1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/kernel.h> |
3 | #include <linux/init.h> |
4 | #include <linux/console.h> |
5 | |
6 | #include "chan_user.h" |
7 | |
8 | /* ----------------------------------------------------------------------------- */ |
9 | /* trivial console driver -- simply dump everything to stderr */ |
10 | |
11 | /* |
12 | * Don't register by default -- as this registers very early in the |
13 | * boot process it becomes the default console. |
14 | * |
15 | * Initialized at init time. |
16 | */ |
17 | static int use_stderr_console = 0; |
18 | |
19 | static void stderr_console_write(struct console *console, const char *string, |
20 | unsigned len) |
21 | { |
22 | generic_write(fd: 2 /* stderr */, buf: string, n: len, NULL); |
23 | } |
24 | |
25 | static struct console stderr_console = { |
26 | .name = "stderr" , |
27 | .write = stderr_console_write, |
28 | .flags = CON_PRINTBUFFER, |
29 | }; |
30 | |
31 | static int __init stderr_console_init(void) |
32 | { |
33 | if (use_stderr_console) |
34 | register_console(&stderr_console); |
35 | return 0; |
36 | } |
37 | console_initcall(stderr_console_init); |
38 | |
39 | static int stderr_setup(char *str) |
40 | { |
41 | if (!str) |
42 | return 0; |
43 | use_stderr_console = simple_strtoul(str,&str,0); |
44 | return 1; |
45 | } |
46 | __setup("stderr=" , stderr_setup); |
47 | |
48 | /* The previous behavior of not unregistering led to /dev/console being |
49 | * impossible to open. My FC5 filesystem started having init die, and the |
50 | * system panicing because of this. Unregistering causes the real |
51 | * console to become the default console, and /dev/console can then be |
52 | * opened. Making this an initcall makes this happen late enough that |
53 | * there is no added value in dumping everything to stderr, and the |
54 | * normal console is good enough to show you all available output. |
55 | */ |
56 | static int __init unregister_stderr(void) |
57 | { |
58 | unregister_console(&stderr_console); |
59 | |
60 | return 0; |
61 | } |
62 | |
63 | __initcall(unregister_stderr); |
64 | |