examples/nxterm: add PTY-backed keyboard console

examples/nxterm/CMakeLists.txt

@@ -33,4 +33,7 @@ if(CONFIG_EXAMPLES_NXTERM)
     SRCS
     nxterm_main.c)
   target_sources(apps PRIVATE nxterm_toolbar.c nxterm_wndo.c nxterm_listener.c)
+  if(CONFIG_EXAMPLES_NXTERM_PTYCONSOLE)
+    target_sources(apps PRIVATE nxterm_pty.c)
+  endif()
 endif()

examples/nxterm/Kconfig

@@ -64,6 +64,43 @@ config EXAMPLES_NXTERM_FULLSCREEN
 		Size the NXTerm window to cover the complete display instead of
 		centering it at three quarters of the display size.
 
+config EXAMPLES_NXTERM_PTYCONSOLE
+	bool "PTY-backed keyboard console"
+	default n
+	depends on PSEUDOTERM && INPUT_KEYBOARD
+	depends on !INPUT_KEYBOARD_BYTESTREAM
+	depends on !NSH_ALTCONDEV && !NSH_USBKBD
+	---help---
+		Route NSH through a pseudo-terminal and bridge an event-mode keyboard
+		to the terminal master.  This gives NXTerm a real TTY, translates
+		NuttX keyboard special-key codes to VT100 input, and permits terminal
+		generated signals such as Ctrl-C and Ctrl-Z.
+
+config EXAMPLES_NXTERM_NSH_FALLBACK
+	bool "Fall back to serial NSH"
+	default n
+	depends on NSH_CONSOLE
+	---help---
+		Run NSH on the original system console if NX or NXTerm initialization
+		fails.  This is useful on framebuffer systems where display startup
+		failures would otherwise leave no interactive console.
+
+config EXAMPLES_NXTERM_STARTUP_TIMEOUT
+	int "NX startup timeout"
+	default 5
+	range 1 60
+	depends on EXAMPLES_NXTERM_NSH_FALLBACK
+	---help---
+		Number of seconds to wait for the NX server to accept the client
+		connection before falling back to NSH on the system console.
+
+config EXAMPLES_NXTERM_KBDDEV
+	string "Keyboard device"
+	default "/dev/kbda"
+	depends on EXAMPLES_NXTERM_PTYCONSOLE
+	---help---
+		Path of the keyboard event device bridged to the pseudo-terminal.
+
 config EXAMPLES_NXTERM_TOOLBAR_HEIGHT
 	int "Toolbar height"
 	default 16

examples/nxterm/Makefile

@@ -25,6 +25,11 @@ include $(APPDIR)/Make.defs
 # NuttX NX Console Example.
 
 CSRCS = nxterm_toolbar.c nxterm_wndo.c nxterm_listener.c
+
+ifeq ($(CONFIG_EXAMPLES_NXTERM_PTYCONSOLE),y)
+CSRCS += nxterm_pty.c
+endif
+
 MAINSRC = nxterm_main.c
 
 # NX built-in application info

examples/nxterm/nxterm_internal.h

@@ -219,6 +219,9 @@ struct nxterm_state_s
 {
   volatile bool          haveres;   /* True: Have screen resolution */
   volatile bool          connected; /* True: Connected to server */
+#ifdef CONFIG_EXAMPLES_NXTERM_NSH_FALLBACK
+  volatile bool          servererr; /* True: Server connection failed */
+#endif
   sem_t                  eventsem;  /* Control waiting for display events */
   pid_t                  pid;       /* Console task ID */
   NXHANDLE               hnx;       /* The connection handler */
@@ -254,4 +257,8 @@ extern const struct nx_callback_s g_nxtoolcb;
 
 FAR void *nxterm_listener(FAR void *arg);
 
+#ifdef CONFIG_EXAMPLES_NXTERM_PTYCONSOLE
+int nxterm_pty_redirect(int nxtermfd);
+#endif
+
 #endif /* __APPS_EXAMPLES_NXTERM_NXTERM_INTERNAL_H */

examples/nxterm/nxterm_listener.c

@@ -48,7 +48,7 @@ FAR void *nxterm_listener(FAR void *arg)
 
