Invent PGC_SU_BACKEND and mark log_connections/log_disconnections that way.

This new GUC context option allows GUC parameters to have the combined
properties of PGC_BACKEND and PGC_SUSET, ie, they don't change after
session start and non-superusers can't change them.  This is a more
appropriate choice for log_connections and log_disconnections than their
previous context of PGC_BACKEND, because we don't want non-superusers
to be able to affect whether their sessions get logged.

Note: the behavior for log_connections is still a bit odd, in that when
a superuser attempts to set it from PGOPTIONS, the setting takes effect
but it's too late to enable or suppress connection startup logging.
It's debatable whether that's worth fixing, and in any case there is
a reasonable argument for PGC_SU_BACKEND to exist.

In passing, re-pgindent the files touched by this commit.

Fujii Masao, reviewed by Joe Conway and Amit Kapila

1 files changed, 12 insertions, 8 deletions

diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 0a729c1190..66b5cd36c5 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -36,15 +36,17 @@
  * certain point in their main loop. It's safer to wait than to read a
  * file asynchronously.)
  *
- * BACKEND options can only be set at postmaster startup, from the
- * configuration file, or by client request in the connection startup
- * packet (e.g., from libpq's PGOPTIONS variable).  Furthermore, an
- * already-started backend will ignore changes to such an option in the
- * configuration file.  The idea is that these options are fixed for a
- * given backend once it's started, but they can vary across backends.
+ * BACKEND and SU_BACKEND options can only be set at postmaster startup,
+ * from the configuration file, or by client request in the connection
+ * startup packet (e.g., from libpq's PGOPTIONS variable).  SU_BACKEND
+ * options can be set from the startup packet only when the user is a
+ * superuser.  Furthermore, an already-started backend will ignore changes
+ * to such an option in the configuration file.  The idea is that these
+ * options are fixed for a given backend once it's started, but they can
+ * vary across backends.
  *
  * SUSET options can be set at postmaster startup, with the SIGHUP
- * mechanism, or from SQL if you're a superuser.
+ * mechanism, or from the startup packet or SQL if you're a superuser.
  *
  * USERSET options can be set by anyone any time.
  */
@@ -53,6 +55,7 @@ typedef enum
 	PGC_INTERNAL,
 	PGC_POSTMASTER,
 	PGC_SIGHUP,
+	PGC_SU_BACKEND,
 	PGC_BACKEND,
 	PGC_SUSET,
 	PGC_USERSET
@@ -195,7 +198,8 @@ typedef enum
 #define GUC_UNIT_TIME			0x7000	/* mask for MS, S, MIN */
 
 #define GUC_NOT_WHILE_SEC_REST	0x8000	/* can't set if security restricted */
-#define GUC_DISALLOW_IN_AUTO_FILE	0x00010000	/* can't set in PG_AUTOCONF_FILENAME */
+#define GUC_DISALLOW_IN_AUTO_FILE	0x00010000	/* can't set in
+												 * PG_AUTOCONF_FILENAME */
 
 /* GUC vars that are actually declared in guc.c, rather than elsewhere */
 extern bool log_duration;