Re: [PATCH 2 of 2] netconsole: add write-only tty driver

> This allows userspace to output to netconsole via the /dev/console device, > which is very useful to see initscript output, for example. There is only one > netconsole TTY device, and TTY output goes to all receivers specified for > console output. > > Input via /dev/console is still not implemented, however. > > Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com> > > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c > --- a/drivers/net/netconsole.c > +++ b/drivers/net/netconsole.c > @@ -43,6 +43,7 @@ > #include <linux/netpoll.h> > #include <linux/inet.h> > #include <linux/configfs.h> > +#include <linux/tty.h> > > MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>"); > MODULE_DESCRIPTION("Console driver for network interfaces"); > @@ -98,6 +99,8 @@ struct netconsole_target { > int enabled; > struct netpoll np; > }; > + > +static struct tty_driver *netconsole_tty_driver; > > #ifdef CONFIG_NETCONSOLE_DYNAMIC > > @@ -728,15 +731,74 @@ static void netconsole_write_msg(const c > spin_unlock_irqrestore(&target_list_lock, flags); > } > > +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) > +{ > + netconsole_write_msg(buf, count); > + return count; > +} > + > +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, > + .write_room = netconsole_tty_write_room, > +}; > + > +static int __init netconsole_tty_init(void) > +{ > + netconsole_tty_driver = alloc_tty_driver(1); > + if (!netconsole_tty_driver) > + return -ENOMEM; > + > + netconsole_tty_driver->owner = THIS_MODULE; > + netconsole_tty_driver->driver_name = "netcon"; > + netconsole_tty_driver->name = "netcon"; > + netconsole_tty_driver->minor_start = 0; > + netconsole_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; > + netconsole_tty_driver->init_termios = tty_std_termios; > + netconsole_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL; > + netconsole_tty_driver->init_termios.c_ispeed = 9600; > + netconsole_tty_driver->init_termios.c_ospeed = 9600; > + netconsole_tty_driver->flags = TTY_DRIVER_REAL_RAW; > + tty_set_operations(netconsole_tty_driver, &netconsole_tty_ops); > + > + if (tty_register_driver(netconsole_tty_driver)) > + printk(KERN_ERR "Couldn't register netconsole tty driver\n"); > + > + return 0; > +} > +device_initcall(netconsole_tty_init);