[PATCH] Ensure serial device exists prior to use

[Jeremy Katz]

We shouldn't try to use the serial terminal if the user hasn't properly
configured it yet.  This patch (against current CVS) makes it so ensures
that we have set up a serial port prior to switching to a serial
terminal.

Index: ChangeLog
===================================================================
RCS file: /cvsroot/grub/grub/ChangeLog,v
retrieving revision 1.428
diff -u -r1.428 ChangeLog
--- ChangeLog   2001/08/08 05:17:20     1.428
+++ ChangeLog   2001/08/08 05:46:58
@@ -1,3 +1,13 @@
+2001-08-08  Jeremy Katz  <address@hidden>
+
+       * grub/asmstub.c, stage2/serial.c, stage2/serial.h:
+       add serial_exists() function to ensure that serial port is set up
+       prior to use
+
+       * stage2/builtins.c:
+       use serial_exists when serial terminal is selected or fallback to
+       previous terminal definition
+ 
 2001-08-08  OKUJI Yoshinori  <address@hidden>
 
        * util/grub-md5-crypt.in: Prefix backquotes with backslashes in
Index: grub/asmstub.c
===================================================================
RCS file: /cvsroot/grub/grub/grub/asmstub.c,v
retrieving revision 1.70
diff -u -r1.70 asmstub.c
--- grub/asmstub.c      2001/05/03 08:34:56     1.70
+++ grub/asmstub.c      2001/08/08 05:46:59
@@ -1026,6 +1026,21 @@
   return 0;
 }
 
+/* Do we have a serial port set up?  In the grub shell, we should check
+   if the fd is open */
+int serial_exists(void) 
+{
+  grub_printf("serial_fd is %d\n", serial_fd);
+  if (serial_fd >= 0) 
+    {
+      return 1;
+    }
+  else
+    {
+      return 0;
+    }
+}
+
 /* Initialize a serial device. In the grub shell, PORT is unused.  */
 int
 serial_init (unsigned short port, unsigned int speed,
Index: stage2/builtins.c
===================================================================
RCS file: /cvsroot/grub/grub/stage2/builtins.c,v
retrieving revision 1.112
diff -u -r1.112 builtins.c
--- stage2/builtins.c   2001/06/21 23:15:02     1.112
+++ stage2/builtins.c   2001/08/08 05:47:02
@@ -3914,9 +3914,18 @@
 #ifdef SUPPORT_SERIAL
       else if (grub_memcmp (arg, "serial", sizeof ("serial") - 1) == 0)
        {
-         terminal |= TERMINAL_SERIAL;
-         if (! default_terminal)
-           default_terminal = TERMINAL_SERIAL;
+         if (serial_exists())
+           {
+             terminal |= TERMINAL_SERIAL;
+             if (! default_terminal)
+               default_terminal = TERMINAL_SERIAL;
+           }
+         else 
+           {
+             terminal = saved_terminal;
+             grub_printf("No serial device configured.\n");
+             grub_printf("Resetting to previous terminal configuration.\n");
+           }
        }
 #endif /* SUPPORT_SERIAL */
       else
Index: stage2/serial.c
===================================================================
RCS file: /cvsroot/grub/grub/stage2/serial.c,v
retrieving revision 1.3
diff -u -r1.3 serial.c
--- stage2/serial.c     2000/08/26 17:36:07     1.3
+++ stage2/serial.c     2001/08/08 05:47:02
@@ -31,7 +31,7 @@
 };
 
 /* Store the port number of a serial unit.  */
-static unsigned short serial_port;
+static unsigned short serial_port = -1;
 
 /* The table which lists common configurations.  */
 static struct divisor divisor_tab[] =
@@ -100,6 +100,15 @@
       return;
 
   outb (serial_port + UART_TX, c);
+}
+
+/* do we have a serial port set up? */
+int
+serial_exists (void)
+{
+  if (serial_port == -1)
+    return 0;
+  return 1;
 }
 
 /* Return the port number for the UNITth serial device.  */
Index: stage2/serial.h
===================================================================
RCS file: /cvsroot/grub/grub/stage2/serial.h,v
retrieving revision 1.5
diff -u -r1.5 serial.h
--- stage2/serial.h     2000/08/26 17:36:07     1.5
+++ stage2/serial.h     2001/08/08 05:47:02
@@ -93,6 +93,9 @@
 int serial_init (unsigned short port, unsigned int speed,
                 int word_len, int parity, int stop_bit_len);
 
+/* Do we have a serial port set up? */
+int serial_exists (void);
+
 #ifdef GRUB_UTIL
 /* Set the file name of a serial device (or a pty device). This is a
    function specific to the grub shell.  */