fixed memory leak: CURLOPT_RESOLVE with multi interface

DNS cache entries populated with CURLOPT_RESOLVE were not properly freed
again when done using the multi interface.

Test case 1502 added to verify.

Bug: http://curl.haxx.se/bug/view.cgi?id=3575448
Reported by: Alex Gruz

3 files changed, 19 insertions, 12 deletions

diff --git a/lib/hostip.c b/lib/hostip.c
index 503ba483f..ef14ce863 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -740,14 +740,18 @@ static int hostcache_inuse(void *data, void *hc)
   return 1; /* free all entries */
 }
 
-void Curl_hostcache_destroy(struct SessionHandle *data)
+void Curl_hostcache_clean(struct SessionHandle *data)
 {
   /* Entries added to the hostcache with the CURLOPT_RESOLVE function are
    * still present in the cache with the inuse counter set to 1. Detect them
    * and cleanup!
    */
   Curl_hash_clean_with_criterium(data->dns.hostcache, data, hostcache_inuse);
+}
 
+void Curl_hostcache_destroy(struct SessionHandle *data)
+{
+  Curl_hostcache_clean(data);
   Curl_hash_destroy(data->dns.hostcache);
   data->dns.hostcachetype = HCACHE_NONE;
   data->dns.hostcache = NULL;
diff --git a/lib/hostip.h b/lib/hostip.h
index 12fb80f54..de71f54f4 100644
--- a/lib/hostip.h
+++ b/lib/hostip.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -201,10 +201,18 @@ extern sigjmp_buf curl_jmpenv;
 CURLcode Curl_set_dns_servers(struct SessionHandle *data, char *servers);
 
 /*
+ * Clean off entries from the cache
+ */
+void Curl_hostcache_clean(struct SessionHandle *data);
+
+/*
  * Destroy the hostcache of this handle.
  */
 void Curl_hostcache_destroy(struct SessionHandle *data);
 
+/*
+ * Populate the cache with specified entries from CURLOPT_RESOLVE.
+ */
 CURLcode Curl_loadhostpairs(struct SessionHandle *data);
 
 #endif /* HEADER_CURL_HOSTIP_H */
diff --git a/lib/multi.c b/lib/multi.c
index 938846769..b4e01bd93 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -1789,12 +1789,6 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
   } WHILE_FALSE; /* just to break out from! */
 
   if(CURLM_STATE_COMPLETED == easy->state) {
-    if(data->dns.hostcachetype == HCACHE_MULTI) {
-      /* clear out the usage of the shared DNS cache */
-      data->dns.hostcache = NULL;
-      data->dns.hostcachetype = HCACHE_NONE;
-    }
-
     /* now fill in the Curl_message with this info */
     msg = &easy->msg;
 
@@ -1911,9 +1905,6 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
       cl= n;
     }
 
-    Curl_hash_destroy(multi->hostcache);
-    multi->hostcache = NULL;
-
     Curl_hash_destroy(multi->sockhash);
     multi->sockhash = NULL;
 
@@ -1930,6 +1921,7 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
       nexteasy=easy->next;
       if(easy->easy_handle->dns.hostcachetype == HCACHE_MULTI) {
         /* clear out the usage of the shared DNS cache */
+        Curl_hostcache_clean(easy->easy_handle);
         easy->easy_handle->dns.hostcache = NULL;
         easy->easy_handle->dns.hostcachetype = HCACHE_NONE;
       }
@@ -1943,6 +1935,9 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
       easy = nexteasy;
     }
 
+    Curl_hash_destroy(multi->hostcache);
+    multi->hostcache = NULL;
+
     free(multi);
 
     return CURLM_OK;