ${t}"
-#define VERSTR "${VERSION} #${v}${svn}${git}${hg}${p4version}: ${t}\\n    ${u}@${h}:${d}\\n"
+#define SCCSSTR "@(#)${VERINFO}"
+#define VERSTR "${VERSTR}"
 #define RELSTR "${RELEASE}"
 
 char sccs[sizeof(SCCSSTR) > 128 ? sizeof(SCCSSTR) : 128] = SCCSSTR;