[libvirt] [PATCH] hash: fix memory leak and regression

[Eric Blake]

Commit 1671d1d introduced a memory leak in virHashFree, and
wholesale table corruption in virHashRemoveSet (elements not
requested to be freed are lost).

* src/util/hash.c (virHashFree): Free bucket array.
(virHashRemoveSet): Don't lose elements.
* tests/hashtest.c (testHashCheckForEachCount): New method.
(testHashCheckCount): Expose the bug.
---
 src/util/hash.c  |    6 +++---
 tests/hashtest.c |   15 +++++++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/util/hash.c b/src/util/hash.c
index a9b09b0..5366dd6 100644
--- a/src/util/hash.c
+++ b/src/util/hash.c
@@ -269,6 +269,7 @@ virHashFree(virHashTablePtr table)
         }
     }

+    VIR_FREE(table->table);
     VIR_FREE(table);
 }

@@ -532,13 +533,12 @@ int virHashForEach(virHashTablePtr table, virHashIterator iter, void *data)
  * virHashRemoveSet
  * @table: the hash table to process
  * @iter: callback to identify elements for removal
- * @f: callback to free memory from element payload
  * @data: opaque data to pass to the iterator
  *
  * Iterates over all elements in the hash table, invoking the 'iter'
  * callback. If the callback returns a non-zero value, the element
  * will be removed from the hash table & its payload passed to the
- * callback 'f' for de-allocation.
+ * data freer callback registered at creation.
  *
  * Returns number of items removed on success, -1 on failure
  */
@@ -562,7 +562,7 @@ int virHashRemoveSet(virHashTablePtr table,
         while (*nextptr) {
             virHashEntryPtr entry = *nextptr;
             if (!iter(entry->payload, entry->name, data)) {
-                *nextptr = entry->next;
+                nextptr = &entry->next;
             } else {
                 count++;
                 if (table->dataFree)
diff --git a/tests/hashtest.c b/tests/hashtest.c
index 525ae06..f02b3a9 100644
--- a/tests/hashtest.c
+++ b/tests/hashtest.c
@@ -61,16 +61,31 @@ testHashInit(int size)
     return hash;
 }

+static void
+testHashCheckForEachCount(void *payload ATTRIBUTE_UNUSED,
+                          const void *name ATTRIBUTE_UNUSED,
+                          void *data ATTRIBUTE_UNUSED)
+{
+}

 static int
 testHashCheckCount(virHashTablePtr hash, int count)
 {
+    int iter_count = 0;
+
     if (virHashSize(hash) != count) {
         testError("\nhash contains %d instead of %d elements\n",
                   virHashSize(hash), count);
         return -1;
     }

+    iter_count = virHashForEach(hash, testHashCheckForEachCount, NULL);
+    if (count != iter_count) {
+        testError("\nhash claims to have %d elements but iteration finds %d\n",
+                  count, iter_count);
+        return -1;
+    }
+
     return 0;
 }

-- 
1.7.4.4