From 8cc7fdb8340386c9dbc9af796edbd77c28240db6 Mon Sep 17 00:00:00 2001
From: tg <tg@mirbsd.org>
Date: Tue, 7 Apr 2009 19:43:28 +0000
Subject: [PATCH] "evil" workaround to the alignment issues: embed an
 ALLOC_ITEM into struct env (other structures defined have no "foreign type
 with pos- sible alignment constraints" members) and take care of it while
 dea- ling in a struct env instance

---
 check.t |  4 ++--
 main.c  | 24 ++++++++++++++++++------
 sh.h    |  7 ++++---
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/check.t b/check.t
index bc32908..7841176 100644
--- a/check.t
+++ b/check.t
@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.269 2009/04/06 08:33:36 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.270 2009/04/07 19:43:26 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -7,7 +7,7 @@
 # http://www.research.att.com/~gsf/public/ifs.sh
 
 expected-stdout:
-	@(#)MIRBSD KSH R37 2009/04/05
+	@(#)MIRBSD KSH R37 2009/04/07
 description:
 	Check version of shell.
 stdin:
diff --git a/main.c b/main.c
index 7459c8b..3323246 100644
--- a/main.c
+++ b/main.c
@@ -13,7 +13,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.124 2009/04/05 12:35:31 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.125 2009/04/07 19:43:27 tg Exp $");
 
 extern char **environ;
 
@@ -620,15 +620,23 @@ void
 newenv(int type)
 {
 	struct env *ep;
+	char *cp;
 
-	ep = alloc(sizeof (struct env), ATEMP);
-	ep->type = type;
-	ep->flags = 0;
+	/*
+	 * struct env includes ALLOC_ITEM for alignment constraints
+	 * so first get the actually used memory, then assign it
+	 */
+	cp = alloc(sizeof (struct env) - ALLOC_SIZE, ATEMP);
+	ep = (void *)(cp - ALLOC_SIZE);	/* undo what alloc() did */
+	/* initialise public members of struct env (not the ALLOC_ITEM) */
 	ainit(&ep->area);
+	ep->oenv = e;
 	ep->loc = e->loc;
 	ep->savefd = NULL;
-	ep->oenv = e;
 	ep->temps = NULL;
+	ep->type = type;
+	ep->flags = 0;
+	/* jump buffer is invalid because flags == 0 */
 	e = ep;
 }
 
@@ -636,6 +644,7 @@ void
 quitenv(struct shf *shf)
 {
 	struct env *ep = e;
+	char *cp;
 	int fd;
 
 	if (ep->oenv && ep->oenv->loc != ep->loc)
@@ -684,7 +693,10 @@ quitenv(struct shf *shf)
 	reclaim();
 
 	e = e->oenv;
-	afree(ep, ATEMP);
+
+	/* free the struct env - tricky due to the ALLOC_ITEM inside */
+	cp = (void *)ep;
+	afree(cp + ALLOC_SIZE, ATEMP);
 }
 
 /* Called after a fork to cleanup stuff left over from parents environment */
diff --git a/sh.h b/sh.h
index c9db78d..7c8c1c4 100644
--- a/sh.h
+++ b/sh.h
@@ -102,9 +102,9 @@
 #define __SCCSID(x)	__IDSTRING(sccsid,x)
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.292 2009/04/07 18:56:51 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.293 2009/04/07 19:43:28 tg Exp $");
 #endif
-#define MKSH_VERSION "R37 2009/04/05"
+#define MKSH_VERSION "R37 2009/04/07"
 
 #ifndef MKSH_INCLUDES_ONLY
 
@@ -445,10 +445,11 @@ EXTERN Area aperm;		/* permanent object space */
  * parsing & execution environment
  */
 extern struct env {
+	ALLOC_ITEM __alloc_i;	/* internal, do not touch */
 	Area area;		/* temporary allocation area */
+	struct env *oenv;	/* link to previous environment */
 	struct block *loc;	/* local variables and functions */
 	short *savefd;		/* original redirected fds */
-	struct env *oenv;	/* link to previous environment */
 	struct temp *temps;	/* temp files */
 	sigjmp_buf jbuf;	/* long jump back to env creator */
 	short type;		/* environment type - see below */