Remove broken iousepipe/sh_iounpipe (re: a2196f94)

After that commit, iousepipe(), sh_iounpipe(), and supporting flags
were all broken and dead code. Since all command substitutions use
temp files now, they're unused; remove them.

I'm experimenting with reintroducing pipes to command substitutions
in a consistent way, as this is needed for them to wait for
grandchildren. If and when I ever manage to figure out how to do
that in a way that doesn't cause severe hanging and crashing bugs,
these functions may return in some form.

Related: https://github.com/ksh93/ksh/issues/124

src/cmd/ksh93/include/shell.h

@@ -329,7 +329,6 @@ struct Shell_s
 	char		redir0;		/* redirect of 0 */
 	char		intrace;	/* set when trace expands PS4 */
 	char		*readscript;	/* set before reading a script */
-	int		subdup;		/* bitmask for dups of 1 */
 	int		*inpipe;	/* input pipe pointer */
 	int		*outpipe;	/* output pipe pointer */
 	int		cpipe[3];

src/cmd/ksh93/sh/args.c

@@ -721,7 +721,7 @@ struct argnod *sh_argprocsub(struct argnod *argp)
 	ap->argflag |= ARG_MAKE;
 	ap->argflag &= ~ARG_RAW;
 	fd = argp->argflag&ARG_RAW;
-	if(fd==0 && sh.subshell)
+	if(fd==0 && sh.comsub)
 		sh_subtmpfile();
 #if SHOPT_DEVFD
 	sfwrite(sh.stk,e_devfdNN,8);

src/cmd/ksh93/sh/io.c

@@ -1173,7 +1173,7 @@ int	sh_redirect(struct ionod *iop, int flag)
 			memset(ap, 0, ARGVAL);
 			if(iof&IOPUT)
 				ap->argflag = ARG_RAW;
-			else if(sh.subshell)
+			else if(sh.comsub)
 				sh_subtmpfile();
 			ap->argchn.ap = (struct argnod*)fname;
 			ap = sh_argprocsub(ap);
@@ -1241,16 +1241,12 @@ int	sh_redirect(struct ionod *iop, int flag)
 					}
 					if(sh.subshell && dupfd==1)
 					{
-						if(sfset(sfstdout,0,0)&SF_STRING)
+						if(sh.comsub)
 							sh_subtmpfile();
-						if(sh.comsub==1)
-							sh.subdup |= 1<<fn;
 						dupfd = sffileno(sfstdout);
 					}
 					else if(sh.sftable[dupfd])
 						sfsync(sh.sftable[dupfd]);
-					if(dupfd!=1 && fn < 10)
-						sh.subdup &= ~(1<<fn);
 				}
 				else if(fd=='-' && fname[1]==0)
 				{

src/cmd/ksh93/sh/subshell.c

@@ -89,7 +89,6 @@ static struct subshell
 	pid_t		cpid;
 	int		coutpipe;
 	int		cpipe;
-	int		subdup;
 	char		subshare;
 	char		comsub;
 	unsigned int	rand_seed;  /* parent shell $RANDOM seed */
@@ -500,8 +499,6 @@ Sfio_t *sh_subshell(Shnode_t *t, volatile int flags, int comsub)
 	subshell_data = sp;
 	sp->options = sh.options;
 	sp->jobs = job_subsave();
-	sp->subdup = sh.subdup;
-	sh.subdup = 0;
 	/* make sure initialization has occurred */ 
 	if(!sh.pathlist)
 	{
@@ -872,7 +869,6 @@ Sfio_t *sh_subshell(Shnode_t *t, volatile int flags, int comsub)
 			sh.exitval |= SH_EXITSIG;
 	}
 	sh.subshare = sp->subshare;
-	sh.subdup = sp->subdup;
 	sh.subshell--;			/* decrease level of virtual subshells */
 	sh.realsubshell--;		/* decrease ${.sh.subshell} */
 	subshell_data = sp->prev;
@@ -898,11 +894,7 @@ Sfio_t *sh_subshell(Shnode_t *t, volatile int flags, int comsub)
 	if(nsig>0)
 		kill(sh.current_pid,nsig);
 	if(sp->subpid)
-	{
 		job_wait(sp->subpid);
-		if(comsub)
-			sh_iounpipe();
-	}
 	sh.comsub = sp->comsub;
 	if(comsub && iop && sp->pipefd<0)
 		sfseek(iop,(off_t)0,SEEK_SET);

src/cmd/ksh93/sh/xec.c

@@ -166,43 +166,6 @@ static inline double timeval_to_double(struct timeval tv)
 }
 #endif
 
