diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/client/helpdata.c rulesetcrash/client/helpdata.c
--- freeciv-1.11.12/client/helpdata.c	Sat Sep  2 03:58:34 2000
+++ rulesetcrash/client/helpdata.c	Fri Aug 10 13:47:54 2001
@@ -203,10 +203,6 @@
   
   filename = datafilename("helpdata.txt");
   if (filename == NULL) {
-    freelog(LOG_ERROR, "Could not find readable helpdata.txt in data path");
-    freelog(LOG_ERROR, "The data path may be set via"
-	                " the environment variable FREECIV_PATH");
-    freelog(LOG_ERROR, "Current data path is: \"%s\"", datafilename(NULL));
     freelog(LOG_ERROR, "Did not read help texts");
     return;
   }
diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/client/tilespec.c rulesetcrash/client/tilespec.c
--- freeciv-1.11.12/client/tilespec.c	Mon Aug  6 23:02:00 2001
+++ rulesetcrash/client/tilespec.c	Fri Aug 10 14:03:08 2001
@@ -121,7 +121,6 @@
 {
   char *tileset_default;
   char *fname, *dname;
-  int level;
 
   if (isometric_view_supported()) {
     tileset_default = "hires";    /* Do not i18n! --dwp */
@@ -142,19 +141,10 @@
   }
 
   if (strcmp(tileset_name, tileset_default)==0) {
-    level = LOG_FATAL;
-  } else {
-    level = LOG_ERROR;
-  }
-  freelog(level, _("Could not find readable file \"%s\" in data path."),
-	  fname);
-  freelog(level, _("The data path may be set via"
-		   " the environment variable FREECIV_PATH."));
-  freelog(level, _("Current data path is: \"%s\""), datafilename(NULL));
-  if (level == LOG_FATAL) {
+    freelog(LOG_FATAL, _("No useable default tileset found, aborting!"));
     exit(1);
   }
-  freelog(level, _("Trying \"%s\" tileset."), tileset_default);
+  freelog(LOG_ERROR, _("Trying \"%s\" tileset."), tileset_default);
   free(fname);
   return tilespec_fullname(tileset_default);
 }
diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/common/registry.c rulesetcrash/common/registry.c
--- freeciv-1.11.12/common/registry.c	Mon May 28 00:42:59 2001
+++ rulesetcrash/common/registry.c	Fri Aug 10 13:52:47 2001
@@ -368,7 +368,6 @@
 
   inf = inf_open(filename, datafilename);
   if (!inf) {
-    freelog(LOG_ERROR, "Could not open file \"%s\"", filename);
     return 0;
   }
   section_file_init(sf);
diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/common/shared.c rulesetcrash/common/shared.c
--- freeciv-1.11.12/common/shared.c	Sun Feb 18 17:28:30 2001
+++ rulesetcrash/common/shared.c	Fri Aug 10 14:02:28 2001
@@ -591,21 +591,25 @@
 ***************************************************************************/
 char *datafilename(const char *filename)
 {
-  static int init = 0;
+  static char *path = NULL;
   static int num_dirs = 0;
   static char **dirs = NULL;
   static struct astring realfile = ASTRING_INIT;
   int i;
 
-  if (!init) {
+  if (path == NULL) {
     char *tok;
-    char *path = getenv("FREECIV_PATH");
+    char *path2;
+
+    path = getenv("FREECIV_PATH");
     if (!path) {
       path = DEFAULT_DATA_PATH;
     }
-    path = mystrdup(path);	/* something we can strtok */
+    assert(path != NULL);
+
+    path2 = mystrdup(path);	/* something we can strtok */
     
-    tok = strtok(path, PATH_SEPARATOR);
+    tok = strtok(path2, PATH_SEPARATOR);
     do {
       int i;			/* strlen(tok), or -1 as flag */
       
@@ -651,8 +655,7 @@
       tok = strtok(NULL, PATH_SEPARATOR);
     } while(tok != NULL);
 
-    free(path);
-    init = 1;
+    free(path2);
   }
 
   if (filename == NULL) {
@@ -684,6 +687,13 @@
       return realfile.str;
     }
   }
+
+  freelog(LOG_ERROR, _("Could not find readable file \"%s\" in data path."),
+	    filename);
+  freelog(LOG_ERROR, _("The data path may be set via"
+			 " the environment variable FREECIV_PATH."));
+  freelog(LOG_ERROR, _("Current data path is: \"%s\""), datafilename(NULL));
+
   return NULL;
 }
 
