Fix undefined behavior in pty and .sh.match

This pull request fixes a few errors that occur when ksh is built
with -fsanitize=address,undefined.

src/cmd/builtin/pty.c:
- Use long typecasts with PROC_op1, which fixes this error under ASan:
  src/cmd/builtin/pty.c:356:18: runtime error: left shift of 12 by 28 places cannot be represented in type 'int'

src/cmd/ksh93/sh/init.c:
- Ensure mp->nodes is not NULL before making use of it. This change
  fixes two errors under ASan that occur during the exit and glob
  regression tests:
  src/cmd/ksh93/sh/init.c:868:6: runtime error: applying non-zero offset 18446744073709551600 to null pointer
  src/cmd/ksh93/sh/init.c:831:5: runtime error: applying non-zero offset 18446744073709551600 to null pointer

src/lib/libast/include/proc.h:
- Remove the now unused PROC_FD_CTTY macro.

src/cmd/builtin/pty.c

@@ -353,7 +353,7 @@ runcmd(char** argv, int minion, int session)
 
 	if (session)
 	{
-		ops[0] = PROC_FD_CTTY(minion);
+		ops[0] = (long)PROC_op1((long)PROC_fd_ctty,(long)minion);
 		ops[1] = 0;
 	}
 	else

src/cmd/ksh93/sh/init.c

@@ -828,22 +828,25 @@ static void match2d(struct match *mp)
 	int		i;
 	Namarr_t	*ap;
 	nv_disc(SH_MATCHNOD, &mp->hdr, NV_POP);
-	np = nv_namptr(mp->nodes, 0);
-	for(i=0; i < mp->nmatch; i++)
+	if(mp->nodes)
 	{
-		np->nvname = mp->names + 3 * i;
-		if(i > 9)
+		np = nv_namptr(mp->nodes, 0);
+		for(i=0; i < mp->nmatch; i++)
 		{
-			*np->nvname = '0' + i / 10;
-			np->nvname[1] = '0' + (i % 10);
+			np->nvname = mp->names + 3 * i;
+			if(i > 9)
+			{
+				*np->nvname = '0' + i / 10;
+				np->nvname[1] = '0' + (i % 10);
+			}
+			else
+				*np->nvname = '0' + i;
+			nv_putsub(np, NULL, 1);
+			nv_putsub(np, NULL, 0);
+			nv_putsub(SH_MATCHNOD, NULL, i);
+			nv_arraychild(SH_MATCHNOD, np, 0);
+			np = nv_namptr(np + 1, 0);
 		}
-		else
-			*np->nvname = '0' + i;
-		nv_putsub(np, NULL, 1);
-		nv_putsub(np, NULL, 0);
-		nv_putsub(SH_MATCHNOD, NULL, i);
-		nv_arraychild(SH_MATCHNOD, np, 0);
-		np = nv_namptr(np + 1, 0);
 	}
 	if(ap = nv_arrayptr(SH_MATCHNOD))
 		ap->nelem = mp->nmatch;
@@ -865,25 +868,28 @@ void sh_setmatch(const char *v, int vsize, int nmatch, int match[], int index)
 	sh.subshell = 0;
 	if(index<0)
 	{
-		np = nv_namptr(mp->nodes,0);
-		if(mp->index==0)
-			match2d(mp);
-		for(i=0; i < mp->nmatch; i++)
+		if(mp->nodes)
 		{
-			nv_disc(np,&mp->hdr,NV_LAST);
-			nv_putsub(np,NULL,mp->index);
-			for(x=mp->index; x >=0; x--)
-			{
-				n = i + x*mp->nmatch;
-				if(mp->match[2*n+1]>mp->match[2*n])
-					nv_putsub(np,Empty,ARRAY_ADD|x);
-			}
-			if((ap=nv_arrayptr(np)) && array_elem(ap)==0)
+			np = nv_namptr(mp->nodes,0);
+			if(mp->index==0)
+				match2d(mp);
+			for(i=0; i < mp->nmatch; i++)
 			{
-				nv_putsub(SH_MATCHNOD,NULL,i);
-				_nv_unset(SH_MATCHNOD,NV_RDONLY);
+				nv_disc(np,&mp->hdr,NV_LAST);
+				nv_putsub(np,NULL,mp->index);
+				for(x=mp->index; x >=0; x--)
+				{
+					n = i + x*mp->nmatch;
+					if(mp->match[2*n+1]>mp->match[2*n])
+						nv_putsub(np,Empty,ARRAY_ADD|x);
+				}
+				if((ap=nv_arrayptr(np)) && array_elem(ap)==0)
+				{
+					nv_putsub(SH_MATCHNOD,NULL,i);
+					_nv_unset(SH_MATCHNOD,NV_RDONLY);
+				}
+				np = nv_namptr(np+1,0);
 			}
-			np = nv_namptr(np+1,0);
 		}
 		sh.subshell = savesub;
 		return;

src/lib/libast/include/proc.h

@@ -68,7 +68,6 @@
 #define PROC_op2(o,a,b)	(((o)<<(2*PROC_ARG_BIT))|(((b)&PROC_ARG_NULL)<<PROC_ARG_BIT)|((a)&PROC_ARG_NULL))
 
 #define PROC_FD_CLOSE(p,f)	PROC_op2(PROC_fd_dup|(f),p,PROC_ARG_NULL)
-#define PROC_FD_CTTY(f)		PROC_op1(PROC_fd_ctty,f)
 #define PROC_FD_DUP(p,c,f)	PROC_op2(PROC_fd_dup|(f),p,c)
 #define PROC_SIG_DFL(s)		PROC_op1(PROC_sig_dfl,s,0)
 #define PROC_SIG_IGN(s)		PROC_op1(PROC_sig_ign,s,0)