-/*
- * The following two functions allow command substitution for non-builtins
- * to use a pipe and to wait for the pipe to close before restoring to a
- * temp file.
- */
-static int      subpipe[3],subdup,tsetio,usepipe;
-
-static int iousepipe(void)
-{
-	if(usepipe)
-	{
-		usepipe++;
-		sh_iounpipe();
-	}
-	if(sh_rpipe(subpipe) < 0)
-		return(0);
-	usepipe++;
-	subpipe[2] = sh_fcntl(subpipe[1],F_DUPFD,10);
-	sh_close(subpipe[1]);
-	return(1);
-}
-
-void sh_iounpipe(void)
-{
-	char buff[SF_BUFSIZE];
-	if(!usepipe)
-		return;
-	--usepipe;
-	sh_close(subpipe[2]);
-	while(read(subpipe[0],buff,sizeof(buff))>0)
-		;
-	sh_close(subpipe[0]);
-	subpipe[0] = -1;
-	tsetio = 0;
-	usepipe = 0;
-}
-
 /*
  * print time <t> in h:m:s format with precision <p>
  */
@@ -1282,7 +1245,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 						bp->sigset = 0;
 						bp->notify = 0;
 						bp->flags = (OPTIMIZE!=0);
-						if(sh.subshell && nv_isattr(np,BLT_NOSFIO))
+						if(sh.comsub && nv_isattr(np,BLT_NOSFIO))
 							sh_subtmpfile();
 						if(argn)
 							sh.exitval = (*sh.bltinfun)(argn,com,(void*)bp);
@@ -1482,7 +1445,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			register pid_t parent;
 			int no_fork,jobid;
 			int pipes[3];
-			if(sh.subshell)
+			if(sh.comsub)
 				sh_subtmpfile();
 			if(no_fork = check_exec_optimization(type,execflg,execflg2,t->fork.forkio))
 				job.parent=parent=0;
@@ -1860,7 +1823,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			echeck = 1;
 			job.exitval = 0;
 			job.curjobid = 0;
-			if(sh.subshell)
+			if(sh.comsub)
 				sh_subtmpfile();
 			sh.inpipe = pvo;
 			sh.outpipe = pvn;
@@ -2938,7 +2901,6 @@ pid_t _sh_fork(register pid_t parent,int flags,int *jobid)
 	if(sig>0)
 		kill(sh.current_pid,sig);
 	sh_sigcheck();
-	usepipe=0;
 	return(0);
 }
 

src/cmd/ksh93/tests/basic.sh

@@ -413,13 +413,13 @@ unset foo
 unset foo
 foo=$(false) > /dev/null && err_exit 'failed command substitution with redirection not returning false'
 expected=foreback
-got=`print -n fore; (sleep 2;print back)&`
+got=`print -n fore; (sleep .01; print back)&`
 [[ $got == $expected ]] || err_exit "\`\` command substitution background process output error (expected '$expected', got '$got')"
-got=$(print -n fore; (sleep .2;print back)&)
+got=$(print -n fore; (sleep .01; print back)&)
 [[ $got == $expected ]] || err_exit "\$() command substitution background process output error (expected '$expected', got '$got')"
-got=${ print -n fore; (sleep 2;print back)& }
+got=${ print -n fore; (sleep .01; print back)& }
 [[ $got == $expected ]] || err_exit "\${} shared-state command substitution background process output error (expected '$expected', got '$got')"
-function abc { sleep 2; print back; }
+function abc { sleep .01; print back; }
 function abcd { abc & }
 got=$(print -n fore;abcd)
 [[ $got == $expected ]] || err_exit "\$() command substitution background with function process output error (expected '$expected', got '$got')"

src/cmd/ksh93/tests/heredoc.sh

@@ -121,11 +121,15 @@ $0
 $SHELL -c 'x=$(
 cat << EOF
 EOF)' 2> /dev/null || err_exit 'here-doc cannot be terminated by )'
-if	[[ $( IFS=:;cat <<-!
+
+got=$(	IFS=:; cat <<-!
 			$IFS$(print hi)$IFS
-		!) != :hi: ]]
+	!
-then	err_exit '$IFS unset by command substitution in here docs'
+)
-fi
+exp=:hi:
+[[ $got == "$exp" ]] || err_exit '$IFS unset by command substitution in here docs' \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+
 if	x=$($SHELL -c 'cat <<< "hello world"' 2> /dev/null)
 then	[[ $x == 'hello world' ]] || err_exit '<<< documents not working'
 	x=$($SHELL -c 'v="hello  world";cat <<< $v' 2> /dev/null)