CURLOPT_DNS_USE_GLOBAL_CACHE: remove

Remove the code too. The functionality has been disabled in code since
7.62.0. Setting this option will from now on simply be ignored and have
no function.

Closes #3654

5 files changed, 2 insertions, 53 deletions

diff --git a/lib/easy.c b/lib/easy.c
index ae6176f25..39482469c 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -265,7 +265,6 @@ void curl_global_cleanup(void)
   if(--initialized)
     return;
 
-  Curl_global_host_cache_dtor();
   Curl_ssl_cleanup();
   Curl_resolver_global_cleanup();
 
diff --git a/lib/hostip.c b/lib/hostip.c
index 7909141c1..365d3c661 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -114,43 +114,9 @@
  * CURLRES_* defines based on the config*.h and curl_setup.h defines.
  */
 
-/* These two symbols are for the global DNS cache */
-static struct curl_hash hostname_cache;
-static int host_cache_initialized;
-
 static void freednsentry(void *freethis);
 
 /*
- * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
- * Global DNS cache is general badness. Do not use. This will be removed in
- * a future version. Use the share interface instead!
- *
- * Returns a struct curl_hash pointer on success, NULL on failure.
- */
-struct curl_hash *Curl_global_host_cache_init(void)
-{
-  int rc = 0;
-  if(!host_cache_initialized) {
-    rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str,
-                        Curl_str_key_compare, freednsentry);
-    if(!rc)
-      host_cache_initialized = 1;
-  }
-  return rc?NULL:&hostname_cache;
-}
-
-/*
- * Destroy and cleanup the global DNS cache
- */
-void Curl_global_host_cache_dtor(void)
-{
-  if(host_cache_initialized) {
-    Curl_hash_destroy(&hostname_cache);
-    host_cache_initialized = 0;
-  }
-}
-
-/*
  * Return # of addresses in a Curl_addrinfo struct
  */
 int Curl_num_addresses(const Curl_addrinfo *addr)
diff --git a/lib/multi.c b/lib/multi.c
index 500c24229..2ebc56255 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -402,19 +402,9 @@ CURLMcode curl_multi_add_handle(struct Curl_multi *multi,
   /* set the easy handle */
   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. */
-  else if(!data->dns.hostcache ||
+  if(!data->dns.hostcache ||
      (data->dns.hostcachetype == HCACHE_NONE)) {
     data->dns.hostcache = &multi->hostcache;
     data->dns.hostcachetype = HCACHE_MULTI;
diff --git a/lib/setopt.c b/lib/setopt.c
index b5f74a93d..6e596fa66 100644
--- a/lib/setopt.c
+++ b/lib/setopt.c
@@ -128,11 +128,7 @@ static CURLcode vsetopt(struct Curl_easy *data, CURLoption option,
     data->set.dns_cache_timeout = arg;
     break;
   case CURLOPT_DNS_USE_GLOBAL_CACHE:
-#if 0 /* deprecated */
-    /* remember we want this enabled */
-    arg = va_arg(param, long);
-    data->set.global_dns_cache = (0 != arg) ? TRUE : FALSE;
-#endif
+    /* deprecated */
     break;
   case CURLOPT_SSL_CIPHER_LIST:
     /* set a list of cipher we want to use in the SSL connection */
diff --git a/lib/urldata.h b/lib/urldata.h
index 6558112d3..22a8e6dda 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1691,7 +1691,6 @@ struct UserDefined {
   bit ftp_use_pret:1;   /* if PRET is to be used before PASV or not */
 
   bit no_signal:1;      /* do not use any signal/alarm handler */
-  bit global_dns_cache:1; /* subject for future removal */
   bit tcp_nodelay:1;    /* whether to enable TCP_NODELAY or not */
   bit ignorecl:1;       /* ignore content length */
   bit ftp_skip_ip:1;    /* skip the IP address the FTP server passes on to
@@ -1732,7 +1731,6 @@ struct Names {
   struct curl_hash *hostcache;
   enum {
     HCACHE_NONE,    /* not pointing to anything */
-    HCACHE_GLOBAL,  /* points to the (shrug) global one */
     HCACHE_MULTI,   /* points to a shared one in the multi handle */
     HCACHE_SHARED   /* points to a shared one in a shared object */
   } hostcachetype;