diff -u -r postgresql-7.3.2/src/backend/libpq/hba.c postgresql-7.3.2.ec/src/backend/libpq/hba.c
--- postgresql-7.3.2/src/backend/libpq/hba.c	Sat Dec 14 13:49:43 2002
+++ postgresql-7.3.2.ec/src/backend/libpq/hba.c	Mon Feb 17 09:30:15 2003
@@ -35,6 +35,7 @@
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
 #include "storage/fd.h"
+#include "utils/guc.h"
 
 
 #define IDENT_USERNAME_MAX 512
@@ -837,10 +838,20 @@
 	if (hba_lines)
 		free_lines(&hba_lines);
 
-	/* Put together the full pathname to the config file. */
-	bufsize = (strlen(DataDir) + strlen(CONF_FILE) + 2) * sizeof(char);
-	conf_file = (char *) palloc(bufsize);
-	snprintf(conf_file, bufsize, "%s/%s", DataDir, CONF_FILE);
+	/* Explicit HBA in config file */
+	if(explicit_hbafile && strlen(explicit_hbafile))
+	{
+		bufsize = strlen(explicit_hbafile)+1;
+		conf_file = (char *) palloc(bufsize);
+		strcpy(conf_file, explicit_hbafile);
+	}
+	else
+	{
+		/* put together the full pathname to the config file */
+		bufsize = (strlen(DataDir) + strlen(CONF_FILE) + 2) * sizeof(char);
+		conf_file = (char *) palloc(bufsize);
+		snprintf(conf_file, bufsize, "%s/%s", DataDir, CONF_FILE);
+	}
 
 	file = AllocateFile(conf_file, "r");
 	if (file == NULL)
@@ -979,10 +990,20 @@
 	if (ident_lines)
 		free_lines(&ident_lines);
 
-	/* put together the full pathname to the map file */
-	bufsize = (strlen(DataDir) + strlen(USERMAP_FILE) + 2) * sizeof(char);
-	map_file = (char *) palloc(bufsize);
-	snprintf(map_file, bufsize, "%s/%s", DataDir, USERMAP_FILE);
+	/* Explicit IDENT in config file */
+	if(explicit_identfile && strlen(explicit_identfile))
+	{
+		bufsize = strlen(explicit_identfile)+1;
+		map_file = (char *) palloc(bufsize);
+		strcpy(map_file, explicit_identfile);
+	}
+	else
+	{
+		/* put together the full pathname to the map file */
+		bufsize = (strlen(DataDir) + strlen(USERMAP_FILE) + 2) * sizeof(char);
+		map_file = (char *) palloc(bufsize);
+		snprintf(map_file, bufsize, "%s/%s", DataDir, USERMAP_FILE);
+	}
 
 	file = AllocateFile(map_file, "r");
 	if (file == NULL)
diff -u -r postgresql-7.3.2/src/backend/postmaster/postmaster.c postgresql-7.3.2.ec/src/backend/postmaster/postmaster.c
--- postgresql-7.3.2/src/backend/postmaster/postmaster.c	Wed Jan 15 19:27:17 2003
+++ postgresql-7.3.2.ec/src/backend/postmaster/postmaster.c	Mon Feb 17 09:30:15 2003
@@ -421,7 +421,7 @@
 
 	opterr = 1;
 
-	while ((opt = getopt(argc, argv, "A:a:B:b:c:D:d:Fh:ik:lm:MN:no:p:Ss-:")) != -1)
+	while ((opt = getopt(argc, argv, "A:a:B:b:C:c:D:d:Fh:ik:lm:MN:no:p:Ss-:")) != -1)
 	{
 		switch (opt)
 		{
@@ -441,6 +441,9 @@
 			case 'b':
 				/* Can no longer set the backend executable file to use. */
 				break;
+			case 'C': // MLW
+				explicit_pgconfig = optarg;
+				break;
 			case 'D':
 				potential_DataDir = optarg;
 				break;
@@ -564,13 +567,23 @@
 		ExitPostmaster(1);
 	}
 
-	/*
-	 * Now we can set the data directory, and then read postgresql.conf.
-	 */
-	checkDataDir(potential_DataDir);	/* issues error messages */
-	SetDataDir(potential_DataDir);
-
-	ProcessConfigFile(PGC_POSTMASTER);
+	if(explicit_pgconfig)
+	{
+		ProcessConfigFile(PGC_POSTMASTER);
+		if(!potential_DataDir && pgdatadir)
+			potential_DataDir = pgdatadir;
+		checkDataDir(potential_DataDir);	/* issues error messages */
+		SetDataDir(potential_DataDir);
+	}
+	else
+	{
+		/*
+		 * Now we can set the data directory, and then read postgresql.conf.
+		 */
+		checkDataDir(potential_DataDir);	/* issues error messages */
+		SetDataDir(potential_DataDir);
+		ProcessConfigFile(PGC_POSTMASTER);
+	}
 
 	/*
 	 * Check for invalid combinations of GUC settings.
diff -u -r postgresql-7.3.2/src/backend/utils/misc/guc-file.l postgresql-7.3.2.ec/src/backend/utils/misc/guc-file.l
--- postgresql-7.3.2/src/backend/utils/misc/guc-file.l	Tue Jul 30 12:33:08 2002
+++ postgresql-7.3.2.ec/src/backend/utils/misc/guc-file.l	Mon Feb 17 12:05:35 2003
@@ -116,51 +116,27 @@
 	}
 }
 
+#define ELEVEL_FROM_CONTEXT(ctx)	(ctx == PGC_SIGHUP) ? DEBUG3 : ERROR
 
-/*
- * Official function to read and process the configuration file. The
- * parameter indicates in what context the file is being read
- * (postmaster startup, backend startup, or SIGHUP). All options
- * mentioned in the configuration file are set to new values. This
- * function does not return if an error occurs. If an error occurs, no
- * values will be changed.
- */
-void
-ProcessConfigFile(GucContext context)
+static void 
+ReadConfigFile(char *filename, GucContext context)
 {
 	int token, parse_state;
 	char *opt_name, *opt_value;
-	char *filename;
 	struct name_value_pair *item, *head, *tail;
-	int elevel;
-	FILE * fp;
-
-	Assert(context == PGC_POSTMASTER || context == PGC_BACKEND 
-		|| context == PGC_SIGHUP);
-	Assert(DataDir);
-	elevel = (context == PGC_SIGHUP) ? DEBUG3 : ERROR;
+	FILE *fp;
+	int elevel = ELEVEL_FROM_CONTEXT(context);
 
-	/*
-	 * Open file
-	 */
-	filename = malloc(strlen(DataDir) + strlen(CONFIG_FILENAME) + 2);
-	if (filename == NULL)
-	{
-		elog(elevel, "out of memory");
-		return;
-	}
-	sprintf(filename, "%s/" CONFIG_FILENAME, DataDir);
-
-    fp = AllocateFile(filename, "r");
-    if (!fp)
-    {
+    	fp = AllocateFile(filename, "r");
+	if (!fp)
+    	{
+        	/* File not found is fine */
+        	if (errno != ENOENT)
+            		elog(elevel, "could not read configuration file %s: %s", 
+				filename, strerror(errno));
 		free(filename);
-        /* File not found is fine */
-        if (errno != ENOENT)
-            elog(elevel, "could not read configuration file `" CONFIG_FILENAME "': %s", strerror(errno));
 		return;
-    }
-
+    	}
 	/*
 	 * Parse
 	 */
@@ -189,7 +165,8 @@
                     token = yylex();
 
                 if (token != GUC_ID && token != GUC_STRING && 
-					token != GUC_INTEGER && token != GUC_REAL && 
+					token != GUC_INTEGER && 
+					token != GUC_REAL && 
 					token != GUC_UNQUOTED_STRING)
                     goto parse_error;
                 opt_value = strdup(yytext);
@@ -233,7 +210,6 @@
         }
 
 	FreeFile(fp);
-	free(filename);
 
