guc.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,468 行 · 第 1/5 页

					conf->gen.source = conf->gen.reset_source;
					conf->gen.tentative_source = conf->gen.reset_source;
					conf->gen.status |= GUC_HAVE_TENTATIVE;
					guc_dirty = true;
					break;
				}
			case PGC_REAL:
				{
					struct config_real *conf = (struct config_real *) gconf;

					if (conf->assign_hook)
						if (!(*conf->assign_hook) (conf->reset_val, true, true))
							elog(ERROR, "failed to reset %s", conf->gen.name);
					*conf->variable = conf->reset_val;
					conf->tentative_val = conf->reset_val;
					conf->gen.source = conf->gen.reset_source;
					conf->gen.tentative_source = conf->gen.reset_source;
					conf->gen.status |= GUC_HAVE_TENTATIVE;
					guc_dirty = true;
					break;
				}
			case PGC_STRING:
				{
					struct config_string *conf = (struct config_string *) gconf;
					char	   *str;

					if (conf->reset_val == NULL)
					{
						/* Nothing to reset to, as yet; so do nothing */
						break;
					}

					/* We need not strdup here */
					str = conf->reset_val;

					if (conf->assign_hook)
					{
						const char *newstr;

						newstr = (*conf->assign_hook) (str, true, true);
						if (newstr == NULL)
							elog(ERROR, "failed to reset %s", conf->gen.name);
						else if (newstr != str)
						{
							/*
							 * See notes in set_config_option about
							 * casting
							 */
							str = (char *) newstr;
						}
					}

					SET_STRING_VARIABLE(conf, str);
					SET_STRING_TENTATIVE_VAL(conf, str);
					conf->gen.source = conf->gen.reset_source;
					conf->gen.tentative_source = conf->gen.reset_source;
					conf->gen.status |= GUC_HAVE_TENTATIVE;
					guc_dirty = true;
					break;
				}
		}

		if (gconf->flags & GUC_REPORT)
			ReportGUCOption(gconf);
	}
}


/*
 * Do GUC processing at transaction commit or abort.
 */
void
AtEOXact_GUC(bool isCommit)
{
	int			i;

	/* Quick exit if nothing's changed in this transaction */
	if (!guc_dirty)
		return;

	/* Prevent memory leak if ereport during an assign_hook */
	if (guc_string_workspace)
	{
		free(guc_string_workspace);
		guc_string_workspace = NULL;
	}

	for (i = 0; i < num_guc_variables; i++)
	{
		struct config_generic *gconf = guc_variables[i];
		bool		changed;

		/* Skip if nothing's happened to this var in this transaction */
		if (gconf->status == 0)
			continue;

		changed = false;

		switch (gconf->vartype)
		{
			case PGC_BOOL:
				{
					struct config_bool *conf = (struct config_bool *) gconf;

					if (isCommit && (conf->gen.status & GUC_HAVE_TENTATIVE))
					{
						conf->session_val = conf->tentative_val;
						conf->gen.session_source = conf->gen.tentative_source;
					}

					if (*conf->variable != conf->session_val)
					{
						if (conf->assign_hook)
							if (!(*conf->assign_hook) (conf->session_val,
													   true, false))
								elog(LOG, "failed to commit %s",
									 conf->gen.name);
						*conf->variable = conf->session_val;
						changed = true;
					}
					conf->gen.source = conf->gen.session_source;
					conf->gen.status = 0;
					break;
				}
			case PGC_INT:
				{
					struct config_int *conf = (struct config_int *) gconf;

					if (isCommit && (conf->gen.status & GUC_HAVE_TENTATIVE))
					{
						conf->session_val = conf->tentative_val;
						conf->gen.session_source = conf->gen.tentative_source;
					}

					if (*conf->variable != conf->session_val)
					{
						if (conf->assign_hook)
							if (!(*conf->assign_hook) (conf->session_val,
													   true, false))
								elog(LOG, "failed to commit %s",
									 conf->gen.name);
						*conf->variable = conf->session_val;
						changed = true;
					}
					conf->gen.source = conf->gen.session_source;
					conf->gen.status = 0;
					break;
				}
			case PGC_REAL:
				{
					struct config_real *conf = (struct config_real *) gconf;

					if (isCommit && (conf->gen.status & GUC_HAVE_TENTATIVE))
					{
						conf->session_val = conf->tentative_val;
						conf->gen.session_source = conf->gen.tentative_source;
					}

					if (*conf->variable != conf->session_val)
					{
						if (conf->assign_hook)
							if (!(*conf->assign_hook) (conf->session_val,
													   true, false))
								elog(LOG, "failed to commit %s",
									 conf->gen.name);
						*conf->variable = conf->session_val;
						changed = true;
					}
					conf->gen.source = conf->gen.session_source;
					conf->gen.status = 0;
					break;
				}
			case PGC_STRING:
				{
					struct config_string *conf = (struct config_string *) gconf;

					if (isCommit && (conf->gen.status & GUC_HAVE_TENTATIVE))
					{
						SET_STRING_SESSION_VAL(conf, conf->tentative_val);
						conf->gen.session_source = conf->gen.tentative_source;
						conf->tentative_val = NULL;		/* transfer ownership */
					}
					else
						SET_STRING_TENTATIVE_VAL(conf, NULL);

					if (*conf->variable != conf->session_val)
					{
						char	   *str = conf->session_val;

						if (conf->assign_hook)
						{
							const char *newstr;

							newstr = (*conf->assign_hook) (str, true, false);
							if (newstr == NULL)
								elog(LOG, "failed to commit %s",
									 conf->gen.name);
							else if (newstr != str)
							{
								/*
								 * See notes in set_config_option about
								 * casting
								 */
								str = (char *) newstr;
								SET_STRING_SESSION_VAL(conf, str);
							}
						}

