global dns cache: didn't work [regression]

CURLOPT_DNS_USE_GLOBAL_CACHE broke in commit c43127414d (been
broken since the libcurl 7.29.0 release). While this option has been
documented as deprecated for almost a decade and nobody even reported
this bug, it should remain functional.

Added test case 1512 to verify

lib/hostip.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2013, 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
@@ -681,12 +681,14 @@ clean_up:
  * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
  * made, the struct may be destroyed due to pruning. It is important that only
  * one unlock is made for each Curl_resolv() call.
+ *
+ * May be called with 'data' == NULL for global cache.
  */
 void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
 {
   DEBUGASSERT(dns && (dns->inuse>0));
 
-  if(data->share)
+  if(data && data->share)
     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
   dns->inuse--;
@@ -697,7 +699,7 @@ void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
     free(dns);
   }
 
-  if(data->share)
+  if(data && data->share)
     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 }
 
@@ -734,22 +736,23 @@ static int hostcache_inuse(void *data, void *hc)
   return 1; /* free all entries */
 }
 
-void Curl_hostcache_clean(struct SessionHandle *data)
+/*
+ * Curl_hostcache_clean()
+ *
+ * This _can_ be called with 'data' == NULL but then of course no locking
+ * can be done!
+ */
+
+void Curl_hostcache_clean(struct SessionHandle *data,
+                          struct curl_hash *hash)
 {
   /* 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);
+  Curl_hash_clean_with_criterium(hash, 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;
-}
 
 CURLcode Curl_loadhostpairs(struct SessionHandle *data)
 {

lib/hostip.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2013, 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
@@ -203,7 +203,7 @@ CURLcode Curl_set_dns_servers(struct SessionHandle *data, char *servers);
 /*
  * Clean off entries from the cache
  */
-void Curl_hostcache_clean(struct SessionHandle *data);
+void Curl_hostcache_clean(struct SessionHandle *data, struct curl_hash *hash);
 
 /*
  * Destroy the hostcache of this handle.

lib/multi.c

@@ -334,7 +334,6 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
                                 CURL *easy_handle)
 {
   struct curl_llist *timeoutlist;
-  struct SessionHandle *easy;
   struct Curl_multi *multi = (struct Curl_multi *)multi_handle;
   struct SessionHandle *data = (struct SessionHandle *)easy_handle;
   struct SessionHandle *new_closure = NULL;
@@ -348,8 +347,8 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
   if(!GOOD_EASY_HANDLE(easy_handle))
     return CURLM_BAD_EASY_HANDLE;
 
-  /* Prevent users from adding same easy handle more than
+  /* Prevent users from adding same easy handle more than once and prevent
-     once and prevent adding to more than one multi stack */
+     adding to more than one multi stack */
   if(data->multi)
     /* possibly we should create a new unique error code for this condition */
     return CURLM_BAD_EASY_HANDLE;
@@ -359,13 +358,11 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
   if(!timeoutlist)
     return CURLM_OUT_OF_MEMORY;
 
-  easy = data;
-
   /* In case multi handle has no hostcache yet, allocate one */
   if(!multi->hostcache) {
     hostcache = Curl_mk_dnscache();
     if(!hostcache) {
-      free(easy);
+      free(data);
       Curl_llist_destroy(timeoutlist, NULL);
       return CURLM_OUT_OF_MEMORY;
     }
@@ -377,7 +374,7 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
     new_closure = (struct SessionHandle *)curl_easy_init();
     if(!new_closure) {
       Curl_hash_destroy(hostcache);
-      free(easy);
+      free(data);
       Curl_llist_destroy(timeoutlist, NULL);
       return CURLM_OUT_OF_MEMORY;
     }
@@ -408,18 +405,28 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
   timeoutlist = NULL;
 
   /* set the easy handle */
-  multistate(easy, CURLM_STATE_INIT);
+  multistate(data, CURLM_STATE_INIT);
 
