Custom variable class segmentation fault

Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v
retrieving revision 1.339
diff -c -c -r1.339 guc.c
*** src/backend/utils/misc/guc.c	13 Aug 2006 02:22:24 -0000	1.339
--- src/backend/utils/misc/guc.c	13 Aug 2006 15:34:13 -0000
***************
*** 5512,5518 ****
  		{
  			struct config_string *conf = (struct config_string *) record;
  
! 			return strcmp(*conf->variable, newvalue) == 0;
  		}
  	}
  
--- 5512,5521 ----
  		{
  			struct config_string *conf = (struct config_string *) record;
  
! 			if (!*conf->variable)	/* custom variable with no value yet */
! 				return false;
! 			else
! 				return strcmp(*conf->variable, newvalue) == 0;
  		}
  	}
  

Index: src/backend/utils/misc/guc-file.l
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/misc/guc-file.l,v
retrieving revision 1.42
retrieving revision 1.43
diff -c -r1.42 -r1.43
*** src/backend/utils/misc/guc-file.l	12 Aug 2006 04:12:41 -0000	1.42
--- src/backend/utils/misc/guc-file.l	13 Aug 2006 01:30:17 -0000	1.43
***************
*** 4,10 ****
   *
   * Copyright (c) 2000-2006, PostgreSQL Global Development Group
   *
!  * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.42 2006/08/12 04:12:41 momjian Exp $
   */
  
  %{
--- 4,10 ----
   *
   * Copyright (c) 2000-2006, PostgreSQL Global Development Group
   *
!  * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.43 2006/08/13 01:30:17 momjian Exp $
   */
  
  %{
***************
*** 50,56 ****
  static bool ParseConfigFile(const char *config_file, const char *calling_file,
  							int depth, GucContext context, int elevel,
  							struct name_value_pair **head_p,
! 							struct name_value_pair **tail_p);
  static void free_name_value_list(struct name_value_pair * list);
  static char *GUC_scanstr(const char *s);
  
--- 50,57 ----
  static bool ParseConfigFile(const char *config_file, const char *calling_file,
  							int depth, GucContext context, int elevel,
  							struct name_value_pair **head_p,
! 							struct name_value_pair **tail_p,
! 							int *varcount);
  static void free_name_value_list(struct name_value_pair * list);
  static char *GUC_scanstr(const char *s);
  
***************
*** 114,121 ****
  void
  ProcessConfigFile(GucContext context)
  {
! 	int			elevel;
  	struct name_value_pair *item, *head, *tail;
  
  	Assert(context == PGC_POSTMASTER || context == PGC_SIGHUP);
  
--- 115,124 ----
  void
  ProcessConfigFile(GucContext context)
  {
! 	int			elevel, i;
  	struct name_value_pair *item, *head, *tail;
+ 	bool	   *apply_list = NULL;
+ 	int			varcount = 0;
  
  	Assert(context == PGC_POSTMASTER || context == PGC_SIGHUP);
  
***************
*** 134,158 ****
  
  	if (!ParseConfigFile(ConfigFileName, NULL,
  						 0, context, elevel,
! 						 &head, &tail))
  		goto cleanup_list;
  
  	/* Check if all options are valid */
! 	for (item = head; item; item = item->next)
  	{
! 		if (!set_config_option(item->name, item->value, context,
! 							   PGC_S_FILE, false, false))
  			goto cleanup_list;
  	}
  
  	/* If we got here all the options checked out okay, so apply them. */
! 	for (item = head; item; item = item->next)
! 	{
! 		set_config_option(item->name, item->value, context,
! 						  PGC_S_FILE, false, true);
! 	}
  
!  cleanup_list:
  	free_name_value_list(head);
  }
  
--- 137,192 ----
  
  	if (!ParseConfigFile(ConfigFileName, NULL,
  						 0, context, elevel,
! 						 &head, &tail, &varcount))
  		goto cleanup_list;
  
+ 	/* Can we allocate memory here, what about leaving here prematurely? */
+ 	apply_list = (bool *) palloc(sizeof(bool) * varcount);
+ 
  	/* Check if all options are valid */
! 	for (item = head, i = 0; item; item = item->next, i++)
  	{
! 		bool isEqual, isContextOk;
! 
! 		if (!verify_config_option(item->name, item->value, context,
! 						  PGC_S_FILE, &isEqual, &isContextOk))
! 		{
! 			ereport(elevel,
! 				(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
! 				errmsg("configuration file is invalid")));
  			goto cleanup_list;
+ 		}
+ 
+ 		if (isContextOk == false)
+ 		{
+ 			apply_list[i] = false;
+ 			if (context == PGC_SIGHUP)
+ 			{
+ 				if (isEqual == false)
+ 					ereport(elevel,
+ 						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
+ 						errmsg("parameter \"%s\" cannot be changed after server start; configuration file change ignored",
+ 						item->name)));
+ 			}
+ 			else
+ 				/* if it is boot phase, context must be valid for all
+ 				 * configuration item. */
+ 				goto cleanup_list;
+ 		}
+ 		else
+ 			apply_list[i] = true;
  	}
  
  	/* If we got here all the options checked out okay, so apply them. */
! 	for (item = head, i = 0; item; item = item->next, i++)
! 		if (apply_list[i])
! 			set_config_option(item->name, item->value, context,
! 							  PGC_S_FILE, false, true);
! 
  
! cleanup_list:
! 	if (apply_list)
! 		pfree(apply_list);
  	free_name_value_list(head);
  }
  
***************
*** 189,201 ****
  ParseConfigFile(const char *config_file, const char *calling_file,
  				int depth, GucContext context, int elevel,
  				struct name_value_pair **head_p,
! 				struct name_value_pair **tail_p)
  {
! 	bool		OK = true;
! 	char		abs_path[MAXPGPATH];
! 	FILE	   *fp;
  	YY_BUFFER_STATE lex_buffer;
! 	int			token;
  
  	/*
  	 * Reject too-deep include nesting depth.  This is just a safety check
--- 223,236 ----
  ParseConfigFile(const char *config_file, const char *calling_file,
  				int depth, GucContext context, int elevel,
  				struct name_value_pair **head_p,
! 				struct name_value_pair **tail_p,
! 				int *varcount)
  {
! 	bool			OK = true;
! 	char			abs_path[MAXPGPATH];
! 	FILE		   *fp;
  	YY_BUFFER_STATE lex_buffer;
! 	int				token;
  
