Re: [Qemu-devel] [PATCH v2 4/5] scripts/qemu.py: introduce set_console() method

[Cleber Rosa]

On 05/26/2018 12:54 AM, Philippe Mathieu-Daudé wrote:
> Hi Cleber,
> 
> On 05/25/2018 03:42 PM, Cleber Rosa wrote:
>> The set_console() method is intended to ease higher level use cases
>> that require a console device.
>>
>> The amount of intelligence is limited on purpose, requiring either the
>> device type explicitly, or the existence of a machine (pattern)
>> definition.
>>
>> Because of the console device type selection criteria (by machine
>> type), users should also be able to define that.  It'll then be used
>> for both '-machine' and for the console device type selection.
>>
>> Users of the set_console() method will certainly be interested in
>> accessing the console device, and for that a console_socket property
>> has been added.
>>
>> Signed-off-by: Cleber Rosa <address@hidden>
>> ---
>>  scripts/qemu.py      |  97 +++++++++++++++++++++-
>>  scripts/test_qemu.py | 186 +++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 282 insertions(+), 1 deletion(-)
>>  create mode 100644 scripts/test_qemu.py
>>
>> diff --git a/scripts/qemu.py b/scripts/qemu.py
>> index 7cd8193df8..f099ce7278 100644
>> --- a/scripts/qemu.py
>> +++ b/scripts/qemu.py
>> @@ -17,19 +17,41 @@ import logging
>>  import os
>>  import subprocess
>>  import qmp.qmp
>> +import re
>>  import shutil
>> +import socket
>>  import tempfile
>>  
>>  
>>  LOG = logging.getLogger(__name__)
>>  
>>  
>> +#: Maps machine types to the preferred console device types
> 
> This could be QMP query-able...
> 

I'm not an expert here, but IIRC Eduardo thinks that the best solution
may be for these machine types to implement support for "-serial"
instead.  When all machines do that, then this "set_console()" would
default to adding a "-serial" argument if no device type is given.

