plug a few display problems with special parameter name expansions

reported by Stéphane Chazelas

eval.c

@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/eval.c,v 1.183 2016/02/26 18:05:10 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/eval.c,v 1.184 2016/02/26 18:48:12 tg Exp $");
 
 /*
  * string expansion
@@ -404,8 +404,8 @@ expand(
 					st->stype = stype;
 					st->base = Xsavepos(ds, dp);
 					st->f = f;
-					if (x.var == &vtemp) {
+					if (x.var == vtemp) {
-						st->var = tempvar();
+						st->var = tempvar(vtemp->name);
 						st->var->flag &= ~INTEGER;
 						/* can't fail here */
 						setstr(st->var,

expr.c

@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/expr.c,v 1.81 2016/01/14 21:17:50 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/expr.c,v 1.82 2016/02/26 18:48:12 tg Exp $");
 
 /* the order of these enums is constrained by the order of opinfo[] */
 enum token {
@@ -227,7 +227,7 @@ v_evaluate(struct tbl *vp, const char *expr, volatile int error_ok,
 	exprtoken(es);
 	if (es->tok == END) {
 		es->tok = LIT;
-		es->val = tempvar();
+		es->val = tempvar("");
 	}
 	v = intvar(es, evalexpr(es, MAX_PREC));
 
@@ -649,7 +649,7 @@ exprtoken(Expr_state *es)
 			cp += len;
 		}
 		if (es->noassign) {
-			es->val = tempvar();
+			es->val = tempvar("");
 			es->val->flag |= EXPRLVALUE;
 		} else {
 			strndupx(tvar, es->tokp, cp - es->tokp, ATEMP);
@@ -684,7 +684,7 @@ exprtoken(Expr_state *es)
 			c = *cp++;
 		strndupx(tvar, es->tokp, --cp - es->tokp, ATEMP);
  process_tvar:
-		es->val = tempvar();
+		es->val = tempvar("");
 		es->val->flag &= ~INTEGER;
 		es->val->type = 0;
 		es->val->val.s = tvar;
@@ -719,17 +719,19 @@ assign_check(Expr_state *es, enum token op, struct tbl *vasn)
 }
 
 struct tbl *
-tempvar(void)
+tempvar(const char *vname)
 {
 	struct tbl *vp;
+	size_t vsize;
 
-	vp = alloc(sizeof(struct tbl), ATEMP);
+	vsize = strlen(vname) + 1;
+	vp = alloc(offsetof(struct tbl, name[0]) + vsize, ATEMP);
+	memcpy(vp->name, vname, vsize);
 	vp->flag = ISSET|INTEGER;
 	vp->type = 0;
 	vp->areap = ATEMP;
 	vp->ua.hval = 0;
 	vp->val.i = 0;
-	vp->name[0] = '\0';
 	return (vp);
 }
 
@@ -744,7 +746,7 @@ intvar(Expr_state *es, struct tbl *vp)
 	    (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER))
 		return (vp);
 
-	vq = tempvar();
+	vq = tempvar("");
 	if (setint_v(vq, vp, es->arith) == NULL) {
 		if (vp->flag & EXPRINEVAL)
 			evalerr(es, ET_RECURSIVE, vp->name);

main.c

@@ -34,7 +34,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.308 2016/02/24 01:44:46 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.309 2016/02/26 18:48:12 tg Exp $");
 
 extern char **environ;
 
@@ -208,6 +208,8 @@ main_init(int argc, const char *argv[], Source **sp, struct block **lp)
 
 	/* initialise permanent Area */
 	ainit(&aperm);
+	/* max. name length: -2147483648 = 11 (+ NUL) */
+	vtemp = alloc(offsetof(struct tbl, name[0]) + 12, APERM);
 
 	/* set up base environment */
 	env.type = E_NONE;

sh.h

@@ -175,9 +175,9 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.762 2016/02/24 02:08:39 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.763 2016/02/26 18:48:13 tg Exp $");
 #endif
-#define MKSH_VERSION "R52 2016/02/23"
+#define MKSH_VERSION "R52 2016/02/26"
 
 /* arithmetic types: C implementation */
 #if !HAVE_CAN_INTTYPES
@@ -1216,7 +1216,7 @@ struct tbl {
 	char name[4];
 };
 
-EXTERN struct tbl vtemp;
+EXTERN struct tbl *vtemp;
 /* set by global() and local() */
 EXTERN bool last_lookup_was_array;
 
@@ -1768,7 +1768,7 @@ size_t utf_ptradj(const char *) MKSH_A_PURE;
 int utf_wcwidth(unsigned int) MKSH_A_PURE;
 #endif
 int ksh_access(const char *, int);
-struct tbl *tempvar(void);
+struct tbl *tempvar(const char *);
 /* funcs.c */
 int c_hash(const char **);
 int c_pwd(const char **);

var.c

@@ -28,7 +28,7 @@
 #include <sys/sysctl.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/var.c,v 1.198 2016/01/21 18:24:45 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/var.c,v 1.199 2016/02/26 18:48:14 tg Exp $");
 
 /*-
  * Variables
@@ -242,18 +242,26 @@ global(const char *n)
 	if (!ksh_isalphx(c)) {
 		if (array)
 			errorf(Tbadsubst);
-		vp = &vtemp;
+		vp = vtemp;
 		vp->flag = DEFINED;
 		vp->type = 0;
 		vp->areap = ATEMP;
-		*vp->name = c;
 		if (ksh_isdigit(c)) {
-			if (getn(vn, &c) && (c <= l->argc))
+			if (getn(vn, &c)) {
+				/* main.c:main_init() says 12 */
+				shf_snprintf(vp->name, 12, "%d", c);
+				if (c <= l->argc) {
 					/* setstr can't fail here */
-				setstr(vp, l->argv[c], KSH_RETURN_ERROR);
+					setstr(vp, l->argv[c],
+					    KSH_RETURN_ERROR);
+				}
+			} else
+				vp->name[0] = '\0';
 			vp->flag |= RDONLY;
 			goto out;
 		}
+		vp->name[0] = c;
+		vp->name[1] = '\0';
 		vp->flag |= RDONLY;
 		if (vn[1] != '\0')
 			goto out;
@@ -320,7 +328,7 @@ local(const char *n, bool copy)
 	vn = array_index_calc(n, &array, &val);
 	h = hash(vn);
 	if (!ksh_isalphx(*vn)) {
-		vp = &vtemp;
+		vp = vtemp;
 		vp->flag = DEFINED|RDONLY;
 		vp->type = 0;
 		vp->areap = ATEMP;
@@ -479,13 +487,12 @@ void
 setint(struct tbl *vq, mksh_ari_t n)
 {
 	if (!(vq->flag&INTEGER)) {
-		struct tbl *vp = &vtemp;
+		vtemp->flag = (ISSET|INTEGER);
-		vp->flag = (ISSET|INTEGER);
+		vtemp->type = 0;
-		vp->type = 0;
+		vtemp->areap = ATEMP;
-		vp->areap = ATEMP;
+		vtemp->val.i = n;
-		vp->val.i = n;
 		/* setstr can't fail here */
-		setstr(vq, str_val(vp), KSH_RETURN_ERROR);
+		setstr(vq, str_val(vtemp), KSH_RETURN_ERROR);
 	} else
 		vq->val.i = n;
 	vq->flag |= ISSET;