  	/*
  	 * Reject too-deep include nesting depth.  This is just a safety check
***************
*** 289,295 ****
  
  			if (!ParseConfigFile(opt_value, config_file,
  								 depth + 1, context, elevel,
! 								 head_p, tail_p))
  			{
  				pfree(opt_name);
  				pfree(opt_value);
--- 324,330 ----
  
  			if (!ParseConfigFile(opt_value, config_file,
  								 depth + 1, context, elevel,
! 								 head_p, tail_p, varcount))
  			{
  				pfree(opt_name);
  				pfree(opt_value);
***************
*** 333,338 ****
--- 368,374 ----
  			else
  				(*tail_p)->next = item;
  			*tail_p = item;
+ 			(*varcount)++;
  		}
  
  		/* break out of loop if read EOF, else loop for next line */
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v
retrieving revision 1.337
retrieving revision 1.338
diff -c -r1.337 -r1.338
*** src/backend/utils/misc/guc.c	12 Aug 2006 04:12:41 -0000	1.337
--- src/backend/utils/misc/guc.c	13 Aug 2006 01:30:17 -0000	1.338
***************
*** 10,16 ****
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.337 2006/08/12 04:12:41 momjian Exp $
   *
   *--------------------------------------------------------------------
   */
--- 10,16 ----
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.338 2006/08/13 01:30:17 momjian Exp $
   *
   *--------------------------------------------------------------------
   */
***************
*** 2313,2319 ****
   * states).
   */
  static void
! set_string_field(struct config_string * conf, char **field, char *newval)
  {
  	char	   *oldval = *field;
  	GucStack   *stack;
--- 2313,2319 ----
   * states).
   */
  static void
! set_string_field(struct config_string *conf, char **field, char *newval)
  {
  	char	   *oldval = *field;
  	GucStack   *stack;
***************
*** 2535,2542 ****
  	gen = &var->gen;
  	memset(var, 0, sz);
  
! 	gen->name = guc_strdup(elevel, name);
! 	if (gen->name == NULL)
  	{
  		free(var);
  		return NULL;
--- 2535,2541 ----
  	gen = &var->gen;
  	memset(var, 0, sz);
  
! 	if ((gen->name = guc_strdup(elevel, name)) == NULL)
  	{
  		free(var);
  		return NULL;
***************
*** 3690,3785 ****
  	return result;
  }
  
- 
  /*
!  * Sets option `name' to given value. The value should be a string
!  * which is going to be parsed and converted to the appropriate data
!  * type.  The context and source parameters indicate in which context this
!  * function is being called so it can apply the access restrictions
!  * properly.
!  *
!  * If value is NULL, set the option to its default value. If the
!  * parameter changeVal is false then don't really set the option but do all
!  * the checks to see if it would work.
!  *
!  * If there is an error (non-existing option, invalid value) then an
!  * ereport(ERROR) is thrown *unless* this is called in a context where we
!  * don't want to ereport (currently, startup or SIGHUP config file reread).
!  * In that case we write a suitable error message via ereport(DEBUG) and
!  * return false. This is working around the deficiencies in the ereport
!  * mechanism, so don't blame me.  In all other cases, the function
!  * returns true, including cases where the input is valid but we chose
!  * not to apply it because of context or source-priority considerations.
!  *
!  * See also SetConfigOption for an external interface.
   */
! bool
! set_config_option(const char *name, const char *value,
! 				  GucContext context, GucSource source,
! 				  bool isLocal, bool changeVal)
  {
! 	struct config_generic *record;
! 	int			elevel;
! 	bool		makeDefault;
! 
! 	if (context == PGC_SIGHUP || source == PGC_S_DEFAULT)
  	{
! 		/*
! 		 * To avoid cluttering the log, only the postmaster bleats loudly
! 		 * about problems with the config file.
! 		 */
! 		elevel = IsUnderPostmaster ? DEBUG2 : LOG;
! 	}
! 	else if (source == PGC_S_DATABASE || source == PGC_S_USER)
! 		elevel = INFO;
! 	else
! 		elevel = ERROR;
  
! 	record = find_option(name, elevel);
! 	if (record == NULL)
! 	{
! 		ereport(elevel,
! 				(errcode(ERRCODE_UNDEFINED_OBJECT),
! 			   errmsg("unrecognized configuration parameter \"%s\"", name)));
! 		return false;
  	}
  
! 	/*
! 	 * 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 and return true.
! 	 */
  	switch (record->context)
  	{
  		case PGC_INTERNAL:
- 			if (context == PGC_SIGHUP)
- 				return true;
  			if (context != PGC_INTERNAL)
  			{
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be changed",
! 								name)));
  				return false;
  			}
  			break;
  		case PGC_POSTMASTER:
  			if (context == PGC_SIGHUP)
! 			{
! 				if (changeVal && !is_newvalue_equal(record, value))
! 					ereport(elevel,
! 							(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
! 							 errmsg("parameter \"%s\" cannot be changed after server start; configuration file change ignored",
! 									name)));
  
- 				return true;
- 			}
  			if (context != PGC_POSTMASTER)
  			{
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be changed after server start",
! 								name)));
  				return false;
  			}
  			break;
--- 3689,3942 ----
  	return result;
  }
  
  /*
!  * Try to parse value. Determine what is type and call related
!  * parsing function or if newval is equal to NULL, reset value 
!  * to default or bootval. If the value parsed okay return true,
!  * else false.
   */
! static bool
! parse_value(int elevel, const struct config_generic *record, 
! 		const char *value, GucSource *source, bool changeVal, 
! 		union config_var_value *retval)
  {
! 	/*
! 	 * Evaluate value and set variable.
! 	 */
! 	switch (record->vartype)
  	{
! 		case PGC_BOOL:
! 			{
! 				struct config_bool *conf = (struct config_bool *) record;
! 				bool		newval;
  
