util: string: Add helper to free non-NULL terminated string arrays

To free string lists with some strings stolen from the middle we need to
walk the complete array. Introduce a new helper that takes the string
list size to free such string lists.

src/libvirt_private.syms

@@ -1924,6 +1924,7 @@ virStrcpy;
 virStrdup;
 virStringArrayHasString;
 virStringFreeList;
+virStringFreeListCount;
 virStringJoin;
 virStringListLength;
 virStringReplace;

src/util/virstring.c

@@ -187,6 +187,26 @@ void virStringFreeList(char **strings)
 }
 
 
+/**
+ * virStringFreeListCount:
+ * @strings: array of strings to free
+ * @count: number of elements in the array
+ *
+ * Frees a string array of @count length.
+ */
+void
+virStringFreeListCount(char **strings,
+                       size_t count)
+{
+    size_t i;
+
+    for (i = 0; i < count; i++)
+        VIR_FREE(strings[i]);
+
+    VIR_FREE(strings);
+}
+
+
 bool
 virStringArrayHasString(char **strings, const char *needle)
 {

src/util/virstring.h

@@ -42,6 +42,7 @@ char *virStringJoin(const char **strings,
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
 
 void virStringFreeList(char **strings);
+void virStringFreeListCount(char **strings, size_t count);
 
 bool virStringArrayHasString(char **strings, const char *needle);
 

tests/virstringtest.c

@@ -497,6 +497,26 @@ testStringToLong(const void *opaque)
 }
 
 
+/* The point of this test is to check whether all members of the array are
+ * freed. The test has to be checked using valgrind. */
+static int
+testVirStringFreeListCount(const void *opaque ATTRIBUTE_UNUSED)
+{
+    char **list;
+
+    if (VIR_ALLOC_N(list, 4) < 0)
+        return -1;
+
+    ignore_value(VIR_STRDUP(list[0], "test1"));
+    ignore_value(VIR_STRDUP(list[2], "test2"));
+    ignore_value(VIR_STRDUP(list[3], "test3"));
+
+    virStringFreeListCount(list, 4);
+
+    return 0;
+}
+
+
 static int
 mymain(void)
 {
@@ -701,6 +721,11 @@ mymain(void)
     TEST_STRTOL("-18446744073709551616", NULL, 0, -1, 0U, -1,
                 0LL, -1, 0ULL, -1);
 
+    /* test virStringFreeListCount */
+    if (virtTestRun("virStringFreeListCount", testVirStringFreeListCount,
+                    NULL) < 0)
+        ret = -1;
+
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }