Second pass over run-time configuration system. Adjust priorities on some

option settings. Sort out SIGHUP vs BACKEND -- there is no total ordering
here, so make explicit checks. Add comments explaining all of this.
Removed permissions check on SHOW command.

Add examine_subclass to the game, rename to SQL_inheritance to fit the
official data model better. Adjust documentation.

Standalone backend needs to reset all options before it starts. To
facilitate that, have IsUnderPostmaster be set by the postmaster itself,
don't wait for the magic -p switch.

Also make sure that all environment variables and argv's survive
init_ps_display(). Use strdup where necessary.

Have initdb make configuration files (postgresql.conf, pg_hba.conf) mode
0600 -- having configuration files is no fun if you can't edit them.

1 files changed, 82 insertions, 50 deletions

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 300bb19b60a..f2cbe3651d3 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -4,7 +4,7 @@
  * Support for grand unified configuration scheme, including SET
  * command, configuration file, and command line options.
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.3 2000/06/15 04:10:30 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.4 2000/06/22 22:31:21 petere Exp $
  *
  * Copyright 2000 by PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
@@ -49,6 +49,7 @@ bool Show_executor_stats    = false;
 bool Show_query_stats       = false; /* this is sort of all three above together */
 bool Show_btree_build_stats = false;
 
+bool SQL_inheritance;
 
 
 enum config_type
@@ -115,6 +116,23 @@ struct config_string
 };
 
 
+/*
+ * TO ADD AN OPTION:
+ *
+ * 1. Declare a global variable of type bool, int, double, or char*
+ * and make use of it.
+ *
+ * 2. Decide at what times it's safe to set the option. See guc.h for
+ * details.
+ *
+ * 3. Decide on a name, a default value, upper and lower bounds (if
+ * applicable), etc.
+ *
+ * 4. Add a record below.
+ *
+ * 5. Don't forget to document that option.
+ */
+
 
 /******** option names follow ********/
 
@@ -133,27 +151,27 @@ ConfigureNamesBool[] =
 	{"geqo",                    PGC_USERSET,    &enable_geqo,           true},
 
 	{"net_server",              PGC_POSTMASTER, &NetServer,             false},
-	{"fsync",                   PGC_BACKEND,    &enableFsync,           true},
-
-	{"log_connections",         PGC_POSTMASTER, &Log_connections,       false},
-	{"log_timestamp",           PGC_BACKEND,    &Log_timestamp,         false},
-	{"log_pid",                 PGC_BACKEND,    &Log_pid,               false},
-
-	{"debug_print_query",       PGC_SUSET,      &Debug_print_query,     false},
-	{"debug_print_parse",       PGC_SUSET,      &Debug_print_parse,     false},
-	{"debug_print_rewritten",   PGC_SUSET,      &Debug_print_rewritten, false},
-	{"debug_print_plan",        PGC_SUSET,      &Debug_print_plan,      false},
-	{"debug_pretty_print",      PGC_SUSET,      &Debug_pretty_print,    false},
-
-	{"show_parser_stats",       PGC_SUSET,      &Show_parser_stats,     false},
-	{"show_planner_stats",      PGC_SUSET,      &Show_planner_stats,    false},
-	{"show_executor_stats",     PGC_SUSET,      &Show_executor_stats,   false},
-	{"show_query_stats",        PGC_SUSET,      &Show_query_stats,      false},
+	{"fsync",                   PGC_USERSET,    &enableFsync,           true},
+
+	{"log_connections",         PGC_SIGHUP,     &Log_connections,       false},
+	{"log_timestamp",           PGC_SIGHUP,     &Log_timestamp,         false},
+	{"log_pid",                 PGC_SIGHUP,     &Log_pid,               false},
+
+	{"debug_print_query",       PGC_USERSET,    &Debug_print_query,     false},
+	{"debug_print_parse",       PGC_USERSET,    &Debug_print_parse,     false},
+	{"debug_print_rewritten",   PGC_USERSET,    &Debug_print_rewritten, false},
+	{"debug_print_plan",        PGC_USERSET,    &Debug_print_plan,      false},
+	{"debug_pretty_print",      PGC_USERSET,    &Debug_pretty_print,    false},
+
+	{"show_parser_stats",       PGC_USERSET,    &Show_parser_stats,     false},
+	{"show_planner_stats",      PGC_USERSET,    &Show_planner_stats,    false},
+	{"show_executor_stats",     PGC_USERSET,    &Show_executor_stats,   false},
+	{"show_query_stats",        PGC_USERSET,    &Show_query_stats,      false},
 #ifdef BTREE_BUILD_STATS
 	{"show_btree_build_stats",  PGC_SUSET,      &Show_btree_build_stats, false},
 #endif
 
-	{"trace_notify",            PGC_SUSET,      &Trace_notify,          false},
+	{"trace_notify",            PGC_USERSET,    &Trace_notify,          false},
 
 #ifdef LOCK_DEBUG
 	{"trace_locks",             PGC_SUSET,      &Trace_locks,           false},
@@ -162,8 +180,10 @@ ConfigureNamesBool[] =
 	{"debug_deadlocks",         PGC_SUSET,      &Debug_deadlocks,       false},
 #endif
 
