From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 2874D5A0279 for ; Fri, 11 Aug 2023 07:12:39 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=201602; t=1691730753; bh=mPqMX65hnsm8wFJvLKw1OP3gEES+bFE5l4typ8ZVI64=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=exFhvDrd3M/WouXwp+0YuiKYiZgiTp2HRRpitsp366UbhKVBzPxhtvMpmfl22a0Ve iTGonWf2ezmWZmxgpAdhGrFBNmsyBLL8sCck4sWcgR9DcvHCd66YBC6ah18WxZKw0f Zu/qU8uA5SQVqi/B19NUYGbpXrCAAgTlqMLS2pGc= Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4RMX3j1S6fz4wZJ; Fri, 11 Aug 2023 15:12:33 +1000 (AEST) From: David Gibson To: passt-dev@passt.top, Stefano Brivio Subject: [PATCH v3 02/13] tap: Clean up behaviour for errors on listening Unix socket Date: Fri, 11 Aug 2023 15:12:18 +1000 Message-ID: <20230811051229.343838-3-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230811051229.343838-1-david@gibson.dropbear.id.au> References: <20230811051229.343838-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: TW72NIQMFL4C6HM536MNY64OVGU6VN2E X-Message-ID-Hash: TW72NIQMFL4C6HM536MNY64OVGU6VN2E X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: We call tap_sock_unix_new() to handle a new connection to the qemu socket if we get an EPOLLIN event on c->fd_tap_listen. If we get any other event on the fd, we'll fall through to the "tap reset" path. But that won't do anything relevant to the listening socket, it will just close the already connected socket. Furthermore, the only other event we're subscribed to for the listening socket is EPOLLRDHUP, which doesn't apply to a non connected socket. Remove EPOLLRDHUP from the subscribed events. We don't need to explicitly add EPOLLERR, because errors are always reported. There's no obvious case that would cause an error on a listening socket anyway, and it's not obvious how we'd recover, treat it as a fatal error if it ever does happen. Finally, fold all this handling into the tap_sock_unix_new() function, there's no real reason to split it between there and tap_handler(). Signed-off-by: David Gibson --- tap.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/tap.c b/tap.c index b4967d0..dac6db0 100644 --- a/tap.c +++ b/tap.c @@ -1108,7 +1108,7 @@ static void tap_sock_unix_init(struct ctx *c) listen(fd, 0); ev.data.fd = c->fd_tap_listen = fd; - ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP; + ev.events = EPOLLIN | EPOLLET; epoll_ctl(c->epollfd, EPOLL_CTL_ADD, c->fd_tap_listen, &ev); info("You can now start qemu (>= 7.2, with commit 13c6be96618c):"); @@ -1121,14 +1121,18 @@ static void tap_sock_unix_init(struct ctx *c) /** * tap_sock_unix_new() - Handle new connection on listening socket * @c: Execution context + * @events: epoll events */ -static void tap_sock_unix_new(struct ctx *c) +static void tap_sock_unix_new(struct ctx *c, uint32_t events) { struct epoll_event ev = { 0 }; int v = INT_MAX / 2; struct ucred ucred; socklen_t len; + if (events != EPOLLIN) + die("Error on listening Unix socket, exiting"); + len = sizeof(ucred); /* Another client is already connected: accept and close right away. */ @@ -1284,8 +1288,8 @@ static void tap_sock_reset(struct ctx *c) void tap_handler(struct ctx *c, int fd, uint32_t events, const struct timespec *now) { - if (fd == c->fd_tap_listen && events == EPOLLIN) { - tap_sock_unix_new(c); + if (fd == c->fd_tap_listen) { + tap_sock_unix_new(c, events); return; } -- 2.41.0