+  if((data->set.global_dns_cache) &&
+     (data->dns.hostcachetype != HCACHE_GLOBAL)) {
+    /* global dns cache was requested but still isn't */
+    struct curl_hash *global = Curl_global_host_cache_init();
+    if(global) {
+      /* only do this if the global cache init works */
+      data->dns.hostcache = global;
+      data->dns.hostcachetype = HCACHE_GLOBAL;
+    }
+  }
   /* for multi interface connections, we share DNS cache automatically if the
      easy handle's one is currently not set. */
-  if(!easy->dns.hostcache ||
+  else if(!data->dns.hostcache ||
-     (easy->dns.hostcachetype == HCACHE_NONE)) {
+     (data->dns.hostcachetype == HCACHE_NONE)) {
-    easy->dns.hostcache = multi->hostcache;
+    data->dns.hostcache = multi->hostcache;
-    easy->dns.hostcachetype = HCACHE_MULTI;
+    data->dns.hostcachetype = HCACHE_MULTI;
   }
 
   /* Point to the multi's connection cache */
-  easy->state.conn_cache = multi->conn_cache;
+  data->state.conn_cache = multi->conn_cache;
 
   /* This adds the new entry at the 'end' of the doubly-linked circular
      list of SessionHandle structs to try and maintain a FIFO queue so
@@ -427,22 +434,22 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
 
   /* We add this new entry last in the list. */
 
-  easy->next = NULL; /* end of the line */
+  data->next = NULL; /* end of the line */
   if(multi->easyp) {
     struct SessionHandle *last = multi->easylp;
-    last->next = easy;
+    last->next = data;
-    easy->prev = last;
+    data->prev = last;
-    multi->easylp = easy; /* the new last node */
+    multi->easylp = data; /* the new last node */
   }
   else {
     /* first node, make both prev and next be NULL! */
-    easy->next = NULL;
+    data->next = NULL;
-    easy->prev = NULL;
+    data->prev = NULL;
-    multi->easylp = multi->easyp = easy; /* both first and last */
+    multi->easylp = multi->easyp = data; /* both first and last */
   }
 
   /* make the SessionHandle refer back to this multi handle */
-  Curl_easy_addmulti(easy_handle, multi_handle);
+  Curl_easy_addmulti(data, multi_handle);
 
   /* Set the timeout for this handle to expire really soon so that it will
      be taken care of even when this handle is added in the midst of operation
@@ -450,7 +457,7 @@ CURLMcode curl_multi_add_handle(CURLM *multi_handle,
      sockets that time-out or have actions will be dealt with. Since this
      handle has no action yet, we make sure it times out to get things to
      happen. */
-  Curl_expire(easy, 1);
+  Curl_expire(data, 1);
 
   /* increase the node-counter */
   multi->num_easy++;
@@ -1811,7 +1818,8 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
 
     if(multi->closure_handle) {
       multi->closure_handle->dns.hostcache = multi->hostcache;
-      Curl_hostcache_clean(multi->closure_handle);
+      Curl_hostcache_clean(multi->closure_handle,
+                           multi->closure_handle->dns.hostcache);
 
       Curl_close(multi->closure_handle);
       multi->closure_handle = NULL;
@@ -1833,7 +1841,7 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
       nexteasy=easy->next;
       if(easy->dns.hostcachetype == HCACHE_MULTI) {
         /* clear out the usage of the shared DNS cache */
-        Curl_hostcache_clean(easy);
+        Curl_hostcache_clean(easy, easy->dns.hostcache);
         easy->dns.hostcache = NULL;
         easy->dns.hostcachetype = HCACHE_NONE;
       }

tests/data/Makefile.am

@@ -113,7 +113,7 @@ test1400 test1401 test1402 test1403 test1404 test1405 test1406 test1407 \
 test1408 test1409 test1410          test1412 test1413 test1414 \
 \
 test1500 test1501 test1502 test1503 test1504 test1505 test1506 test1507 \
-test1508 test1509 test1510 test1511 \
+test1508 test1509 test1510 test1511 test1512 \
 \
 test1900 test1901 test1902 test1903 \
 \