-	{"hostlookup",              PGC_POSTMASTER, &HostnameLookup,        false},
-	{"showportnumber",          PGC_POSTMASTER, &ShowPortNumber,        false},
+	{"hostlookup",              PGC_SIGHUP,     &HostnameLookup,        false},
+	{"showportnumber",          PGC_SIGHUP,     &ShowPortNumber,        false},
+
+	{"sql_inheritance",         PGC_USERSET,    &SQL_inheritance,       true},
 
 	{NULL, 0, NULL, false}
 };
@@ -187,7 +207,7 @@ ConfigureNamesInt[] =
 	 1000, 0, INT_MAX},
 
 #ifdef ENABLE_SYSLOG
-	{"syslog",                  PGC_POSTMASTER,         &Use_syslog,
+	{"syslog",                  PGC_SIGHUP,             &Use_syslog,
 	 0, 0, 2},
 #endif
 
@@ -203,11 +223,10 @@ ConfigureNamesInt[] =
 	{"port",                    PGC_POSTMASTER,         &PostPortName,
 	 DEF_PGPORT, 1, 65535},
 
-	/* XXX Is this really changeable at runtime? */
-	{"sort_mem",                PGC_SUSET,              &SortMem,
+	{"sort_mem",                PGC_USERSET,            &SortMem,
 	 512, 1, INT_MAX},
 
-	{"debug_level",             PGC_SUSET,              &DebugLvl,
+	{"debug_level",             PGC_USERSET,            &DebugLvl,
 	 0, 0, 16},
 
 #ifdef LOCK_DEBUG
@@ -217,7 +236,7 @@ ConfigureNamesInt[] =
 	 0, 0, INT_MAX},
 #endif
 	{"max_expr_depth",          PGC_USERSET,            &max_expr_depth,
-         DEFAULT_MAX_EXPR_DEPTH, 10, INT_MAX},
+	 DEFAULT_MAX_EXPR_DEPTH, 10, INT_MAX},
 
     {NULL, 0, NULL, 0, 0, 0}
 };
@@ -483,29 +502,45 @@ set_config_option(const char * name, const char * value, GucContext
 		return false;
 	}
 
-    if (record->context < context)
+	/*
+	 * Check if the option can be set at this time. See guc.h for the
+	 * precise rules. Note that we don't want to throw errors if we're
+	 * in the SIGHUP context. In that case we just ignore the attempt.
+	 */
+    if (record->context == PGC_POSTMASTER && context != PGC_POSTMASTER)
 	{
-        /* can't set option right now */
-		switch (context)
-		{
-			case PGC_USERSET:
-				elog(ERROR, "permission denied");
-				/*NORETURN*/
-            case PGC_SUSET:
-				elog(ERROR, "%s can only be set at startup", name);
-				/*NORETURN*/
-			case PGC_SIGHUP:
-				/* ignore the option */
-				return true;
-			case PGC_BACKEND:
-			    /* ignore; is this the right thing to do? */
-				return true;
-			default:
-				elog(FATAL, "%s:%d: internal error", __FILE__, __LINE__);
-				/*NORETURN*/
-		}
+		if (context != PGC_SIGHUP)
+			elog(ERROR, "%s cannot be changed after server start", name);
+		else
+			return true;
 	}
+	else if (record->context == PGC_SIGHUP && context != PGC_SIGHUP &&
+			 context != PGC_POSTMASTER)
+	{
+		elog(ERROR, "%s cannot be changed now", name);
+		/* Hmm, the idea of the SIGHUP context is "ought to be global,
+		 * but can be changed after postmaster start". But there's
+		 * nothing that prevents a crafty administrator from sending
+		 * SIGHUP signals to individual backends only. */
+	}
+	else if (record->context == PGC_BACKEND && context != PGC_BACKEND
+			 && context != PGC_POSTMASTER)
+	{
+		if (context != PGC_SIGHUP)
+			elog(ERROR, "%s cannot be set after connection start", name);
+		else
+			return true;
+	}
+	else if (record->context == PGC_SUSET && (context == PGC_USERSET
+											  || context == PGC_BACKEND))
+	{
+		elog(ERROR, "permission denied");
+	}
+
 
+	/*
+	 * Evaluate value and set variable
+	 */
     switch(type)
     {
         case PGC_BOOL:
@@ -652,7 +687,7 @@ SetConfigOption(const char * name, const char * value, GucContext
  * valid until the next call to configuration related functions.
  */
 const char *
-GetConfigOption(const char * name, bool issuper)
+GetConfigOption(const char * name)
 {
     struct config_generic * record;
 	static char buffer[256];
@@ -662,13 +697,10 @@ GetConfigOption(const char * name, bool issuper)
 	if (opttype == PGC_NONE)
 		elog(ERROR, "not a valid option name: %s", name);
 
-	if (record->context < PGC_USERSET && !issuper)
-		elog(ERROR, "permission denied");
-
 	switch(opttype)
     {
         case PGC_BOOL:
-            return *((struct config_bool *)record)->variable ? "true" : "false";
+            return *((struct config_bool *)record)->variable ? "on" : "off";
 
         case PGC_INT:
 			snprintf(buffer, 256, "%d", *((struct config_int *)record)->variable);