diff -up ksh-20100621/src/cmd/ksh93/include/io.h.macrob ksh-20100621/src/cmd/ksh93/include/io.h
--- ksh-20100621/src/cmd/ksh93/include/io.h.macrob	2013-05-14 18:23:05.703939025 +0200
+++ ksh-20100621/src/cmd/ksh93/include/io.h	2013-05-14 18:23:05.718939148 +0200
@@ -68,6 +68,7 @@ extern void 	sh_ioinit(Shell_t*);
 extern int 	sh_iomovefd(int);
 extern int	sh_iorenumber(Shell_t*,int,int);
 extern void 	sh_pclose(int[]);
+extern int	sh_rpipe(int[]);
 extern void 	sh_iorestore(Shell_t*,int,int);
 #if defined(__EXPORT__) && defined(_BLD_DLL) && defined(_BLD_shell) 
    __EXPORT__
@@ -78,6 +79,7 @@ extern void 	sh_iosave(Shell_t *, int,in
 extern int 	sh_iovalidfd(Shell_t*, int);
 extern int 	sh_inuse(int);
 extern void 	sh_iounsave(Shell_t*);
+extern void	iounpipe(Shell_t*);
 extern int	sh_chkopen(const char*);
 extern int	sh_ioaccess(int,int);
 extern int	sh_devtofd(const char*);
diff -up ksh-20100621/src/cmd/ksh93/sh/io.c.macrob ksh-20100621/src/cmd/ksh93/sh/io.c
--- ksh-20100621/src/cmd/ksh93/sh/io.c.macrob	2013-05-14 18:23:05.704939033 +0200
+++ ksh-20100621/src/cmd/ksh93/sh/io.c	2013-05-14 18:23:05.719939157 +0200
@@ -858,18 +858,43 @@ int sh_iomovefd(register int fdold)
  */
 int	sh_pipe(register int pv[])
 {
+	Shell_t *shp = sh_getinterp();
 	int fd[2];
 	if(pipe(fd)<0 || (pv[0]=fd[0])<0 || (pv[1]=fd[1])<0)
 		errormsg(SH_DICT,ERROR_system(1),e_pipe);
 	pv[0] = sh_iomovefd(pv[0]);
 	pv[1] = sh_iomovefd(pv[1]);
-	sh.fdstatus[pv[0]] = IONOSEEK|IOREAD;
-	sh.fdstatus[pv[1]] = IONOSEEK|IOWRITE;
+	shp->fdstatus[pv[0]] = IONOSEEK|IOREAD;
+	shp->fdstatus[pv[1]] = IONOSEEK|IOWRITE;
 	sh_subsavefd(pv[0]);
 	sh_subsavefd(pv[1]);
 	return(0);
 }
 
+#ifndef pipe
+   int	sh_rpipe(register int pv[])
+   {
+   	return sh_pipe(pv);
+   }
+#else
+#  undef pipe
+   /* create a real pipe when pipe() is socketpair */
+   int	sh_rpipe(register int pv[])
+   {
+	Shell_t *shp = sh_getinterp();
+	int fd[2];
+	if(pipe(fd)<0 || (pv[0]=fd[0])<0 || (pv[1]=fd[1])<0)
+		errormsg(SH_DICT,ERROR_system(1),e_pipe);
+	pv[0] = sh_iomovefd(pv[0]);
+	pv[1] = sh_iomovefd(pv[1]);
+	shp->fdstatus[pv[0]] = IONOSEEK|IOREAD;
+	shp->fdstatus[pv[1]] = IONOSEEK|IOWRITE;
+	sh_subsavefd(pv[0]);
+	sh_subsavefd(pv[1]);
+	return(0);
+   }
+#endif
+
 static int pat_seek(void *handle, const char *str, size_t sz)
 {
 	char **bp = (char**)handle;
diff -up ksh-20100621/src/cmd/ksh93/sh/subshell.c.macrob ksh-20100621/src/cmd/ksh93/sh/subshell.c
--- ksh-20100621/src/cmd/ksh93/sh/subshell.c.macrob	2013-05-14 18:23:05.715939124 +0200
+++ ksh-20100621/src/cmd/ksh93/sh/subshell.c	2013-05-14 18:23:05.719939157 +0200
@@ -165,7 +165,7 @@ void sh_subfork(void)
 {
 	register struct subshell *sp = subshell_data;
 	Shell_t	*shp = sp->shp;
-	int	curenv = shp->curenv;