						SET_STRING_VARIABLE(conf, str);
						changed = true;
					}
					conf->gen.source = conf->gen.session_source;
					conf->gen.status = 0;
					break;
				}
		}

		if (changed && (gconf->flags & GUC_REPORT))
			ReportGUCOption(gconf);
	}

	guc_dirty = false;
}


/*
 * Start up automatic reporting of changes to variables marked GUC_REPORT.
 * This is executed at completion of backend startup.
 */
void
BeginReportingGUCOptions(void)
{
	int			i;

	/*
	 * Don't do anything unless talking to an interactive frontend of
	 * protocol 3.0 or later.
	 */
	if (whereToSendOutput != Remote ||
		PG_PROTOCOL_MAJOR(FrontendProtocol) < 3)
		return;

	reporting_enabled = true;

	/* Transmit initial values of interesting variables */
	for (i = 0; i < num_guc_variables; i++)
	{
		struct config_generic *conf = guc_variables[i];

		if (conf->flags & GUC_REPORT)
			ReportGUCOption(conf);
	}
}

/*
 * ReportGUCOption: if appropriate, transmit option value to frontend
 */
static void
ReportGUCOption(struct config_generic * record)
{
	if (reporting_enabled && (record->flags & GUC_REPORT))
	{
		char	   *val = _ShowOption(record);
		StringInfoData msgbuf;

		pq_beginmessage(&msgbuf, 'S');
		pq_sendstring(&msgbuf, record->name);
		pq_sendstring(&msgbuf, val);
		pq_endmessage(&msgbuf);

		pfree(val);
	}
}


/*
 * Try to interpret value as boolean value.  Valid values are: true,
 * false, yes, no, on, off, 1, 0.  If the string parses okay, return
 * true, else false.  If result is not NULL, return the parsing result
 * there.
 */
static bool
parse_bool(const char *value, bool *result)
{
	size_t		len = strlen(value);

	if (strncasecmp(value, "true", len) == 0)
	{
		if (result)
			*result = true;
	}
	else if (strncasecmp(value, "false", len) == 0)
	{
		if (result)
			*result = false;
	}

	else if (strncasecmp(value, "yes", len) == 0)
	{
		if (result)
			*result = true;
	}
	else if (strncasecmp(value, "no", len) == 0)
	{
		if (result)
			*result = false;
	}

	else if (strcasecmp(value, "on") == 0)
	{
		if (result)
			*result = true;
	}
	else if (strcasecmp(value, "off") == 0)
	{
		if (result)
			*result = false;
	}

	else if (strcasecmp(value, "1") == 0)
	{
		if (result)
			*result = true;
	}
	else if (strcasecmp(value, "0") == 0)
	{
		if (result)
			*result = false;
	}

	else
		return false;
	return true;
}



/*
 * Try to parse value as an integer.  The accepted formats are the
 * usual decimal, octal, or hexadecimal formats.  If the string parses
 * okay, return true, else false.  If result is not NULL, return the
 * value there.
 */
static bool
parse_int(const char *value, int *result)
{
	long		val;
	char	   *endptr;

	errno = 0;
	val = strtol(value, &endptr, 0);
	if (endptr == value || *endptr != '\0' || errno == ERANGE
#ifdef HAVE_LONG_INT_64
	/* if long > 32 bits, check for overflow of int4 */
		|| val != (long) ((int32) val)
#endif
		)
		return false;
	if (result)
		*result = (int) val;
	return true;
}



/*
 * Try to parse value as a floating point constant in the usual
 * format.	If the value parsed okay return true, else false.  If
 * result is not NULL, return the semantic value there.
 */
static bool
parse_real(const char *value, double *result)
{
	double		val;
	char	   *endptr;

	errno = 0;
	val = strtod(value, &endptr);
	if (endptr == value || *endptr != '\0' || errno == ERANGE)
		return false;
	if (result)
		*result = val;
	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		interactive;
	bool		makeDefault;
	bool		changeVal_orig;

	if (context == PGC_SIGHUP || source == PGC_S_DEFAULT)
		elevel = DEBUG2;
	else if (source == PGC_S_DATABASE || source == PGC_S_USER)
		elevel = INFO;
	else
		elevel = ERROR;

	record = find_option(name);
	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)
				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;
		case PGC_SIGHUP:
			if (context != PGC_SIGHUP && context != PGC_POSTMASTER)
			{
				ereport(elevel,
						(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
						 errmsg("parameter \"%s\" cannot be changed now",
								name)));
				return false;
			}

			/*
			 * 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.
			 */
			break;
		case PGC_BACKEND:
			if (context == PGC_SIGHUP)
			{
				/*
				 * If a PGC_BACKEND parameter is changed in the config
				 * file, we want to accept the new value in the postmaster
				 * (w