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(unknown [2a02:6bf:8080:b48::1:39]) by mail-nwsmtp-smtp-corp-main-66.iva.yp-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id EVQIl30GrmI0-ybEIGVHr; Wed, 10 Sep 2025 22:31:16 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1757532676; bh=uMyWlZz8GUek1kf53f51SjKsa9pyhTAqLEXmUSrq4J8=; h=Message-ID:Date:In-Reply-To:Cc:Subject:References:To:From; b=ZF8PiWXYAhyW+imxRDVncIIdw92aYEiIp6D8KIwj7Gs3IPQ1sR9jAhMlZWoYTr5w0 kjk3mVzqKcNjqT593oEiS5ZCnhNClqbElQI30KzYO+Z99QijxiCxWdZLLimrZkI+RF mUhTK0/oWWgvGAHakUPpt4LYh1rYMRFFquXn54os= Authentication-Results: mail-nwsmtp-smtp-corp-main-66.iva.yp-c.yandex.net; dkim=pass header.i=@yandex-team.ru From: Vladimir Sementsov-Ogievskiy To: berrange@redhat.com Cc: peterx@redhat.com, farosas@suse.de, steven.sistare@oracle.com, vsementsov@yandex-team.ru, qemu-devel@nongnu.org Subject: [PATCH v4 2/2] io/channel: document how qio_channel_readv_full() handles fds Date: Wed, 10 Sep 2025 22:31:12 +0300 Message-ID: <20250910193112.1220763-3-vsementsov@yandex-team.ru> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250910193112.1220763-1-vsementsov@yandex-team.ru> References: <20250910193112.1220763-1-vsementsov@yandex-team.ru> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a02:6b8:c41:1300:1:45:d181:df01; envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1d.mail.yandex.net X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @yandex-team.ru) X-ZM-MESSAGEID: 1757532736330116600 Content-Type: text/plain; charset="utf-8" The only realization, which may have incoming fds is qio_channel_socket_readv() (in io/channel-socket.c). qio_channel_socket_readv() do call (through qio_channel_socket_copy_fds()) qemu_socket_set_block() and qemu_set_cloexec() for each fd. Also, qio_channel_socket_copy_fds() is called at the end of qio_channel_socket_readv(), on success path. Signed-off-by: Vladimir Sementsov-Ogievskiy Acked-by: Peter Xu Reviewed-by: Daniel P. Berrang=C3=A9 --- include/io/channel.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/io/channel.h b/include/io/channel.h index 12266256a8..c7f64506f7 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -118,6 +118,15 @@ struct QIOChannelClass { size_t nfds, int flags, Error **errp); + + /* + * The io_readv handler must guarantee that all + * incoming fds are set BLOCKING (unless + * QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING flag is set) and + * CLOEXEC (if available). + * @fds and @nfds are set only on success path, and untouched + * in case of errors. + */ ssize_t (*io_readv)(QIOChannel *ioc, const struct iovec *iov, size_t niov, @@ -125,6 +134,7 @@ struct QIOChannelClass { size_t *nfds, int flags, Error **errp); + int (*io_close)(QIOChannel *ioc, Error **errp); GSource * (*io_create_watch)(QIOChannel *ioc, @@ -235,6 +245,13 @@ void qio_channel_set_name(QIOChannel *ioc, * was allocated. It is the callers responsibility * to call close() on each file descriptor and to * call g_free() on the array pointer in @fds. + * @fds allocated and set (and @nfds is set too) + * _only_ on success path. These parameters are + * untouched in case of errors. + * qio_channel_readv_full() guarantees that all + * incoming fds are set BLOCKING (unless + * QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING flag + * is set) and CLOEXEC (if available). * * It is an error to pass a non-NULL @fds parameter * unless qio_channel_has_feature() returns a true --=20 2.48.1