+	int	curenv = shp->curenv, comsub=shp->comsub;
 	pid_t pid;
 	char *trap = shp->st.trapcom[0];
 	if(trap)
@@ -174,6 +174,7 @@ void sh_subfork(void)
 	if(sp->pipe)
 		sh_subtmpfile(shp);
 	shp->curenv = 0;
+	shp->savesig = -1;
 	if(pid = sh_fork(FSHOWME,NIL(int*)))
 	{
 		shp->curenv = curenv;
@@ -197,7 +198,8 @@ void sh_subfork(void)
 		shp->comsub = 0;
 		SH_SUBSHELLNOD->nvalue.s = 0;
 		sp->subpid=0;
-		shp->st.trapcom[0] = trap;
+		shp->st.trapcom[0] = (comsub==2?NULL:trap);
+		shp->savesig = 0;
 	}
 }
 
@@ -696,7 +698,6 @@ Sfio_t *sh_subshell(Shnode_t *t, int fla
 		shp->coutpipe = sp->coutpipe;
 	}
 	shp->subshare = sp->subshare;
-	shp->comsub = sp->comsub;
 	shp->subdup = sp->subdup;
 	if(shp->subshell)
 		SH_SUBSHELLNOD->nvalue.s = --shp->subshell;
@@ -717,10 +718,21 @@ Sfio_t *sh_subshell(Shnode_t *t, int fla
 	}
 	sh_sigcheck();
 	shp->trapnote = 0;
+	nsig = shp->savesig;
+	shp->savesig = 0;
+	if(nsig>0)
+		sh_fault(nsig);
 	if(sp->subpid)
+	{
 		job_wait(sp->subpid);
+		if(comsub>1)
+			iounpipe(shp);
+	}
+	shp->comsub = sp->comsub;
 	if(comsub && iop && sp->pipefd<0)
 		 sfseek(iop,(off_t)0,SEEK_SET);
+	if(shp->trapnote)
+		sh_chktrap();
 	if(shp->exitval > SH_EXITSIG)
 	{
 		int sig = shp->exitval&SH_EXITMASK;
diff -up ksh-20100621/src/cmd/ksh93/sh/xec.c.macrob ksh-20100621/src/cmd/ksh93/sh/xec.c
--- ksh-20100621/src/cmd/ksh93/sh/xec.c.macrob	2013-05-14 18:23:05.716939132 +0200
+++ ksh-20100621/src/cmd/ksh93/sh/xec.c	2013-05-14 18:23:28.089123586 +0200
@@ -84,18 +84,32 @@ struct funenv
  * to use a pipe and to wait for the pipe to close before restoring to a
  * temp file.
  */
-static int	subpipe[3] = {-1};
-static int	subdup,tsetio;
-static void iousepipe(Shell_t *shp)
-{
-	int i;
-	fcntl(subpipe[0],F_SETFD,FD_CLOEXEC);
-	subpipe[2] = sh_fcntl(1,F_DUPFD,10);
-	fcntl(subpipe[2],F_SETFD,FD_CLOEXEC);
+static int      subpipe[3],subdup,tsetio,usepipe;
+void iounpipe(Shell_t*);
+
+int iousepipe(Shell_t *shp)
+{
+	int fd=sffileno(sfstdout),i,err=errno;
+	if(usepipe)
+	{
+		usepipe++;
+		iounpipe(shp);
+	}
+	if(sh_rpipe(subpipe) < 0)
+		return(0);
+	usepipe++;
+	if(shp->comsub!=1)
+	{
+		subpipe[2] = sh_fcntl(subpipe[1],F_DUPFD,10);
+		sh_close(subpipe[1]);
+		return(1);
+	}
+	subpipe[2] = sh_fcntl(fd,F_dupfd_cloexec,10);
 	shp->fdstatus[subpipe[2]] = shp->fdstatus[1];
-	close(1);
-	fcntl(subpipe[1],F_DUPFD,1);
-	shp->fdstatus[1] = shp->fdstatus[subpipe[1]];
+	while(close(fd)<0 && errno==EINTR)
+		errno = err;
+	fcntl(subpipe[1],F_DUPFD,fd);
+	shp->fdstatus[1] = shp->fdstatus[subpipe[1]]&~IOCLEX;
 	sh_close(subpipe[1]);
 	if(subdup=shp->subdup) for(i=0; i < 10; i++)
 	{
@@ -106,14 +120,25 @@ static void iousepipe(Shell_t *shp)
 			shp->fdstatus[i] = shp->fdstatus[1];
 		}