>> +CONSOLE_DEV_TYPES = {
>> +    r'^clipper$': 'isa-serial',
>> +    r'^malta': 'isa-serial',
>> +    r'^(pc.*|q35.*|isapc)$': 'isa-serial',
>> +    r'^(40p|powernv|prep)$': 'isa-serial',
>> +    r'^pseries.*': 'spapr-vty',
>> +    r'^s390-ccw-virtio.*': 'sclpconsole',
>> +    }
>> +
>> +
>>  class QEMUMachineError(Exception):
>>      """
>>      Exception called when an error in QEMUMachine happens.
>>      """
>>  
>>  
>> +class QEMUMachineAddDeviceError(QEMUMachineError):
>> +    """
>> +    Exception raised when a request to add a device can not be fulfilled
>> +
>> +    The failures are caused by limitations, lack of information or 
>> conflicting
>> +    requests on the QEMUMachine methods.  This exception does not represent
>> +    failures reported by the QEMU binary itself.
>> +    """
>> +
>>  class MonitorResponseError(qmp.qmp.QMPError):
>>      '''
>>      Represents erroneous QMP monitor reply
>> @@ -91,6 +113,10 @@ class QEMUMachine(object):
>>          self._test_dir = test_dir
>>          self._temp_dir = None
>>          self._launched = False
>> +        self._machine = None
>> +        self._console_device_type = None
>> +        self._console_address = None
>> +        self._console_socket = None
>>  
>>          # just in case logging wasn't configured by the main script:
>>          logging.basicConfig()
>> @@ -175,9 +201,19 @@ class QEMUMachine(object):
>>                  self._monitor_address[1])
>>          else:
>>              moncdev = 'socket,id=mon,path=%s' % self._vm_monitor
>> -        return ['-chardev', moncdev,
>> +        args = ['-chardev', moncdev,
>>                  '-mon', 'chardev=mon,mode=control',
>>                  '-display', 'none', '-vga', 'none']
>> +        if self._machine is not None:
>> +            args.extend(['-machine', self._machine])
>> +        if self._console_device_type is not None:
>> +            self._console_address = os.path.join(self._temp_dir,
>> +                                                 self._name + 
>> "-console.sock")
>> +            chardev = ('socket,id=console,path=%s,server,nowait' %
>> +                       self._console_address)
>> +            device = '%s,chardev=console' % self._console_device_type
>> +            args.extend(['-chardev', chardev, '-device', device])
>> +        return args
>>  
>>      def _pre_launch(self):
>>          self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
>> @@ -202,6 +238,10 @@ class QEMUMachine(object):
>>  
>>          self._qemu_log_path = None
>>  
>> +        if self._console_socket is not None:
>> +            self._console_socket.close()
>> +            self._console_socket = None
>> +
>>          if self._temp_dir is not None:
>>              shutil.rmtree(self._temp_dir)
>>              self._temp_dir = None
>> @@ -365,3 +405,58 @@ class QEMUMachine(object):
>>          Adds to the list of extra arguments to be given to the QEMU binary
>>          '''
>>          self._args.extend(args)
>> +
>> +    def set_machine(self, machine_type):
>> +        '''
>> +        Sets the machine type
>> +
>> +        If set, the machine type will be added to the base arguments
>> +        of the resulting QEMU command line.
>> +        '''
>> +        self._machine = machine_type
>> +
>> +    def set_console(self, device_type=None):
>> +        '''
>> +        Sets the device type for a console device
>> +
>> +        If set, the console device and a backing character device will
>> +        be added to the base arguments of the resulting QEMU command
>> +        line.
>> +
>> +        This is a convenience method that will either use the provided
>> +        device type, of if not given, it will used the device type set
>> +        on CONSOLE_DEV_TYPES.
>> +
>> +        The actual setting of command line arguments will be be done at
>> +        machine launch time, as it depends on the temporary directory
>> +        to be created.
>> +
>> +        @param device_type: the device type, such as "isa-serial"
>> +        @raises: QEMUMachineAddDeviceError if the device type is not given
>> +                 and can not be determined.
>> +        '''
>> +        if device_type is None:
>> +            if self._machine is None:
>> +                raise QEMUMachineAddDeviceError("Can not add a console 
>> device:"
>> +                                                " QEMU instance without a "
>> +                                                "defined machine type")
>> +            for regex, device in CONSOLE_DEV_TYPES.items():
>> +                if re.match(regex, self._machine):
>> +                    device_type = device
>> +                    break
>> +            if device_type is None:
>> +                raise QEMUMachineAddDeviceError("Can not add a console 
