stdout to console

[Jonathan Neuschäfer]

On Mon, Apr 23, 2012 at 03:45:00PM +0530, Arun KS wrote:
> Hello Guys,
> 
> We all know that when an application writes to stdout, data ends up in
> the console.
> 
> Okey so if I m on my development board and if I run an app, all the
> prints comes to the console (eg /dev/ttyS0).
> If I m on any server using ssh and all apps prints comes on my putty
> (eg through /dev/pts/176).
> 
> Where is the code which maps fd 1 to the console in kernel?
> If you guys have any pointers, please share.
> 
> While opening a device (for eg /dev/something), the vfs calls that
> drivers, whose major and minor number matches.
> But in case of stdout, how vfs resolves the write to the fd 1 and send
> it to the corresponding console driver?
> 
> Thanks,
> Arun

It's in init/main.c, around line 823.

"strace" is a useful tool for trying to figure out what exactly a user
space process does.

The man pages of various system calls (open, fork, exec, dup, etc.) may
also provide valuable information.


Thanks,
	Jonathan Neuschäfer