conf: utility function to update entry in def->nets array

A virDomainNetDef object in a domain's nets array might contain a
virDomainHostdevDef, and when this is the case, the domain's hostdevs
array will also have a pointer to this embedded hostdev (this is done
so that internal functions that need to perform some operation on all
hostdevs won't leave out the type='hostdev' network interfaces).

When a network device was updated with virDomainUpdateDeviceFlags(),
we were replacing the entry in the nets array (and free'ing the
original) but forgetting about the pointer in the hostdevs array
(which would then point to the now-free'd hostdev contained in the old
net object.) This often resulted in a libvirtd crash.

The solution is to add a function, virDomainNetUpdate(), called by
qemuDomainUpdateDeviceConfig(), that updates the hostdevs array
appropriately along with the nets array.

Resolves: https://bugzilla.redhat.com/1558934

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index c290baf953c95eb5a5843ccaca64cdf45ef77c23..7d83a3d1c639852da59cd54d989c562b1c44bc65 100644 (file)
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -17169,6 +17169,47 @@ virDomainNetRemove(virDomainDefPtr def, size_t i)
     return net;
 }
 
+
+int
+virDomainNetUpdate(virDomainDefPtr def,
+                   size_t netidx,
+                   virDomainNetDefPtr newnet)
+{
+    size_t hostdevidx;
+    virDomainNetDefPtr oldnet = def->nets[netidx];
+    virDomainHostdevDefPtr oldhostdev = virDomainNetGetActualHostdev(oldnet);
+    virDomainHostdevDefPtr newhostdev = virDomainNetGetActualHostdev(newnet);
+
+    /*
+     * if newnet or oldnet has a valid hostdev*, we need to update the
+     * hostdevs list
+     */
+    if (oldhostdev) {
+        for (hostdevidx = 0; hostdevidx < def->nhostdevs; hostdevidx++) {
+            if (def->hostdevs[hostdevidx] == oldhostdev)
+                break;
+        }
+    }
+
+    if (oldhostdev && hostdevidx < def->nhostdevs) {
+        if (newhostdev) {
+            /* update existing entry in def->hostdevs */
+            def->hostdevs[hostdevidx] = newhostdev;
+        } else {
+            /* delete oldhostdev from def->hostdevs */
+            virDomainHostdevRemove(def, hostdevidx);
+        }
+    } else if (newhostdev) {
+        /* add newhostdev to end of def->hostdevs */
+        if (VIR_APPEND_ELEMENT(def->hostdevs, def->nhostdevs, newhostdev) < 0)
+            return -1;
+    }
+
+    def->nets[netidx] = newnet;
+    return 0;
+}
+
+
 int virDomainControllerInsert(virDomainDefPtr def,
                               virDomainControllerDefPtr controller)
 {

diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 53bdee22fb1b3c5abc07e36df31478a9ed53147e..2884af49d8c31be3bb6d0f39be943953e28679f7 100644 (file)
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -3174,6 +3174,7 @@ virDomainNetDefPtr virDomainNetFind(virDomainDefPtr def, const char *device);
 virDomainNetDefPtr virDomainNetFindByName(virDomainDefPtr def, const char *ifname);
 bool virDomainHasNet(virDomainDefPtr def, virDomainNetDefPtr net);
 int virDomainNetInsert(virDomainDefPtr def, virDomainNetDefPtr net);
+int virDomainNetUpdate(virDomainDefPtr def, size_t netidx, virDomainNetDefPtr newnet);
 virDomainNetDefPtr virDomainNetRemove(virDomainDefPtr def, size_t i);
 void virDomainNetRemoveHostdev(virDomainDefPtr def, virDomainNetDefPtr net);
 

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 287e63bffa58eeb22a9d02b054b0a0c3b0ce647e..2b10a1030e7413ed267d630cd48c06290e8ae298 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -508,6 +508,7 @@ virDomainNetSetModelString;
 virDomainNetTypeFromString;
 virDomainNetTypeSharesHostView;
 virDomainNetTypeToString;
+virDomainNetUpdate;
 virDomainNostateReasonTypeFromString;
 virDomainNostateReasonTypeToString;
 virDomainObjAssignDef;

diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index 5453f49064c8e981e22a82b9d732f8c9e62f68e5..cf1dd1428e48035bb0a67043b109bdc3048a71f5 100644 (file)
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -3486,8 +3486,10 @@ lxcDomainUpdateDeviceConfig(virDomainDefPtr vmdef,
                                          false) < 0)
             return -1;
 
-        virDomainNetDefFree(vmdef->nets[idx]);
-        vmdef->nets[idx] = net;
+        if (virDomainNetUpdate(vmdef, idx, net) < 0)
+            return -1;
+
+        virDomainNetDefFree(oldDev.data.net);
         dev->data.net = NULL;
         ret = 0;
 

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 0c65414a1a3cdb7312e1a9e2ee2662196333b250..286f5bd9846931425bae8447480a45580ae34326 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -8786,8 +8786,10 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef,
                                          false) < 0)
             return -1;
 
-        virDomainNetDefFree(vmdef->nets[pos]);
-        vmdef->nets[pos] = net;
+        if (virDomainNetUpdate(vmdef, pos, net))
+            return -1;
+
+        virDomainNetDefFree(oldDev.data.net);
         dev->data.net = NULL;
         break;