It turns out that the following:

  close(1);
  close(2);
  x = open(ctermid(NULL), O_RDWR|O_NONBLOCK);
  close(0)
on a tty causes select() to return an exception for descriptor x !
This is the case in RELENG_2_2, but not in 2.2.2.  I'm not sure why.
Instead of doing the x=open() and close(0), we just do x=0 now.
Problem pointed out by: Greg Lehey <grog@lemis.com>
                        Tomi Vainio <tomppa@fidata.fi>

2 files changed, 5 insertions, 17 deletions

diff --git a/usr.sbin/ppp/main.c b/usr.sbin/ppp/main.c
index bc71573..ea257a5 100644
--- a/usr.sbin/ppp/main.c
+++ b/usr.sbin/ppp/main.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: main.c,v 1.78 1997/09/16 23:15:13 brian Exp $
+ * $Id: main.c,v 1.79 1997/09/18 00:15:25 brian Exp $
  *
  *	TODO:
  *		o Add commands for traffic summary, version display, etc.
@@ -711,7 +711,6 @@ DoLoop()
     if (OpenModem(mode) < 0)
       return;
     LogPrintf(LogPHASE, "Packet mode enabled\n");
-    close(0);
     PacketMode();
   } else if (mode & MODE_DEDICATED) {
     if (modem < 0)
diff --git a/usr.sbin/ppp/modem.c b/usr.sbin/ppp/modem.c
index 35f52b2..9cd0098 100644
--- a/usr.sbin/ppp/modem.c
+++ b/usr.sbin/ppp/modem.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: modem.c,v 1.52 1997/09/16 23:15:14 brian Exp $
+ * $Id: modem.c,v 1.53 1997/09/18 00:15:25 brian Exp $
  *
  *  TODO:
  */
@@ -442,20 +442,9 @@ OpenModem(int mode)
     LogPrintf(LogDEBUG, "OpenModem: Modem is already open!\n");
     /* We're going back into "term" mode */
   else if (mode & MODE_DIRECT) {
-    if (isatty(0)) {
-      char *dev;
-      modem = open(dev = ctermid(NULL), O_RDWR | O_NONBLOCK);
-      if (modem < 0) {
-	LogPrintf(LogERROR, "OpenModem(direct) failed: %s: %s\n",
-		  dev, strerror(errno));
-	return (-1);
-      }
-      LogPrintf(LogDEBUG, "OpenModem(direct): Modem is a tty\n");
-    } else {
-      /* must be a tcp connection */
-      LogPrintf(LogDEBUG, "OpenModem(direct): Modem is not a tty\n");
-      return modem = dup(0);
-    }
+    LogPrintf(LogDEBUG, "OpenModem(direct): Modem is %sa tty\n",
+              isatty(0) ? "" : "not ");
+    return modem = 0;
   } else {
     if (strncmp(VarDevice, "/dev/", 5) == 0) {
       if ((res = uu_lock(VarBaseDevice)) != UU_LOCK_OK) {