@@ -701,11 +711,8 @@
   if (dname) {
     return dname;
   } else {
-    freelog(LOG_FATAL, _("Could not find readable file \"%s\" in data path."),
-	    filename);
-    freelog(LOG_FATAL, _("The data path may be set via"
-			 " the environment variable FREECIV_PATH."));
-    freelog(LOG_FATAL, _("Current data path is: \"%s\""), datafilename(NULL));
+    freelog(LOG_FATAL,
+		 _("The \"%s\" file is required ... aborting!"), filename);
     exit(1);
   }
 }
diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/server/ruleset.c rulesetcrash/server/ruleset.c
--- freeciv-1.11.12/server/ruleset.c	Sat Jul 21 20:31:57 2001
+++ rulesetcrash/server/ruleset.c	Fri Aug 10 14:15:06 2001
@@ -94,6 +94,30 @@
 static void send_ruleset_game(struct conn_list *dest);
 
 /**************************************************************************
+  datafilename() wrapper: tries to match in two ways.
+  Returns NULL on failure, the (statically allocated) filename on success.
+**************************************************************************/
+char *valid_ruleset_filename(char *subdir, char *whichset)
+{
+  char filename1[512], filename2[512], *dfilename;
+
+  my_snprintf(filename1, sizeof(filename1), "%s/%s.ruleset", subdir, whichset);
+  dfilename = datafilename(filename1);
+  if (dfilename)
+    return dfilename;
+
+  freelog(LOG_ERROR, _("Trying alternative ruleset filename syntax."));
+
+  my_snprintf(filename2, sizeof(filename2), "%s_%s.ruleset", subdir, whichset);
+  dfilename = datafilename(filename2);
+
+  if (dfilename)
+    return dfilename;
+
+  return(NULL);
+}
+
+/**************************************************************************
   Do initial section_file_load on a ruleset file.
   "subdir" = "default", "civ1", "custom", ...
   "whichset" = "techs", "units", "buildings", "terrain", ...
@@ -101,29 +125,22 @@
   This no longer returns the full filename opened; used secfile_filename()
   if you want it.
 **************************************************************************/
+
 static void openload_ruleset_file(struct section_file *file,
 				  char *subdir, char *whichset)
 {
-  char filename1[512], filename2[512], *dfilename;
   char sfilename[512];
+  char *dfilename = valid_ruleset_filename(subdir, whichset);
 
-  my_snprintf(filename1, sizeof(filename1), "%s_%s.ruleset", subdir, whichset);
-  dfilename = datafilename(filename1);
   if (!dfilename) {
-    my_snprintf(filename2, sizeof(filename2), "%s/%s.ruleset", subdir, whichset);
-    dfilename = datafilename(filename2);
-    if (!dfilename) {
-      freelog(LOG_FATAL,
-	      _("Could not find readable ruleset"
-		" file \"%s\" or \"%s\" in data path."), filename1, filename2);
-      freelog(LOG_FATAL, _("The data path may be set via"
-			   " the environment variable FREECIV_PATH."));
-      freelog(LOG_FATAL, _("Current data path is: \"%s\""), datafilename(NULL));
-      exit(1);
-    }
+    freelog(LOG_FATAL,
+	_("Could not find a readable \"%s\" ruleset file."), whichset);
+    exit(1);
   }
+
   /* Need to save a copy of the filename for following message, since
      section_file_load() may call datafilename() for includes. */
+
   sz_strlcpy(sfilename, dfilename);
   
   if (!section_file_load(file,sfilename)) {
diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/server/ruleset.h rulesetcrash/server/ruleset.h
--- freeciv-1.11.12/server/ruleset.h	Wed Aug  2 16:14:08 2000
+++ rulesetcrash/server/ruleset.h	Fri Aug 10 14:20:58 2001
@@ -18,4 +18,8 @@
 void load_rulesets(void);
 void send_rulesets(struct conn_list *dest);
 
+char *valid_ruleset_filename(char *subdir, char *whichset);
+  /* used as a partial pre-check on ruleset validity */
+  /* doesn't try to fall back on a default           */
+
 #endif  /* FC__RULESET_H */
diff -Nurd -Xfreeciv/diff_ignore freeciv-1.11.12/server/stdinhand.c rulesetcrash/server/stdinhand.c
--- freeciv-1.11.12/server/stdinhand.c	Tue Aug  7 15:35:06 2001
+++ rulesetcrash/server/stdinhand.c	Fri Aug 10 15:29:04 2001
@@ -47,6 +47,7 @@
 #include "meta.h"
 #include "plrhand.h"
 #include "report.h"
+#include "ruleset.h"
 #include "rulesout.h"
 #include "sernet.h"
 #include "srv_main.h"
@@ -102,11 +103,11 @@
 struct settings_s {
   char *name;
   int *value;
-  /* if the function is non-NULL the value should be modified through it.
-     The function returns whether the change was legal. The char * is
-     for returning an error message in the case of reject. */
+  /* Validating function for integer settings.  If the function is non-NULL,
+     it is called with the new value, and returns whether the change is
+     legal.  The char * is an error message in the case of reject. */
   int (*func_change)(int, char **);
-  /* The same, just for string settings. The first char* is the new
+  /* The same, for string settings. The first char* is the new
      value as an argument, the second is for returning the error
      message. */
   int (*func_change_s)(char *, char **);
@@ -134,8 +135,49 @@
   size_t sz_svalue;		/* max size we can write into svalue */
 };
 
