For ease of review, this patch adds an AioContext pointer to the
QIONetListener struct, the code to trace it, and refactors
listener->io_source to instead be an array of utility structs; but the
aio_context pointer is always NULL until the next patch adds an API to
set it. There should be no semantic change in this patch.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20251113011625.878876-25-eblake@redhat.com>
io/net-listener.c has two modes of use: asynchronous (the user calls
qio_net_listener_set_client_func to wake up the callback via the
global GMainContext, or qio_net_listener_set_client_func_full to wake
up the callback via the caller's own alternative GMainContext), and
synchronous (the user calls qio_net_listener_wait_client which creates
its own GMainContext and waits for the first client connection before
returning, with no need for a user's callback). But commit 938c8b79
has a latent logic flaw: when qio_net_listener_wait_client finishes on
its temporary context, it reverts all of the siocs back to the global
GMainContext rather than the potentially non-NULL context they might
have been originally registered with. Similarly, if the user creates
a net-listener, adds initial addresses, registers an async callback
with a non-default context (which ties to all siocs for the initial
addresses), then adds more addresses with qio_net_listener_add, the
siocs for later addresses are blindly placed in the global context,
rather than sharing the context of the earlier ones.
In practice, I don't think this has caused issues. As pointed out by
the original commit, all async callers prior to that commit were
already okay with the NULL default context; and the typical usage
pattern is to first add ALL the addresses the listener will pay
attention to before ever setting the async callback. Likewise, if a
file uses only qio_net_listener_set_client_func instead of
qio_net_listener_set_client_func_full, then it is never using a custom
context, so later assignments of async callbacks will still be to the
same global context as earlier ones. Meanwhile, any callers that want
to do the sync operation to grab the first client are unlikely to
register an async callback; altogether bypassing the question of
whether later assignments of a GSource are being tied to a different
context over time.
I do note that chardev/char-socket.c is the only file that calls both
qio_net_listener_wait_client (sync for a single client in
tcp_chr_accept_server_sync), and qio_net_listener_set_client_func_full
(several places, all with chr->gcontext, but sometimes with a NULL
callback function during teardown). But as far as I can tell, the two
uses are mutually exclusive, based on the is_waitconnect parameter to
qmp_chardev_open_socket_server.
That said, it is more robust to remember when an async callback
function is tied to a non-default context, and have both the sync wait
and any late address additions honor that same context. That way, the
code will be robust even if a later user performs a sync wait for a
specific client in the middle of servicing a longer-lived
QIONetListener that has an async callback for all other clients.
CC: qemu-stable@nongnu.org
Fixes: 938c8b79 ("qio: store gsources for net listeners", v2.12.0)
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20251113011625.878876-19-eblake@redhat.com>
Upcoming patches will adjust how net_listener watches for new client
connections; adding trace points now makes it easier to debug that the
changes work as intended. For example, adding
--trace='qio_net_listener*' to the qemu-storage-daemon command line
before --nbd-server will track when the server first starts listening
for clients.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20251113011625.878876-17-eblake@redhat.com>
Add a task dispatcher for gnutls_bye similar to the
qio_channel_tls_handshake_task(). The gnutls_bye() call might be
interrupted and so it needs to be rescheduled.
The migration code will make use of this to help the migration
destination identify a premature EOF. Once the session termination is
in place, any EOF that happens before the source issued gnutls_bye()
will be considered an error.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
This is for code which needs a portable equivalent to a QIOChannelFile
connected to /dev/null.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Commit e50caf4a5c ("tracing: convert documentation to rST")
converted docs/devel/tracing.txt to docs/devel/tracing.rst.
We still have several references to the old file, so let's fix them
with the following command:
sed -i s/tracing.txt/tracing.rst/ $(git grep -l docs/devel/tracing.txt)
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210517151702.109066-2-sgarzare@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
We spell out sub/dir/ in sub/dir/trace-events' comments pointing to
source files. That's because when trace-events got split up, the
comments were moved verbatim.
Delete the sub/dir/ part from these comments. Gets rid of several
misspellings.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190314180929.27722-3-armbru@redhat.com
Message-Id: <20190314180929.27722-3-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Add the ability for a caller to wait for completion of the
background thread to synchronously dispatch its result, without
needing to wait for the main loop to run the idle callback.
This method needs very careful usage to avoid a dangerous
race condition with the free'ing of the task. The completion
callback is normally invoked from an idle callback registered
with the main loop context. The qio_task_wait_thread method
must only be called if the completion callback has not yet
run. The only safe way to achieve this is to run the
qio_task_wait_thread method from the thread that executes
the main loop.
It is generally a bad idea to use this method since it will
block execution of the main loop, however, the design of
the character devices and its usage from vhostuser already
requires blocking execution.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190211182442.8542-3-berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
It is useful to trace websockets frame encoding/decoding when debugging
problems.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When the websocket handshake fails it is useful to log the real
error message via the trace points for debugging purposes.
Fixes bug: #1715186
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
With the move of some docs/ to docs/devel/ on ac06724a71,
no references were updated.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Currently the QIOTaskFunc signature takes an Object * for
the source, and an Error * for any error. We also need to
be able to provide a result pointer. Rather than continue
to add parameters to QIOTaskFunc, remove the existing
ones and simply pass the QIOTask object instead. This
has methods to access all the other data items required
in the callback impl.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The trace points for util/buffer.c were mistakenly put
in the io/trace-events file, instead of util/trace-events
in
commit 892bd32ea3
Author: Daniel P. Berrange <berrange@redhat.com>
Date: Thu Jun 16 09:39:50 2016 +0100
trace: split out trace events for io/ directory
Move all trace-events for files in the io/ directory to
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1473872624-23285-2-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Move all trace-events for files in the io/ directory to
their own file.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1466066426-16657-5-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
