From 96522b887c2da10d21c4b148f13efe4ff0371ada Mon Sep 17 00:00:00 2001
From: Steve Price <steve@FreeBSD.org>
Date: Mon, 28 Apr 1997 03:28:43 +0000
Subject: [PATCH] Sync with NetBSD's revision 1.29 of this file.

Obtained from: NetBSD
---
 bin/sh/expand.c | 82 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 55 insertions(+), 27 deletions(-)

diff --git a/bin/sh/expand.c b/bin/sh/expand.c
index ace411e9c0b5..5d28bec66d82 100644
--- a/bin/sh/expand.c
+++ b/bin/sh/expand.c
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id$
+ *	$Id: expand.c,v 1.16 1997/02/22 13:58:26 peter Exp $
  */
 
 #ifndef lint
@@ -97,7 +97,7 @@ STATIC char *exptilde __P((char *, int));
 STATIC void expbackq __P((union node *, int, int));
 STATIC int subevalvar __P((char *, char *, int, int, int, int));
 STATIC char *evalvar __P((char *, int));
-STATIC int varisset __P((char *));
+STATIC int varisset __P((char *, int));
 STATIC void varvalue __P((char *, int, int));
 STATIC void recordregion __P((int, int, int));
 STATIC void ifsbreakup __P((char *, struct arglist *));
@@ -210,10 +210,10 @@ expandarg(arg, arglist, flag)
 
 STATIC void
 argstr(p, flag)
-	register char *p;
+	char *p;
 	int flag;
 {
-	register char c;
+	char c;
 	int quotes = flag & (EXP_FULL | EXP_CASE);	/* do CTLESC */
 	int firsteq = 1;
 
@@ -325,6 +325,16 @@ expari(flag)
 	int result;
 	int quotes = flag & (EXP_FULL | EXP_CASE);
 
+	while (ifsfirst.next != NULL) {
+		struct ifsregion *ifsp;
+		INTOFF;
+		ifsp = ifsfirst.next->next;
+		ckfree(ifsfirst.next);
+		ifsfirst.next = ifsp;
+		INTON;
+	}
+	ifslastp = NULL;
+
 	/*
 	 * This routine is slightly over-compilcated for
 	 * efficiency.  First we make sure there is
@@ -487,7 +497,7 @@ subevalvar(p, str, strloc, subtype, startloc, varflags)
 		return 0;
 
 	case VSTRIMLEFT:
-		for (loc = startp; loc < str - 1; loc++) {
+		for (loc = startp; loc < str; loc++) {
 			c = *loc;
 			*loc = '\0';
 			if (patmatch(str, startp)) {
@@ -576,7 +586,7 @@ evalvar(p, flag)
 	p = strchr(p, '=') + 1;
 again: /* jump here after setting a variable with ${var=text} */
 	if (special) {
-		set = varisset(var);
+		set = varisset(var, varflags & VSNUL);
 		val = NULL;
 	} else {
 		val = lookupvar(var);
@@ -591,12 +601,10 @@ again: /* jump here after setting a variable with ${var=text} */
 	if (set && subtype != VSPLUS) {
 		/* insert the value of the variable */
 		if (special) {
-			char *exp, *oexpdest = expdest;
 			varvalue(var, varflags & VSQUOTE, flag & EXP_FULL);
 			if (subtype == VSLENGTH) {
-				for (exp = oexpdest;exp != expdest; exp++)
-					varlen++;
-				expdest = oexpdest;
+				varlen = expdest - stackblock() - startloc;
+				STADJUST(-varlen, expdest);
 			}
 		} else {
 			char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
@@ -662,6 +670,10 @@ record:
 		if (subevalvar(p, NULL, expdest - stackblock(), subtype,
 			       startloc, varflags))
 			goto record;
+		else {
+			int amount = (expdest - pat) + 1;
+			STADJUST(-amount, expdest);
+		}
 		break;
 
 	case VSASSIGN:
@@ -708,23 +720,39 @@ record:
  */
 
 STATIC int
-varisset(name)
+varisset(name, nulok)
 	char *name;
-	{
-	char **ap;
+	int nulok;
+{
 
-	if (*name == '!') {
-		if (backgndpid == -1)
-			return 0;
-	} else if (*name == '@' || *name == '*') {
+	if (*name == '!')
+		return backgndpid != -1;
+	else if (*name == '@' || *name == '*') {
 		if (*shellparam.p == NULL)
 			return 0;
+
+		if (nulok) {
+			char **av;
+
+			for (av = shellparam.p; *av; av++)
+				if (**av != '\0')
+					return 1;
+			return 0;
+		}
 	} else if (is_digit(*name)) {
+		char *ap;
 		int num = atoi(name);
-		ap = shellparam.p;
-		while (--num >= 0)
-			if (*ap++ == NULL)
-				return 0;
+
+		if (num > shellparam.nparam)
+			return 0;
+
+		if (num == 0)
+			ap = arg0;
+		else
+			ap = shellparam.p[num - 1];
+
+		if (nulok && (ap == NULL || *ap == '\0'))
+			return 0;
 	}
 	return 1;
 }
@@ -829,7 +857,7 @@ recordregion(start, end, nulonly)
 	int end;
 	int nulonly;
 {
-	register struct ifsregion *ifsp;
+	struct ifsregion *ifsp;
 
 	if (ifslastp == NULL) {
 		ifsp = &ifsfirst;
@@ -859,7 +887,7 @@ ifsbreakup(string, arglist)
 	struct ifsregion *ifsp;
 	struct strlist *sp;
 	char *start;
-	register char *p;
+	char *p;
 	char *q;
 	char *ifs;
 	int ifsspc;
@@ -986,7 +1014,7 @@ expmeta(enddir, name)
 	char *enddir;
 	char *name;
 	{
-	register char *p;
+	char *p;
 	char *q;
 	char *start;
 	char *endname;
@@ -1202,8 +1230,8 @@ pmatch(pattern, string)
 	char *pattern;
 	char *string;
 	{
-	register char *p, *q;
-	register char c;
+	char *p, *q;
+	char c;
 
 	p = pattern;
 	q = string;
@@ -1302,7 +1330,7 @@ void
 rmescapes(str)
 	char *str;
 	{
-	register char *p, *q;
+	char *p, *q;
 
 	p = str;
 	while (*p != CTLESC) {