Adds tty driver to netconsole module. When module is loaded,
creates /dev/netcon0 device and enables support for console=netcon0
kernel cmdline option, causing /dev/console output to be sent to
/dev/netcon0. This allows startup/shutdown script output from
headless platforms to be logged over (secure) network (subject to
availability of specified network device).
To: Matt Mackall <[email protected]>
Signed-off-by: Struan Bartlett <[email protected]>
---
Changes since v1:
* Fixed whitespace mangled by broken mailer
Changes since v2:
* Fixed general mangling by email client (hopefully)
--- a/drivers/net/netconsole.c 2014-03-31 04:40:15.000000000 +0100
+++ b/drivers/net/netconsole.c 2014-04-01 11:58:50.000000000 +0100
@@ -15,6 +15,7 @@
* generic card hooks
* works non-modular
* 2003-09-07 rewritten with netpoll api
+ * 2014-03-31 tty driver by Struan Bartlett
*/
/****************************************************************
@@ -47,6 +48,7 @@
#include <linux/netpoll.h>
#include <linux/inet.h>
#include <linux/configfs.h>
+#include <linux/tty.h>
MODULE_AUTHOR("Maintainer: Matt Mackall <[email protected]>");
MODULE_DESCRIPTION("Console driver for network interfaces");
@@ -728,7 +730,7 @@ static struct notifier_block netconsole_
.notifier_call = netconsole_netdev_event,
};
-static void write_msg(struct console *con, const char *msg, unsigned int len)
+static void _write_msg(const char *msg, unsigned int len)
{
int frag, left;
unsigned long flags;
@@ -764,10 +766,63 @@ static void write_msg(struct console *co
spin_unlock_irqrestore(&target_list_lock, flags);
}
+static void write_msg(struct console *con, const char *msg, unsigned int len)
+{
+ _write_msg(msg, len);
+}
+
+static int netconsole_tty_open(struct tty_struct *tty, struct file *filp)
+{
+ return 0;
+}
+
+static void netconsole_tty_close(struct tty_struct *tty, struct file *filp)
+{
+}
+
+static int netconsole_tty_write(struct tty_struct *tty,
+ const unsigned char *buf, int count)
+{
+ _write_msg(buf, count);
+ return count;
+}
+
+static int netconsole_tty_put_char(struct tty_struct *tty, unsigned char ch)
+{
+ char temp[2] = { ch, 0 };
+ _write_msg(temp, 1);
+ return 1;
+}
+
+static int netconsole_tty_write_room(struct tty_struct *tty)
+{
+ return MAX_PRINT_CHUNK;
+}
+
+static const struct tty_operations netconsole_tty_ops = {
+ .open = netconsole_tty_open,
+ .close = netconsole_tty_close,
+ .write = netconsole_tty_write,
+ .put_char = netconsole_tty_put_char,
+ .write_room = netconsole_tty_write_room,
+};
+
+static struct tty_port netconsole_tty_port;
+static struct tty_driver *netconsole_tty_driver;
+
+static struct tty_driver *netconsole_device(struct console *co, int *index)
+{
+ if (!(co->flags & CON_ENABLED))
+ return NULL;
+ *index = co->index;
+ return netconsole_tty_driver;
+}
+
static struct console netconsole = {
.name = "netcon",
.flags = CON_ENABLED,
.write = write_msg,
+ .device = netconsole_device
};
static int __init init_netconsole(void)
@@ -802,11 +857,39 @@ static int __init init_netconsole(void)
if (err)
goto undonotifier;
+ netconsole_tty_driver = alloc_tty_driver(1);
+ if (!netconsole_tty_driver) {
+ err = -ENOMEM;
+ goto undonotifier;
+ }
+
+ tty_port_init(&netconsole_tty_port);
+
+ netconsole_tty_driver->driver_name = "netcon";
+ netconsole_tty_driver->name = "netcon";
+ netconsole_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
+ netconsole_tty_driver->subtype = SYSTEM_TYPE_TTY;
+ netconsole_tty_driver->init_termios = tty_std_termios;
+ netconsole_tty_driver->init_termios.c_iflag = 0;
+ netconsole_tty_driver->init_termios.c_oflag = 0;
+ netconsole_tty_driver->flags = TTY_DRIVER_REAL_RAW;
+
+ tty_set_operations(netconsole_tty_driver, &netconsole_tty_ops);
+ tty_port_link_device(&netconsole_tty_port, netconsole_tty_driver, 0);
+
+ err = tty_register_driver(netconsole_tty_driver);
+ if (err)
+ goto undotty;
+
register_console(&netconsole);
pr_info("network logging started\n");
return err;
+undotty:
+ put_tty_driver(netconsole_tty_driver);
+ tty_port_destroy(&netconsole_tty_port);
+
undonotifier:
unregister_netdevice_notifier(&netconsole_netdev_notifier);
@@ -830,6 +913,10 @@ static void __exit cleanup_netconsole(vo
{
struct netconsole_target *nt, *tmp;
+ tty_unregister_driver(netconsole_tty_driver);
+ put_tty_driver(netconsole_tty_driver);
+ tty_port_destroy(&netconsole_tty_port);
+
unregister_console(&netconsole);
dynamic_netconsole_exit();
unregister_netdevice_notifier(&netconsole_netdev_notifier);
Struan Bartlett <[email protected]> :
[...]
> --- a/drivers/net/netconsole.c 2014-03-31 04:40:15.000000000 +0100
> +++ b/drivers/net/netconsole.c 2014-04-01 11:58:50.000000000 +0100
> @@ -15,6 +15,7 @@
> * generic card hooks
> * works non-modular
> * 2003-09-07 rewritten with netpoll api
> + * 2014-03-31 tty driver by Struan Bartlett
Useless.
[...]
> +static int netconsole_tty_put_char(struct tty_struct *tty, unsigned char ch)
> +{
> + char temp[2] = { ch, 0 };
> + _write_msg(temp, 1);
Please add an empty line after declaration.
[...]
> @@ -802,11 +857,39 @@ static int __init init_netconsole(void)
> if (err)
> goto undonotifier;
>
> + netconsole_tty_driver = alloc_tty_driver(1);
alloc_tty_driver is said deprecated in include/linux/tty_driver.h
http://marc.info/?l=linux-netdev&m=139629339513575 may delay things a bit.
If so please be patient.
--
Ueimor
On Wed, 2 Apr 2014 19:59:04 +0100
Struan Bartlett <[email protected]> wrote:
> Adds tty driver to netconsole module.
NAK
You don't need to add a tty driver to any console to do this. We have a
ttyprintk driver that works with *any* console today.
Alan