tests/data/test1512

@@ -0,0 +1,80 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+GLOBAL DNS CACHE
+</keywords>
+</info>
+
+# Server-side
+<reply>
+<data1>
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Content-Length: 47
+
+file contents should appear once for each file
+</data1>
+<data2>
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Content-Length: 47
+
+file contents should appear once for each file
+</data2>
+<data3>
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Content-Length: 47
+
+file contents should appear once for each file
+</data3>
+<data4>
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Content-Length: 47
+
+file contents should appear once for each file
+</data4>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+<tool>
+lib1512
+</tool>
+ <name>
+GLOBAL CACHE test over two easy performs
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/path/1512 %HOSTIP %HTTPPORT
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+GET /path/15120001 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+GET /path/15120002 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+</protocol>
+<strip>
+^Host:.*
+</strip>
+<stripfile>
+$_ = '' if (($_ !~ /left intact/) && ($_ !~ /Closing connection/))
+</stripfile>
+</verify>
+</testcase>

tests/libtest/Makefile.inc

@@ -21,7 +21,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect                \
  lib571 lib572 lib573 lib574 lib575 lib576        lib578 lib579 lib582   \
  lib583 lib585 lib586 lib587        lib590 lib591 lib597 lib598 lib599   \
  lib1500 lib1501 lib1502 lib1503 lib1504 lib1505 lib1506 lib1507 lib1508 \
- lib1509 lib1510 lib1511 \
+ lib1509 lib1510 lib1511 lib1512 \
  lib1900 \
  lib2033
 
@@ -339,6 +339,10 @@ lib1511_SOURCES = lib1511.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1511_LDADD = $(TESTUTIL_LIBS)
 lib1511_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1511
 
+lib1512_SOURCES = lib1512.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1512_LDADD = $(TESTUTIL_LIBS)
+lib1512_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1512
+
 lib1900_SOURCES = lib1900.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1900_LDADD = $(TESTUTIL_LIBS)
 lib1900_CPPFLAGS = $(AM_CPPFLAGS)

tests/libtest/lib1512.c

@@ -0,0 +1,89 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2013, Linus Nielsen Feltzing <linus@haxx.se>
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+/*
+ * Use global DNS cache (while deprecated it should still work), populate it
+ * with CURLOPT_RESOLVE in the first request and then make sure a subsequent
+ * easy transfer finds and uses the populated stuff.
+ */
+
+#include "test.h"
+
+#include "memdebug.h"
+
+#define NUM_HANDLES 2
+
+int test(char *URL)
+{
+  CURLcode res;
+  CURL *curl[NUM_HANDLES] = {NULL, NULL};
+  char *port = libtest_arg3;
+  char *address = libtest_arg2;
+  char dnsentry[256];
+  struct curl_slist *slist = NULL;
+  int i;
+  char target_url[256];
+  (void)URL; /* URL is setup in the code */
+
+  if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK) {
+    fprintf(stderr, "curl_global_init() failed\n");
+    return TEST_ERR_MAJOR_BAD;
+  }
+
+  sprintf(dnsentry, "server.example.curl:%s:%s", port, address);
+  printf("%s\n", dnsentry);
+  slist = curl_slist_append(slist, dnsentry);
+
+  /* get NUM_HANDLES easy handles */
+  for(i=0; i < NUM_HANDLES; i++) {
+    /* get an easy handle */
+    easy_init(curl[i]);
+    /* specify target */
+    sprintf(target_url, "http://server.example.curl:%s/path/1512%04i",
+            port, i + 1);
+    target_url[sizeof(target_url) - 1] = '\0';
+    easy_setopt(curl[i], CURLOPT_URL, target_url);
+    /* go verbose */
+    easy_setopt(curl[i], CURLOPT_VERBOSE, 1L);
+    /* include headers */
+    easy_setopt(curl[i], CURLOPT_HEADER, 1L);
+
+    easy_setopt(curl[i], CURLOPT_DNS_USE_GLOBAL_CACHE, 1L);
+  }
+
+  /* make the first one populate the GLOBAL cache */
+  easy_setopt(curl[0], CURLOPT_RESOLVE, slist);
+
+  /* run NUM_HANDLES transfers */
+  for(i=0; (i < NUM_HANDLES) && !res; i++)
+    res = curl_easy_perform(curl[i]);
+
+test_cleanup:
+
+  curl_easy_cleanup(curl[0]);
+  curl_easy_cleanup(curl[1]);
+  curl_slist_free_all(slist);
+  curl_global_cleanup();
+
+  return (int)res;
+}
+