url: use goto in create_conn() for exception handling

Instead of remembering before each "return" statement which temporary
allocations, if any, need to be freed, take care to set pointers to
NULL when no longer needed and use a goto to a common block to exit
the function and free all temporaries.

No functional change intended.  Currently the only temporary buffer in
this function is "proxy" which is already correctly freed when
appropriate, but there will be more soon.

lib/url.c

@@ -5063,8 +5063,10 @@ static CURLcode create_conn(struct SessionHandle *data,
    * Check input data
    *************************************************************/
 
-  if(!data->change.url)
-    return CURLE_URL_MALFORMAT;
+  if(!data->change.url) {
+    result = CURLE_URL_MALFORMAT;
+    goto out;
+  }
 
   /* First, split up the current URL in parts so that we can use the
      parts for checking against the already present connections. In order
@@ -5072,8 +5074,10 @@ static CURLcode create_conn(struct SessionHandle *data,
      connection data struct and fill in for comparison purposes. */
   conn = allocate_conn(data);
 
-  if(!conn)
-    return CURLE_OUT_OF_MEMORY;
+  if(!conn) {
+    result = CURLE_OUT_OF_MEMORY;
+    goto out;
+  }
 
   /* We must set the return variable as soon as possible, so that our
      parent can cleanup any possible allocs we may have done before
@@ -5103,15 +5107,18 @@ static CURLcode create_conn(struct SessionHandle *data,
   data->state.path = NULL;
 
   data->state.pathbuffer = malloc(urllen+2);
-  if(NULL == data->state.pathbuffer)
-    return CURLE_OUT_OF_MEMORY; /* really bad error */
+  if(NULL == data->state.pathbuffer) {
+    result = CURLE_OUT_OF_MEMORY; /* really bad error */
+    goto out;
+  }
   data->state.path = data->state.pathbuffer;
 
   conn->host.rawalloc = malloc(urllen+2);
   if(NULL == conn->host.rawalloc) {
     Curl_safefree(data->state.pathbuffer);
     data->state.path = NULL;
-    return CURLE_OUT_OF_MEMORY;
+    result = CURLE_OUT_OF_MEMORY;
+    goto out;
   }
 
   conn->host.name = conn->host.rawalloc;
@@ -5120,7 +5127,7 @@ static CURLcode create_conn(struct SessionHandle *data,
   result = parseurlandfillconn(data, conn, &prot_missing, user, passwd,
                                options);
   if(result != CURLE_OK)
-    return result;
+    goto out;
 
   /*************************************************************
    * No protocol part in URL was used, add it!
@@ -5134,8 +5141,8 @@ static CURLcode create_conn(struct SessionHandle *data,
     reurl = aprintf("%s://%s", conn->handler->scheme, data->change.url);
 
     if(!reurl) {
-      Curl_safefree(proxy);
-      return CURLE_OUT_OF_MEMORY;
+      result = CURLE_OUT_OF_MEMORY;
+      goto out;
     }
 
     if(data->change.url_alloc) {
@@ -5172,7 +5179,7 @@ static CURLcode create_conn(struct SessionHandle *data,
   if(conn->bits.proxy_user_passwd) {
     result = parse_proxy_auth(data, conn);
     if(result != CURLE_OK)
-      return result;
+      goto out;
   }
 
   /*************************************************************
@@ -5183,7 +5190,8 @@ static CURLcode create_conn(struct SessionHandle *data,
     /* if global proxy is set, this is it */
     if(NULL == proxy) {
       failf(data, "memory shortage");
-      return CURLE_OUT_OF_MEMORY;
+      result = CURLE_OUT_OF_MEMORY;
+      goto out;
     }
   }
 
@@ -5211,16 +5219,17 @@ static CURLcode create_conn(struct SessionHandle *data,
   if(proxy) {
     result = parse_proxy(data, conn, proxy);
 
-    free(proxy); /* parse_proxy copies the proxy string */
+    Curl_safefree(proxy); /* parse_proxy copies the proxy string */
 
     if(result)
-      return result;
+      goto out;
 
     if((conn->proxytype == CURLPROXY_HTTP) ||
        (conn->proxytype == CURLPROXY_HTTP_1_0)) {
 #ifdef CURL_DISABLE_HTTP
       /* asking for a HTTP proxy is a bit funny when HTTP is disabled... */
-      return CURLE_UNSUPPORTED_PROTOCOL;
+      result = CURLE_UNSUPPORTED_PROTOCOL;
+      goto out;
 #else
       /* force this connection's protocol to become HTTP if not already
          compatible - if it isn't tunneling through */
@@ -5257,24 +5266,22 @@ static CURLcode create_conn(struct SessionHandle *data,
    *************************************************************/
   result = parse_remote_port(data, conn);
   if(result != CURLE_OK)
-    return result;
+    goto out;
 
   /* Check for overridden login details and set them accordingly so they
      they are known when protocol->setup_connection is called! */
   override_login(data, conn, user, passwd, options);
   result = set_login(conn, user, passwd, options);
   if(result != CURLE_OK)
-    return result;
+    goto out;
 
   /*************************************************************
    * Setup internals depending on protocol. Needs to be done after
    * we figured out what/if proxy to use.
    *************************************************************/
   result = setup_connection_internals(conn);
-  if(result != CURLE_OK) {
-    Curl_safefree(proxy);
-    return result;
-  }
+  if(result != CURLE_OK)
+    goto out;
 
   conn->recv[FIRSTSOCKET] = Curl_recv_plain;
   conn->send[FIRSTSOCKET] = Curl_send_plain;
@@ -5307,7 +5314,7 @@ static CURLcode create_conn(struct SessionHandle *data,
         DEBUGASSERT(conn->handler->done);
         /* we ignore the return code for the protocol-specific DONE */
         (void)conn->handler->done(conn, result, FALSE);
-        return result;
+        goto out;
       }
 
       Curl_setup_transfer(conn, -1, -1, FALSE, NULL, /* no download */
@@ -5317,7 +5324,7 @@ static CURLcode create_conn(struct SessionHandle *data,
     /* since we skip do_init() */
     do_init(conn);
 
-    return result;
+    goto out;
   }
 #endif
 
@@ -5342,8 +5349,10 @@ static CURLcode create_conn(struct SessionHandle *data,
   data->set.ssl.password = data->set.str[STRING_TLSAUTH_PASSWORD];
 #endif
 
-  if(!Curl_clone_ssl_config(&data->set.ssl, &conn->ssl_config))
-    return CURLE_OUT_OF_MEMORY;
+  if(!Curl_clone_ssl_config(&data->set.ssl, &conn->ssl_config)) {
+    result = CURLE_OUT_OF_MEMORY;
+    goto out;
+  }
 
   /*************************************************************
    * Check the current list of connections to see if we can
@@ -5446,7 +5455,8 @@ static CURLcode create_conn(struct SessionHandle *data,
       conn_free(conn);
       *in_connect = NULL;
 
-      return CURLE_NO_CONNECTION_AVAILABLE;
+      result = CURLE_NO_CONNECTION_AVAILABLE;
+      goto out;
     }
     else {
       /*
@@ -5468,7 +5478,7 @@ static CURLcode create_conn(struct SessionHandle *data,
    */
   result = setup_range(data);
   if(result)
-    return result;
+    goto out;
 
   /* Continue connectdata initialization here. */
 
@@ -5486,6 +5496,9 @@ static CURLcode create_conn(struct SessionHandle *data,
    *************************************************************/
   result = resolve_server(data, conn, async);
 
+  out:
+
+  Curl_safefree(proxy);
   return result;
 }