! 				if (value)
! 				{
! 					if (!parse_bool(value, &newval))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						  errmsg("parameter \"%s\" requires a Boolean value",
! 								 record->name)));
! 						return false;
! 					}
! 				}
! 				else
! 				{
! 					newval = conf->reset_val;
! 					*source = conf->gen.reset_source;
! 				}
! 
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, *source))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 							 errmsg("invalid value for parameter \"%s\": %d",
! 									record->name, (int) newval)));
! 						return false;
! 					}
! 				if (retval)
! 					retval->boolval = newval;
! 				break;
! 			}
! 
! 		case PGC_INT:
! 			{
! 				struct config_int *conf = (struct config_int *) record;
! 				int			newval;
! 
! 				if (value)
! 				{
! 					if (!parse_int(value, &newval, conf->gen.flags))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						 errmsg("parameter \"%s\" requires an integer value",
! 								record->name)));
! 						return false;
! 					}
! 					if (newval < conf->min || newval > conf->max)
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 								 errmsg("%d is outside the valid range for parameter \"%s\" (%d .. %d)",
! 										newval, record->name, conf->min, conf->max)));
! 						return false;
! 					}
! 				}
! 				else
! 				{
! 					newval = conf->reset_val;
! 					*source = conf->gen.reset_source;
! 				}
! 
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, *source))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 							 errmsg("invalid value for parameter \"%s\": %d",
! 									record->name, newval)));
! 						return false;
! 					}
! 				if (retval)
! 					retval->intval = newval;
! 				break;
! 			}
! 
! 		case PGC_REAL:
! 			{
! 				struct config_real *conf = (struct config_real *) record;
! 				double		newval;
! 
! 				if (value)
! 				{
! 					if (!parse_real(value, &newval))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						  errmsg("parameter \"%s\" requires a numeric value",
! 								 record->name)));
! 						return false;
! 					}
! 					if (newval < conf->min || newval > conf->max)
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 								 errmsg("%g is outside the valid range for parameter \"%s\" (%g .. %g)",
! 										newval, record->name, conf->min, conf->max)));
! 						return false;
! 					}
! 				}
! 				else
! 				{
! 					newval = conf->reset_val;
! 					*source = conf->gen.reset_source;
! 				}
! 
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, *source))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 							 errmsg("invalid value for parameter \"%s\": %g",
! 									record->name, newval)));
! 						return false;
! 					}
! 				if (retval)
! 					retval->realval = newval;
! 				break;
! 			}
! 
! 		case PGC_STRING:
! 			{
! 				struct config_string *conf = (struct config_string *) record;
! 				char	   *newval;
! 
! 				if (value)
! 				{
! 					if ((newval = guc_strdup(elevel, value)) == NULL)
! 						return false;
! 					/*
! 					 * The only sort of "parsing" check we need to do is
! 					 * apply truncation if GUC_IS_NAME.
! 					 */
! 					if (conf->gen.flags & GUC_IS_NAME)
! 						truncate_identifier(newval, strlen(newval), true);
! 				}
! 				else if (conf->reset_val)
! 				{
! 					/*
! 					 * We could possibly avoid strdup here, but easier to make
! 					 * this case work the same as the normal assignment case.
! 					 */
! 					if ((newval = guc_strdup(elevel, conf->reset_val)) == NULL)
! 						return false;
! 					*source = conf->gen.reset_source;
! 				}
! 				else
! 				{
! 					/* Nothing to reset to, as yet; so do nothing */
! 					break;
! 				}
! 
! 				if (conf->assign_hook)
! 				{
! 					const char *hookresult;
! 
! 					/*
! 					 * If the hook ereports, we have to make sure we free
! 					 * newval, else it will be a permanent memory leak.
! 					 */
! 					hookresult = call_string_assign_hook(conf->assign_hook,
! 														 newval,
! 														 changeVal,
! 														 *source);
! 					if (hookresult == NULL)
! 					{
! 						free(newval);
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						 errmsg("invalid value for parameter \"%s\": \"%s\"",
! 								record->name, value ? value : "")));
! 						return false;
! 					}
! 					else if (hookresult != newval)
! 					{
! 						free(newval);
! 
! 						/*
! 						 * Having to cast away const here is annoying, but the
! 						 * alternative is to declare assign_hooks as returning
! 						 * char*, which would mean they'd have to cast away
! 						 * const, or as both taking and returning char*, which
! 						 * doesn't seem attractive either --- we don't want
! 						 * them to scribble on the passed str.
! 						 */
! 						newval = (char *) hookresult;
! 					}
! 				}
! 
! 				if (retval)
! 					retval->stringval = newval;
! 				else
! 					free(newval);
! 				break;
! 			}
  	}
+ 	return true;
+ }
  
! /*
!  * Check if the option can be set at this time. See guc.h for the precise
!  * rules. 
!  */
! static bool
! checkContext(int elevel, struct config_generic *record, GucContext context)
! {
  	switch (record->context)
  	{
  		case PGC_INTERNAL:
  			if (context != PGC_INTERNAL)
  			{
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be changed",
! 								record->name)));
  				return false;
  			}
  			break;
  		case PGC_POSTMASTER:
  			if (context == PGC_SIGHUP)
! 				return false;
  
  			if (context != PGC_POSTMASTER)
  			{
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be changed after server start",
! 								record->name)));
  				return false;
  			}
  			break;
***************
*** 3789,3795 ****
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be changed now",
! 								name)));
  				return false;
  			}
  
--- 3946,3952 ----
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be changed now",
! 								record->name)));
  				return false;
  			}
  
