Re: Printing the messages through printk while using Xwindows.

From: Tigran Aivazian (tigran@veritas.com)
Date: Fri Jul 28 2000 - 14:46:52 EST


before people blame me for corrupting their filesystems, here is a hint:

registering a filesystem doesn't give you moral right to attempt to mount
it :)

seriously though, FS_SINGLE filesystems must be kern_mount()'d before they
can be user-mounted so if you try to usermount the filesystem below you
will get an oops for a well-known reason (nothing to do with terminals or
X :) (and after the oops you won't be able to umount any filesystems so
fsck will be inevitable)

Regards,
Tigran

 On Fri, 28 Jul 2000, Tigran Aivazian wrote:

> On Fri, 28 Jul 2000, Russell King wrote:
> > Therefore, its fine if you've got one of the few cards that fbcon
> > works with. Otherwise you're using vgacon, and it doesn't work.
>
> It does actually work on plain vga without any fb support at all. Try it
> and see. Here is a little ready-to-compile module for you to try.
>
> Regards,
> Tigran
>
> #define __KERNEL__
> #define MODULE
>
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/sched.h>
>
> print_string(char *str)
> {
> struct tty_struct *tty = current->tty;
>
> (*tty->driver.write)(tty, 0, str, strlen(str));
> (*tty->driver.write)(tty, 0, "\015\012", 2);
> }
>
>
> static struct super_block *
> single_read_super(struct super_block *s, void *data, int silent)
> {
> char buf[100];
> sprintf(buf, "comm=%s\n", current->comm);
> print_string(buf);
> return NULL;
> }
>
> static DECLARE_FSTYPE(single_fs_type, "single", single_read_super, FS_SINGLE);
>
> static int __init init_single_fs(void)
> {
> char buf[100];
> int ret = register_filesystem(&single_fs_type);
>
> printk(KERN_ERR "init_single_fs(): ret = %d\n", ret);
> sprintf(buf, "comm=%s\n", current->comm);
> print_string(buf);
> return ret;
> }
>
> static void __exit exit_single_fs(void)
> {
> char buf[100];
> sprintf(buf, "comm=%s\n", current->comm);
> print_string(buf);
> unregister_filesystem(&single_fs_type);
> }
>
> module_init(init_single_fs);
> module_exit(exit_single_fs);
>
>

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