Allow loadable modules to create PGC_POSTMASTER GUC variables, but only

when loaded via shared_preload_libraries.  Needed for support of
pg_stat_statements, or pretty much anything else that wants a GUC to
control size of a shared memory allocation.
This commit is contained in:
Tom Lane 2009-01-03 20:03:08 +00:00
parent dad75a62bf
commit 4605d1c98b
3 changed files with 29 additions and 4 deletions

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.170 2009/01/01 17:23:51 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.171 2009/01/03 20:03:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1131,6 +1131,9 @@ ValidatePgVersion(const char *path)
char *shared_preload_libraries_string = NULL;
char *local_preload_libraries_string = NULL;
/* Flag telling that we are loading shared_preload_libraries */
bool process_shared_preload_libraries_in_progress = false;
/*
* load the shared libraries listed in 'libraries'
*
@ -1197,9 +1200,11 @@ load_libraries(const char *libraries, const char *gucname, bool restricted)
void
process_shared_preload_libraries(void)
{
process_shared_preload_libraries_in_progress = true;
load_libraries(shared_preload_libraries_string,
"shared_preload_libraries",
false);
process_shared_preload_libraries_in_progress = false;
}
/*

View File

@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.487 2009/01/02 10:33:20 mha Exp $
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.488 2009/01/03 20:03:08 tgl Exp $
*
*--------------------------------------------------------------------
*/
@ -5625,6 +5625,17 @@ init_custom_variable(const char *name,
{
struct config_generic *gen;
/*
* Only allow custom PGC_POSTMASTER variables to be created during
* shared library preload; any later than that, we can't ensure that
* the value doesn't change after startup. This is a fatal elog if it
* happens; just erroring out isn't safe because we don't know what
* the calling loadable module might already have hooked into.
*/
if (context == PGC_POSTMASTER &&
!process_shared_preload_libraries_in_progress)
elog(FATAL, "cannot create PGC_POSTMASTER variables after startup");
gen = (struct config_generic *) guc_malloc(ERROR, sz);
memset(gen, 0, sz);
@ -5707,7 +5718,15 @@ define_custom_variable(struct config_generic * variable)
case PGC_S_ENV_VAR:
case PGC_S_FILE:
case PGC_S_ARGV:
phcontext = PGC_SIGHUP;
/*
* If we got past the check in init_custom_variable, we can
* safely assume that any existing value for a PGC_POSTMASTER
* variable was set in postmaster context.
*/
if (variable->context == PGC_POSTMASTER)
phcontext = PGC_POSTMASTER;
else
phcontext = PGC_SIGHUP;
break;
case PGC_S_DATABASE:
case PGC_S_USER:

View File

@ -13,7 +13,7 @@
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.207 2009/01/01 17:23:55 momjian Exp $
* $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.208 2009/01/03 20:03:08 tgl Exp $
*
* NOTES
* some of the information in this file should be moved to other files.
@ -328,6 +328,7 @@ extern void BaseInit(void);
/* in utils/init/miscinit.c */
extern bool IgnoreSystemIndexes;
extern PGDLLIMPORT bool process_shared_preload_libraries_in_progress;
extern char *shared_preload_libraries_string;
extern char *local_preload_libraries_string;