--- ray/src/rt/persist.c	1993/01/25 19:17:36	2.5
+++ ray/src/rt/persist.c	1993/04/01 08:55:37	2.9
@@ -9,6 +9,9 @@ static char SCCSid[] = "$SunId$ LBL";
  */
 
 #include "standard.h"
+
+#ifdef F_SETLKW
+
 #include "paths.h"
 #include <signal.h>
 #include <sys/types.h>
@@ -168,28 +171,37 @@ io_process()		/* just act as conduits to and from actu
 		error(SYSTEM, "fork failed in io_process");
 				/* connect to appropriate pipe */
 	if (pid) {			/* parent passes renderer output */
-		if (freopen(pfout, "r", stdin) == NULL)
+		close(0);
+		if (open(pfout, O_RDONLY) != 0)
 			error(SYSTEM, "cannot open input pipe in io_process");
 	} else {			/* child passes renderer input */
-		if (freopen(pfin, "w", stdout) == NULL)
-			error(SYSTEM, "cannot open input pipe in io_process");
+		close(1);
+		if (open(pfin, O_WRONLY) != 1)
+			error(SYSTEM, "cannot open output pipe in io_process");
 	}
 				/* pass input to output */
-	cp = buf; n = sizeof(buf);
-	while ((nr = read(fileno(stdin), cp, n)) > 0) {
-		nr += cp-buf;
-		if ((n = write(fileno(stdout), buf, nr)) <= 0)
-			error(SYSTEM, "write error in io_process");
-		cp = buf;
-		while (n < nr)
-			*cp++ = buf[n++];
-		n = sizeof(buf) - (cp-buf);
-	}
-	fclose(stdin);
-	fclose(stdout);
+				/* read as much as we can, write all of it */
+	while ((nr = read(0, cp=buf, sizeof(buf))) > 0)
+		do {
+			if ((n = write(1, cp, nr)) <= 0)
+				goto writerr;
+			cp += n;
+		} while ((nr -= n) > 0);
+	if (nr < 0)
+		error(SYSTEM, "read error in io_process");
+	close(0);		/* close input */
+	close(1);		/* close output */
 	if (pid)		/* parent waits for child */
 		wait(0);
 	exit(0);		/* all done, exit (not quit!) */
 formerr:
 	error(USER, "format error in persist file");
+writerr:
+	error(SYSTEM, "write error in io_process");
 }
+
+#else
+
+pfclean() {}
+
+#endif