guc.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

		NULL, assign_session_authorization, show_session_authorization
	},

	{
		{"log_destination", PGC_SIGHUP, LOGGING_WHERE,
			gettext_noop("Sets the destination for server log output."),
			gettext_noop("Valid values are combinations of \"stderr\", \"syslog\", "
						 "and \"eventlog\", depending on the platform."),
			GUC_LIST_INPUT
		},
		&log_destination_string,
		"stderr", assign_log_destination, NULL
	},
	{
		{"log_directory", PGC_SIGHUP, LOGGING_WHERE,
			gettext_noop("Sets the destination directory for log files."),
			gettext_noop("May be specified as relative to the data directory "
						 "or as absolute path."),
			GUC_SUPERUSER_ONLY
		},
		&Log_directory,
		"pg_log", assign_canonical_path, NULL
	},
	{
		{"log_filename", PGC_SIGHUP, LOGGING_WHERE,
			gettext_noop("Sets the file name pattern for log files."),
			NULL,
			GUC_SUPERUSER_ONLY
		},
		&Log_filename,
		"postgresql-%Y-%m-%d_%H%M%S.log", NULL, NULL
	},

#ifdef HAVE_SYSLOG
	{
		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
			gettext_noop("Valid values are LOCAL0, LOCAL1, LOCAL2, LOCAL3, "
						 "LOCAL4, LOCAL5, LOCAL6, LOCAL7.")
		},
		&syslog_facility_str,
		"LOCAL0", assign_syslog_facility, NULL
	},
	{
		{"syslog_ident", PGC_SIGHUP, LOGGING_WHERE,
			gettext_noop("Sets the program name used to identify PostgreSQL "
						 "messages in syslog."),
			NULL
		},
		&syslog_ident_str,
		"postgres", assign_syslog_ident, NULL
	},
#endif

	{
		{"TimeZone", PGC_USERSET, CLIENT_CONN_LOCALE,
			gettext_noop("Sets the time zone for displaying and interpreting time stamps."),
			NULL,
			GUC_REPORT
		},
		&timezone_string,
		"UNKNOWN", assign_timezone, show_timezone
	},

	{
		{"transaction_isolation", PGC_USERSET, CLIENT_CONN_STATEMENT,
			gettext_noop("Sets the current transaction's isolation level."),
			NULL,
			GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
		},
		&XactIsoLevel_string,
		NULL, assign_XactIsoLevel, show_XactIsoLevel
	},

	{
		{"unix_socket_group", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
			gettext_noop("Sets the owning group of the Unix-domain socket."),
			gettext_noop("(The owning user of the socket is always the user "
						 "that starts the server.)")
		},
		&Unix_socket_group,
		"", NULL, NULL
	},

	{
		{"unix_socket_directory", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
			gettext_noop("Sets the directory where the Unix-domain socket will be created."),
			NULL,
			GUC_SUPERUSER_ONLY
		},
		&UnixSocketDir,
		"", assign_canonical_path, NULL
	},

	{
		{"listen_addresses", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
			gettext_noop("Sets the host name or IP address(es) to listen to."),
			NULL,
			GUC_LIST_INPUT
		},
		&ListenAddresses,
		"localhost", NULL, NULL
	},

	{
		{"wal_sync_method", PGC_SIGHUP, WAL_SETTINGS,
			gettext_noop("Selects the method used for forcing WAL updates out to disk."),
			NULL
		},
		&XLOG_sync_method,
		XLOG_sync_method_default, assign_xlog_sync_method, NULL
	},

	{
		{"custom_variable_classes", PGC_SIGHUP, CUSTOM_OPTIONS,
			gettext_noop("Sets the list of known custom variable classes."),
			NULL,
			GUC_LIST_INPUT | GUC_LIST_QUOTE
		},
		&custom_variable_classes,
		NULL, assign_custom_variable_classes, NULL
	},

	{
		{"data_directory", PGC_POSTMASTER, FILE_LOCATIONS,
			gettext_noop("Sets the server's data directory."),
			NULL,
			GUC_SUPERUSER_ONLY
		},
		&data_directory,
		NULL, NULL, NULL
	},

	{
		{"config_file", PGC_POSTMASTER, FILE_LOCATIONS,
			gettext_noop("Sets the server's main configuration file."),
			NULL,
			GUC_DISALLOW_IN_FILE | GUC_SUPERUSER_ONLY
		},
		&ConfigFileName,
		NULL, NULL, NULL
	},

