Fix previous patch to match its commit message

ChangeLog

 2014-12-29  Paul Eggert  <eggert@cs.ucla.edu>
 
 	system-name's returned value can vary
+	Also, the system-name variable is now obsolete.
 	Fixes Bug#19438.
 	* doc/lispref/os.texi (System Environment):
 	* etc/NEWS: Document this.
@@ -8,6 +9,7 @@
 	(Displaying the current file name in the titlebar):
 	* lisp/desktop.el (desktop-save-frameset):
 	* lisp/dnd.el (dnd-get-local-file-uri):
+	* lisp/gnus/message.el (message-make-fqdn):
 	* lisp/gnus/nnvirtual.el (nnvirtual-retrieve-headers)
 	(nnvirtual-update-xref-header):
 	* lisp/nxml/rng-uri.el (rng-uri-file-name-1):
@@ -16,14 +18,18 @@
 	* src/xrdb.c (get_environ_db):
 	* src/xterm.c (same_x_server):
 	* src/xterm.c (x_term_init):
-	Prefer (system-name) to system-name.
+	Prefer (system-name) to system-name, and avoid naming
+	locals 'system-name'.
 	* doc/misc/smtpmail.texi (Server workarounds): Fix grammar.
+	* lisp/startup.el (system-name): Now an obsolete variable.
 	* src/editfns.c (cached_system_name): New static var.
 	(init_and_cache_system_name): New function.
 	(init_editfns, Fsystem_name): Use it.
 	(syms_of_editfns): Initialize it and Vsystem_name to the same value.
-	* src/sysdep.c (init_system_name): Don't create a new string if
-	the current value is already correct.
+	* src/sysdep.c [HAVE_SOCKETS]: Don't include <sys/socket.h>, <netdb.h>.
+	(h_errno) [TRY_AGAIN && !HAVE_H_ERRNO]: Remove decl.
+	(init_system_name) [HAVE_SOCKETS]: Don't canonicalize the name.
+	Don't create a new string if the current value is already correct.
 
 2014-12-28  Paul Eggert  <eggert@cs.ucla.edu>
 

doc/lispref/os.texi

@@ -917,18 +917,6 @@ This function returns the name of the machine you are running on, as a
 string.
 @end defun
 
-  The symbol @code{system-name} is a variable as well as a function.  In
-fact, the function normally returns whatever value the variable
-@code{system-name} currently holds.  Thus, you can set the variable
-@code{system-name} in case Emacs is confused about the name of your
-system.  If you do not set the variable, the function updates
-the variable to the current system name; this behavior can be useful
-if your Emacs process has changed systems or if the system has changed
-names.
-
-The @code{system-name} variable is also useful for constructing frame titles
-(@pxref{Frame Titles}).
-
 @c FIXME seems like this section is not the best place for this option?
 @defopt mail-host-address
 If this variable is non-@code{nil}, it is used instead of

etc/NEWS

@@ -542,7 +542,9 @@ optional repeat-count argument.
 ** Function `sort' can deal with vectors.
 
 ** Function `system-name' now returns an updated value if the current
-system's name has changed, or if the Emacs process has changed systems.
+system's name has changed or if the Emacs process has changed systems,
+and to avoid long waits it no longer consults DNS to canonicalize the
+name.  The variable `system-name' is now obsolete.
 
 ---
 ** New utilities in subr-x.el:

lisp/dnd.el

@@ -122,17 +122,17 @@ Return nil if URI is not a local file."
 
