drivers/serial: Integrate new Ctrl-C logic with the ISIG flag in the termios c_lflag. Fix several compiler errors resulting from recently flurry of renaming.

drivers/serial/Kconfig

@@ -19,26 +19,6 @@ config SERIAL_CONSOLE
 	bool
 	default n
 
-config TTY_SIGKILL
-	bool "Support SIGKILL"
-	default n
-	select SIG_DEFAULT
-	depends on !DISABLE_SIGNALS
-	---help---
-		Whether support Ctrl-c/x event
-
-config TTY_SIGKILL_CHAR
-	int "Serial parse SIGKILL characters"
-	default 3 if SERIAL_CONSOLE
-	default 4 if !SERIAL_CONSOLE
-	depends on SIG_SIGKILL
-	---help---
-		Use ASCII 3 (Ctrl-c) or 4 (ctrl-d) inputs to determine whether to
-		send a SIGKILL event.  Other characters may also be selected.
-
-		REVISIT:  Traditionally Ctrl-C would generate SIGINT.  Ctrl-D is the
-		End-of-File character that should close the stream.
-
 menuconfig 16550_UART
 	bool "16550 UART Chip support"
 	default n
@@ -151,6 +131,28 @@ config SERIAL_TERMIOS
 		If this is not defined, then the terminal settings (baud, parity, etc).
 		are not configurable at runtime; serial streams cannot be flushed, etc..
 
+config TTY_SIGKILL
+	bool "Support SIGKILL"
+	default n
+	select SIG_DEFAULT
+	depends on !DISABLE_SIGNALS && SERIAL_TERMIOS
+	---help---
+		Whether support Ctrl-c/x event.  Enabled automatically for console devices.
+		May be enabled for other serial devices using the ISIG bit in the Termios
+		c_lflag.
+
+config TTY_SIGKILL_CHAR
+	int "Serial parse SIGKILL characters"
+	default 3 if SERIAL_CONSOLE
+	default 4 if !SERIAL_CONSOLE
+	depends on TTY_SIGKILL
+	---help---
+		Use ASCII 3 (Ctrl-c) or 4 (ctrl-d) inputs to determine whether to
+		send a SIGKILL event.  Other characters may also be selected.
+
+		REVISIT:  Traditionally Ctrl-C would generate SIGINT.  Ctrl-D is the
+		End-of-File character that should close the stream.
+
 #
 # Serial console selection
 #

drivers/serial/serial.c

@@ -1372,22 +1372,22 @@ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
             break;
 #endif
 
-#ifdef CONFIG_TTY_SIGKILL_CHAR
+#ifdef CONFIG_TTY_SIGKILL
           /* Make the given terminal the controlling terminal of the calling process */
 
           case TIOCSCTTY:
             {
-              /* REVISIT:  This only applies to console devices (TTYs).  In
-               * reality, this feature should be controlled by TERMIOS ISIG
-               * c_lflag setting.
+              /* Check if the ISIG flag is set in the termios c_lflag to enable
+               * this feature.  This flag is set automatically for a serial console
+               * device.
                */
 
-             if (dev->isconsole)
+             if ((dev->tc_lflag & ISIG) != 0)
                {
                   /* Save the PID of the recipient of the SIGKILL signal. */
 
                   dev->pid = (pid_t)arg;
-                  DEBUGASSERT((unsigned long)dev->pid = arg);
+                  DEBUGASSERT((unsigned long)(dev->pid) == arg);
                }
             }
             break;
@@ -1435,6 +1435,17 @@ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
               dev->tc_iflag = termiosp->c_iflag;
               dev->tc_oflag = termiosp->c_oflag;
               dev->tc_lflag = termiosp->c_lflag;
+
+#ifdef CONFIG_TTY_SIGKILL
+              /* If the ISIG flag has been cleared in c_lflag, then un-
+               * register the controlling terminal.
+               */
+
+              if ((dev->tc_lflag & ISIG) == 0)
+                {
+                  dev->pid = (pid_t)-1;
+                }
+#endif
             }
             break;
         }
@@ -1600,10 +1611,17 @@ errout:
 
 int uart_register(FAR const char *path, FAR uart_dev_t *dev)
 {
-#ifdef CONFIG_TTY_SIGKILL_CHAR
+#ifdef CONFIG_TTY_SIGKILL
   /* Initialize  of the task that will receive SIGKILL signals. */
 
-  dev->pid = -1;
+  dev->pid = (pid_t)-1;
+
+  /* If this UART is a serial console, then enable signals by default */
+
+  if (dev->isconsole)
+    {
+      dev->tc_lflag |= ISIG;
+    }
 #endif
 
   /* Initialize semaphores */

drivers/serial/serial_io.c

@@ -206,8 +206,8 @@ void uart_recvchars(FAR uart_dev_t *dev)
 
       if (dev->pid >= 0 && ch == CONFIG_TTY_SIGKILL_CHAR)
         {
-          /* Yes.. not the the kill is needed and do not put the character into
-           * the Rx buffer.  It should not be read as normal data.
+          /* Yes.. note that the kill is needed and do not put the character
+           * into the Rx buffer.  It should not be read as normal data.
            */
 
           needkill = true;

include/nuttx/serial/serial.h

@@ -286,10 +286,9 @@ struct uart_dev_s
   tcflag_t             tc_iflag;     /* Input modes */
   tcflag_t             tc_oflag;     /* Output modes */
   tcflag_t             tc_lflag;     /* Local modes */
+#ifdef CONFIG_TTY_SIGKILL
+  pid_t                pid;          /* Thread PID to receive SIGKILL signals (-1 if none) */
 #endif
-
-#ifdef CONFIG_SERIAL_SIGKILL_CHAR
-  pid_t                 pid;         /* Thread PID to receive SIGKILL signals (-1 if none) */
 #endif
 
   /* Semaphores */