[rfc] xioctl()

[Tito]

On Saturday 23 June 2007 22:37:32 you wrote:
> On Saturday 23 June 2007, Tito wrote:
> > On Saturday 23 June 2007 22:11:53 Tito wrote:
> > > On Saturday 23 June 2007 20:10:39 Bernhard Fischer wrote:
> > > > On Sat, Jun 23, 2007 at 01:31:19PM -0400, Mike Frysinger wrote:
> > > > >On Saturday 23 June 2007, Mike Frysinger wrote:
> > > > >> +int xioctl(int fd, int request, unsigned long arg)
> > > > >> +{
> > > > >> +       int ret = ioctl(fd, request, arg);
> > > > >> +       if (ret != 0)
> > > > >> +               bb_perror_msg_and_die("ioctl");
> > > > >> +       return ret;
> > > > >> +}
> > > > >
> > > > >actually now that i think about it, considering the usage here (people
> > > > > usually only care if it fails, they dont want to read the return
> > > > > value), we probably can do:
> > > > >void xioctl(...)
> > > >
> > > > Sounds ok to me. I had a patch which did this but did not apply it (and
> > > > forgot to ask..) since i though that discarding the information about
> > > > which ioctl it was that failed would not be well received, back then.
> > > >
> > > > Let's hear what vda says, i'd say fore! :)
> > > > _______________________________________________
> > > > busybox mailing list
> > > > busybox at busybox.net
> > > > http://busybox.net/cgi-bin/mailman/listinfo/busybox
> > >
> > > Hi,
> > > in hdparm.c we already have:
> > >
> > > /* Busybox messages and functions */
> > > static int bb_ioctl(int fd, int request, void *argp, const char *string)
> > > {
> > > 	int e = ioctl(fd, request, argp);
> > > 	if (e && string)
> > > 		bb_perror_msg(" %s", string);
> > > 	return e;
> > > }
> > >
> > > so that we can pass also an error message if needed, maybe this could be
> > > also
> > >
> > > static int bb_ioctl(int fd, int request, void *argp, ...)
> > > {
> > > 	va_list p;
> > > 	char *string;
> > > 	va_start(p, request);
> > > 	string = va_arg(va_list p,  (char *));
> > >
> > > 	int e = ioctl(fd, request, argp);
> > > 	if (e && string)
> > > 		bb_perror_msg(" %s", string);
> > > 	va_end(p);
> > > 	return e;
> > > }
> > >
> > > untested, just an idea.
> > >
> > > Ciao,
> > > Tito
> >
> > or better:
> >
> > static void xioctl(int fd, int request, void *argp, ...)
> >  {
> >  	va_list p;
> >  	char *string;
> >  	va_start(p, argp);
> >  	string = va_arg(va_list p,  (char *));
> >
> >  	int e = ioctl(fd, request, argp);
> >  	if (e)
> >  		bb_perror_msg_and_die(" %s", (string) ? string : "ioctl");
> >  	va_end(p);
> >   }
> 
> i saw the hdparm code, but that's the only case i saw where the fail was 
> conditional, so i'm not sure hdparm is worth folding in
> -mike
> 

My suggestion was more about allowing to pass an optional error message string.

Ciao,
Tito