[libvirt] [PATCH 2/2] hotplug: fix char device detach

[Pavel Hrdina]

Hotplugging and hotunplugging char devices is only supported through
'-device' and the check for device capability should be independently.

Coverity also complains about 'tmpChr->info.alias' could be NULL and we
are dereferencing it but it somehow only in this case don't recognize
that the value is set by 'qemuAssignDeviceChrAlias' so it's clearly
false positive. Add comment to skip this error in this case.

Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
---
 src/qemu/qemu_hotplug.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index d3bf392..520c0db 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -3713,18 +3713,22 @@ int qemuDomainDetachChrDevice(virQEMUDriverPtr driver,
         return ret;
     }
 
-    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE) &&
-        !tmpChr->info.alias) {
-        if (qemuAssignDeviceChrAlias(vmdef, tmpChr, -1) < 0)
-            return ret;
+    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("qemu does not support -device"));
+        return ret;
     }
 
+    if (!tmpChr->info.alias && qemuAssignDeviceChrAlias(vmdef, tmpChr, -1) < 0)
+        return ret;
+
     if (qemuBuildChrDeviceStr(&devstr, vm->def, chr, priv->qemuCaps) < 0)
         return ret;
 
     qemuDomainMarkDeviceForRemoval(vm, &tmpChr->info);
 
     qemuDomainObjEnterMonitor(driver, vm);
+    /* coverity[var_deref_model] */
     if (devstr && qemuMonitorDelDevice(priv->mon, tmpChr->info.alias) < 0) {
         qemuDomainObjExitMonitor(driver, vm);
         goto cleanup;
-- 
2.0.4