variable.c

来自「PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统」· C语言 代码 · 共 830 行 · 第 1/2 页

/*
 * show_timezone: GUC show_hook for timezone
 */
const char *
show_timezone(void)
{
	const char *tzn;

	if (HasCTZSet)
	{
		Interval	interval;

		interval.month = 0;
		interval.day = 0;
#ifdef HAVE_INT64_TIMESTAMP
		interval.time = -(CTimeZone * USECS_PER_SEC);
#else
		interval.time = -CTimeZone;
#endif

		tzn = DatumGetCString(DirectFunctionCall1(interval_out,
											  IntervalPGetDatum(&interval)));
	}
	else
		tzn = pg_get_timezone_name(global_timezone);

	if (tzn != NULL)
		return tzn;

	return "unknown";
}


/*
 * SET TRANSACTION ISOLATION LEVEL
 */

const char *
assign_XactIsoLevel(const char *value, bool doit, GucSource source)
{
	if (SerializableSnapshot != NULL)
	{
		if (source >= PGC_S_INTERACTIVE)
			ereport(ERROR,
					(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
					 errmsg("SET TRANSACTION ISOLATION LEVEL must be called before any query")));
		/* source == PGC_S_OVERRIDE means do it anyway, eg at xact abort */
		else if (source != PGC_S_OVERRIDE)
			return NULL;
	}
	if (IsSubTransaction())
	{
		if (source >= PGC_S_INTERACTIVE)
			ereport(ERROR,
					(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
					 errmsg("SET TRANSACTION ISOLATION LEVEL must not be called in a subtransaction")));
		/* source == PGC_S_OVERRIDE means do it anyway, eg at xact abort */
		else if (source != PGC_S_OVERRIDE)
			return NULL;
	}

	if (strcmp(value, "serializable") == 0)
	{
		if (doit)
			XactIsoLevel = XACT_SERIALIZABLE;
	}
	else if (strcmp(value, "repeatable read") == 0)
	{
		if (doit)
			XactIsoLevel = XACT_REPEATABLE_READ;
	}
	else if (strcmp(value, "read committed") == 0)
	{
		if (doit)
			XactIsoLevel = XACT_READ_COMMITTED;
	}
	else if (strcmp(value, "read uncommitted") == 0)
	{
		if (doit)
			XactIsoLevel = XACT_READ_UNCOMMITTED;
	}
	else if (strcmp(value, "default") == 0)
	{
		if (doit)
			XactIsoLevel = DefaultXactIsoLevel;
	}
	else
		return NULL;

	return value;
}

const char *
show_XactIsoLevel(void)
{
	switch (XactIsoLevel)
	{
		case XACT_READ_UNCOMMITTED:
			return "read uncommitted";
		case XACT_READ_COMMITTED:
			return "read committed";
		case XACT_REPEATABLE_READ:
			return "repeatable read";
		case XACT_SERIALIZABLE:
			return "serializable";
		default:
			return "bogus";
	}
}


/*
 * Random number seed
 */

bool
assign_random_seed(double value, bool doit, GucSource source)
{
	/* Can't really roll back on error, so ignore non-interactive setting */
	if (doit && source >= PGC_S_INTERACTIVE)
		DirectFunctionCall1(setseed, Float8GetDatum(value));
	return true;
}

const char *
show_random_seed(void)
{
	return "unavailable";
}


/*
 * encoding handling functions
 */

const char *
assign_client_encoding(const char *value, bool doit, GucSource source)
{
	int			encoding;

	encoding = pg_valid_client_encoding(value);
	if (encoding < 0)
		return NULL;

	/*
	 * Note: if we are in startup phase then SetClientEncoding may not be able
	 * to really set the encoding.	In this case we will assume that the
	 * encoding is okay, and InitializeClientEncoding() will fix things once
	 * initialization is complete.
	 */
	if (SetClientEncoding(encoding, doit) < 0)
	{
		if (source >= PGC_S_INTERACTIVE)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("conversion between %s and %s is not supported",
							value, GetDatabaseEncodingName())));
		return NULL;
	}
	return value;
}


