[console] Allow consoles to update the recorded console size

Provide a mechanism for consoles to update the recorded console width
and height, and use this width and height to provide the curses COLS
and LINES variables.

We choose not to use ANSI escape sequences to obtain the width and
height, for two reasons:

- iPXE's model is that all output is sent to all consoles; we could
  therefore end up with multiple consoles reporting conflicting widths
  and heights

- when a serial console is in use, we probably don't want to resize
  the output shown on the BIOS console to match the size of the serial
  console, since it's likely that the serial console is in use only
  for debugging.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/console.c

 /** Current console usage */
 int console_usage = CONSOLE_USAGE_STDOUT;
 
+/** Console width */
+unsigned int console_width = CONSOLE_DEFAULT_WIDTH;
+
+/** Console height */
+unsigned int console_height = CONSOLE_DEFAULT_HEIGHT;
+
 /**
  * Write a single character to each console device
  *
 	struct console_driver *console;
 	int rc;
 
+	/* Reset console width and height */
+	console_set_size ( CONSOLE_DEFAULT_WIDTH, CONSOLE_DEFAULT_HEIGHT );
+
 	/* Try to configure each console */
 	for_each_table_entry ( console, CONSOLES ) {
 		if ( ( console->configure ) &&

src/hci/mucurses/ansi_screen.c

                                unsigned int y, unsigned int x) __nonnull;
 static void ansiscr_putc(struct _curses_screen *scr, chtype c) __nonnull;
 
-unsigned short _COLS = 80;
-unsigned short _LINES = 24;
-
 static unsigned int saved_usage;
 
 static void ansiscr_attrs ( struct _curses_screen *scr, attr_t attrs ) {
 	putchar ( character );
 
 	/* Update expected cursor position */
-	if ( ++(scr->curs_x) == _COLS ) {
+	if ( ++(scr->curs_x) == COLS ) {
 		scr->curs_x = 0;
 		++scr->curs_y;
 	}

src/include/curses.h

 
 #include <stdint.h>
 #include <stdarg.h>
+#include <ipxe/console.h>
 
 /** @file
  *
 } WINDOW;
 
 extern WINDOW _stdscr;
-extern unsigned short _COLS;
-extern unsigned short _LINES;
 
 #define stdscr ( &_stdscr )
-#define COLS _COLS
-#define LINES _LINES
+#define COLS console_width
+#define LINES console_height
 
 #define MUCURSES_BITS( mask, shift ) (( mask ) << (shift))
 #define CPAIR_SHIFT	8

src/include/ipxe/console.h

  */
 #define CONSOLE_EXPLICIT( console ) ( ( 2 * console + 1 ) != 2 )
 
+/** Default console width */
+#define CONSOLE_DEFAULT_WIDTH 80
+
+/** Default console height */
+#define CONSOLE_DEFAULT_HEIGHT 25
+
 extern int console_usage;
+extern unsigned int console_width;
+extern unsigned int console_height;
 
 /**
  * Set console usage
 	return old_usage;
 }
 
+/**
+ * Set console size
+ *
+ * @v width		Width, in characters
+ * @v height		Height, in characters
+ */
+static inline __attribute__ (( always_inline )) void
+console_set_size ( unsigned int width, unsigned int height ) {
+	console_width = width;
+	console_height = height;
+}
+
 extern int iskey ( void );
 extern int getkey ( unsigned long timeout );
 extern int console_configure ( struct console_configuration *config );