Non-blocking connect() attempts may fail synchronously

net/base/host_resolver_proc.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/host_resolver_proc.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <ws2tcpip.h>
@@ skipping 139 matching lines @@
   //         enable ADDRCONFIG behavior
   //
   // Not only is AI_ADDRCONFIG unnecessary, but it can be harmful.  If the
   // computer is not connected to a network, AI_ADDRCONFIG causes getaddrinfo
   // to fail with WSANO_DATA (11004) for "localhost", probably because of the
   // following note on AI_ADDRCONFIG in the MSDN getaddrinfo page:
   //   The IPv4 or IPv6 loopback address is not considered a valid global
   //   address.
   // See http://crbug.com/5234.
   hints.ai_flags = 0;
-#elif defined(OS_MACOSX)
-  // We don't need to use AI_ADDRCONFIG on Mac OS X.  There are two evidences:
-  //
-  // 1. The getaddrinfo man page on Mac OS X documents only three flags:
-  // AI_CANONNAME, AI_NUMERICHOST, and AI_PASSIVE, and shows an example that
-  // sets hints.ai_flags to 0.
-  // 2. The <netdb.h> header lists only those three flags in the comment after
-  // the ai_flags field of struct addrinfo, and defines an AI_MASK macro as
-  // the bitwise-OR of those three flags with the comment "valid flags for
-  // addrinfo".
-  //
-  // But is it harmful to use AI_ADDRCONFIG?  Unfortunately I can't find a
-  // definitive answer by browsing the getaddrinfo source code in Darwin (in
-  // the Libinfo project).
-  //
-  // See http://crbug.com/12711.
-  hints.ai_flags = 0;
 #else
   hints.ai_flags = AI_ADDRCONFIG;
 #endif
 
   // Restrict result set to only this socket type to avoid duplicates.
   hints.ai_socktype = SOCK_STREAM;
 
   int err = getaddrinfo(host.c_str(), NULL, &hints, &ai);
 #if defined(OS_LINUX)
   net::DnsReloadTimer* dns_timer = Singleton<net::DnsReloadTimer>::get();
   // If we fail, re-initialise the resolver just in case there have been any
   // changes to /etc/resolv.conf and retry. See http://crbug.com/11380 for info.
   if (err && dns_timer->Expired()) {
     res_nclose(&_res);
     if (!res_ninit(&_res))
       err = getaddrinfo(host.c_str(), NULL, &hints, &ai);
   }
 #endif
 
   if (err)
     return ERR_NAME_NOT_RESOLVED;
 
   addrlist->Adopt(ai);
   return OK;
 }
 
 }  // namespace net