***************
*** 3812,3825 ****
  				 * backend start.
  				 */
  				if (IsUnderPostmaster)
! 					return true;
  			}
  			else if (context != PGC_BACKEND && context != PGC_POSTMASTER)
  			{
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be set after connection start",
! 								name)));
  				return false;
  			}
  			break;
--- 3969,3984 ----
  				 * backend start.
  				 */
  				if (IsUnderPostmaster)
! 				{
! 					return false;
! 				}
  			}
  			else if (context != PGC_BACKEND && context != PGC_POSTMASTER)
  			{
  				ereport(elevel,
  						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
  						 errmsg("parameter \"%s\" cannot be set after connection start",
! 								record->name)));
  				return false;
  			}
  			break;
***************
*** 3829,3835 ****
  				ereport(elevel,
  						(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  						 errmsg("permission denied to set parameter \"%s\"",
! 								name)));
  				return false;
  			}
  			break;
--- 3988,3994 ----
  				ereport(elevel,
  						(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  						 errmsg("permission denied to set parameter \"%s\"",
! 								record->name)));
  				return false;
  			}
  			break;
***************
*** 3837,3842 ****
--- 3996,4109 ----
  			/* always okay */
  			break;
  	}
+ 	return true;
+ }
+ 
+ /*
+  * Get error level for different sources and context.
+  */
+ static int
+ get_elevel(GucContext context, GucSource source)
+ {
+ 	int elevel;
+ 	if (context == PGC_SIGHUP || source == PGC_S_DEFAULT)
+ 	{
+ 		/*
+ 		 * To avoid cluttering the log, only the postmaster bleats loudly
+ 		 * about problems with the config file.
+ 		 */
+ 		elevel = IsUnderPostmaster ? DEBUG2 : LOG;
+ 	}
+ 	else if (source == PGC_S_DATABASE || source == PGC_S_USER)
+ 		elevel = INFO;
+ 	else
+ 		elevel = ERROR;
+ 
+ 	return elevel;
+ }
+ 
+ /*
+  * Verify if option exists and value is valid.
+  * It is primary used for validation of items in configuration file.
+  */
+ bool
+ verify_config_option(const char *name, const char *value,
+ 				GucContext context, GucSource source,
+ 				bool *isNewEqual, bool *isContextOK)
+ {
+ 	int					   elevel;
+ 	struct config_generic *record;
+ 
+ 	elevel = get_elevel(context, source);
+ 
+ 	record = find_option(name, elevel);
+ 	if (record == NULL)
+ 	{
+ 		ereport(elevel,
+ 				(errcode(ERRCODE_UNDEFINED_OBJECT),
+ 			   errmsg("unrecognized configuration parameter \"%s\"", name)));
+ 		return false;
+ 	}
+ 
+ 	if (parse_value(elevel, record, value, &source, false, NULL))
+ 	{
+ 		if (isNewEqual != NULL)
+ 			*isNewEqual = is_newvalue_equal(record, value);
+ 		if (isContextOK != NULL)
+ 			*isContextOK = checkContext(elevel, record, context);
+ 	}
+ 	else 
+ 		return false;
+ 
+     return true;
+ }
+ 
+ 
+ /*
+  * Sets option `name' to given value. The value should be a string
+  * which is going to be parsed and converted to the appropriate data
+  * type.  The context and source parameters indicate in which context this
+  * function is being called so it can apply the access restrictions
+  * properly.
+  *
+  * If value is NULL, set the option to its default value. If the
+  * parameter changeVal is false then don't really set the option but do all
+  * the checks to see if it would work.
+  *
+  * If there is an error (non-existing option, invalid value) then an
+  * ereport(ERROR) is thrown *unless* this is called in a context where we
+  * don't want to ereport (currently, startup or SIGHUP config file reread).
+  * In that case we write a suitable error message via ereport(DEBUG) and
+  * return false. This is working around the deficiencies in the ereport
+  * mechanism, so don't blame me.  In all other cases, the function
+  * returns true, including cases where the input is valid but we chose
+  * not to apply it because of context or source-priority considerations.
+  *
+  * See also SetConfigOption for an external interface.
+  */
+ bool
+ set_config_option(const char *name, const char *value,
+ 				  GucContext context, GucSource source,
+ 				  bool isLocal, bool changeVal)
+ {
+ 	struct config_generic *record;
+ 	int			elevel;
+ 	bool		makeDefault;
+ 
+ 	elevel = get_elevel(context, source);
+ 
+ 	record = find_option(name, elevel);
+ 	if (record == NULL)
+ 	{
+ 		ereport(elevel,
+ 				(errcode(ERRCODE_UNDEFINED_OBJECT),
+ 			   errmsg("unrecognized configuration parameter \"%s\"", name)));
+ 		return false;
+ 	}
+ 
+ 	/* Check if change is allowed in the running context. */
+ 	if (!checkContext(elevel, record, context))
+ 		return false;
  
  	/*
  	 * Should we set reset/stacked values?	(If so, the behavior is not
***************
*** 3871,3914 ****
  			{
  				struct config_bool *conf = (struct config_bool *) record;
  				bool		newval;
! 
! 				if (value)
! 				{
! 					if (!parse_bool(value, &newval))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						  errmsg("parameter \"%s\" requires a Boolean value",
! 								 name)));
! 						return false;
! 					}
! 				}
! 				else
! 				{
! 					newval = conf->reset_val;
! 					source = conf->gen.reset_source;
! 				}
! 
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, source))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 							 errmsg("invalid value for parameter \"%s\": %d",
! 									name, (int) newval)));
! 						return false;
! 					}
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
  					if (changeVal)
  					{
  						*conf->variable = newval;
  						conf->gen.source = source;
  					}
  					if (makeDefault)
  					{
  						GucStack   *stack;
--- 4138,4160 ----
  			{
  				struct config_bool *conf = (struct config_bool *) record;
  				bool		newval;
! 				
! 				if (!parse_value(elevel, record, value, &source, changeVal,
! 					(union config_var_value*) &newval))
! 					return false;
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
+ 
  					if (changeVal)
  					{
  						*conf->variable = newval;
  						conf->gen.source = source;
  					}
+ 
  					if (makeDefault)
  					{
  						GucStack   *stack;
***************
*** 3948,3998 ****
  				struct config_int *conf = (struct config_int *) record;
  				int			newval;
  
! 				if (value)
! 				{
! 					if (!parse_int(value, &newval, conf->gen.flags))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						 errmsg("parameter \"%s\" requires an integer value",
! 								name)));
! 						return false;
! 					}
! 					if (newval < conf->min || newval > conf->max)
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 								 errmsg("%d is outside the valid range for parameter \"%s\" (%d .. %d)",
! 										newval, name, conf->min, conf->max)));
! 						return false;
! 					}
! 				}
! 				else
! 				{
! 					newval = conf->reset_val;
! 					source = conf->gen.reset_source;
! 				}
! 
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, source))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 							 errmsg("invalid value for parameter \"%s\": %d",
! 									name, newval)));
! 						return false;
! 					}
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
  					if (changeVal)
  					{
  						*conf->variable = newval;
  						conf->gen.source = source;
  					}
  					if (makeDefault)
  					{
  						GucStack   *stack;
--- 4194,4215 ----
  				struct config_int *conf = (struct config_int *) record;
  				int			newval;
  
!  				if (!parse_value(elevel, record, value, &source, changeVal,
! 					(union config_var_value*) &newval))
!  					return false;
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
+ 
  					if (changeVal)
  					{
  						*conf->variable = newval;
  						conf->gen.source = source;
  					}
+ 
  					if (makeDefault)
  					{
  						GucStack   *stack;
***************
*** 4032,4082 ****
  				struct config_real *conf = (struct config_real *) record;
  				double		newval;
  
! 				if (value)
! 				{
! 					if (!parse_real(value, &newval))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						  errmsg("parameter \"%s\" requires a numeric value",
! 								 name)));
! 						return false;
! 					}
! 					if (newval < conf->min || newval > conf->max)
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 								 errmsg("%g is outside the valid range for parameter \"%s\" (%g .. %g)",
! 										newval, name, conf->min, conf->max)));
! 						return false;
! 					}
! 				}
! 				else
! 				{
! 					newval = conf->reset_val;
! 					source = conf->gen.reset_source;
! 				}
! 
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, source))
! 					{
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 							 errmsg("invalid value for parameter \"%s\": %g",
! 									name, newval)));
! 						return false;
! 					}
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
  					if (changeVal)
  					{
  						*conf->variable = newval;
  						conf->gen.source = source;
  					}
  					if (makeDefault)
  					{
  						GucStack   *stack;
--- 4249,4270 ----
  				struct config_real *conf = (struct config_real *) record;
  				double		newval;
  
