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Re: [Qemu-devel] [PATCH v8 06/13] qemu.py: make sure we only remove file
From: |
Amador Pahim |
Subject: |
Re: [Qemu-devel] [PATCH v8 06/13] qemu.py: make sure we only remove files we create |
Date: |
Thu, 14 Sep 2017 21:38:13 +0200 |
On Tue, Sep 5, 2017 at 5:18 AM, Fam Zheng <address@hidden> 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 <address@hidden>
>> ---
>> 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.
>
>> + 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.
>
>> + 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
- Re: [Qemu-devel] [PATCH v8 02/13] qemu.py: avoid writing to stdout/stderr, (continued)
[Qemu-devel] [PATCH v8 05/13] qemu.py: include debug information on launch error, Amador Pahim, 2017/09/01
[Qemu-devel] [PATCH v8 07/13] qemu.py: close _qemu_log_path on cleanup, Amador Pahim, 2017/09/01
[Qemu-devel] [PATCH v8 09/13] qemu.py: always cleanup on shutdown(), Amador Pahim, 2017/09/01