--- ray/src/rt/persist.c	1993/02/10 11:02:20	2.7
+++ ray/src/rt/persist.c	1996/01/23 15:51:38	2.12
@@ -1,4 +1,4 @@
-/* Copyright (c) 1993 Regents of the University of California */
+/* Copyright (c) 1995 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -25,6 +25,8 @@ extern char	*strcpy(), *index();
 
 extern int	headismine;	/* boolean true if header belongs to me */
 
+extern char	*progname;	/* global program name */
+
 static char	*persistfname = NULL;	/* persist file name */
 static int	persistfd = -1;		/* persist file descriptor */
 
@@ -95,22 +97,22 @@ int sig_noop() {}
 
 pfhold()		/* holding pattern for idle rendering process */
 {
-	char	buf[128];
+	char	buf[512];
 	register int	n;
 				/* close input and output descriptors */
 	close(fileno(stdin));
 	close(fileno(stdout));
 				/* create named pipes for input and output */
-	if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600) < 0)
+	if (mknod(mktemp(strcpy(inpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
 		goto createrr;
-	if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600) < 0)
+	if (mknod(mktemp(strcpy(outpname,TEMPLATE)), S_IFIFO|0600, 0) < 0)
 		goto createrr;
-	sprintf(buf, "%d\n%s\n%s\n", getpid(), inpname, outpname);
-	if (lseek(persistfd, 0L, 0) < 0)
-		error(SYSTEM, "seek error on persist file in pfhold");
+	sprintf(buf, "%s %d\n%s\n%s\n", progname, getpid(), inpname, outpname);
+	if (lseek(persistfd, 0L, 0) < 0 || ftruncate(persistfd, 0L) < 0)
+		error(SYSTEM, "seek/truncate error on persist file");
 	n = strlen(buf);
 	if (write(persistfd, buf, n) < n)
-		error(SYSTEM, "error writing persist file in pfhold");
+		error(SYSTEM, "error writing persist file");
 				/* wait TIMELIM for someone to signal us */
 	signal(SIGIO, sig_noop);
 	alarm(TIMELIM);
@@ -140,22 +142,24 @@ io_process()		/* just act as conduits to and from actu
 {
 	register char	*cp;
 	register int	nr, n;
-	char	buf[4096], *pfin, *pfout;
+	char	buf[512], *pfin, *pfout;
 	int	pid;
 				/* load and close persist file */
-	nr = read(persistfd, buf, sizeof(buf));
+	nr = read(persistfd, buf, sizeof(buf)-1);
 	pfdetach();
 	if (nr < 0)
 		error(SYSTEM, "cannot read persist file");
 	buf[nr] = '\0';
-	if ((cp = index(buf, '\n')) == NULL)
+	if ((cp = index(buf, ' ')) == NULL)
 		goto formerr;
 	*cp++ = '\0';
-	if ((pid = atoi(buf)) <= 0)
+	if ((pid = atoi(cp)) <= 0)
 		goto formerr;
-	pfin = cp;
 	if ((cp = index(cp, '\n')) == NULL)
 		goto formerr;
+	pfin = ++cp;
+	if ((cp = index(cp, '\n')) == NULL)
+		goto formerr;
 	*cp++ = '\0';
 	pfout = cp;
 	if ((cp = index(cp, '\n')) == NULL)
@@ -163,6 +167,10 @@ io_process()		/* just act as conduits to and from actu
 	*cp++ = '\0';
 	if (cp-buf != nr)
 		goto formerr;
+	if (strcmp(buf, progname)) {
+		sprintf(errmsg, "persist file for %s, not %s", buf, progname);
+		error(USER, errmsg);
+	}
 				/* wake up rendering process */
 	if (kill(pid, SIGIO) < 0)
 		error(SYSTEM, "cannot signal rendering process in io_process");
@@ -180,28 +188,16 @@ io_process()		/* just act as conduits to and from actu
 			error(SYSTEM, "cannot open output pipe in io_process");
 	}
 				/* pass input to output */
-	cp = buf; n = sizeof(buf);
-				/* do as much as we can each way */
-	while ((nr = read(0, cp, n)) > 0) {
-		nr += cp-buf;
-		if ((n = write(1, buf, nr)) <= 0)
-			goto writerr;
-		cp = buf;
-		while (n < nr)
-			*cp++ = buf[n++];
-		n = sizeof(buf) - (cp-buf);
-	}
+				/* 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 */
-	nr = cp-buf;		/* write remainder */
-	cp = buf;
-	while (nr > 0) {
-		if ((n = write(1, cp, nr)) <= 0)
-			goto writerr;
-		cp += n;
-		nr -= n;
-	}
 	close(1);		/* close output */
 	if (pid)		/* parent waits for child */
 		wait(0);
@@ -211,5 +207,9 @@ formerr:
 writerr:
 	error(SYSTEM, "write error in io_process");
 }
+
+#else
+
+pfclean() {}
 
 #endif