! 				if (!parse_value(elevel, record, value, &source, changeVal,
! 					(union config_var_value*) &newval))
! 					return false; 
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
+ 
  					if (changeVal)
  					{
  						*conf->variable = newval;
  						conf->gen.source = source;
  					}
+ 
  					if (makeDefault)
  					{
  						GucStack   *stack;
***************
*** 4116,4197 ****
  				struct config_string *conf = (struct config_string *) record;
  				char	   *newval;
  
! 				if (value)
! 				{
! 					newval = guc_strdup(elevel, value);
! 					if (newval == NULL)
! 						return false;
! 					/*
! 					 * The only sort of "parsing" check we need to do is
! 					 * apply truncation if GUC_IS_NAME.
! 					 */
! 					if (conf->gen.flags & GUC_IS_NAME)
! 						truncate_identifier(newval, strlen(newval), true);
! 				}
! 				else if (conf->reset_val)
! 				{
! 					/*
! 					 * We could possibly avoid strdup here, but easier to make
! 					 * this case work the same as the normal assignment case.
! 					 */
! 					newval = guc_strdup(elevel, conf->reset_val);
! 					if (newval == NULL)
! 						return false;
! 					source = conf->gen.reset_source;
! 				}
! 				else
! 				{
! 					/* Nothing to reset to, as yet; so do nothing */
! 					break;
! 				}
! 
! 				if (conf->assign_hook)
! 				{
! 					const char *hookresult;
! 
! 					/*
! 					 * If the hook ereports, we have to make sure we free
! 					 * newval, else it will be a permanent memory leak.
! 					 */
! 					hookresult = call_string_assign_hook(conf->assign_hook,
! 														 newval,
! 														 changeVal,
! 														 source);
! 					if (hookresult == NULL)
! 					{
! 						free(newval);
! 						ereport(elevel,
! 								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
! 						 errmsg("invalid value for parameter \"%s\": \"%s\"",
! 								name, value ? value : "")));
! 						return false;
! 					}
! 					else if (hookresult != newval)
! 					{
! 						free(newval);
! 
! 						/*
! 						 * Having to cast away const here is annoying, but the
! 						 * alternative is to declare assign_hooks as returning
! 						 * char*, which would mean they'd have to cast away
! 						 * const, or as both taking and returning char*, which
! 						 * doesn't seem attractive either --- we don't want
! 						 * them to scribble on the passed str.
! 						 */
! 						newval = (char *) hookresult;
! 					}
! 				}
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
  					if (changeVal)
  					{
  						set_string_field(conf, conf->variable, newval);
  						conf->gen.source = source;
  					}
  					if (makeDefault)
  					{
  						GucStack   *stack;
--- 4304,4325 ----
  				struct config_string *conf = (struct config_string *) record;
  				char	   *newval;
  
! 				if (!parse_value(elevel, record, value, &source, changeVal,
! 					(union config_var_value*) &newval))
! 					return false;
  
  				if (changeVal || makeDefault)
  				{
  					/* Save old value to support transaction abort */
  					if (!makeDefault)
  						push_old_value(&conf->gen);
+ 
  					if (changeVal)
  					{
  						set_string_field(conf, conf->variable, newval);
  						conf->gen.source = source;
  					}
+ 
  					if (makeDefault)
  					{
  						GucStack   *stack;
***************
*** 4767,4774 ****
  
  		/* need a tuple descriptor representing a single TEXT column */
  		tupdesc = CreateTemplateTupleDesc(1, false);
! 		TupleDescInitEntry(tupdesc, (AttrNumber) 1, varname,
! 						   TEXTOID, -1, 0);
  	}
  	return tupdesc;
  }
--- 4895,4901 ----
  
  		/* need a tuple descriptor representing a single TEXT column */
  		tupdesc = CreateTemplateTupleDesc(1, false);
! 		TupleDescInitEntry(tupdesc, (AttrNumber) 1, varname, TEXTOID, -1, 0);
  	}
  	return tupdesc;
  }
***************
*** 4860,4866 ****
  		/* send it to dest */
  		do_tup_output(tstate, values);
  
- 		/* clean up */
  		if (values[1] != NULL)
  			pfree(values[1]);
  	}
--- 4987,4992 ----
***************
*** 5314,5319 ****
--- 5440,5448 ----
  static bool
  is_newvalue_equal(struct config_generic *record, const char *newvalue)
  {
+ 	if (!newvalue)
+ 		return false;
+   
  	switch (record->vartype)
  	{
  		case PGC_BOOL:
Index: src/include/utils/guc.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/utils/guc.h,v
retrieving revision 1.73
retrieving revision 1.74
diff -c -r1.73 -r1.74
*** src/include/utils/guc.h	12 Aug 2006 04:12:41 -0000	1.73
--- src/include/utils/guc.h	13 Aug 2006 01:30:17 -0000	1.74
***************
*** 7,13 ****
   * Copyright (c) 2000-2006, PostgreSQL Global Development Group
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
!  * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.73 2006/08/12 04:12:41 momjian Exp $
   *--------------------------------------------------------------------
   */
  #ifndef GUC_H
--- 7,13 ----
   * Copyright (c) 2000-2006, PostgreSQL Global Development Group
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
!  * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.74 2006/08/13 01:30:17 momjian Exp $
   *--------------------------------------------------------------------
   */
  #ifndef GUC_H
***************
*** 193,198 ****
--- 193,201 ----
  extern bool set_config_option(const char *name, const char *value,
  				  GucContext context, GucSource source,
  				  bool isLocal, bool changeVal);
+ extern bool verify_config_option(const char *name, const char *value,
+ 				GucContext context, GucSource source,
+ 				bool *isNewEqual, bool *isContextOK);
  extern char *GetConfigOptionByName(const char *name, const char **varname);
  extern void GetConfigOptionByNum(int varnum, const char **values, bool *noshow);
  extern int	GetNumConfigOptions(void);

Index: src/backend/utils/misc/guc-file.l
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/misc/guc-file.l,v
retrieving revision 1.43
retrieving revision 1.44
diff -c -r1.43 -r1.44
*** src/backend/utils/misc/guc-file.l	13 Aug 2006 01:30:17 -0000	1.43
--- src/backend/utils/misc/guc-file.l	13 Aug 2006 02:22:24 -0000	1.44
***************
*** 4,10 ****
   *
   * Copyright (c) 2000-2006, PostgreSQL Global Development Group
   *
!  * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.43 2006/08/13 01:30:17 momjian Exp $
   */
  
