libglusterfs: fix dict leak

Problem:
gf_rev_dns_lookup_cached() allocated struct dnscache->dict if it was null
but the freeing was left to the caller.

Fix:
Moved dict allocation and freeing into corresponding init and fini
routines so that its easier for the caller to avoid such leaks.

Updates: #1000
Change-Id: I90d6a6f85ca2dd4fe0ab461177aaa9ac9c1fbcf9
Signed-off-by: Ravishankar N <ravishankar@redhat.com>

libglusterfs/src/common-utils.c

@@ -577,14 +577,34 @@ struct dnscache *
 gf_dnscache_init(time_t ttl)
 {
     struct dnscache *cache = GF_MALLOC(sizeof(*cache), gf_common_mt_dnscache);
-    if (cache) {
-        cache->cache_dict = NULL;
+    if (!cache)
+        return NULL;
+
+    cache->cache_dict = dict_new();
+    if (!cache->cache_dict) {
+        GF_FREE(cache);
+        cache = NULL;
+    } else {
         cache->ttl = ttl;
     }
 
     return cache;
 }
 
+/**
+ * gf_dnscache_deinit -- cleanup resources used by struct dnscache
+ */
+void
+gf_dnscache_deinit(struct dnscache *cache)
+{
+    if (!cache) {
+        gf_msg_plain(GF_LOG_WARNING, "dnscache is NULL");
+        return;
+    }
+    dict_unref(cache->cache_dict);
+    GF_FREE(cache);
+}
+
 /**
  * gf_dnscache_entry_init -- Initialize a dnscache entry
  *
@@ -633,12 +653,6 @@ gf_rev_dns_lookup_cached(const char *ip, struct dnscache *dnscache)
     if (!dnscache)
         goto out;
 
-    if (!dnscache->cache_dict) {
-        dnscache->cache_dict = dict_new();
-        if (!dnscache->cache_dict) {
-            goto out;
-        }
-    }
     cache = dnscache->cache_dict;
 
     /* Quick cache lookup to see if we already hold it */

libglusterfs/src/glusterfs/common-utils.h

@@ -255,6 +255,8 @@ list_node_del(struct list_node *node);
 
 struct dnscache *
 gf_dnscache_init(time_t ttl);
+void
+gf_dnscache_deinit(struct dnscache *cache);
 struct dnscache_entry *
 gf_dnscache_entry_init(void);
 void

libglusterfs/src/libglusterfs.sym

@@ -585,6 +585,7 @@ gf_dirent_free
 gf_dirent_orig_offset
 gf_dm_hashfn
 gf_dnscache_init
+gf_dnscache_deinit
 gf_errno_to_error
 gf_error_to_errno
 _gf_event

xlators/debug/io-stats/src/io-stats.c

@@ -3838,7 +3838,7 @@ ios_conf_destroy(struct ios_conf *conf)
     _ios_destroy_dump_thread(conf);
     ios_destroy_sample_buf(conf->ios_sample_buf);
     LOCK_DESTROY(&conf->lock);
-    GF_FREE(conf->dnscache);
+    gf_dnscache_deinit(conf->dnscache);
     GF_FREE(conf);
 }
 
@@ -3950,11 +3950,14 @@ init(xlator_t *this)
         gf_log(this->name, GF_LOG_ERROR, "Out of memory.");
         goto out;
     }
-    ret = -1;
 
     GF_OPTION_INIT("ios-dnscache-ttl-sec", conf->ios_dnscache_ttl_sec, int32,
                    out);
     conf->dnscache = gf_dnscache_init(conf->ios_dnscache_ttl_sec);
+    if (!conf->dnscache) {
+        ret = -1;
+        goto out;
+    }
 
     GF_OPTION_INIT("sys-log-level", sys_log_str, str, out);
     if (sys_log_str) {