diff -up ksh-20120801/src/cmd/ksh93/include/io.h.safefd ksh-20120801/src/cmd/ksh93/include/io.h

--- ksh-20120801/src/cmd/ksh93/include/io.h.safefd	2015-03-03 18:21:40.544732158 +0100

+++ ksh-20120801/src/cmd/ksh93/include/io.h	2015-03-03 18:22:16.284447849 +0100

@@ -78,6 +78,7 @@ extern void 	sh_iorestore(Shell_t*,int,i

 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 int 	sh_inuse(Shell_t*, int);

 extern void 	sh_iounsave(Shell_t*);

diff -up ksh-20120801/src/cmd/ksh93/sh/io.c.safefd ksh-20120801/src/cmd/ksh93/sh/io.c

--- ksh-20120801/src/cmd/ksh93/sh/io.c.safefd	2015-03-03 18:21:40.511732421 +0100

+++ ksh-20120801/src/cmd/ksh93/sh/io.c	2015-03-03 18:21:40.544732158 +0100

@@ -1724,6 +1724,25 @@ void sh_iosave(Shell_t *shp, register in

 	}

 }

+int safefdnumber(Shell_t* shp, int sfd)

+{

+	register int fd;

+

+	while(1)

+	{

+		for(fd=0; fd < shp->topfd; fd++)

+		{

+			if (filemap[fd].save_fd==sfd || filemap[fd].orig_fd==sfd || (fcntl(sfd, F_GETFD) != -1 || errno != EBADF))

+			{

+				sfd++;

+				continue;

+			}

+		}

+		break;

+	}

+	return sfd;

+}

+

 /*

  *  close all saved file descriptors

  */

diff -up ksh-20120801/src/cmd/ksh93/sh/subshell.c.safefd ksh-20120801/src/cmd/ksh93/sh/subshell.c

--- ksh-20120801/src/cmd/ksh93/sh/subshell.c.safefd	2015-03-03 18:21:40.531732261 +0100

+++ ksh-20120801/src/cmd/ksh93/sh/subshell.c	2015-03-03 18:21:40.544732158 +0100

@@ -673,7 +673,7 @@ Sfio_t *sh_subshell(Shell_t *shp,Shnode_

 			}

 			if(iop && sffileno(iop)==1)

 			{

-				int fd=sfsetfd(iop,3);

+				int fd=sfsetfd(iop,safefdnumber(shp,3));

 				if(fd<0)

 				{

 					shp->toomany = 1;