From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:41862) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QPJ7s-0000hG-Bs for qemu-devel@nongnu.org; Wed, 25 May 2011 14:48:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QPJ7r-000640-FL for qemu-devel@nongnu.org; Wed, 25 May 2011 14:48:12 -0400 Received: from mtagate2.uk.ibm.com ([194.196.100.162]:46456) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QPJ7r-00063k-8N for qemu-devel@nongnu.org; Wed, 25 May 2011 14:48:11 -0400 Received: from d06nrmr1806.portsmouth.uk.ibm.com (d06nrmr1806.portsmouth.uk.ibm.com [9.149.39.193]) by mtagate2.uk.ibm.com (8.13.1/8.13.1) with ESMTP id p4PImAb3028714 for ; Wed, 25 May 2011 18:48:10 GMT Received: from d06av09.portsmouth.uk.ibm.com (d06av09.portsmouth.uk.ibm.com [9.149.37.250]) by d06nrmr1806.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p4PImAL11957912 for ; Wed, 25 May 2011 19:48:10 +0100 Received: from d06av09.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av09.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p4PIm9L9022800 for ; Wed, 25 May 2011 12:48:09 -0600 From: Stefan Hajnoczi Date: Wed, 25 May 2011 19:48:01 +0100 Message-Id: <1306349281-16913-2-git-send-email-stefanha@linux.vnet.ibm.com> In-Reply-To: <1306349281-16913-1-git-send-email-stefanha@linux.vnet.ibm.com> References: <1306349281-16913-1-git-send-email-stefanha@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 2/2] QMP: add server mode to QEMUMonitorProtocol List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , Luiz Capitulino QEMU supports socket chardevs that establish connections like a server or a client. The QEMUMonitorProtocol class only supports connecting as a client. It is not possible to connect race-free when launching QEMU since trying to connect before QEMU has bound and is listening on the socket results in failure. Add the QEMUMonitorProtocol(server=True) argument to bind and listen on the socket. The QEMU process can then be launched and connects to the already existing QMP socket without a race condition: qmp = qmp.QEMUMonitorProtocol(monitor_path, server=True) popen = subprocess.Popen(args) qmp.accept() Signed-off-by: Stefan Hajnoczi --- QMP/qmp.py | 43 ++++++++++++++++++++++++++++++++----------- 1 files changed, 32 insertions(+), 11 deletions(-) diff --git a/QMP/qmp.py b/QMP/qmp.py index 2565508..c7dbea0 100644 --- a/QMP/qmp.py +++ b/QMP/qmp.py @@ -22,19 +22,24 @@ class QMPCapabilitiesError(QMPError): pass class QEMUMonitorProtocol: - def __init__(self, address): + def __init__(self, address, server=False): """ Create a QEMUMonitorProtocol class. @param address: QEMU address, can be either a unix socket path (string) or a tuple in the form ( address, port ) for a TCP connection - @note No connection is established, this is done by the connect() method + @param server: server mode listens on the socket (bool) + @raise socket.error on socket connection errors + @note No connection is established, this is done by the connect() or + accept() methods """ self.__events = [] self.__address = address self.__sock = self.__get_sock() - self.__sockfile = self.__sock.makefile() + if server: + self.__sock.bind(self.__address) + self.__sock.listen(1) def __get_sock(self): if isinstance(self.__address, tuple): @@ -43,6 +48,17 @@ class QEMUMonitorProtocol: family = socket.AF_UNIX return socket.socket(family, socket.SOCK_STREAM) + def __negotiate_capabilities(self): + self.__sockfile = self.__sock.makefile() + greeting = self.__json_read() + if greeting is None or not greeting.has_key('QMP'): + raise QMPConnectError + # Greeting seems ok, negotiate capabilities + resp = self.cmd('qmp_capabilities') + if "return" in resp: + return greeting + raise QMPCapabilitiesError + def __json_read(self, only_event=False): while True: data = self.__sockfile.readline() @@ -67,14 +83,19 @@ class QEMUMonitorProtocol: @raise QMPCapabilitiesError if fails to negotiate capabilities """ self.__sock.connect(self.__address) - greeting = self.__json_read() - if greeting is None or not greeting.has_key('QMP'): - raise QMPConnectError - # Greeting seems ok, negotiate capabilities - resp = self.cmd('qmp_capabilities') - if "return" in resp: - return greeting - raise QMPCapabilitiesError + return self.__negotiate_capabilities() + + def accept(self): + """ + Await connection from QMP Monitor and perform capabilities negotiation. + + @return QMP greeting dict + @raise socket.error on socket connection errors + @raise QMPConnectError if the greeting is not received + @raise QMPCapabilitiesError if fails to negotiate capabilities + """ + self.__sock, _ = self.__sock.accept() + return self.__negotiate_capabilities() def cmd_obj(self, qmp_cmd): """ -- 1.7.4.4