[virt-tools-list] [PATCH v2] domain: add 'pre-startup' signal and do nodedevs checking

[Guannan Ren]

This patch introduces 'pre-start' signal and registers
nodedev checking handler to check duplicate USB devices.
If virt-manager can not identify unique usb device any more
before domain startup, it will throw a tip error to tell it
is time to reattach host USB devices to get updated bus/addr info.
---
 virtManager/domain.py | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/virtManager/domain.py b/virtManager/domain.py
index 791f2af..26cff37 100644
--- a/virtManager/domain.py
+++ b/virtManager/domain.py
@@ -149,6 +149,7 @@ class vmmDomain(vmmLibvirtObject):
         "status-changed": (GObject.SignalFlags.RUN_FIRST, None, [int, int]),
         "resources-sampled": (GObject.SignalFlags.RUN_FIRST, None, []),
         "inspection-changed": (GObject.SignalFlags.RUN_FIRST, None, []),
+        "pre-startup": (GObject.SignalFlags.RUN_FIRST, None, [])
     }
 
     def __init__(self, conn, backend, uuid):
@@ -194,6 +195,9 @@ class vmmDomain(vmmLibvirtObject):
         self._stats_disk_supported = True
         self._stats_disk_skip = []
 
+        # pre_startup global flags
+        self._prestartup_hostdev_check_failed = False
+
         self.inspection = vmmInspectionData()
 
         if isinstance(self._backend, virtinst.Guest):
@@ -252,7 +256,59 @@ class vmmDomain(vmmLibvirtObject):
 
         self.connect("status-changed", self._update_start_vcpus)
         self.connect("config-changed", self._reparse_xml)
+        self.connect("pre-startup", self._prestartup_nodedev_check)
+
+    #####################
+    # checking routines #
+    #####################
+
+    def attrVal(self, attr):
+        if hasattr(self, attr):
+            return getattr(self, attr)
+        return False
+
+    # class closure to initialize global variable.
+    def do_pre_startup(self):
+        if getattr(self, "_prestartup_hostdev_check_failed"):
+            self._prestartup_hostdev_check_failed = False
+            # Initialize falure reasons
+            self._hostdev_non_exist = False
+            self._hostdev_multiples = False
 
+    def _prestartup_nodedev_check(self, data=None):
+        for hostdev in self.get_hostdev_devices():
+            devtype = hostdev.type
+
+            if devtype != "usb":
+                continue
+
+            vendor = hostdev.vendor
+            product = hostdev.product
+            bus = hostdev.bus
+            device = hostdev.device
+
+            if vendor and product:
+                count = self.conn.get_nodedevs_number("usb_device",
+                                                      vendor,
+                                                      product)
+                if not count:
+                    self._prestartup_hostdev_check_failed = True
+                    self._hostdev_non_exist = True
+
+                elif count > 1 and not (bus and device):
+                    self._prestartup_hostdev_check_failed = True
+                    self._hostdev_multiples = True
+
+    def _prestartup_nodedev_report(self):
+        if self._prestartup_hostdev_check_failed:
+            if self.attrVal("_hostdev_non_exist"):
+                raise RuntimeError(_("Could not find any USB device"))
+
+            elif self.attrVal("_hostdev_multiples"):
+                raise RuntimeError(_("The attached USB device "
+                                     "is not unique, please remove "
+                                     "and add it again!"))
+        return;
 
     ###########################
     # Misc API getter methods #
@@ -1171,6 +1227,10 @@ class vmmDomain(vmmLibvirtObject):
         if self.get_cloning():
             raise RuntimeError(_("Cannot start guest while cloning "
                                  "operation in progress"))
+
+        self.emit("pre-startup")
+        self._prestartup_nodedev_report()
+
         self._backend.create()
         self.idle_add(self.force_update_status)
 
-- 
1.8.1.4