/*
 * SET SESSION AUTHORIZATION
 *
 * When resetting session auth after an error, we can't expect to do catalog
 * lookups.  Hence, the stored form of the value must provide a numeric oid
 * that can be re-used directly.  We store the string in the form of
 * NAMEDATALEN 'x's, followed by T or F to indicate superuserness, followed
 * by the numeric oid, followed by a comma, followed by the role name.
 * This cannot be confused with a plain role name because of the NAMEDATALEN
 * limit on names, so we can tell whether we're being passed an initial
 * role name or a saved/restored value.  (NOTE: we rely on guc.c to have
 * properly truncated any incoming value, but not to truncate already-stored
 * values.  See GUC_IS_NAME processing.)
 */
extern char *session_authorization_string;		/* in guc.c */

const char *
assign_session_authorization(const char *value, bool doit, GucSource source)
{
	Oid			roleid = InvalidOid;
	bool		is_superuser = false;
	const char *actual_rolename = NULL;
	char	   *result;

	if (strspn(value, "x") == NAMEDATALEN &&
		(value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'))
	{
		/* might be a saved userid string */
		Oid			savedoid;
		char	   *endptr;

		savedoid = (Oid) strtoul(value + NAMEDATALEN + 1, &endptr, 10);

		if (endptr != value + NAMEDATALEN + 1 && *endptr == ',')
		{
			/* syntactically valid, so break out the data */
			roleid = savedoid;
			is_superuser = (value[NAMEDATALEN] == 'T');
			actual_rolename = endptr + 1;
		}
	}

	if (roleid == InvalidOid)
	{
		/* not a saved ID, so look it up */
		HeapTuple	roleTup;

		if (!IsTransactionState())
		{
			/*
			 * Can't do catalog lookups, so fail.  The upshot of this is that
			 * session_authorization cannot be set in postgresql.conf, which
			 * seems like a good thing anyway.
			 */
			return NULL;
		}

		roleTup = SearchSysCache(AUTHNAME,
								 PointerGetDatum(value),
								 0, 0, 0);
		if (!HeapTupleIsValid(roleTup))
		{
			if (source >= PGC_S_INTERACTIVE)
				ereport(ERROR,
						(errcode(ERRCODE_UNDEFINED_OBJECT),
						 errmsg("role \"%s\" does not exist", value)));
			return NULL;
		}

		roleid = HeapTupleGetOid(roleTup);
		is_superuser = ((Form_pg_authid) GETSTRUCT(roleTup))->rolsuper;
		actual_rolename = value;

		ReleaseSysCache(roleTup);
	}

	if (doit)
		SetSessionAuthorization(roleid, is_superuser);

	result = (char *) malloc(NAMEDATALEN + 32 + strlen(actual_rolename));
	if (!result)
		return NULL;

	memset(result, 'x', NAMEDATALEN);

	sprintf(result + NAMEDATALEN, "%c%u,%s",
			is_superuser ? 'T' : 'F',
			roleid,
			actual_rolename);

	return result;
}

const char *
show_session_authorization(void)
{
	/*
	 * Extract the user name from the stored string; see
	 * assign_session_authorization
	 */
	const char *value = session_authorization_string;
	Oid			savedoid;
	char	   *endptr;

	Assert(strspn(value, "x") == NAMEDATALEN &&
		   (value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'));

	savedoid = (Oid) strtoul(value + NAMEDATALEN + 1, &endptr, 10);

