From f52337da206ed2baffc530fe414c3ab974ee400f Mon Sep 17 00:00:00 2001
From: kre <kre@NetBSD.org>
Date: Sun, 14 May 2017 11:23:33 +0000
Subject: [PATCH] Make ${NETBSD_SHELL}  value include (a human recognisable
 form of) MKREPRO_TIMESTAMP (as an additional word in the value, with a
 "BUILD:" prefix) if it is set during the build.   (Trailing 00 pairs in the
 time are removed).

While here, throw in some extra words that list the compilation
options used which alter sh behaviour (mostly by removing stuff.)
Usually that will only be noticed in a SMALL shell compiled for
install media, or similar - none of the others (not that there
are many) are ever changed from the default in a normal build
(default settings are just omitted.)   This also allows scripts
to tell if they are running in a DEBUG shell, which can sometimes
make debugging easier.
---
 bin/sh/Makefile | 10 +++++++++-
 bin/sh/var.c    | 41 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/bin/sh/Makefile b/bin/sh/Makefile
index b6feba2ea895..63f86a8e6b5c 100644
--- a/bin/sh/Makefile
+++ b/bin/sh/Makefile
@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile,v 1.104 2017/03/20 11:26:07 kre Exp $
+#	$NetBSD: Makefile,v 1.105 2017/05/14 11:23:33 kre Exp $
 #	@(#)Makefile	8.4 (Berkeley) 5/5/95
 
 .include <bsd.own.mk>
@@ -29,6 +29,14 @@ CPPFLAGS+=-DSHELL -I. -I${.CURDIR}
 #CFLAGS+=-funsigned-char
 #TARGET_CHARFLAG?= -DTARGET_CHAR="unsigned char" -funsigned-char
 
+# Reproducible build parameters ... export into sh for NETBSD_SHELL setting
+.if ${MKREPRO_TIMESTAMP:Uno} != "no"
+BUILD_DATE!=	date -u -r "${MKREPRO_TIMESTAMP}" "+%Y%m%d%H%M%S"
+# These are (should be) equivalent, but the 2nd is easier to understand
+#CPPFLAGS+= -DBUILD_DATE='"${BUILD_DATE:C/([^0]0?)(00)*$/\1/}Z"'
+CPPFLAGS+= -DBUILD_DATE='"${BUILD_DATE:S/00$//:S/00$//:S/00//}Z"'
+.endif
+
 .ifdef SMALLPROG
 CPPFLAGS+=-DSMALL
 .endif
diff --git a/bin/sh/var.c b/bin/sh/var.c
index abd42bbd5f06..a7e6223c819a 100644
--- a/bin/sh/var.c
+++ b/bin/sh/var.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: var.c,v 1.52 2017/05/10 06:18:43 kre Exp $	*/
+/*	$NetBSD: var.c,v 1.53 2017/05/14 11:23:33 kre Exp $	*/
 
 /*-
  * Copyright (c) 1991, 1993
@@ -37,7 +37,7 @@
 #if 0
 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
 #else
-__RCSID("$NetBSD: var.c,v 1.52 2017/05/10 06:18:43 kre Exp $");
+__RCSID("$NetBSD: var.c,v 1.53 2017/05/14 11:23:33 kre Exp $");
 #endif
 #endif /* not lint */
 
@@ -162,14 +162,45 @@ INIT {
 	}
 
 	/*
+	 * Set variables which override anything read from environment.
+	 *
 	 * PPID is readonly
-	 *	set after processing environ to override anything there
-	 * Always default IFS, ignore any value from environment.
+	 * Always default IFS
+	 * NETBSD_SHELL is a constant (readonly), and is never exported
 	 */
 	snprintf(buf, sizeof(buf), "%d", (int)getppid());
 	setvar("PPID", buf, VREADONLY);
 	setvar("IFS", ifs_default, VTEXTFIXED);
-	setvar("NETBSD_SHELL", NETBSD_SHELL, VTEXTFIXED|VREADONLY|VNOEXPORT);
+
+	setvar("NETBSD_SHELL", NETBSD_SHELL
+#ifdef BUILD_DATE
+		" BUILD:" BUILD_DATE
+#endif
+#ifdef DEBUG
+		" DEBUG"
+#endif
+#if !defined(JOBS) || JOBS == 0
+		" -JOBS"
+#endif
+#ifndef DO_SHAREDVFORK
+		" -VFORK"
+#endif
+#ifdef SMALL
+		" SMALL"
+#endif
+#ifdef TINY
+		" TINY"
+#endif
+#ifdef OLD_TTY_DRIVER
+		" OLD_TTY"
+#endif
+#ifdef SYSV
+		" SYSV"
+#endif
+#ifndef BSD
+		" -BSD"
+#endif
+		    , VTEXTFIXED|VREADONLY|VNOEXPORT);
 }
 #endif