Re: telnet segfaults on Hurd

[Alain Magloire]

Bonjour

> Hi,
> 
> telnet segfaults on Hurd because of that:
> 
> TerminalFlushOutput()
> {
> #ifdef  TIOCFLUSH
>     (void) ioctl(fileno(stdout), TIOCFLUSH, (char *) 0);
> #else
>     (void) ioctl(fileno(stdout), TCFLSH, (char *) 0);
> #endif
> }
> 
> TIOCFLUSH expects an (int *) as third argument.  The Hurd always requires
> the arguments, as they are pasted to and from a server RPC.

It seems to me, that the Hurd should do a quick sanity check for
the null argument.

> Can't we better use tcdrain(fileno(stdout)) here anyway?

Not exactly, you probably mean: tcflush () not tcdrain ().
tcflush is more or less equivalent to

int
tcflush (int fd, int arg)
{
        /* Some checking of TCIFLUSH | TCOFLUSH | TCIOFLUSH was left out.  */
        return ioctl (fd, TIOCFLUSH, (void *) &arg);
}

This is the good way but the long way to go, since tcflush()
needs to be check(configure.in) with a proper replacement in ineutils/lib.

Telnet client/server is litter with such code.  And frankly at this time I
lack the courage to clean this out.

A simple fix is

TerminalFlushOutput()
{
  int out = 0;
#ifdef  TIOCFLUSH
    (void) ioctl(fileno(stdout), TIOCFLUSH, (char *) &out);
#else
    (void) ioctl(fileno(stdout), TCFLSH, (char *) &out);
#endif
}

Give it a try.

--
alain