  %{
--- 4,10 ----
   *
   * Copyright (c) 2000-2006, PostgreSQL Global Development Group
   *
!  * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.44 2006/08/13 02:22:24 momjian Exp $
   */
  
  %{
***************
*** 117,122 ****
--- 117,123 ----
  {
  	int			elevel, i;
  	struct name_value_pair *item, *head, *tail;
+ 	char	   *env;
  	bool	   *apply_list = NULL;
  	int			varcount = 0;
  
***************
*** 183,188 ****
--- 184,242 ----
  			set_config_option(item->name, item->value, context,
  							  PGC_S_FILE, false, true);
  
+ 	if (context == PGC_SIGHUP)
+ 	{
+ 	/*
+ 	 * Revert all "untouched" options with reset source PGC_S_FILE to
+ 	 * default/boot value.
+ 	 */
+ 		for (i = 0; i < num_guc_variables; i++)
+ 		{
+ 			struct config_generic *gconf = guc_variables[i];
+ 
+ 			if (gconf->reset_source == PGC_S_FILE &&
+ 				 !(gconf->status & GUC_IN_CONFFILE))
+ 			{
+ 				if (gconf->context == PGC_BACKEND && IsUnderPostmaster)
+ 					; /* Be silent. Does any body want message from each session? */
+ 				else if (gconf->context == PGC_POSTMASTER)
+ 					ereport(elevel,
+ 						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
+ 						errmsg("parameter \"%s\" cannot be changed (commented) after server start; configuration file change ignored",
+ 						gconf->name)));
+ 				else if (set_config_option(gconf->name, NULL, context,
+ 										   PGC_S_FILE, false, true))
+ 				{
+ 					GucStack   *stack;
+ 
+ 					gconf->reset_source = PGC_S_DEFAULT;
+ 
+ 					for (stack = gconf->stack; stack; stack = stack->prev)
+ 						if (stack->source == PGC_S_FILE)
+ 							stack->source = PGC_S_DEFAULT;
+ 
+ 					ereport(elevel,
+ 							(errcode(ERRCODE_SUCCESSFUL_COMPLETION),
+ 							errmsg("configuration option %s returned to default value", gconf->name)));
+ 				}
+ 			}
+ 			gconf->status &= ~GUC_IN_CONFFILE;
+ 		}
+ 
+ 		/*
+ 		 * Revert to environment variable. PGPORT is ignored, because it cannot be
+ 		 * set in running state.
+ 		 */
+ 		env = getenv("PGDATESTYLE");
+ 		if (env != NULL)
+ 			set_config_option("datestyle", env, context,
+ 							  PGC_S_ENV_VAR, false, true);
+ 
+ 		env = getenv("PGCLIENTENCODING");
+ 		if (env != NULL)
+ 			set_config_option("client_encoding", env, context,
+ 							PGC_S_ENV_VAR, false, true);
+ 	}
  
  cleanup_list:
  	if (apply_list)
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v
retrieving revision 1.338
retrieving revision 1.339
diff -c -r1.338 -r1.339
*** src/backend/utils/misc/guc.c	13 Aug 2006 01:30:17 -0000	1.338
--- src/backend/utils/misc/guc.c	13 Aug 2006 02:22:24 -0000	1.339
***************
*** 10,16 ****
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.338 2006/08/13 01:30:17 momjian Exp $
   *
   *--------------------------------------------------------------------
   */
--- 10,16 ----
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.339 2006/08/13 02:22:24 momjian Exp $
   *
   *--------------------------------------------------------------------
   */
***************
*** 2692,2731 ****
  				{
  					struct config_bool *conf = (struct config_bool *) gconf;
  
! 					if (conf->assign_hook)
! 						if (!(*conf->assign_hook) (conf->reset_val, true,
! 												   PGC_S_DEFAULT))
! 							elog(FATAL, "failed to initialize %s to %d",
! 								 conf->gen.name, (int) conf->reset_val);
! 					*conf->variable = conf->reset_val;
  					break;
  				}
  			case PGC_INT:
  				{
  					struct config_int *conf = (struct config_int *) gconf;
  
! 					Assert(conf->reset_val >= conf->min);
! 					Assert(conf->reset_val <= conf->max);
! 					if (conf->assign_hook)
! 						if (!(*conf->assign_hook) (conf->reset_val, true,
! 												   PGC_S_DEFAULT))
! 							elog(FATAL, "failed to initialize %s to %d",
! 								 conf->gen.name, conf->reset_val);
! 					*conf->variable = conf->reset_val;
  					break;
  				}
  			case PGC_REAL:
  				{
  					struct config_real *conf = (struct config_real *) gconf;
  
! 					Assert(conf->reset_val >= conf->min);
! 					Assert(conf->reset_val <= conf->max);
! 					if (conf->assign_hook)
! 						if (!(*conf->assign_hook) (conf->reset_val, true,
! 												   PGC_S_DEFAULT))
! 							elog(FATAL, "failed to initialize %s to %g",
! 								 conf->gen.name, conf->reset_val);
! 					*conf->variable = conf->reset_val;
  					break;
  				}
  			case PGC_STRING:
--- 2692,2731 ----
  				{
  					struct config_bool *conf = (struct config_bool *) gconf;
  
! 					if (conf->assign_hook &&
! 						!(*conf->assign_hook) (conf->boot_val, true,
! 												PGC_S_DEFAULT))
! 						elog(FATAL, "failed to initialize %s to %d",
! 							 conf->gen.name, (int) conf->boot_val);
! 					*conf->variable = conf->reset_val = conf->boot_val;
  					break;
  				}
  			case PGC_INT:
  				{
  					struct config_int *conf = (struct config_int *) gconf;
  
! 					Assert(conf->boot_val >= conf->min);
! 					Assert(conf->boot_val <= conf->max);
! 					if (conf->assign_hook &&
! 						!(*conf->assign_hook) (conf->boot_val, true,
! 												PGC_S_DEFAULT))
! 						elog(FATAL, "failed to initialize %s to %d",
! 							 conf->gen.name, conf->boot_val);
! 					*conf->variable = conf->reset_val = conf->boot_val; 
  					break;
  				}
  			case PGC_REAL:
  				{
  					struct config_real *conf = (struct config_real *) gconf;
  