	{
		{"hba_file", PGC_POSTMASTER, FILE_LOCATIONS,
			gettext_noop("Sets the server's \"hba\" configuration file"),
			NULL,
			GUC_SUPERUSER_ONLY
		},
		&HbaFileName,
		NULL, NULL, NULL
	},

	{
		{"ident_file", PGC_POSTMASTER, FILE_LOCATIONS,
			gettext_noop("Sets the server's \"ident\" configuration file"),
			NULL,
			GUC_SUPERUSER_ONLY
		},
		&IdentFileName,
		NULL, NULL, NULL
	},

	{
		{"external_pid_file", PGC_POSTMASTER, FILE_LOCATIONS,
			gettext_noop("Writes the postmaster PID to the specified file."),
			NULL,
			GUC_SUPERUSER_ONLY
		},
		&external_pid_file,
		NULL, assign_canonical_path, NULL
	},

	/* End-of-list marker */
	{
		{NULL, 0, 0, NULL, NULL}, NULL, NULL, NULL, NULL
	}
};


/******** end of options list ********/


/*
 * To allow continued support of obsolete names for GUC variables, we apply
 * the following mappings to any unrecognized name.  Note that an old name
 * should be mapped to a new one only if the new variable has very similar
 * semantics to the old.
 */
static const char *const map_old_guc_names[] = {
	"sort_mem", "work_mem",
	"vacuum_mem", "maintenance_work_mem",
	NULL
};


/*
 * Actual lookup of variables is done through this single, sorted array.
 */
static struct config_generic **guc_variables;

/* Current number of variables contained in the vector */
static int	num_guc_variables;

/* Vector capacity */
static int	size_guc_variables;


static bool guc_dirty;			/* TRUE if need to do commit/abort work */

static bool reporting_enabled;	/* TRUE to enable GUC_REPORT */


static int	guc_var_compare(const void *a, const void *b);
static int	guc_name_compare(const char *namea, const char *nameb);
static void push_old_value(struct config_generic * gconf);
static void ReportGUCOption(struct config_generic * record);
static void ShowGUCConfigOption(const char *name, DestReceiver *dest);
static void ShowAllGUCConfig(DestReceiver *dest);
static char *_ShowOption(struct config_generic * record);


/*
 * Some infrastructure for checking malloc/strdup/realloc calls
 */
static void *
guc_malloc(int elevel, size_t size)
{
	void	   *data;

	data = malloc(size);
	if (data == NULL)
		ereport(elevel,
				(errcode(ERRCODE_OUT_OF_MEMORY),
				 errmsg("out of memory")));
	return data;
}

static void *
guc_realloc(int elevel, void *old, size_t size)
{
	void	   *data;

	data = realloc(old, size);
	if (data == NULL)
		ereport(elevel,
				(errcode(ERRCODE_OUT_OF_MEMORY),
				 errmsg("out of memory")));
	return data;
}

static char *
guc_strdup(int elevel, const char *src)
{
	char	   *data;

	data = strdup(src);
	if (data == NULL)
		ereport(elevel,
				(errcode(ERRCODE_OUT_OF_MEMORY),
				 errmsg("out of memory")));
	return data;
}


/*
 * Support for assigning to a field of a string GUC item.  Free the prior
 * value if it's not referenced anywhere else in the item (including stacked
 * states).
 */
static void
set_string_field(struct config_string * conf, char **field, char *newval)
{
	char	   *oldval = *field;
	GucStack   *stack;

	/* Do the assignment */
	*field = newval;

	/* Exit if any duplicate references, or if old value was NULL anyway */
	if (oldval == NULL ||
		oldval == *(conf->variable) ||
		oldval == conf->reset_val ||
		oldval == conf->tentative_val)
		return;
	for (stack = conf->gen.stack; stack; stack = stack->prev)
	{
		if (oldval == stack->tentative_val.stringval ||
			oldval == stack->value.stringval)
			return;
	}

	/* Not used anymore, so free it */
	free(oldval);
}

/*
 * Detect whether strval is referenced anywhere in a GUC string item
 */
static bool
string_field_used(struct config_string * conf, char *strval)
{
	GucStack   *stack;

	if (strval == *(conf->variable) ||
		strval == conf->reset_val ||
		strval == conf->tentative_val)
		return true;
	for (stack = conf->gen.stack; stack; stack = stack->prev)
	{
		if (strval == stack->tentative_val.stringval ||
			strval == stack->value.stringval)
			return true;
	}
	return false;
}


struct config_generic **
get_guc_variables(void)
{
	return guc_variables;
}


/*
 * Build the sorted array.	This is split out so that it could be
 * re-executed after startup (eg, we could allow loadable modules to
 * add vars, and then we'd need to re-sort).
 */
void
build_guc_variables(void)
{
	int			size_vars;
	int			num_vars = 0;
	struct config_generic **guc_vars;
	int			i;

	for (i = 0; ConfigureNamesBool[i].gen.name; i++)
	{
		struct config_bool *conf = &ConfigureNamesBool[i];

