Re: problems with daily images

[Samuel Thibault]

Jessica Clarke, le dim. 24 janv. 2021 00:59:23 +0000, a ecrit:
> On 24 Jan 2021, at 00:41, Damien Zammit <damien@zamaudio.com> wrote:
> >    (void)ioctl(f, TIOCFLUSH, (char *) 0);
> 
> It seems only QNX ends up setting POSIX for some inexplicable reason.
> Since Hurd defines TIOCFLUSH, it ends up calling this line. But
> TIOCFLUSH takes an int * pointing at flags, so when converting the
> ioctl into an RPC it'll dereference the null pointer and segfault. It
> should either pass a pointer to an int with the right flags or just use
> tcflush like a sane program.
> 
> NB: Neither Linux nor FreeBSD define/implement TIOCFLUSH.

This interface seems awfully confused. Looking at occurrences in Debian
I can see all cases:

- passing the address of int x = FREAD (as apparently expected...)
- passing the address of int x = 0 (as apparently correctly interpreted
  as FREAD|FWRITE)

but also
- passing the address of int x = 1
- passing a NULL address
- not passing anything (!)

I'm starting to think that perhaps we should as well just comment the
#define TIOCFLUSH from the headers, since there are so many bogus
callers of the interface.

Samuel