Re: [Qemu-devel] [PATCH v11 2/8] qemu.py: better control of created files

[Eduardo Habkost]

Hi Amador,

First of all, sorry for reviewing this so late.

On Tue, Nov 14, 2017 at 11:22:40AM +0100, 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 create a
> temporary directory to host the files so we can remove the whole
> directory on _post_shutdown().
> 
> Signed-off-by: Amador Pahim <address@hidden>
> ---
>  scripts/qemu.py | 32 ++++++++++++++++++++++++--------
>  1 file changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index 65d9ad688c..d5b1cde044 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -17,6 +17,8 @@ import logging
>  import os
>  import subprocess
>  import qmp.qmp
> +import shutil
> +import tempfile
>  
>  
>  LOG = logging.getLogger(__name__)
> @@ -72,10 +74,10 @@ class QEMUMachine(object):
>              wrapper = []
>          if name is None:
>              name = "qemu-%d" % os.getpid()
> -        if monitor_address is None:
> -            monitor_address = os.path.join(test_dir, name + "-monitor.sock")
> +        self._name = name
>          self._monitor_address = monitor_address
> -        self._qemu_log_path = os.path.join(test_dir, name + ".log")
> +        self._qemu_log_path = None
> +        self._qemu_log_file = None
>          self._popen = None
>          self._binary = binary
>          self._args = list(args)     # Force copy args in case we modify them
> @@ -85,6 +87,8 @@ class QEMUMachine(object):
>          self._socket_scm_helper = socket_scm_helper
>          self._qmp = None
>          self._qemu_full_args = None
> +        self._test_dir = test_dir
> +        self._temp_dir = None
>  
>          # just in case logging wasn't configured by the main script:
>          logging.basicConfig()
> @@ -173,6 +177,13 @@ class QEMUMachine(object):
>                  '-display', 'none', '-vga', 'none']
>  
>      def _pre_launch(self):
> +        self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
> +        if not isinstance(self._monitor_address, tuple):
> +            self._monitor_address = os.path.join(self._temp_dir,
> +                                                 self._name + 
> "-monitor.sock")

Won't this break QEMUMachine(..., monitor_addres='/some/unix/path')?

What about checking if self._monitor_address is None instead?

The rest looks good to me.

> +        self._qemu_log_path = os.path.join(self._temp_dir, self._name + 
> ".log")
> +        self._qemu_log_file = open(self._qemu_log_path, 'wb')
> +
>          self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address,
>                                                  server=True)
>  
> @@ -180,23 +191,28 @@ class QEMUMachine(object):
>          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)
> +        if self._qemu_log_file is not None:
> +            self._qemu_log_file.close()
> +            self._qemu_log_file = None
> +
> +        self._qemu_log_path = None
> +
> +        if self._temp_dir is not None:
> +            shutil.rmtree(self._temp_dir)
> +            self._temp_dir = None
>  
>      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_file,
>                                             stderr=subprocess.STDOUT,
>                                             shell=False)
>              self._post_launch()
> -- 
> 2.13.6
> 
> 

-- 
Eduardo