		/* Rather than requiring vartype to be filled in by hand, do this: */
		conf->gen.vartype = PGC_BOOL;
		num_vars++;
	}

	for (i = 0; ConfigureNamesInt[i].gen.name; i++)
	{
		struct config_int *conf = &ConfigureNamesInt[i];

		conf->gen.vartype = PGC_INT;
		num_vars++;
	}

	for (i = 0; ConfigureNamesReal[i].gen.name; i++)
	{
		struct config_real *conf = &ConfigureNamesReal[i];

		conf->gen.vartype = PGC_REAL;
		num_vars++;
	}

	for (i = 0; ConfigureNamesString[i].gen.name; i++)
	{
		struct config_string *conf = &ConfigureNamesString[i];

		conf->gen.vartype = PGC_STRING;
		num_vars++;
	}

	/*
	 * Create table with 20% slack
	 */
	size_vars = num_vars + num_vars / 4;

	guc_vars = (struct config_generic **)
		guc_malloc(FATAL, size_vars * sizeof(struct config_generic *));

	num_vars = 0;

	for (i = 0; ConfigureNamesBool[i].gen.name; i++)
		guc_vars[num_vars++] = &ConfigureNamesBool[i].gen;

	for (i = 0; ConfigureNamesInt[i].gen.name; i++)
		guc_vars[num_vars++] = &ConfigureNamesInt[i].gen;

	for (i = 0; ConfigureNamesReal[i].gen.name; i++)
		guc_vars[num_vars++] = &ConfigureNamesReal[i].gen;

	for (i = 0; ConfigureNamesString[i].gen.name; i++)
		guc_vars[num_vars++] = &ConfigureNamesString[i].gen;

	if (guc_variables)
		free(guc_variables);
	guc_variables = guc_vars;
	num_guc_variables = num_vars;
	size_guc_variables = size_vars;
	qsort((void *) guc_variables, num_guc_variables,
		  sizeof(struct config_generic *), guc_var_compare);
}

static bool
is_custom_class(const char *name, int dotPos)
{
	/*
	 * assign_custom_variable_classes() has made sure no empty identifiers or
	 * whitespace exists in the variable
	 */
	bool		result = false;
	const char *ccs = GetConfigOption("custom_variable_classes");

	if (ccs != NULL)
	{
		const char *start = ccs;

		for (;; ++ccs)
		{
			int			c = *ccs;

			if (c == 0 || c == ',')
			{
				if (dotPos == ccs - start && strncmp(start, name, dotPos) == 0)
				{
					result = true;
					break;
				}
				if (c == 0)
					break;
				start = ccs + 1;
			}
		}
	}
	return result;
}

/*
 * Add a new GUC variable to the list of known variables. The
 * list is expanded if needed.
 */
static bool
add_guc_variable(struct config_generic * var, int elevel)
{
	if (num_guc_variables + 1 >= size_guc_variables)
	{
		/*
		 * Increase the vector by 25%
		 */
		int			size_vars = size_guc_variables + size_guc_variables / 4;
		struct config_generic **guc_vars;

		if (size_vars == 0)
		{
			size_vars = 100;
			guc_vars = (struct config_generic **)
				guc_malloc(elevel, size_vars * sizeof(struct config_generic *));
		}
		else
		{
			guc_vars = (struct config_generic **)
				guc_realloc(elevel, guc_variables, size_vars * sizeof(struct config_generic *));
		}

		if (guc_vars == NULL)
			return false;		/* out of memory */

		guc_variables = guc_vars;
		size_guc_variables = size_vars;
	}
	guc_variables[num_guc_variables++] = var;
	qsort((void *) guc_variables, num_guc_variables,
		  sizeof(struct config_generic *), guc_var_compare);
	return true;
}

/*
 * Create and add a placeholder variable. It's presumed to belong
 * to a valid custom variable class at this point.
 */
static struct config_string *
add_placeholder_variable(const char *name, int elevel)
{
	size_t		sz = sizeof(struct config_string) + sizeof(char *);
	struct config_string *var;
	struct config_generic *gen;

	var = (struct config_string *) guc_malloc(elevel, sz);
	if (v