Re: [PATCH 3/3] tcp, udp: Make {tcp,udp}_listen() return socket fds

[David Gibson <david@gibson.dropbear.id.au>]

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On Sun, Jan 11, 2026 at 12:33:39AM +0100, Stefano Brivio wrote:
> On Mon,  5 Jan 2026 19:28:50 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > {tcp,udp}_listen() currently return 0 on success, rather than the socket
> > fd they created.  Historically, that was because these functions could
> > sometimes create multiple sockets.  We've now refactored things to avoid
> > that, so it makes more sense for them to return the socket on success.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  conf.c | 14 +++++++-------
> >  tcp.c  |  7 ++-----
> >  udp.c  |  4 ++--
> >  3 files changed, 11 insertions(+), 14 deletions(-)
> > 
> > diff --git a/conf.c b/conf.c
> > index cc3c20a9..5db49653 100644
> > --- a/conf.c
> > +++ b/conf.c
> > @@ -149,7 +149,7 @@ static void conf_ports_range_except(const struct ctx *c, char optname,
> >  {
> >  	bool bound_one = false;
> >  	unsigned i;
> > -	int ret;
> > +	int fd;
> >  
> >  	if (first == 0) {
> >  		die("Can't forward port 0 for option '-%c %s'",
> > @@ -185,23 +185,23 @@ static void conf_ports_range_except(const struct ctx *c, char optname,
> >  		fwd->delta[i] = to - first;
> >  
> >  		if (optname == 't')
> > -			ret = tcp_listen(c, PIF_HOST, addr, ifname, i);
> > +			fd = tcp_listen(c, PIF_HOST, addr, ifname, i);
> >  		else if (optname == 'u')
> > -			ret = udp_listen(c, PIF_HOST, addr, ifname, i);
> > +			fd = udp_listen(c, PIF_HOST, addr, ifname, i);
> >  		else
> >  			/* No way to check in advance for -T and -U */
> > -			ret = 0;
> > +			fd = 0;
> >  
> > -		if (ret == -ENFILE || ret == -EMFILE) {
> > +		if (fd == -ENFILE || fd == -EMFILE) {
> >  			die("Can't open enough sockets for port specifier: %s",
> >  			    optarg);
> >  		}
> >  
> > -		if (!ret) {
> > +		if (fd >= 0) {
> >  			bound_one = true;
> >  		} else if (!weak) {
> >  			die("Failed to bind port %u (%s) for option '-%c %s'",
> > -			    i, strerror_(-ret), optname, optarg);
> > +			    i, strerror_(-fd), optname, optarg);
> >  		}
> >  	}
> >  
> > diff --git a/tcp.c b/tcp.c
> > index 67007c05..80b47f3c 100644
> > --- a/tcp.c
> > +++ b/tcp.c
> > @@ -2680,7 +2680,7 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
> >   * @ifname:	Name of interface to bind to, NULL for any
> >   * @port:	Port, host order
> >   *
> > - * Return: 0 on success, negative error code on failure
> > + * Return: Socket fd on success, negative error code on failure
> 
> Nit, here and on udp_listen(): "socket". See also 9e0423e13541 ("style:
> Fix 'Return' comment style").

Oops, fixed.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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