! 					Assert(conf->boot_val >= conf->min);
! 					Assert(conf->boot_val <= conf->max);
! 					if (conf->assign_hook &&
! 						!(*conf->assign_hook) (conf->boot_val, true,
! 											   PGC_S_DEFAULT))
! 						elog(FATAL, "failed to initialize %s to %g",
! 							 conf->gen.name, conf->boot_val);
! 					*conf->variable = conf->reset_val = conf->boot_val; 
  					break;
  				}
  			case PGC_STRING:
***************
*** 2738,2747 ****
  					conf->tentative_val = NULL;
  
  					if (conf->boot_val == NULL)
- 					{
  						/* Cannot set value yet */
  						break;
- 					}
  
  					str = guc_strdup(FATAL, conf->boot_val);
  					conf->reset_val = str;
--- 2738,2745 ----
***************
*** 2753,2762 ****
  						newstr = (*conf->assign_hook) (str, true,
  													   PGC_S_DEFAULT);
  						if (newstr == NULL)
- 						{
  							elog(FATAL, "failed to initialize %s to \"%s\"",
  								 conf->gen.name, str);
- 						}
  						else if (newstr != str)
  						{
  							free(str);
--- 2751,2758 ----
***************
*** 2796,2807 ****
  	if (env != NULL)
  		SetConfigOption("port", env, PGC_POSTMASTER, PGC_S_ENV_VAR);
  
! 	env = getenv("PGDATESTYLE");
! 	if (env != NULL)
  		SetConfigOption("datestyle", env, PGC_POSTMASTER, PGC_S_ENV_VAR);
  
! 	env = getenv("PGCLIENTENCODING");
! 	if (env != NULL)
  		SetConfigOption("client_encoding", env, PGC_POSTMASTER, PGC_S_ENV_VAR);
  }
  
--- 2792,2801 ----
  	if (env != NULL)
  		SetConfigOption("port", env, PGC_POSTMASTER, PGC_S_ENV_VAR);
  
! 	if ((env = getenv("PGDATESTYLE")) != NULL)
  		SetConfigOption("datestyle", env, PGC_POSTMASTER, PGC_S_ENV_VAR);
  
! 	if ((env = getenv("PGCLIENTENCODING")) != NULL)
  		SetConfigOption("client_encoding", env, PGC_POSTMASTER, PGC_S_ENV_VAR);
  }
  
***************
*** 3178,3184 ****
  	for (i = 0; i < num_guc_variables; i++)
  	{
  		struct config_generic *gconf = guc_variables[i];
! 		int			my_status = gconf->status;
  		GucStack   *stack = gconf->stack;
  		bool		useTentative;
  		bool		changed;
--- 3172,3178 ----
  	for (i = 0; i < num_guc_variables; i++)
  	{
  		struct config_generic *gconf = guc_variables[i];
! 		int			my_status = gconf->status & (~GUC_IN_CONFFILE);
  		GucStack   *stack = gconf->stack;
  		bool		useTentative;
  		bool		changed;
***************
*** 3723,3734 ****
  				}
  				else
  				{
! 					newval = conf->reset_val;
! 					*source = conf->gen.reset_source;
  				}
  
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, *source))
  					{
  						ereport(elevel,
  								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
--- 3717,3738 ----
  				}
  				else
  				{
! 					/*
! 					 * Revert value to default if source is configuration file. It is used when
! 					 * configuration parameter is removed/commented out in the config file. Else
! 					 * RESET or SET TO DEFAULT command is called and reset_val is used.
! 					 */
! 					if (*source == PGC_S_FILE)
! 						newval =  conf->boot_val;
! 					else
! 					{
! 						newval = conf->reset_val;
! 						*source = conf->gen.reset_source;
! 					}
  				}
  
! 				if (conf->assign_hook &&
! 					!(*conf->assign_hook) (newval, changeVal, *source))
  					{
  						ereport(elevel,
  								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
***************
*** 3767,3774 ****
  				}
  				else
  				{
! 					newval = conf->reset_val;
! 					*source = conf->gen.reset_source;
  				}
  
  				if (conf->assign_hook)
--- 3771,3788 ----
  				}
  				else
  				{
! 					/*
! 					 * Revert value to default if source is configuration file. It is used when
! 					 * configuration parameter is removed/commented out in the config file. Else
! 					 * RESET or SET TO DEFAULT command is called and reset_val is used.
! 					 */
! 					if (*source == PGC_S_FILE)
! 						newval =  conf->boot_val;
! 					else
! 					{
! 						newval = conf->reset_val;
! 						*source = conf->gen.reset_source;
! 					}
  				}
  
  				if (conf->assign_hook)
***************
*** 3811,3822 ****
  				}
  				else
  				{
! 					newval = conf->reset_val;
! 					*source = conf->gen.reset_source;
  				}
  
! 				if (conf->assign_hook)
! 					if (!(*conf->assign_hook) (newval, changeVal, *source))
  					{
  						ereport(elevel,
  								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
--- 3825,3846 ----
  				}
  				else
  				{
! 					/*
! 					 * Revert value to default if source is configuration file. It is used when
! 					 * configuration parameter is removed/commented out in the config file. Else
! 					 * RESET or SET TO DEFAULT command is called and reset_val is used.
! 					 */
! 					if (*source == PGC_S_FILE)
! 						newval =  conf->boot_val;
! 					else
! 					{
! 						newval = conf->reset_val;
! 						*source = conf->gen.reset_source;
! 					}
  				}
  
! 				if (conf->assign_hook &&
! 					!(*conf->assign_hook) (newval, changeVal, *source))
  					{
  						ereport(elevel,
  								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
***************
*** 3845,3850 ****
--- 3869,3886 ----
  					if (conf->gen.flags & GUC_IS_NAME)
  						truncate_identifier(newval, strlen(newval), true);
  				}
+ 				else if (*source == PGC_S_FILE)
+ 				{
+ 					/* Revert value to default when item is removed from config file. */
+ 					if (conf->boot_val != NULL)
+ 					{
+ 						newval = guc_strdup(elevel, conf->boot_val);
+ 						if (newval == NULL)
+ 							return false;
+ 					}
+ 					else
+ 						return false;
+ 				} 
  				else if (conf->reset_val)
  				{
  					/*
***************
*** 3856,3865 ****
  					*source = conf->gen.reset_source;
  				}
  				else
- 				{
  					/* Nothing to reset to, as yet; so do nothing */
  					break;
- 				}
  
  				if (conf->assign_hook)
  				{
--- 3892,3899 ----
***************
*** 4047,4052 ****
--- 4081,4093 ----
  
  	if (parse_value(elevel, record, value, &source, false, NULL))
  	{
+ 		/*
+ 		 * Mark record like presented in the config file. Be carefull if
+ 		 * you use this function for another purpose than config file 
+ 		 * verification. It causes confusion configfile parser.
+ 		 */
+ 		record->status |= GUC_IN_CONFFILE;
+ 
  		if (isNewEqual != NULL)
  			*isNewEqual = is_newvalue_equal(record, value);
  		if (isContextOK != NULL)
***************
*** 4109,4115 ****
  	 * Should we set reset/stacked values?	(If so, the behavior is not
  	 * transactional.)
  	 */
! 	makeDefault = changeVal && (source <= PGC_S_OVERRIDE) && (value != NULL);
  
