Add a config option CONFIG_NULL_TTY_CONSOLE that will have ttynull be
initialized by console_initcall() and selected as a possible console
device.
Signed-off-by: n3rdopolis <bluescreen_avenger@xxxxxxxxxxx>
---
drivers/tty/Kconfig | 18 +++++++++++++++++-
drivers/tty/ttynull.c | 16 +++++++++++++++-
2 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 63a494d36a1f..afe4e7722d4c 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -383,7 +383,23 @@ config NULL_TTY
available or desired.
In order to use this driver, you should redirect the console to this
- TTY, or boot the kernel with console=ttynull.
+ TTY, boot the kernel with console=ttynull, or enable
+ CONFIG_NULL_TTY_CONSOLE.
+
+ If unsure, say N.
+
+config NULL_TTY_CONSOLE
+ bool "Supports /dev/ttynull as a console automatically"
+ depends on NULL_TTY=y && !VT_CONSOLE
+ help
+ Say Y here if you want the NULL TTY to be used as a /dev/console
+ device.
+
+ This is useful for userspace applications that expect a working
+ console device, without changing the kernel boot options, such as a
+ distribuition or environment that historically had CONFIG_VT_CONSOLE
+ enabled, and have now disabled it, but still need /dev/console to be
+ working for userspace applications.
If unsure, say N.
diff --git a/drivers/tty/ttynull.c b/drivers/tty/ttynull.c
index 6b2f7208b564..8ba629ae426b 100644
--- a/drivers/tty/ttynull.c
+++ b/drivers/tty/ttynull.c
@@ -57,6 +57,10 @@ static struct tty_driver *ttynull_device(struct console *c, int *index)
static struct console ttynull_console = {
.name = "ttynull",
.device = ttynull_device,
+#ifdef CONFIG_NULL_TTY_CONSOLE
+ .index = -1,
+ .flags = CON_PRINTBUFFER,
+#endif
};
static int __init ttynull_init(void)
@@ -90,10 +94,20 @@ static int __init ttynull_init(void)
}
ttynull_driver = driver;
- register_console(&ttynull_console);
+ if (!console_is_registered(&ttynull_console))
+ register_console(&ttynull_console);
+
+ return 0;
+}
+#ifdef CONFIG_NULL_TTY_CONSOLE
+static int __init ttynull_register(void)
+{
+ register_console(&ttynull_console);
return 0;
}
+console_initcall(ttynull_register);
+#endif
static void __exit ttynull_exit(void)
{
--
2.45.2
