mini-os: netfront: Handle init failure when no vifs are provided

These changes deal with the case when no vifs are created. This can happen when
no vif is provided in the config file for mini-os images with netfront support.

Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Samuel Thibault <samuel.thibault@@ens-lyon.org>

diff --git a/lwip-net.c b/lwip-net.c
index 7e0d8719577e32d76623253da91343071018fc28..16950d322d66521dcc069cde2f33072f24a3e7b4 100644 (file)
--- a/lwip-net.c
+++ b/lwip-net.c
@@ -348,6 +348,10 @@ void start_networking(void)
   tprintk("Waiting for network.\n");
 
   dev = init_netfront(NULL, NULL, rawmac, &ip);
+  if (!dev) {
+      tprintk("Error initializing netfront.\n");
+      return;
+  }
   netmask_str = netfront_get_netmask(dev);
   gw_str = netfront_get_gateway(dev);
   

diff --git a/netfront.c b/netfront.c
index 20754102566fdbbd92d7e5ce16f9e2e33f448b13..f927e99cd501009ab84d6b08dcd57645f1e48f5f 100644 (file)
--- a/netfront.c
+++ b/netfront.c
@@ -383,6 +383,7 @@ char *netfront_get_gateway(struct netfront_dev *dev)
 
 static struct netfront_dev *_init_netfront(struct netfront_dev *dev)
 {
+    int domid;
     xenbus_transaction_t xbt;
     char* err = NULL;
     char* message=NULL;
@@ -393,6 +394,12 @@ static struct netfront_dev *_init_netfront(struct netfront_dev *dev)
     int i;
     char path[256];
 
+    snprintf(path, sizeof(path), "%s/backend-id", dev->nodename);
+    domid = xenbus_read_integer(path);
+    if (domid < 0)
+        return NULL;
+    dev->dom = domid;
+
     printk("net TX ring size %lu\n", (unsigned long) NET_TX_RING_SIZE);
     printk("net RX ring size %lu\n", (unsigned long) NET_RX_RING_SIZE);
     init_SEMAPHORE(&dev->tx_sem, NET_TX_RING_SIZE);
@@ -407,8 +414,6 @@ static struct netfront_dev *_init_netfront(struct netfront_dev *dev)
         BUG_ON(dev->rx_buffers[i].page == NULL);
     }
 
-    snprintf(path, sizeof(path), "%s/backend-id", dev->nodename);
-    dev->dom = xenbus_read_integer(path);
 #ifdef HAVE_LIBC
     if (dev->netif_rx == NETIF_SELECT_RX)
         evtchn_alloc_unbound(dev->dom, netfront_select_handler, dev, &dev->evtchn);