Don't call data type input functions in GUC check hooks

Instead of calling pg_lsn_in() in check_recovery_target_lsn and
timestamptz_in() in check_recovery_target_time, reorganize the
respective code so that we don't raise any errors in the check hooks.
The previous code tried to use PG_TRY/PG_CATCH to handle errors in a
way that is not safe, so now the code contains no ereport() calls and
can operate safely within the GUC error handling system.

Moreover, since the interpretation of the recovery_target_time string
may depend on the time zone, we cannot do the final processing of that
string until all the GUC processing is done.  Instead,
check_recovery_target_time() now does some parsing for syntax
checking, but the actual conversion to a timestamptz value is done
later in the recovery code that uses it.

Reported-by: Andres Freund <[email protected]>
Reviewed-by: Michael Paquier <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/20190611061115.njjwkagvxp4qujhp%40alap3.anarazel.de

1 files changed, 27 insertions, 11 deletions

diff --git a/src/backend/utils/adt/pg_lsn.c b/src/backend/utils/adt/pg_lsn.c
index 7242d3cfed4..eb586851529 100644
--- a/src/backend/utils/adt/pg_lsn.c
+++ b/src/backend/utils/adt/pg_lsn.c
@@ -25,10 +25,9 @@
  * Formatting and conversion routines.
  *---------------------------------------------------------*/
 
-Datum
-pg_lsn_in(PG_FUNCTION_ARGS)
+XLogRecPtr
+pg_lsn_in_internal(const char *str, bool *have_error)
 {
-	char	   *str = PG_GETARG_CSTRING(0);
 	int			len1,
 				len2;
 	uint32		id,
@@ -38,16 +37,16 @@ pg_lsn_in(PG_FUNCTION_ARGS)
 	/* Sanity check input format. */
 	len1 = strspn(str, "0123456789abcdefABCDEF");
 	if (len1 < 1 || len1 > MAXPG_LSNCOMPONENT || str[len1] != '/')
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-				 errmsg("invalid input syntax for type %s: \"%s\"",
-						"pg_lsn", str)));
+	{
+		*have_error = true;
+		return InvalidXLogRecPtr;
+	}
 	len2 = strspn(str + len1 + 1, "0123456789abcdefABCDEF");
 	if (len2 < 1 || len2 > MAXPG_LSNCOMPONENT || str[len1 + 1 + len2] != '\0')
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-				 errmsg("invalid input syntax for type %s: \"%s\"",
-						"pg_lsn", str)));
+	{
+		*have_error = true;
+		return InvalidXLogRecPtr;
+	}
 
 	/* Decode result. */
 	id = (uint32) strtoul(str, NULL, 16);
@@ -58,6 +57,23 @@ pg_lsn_in(PG_FUNCTION_ARGS)
 }
 
 Datum
+pg_lsn_in(PG_FUNCTION_ARGS)
+{
+	char	   *str = PG_GETARG_CSTRING(0);
+	XLogRecPtr	result;
+	bool have_error = false;
+
+	result = pg_lsn_in_internal(str, &have_error);
+	if (have_error)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+				 errmsg("invalid input syntax for type %s: \"%s\"",
+						"pg_lsn", str)));
+
+	PG_RETURN_LSN(result);
+}
+
+Datum
 pg_lsn_out(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	lsn = PG_GETARG_LSN(0);