   ;; The hostname may be our hostname, in that case, convert to a local
   ;; file.  Otherwise return nil.  TODO:  How about an IP-address as hostname?
-  (let ((system-name (system-name)))
+  (let ((sysname (system-name)))
     (let ((hostname (when (string-match "^file://\\([^/]*\\)" uri)
 		      (downcase (match-string 1 uri))))
-	  (system-name-no-dot
-	   (downcase (if (string-match "^[^\\.]+" system-name)
-			 (match-string 0 system-name)
-		       system-name))))
+	  (sysname-no-dot
+	   (downcase (if (string-match "^[^\\.]+" sysname)
+			 (match-string 0 sysname)
+		       sysname))))
       (when (and hostname
 		 (or (string-equal "localhost" hostname)
-		     (string-equal (downcase system-name) hostname)
-		     (string-equal system-name-no-dot hostname)))
+		     (string-equal (downcase sysname) hostname)
+		     (string-equal sysname-no-dot hostname)))
 	(concat "file://" (substring uri (+ 7 (length hostname))))))))
 
 (defsubst dnd-unescape-uri (uri)

lisp/gnus/message.el

@@ -5849,7 +5849,7 @@ give as trustworthy answer as possible."
 
 (defun message-make-fqdn ()
   "Return user's fully qualified domain name."
-  (let* ((system-name (system-name))
+  (let* ((sysname (system-name))
 	 (user-mail (message-user-mail-address))
 	 (user-domain
 	  (if (and user-mail
@@ -5863,10 +5863,10 @@ give as trustworthy answer as possible."
 	   (not (string-match message-bogus-system-names message-user-fqdn)))
       ;; `message-user-fqdn' seems to be valid
       message-user-fqdn)
-     ((and (string-match message-valid-fqdn-regexp system-name)
-	   (not (string-match message-bogus-system-names system-name)))
+     ((and (string-match message-valid-fqdn-regexp sysname)
+	   (not (string-match message-bogus-system-names sysname)))
       ;; `system-name' returned the right result.
-      system-name)
+      sysname)
      ;; Try `mail-host-address'.
      ((and (boundp 'mail-host-address)
 	   (stringp mail-host-address)
@@ -5881,7 +5881,7 @@ give as trustworthy answer as possible."
       user-domain)
      ;; Default to this bogus thing.
      (t
-      (concat system-name
+      (concat sysname
 	      ".i-did-not-set--mail-host-address--so-tickle-me")))))
 
 (defun message-make-domain ()

lisp/gnus/nnvirtual.el

@@ -99,7 +99,7 @@ component group will show up when you enter the virtual group.")
 	(let ((vbuf (nnheader-set-temp-buffer
 		     (get-buffer-create " *virtual headers*")))
 	      (carticles (nnvirtual-partition-sequence articles))
-	      (system-name (system-name))
+	      (sysname (system-name))
 	      cgroup carticle article result prefix)
 	  (while carticles
 	    (setq cgroup (caar carticles))
@@ -151,7 +151,7 @@ component group will show up when you enter the virtual group.")
 		  ;; and clean up the xrefs.
 		  (princ article nntp-server-buffer)
 		  (nnvirtual-update-xref-header cgroup carticle
-						prefix (system-name))
+						prefix sysname)
 		  (forward-line 1))
 		)
 
@@ -378,7 +378,7 @@ component group will show up when you enter the virtual group.")
       (mapc 'nnheader-insert-nov headers))))
 
 
-(defun nnvirtual-update-xref-header (group article prefix system-name)
+(defun nnvirtual-update-xref-header (group article prefix sysname)
   "Edit current NOV header in current buffer to have an xref to the component group, and also server prefix any existing xref lines."
   ;; Move to beginning of Xref field, creating a slot if needed.
   (beginning-of-line)
@@ -393,7 +393,7 @@ component group will show up when you enter the virtual group.")
     (forward-char -1)
     (delete-char 1))
 
-  (insert "Xref: " (system-name) " " group ":")
+  (insert "Xref: " sysname " " group ":")
   (princ article (current-buffer))
   (insert " ")
 

lisp/startup.el

@@ -358,6 +358,8 @@ this variable usefully is to set it while building and dumping Emacs."
   :set (lambda (_variable _value)
 	  (error "Customizing `site-run-file' does not work")))
 
