diff --git a/ChangeLog b/ChangeLog
index ad3da2f08c..d6e14d7735 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Tue Jan 13 21:38:07 2009  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/socket.c (rb_getaddrinfo): use getaddrinfo with GVL if
+	  getaddrinfo.c/getnameinfo.c is used.  They are not thread safe
+	  because gethostbyname/gethostbyaddr is used.
+	  (rb_getnameinfo): ditto.
+
+	* extconf.rb: define GETADDRINFO_EMU if getaddrinfo.c/getnameinfo.c is
+	  used.
+
 Tue Jan 13 21:28:14 2009  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
 
 	* object.c (rb_obj_not_match): rdoc.
diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index 06011d61a8..443dd7d21e 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -251,6 +251,7 @@ unless getaddr_info_ok and have_func("getnameinfo", headers) and have_func("geta
   $CPPFLAGS="-I. "+$CPPFLAGS
   $objs += ["getaddrinfo.#{$OBJEXT}"]
   $objs += ["getnameinfo.#{$OBJEXT}"]
+  $defs << "-DGETADDRINFO_EMU"
   have_func("inet_ntop") or have_func("inet_ntoa")
   have_func("inet_pton") or have_func("inet_aton")
   have_func("getservbyport")
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index f608e6e434..cd6acd4647 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -238,6 +238,7 @@ ruby_getnameinfo__aix(const struct sockaddr *sa, size_t salen,
 #define close closesocket
 #endif
 
+#ifndef GETADDRINFO_EMU
 struct getaddrinfo_arg
 {
     const char *node;
@@ -253,12 +254,16 @@ nogvl_getaddrinfo(void *arg)
     return getaddrinfo(ptr->node, ptr->service,
                        ptr->hints, ptr->res);
 }
+#endif
 
 static int
 rb_getaddrinfo(const char *node, const char *service,
                const struct addrinfo *hints,
                struct addrinfo **res)
 {
+#ifdef GETADDRINFO_EMU
+    return getaddrinfo(node, service, hints, res);
+#else
     struct getaddrinfo_arg arg;
     int ret;
     arg.node = node;
@@ -267,8 +272,10 @@ rb_getaddrinfo(const char *node, const char *service,
     arg.res = res;
     ret = BLOCKING_REGION(nogvl_getaddrinfo, &arg);
     return ret;
+#endif
 }
 
+#ifndef GETADDRINFO_EMU
 struct getnameinfo_arg
 {
     const struct sockaddr *sa;
@@ -289,12 +296,16 @@ nogvl_getnameinfo(void *arg)
                        ptr->serv, ptr->servlen,
                        ptr->flags);
 }
+#endif
 
 static int
 rb_getnameinfo(const struct sockaddr *sa, socklen_t salen,
            char *host, size_t hostlen,
            char *serv, size_t servlen, int flags)
 {
+#ifdef GETADDRINFO_EMU
+    return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
+#else
     struct getnameinfo_arg arg;
     int ret;
     arg.sa = sa;
@@ -306,6 +317,7 @@ rb_getnameinfo(const struct sockaddr *sa, socklen_t salen,
     arg.flags = flags;
     ret = BLOCKING_REGION(nogvl_getnameinfo, &arg);
     return ret;
+#endif
 }
 
 static int