xauth/xauth-tolerant-hostname-changes.diff

Index: xauth-1.0.8/gethost.c
===================================================================
--- xauth-1.0.8.orig/gethost.c
+++ xauth-1.0.8/gethost.c
@@ -156,7 +156,8 @@ struct addrlist *get_address_info (
     int family,
     const char *fulldpyname,
     int prefix,
-    char *host)
+    char *host,
+    char *localhostname)
 {
     struct addrlist *retval = NULL;
     int len = 0;
@@ -183,7 +184,7 @@ struct addrlist *get_address_info (
 	if (prefix == 0 && (strncmp (fulldpyname, "unix:", 5) == 0 ||
 			    fulldpyname[0] == ':')) {
 
-	    if (!get_local_hostname (buf, sizeof buf)) {
+	    if (!get_local_hostname (buf, sizeof buf, localhostname)) {
 		len = 0;
 	    } else {
 		src = buf;
@@ -233,7 +234,7 @@ struct addrlist *get_address_info (
 		src = &(sin->sin_addr);
                 if (*(const in_addr_t *) src == htonl(INADDR_LOOPBACK)) {
                     family = FamilyLocal;
-                    if (get_local_hostname (buf, sizeof buf)) {
+                    if (get_local_hostname (buf, sizeof buf, localhostname)) {
                         src = buf;
                         len = strlen (buf);
                     } else
@@ -248,7 +249,7 @@ struct addrlist *get_address_info (
                 if (!IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)src)) {
                     if (IN6_IS_ADDR_LOOPBACK((const struct in6_addr *)src)) {
                         family = FamilyLocal;
-                        if (get_local_hostname (buf, sizeof buf)) {
+                        if (get_local_hostname (buf, sizeof buf, localhostname)) {
                             src = buf;
                             len = strlen (buf);
                         } else
@@ -303,7 +304,7 @@ struct addrlist *get_address_info (
 	src = (char *) &hostinetaddr;
         if (*(const in_addr_t *) src == htonl(INADDR_LOOPBACK)) {
             family = FamilyLocal;
-            if (get_local_hostname (buf, sizeof buf)) {
+            if (get_local_hostname (buf, sizeof buf, localhostname)) {
                 src = buf;
                 len = strlen (buf);
             } else {
Index: xauth-1.0.8/parsedpy.c
===================================================================
--- xauth-1.0.8.orig/parsedpy.c
+++ xauth-1.0.8/parsedpy.c
@@ -70,20 +70,23 @@ copystring (const char *src, int len)
 
 
 char *
-get_local_hostname (char *buf, int maxlen)
+get_local_hostname (char *buf, int maxlen, char *localhostname)
 {
     buf[0] = '\0';
+    if (localhostname)
+       strncpy(buf, localhostname, maxlen);
+    else
     (void) XmuGetHostname (buf, maxlen);
     return (buf[0] ? buf : NULL);
 }
 
 #ifndef UNIXCONN
 static char *
-copyhostname (void)
+copyhostname (char *localhostname)
 {
     char buf[256];
 
-    return (get_local_hostname (buf, sizeof buf) ?
+    return (get_local_hostname (buf, sizeof buf, localhostname) ?
 	    copystring (buf, strlen (buf)) : NULL);
 }
 #endif
@@ -93,6 +96,7 @@ copyhostname (void)
  */
 Bool
 parse_displayname (const char *displayname,
+		   char *localhostname,
 		   int *familyp,	/* return */
 		   char **hostp,	/* return */
 		   int *dpynump,	/* return */
@@ -134,7 +138,7 @@ parse_displayname (const char *displayna
 	    host = copystring ("0", 1);
 	    family = FamilyDECnet;
 	} else {
-	    host = copyhostname ();
+	    host = copyhostname (localhostname);
 	    family = FamilyInternet;
 	}
 #endif
Index: xauth-1.0.8/process.c
===================================================================
--- xauth-1.0.8.orig/process.c
+++ xauth-1.0.8/process.c
@@ -470,7 +470,7 @@ read_auth_entries(FILE *fp, Bool numeric
 }
 
 static Bool
-get_displayname_auth(const char *displayname, AuthList **authl)
+get_displayname_auth(const char *displayname, AuthList **authl, char *localhostname)
 {
     int family;
     char *host = NULL, *rest = NULL;
@@ -490,11 +490,13 @@ get_displayname_auth(const char *display
       prelen = (cp - displayname);
 
     if (!parse_displayname (displayname + ((prelen > 0) ? prelen + 1 : 0),
+			    localhostname,
 			    &family, &host, &dpynum, &scrnum, &rest)) {
 	return False;
     }
 
-    addrlist_head = get_address_info(family, displayname, prelen, host);
+    addrlist_head = get_address_info(family, displayname, prelen, host,
+				     localhostname);
     if (addrlist_head) {
 	char buf[40];			/* want to hold largest display num */
 	unsigned short dpylen;
@@ -1240,13 +1242,18 @@ iterdpy (const char *inputfilename, int
     Xauth *tmp_auth;
     AuthList *proto_head, *proto;
     AuthList *l, *next;
-
+    /*
+     * get saved local address from environment in case the host
+     * name has changed after the credential was added.
+     */
+    char *xlocalhostname = getenv("XAUTHLOCALHOSTNAME");
+    
     /*
      * iterate
      */
     for (i = start; i < argc; i++) {
 	const char *displayname = argv[i];
-	if (!get_displayname_auth (displayname, &proto_head)) {
+	if (!get_displayname_auth (displayname, &proto_head, xlocalhostname)) {
 	    prefix (inputfilename, lineno);
 	    baddisplayname (displayname, argv[0]);
 	    errors++;
@@ -1601,7 +1608,7 @@ do_add(const char *inputfilename, int li
 	}
     }
 
-    if (!get_displayname_auth (dpyname, &list)) {
+    if (!get_displayname_auth (dpyname, &list, NULL)) {
 	prefix (inputfilename, lineno);
 	baddisplayname (dpyname, argv[0]);
 	free (key);
Index: xauth-1.0.8/xauth.h
===================================================================
--- xauth-1.0.8.orig/xauth.h
+++ xauth-1.0.8/xauth.h
@@ -48,10 +48,10 @@ struct addrlist {
 };
 
 extern const char *get_hostname ( Xauth *auth );
-extern struct addrlist *get_address_info ( int family, const char *fulldpyname, int prefix, char *host);
+extern struct addrlist *get_address_info ( int family, const char *fulldpyname, int prefix, char *host, char *localhostname);
 extern char *copystring ( const char *src, int len );
-extern char *get_local_hostname ( char *buf, int maxlen );
-extern Bool parse_displayname ( const char *displayname, int *familyp, char **hostp, int *dpynump, int *scrnump, char **restp );
+extern char *get_local_hostname ( char *buf, int maxlen, char *localhostname );
+extern Bool parse_displayname ( const char *displayname, char *localhostname, int *familyp, char **hostp, int *dpynump, int *scrnump, char **restp );
 extern int auth_initialize ( const char *authfilename );
 extern int auth_finalize ( void );
 extern int process_command ( const char *inputfilename, int lineno, int argc, const char **argv );