   /* Process events forever */
 
-  for (;;)
+  for (; ; )
     {
       /* Handle the next event.  If we were configured blocking, then
        * we will stay right here until the next event is received.  Since
@@ -66,7 +66,13 @@ FAR void *nxterm_listener(FAR void *arg)
            */
 
           printf("nxterm_listener: Lost server connection: %d\n", errno);
+#ifdef CONFIG_EXAMPLES_NXTERM_NSH_FALLBACK
+          g_nxterm_vars.servererr = true;
+          sem_post(&g_nxterm_vars.eventsem);
+          return NULL;
+#else
           exit(EXIT_FAILURE);
+#endif
         }
 
       /* If we received a message, we must be connected */

examples/nxterm/nxterm_main.c

@@ -33,6 +33,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <time.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
@@ -76,6 +77,9 @@ struct nxterm_state_s g_nxterm_vars;
 static int nxterm_initialize(void)
 {
   struct sched_param param;
+#ifdef CONFIG_EXAMPLES_NXTERM_NSH_FALLBACK
+  struct timespec abstime;
+#endif
   pthread_t thread;
   int ret;
 
@@ -142,6 +146,51 @@ static int nxterm_initialize(void)
 
       /* Don't return until we are connected to the server */
 
+#ifdef CONFIG_EXAMPLES_NXTERM_NSH_FALLBACK
+      pthread_detach(thread);
+
+      ret = clock_gettime(CLOCK_REALTIME, &abstime);
+      if (ret < 0)
+        {
+          printf("nxterm_initialize: clock_gettime failed: %d\n", errno);
+          nx_disconnect(g_nxterm_vars.hnx);
+          g_nxterm_vars.hnx = NULL;
+          return ERROR;
+        }
+
+      abstime.tv_sec += CONFIG_EXAMPLES_NXTERM_STARTUP_TIMEOUT;
+      while (!g_nxterm_vars.connected && !g_nxterm_vars.servererr)
+        {
+          /* Wait for the listener thread to report either a connection or
+           * a server error.  The server starts asynchronously, so a timeout
+           * is also needed when display initialization fails before it can
+           * send the first event.
+           */
+
+          ret = sem_timedwait(&g_nxterm_vars.eventsem, &abstime);
+          if (ret < 0 && errno != EINTR)
+            {
+              if (errno == ETIMEDOUT)
+                {
+                  printf("nxterm_initialize: NX startup timed out\n");
+                }
+              else
+                {
+                  printf("nxterm_initialize: sem_timedwait failed: %d\n",
+                         errno);
+                }
+
+              g_nxterm_vars.servererr = true;
+            }
+        }
+
+      if (!g_nxterm_vars.connected)
+        {
+          nx_disconnect(g_nxterm_vars.hnx);
+          g_nxterm_vars.hnx = NULL;
+          return ERROR;
+        }
+#else
       while (!g_nxterm_vars.connected)
         {
           /* Wait for the listener thread to wake us up when we really
@@ -150,6 +199,7 @@ static int nxterm_initialize(void)
 
           sem_wait(&g_nxterm_vars.eventsem);
         }
+#endif
     }
   else
     {
@@ -376,12 +426,22 @@ int main(int argc, FAR char *argv[])
   fflush(stdout);
   fflush(stderr);
 
+#ifdef CONFIG_EXAMPLES_NXTERM_PTYCONSOLE
+  ret = nxterm_pty_redirect(fd);
+  if (ret < 0)
+    {
+      printf("nxterm_main: PTY console setup failed: %d\n", -ret);
+      close(fd);
+      goto errout_with_driver;
+    }
+#else
   dup2(fd, 1);
   dup2(fd, 2);
 
   /* And we can close our original driver file descriptor */
 
   close(fd);
+#endif
 
   /* And start the console task.  It will inherit stdin, stdout, and stderr
    * from this task.
@@ -408,5 +468,10 @@ int main(int argc, FAR char *argv[])
   nx_disconnect(g_nxterm_vars.hnx);
 
 errout:
+#ifdef CONFIG_EXAMPLES_NXTERM_NSH_FALLBACK
+  printf("nxterm_main: Falling back to the system console\n");
+  return nsh_consolemain(argc, argv);
+#else
   return EXIT_FAILURE;
+#endif
 }