newvers.sh: add options to eliminate kernel build metadata

MFC r310112, r310114, r310273, r310279

r310112: 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.

r310114: newvers.sh: correct typo in comment

r310273: newvers.sh: add -R option to include metadata only for
         unmodified src tree

r310279: newvers.sh: consider as modified SVN mixed revision and other cases

The newvers -R option is intended to include build metadata (e.g. user,
host, time) if the build is from an unmodified VCS tree. For subversion
it considered a trailing 'M' as an indication of a modified tree, and
any other version string as modified.

Also include mixed revision checkouts (e.g. 123:126), switched (123S)
and partial (123P) working copies as modified: the revision number is
insufficient to uniquely determine which source was used for the build.

1 files changed, 51 insertions, 5 deletions

diff --git a/sys/conf/newvers.sh b/sys/conf/newvers.sh
index 0d5f795..fa05d7d 100644
--- a/sys/conf/newvers.sh
+++ b/sys/conf/newvers.sh
@@ -30,6 +30,18 @@
 #	@(#)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 output file.  This is intended to allow two builds
+#                      done at different times and even by different people on
+#                      different hosts to produce identical output.
+#
+#     -R               Reproducible build if the tree represents an unmodified
+#                      checkout from a version control system.  Metadata is
+#                      included if the tree is modified.
+
 TYPE="FreeBSD"
 REVISION="11.0"
 BRANCH="STABLE"
@@ -163,8 +175,16 @@ fi
 if [ -n "$svnversion" ] ; then
 	svn=`cd ${SYSDIR} && $svnversion 2>/dev/null`
 	case "$svn" in
-	[0-9]*)	svn=" r${svn}" ;;
-	*)	unset svn ;;
+	[0-9]*[MSP]|*:*)
+		svn=" r${svn}"
+		modified=true
+		;;
+	[0-9]*)
+		svn=" r${svn}"
+		;;
+	*)
+		unset svn
+		;;
 	esac
 fi
 
@@ -196,6 +216,7 @@ if [ -n "$git_cmd" ] ; then
 	if $git_cmd --work-tree=${SYSDIR}/.. diff-index \
 	    --name-only HEAD | read dummy; then
 		git="${git}-dirty"
+		modified=true
 	fi
 fi
 
@@ -208,7 +229,10 @@ if [ -n "$p4_cmd" ] ; then
 		p4opened=`cd ${SYSDIR} && $p4_cmd opened ./... 2>&1`
 		case "$p4opened" in
 		File*) ;;
-		//*)	p4version="${p4version}+edit" ;;
+		//*)
+			p4version="${p4version}+edit"
+			modified=true
+			;;
 		esac
 		;;
 	*)	unset p4version ;;
@@ -227,10 +251,32 @@ if [ -n "$hg_cmd" ] ; then
 	fi
 fi
 
+include_metadata=true
+while getopts rR opt; do
+	case "$opt" in
+	r)
+		include_metadata=
+		;;
+	R)
+		if [ -z "${modified}" ]; then
+			include_metadata=
+		fi
+	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;