From: Phillip Wood <phillip.wood123@gmail.com>
Date: Mon, 30 Jun 2025 09:00:17 GMT
Subject: Re: [PATCH v3] daemon: correctly handle soft accept() errors in service_loop
Message-ID: <0d507273-8b8c-42d9-a14f-27a5da0dac27@gmail.com>
In-Reply-To: <20250627231404.27100-1-carenas@gmail.com>

Hi Carlo

This looks good

Thanks

Phillip

On 28/06/2025 00:14, Carlo Marcelo Arenas Belón wrote:
> Since df076bdbcc ([PATCH] GIT: Listen on IPv6 as well, if available.,
> 2005-07-23), the original error checking was included in an inner loop
> unchanged, where its effect was different.
> 
> Instead of retrying, after a EINTR during accept() in the listening
> socket, it will advance to the next one and try with that instead,
> leaving the client waiting for another round.
> 
> Make sure to retry with the same listener socket that failed originally.
> 
> To avoid an unlikely busy loop, fallback to the old behaviour after a
> couple of attempts.
> 
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
> ---
>   daemon.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/daemon.c b/daemon.c
> index d1be61fd57..9ac9efa17c 100644
> --- a/daemon.c
> +++ b/daemon.c
> @@ -1153,11 +1153,19 @@ static int service_loop(struct socketlist *socklist)
>   #endif
>   				} ss;
>   				socklen_t sslen = sizeof(ss);
> -				int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
> +				int incoming;
> +				int retry = 3;
> +
> +			redo:
> +				incoming = accept(pfd[i].fd, &ss.sa, &sslen);
>   				if (incoming < 0) {
>   					switch (errno) {
> -					case EAGAIN:
>   					case EINTR:
> +						if (--retry)
> +							goto redo;
> +
> +						/* fallthrough */
> +					case EAGAIN:
>   					case ECONNABORTED:
>   						continue;
>   					default: