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(unknown [2a02:6bf:8080:16c::1:b]) by mail-nwsmtp-smtp-corp-main-69.vla.yp-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id 5EQRob1Gj0U0-IfX8UzlS; Tue, 16 Sep 2025 16:14:14 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1758028454; bh=zrq9XhA2TuK4K/azMAe1NuiXl/HbWLCQkj9cUHTX4o8=; h=Cc:Message-ID:References:Date:In-Reply-To:Subject:To:From; b=EpzJLdhFsLrB15vYd4N6ivKeVDU1Rb5EAPcCDquW7n0eo7rYK5bKyAQg6MZSVIKA7 hDdYHe53k3FMHzZgXapZhTk6Czn2+Pgya9EYIkKpy+1/bbZMsbOAXyiK7IEYgwMChp TlV72czuqd++yhJgj2gP4+1ctr2xQ17xO3RoH33g= Authentication-Results: mail-nwsmtp-smtp-corp-main-69.vla.yp-c.yandex.net; dkim=pass header.i=@yandex-team.ru From: Vladimir Sementsov-Ogievskiy To: berrange@redhat.com Cc: qemu-devel@nongnu.org, peterx@redhat.com, qemu-block@nongnu.org, vsementsov@yandex-team.ru, leiyang@redhat.com, marcandre.lureau@redhat.com Subject: [PATCH v5 08/13] io/channel-socket: rework qio_channel_socket_copy_fds() Date: Tue, 16 Sep 2025 16:13:57 +0300 Message-ID: <20250916131403.368343-9-vsementsov@yandex-team.ru> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250916131403.368343-1-vsementsov@yandex-team.ru> References: <20250916131403.368343-1-vsementsov@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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:c0e:500:1:45:d181:df01; envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1a.mail.yandex.net X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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, RCVD_IN_DNSWL_LOW=-0.7, 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: 1758028685769116600 We want to switch from qemu_socket_set_block() to newer qemu_set_blocking(), which provides return status of operation, to handle errors. Still, we want to keep qio_channel_socket_readv() interface clean, as currently it allocate @fds only on success. So, in case of error, we should close all incoming fds and keep user's @fds untouched or zero. Let's make separate functions qio_channel_handle_fds() and qio_channel_cleanup_fds(), to achieve what we want. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Daniel P. Berrang=C3=A9 --- include/io/channel.h | 8 +++--- io/channel-socket.c | 67 +++++++++++++++++++++++++++++++++----------- 2 files changed, 55 insertions(+), 20 deletions(-) diff --git a/include/io/channel.h b/include/io/channel.h index 999a8f5f23..0f25ae0069 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -124,8 +124,8 @@ struct QIOChannelClass { * 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. + * @fds and @nfds are set only on success path. Still, setting + * @fds and @nfds to zero is acceptable on failure path. */ ssize_t (*io_readv)(QIOChannel *ioc, const struct iovec *iov, @@ -246,8 +246,8 @@ void qio_channel_set_name(QIOChannel *ioc, * 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. + * _only_ on success path. Still, @fds and @nfds + * may be set to zero on failure path. * qio_channel_readv_full() guarantees that all * incoming fds are set BLOCKING (unless * QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING flag diff --git a/io/channel-socket.c b/io/channel-socket.c index f7e3cb9742..e53d9ac76f 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -464,8 +464,7 @@ static void qio_channel_socket_finalize(Object *obj) =20 #ifndef WIN32 static void qio_channel_socket_copy_fds(struct msghdr *msg, - int **fds, size_t *nfds, - bool preserve_blocking) + int **fds, size_t *nfds) { struct cmsghdr *cmsg; =20 @@ -473,7 +472,7 @@ static void qio_channel_socket_copy_fds(struct msghdr *= msg, *fds =3D NULL; =20 for (cmsg =3D CMSG_FIRSTHDR(msg); cmsg; cmsg =3D CMSG_NXTHDR(msg, cmsg= )) { - int fd_size, i; + int fd_size; int gotfds; =20 if (cmsg->cmsg_len < CMSG_LEN(sizeof(int)) || @@ -491,24 +490,53 @@ static void qio_channel_socket_copy_fds(struct msghdr= *msg, gotfds =3D fd_size / sizeof(int); *fds =3D g_renew(int, *fds, *nfds + gotfds); memcpy(*fds + *nfds, CMSG_DATA(cmsg), fd_size); + *nfds +=3D gotfds; + } +} =20 - for (i =3D 0; i < gotfds; i++) { - int fd =3D (*fds)[*nfds + i]; - if (fd < 0) { - continue; - } +static bool qio_channel_handle_fds(int *fds, size_t nfds, + bool preserve_blocking, Error **errp) +{ + int *end =3D fds + nfds, *fd; + +#ifdef MSG_CMSG_CLOEXEC + if (preserve_blocking) { + /* Nothing to do */ + return true; + } +#endif =20 - if (!preserve_blocking) { - /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ - qemu_socket_set_block(fd); + for (fd =3D fds; fd !=3D end; fd++) { + if (*fd < 0) { + continue; + } + + if (!preserve_blocking) { + /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ + if (!qemu_set_blocking(*fd, true, errp)) { + return false; } + } =20 #ifndef MSG_CMSG_CLOEXEC - qemu_set_cloexec(fd); + qemu_set_cloexec(*fd); #endif + } + + return true; +} + +static void qio_channel_cleanup_fds(int **fds, size_t *nfds) +{ + for (size_t i =3D 0; i < *nfds; i++) { + if ((*fds)[i] < 0) { + continue; } - *nfds +=3D gotfds; + close((*fds)[i]); } + + g_clear_pointer(fds, g_free); + *nfds =3D 0; } =20 =20 @@ -559,9 +587,16 @@ static ssize_t qio_channel_socket_readv(QIOChannel *io= c, } =20 if (fds && nfds) { - qio_channel_socket_copy_fds( - &msg, fds, nfds, - flags & QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING); + bool preserve_blocking =3D + flags & QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING; + + qio_channel_socket_copy_fds(&msg, fds, nfds); + + if (!qio_channel_handle_fds(*fds, *nfds, + preserve_blocking, errp)) { + qio_channel_cleanup_fds(fds, nfds); + return -1; + } } =20 return ret; --=20 2.48.1