Re: [9fans] accept in dial(2)

[andrey mirtchovski <mirtchov@cpsc.ucalgary.ca>]

> There seems to be some confusion about which file descriptor
> accept should take as its first argument: the one announce
> returned, the one listen returned, or it doesn't matter.
> A quick kernel grep suggests that only port/devsdp.c still
> recognises the word "accept", per the comment
>
> 	write(ctl, buf, n); /* ignore return value, network might not need accepts */
>
> at /sys/src/libc/9sys/announce.c:148.  dial(2) says
> ``Accept accepts a call received by listen'', which
> isn't completely clear, but the example given uses
> the fd returned by listen, which makes sense to me.
> On the other hand, listen, listen1 and tftpd use the
> fd returned by announce.
>
> Does anybody know which fd accept should take, and if it
> matters?


the listen one, i believe.

 here's a snippet from a service not unlike any other fs in p9:

		acfd = announce("tcp!*!18000", adir);
		if(acfd < 0)
			sysfatal("announce: %r");

		for(;;){
			lcfd = listen(adir, ldir);
			if(lcfd < 0)
				sysfatal("listen: %r");

			switch(rfork(RFPROC | RFMEM | RFNOWAIT)){
			case -1:
				fprint(2, "fork listen: %r");
				continue;
			default:
				continue;
			case 0:
				break;
			}
			dfd = accept(lcfd, ldir);
			if(dfd < 0)
				sysfatal("accept: %r");

			s = emalloc9p(sizeof *s);
			*s = fs;
			s->infd = s->outfd = dfd;
			srv(s);
			free(s);
			_exits(nil);
		}

andrey