Close master pty on DCD drop if not CLOCAL

ttynvt.c

@@ -69,8 +69,9 @@ typedef struct {
 
     struct termios  tio;
 
-    int             cmcr;
+    int             cmcr;       /* Commanded by ioctl */
-    volatile int    smcr;
+    volatile int    smcr;       /* Status from modem */
+    int             smcr_last;
 
     volatile int    pollin;
     volatile int    error;
@@ -223,6 +224,22 @@ static void _update_notify(ttynvt_t * tty, struct fuse_pollhandle *ph)
         fuse_pollhandle_destroy(tmp_ph);
 }
 
+static int _net_read_check_exit(ttynvt_t * tty)
+{
+    if ((tty->tio.c_cflag & CLOCAL) == 0 &&
+        (tty->smcr_last & TIOCM_CD) != 0 && (tty->smcr & TIOCM_CD) == 0)
+    {
+        /* CLOCAL is not set (i.e. do not ignore modem control lines) AND
+         * DCD dropped */
+        DBG("GOT DCD DROP\n");
+        close(tty->fds[FD_MASTER].fd);
+        tty->fds[FD_MASTER].fd = -1;
+        return 1;
+    }
+
+    return 0;
+}
+
 static void    *_read_net(void *arg)
 {
     ttynvt_t       *tty = (ttynvt_t *) arg;
@@ -280,6 +297,8 @@ static void    *_read_net(void *arg)
                 }
                 tty->net_cnt = 0;
             }
+            if (_net_read_check_exit(tty))
+                break;
         }
 
         if (tty->fds[FD_MASTER].revents & POLLIN)
@@ -419,6 +438,7 @@ static void _modem_status_cb(void *cctx, int status)
         mcr |= TIOCM_DSR;
 
     pthread_mutex_lock(&tty->tty_lock);
+    tty->smcr_last = tty->smcr;
     tty->smcr = mcr;
     pthread_mutex_unlock(&tty->tty_lock);
 }