1#include <linux/kernel.h>
2#include <linux/init.h>
3#include <linux/console.h>
4
5#include "chan_user.h"
6
7/* ----------------------------------------------------------------------------- */
8/* trivial console driver -- simply dump everything to stderr                    */
9
10/*
11 * Don't register by default -- as this registers very early in the
12 * boot process it becomes the default console.
13 *
14 * Initialized at init time.
15 */
16static int use_stderr_console = 0;
17
18static void stderr_console_write(struct console *console, const char *string,
19				 unsigned len)
20{
21	generic_write(2 /* stderr */, string, len, NULL);
22}
23
24static struct console stderr_console = {
25	.name		= "stderr",
26	.write		= stderr_console_write,
27	.flags		= CON_PRINTBUFFER,
28};
29
30static int __init stderr_console_init(void)
31{
32	if (use_stderr_console)
33		register_console(&stderr_console);
34	return 0;
35}
36console_initcall(stderr_console_init);
37
38static int stderr_setup(char *str)
39{
40	if (!str)
41		return 0;
42	use_stderr_console = simple_strtoul(str,&str,0);
43	return 1;
44}
45__setup("stderr=", stderr_setup);
46
47/* The previous behavior of not unregistering led to /dev/console being
48 * impossible to open.  My FC5 filesystem started having init die, and the
49 * system panicing because of this.  Unregistering causes the real
50 * console to become the default console, and /dev/console can then be
51 * opened.  Making this an initcall makes this happen late enough that
52 * there is no added value in dumping everything to stderr, and the
53 * normal console is good enough to show you all available output.
54 */
55static int __init unregister_stderr(void)
56{
57	unregister_console(&stderr_console);
58
59	return 0;
60}
61
62__initcall(unregister_stderr);
63