	Assert(endptr != value + NAMEDATALEN + 1 && *endptr == ',');

	return endptr + 1;
}


/*
 * SET ROLE
 *
 * When resetting session auth after an error, we can't expect to do catalog
 * lookups.  Hence, the stored form of the value must provide a numeric oid
 * that can be re-used directly.  We implement this exactly like SET
 * SESSION AUTHORIZATION.
 *
 * The SQL spec requires "SET ROLE NONE" to unset the role, so we hardwire
 * a translation of "none" to InvalidOid.
 */
extern char *role_string;		/* in guc.c */

const char *
assign_role(const char *value, bool doit, GucSource source)
{
	Oid			roleid = InvalidOid;
	bool		is_superuser = false;
	const char *actual_rolename = value;
	char	   *result;

	if (strspn(value, "x") == NAMEDATALEN &&
		(value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'))
	{
		/* might be a saved userid string */
		Oid			savedoid;
		char	   *endptr;

		savedoid = (Oid) strtoul(value + NAMEDATALEN + 1, &endptr, 10);

		if (endptr != value + NAMEDATALEN + 1 && *endptr == ',')
		{
			/* syntactically valid, so break out the data */
			roleid = savedoid;
			is_superuser = (value[NAMEDATALEN] == 'T');
			actual_rolename = endptr + 1;
		}
	}

	if (roleid == InvalidOid &&
		strcmp(actual_rolename, "none") != 0)
	{
		/* not a saved ID, so look it up */
		HeapTuple	roleTup;

		if (!IsTransactionState())
		{
			/*
			 * Can't do catalog lookups, so fail.  The upshot of this is that
			 * role cannot be set in postgresql.conf, which seems like a good
			 * thing anyway.
			 */
			return NULL;
		}

		roleTup = SearchSysCache(AUTHNAME,
								 PointerGetDatum(value),
								 0, 0, 0);
		if (!HeapTupleIsValid(roleTup))
		{
			if (source >= PGC_S_INTERACTIVE)
				ereport(ERROR,
						(errcode(ERRCODE_UNDEFINED_OBJECT),
						 errmsg("role \"%s\" does not exist", value)));
			return NULL;
		}

		roleid = HeapTupleGetOid(roleTup);
		is_superuser = ((Form_pg_authid) GETSTRUCT(roleTup))->rolsuper;

		ReleaseSysCache(roleTup);

		/*
		 * Verify that session user is allowed to become this role
		 */
		if (!is_member_of_role(GetSessionUserId(), roleid))
		{
			if (source >= PGC_S_INTERACTIVE)
				ereport(ERROR,
						(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
						 errmsg("permission denied to set role \"%s\"",
								value)));
			return NULL;
		}
	}

	if (doit)
		SetCurrentRoleId(roleid, is_superuser);

	result = (char *) malloc(NAMEDATALEN + 32 + strlen(actual_rolename));
	if (!result)
		return NULL;

	memset(result, 'x', NAMEDATALEN);

	sprintf(result + NAMEDATALEN, "%c%u,%s",
			is_superuser ? 'T' : 'F',
			roleid,
			actual_rolename);

	return result;
}

const char *
show_role(void)
{
	/*
	 * Extract the role name from the stored string; see assign_role
	 */
	const char *value = role_string;
	Oid			savedoid;
	char	   *endptr;

	/* This special case only applies if no SET ROLE has been done */
	if (value == NULL || strcmp(value, "none") == 0)
		return "none";

	Assert(strspn(value, "x") == NAMEDATALEN &&
		   (value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'));

	savedoid = (Oid) strtoul(value + NAMEDATALEN + 1, &endptr, 10);

	Assert(endptr != value + NAMEDATALEN + 1 && *endptr == ',');

	/*
	 * Check that the stored string still matches the effective setting, else
	 * return "none".  This is a kluge to deal with the fact that SET SESSION
	 * AUTHORIZATION logically resets SET ROLE to NONE, but we cannot set the
	 * GUC role variable from assign_session_authorization (because we haven't
	 * got enough info to call set_config_option).
	 */
	if (savedoid != GetCurrentRoleId())
		return "none";

	return endptr + 1;
}