>> device:"
>> +                                                " no matching console 
>> device "
>> +                                                "type definition")
>> +        self._console_device_type = device_type
>> +
>> +    @property
>> +    def console_socket(self):
>> +        """
>> +        Returns a socket connected to the console
>> +        """
>> +        if self._console_socket is None:
>> +            self._console_socket = socket.socket(socket.AF_UNIX,
>> +                                                 socket.SOCK_STREAM)
>> +            self._console_socket.connect(self._console_address)
>> +        return self._console_socket
>> diff --git a/scripts/test_qemu.py b/scripts/test_qemu.py
>> new file mode 100644
>> index 0000000000..a5874fd217
>> --- /dev/null
>> +++ b/scripts/test_qemu.py
>> @@ -0,0 +1,186 @@
>> +# Tests and utilities for testing for "qemu.py" functionality
>> +#
>> +# Copyright (c) 2018 Red Hat, Inc.
>> +#
>> +# Author:
>> +#  Cleber Rosa <address@hidden>
>> +#
>> +# This work is licensed under the terms of the GNU GPL, version 2 or
>> +# later.  See the COPYING file in the top-level directory.
>> +
>> +import sys
>> +import os
>> +import glob
>> +import unittest
>> +import shutil
>> +import tempfile
>> +import subprocess
>> +
>> +import qemu
>> +import qmp.qmp
>> +
>> +
>> +class QEMUMachineProbeError(Exception):
>> +    """
>> +    Exception raised when a probe a fails to be deterministic
>> +    """
>> +
>> +
>> +def get_built_qemu_binaries(root_dir=None):
>> +    """
>> +    Attempts to find QEMU binaries in a tree
>> +
>> +    If root_dir is None, it will attempt to find the binaries at the
>> +    source tree.  It's possible to override it by setting the environment
>> +    variable QEMU_ROOT_DIR.
>> +    """
>> +    if root_dir is None:
>> +        src_dir = 
>> os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
>> +        root_dir = os.environ.get("QEMU_ROOT_DIR", src_dir)
>> +    binaries = glob.glob(os.path.join(root_dir, '*-softmmu/qemu-system-*'))
>> +    if 'win' in sys.platform:
>> +        bin_filter = lambda x: x.endswith(".exe")
>> +    else:
>> +        bin_filter = lambda x: not x.endswith(".exe")
>> +    return [_ for _ in binaries if bin_filter(_)]
>> +
>> +
>> +def subprocess_dev_null(mode='w'):
>> +    """
>> +    A portable null file object suitable for use with the subprocess module
>> +    """
>> +    if hasattr(subprocess, 'DEVNULL'):
>> +        return subprocess.DEVNULL
>> +    else:
>> +        return open(os.path.devnull, mode)
>> +
>> +
>> +def qmp_execute(binary_path, qmp_command):
>> +    """
>> +    Executes a QMP command on a given QEMU binary
>> +
>> +    Useful for one-off execution of QEMU binaries to get runtime
>> +    information.
>> +
>> +    @param binary_path: path to a QEMU binary
>> +    @param qmp_command: the QMP command
>> +    @note: passing arguments to the QMP command is not supported at
>> +           this time.
>> +    """
>> +    try:
>> +        tempdir = tempfile.mkdtemp()
>> +        monitor_socket = os.path.join(tempdir, 'monitor.sock')
>> +        args = [binary_path, '-nodefaults', '-machine', 'none',
>> +                '-nographic', '-S', '-qmp', 'unix:%s' % monitor_socket]
>> +        monitor = qmp.qmp.QEMUMonitorProtocol(monitor_socket, True)
>> +        try:
>> +            qemu_proc = subprocess.Popen(args,
>> +                                         stdin=subprocess.PIPE,
>> +                                         stdout=subprocess.PIPE,
>> +                                         stderr=subprocess_dev_null(),
>> +                                         universal_newlines=True)
>> +        except OSError:
>> +            return None
>> +        monitor.accept()
>> +        res = monitor.cmd(qmp_command)
>> +        monitor.cmd("quit")
>> +        qemu_proc.wait()
>> +        monitor.close()
>> +        return res.get("return", None)
>> +    finally:
>> +        shutil.rmtree(tempdir)
>> +
>> +
>> +def qemu_bin_probe_arch(binary_path):
>> +    """
>> +    Probes the architecture from the QEMU binary
>> +
>> +    @returns: either the probed arch or None
>> +    @rtype: str or None
>> +    @raises: QEMUMachineProbeError
>> +    """
>> +    res = qmp_execute(binary_path, "query-target")
>> +    if res is None:
>> +        raise QEMUMachineProbeError('Failed to probe the QEMU arch by 
>> querying'
>> +                                    ' the target of binary "%s"' % 
>> binary_path)
>> +    return res.get("arch", None)
>> +
>> +
>> +class QEMU(unittest.TestCase):
>> +
>> +
>> +    TEST_ARCH_MACHINE_CONSOLES = {
> 
> I think this dictionary should be auto-generated, at worst previously to
> tag a release.
> 

