Re: [Xen-devel] [PATCH for-4.12 RFC] xen/console: Handle NUL character in buffer sent via CONSOLEIO_write

[Ian Jackson <ian.jackson@xxxxxxxxxx>]

Julien Grall writes ("Re: [PATCH for-4.12 RFC] xen/console: Handle NUL 
character in buffer sent via CONSOLEIO_write"):
> On 04/03/2019 11:21, George Dunlap wrote:
> > zsh is sending a NUL character to the console in the middle of the
> > buffer?  Why would it do that?  Is that defined behavior, or does it
> > just happen to work because Xen is the first console device to act
> > strange as a result?
>
> I have no idea why new version of ZSH is adding '\0' in the
> buffer. But, to be honest, it does not matter to know it.
> 
> What matters is an application using the POSIX call write() is free
> to put a '\0' in the middle of the stream. It is up to the reader
> (i.e screen/gdb...) to decide how to interpret the characters.

Nuls are perfectly legitimate in terminal streams.  They used to be
used for padding for slow terminals, for example.  See terminfo(5)
section `Delays and Padding', or search for the pcre `\bpad'.

NB that Xen does not control the ultimate kind of terminal.  The
terminal is whatever is ultimately connected (via a series of physical
and logical links) to the dom0's console interface.

There is no bug in zsh here.

Ian.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel