Unverified Commit f73de32d authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

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
parent ebc05501

docs/DEPRECATE.md

+0 −20
Original line number Diff line number Diff line
@@ -5,26 +5,6 @@ email the curl-library mailing list as soon as possible and explain to us why 
this is a problem for you and how your use case can't be satisfied properly

using a work around.



## `CURLOPT_DNS_USE_GLOBAL_CACHE`



This option makes libcurl use a global non-thread-safe cache for DNS if

enabled. The option has been marked as "obsolete" in the header file and in

documentation for several years already.



There's proper and safe method alternative provided since many years: the

share API.



### State



In curl 7.62.0 setting this option to TRUE will not have any effect. The

global cache will not be enabled. The code still remains so it is easy to

revert if need be.



### Removal



Remove all global-cache related code from curl around April 2019 (might be

7.66.0).



## HTTP/0.9



Supporting this is non-obvious and might even come as a surprise to some

docs/libcurl/opts/CURLOPT_DNS_USE_GLOBAL_CACHE.3

+4 −2
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@@ -5,7 +5,7 @@ 
.\" *                            | (__| |_| |  _ <| |___

.\" *                             \___|\___/|_| \_\_____|

.\" *

.\" * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.

.\" * Copyright (C) 1998 - 2019, 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
@@ -29,6 +29,8 @@ CURLOPT_DNS_USE_GLOBAL_CACHE \- enable/disable global DNS cache 
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_USE_GLOBAL_CACHE,

                          long enable);

.SH DESCRIPTION

Has no function since 7.62.0. Do note use!



Pass a long. If the \fIenable\fP value is 1, it tells curl to use a global DNS

cache that will survive between easy handle creations and deletions. This is

not thread-safe and this will use a global variable.
@@ -53,7 +55,7 @@ if(curl) { 
}

.fi

.SH AVAILABILITY

Subject for removal in the future. Do not use!

Deprecated since 7.62.0. Has no function.

.SH RETURN VALUE

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

.SH "SEE ALSO"

lib/easy.c

+0 −1
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@@ -265,7 +265,6 @@ void curl_global_cleanup(void) 
  if(--initialized)

    return;



  Curl_global_host_cache_dtor();

  Curl_ssl_cleanup();

  Curl_resolver_global_cleanup();

lib/hostip.c

+0 −34
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@@ -114,42 +114,8 @@ 
 * 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

 */

lib/multi.c

+1 −11
Original line number Diff line number Diff line
@@ -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;