Re: [PATCH] Console: fall back to /dev/null when no console is availlable

[Denis Vlasenko]

> More computing sins are committed in the name of efficiency (without
> necessarily achieving it) than for any other single reason - including
> blind stupidity.
> -- W. A. Wulf 
> 
> Some userspace applications rely on the assumption that fd's 0, 1 and
> 2 are always open and function as raw stdin, stdout and stderr,
> respectively.
> 
> With no console registered, init get's called without those fd's
> already open.  Arguably, init should know better, handle that case and
> fix things before forking other processed.  But what about
> init=/bin/bash?  Ok, bash could be fixed as well, as could...
> 
> Instead, this patch opens /dev/null when /dev/console doesn't work.
> It swallows all output and doesn't give much input, but programs can
> handle that just fine.
> 
> Signed-off-by: Jцrn Engel <joern@xxxxxxxxxxxxxxxxxxxx>
> ---
> 
>  main.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletion(-)
> 
> --- linux-2.6.8cow/init/main.c~console	2004-10-05 20:46:40.000000000 +0200
> +++ linux-2.6.8cow/init/main.c	2004-10-05 20:46:08.000000000 +0200
> @@ -695,8 +695,11 @@
>  	system_state = SYSTEM_RUNNING;
>  	numa_default_policy();
>  
> -	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
> +	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) {
>  		printk("Warning: unable to open an initial console.\n");
> +		if (open("/dev/null", O_RDWR, 0) == 0)
> +			printk("         Falling back to /dev/null.\n");
> +	}

What will happen if /dev is totally empty?
--
vda

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