I can look into that, but I think it would only be significant if/when a
Makefile target that runs this test regularly is also addressed.  Should
we have a "make check-scripts-own-tests" sort of rule?

- Cleber.

>> +        'alpha': ['clipper'],
>> +        'mips': ['malta'],
>> +        'x86_64': ['isapc',
>> +                   'pc', 'pc-0.10', 'pc-0.11', 'pc-0.12', 'pc-0.13',
>> +                   'pc-0.14', 'pc-0.15', 'pc-1.0', 'pc-1.1', 'pc-1.2',
>> +                   'pc-1.3',
>> +                   'pc-i440fx-1.4', 'pc-i440fx-1.5', 'pc-i440fx-1.6',
>> +                   'pc-i440fx-1.7', 'pc-i440fx-2.0', 'pc-i440fx-2.1',
>> +                   'pc-i440fx-2.10', 'pc-i440fx-2.11', 'pc-i440fx-2.2',
>> +                   'pc-i440fx-2.3', 'pc-i440fx-2.4', 'pc-i440fx-2.5',
>> +                   'pc-i440fx-2.6', 'pc-i440fx-2.7', 'pc-i440fx-2.8',
>> +                   'pc-i440fx-2.9', 'pc-q35-2.10', 'pc-q35-2.11',
>> +                   'q35', 'pc-q35-2.4', 'pc-q35-2.5', 'pc-q35-2.6',
>> +                   'pc-q35-2.7', 'pc-q35-2.8', 'pc-q35-2.9'],
>> +        'ppc64': ['40p', 'powernv', 'prep', 'pseries', 'pseries-2.1',
>> +                  'pseries-2.2', 'pseries-2.3', 'pseries-2.4', 
>> 'pseries-2.5',
>> +                  'pseries-2.6', 'pseries-2.7', 'pseries-2.8', 
>> 'pseries-2.9',
>> +                  'pseries-2.10', 'pseries-2.11', 'pseries-2.12'],
>> +        's390x': ['s390-ccw-virtio', 's390-ccw-virtio-2.4',
>> +                  's390-ccw-virtio-2.5', 's390-ccw-virtio-2.6',
>> +                  's390-ccw-virtio-2.7', 's390-ccw-virtio-2.8',
>> +                  's390-ccw-virtio-2.9', 's390-ccw-virtio-2.10',
>> +                  's390-ccw-virtio-2.11', 's390-ccw-virtio-2.12']
>> +    }
>> +
>> +
>> +    def test_set_console(self):
>> +        for machines in QEMU.TEST_ARCH_MACHINE_CONSOLES.values():
>> +            for machine in machines:
>> +                qemu_machine = qemu.QEMUMachine('/fake/path/to/binary')
>> +                qemu_machine.set_machine(machine)
>> +                qemu_machine.set_console()
>> +
>> +    def test_set_console_no_machine(self):
>> +        qemu_machine = qemu.QEMUMachine('/fake/path/to/binary')
>> +        self.assertRaises(qemu.QEMUMachineAddDeviceError,
>> +                          qemu_machine.set_console)
>> +
>> +    def test_set_console_no_machine_match(self):
>> +        qemu_machine = qemu.QEMUMachine('/fake/path/to/binary')
>> +        qemu_machine.set_machine('unknown-machine-model')
>> +        self.assertRaises(qemu.QEMUMachineAddDeviceError,
>> +                          qemu_machine.set_console)
>> +
>> +    @unittest.skipUnless(get_built_qemu_binaries(),
>> +                         "Could not find any QEMU binaries built to use on "
>> +                         "console check")
>> +    def test_set_console_launch(self):
>> +        for binary in get_built_qemu_binaries():
>> +            probed_arch = qemu_bin_probe_arch(binary)
>> +            for machine in QEMU.TEST_ARCH_MACHINE_CONSOLES.get(probed_arch, 
>> []):
>> +                qemu_machine = qemu.QEMUMachine(binary)
>> +
>> +                # the following workarounds are target specific required for
>> +                # this test.  users are of QEMUMachine are expected to deal 
>> with
>> +                # target specific requirements just the same in their own 
>> code
>> +                cap_htm_off = ('pseries-2.7', 'pseries-2.8', 'pseries-2.9',
>> +                               'pseries-2.10', 'pseries-2.11', 
>> 'pseries-2.12')
>> +                if probed_arch == 'ppc64' and machine in cap_htm_off:
>> +                    qemu_machine._machine = machine   # pylint: 
>> disable=W0212
>> +                    qemu_machine.args.extend(['-machine',
>> +                                              '%s,cap-htm=off' % machine])
>> +                elif probed_arch == 's390x':
>> +                    qemu_machine.set_machine(machine)
>> +                    qemu_machine.args.append('-nodefaults')
>> +                elif probed_arch == 'mips':
>> +                    qemu_machine.set_machine(machine)
>> +                    qemu_machine.args.extend(['-bios', os.path.devnull])
>> +                else:
>> +                    qemu_machine.set_machine(machine)
>> +
>> +                qemu_machine.set_console()
>> +                qemu_machine.launch()
>> +                qemu_machine.shutdown()
>>
>