On 16.09.25 11:33, Daniel P. Berrangé wrote:
On Mon, Sep 15, 2025 at 10:30:58PM +0300, Vladimir Sementsov-Ogievskiy wrote:
Use common qemu_set_blocking() instead.
Note that pre-patch the behavior of Win32 and Linux realizations
are inconsistent: we ignore failure for Win32, and assert success
for Linux.
How do we convert the callers?
1. Most of callers call qemu_socket_set_nonblock() on a
freshly created socket fd, in conditions when we may simply
report an error. Seems correct switching to error handling
both for Windows (pre-patch error is ignored) and Linux
(pre-patch we assert success). Anyway, we normally don't
expect errors in these cases.
Still in tests let's use &error_abort for simplicity.
What are exclusions?
2. hw/virtio/vhost-user.c - we are inside #ifdef CONFIG_LINUX,
so no damage in switching to error handling from assertion.
3. io/channel-socket.c: here we convert both old calls to
qemu_socket_set_nonblock() and qemu_socket_set_block() to
one new call. Pre-patch we assert success for Linux in
qemu_socket_set_nonblock(), and ignore all other errors here.
So, for Windows switch is a bit dangerous: we may get
new errors or crashes(when error_abort is passed) in
cases where we have silently ignored the error before
(was it correct in all such cases, if they were?) Still,
there is no other way to stricter API than take
this risk.
4. util/vhost-user-server - compiled only for Linux (see
util/meson.build), so we are safe, switching from assertion to
&error_abort.
Note: In qga/channel-posix.c we use g_warning(), where g_printerr()
would actually be a better choice. Still let's for now follow
common style of qga, where g_warning() is commonly used to print
such messages, and no call to g_printerr(). Converting everything
to use g_printerr() should better be another series.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
contrib/ivshmem-server/ivshmem-server.c | 9 ++++++++-
hw/hyperv/syndbg.c | 4 +++-
hw/virtio/vhost-user.c | 5 ++++-
include/qemu/sockets.h | 1 -
io/channel-socket.c | 7 +++----
net/dgram.c | 16 +++++++++++++---
net/l2tpv3.c | 5 +++--
net/socket.c | 20 ++++++++++++++++----
qga/channel-posix.c | 7 ++++++-
tests/unit/socket-helpers.c | 4 +++-
tests/unit/test-crypto-tlssession.c | 8 ++++----
util/oslib-posix.c | 7 -------
util/oslib-win32.c | 5 -----
util/vhost-user-server.c | 4 ++--
14 files changed, 65 insertions(+), 37 deletions(-)
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index d805a92394..b3416ab956 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -78,7 +78,7 @@ static void vmsg_unblock_fds(VhostUserMsg *vmsg)
}
for (i = 0; i < vmsg->fd_num; i++) {
- qemu_socket_set_nonblock(vmsg->fds[i]);
+ qemu_set_blocking(vmsg->fds[i], false, &error_abort);
}
}
The caller of this method is able to handle errors more gracefully
than abort.
@@ -303,7 +303,7 @@ set_watch(VuDev *vu_dev, int fd, int vu_evt,
vu_fd_watch->fd = fd;
vu_fd_watch->cb = cb;
- qemu_socket_set_nonblock(fd);
+ qemu_set_blocking(fd, false, &error_abort);
aio_set_fd_handler(server->ctx, fd, kick_handler,
NULL, NULL, NULL, vu_fd_watch);
vu_fd_watch->vu_dev = vu_dev;
Can we put a TODO here that error_abort should be fixed to be more
graceful - either by moving the set_blocking call out of this
callback entirely, or allowing this method to return errors.
will do
--
Best regards,
Vladimir
