Hi

Emacs is ipv6 enable, great. But it doesn't loop over all addresses it
get back from getaddrinfo. This causes problem if your ipv6 tunnel is
done, but you still have ipv4 connectivity.

The patch below saves the first errno, and the retries all addresses
until it runs out of them.

Thanks,
Love


--- process.c.orig	Thu Jul  8 00:36:24 1999
+++ process.c	Sun Feb 27 16:03:33 2000
@@ -1,7 +1,18 @@
+/*
+ * Locally hacked process.c to add ipv6 support. -wsr
+ *
+ * The configure.in file should define "HAVE_GETADDRINFO" if it is found 
+ * in libc.
+ * 
+ */
+
 /* Asynchronous subprocess control for GNU Emacs.
    Copyright (C) 1985, 86, 87, 88, 93, 94, 95, 96, 1998
       Free Software Foundation, Inc.
 
+   ipv6 changes are
+   Copyright (C) 1999 Wolfgang S. Rupprecht
+
 This file is part of GNU Emacs.
 
 GNU Emacs is free software; you can redistribute it and/or modify
@@ -1806,15 +1817,22 @@
 {
   Lisp_Object proc;
   register int i;
+
+#ifndef HAVE_GETADDRINFO
   struct sockaddr_in address;
   struct servent *svc_info;
   struct hostent *host_info_ptr, host_info;
   char *(addr_list[2]);
   IN_ADDR numeric_addr;
-  int s, outch, inch;
-  char errstring[80];
-  int port;
   struct hostent host_info_fixed;
+  int port;
+#else /* HAVE_GETADDRINFO */
+  int saved_errno;
+  struct addrinfo hints, *res, *lres;
+  int ret;
+  char *portstring, portbuf [128];
+#endif /* HAVE_GETADDRINFO */
+  int s, outch, inch;
   struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
   int retry = 0;
   int count = specpdl_ptr - specpdl;
@@ -1827,6 +1845,22 @@
   GCPRO4 (name, buffer, host, service);
   CHECK_STRING (name, 0);
   CHECK_STRING (host, 0);
+
+#ifdef HAVE_GETADDRINFO
+  /*
+   * caution: service can either be a string or int.
+   * Convert to a C string for later use by getaddrinfo.
+   */
+  if (INTEGERP (service)) {
+      snprintf (portbuf, sizeof (portbuf), "%d", XINT (service));
+      portstring = portbuf;
+  }
+  else
+    {
+      CHECK_STRING (service, 0);
+      portstring = XSTRING (service)->data;
+    }
+#else /* HAVE_GETADDRINFO */
   if (INTEGERP (service))
     port = htons ((unsigned short) XINT (service));
   else
@@ -1837,6 +1871,8 @@
 	error ("Unknown service \"%s\"", XSTRING (service)->data);
       port = svc_info->s_port;
     }
+#endif /* HAVE_GETADDRINFO */
+
 
   /* Slow down polling to every ten seconds.
      Some kernels have a bug which causes retrying connect to fail
@@ -1846,6 +1882,84 @@
 #endif
 
 #ifndef TERM
+#ifdef HAVE_GETADDRINFO		       /* We have a modern OS. -wsr */
+  {
+      immediate_quit = 1;
+      QUIT;
+      memset(&hints, 0, sizeof(hints));
+      hints.ai_flags = AI_NUMERICHOST;
+      hints.ai_family = AF_UNSPEC;
+      hints.ai_socktype = SOCK_STREAM;
+      hints.ai_protocol = 0;
+      ret = getaddrinfo(XSTRING (host)->data, portstring, &hints, &res);
+      if (!ret) {	 /* numeric */
+	 freeaddrinfo(res);
+	 hints.ai_flags = AI_CANONNAME;
+      } else {	 /* non-numeric */
+	 hints.ai_flags = 0;
+      }
+      ret = getaddrinfo(XSTRING (host)->data, portstring, &hints, &res);
+      if (ret){
+	 error("%s/%s %s", XSTRING (host)->data, portstring,
+	       gai_strerror(ret));
+      }
+      immediate_quit = 0;
+  }
+
+  for (lres = res; lres ; lres = lres->ai_next){ /* address loop */
+      s = socket(lres->ai_family, lres->ai_socktype, lres->ai_protocol);
+      if (s < 0) 
+	 report_file_error ("error creating socket", Fcons (name, Qnil));
+
+      /* Kernel bugs (on Ultrix at least) cause lossage (not just EINTR)
+	when connect is interrupted.  So let's not let it get interrupted.
+	Note we do not turn off polling, because polling is only used
+	when not interrupt_input, and thus not normally used on the systems
+	which have this bug.  On systems which use polling, there's no way
+	to quit if polling is turned off.  */
+      if (interrupt_input)
+	 unrequest_sigio ();
+
+  loop:
+
+      immediate_quit = 1;
+      QUIT;
+
+      if (connect(s, lres->ai_addr, lres->ai_addrlen) == -1
+	 && errno != EISCONN)
+	 {
+	     saved_errno = errno;
+
+	     immediate_quit = 0;
+
+	     if (errno == EINTR)
+		 goto loop;
+	     if (errno == EADDRINUSE && retry < 20)
+		 {
+		     /* A delay here is needed on some FreeBSD systems,
+			and it is harmless, since this retrying takes time anyway
+			and should be infrequent.  */
+		     Fsleep_for (make_number (1), Qnil);
+		     retry++;
+		     goto loop;
+		 }
+
+	     close (s);
+
+	     if (lres == NULL) {
+		 
+		 if (interrupt_input)
+		     request_sigio ();
+		 
+		 errno = saved_errno;
+		 report_file_error ("connection failed",
+				    Fcons (host, Fcons (name, Qnil)));
+	     }
+	 }
+  } /* address loop */
+  freeaddrinfo(res);
+#else /* HAVE_GETADDRINFO */
+
   while (1)
     {
 #ifdef TRY_AGAIN
@@ -1936,6 +2050,7 @@
       report_file_error ("connection failed",
 			 Fcons (host, Fcons (name, Qnil)));
     }
+#endif /* HAVE_GETADDRINFO */
 
   immediate_quit = 0;