--- ray/src/rt/devcomm.c	1990/02/22 11:46:13	1.12
+++ ray/src/rt/devcomm.c	1993/04/05 15:16:47	2.3
@@ -12,25 +12,17 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include "standard.h"
 
-#include <signal.h>
-
 #include "color.h"
 
 #include "driver.h"
 
+#include "vfork.h"
+
 #ifndef DEVPATH
 #define DEVPATH		getenv("PATH")	/* device search path */
 #endif
 
-#ifndef BSD
-#define vfork		fork
-#endif
-
-extern char	*getpath(), *getenv();
-
-int	onsigio();
-
-int	comm_close(), comm_clear(), comm_paintr(), comm_errout(),
+static int	comm_close(), comm_clear(), comm_paintr(),
 		comm_getcur(), comm_comout(), comm_comin(), comm_flush();
 
 struct driver	comm_driver = {
@@ -43,7 +35,35 @@ FILE	*devin, *devout;
 int	devchild;
 
 
+static struct driver *
+final_connect()				/* verify and initialize connection */
+{
+	putw(COM_SENDM, devout);
+	fflush(devout);
+	if (getw(devin) != COM_RECVM)
+		return(NULL);
+						/* get driver parameters */
+	getstate();
+						/* set error vectors */
+	cmdvec = comm_comout;
+	if (wrnvec != NULL)
+		wrnvec = comm_comout;
+	return(&comm_driver);
+}
+
+
 struct driver *
+slave_init(dname, id)			/* run rview in slave mode */
+char	*dname, *id;
+{
+	devchild = -1;				/* we're the slave here */
+	devout = stdout;			/* use standard input */
+	devin = stdin;				/* and standard output */
+	return(final_connect());		/* verify initialization */
+}
+
+
+struct driver *
 comm_init(dname, id)			/* set up and execute driver */
 char	*dname, *id;
 {
@@ -51,7 +71,7 @@ char	*dname, *id;
 	int	p1[2], p2[2];
 	char	pin[16], pout[16];
 						/* find driver program */
-	if ((devname = getpath(dname, DEVPATH, 1)) == NULL) {
+	if ((devname = getpath(dname, DEVPATH, X_OK)) == NULL) {
 		stderr_v(dname);
 		stderr_v(": not found\n");
 		return(NULL);
@@ -76,22 +96,7 @@ char	*dname, *id;
 		goto syserr;
 	if ((devin = fdopen(p2[0], "r")) == NULL)
 		goto syserr;
-						/* verify & get resolution */
-	putw(COM_SENDM, devout);
-	fflush(devout);
-	if (getw(devin) != COM_RECVM)
-		return(NULL);
-	fread((char *)&comm_driver.pixaspect,
-			sizeof(comm_driver.pixaspect), 1, devin);
-	comm_driver.xsiz = getw(devin);
-	comm_driver.ysiz = getw(devin);
-						/* input handling */
-	signal(SIGIO, onsigio);
-						/* set error vectors */
-	cmdvec = comm_comout;
-	if (wrnvec != NULL)
-		wrnvec = comm_comout;
-	return(&comm_driver);
+	return(final_connect());		/* verify initialization */
 syserr:
 	perror(dname);
 	return(NULL);
@@ -106,9 +111,10 @@ comm_close()			/* done with driver */
 	cmdvec = NULL;				/* reset error vectors */
 	if (wrnvec != NULL)
 		wrnvec = stderr_v;
-	signal(SIGIO, SIG_DFL);
 	fclose(devout);
 	fclose(devin);
+	if (devchild < 0)
+		return;
 	while ((pid = wait(0)) != -1 && pid != devchild)
 		;
 }
@@ -144,6 +150,9 @@ comm_flush()				/* flush output to driver */
 {
 	putc(COM_FLUSH, devout);
 	fflush(devout);
+	if (getc(devin) != COM_FLUSH)
+		reply_error("flush");
+	getstate();
 }
 
 
@@ -170,7 +179,8 @@ char	*str;
 {
 	putc(COM_COMOUT, devout);
 	myputs(str, devout);
-	fflush(devout);
+	if (str[strlen(str)-1] == '\n')
+		fflush(devout);
 }
 
 
@@ -190,21 +200,11 @@ char	*prompt;
 	if (getc(devin) != COM_COMIN)
 		reply_error("comin");
 	mygets(buf, devin);
-	if (comm_driver.inpready > 0)
-		comm_driver.inpready--;
+	getstate();
 }
 
 
 static
-comm_errout(str)			/* display an error message */
-char	*str;
-{
-	comm_comout(str);
-	stderr_v(str);			/* send to standard error also */
-}
-
-
-static
 mygets(s, fp)				/* get string from file (with nul) */
 register char	*s;
 register FILE	*fp;
@@ -240,7 +240,11 @@ char	*routine;
 
 
 static
-onsigio()				/* input ready */
+getstate()				/* get driver state variables */
 {
-	comm_driver.inpready++;
+	fread((char *)&comm_driver.pixaspect,
+			sizeof(comm_driver.pixaspect), 1, devin);
+	comm_driver.xsiz = getw(devin);
+	comm_driver.ysiz = getw(devin);
+	comm_driver.inpready = getw(devin);
 }