 	/*
 	 * Check if all options are valid
@@ -256,7 +232,6 @@
 
  parse_error:
 	FreeFile(fp);
-	free(filename);
 	free_name_value_list(head);
 	elog(elevel, CONFIG_FILENAME ":%u: syntax error, token=\"%s\"", 
 		ConfigFileLineno,yytext);
@@ -264,12 +239,54 @@
 
  out_of_memory:
 	FreeFile(fp);
-	free(filename);
 	free_name_value_list(head);
 	elog(elevel, "out of memory");
 	return;
 }
+/*
+ * Official function to read and process the configuration file. The
+ * parameter indicates in what context the file is being read
+ * (postmaster startup, backend startup, or SIGHUP). All options
+ * mentioned in the configuration file are set to new values. This
+ * function does not return if an error occurs. If an error occurs, no
+ * values will be changed.
+ */
+void
+ProcessConfigFile(GucContext context)
+{
+	char *filename;
 
+	Assert(context == PGC_POSTMASTER || context == PGC_BACKEND 
+		|| context == PGC_SIGHUP);
+
+	/* Added for explicit config file */
+	if(explicit_pgconfig)
+	{
+		/*
+		 * Use explicit file
+		 */
+		filename = strdup(explicit_pgconfig);
+	}
+	else
+	{
+		/*
+		 * Use environmental config
+		 */
+		filename = malloc(strlen(DataDir) + strlen(CONFIG_FILENAME) + 2);
+		sprintf(filename, "%s/" CONFIG_FILENAME, DataDir);
+	}
+
+	if (filename == NULL)
+	{
+		int elevel = (context == PGC_SIGHUP) ? DEBUG3 : ERROR;
+		elog(elevel, "out of memory");
+		return;
+	}
+
+	ReadConfigFile(filename, context);
+
+	free(filename);
+}
 
 
 /* ----------------
diff -u -r postgresql-7.3.2/src/backend/utils/misc/guc.c postgresql-7.3.2.ec/src/backend/utils/misc/guc.c
--- postgresql-7.3.2/src/backend/utils/misc/guc.c	Tue Jan 28 13:04:13 2003
+++ postgresql-7.3.2.ec/src/backend/utils/misc/guc.c	Mon Feb 17 12:07:47 2003
@@ -51,6 +51,11 @@
 #include "utils/pg_locale.h"
 #include "pgstat.h"
 
+/* Added for config file only startup MLW */
+char *explicit_pgconfig = NULL;
+char *explicit_hbafile = NULL;
+char *explicit_identfile = NULL;
+char *pgdatadir = NULL;
 
 /* XXX these should be in other modules' header files */
 extern bool Log_connections;
@@ -113,6 +118,7 @@
 char	   *client_min_messages_str = NULL;
 const char	client_min_messages_str_default[] = "notice";
 
+static void ReadConfigFile(char *filename, GucContext context);
 
 #ifndef PG_KRB_SRVTAB
 #define PG_KRB_SRVTAB ""
@@ -146,7 +152,8 @@
 	PGC_BOOL,
 	PGC_INT,
 	PGC_REAL,
-	PGC_STRING
+	PGC_STRING,
+	PGC_FUNCTION
 };
 
 /* Generic fields applicable to all types of variables */
@@ -239,6 +246,13 @@
 	char	   *tentative_val;
 };
 
+struct config_function
+{
+	struct config_generic gen;
+	void (*function)(char *param, GucContext context);
+};
+
+
 /* Macros for freeing malloc'd pointers only if appropriate to do so */
 /* Some of these tests are probably redundant, but be safe ... */
 #define SET_STRING_VARIABLE(rec, newval) \
@@ -853,10 +867,32 @@
 	},
 
 	{
+		{"data_dir", PGC_POSTMASTER}, &pgdatadir,
+		"", NULL, NULL
+	},
+
+	{
+		{"hba_conf", PGC_POSTMASTER}, &explicit_hbafile,
+		"", NULL, NULL
+	},
+
+	{
+		{"ident_conf", PGC_POSTMASTER}, &explicit_identfile,
+		"", NULL, NULL
+	},
+
+	{
 		{NULL, 0}, NULL, NULL, NULL, NULL
 	}
 };
 
+
+static struct config_function ConfigureFunctions[] =
+{
+	{ {"include", PGC_POSTMASTER}, ReadConfigFile},
+	{ {NULL,0}, NULL}
+};
+
 /******** end of options list ********/
 
