Re: [PATCH bpf v3 2/4] selftest/bpf: Support SOCK_STREAM in unix_inet_redir_to_connected()

On 7/22/24 21:26, Jakub Sitnicki wrote:

On Mon, Jul 22, 2024 at 03:07 PM +02, Michal Luczaj wrote:

quoted

quoted

Classic cleanup with goto to close sockets is all right, but if you're
feeling brave and aim for something less branchy, I've noticed we have
finally started using __attribute__((cleanup)):

https://elixir.bootlin.com/linux/v6.10/source/tools/testing/selftests/bpf/progs/iters.c#L115

I've tried. Is such "ownership passing" (to inhibit the cleanup) via
construct like take_fd()[1] welcomed?

I'm fine with having such a helper to complement the cleanup attribute.
Alternatively, we can always open code it like it used to be in systemd
at first [1], if other reviewers don't warm up to it :-)

[1] https://github.com/systemd/systemd/blob/main/coccinelle/take-fd.cocci

OK, so I've kept create_pair()'s __cleanupfication as the last part of the
series:
https://lore.kernel.org/netdev/20240724-sockmap-selftest-fixes-v1-0-46165d224712@rbox.co (local)

quoted

[1] https://lore.kernel.org/all/20240627-work-pidfs-v1-1-7e9ab6cc3bb1@kernel.org/ (local)

static inline void close_fd(int *fd)
{
	if (*fd >= 0)
		xclose(*fd);
}

#define __closefd __attribute__((cleanup(close_fd)))

static inline int create_pair(int family, int sotype, int *c, int *p)
{
	struct sockaddr_storage addr;
	socklen_t len = sizeof(addr);
	int err;

	int s __closefd = socket_loopback(family, sotype);
	if (s < 0)
		return s;

	err = xgetsockname(s, sockaddr(&addr), &len);
	if (err)
		return err;

	int s0 __closefd = xsocket(family, sotype, 0);

I'd stick to no declarations in the body. Init to -1 or -EBADF.

All right, it just felt wrong to (demand to) initialize variables with some
magic values. __attribute__((setup(set_negative))) would solve that :) I've
toyed with `DEFINE_CLASS(fd, int, if (_T >= 0) xclose(_T), -EBADF, void)`
but it felt wrong, too.

quoted

	case SOCK_STREAM:
	case SOCK_SEQPACKET:
		*p = xaccept_nonblock(s, NULL, NULL);

I wouldn't touch output arguments until we have succedeed.  Another
local var will be handy.

OK, sure. Thanks.