[libvirt] [PATCH] v2: Fix uninitialized variable & error reporting in LXC veth setup

[Daniel P. Berrange]

THe veth setup in LXC had a couple of flaws, first brInit did
not report any error when it failed. Second vethCreate() did
not correctly initialize the variable containing the return
code, so could report failure even when it succeeded.

* src/lxc/lxc_driver.c: Report error when brInit fails
* src/lxc/veth.c: Fix uninitialized variable
---
 src/lxc/lxc_driver.c |    8 ++++++--
 src/lxc/veth.c       |   33 ++++++++++++++++++++++-----------
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index 79b6879..9b131cc 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -1024,9 +1024,13 @@ static int lxcSetupInterfaces(virConnectPtr conn,
     int rc = -1, i;
     char *bridge = NULL;
     brControl *brctl = NULL;
+    int ret;
 
-    if (brInit(&brctl) != 0)
+    if ((ret = brInit(&brctl)) != 0) {
+        virReportSystemError(ret, "%s",
+                             _("Unable to initialize bridging"));
         return -1;
+    }
 
     for (i = 0 ; i < def->nnets ; i++) {
         char *parentVeth;
@@ -1095,7 +1099,7 @@ static int lxcSetupInterfaces(virConnectPtr conn,
                 goto error_exit;
         }
 
-        if (0 != (rc = brAddInterface(brctl, bridge, parentVeth))) {
+        if ((ret = brAddInterface(brctl, bridge, parentVeth)) != 0) {
             virReportSystemError(rc,
                                  _("Failed to add %s device to %s"),
                                  parentVeth, bridge);
diff --git a/src/lxc/veth.c b/src/lxc/veth.c
index 0fa76cf..26bf4ff 100644
--- a/src/lxc/veth.c
+++ b/src/lxc/veth.c
@@ -90,33 +90,40 @@ static int getFreeVethName(char **veth, int startDev)
  */
 int vethCreate(char** veth1, char** veth2)
 {
-    int rc;
+    int rc = -1;
     const char *argv[] = {
         "ip", "link", "add", NULL, "type", "veth", "peer", "name", NULL, NULL
     };
     int vethDev = 0;
     bool veth1_alloc = false;
+    bool veth2_alloc = false;
 
     VIR_DEBUG("veth1: %s veth2: %s", NULLSTR(*veth1), NULLSTR(*veth2));
 
     if (*veth1 == NULL) {
-        vethDev = getFreeVethName(veth1, vethDev);
-        if (vethDev < 0)
-            return vethDev;
+        if ((vethDev = getFreeVethName(veth1, vethDev)) < 0)
+            goto cleanup;
         VIR_DEBUG("Assigned veth1: %s", *veth1);
         veth1_alloc = true;
     }
     argv[3] = *veth1;
 
-    while (*veth2 == NULL || STREQ(*veth1, *veth2)) {
-        VIR_FREE(*veth2);
-        vethDev = getFreeVethName(veth2, vethDev + 1);
-        if (vethDev < 0) {
+    while (*veth2 == NULL) {
+        if ((vethDev = getFreeVethName(veth2, vethDev + 1)) < 0) {
             if (veth1_alloc)
                 VIR_FREE(*veth1);
-            return vethDev;
+            goto cleanup;
+        }
+
+        /* Just make sure they didn't accidentally get same name */
+        if (STREQ(*veth1, *veth2)) {
+            vethDev++;
+            VIR_FREE(*veth2);
+            continue;
         }
+
         VIR_DEBUG("Assigned veth2: %s", *veth2);
+        veth2_alloc = true;
     }
     argv[8] = *veth2;
 
@@ -124,10 +131,14 @@ int vethCreate(char** veth1, char** veth2)
     if (virRun(argv, NULL) < 0) {
         if (veth1_alloc)
             VIR_FREE(*veth1);
-        VIR_FREE(*veth2);
-        rc = -1;
+        if (veth2_alloc)
+            VIR_FREE(*veth2);
+        goto cleanup;
     }
 
+    rc = 0;
+
+cleanup:
     return rc;
 }
 
-- 
1.7.1