Eliminate large stack-allocated buffers, and set the stack size to 1.5k.

Also includes code to check the stack usage, which in my testing showed a maximum of 1025 bytes.

telnetd/ext.h

@@ -80,6 +80,9 @@ extern int	pty, net;
 extern char	line[32];
 extern int	SYNCHing;		/* we are in TELNET SYNCH mode */
 
+/* Buffer for miscellaneous uses in various functions */
+extern char     buf[BUFSIZ > 1024 ? BUFSIZ : 1024];
+
 extern void
 	_termstat(void),
 	add_slc(char, char, cc_t),

telnetd/state.c

@@ -1495,7 +1495,7 @@ doclientstat(void)
 void
 send_status(void)
 {
-	unsigned char statusbuf[256];
+	static unsigned char statusbuf[256];
 	unsigned char *ncp;
 	unsigned char i;
 

telnetd/sys_term.c

@@ -1288,5 +1288,5 @@ cleanup(int sig __unused)
 {
 
 	(void) shutdown(net, SHUT_RDWR);
-	_exit(1);
+	exit(1);
 }

telnetd/telnetd.c

@@ -43,6 +43,7 @@ static const char sccsid[] = "@(#)telnetd.c	8.4 (Berkeley) 5/30/95";
 #include "pathnames.h"
 
 #ifdef __GNO__
+#include <gno/gno.h>
 #include "libtelnet/getaddrinfo.h"
 /* GNO doesn't have struct sockaddr_storage; just use "struct sockaddr" 
  * (which is really struct osockaddr). */
@@ -65,6 +66,10 @@ int	auth_level = 0;
 #endif
 #include "libtelnet/misc.h"
 
+#ifdef __ORCAC__
+#pragma stacksize 1536
+#endif
+
 char	remote_hostname[MAXHOSTNAMELEN];
 size_t	utmp_len = sizeof(remote_hostname) - 1;
 int	registerd_host_only = 0;
@@ -145,16 +150,26 @@ main(int argc, char *argv[])
 #endif
 	char *ep;
 
+
+#ifdef __GNO__
+	if (getenv("TELNETD_STACKCHECK") != NULL)
+		_reportStack();
+
+	/* Make sure our environment is isolated from the parent process's */
+	if (environPush() == 0)
+		atexit(environPop);
+	else
+		exit(1);
+	environInit();
+#endif
+
 	pfrontp = pbackp = ptyobuf;
 	netip = netibuf;
 	nfrontp = nbackp = netobuf;
 #ifdef	ENCRYPTION
 	nclearto = 0;
 #endif	/* ENCRYPTION */
-    
+
-#ifdef __GNO__
-    environInit();
-#endif
 
 	/*
 	 * This initialization causes linemode to default to a configuration
@@ -579,7 +594,7 @@ getterminaltype(char *name undef2)
 	    ttloop();
     }
     if (his_state_is_will(TELOPT_TTYPE)) {
-	char first[256], last[256];
+	static char first[256], last[256];
 
 	while (sequenceIs(ttypesubopt, baseline))
 	    ttloop();
@@ -647,8 +662,6 @@ _gettermname(void)
 int
 terminaltypeok(char *s)
 {
-    char buf[1024];
-
     if (terminaltype == NULL)
 	return(1);
 
@@ -768,8 +781,8 @@ telnet(int f, int p, char *host)
 {
 	int on = 1;
 #define	TABBUFSIZ	512
-	char	defent[TABBUFSIZ];
+	char	*defent = buf;
-	char	defstrs[TABBUFSIZ];
+	char	*defstrs = buf + TABBUFSIZ;
 #undef	TABBUFSIZ
 	char *HE;
 	char *HN;

telnetd/utility.c

@@ -326,8 +326,6 @@ netflush(void)
 void
 fatal(int f, const char *msg)
 {
-	char buf[BUFSIZ];
-
 	(void) snprintf(buf, sizeof(buf), "telnetd: %s.\r\n", msg);
 #ifdef	ENCRYPTION
 	if (encrypt_output) {
@@ -347,7 +345,7 @@ fatal(int f, const char *msg)
 void
 fatalperror(int f, const char *msg)
 {
-	char buf[BUFSIZ];
+	static char buf[BUFSIZ];
 
 	(void) snprintf(buf, sizeof(buf), "%s: %s", msg, strerror(errno));
 	fatal(f, buf);
@@ -722,7 +720,7 @@ printsub(char direction, unsigned char *pointer, int length)
 		    break;
 		}
 		{
-		    char tbuf[32];
+		    static char tbuf[32];
 		    sprintf(tbuf, "%s%s%s%s%s",
 			pointer[2]&MODE_EDIT ? "|EDIT" : "",
 			pointer[2]&MODE_TRAPSIG ? "|TRAPSIG" : "",
@@ -1057,7 +1055,7 @@ void
 printdata(const char *tag, char *ptr, int cnt)
 {
 	int i;
-	char xbuf[30];
+	static char xbuf[30];
 
 	while (cnt) {
 		/* flush net output buffer if no room for new data) */