+/********************************************************************
+Triggers used in settings_s.  valid_ruleset() is clumsy because of
+the fixed number of arguments and the reject_message - change? - rp
+*********************************************************************/
+
 static int autotoggle(int value, char **reject_message);
 
+static int valid_ruleset(char *whichset, char *subdir, char **reject_message)
+{
+  static char buffer[MAX_LEN_CONSOLE_LINE];
+
+  assert(subdir != NULL);
+
+  *reject_message = buffer;
+
+  if (!valid_ruleset_filename(subdir,whichset)) {
+    my_snprintf(buffer, sizeof(buffer),
+	_("Invalid ruleset subdirectory, keeping old value."));
+    return 0;
+  }
+
+  buffer[0] = '\0';
+
+  return 1;
+}
+
+static int valid_techs_ruleset(char *v, char **r_m)
+  { return valid_ruleset("techs",v,r_m); }
+static int valid_governments_ruleset(char *v, char **r_m)
+  { return valid_ruleset("governments",v,r_m); }
+static int valid_units_ruleset(char *v, char **r_m)
+  { return valid_ruleset("units",v,r_m); }
+static int valid_buildings_ruleset(char *v, char **r_m)
+  { return valid_ruleset("buildings",v,r_m); }
+static int valid_terrain_ruleset(char *v, char **r_m)
+  { return valid_ruleset("terrain",v,r_m); }
+static int valid_nations_ruleset(char *v, char **r_m)
+  { return valid_ruleset("nations",v,r_m); }
+static int valid_cities_ruleset(char *v, char **r_m)
+  { return valid_ruleset("cities",v,r_m); }
+static int valid_game_ruleset(char *v, char **r_m)
+  { return valid_ruleset("game",v,r_m); }
+
 #define SETTING_IS_INT(s) ((s)->value!=NULL)
 #define SETTING_IS_STRING(s) ((s)->value==NULL)
 
@@ -298,7 +340,7 @@
     N_("Number of initial advances per player"), "" },
 
 /* Various rules: these cannot be changed once the game has started. */
-  { "techs", NULL, NULL, NULL,
+  { "techs", NULL, NULL, valid_techs_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing techs.ruleset"),
@@ -310,7 +352,7 @@
     game.ruleset.techs, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.techs) },
 
-  { "governments", NULL, NULL, NULL,
+  { "governments", NULL, NULL, valid_governments_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing governments.ruleset"),
@@ -322,7 +364,7 @@
     game.ruleset.governments, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.governments) },
 
-  { "units", NULL, NULL, NULL,
+  { "units", NULL, NULL, valid_units_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing units.ruleset"),
@@ -334,7 +376,7 @@
     game.ruleset.units, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.units) },
 
-  { "buildings", NULL, NULL, NULL,
+  { "buildings", NULL, NULL, valid_buildings_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing buildings.ruleset"),
@@ -346,7 +388,7 @@
     game.ruleset.buildings, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.buildings) },
 
-  { "terrain", NULL, NULL, NULL,
+  { "terrain", NULL, NULL, valid_terrain_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing terrain.ruleset"),
@@ -358,7 +400,7 @@
     game.ruleset.terrain, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.terrain) },
 
-  { "nations", NULL, NULL, NULL,
+  { "nations", NULL, NULL, valid_nations_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing nations.ruleset"),
@@ -370,7 +412,7 @@
     game.ruleset.nations, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.nations) },
 
-  { "cities", NULL, NULL, NULL,
+  { "cities", NULL, NULL, valid_cities_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing cities.ruleset"),
@@ -381,7 +423,7 @@
     game.ruleset.cities, GAME_DEFAULT_RULESET,
     sizeof(game.ruleset.cities) },
 
-  { "game", NULL, NULL, NULL,
+  { "game", NULL, NULL, valid_game_ruleset,
     SSET_RULES, SSET_TO_CLIENT,
     0, 0, 0,
     N_("Data subdir containing game.ruleset"),