[libvirt] [PATCH] util: storage: Fix crash of libvirtd on network backed guest block-pull

[Peter Krempa]

For guests backed by gluster volumes (or other network storage) we don't
fill the backing chain (see qemuDomainDetermineDiskChain). This leaves
the "relPath" field of the top image NULL. This causes a crash in
virStorageFileChainLookup() when looking up a backing element for such a
disk.

Since I'm working on adding support for network storage and one of the
steps will make the "relPath" field optional let's use STREQ_NULLABLE
instead of STREQ in virStorageFileChainLookup() to avoid the problem.
---
 src/util/virstoragefile.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 2feda67..c9b6187 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -1591,7 +1591,7 @@ virStorageFileChainLookup(virStorageSourcePtr chain,
             if (idx == i)
                 break;
         } else {
-            if (STREQ(name, chain->relPath))
+            if (STREQ_NULLABLE(name, chain->relPath))
                 break;
             if (nameIsFile && (chain->type == VIR_STORAGE_TYPE_FILE ||
                                chain->type == VIR_STORAGE_TYPE_BLOCK)) {
-- 
1.9.3