 	}
+	return(1);
 }
 
-static void iounpipe(Shell_t *shp)
+void iounpipe(Shell_t *shp)
 {
-	int n;
+	int fd=sffileno(sfstdout),n,err=errno;
 	char buff[SF_BUFSIZE];
-	close(1);
-	fcntl(subpipe[2], F_DUPFD, 1);
+	if(!usepipe)
+		return;
+	--usepipe;
+	if(shp->comsub>1)
+	{
+		sh_close(subpipe[2]);
+		while(read(subpipe[0],buff,sizeof(buff))>0);
+		goto done;
+	}
+	while(close(fd)<0 && errno==EINTR)
+		errno = err;
+	fcntl(subpipe[2], F_DUPFD, fd);
 	shp->fdstatus[1] = shp->fdstatus[subpipe[2]];
 	if(subdup) for(n=0; n < 10; n++)
 	{
@@ -126,16 +151,35 @@ static void iounpipe(Shell_t *shp)
 	}
 	shp->subdup = 0;
 	sh_close(subpipe[2]);
-	while((n = read(subpipe[0],buff,sizeof(buff)))!=0)
+	if(usepipe==0) while(1)
 	{
+		while(job.waitsafe && job.savesig==SIGCHLD)
+		{
+			if(!vmbusy())
+			{
+				job.in_critical++;
+				job_reap(SIGCHLD);
+				job.in_critical--;
+				break;
+			}
+			sh_delay(1);
+		}
+		if((n = read(subpipe[0],buff,sizeof(buff)))==0)
+			break;
 		if(n>0)
 			sfwrite(sfstdout,buff,n);
 		else if(errno!=EINTR)
 			break;
 	}
+done:
 	sh_close(subpipe[0]);
 	subpipe[0] = -1;
 	tsetio = 0;
+	if(usepipe)
+	{
+		usepipe = 0;
+		iousepipe(shp);
+	}
 }
 
 /*
@@ -723,6 +767,7 @@ int sh_exec(register const Shnode_t *t,
 {
 	register Shell_t	*shp = &sh;
 	Stk_t			*stkp = shp->stk;
+	int			unpipe=0;
 	sh_sigcheck();
 	if(t && !shp->st.execbrk && !sh_isoption(SH_NOEXEC))
 	{
@@ -1256,18 +1301,20 @@ int sh_exec(register const Shnode_t *t,
 			if(shp->subshell)
 			{
 				sh_subtmpfile(shp);
-				subpipe[0] = -1;
-				if(shp->comsub==1 && !(shp->fdstatus[1]&IONOSEEK) && sh_pipe(subpipe)>=0)
-					iousepipe(shp);
 				if((type&(FAMP|TFORK))==(FAMP|TFORK))
-					sh_subfork();
+				{
+					if(shp->comsub && !(shp->fdstatus[1]&IONOSEEK))
+					{
+						unpipe = iousepipe(shp);
+						sh_subfork();
+					}
+				}
 			}
-			no_fork = !ntflag && !(type&(FAMP|FPOU)) &&
+			no_fork = !ntflag && !(type&(FAMP|FPOU)) && !shp->subshell &&
 			    !(shp->st.trapcom[SIGINT] && *shp->st.trapcom[SIGINT]) &&
 			    !shp->st.trapcom[0] && !shp->st.trap[SH_ERRTRAP] &&
 				((struct checkpt*)shp->jmplist)->mode!=SH_JMPEVAL &&
-				(execflg2 || (execflg && 
-				!shp->subshell && shp->fn_depth==0 &&
+				(execflg2 || (execflg && shp->fn_depth==0 &&
 				!(pipejob && sh_isoption(SH_PIPEFAIL))
 			    ));
 			if(sh_isstate(SH_PROFILE) || shp->dot_depth)
@@ -1306,7 +1353,7 @@ int sh_exec(register const Shnode_t *t,
 					parent = sh_fork(type,&jobid);
 				if(parent<0)
 				{
-					if(shp->comsub==1 && subpipe[0]>=0)
+					if(shp->comsub==1 && usepipe && unpipe)
 						iounpipe(shp);
 					break;
 				}
@@ -1323,7 +1370,7 @@ int sh_exec(register const Shnode_t *t,
 #   endif /* _lib_fork */
 				if(parent<0)
