From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38422) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dsa5e-000468-Is for qemu-devel@nongnu.org; Thu, 14 Sep 2017 15:46:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dsa5Z-0001MG-GU for qemu-devel@nongnu.org; Thu, 14 Sep 2017 15:46:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34392) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dsa5Z-0001KA-7N for qemu-devel@nongnu.org; Thu, 14 Sep 2017 15:46:17 -0400 Date: Thu, 14 Sep 2017 16:46:10 -0300 From: Eduardo Habkost Message-ID: <20170914194610.GB23492@localhost.localdomain> References: <20170901112829.2571-1-apahim@redhat.com> <20170901112829.2571-7-apahim@redhat.com> <20170905031853.GN22515@lemon.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH v8 06/13] qemu.py: make sure we only remove files we create List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Amador Pahim Cc: Fam Zheng , qemu-devel@nongnu.org, Stefan Hajnoczi , Daniel Berrange , Max Reitz , Kevin Wolf , Markus Armbruster , Cleber Rosa , =?utf-8?B?THVrw6HFoQ==?= Doktor On Thu, Sep 14, 2017 at 09:38:13PM +0200, Amador Pahim wrote: > On Tue, Sep 5, 2017 at 5:18 AM, Fam Zheng wrote: > > On Fri, 09/01 13:28, Amador Pahim wrote: > >> To launch a VM, we need to create basically two files: the monitor > >> socket (if it's a UNIX socket) and the qemu log file. > >> > >> For the qemu log file, we currently just open the path, which will > >> create the file if it does not exist or overwrite the file if it does > >> exist. > >> > >> For the monitor socket, if it already exists, we are currently removing > >> it, even if it's not created by us. > >> > >> This patch moves to pre_launch() the responsibility to make sure we only > >> create files that are not pre-existent and to populate a list of > >> controlled files. This list will then be used as the reference of > >> files to remove during the cleanup (post_shutdown()). > >> > >> Signed-off-by: Amador Pahim > >> --- > >> scripts/qemu.py | 30 +++++++++++++++++++++++------- > >> 1 file changed, 23 insertions(+), 7 deletions(-) > >> > >> diff --git a/scripts/qemu.py b/scripts/qemu.py > >> index 3ebe5ee0a4..c26e1412f9 100644 > >> --- a/scripts/qemu.py > >> +++ b/scripts/qemu.py > >> @@ -41,6 +41,7 @@ class QEMUMachine(object): > >> monitor_address = os.path.join(test_dir, name + "-monitor.sock") > >> self._monitor_address = monitor_address > >> self._qemu_log_path = os.path.join(test_dir, name + ".log") > >> + self._qemu_log_fd = None > >> self._popen = None > >> self._binary = binary > >> self._args = list(args) # Force copy args in case we modify them > >> @@ -50,6 +51,7 @@ class QEMUMachine(object): > >> self._socket_scm_helper = socket_scm_helper > >> self._debug = debug > >> self._qemu_full_args = None > >> + self._created_files = [] > >> > >> # This can be used to add an unused monitor instance. > >> def add_monitor_telnet(self, ip, port): > >> @@ -128,30 +130,44 @@ class QEMUMachine(object): > >> '-display', 'none', '-vga', 'none'] > >> > >> def _pre_launch(self): > >> - self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address, server=True, > >> - debug=self._debug) > >> + try: > >> + self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address, > >> + server=True, > >> + debug=self._debug) > >> + except: > >> + raise > > > > What's the point of "except: raise"? It seems useless. > > The point is to execute the block in the else only when no exception > happens. When some exception happens, I want to raise it without > executing the else block. Isn't this exactly what Python does when an exception is raised with no "try" block? > > > > >> + else: > >> + if not isinstance(self._monitor_address, tuple): > >> + self._created_files.append(self._monitor_address) > >> + > >> + try: > >> + flags = os.O_CREAT | os.O_EXCL | os.O_WRONLY > >> + os.open(self._qemu_log_path, flags) > > > > Why change to os.open() instead of open()? > > I want to create the file only if it does not exist. The open() flag > 'x' is available only in python 3.3. For python <3.3, we need the > os.open() to have that feature. I'm not sure this extra complexity is really necessary. We could fix all that by using mkdtemp() and deleting the temporary directory on shutdown. > > > > >> + except: > >> + raise > >> + else: > >> + self._created_files.append(self._qemu_log_path) > >> + self._qemu_log_fd = open(self._qemu_log_path, 'wb') > >> > >> def _post_launch(self): > >> self._qmp.accept() > >> > >> def _post_shutdown(self): > >> - if not isinstance(self._monitor_address, tuple): > >> - self._remove_if_exists(self._monitor_address) > >> - self._remove_if_exists(self._qemu_log_path) > >> + while self._created_files: > >> + self._remove_if_exists(self._created_files.pop()) > >> > >> def launch(self): > >> '''Launch the VM and establish a QMP connection''' > >> self._iolog = None > >> self._qemu_full_args = None > >> devnull = open(os.path.devnull, 'rb') > >> - qemulog = open(self._qemu_log_path, 'wb') > >> try: > >> self._pre_launch() > >> self._qemu_full_args = (self._wrapper + [self._binary] + > >> self._base_args() + self._args) > >> self._popen = subprocess.Popen(self._qemu_full_args, > >> stdin=devnull, > >> - stdout=qemulog, > >> + stdout=self._qemu_log_fd, > >> stderr=subprocess.STDOUT, > >> shell=False) > >> self._post_launch() > >> -- > >> 2.13.5 > >> > > > > Fam -- Eduardo