From 1d4796cd008373a1c1657473f7c7e82eaf32ea1b Mon Sep 17 00:00:00 2001 From: John Snow Date: Thu, 28 Sep 2023 00:49:41 -0400 Subject: [PATCH] python/machine: use socketpair() for console connections MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Create a socketpair for the console output. This should help eliminate race conditions around console text early in the boot process that might otherwise have been dropped on the floor before being able to connect to QEMU under "server,nowait". Signed-off-by: John Snow Reviewed-by: Ani Sinha Reviewed-by: Daniel P. Berrangé Message-id: 20230928044943.849073-5-jsnow@redhat.com Signed-off-by: John Snow --- python/qemu/machine/machine.py | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py index e26109e6f0..4156b8cf7d 100644 --- a/python/qemu/machine/machine.py +++ b/python/qemu/machine/machine.py @@ -159,6 +159,8 @@ class QEMUMachine: self._name = name or f"{id(self):x}" self._sock_pair: Optional[Tuple[socket.socket, socket.socket]] = None + self._cons_sock_pair: Optional[ + Tuple[socket.socket, socket.socket]] = None self._temp_dir: Optional[str] = None self._base_temp_dir = base_temp_dir self._sock_dir = sock_dir @@ -316,8 +318,9 @@ class QEMUMachine: for _ in range(self._console_index): args.extend(['-serial', 'null']) if self._console_set: - chardev = ('socket,id=console,path=%s,server=on,wait=off' % - self._console_address) + assert self._cons_sock_pair is not None + fd = self._cons_sock_pair[0].fileno() + chardev = f"socket,id=console,fd={fd}" args.extend(['-chardev', chardev]) if self._console_device_type is None: args.extend(['-serial', 'chardev:console']) @@ -352,6 +355,10 @@ class QEMUMachine: nickname=self._name ) + if self._console_set: + self._cons_sock_pair = socket.socketpair() + os.set_inheritable(self._cons_sock_pair[0].fileno(), True) + # NOTE: Make sure any opened resources are *definitely* freed in # _post_shutdown()! # pylint: disable=consider-using-with @@ -369,6 +376,9 @@ class QEMUMachine: def _post_launch(self) -> None: if self._sock_pair: self._sock_pair[0].close() + if self._cons_sock_pair: + self._cons_sock_pair[0].close() + if self._qmp_connection: if self._sock_pair: self._qmp.connect() @@ -524,6 +534,11 @@ class QEMUMachine: self._console_socket.close() self._console_socket = None + if self._cons_sock_pair: + self._cons_sock_pair[0].close() + self._cons_sock_pair[1].close() + self._cons_sock_pair = None + def _hard_shutdown(self) -> None: """ Perform early cleanup, kill the VM, and wait for it to terminate. @@ -885,10 +900,19 @@ class QEMUMachine: """ if self._console_socket is None: LOG.debug("Opening console socket") + if not self._console_set: + raise QEMUMachineError( + "Attempt to access console socket with no connection") + assert self._cons_sock_pair is not None + # os.dup() is used here for sock_fd because otherwise we'd + # have two rich python socket objects that would each try to + # close the same underlying fd when either one gets garbage + # collected. self._console_socket = console_socket.ConsoleSocket( - self._console_address, + sock_fd=os.dup(self._cons_sock_pair[1].fileno()), file=self._console_log_path, drain=self._drain_console) + self._cons_sock_pair[1].close() return self._console_socket @property