 
@@ -919,6 +955,12 @@
 		conf->gen.vartype = PGC_STRING;
 		num_vars++;
 	}
+	for(i = 0; ConfigureFunctions[i].gen.name; i++)
+	{
+		struct config_function *conf = &ConfigureFunctions[i];
+		conf->gen.vartype = PGC_FUNCTION;
+		num_vars++;
+	}
 
 	guc_vars = (struct config_generic **)
 		malloc(num_vars * sizeof(struct config_generic *));
@@ -939,6 +981,9 @@
 	for (i = 0; ConfigureNamesString[i].gen.name; i++)
 		guc_vars[num_vars++] = &ConfigureNamesString[i].gen;
 
+	for (i = 0; ConfigureFunctions[i].gen.name; i++)
+		guc_vars[num_vars++] = &ConfigureFunctions[i].gen;
+
 	qsort((void *) guc_vars, num_vars, sizeof(struct config_generic *),
 		  guc_var_compare);
 
@@ -1135,6 +1180,8 @@
 					conf->session_val = str;
 					break;
 				}
+			case PGC_FUNCTION: /* Nothing to do */
+				break;
 		}
 	}
 
@@ -1280,6 +1327,8 @@
 					guc_dirty = true;
 					break;
 				}
+			case PGC_FUNCTION: /* Nothing to do */
+				break;
 		}
 	}
 }
@@ -1421,6 +1470,8 @@
 					conf->gen.status = 0;
 					break;
 				}
+			case	PGC_FUNCTION: /* Nothing to do */
+				break;
 		}
 	}
 
@@ -1684,6 +1735,17 @@
 	 */
 	switch (record->vartype)
 	{
+		case PGC_FUNCTION:
+			if(!DoIt)
+			{
+				/* During the "checking" stage of configuration
+				 * read, run functions 
+				 */
+				struct config_function *fn = 
+					(struct config_function *)record;
+				fn->function((char *)value, context);
+			}
+			break;
 		case PGC_BOOL:
 			{
 				struct config_bool *conf = (struct config_bool *) record;
@@ -2063,6 +2125,9 @@
 
 		case PGC_STRING:
 			return *((struct config_string *) record)->variable;
+		case PGC_FUNCTION:
+			/* Should never really happen */
+			return NULL;
 	}
 	return NULL;
 }
@@ -2097,6 +2162,9 @@
 
 		case PGC_STRING:
 			return ((struct config_string *) record)->reset_val;
+		case PGC_FUNCTION:
+			/* Should never really happen */
+			return NULL;
 	}
 	return NULL;
 }
diff -u -r postgresql-7.3.2/src/backend/utils/misc/postgresql.conf.sample postgresql-7.3.2.ec/src/backend/utils/misc/postgresql.conf.sample
--- postgresql-7.3.2/src/backend/utils/misc/postgresql.conf.sample	Mon Jan 27 22:44:09 2003
+++ postgresql-7.3.2.ec/src/backend/utils/misc/postgresql.conf.sample	Mon Feb 17 12:04:44 2003
@@ -23,6 +23,21 @@
 
 #========================================================================
 
+# Allows PostgreSQL to include another file
+# include = '/somedir/pgdefs.conf'
+
+# Allows PostgreSQL to use a pg_hba.conf file
+# which is not in the database directory.
+# hba_conf = '/etc/postgres/pg_hba.conf'
+
+# Allows PostgreSQL to use a pg_ident.conf file
+# which is not in the database directory.
+# ident_conf = '/etc/postgres/pg_ident.conf'
+
+# Allows Postgres to find its data directory
+# from this configuration file.
+# data_dir = '/RAID0/postgres'
+
 
 #
 #	Connection Parameters
diff -u -r postgresql-7.3.2/src/include/utils/guc.h postgresql-7.3.2.ec/src/include/utils/guc.h
--- postgresql-7.3.2/src/include/utils/guc.h	Mon Oct 21 14:57:35 2002
+++ postgresql-7.3.2.ec/src/include/utils/guc.h	Mon Feb 17 11:41:13 2003
@@ -137,5 +137,10 @@
 extern char *client_min_messages_str;
 
 extern const char client_min_messages_str_default[];
+/* Added MLW */
+extern char *explicit_pgconfig;
+extern char *explicit_hbafile;
+extern char *explicit_identfile;
+extern char *pgdatadir;
 
 #endif   /* GUC_H */