 				{
-					if(shp->comsub==1 && subpipe[0]>=0)
+					if(shp->comsub==1 && usepipe && unpipe)
 						iounpipe(shp);
 					break;
 				}
@@ -1360,7 +1407,7 @@ int sh_exec(register const Shnode_t *t,
 						shp->pipepid = parent;
 					else
 						job_wait(parent);
-					if(tsetio &&  subdup)
+					if(usepipe && tsetio &&  subdup)
 						iounpipe(shp);
 					if(!sh_isoption(SH_MONITOR))
 					{
@@ -1534,6 +1581,8 @@ int sh_exec(register const Shnode_t *t,
 					if(type || !sh_isoption(SH_PIPEFAIL))
 						shp->exitval = type;
 				}
+				if(shp->comsub==1 && usepipe)
+					iounpipe(shp);
 				shp->pipepid = 0;
 				shp->st.ioset = 0;
 				if(simple && was_errexit)
@@ -1598,7 +1647,11 @@ int sh_exec(register const Shnode_t *t,
 			pid_t	savepgid = job.curpgid;
 			job.curpgid = 0;
 			if(shp->subshell)
+			{
 				sh_subtmpfile(shp);
+				if(shp->comsub==1 && !(shp->fdstatus[1]&IONOSEEK))
+					iousepipe(shp);
+			}
 			shp->inpipe = pvo;
 			shp->outpipe = pvn;
 			pvo[1] = -1;
@@ -1609,15 +1662,11 @@ int sh_exec(register const Shnode_t *t,
 			job_lock();
 			do
 			{
-#if SHOPT_FASTPIPE
-				type = pipe_exec(shp,pvn,t->lst.lstlef, errorflg);
-#else
 				/* create the pipe */
 				sh_pipe(pvn);
 				/* execute out part of pipe no wait */
 				(t->lst.lstlef)->tre.tretyp |= showme;
 				type = sh_exec(t->lst.lstlef, errorflg);
-#endif /* SHOPT_FASTPIPE */
 				pipejob=1;
 				/* save the pipe stream-ids */
 				pvo[0] = pvn[0];
@@ -2617,6 +2666,7 @@ pid_t _sh_fork(register pid_t parent,int
 	if(sig>0)
 		sh_fault(sig);
 	sh_sigcheck();
+	usepipe=0;
 	return(0);
 }
 
@@ -2643,10 +2693,13 @@ pid_t sh_fork(int flags, int *jobid)
 	sh.savesig = -1;
 	while(_sh_fork(parent=fork(),flags,jobid) < 0);
 	sh_stats(STAT_FORKS);
-	sig = sh.savesig;
-	sh.savesig = 0;
-	if(sig>0)
-		sh_fault(sig);
+	if(!sh.subshell)
+	{
+		sig = sh.savesig;
+		sh.savesig = 0;
+		if(sig>0)
+			sh_fault(sig);
+	}
 	job_fork(parent);
 	return(parent);
 }
diff -up ksh-20100621/src/lib/libast/features/fcntl.c.macrob ksh-20100621/src/lib/libast/features/fcntl.c
--- ksh-20100621/src/lib/libast/features/fcntl.c.macrob	2006-10-26 19:19:10.000000000 +0200
+++ ksh-20100621/src/lib/libast/features/fcntl.c	2013-05-14 18:23:05.721939173 +0200
@@ -219,6 +219,11 @@ main()
 	}
 	printf("\n");
 #endif
+#ifdef F_DUPFD_CLOEXEC
+	printf("#define F_dupfd_cloexec	F_DUPFD_CLOEXEC\n");
+#else
+	printf("#define F_dupfd_cloexec	F_DUPFD\n");
+#endif
 
 #ifndef	O_APPEND
 #define NEED_O	1
@@ -315,6 +320,11 @@ main()
 #ifndef	O_BINARY
 	printf("#define O_BINARY		0\n");
 #endif
+#ifdef	O_CLOEXEC
+	printf("#define O_cloexec		O_CLOEXEC\n");
+#else
+	printf("#define O_cloexec		0\n");
+#endif
 #ifndef	O_TEMPORARY
 	printf("#define O_TEMPORARY		0\n");
 #endif