Re: [PATCH v8 10/19] pesto, conf: Have pesto connect to passt and check versions

On Wed, May 06, 2026 at 01:47:10AM +0200, Stefano Brivio wrote:

From: David Gibson

Start implementing pesto in earnest. Create a control/configuration socket in passt. Have pesto connect to it and retrieve a server greeting Perform some basic version checking.

Signed-off-by: David Gibson [sbrivio: Avoid potential recursive calling between conf_accept() and conf_close(), reported by clang-tidy]

Huh. For some reason that warning didn't trip for me. Although it's technically true they can mutually recurse, I believe they're both tail calls, so it shouldn't eat the stack.

[sbrivio: In conf(), check we're not exceeding sizeof(c->control_path) instead of sizeof(c->socket_path), and, in pesto's main(), print argv[optind] instead of argv[1] to indicate an invalid socket path, both reported by Jon Maloy] [sbrivio: In pesto's main(), drop unnecessary newline from error message, reported by Laurent] [sbrivio: Don't use SOCK_NONBLOCK on accept4(), as that only applies to the *new* file descriptor, which we don't want -- set O_NONBLOCK on the listening file descriptor using fcntl()]

Making the new (accepted) socket non-blocking was the intended behaviour here. We also want non-blocking for the listening socket, but that was already done in feab892c7 ("tap, repair: Use SOCK_NONBLOCK and SOCK_CLOEXEC on Unix sockets"). WIth the current design, I guess we don't want non-blocking on the accepted socket, although I don't think it actually matters very much. We will want non-blocking it when we change this to read out the updated rules incrementally, rather than all at once. [snip]

@@ -1072,6 +1080,19 @@ static void conf_open_files(struct ctx *c) if (c->pidfile_fd < 0) die_perror("Couldn't open PID file %s", c->pidfile); } + + c->fd_control = -1; + if (*c->control_path) { + c->fd_control_listen = sock_unix(c->control_path); + if (c->fd_control_listen < 0) { + die_perror("Couldn't open control socket %s", + c->control_path); + } + if (fcntl(c->fd_control_listen, F_SETFL, O_NONBLOCK)) + die_perror("Couldn't set O_NONBLOCK on control socket");

So, this is unneccessary because of feab892c7. -- 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