+(make-obsolete-variable 'system-name "use (system-name) instead" "25.1")
+
 (defcustom mail-host-address nil
   "Name of this machine, for purposes of naming users.
 If non-nil, Emacs uses this instead of `system-name' when constructing

src/sysdep.c

@@ -1406,17 +1406,6 @@ setup_pty (int fd)
 }
 #endif /* HAVE_PTYS */
 
-#ifdef HAVE_SOCKETS
-#include <sys/socket.h>
-#include <netdb.h>
-#endif /* HAVE_SOCKETS */
-
-#ifdef TRY_AGAIN
-#ifndef HAVE_H_ERRNO
-extern int h_errno;
-#endif
-#endif /* TRY_AGAIN */
-
 void
 init_system_name (void)
 {
@@ -1447,101 +1436,6 @@ init_system_name (void)
       hostname = hostname_alloc = xpalloc (hostname_alloc, &hostname_size, 1,
 					   min (PTRDIFF_MAX, SIZE_MAX), 1);
     }
-#ifdef HAVE_SOCKETS
-  /* Turn the hostname into the official, fully-qualified hostname.
-     Don't do this if we're going to dump; this can confuse system
-     libraries on some machines and make the dumped emacs core dump. */
-#ifndef CANNOT_DUMP
-  if (initialized)
-#endif /* not CANNOT_DUMP */
-    if (! strchr (hostname, '.'))
-      {
-	int count;
-#ifdef HAVE_GETADDRINFO
-        struct addrinfo *res;
-        struct addrinfo hints;
-        int ret;
-
-        memset (&hints, 0, sizeof (hints));
-        hints.ai_socktype = SOCK_STREAM;
-        hints.ai_flags = AI_CANONNAME;
-
-	for (count = 0;; count++)
-	  {
-            if ((ret = getaddrinfo (hostname, NULL, &hints, &res)) == 0
-                || ret != EAI_AGAIN)
-              break;
-
-            if (count >= 5)
-	      break;
-	    Fsleep_for (make_number (1), Qnil);
-	  }
-
-        if (ret == 0)
-          {
-            struct addrinfo *it = res;
-            while (it)
-              {
-                char *fqdn = it->ai_canonname;
-                if (fqdn && strchr (fqdn, '.')
-                    && strcmp (fqdn, "localhost.localdomain") != 0)
-                  break;
-                it = it->ai_next;
-              }
-            if (it)
-              {
-		ptrdiff_t len = strlen (it->ai_canonname);
-		if (hostname_size <= len)
-		  {
-		    hostname_size = len + 1;
-		    hostname = hostname_alloc = xrealloc (hostname_alloc,
-							  hostname_size);
-		  }
-                strcpy (hostname, it->ai_canonname);
-              }
-            freeaddrinfo (res);
-          }
-#else /* !HAVE_GETADDRINFO */
-        struct hostent *hp;
-	for (count = 0;; count++)
-	  {
-
-#ifdef TRY_AGAIN
-	    h_errno = 0;
-#endif
-	    hp = gethostbyname (hostname);
-#ifdef TRY_AGAIN
-	    if (! (hp == 0 && h_errno == TRY_AGAIN))
-#endif
-
-	      break;
-
-	    if (count >= 5)
-	      break;
-	    Fsleep_for (make_number (1), Qnil);
-	  }
-
-	if (hp)
-	  {
-	    char *fqdn = (char *) hp->h_name;
-
-	    if (!strchr (fqdn, '.'))
-	      {
-		/* We still don't have a fully qualified domain name.
-		   Try to find one in the list of alternate names */
-		char **alias = hp->h_aliases;
-		while (*alias
-		       && (!strchr (*alias, '.')
-			   || !strcmp (*alias, "localhost.localdomain")))
-		  alias++;
-		if (*alias)
-		  fqdn = *alias;
-	      }
-	    hostname = fqdn;
-	  }
-#endif /* !HAVE_GETADDRINFO */
-      }
-#endif /* HAVE_SOCKETS */
 #endif /* HAVE_GETHOSTNAME */
   char *p;
   for (p = hostname; *p; p++)