diff --git a/src/cmd/ksh93/include/io.h b/src/cmd/ksh93/include/io.h

--- a/src/cmd/ksh93/include/io.h

+++ b/src/cmd/ksh93/include/io.h

@@ -79,7 +79,7 @@ extern Sfio_t 	*sh_iostream(Shell_t*,int);

 extern int	sh_redirect(Shell_t*,struct ionod*,int);

 extern void 	sh_iosave(Shell_t *, int,int,char*);

 extern int 	safefdnumber(Shell_t* shp, int sfd);

-extern int 	sh_iovalidfd(Shell_t*, int);

+extern bool 	sh_iovalidfd(Shell_t*, int);

 extern int 	sh_inuse(Shell_t*, int);

 extern void 	sh_iounsave(Shell_t*);

 extern void	iounpipe(Shell_t*);

diff --git a/src/cmd/ksh93/sh/io.c b/src/cmd/ksh93/sh/io.c

--- a/src/cmd/ksh93/sh/io.c

+++ b/src/cmd/ksh93/sh/io.c

@@ -403,38 +403,50 @@ static short		filemapsize;

 /* ======== input output and file copying ======== */

-int  sh_iovalidfd(Shell_t *shp, int fd)

+bool  sh_iovalidfd(Shell_t *shp, int fd)

 {

 	Sfio_t		**sftable = shp->sftable;

 	int		max,n, **fdptrs = shp->fdptrs;

 	unsigned char	*fdstatus = shp->fdstatus;

 	if(fd<0)

-		return(0);

+		return(false);

 	if(fd < shp->gd->lim.open_max)

-		return(1);

+		return(true);

 	max = strtol(astconf("OPEN_MAX",NiL,NiL),NiL,0);

 	if(fd >= max)

 	{

 		errno = EBADF;

-		return(0);

+		return(false);

 	}

 	n = (fd+16)&~0xf;

-	if(n > max)

-		n = max;

+	if(n++ > max)

+		n = max+1;

 	max = shp->gd->lim.open_max;

-	shp->sftable = (Sfio_t**)calloc((n+1)*(sizeof(int*)+sizeof(Sfio_t*)+1),1);

-	if(max)

-		memcpy(shp->sftable,sftable,max*sizeof(Sfio_t*));

+	shp->sftable = (Sfio_t**)calloc((n+1)*(sizeof(int*)+sizeof(Sfio_t*)+sizeof(*fdstatus)),1);

+

+	if(sftable)

+	{

+		--sftable;

+		if(max)

+			memcpy(shp->sftable,sftable,++max*sizeof(Sfio_t*));

+

+	}

+

 	shp->fdptrs = (int**)(&shp->sftable[n]);

 	if(max)

-		memcpy(shp->fdptrs,fdptrs,max*sizeof(int*));

+		memcpy(shp->fdptrs,--fdptrs,max*sizeof(int*));

 	shp->fdstatus = (unsigned char*)(&shp->fdptrs[n]);

 	if(max)

-		memcpy(shp->fdstatus,fdstatus,max);

+		memcpy(shp->fdstatus,--fdstatus,max);

+

 	if(sftable)

 		free((void*)sftable);

-	shp->gd->lim.open_max = n;

-	return(1);

+

+	shp->sftable++;

+	shp->fdptrs++;

+	shp->fdstatus++;

+	shp->gd->lim.open_max = n-1;

+	return(true);

 }

 int  sh_inuse(Shell_t *shp, int fd)