Re: [PATCH v10 1/2] cmdline: handle EOF in cmdline_poll

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 30 Jan 2023 22:12:42 +0000
Ferruh Yigit <ferruh.yigit@amd.com> wrote:

> On 1/30/2023 8:09 PM, Stephen Hemminger wrote:
> > If end of file is reached on input, then cmdline_read_char()
> > will return 0. The problem is that cmdline_poll() was not checking
> > for this and would continue and not return the status.
> > 
> > Fixes: 9251cd97a6be ("cmdline: add internal wrappers for character input")
> > Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> > ---
> >  lib/cmdline/cmdline.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/lib/cmdline/cmdline.c b/lib/cmdline/cmdline.c
> > index e1009ba4c413..de41406d61e0 100644
> > --- a/lib/cmdline/cmdline.c
> > +++ b/lib/cmdline/cmdline.c
> > @@ -194,7 +194,7 @@ cmdline_poll(struct cmdline *cl)
> >  	else if (status > 0) {
> >  		c = -1;
> >  		read_status = cmdline_read_char(cl, &c);
> > -		if (read_status < 0)
> > +		if (read_status <= 0)
> >  			return read_status;  
> 
> According API doc it will be wrong to return '0', which imply 'RDLINE_INIT'.

The API doc is a mess. It says function returns things enum that is only
defined in cmdline_private.h. Therefore no application could safely depend
on it.

End of File is not an error in most API's.