  	/*
  	 * Ignore attempted set if overridden by previously processed setting.
--- 4150,4157 ----
  	 * Should we set reset/stacked values?	(If so, the behavior is not
  	 * transactional.)
  	 */
! 	makeDefault = changeVal && (source <= PGC_S_OVERRIDE) &&
! 					(value != NULL || source == PGC_S_FILE);
  
  	/*
  	 * Ignore attempted set if overridden by previously processed setting.
Index: src/include/utils/guc_tables.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/utils/guc_tables.h,v
retrieving revision 1.26
retrieving revision 1.27
diff -c -r1.26 -r1.27
*** src/include/utils/guc_tables.h	12 Aug 2006 04:11:50 -0000	1.26
--- src/include/utils/guc_tables.h	13 Aug 2006 02:22:24 -0000	1.27
***************
*** 7,13 ****
   *
   * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
   *
!  *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.26 2006/08/12 04:11:50 momjian Exp $
   *
   *-------------------------------------------------------------------------
   */
--- 7,13 ----
   *
   * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
   *
!  *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.27 2006/08/13 02:22:24 momjian Exp $
   *
   *-------------------------------------------------------------------------
   */
***************
*** 143,149 ****
  #define GUC_HAVE_TENTATIVE	0x0001		/* tentative value is defined */
  #define GUC_HAVE_LOCAL		0x0002		/* a SET LOCAL has been executed */
  #define GUC_HAVE_STACK		0x0004		/* we have stacked prior value(s) */
! 
  
  /* GUC records for specific variable types */
  
--- 143,150 ----
  #define GUC_HAVE_TENTATIVE	0x0001		/* tentative value is defined */
  #define GUC_HAVE_LOCAL		0x0002		/* a SET LOCAL has been executed */
  #define GUC_HAVE_STACK		0x0004		/* we have stacked prior value(s) */
! #define GUC_IN_CONFFILE		0x0008		/* value shows up in the configuration
! 										   file (is not commented) */
  
  /* GUC records for specific variable types */
  
***************
*** 153,163 ****
  	/* these fields must be set correctly in initial value: */
  	/* (all but reset_val are constants) */
  	bool	   *variable;
! 	bool		reset_val;
  	GucBoolAssignHook assign_hook;
  	GucShowHook show_hook;
  	/* variable fields, initialized at runtime: */
  	bool		tentative_val;
  };
  
  struct config_int
--- 154,165 ----
  	/* these fields must be set correctly in initial value: */
  	/* (all but reset_val are constants) */
  	bool	   *variable;
! 	bool		boot_val;
  	GucBoolAssignHook assign_hook;
  	GucShowHook show_hook;
  	/* variable fields, initialized at runtime: */
  	bool		tentative_val;
+ 	bool		reset_val;
  };
  
  struct config_int
***************
*** 166,178 ****
  	/* these fields must be set correctly in initial value: */
  	/* (all but reset_val are constants) */
  	int		   *variable;
! 	int			reset_val;
  	int			min;
  	int			max;
  	GucIntAssignHook assign_hook;
  	GucShowHook show_hook;
  	/* variable fields, initialized at runtime: */
  	int			tentative_val;
  };
  
  struct config_real
--- 168,181 ----
  	/* these fields must be set correctly in initial value: */
  	/* (all but reset_val are constants) */
  	int		   *variable;
! 	int			boot_val;
  	int			min;
  	int			max;
  	GucIntAssignHook assign_hook;
  	GucShowHook show_hook;
  	/* variable fields, initialized at runtime: */
  	int			tentative_val;
+ 	int			reset_val;
  };
  
  struct config_real
***************
*** 181,193 ****
  	/* these fields must be set correctly in initial value: */
  	/* (all but reset_val are constants) */
  	double	   *variable;
! 	double		reset_val;
  	double		min;
  	double		max;
  	GucRealAssignHook assign_hook;
  	GucShowHook show_hook;
  	/* variable fields, initialized at runtime: */
  	double		tentative_val;
  };
  
  struct config_string
--- 184,197 ----
  	/* these fields must be set correctly in initial value: */
  	/* (all but reset_val are constants) */
  	double	   *variable;
! 	double		boot_val;
  	double		min;
  	double		max;
  	GucRealAssignHook assign_hook;
  	GucShowHook show_hook;
  	/* variable fields, initialized at runtime: */
  	double		tentative_val;
+ 	double		reset_val;
  };
  
  struct config_string

Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v
retrieving revision 1.339
retrieving revision 1.340
diff -c -r1.339 -r1.340
*** src/backend/utils/misc/guc.c	13 Aug 2006 02:22:24 -0000	1.339
--- src/backend/utils/misc/guc.c	13 Aug 2006 15:37:02 -0000	1.340
***************
*** 10,16 ****
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.339 2006/08/13 02:22:24 momjian Exp $
   *
   *--------------------------------------------------------------------
   */
--- 10,16 ----
   * Written by Peter Eisentraut <peter_e@gmx.net>.
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.340 2006/08/13 15:37:02 momjian Exp $
   *
   *--------------------------------------------------------------------
   */
***************
*** 4082,4090 ****
  	if (parse_value(elevel, record, value, &source, false, NULL))
  	{
  		/*
! 		 * Mark record like presented in the config file. Be carefull if
  		 * you use this function for another purpose than config file 
! 		 * verification. It causes confusion configfile parser.
  		 */
  		record->status |= GUC_IN_CONFFILE;
  
--- 4082,4090 ----
  	if (parse_value(elevel, record, value, &source, false, NULL))
  	{
  		/*
! 		 * Mark record as present in the config file. Be carefull if
  		 * you use this function for another purpose than config file 
! 		 * verification. It causes confusion in the config file parser.
  		 */
  		record->status |= GUC_IN_CONFFILE;
  
***************
*** 5512,5518 ****
  		{
  			struct config_string *conf = (struct config_string *) record;
  
! 			return strcmp(*conf->variable, newvalue) == 0;
  		}
  	}
  
--- 5512,5521 ----
  		{
  			struct config_string *conf = (struct config_string *) record;
  
! 			if (!*conf->variable)	/* custom variable with no value yet */
! 				return false;
! 			else
! 				return strcmp(*conf->variable, newvalue) == 0;
  		}
  	}